Tuthill 20388901 Bearing Shim for HD Series Rotary Lobe Pumps
The Tuthill 20388901 is a genuine bearing shim for Tuthill HD Series rotary lobe process pumps. Shims are what set the axial position of the shafts in a rotary lobe pump, and that position is what holds the impellers clear of the faceplate and the housing. It is the least glamorous part in the pump and the one that decides whether the rebuild works.
Setting an HD Series pump is a matter of shimming the bearing carriers until the impellers clear the faceplate and the housing by the published amount, then locking that position. Too little clearance and the pump seizes as it comes up to temperature, too much and the capacity falls away. Work from the clearance figures for your pump size rather than from the shim stack that came out, because the old stack reflects the wear that has since happened.
Key Features
- Genuine Tuthill bearing shim
- Direct replacement for HD Series bearing carriers
- Published in 0.002, 0.005 and 0.015 inch thicknesses across the family
- Listed on the parts list as an as required item
- Sets the axial shaft position that holds impeller clearance
- Stacked to reach a measured target rather than fitted to a fixed count
Applications
- Viscous and abrasive slurry transfer
- Corrosive acid and chemical process duty
- Fluids carrying suspended solids that must not be sheared
- Heavy process oils, resins and adhesives
- Scheduled overhaul of Tuthill rotary lobe process pumps
- Critical spares holding for continuous process plant
Specifications
- Brand: Tuthill
- Manufacturer Part Number: 20388901
- Part Type: Bearing Shim
- Fits: Tuthill HD Series rotary lobe process pumps
- Quantity Required: as required
- Condition: New
Frequently Asked Questions
Q: What happens if it is too loose?
Capacity falls away, particularly on thinner fluids, because the fluid slips back past the impeller ends instead of being carried around.
Q: Do I need shims if only a seal is being changed?
Not usually, as long as the bearing carriers have not been disturbed. If they have, the clearance has to be checked again.
Q: Are shims interchangeable between pump sizes?
No. Each pump size has its own shim, and a shim from a neighboring frame will not sit correctly in the carrier.
Q: How many shims will I need?
There is no fixed answer. The count comes from the clearance measurement on your pump, which is why the parts list calls them an as required item.
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 shim.
CLRMarine
