The most common locking devices include valves and taps. What is the specificity of both?
What is a valve?
Under valve It is customary to understand a shut-off mechanism on a pipeline, which involves blocking the flow of liquid or gas through a partition. It can move across the pipe up and down or left and right. In many cases, the valve also allows you to regulate the intensity of the flow of liquid or gas. For example, if the valve partition is moved halfway, the flow intensity is reduced by 50%. As it moves higher or to the left (or lower or to the right - depending on its initial position), the intensity of the flow can increase or decrease.
The partition on the valve is most often made in the form of a disk, sometimes a wedge or a sheet. There are valves in which the partition consists of one element, but in some cases it is represented by several parts. For example, if there are two of them, increasing the intensity, or opening the flow, can be accomplished by moving them apart. Reducing dynamics, or closing the flow, on the contrary, is carried out by closing components valve partitions.
The main advantage of the valve is the ability to open or close the flow relatively quickly and with relatively low energy costs (or set its desired intensity).
Valves can be installed on pipelines with high pressure - for example, heating, water supply. They are among the most airtight locking elements.
With frequent use, a valve can wear out quite quickly - this is due, in many cases, to a fairly large friction force between the edges of the partition and the block in which it moves left and right or up and down.
Another disadvantage of the valve is the need to isolate extra space outside the pipeline cross-section for the purpose of temporary placement of the moving part of the partition. Installation, maintenance and repair of the locking element in question can also require quite a lot of labor.
Thus, taking into account the noted advantages and disadvantages, the valve is most often used not as an adjustment element, but as a locking element, which is supposed to be placed in the “open”, “closed” or other static position for quite a long time. In order to frequently regulate the flow of liquid or gas in pipelines, another shut-off device - a tap - can be successfully used. Let's consider its features.
What is a faucet?
Tap- this is a locking element, the main part of which is a shutter, presented in the shape of a ball, in the form of a cone or a cylinder. They have a channel with a diameter that is sufficient to ensure the passage of flow if the corresponding channel is located parallel to the flow or is located under small angle to him. In turn, when the channel is placed perpendicular to the flow (by rotating the ball, cone or cylinder in which it is made) or at a large angle to the flow, the movement of liquid or gas in the pipe stops or its intensity decreases.
Changing the position of the valve is carried out by rotating a spherical, cone-shaped or cylindrical valve around its axis perpendicularly or parallel to the flow (this is not important, the main thing is to achieve the necessary tightness).
The faucet, like the valve, is characterized high degree tightness. Therefore, it can be installed on pipelines with high pressure. At the same time, cranes are not characterized by the main disadvantage of valves - wear. Provided that the locking device in question is properly lubricated and maintained, it can last a long time.
The valve is thus excellent for regulating the rate of movement of liquid or gas in a high-pressure pipe. This explains its frequent use as a locking mechanism at the final section of pipelines. For example, as the main element household faucets, which are located in bathrooms, kitchens, showers.
The valve, as a rule, does not require a large space outside the pipeline cross-section, since its main element - the valve - rotates around its axis within the pipe. True, it may be necessary extra bed for the control valve and other mechanisms that complement it.
Comparison
The main difference between a valve and a faucet is that the main element of the first locking device is a partition that moves perpendicular to the flow of liquid or gas in a pipeline. The main element of the faucet is a valve with a channel made in it, which, when placed parallel to the flow or at a slight angle to it, increases the intensity of fluid movement in the pipe, and when placed perpendicular to the flow or at a large angle to it, reduces its intensity.
The difference between the considered types of locking elements can also be traced in the following aspect:
- wear;
- requirements for spaces outside the pipeline cross-section;
- scope of application, prevalence of inclusion in the structure of household faucets.
Having determined what the difference is between a valve and a faucet, we will record the conclusions in a small table.
Table
| Gate valve | Tap |
| What do they have in common? | |
| Gate valves and taps provide high tightness to block the flow of liquid or gas in a pipeline, suitable for high pressure pipes | |
| What is the difference between them? | |
| The main locking element of the valve is a partition that moves left-right or up-down (unless it is represented by a more complex - for example, double-leaf design) | The main shut-off element of a faucet is a valve that can rotate around its axis and place the channel made in it at a greater or lesser angle relative to the flow of liquid or gas in the pipe |
| Wears more intensely with frequent use | Less wear and tear with frequent use |
| As a rule, it requires significant spaces outside the pipeline cross-section to accommodate the extending part of the partition | Requires spaces outside the pipeline only for the purpose of placing control elements - valves and their complementary mechanisms |
| It is mainly used as a typical locking element that is in the “open”, “closed” or other static position for a long time | It is used as an adjusting element, through which you can opportune moment set the desired flow rate in the pipeline |
| Generally not used as a component of household faucets | Is one of the main components in household faucets |
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Ball valves: characteristics and use
Ball valves unique in their own way design solution. This is a practical modification of a plug tap. It got its name due to the fact that the cork located in its body is shaped like a ball. Ball valves are designed for flow control various types working environments Its closing and opening is carried out by turning the handle one-fourth of a turn, which achieves a significant simplification of operation when compared with other types of valves.
When the valve is in the “open” position, the ball hole is parallel to the flow line, which ensures direct flow with a low degree of friction and minimal losses pressure.
Ball valves are designed specifically for use in the oil and gas industry. They are practical for pipelines with medium pressure and temperatures not exceeding 200 degrees. Ball valves are not required high costs in production, when compared with other types of valves. And the tightness when using them is also much higher.
Ball valves made of steel are considered more universal, as they have the ability to perform their function even in the presence of low temperature regime And high pressure.
The following types of ball valves can be distinguished. These are valves made of brass and ball valves made of steel. Brass ball valves are successfully used in the construction industry and housing and communal services. In addition to aqueous working media, they are also suitable for low concentration glycol solutions, alcohol, gas and liquid petroleum products. Ball valves made of brass have a minimum size of 15 millimeters, a maximum of 80.
Ball valves made of steel are considered more universal, as they have the ability to perform their function even in the presence of low temperatures and high pressures. The minimum nominal diameter of a steel ball valve is the same as that of a brass valve, but the maximum reaches 500 mm.
No heating system in the modern construction industry is complete without a ball valve design. Ball valves come in both coupling, union and flange types. Ball flanged valves, or rather their design uses flanges as elements connecting the valve and the pipeline.
TO obvious advantages characteristics that flanged ball valves have include:
- low degree of hydraulic resistance;
- various areas of use;
- easy installation and operation.
Taps, various valves and other shut-off valves are necessary element any pipeline and are used in various branches of modern industry.
This article talks about wedge flanged valves, their characteristics, operating principles, and most importantly, the use of these products on different pipelines:
Wedge flanged valves are in demand in communications industrial production on water, oil, and gas pipelines. They are an indispensable part of any pipeline where it is necessary to block a section or the entire pipe. These elements shut-off valves are not complex in design, they have a long service life (up to 50 years). For safe operation pipeline, they are installed at a certain distance from each other so that the pipe can be quickly shut off in the event of an accident or repair.
Flanged valves
Depending on the type of pipeline, appropriate shut-off valves are used. It is obvious that the range of valves used here is wide. Flange valves found wide application in all spheres of the national economy:
- In the heating system;
- In the transport industry when transporting petroleum products;
- In energy communication pipelines;
- In shipping company pipelines.
Flange valve devices
Despite their simplicity, flanged wedge gate valves are highly effective among shut-off valves. Depending on the locking element, the type of wedge valve is determined. The flanged valve got its name because of its design: on its sides there are flanged disks that mate with the same disks on the pipe.
For flanges on the valve and on the pipe, the diameter and holes must strictly match, otherwise they cannot be connected. A gasket made of paronite, rubber or a rubber ring must be installed between the flanges, depending on the environment inside the pipe. This design of the wedge valve makes it quick-removable, which is important during repairs.
According to the design of the nut, wedge products are divided into 2 categories: with a retractable and fixed nut.
That is, in the first option, when opening or closing the valve, the nut moves progressively. In the second option, the nut remains in place and the screw moves out. In the second category, wedge valves occupy less space and they are used when moving petroleum products and other liquids that do not cause metal corrosion. Wedge products with a sliding nut are mainly used.
According to the closing method, devices are divided into valves:
- WITH manual control. Closing is done manually using a handle or valve;
- WITH automated control. With this type of closing, mainly electric motors with gearboxes are used, and they are turned on via a remote control by the operator. Hydraulic and pneumatic drives are used less frequently, due to the additional supply of pipes, instruments, etc.
Design features and application of valves
In addition, devices are divided according to their design. There are ball, gate and wedge valves. The latter are the most popular and in demand in the line of shut-off valves.
Flanged valves are manufactured in two versions: wedge and parallel devices.
Flanged Wedge Gate Valves
With wedge flange devices, the locking mechanism moves at an angle of 90 degrees to the flow. The sealing gaskets in them are installed at a certain angle to each other. Typically, such valves are used when moving water, gas, and oil products in pipes. The wedge itself can be solid, metal with rubber coating or made from two hard drives made of alloy steel. As a result of this assembly, it is possible to change the stuffing box without blocking the pipe. However, when using such products, sometimes the locking device jams due to temperature differences or damage to the gasket.
Clinket valve
The clinket valve has 2 disks inside, rigidly connected to each other. This design is reliable, it does not jam when moving, rubber gaskets wear minimally, and the valve is much easier to operate. Such valves are most common in pipelines on ships, due to harmful effects sea salt.
With parallel design, the surfaces are parallel to each other. They are also divided into valves: single-disc (gate); double disc valves.
Gate valves
Gate valves are used when the medium is directed in one direction. Due to their simple configuration, they cannot hermetically provide maximum overlap, but they are repairable. This makes it possible to use them in environments where mechanical particles are present, namely in sewer systems.
Wedge valves with ball locking mechanism
Devices with a ball mechanism are similar in design to household taps. The most popular models are DN50 due to their low cost. DN100 products are equipped with technological discs, which are pressed by springs and are used more in the gas industry.
Hose-type flanged devices
Hose-type valves are fundamentally different from their counterparts: they do not have seat seats. The liquid circulates through the hose, which, if necessary, is clamped with a shutter. Such device designs are used when the moving medium is aggressive and needs to be completely isolated from the valve body to avoid corrosion. Similar products are used in the chemical industry to move aggressive liquids during high temperature about 100 degrees and pressure up to 1.6 MPa.
Advantages and disadvantages of wedge valves
Among the main advantages, it is worth highlighting:
- Quick release connection. This makes it possible to quickly replace the device;
- The service life without repair reaches 50 years;
- Simplicity of design;
- Reliability of constipation;
- Slight effort when closing. The movement of the wedge-shaped disk occurs due to the rotation of the screw by the steering wheel.
The products also have flaws, the main one is the large overall height of the device. This especially applies to valves with a rising stem. After all, in them the screw stroke should be equal to the height of the valve itself. Another disadvantage is the wear of rubber seals, which occurs as a result of prolonged opening of the product valve. And thirdly, when opening manually, it takes a lot of time to fully extend the locking device.
Valves and gate valves are the two main elements most often used in industrial pipelines. Without them, it is difficult to imagine any supply system of more or less large size.
The purpose of such equipment is simple - to give a person the ability to control the movement and state of the transported liquid inside the pipes.
Many people unknowingly confuse valves and gate valves. Some say that there is no difference between them, while others, on the contrary, attribute non-existent properties to each instrument.
The truth, as always, is in the middle. Valves and gate valves are indeed different from each other, but they also have similarities. This article will describe their detailed comparison.
Contents of the article
Features and purpose
A valve or gate valve is a locking system. According to the standard, they are called shut-off valves.
You've probably already encountered shut-off valves. For example, for any household system water supplies are probably worth limiting the flow of liquid in one direction or another. Completely closing the tap in a matter of seconds blocks the movement of the carrier, cutting off a specific section of the branch.
As a result, with one movement of your hand you get the opportunity to isolate a part of the pipeline and then perform some operations on it.
IN living conditions valves are most often used. Valves and gate valves are also shut-off valves, only of a larger type.
Placed on pipes with a diameter of up to 100 mm. The parts described in this article are too large and powerful. They can be mounted on pipes whose diameter only starts from 100 mm (although there are exceptions).
Mostly this means installation on main branches of water supply systems, heating systems, oil pipelines, oil pipelines, etc.
Interestingly, it is designed so that each element can withstand enormous pressure under conditions of constant movement of the carrier. Because of this, the design is more expensive, but much more efficient than conventional valve fittings.
Connection type
We have already noted that a valve, like a gate valve, has a similar structure and is used for similar tasks. To compare them with each other, and also to have a complete picture in your head of how a valve differs from a gate valve, you need to analyze the operating principle of each sample. Understand how it works and what it consists of.
But before that, let’s pay attention to the methods of connecting them to the pipeline. They have them in common.
Elements of this type can be:
- welded;
- coupling
This refers to the type of connection to the pipeline. There are practically no differences here. Both valves and gate valves are made in all variations.
The flange type of connection implies. A kind of connecting rings welded onto the edges of both shut-off valves and pipelines. This good option when you need reliability combined with practicality.
The flanges are welded onto the outlets, then... The connection occurs by tightening the mating flanges on the pipe and the valve with bolts. The number of bolts, their size, flange diameter and many other parameters depend on the conditions in each specific case.
Flanges are most conveniently used in industry, but also in domestic conditions, as well as in civil engineering they are useful.
I think you already know enough about welded joints. Welded shut-off valves are not as popular as flanged or coupling valves, but they are also quite widely represented on the market, which means it would be a mistake not to mention them.
Mounted on pipelines by welding gas or electric welding. The advantages of such connections are their strength. Disadvantages: it is not possible to remove the shut-off valves. And such a need can arise at any moment.
Shut-off valves do not last forever. Dynamic processes are constantly taking place in it. The seals wear out, the wedge becomes loose, parts wear off. Sooner or later the valve will fail. And what to do then is an open question.
Mounted primarily on threaded connections. This is an intermediate option between welding and flanges. You need to tinker with it more, but you can do without it altogether welding machine. They are used to a greater extent on medium-sized civilian systems.
Valve design and operating principle
Valve - shut-off valve. You should have seen the valves, if not live, then on TV.
This is a large pipeline element, slightly thicker and with a large control ring, which is actually called a valve. The function of the valve is to shut off and regulate the flow of liquid inside the pipe.
This is how it differs from a gate valve. The fact is that the fixed part can be in several positions at once.
If you twist it a few turns, the flow is only partially blocked. The locking element will artificially reduce the diameter of the passage hole inside, which will affect the amount of liquid delivered.
Closing the valve completely shuts down the entire system, just as it does. This ability to choose the position for the shut-off element inside the valve is its main advantage.
Very often in industrial pipelines there is a need not only to completely shut off the flow of liquid, but only to moderate it to certain values. The easiest way to do this is by installing valves in potentially suitable places. More convenient and simple way humanity hasn't figured it out yet.
Parsing the insides
The valve consists of several main parts. The base for all its internals is contained in a powerful body.
The body is predominantly cast, rather than collapsible. But there are different models, each specific circuit undergoes some changes, in accordance with the expectations and desires of the manufacturer.
There is a hole inside the case for the passage of liquid. This hole can be either full-size or reduced.
The full-size passage makes it possible to transport the liquid in full, and also reduces the load on the inside of the valve. The liquid flows without problems, meeting no resistance.
Another thing is miniature valves. They in their basic state are not capable of passing a nominal amount of media in the same period of time.
In the central part of the body there is a valve blocker or simply a valve with a spindle. A thread with guides is connected to it, and the thread is controlled by rotating the valve handle.
The system is simple and unpretentious, which is why it is so effective. By rotating the handle, we transfer force to the screw thread. It affects the position of the valve inside the valve. Tightening the handle lowers the valve, unscrewing it on the contrary raises it. Accordingly, you can regulate the movement of the carrier in the pipe as you wish.
An important feature is that the flow of liquid in the valve is blocked by parallel blocking of the flow. This affects the cost of the entire structure, as well as its price of its varieties. That is why a full bore valve sample is much more expensive than a standard narrowed one.
Gate valve design and operation
The difference between a gate valve and a valve consists of several small, but still extremely important design features. Once you understand them, you will understand exactly what is here and how it works.
A gate valve performs the same tasks as a valve. She is also capable of blocking or opening the system at any time.
Only the valve exists in two positions:
- open;
- closed
There is no third option. Its very design simply does not allow it to effectively partially block the flow. The locking element inside is designed according to this design for a reason.
B is in a position perpendicular to the carrier. It closes in exactly the same way, moving only a few tens of centimeters down.
This simplifies the design, makes it more unpretentious and cheaper. But it also increases pressure on all component parts. Especially if we're talking about o mounted on high pressure pipelines.
Installation of a huge industrial valve (video)
Assembly diagram
In many ways, the gate valve repeats the design of the valve. It also consists of a one-piece cast body. It can also be either full bore or standard, with a narrowed diameter.
The main differences relate to the locking element itself. IN . Closed position the wedge hides it in the upper saddle part. The wedge does not in any way impede the movement of fluid in the system.
A thread is connected to its guides, and it is controlled by rotating the handle. In general, the system is the same as with the valve. The difference lies in the details.
When the handle is rotated, the wedge is simply released, blocking the entire pipe in one moment. The lower part of the wedge fits into the inner seats, sealed with rubber.
Main differences
Let us list all the differences between valves and gate valves. This will make it easier for you to navigate and make your choice.
List of differences:
- The valve can be used to regulate the flow in the system, while the valve has two states: open and closed.
- The valve is blocking the system in parallel; the valve is blocked perpendicular to the flow.
- The valve wears out faster.
- The valve is more expensive, especially its full bore version.
In water and gas pipelines you cannot do without a device called a valve. A valve is a device designed to shut off the supply of various liquids and gases. However, shutting off the water supply is not the main purpose of the product in question. It can also be used to regulate the pressure of water or gas supply through a pipeline, and can also be used as a safety device and condensate drain.
Device design
The valve design is quite simple, and the product consists of the following main parts:
- Frame.
- Locking device.
- Handwheel or locking handle.
The body of the product is made by casting. A locking device is installed inside the housing, and the flywheel is brought out. The body also has threads on both sides, through which the valve is connected to the water supply or gas pipeline. The cross-sectional diagram of shut-off valves is as follows:
Product classification
The water valve is classified according to a number of different characteristics, which include:
- Type and design of the locking device.
- Material of manufacture.
- Features of connection with water or gas pipelines.
Based on the type and design of the locking device, valves are divided into the following types:
- Valve
- Cork or cone.
- Ball.
Let's find out the main features of each type of valve, and also determine their purpose.
Valve devices
The valve valve is also called a valve tap, since the body of the product is divided into two parts by horizontal and inclined partitions. The design of the product with an inclined partition has a hole that has a groove for the valve. This hole is called a saddle.
The valve is part of the rod, which is located at the bottom of the product. An elastic gasket is inserted into the design of the product, resting against the saddle. By means of this stop in the seat, the supply of fluid flowing through the device is blocked. At the top, the rod is equipped with a thread that connects to the threaded connection of the seat nut. With this threaded connection the valve is raised and lowered, thereby shutting off and regulating the pressure of the supply fluid.
Products of this type have advantages and disadvantages. The advantages include:
- Withstand high pressure.
- Adjustment of water volume and pressure.
- Easy to operate.
- If the locking device fails, it can be replaced.
The disadvantages of such a device are:
- High rate of abrasion of the gasket, since with frequent opening and closing of the device, contact of rubber with metal occurs.
- Relatively short service life.
- To completely shut off the liquid supply, you need to rotate the flywheel for a long time.
Cone type product
A cone valve is a type of valve product. The differences between the two devices lie in the design of the locking mechanism. If in the previous version the locking mechanism is presented in the form of a partition, then in this design the device has a plug in the form of a cone. When the rod rotates, it lowers shut-off valve into the opening of the partition, thereby stopping the flow of liquid.
The advantages and disadvantages of this type of product are similar to those of a valve type valve. The cone valve has the following structure as shown below.
Ball type device
The operating principle of this type of valve is completely different from the functioning of previous options. If previous products provide shutoff of water perpendicular to the pipeline, then with a ball-type device everything is different.
The main locking device is a ball, which has a through slot proportional to the fluid flow. Shutting off the liquid supply is ensured by moving the ball with the slot to a perpendicular position. Such valves are also called gate valves.
The advantages of such products include:
- Simplicity of design, which allows the device to be used for a long time.
- Tightness of the structure. Only the stop ball is in contact with water, which also affects long term product services.
- Shutting off and opening the liquid supply is done by turning the handle 90 degrees or half a turn. Due to the rapid shut-off of the liquid supply, such devices are also called reversible floors.
As practice shows, the quality of valve production plays a significant role in the service life. Water valves European production have a service life of up to 10 years, while cheap Chinese analogues fail after a few years.
The disadvantages of the types of valves under consideration include:
- Inability to repair a water supply ball valve. In Chinese products, the integrity of the connection between the handle and the locking ball is compromised. This causes the handle to continue to rotate and the ball to remain in place in a stuck position.
- Inability to regulate fluid flow. It is possible to regulate the flow of liquid using such a product, but in this case the manufacturers do not guarantee the long service life of the device.
What is the difference between a valve and a faucet?
The difference is not in the type of valves, as many people, even plumbers, are accustomed to thinking. Taps and valves are different, although they are often called by the same name. This difference lies in the design of the housing. If the valve is intended to be installed at the junction of two pipes in order to, if necessary, shut off the liquid supply, then the tap is located at the end of the pipeline. A tap is a kind of limit switch that serves to supply water when the need arises.
Now you need to find out what is the difference between a valve and a gate valve. Many people believe that there is no difference between a valve and a valve, however, this is not true. What a valve is and why it is needed is already known. Now let's analyze the valve to find out its main differences from the valve.
The valve performs similar tasks as the devices discussed in the material. However, the valve is not able to regulate the flow rate, so it only closes and opens the flow. The valve cannot regulate the liquid pressure due to its design features. The damper in such a device moves only up and down. The difference between a gate valve and a valve can be seen clearly in the photo below.
What are locking devices made of?
Before you find out what valves are made of, you need to divide them into two types:
- installed in internal water supply networks;
- mounted on external water and gas pipelines.
If the product is intended for internal networks water supply, then devices made of brass, bronze, stainless steel and plastic. If the products are used for outdoor work, then the above materials are used, as well as additionally steel and cast iron.
- Plumbing fixtures made of brass and bronze are expensive options. However, their cost is justified by their quality and durability. Such devices have light weight, small dimensions, and can also be installed not only on the water supply system for supplying cold water, but also hot. Such products are also used in heating systems, since scale does not settle on their surfaces.
- Stainless steel valves. Another good option that has a long service life. They are several times cheaper than brass and bronze devices.
- Plastic products are among the cheapest, but they are in no way inferior in quality to the above models. Their disadvantage is that they can only be installed in plastic pipelines.
Cast iron and steel valves are popular for installation on external pipelines. For the manufacture of such products, cast iron and steel are used, which will significantly reduce the price of the device. After all, similar products made of brass and bronze will cost tens of times more.
Connecting devices to pipes
Valves are divided into two types according to the installation method:
- Coupled and threaded. Main connecting element with this connection method it is a thread. It can be internal and external on the valve (popularly called “mother-father”). Fittings of this type are installed in pipelines with a pressure of no more than 1.6 MPa.
- Flanged. At the end parts of the pipes there are flanges, with the help of which cast iron or steel products are connected. Installation of such devices is carried out on main and industrial pipelines in which the water pressure exceeds 10 MPa.
Plastic valves are connected to pipelines through special welding. Knowing the features of the devices in question, you can select best option for appropriate installation. IN lately are widely popular ball valves, which have a long service life, despite the inability to repair them.