&

Valves are classified by function and use

ruige — Mon, 23 May 2022 09:01:13 +0000

Cut-off type: such as gate valve, globe valve, plug valve, ball valve, butterfly valve, needle valve, diaphragm valve, etc. The cut-off valve is also called a closed-circuit valve and a globe valve, and its function is to connect or cut off the medium in the pipeline.

Check type: such as check valve, check valve is also known as one-way valve or check valve, check valve belongs to an automatic valve, its function is to prevent the backflow of the medium in the pipeline, prevent the pump and drive motor from reversing, and leakage of container media. The bottom valve of the water pump suction valve also belongs to the check valve category.

Safety category: such as safety valve, explosion-proof valve, accident valve, etc. The function of the safety valve is to prevent the medium pressure in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.

Adjustment type: such as control valve, throttle valve and pressure reducing valve, its function is to adjust the pressure, flow and other parameters of the medium.

Diversion category: such as distribution valve, three-way valve, steam trap. Its function is to distribute, separate or mix the medium in the pipeline.

Special purpose categories: such as pigging valves, venting valves, blowdown valves, exhaust valves, filters, etc. The exhaust valve is an indispensable auxiliary component in the pipeline system, and is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. It is often installed at the commanding heights or elbows, etc., to remove excess gas in the pipeline, improve the efficiency of the pipeline and reduce energy consumption.

Ball valve features

ruige — Mon, 23 May 2022 08:57:33 +0000

Ball valve, the opening and closing member (ball) is driven by the valve stem and rotates around the axis of the ball valve. It can also be used for fluid regulation and control. Among them, the hard-sealed V-shaped ball valve has a strong shear force between the V-shaped ball core and the metal valve seat of hard alloy surfacing, which is especially suitable for fibers and tiny solid particles. etc. medium. The multi-port ball valve on the pipeline can not only flexibly control the confluence, diversion, and switching of the flow direction of the medium, but also can close any channel and connect the other two channels. This type of valve should generally be installed horizontally in the pipeline. The ball valve is divided into: pneumatic ball valve, electric ball valve, manual ball valve according to the driving method.
Ball valve features:
1. Wear-resistant; because the valve core of the hard-sealed ball valve is alloy steel spray welding,
The sealing ring is made of alloy steel surfacing, so the hard-sealed ball valve will not produce too much wear when it is switched on and off. (Its hardness factor is 65-70):
Second, the sealing performance is good; because the sealing of the hard-sealed ball valve is artificially ground, it cannot be used until the valve core and the sealing ring are matched. So his sealing performance is reliable.
Third, the switch is light; because the bottom of the sealing ring of the hard-sealed ball valve adopts a spring to hold the sealing ring and the valve core tightly together, the switch is very light when the external force exceeds the preload of the spring.
4. Long service life: It has been widely used in petroleum, chemical industry, power generation, papermaking, atomic energy, aviation, rocket and other departments, as well as people’s daily life.
The pneumatic ball valve has a simple and compact structure, reliable sealing and convenient maintenance. The sealing surface and the spherical surface are always in a closed state, which is not easily eroded by the medium, and is easy to operate and maintain. It is suitable for general working media such as water, solvent, acid and natural gas. It is mainly used for cutting off Or connect the medium in the pipeline, and can also be used for fluid regulation and control.
Compared with other types of valves, pneumatic ball valves have angular stroke output torque, fast opening, stable and reliable, wide application, and the following advantages:
1. The thrust bearing reduces the friction torque of the valve stem, which can make the valve stem operate smoothly and flexibly.
2. Anti-static function: A spring is set between the ball, the valve stem and the valve body, which can export the static electricity generated during the switching process.
3. Due to the good self-lubricating properties of PTFE and other materials, the friction loss with the ball is small, so the service life of the pneumatic ball valve is long.
4. Small fluid resistance: Pneumatic ball valve is one of the smaller types of fluid resistance among all valve categories. Even the reduced-diameter pneumatic ball valve, its fluid resistance is quite small.
5. Reliable valve stem seal: Since the valve stem only rotates and does not move up and down, the packing seal of the valve stem is not easy to be damaged, and the sealing ability increases with the increase of the medium pressure.
6. The valve seat has good sealing performance: the sealing ring made of elastic materials such as PTFE is easy to seal in structure, and the sealing ability of the pneumatic ball valve increases with the increase of the medium pressure.
7. The fluid resistance is small, and the full-bore ball valve basically has no flow resistance.
8. Simple structure, small size and light weight.
9. Tight and reliable. It has two sealing surfaces, and the sealing surface materials of the ball valve are widely used in various plastics, which have good sealing performance and can achieve sealing. It has also been widely used in vacuum systems.
10. Easy operation, quick opening and closing, the ball valve only needs to rotate 90° from fully open to fully closed, which is convenient for long-distance control.
11. It is easy to maintain, the ball valve has a simple structure, the sealing ring is generally movable, and it is more convenient to disassemble and replace.
12. When fully open or fully closed, the sealing surfaces of the ball and the valve seat are isolated from the medium, and when the medium passes through, it will not cause erosion of the valve sealing surface.
13. Wide range of applications, diameters ranging from small to several millimeters, large to several meters, and can be applied from high vacuum to high pressure.
14. Because the ball valve has wiping property during the opening and closing process, it can be used in the medium with suspended solid particles.
15. High processing precision and high cost. It is not suitable for use in high temperature. If there are impurities in the pipeline, it is easy to be blocked by impurities, resulting in the valve cannot be opened.

Definition of valve

ruige — Mon, 23 May 2022 08:53:52 +0000

By definition, a valve is a specially designed mechanical device to flow, start, stop, mix or regulate the flow, pressure or temperature of a process fluid. Valves can be designed to handle liquid or gas operations. Valves come in many types, sizes and pressure ratings according to their design, function and application characteristics. Small industrial valves can weigh as little as 1 lb (0.45kg) and fit in a human hand. And the big one can weigh more than 10t (9070kg) and the height can reach more than 24ft (601m). Industrial process valves can be used for pipeline sizes from 0.5m [nominal diameter (DN15)] to over 48in (DN1200). However, more than 90% of the valves used in the process system are installed on 4in (DN100) or smaller pipelines. Valve pressure can be used from negative pressure to over 1300 psi (897 bar). An example of how process valve size changes are shown in Figure 1.1. …
Today’s existing valve showers have evolved from simple taps to control valves equipped with a processor that provides single loop control of the process. The types commonly used today are gate, plug, ball, butterfly, check, relief, and globe valves
Valves can be made from many kinds of materials, most valves are made of steel, iron, plastic, brass, bronze or a number of special alloys.