The working principle of the globe valve features and classification

Author:     Published time:2016-10-10 16:44     Reading times:443    

Working principle of globe valve:

    The globe valve is a plug-shaped opening and closing the valve-shaped valve, sealing surface was flat or cone, the valve along the center line of the fluid for linear motion. The movement of the valve stem in the form of a lift rod (stem up and down, the hand wheel does not lift), but also lift the rotating rod (hand wheel and stem rotation with the lift, the nut is located on the valve body). The globe valve is only applicable to fully open and fully closed, not for adjustment and throttling.

Globe valve is a mandatory sealed valve, so the valve is closed, the valve must be applied pressure to force the sealing surface does not leak. When the media from the valve below the valve body into the body, the operating force to overcome the resistance is the stem and filler friction and pressure generated by the medium of the thrust of the force than the valve to open the valve force, so the valve diameter of the rod to be large, or it will occur stem top bend of the fault. In recent years, since the emergence of self-sealing valve, the flow direction of the valve to change from the top of the valve into the valve chamber, then the pressure in the medium under the force off the valve is small, and open the valve force, stem The diameter can be reduced accordingly. At the same time, the role of the media, this form of the valve is more stringent. Valve opening, the valve opening height, nominal diameter of 25% to 30%, the flow has reached the maximum, said the valve has reached the fully open position. So globe valve fully open position, the valve should be determined by the stroke.

 

The globe valve has the following advantages:

     1, Simple structure, manufacturing and maintenance more convenient.

     2, The working stroke is small, opening and closing time is short.

     3, Good sealing, sealing surface friction between the small, long life.

Disadvantages of globe valves are as follows:

     1, The fluid resistance, open and close the required force greater.

     2, It does not apply to particles with a large viscosity, easy to coke of the media.

     3, Poor regulation performance.

Globe valve classification:

      Type of globe valve stem thread according to the location of sub-threaded, internal thread type. According to the flow of media points, there are straight-through, DC and angle. Globe valve in the form of sub-points, there are packing sealed globe valve and bellows sealed globe valve.

  Globe valve installation and maintenance should note the following:

     1, Hand wheel, handle the operation of the globe valve can be installed in any position on the pipeline.

     2, Hand wheel, handle and transmission, is not allowed to use for lifting.

     3, The direction of flow of media should be consistent with the direction of the arrow shown in the valve body.


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