News information

Valve Science Popularization

2019/9/19 15:26:02

(1) Shut-off valves

This kind of valve is open and close. Permanent in cold and heat sources, equipment, branch lines (including risers), can also be used as drain valves and vent valves. Common shutoff valves are gate valves, globe valves, ball valves and butterfly valves.

Gate valves can be divided into open bar and hidden bar, single gate and double gate, wedge gate and parallel gate, etc. Gate valve closing tightness is not good, the opening of large diameter gate valve is difficult; along the direction of water flow, the size of valve body is small, flow resistance is small, and the nominal diameter span of gate valve is large.

Globe valves can be divided into three types according to the flow direction of medium: straight-through type, right-angle type and direct-current type, which can be divided into open rod and dark rod. The closing tightness of globe valve is better than that of gate valve. The valve body is long and the flow resistance is large. The maximum nominal diameter is DN200.

The valve core of the ball valve is a round ball with an opening. The plate-operated valve stem makes the sphere opening fully open to the pipeline axis and turn 90 degrees to fully closed. Ball valves have a certain regulation performance and close tightly.

The valve core of the butterfly valve is a circular valve plate, which can rotate along the vertical axis of the vertical pipeline. When the valve plate plane is consistent with the axis of the sub-valve, it is fully open; when the gate plane is perpendicular to the axis of the sub-valve, it is fully closed. Butterfly valve body length is small, flow resistance is small, higher than gate valve and globe valve price.

(2) Check valves

This kind of valve is used to prevent medium backflow. It opens by itself using the kinetic energy of the fluid and closes automatically when it flows backwards. Permanent at pump outlet, trap outlet and other places where reverse flow of fluid is not allowed. Check valves are divided into three types: swing-open, lifting and clamping. For swing check valves, fluids can only flow from left to right, and automatically close when flowing backwards. For lift check valves, when the fluid flows from left to right, the spool rises to form a path, and when the reverse flow occurs, the spool is pressed to the seat and closed. For the clamp check valve, when the fluid flows from left to right, the valve core is opened to form a path, and when the reverse flow, the valve core is pressed to the seat and closed. For the clamp check valve, it can be installed in many places, with small volume, light weight and compact structure.

(3) Regulating valves

When the pressure difference between front and back of the valve is constant, the flow rate of the ordinary valve changes little when the opening of the valve varies in a large range, but when a certain opening, the flow rate changes sharply, that is, the regulating performance is not good. The regulating valve can change the resistance number of the valve by changing the core stroke according to the direction and size of the signal, so as to achieve the purpose of regulating the flow rate of the valve. Regulating valves are divided into manual control valves and automatic control valves, while manual or automatic control valves are divided into many types, and their regulating performance is also different. Automatic control valves include self-operated flow control valves and self-operated differential pressure control valves.

(4) Vacuum

Vacuum categories include vacuum ball valves, vacuum baffle valves, vacuum inflation valves, pneumatic vacuum valves, etc. Its function is to change the direction of air flow, adjust the size of air flow, cut off or put through the pipeline of the vacuum system components called vacuum valves.

(5) Special-purpose categories

Special uses include pigging valves, vent valves, sewage valves, exhaust valves, filters, etc.

Exhaust valve is an essential auxiliary component in pipeline system, which is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. Often installed at the elevation point or elbow, to eliminate excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption. Cixi Kaidi Electronics is a professional manufacturer of valves!