Introduction of Bellows Seal Gate Valve——HERO VALVE

The bellows gate valve is the most widely used valve at present. Due to the small opening and closing process of the friction of the sealing surface, it is durable, the opening height is not large, and it is convenient to manufacture and maintain. The sealing principle is to rely on the pressure of the valve stem to make the valve sealing surface and the valve seat sealing surface close to prevent the flow of medium.

The bellows gate valve only allows one-way medium to flow, and is directional during installation. Its structural length is greater than the gate valve, the fluid resistance is large, long-term operation, the sealing reliability is not strong.

Bellows gate valves are divided into three categories: straight-through, right-angle and direct-flow oblique globe valves.

When the bellows gate valve is opened, the opening height of the valve flap is 25% to 30% of the nominal diameter. Therefore, the total opening position should be determined by the stroke of the disc.

(1) The installation position, height and direction of the entrance and exit must meet the design requirements and the connection is firm.

(2) The handles of various manual valves installed on thermal insulation pipes shall not be downward.

(3) Check before installation. The nameplate of the valve should comply with the current national standard GB12220. For valves with working pressure greater than 1.0mpa and cut off on the main pipe, the strength and tightness test shall be carried out before installation. When the strength test, the test pressure is twice the nominal pressure, the duration is not less than 5 minutes, the valve housing and packaging should be qualified without leakage. The test pressure is twice the nominal pressure. The test pressure should meet the GB50243 standard during the test.

1. Simple structure, easy to manufacture and maintain.

2. The working schedule is small, and the opening and closing time is short.

3. Good sealing performance, small friction between sealing surfaces and long service life.

The disadvantages of bellows gate valves are as follows:

1. The fluid resistance is large, and the force required for opening and closing is large.

2. Not suitable for media with particles, high viscosity, and easy coking.

3. Poor adjustment performance.

The type of bellows gate valve can be divided into external thread and internal thread according to the thread position. According to the flow direction of the medium, there are straight-through, direct current and angle. The shut-off valve is divided into sealed valve and bellows sealed shut-off valve according to the sealing form.

Bellows gate valve installation and maintenance should pay attention to the following:

1. Handwheel and handle operation can be installed anywhere in the pipeline.

2. The handwheel, handle and drive mechanism must not be hoisted.

3. The flow direction of the medium must be consistent with the direction of the arrow shown in the valve body.

——CHINA · HERO VALVE