Main Parts Of Stainless Steel Submerged Pump

Apr 26, 2022

(1) Impeller is the key component of the submerged pump. It can be divided into three types: closed, semi-closed and open. The closed impeller is suitable for conveying clean liquid; the semi-closed and open impellers are suitable for conveying suspension containing solid particles, which is inefficient.

According to different liquid suction methods, the impeller can be divided into single suction and double suction. The single suction impeller has a simple structure, and the liquid can only be sucked from one side. The double suction impeller can suck liquid symmetrically from both sides of the impeller at the same time. It not only has a large liquid suction capacity, but also basically eliminates the axial thrust.

According to the geometry of the blade on the impeller, the blade can be divided into backward bending, radial bending and forward bending. Backward curved blades are widely used because they are conducive to the conversion of liquid kinetic energy into static pressure energy; radial blades are mainly used in partial flow pumps and non-clogging pumps; forward curved blades are rarely used in submerged pumps.

(2) In order to reduce the energy loss caused by impact when the liquid leaving the impeller directly enters the pump shell, a fixed guide wheel with blades is sometimes installed between the impeller and the pump shell. The blades in the guide wheel gradually turn the liquid entering the pump shell, and the flow channel is continuously expanded, so that part of the kinetic energy is effectively converted into static pressure energy. Guide wheels are usually installed in multi-stage submerged pumps. Snail-shaped pump casing, backward curved blade on impeller and guide wheel can improve the conversion rate of kinetic energy to static pressure energy, so they can be regarded as energy conversion devices.

(3) For the shaft sealing device, the pump shell is fixed due to the rotation of the pump shaft, and there must be a certain gap at the contact between the shaft and the pump shell. In order to avoid the leakage of high-pressure liquid in the pump along the gap or prevent the outside air from entering the pump from the opposite direction, the shaft seal device must be set. The shaft seal device of submerged pump includes a stuffing box and a mechanical (end face) seal. Stuffing box is to make the pump shaft into a sealing ring through the annular gap of the pump housing, and install soft packing (such as asbestos rope soaked in oil or coated with graphite, etc.). The mechanical seal is composed of a moving ring installed on the rotating shaft and another static ring fixed on the pump shell. The end faces of the two rings are close to each other and rotate relative to each other by spring force, which plays a sealing role. Mechanical seals are suitable for occasions with high sealing requirements, such as conveying acid, alkali, flammable, explosive and toxic liquids.