What is A Centrifugal Dredge Pump? Overview of Dredge Pump Parts Function

?Centrifugal Dredging Pump is a kind of pump that uses centrifugal force generated by the rotation of an impeller to convey pipes. Centrifugal pumps have a wide impact on various fields, such as sewage treatment, sand pumping, dredging, mud dredging and pipeline industries. They have the characteristics of compact structure, wide flow adjustment range and smooth operation. Stability and other characteristics.

The centrifugal sand pump mainly consists of the following parts:

1. Sand pump impeller :

This is the core part of the centrifugal sand pump. It usually consists of 6 to 12 backward-curved blades, which are installed on the pump shaft and placed inside the pump casing. When the impeller rotates at high speed, it converts mechanical energy into kinetic energy and pressure energy of the liquid. The following is a detailed description of the centrifugal sand pump impeller:

The impeller of the centrifugal sand pump is mainly composed of the following parts:??

Blades: The curved blades are the core part of the impeller. They are fixed on the hub and generate centrifugal force through rotation.

Front cover: The cover located in front of the impeller is connected to the front end of the blades and forms the first barrier for fluid entry.

Rear cover plate: The cover plate located behind the impeller, connected to the rear end of the blade, restricts the direction of fluid flow.

Hub: The central component that connects the blades to the pump shaft, supports the blades and transmits rotational power.

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Impellers are roughly divided into three types according to their structural characteristics:

Closed impeller: The blades are completely surrounded by front and rear covers, suitable for transporting clean liquid without solid particles, and have high efficiency.

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Semi-open impeller: At least one side of the front or rear cover is open, which is suitable for liquids containing a certain amount of suspended solids to facilitate the passage of solid particles.

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Open impeller: no front and rear covers, only the blades are directly fixed on the hub, suitable for liquids containing a large amount of solid particles or fiber materials such as mud, sand, stones, etc.

Leaf form:

Back-curved blade type: The most common type, the blade bending direction is the same as the impeller rotation direction, which can provide higher head and lower flow rate, and is suitable for high-pressure head applications.

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Twisted blades (double curvature blades): The blades are twisted along the length direction, which can optimize fluid flow, improve efficiency, and reduce vibration and noise.

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Impeller material: The material of the impeller is selected according to the nature of the pumped liquid and the working conditions. Common ones include cast iron, stainless steel, engineering plastics, etc. For example, for corrosive liquids, corrosion-resistant materials such as stainless steel or special plastics are chosen. If it is used for dredging or sand pumping, we will choose high chromium alloy with a chromium content of 26%, 28% which is more wear-resistant and a ?hardness of 60 degrees. If it contains chemical substances such as acidic water with a pH value of 4-5, We recommend using Cr30 material. Compared with stainless steel 316, Cr30 has better wear resistance.

Impeller design considerations:

Number of blades: usually between 6 and 12. Increasing the number of blades can increase the lift, but at the same time it will increase friction loss and reduce efficiency.

Flow channel design: Reasonable flow channel design can reduce flow resistance and improve pump efficiency and performance.

Balance: The design of the impeller needs to consider the balance of axial forces to avoid excessive load on the pump shaft and bearings.

2.?Pump body (pump casing) : As the main body of the sand pump, it plays a supporting and fixing role, and is connected to the bracket where the bearing is installed. The shape of the inner cavity of the pump casing is designed to facilitate the flow of liquid and collect the liquid absorbed in the impeller.

Structural features: The volute usually has a spiral or gradually expanding channel design, forming a snail shell, hence its name. This design gradually increases the cross-sectional area of the flow channel from the outlet of the impeller to purify the discharge port of the pump.

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Pump shell functions:

Energy conversion: When the impeller rotates, the high-speed rotating liquid is thrown out of the impeller and enters the volute. As the flow channel gradually expands, the flow rate of the liquid slows down, and part of the kinetic energy is converted into static pressure energy, thereby forming enough pressure at the outlet of the pump to overcome the system resistance and achieve effective transportation of the liquid.

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Fluid guide??:?The volute not only provides a gradual deceleration channel for high-speed flowing liquid, but also ensures the orderly flow of liquid, avoids turbulence and energy loss, and improves the working efficiency of the pump.

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Collection and discharge: The volute collects the liquid thrown from the impeller, collects it, and guides it to the outlet pipe of the pump. This design ensures that the pump can deliver liquid continuously and stably.

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Exhaust function: During the initial start-up of the sand pump, the volute also helps to remove gas from the pump chamber to ensure that the pump chamber is filled with liquid to avoid damage and low efficiency caused by idling.

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Stability: The design of the volute helps balance the radial force generated by the rotation of the impeller, reduce vibration and noise during pump operation, and increase the operational stability of the pump.

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Materials and manufacturing: The volute is usually made of cast iron, stainless steel or other corrosion-resistant materials to adapt to the chemical properties and temperature conditions of different working media. Material selection also needs to take into account wear resistance and strength to extend the service life of the pump.

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3.Guide wheel : The guide wheel in a centrifugal pump, also called a diffuser or volute, is a fixed component with blades, usually installed behind the impeller and inside the pump casing. Guide pulleys are particularly common in multistage centrifugal pumps, especially where high lift is required or high efficiency is required. Single-stage centrifugal pumps may also be equipped with guide wheels as needed to optimize pump performance. Generally, dredging pumps are used as relay pumps.

Its main functions and characteristics are as follows

Energy conversion: The function of the guide wheel is to further convert the kinetic energy of the liquid in the impeller into static pressure energy. When the high-speed flowing liquid comes out of the impeller, it enters the enlarged channel of the guide wheel. The gradual increase in the channel slows down the flow rate of the liquid and increases the pressure of the liquid. This process reduces the loss of kinetic energy and increases the total pressure of the pump. head.

Reduce energy loss: By smoothly changing the direction of liquid flow and slowing down the flow rate, the guide wheel can effectively reduce the energy loss caused by the liquid directly impacting the pump shell wall, reducing the formation of turbulence and vortices, and improving the efficiency of the pump.

Structural features: The blades inside the guide wheel are designed to guide the liquid to turn smoothly and flow through the enlarged flow channel. This design contributes to the continuity of fluid flow and makes energy conversion more efficient. The material of the guide wheel is usually the same as the pump casing, such as cast iron, stainless steel, etc., to adapt to different working environments and media.

4. Pump shaft : It is connected to the motor through a coupling and transmits the rotational motion and torque of the motor to the impeller. It is a key component for transmitting mechanical energy.

5. Bearing : supports the pump shaft and allows it to rotate smoothly. It is divided into two types: rolling bearing and sliding bearing to ensure the stability and efficiency of the pump operation.

6. Sealing device :?includes sealing ring (leakage reduction ring), mechanical seal and stuffing box, etc., to prevent the liquid in the pump from leaking outward and air from entering the pump, ensuring the normal operating efficiency of the pump.

7. Axial force balancing device : This component is included in some centrifugal pumps and is used to balance the axial force generated by the rotation of the impeller to ensure that the pump shaft will not be damaged due to excessive axial force.

In addition to the main components mentioned above, centrifugal pumps may also be equipped with other auxiliary components, such as:

8. Suction pipe and pressure pipe :?used to guide liquid in and out of the pump.

9 Bottom valve :?Installed on the suction pipe to prevent liquid backflow when the pump is stopped.

10 Control valve :?adjust the inlet and outlet flow of the pump.

11. Lubrication system : Provides necessary lubrication for sliding bearings.

12?Guards and Brackets?: Provides additional safety protection and structural support.

These components work together to allow centrifugal pumps to effectively lift liquids from low to high or pressurize them.

Witten by ：

TAIAN OCEAN PUMP CO.,LTD

DORIS CHEN

WWW.DREDGEPUMPCHINA.COM

EMAIL : [email protected]

WHATSAPP : +86 18562293319