The continuous vacuum coating process is used to coat copper, aluminum and other metal strips with absorption coating. The solar energy collector material has a solar energy absorption rate of up to 95%. In order to ensure high-quality products, the dry screw vacuum pump used in the manufacturing process required by the previous vacuum. There are many problems in the original oil lubricated rotary vane vacuum pump of the coating machine. The process gas inhaled corrodes the pump oil in the vacuum pump, which often leads to failure and high maintenance costs. The most fundamental requirement is to ensure that the initial vacuum is highly reliable and the required vacuum degree can be maintained to avoid production shutdown, and the use of dry screw vacuum technology can maximize the above problems.
1. Test to ensure the best adaptability of vacuum solution
Before the first commissioning, the dry screw vacuum pump has been thoroughly tested, and the detailed requirements of the test process are clearly specified. With a water-cooled motor, the vacuum pump operates smoothly and does not release any heat to the surrounding area. The whole test process is very valuable: the vacuum system that has been put into operation now can highly guarantee the operation safety and maintain the reliable supply of vacuum.
2. Realize multi-stage depressurization of process section
The whole coating process is completed continuously in different pressure sections. When the coated coil is loaded into the first stage coating chamber for locking, the dry screw vacuum pump only generates vacuum relative to atmospheric pressure. In this stage, two dry screw vacuum pumps are used, each with a suction rate of 630 m3 / h and a final pressure of 0.05 MABR. In the second stage of vacuum process, another vacuum pump of the same specification is added. In the third and fourth stage vacuum process sections, a combination of the fourth dry screw vacuum pump and one roots vacuum pump is equipped to further improve the vacuum degree.
3. Reliable front vacuum system to ensure safe operation
Because of the dry screw technology, there is now a suitable solution to maintain the previous stage vacuum. The principle of oil-free compression means that there is no possibility of contact between the vacuum pump oil and the extracted medium. The internal temperature of the vacuum pump will not cause gas condensation. This means that there is no deposit in the vacuum pump. The use of dry screw vacuum pump instead of oil lubricated vacuum pump increases the operation reliability of the machine.
A variety of EVP products may be used to generate the medium and high vacuum levels required for plasma coating. Several variants of the range of screw vacuum pumps have proved to be particularly suitable, also in combination with a vacuum-boosters. For smaller plasma coating plant with loadlock systems scroll vacuum pumps may be used, with combinations of rotary vane vacuum pump and molecular vacuum pumps for the process chamber.