Roots Vacuum Pump in Paper Industry

Roots Vacuum Pump advantages:

(1) To reduce power consumption, in general, Roots pump consumes only 40-50% of the power consumed by other equipment. This saving effect can be achieved because of the use of Roots vacuum pump with air-water separation device and the use of self-priming centrifugal pump.

Contrast example: For a container with capacity of 52 m3/min, vacuum degree needs to be pumped to 4x104Pa (absolute pressure is 6x104Pa). Power comparison on the pump shaft: liquid ring pump is 95 horsepower, tolerance of capacity and power is <10%. For single-stage Roots pump, 55 horsepower, capacity and power tolerance is (+5%).

(2) The capacity of the flexible pump can be adjusted to the required value by the adjusting device, and there is a minimum specific power value. Roots vacuum pump belongs to the variable capacity type, which can stipulate a 25% reserve belt. If the required conveying capacity is not considered carefully (more or less) during manufacture, the correct way to deal with it is to change the diameter of the pulley. The ideal operation effect can be obtained by rotating speed.

Roots vacuum pump belongs to variable displacement pump, so: 1) capacity is proportional to speed, 2) power is proportional to speed and pressure.

In all cases, Roots Vacuum Pump can reduce the speed by 50%, and also can ensure the above advantages.

(3) Improving the vacuum degree of working quality can be obtained by a certain method, but it has nothing to do with the amount of water pumped by the pump. During the production of parchment paper, a liquid ring pump was installed on the vacuum roller and attention was paid to the variations of vacuum degree. Its absolute pressure was 40-45 mmHg. A separator and a Roots pump are installed on the vacuum volt roll. With the same recording instrument, the absolute pressure is measured to be 5 mmHg.

(4) Once the self-protection paper machine is in operation, it should not stop working. In practice, a self-protection system is adopted, that is, two pumps with identical specifications are used to form a two-stage pump group, and only one motor is used to drive it. In case one machine stops working, the other can work continuously. But the pipeline should be laid well. At this point, the linear velocity and vacuum may temporarily decrease slightly.

(5) Four common basic methods are as follows:
1.vacuum pump with separator;
2. separation device is placed in the network and wool part;
3. in order to ensure the vacuum degree of each paper machine, a central vacuum unit can be set up;
4. separation device can solve the problems of high vacuum degree and low vacuum degree.

(6) Vacuum unit can be installed in any suitable position. Since Roots vacuum pump only sucks air, it can be placed randomly within 100m from the vacuum point. The only thing to be noticed is that the pressure difference (which is very small) is generated when air passes through the pipeline. It is preferable to avoid the low pressure zone in the tube.

Separate gas and water separators (columnar landing separators, separator boxes, etc.) are installed as closed systems with vacuum points.

(7) Water immersion pump is harmless Roots vacuum pump can withstand accidental water immersion. It can pump water out.

(8) The reduction of maintenance workload is due to:

1.gas-water separation avoids machine damage due to corrosion and wear;

2. Roots vacuum pump structure determines (due to non-contact between parts).

(9) Little or no water is consumed. Roots pumps reduce water consumption. A liquid ring pump with a general capacity of 52 m3/min requires at least 10,000 L/h of pure calcium-free cold water to obtain a vacuum of 300 mmHg, while a Roots vacuum pump can operate without water or a small amount of water.

In order to obtain a higher vacuum, it is recommended that the combination of two or three pumps (i.e. two or three pumps in series) be used, and a small amount of water infiltration (about 400L/h) be used.

The purpose of water infiltration:
1.disperse the heat generated by compressed air,
2. improve the volume efficiency of the pump,
3.obtain the minimum power.