Robbins & Myers 330-2608-002 Nitrile Stator for Moyno 500 Model 633
The 330-2608-002 is the NBR nitrile stator for the Moyno 500 Models 63301 and 63311 progressing cavity pump. The stator is the molded elastomer element that lines the pump body, and it is one half of the pumping element. The steel rotor turns inside it, and the sealed cavities formed along the contact line between the two carry liquid steadily from the suction end to the discharge end without churning or pulsing it.
A stator is a wear part by design. The rotor is in constant sliding contact with the bore, so over time the interference fit relaxes and liquid begins slipping backwards through the cavities instead of being carried forward. The pump still turns and still primes, but it no longer reaches the pressure it used to and the flow falls away. Matching the elastomer to the liquid matters as much as matching the part number: NBR nitrile is rated for a service range of roughly 10 to 160 F, and a liquid that attacks the compound will swell, soften or harden it long before abrasion would have worn it out. The 633 pumps are rated to 150 psig through 1-1/4 in NPT suction and discharge connections, so stator condition is what holds that pressure.
Key Features
- Genuine Robbins & Myers Moyno replacement stator
- NBR nitrile elastomer construction
- Molded for the Moyno 500 Models 63301 and 63311 pumping element
- Restores the rotor to stator interference fit that sets discharge pressure
- Brings flow and pressure back to the original duty point
- Approximate elastomer service range of 10 to 160 F
- Direct replacement with no machining or modification
Applications
- Moyno 500 Models 63301 and 63311 progressing cavity pumps
- Restoring flow and discharge pressure that have fallen away gradually
- Rebuilding a pump after a dry running incident
- Changing elastomer compound to suit a different liquid
- Scheduled overhauls on metering and transfer duties
- Industrial, marine, dockside and washdown installations
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Manufacturer Part Number: 330-2608-002
- Part Type: Stator, progressing cavity pumping element
- Material: NBR nitrile
- Elastomer Service Range: approximately 10 to 160 F
- Quantity Used: One per pump
- Fits: Moyno 500 Models 63301 and 63311
- Condition: New
Frequently Asked Questions
Q: Should the rotor be replaced at the same time?
If the rotor still has intact plating and no scoring it can be reused. Once the plating has worn through, the exposed base metal is rough enough to chew through a new stator quickly, so at that point the pair should be changed together.
Q: Can the pump be left standing full of liquid between runs?
Liquid sitting in the stator causes no harm. A pump left standing dry for a long period is the greater risk, because the elastomer can take a permanent set against the rotor. Turning the shaft by hand from time to time avoids that.
Q: Can the stator be changed without unbolting the pump from its base?
On the smaller Moyno 500 pumps the suction housing and stator come off the front while the pump stays bolted down, which is quicker than breaking the drive coupling. Leave clear space in front of the pump at least equal to the length of the stator so it can be drawn straight off.
Q: Why is a new stator so much harder to assemble than the old one?
That resistance is the interference fit doing its job, and a fresh stator will always be tighter than the worn one that came out. Water or a compatible lubricant on the rotor makes assembly easier. Avoid oil and grease unless the compound is known to tolerate them.
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 stator before you order.
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