Switching valves is something we encounter every day in our daily life. However, it is such small stainless steel valves that people who do not know knowledge will operate dangerously, so we must pay attention to many details in our daily life.
First, for the types of valves, Needle valve supplier will introduce you
"The gate valve is used as a cut-off medium, and the entire circulation is straight through when it is fully opened. At this time, the pressure loss of the medium operation is minimal. Ball valve wholesale is generally suitable for not requiring frequent opening and closing, and keeping the gate fully open or fully closed. The working condition is not suitable for regulation or throttling. For high-speed flowing media, the gate can cause vibration of the gate under local opening conditions, and the vibration may damage the sealing surface of the gate and the seat, and throttle The gate will be subject to medium erosion. From the structural form, the main difference is the form of the sealing element used. According to the form of the sealing element, the gate valve is often divided into several different types, such as: wedge gate valve, parallel Gate valves, parallel double gate gate valves, wedge double gate gates, etc. The most commonly used forms are wedge gate valves and parallel gate valves. "
The valve stem axis of the globe valve is perpendicular to the sealing surface of the valve seat. The opening or closing stroke of the valve stem is relatively short, and it has a very reliable cut-off action, making this valve very suitable as a medium for cut-off or adjustment and throttling. Once the valve flap of the globe valve is in the open state, there is no longer contact between its valve seat and the sealing surface of the valve flap, and it has a very reliable cut-off action. This kind of valve is very suitable as a medium for cutting or adjusting Stream usage.
Once the shut-off valve is in the open state, there is no contact between its seat and disc sealing surface, so its sealing surface wears less mechanically, because most seats and flaps of globe valves are easier to repair or replace It is not necessary to remove the entire valve from the pipeline when sealing the component, which is very suitable for the case where the valve and the pipeline are welded together. The flow direction of the medium through such valves has changed, so the flow resistance of the stop valve is higher than other valves.
Commonly used globe valves are as follows: 1) Angle globe valves; in angle globe valves, the fluid only needs to change direction once, so that the pressure drop through this valve is smaller than that of conventional structure globe valves. 2) DC type globe valve; in the DC type or Y-shaped globe valve, the flow path of the valve body and the main flow path form an oblique line, so that the degree of damage to the flow state is smaller than that of the conventional globe valve, so the pressure loss through the valve is corresponding Is too small. 3) Plunger stop valve: This type of stop valve is a variant of the conventional stop valve. In this valve, the valve flap and valve seat are usually designed based on the plunger principle. The valve flap is polished so that the plunger is connected with the valve stem, and the sealing is achieved by two elastic sealing rings sleeved on the plunger. The two elastic sealing rings are separated by a collar, and the sealing ring around the plunger is pressed firmly by the load applied to the valve cover by the valve cover nut. The elastic sealing ring can be replaced and can be made of a variety of materials. The valve is mainly used for "open" or "close", but a special form of plunger or special collar is also available to adjust the flow.
The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0 ° and 90 °. When it rotates to 90 °, the valve is fully opened.
The butterfly valve has a simple structure, small volume and light weight, and is composed of only a few parts. And only need to rotate 90 ° to quickly open and close, simple operation, and the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. There are two types of butterfly valve: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate.
Valves with metal seals generally have a longer life than valves with elastic seals, but it is difficult to achieve complete sealing. Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being limited by temperature.
If the butterfly valve is required for flow control, the main thing is to choose the size and type of the valve correctly. The structural principle of the butterfly valve is especially suitable for making large-diameter valves. Butterfly valves are not only used in general industries such as oil, gas, chemical, and water treatment, but also in cooling water systems of thermal power stations.
Commonly used butterfly valves are wafer-type butterfly valves and flange-type butterfly valves. Wafer type butterfly valve is to connect the valve between the two pipeline flanges with double-headed bolts. Flange type butterfly valve is to have a flange on the valve, and use bolts to connect the two ends of the valve to the pipeline flange.