Gate valve for large diameter, ball valve for small diameter.
Second, what is the difference between gate valve and ball valve
1. Difference in valve core structure
The valve core of the ball valve is a ball. Because of its fixed structure, the valve ball is fixed in the case of high voltage, especially when it is closed, and a part of the upper seat and the lower support shaft are dissolved. Due to the working pressure of the material, the valve ball does not deviate to the middle and downstream, so the working pressure borne by the middle and downstream valve seats is relatively small.
Therefore, the sliding friction of the valve in the posture is small, the damage to the valve seat is small, and the service life of the valve is long, especially for the valve with frequent posture, this type of structure is more suitable.
The valve core of the gate valve is a wedge-shaped valve plate or this parallel face valve plate. There is no fulcrum below it. Therefore, when the valve is used under high pressure and is turned off, the valve plate bears a large degree of working pressure derived from the material, and because of its plan view of the valve plate structure, all the material working pressure is simultaneously effective in the valve. If the valve plate is on the valve plate, the valve plate will be pressed firmly to the middle and downstream valve seats (at the same time, the excessive burden acts on the vertical surface of the valve plate, which will make the valve plate, whether it is a wedge type or a parallel double gate valve, all There will be a certain deformation), then the valve needs to get rid of a large sliding friction when it is opened, and the damage of the valve seat prints the short cycle of the valve.
2. Difference in valve seat structure
The internal structure of the valve seat of the ball valve has a torsion spring, and the sealing design of the valve seat position makes it difficult for the residue in the material to enter the valve seat position. The valve seat is in contact with the valve ball for a long time under the effect of the spring sheet, so when the valve is in the valve position, the valve seat has a certain scraper function, which can scrape off the residue adhering to the angle valve after long-term operation. Therefore, the sealing property of the valve can be ensured for a long period of time.
Especially in the application of ultra-high pressure and high temperature, because the material of the valve seat, oil circuit board and valve ball is selected with the same linear expansion coefficient, there is also a valve seat with a torsion spring structure, so when the valve is closed, the The temperature difference and the decrease in Butterfly handle CQ thread brass balll valve air temperature will not harm the posture of the valve, and the valve will not cause the wheel to lock.
The valve seat of the gate valve is narrow. When the valve is closed at high temperature, the temperature will decrease because the material is not circulated, so the valve seat will be tightened, which will cause a very large clamping force to the valve plate.
When the valve is opened again, a large torque must be used to get rid of this kind of clamping force, which will cause great damage to the valve seat and endanger the service life of the valve seat. This in turn affects the service life of the valve. In addition, due to the weight of the gate valve itself when the valve is closed, it will generate a large impact force on the valve and cause a lot of noise.
3. Differences in itinerary arrangements
The stroke of the ball valve is arranged as an angular stroke, so the installation space is small and the relative height is low. The stroke arrangement of the gate valve is a straight stroke, so the installation indoor space is large and the relative height is high.
4. The difference between actuators
Because of the fixed fixed ball design, the torque value of its opening and closing is small, so the actuator is correspondingly small. Because the clamping force of the valve plate on the valve seat is large, it takes a huge torque to get rid of such large sliding friction, and the actuator is equipped with a large amount.
5. The difference between material inflow
The ball valve has a dual flow direction, and there is no installation inflow problem on the spot. Gate valves are generally unidirectional.
6. The difference in maintenance
Generally, no maintenance is required, especially the valve ball and valve seat, because the damage is small, generally do not need to be replaced within 5 years. The gate valve needs maintenance due to the large damage to the valve seat.