Ball valves are evolved from plug valves. It has the same rotation of 90 degrees, except that the plug body is a sphere with a circular through hole or its axis. The ratio of the spherical surface to the passage opening should be such that when the ball is rotated 90 degrees, the spherical surface should be entirely present at the inlet and outlet to intercept the flow.

Principles of selecting gate valve, the gate valve should be the first choice when shut-off valves need to be used for pipelines. Normally, globe valves are a little bit expensive than gate valves, but a little cheaper than metal-sealed ball valves, seldom used as shut-off valves for main pipelines.

Common manual valves, including ball valve, gate valve, globe valve, butterfly valve, plug valve, etc., are the most widely used valves. Their handwheels or handles are designed according to ordinary manpower, taking into account the strength of the sealing surface and the required closing force.

The gate valve is a valve that moves the shutter closure member in the vertical direction of the centerline of the passage. Generally, it consists of valve body, valve seat, valve stem, gate, valve cover and sealing ring.

Valve daily maintenance is very importance, following are some instructions for valve daily maintenance.Doing these tasks well is believed to be very helpful for prolonging the service life of the valve, and it can also reduce a lot of unnecessary troubles.

In recent years, with the continuous improvement of China's comprehensive national strength, the development of China's marine industry has also achieved rapid progress. In this context, the shipbuilding industry has drawn much attention.

In our current valve on the market, in addition to low pressure valve acceptable to the international market level, the high-pressure valve still needs to rely on imports. Continued good macroeconomic situation, the valve industry most of the production and sales targets are maintained rapid growth.

Due to the relatively large variety of valves used in the marine's pipelines, this creates difficulties in preparing and revising the appropriate standards for valves. Another aspect is that the use of valves in current marine pipelines in China is mainly based on manual valves such as a globe valve and gate valve. Such industrial valves are still relatively insufficient in terms of weight, volume, and sealing.

The opening and closing member of the gate valve is a gate. The direction of movement of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully open and fully closed, and cannot be adjusted and throttled.

The professional maintenance work of the gate valve before and after the installation plays a vital role in the service of the gate valve. The correct and orderly maintenance will protect the gate valve, make the gate valve function properly and extend the gate valve life.