Roots vacuum pump the proper use of methods

Roots vacuum pumps are widely used in paper machine web department, vacuum pressure roller, vacuum pressing, felt dehydration and other paper consumption in the key parts of the process. Roots pump output directly affects the production and quality of paper. When its flow rate decreases, the degree of vacuum decreases, it will cause changes in the moisture of the paper, the formation of consumer sticky roller, embossing and other diseases. Therefore, good Roots pump is very important.

Roots vacuum pump the proper use of methods

First, often adjust the impeller rotor clearance

As we all know, the Roots pump is a kind of pump that is caused by two "8-shaped" relative rotation of the rotor meshing caused by volume changes to produce a vacuum, which is also called a positive displacement pump. There must be a continuous line of contact at the site where the rotor of the pump is to be engaged during operation to prevent backflow of gas from the exhaust port into the vacuum pump. Therefore, in the operation must always check the two rotor meshing situation. With the extension of the use of time, long-term wear impeller, but also limited by the directional rotation, the formation of two impeller meshing gap uneven, and even the onset of the collision, leading to the round table hollow depression. Therefore, the two impeller rotor in the outer diameter, the length of a different level of wear and tear, between the impeller, impeller rotor and the housing gap also increases. Thus reducing the vacuum pump Roots pump, and big and small. It is necessary to timely repair and adjust the clearance of the impeller and the gap between the end cap and the pump housing.

If the impeller rotor clearance is too small, will make the Roots pump tightening ratio increases, causing the air temperature heating pump, and soon lead to the gear box and the motor fever. Two impeller rotor gap becomes smaller due to more additives, fillers, rubber and other objects attached to the impeller appearance. When this phenomenon occurs, the two rotors become too tight and even jammed. After stopping the machine, it is very difficult or not to be rotated at the start-up. There is an attack when the motor burns out. Therefore, it is necessary to constantly clean the pump housing wall and impeller rotor surface. 5% sodium hydroxide solution can also be used for cleaning solution, and 5% hydrochloric acid solution can also be used. After pickling, rinse with clean water to avoid corrosion.

Second, always check the pump shaft seal status

Pump shaft seal is to prevent the compressed gas pump leaks between the pump shaft and the pump housing, but also to avoid the outside air immersed in the pump. Often used mechanical seal and anti-spiral seal, asbestos packing seal and rubber seal. One of the best mechanical seal. Recently, the newly developed Northeastern University magnetic sealing effect is very good.

Third, a reasonable choice Roots pump revolutions

In the application of Roots pump must be adjusted according to practical needs of its rotation. Obviously, the progress of revolutions can increase the theoretical displacement, the volumetric efficiency increases, the output increases obviously, but the resulting increase of noise will worsen the operating environment. Consumption in order to increase the number of revolutions to improve pump talent, should be allowed within the workshop noise adjustment. Usually do not use the method of improving the number of revolutions. As pumping speed is higher than the rated operating value, in addition to bypass valve to stop adjusting, but also reduce the speed, reduce reactive power consumption. This device itself, to reduce defects, reduce vibration, increase power storage, improve overload, while improving the operating environment and reduce noise.

Fourth, Roots vacuum pump in series

In the consumption of the pump will often fail to meet the request and the two pumps used in tandem. Ordinary Roots pump high efficiency workspace is between -300 ~ -400mmHg column, to reach more than -500mmHg column, the vacuum of a single pump is more difficult to accomplish, which can be used in tandem with two pumps. Conforming to this process, the series mode should be put in front of the pump from the pre-pumping effect, pumping speed behind the pump must be greater than the former 1.5 to 2 times the pump. Only in this way can we exert due efficiency.

Foreign Roots pump series not only the use of the same type of ability to different sizes of the two pumps, but also often use two different types of pumps, still make the front suction pump capacity is small, after the suction pump capacity, designed to coaxial drive, so Coaxial compensation, two pump current changes in small, easy to operate.

Use tandem unit should pay attention to white water backflow phenomenon. When tandem pump sets are shut down, there is often a lot of white water from the machine going into the pump chamber, especially the rear suction pump of the unit. Suction port below the pump body, water can not be swept, sometimes higher than the pump rotor water level above 250mm. If consciously start in such a situation, the suction of the working medium from gas into water, the motor must be overloaded trip. Approach is to install a one-way valve on the inlet pipe to prevent white water into the pump, shut down at any time to remove stagnant water.

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