Robbins & Myers 330-4604-000 416 Stainless Rotor for Moyno 42202 Grinder Pump
This chrome plated 416 stainless steel rotor is the metal half of the pumping element in the Moyno 500 Model 42202 grinder pump. Working against the molded stator it produces flow that is directly proportional to shaft speed, which is why these pumps meter so well and why they handle viscous and shear sensitive liquids that a centrifugal pump would spoil.
Because the rotor and stator work as a matched pair, condition of one governs the life of the other. Fitting a new stator over a worn rotor is false economy: the rough surface abrades the fresh elastomer bore within a fraction of its normal life. Replacing both together restores the interference fit properly and gives the rebuild a predictable service interval. Stainless construction suits corrosive and washdown duties as well as general transfer work. The 400 Series are grinder pumps rated to 35 psig, fitted with a carbide tipped cutter ahead of the pumping element, and they run submerged rather than self priming.
Key Features
- Genuine Robbins & Myers Moyno replacement rotor
- chrome plated 416 stainless steel construction
- Profiled for the Moyno 500 Model 42202 grinder pump pumping element
- Restores the seal line against the stator and the pressure the pump can hold
- Single helix geometry gives flow proportional to shaft speed
- Direct replacement with no machining required
Applications
- Moyno 500 Model 42202 grinder pump progressing cavity pumps
- Rebuilding a pump at the same time as the stator
- Replacing a rotor with worn plating, scoring or flatted crests
- Recovering lost discharge pressure after abrasive service
- Metering and transfer of viscous or shear sensitive liquids
- Industrial, marine and dockside pumping installations
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Manufacturer Part Number: 330-4604-000
- Part Type: Rotor, single helix progressing cavity
- Material: chrome plated 416 stainless steel
- Quantity Used: One per pump
- Fits: Moyno 500 Model 42202 grinder pump
- Condition: New
Frequently Asked Questions
Q: Is a stainless rotor interchangeable with a plated steel one?
They are supplied under separate part numbers because the materials suit different duties, so the correct one for your build is set by the pump model and the liquid rather than by preference. Send a picture of the pump plate and we will confirm which your pump takes.
Q: What should be checked at the drive end during a rebuild?
Look at the pin holes or joint connection for elongation and at the joint itself for play. A loose drive connection loads a new rotor unevenly and shortens the life of everything downstream of it.
Q: Can a worn rotor be replated rather than replaced?
It is done on large industrial pumps where replacement means a long wait, but on a pump this size it rarely makes sense. Plating alone does not restore the helix profile, and the grinding needed to bring the geometry back costs more than a new part.
Q: How do I tell a worn rotor from a corroded one?
Wear leaves smooth bright flats along the crests of the helix where the seal line ran. Corrosion and cavitation leave a rough pitted texture that looks eaten away. The first is normal service life, the second points at a chemistry or suction problem worth fixing first.
Not sure this is the right part? Send us a Picture of the pump plate on your pump and the CLR Marine team will confirm the correct rotor before you order.
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