Ball valve or steel gate valve, a matter of choice. Ball valve or gate valve

The flange gate valve is installed on pipelines to provide the possibility of quickly shutting off the liquid supply and subsequent drying of the medium. To increase the level of security, these elements are located in all parts of the network.

Description

The flanged gate valve acts as a shut-off valve and has a simple design, despite its high efficiency. It belongs to the category of shut-off household taps and has a special blocking part in the center of the structure, its execution depends on the type of valve itself. The most widespread are disk locking, wafer wedge and ball rotary elements.

The flange valve got its name due to the special flange rings located at the edges. They are used to provide quick access to the system and the ability to remove a fixture for replacement or repair work. It is worth noting that the dimensions of the mating flange element must correspond to the main plate. Otherwise, the connection will not have the proper quality, or it will become impossible at all.

Advantages and disadvantages

Among the main positive aspects it is worth noting the following:

• enabling quick repair or replacing the device with a new one;
• simple design;
• long term operation;
• low degree;
• reliability.

The main disadvantage is the large mass. This leads to high cost elements, especially large-sized ones, since for their manufacture it is necessary a large number of material. Also worth noting is the rapid wear of the seals.

Varieties

The cast iron flange gate valve is available in various options. Devices are divided into types according to the direction of action - parallel and perpendicular. The latter option is stationary and extends perpendicular to the main flow. Parallel attachments are installed at zero angle and are not obstructive to flow when in standard mode.

There is also a division according to design features - these are gate, ball and wedge-shaped elements. The latter are shut-off valves standard view. They are quite effective, have a perpendicular type of blocking, but are very heavy.

The spherical design is similar to locking household elements of a similar type. The most widely used devices are DU 50 due to their relatively low cost. The flange gate valve DN 100 has a special disc element that closes the pipeline with a powerful spring. As a rule, it is installed on oil pipelines and gas networks.

Classification by control method:

• Handheld devices. This type is controlled manually by turning a special handle or valve. Despite the need for significant physical effort, they do not require maintenance and rarely fail.
• Electric fittings. It has a built-in electric motor for control. Blocking of the system is done autonomously, after pressing the button.

Working conditions

Flanged valve operates in various pressure ranges, maximum level can reach hundreds of units. The operating temperature ranges from +200 to -50 degrees. Cast iron parts are distinguished by extended characteristics, in particular, work with gaseous substances can occur at +400 degrees, and the transported liquid medium can have a temperature of +270 degrees Celsius.

The clinker flanged gate valve is mainly produced from materials such as cast iron and steel. This parameter is located in the label of the device. Any products equipped with flanges must be carefully selected according to the dimensions, which are regulated by special documents. First of all, the diametrical size of the conditional passage is taken into account. If there are any inconsistencies with this criterion, the connection becomes impossible. If a flanged steel product with a size of DN 80 or DN 50 is used for installation, the flange going to the adjacent pipeline must have the same parameters. At the same time, the flanged gate valve, the sliding spindle of which performs rotational-translational movement during opening, can be produced in various sizes. Maximum size can reach up to 1500 mm, the smallest size reinforcement has a diameter of 25 mm.

Scope of application

Elements DN 80 and DN 50 are most widely used in secondary pipelines and side branches of systems. In addition, they are used for large systems for household purposes, taps and in boiler rooms. The flanged gate valve 100 is much larger and is installed on the main heating and water supply pipelines. Products DN 200 are used only in industrial environment on pressure main systems, while large special bolts are used for their installation. The cost of fittings depends on both dimensions and design features. The price of the material used in the manufacture also matters.

Installation

Installation of products is carried out according to standard scheme. At the same time, work is simplified by welding flanges to pipes or shutoff valves. Otherwise, the workers would have to independently connect the valves with additional parts and weld individual elements pipes. This process requires large financial and time costs, and is also characterized by some difficulties, failure to comply with which can lead to problems during operation. This is of particular importance in the industrial sector.

With the help of the element, tightness is increased. It is installed in a channel located on a flange plate. On the front side of the plate there should be no scuffs and any other damage, otherwise there is a possibility of depressurization and a breakthrough of the system. Under the condition of working with pressure head high pressure, this is fraught with serious consequences.

Gate valve or ball valve? These are locking devices used everywhere. They have the same purpose but different design features. Therefore, users are interested in the question, what is the difference between a valve and a faucet. Let's take a look at this issue.

Gate valve: key features

A gate valve is a type of mechanism that has simple design. This is a part consisting of several elements:
frame;
lid;
gate.

The main feature of the valve is that the control mechanism moves at a right angle to the flow of liquid or gas. Manufacturers produce pipe fittings in an extensive range. Therefore, wedge, hose, gate valves are presented in the catalogs of companies. Depending on the location of the running unit, products are developed with a retractable and non-retractable spindle.

Ball valve design: fundamental aspects

To answer the question of how a valve differs from a crane, you need to consider in detail the second option.

A ball valve is a product in which the locking or regulating component is made in the form of a sphere. It consists of a body, a ball, a spindle, a seat and a handle designed for manual operation. The range of stores includes Ball Valves with so-called floating balls and with balls that turn in supports. Depending on the form of connection, parts are flanged, coupling, combined and welded. Therefore, buyers select options based on personal preferences and tasks.

The difference between a gate valve and a ball valve

The difference between the two types pipe fittings essential. Let's consider it in more detail:

1. Construction is a big deal. In the valve, the most important locking element is the wedge. In a ball valve, this function is performed by a shutter in the form of a sphere, inside which there is round hole. Through it in open state running environment.
2. Duration of operation - the service life of the valve is at least 10 years. The average service life is about 2000 cycles. The service life of a ball valve included in the economy segment varies within 15 years. The number of cycles is 4000. The crane, designed for increased loads, has been used for 20 years or more. Its opening/closing life exceeds 10,000 cycles.
3. Practicality - ball valves win. They open with levers, a butterfly handle, a gearbox with a flywheel. It is possible to use an electric drive, a hydraulic drive and a pneumatic drive.

Conditions for the use of locking devices

The gate valve is a hermetic locking element, which is ideal for installation on pipelines. It has been successfully applied in various fields. These are gas and water supply, housing and the oil industry.

Ball valve - modern products, which is widely used in the arrangement of heating systems, water and gas supply of residential buildings, industrial and commercial facilities. Products with a diameter of DN 300 and above are suitable for handling natural gas and oil.

Which is better: gate valve or ball valve

It is difficult to give a definite answer to such a question. Each type of product has certain advantages and disadvantages.

To positive characteristics gate valves include simplicity of design, minimal hydraulic resistance and the ability to use in harsh conditions. There are also disadvantages. This is long time opening / closing mechanism, rapid wear of seals and a sliding spindle in some models.

Ball valve - a product that is characterized by small dimensions, tightness and reliability. Position changes in seconds. The control of the mechanism is simple and convenient. The disadvantage of the product is that free space is needed to accommodate the handle-lever. This must be taken into account when choosing such products.

There is a significant difference between a valve and a faucet. The latch is an outdated option. It is indispensable in the arrangement main pipelines in which the work environment moves rapidly. This is due to the fact that the valve is characterized by low hydraulic resistance. The ball valve has an increased tightness class "A" and practical design. Therefore, it is more often used in various pipeline systems than a wedge device.

The most popular designs today can be considered cranes and valves. Many do not understand the differences between these two types of valves and are guided by the advice of sellers and acquaintances. Sometimes you can even observe the influence of fashion. For example, 10 years ago everyone switched from valves to taps, but now it’s the other way around. However, both of these types of fittings have their own individual characteristics.

gate valve

The operation of the valve is to block the flow of liquid or gas with a locking element. The overlap is made perpendicular to the flow.

The design of the valve is simple, and they themselves are quite unpretentious in operation. Gate valves in open form have little hydraulic resistance. The gate valve works perfectly with a viscous medium, passing it in all directions. One of the most popular brands of gate valves is AVK (avk official website Russia).

Now for the cons. The valve is difficult to regulate the flow. The locking element has only two positions. Either closed or open. For aging high pressure reinforcement must be strong and massive. The locking element wears out over the years, and its repair is very difficult and often requires a complete replacement.

Gate valves are:

• Wedge. It has sealing surfaces at an angle to each other, which ensures good contact regardless of temperature and even corrosion.
• Parallel. Here, respectively, the sealing rings run in parallel. They are used where there is no need for 100% tightness.

Cranes

The locking part of the valve is made in the form of a rotary element with a hole through which the medium is passed. Cranes are conical, ball and cylindrical. Today, the most popular is considered to be a ball valve. Turning the plug can control the flow of the medium from decreasing the flow to full coverage.

Cranes can work both with liquid, and with gas. Unlike valves, they are more compact.

The weak point of any faucet is the seals, which, when worn, violate all tightness. Also, due to non-metallic seals, the faucet cannot withstand various aggressive environments.

In water and gas pipelines, one cannot do without such a device, which is 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 the pipeline, and also be used as safety device and condensate drain.

Device design

The valve device is quite simple, and the product consists of the following main parts:

1. Frame.
2. Locking device.
3. Handwheel or locking handle.

The body of the product is made by casting. A locking device is installed inside the housing, and a flywheel is brought out. The body also has a thread on both sides, through which the valve is connected to a water or gas pipeline. The sectional diagram of the shut-off valve has the following form:

Product classification

The valve for water is classified according to a number of different features, which include:

1. Type and design of the locking device.
2. Manufacturing material.
3. Features of connection with water or gas pipelines.

According to the type and design of the locking device, the valves are divided into the following types:

• Valve.
• Cork or cone.
• Ball.

We will find out the main features of each type of valves, and also determine their purpose.

Valve devices

The valve valve is also called a valve valve, since the body of the product is divided into two parts by a horizontal and inclined partitions. In the design of the product with an inclined partition, there is a hole that has a groove for the valve. Such a hole is called a saddle.

The valve is a part of the stem, 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 such an emphasis on the saddle, the supply of fluid flowing through the device is shut off. At the top, the stem is threaded, which connects to the threaded connection of the seat nut. With this threaded connection the valve is raised and lowered, thereby blocking and regulating the pressure of the supply fluid.

Products of this type have advantages and disadvantages. The pluses include:

1. Withstanding high pressure.
2. Adjustment of volume and pressure of water.
3. Simplicity in management.
4. If the locking device fails, it can be replaced.

The disadvantages of such a device are:

1. The high rate of erasing the gasket, since with the frequent opening and closing of the device, the rubber contacts the metal.
2. Relatively short service life.
3. To completely shut off the fluid 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 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 fluid.

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 principle of operation of this type of valve is completely different from the functioning of the previous options. If previous products provide water shutoff 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 fluid supply is provided by moving the slotted ball to a perpendicular position. Such valves are also called gate valves.

The benefits of these products include:

1. Simplicity of a design that allows to operate the device long time.
2. The tightness of the structure. Only the shut-off ball comes into contact with water, which also affects the long service life of the product.
3. Shutting off and opening the fluid supply is carried out by turning the handle 90 degrees or half a turn. Such devices, due to the rapid shutdown of the fluid supply, are also called semi-circulating.

As practice shows, the quality of valve production has a significant role in the service life. European-made water valves have a service life of up to 10 years, while cheap Chinese counterparts fail after a few years.

The disadvantages of the considered types of valves include:

1. Inability to repair the plumbing ball valve. In Chinese products, the integrity of the connection between the handle and the locking ball is violated. This causes the handle to continue to rotate while the ball stays in place in a wedged position.
2. The inability to control the flow of fluid. It is possible to regulate the flow of liquid using such a product, but manufacturers in this case do not guarantee a long service life of the device.

What is the difference between a valve and a valve

The difference is not in the type of valves, as many people, even plumbers, are used to thinking. Taps and valves are different, although they are often referred to by the same name. This difference lies in the design of the hull. If the valve is intended to be installed at the junction of two pipes, in order to shut off the fluid supply if necessary, then the valve is located at the end of the pipeline. A tap is a kind of limit switch that serves to supply water when such a need arises.

Now you need to find out what is the difference between a valve and a valve. Many people think that there is no difference between a valve and a valve, however, this is not so. What is a valve 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 considered 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 fluid pressure due to its design features. The damper in such a device moves only up and down. What is the difference between a valve and a valve, you can see 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 supply and gas pipelines.

If the product is intended for internal water supply networks, then brass, bronze, stainless steel and plastic devices are used. If the products are used for outdoor work, then the above materials are used for this, as well as additionally steel and cast iron.

1. Plumbing devices made of brass and bronze are expensive options. However, their cost is justified by the quality and durability. Such devices are lightweight, small in size, and can also be installed not only on the water supply for supplying cold water but also hot. Such products are also used in heating systems, since scale does not settle on their surfaces.
2. Stainless steel valves. Another a good option which has a long service life. They are several times cheaper than brass and bronze devices.
3. Plastic products are among the cheapest, but they are in no way inferior in quality to the above models. Their disadvantage is the possibility of installation only in plastic pipelines.

Cast iron and steel valves are popular for outdoor installations. 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 ten times more.

Connecting devices with pipes

Valves according to the method of installation are divided into two types:

1. Coupling and threaded. Main connecting element with this method of connection - this is a thread. It can be internal and external on the valve (popularly called "mom-dad"). Fittings of this type are installed in pipelines with a pressure of not more than 1.6 MPa.
2. Flanged. On the end parts of the nozzles there are flanges, with the help of which the connection of cast iron or steel products is carried out. Installation of such devices is carried out on the main and industrial pipelines where the water pressure exceeds 10 MPa.

Plastic valves are connected to pipelines by special welding. Knowing the features of the devices under consideration, you can choose best option for the appropriate installation. AT recent times ball valves, which have a high service life, despite the lack of the possibility of their repair, are widely popular.

A gate valve is a type of shut-off valve used to block or change the throughput volume of the transported working medium in technological, industrial and sanitary pipelines.

This article presents flanged valves. We will consider wedge, parallel, clink, gate and hose modifications, we will study the design features of the fittings and its performance characteristics.

Article content

Functional purpose and design features

Flanged steel gate valves differ from other types of pipeline fittings in that the locking mechanism in them moves perpendicular to the movement of the working medium. Such designs are produced in diameters of 15-2000 mm, they are designed for installation on pipelines, working temperature in which does not exceed 600 degrees with pressure up to 25 MPa.

Gate valves are widely used in all industries:

• water supply systems and heating communications of housing and communal services;
• oil and gas transport systems;
• main pipelines of the energy industry.

The distribution of this type of pipeline fittings is due to the following operational advantages:

• simplicity and maintainability of the design;
• minimum construction length;
• reliability in difficult conditions operation;
• low level of hydraulic resistance.

Gate valves also have disadvantages, the main of which is the large overall height of the structure, which is especially typical for products with a sliding type spindle, in which the stroke of the stem must be equal to the full diameter of the through hole. Also a disadvantage is the long opening time and the tendency to operational wear of the sealing elements, as a result of which the valves require periodic maintenance and.

Note that the design features of valves do not imply their use as control valves - during operation the locking mechanism must be in the extreme open or closed position, not in the intermediate.

Almost all types of gate valves are manufactured in a full-bore configuration - the cross section of the through hole is identical to the diameter of the pipes on which the product is installed. Reducing gate valves (with a narrowed cross-section of the passage opening) are also produced, but they have a narrow scope of use - they are installed only on pipelines, to control valves on which it is necessary to reduce the torque exerted by the working medium.

The control mechanism in the valves is a manual steering wheel, there are also designs equipped with hydraulic or electric drives, less often with a pneumatic drive. Large gate valves with manual control, for simplification of efforts at opening are completed with a reducer.

Manufacturing technology and materials used

Gate valves, depending on the method of manufacture, are classified into cast and welded. The casting method produces steel, aluminum and, with the help of a welding joint, titanium and some varieties of steel products. In terms of strength and reliability, welded structures are practically not inferior to cast counterparts.

The sealing elements of the fittings can be made of PTFE, brass or rubber. Elastic materials (rubber and synthetic rubber - EPDM) are most often used in production (where the walls of the locking mechanism are covered with rubber) and hose structures (a pinch hose is made of rubber).

Gate valves have a type marking unified according to GOST No. 9698 30nzh42p du50, wherein:

• 30 - nomenclature of reinforcement (the number 31 can also be used);
• nzh - designation of the material from which the structure is made, in this case, nzh - stainless steel(s - carbon steel, ls - alloyed steel, h - cast iron, tn - titanium);
• 42 - model number;
• p - material for the manufacture of sealing elements (p - plastic, br - bronze or brass, p - rubber, p - plastic);
• DN50 - diameter 50 mm (varies within 15-2000 mm).

Mounting flange gate valve Du219 (video)

Principle of operation and varieties

The principle of operation of all types of valves is similar to each other. The valve body and cover form a cavity in which the locking unit is placed. Flanges are placed on the body, through which the valve is connected to the pipeline. Depending on the type of connection, the design can be flanged and wafer, which is clamped between the flanges of adjacent sections of the pipeline (wafer gate valve has much smaller dimensions.

Inside the body, next to the locking element, there are two seats (parallel or at a certain angle to each other). The adjustment of the shutter is carried out by rotating the actuator, to which the locking mechanism is connected by means of a stem. Depending on the principle of movement of the stem, the valve can be retractable (the stem performs rotational translational movement when closing) or rotary (exclusively rotational movement).

The stem is installed inside the running nut, this assembly is called a threaded pair. The nut, when the drive rotates, ensures the movement of the locking element in a given direction. When the valve is moved to the closed position, its walls are pressed against the sealing surfaces of the seat, while in the open position the valve completely exits the body bore.

The main classification of valves is carried out depending on the type of locking mechanism, according to which valves are divided into:

• wedge;
• parallel;
• gate;
• hose.

The shutter has a conical shape; when closing, it enters the saddles located at a given angle to each other and closes the through hole. wedge, depending on design, can be rigid or clinket.

The wedge of the rigid type (steel) provides maximum tightness in the closed position, however, the operation of this design may be accompanied by a number of problems associated with the valve jamming due to temperature fluctuations or damage to the sealing surfaces due to corrosion.

The gate valve flanged has a gate, consisting of two located at an angle to each other, which are rigidly connected to each other. This design is highly reliable - it does not jam, the seals are subject to minimal wear and much less effort is required to change the position of the valve. Flanged gate valve is the most common type of ship fittings.

The valve consists of two discs that move between parallel sealing seats. A variation of the parallel design is, in it the locking unit has a similar design, however, the shutter consists of 1 disk.

Slide valves are installed on pipelines with one-way movement of the working medium. Due to the simplicity of the design, it is not able to provide maximum tightness of the ceiling, however, the slide gate is maintainable, which allows the use of such designs in sewage and sewer systems that transport liquids with a high content of mechanical particles.

Hose-type valves are fundamentally different from the previously considered counterparts. There are no sealing seats in their design - the working flow circulates inside the elastic rubber hose which completely isolates internal surfaces body from the transported liquid. The blocking of the flow is carried out by pinching the hose with a rod.

Such designs are intended for installation on pipelines transporting viscous substances and chemically aggressive liquids, under the influence of which accelerated corrosion of steel occurs - rubber is a material that is resistant to most chemical compounds. Operation of these valves is possible at temperatures up to 110 degrees and working medium pressure up to 1.6 MPa.