Regarding the pump, turn it on
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I have been working in the chemical industry for over two years, almost three now, and I have some understanding of pump startup. However, the training on Diqi pumps has had a significant impact on me! ! ! ! ! ! First, carry out inspections on the centrifugal pump: check the wiring, the cleanliness of the oil, the oil level, and the foot bolts. Second, rotate the pump manually. Third, if the inlet valve is normally open, there’s no need to operate it; the main task is to fill the pump with oil. Fourth, start the pump and open the outlet valve to allow exhaust gas to flow out; gradually open the outlet valve. In this factory, the inlet and outlet valves of the centrifugal pumps are kept fully open before starting the pump – just ensure that the flow path is unobstructed before initiating operation. I reminded the staff that it’s not necessary to reverse the direction of the pump’s rotation, and that they should pay attention to exhausting air if the pump will be shut down for an extended period of time! Also, keep the inlet and outlet of the plunger pump fully open, start the pump. Where I used to work, I would start the pump and check the pressure reading; it was necessary to release air from the system! Let’s all talk about it
The outlet should be closed when the pump stops operating. Before starting the pump, air should first be exhausted, then the pump should be started, and subsequently the outlet valve opened.
When starting a centrifugal pump, the outlet valve should be closed to minimize the starting current and protect the motor; it should be opened gradually after the pump is started
The common types of pumps that are started in this way are rotor pumps and positive-displacement pumps; their starting methods are exactly opposite to each other. Centrifugal pump: Open the inlet valve to start the pump and gradually open the outlet; for positive displacement pumps, open the outlet fully and gradually open the inlet (the inlet can be opened to a smaller degree in advance) ； However, I believe it is necessary to analyze each specific pump individually. For example, in centrifugal pumps, such as high-pressure pumps (multi-stage pumps, high-speed pumps), the outlet valve still needs to be opened before starting the pump (usually there is a reverse flow line), and the degree of opening depends on the pump’s head value; pumps with relatively low heads can have the valve opened to a smaller degree, while those with higher heads should have the valve opened to a level close to the pump’s normal flow rate. Such pumps are quite sensitive, with a narrow suitable flow range – if the valve is opened too much, the pump may experience vacuum conditions that can damage the rotor. On the other hand, if the outlet valve is opened too little, severe vibrations occur in the pump’s inlet and outlet pipelines, which is also very dangerous. Everyone needs to pay close attention.