Notes On Selecting Brass Ball Valve

Usually ball valves usually use rubber, nylon and PTFE as the seat sealing ring material, so their use temperature is improperly criticized by certain sealants, or the product is produced on the sealing surface, and the valve plug cannot rotate in the valve body At this time, the valve must be repaired.

Cylindrical plug valve is equipped with a PTFE sleeve and valve plug seal in the valve body, it is pressed in the valve body with a compression nut, and the sealing force is achieved by the expansion force of the valve cold on the PTFE gold Jane

1. Conical plug valve

(1) Tightened conical chill valve
This type of plug valve has no packing. The sealing between the plug and the sealing surface of the valve body is achieved by tightening the nut under the plug. It is generally used in low-pressure applications where the nominal pressure is PN <0. 6MPa. The shape of the conical rotary cold valve connected with a small U-diameter internal thread is shown in the figure. The leakage gap between the sealing pairs of the conical plug valve can be adjusted by forcing the valve plug deeper into the seat. When the valve plug is in close contact with the valve body, the valve plug can still be rotated, or it can be lifted from the valve seat and rotated by 90 ° before the rotation. Iflj is pressed and sealed.

(2) Packed conical plug valve
Conical stopcock as. Packed conical plug valves have packing in the valve body, and the sealing surface of the valve plug and valve body is sealed by compressing the packing. This packing conical chill valve has better sealing performance and is used in the occasions with nominal pressure PN = 1. 0?〗. 6MPa. The screw under the valve body is used to adjust the tightness between the valve plug and the valve body.

(3) PTFE sleeve simple seal conical plug valve
In order to overcome the lubrication and maintenance problems of plug valves, this type of Teflon sleeve simple seal conical plug valve was developed. In this valve, the valve plug rotates inside a PTFE sleeve embedded in the valve body, and the PTFE sleeve prevents the valve from sticking. However, due to the large sealing area and high sealing stress, the operating torque is still large. On the other hand, due to the large sealing area, even if there is some damage on the sealing surface h, it can still better prevent leakage, therefore, this valve is durable.