water ring vacuum pump overload causes

Water ring vacuum pump is a kind of vacuum equipment. Usually, when we use it, we often add oil for lubrication, but in the long-term use process, there will be oil return. Specifically, the oil vapor is affected by the temperature and attached to the original piece, which will not only cause waste of resources, but also cause the heat is not easy to dissipate, and the equipment temperature rises too fast. How to effectively prevent the return of oil to the vacuum pump? EVP water ring vacuum pump manufacturer answers how to effectively prevent the return of oil. First, we need to know clearly the reasons for the return of oil to the vacuum pump. Then, we need to find solutions according to the reasons.

When the vacuum pump is stopped, if there is an oil hole connected with the pump cavity or the exhaust valve, shaft seal, pump cover plane, intake pipe, gas valve and other seals are not tight, due to the existence of the liquid level difference and the gravity effect and the pressure difference between the oil tank and the pump cavity when the pump cavity is in the vacuum state, the oil will return to the pump cavity. When the oil volume is large enough, the oil will return to the air inlet pipe, causing resistance during the next start-up It is difficult to start because of the large force on the rotor and rotor, the large force on the exhaust valve, which affects the service life of the parts and reduces the reliability of the pump.

The return oil of water ring vacuum pump may be caused by the following reasons:

1. The cooling water path is blocked or the water pressure is not enough, which leads to the decrease of cooling capacity, the heating of the upper half of the vacuum pump, and the poor liquefaction of oil and steam.

2. The heating temperature is too high, because the power of vacuum pump heater is not consistent with the rated power, it is too high, resulting in a large amount of steam, thus causing oil return.

3. If the oil filling quantity is too high, the steam circulation will be slow, and it will be detained when it is compressed to the lower level, resulting in oil return.

4. After oil oxidation and vacuum pump oil oxidation, viscosity and steam flow are affected. If the injection speed is not reached, it will naturally return to the vacuum chamber.

5. The operation time of vacuum pump is more than 8-10 years, or it is used in harsh environment.


The above points are the reasons why the water ring vacuum pump returns oil. Therefore, the manufacturer of EVP water ring vacuum pump said that it should try to avoid stopping the pump to return oil. The principle is to cut off the oil circuit when the pump is stopped, eliminate the negative pressure in the pump cavity, reduce the liquid level difference and reduce the amount of oil returned.

1. Connect the water inlet pipe of vacuum pump with 4MPa air source, blow out the scale, and the water outlet pipe also blows out with 4MPa. If there are many scales and they are firm, dilute hydrochloric acid can be introduced. Or replace the vacuum pump.

2. The replacement of electric furnace wire can be solved.

3. According to the information provided by the manufacturer, the control of oil filling quantity can be avoided.

4. Remove the vacuum pump, take out the pump core, clean it with 120 × gasoline, polish it, polish off the carbon deposit and black oxide layer, clean and dry it with 120 × gasoline again, install it, pour in the vacuum pump oil or silicone oil, heat it for several times, and then put it into operation to prevent contamination of the workpiece.

5. Replacement can be considered to improve work efficiency and maintenance costs.

How to effectively prevent oil return? There are several important points as follows:

1. Separate the oil near the exhaust valve from other oil, and the oil level is only slightly higher than the partition wall.

2. Move the oil tank and exhaust valve to the side to reduce the oil level and oil volume.

3. The plane of valve seat shall be flat, and the valve plate shall be elastic.

4. The static sealing part of shaft seal shall be firm and timely replaced.

5. Add a pipe into the oil hole so that the oil level is only slightly higher than the oil inlet.

6. Set check valve mechanism to automatically close the oil inlet when the pump stops.

7. Set oil pump and auxiliary mechanism, and cut off the oil circuit when stopping the pump.

8. The vacuum pump port is equipped with a charging valve.

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