Differences Between Ball Valves and Gate Valves
There are many kinds of valves in our daily life. However, the most common valves are the ball valve and gate valve. Before buying them, we need to know about the use and function of them. Then, what are the differences between them? How to choose good quality ball valves and gate valves? Here we summarize some of the knowledge of the ball valve and gate valve to tell you the differences between ball valves and gate valves. Which one is better?
Differences between ball valves and gate valves
1. The difference in the spool valve
A.The ball valve is the core to the sphere. Because of its structure, under the condition of high pressure, especially the closed state, the valve ball is fixed. The valve upper stem and lower fulcrum decompose the part from the medium pressure, so the valve ball is not downstream migration. The downstream seat stress is relatively small, so the valve in the action to overcome the friction is small. The seat wear is small. The service life of the valve is long, especially for the valve of regular action, and this structure is more suitable.
B. The spool of the gate valve is a wedge disc or parallel disc. The lower part has no supporting shaft. Under high voltage application, when the valve closed, the valve plate is under great pressure from the media. Because of its planar structure of valve plate, it is made all the medium pressure effect on valve plate. At the same time, the valve plate is in pressure downstream seat. There is too much pressure on the vertical face of the valve plate, which makes the valve plate wedge or parallel double ram. There will be certain deformation. The valve in the opening of the need can overcome the great friction, and the seat wear print the valve life is short.
2. The difference in the seat structure
The valve seat has a spring inside, and the sealing design of the valve seat makes it difficult for dregs in the media to enter the valve seat. The valve seat under the action of the spring long-term contact with the valve ball. When the valve acts, the valve seat has a certain role of the scraper. It can be attached to the dregs on the spool after long-term operation. It can ensure the valve sealing performance for a long time, especially in high temperature and high pressure applications. The valve seat, valve body, valve ball material, the spring structure of the valve seat have the same thermal expansion coefficient of material. Therefore, when the valve is closed, the huge temperature difference and temperature drop. It will not affect the action of the valve. The valve will not produce the phenomenon of death. The seat of gate valves is very narrow in high temperature applications. Because the medium does not flow, the temperature drops when the valve is closed. The seat will contract. It will result in a lot of pressure on the valve plate. When the valve is opened again, a great torque is needed to overcome the compression force, which will cause great damage to the seat and affect the life of the seat. Thus, it affects the service life of the valve. In addition, when the valve is closed. It will bring a lot of impact and noise to the valve due to the weight of the gate itself.
3. The difference in stroke
The stroke of ball valves is an angular stroke, so the installation space is small, and the height is low. The stroke of gate valves is a straight stroke, so the installation space is large, and the height is high.
4. The difference between the executive organs
Due to the design of the fixed ball, its opening and closing torque value is small and the corresponding actuator is small. Due to the valve plate on the seat of the compression force, the actuator is large because overcoming this friction requires great torque.
5. The difference in medium flow
The medium flow of ball valves is double flow. There is no installation flow problem on site. Gate valves are generally single flow.
6. The difference in maintenance
Generally, they need no maintenance, especially on the ball and seat. Due to low wear, generally there is no need to replace within 5 years. Regular maintenance is required for gate valves due to the large seat wear.
Differences between ball valves and gate valves
1. The difference in the spool valve
A.The ball valve is the core to the sphere. Because of its structure, under the condition of high pressure, especially the closed state, the valve ball is fixed. The valve upper stem and lower fulcrum decompose the part from the medium pressure, so the valve ball is not downstream migration. The downstream seat stress is relatively small, so the valve in the action to overcome the friction is small. The seat wear is small. The service life of the valve is long, especially for the valve of regular action, and this structure is more suitable.
B. The spool of the gate valve is a wedge disc or parallel disc. The lower part has no supporting shaft. Under high voltage application, when the valve closed, the valve plate is under great pressure from the media. Because of its planar structure of valve plate, it is made all the medium pressure effect on valve plate. At the same time, the valve plate is in pressure downstream seat. There is too much pressure on the vertical face of the valve plate, which makes the valve plate wedge or parallel double ram. There will be certain deformation. The valve in the opening of the need can overcome the great friction, and the seat wear print the valve life is short.
2. The difference in the seat structure
The valve seat has a spring inside, and the sealing design of the valve seat makes it difficult for dregs in the media to enter the valve seat. The valve seat under the action of the spring long-term contact with the valve ball. When the valve acts, the valve seat has a certain role of the scraper. It can be attached to the dregs on the spool after long-term operation. It can ensure the valve sealing performance for a long time, especially in high temperature and high pressure applications. The valve seat, valve body, valve ball material, the spring structure of the valve seat have the same thermal expansion coefficient of material. Therefore, when the valve is closed, the huge temperature difference and temperature drop. It will not affect the action of the valve. The valve will not produce the phenomenon of death. The seat of gate valves is very narrow in high temperature applications. Because the medium does not flow, the temperature drops when the valve is closed. The seat will contract. It will result in a lot of pressure on the valve plate. When the valve is opened again, a great torque is needed to overcome the compression force, which will cause great damage to the seat and affect the life of the seat. Thus, it affects the service life of the valve. In addition, when the valve is closed. It will bring a lot of impact and noise to the valve due to the weight of the gate itself.
3. The difference in stroke
The stroke of ball valves is an angular stroke, so the installation space is small, and the height is low. The stroke of gate valves is a straight stroke, so the installation space is large, and the height is high.
4. The difference between the executive organs
Due to the design of the fixed ball, its opening and closing torque value is small and the corresponding actuator is small. Due to the valve plate on the seat of the compression force, the actuator is large because overcoming this friction requires great torque.
5. The difference in medium flow
The medium flow of ball valves is double flow. There is no installation flow problem on site. Gate valves are generally single flow.
6. The difference in maintenance
Generally, they need no maintenance, especially on the ball and seat. Due to low wear, generally there is no need to replace within 5 years. Regular maintenance is required for gate valves due to the large seat wear.
