Measures to prevent overload of clean water centrifugal pump
In general, the first choice for clear water transportation is of course the clear water centrifugal pump. This can also be regarded as a relatively common pump in our lives, but it will also be overloaded during use, so today we will take a look at the clear water centrifugal pump overload. Reasons and preventive measures.
Clear water centrifugal pump overload reason analysis:
1, selection problem
Pump selection parameters are incorrect, and the surplus head is too much, which causes the working point of the clean water centrifugal pump to move to the right, the flow increases, and the motor load increases, which exceeds the rated current of the clean water centrifugal pump motor.
It is recommended to adjust the pump head, reduce the surplus head of the pump, recalculate the model selection, and remove the excess pump head.
2, multi-stage pump quality problems
The pump shaft is bent or the pump's various rotor parts run out too much in the radial direction, causing the pump shaft, bushing, guide vane, impeller, and sealing ring to rub against each other during the contact operation of the pump rotating body and the casing, resulting in The pump operating load has increased and the multi-stage pump is overloaded.
It is recommended to return the pump to the factory for maintenance, disassemble the pump, and check the radial runout of the pump shaft and multi-stage pump rotor. If the pump shaft is bent, it needs to be straightened. If the pump has too much radial runout, then it needs to be straightened. Replace or repair parts with too large radial runout until the design requirements are met.
3. The balance plate tilts too much
The pump balance plate axially jumps too much. After the pump runs normally, the balance plate and the balance plate rub against each other locally, which increases the pump motor power.
It is recommended to replace the qualified balance disc device to make the pump balance disc device meet the design requirements.
4, the impeller spacing is uneven, and the pump assembly quality is not good
The impellers of the pump are not evenly spaced, causing the individual impellers, middle sections or sealing rings of the multi-stage pump to rub against each other, increasing the motor load of the multi-stage pump. After disassembling the multi-stage pump, if the individual impellers of the pump are found to be seriously worn, this situation is The pump impeller spacing is uneven, so when assembling the pump, it is necessary to ensure the assembly quality of the pump and ensure that the pump impeller spacing value is within the design requirements.
Measures to prevent the overload of the clean water centrifugal pump:
1. Hydraulic coupling is used
Choosing a hydraulic coupling can prevent the overload of the clean water centrifugal pump from occurring, and enable the clean water centrifugal pump to operate under high pressure. The hydraulic coupling is generally installed between the clean water centrifugal pump and the motor. When the pump is operating normally, the hydraulic The power coupling transmits the rated torque from the motor end to the pump. The maximum pressure difference of the pump is determined by the maximum torque transmitted by the hydraulic coupling, while the maximum torque that the hydraulic coupling can transmit is adjusted by the amount of liquid in it. , When the pump works under high pressure difference or starts at the same time with the front pump, there is a speed difference in the liquid coupling, that is, slip, and only a certain torque is transmitted to make the pump work at a reduced speed. As the pumping progresses, the gas load decreases and the pump gradually accelerates to the rated speed.
2, using vacuum electrical components
Select vacuum electrical components to control the pump inlet pressure, and place pressure sensitive components such as a vacuum bellows relay or electrical contact vacuum pressure gauge at the inlet of the multi-stage pump. After the pump is started, when the pressure at the pump inlet is lower than a given value (multi-stage pumps allow When starting pressure), the pressure sensitive element sends a signal to start the pump through the pump electrical system (for example, if a bypass pipeline is installed in a multi-stage pump system, the bypass pipeline valve must be closed at the same time), but if the pump inlet pressure is higher than When the specified value is set, the multi-stage pump electrical system automatically shuts down the pump and opens the pump bypass valve at the same time to ensure the normal operation of the pump.
3, using mechanical automatic pressure regulating bypass valve
The bypass valve is generally installed on the bypass pipeline between the outlet and inlet of the multi-stage pump to control the pressure difference between the inlet and outlet of the multi-stage pump not to exceed the rated value. When the pressure difference reaches the rated value, the pump valve depends on the pressure difference The function is automatically opened to make the pump outlet and inlet communicate, and the pressure difference between the pump inlet and outlet is rapidly reduced. At this time, the pump is almost running under no pressure difference load. When the pressure difference is lower than the rated value, the pump valve closes automatically , The gas in the pump is pumped by the fore-stage pump through the multi-stage pump, and the pump with the bypass overflow valve can be started at the same time as the fore-stage pump, making the operation of the pump unit easier and more convenient.
