Structural characteristics and causes of petrochemical stainless steel gear pumps

[1] 1. Structural characteristics of stainless steel gear pump

Structure of stainless steel gear pump

1. Gear oil pump is a horizontal rotary pump, mainly composed of pump body, gears, bearing seats, bearings, and sealing devices

2. The pump body and bearing seat are made of gray cast iron, and the gears are made of carbon steel. Copper or stainless steel materials can also be used according to user needs. 3. There is a packing box on the bearing seat, which serves as an axial seal. KCB-300-960 pumps use mechanical sealing devices and single row radial ball bearings. KCB-18.3-83.3 pumps are composed of three oil resistant rubber rings and a retaining ring with an intermediate lining. The sealing degree is adjusted by adjusting the two nuts on the compression cover. The bearings are made of copper based powder oil bearings. In addition, stainless steel gear pumps can all use packing seals to use flexible graphite with good elasticity, low temperature resistance, stable chemical properties, and self-lubricating performance as the packing

4. The stainless steel gear pump is equipped with a valve. When the pump or discharge pipeline malfunctions or the discharge valve is accidentally closed, causing high pressure and high pressure impact, the valve will automatically open, removing some or all of the high-pressure liquid and returning to the low-pressure chamber, thereby providing protection for the pump and pipeline

5. Connect the drive motor directly with an elastic coupling and install it on a common cast iron chassis

Characteristics of stainless steel gear pump

1. The structure of stainless steel gear pump is simple and compact, making it easy to use and maintain.

2. Stainless steel gear pumps have good self suction performance, so it is not necessary to fill liquid before starting the pump each time

3. The lubrication of stainless steel gear pumps is achieved automatically by conveying liquid, so there is no need to add additional lubricant during daily work

4. Using elastic couplings to transmit power can compensate for minor deviations caused during installation. When subjected to inevitable hydraulic impact during pump operation, it can provide good buffering effect

[II] Reasons for the inability to increase pressure during the use of gear pumps

All stainless steel gear pumps should be disassembled separately to check which part of the pump is causing the jamming due to friction.

. Timely clean the foreign objects inside the pump and the burrs on the surface of each spare part caused by wear. After cleaning, the main reasons for jamming are analyzed as follows: firstly, due to the small transfer clearance and wear caused by thermal expansion during operation, the jamming occurs. The solution is to replace the graphite or PTFE gaskets of the pump body and the front and rear end covers with slightly thicker gaskets than the original ones; The second point is that when encountering a situation where the stainless steel gear pump shaft sleeve is locked with the shaft, the main reason is that the clearance between the sleeve and the shaft is too small, or the hardness of the sleeve material does not match the hardness of the shaft. It is necessary to change the communication material or increase the clearance between the sleeve and the shaft

After using the gear pump for a period of time, there is often a phenomenon of pressure not rising or insufficient pressure. Mainly due to the excessive internal clearance caused by the wear of internal components in the gear pump, the internal leakage of the gear pump increases during operation, and the vacuum degree decreases. The main reasons for these phenomena are several aspects:

The gear end face of the gear pump is severely worn. Solution: Replace the gear

The thrust plates on both sides of the gear pump gear are severely worn. Solution: Replace the thrust plate

The outer circle of the gear pump gear is severely worn. Solution: Replace the gear

The stainless steel gear oil pump shaft sleeve is severely worn. Solution: Replace the shaft sleeve