Two types of transmission structure arrangements and start-up inspection work for Roots pumps

[1] The two transmission structures of the Roots oil pump are arranged through a pair of gears to achieve relative synchronous operation of the two rotors of the Roots oil pump. The driving shaft is connected to the motor through a coupling. There are mainly two types of transmission structure layout:

One is that the electric motor and gear are placed on the same side of the rotor. The driven rotor is directly driven by the motor end gear, so that the torsional deformation of the active rotor shaft is small, and the gap between the two rotors will not change due to the large torsional deformation of the active shaft, so that the gap between the rotors is uniform during operation

The major disadvantage of this transmission method is that: a. there are three bearings on the driving shaft, which increases the difficulty of processing and assembling the pump, and the disassembly and adjustment of the gears are also inconvenient; b. The overall structure is uneven, and the center of gravity of the pump leans towards the side of the motor and gearbox

Another method is to install the electric motor and transmission gear on both sides of the rotor. This form makes the overall structure of the pump uniform, but the main shaft undergoes significant torsional deformation. To ensure even clearance of the rotor during operation, it is required that the shaft has sufficient stiffness and the connection between the shaft and rotor should be tightened (currently, there are structures where the rotor is welded or cast into one with the shaft). This structure is very convenient for disassembly and assembly, so it is widely used

[2] Startup Inspection of Roots Pump

Before starting the work officially, a series of inspections must be carried out before starting the operation.

. This behavior is mainly aimed at ensuring that the device does not have any malfunction issues before startup, so as to ensure the smooth progress of the subsequent startup operation. It can also avoid accidents that may occur during the startup process of the equipment and cause danger. So what kind of inspection work needs to be done before starting up? Let's take a look together

1. Check whether the liquid level in the water tank of the water flushing pump (front stage pump) reaches more than 3/4 of the water tank. If it is insufficient, make up for it

2. Check if the water used in the water tank is clean, and do not use sewage containing sediment to avoid blockages in the pipeline. The Roots pump will increase the wear of the pump impeller and increase the motor load, causing malfunctions and affecting the service life of the water flushing pump

3. Check the height of the lubricating oil level in the middle pump and main pump body, which must reach more than 3/4 of the oil window. The middle ring vacuum equipment should also check the color of the lubricating oil. If there are many milky white or black impurities in the Roots pump, notify the machine repair to replace the lubricating oil

4. Check if the circulating cooling water circuit of the intermediate pump and main pump is intact, open the inlet and outlet valves of the circulating cooling water, and check if the circulating cooling water inlet and outlet are normal

5. Check if the drain valve of the buffer tank at the bottom of the intermediate pump is closed

6. Check if the circuit is intact and if all indications in the control cabinet are normal

7. Check if the starting pressure of the intermediate pump and main pump on the electrode contact pressure gauge is normal (the starting inlet pressure of the intermediate pump is above 0.065Mpa, and the starting inlet pressure of the main pump is above 0.085Mpa)

Therefore, before starting the Roots pump, it is necessary to perform the above checks and confirm that there are no problems before starting the equipment. But this does not mean that the equipment will not have problems during operation, so it is still necessary for the operator to periodically check the operation of the equipment to ensure that it is in good condition, in order to avoid sudden unexpected situations during operation that may not be dealt with in a timely manner and cause significant danger