Stator and rotor: the wear part in a screw pump
In an eccentric screw pump, a steel rotor turns inside a rubber stator. Everything the pump does happens where the two meet, and that is also where the wear happens. The rotor and stator are therefore a pair, and in practice they determine both the pressure and the volume the pump can deliver.
·
The figures in the range
The KTR range we stock covers a wide span, and the three figures are linked to each other and to the pump the part is fitted in:
- Installation diameter 50–300 mm
- Pressure 5–140 bar, depending on pump type
- Capacity 200–20 000 l/h, depending on speed
The pressure depends on the type of stator and rotor, the volume on the speed
Note the caveats in the specification: the pressure is “depending on pump type” and the capacity “depending on speed”. This means that the achievable pressure depends on the type of stator and rotor, while the volume depends on how fast the rotor turns.
That is why the starting point when ordering the part is the pump, not the desired pressure.
The rotor: material and surface
The rotor is supplied in through-hardened tool steel, in less expensive carbon steel variants, or as a custom solution. For demanding applications, the surface can be hard chrome plated or salt-bath nitrocarburised.
The choice here comes down to what is being pumped. KTR adapts the choice of material and the rubber compounds to the application, so it is worth stating what the pump actually handles when you order the part.
The stator: three versions
The stator comes in three versions: maintenance-free, slotted or adjustable.
Anti-rotation protection can be ordered as an option. If the stator has previously twisted round in the housing, mention this when ordering the replacement.
What we stock
The catalogue puts it like this: we stock the most commonly used stators and rotors for most pumps, pump trucks, filler trucks and grout and mortar pumps. The parts are made in Germany.
When you order
If you do not have the part number, the machine, serial number and a description are enough. For the stator and rotor, it also helps to state the installation diameter and whether the stator currently fitted is maintenance-free, slotted or adjustable. Call parts sales, or order using the form.
If you are also considering the pump itself, there is a separate guide on choosing a mortar pump.
The machines this guide covers
More guides on parts and service
Chisels for stone: the shank must fit the hammer
When a chisel is to be replaced, it is not the tip that decides whether the part fits. It is the shank — the end that sits in the hammer.
Read the guideJun-Air compressor maintenance: oil, condensate and filters
On Jun-Air's oil-lubricated compressors, the oil level, the condensate in the tank, the filters and any leaks must be checked regularly.
Read the guideGast vacuum pumps and blowers: filters, vanes and inspection
On Gast's regenerative blowers and oil-free piston pumps, check the filters after the first 500 operating hours and use what you find to decide how often they should…
Read the guideNeed help choosing the right machine?
Get in touch for advice, prices and availability — we respond quickly.