Influence of inlet layout on suction path of gear oil pump

The layout of the intake pipeline has a great impact on the suction path of the gear oil pump, which is mainly divided into the following points:

1. When installing the oil inlet pipeline of the gear oil pump, the degree of the section or the upward warping

This will make the intake pipe collect air, reduce the vacuum of tubing and centrifugal pump, so that the suction head of the centrifugal pump decreases, and the amount of oil is reduced.

Accurate approach is: the degree segment should be slightly tilted to the direction of the oil source, should not be degree, not to tilt up.

2. Large diameter gear oil pump with small tubing for oil delivery

Many users think that this can improve the actual head of the gear pump, the actual head of the self-priming centrifugal pump = total head ~ lost head.

When the oil pump model is determined, the total head is certain;

The loss of head is important from the pipeline resistance. The smaller the pipe diameter is, the greater the resistance is, and the greater the loss of head is. Therefore, after reducing the pipe diameter, the actual head of the centrifugal pump can not be increased, but will decline, leading to the drop in the efficiency of the gear pump.

Similarly, when a small diameter oil pump is pumped with a large pipe, the actual head of the oil pump will not be decreased, but the loss of head will be reduced due to the reduction of the resistance of the pipeline, so that the actual head will be improved.

Some operators think that when a small diameter oil pump is pumped with a large pipe, it will greatly increase the motor load. They think that after the pipe diameter increases, the pressure of the oil in the pipe outlet on the pump impeller is large, so it will greatly increase the motor load.

As everyone knows, the size of the liquid pressure is only related to the height of the head, and has nothing to do with the size of the pipe cross-sectional area.

As long as the head is certain, the size of the impeller of the gear oil pump is the same, no matter how big the diameter of the pipe is, the pressure acting on the impeller is certain.

However, when the pipe diameter increases, the oil flow resistance will decrease, and the flow rate will increase, and the power consumption will also increase appropriately.

However, as long as it is within the rated head range, the oil pump can work normally no matter how the pipe diameter is increased, and it can also reduce the loss of the pipeline and improve the efficiency of the oil pump.

3, gear oil pump into the pipeline with more elbow

If more elbows are used on the oil inlet line, local oil flow resistance will be increased.

And the elbow should be turned in the vertical direction, do not allow to turn in the degree direction, so as not to collect air.

4. The inlet of the gear oil pump is directly connected with the elbow

This will make the oil flow through the elbow into the impeller uneven distribution.

When the diameter of the inlet pipe is larger than the inlet of the oil pump, the eccentric reducer pipe should be installed.

The flat part of the eccentric reducer should be mounted on top and the beveled part on the bottom.

Otherwise collect air, reduce the amount of oil or pump oil, and there is a crash, etc.

If the diameter of the oil inlet and the oil inlet of the oil pump are equal, a straight pipe should be added between the oil inlet of the oil pump and the elbow, and the length of the straight pipe should not be less than 2 ~ 3 times the diameter of the oil pipe.

5, the gear oil pump with the bottom valve of the inlet pipe is not vertical

If installed in this way, the valve cannot close itself, resulting in oil leakage.

Accurate installation method is: with the bottom valve of the inlet pipe, the next section is best vertical.

If vertical installation is not possible due to topographic conditions, the Angle between the tubing axis and the degree surface should be above 60°.

6. The inlet position of the gear oil pump inlet pipe is wrong

(1) The interval between the oil inlet of the gear oil pump inlet pipe and the bottom and wall of the oil inlet pool is less than the diameter of the oil inlet.

If there is sediment and other dirt at the bottom of the pool, the interval between the oil inlet and the bottom of the pool is less than 1.5 times of the diameter, it will cause the oil inlet to be not smooth when pumping or suck in sediment debris, and block the oil inlet.

(2) when the oil inlet depth of the oil inlet of the oil inlet of the oil inlet pipe is not enough, it will cause the oil surface around the oil inlet pipe to produce a vortex, affecting the oil inlet and reducing the oil output.

Accurate installation method is: small and medium-sized oil pump inlet depth should not be less than 300 ~ 600mm, large oil pump should not be less than 600 ~ 1000mm

7. The outlet of the sewage pump pipe is above the normal oil level of the oil outlet pool

If the oil outlet of the sewage pump is above the normal oil level of the oil pool, the pump head will be increased, but the flow will be reduced.

If the oil outlet must be higher than the oil level of the oil outlet pool due to the limitation of topographic conditions, an elbow and a short pipe should be installed at the pipe outlet to make the pipe siphon and reduce the height of the oil outlet.

8. High head self-priming sewage pump works at low head

Many customers usually think that the lower the head of the centrifugal pump, the smaller the motor load. Under the misdirection of this wrong understanding, when buying the oil pump, the head of the oil pump is often selected very high.

In fact, for the sewage pump, when the sewage pump model is determined, the size of the power consumption is proportional to the actual flow of the sewage pump.

And the discharge of sewage pump will decrease with the increase of head, so the higher the head, the smaller the flow, the smaller the power consumption.

On the contrary, the lower the head, the greater the flow, the greater the power consumption.

Therefore, in order to prevent motor overload, it is generally required that the actual pumping head of the oil pump should not be less than 60% of the calibrated head.

Therefore, when high head is used for pumping oil with too low head, the motor is easy to overload and heat, and the motor can be burned down seriously.

If it is used in emergency, a gate valve must be installed on the oil outlet pipe to adjust the amount of oil (or block the small oil outlet with wood and other things), so as to reduce the flow and prevent motor overload.

Pay attention to the temperature rise of the motor. If the motor is overheated, turn down the flow of the oil outlet or shut it down in time.

This is also easy to misunderstand, some mobile operators think that blocking the oil outlet, forced to reduce the flow, will increase the motor load.

In fact, on the contrary, the outlet pipe of the regular high-power centrifugal pump drainage and irrigation unit is equipped with gate valves. In order to reduce the motor load when the unit starts, the gate valve should be closed first, and then gradually open the gate valve after the motor starts. This is the reason.