I. Operating Principle
- In the pump body of Roots vacuum pump, two three-blade rotors are installed in parallel in the pump body, and the two three-blade rotors operate in opposite directions. Through the rotation of the two three-blade rotors, the medium gas is sucked in, compressed and transported to the inlet of the next stage vacuum pump.
- The two three-blade rotors do not contact each other or the pump body. Therefore, there is no need to add any lubricating fluid or working fluid in the pump cavity, which can also be called dry roots vacuum pump.
- Figures I to IV below show the process of two three-blade rotors rotating in the pump cavity and completing primary suction and exhaust
II. Main Features
- The rotors are all three-blade rotors. Compared with the traditional two-blade rotors, the extraction efficiency is higher, the temperature rise is lower, the noise is low, the vibration is small, and the stability is better.
- The end cover adopts hollow air cooling design, the oil tank cover adopts water cooling design, and the pump operating temperature is lower.
- Both ends of Roots pump are lubricated by oil. The bearing lubrication is reliable and the service life is longer.
- Roots pump seal adopts shaft end mechanical seal plus internal composite seal, and the seal structure is safe and reliable.
- Roots pump is generally used as booster pump and is not recommended to be used alone.
III. Parameters
| Model | JZJ-70 | JZJ-150 | JZJ-300 | JZJ-600 | JZJ-1200 | JZJ-2500 | |
| Speed ( M3/H, 50HZ ) | 250 | 540 | 1080 | 2160 | 4320 | 9000 | |
| Speed ( L/S , 50HZ) | 70 | 150 | 300 | 600 | 1200 | 2500 | |
| Vacuum(Pa) | 5×10－2 | 5×10－2 | 5×10－2 | 5×10－2 | 5×10－2 | 5×10－2 | |
| Maximum allowable differential pressure (Pa) | 12000 | 10000 | 8000 | 6000 | 5000 | 4000 | |
| motor speed（r/min） | 2900 | 2900 | 2900 | 2900 | 2900 | 2900 | |
| inlet(mm) | 80 | 100 | 160 | 200 | 250 | 320 | |
| outlet(mm) | 50 | 80 | 100 | 160 | 200 | 250 | |
| weight(KG) | 87 | 198 | 290 | 490 | 790 | 1550 | |
| power(kW) | 1.5（2.2） | 3 | 4 | 5.5(7.5) | 11 | 18.5 | |
| recommended pre-stage oil pump | 2X-15 | 2X-30 | 2X-70 | 2X-70×2 | JZJ-300+2X-70 | JZJ-600+2X-70*2 | |
| recommended pre-stage screw pump | JSP-180 | JSP-280 | JSP-540 | JSP-540 | JZJ-300+JSP-540 | JZJ-600+2X-70*2 | |
IV. Pumping Curve(work with screw vacuum pump)
