Check valve is one kind of automatic valve, which is mainly used to prevent the back-flow of the medium.
Globe valve is one kind of industrial valve which is relying on the pressure of the valve stem to cut off the medium flow.
Now let‘s learn more about how the check valve and globe valve work, so we can get what is their difference.
1.1. How globe valve works?
The closing principle of the globe valve is to rely on the pressure of the valve stem, to force the disc sealing surface and the seat sealing surface to fit together to prevent the flow of the flow.
The globe valve only allows the medium to flow in one direction, and it is directional during installation. The globe valve’s face to face length is longer than that of the gate valve, and its fluid resistance is large, and the sealing reliability is not strong during long time operation. The globe valve can be divided into three types: straight-through globe valve, right-angle globe valve, and oblique globe valve.
1.2. What is the advantage of globe valve?
Globe valve, also known as stop valve, is widely used in pipeline to regulate and cut off the flow.
Globe valve is a very widely used valve. The reason why the globe valve is popular is that the friction between the sealing surface is small during opening and closing process, it is more durable, the stop valve’s opening height is not large, it is easy to fabricate, and convenient to maintain. It is not only suitable for medium and low pressure pipelines but also suitable for high pressure pipelines.
1.3. Test and inspection for globe valve:
During the strength test, the assembled globe valve is usually placed in the pressure test frame, the open the disc, inject the medium to the specific value, and to check whether the valve body and bonnet are sweating or leaking or not. The strength test can also be performed on single piece.
During sealing test, the valve stem of the globe valve should be in vertical state , and open the disc, inject the medium from the bottom end of the valve disc to the specific value, and check the packing and gasket. after the sealing property is qualified, close the valve disc, then check whether the other side is leaking or not.
2.1. How check valve works?
Check valve refers to the valve which automatically opens and closes the valve disc depending on the flow of the medium itself to prevent the back-flow of the medium. Check valve is also known as non-return valve, one-way valve, back-pressure valve.
The check valve can work automatically. Under the action of fluid pressure which flows in one direction, the valve plate opens; when the medium flows in the opposite direction, the fluid pressure and the self-weight of valve plate close the valve plate to the valve seat to cut off the flow.
2.2. What is the advantage of check valve?
Check valve is one automatic valve whose main function is to prevent the back-flow of the medium, the reverse rotation of the pump, and the driving motor, and the discharge of the medium in the container.
Check valve can be mainly divided into lift type check valve, swing check valve, wafer butterfly check valve.
2.3. Test and inspection for check valve:
Testing state for check valve: the axis of the valve disc of lift check valve should be in a position perpendicular to the horizontal; the axis of the channel of the swing check valve and the axis of the disc should be in a position approximately parallel to the horizontal line.
During strength test, the test medium is introduced from the inlet to the specified value, and the other end is closed, if there is no leaking in valve body and bonnet, it is qualified.
For sealing test, introduce the medium from the outlet, to check the sealing surface in the inlet end, if there is no leakage in packing and gasket, it is qualified.
For information about the check valve and globe valves, please visit our other articles:
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