Impeller arrangement in multi-stage centrifugal pumps

The horizontal multi-stage centrifugal pump features a single-suction, multi-stage segmented structure; its inlet is horizontal while the outlet is oriented vertically upward. It is primarily composed of an inlet section, intermediate sections, guide vanes, impellers, an outlet section, as well as bearing units and sealing components. Installation sequence: (1) Deliver the unit to the site; if it comes with a base, the motor is already installed. The water pump and motor do not need to be removed when leveling the base. (2) Place the base on the foundation, and insert wedge shims near the foot screws to lift the base by 20~40 millimeters, ready for leveling before filling with cement slurry. (3) Use a level to check the levelness of the base; after leveling it, tighten the foot nuts and fill the base with cement slurry. Once the cement has dried, check the levelness again. (4) When the unit’s power is high, for the purpose of facilitating transportation, the pump, motor, and base may be packaged separately; in such cases, the user is required to install and adjust the water pump unit by themselves. The method is as follows: a. Clean off any dirt from the supporting surfaces of the base, as well as from the surfaces where the pump feet and motor feet rest, and then place the pump and motor on the base. b. Adjust the level of the pump shaft; after leveling it, tighten the nuts appropriately to prevent movement. c. Lift the motor so that the pump coupling and the motor coupling fit together, then lower the motor to its proper position. d. Adjust the gap between the two couplings to around 5 mm, and check whether the axis lines of the motor shaft and the pump shaft are aligned. To do this, place a straight edge on the couplings; the outer surfaces of both couplings should be level with the straight edge. If they are not aligned, adjust the relative positions of the motor or the pump, or use shims to make the adjustment. e. To verify the accuracy of the installation, measure the gap between the surfaces of the couplings at several different points around their circumference using a feeler gauge. The maximum difference in gap across the entire circumference of the couplings should not exceed 0.3 mm, while the difference up and down or left and right along the central axis should not exceed 0.1 mm. (5) When the unit is not equipped with a base, it must be installed directly on the foundation. The method is similar to that in 4, but greater attention should be paid to alignment. Precautions for installation: 1. During installation, the weight of the pipelines should not be borne by the pump, as this can easily damage it; 2. The foot bolts must be tightened properly during installation, and the pump should be checked at regular intervals to ensure they remain tight, thereby preventing severe vibrations when the pump starts, which could affect its performance; 3. Before installing the pump, it is necessary to carefully check whether there are any hard objects (such as stones or iron particles) inside the pump’s flow channels that could damage the components while the pump is in operation; 4. For ease of maintenance and safety, a control valve should be installed on the inlet and outlet pipelines of the pump, as well as a pressure gauge near these connections. For pumps with high head pressures, a check valve should also be installed in front of the outlet valve to prevent water hammer effects in case of sudden power loss, thus ensuring that the pump operates under optimal conditions and extending its lifespan; 5. When the pump is used in applications that require lifting capacity, it should be equipped with a bottom valve. The inlet pipeline should have as few bends as possible, and there should be no leaks of water or air, as these can affect the pump’s suction performance; 6. To prevent impurities from entering the pump and blocking the flow channels, a filter should be installed before the pump’s inlet; 7. Before installing the pipelines, the rotor components of the pump should be rotated – there should be no friction or sticking. If such issues exist, the pump needs to be disassembled to determine the cause.