Difference and type selection between the hottest

Difference and type selection between stop valve and gate valve

the opening and closing part of gate valve is the ram, and the movement direction of the ram is perpendicular to the fluid direction. The gate valve can only be fully opened and fully closed, which is not suitable for regulation and throttling. The ram has two sealing surfaces. The two sealing surfaces of the most commonly used wedge gate valve form a wedge, and the wedge angle varies with the valve parameters, usually 5O. The gate of wedge gate valve can be made into a whole, which is called rigid gate valve; It can also be made into a ram that can produce slight deformation to improve its processability and make up for the deviation of the angle of the sealing surface in the processing process. This kind of ram is called an elastic ram

when the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the ram can be pressed against the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface, which is self sealing. Most gate valves are sealed by force, that is, when the valve is closed, the gate must be pressed against the valve seat by external force to ensure the tightness of the sealing surface

gate valve has the following advantages:

1 The fluid resistance is small, and the sealing surface is scoured by the medium. The aviation industry is the dominant market and the erosion is small

2. Opening and closing is labor-saving

3. The flow direction of the medium is unrestricted, without disturbing the flow and reducing the pressure

4. The utility model has the advantages of simple shape, short structural length, good manufacturability and wide application range

nominal pressure or pressure class: pn1 0mpa, ANSI class lb, jisk

nominal diameter or caliber: dn10~1000 NPs 1/2~36 "

connection mode: flange, butt welding, thread, etc.

applicable temperature: -196 ℃ ~700 ℃

driving mode: manual, bevel gear transmission, pneumatic, electric, hydraulic, pneumatic hydraulic linkage, electro-hydraulic linkage

valve body material: WCB, zg1cr18ni9ti, zg1cr18ni12mo2ti, CF8 (304), CF3 (304L), CF8M (316), cf3m (316L) 、Ti。 Different materials can be used for water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media. Stop valve refers to the valve whose closing part (disc) moves along the center line of the valve seat. According to this moving form of the disc, the change of the valve seat opening is in direct proportion to the disc stroke. Because the valve stem opening or closing stroke of this kind of valve is relatively short, and has a very reliable cut-off function, and because the change of the valve seat opening is in direct proportion to the stroke of the valve disc, it is very suitable for the regulation of flow. Therefore, this type of valve is very suitable for cutting off or regulating and throttling

the selection principle is:

1. Stop valves should be selected on pipelines or devices with high temperature and high pressure media. Such as thermal power plants, nuclear power plants, high-temperature and high-pressure pipelines of petrochemical systems

2. On the pipeline with lax requirements for convection resistance. That is, where the pressure loss is not considered much

3. Small valves can be needle valve, instrument valve, sampling valve, pressure gauge valve, etc

4. There is flow regulation or pressure regulation, but the requirement for regulation accuracy is not high, and the pipeline diameter is relatively small. For example, on the pipeline with nominal diameter ≤ 50mm, it should be selected

5. High pressure angle stop valve or high pressure angle throttle valve with nominal pressure P 6n160, nominal pressure 16MPa or pn320, nominal pressure 32Mpa should be selected for small and large chemical fertilizers in the production of synthetic industry

6. In the desilication workshop in the production of alumina Bayer process, it is easy to choose the valve body separation type, valve seat testable machine. It is a common DC stop valve or DC throttle valve with cemented carbide sealing pair that is removed by the laboratory machine

7. In water supply and heat supply projects in urban construction, for pipelines with smaller nominal diameter, stop, balance valve or plunger high-purity rare earth compound valve can be selected, such as pipelines with nominal diameter less than 150mm

the most obvious advantage is:

in the process of opening and closing, the friction between the valve disc and the sealing surface of the valve body is smaller than that of the gate valve, so it is wear-resistant. The opening height is generally only 1/4 of the valve seat channel diameter, so it is much smaller than the gate valve. Generally, there is only one sealing surface on the valve body and disc, so the manufacturing process is relatively good and convenient for maintenance

nominal pressure or pressure class: pn1 0mpa, ANSI class, jisk

nominal diameter or caliber: dn10~500 NPs 1/2~36 "

connection mode: flange, butt welding, thread and other applicable temperatures: -196 ℃ ~700 ℃

driving mode: manual, bevel gear transmission, pneumatic, electric, hydraulic, pneumatic hydraulic, electro-hydraulic linkage

valve body materials: WCB, zg1cr18ni9ti, zg1cr18ni12mo2ti, CF8 (304), CF3 (304L), CF8M (316), cf3m (316L) 、Ti。 Different materials can be used for water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media