What are the classifications of marine valves

1. according to the channel direction of the stop valve, it is divided into:

1) Straight through stop valve

2) Once through stop valve: in a once through or Y-shaped stop valve, the flow path 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) Angle stop valve: in the angle stop valve, the fluid only needs to change the direction once, so that the pressure drop through the valve is smaller than that of the conventional stop valve.

4) Plunger type stop valve: this type of stop valve is a variant of the conventional stop valve. In this valve, the valve disc and valve seat are 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 can be 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 regulate the flow.

2. according to the position of the thread on the stop valve stem, it can be divided into:

1) Upper thread stem stop valve: the thread of the stop valve stem is outside the valve body. The utility model has the advantages that the valve rod is not eroded by the medium and is easy to lubricate. This structure is widely used.

2) Lower threaded stem stop valve: the thread of the stop valve stem is in the valve body. The thread of the valve rod with this structure is in direct contact with the medium, which is easy to be eroded and cannot be lubricated. This structure is used in places with small caliber and low temperature.