How blowdown globe valves work and classification

A blowdown globe valve, also known as the cut-off valve, is a forced sealing valve. Today we mainly introduce the classification and principle of blowdown globe valves.

Here is the content list

l The working principle of the blowdown globe valve

l Classification of blowdown globe valves

The working principle of the blowdown globe valve

Preventing the medium from leaking along the gap between the sealing surface. The sealing pair of the blowdown globe valve is composed of the disc sealing surface and the valve seat sealing surface, and the valve stem drives the valve disc to move vertically along the center line of the valve seat. The opening height of the blowdown globe valve is small, easy to adjust the flow, the manufacturing and maintenance are convenient, and the pressure is applicable to a wide range.

Classification of blowdown globe valves

1. According to the direction of the channel, it is divided into a straight-through blowdown globe valve; DC blowdown globe valve, in the DC or Y-shaped blowdown globe valve, the flow channel of the valve body is in an oblique line with the main channel so that the degree of damage of the flow state is smaller than that of the conventional blowdown globe valve, so the pressure loss through the valve is correspondingly small; Angle blowdown globe valve, in the angle blowdown globe valve, the fluid only needs to change direction once, so that the pressure drop through this valve is smaller than that of the conventional structure of the blowdown globe valve; Plunger blowdown globe valve, this form of blowdown globe valve is a variant of conventional blowdown globe valve. The disc is polished into a plunger connected to the stem, and the seal is achieved by two elastic seals sheathed on the plunger.

2. According to the position of the thread on the stem, it is divided into upper thread stem blowdown globe valve, and the thread of the blowdown globe valve stem is outside the valve body. Its advantage is that the valve stem is not eroded by the medium, which is easy to lubricate, and this structure is more common;  The stem thread of this structure is in direct contact with the medium, is susceptible to erosion, and cannot be lubricated.

3. Needle-type blowdown globe valve. It is used for precise flow control. The disc is usually integrated into the stem and has a needle head that fits with the valve seat and is very precise. Moreover, the pitch of the stem thread of the needle-type blowdown globe valve is thinner than that of the stem thread of the general ordinary blowdown globe valve. Typically, the needle blowdown globe valve seat bore size is smaller than the pipe size. Therefore, it is usually limited to pipelines with a small nominal bore and is more used for sampling valves.

Above, we introduced the blowdown globe valve. The principle and classification of blowdown globe valves are introduced. We are a professional manufacturer of blowdown globe valves, if you have this need please contact us. We can provide you with satisfactory service.