Robbins & Myers 330-4609-000 416 Stainless Rotor for Moyno 500 Model 633
The 330-4609-000 is the chrome plated 416 stainless steel rotor for the Moyno 500 Models 63301 and 63311 progressing cavity pump. It is the single helical screw that turns inside the elastomer stator. As it rotates it does not simply spin on its own axis but orbits within the stator bore, and the sealed cavities that action creates travel from suction to discharge carrying the liquid with them.
Rotors wear from the outside in. Abrasive particles polish and then cut the crests of the helix, and on plated rotors the plating eventually breaks through and exposes softer base metal underneath. From that point the rotor becomes the abrasive, and it will destroy a new stator far faster than normal service would. A rotor with visible scoring, a dull patchy surface or measurable flats on the crests has reached the end of its useful life. Stainless rotors resist corrosion well but are not immune to abrasion, and grit is what usually finishes them. The 633 pumps are rated to 150 psig through 1-1/4 in NPT connections and run on the same heavy duty chrome plated rotor design as the rest of the 600 Series.
Key Features
- Genuine Robbins & Myers Moyno replacement rotor
- chrome plated 416 stainless steel construction
- Profiled for the Moyno 500 Models 63301 and 63311 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 Models 63301 and 63311 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: 330-4609-000
- Part Type: Rotor, single helix progressing cavity
- Material: chrome plated 416 stainless steel
- Quantity Used: One per pump
- Fits: Moyno 500 Models 63301 and 63311
- 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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