Maintenance of hydraulic fracturing unit (GRU)

Switching on gas control points (GRP) and installations (GRU). After a break in work (at night or on weekends), the gas distribution unit (GRU) must be turned on in the following order.

• 1. When entering the GRP (GRU) room, make sure that it is not polluted, and be sure to ventilate it by opening the door or windows; check the work ventilation devices.
• 2. Check condition and position locking devices GRP (GRU). All shut-off devices (except for shut-off devices after the regulator, before and after the meters, as well as on the purge pipeline after the regulator) must be closed.
• 3. Open the taps in front of the pressure gauges at the inlet and after the regulator.
• 4. Carefully open the valve at the inlet to the gas distribution unit (GRU) and check for gas pressure sufficient for operation.
• 5. Check the serviceability of the pressure regulator by inspection. For RD-32M and RD-50M regulators, check the weakening of the control spring, the opening of the valve on the impulse tube; for pilot regulators, the weakening of the pilot spring (the pilot adjusting screw must be turned out) and the opening of the valves on the impulse tubes.
• 6. Inspect the safety stop valve PZK, use a lever to lift its plate and secure it in this position with a latch. Do not install the impact hammer yet, since it is impossible to engage it with the membrane lever without gas pressure under it. Check that the valves on the bypass and impulse pipe are closed. If the PKK-40M valve is installed in the hydraulic fracturing unit, then you should unscrew the starting plug slightly and, after waiting a few seconds, screw it back in.
• 7. If there is a liquid relief valve, ensure that it is filled with water to the specified level.
• 8. Open the shut-off devices before and after the meters (if they were closed) and very slowly, observing the readings of the pressure gauge after the regulator, open the shut-off device in front of it.
• 9. After making sure that the regulator is operating stable, lift the impact hammer of the shut-off valve, engage it with the membrane lever, having previously opened the tap on the impulse tube of the shut-off valve.
• 10. Having made sure that the gas is supplied to consumers (or through their purge pipelines), close the purge pipeline of the hydraulic fracturing unit and turn off the water and mercury pressure gauges before leaving, since in the event of a malfunction of the regulator, the liquid from the pressure gauge may be thrown out and the gas fracturing room will be contaminated.

The initial start-up of the gas fracturing unit (GRU) is carried out after testing its pipelines and equipment by the acceptance committee and signing the acceptance certificate, as well as after control pressure testing and purging of the gas pipeline in front of the gas fracturing unit (GRU).

When preparing for the initial start-up, the condition of the premises and all gas equipment of the hydraulic fracturing unit (GRU) is also checked, as described above (paragraphs 1, 3, 5-7).

The slam-shut valve is set to operate at the minimum and maximum pressures specified in the operating instructions. The liquid relief valve is filled with liquid to the specified level. Then carefully open the shut-off device at the inlet, slightly open the shut-off device on the hydraulic fracturing bypass for 20-30 s and purge at the gas pressure allowed by the instructions for this regulator. After this, the regulator is put into operation (item 8) and the required output pressure is set by tensioning the adjusting spring or using a pilot.

After making sure that the regulator is working properly, lift the impact hammer of the shut-off valve and open the tap on the impulse tube to it. If the PKK-40M valve is installed, then turn it on by opening and then closing the starting plug. After adjusting the regulator, the meters and their bypass pipelines are purged together with the gas pipelines from the hydraulic fracturing unit to the units: first through the bypass pipelines of the meters for 3-5 minutes, and then through the meters - 1-2 minutes. To turn on the meters, slowly open the shut-off device after them, then in front of them, and close the shut-off device on the bypass pipeline.

If there is gas flow through the purge pipelines of consumers, turn on the meters and close the valve on the purge pipeline of the hydraulic fracturing unit. If there is a liquid relief valve, open the tap in front of it and check its operation by raising the gas pressure after the regulator to the level required for its “operation”. The latter is determined by the sound of gas bubbling through the liquid. Check the setting of the spring relief valve in the same way.

After putting the gas distribution unit (GRU) into operation, it is necessary to check the tightness of all connections with a soap solution and immediately repair any detected leaks.

Maintenance of the gas distribution unit (GRU) during operation. When accepting a shift, the person servicing the gas distribution center (GRU) must:

• 1) make sure that there is no smell of gas in the fracking room, ventilate it well and check the operation of the ventilation devices and heating of the room;
• 2) check the condition and position of the locking devices. They must not allow gas to pass through the seals and flanges and must be in a position corresponding to the operating mode of the hydraulic fracturing unit (GRU);
• 3) check the condition and operation of the filter, shut-off valve, regulator, relief valve, meters; make sure that there are no gas leaks in the connections of the devices; check the gas pressure using a pressure gauge at the inlet and outlet of the hydraulic fracturing unit (GRU) - it must correspond to that specified in the instructions.

Any deficiencies noticed should be immediately reported to the person responsible for the gas supply. It is forbidden to enter the GRP with fire or a burning cigarette, and also to allow unauthorized persons into it. During the shift, it is necessary to keep records of the operation of the gas distribution unit (GRU), promptly record in the shift log any malfunctions and interruptions in its operation, start-up and stop times, as well as hourly readings of the meter and pressure gauges at the inlet and outlet of the GRU (GRU). When leaving the hydraulic fracturing room, you should turn off liquid pressure gauges and lock the room with a key.

To transfer the gas distribution unit (GRU) to work through a bypass line during repair or revision of the regulator, slam-shut valve or filters, you should:

• 1) notify the duty operators about this;
• 2) carefully disengage the slam-shut hammer and close the valve on its impulse line;
• 3) slowly and carefully, following the pressure gauge readings, slightly open the shut-off device on the bypass line and increase the gas pressure at the outlet of the hydraulic fracturing unit (GRU) at low pressure by 100-200 Pa above the set mode (at medium pressure - 1300 -2600 Pa);
• 4) slowly close the shut-off device in front of the regulator, observing the pressure gauge readings. If the pressure decreases, open the shut-off device on the bypass line slightly so that the pressure is maintained constant at the specified level. If a regulator with pilot control is installed in the gas distribution unit (GRU), then you should first slowly turn out the pilot adjusting screw completely (counterclockwise), and then close the shut-off device in front of the regulator;
• 5) when the shut-off device in front of the regulator is completely closed, use a shut-off device on the bypass line to reduce the pressure behind the hydraulic fracturing unit (GRU) by 100-200 Pa at low pressure (at average pressure - 1300-2600 Pa) and then adjust it according to the pressure gauge readings . If there are 2 shut-off devices on the bypass line, then the first one makes a partial (rough) reduction in gas pressure along the gas flow, and the second one makes a more precise adjustment;
• 6) turn off the safety valve;
• 7) close the shut-off device after the regulator;

For long-term (more than 7 days) operation of the hydraulic fracturing unit (GRU) on the bypass line (with the regulator turned off), special permission from Rostekhnadzor authorities is required.

To transfer the hydraulic fracturing unit (GRU) from the bypass line to operation through the regulator, it is necessary:

• 1) check the setting of the shut-off valve for operation and raise its shut-off element;
• 2) warn the operators on duty about the transfer of the hydraulic fracturing unit to work through the regulator;
• 3) inspect the regulator, make sure it is in good condition and the valves on the impulse lines are open (the adjusting screw of the regulator pilot must be turned out);
• 4) open the locking device behind the regulator;
• 5) reduce the gas pressure at the outlet of the hydraulic fracturing unit (GRU) by slowly closing the shut-off device on the bypass by 100-200 Pa at low pressure and by 1300-2600 Pa at medium pressure;
• 6) very slowly open the shut-off device in front of the regulator, observing the readings of the pressure gauge behind the regulator;
• 7) set the required gas pressure by screwing in the adjusting spring of the regulator or its pilot;
• 8) slowly close the shut-off device on the bypass line;
• 9) make sure that the regulator operates stably, open the valve on the impulse line of the shut-off valve and engage the impact hammer with the diaphragm lever.

When shutting down the gas distribution unit (GRU) due to the activation of the slam-shut valve, which can be caused by damage to the regulator, a shock or shock, incorrect setting of the slam-shut valve, interruption of the gas supply or a decrease in its pressure at the inlet to the gas fracturing unit (GRU) and a sudden shutdown of consumers, you should:

• 1) make sure that the operating and control shut-off devices in front of the burners and igniters are closed, and the valves on the safety and purge pipelines are open;
• 2) close the shut-off device in front of the regulator;
• 3) unscrew the adjusting screw of the regulator;
• 4) find out and eliminate the reason for the operation of the slam-shut valve and, if there is sufficient gas pressure at the inlet to the gas distribution unit (GRU), open the bypass line, lift the valve plate on the body of the closed slam-shut valve, and then close the bypass line; if the PKK-40M valve is installed, then put it into operation by opening and then closing the start button;
• 5) slowly and smoothly open the shut-off device in front of the regulator, observing the gas pressure after it, and adjust the required pressure with the adjusting screw or pilot;
• 6) open the tap on the impulse line of the shut-off valve, engage the impact hammer and, after making sure that the hydraulic fracturing unit (GRU) is operating stable, proceed to start up the burners.

Turning off the hydraulic fracturing unit (GRU). To turn off the hydraulic fracturing unit (GRU), you should:

• 1) carefully disengage the slam-shut hammer and close the valve on its impulse line;
• 2) close the shut-off device at the inlet to the gas distribution unit (GRU) and make sure that the gas pressure at the inlet decreases to zero;
• 3) close the locking device in front of the regulator, loosen the adjustment spring in regulators of the RD-ZM and RD-50M types, and in pilot regulators, turn out the pilot screw completely;
• 4) lower the slam-shut plate;
• 5) turn off the pressure gauges and open the tap on the spark plug after the regulator;
• 6) if the hydraulic fracturing unit (GRU) was operating on the bypass line, close the valves at the inlet and then on the bypass line.

When turning off the gas distribution unit (GRU) and connecting the relief valve to the gas pipeline after the meters, the shut-off device behind the regulator can be left open to prevent the possibility of rupture of the regulator membrane (if it does not have a built-in safety valve) or the pilot high blood pressure gas if it is passed through the regulator spool and the shut-off device in front of it.

Preventive maintenance and repair of hydraulic fracturing units (GRU). A scheduled check of the condition of the hydraulic fracturing (GRU) equipment is carried out under the guidance of engineers at the following times: with spring regulators, as a rule, 4 times a year, with indirect-acting and pilot regulators - 6 times a year, Maintenance And Maintenance regulators with a guaranteed service life can be produced in accordance with the manufacturer's passport (instructions).

Prevention of hydraulic fracturing (GRU) is carried out on a daily basis: maintenance personnel receive equipment on shift and monitor its operation; the person responsible for the gas industry visits the gas distribution center daily and checks the operation of the equipment monthly; equipment operation is also tested and repaired within the time limits established by the schedule.

Inspection technical condition(bypass) Hydraulic fracturing should, as a rule, be carried out by two workers.

Bypassing gas distribution units equipped with telemechanics systems, equipped with gas alarms with controlled signal output, cabinet-mounted control points, as well as main control units can be carried out by one worker.

When performing preventive maintenance of hydraulic fracturing (GRU), it is necessary to:

• 1) monitor the proper operation of the regulator, its cleanliness, lubrication of rubbing parts, the tightness of membranes, impulse and breathing tubes, seals of locking devices, etc. When disassembling it, all parts of the regulator should be cleaned of dirt and dust, worn bushings and pins of the lever joints should be replaced and lubricated well, check the tightness of the spool to the seat and, if necessary, grind it in. Inspect the membrane, clean it from dust and dirt. The regulator's impulse and breathing tubes must be internally cleaned and purged with air;
• 2) monitor the proper operation of the slam-shut valve, check it “for operation” at least once every three months, with a record of the check performed in the preventive inspection and repair log. Keep the valve seal clean, promptly lubricate the rubbing parts and the head membrane (if it is made of leather). Do not allow gas to pass through leaks in seals, flanges, impulse tubes, and taps. Raising and lowering of the spool must occur without jamming. Produce at least once a year internal inspection valve with cleaning of its parts, lubrication, replacement of the oil seal packing on the axis of the valve lever and checking the tightness of the spool closure. Also check the tightness of the bypass, the valve of the impulse tube, the cleanliness of the tube inside and the condition of the membrane and levers in the valve head;
• 3) observe the degree of filter clogging, checking it by pressure difference using a differential pressure gauge; monitor the absence of gas leaks in the differential pressure gauge, which should turn on only when checking the filter resistance; check the internal condition of the filter as the pressure drop increases, and therefore the filter becomes clogged. In this case, it is necessary to clean the housing from dust and rust, clean the mesh cartridge (in the mesh filter) or replace the cassette (in the cassette filter) with a new one. Disassembly and cleaning of the filter cassette must be carried out outside the hydraulic fracturing unit in places at least 5 m away from flammable substances and materials;
• 4) monitor the condition of the shut-off devices (their cleanliness, lubrication, condition of the seals, ease of movement, tight closure and absence of gas leakage); At least once a year, disassemble the valves, clean their parts from dirt, and wash them with kerosene; check the condition of locking surfaces, sealing rings, spacer wedges and ensure their tight closure by lapping and scraping the surfaces of the discs; it is also necessary to check the condition of the spindle and nut;
• 5) monitor the proper operation and timely lubrication of meter mechanisms, as well as the good condition and operation of pressure gauges and other instrumentation;
• 6) monitor the proper operation of spring or liquid relief valves, the constant presence of liquid in the latter at a given level;
• 7) monitor the operation of ventilation and heating devices, explosive lighting, as well as the state of air in the gas distribution center; At least 2 times a month, during a routine inspection, take an air sample to check it for the content of flammable components and check with a soap solution the tightness of all connections of the gas pipelines of the hydraulic fracturing and gas distribution system.

Repair work in the hydraulic fracturing room is considered gas hazardous and is carried out by 2 workers under the supervision of a person from among the engineering and technical personnel, as well as 1 worker located outside. Work should be performed only with serviceable and explosion-proof tools using explosion-proof lighting and, if necessary, gas masks. When dismantling or opening equipment, it is necessary to install plugs separating the area being repaired.

Welding in the gas distribution facility is permitted with the permission of the person responsible for the gas facilities of the enterprise, after checking the cleanliness of the air by chemical analysis. The use of welding on hydraulic fracturing gas pipelines is permissible only after turning it off with a shut-off device at the inlet, installing a plug and purging the gas pipelines with inert gas (nitrogen, carbon dioxide) followed by analysis of the gas sample.

Gas control points (GRP) and gas control units(GRU) are designed to reduce the inlet gas pressure to a given output (working) and maintain it constant regardless of changes in inlet pressure and gas consumption. Fluctuations in gas pressure at the outlet of the hydraulic fracturing unit (GRU) are allowed within 10% of the operating pressure. The gas fracturing unit (GRU) also carries out gas purification from mechanical impurities, control of inlet and outlet pressure and gas temperature, protection of operating pressure from increase or decrease, and gas flow metering.

Depending on the gas pressure at the inlet, hydraulic fracturing (GRU) is distinguished between medium (more than 0.005 to 0.3 MPa) and high (more than 0.3 to 1.2 MPa) pressure. Gas control points can be located in separate buildings, built into one-story industrial buildings, or located in cabinets on external fireproof walls on separate supports (cabinet GRP).

Gas control units are located in gasified buildings directly in the premises of boiler rooms or workshops where gas-using units are located, or in adjacent rooms that have at least three air changes per hour and are connected to the first open opening. Gas supply from the GRU to consumers in other separate buildings is not permitted. The basic technological diagrams of hydraulic fracturing and gas distribution units are similar (Fig.) and further consideration is carried out only for hydraulic fracturing.

Drawing. Schematic diagram of the gas control point (installation):

1 - safety relief valve(reset device); 2 - valves on the bypass line; 3 - pressure gauges; 4 - impulse line of the SCP; 5 - purge gas pipeline; 6 - bypass line; 7 - gas flow meter; 8 - gate valve at the inlet; 9 - filter; 10 - safety shut-off valve (SCV); 11 - gas pressure regulator; 12 - gate valve at the outlet.

Three lines can be distinguished in the hydraulic fracturing system: main, bypass 6 (bypass) and working.

On the main line, gas equipment is located in the following sequence:

Shut-off device at the inlet (valve 8);

Purge gas pipeline 5;

Filter 9 for purifying gas from possible mechanical impurities;

Safety shut-off valve (SSV) 10, which automatically turns off the gas supply when the gas pressure in the operating line increases or decreases beyond the established limits;

Gas pressure regulator 11, which reduces the gas pressure on the working line and automatically maintains it at a given level regardless of gas consumption by consumers;

Shut-off device (valve 12) at the outlet of the main line.

The bypass line has a purge gas pipeline 5, two shut-off devices (valves 2), one of which is used to manually regulate the gas pressure in the working line during execution repair work on a disconnected main line. A safety relief valve 1 (PSV) is installed on the working pressure line (working line), which serves to discharge gas through a relief plug into the atmosphere when the gas pressure in the working line increases above the set limit.

The following control and measuring instruments are installed in the gas distribution center:

Thermometers for measuring gas temperature and in the hydraulic fracturing room;

Gas flow meter 7 (gas meter, throttle flow meter);

3 pressure gauges for measuring gas inlet pressure, pressure in the working line, pressure at the inlet and outlet of the gas filter.

Burners without pre-mixing gas with air.

In burners without pre-mixing, gas and air are mixed outside the burner and burned in an extended diffusion torch.

Their main advantages are as follows:

Very high control limits, since the possibility of flame penetration into the burner is excluded;

A sufficiently high temperature for heating the gas and air supplied through the burner, since it is limited only by the durability of the supply pipelines and the danger of thermal decomposition of the gas;

Delete an area high temperatures from the masonry and adjacent to the working space of the furnace metal parts burners increases the durability of the latter and the burner stone, especially when burning gas with high thermal power;

The absence of internal mixing makes it possible to significantly reduce dimensions and create burners with very high thermal power.

Burners without pre-mixing also have a number of disadvantages:

It is necessary to supply air with the help of fans through an air duct system, spending the corresponding capital investments and electricity;

It is necessary to adjust the ratio of gas and air;

Imperfect mixing of gas and air leads to the need to work with an increased air flow rate, which is associated with a slight decrease in calorimetric temperature and an increase in fuel consumption.

GRS

Gas distribution stations (GDS) must ensure the supply of gas to consumers (enterprises and populated areas) in a specified amount with a certain pressure, degree of purification and odorization.

To supply gas to populated areas and industrial enterprises from gas pipelines, branches are constructed through which gas is supplied to the gas distribution station.

The following main technological processes are carried out at the GDS:

Gas purification from solid and liquid impurities;

Reducing pressure (reduction);

Odorization;

Accounting for the amount (consumption) of gas before supplying it to the consumer.

The main purpose of the gas distribution system is to reduce gas pressure and maintain it at a given level. Gas with a pressure of 0.3 and 0.6 MPa is supplied to city gas distribution points, consumer gas control points, and with a pressure of 1.2 and 2 MPa - to special consumers (CHP, state district power station, CNG filling station, etc.). At the output of the gas distribution station, the supply of a given amount of gas must be ensured while maintaining the operating pressure in accordance with the agreement between the gas treatment facility and the consumer with an accuracy of up to 10%.

Reliability and safety of GDS operation must be ensured by:

1. Periodic monitoring of the condition technological equipment and systems;

2. keeping them in in good condition due to timely implementation of repair and maintenance work;

3. Timely modernization and renovation of morally and physically worn-out equipment and systems;

4. Compliance with zone requirements minimum distances to populated areas, industrial and agricultural enterprises, buildings and structures;

5. Timely warning and elimination of failures.

Commissioning of a gas distribution station after construction, reconstruction and modernization without commissioning is prohibited.

For newly developed equipment, GDS system automatic control must provide:

Inclusion of a reserve reducing thread in the event of failure of one of the workers;

Disabling a failed reducing thread;

Alarm about switching of reducing threads.

Each gas distribution system must be stopped once a year to perform maintenance and repair work.

The procedure for admitting unauthorized persons to the gas distribution station and the entry of vehicles is determined by the division of the production association.

At the entrance to the GDS territory, a sign must be installed with the name (number) of the GDS, indicating its division and production association, the position and surname of the person responsible for the operation of the GDS.

Available at GDS security alarm must be kept in good condition.

Burners with incomplete pre-mixing of gas and air.

In this case, the gas does not completely mix with the air in front of the outlets. With partial preliminary mixing of gas with air. They absorb primary air due to the energy of the gas stream. The missing part of the air is supplied to the combustion site from environment. Used in devices gas stoves, small heating devices and water heaters, as well as in low-power boilers.

Gas appliances installed in residential and public buildings.

Gas is supplied to residential, public and municipal buildings through gas pipelines from the city distribution network. These gas pipelines consist of customer branches that supply gas to the building and intra-house gas pipelines that transport gas inside the building and distribute it between individual equipment. In domestic gas networks Residential, public and communal buildings are allowed to transport only low pressure gas.

The gas pipeline is introduced into residential and public buildings directly into the premises in which the equipment is installed, or through non-residential premises accessible for pipe inspection. At the entrance of the gas pipeline into the building, a disconnecting device is installed, which is mounted, as usual, outside the building. Gas distribution pipelines are usually laid under the ceiling of the first floor along non-residential premises. Gas risers are laid in kitchens or corridors.

A section of an external gas pipeline laid along the facade of the building, a shut-off device at the entrance to the building in the presence of a cabinet gas control point is installed on the wall of the building - from the place of its connection at the outlet) to the internal gas pipeline; gas appliances and devices installed in residential or public building, as well as in the room attached to them and a separate furnace building.

Gas control points (GRP) or installations (GRU) are designed to: reduce gas pressure to a given value; maintaining a given pressure regardless of changes in gas flow and pressure at the inlet to gas control points or gas control units; stopping the gas supply when its pressure increases or decreases after hydraulic fracturing or gas distribution in excess of established standards.

The difference between GRU and GRU is that the former are built directly at consumers and are intended to supply gas to boilers and other units located in only one room, while gas control points are equipped at city gas distribution networks or municipal facilities. Schematic diagrams GRP and GRU are similar.

Gas control equipment can be located in a separate building, in a room built into the boiler room, or in metal cabinets outside the building. In the latter case, the installation is called “cabinet gas control points” (GRP). Lightning protection of the gas distribution facility is necessary in cases where the gas distribution building does not fall within the lightning protection zone of neighboring facilities. In this case, a lightning rod is installed. If the GRP building is located in the lightning protection zone of other facilities, then only a grounding loop will be installed in it. The fracking room is equipped with firefighting equipment and devices (a box of sand, fire extinguishers, fire felt, etc.).

Gas hydraulic fracturing equipment. The hydraulic fracturing equipment set includes: a filter for purifying gas from mechanical impurities; a safety shut-off valve that automatically turns off the gas supply to consumers in the event of a failure of the gas pressure regulator; gas pressure regulator, which reduces gas pressure and automatically maintains it at a given level; safety-relief valve (hydraulic or spring) at the gas outlet, which ensures the release of excess gas in the event of an increase in gas pressure above the permissible f- (working) at the outlet of the GRN. and pressure gauges for measuring gas pressure at the inlet and outlet of the hydraulic fracturing system.

The main line on which the gas equipment is located is equipped with a bypass gas pipeline (bypass) with two valves, with the help of which, in the event of a malfunction in the main line, the gas pressure is manually regulated. Rotary meters are installed at the outlet gas control points of small capacity to measure the amount of gas consumed. To vent gas, purge gas pipelines (candles) are installed. The placement of hydraulic fracturing equipment is shown in Fig. 79.

Types of pressure regulators, pressure regulators are the main devices of hydraulic fracturing. They differ in size, design, range of input and output pressures, methods of setting, adjustment, etc. Gas pressure regulators are divided into regulators: direct action, using gas energy in the gas pipeline; indirect action, operating on energy from external sources (pneumatic, hydraulic and electrical); intermediate type, using gas energy in gas pipelines equipped with amplifiers, like indirect-acting regulators.

Direct-acting regulators are most widely used in gas supply systems for heating boiler houses, as they are the simplest and most reliable in operation. In turn, these regulators are divided into pilot and unmanned. Pilot regulators have a control device (pilot) and differ from unmanned ones in their larger size and throughput.

The main structural unit of all direct-acting regulators is the valve. Regulator valves can be with a hard seal (metal to metal) or soft (rubber and leather) valves with a soft seal will more accurately withstand the set pressure behind the regulator. The flow capacity of the regulator depends on the size of the valve and the size of its stroke, therefore one or another design of the regulator is selected according to the maximum possible gas consumption, as well as the size of the valve and the size of its stroke. The cross-sectional area of ​​the seat is 16-20% of the cross-sectional area of ​​the inlet fitting. Maximum distance the distance the valve can extend from the seat is 25-30% of the diameter of its seat. The throughput of the regulator also depends on the pressure drop, i.e., on the pressure difference before and after the regulator, gas density and final pressure. In the instructions and reference books there are tables of the capacity of the regulators with a difference of 1000 mm of water. Art. To determine the capacity of the regulators, it is necessary to do a recalculation. Some of the most common types of RD and RDUK regulators are discussed below.

RD regulators. They are used for low-capacity hydraulic fracturing and are unmanned. They are marked by nominal diameter: RD-20, RD-25. RD-32 and RD-50.
the maximum gas throughput of the first three types is 50 m 3 / h and the last one is 150 m 3 / h.

The first three types have the same dimensions and differ only in the connecting dimensions of the inlet and outlet pipes. RD-20 regulators are not manufactured.
IN Lately Modernized regulators RD-32M and RD-50M were released, each having two inlet fittings. The design and principle of operation of these regulators are the same. In Fig. 80 shows the device of the RD-32M regulator.

The principle of its operation is as follows: as gas consumption decreases, the pressure after the regulator begins to increase. This is transmitted through an impulse tube under the membrane. The membrane, under gas pressure, goes up, compressing the spring until the forces of gas pressure and the spring are balanced. The upward movement of the membrane is transmitted by a system of levers to the valve, which covers the hole for the passage of gas. As a result, the gas pressure decreases to a predetermined value.

As gas consumption increases, the pressure after the regulator begins to drop. This is transmitted through an impulse tube under the membrane, which, under the action of a spring, goes down, and through a system of levers the valve opens. The passage for gas increases, and the gas pressure after the regulator is restored to the set value. The capacity of the RD-32M and RD-50M regulators is 190 and 780 m/h. RDUK regulators. In operation, regulators RDUK-2-50, RDUK-2-100 and RDUK-2-200 are used, which differ from one another in the nominal diameter of 50, 100 and 200 mm, respectively. The maximum flow rates of these regulators are 6600, 17850 and 44800 m/h.

RDUK regulators (Fig. 81) are installed complete with regulators (pilots) KN-2 (low pressure) and KV-2 ( high pressure). To obtain a gas outlet pressure in the range of 0.5-60 kPa (50-6000 mm water column), a KN-2 pilot is used, and in the range of 0.06-0.6 MPa (0.6-6 kgf/cm) - KV-2 pilot.

The operation of the RDUK regulator is carried out as follows: as gas consumption decreases, the pressure after the regulator begins to increase. This is transmitted through impulse tube 1 to the pilot membrane, which, moving down, closes the pilot valve. The passage of gas through the pilot through impulse tube 2 stops, so the gas pressure under the regulator membrane also drops. When the pressure under the RDUK membrane becomes less than the mass of the plate and the pressure exerted by the regulator valve, the membrane will go down, displacing gas from under the cavity membrane through impulse tube 3 to the discharge. The valve begins to close, reducing the opening for gas passage. The pressure after the regulator will decrease to the set value.

As gas consumption increases, the pressure after the regulator begins to fall. This is transmitted through the impulse tube to the membrane to the pilot. The pilot membrane goes up under the action of the spring; open the pilot valve; gas from the high side flows through impulse tube 2 to the pilot valve and then through impulse tube 3 goes under the regulator membrane. Part of the gas is discharged through impulse tube 4, and part under the membrane.

The gas pressure under the regulator membrane increases and, overpowering the mass of the load plate and the force of the valve, forces it to move upward. The regulator valve opens, increasing the opening for gas passage. The pressure after the regulator increases to the specified value.

When the gas pressure in front of the regulator increases beyond established norm the latter operates similarly to the operation of this device with reduced gas consumption. Regulator safety devices. These devices are installed in front of the gas pressure regulator. Their membrane head is connected to a final pressure gas pipeline through an impulse tube. When the operating gas pressure increases or decreases above or below the established standards, safety shut-off valves automatically cut off the gas supply to the regulator.

Safety-relief devices used in gas control points ensure the release of excess gas in the event of a loose closing of the safety-shut-off valve or regulator. Safety-relief devices are installed on the outlet pipe of the gas pipeline (after the regulator) and connected to a separate spark plug with an inlet fitting. When the gas pressure increases above the established norm, its excess is discharged into the spark plug.

The permissible increase in inlet pressure to which the relief device is set must be less than for the safety shut-off valve.
Safety shut-off valve. The most common of them are low-pressure (PKN) and high-pressure (PKV) safety valves. The PKV safety shut-off valve (Fig. 82) has inlet and outlet flanges on the body. Inside the body there is a seat on which a valve with a soft seal sits on top.

The equalizing valve of the PKV is built into the body of the main valve, which is how it differs from the PC old design. To raise the main valve, I first open the equalizing valve. Gas, entering under the main valve through the equalizing valve, equalizes the pressure before and after the main valve, which then easily rises.

A system of levers connects the main valve to a sensing head located at the top of the PCV, which operates these levers to close the valve. As a result, the valve is additionally pressed against the seat by gas pressure. The sensitive part of the head is a membrane, on which a load presses from above, and from below gas, flowing through the impulse tube from the low pressure side. There is a spring located above the membrane, which does not act on the membrane, which is in its normal middle position.

When lifted up, the membrane rests against the spring. As it rises further, the spring begins to compress, counteracting the movement of the membrane. The compression of the spring can be adjusted by a glass located in the upper part of the head. The membrane rod is connected by a horizontal lever to a hammer. The safety shut-off valve operates as follows: an increase in pressure above the permissible value in the gas pipeline (after the regulator) is transmitted through an impulse tube under the PCV membrane, which rises upward, overcoming the weight of the load and the resistance of the spring. The horizontal lever connected to the diaphragm rod comes into motion and disengages from the hammer. The hammer falls and hits the lever connected to the main valve rod, which closes, blocking the gas passage.

A decrease in pressure above the permissible value in the gas pipeline (after the regulator) is transmitted through the impulse tube under the membrane, which begins to fall under the influence of the load. In this case, the adhesion of the horizontal lever to the hammer is again broken. The hammer falls and the main PCV valve closes. The low pressure safety valve PKN differs from the high pressure safety valve PKV in that it does not have a support ring limiting the working surface of the membrane. In addition, the plate on the membrane of the PKN has a larger diameter.

Relief safety devices. An increase in gas pressure after the regulator is dangerous for the gas pipeline and devices installed on it. It may decrease somewhat when the relief safety devices operate. Discharge safety devices, unlike safety shut-off devices, do not shut off the gas supply, but only discharge part of it into the atmosphere, reducing the gas pressure in the gas pipeline by increasing its flow rate.

There are hydraulic, lever-load, spring and membrane-spring safety relief devices. Hydraulic relief fuse (hydraulic seal) (Fig. 83). Most common when using low pressure gas. It is simple and reliable in operation.

Membrane-spring relief valve PSK (Fig. 84) Unlike a hydraulic seal, it is smaller in size and can operate at low and medium pressure. Two types of drain valves are produced: PSK-25 and PSK-50, differing from each other only in dimensions and throughput. Gas from the gas pipeline after the regulator enters the PSK membrane. IF the gas pressure from above is greater than the spring pressure from below, then the membrane moves down, the valve opens and the gas is released into the atmosphere. As soon as the gas pressure becomes less than the spring force, the valve closes. The degree of compression of the spring is adjusted with a screw.

Filters (Fig. 85). Exist Various types filters (mesh type FG, hair, viscine with Raschig rings) which are installed depending on the type of regulator, gas pipeline diameter and gas pressure. The RD is installed near the regulator strainer type FG, okaya RDS and RDUK-hair. At large hydraulic fracturing stations, as well as on high-pressure gas pipelines, viscine filters with Raschig rings are installed.

The most widely used in urban gas supply is the hair filter (see Fig. 85, a). The cassette holder is covered on both sides with a metal mesh, which traps large particles of mechanical impurities. Finer dust settles inside the cassette on compressed horsehair moistened with viscine oil. The cassette filter resists the gas flow, so a certain pressure difference occurs before and after the filter. To measure it, pressure gauges are installed, according to the readings of which the degree of contamination is judged. An increase in the gas pressure drop in the filter to more than 10 kPa (1000 mm water column) is not allowed, as this may cause hair to be carried away from the cassette. To reduce pressure drops, it is recommended to periodically clean the filter cassettes. The internal cavity of the filter should be wiped with a rag soaked in kerosene. The cassettes are cleaned outside the hydraulic fracturing building.

In Fig. 85, b shows the device of a filter intended for hydraulic fracturing. equipped with RDUK regulator. The filter consists of a welded body with connecting pipes for gas inlet and outlet, a cover and a plug. Inside the case there is a mesh cassette filled with horsehair or nylon thread. A metal sheet is welded inside the housing on the gas inlet side, protecting the mesh from direct hit solid particles. Solid particles coming with the gas, hitting the metal sheet, are collected in the lower part of the filter, from where they are periodically removed through the hatch. Remaining in the gas flow particulate matter filtered into a cassette, which can also be read as needed. To clean and rinse the cassette, the top filter cover is removable. To measure the pressure drop that occurs when gas passes through the filter, U-shaped differential pressure gauges are used, connected to special fittings before and after the filter, regardless of the presence of a filter in the hydraulic fracturing equipment set, an additional filter device is installed in front of the rotary meters (see Fig. 85, V).

Control and measuring instruments (instruments). The following instrumentation is installed at gas control points to monitor the operation of equipment and measure gas flow: thermometers for measuring gas temperature, indicating and recording (self-recording) pressure gauges for measuring gas, devices for recording pressure drops on high-speed flow meters (if necessary), consumption metering devices ( consumption) of gas ( gas meters or flow meters).

The gas temperature is measured to introduce corrections when calculating its consumption. If the flow meter is located after the gas pressure regulator, then the thermometer is installed on the section of the gas pipeline between the regulator and the gas flow metering devices. Instrumentation should be located directly at the measuring point or on a special instrument panel. If the instrumentation is mounted on the instrument panel, then for measurement they use one device with switches for measuring readings at several points. To measure gas flow rates up to 2000 m3/h at pressures up to 0.1 MPa (I kgf/cmg), rotary meters are used, and for high flow rates and pressures, measuring diaphragms are used. Impulse tubes from the diaphragms are connected to secondary instruments (ring or float differential pressure gauges).

The installation location of meters and flow meters is chosen taking into account the possibility of conveniently taking their readings and carrying out maintenance and repair work without interrupting the gas supply. Instrumentation is connected to gas pipelines steel pipes. To assemble instrument panels, you can use tubes made of non-ferrous metal. At gas pressure up to 0.1 MPa (1 kgf/cm2), rubber tubes up to 1 m long and 8-20 mm in diameter are used. Impulse tubes are connected by welding or threaded couplings. Instrumentation with electric drive, as well as telephone sets must be explosion-proof. otherwise, they are placed in a room isolated from the GRV or outside in a locked box.

Instruments for measuring gas consumption (flow). These devices are installed in accordance with the “Rules for measuring gas and liquid flow rates using standard devices” RD50-213-80. To account for gas consumption, gas meters and flow meters are installed in the GRG, which keep track of gas in cubic meters under operating conditions (pressure and temperature), and payments to consumers are made under standard conditions (pressure 0.102 MPa; 760 mm Hg and temperature 20 ° C). Therefore, the amount of gas indicated by the instruments is reduced to standard conditions. In small, medium-sized hydraulic fracturing operations, volumetric rotary meters of the PC type are widely used. The currently specified counter counts. The meter consists of a housing, two profiled rotors, a box with gears, a gearbox, a counting mechanism and a differential pressure gauge. Gas enters through the inlet pipe into working chamber, where the rotors are located. Under the influence of the pressure of the flowing gas, the rotors begin to rotate. In this case, a closed space filled with gas is formed between one of them and the chamber wall. Rotating, the rotor pushes gas into the gas pipeline going to the consumer. Each rotation of the rotor is transmitted through gearboxes and a gearbox to the counting mechanism. Counters are installed on vertical sections gas pipelines so that the gas flow is directed through the meter from top to bottom. If necessary, measurements large quantities parallel installation of gas meters is allowed. The PC meter accounting error does not exceed 23%.

The following modifications are available: PC-25; PC-40; RS-100; PC-250; PC-400; RS-600M and RS-1000. The numbers respectively indicate the nominal throughput of the meter in m 3 / h. High-speed flow meters are used to measure the consumption of large quantities of gas. They are installed at large hydraulic fracturing sites and facilities. Flow meters, depending on the adopted measurement method, are divided into those whose operation is based on throttling the gas flow through restricting devices installed on gas pipelines, and flow meters whose operation is based on determining consumption (flow) by the velocity pressure of the gas flow. Flow meters with restriction devices in the form of metal diaphragms (washers) are widely used in the gas industry.

Gas control points are installed near residential and industrial premises. In this article we will look at the purpose, design and classification of hydraulic fracturing. We also provide the basic principles for installing points and requirements for their operation.

Explanation and types of hydraulic fracturing

A gas control point (GRP) is a complex consisting of technological equipment and mechanisms for regulating gas pressure. The main purpose of the installation: reducing the inlet pressure of the natural substance and maintaining a given level at the outlet, regardless of consumption.

Types of hydraulic fracturing regarding the location of equipment installation are:

• GRPSh (cabinet gas control units) - for this type it is envisaged that the corresponding equipment should be placed in special cabinet from fireproof materials;
• GRU (gas control units) - for this type of equipment, it is mounted on a frame and located at the place where gas is used or in another place;
• PGB (gas control block points) - with this placement, the equipment is installed in container-type buildings, one or more;
• GRP (interpretation - stationary gas control points) - with this type of equipment, the equipment is located in specialized buildings or separate rooms; such a device is not accepted as a standard product with full factory readiness.

Classification

Hydraulic fracturing can be classified according to several parameters. For example, if possible, lower the gas pressure. Explanation of hydraulic fracturing is discussed below.

1. Single-stage gas control points. In such systems, the gas pressure from input to operating is regulated in one step.
2. Multi-stage gas control points. In systems with too high pressure, one regulator may not be able to cope with the reduction function. In this case, adjustment occurs in several stages by installing one or more regulators.

Based on the gas output pressure provided by hydraulic fracturing (interpretation: gas control points), installations are distinguished that provide the same or different pressures.

Also, hydraulic fracturing units can have one or two outlets. The design of the device can be left-handed or right-handed, depending on the location of the gas supply.

The entry and exit of the volatile substance can be made from opposite sides of the hydraulic fracturing system; on the one hand, it can be vertical and horizontal.

The gas pressure at the outlet of the point may vary, and hydraulic fracturing is classified as follows:

Hydraulic fracturing reduction lines

The decoding of the hydraulic fracturing has already been given. Points can be dead ends or loops. This scheme is used for the reliability of gas supply. It consists of combining several hydraulic fracturing units. It is believed that what more installations looped, the higher the reliability of the system. A scheme is considered dead-end when it is inappropriate to use more than one hydraulic fracturing unit to supply gas to the consumer.

According to technological schemes of hydraulic fracturing there are distinguished:

1. Single strand items. They are equipped with one gas reduction line.
2. Multi-thread. They can be equipped with two or more gas reduction lines connected in parallel. Such a device is used when trying to achieve maximum reliability and performance parameters of hydraulic fracturing.
3. With bypass. A reserve reduction line, which is used during repairs of the main line.

Regulators in multi-thread installations can be connected in parallel or in series.

The hydraulic fracturing unit is equipped with the following equipment:

• gas pressure reducer;
• gas filter;
• safety fittings;
• shut-off valves;
• instrumentation;
• gas odor substance input unit;
• gas heaters.

Two shut-off devices are installed on the reserve line, between which a pressure gauge is mounted.

Single strand items

Gas control points (interpretation of hydraulic fracturing) with one gas reduction line consist of: technological equipment and the frame on which it is placed.

The operating principle of such devices:

1. The gas passes through the inlet and enters the filter. Here it is cleaned from harmful substances and impurities.
2. Then the gas is supplied to the pressure regulator through a safety shut-off valve, in which the pressure is regulated - reduced to the required parameters, as well as maintaining the values ​​at the required level.

If, when passing through the regulator, the pressure does not decrease to the standard parameters, then a safety relief valve or water seal is provided.

If the gas is not discharged, then the safety shut-off valve is activated and the gas supply to the RN-GRP is stopped (interpretation: pressure parameter at the beginning of the shut-off valve opening) no more than +0.02 MPa - the normatively established valve response value (GOST R 53402-2009 clause 8.8.2.7).

In gas control units, both direct and indirect-acting regulators can be used.

When choosing a hydraulic fracturing unit with one reduction line, they usually rely on the operating parameters of the regulator: throughput, inlet and outlet pressure.

Multi-strand items

Explanation of the abbreviation GRP - gas control points, this has already been said, come with one reduction line, two or more.

Regulators on the gas pressure relief line can be installed either in parallel or in series.

Operating principle of a multi-thread system:

1. One source is used to supply gas.
2. After entry, the gas spreads through all hydraulic fracturing lines.
3. At the output, the lines are combined into one collector.

Multi-line systems are more reliable because if one reduction line fails, its functions can be performed by the others. Similar actions are carried out if technical work is necessary: ​​replacing the regulator, cleaning the filter.

The circuits are used mainly at high-pressure points, for example, to supply industrial consumers. Multi-thread systems are more expensive compared to single-thread analogues, and they have larger dimensions.

Hydraulic fracturing with bypass line

Above we discussed how hydraulic fracturing is deciphered and what types there are. In this paragraph, the last option for organizing a gas control point will be presented - with a bypass.

A bypass is called a bypass, another name is a reserve, reduction line natural gas. It is used when the main one is being repaired.

Multi-strand or single-strand circuits are equipped with a bypass line. It is equipped with the same equipment as the working one, but does not participate in the gas supply process if the main line is working properly.

designed to reduce gas pressure and maintain it within specified limits hydraulic fracturing are located:

• in separate buildings;
• built into one-story industrial buildings or boiler rooms:
• in cabinets on external walls or free-standing supports;
• on coatings industrial buildings I and II degrees of fire resistance with non-flammable insulation;
• in open fenced areas under a canopy

GRU are located:

• in gasified buildings, usually close to the entrance;
• directly on the premises boiler rooms or workshops where gas-using units are located, or in adjacent rooms connected to them by open openings and having at least three air exchanges per hour. Innings gas from GRU to consumers in other separate buildings is not allowed.

Schematic diagram GRP (GRU), purpose of equipment.

Purpose and nature of the equipment used in hydraulic fracturing And GRU identical.

IN GRP (GRU) provide installation: filter, safety shut-off valve PZK, gas pressure regulator, safety relief valve PSK, shut-off valves , instrumentation instrumentation, devices gas consumption metering(if necessary), as well as the device bypass gas pipeline (bypass) with the installation of two shut-off devices in series and a purge pipeline between them in case of equipment repair.

The second shut-off device along the gas flow bypass should provide smooth regulation.

For hydraulic fracturing with an inlet pressure of more than 6 kgf/cm 2 and a throughput capacity of more than 5000 m 3 /h, instead of bypass provide an additional reserve control line.

Installation PZK provide before pressure regulator. PZK created for automatic shutdown gas supply at the hour of increasing or decreasing gas pressure after the regulator above the established limits.

According to the requirements of the regulations, the upper limit of operation PZK should not exceed the maximum operating gas pressure after the regulator by more than 25%. The lower limit set by the project meets the requirements for ensuring sustainable operation gas burner devices, and is specified during commissioning.

Installation PSK must be provided for pressure regulator, and if available flow meter— after the flow meter.

PSK must ensure the release of gas into the atmosphere, based on the conditions of a short-term increase in pressure that does not affect industrial safety and normal work gas equipment consumers.

Before PSK provide disconnecting devices that must be sealed in the open position.

Safety relief valves must ensure gas discharge when the rated operating pressure after the regulator is exceeded by no more than 15%.

Rule requirements for setting the response limit PSK-15% and upper response limit PZK— 25% determine the order (sequence) of valve actuation first PSK,then PZK.

The expediency of this order is obvious: PSK, preventing a further increase in pressure by releasing part of the gas into the atmosphere, does not disrupt the operation of boilers; when triggered PZK boilers turn off abnormally.

Fluctuations in gas pressure at the outlet hydraulic fracturing allowed within 10% of operating pressure. Malfunctions of regulators causing an increase or decrease in operating pressure, malfunctions safety valves , as well as gas leaks must be eliminated in an emergency manner.

Getting started pressure regulator in the event of a gas supply interruption, it must be carried out after identifying the reason for the operation of the safety shut-off valve PZK and taking corrective action.

IN hydraulic fracturing purge and discharge pipelines should be provided that lead outside to places that provide safe conditions for gas dispersion, but not less than 1 m above the eaves or parapet of the building.

It is allowed to combine purge pipelines of the same pressure into a common purge pipeline. The same requirements apply when combining waste pipelines.

IN hydraulic fracturing install indicating and recording instrumentation instrumentation(12) to measure inlet and outlet pressure and gas temperature. If gas consumption is not recorded, it is permissible not to provide a recording device for measuring gas temperature.

The accuracy class of pressure gauges must be at least 1.5.

A three-way valve or similar device must be installed in front of each pressure gauge to check and disconnect the pressure gauge.

Gas filters.

Used for gas purification mesh, hair, cassette welded filters and viscine dust collectors.

Choice filter determined by capacity and inlet pressure. Hair filters are given FV And F1.

In filters like FV Gas purification occurs in a cassette made of wire mesh filled with horsehair or nylon thread. The filter material, which must be homogeneous, without lumps or strands, is impregnated with viscine oil (a mixture of 60% cylinder oil and 40% solar oil).

The end parts of the cassette are covered with wire mesh. A perforated metal sheet is installed on the outlet side of the cassette, protecting the rear (along the gas flow) mesh from rupture and carryover of the filter material.

Filters FG intended for GRP (GRU) with gas flow from 7 to 100 thousand m 3 /h. Frame filter steel welded.

The peculiarity of this filter is the presence free space and a bumper sheet. Large particles entering filter, hit the sheet, lose speed and fall to the bottom, and the small ones are caught in a cassette filled with filter material. The pressure drop across the cassette should not exceed the value established by the manufacturer.

Safety shut-off valves.

Safety shut-off valve type PKN (B) consists of a cast iron body of 1 valve type, a membrane chamber, a superstructure head and a lever system. Inside the body there is a seat and a valve 9. The valve stem is connected to a lever 14, one end of which is hinged inside the body, and the other with a load is brought out. To open valve 9 using lever 14, the rod is first raised slightly and held in this position, this opens a hole in the valve and the pressure difference before and after it decreases. The lever with the load 14 is brought into engagement with the anchor lever 15, which is hinged on the body. The impact hammer 17 is also hinged and located above the arm of the anchor lever. Above the body, under the superstructure head, there is a membrane chamber into which gas is supplied from the working gas pipeline under the membrane. On the top of the membrane there is a rod with a socket into which the rocker arm 16 fits with one arm. The other arm of the rocker arm engages with the pin of the impact hammer.

Diagram of safety shut-off valve type PKN (B)

1 - body; 2 - adapter flange; 3 - cover; 4 - membrane; 5 - large spring; 6 - plug; 7 - small spring; 8 — rod; 9 - valve; 10 — guide post; 11 - plate; 12 - fork; 13 - rotary shaft; 14 — lever; 15 — anchor lever; 16 — rocker arm; 17 - hammer

If the pressure in the working gas pipeline exceeds the upper or decreases below the lower specified limits, the membrane moves the rod, disengaging the impact hammer with the rocker arm, the hammer falls, hits the shoulder of the anchor lever, disengaging its other arm from engagement with the valve lever. The valve lowers under the influence of the load and closes the gas supply. The organ for adjusting the PKN (B) to the upper limit is a large superstructure spring.

When the gas pressure in the submembrane cavity increases or decreases beyond the setting, the tip moves to the left or right and the stop mounted on the lever disengages from the tip, releases the interconnected levers and allows the axis to rotate under the influence of the springs. The valve closes the gas passage.

Pressure regulators.

Universal pressure regulator Kazantseva RDUK-2 consists of the regulator itself and the control regulator - the pilot.

City (inlet) pressure gas through filter 4 through tube A enters the pilot space above the valve. With its pressure, the gas presses the plungers of regulator I and pilot 5 to seats 2 and b; there is no pressure in the working gas pipeline. Slowly and smoothly screw in the pilot glass 10.

The pressure of the compressed spring 9 overcomes the gas pressure in the over-valve space of the pilot and the force of spring 7 - the pilot valve opens and gas from the over-valve space of the pilot enters the sub-valve space and then through connecting tube B through throttle d1, under the regulator membrane 3. Part of the gas through throttle d is discharged into working gas pipeline. Due to the continuous movement of gas through the throttle, the pressure under the regulator membrane is slightly greater than the pressure in the outlet gas pipeline.

Under the influence of a pressure difference, membrane 3 rises, slightly opening regulator valve 1 - the gas goes to the consumer. We screw in the pilot glass until the pressure in the outlet gas pipeline becomes equal to the specified operating pressure.

When the consumer's gas flow changes, the pressure in the working gas pipeline changes, thanks to the impulse tube B, the pressure above the pilot membrane 8 changes, which lowers and, compressing the spring 9, or rising under the influence of the spring, closes or slightly opens, respectively, the pilot valve 5. At the same time, it decreases or the gas supply through tube B under the pressure regulator membrane increases.

For example, when the gas flow rate decreases, the pressure increases, the pilot valve 5 closes and the regulator valve 1 also closes, restoring the pressure in the working gas pipeline to the set value.

With increasing flow and decreasing pressure valve the pilot and regulator open slightly, the pressure in the working gas pipeline rises to the set value. Block pressure regulator Kazantseva RDBK consists of three units: regulator 1; stabilizer 2; pilot 3.

The control valve is similar in design to the valve RDUK and is distinguished by the presence of a pulse column 4 with three control chokes.

Safety relief valves.

Safety-reset devices must ensure full opening when the specified maximum operating pressure is exceeded by no more than 15%. After releasing the excess gas volume and restoring the design pressure, the relief device must close quickly and tightly. The most widely used spring relief valves are the type PSK. The valve consists of a body 1, a membrane 2 on which the valve 4 is mounted, an adjustment spring 5 and an adjusting screw 6. The valve communicates with the working gas pipeline through a side pipe. When the gas pressure increases above a certain value by compressing the tuning spring 5, the membrane 2 together with the valve 4 opens, allowing the gas to escape through the relief plug into the atmosphere. When the pressure decreases valve under the action of the spring it closes the seat, the gas discharge stops.

Safety relief valve installed behind the regulator, if there is a flow meter - behind it. Before PSK a disconnecting device is installed, which must be sealed in the open position.

Spring PSK must be equipped with a device for their forced opening. On low-pressure gas pipelines, it is allowed to install a PSK without a device for forced opening.

Cabinet control point.

Cabinet control point (SRP) a cabinet-mounted technological device designed to reduce gas pressure and maintain it at a given level. Installed for gas supply to low-power consumers, isolated from the general system.

Price ShRP significantly lower compared to hydraulic fracturing. ShRP as well as GRP, GRU must include:

• locking devices before and after installation;
• filter;
• safety shut-off valve;
• safety relief valve;
• pressure regulator;
• pressure gauges at the inlet, outlet, before and after the filter;
• bypass line (bypass) with two disconnecting devices on it ShRP can be supplied with a heat-insulating coating internal surfaces walls, with or without heating.

Instrumentation in GRP (GRU).

Indicating and recording instruments are installed to measure inlet and outlet pressure and gas temperature instrumentation with an electrical output signal and electrical equipment must be explosion-proof; in the normal version they are placed outside or in a separate room hydraulic fracturing, attached to a fire-resistant gas-tight wall. The impulse line inputs pass through a sealing device.

Gas metering devices are installed if necessary.

The accuracy class of pressure gauges must be at least 1.5. A three-way valve or similar device must be installed in front of each pressure gauge to check and disconnect the pressure gauge.

Requirements for hydraulic fracturing premises.

Building hydraulic fracturing must belong to the I and II degrees of fire resistance class CO, be one-story, without a basement, with a combined roof.

Accommodation allowed hydraulic fracturing built into one-story gasified industrial buildings, boiler rooms, attached to gasified industrial buildings, domestic buildings for industrial purposes, on the coatings of gasified industrial buildings of I and II degrees of fire resistance class CO, with non-flammable insulation and in open fenced areas, as well as in containers GRPB.

Buildings to which it is allowed to attach and build in hydraulic fracturing, must be at least II degree of fire resistance class CO with premises of categories G and D. Building structures of buildings (within the adjoining hydraulic fracturing) must be fire-resistant type I, gas-tight.

Building hydraulic fracturing must have a covering (combined roof) lightweight design weighing no more than 70 kg/m2 (subject to snow removal in winter).

The use of coatings from structures weighing more than 70 kg/m2 is allowed when constructing window openings, skylights or easily removable panels with a total area of ​​at least 500 cm 2 per 1 m 3 of the internal volume of the room.

Premises in which gas control units are located GRU, as well as free-standing and attached hydraulic fracturing And GRPB must meet the requirements for premises of category A.

The material of the floors, the arrangement of windows and doors in the regulatory rooms must prevent the formation of sparks.

Walls and partitions separating rooms of category A from other rooms should be fire-resistant type I, gas-tight, and they should rest on the foundation. Seams of walls and foundations of all premises hydraulic fracturing must be bandaged. Brick dividing walls should be plastered on both sides.

Auxiliary premises must have an independent exit to the outside of the building, not connected to the technological room. Doors hydraulic fracturing should be fireproof, opening outwards.

Installation of smoke and ventilation ducts in dividing walls ( internal partitions), as well as in the walls of the building to which it is attached (within the adjacency) hydraulic fracturing, not allowed.

The need for space heating hydraulic fracturing should be determined depending on climatic conditions.

Indoors GTR natural and/or artificial lighting and natural constant ventilation, providing at least three air exchanges per hour.

For rooms with a volume of more than 200 m3, air exchange is carried out according to calculation, but not less than one air exchange per hour.

The placement of equipment, gas pipelines, fittings and instruments should ensure their convenient maintenance and repair.

The width of the main passage in the premises must be at least 0.8 m.

Indoor fire extinguishing agents hydraulic fracturing.

1. Powder fire extinguisher 10 l with charge BC (E) for an area of ​​up to 200 m 2. Can be used carbon dioxide fire extinguishers in appropriate quantities.

2. A box of sand with a volume of at least 0.5 m3.

3. Shovel.

4. Asbestos sheet or felt 2x2 m.

Putting it into operation.

Start GRP (GRU) is gas hazardous work and is carried out according to a work permit or in accordance with production instructions. The work is performed by a team of workers consisting of at least two people under the guidance of a specialist.

1. Check the absence of gas contamination in the room hydraulic fracturing.

2. Check that the requirements for equipment and premises are met. All shut-off devices, except for the valves on the purge gas pipelines and on the discharge gas pipeline in front of PSK, must be closed, PZK closed, the regulator pilot is unloaded.

3. If there is a front Hydraulic fracturing (TRU) plug, remove it.

When preparing for start-up, the opening of the shut-off devices is carried out “from end to beginning”, against the gas flow. Let the gas flow through the main line, for which:

• ensure the gas flow of the last unit along the gas flow;
• open the shutdown device at the entrance to the boiler room and the outlet on the main line;
• pilot RDUK unloaded;
• open PZK to pass;
• ensure the operation of the pressure gauge on the filter by opening the tap (valve) on the impulse line to the filter;
• slowly open the first disconnect device;
• blow out the gas pipeline and close the tap on the spark plug;
• by slowly screwing in the pilot glass, ensure the required operating pressure (the valves on the impulse lines of the regulator are open);
• after starting the first unit, open the valve on the impulse line of the shut-off valve and cock the impact hammer;
• check the tightness of connections of gas pipelines and fittings.

4. Close the permit and make an entry in the journal.