Overview:

The air-cooled Roots vacuum pump is an enhanced version of the ordinary Roots vacuum pump, featuring an additional bypass gas cooling system. The external cooler enables the gas to automatically undergo cyclic cooling of the rotor and the pump body. The cooling gas enters the pump's suction chamber from both sides of the pump body, preventing the pump from overheating due to compression of the gas, allowing it to operate reliably and stably for a long time under high pressure difference and high compression ratio. However, it has no impact on the pumping performance of the pump. The pump can be used alone or in series with multiple units, or it can be connected in series with a liquid ring vacuum pump and an ordinary Roots vacuum pump to form a unit, achieving higher vacuum levels to meet various process requirements.
 

Working principle of the air-cooled Roots vacuum pump:

The structure of the ZJQ series air-cooled Roots pump is shown in the figure. In the pump chamber, there are two rotors (with two or more vanes) installed on a pair of parallel shafts. They rotate synchronously in opposite directions by means of a pair of gears with a transmission ratio of 1. Between the rotors and the inner wall of the pump casing, there is a certain gap, which enables high-speed operation. Compared with the ZJ series ordinary Roots vacuum pumps, the ZJQ series air-cooled Roots vacuum pumps are designed with a return port on the appropriate position of the pump body side. The cooled gas is introduced into the pump chamber to cool the rotors, keeping the rotor temperature within the specified range. Therefore, the ZJQ series air-cooled Roots vacuum pumps can withstand higher pressure differences (up to 90 kPa) without overheating.

Feature:

It can directly discharge into the atmosphere and has no wastewater discharge.
It can be connected in series with the previous stage pump to form a Roots unit, achieving remarkable energy-saving effects. Compared with ordinary Roots pumps, since the ZJQ air-cooled Roots vacuum pump can operate under high pressure differences, it can appropriately reduce the number of the previous stage pumps to achieve energy-saving results.
The application range is wide. Because the exhaust side can withstand high pressure, it effectively solves the overload and overheating problems caused by excessive pressure difference and poor vacuum degree of the preceding pump in ordinary Roots vacuum pumps.
It can operate under higher inlet pressure. The ZJQ series air-cooled Roots vacuum pump can theoretically operate when the inlet pressure is at atmospheric level.
The motor power is not certain. For the ZJQ series air-cooled Roots vacuum pump, the required motor power needs to be determined by calculating the maximum pressure difference during actual operation based on the process conditions.
The ZJQ type Roots pump (air-cooled type) transmits torque. The dynamic seal on the main shaft for torque transmission is a static seal (i.e., frameless oil seal or mechanical seal), achieving zero leakage transmission of power.
The ZJQ type Roots pump (air-cooled type) has no mechanical contact friction and no noise. It can avoid high-frequency vibration and transfer power to achieve smooth operation of the Roots vacuum pump.
The ZJQ type Roots pump (air-cooled type) can provide overload protection during the operation of the working machinery.
Compared with the rigid coupling, the ZJQ type Roots pump (air-cooled type) has no impact during startup, and it is more convenient for installation, disassembly, debugging and maintenance.
The ZJQ type Roots pump (air-cooled type) has changed the shaft dynamic seal to a isolation sleeve static seal. This can completely eliminate the major problems such as vacuum leakage and lubrication oil leakage caused by the wear of the shaft dynamic seal, and achieve long-term sealing.
The ZJQ type Roots pump (air-cooled type) does not require lubrication, and there is no contamination from the medium or lubricants, thus protecting the environment.
The ZJQ type Roots pump (air-cooled type) has a seal performance that is independent of the rotational speed of the shaft.
This series of pumps have the same installation dimensions and performance parameters as the ordinary ZJ and ZJP types.