Pumps
Centrifugal and positive-displacement pumps for water supply, irrigation, process transfer, dosing and pressure boosting. Selection is by duty point and by what is in the liquid, in that order.
The type follows from the fluid. A centrifugal pump moves large volumes of thin liquid efficiently and is the right answer for clean water, cooling circuits and general transfer — but its flow falls as head rises, so it cannot hold a rate against a varying discharge. A positive-displacement pump delivers close to the same volume per revolution regardless of pressure, which is what dosing and viscous transfer need, and what makes it the wrong choice for high-volume low-head duty.
Mechanical seal against packed gland is the other decision that gets skipped. A mechanical seal runs dry-clean and needs no adjustment; packing needs a controlled drip and periodic tightening but tolerates abrasives that would score a seal face in weeks.
See the parent Pumps & Blowers page for how to establish a duty point. Sourced to order — send flow, head, medium and temperature.
Lines in this category
- End-suction centrifugal
- Multistage booster
- Submersible
- Self-priming
- Gear and lobe pumps
- Diaphragm and dosing pumps
- Peristaltic pumps
- Vertical inline pumps
Products
We source this line to order
We do not hold this category in stock, and we would rather say so than list parts we cannot ship. Send a part list, a specification or a photograph and we will quote it with a lead time — this is a line we supply regularly to order.
How to choose
Fluid first, because it decides the type: thin and clean, centrifugal; viscous, shear-sensitive or metered, positive displacement. Then the duty point, and check it against the curve rather than the nameplate. Then the seal — mechanical for clean duty, packed gland where abrasives are present. Then materials in contact with the fluid, including the gasket and the seal faces, which are usually the first thing a chemical attacks and the last thing anyone specifies.
Frequently asked
Centrifugal or positive displacement?
Centrifugal for large volumes of thin, clean liquid at a fairly steady head. Positive displacement when the fluid is viscous, when the flow rate must stay constant regardless of pressure, or when you are dosing a measured amount.
Mechanical seal or packed gland?
Mechanical seal for clean liquids — no adjustment, no drip. Packed gland where the liquid carries abrasives, because grit will score a seal face in weeks but packing can be tightened and eventually replaced cheaply.
Do you supply pumps with the motor fitted?
Yes, as a close-coupled unit or on a base plate with a coupling and guard. State the supply voltage and phase, and whether you need an IE-rated efficiency class for a tender.