Essential Parameters for Slurry Pump Selection

1. Basic Pump Parameters

Flow Rate (Q): The volume of liquid a pump can move in a specific amount of time. It's represented by the symbol "Q" and common units are liters per second (l/s) or cubic meters per hour (m³/h).

Head (H): This represents the energy gained by a unit weight of liquid after passing through the pump. Essentially, it's the height to which the pump can lift the liquid. It's represented by the symbol "H" and is measured in meters (m).

Speed (n): The number of complete revolutions the pump's shaft makes per minute. It's represented by the symbol "n" and its unit is revolutions per minute (r/min).

2. Power & Efficiency

Shaft Power (P): The power required from the motor to drive the pump. It's represented by the symbol "P" and measured in kilowatts (kW).

Effective Power (Pe): The useful power actually imparted to the liquid (or slurry) being pumped. It's calculated by multiplying the weight flow rate of the liquid by the head. Its symbol is "Pe" and it's also measured in kilowatts (kW).

Efficiency (η): The ratio of the Effective Power (Pe) to the Shaft Power (P). Represented by the symbol "η"(eta), it's a measure of how effectively the pump converts input power into useful output power for moving the fluid.

3. Special Considerations for Slurries

Slurry Shaft Power (Pm): The shaft power required by the pump when it is moving a slurry (a mixture of liquid and solid particles) instead of a clean liquid. Its symbol is "Pm" and it's measured in kilowatts (kW).

4. Net Positive Suction Head (NPSH)

Net Positive Suction Head (NPSH): The excess energy (per unit weight) a liquid has at the pump's inlet, over and above its vaporization (boiling) pressure. It's a crucial factor for preventing cavitation (the formation of damaging bubbles). Its symbol is "NPSH" and it is measured in meters (m).

5. Solid Material Properties in Slurries

Particle Size: The size of the solid particles within the slurry. Sizes are described as minimum size, maximum size, and a median size.

Median Particle Size (d₅₀): This is a key measurement representing the particle size at which 50% of the sample's total weight is made up of particles larger than d₅₀ and 50% is made up of particles smaller than d₅₀. Think of it as the average particle size by weight. It's represented by “d₅₀” and units are typically millimeters (mm) or micrometers (μm).

The selection of slurry pumps is far from simply matching flow and head. It is a systematic project that directly affects production efficiency, operating costs, and equipment lifespan.