A question about gear pumps
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If there is a centrifugal pump (front) and a gear pump (rear) on a pipeline, and the centrifugal pump is on and the gear pump is off, can the liquid pass through the gear pump and reach the other end of the gear pump (the liquid is xylene)? I am a little confused. Please tell me.
Gear pumps have differential pressure. If the inlet is under pressure, even if the gear pump is not started, the medium will push the gear pump to rotate and be discharged at the outlet, but the pressure at the outlet should be lower than the inlet pressure.
Agree with the second floor's opinion. A pressure difference is formed at both ends of the gear pump, and the gear will rotate.
I think it cannot be done through a gear pump. A gear pump achieves the purpose of transporting media by causing volume changes due to meshing between teeth. Under normal operation, when viewed from the inlet, the teeth increase in volume from meshing to separation, thereby forming a negative pressure to suck in the medium. At the outlet, from separation to meshing, the volume between the teeth becomes smaller and the medium is discharged. If there is no prime mover to provide power and only the inlet is opened, how will the gear rotate if it is to work?
I think it's like the pipe is clogged and the outlet pressure of the centrifugal pump becomes high.
Oh my god, who should I listen to?
Why is it configured this way? Agree with the 4th floor's point of view. However, if there is a power to make the gear pump rotate (such as a disc pump), I think the medium should still be able to reach the other end through the pump, but there will definitely be a pressure drop. Of course, whether it can actually be realized depends on the specific situation, that is, whether the pressure energy of the centrifugal pump is greater than the mechanical energy that allows the gear pump to continue rotating.
Personally I don’t think it can rotate, but there may be very little liquid passing through the gear pump, right? It seems that the seal of the gear pump is not very tight... And the problem is that the viscosity of xylene is very small. Even if the gear pump has power, can it discharge material when it is turned on? As far as I know, gear pumps require materials to have a certain viscosity before they can transport materials... Personal opinion, please point out if there are any mistakes...
I also agree with fallautumn, it should cause the centrifugal pump to hold pressure!
Personally, I think the key to whether a gear pump in such an environment can rotate is to see whether there is reverse self-locking in the power chain of the gear pump. Normally, this is not possible. Because the gear pump has a high working speed, it is usually directly connected to the motor or a V-belt pulley. When the centrifugal pump starts but the gear pump motor does not start, the gear pump essentially becomes a gear motor. The medium flows to the rear through the gear pump.
I once used 0.5MPa compressed air to blow through the pipeline to empty it. As a result, the gear pump spun and the liquid in the front section of the gear pump was drained. In the same way, the centrifugal pump can also drive the gear pump to rotate as long as the pressure is sufficient.
It can definitely pass through the gear pump. There is nothing doubtful about this, because the gear flowmeter is two gears meshing together. Doesn’t the traffic still flow through? The disadvantage of this is that the gear pump is reversed and the motor becomes a generator, which has a certain impact on the motor. In addition, some nuts will loosen, which is the same disadvantage as the centrifugal pump being reversed.
The end clearance of the gear pump can also pass liquids with low viscosity.
Agree with the 2nd floor:victory: :victory: :victory:
Personally, I think that gear pumps that can transport materials rely on pressure differences to transport materials. As long as there is a positive pressure difference between the pump inlet and outlet, the gear pump can only rotate forward and there is no reverse rotation. Similarly, if the outlet pressure difference is greater than the inlet pressure difference, material can also flow from the outlet into the inlet.
Why not get a secondary line from the gear pump inlet and outlet? not understand?
If the outlet pressure of the centrifugal pump is large enough, the gear pump can rotate no matter what medium is transported, especially if the external gear pump is directly connected to the motor.
1. The inlet pressure is sufficient, the gear must rotate, and there is no problem in passing. 2. Get a bypass and solve all problems.