Difference Between Gate Valve and Ball Valve

The valve core of gate valve and ball vave

Ball Valve

The valve core of the ball valve is a ball. Because of its fixed ball structure, the valve is fixed under the condition of high pressure, especially when it is closed. The upper stem and the lower support shaft decompose part of the pressure from the medium, so the ball does not shift to the downstream, so the pressure on the downstream valve seat is relatively small, so the friction force that the valve overcomes when it acts is small, so the valve seat is ground. Small damage, the long service life of the valve, especially for frequently operated valves, this structure is more suitable.

Gate Valve

The core of the gate valve is a wedge valve plate or parallel valve plate. There is no supporting shaft at its lower part. Therefore, when the valve is in the high-pressure application and in the closed state, the valve plate bears a great pressure from the medium. Because of the flat gate valve plate structure, all the medium pressure acts on the valve plate at the same time, the valve plate will be dead pressed to the downstream valve seat (at the same time, the excessive pressure acts on the vertical surface of the valve plate, making the valve plate whether wedge-shaped or parallel double ram. There will be some deformation), so the valve needs to overcome great friction when it is opened, so the life of the valve printed by the wear of the valve seat is short.

Valve seat of gate valve and ball vave

There is a spring in the valve seat of the ball valve, and the sealing design of the valve seat makes it difficult for the dregs in the medium to enter the valve seat. The valve seat contacts with the valve ball for a long time under the action of spring, so when the valve acts, the valve seat has a certain scraper function, which can scrape off the residue attached to the valve core after long-term operation, so the sealing performance of the valve can be guaranteed for a long time. Especially in the application of high temperature and high pressure, because the materials of valve seat, valve body and valve ball are selected with the same thermal expansion coefficient and the valve seat with spring structure, when the valve is closed, the huge temperature difference and temperature drop will not affect the action of the valve, and the valve will not be locked. The valve seat is very narrow. In high-temperature application, when the valve is closed because the medium is not circulating, the temperature will drop, so the valve seat will be tightened, which will produce a great pressing force on the valve plate. When the valve is opened again, a large torque is needed to overcome this pressing force, which will cause great damage to the valve seat and affect the service life of the valve seat. Thus, the service life of the valve is affected. In addition, due to the self-weight of the gate itself when the valve is closed, it will bring great impact force and noise to the valve.

Itinerary of gate valve and ball vave

Ball Valve

The stroke of the ball valve is angle stroke, so the installation space is small and the height is low.

Gate Valve

The stroke of the gate valve is a straight stroke, so the installation space is large and the height is high.

Actuator of gate valve and ball vave

Due to the design of the trunnion ball, the torque value of its opening and closing is small, so the corresponding actuator is small. Because the valve plate has a large pressing force on the valve seat, it needs a large torque to overcome this large friction, and the actuator is equipped with a large amount of torque.

Medium flow direction of gate valve and ball vave

Double flow direction, no installation flow direction problem on site.
Generally, it is a single flow direction.

Service life of gate valve and ball vave

The ball valve has a longer service life, while the gate valve’s service life is relatively short.

Maintenance of gate valve and ball vave

Ball Valve

The ball valve generally does not need maintenance, especially the ball and valve seat. Due to the small wear, it does not need to be replaced within 5 years.