Created on:2022-03-14 13:05

Repair of speed regulating valve

Repair of speed regulating valve

1. Repair of valve core

There are two valve cores of speed regulating valve, namely throttle valve core and constant pressure differential pressure reducing valve core.

When the valve core is not seriously strained and worn, the clearance between the valve core and the valve hole can still be used after polishing. However, in case of serious wear and tear, 0.05 ~ 0.08mm shall be removed by centerless grinding, and then the outer circle shall be plated before grinding or brush plating. For brushless plating equipment, a new valve core can be reprocessed.

The fitting clearance between throttle valve core and valve hole shall be within the range of 0.007 ~ 0.015mm, and the fitting surface finish of valve core shall not be lower than the technical requirements. The fit clearance between the large end of the pressure reducing valve core and the valve hole shall be 0.015 ~ 0.025mm, and the fit clearance between the small end and the valve sleeve shall be 0.007 ~ 0.015mm.

2. Repair of valve sleeve

When the valve is used for a period of time, the accuracy of the valve sleeve will be lost due to the wear in the hole of the valve sleeve after cold pressing. It needs to be repaired. Generally, the valve sleeve hole is not pressed out from the valve body during repair, so as to avoid damaging the cylindrical interference fit after pressing out. If the pressure reducing valve core is replaced or repaired, generally only grind the valve sleeve hole.

3. Repair of valve body

The repair of the valve body is mainly the valve hole. After a long time of use, the valve hole is generally out of round due to wear, taper and strain. Generally, the valve hole can be grinded and repaired. Qualified users can repair the valve hole with diamond reamer, and the valve core can be reconfigured according to the size of the repaired valve hole.

4. Repair of hot pressing and cold pressing of valve sleeve

The interference between the valve sleeve and the valve body hole shall be kept at 0.002 ~ 0.010mm, so it is necessary to press hot or cold during assembly without knocking, so as not to damage the accuracy of the hole.

During hot pressing, generally put the valve body in hot oil at about 150 ℃, soak it for 5 ~ 10min, then put the valve sleeve into the valve hole, take it out and cool it.

When cooling, a bottle of carbon dioxide fire extinguisher for fire fighting can be used to blow at the valve sleeve, and it can shrink to fit into the valve hole in 2 ~ 3min. Attention shall be paid during operation. Be careful when blowing with carbon dioxide fire extinguisher. It shall not be blown on people. The operator shall wear gloves to prevent frostbite. Before assembly, dirt shall be removed from the inner hole and top cover, and the surface shall be coated with engine oil.

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