Applications and Working Principle of Slurry Pumps

Working Principle of Slurry Pumps

The working principle of centrifugal pumps is basically the same as that of other centrifugal equipment. As slurry pumps fall into the category of centrifugal pumps, they generate a much higher pressure head than many other types of pumps, which makes their structure relatively complex.

First, let us clarify the relationship between centrifugal pumps and slurry pumps, after which the working principle of slurry pumps will become self-evident. The term "centrifugal" is defined based on the operating principle of the pump. Pumps can be classified into dozens of categories according to different criteria. Centrifugal pumps are categorized by their working principle—they boost the pressure of the conveyed medium through the action of centrifugal force. In addition, there are common types of pumps based on other principles such as the screw principle and plunger principle, which are different from centrifugal pumps.

After defining centrifugal pumps, we move on to slurry pumps. Slurry pumps are classified from another perspective—by the conveyed medium. As the name implies, slurry pumps are used to transport mixtures of water and solid particles containing residues. In terms of working principle, however, slurry pumps are a type of centrifugal pump. This clarifies the two concepts.

 Working Principle of Centrifugal Pumps & Overview of Slurry Pumps

The main working components of a centrifugal pump are the impeller and casing. The impeller installed inside the casing is mounted on a shaft and connected to a prime mover to form an integrated unit.

When the prime mover drives the impeller to rotate, the blades in the impeller force the fluid to spin. In other words, the blades do work on the fluid in the direction of its movement, thereby increasing the pressure potential energy and kinetic energy of the fluid. At the same time, driven by inertia, the fluid flows from the center to the edge of the impeller, exits the impeller at high speed, enters the discharge chamber, and is then discharged through the diffuser pipe. This process is called the pressure-raising process.

Meanwhile, as the fluid at the impeller center moves toward the edge, a low-pressure zone is created at the impeller center. When a sufficient vacuum is formed in this zone, the fluid flows through the suction chamber and into the impeller under the action of pressure at the suction end (usually atmospheric pressure). This process is called the suction process. With the continuous rotation of the impeller, the fluid is continuously discharged and sucked in, enabling the pump to operate continuously.

The working process of a centrifugal pump (including slurry pumps) is essentially a process of energy transfer and conversion. It converts the mechanical energy generated by the high-speed rotation of the motor into the pressure energy and kinetic energy of the pumped fluid through the pump blades.

A slurry pump, as the name suggests, is a type of centrifugal pump designed to convey slurries containing large-grained impurities, or abrasive and corrosive particulate impurities. Its typical performance parameters are as follows:

Flow rate Q: 30–1900 m³/h

Head H: 7–230 m

Slurry pumps are available in single-stage, horizontal cantilever configurations. The pump body adopts a double-layer structure consisting of an inner shell, a volute, and guard plates, with the flow passage components made of high-chromium alloy for enhanced wear resistance. The slurry pump uses a combined shaft seal with an auxiliary impeller and packing, which delivers favorable sealing performance.

Application Scope of Slurry Pumps

Slurry pumps are commonly used in scenarios such as:

Ash removal systems in thermal power plants for discharging slag slurry

Coal preparation plants for conveying coal slurry

Mines for discharging mineral slag