The difference between plunger valve and globe valve

he closure of the plunger valve is composed of a stainless steel plunger, two elastic sealing rings on top and bottom, and a metal partition frame. The sealing effect is achieved by the close fit between the plunger and the sealing ring. The plunger is inserted into the two sealing rings, and the sealing area is much larger than that of a regular globe valve; When opening and closing the plunger valve, the plunger moves slowly in the sealing ring, and the contact surface is almost not worn. When closed, the plunger is inserted into the lower sealing ring, cutting off the flow passage; When opened, although the plunger detaches from the lower sealing ring, it still hides inside the upper sealing ring, maintaining isolation from the outside and preventing leakage. Due to the surface of the plunger being processed by a high-precision cylindrical grinder. The sealing ring adopts a non-toxic new sealing material with strong elasticity and high wear resistance, so the sealing is reliable and durable. This improves the service life of the plunger valve.

1. Plunger valve is composed of valve body, valve cover, valve stem, plunger, hole frame, sealing ring, handwheel and other parts. When the handwheel rotates, the valve stem drives the plunger to move up and down in the middle of the hole frame to complete the opening and closing functions of the valve. The opening and closing component of a globe valve is a plug shaped valve disc, with a flat or conical sealing surface. The valve disc moves in a straight line along the centerline of the fluid.

2. The closure of the plunger valve is composed of a stainless steel plunger, two elastic sealing rings on top and bottom, and a metal partition frame. The sealing effect is achieved by the close fit between the plunger and the sealing ring. The plunger is inserted into the two sealing rings, and the sealing area is much larger than that of a regular globe valve; When opening and closing the plunger valve, the plunger moves slowly in the sealing ring, and the contact surface is almost not worn. When closed, the plunger is inserted into the lower sealing ring, cutting off the flow passage; When opened, although the plunger detaches from the lower sealing ring, it still hides inside the upper sealing ring, maintaining isolation from the outside and preventing leakage.

3. Globe valves belong to forced sealing valves, so when the valve is closed, pressure must be applied to the valve disc to force the sealing surface not to leak. When the medium enters the valve from below the valve disc, the resistance that needs to be overcome by the operating force is the frictional force between the valve stem and packing and the thrust generated by the pressure of the medium. The force to close the valve is greater than the force to open it, so the diameter of the valve stem should be larger, otherwise it will cause the valve stem to bend.

4. Globe valves have the following advantages: simple structure, convenient manufacturing and maintenance, small working stroke, and short opening and closing time. Good sealing performance, low friction between sealing surfaces, and long service life. The disadvantages of a shut-off valve are as follows: high fluid resistance and high force required for opening and closing. Not suitable for media with particles, high viscosity, and easy coking. Poor regulation performance. The advantages of a plunger valve have been mentioned above, but its biggest disadvantage is its slow opening and closing speed.