Tuthill 20388902 Bearing Shim for HD Series Rotary Lobe Pumps
The Tuthill 20388902 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. Nothing else in the pump does that job, which is why the parts list treats shims as an as required item rather than a fixed quantity.
The three published thicknesses of 0.002, 0.005 and 0.015 inch are meant to be stacked to reach a target, which is why the parts list gives no fixed count. Confirm the thickness you need against the clearance figures for your pump size and duty before ordering. Handle shims carefully. A creased or burred shim does not sit flat, and a stack that does not sit flat gives a clearance that is not what the measurement says it is.
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: 20388902
- 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 the clearance is too tight?
The pump will run when cold and tighten as it warms, because the parts grow. That ends in contact between the impellers and the housing.
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.
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.
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