How to select a slurry pump: the seven data points we ask for

When a slurry pump underperforms, the cause is usually the data behind the selection rather than the pump itself. Seven numbers decide almost everything about the recommendation. If you can supply them, the shortlist is quick; if you cannot, the answers below explain what we will ask next.

1. Flow rate at the duty point

Not the maximum the pipe could carry — the flow the process actually needs. Slurry pumps are sensitive to running far from their design point: too far left and the solids settle in the casing, too far right and you overload the motor and wear the wet end out quickly.

2. Total head

Static lift plus discharge pressure plus friction losses, including the slurry’s higher density and the extra losses that come with solids. Water-based calculations consistently under-estimate the head for a dense slurry.

3. Solids concentration

By weight, and if possible by volume. This drives the motor size, the shaft seal arrangement and the choice between a heavy-duty and a light-duty casing. A pump quoted on water duty will overload when it meets a 40% solids stream.

4. Particle size and shape

Two slurries at the same concentration behave completely differently if one carries sharp, coarse particles and the other fine, rounded ones. Sharp particles wear alloy liners quickly; fine rounded ones are often better handled by rubber, which absorbs the impact.

5. Medium chemistry: pH, chlorides, temperature

These determine whether alloy, rubber, ceramic or a fluoroplastic-lined pump is appropriate, and which seal arrangement will last. Temperature also sets the limit for the lining and the gland arrangement.

6. Installation layout

Horizontal with a flooded suction, vertical sump, submersible, or in-line in the pipe run. The same hydraulic duty can need a different pump body entirely depending on where it has to sit and how much space the plant can give it.

7. Power supply and duty cycle

Voltage, frequency and available motor rating — plus whether the pump runs continuously or intermittently. Intermittent duty changes the start-up behaviour and the settling risk in the suction line.

What we do with the numbers

With these seven points we can confirm the series, choose the wetted-part material, size the motor against the slurry density rather than water, and quote the wear-part set that matches the expected life. Anything less and the recommendation carries an assumption — which is worth knowing about before the pump is on site.