Common faults of gear oil pumps and maintenance methods of gear oil pumps

               
Update: 18-06-2021
               
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Gear oil pump manufacturers understand that the flow ad […]

Gear oil pump manufacturers understand that the flow adjustment methods of arc gear pumps mainly include regulating valve control, variable speed control, and pump parallel and series adjustment. Due to the different principles of various adjustment methods, in addition to their own advantages and disadvantages, the energy loss caused is also different. In order to find a better, less energy-consuming, and more energy-saving flow adjustment method, it is necessary to fully understand the arc gear pump. The relationship between flow regulation methods and energy consumption. In fact, the essence of the flow adjustment of the arc gear pump is to change the working point of the arc gear pump. The working point of the arc gear pump is determined by the characteristic curve of the pump and the characteristic curve of the piping system. Therefore, changing any one of the characteristic curves can achieve the purpose of flow adjustment. The simple way to change the flow of the arc gear pump is to use the pump The opening degree of the outlet valve is controlled, and its essence is to change the position of the pipeline characteristic curve to change the working point of the pump. Or change the characteristic curve of the arc gear pump. Although these two methods can change the characteristic curve of the arc gear pump to achieve the purpose of adjusting the flow rate and changing the pressure head at the same time. But for the pump that is already working, the method of changing the pump structure is not convenient, and because the structure of the pump is changed, the versatility of the pump is reduced. Although it is economical and convenient to adjust the flow rate at certain times, it is rarely used in production.

Common faults of gear oil pumps and maintenance methods of gear oil pumps

(1) Trouble phenomenon: the pump consumes too much power

Reasons: 1. The speed is too high; 2. The viscosity of the liquid is too high; 3. The outlet pressure is higher than the calculated value, check the pressure gauge; 4. The stuffing box gland is too tight; 5. The pump is not centered; 6. The extra clearance is not enough;

Treatment method: 1. Check whether the motor speed, reducer speed ratio and pulley size are correct; 2. Heat the liquid, increase the pipe size, reduce the speed, or use a larger power motor; 3. Increase the outlet pipe size or reduce the length , Reduce the speed, or use a larger power motor; 4. loosen the packing gland; 5. re-align; 6. check whether the parts have resistance or signs of contact, and increase the gap if necessary;

(2) Failure phenomenon: the reading of the vacuum gauge at the inlet end is too large

Reasons: 1. The inlet pipeline is blocked, the bottom valve is stuck, the gate valve is closed, and the filter is blocked; 2. The viscosity of the liquid is too high; 3. The self-priming height is too high; 4. The pipe diameter is too small;

Treatment methods: 1. Dredge the bottom valve, open the gate valve, dredge the filter, and check and eliminate the cause of the blockage; 2. Heat the liquid and increase the pipe size; 3. Increase the liquid level of the feed tank; 4. Increase the pipe diameter;

(3) Failure phenomenon: the pump does not reach the rated flow

Reasons: 1. Insufficient material supply or cavitation phenomenon; 2. Partial blockage of the filter; 3. Air leakage in the suction pipe; 4. The motor does not reach the rated speed; 5. The pressure relief valve is set too low or opened; 6. The pump is worn out; 7. The end face gap is too large; 8. The position of the pump head is incorrect;

Treatment method: 1. Increase the size of the inlet pipe or reduce the length; 2. Drain the filter; 3. Seal the leaking part tightly; 4. Increase the motor speed; 5. Increase the set pressure of the pressure relief valve, under normal circumstances The pressure relief valve will not open; 6. Replace the worn parts; 7. Reduce the end face clearance; 8. Adjust the position of the pump head to the correct position;

Gear pump is a kind of general fluid machinery widely used in chemical industry systems. Generally, the flow and pressure head of the selected arc gear pump may be inconsistent with the requirements in the pipeline, or due to changes in production tasks and process requirements, it is required to adjust the flow of the pump at this time. The common gears of gear pumps include straight teeth, helical teeth, herringbone teeth, and helical teeth. The tooth profiles mainly include involute and circular arc types. Usually small gear pumps use involute spur gears, high-temperature gear pumps often use displacement gears, and involute helical gears are used for melt pumps that transport high-viscosity and high-pressure polymer melts. The gear and the shaft are made into one body, and its rigidity and reliability are higher than that of a gear pump made of a single gear and shaft. The gears of foreign low-pressure gear pumps often adopt a square structure, that is, the tooth width of the gear is equal to the diameter of the addendum circle. The tooth width of high-viscosity gear pumps used in high-pressure applications is smaller than the diameter of the addendum circle. This is to reduce the radial pressure area of ​​the gears and reduce the load of the gears and bearings.

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