The main advantages of using roots vacuum pump device and how to select relevant equipment? Let’s have a brief understanding.
(1) Reduce power consumption: in general, the power consumed by roots vacuum pump is only 40% – 50% of the power consumed by other equipment. This kind of saving effect can be obtained because of the use of Roots vacuum pump with air-water separation device and the use of self-priming centrifugal pump.
Comparison example: for a vessel with a capacity of 52m3 / min and a vacuum degree of 4x104pa (absolute pressure of 6x104pa), the power comparison on the pump shaft: the liquid ring pump is 95 HP, and the tolerance of capacity and power is ± 10%. If a single-stage roots vacuum pump is used, it is 55 horsepower, with a capacity and power tolerance of ± 5%.
(2) Flexible operation: the capacity of the vacuum pump can be adjusted to the required value by the regulating device, and there is a minimum specific power value. The roots vacuum pump belongs to the variable capacity type, which can be specified with 25% reserve. If the required conveying capacity is not considered properly (more or less) during manufacturing, the correct treatment method is to change the diameter of the pulley and change the speed, then the ideal operation effect can be obtained.
Roots vacuum pump is a variable volume pump, so: ① the capacity is proportional to the speed, ② the required power is proportional to the speed and the generated pressure.
In all cases, roots vacuum pump can reduce the speed by 50%, and also can ensure the above advantages.
(3) Improvement of work quality: the vacuum degree can be obtained by a certain method, but it has nothing to do with the amount of water pumped by the pump. In the production of parchment paper plate, a liquid ring vacuum pump was installed on the vacuum couch and various vacuum degree changes were noticed, with the absolute pressure of 40-45mmhg. A separator and a Roots vacuum pump are installed on the vacuum couch, and the absolute pressure is 5mmhg with the same recording instrument.
(4) Self protection: once the paper machine is running, generally do not stop working. In practical work, a self-protection system is adopted, that is, two interchangeable vacuum pumps with identical specifications are used to form a two-stage vacuum pump group, which is driven by only one motor. In case one stops working, the other can work continuously. But the pipes should be laid well. At this time, the linear speed and vacuum may be slightly reduced temporarily.
(5) Four common basic methods are as follows: ① vacuum pump with separator; ② separation device is placed in the mesh part and wool part; ③ in order to ensure the vacuum degree of each paper machine, a central vacuum unit can be established; ④ separation device can solve the problems of high vacuum degree and low vacuum degree.
(6) The vacuum unit can be installed at any suitable position. Since the roots vacuum pump only draws air, it can be placed within 100m from the vacuum point at will. The only thing to be noticed is that the pressure difference (which is very small) is generated when the air passes through the pipeline. It is preferable to avoid the low pressure area in the pipe. The separate gas and water separators (column type falling separator, separator box, etc.) are all installed in a closed system with the vacuum point.
(7) Water immersion pump is harmless roots vacuum pump is able to withstand accidental water immersion. It can pump water out.
(8) There is no need to reduce the maintenance work, because: ① the separation of air and water prevents the machine from being damaged due to corrosion and wear; ② it is determined by the structure of Roots vacuum pump (because parts do not contact each other).
(9) Little or no water is needed. Roots vacuum pump can reduce water consumption. The liquid ring vacuum pump with a general capacity of 52m3 / min needs at least 10000l / h pure calcium free cold water in order to obtain a vacuum of 300MMHG, while roots vacuum pump can operate without water or a little water.
In order to obtain a higher vacuum degree, it is recommended to use two or three-stage pump combination (i.e. two or three pumps in series), and use a small amount of water to penetrate (about 400L / h).
The purpose of infiltrating water is: ① heat member produced by compressed air in ryushan; ② improving the volumetric efficiency of vacuum pump; ③ obtaining the minimum power.