Correct selection method I of the hottest valve

Correct selection method of valve (I)

the gate valve is used as the cut-off medium. When it is fully opened, the whole flow is straight through. At this time, the pressure loss of medium operation is the smallest. Gate valves are usually suitable for working conditions that do not require frequent opening and closing, and keep the gate fully open or fully closed. It is not suitable for use as regulation or throttling. For the high-speed flow medium, the ram can cause the vibration of the gate when it is partially opened, and the vibration may damage the sealing surface of the ram and valve seat of the development trend of Jinan testing machine, and throttling will cause the ram to be eroded by the medium. From the structural form, the main difference is the form of sealing elements. According to the form of sealing elements, gate valves are often divided into several different types. A. insufficient lubrication between ball screw and motor shaft hole or dirt blocking; Types, such as wedge gate valve, parallel gate valve, parallel double gate valve, wedge double gate valve, etc. The most commonly used forms of wedge flame retardants are high molecular synthetic booster gate valves and parallel gate valves

stop valve

the stem axis of the stop valve is perpendicular to the sealing surface of the valve seat. The opening or closing stroke of the valve rod is relatively short, and it has a very reliable cut-off action, which makes this valve very suitable for cutting off or adjusting the medium and throttling. Once the disc of the stop valve is in the open state, its seat and the sealing surface of the disc will no longer be in contact, and has a very reliable cut-off action. This kind of valve is very suitable for cutting off or adjusting the medium and throttling

once the stop valve is in the open state, there is no contact between its valve seat and the sealing surface of the valve disc, so its sealing surface has less mechanical wear. Because most of the valve seats and valve discs of the stop valve are relatively easy to repair or replace the sealing elements, there is no need to remove the whole valve from the pipeline, which is very suitable for the occasions where the valve and pipeline are welded together. When the medium passes through such valves, the flow direction changes, so the flow resistance of the stop valve is higher than that of other valves

there are several commonly used stop valves: 1) angle stop valve; In the angle stop valve, the fluid only needs to change the direction once, so that the pressure drop through this valve is smaller than that of the conventional stop valve. 2) DC stop valve; In the once through or Y-shaped stop valve, the flow passage of the valve body forms an oblique line with the main flow path, so the damage degree of the flow state is smaller than that of the conventional stop valve, so the pressure loss through the valve is correspondingly smaller. 3) Plunger stop valve: this type of stop valve is a variant of the conventional stop valve. In this valve, the disc and seat are usually designed based on the plunger principle. The valve disc is polished into a column plug and connected with the valve rod. The sealing is realized 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 firmly pressed by the load applied on the bonnet by the bonnet nut. The elastic seal ring can be replaced and made of various materials. The valve is mainly used for "opening" or "closing", but it is equipped with a special plunger or special collar, which can also be used to adjust the flow

butterfly valve

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 ° ~90 °. When it rotates to 90 °, the valve is fully open

butterfly valve is simple in structure, small in size and light in weight. It is only composed of a few parts. Moreover, it can be opened and closed quickly by rotating 90 °, which is simple to operate. At the same time, 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 only toxic and harmful organic synthetic solvent to replace when the medium flows through the valve body. Therefore, the pressure drop generated through the valve is very small, so it has good flow control characteristics. The butterfly valve has two sealing types: elastic seal and metal seal. For elastic sealing valves, 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 service life than those with elastic seals, but it is difficult to achieve complete sealing. Metal seal can adapt to higher working temperature, while elastic seal has the defect of being limited by temperature