Robbins & Myers 320-2424-000 Nitrile Mechanical Seal for Moyno 500 Models 331 to 344
This NBR nitrile mechanical seal closes the shaft opening in the Moyno 500 Models 331, 332, 333 and 344, all builds body. A seal of this type works through two lapped faces held together in light contact, one turning with the shaft and one static in the housing, with a thin film of the pumped liquid between them doing the lubricating.
The seal is normally renewed whenever the wet end is opened, because it is inexpensive next to the labor of reaching it and because a used seal rarely beds down properly a second time. Check the shaft itself while the seal is out: a groove worn where the old seal ran will cause the new one to leak however carefully it is fitted. NBR nitrile gives an approximate service range of 10 to 160 F. It is the nitrile seal used across the whole 331 to 344 range; EPDM and fluoroelastomer versions of the same seal carry their own part numbers.
Key Features
- Genuine Robbins & Myers Moyno replacement mechanical seal
- NBR nitrile elastomer
- Lapped face design lubricated by the pumped liquid
- Keeps pumped liquid away from the bearings and drive end
- Approximate elastomer service range of 10 to 160 F
- Direct replacement with no modification required
Applications
- Moyno 500 Models 331, 332, 333 and 344, all builds progressing cavity pumps
- Curing a leak or weep at the shaft where it leaves the pump body
- Routine renewal whenever the wet end is opened
- Rebuilding a pump after a dry running incident
- Changing elastomer compound to suit a different liquid
- Industrial, marine, dockside and washdown installations
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Manufacturer Part Number: 320-2424-000
- Part Type: Mechanical seal, shaft
- Material: NBR nitrile
- Elastomer Service Range: approximately 10 to 160 F
- Quantity Used: One per pump
- Fits: Moyno 500 Models 331, 332, 333 and 344, all builds
- Condition: New
Frequently Asked Questions
Q: Does the elastomer compound change how the seal is fitted?
No, the fitting procedure is the same. The compound governs which liquids and temperatures the seal tolerates, which is why the same seal is offered in more than one material under separate part numbers.
Q: The shaft has a visible groove. Can the seal still be used?
Not reliably. A new seal running in an old groove will leak, because the faces cannot follow the step. The shaft needs replacing, or in some builds a shaft sleeve or a repositioned seal is the accepted fix.
Q: A new seal leaked straight away. What usually causes that?
Three things account for most cases: a fingerprint or particle on one of the lapped faces, a groove worn into the shaft where the old seal ran, or the seal being pushed on dry so the elastomer rolled instead of sliding. Clean faces, a checked shaft and a little water on the elastomer solve nearly all of them.
Q: How much weeping is acceptable on this type of seal?
A trace of dampness while a new seal beds in over the first few hours of running is normal. A steady drip is not, and a seal that is still dripping after bedding in should be investigated rather than tightened.
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 mechanical seal before you order.
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