Ball valve reliable in sealing and low in opening-closing torque

Abstract

The invention relates to a valve, in particular to a ball valve reliable in sealing and low in opening-closing torque. The ball valve comprises a valve body with a valve cavity, a ball positioned in the valve cavity, a valve rod in linkage with the ball and a valve seat sealing mechanism arranged between the valve body and the ball. A valve seat component and an annular valve seat component cavity are in airtight fit to form a structure similar to a piston. A pre-tensioning elastic part and a three-way reversing valve are arranged on one side, opposite to the ball, of the valve body. The three-way reversing valve is used for controlling pressure applied to the ball by the valve seat component under different conditions and an operating air source of a pneumatic device to realize the fact that when the valve is closed, the pressure applied to the ball by the valve seat component is large, the sealing performance is fine, and when the valve is opened, the pressure applied to the ball by the valve seat component is small. Therefore, the opening power is low, a ball sealing face is less prone to damage during opening, and the service life of the ball valve is prolonged.

Description

technical field [0001] The present invention relates to a valve, more specifically, it relates to a ball valve with reliable sealing and small opening and closing torque. Background technique [0002] Pneumatic ball valve is a very widely used valve. Its structure usually includes a valve body with a valve cavity, a ball placed inside the valve cavity, a valve stem linked to the ball, and a valve seat placed between the valve body and the ball. The valve stem part is exposed outside the valve body, and the valve body is provided with an operating drive device for driving the valve stem to rotate. The operating drive device drives the valve stem to drive the 90° rotation of the ball to make the ball valve switch between open and close. Seat sealing structure and force analysis of traditional trunnion ball valve figure 1 as shown, figure 1 Among them, 1A is the sphere, 2A is the valve seat sealing ring, 3A is the valve seat, 4A is the spring, 5A is the valve body, 6A is the ...

AI Technical Summary

Problems solved by technology

However, the greater the force of the medium acting on the back of the valve seat, the greater the bonding force between the ball and the sealing ring of the valve seat, and the greater the friction between them, the greater the operating force is required to open the valve, or more large drive mechanism

In addition, when the sealing force between the ball and the sealing ring of the valve seat is too large, it is easy to cause damage to the sealing surface of the valve when the valve is opened, especially when the medium contains solid particles, it is more likely to be damaged

In short, from the perspective of improving the sealing performance of the valve seat, it is necessary to increase the thrust of the medium behind the valve seat, but from the perspective of reducing the opening and closing torque of the valve and preventing damage to the sealing surface, it is necessary to reduce the thrust of the medium behind the valve seat, Therefore, this is a contradiction that has plagued the design of ball valves for a long time.

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