Author: Site Editor Publish Time: 2020-08-27 Origin: Site
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.
List of content for this article：
1. The feature of ball valve,
2. The instructions for globe valve,
3. Gate valve's application and its' operating ways.
The feature of ball valve
The ball valve only needs to be rotated 90 degrees and a small turning torque to close tightly. The fully equal valve body cavity provides a small, straight-through flow path for the medium. Ball valves are generally considered to be the most suitable for opening and closing, but recent developments have designed ball valves to throttling and control flow. The main features of the ball valve are its compact structure, easy operation and maintenance, suitable for general working media such as water, solvent, acid and natural gas, and also suitable for medium with harsh working conditions such as oxygen, hydrogen peroxide, methane and ethylene. The ball valve body may be integral or combined.
The instructions for globe valve
The globe valve and stem axis are perpendicular to the seat sealing surface. The valve stem has a relatively short opening or closing stroke and a very reliable shut-off action, making this valve ideal for use as a medium for cutting or mediating and throttling. Once the valve flap of the globe valve is in the open state, once its seat and disc are open, its seat and the sealing surface of the disc are no longer in contact, and have a very reliable cutting action. The valves are ideal for use as a medium for cutting or regulating and throttling.
Once the globe valve is open, there is no contact between its seat and the disc sealing surface, so its sealing surface is less mechanically worn, because the valve seat and disc of most globe valves are easier to repair or replace. It is not necessary to remove the entire valve from the pipeline when sealing the components, which is suitable for the case where the valve and the pipeline are welded together. The flow direction of the medium as it passes through such a valve changes, so the flow resistance of the globe valve is higher than other valves.
Gate valve's application and its' operating ways.
The gate valve is used as a cut-off medium, and the whole flow is straight through when fully open, at which time the pressure loss of the medium operation is minimized. Gate valves are generally suitable for applications that do not require frequent opening and closing, but also keep the shutter fully open or fully closed. Not suitable for use as an adjustment or throttling. For high-speed flowing media, the gate can cause vibration of the gate under partial opening conditions, and the vibration may damage the sealing surface of the gate and the valve seat, and the throttling will cause the ram to be eroded by the medium. The main difference in terms of structural form of the sealing element used. Depending on the form of the sealing element, the gate valves are often divided into several different types.
In addition, the manual valve is the most basic drive type of valve. It consists of a hand wheel, a handle or a wrench for direct drive and a drive through the transmission. When the valve's starting torque is large, it can be driven by gear or turbine drive for the purpose of omission. The gear transmission is divided into a spur gear transmission and a bevel gear transmission. The gear rotation reduction ratio is small, suitable for gate valves and globe valves. The turbine transmission has a large deceleration and is suitable for cocks and ball valves.