How does the stop valve work?

Shut off valve, also known as shut-off valve, is one of the most widely used valves. The reason why it is widely popular is that the friction force between the sealing surfaces is small in the opening and closing process, relatively durable, small in opening height, easy to manufacture and easy to maintain. It is not only suitable for medium and low pressure, but also suitable for high pressure. The closing principle of the globe valve is that the sealing surface of the valve disc and the valve seat are closely connected by the pressure of the valve rod to prevent the medium from flowing. China's "three modernizations to" once stipulated that the flow direction of the stop valve should be from top to bottom, so the installation has directionality. The structure length of the stop valve is longer than that of the gate valve. At the same time, the fluid resistance is large, and the sealing reliability is not strong in long-term operation.

As one of the most important block valves, globe valve plays an important role in the field of aerospace. As an important component of aerospace equipment, the stop valve realizes the functions of medium transportation, cut-off and adjustment, and its sealing performance directly affects the safe and reliable operation of space equipment. The research on the influencing factors and rules of sealing characteristics of typical globe valves is of guiding significance to the structural design of valve sealing pairs, so as to improve the sealing performance and reliability of valves.

Working principle and characteristics of stop valve

The valve plays an important role in cutting off and throttling the medium in the pipeline where it is located. As an extremely important cut-off valve, the stop valve is sealed by applying torque to the valve stem, and the valve stem applies pressure to the valve disc in the axial direction, so that the sealing surface of the valve disc and the sealing surface of the valve seat are closely connected, and the leakage of the medium along the gap between the sealing faces is prevented.

The sealing pair of the globe valve consists of the sealing surface of the disc and the sealing surface of the valve seat. The valve stem drives the valve disc to move vertically along the center line of the valve seat. In the process of opening and closing, the stop valve has small opening height, easy flow adjustment, convenient manufacturing and maintenance, and wide range of pressure application.

Compared with the alarm valve, another commonly used block valve in industrial production, the stop valve is simpler in structure and easier to manufacture and maintain. In terms of service life, the sealing surface of the stop valve is not easy to wear and scratch_ There is no relative sliding between the seat sealing surfaces, so the wear and scratch of the sealing surface are small, so the service life of the sealing pair is improved. During the full closing process, the valve disc stroke of the stop valve is small, and its height is smaller than that of the alarm valve. The disadvantage of the stop valve is that the opening and closing torque is large and it is difficult to realize fast opening and closing. Because the flow channel in the valve body is relatively tortuous and the flow resistance is large, the loss of fluid power in the pipeline is large.