Reasons for Overheating of Gear Oil Pump Motor and Repair of Worn Pump Cover

The main reason for overheating of gear oil pump motor

The selection of gear pump motor is very important. Improper selection can lead to overheating and even burning of the motor. How to analyze the causes of gear pump motor heating mainly includes several aspects.

1、 If the packing gland is pressed too tightly or the mechanical seal spring is adjusted too tightly: readjust the compression amount of the gland or mechanical seal spring.

2、 Poor pump assembly, friction or motor not concentric with pump shaft: Check the assembly and eliminate assembly faults.

3、 Motor shaft power gear oil pump configuration motor requirements: Select the appropriate motor according to the series spectrum, and if the medium density exceeds the gear oil pump configuration motor: Configure the appropriate motor for the gear oil pump.

It is possible to analyze each of the above conditions one by one, identify the cause of motor overheating, and repair the gear oil pump according to the corresponding fault cause.

What are the main reasons for mechanical seal leakage in gear oil pumps?

The problem of mechanical seal leakage in gear pumps and gear oil pumps has always been a major concern for customers. Due to the wide variety of mechanical seals available in the market, we will now explain one by one the situations of mechanical seal leakage in commonly used gear oil pumps in our daily lives.

The mechanical seals used in conventional KCB gear oil pumps or YCB arc gear pumps are EX series or FOED series. Both the dynamic and static rings of these two types of mechanical seals are made of a combination of graphite to graphite or graphite to silicon carbide without customer requirements. These two types of mechanical seals, due to material limitations (they are not used for conveying lubricating grease, etc.), can only be used when conveying media with lubricating temperatures not exceeding 100 ℃. However, customers often do not understand these specific situations, so some customers choose this type of mechanical seal gear oil pump. If it does not transport lubricating media, it will cause leakage of the mechanical seal. Alternatively, if the customer's conveying medium is corrosive or contains a small amount of solid particles, choosing conventional mechanical seals may cause rapid wear of the mechanical seal's dynamic or static rings, resulting in leakage of the gear oil pump. Or due to the corrosive nature of the conveyed medium, premature damage to the O-ring seal on the mechanical seal may cause leakage of the gear oil pump mechanical seal.

Repair of worn gear end face and pump cover of gear pump

There is some clearance between the gear end face and the inner plane of the pump cover, which is called end face clearance. The wear generated by the contact surface between the gear end face and the inner plane of the pump cover during work will increase the clearance between this end face. When exceeded, it will have a significant impact on the pump oil volume.

When the gear end face wears out, the end face can be ground flat, and at the same time, the separation surface of the gear pump housing can be ground to ensure that the end face clearance of the pump is within the required range.

Secondly, due to the wear of the gear teeth in the direction of tooth thickness, the meshing clearance between the active and passive gears increases. Its wear characteristic is heavy wear on one side, so the gear can be flipped 180 degrees for use.

1、 Unscrew the water inlet plug of the gear pump body and inject water (or slurry).

2、 Close the gate valve, inlet and outlet pressure gauges, and vacuum gauge of the water outlet pipeline.

3、 Check for any looseness in the gear pump pipeline and joints. Rotate the gear pump by hand to see if it is flexible.

4、 Add bearing lubricating oil into the bearing body, and observe that the oil level is at the centerline of the oil gauge. Lubricating oil should be replaced or replenished in a timely manner.

5、 The specific principle is as follows: a stainless steel gear pump is equipped with a pair of rotating gears in the pump body, one active and one passive. By relying on the mutual meshing of the two gears, the entire working chamber inside the pump is divided into two separate parts. A is the suction chamber, and B is the discharge chamber. When the gear pump is running, the active gear drives the passive gear to rotate. When the gear disengages from meshing, a local vacuum is formed on the suction side (A), and the liquid is sucked in. The liquid sucked in fills the various tooth valleys of the gear and is carried to the discharge side (B). When the gear enters meshing, the liquid is squeezed out, forming high-pressure liquid that is discharged through the pump inlet and discharged outside the pump. As a result, the pressure difference between the inlet and outlet chambers of the gear pump is reduced, leading to a decrease in the scraping and pressure of the gear teeth, resulting in a decrease in the supply pressure and a decrease in the pump oil volume. The wear of the pump casing's inner cavity is generally repaired using the inner cavity embedding method.

What are the internal characteristics of the structure of a gear pump?

1、 The lubrication of all parts inside the pump is automatically achieved through the use of the output medium during pump operation.

2、 Gear pumps have self-priming properties, so there is no need to inject liquid before each pump start.

3、 However, please note that this protective valve cannot be used for long-term operation as a pressure reducing valve. If necessary, it can be installed separately on the pipeline.

4、 The pump is equipped with a protective valve as overload protection, and the full reflux pressure of the protective valve is 1.5 times the rated discharge pressure of the pump. It can also be adjusted according to actual needs within the allowable discharge pressure range.

5、 The gear has good hardness and strength after heat treatment, and is installed together with the shaft in a replaceable shaft sleeve for operation.

6、 The lubrication of the gear pump is automatically achieved by the conveyed liquid, so there is no need to add lubricating oil during daily operation

7、 Gear pumps are mainly composed of gears, shafts, pump bodies, protective valves, and shaft end seals.

8、 There are correct oil discharge and return grooves inside the pump, which reduces the torque force borne by the gears during operation, resulting in low bearing load, minimal wear, and good pump speed.