Three classification and selection techniques for globe valves

The commonly used globe valves are as follows:

Once-through globe valve:

1) in once-through or y-shaped cut-off valve, the valve body of the flow channel and the mainstream way into a diagonal lines, so that the flow state damage than conventional globe valve is small, thus the instrument valve through the pressure loss and the corresponding small.

2) Angle stop valve: in the Angle type globe valve, the fluid only needs to be changed in one direction so that the pressure drop through this instrument valve is smaller than that of the conventional structure.

3) plunger stop valve: this type of globe valve is a variation of the conventional globe valve. In the instrument valve, the disc and seat are usually designed based on the plunger principle. The disc is connected with the stem and the seal is made by two elastic sealing rings on the plunger. The two elastic seals are separated by a ring and are pressed by the load applied to the cover by the cover nut. Elastic sealing ring can be replaced, can use a variety of materials, the instrument valve is mainly used in the “on” or “off”, but with a special form of plunger or special thimble, can also be used to adjust flow.

Globe valve selection guide:

Globe valve stem axis and seat sealing cover vertical. The valve stem opens or closes relatively short, and has very reliable cutting action, making this instrument valve very suitable for cutting or regulating and throttling service as medium.

Cut-off valve disc once in an open position, it is no longer the contact between the seat and clapper sealing surfaces, and have cut off action is very reliable, very close to the instrument valve suitable for used as medium cut or adjust and throttling.

Once stop valve is fully open, it will no longer have a contact between the seat and clapper sealing surfaces, and thus its sealing surface mechanical wear and tear is small, because most of the cut-off valve seat and valve disc is easy to repair or replace the whole instrument valve sealing components without removed from the pipeline, for the instrumentation valves and pipeline welding into one occasion is very applicable. The flow direction of the medium through the valve is changed, so the flow resistance of the stop valve is higher than that of other instrument valves.