Any pipeline is not complete without special fittings. It is designed to open and close the flow of the working medium (liquid, gas, powdery substances). It can also be used to regulate temperature, pressure, flow. According to their purpose, such types of valves are distinguished as control, drive, safety and shut-off valves. All devices also differ in design. Consider and compare ball valves with check valves.
The first step is to clearly define each of the devices. A crane is a drive valve with a shutter element rotating perpendicular to the working medium. The simplest crane consists of two components - a body and a plug moving around its axis. A shut-off valve is a type of fitting in which the shut-off element moves in the direction of the working medium, while dropping into the seat. It consists of a body, a spindle, a yoke assembly and a spool.
Today, both shut-off valves and ball valves are almost universal and can be used in any conditions. Still, there are fundamental differences between these two devices. Each of them has certain advantages in a specific application. The first and main difference is the more complex design. shut-off valve compared with ball valve... It can also work in a partially open position. The valve can control the flow, which is not possible with the valve application.
Such features directly depend on the design of the devices. Ball valves are equipped with a spherical shut-off element, which changes the pressure when not fully rotated, and the valves are equipped with a ground axle box, the stem which is unscrewed and twisted. Thus, in latest system the valve, when raised or lowered, shuts off or opens the flow of the working medium. The most suitable application of a shut-off valve is in systems with manual flow control. But in comparison with a ball valve, large head losses occur in it, and the flow moves in only one direction, which leads to a breakage of the spool. Shut-off valves characterized by more complex design and less operational reliability. They are also somewhat cheaper than other types of locking fittings, the seals in them wear out more slowly. Ball Valves in turn, they can be used longer without emergencies.
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Shut-off valves are used in the installation of gas supply and sewerage systems. Such devices are visible on different types pipes, their direct purpose is to block any streams (water or gas). The valve and the valve belong to the main mechanisms of this type.
Based on the characteristics of these mechanisms, it is selected certain type devices. To make the right choice, you need to know what works and how.
What is the difference between a tap and a valve?
The main difference is the purpose of the work, their functions. The main task of the valve is to ensure the process of smooth regulation of the gas pressure due to its design features. Of course, a crane is also capable of performing such work, it has the ability to regulate the flow of liquids and gases, but due to the special conditions of use, incomplete overlap is strictly prohibited.
It must be said that neither the valve nor the valve can change the direction of flows, they are used only when it is necessary to partially or completely shut off the flow. When installing taps and valves in the pipeline system, you must look at the arrow - it shows the correct direction of movement. Incorrect installation contributes to the emergence of excess hydraulic resistance, this will affect the service life, can lead to malfunction and malfunctions. The structure of the valve includes ground bushings, which allows it to sit tightly on the seat of the hole.
There are also visual differences. The handles of these locking devices are different - the valve has a "wing", which is necessary for smooth flow control, while the valve has a simple handle that is attached to the stem
The answer to the question "which is better: a tap or a valve?" no. It is impossible to give such an answer, since each type of valves is designed to perform specific tasks. The valve, in contrast to the valve, has design features that facilitate its operation when it is necessary to quickly shut off the flow. This is due to the simpler structure of the handle, since it takes more time to screw in the "wing" of the valve. In terms of service life, the valve is inferior to the valve, its design presupposes sealing elements that periodically break and need to be repaired or replaced. However, in terms of maintainability, the valve has advantages, since in its structure it is possible to replace parts that have failed. If the crane is deformed, a complete replacement is required.
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All pipelines are supplied with appropriate fittings. Its purpose is to open and close the flow of liquid (gas), regulate its temperature, pressure or flow rate, and also protect equipment from off-design modes. In accordance with the purpose, valves can be shut-off, control, safety, power, etc. To what type of valves are taps and valves, and what is their difference?
Definition
Tap- a type of pipeline power fittings in which the valve body rotates around its own axis, located perpendicular to the direction of flow. A typical crane consists of two main elements: a stationary body and a rotating plug.
Ball valve
Valve (stop valve) is a type of actuated valve in which the valve body, moving in the direction of flow, sits on the seat. The valve is designed to open, close and regulate gas or liquid flows.
Valve Comparison
The main difference between a valve and a tap is that a valve can regulate the pressure of a working flow, but a tap cannot (besides, adjustment by a tap is strictly prohibited according to the rules of operation). The valve performs only two functions, having only the position "open" or "closed", and the valve can easily adjust the pressure of the working flow.
It's all about the design differences between the valve and the crane. In valves, the shut-off element sits on the seat, moving in the direction of flow, and in valves it turns around its own axis. In addition, cranes are usually ball-type, that is, when the ball turns, the diameter of the hole changes, and the valves are equipped with a ground axle box (by unscrewing or twisting the stem of the ground axle box, they raise or lower the valve attached to the stem, thereby opening or closing the hole located in saddle).
Conclusions site
- The valve has two positions - this is the "open" position and the "closed" position.
- The design of the valve, in addition to switching on / off, also allows you to regulate the pressure of the working flow.
- Visually, the valve differs from the valve in the following way: if the handle is simple and its end is attached to the stem, it is a valve; if there is a "lamb" on the stem instead of the handle, this is a valve.
Valve and gate valves are the two main elements most commonly used in industrial piping. Without them, it is difficult to imagine any supply system of a more or less large size.
The task of such equipment is simple - to give a person the ability to control the movement and condition of the transported liquid inside the pipes.
Many people unknowingly confuse a valve and a gate valve. 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. Valve and gate valves are really different from each other, but they also have similarities. This article will describe their detailed comparison.
Content of the article
Features and purpose
A valve or gate valve is a shut-off system. According to the standard, they are called shut-off valves.
You have probably already encountered shut-off valves. For example, on any household water supply system, there are probably ones that allow you to restrict the flow of liquid in one direction or another. The complete overlap of the crane 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.
V living conditions valves are most commonly used. Gates and gate valves are also shut-off valves, only of a larger sample.
Placed on pipes up to 100 mm in diameter. The parts described in this article are too large and powerful. It is permissible to mount them on pipes whose diameter only starts from 100 mm (although there are exceptions).
This predominantly means installation on the main branches of water supply systems, heating systems, oil pipelines, oil pipelines, etc.
Interestingly, it is designed so that each element can withstand tremendous 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, as well as to have a complete picture in your head, how the valve differs from the valve, you need to disassemble the principle of operation of each sample. Understand how it works and what it consists of.
But before that, let's pay attention to the ways 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 the valve and the gate valve are made in all variations.
Flanged type of connection implies. A kind of connecting rings welded to the edges of both valves and the pipeline. it a good option when you need reliability combined with practicality.
Flanges are welded to the outlets, then. The connection takes place by tightening the counter flanges on the pipe and valve with bolts. The number of bolts, their size, flange diameter and many other parameters depend on the conditions in each case.
Flanges are most conveniently used in industry, but also in domestic conditions, as well as in civil engineering they are good.
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 that it would be a mistake not to mention it.
They are mounted on pipelines using gas or electric welding. The advantages of such compounds are in their strength. Cons - in the absence of the ability to remove the shut-off valves. And such a need may appear at any moment.
Shut-off valves do not last forever. Dynamic processes are constantly taking place in it. The seals are worn out, the wedge is loosened, the parts are grinded. Sooner or later, the valve will fail. And here's what to do then, the question is open.
They are mainly mounted on threaded connections... This is an intermediate option between welding and flanges. You need to mess around with it more, but you can do without it altogether. welding machine... Are involved in to a greater extent on medium sized civilian systems.
Valve design and principle of operation
Valve - shut-off valves. You should have seen the valves, if not live, then on TV.
This is a large element of the pipeline, slightly thickened 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 fluid inside the pipe.
This is how it differs from the valve. The fact is that the part to be fixed can be in several positions at once.
If you twist it a few turns, then the flow is only partially blocked. The closure will artificially reduce the diameter of the bore inside, which will affect the amount of fluid delivered.
Closing the valve completely blocks 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, it becomes necessary not only to completely shut off the fluid flow, but only to moderate it to certain values. The easiest way to do this is precisely through the installation of valves in a potentially suitable places... More convenient and easy way humanity has not yet come up with.
Parsing the insides
The valve consists of several main parts. The base for all his insides contains 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.
Inside the body there is a hole for the passage of liquid. This hole can be either full-sized or reduced.
The full bore allows full fluid transport and also reduces stress on the inside of the valve. The fluid flows without problems, without encountering resistance.
Miniature valves are another matter. In their basic state, they are not able to pass the 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, and therefore so effective. By rotating the handle, we transfer the force to the screw thread. This affects the position of the valve inside the valve. Twisting the handle lowers the valve, unscrewing it, on the contrary, raises it. Accordingly, you can adjust the movement of the carrier in the tube as you wish.
An important feature is that the liquid flow in the valve is blocked due to the parallel blocking of the flow. This affects the cost of the entire structure, as well as the 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 in several small, but still extremely important design features... Having dealt with them, you will understand exactly what is here and how it works.
The gate valve performs the same tasks as the valve. She is also able to block or open the system at any time.
Only here the valve exists in two positions:
- open;
- closed.
The third option is not given. Its very design simply does not allow for effective partial flow shut-off. The locking element inside is designed according to this scheme for a reason.
B is in a position perpendicular to the carrier. It closes in the same way, moving only a few tens of centimeters down.
This simplifies the design, makes it more unpretentious and cheap. But it also increases the pressure on all the component parts. Especially if it comes 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 die-cast body. It can also be either full bore or standard, with a narrowed diameter.
The main differences relate to the shut-off element itself. V . The closed position of the wedge hides it in the upper saddle section. The wedge does not impede the movement of fluid in the system in any way.
A thread is connected to its guides, and that 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 at one moment. Bottom part the wedge fits into the rubber-sealed inner seats.
The main differences
We 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 regulate the flow in the system, while the valve is in two states: open and closed.
- There is a parallel blocking of the system in the valve, the valve is blocked perpendicular to the flow.
- The valve wears out faster.
- The valve is more expensive, especially its full bore version.
When installing a gas pipeline, water supply and sewerage systems as well as other industrial engineering systems valves and gate valves are indispensable. Many people think that valves are a kind of valves, only of a smaller size, but in fact they are different devices that have significant structural differences that determine the features of their operation. Valves and gate valves have their pros and cons, which determine optimal choice devices for specific conditions of use.
Definition
Valve Is a device that is installed on gas, air, water, steam, oil and other pipelines to open and close openings with a valve. The valve consists of a steel, cast iron or bronze body with a seat for the valve, the valve itself with a threaded spindle and a handle that allows the spindle to rotate. The valves are connected to the pipeline by means of a thread or flanges and are subdivided into coupling and flanged.
Sectional valve
Gate valve Is a device that is installed on pipelines to open and close openings with a valve moving perpendicular to the axis of the flow of the working medium. Depending on the design of the shut-off body, gate valves are divided into hose, slide and parallel. The spindles can be retractable or rotatable.
Sectional valve Comparison
It is due different designs their locking organs. In the valve, the flow of liquid or gas is shut off with the help of a valve pressed against the seat in horizontal planes parallel to the flow, for which a double bend of the flow of liquid or gas at an angle of 90 ° is made, but this increases the resistance to it. In the valve, the flow is blocked by a valve or cone, which is lowered perpendicular to the direction of its movement.
If the valve is correctly designed, then there is no narrowing of the through holes compared to the inlet and outlet, and when using valves, options are possible. In most pipelines, all-wheel drive valves are installed, that is, the diameter of their bore corresponds to the diameter of the pipeline, but sometimes, in order to reduce torques, narrowed valves are also installed, which reduces wear of the sealing surfaces.
At large diameter pipelines (from 300 mm) or high pressure valves work more efficiently in them. The valves have more simple design, which results in their lower cost, they are also easier to rotate at high pressures, but at high pressures, the tendency to squeeze the valve from the seat creates additional stress on the structure. The valve has no resistance at all, since it has no bends. One-way pressure provides a tighter fit between the valve and the seat, making the valve more reliable locking devices.
The blocking elements of the valves can either completely shut off the flow of liquid or gas, or be completely open, while the valves can be used as control elements.
Conclusions site
- The shut-off elements of the valve move parallel to the flow, the valves - perpendicular. This makes the valves more reliable, but allows easier rotation of the valves under heavy loads.
- The valve has a simpler design and, accordingly, a lower cost.
- The valve can only be in two positions (open-closed), and the installation of the valve allows you to adjust the filling level of the pipelines or the volume of consumed gases and liquids.