Centrifugal sewage pump

Abstract

The invention discloses a centrifugal sewage pump, mainly comprising a pump body, a pump shaft, an impeller, mechanical seal, a front end cover, a motor, a rear cover, and a control system. The pump is characterized in that the distance between the outer end face of the impeller in an impeller cavity of the pump body and an inlet is larger than hub thickness of the impeller, so that the gap between the pump body and a blade has a large channel holding cavity, and large diameter particles can pass through the large channel holding cavity. The impeller is formed by a hub, an impeller plate, and two helical blades. The impeller plate is fixed on one end of the hub, and the periphery of the impeller plate is provided with two helical blades. The initiating end of the helical blade is fixedly connected with the hub, and the bottom is fixed on the impeller. The helical cambered surface of the helical blade spans three quadrants from the initiating end along the surface of the impeller plate, and then the tail end is corresponding to the outer edge of the impeller plate. The sewage pump is characterized by no overloading in total head, convenient and fast when dismounting and changing the impeller, the mechanical seal, and cables, better sealing effect, higher complete machine stability, longer life, and flexible and diverse installation methods.

Description

technical field [0001] The invention relates to the technical field of mechanical engineering pumps, in particular to a centrifugal sewage pump. Background technique [0002] At present, the existing centrifugal sewage pump is mainly composed of a pump body, a pump shaft, an impeller, an impeller nut, a pump cover, a connecting seat, a double-end non-packaged mechanical seal, a bearing, a bearing gland, a rotor, a stator, and a casing. , upper end cover, junction box cover, cable, and cable compression screw cover. Its shortcomings: First, the pump body is a spiral volute, and the impeller structure has vane type, single channel type, and double channel type. Although these structures have higher throughput than ordinary vane centrifugal pumps, they are still limited. The passage capacity of the channel is relatively better, but the single-channel pump is not easy to cast, and the hydraulic imbalance caused by the asymmetry of the channel, even if the impeller is dynamicall...

AI Technical Summary

Problems solved by technology

Its shortcomings: First, the pump body is a spiral volute, and the impeller structure has vane type, single channel type, and double channel type. Although these structures have higher throughput than ordinary vane centrifugal pumps, they are still limited. The passage capacity of the channel is relatively better, but the single-channel pump is not easy to cast, and the hydraulic imbalance caused by the asymmetry of the channel, even if the impeller is dynamically balanced before the pump is installed, the water flow is also asymmetrical when the pump is running It is easy to generate vibration, noise, and even the pump fails to be used; although the double-channel impeller can solve the disadvantages caused by the asymmetry of the single-channel, the passing capacity of solid particles will be halved

There are also pump bodies and impellers with swirl structure in the existing products, but the structure of the impeller is multi-blade, generally 5~8, or even more than a dozen, and the shape of the blades is straight blades, or there is a small section of front blade at the outlet of the blades. Bending or backward bending, the characteristic curve of the flow and head of the pump with this structure is relatively flat, and the power curve rises quickly with the change of flow, which is prone to overpower phenomenon

Second, when replacing the impeller, it is necessary to disassemble the pump body, pump cover, and 4 or 6 connecting bolts of the connecting seat, which is time-consuming and laborious. At the same time, the mechanical seal will become loose, and the lubricating oil in the oil chamber also needs to be emptied in advance.

The third is that the pump cover and the connecting seat form a sealed oil chamber. The oil chamber is equipped with a double-end non-assembled mechanical seal or two independent single-end mechanical seals. The installation is time-consuming and laborious, and it is not easy to operate. The user needs to disassemble the impeller when replacing the mechanical seal on site. , pump cover, machine seal static ring, moving ring and other parts, one by one disassembly, the steps are cumbersome

The fourth is that the motor is an ordinary submersible motor, which is not easy to cool. It needs circulating water to cool down, and the wiring of the motor cable is relatively cumbersome. When replacing the cable, it is necessary to disassemble the junction box cover to perform wiring, and then install the junction box cover. It leads to more operation steps; fifth, the overall structure is either vertical or horizontal, and the vertical and horizontal cannot be converted to each other

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