1) Flange stop valve: in DC or Y-shaped stop valve, the flow passage of valve body is inclined with the main channel, so the damage degree of flow state is smaller than that of conventional stop valve, so the pressure loss through instrument valve is also relatively small.

The common stop valves are as follows:

1) DC stop valve: in DC or Y-shaped stop valve, the flow passage of valve body is inclined with the main channel, so the damage degree of flow state is smaller than that of conventional stop valve, so the pressure loss through instrument valve is also relatively small.

2) Angle stop valve: in angle stop valve, the fluid only needs to change the direction once, so that the pressure drop through the instrument valve is smaller than that of the conventional stop valve.

3) Plunger type stop valve: this type of stop valve is a change of conventional stop valve. In this instrument valve, the disc and seat are usually designed based on the principle of plunger. The disc is polished into a column plug connected with the valve stem. The seal is realized by two elastic sealing rings which are set on the plunger. The two elastic sealing rings are separated by a ferrule and the sealing rings around the plunger are firmly pressed by the load applied to the bonnet by the bonnet nut. Elastic sealing ring can be replaced and can be made of various materials. The instrument valve is mainly used for "open" or "off", but it is equipped with special plunger or special collar, and can also be used to adjust flow.

Guide for selection of flange stop valve

The stem axis of the stop valve is perpendicular to the sealing surface of the valve seat. The valve stem has a relatively short open or closed stroke and has a very reliable cut-off action, which makes this kind of instrument valve very suitable for cutting or adjusting and throttling as a medium. Once the disc of the stop valve is in open condition, the valve seat and disc sealing surface will no longer contact, and have a very reliable cut-off action. It is suitable for cutting off or adjusting and throttling of the medium. Once the stop valve is in open state, there is no contact between its seat and disc sealing surface, so its sealing surface has less mechanical wear. Since most of the valve seats and disc are easy to repair or replace the sealing elements, it is not necessary to remove the whole instrument valve from the pipeline, which is very suitable for the welding of instrument valve and pipeline. The flow direction of medium passing through such instrument valve has changed, so the flow resistance of stop valve is higher than that of other instrument valves.