Considerations for selecting self-priming centrifugal pumps

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The self-priming centrifugal pump features a pump body with an axial liquid return structure, which consists of a suction chamber, a liquid storage chamber, a vortex chamber, a liquid return hole, and a gas-liquid separation chamber. The pump’s bearings are single-row radial ball bearings. A cooling chamber is provided at the bottom of the pump’s bearing housing, and seal rings are present in the high-pressure and low-pressure sections inside the pump. Mechanical seals are used at the shaft ends. 　　Self-priming centrifugal pumps are equipped with a foot valve at the lowest point of the suction pipeline; before starting, a sufficient amount of water is needed to fill the entire suction pipeline. The foot valve often malfunctions due to the inclusion of debris or because it isn’t sealed properly, and resolving such issues can require a lot of effort, especially in winter. The suction inlet of a self-priming centrifugal pump is generally located above the impeller’s suction inlet; it can be started by filling water into the pump chamber, and it does not have the aforementioned drawbacks. Self-priming pumps are very convenient for tasks involving pumping water, moving equipment, frequent start-ups, and dealing with difficulties related to water injection. They are used in a wide range of fields such as agriculture, construction, unloading oil from tank trucks, oil depots, firefighting, and shipbuilding. 　　Selection principles for self-priming centrifugal pumps:
1. High mechanical reliability, low noise, and minimal vibration.
2. The type and performance of the selected pump must meet the process requirements regarding flow rate, head, pressure, temperature, cavitation flow rate, suction lift, etc.
3. Economically, it is necessary to ensure that the total cost—including equipment costs, operating costs, maintenance costs, and management expenses—is minimized.
4. Self-priming centrifugal pumps feature high rotational speed, compact size, light weight, high efficiency, large flow rate, simple structure, pulsation-free fluid delivery, stable performance, ease of operation, and convenient maintenance.
Self-priming centrifugal pumps are used to transport petroleum products such as gasoline, kerosene, diesel, and aviation fuel. With a medium temperature range of -20°C to +80°C, it is an excellent marine oil loading and unloading pump that can also be used as a bilge pump. It is also suitable for oil transfer in oil storage facilities such as land-based oil depots and tank trucks. It can also be used to transport seawater, fresh water, etc. It features a simple structure, easy operation and maintenance, stable operation, large displacement, high efficiency, easy adjustability, strong self-priming capability, and a wide range of applications.