Comparison of ball valve and shutoff valve. The difference between a valve and a valve

All pipelines are equipped with the necessary fittings. The purpose of which is to open and shut off the flow of water or gas, regulate their pressure, temperature or flow, and also protect the product from off-design regimes. According to the purpose, valves can be shut-off, safety, drive, control, etc.

What kind of faucet and valve belong to, what is their difference and what is better - you will learn from our article.

The valve refers to pipeline actuator fittings in which the gate mechanism rotates around its axis located transverse to the direction of flow. A conventional faucet consists of two main elements - a fixed body and a rotating plug.

ball valve

A valve (or in other words a shut-off valve) is a type of actuator valve in which the valve mechanism moves in the direction of flow, sitting on the seat. The purpose of the valve is to open, close and regulate the flow of liquid or gas. Next, let's take a closer look at the difference between a valve and a faucet.

The difference between a faucet and a valve: a comparative characteristic

The main difference between a ball valve and a valve is the adjustment of the pressure of the working medium. A crane cannot make such an adjustment, but a valve can. Moreover, taking into account the requirements for the operation of cranes, it is strictly forbidden to regulate the pressure with their help.

The crane performs only two functions: to open and close the flow of the working medium. A valve, on the contrary, can easily adjust the pressure of water or gas.

Such a difference is determined by design. The locking mechanism in this product moves in the direction of flow and as a result sits on the seat. And in cranes, this mechanism rotates around its own axis.

In addition, there is Ball Valves. In the device of such cranes as locking mechanism a ball turning transversely to the flow protrudes, which ultimately changes the diameter of the pipe. In the design of the valves - grundboxes. Such design implies that, by moving the stem, the bottom boxes raise or lower the shut-off valve. This valve is connected to the stem. So, the opening or closing of the hole located in the saddle is carried out.

Visually, what is the difference between a faucet and a valve is easy to determine. If the shut-off valve has a simple handle, and its end is attached to the stem, this is a tap. If instead of a handle on the stem there is a “lamb” - this is a valve.

What is better faucet or valve?

Here it is impossible to say unequivocally that a valve or a ball valve is better. We only note that the faucet is easy to use: by turning the handle 90◦, it blocks the flow of water. While the shut-off valve (valve) must be wrapped in order to open or close the water supply.

The valve has valves with gaskets, which, when worn, can be easily replaced with new ones. At the same time, it will still be necessary to change the seal over time. Ball valves do not have this problem. Here it is only necessary to constantly care for the surface of the ball so that it is in perfect condition.

In general, if you have hard water, it is better to install a valve, because it is subject to partial repair. And if the valve is damaged, then it will need to be completely replaced.

And also a valve for a crane can be bought much cheaper than a ball product - from only 20 rubles. all diameters. Such a low cost is due to the simpler design of the shut-off valve (valve).

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Comparative characteristics of valves

General characteristics of different types of valves

Shut-off valves are used in the construction of gas and sewer systems. It can be seen on pipelines general purpose, industrial type, industrial pipelines with special working conditions, plumbing pipelines and many others. They are designed to block any water or gas flows.

For these purposes, a gate valve, tap, valve, valve, as well as other locking mechanisms are used. Household plumbing is not complete without such mechanisms, but few people understand how a faucet differs from a valve. Without this, it is simply impossible to connect household appliances, fix the leak, turn off the gas or change the mixer. Plumbing surrounds us all the time, and valves are an integral part of it.

In fact, it has significant differences, both constructive and operational, although any constructive solution This type of fitting always works in two positions: closed and open.

But based on their functional characteristics and scope, one or another type of device is selected. For right choice you should know how the principle of their work may differ, and what function each of them performs.

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Principles of operation of a faucet, valve and gate valve

Structural solutions for shut-off valves are taps, valves and gate valves. How do they differ from each other?

Latches are the most widespread and most demanded locking devices. Their design implies that the locking element is in the closed and open position. The flow of the working medium is blocked due to the fact that the locking element moves perpendicular to its axis. Gate valves can only be used as shut-off valves. They are parallel, wedge and gate.

The valve or valve is able to block the flow of the working medium due to the fact that the device moves parallel to the axis of its movement. It, unlike gate valves, can be used not only as a blocking device, but also as a regulating device, due to the fact that its design will allow you not to completely block the flow of the medium, but partially.

To significant shortcoming can be attributed to the inability of the valve to respond to changing speed and pressure in the system. Therefore, its scope is pipelines with a relatively constant flow and pressure of the working medium. In addition to regulatory and locking devices, distinguish bypass, mixing, as well as distribution structures these mechanisms.

A faucet is another type of shutoff valve. It can be used as a blocking or regulating device. It functions as follows: the locking element, rotating around its axis, moves in the direction perpendicular to the movement of the medium flow. The locking element is disc-shaped. Due to its rotation around its own axis, the liquid overlaps in a perpendicular direction.

Modern plumbing offers various design solutions for valves, which have their own characteristics. Of course, this entails the presence of distinctive advantages and disadvantages, which appear in different conditions. Therefore, in order to choose the right valves, it is necessary to take into account the design features of the pipeline, as well as the conditions of use and requirements for a particular device. To do this, you need to understand how, for example, a tap differs from a valve, because the difference between them is not so obvious.

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Comparative characteristics of a faucet and a valve

The main difference between a faucet and a valve is the adjustment of the pressure of the working medium. A valve can make this adjustment, but a tap cannot. Moreover, given the rules for operating cranes, it is strictly forbidden to regulate the pressure with their help. The crane has only two functions: to open and close the flow of the medium. But the valve can easily regulate the pressure of a liquid or gas.

This difference is due to the design. The locking element in this device moves in the direction of flow and eventually sits on the saddle. In cranes, it rotates around its axis. In addition, there are ball valves. In their design, the locking element is a ball that rotates perpendicular to the flow, as a result of which the diameter of the pipe changes. But the valves are equipped with a grun-box. This constructive solution implies that, by moving the stem of the bushing, the valve, which is attached to the stem, is raised or lowered. Thus, the opening or closing of the hole, which is located in the saddle, occurs.

Visually, it is easy to distinguish a valve from a faucet. If the shutoff valve has a simple handle, and the end of this handle is attached to the stem, then this is a tap. If there is a lamb in place of the handle on the stem, this is a valve.

When constructing a gas pipeline, water supply and sewer systems, as well as other industrial engineering systems do not do without valves and valves. Many people think that valves are a kind of valves, only smaller, but in fact they are different devices, which have significant structural differences that determine the features of their operation. Valves and valves have their pros and cons, which determine optimal choice devices for specific application conditions.

Definition

Valve- this is a device that is installed on gas, air, water, steam, oil and other pipelines for opening and closing through holes using a valve. The valve consists of a steel, cast iron or bronze body with a seat for the valve, the valve itself with a spindle with a screw thread and a handle that allows the spindle to rotate. Valves are connected to the pipeline using threads or flanges and are divided into coupling and flanged ones.

Sectional valve

gate valve- this is a device that is installed on pipelines for opening and closing through holes using a valve that moves perpendicular to the axis of the flow of the working medium. Depending on the design of the shutoff valve, valves are divided into hose, gate and parallel. Spindles can be retractable or rotatable.

Comparison

It is conditioned different design their locking organs. In the valve, the flow of liquid or gas is blocked by means of a valve pressed against the seat in horizontal planes parallel to the flow, for which a double bend of the liquid or gas flow is made at an angle of 90 °, but this increases its resistance. In the valve, the flow is blocked by a damper or a cone lowered perpendicular to the direction of its movement.

If the valve is properly designed, then there is no narrowing of the through holes compared to the inlet and outlet, and when using gate valves, options are possible. In most pipelines, all-wheel drive gate valves are installed, that is, the diameter of their through hole corresponds to the diameter of the pipeline, but sometimes, in order to reduce torques, narrowed gate valves are also installed, which reduces wear on sealing surfaces.

With a large diameter of pipelines (from 300 mm) or high pressure valves work more efficiently in them. Valves have more simple design, resulting in lower cost, they are also easier to rotate at high pressures, but at high pressures, the tendency to push the valve away from the seat places additional stress on the structure. There is absolutely no resistance in the valve, since it has no bends. One-sided pressure ensures a tighter fit of the valve to the seat, which makes the valves more reliable shut-off devices.

The blocking elements of gate valves can either completely shut off the flow of liquid or gas, or be completely open, while valves can be used as control elements.

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1. The shut-off elements of the valve move parallel to the flow, the gate valves move perpendicularly. This makes the valves more reliable, but allows the valves to turn more easily under heavy loads.
2. The valve has a simpler design and, accordingly, more low cost.
3. The valve can only be in two positions (open-closed), and the installation of the valve allows you to adjust the filling level of pipelines or the volume of gases and liquids consumed.

Comparison of valve and gate valve

What is the difference between a valve and a gate valve? It is due to the different design of their locking organs. In the valve, the flow of liquid or gas is blocked by means of a valve pressed against the seat in horizontal planes parallel to the flow, for which a double bend of the liquid or gas flow is made at an angle of 90 °, but this increases its resistance. In the valve, the flow is blocked by a damper or a cone lowered perpendicular to the direction of its movement.

If the valve is properly designed, then there is no narrowing of the through holes compared to the inlet and outlet, and when using gate valves, options are possible. In most pipelines, all-wheel drive gate valves are installed, that is, the diameter of their through hole corresponds to the diameter of the pipeline, but sometimes, in order to reduce torques, narrowed gate valves are also installed, which reduces wear on sealing surfaces.

With a large diameter of pipelines (from 300 mm) or high pressure, gate valves work more efficiently in them. Valves, on the other hand, have a simpler design, resulting in their lower cost, they are also easier to rotate at high pressures, but at high pressure, the desire to press the valve from the seat places an additional load on the structure. There is absolutely no resistance in the valve, since it has no bends. One-sided pressure ensures a tighter fit of the valve to the seat, which makes the valves more reliable shut-off devices.

The blocking elements of gate valves can either completely shut off the flow of liquid or gas, or be completely open, while valves can be used as control elements.

TheDifference.ru determined that the difference between a valve and a gate valve is as follows:

1. The shut-off elements of the valve move parallel to the flow, the gate valves move perpendicularly. This makes the valves more reliable, but allows the valves to turn more easily under heavy loads.
2. The valve has a simpler design and, accordingly, lower cost.
3. The valve can only be in two positions (open-closed), and the installation of the valve allows you to adjust the filling level of pipelines or the volume of gases and liquids consumed.

Control valves and gates Many technological processes in engineering, proceeding with the participation of liquids and gases, require the provision of a predetermined regime determined by temperature, pressure, and concentration of components. Regulation of the operating mode of the installation, unit, system is carried out by changing the flow rate of the corresponding medium. So, the temperature in the furnace is controlled by the amount of fuel oil supplied to the furnace, the pressure in the power plant - by the amount of steam, the concentration - by the mass content of the corresponding component. The change in the amount of the working medium flowing through the pipeline is carried out by control valves, which include control valves, control valves and pressure regulators. With the help of the valve, only periodic stepwise regulation is carried out. Continuous and stepless regulation is carried out by means of control valves equipped with a drive. They are the executive device in the system automatic regulation technological processes. The pressure regulator is an automatically operating standalone device, consisting of a control valve equipped with a drive controlled by a sensitive element that reacts to the pressure of the working medium, without the use of an external energy source. The classification of control valves and valves is shown in diagrams 2.5 and 2.6, and their standard designs- in fig. 2.85-2.97. The simplest control device is a control valve, which differs from a shut-off valve in the shape of the shutter, and sometimes in the design of the entire working body. Control valve designed and used for high pressure drops (p< 0,5), называется дроссельным. Для изменения расхода через вентиль затвор перемещается относительно седла, перекрывая его отверстие в большей или меньшей степени. Для этой цели в вентиле используется ходовой узел, состоящий из шпинделя и ходовой гайки, снабженных трапецеидальной резьбой. Затвор, предназначенный для регулирования, называется п л у н ж ер о м. Плунжеры бывают пяти основных типов: стержневые, полые (юбочные), сегментные, тарельчатые и перфорированные (клеточные). Наиболее часто в вентилях применяются стержневые (игольчатые) плунжеры, в клапанах - стержневые и полые. В регулирующем органе арматуры со стержневым плунжером регулирование расхода среды осуществляется изменением площади кольцевой щели между седлом и плунжером, в полых изменяется открытая площадь окон плунжеров для прохода среды,в сегментных изменяется площадь щели, имеющей форму сегмента. Тарельчатые плунжеры обычно применяются в регуляторах давления (двух-седельных). Перфорированный плунжер представляет собой полый цилиндр с a large number through holes on the side surface. It is used for clean media with large pressure drops across the shut-off valve. Control valves can be single seated or double seated. The most commonly used two-seated control valves. Single seat valves are used only when the plunger area is small or a reliable tightness of the valve in the closed position is required. The disadvantage of single-seated valves is the imbalance of the plunger, which, with large seat diameters, creates large longitudinal (adjustable) forces on the plunger. In the power industry, single-seated control valves with cable control are used. The cable is attached to the end of the lever that controls the plunger. The cable can create only one-sided (pulling) force, the load acts in the opposite direction, which creates a force closure of the system. The load on the lever must create a force along the spindle that exceeds the force from the pressure of the working medium on the plunger and the friction force. These valves are installed in such a way that the rotation of the lever occurs in a vertical plane. Control is carried out using a remote control column, or an automatic control system drive. Can also be used manually and mechanically remote control. Cable control is simple and reliable, but is suitable only in conditions where control is carried out with relatively little long distances within the same building. If it is necessary to control from large distances, not mechanical, but electrical or pneumatic methods are usually used. Scheme 2.6 Classification of control valves The most widely used double-seated control valves with diaphragm pneumatic actuator and spring load. They are managed compressed air supplied from an external source, and can be used for automatic continuous stepless control when operating on various parameters and properties of the medium and for various conditions operation. The power spring of the actuator creates a proportional relationship between force and stroke, due to which a proportional dependence between command pressure and plunger stroke. Control valves can be either NO (normally open) or NC (normally closed) action, depending on whether the valve is open or closed when the actuator diaphragm is not pressurized. Rice. 2.85. Steel single-seat control valves: a - with a rod plunger, lever type with nozzles for welding for water (py = 1 MPa, ^p<250°С); б -с поршневым плунжером рычажный фланцевый для пара (Ру= 1,6 МПа, <р<500°С) Рис, 2.86. Клапаны регулирующие стальные двухседельные рычажные с патрубками под приварку для воды и пара (Ру = 2,5 МПа, < 400 °С): а - со стержневым плунжером; б - с полым плунжером В; некоторых, случаях может быть использован беспру-жинный регулирующий клапан, привод которого имеет две мембраны и две герметично изолированные полости. В одну из полостей подается сжатый воздух или газ, упругость которого используется взамен пружины. Во вторую полость подается командное давление воздуха. Упругость сжатого воздуха в полости нагружения определяет собой силовую характеристику регулирующего клапана: ход - давление командного воздуха. Рис. 2.92. Клапаны регулирующие стальные двухседельные флан-цевые с мембранным исполнительным механизмом (МИМ) для жидких и газообразных сред {ру ~ 4 МПа, /р < 300 °С): а - со стержневым плунжером; б - с полым плунжером Такие регулирующие клапаны не получили широкого применения. На их работу могут оказывать влияние колебания температуры окружающего воздуха и возможные утечки воздуха или газа из полости нагружения. Основные параметры и конструктивные разновидности регулирующих клапанов (с поступательным перемещением плунжера по направлению потока среды в клапане) для условных диаметров прохода Dy = 6-400 мм и /^у < 32 МПа регламентированы ГОСТ 9701-79. Рис. 2.97. Вентили регулирующие стальные угловые со стержневым плунжером: а - фланцевый для жидких и газообразных нефтепродуктов (уОу = 32 МПа, ^ 200 °С); 6 - цапковый для жидких и газообразных сред (р - 200 МПа, tp < 200 °С) Регулирующие клапаны изготовляют из чугуна, стали, коррозионно-стойкой стали. Для коррозионных сред применяют мембранные клапаны с внутренним коррозионно-стойким покрытием и шланговые регулирующие клапаны. Применяются также мембранные и шланговые регулирующие вентили. Мембранные и шланговые клапаны и вентили не имеют плунжера, которому можно было бы придать форму, необходимую для обеспечения требуемой пропускной характеристики. В мембранном клапане пропускная способность изменяется путем перемещения мембраны относительно седла корпуса, а в шланговом-путем пережима шланга. Мембранные и шланговые вентили и клапаны обладают высокой коррозионной стойкостью, но срок их службы и энергетические параметры рабочей среды ограничены. В энергетике в качестве регулирующей арматуры применяются также однодисковые (шиберные) задвижки и краны с цилиндрическим полым затвором, снабженным круглым или профилированным проходным отверстием. Опыт показал, что в условиях высоких давлений и температур такие регулирующие устройства в виде шиберных задвижек по своим эксплуатационным качествам превосходят обычные регулирующие клапаны. Задвижка имеет плоский диск (шибер), который под действием давления рабочей среды (вода, пар) плотно прижимается к уплотнительному кольцу корпуса. Они выпускаются с бесфланцевым присоединением крышки к корпусу; управление производится с помощью электропривода. Регулирующие клапаны с мембранным пружиннььм исполнительным механизмом (МИМ) могут быть снабжены дополнительными устройствами (блоками), расширяющими области применения регулирующих клапанов и способствующими повышению точности работы клапана. К таким блокам относятся: верхний и боковой ручные дублеры, позиционные реле (позиционеры), датчики положения, фиксаторы и др. Основные параметры регулирующих клапанов регламентированы ГОСТ 25866-83, © Geyz. ru

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 sizes.

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 unconsciously 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, lies in the middle. Valves and valves are indeed different from each other, but they also have similarities. This article will describe their detailed comparison.

Article content

Features and purpose

A valve or gate valve is a shut-off system. According to the standard, they are called stop valves.

You have probably already encountered shutoff valves. For example, on any household water supply system, they probably stand, allowing you to limit the flow of liquid in one direction or another. Complete shutdown 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.

In domestic conditions, valves are most often used. Valves and gate valves are also shutoff valves, only of a larger sample.

Placed on pipes with a diameter of up to 100 mm. 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).

It mainly implies 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 enormous pressure in the 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 the valve, like the gate valve, has a similar structure and is used for similar tasks. In order to compare them with each other, and also to have a complete picture in your head, how the valve differs from the valve, you need to analyze the principle of operation of each sample. Understand how it works and what it consists of.

But before that, let's pay attention to how they are connected 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. What a valve, what a valve 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 is a good option when you need reliability combined with practicality.

Flanges are welded onto the outlets, then. The connection is made by tightening the mating 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 they are also useful in domestic conditions, as well as in civil engineering.

About welded joints, I think you already know enough. Welded valves are not as popular as flanged or socket valves, but they are also quite widely represented on the market, which means that it would be a mistake not to mention them.

They are mounted on pipelines by gas or electric welding. The advantages of such compounds are their strength. Cons - in the inability to remove the shut-off valves. And such a need may arise at any time.

Shutoff valves are not eternal. Dynamic processes are constantly taking place in it. The seals wear out, the wedge loosens, the parts are ground off. Sooner or later the valve will fail. And what to do then, the question is open.

Mounted mainly on threaded connections. This is an intermediate option between welding and flanges. You need to mess with it more, but you can do without a welding machine at all. They are used to a greater extent on medium-sized civilian systems.

The design and principle of operation of the valve

Valve - shutoff valves. You should have seen the valves, if not live, then on TV.

This is a large pipeline element, slightly thickened and with a large control ring, which is actually called a valve. The task 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 fixed part can be in several positions at once.

If you twist it a few turns, then the flow is only partially blocked. The locking element will artificially reduce the diameter of the through hole inside, which will affect the amount of liquid delivered.

Completely closing the valve blocks the entire system, just like it does. This ability to choose the position for the locking element inside the valve is its main advantage.

Very often in industrial pipelines there is a need not only to completely block the flow of liquid, but only to moderate it to certain values. The easiest way to do this is through the installation of valves in potentially suitable places. Humanity has not yet come up with a more convenient and simple way.

Parsing the insides

The valve consists of several main parts. The base for all its innards contains a powerful body.

The body is predominantly cast, not collapsible. But there are different models, each specific scheme undergoes some changes, in accordance with the expectations and desires of the manufacturer.

Inside the case there is a hole for the passage of fluid. This hole can be either full-sized or reduced.

The full-length passage makes it possible to transport the liquid to the full extent, and also reduces the load on the inside of the valve. The fluid flows without problems, without encountering resistance.

Another thing is miniature valves. In their basic state, they are not capable of passing the nominal amount of the carrier in the same period of time.

In the central part of the body there is a valve lock or just 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 turning the handle, we transfer force to the screw thread. It 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 pipe as you wish.

An important feature is that the flow of liquid in the valve is blocked due to the 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.

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.

There is no third option. Its very design simply does not allow to effectively block the flow in a partial way. The locking element inside is designed according to such a scheme 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 when it comes to mounted on high pressure pipelines.

Installation of a huge industrial valve (video)

Assembly diagram

In many ways, the 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. AT . The closed position of the wedge hides it in the upper saddle. The wedge does not interfere with the movement of fluid in the system.

A thread is connected to its guides, and that is controlled by turning 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, at one moment blocking the entire pipe. The lower part of the wedge goes into the inner saddles sealed with rubber.

Main differences

Let's 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:

1. The valve can regulate the flow in the system, while the valve is in two states: open and closed.
2. In the valve there is a parallel blocking of the system, the valve is blocked perpendicular to the flow.
3. The latch wears out faster.
4. The valve is more expensive, especially its full bore version.