Cleark Seals, Ltd. | Engineered Sealing Solutions

Custom Designed & Manufactured Nitrile Mechanical Seal for a Washing Machine Tub

Clark Seals Ltd. was contacted by the largest manufacturer of commercial laundry equipment with a problem they were having with seals leaking in sandy environments. Sand was getting between the sealing surfaces of the mechanical seal, grooving the face and causing leakage.

To solve the problem, we designed a custom two-piece integrated sealing solution that sealed against the top and bottom of the tub. The top seal was designed to press-fit around the tub bearing to improve alignment between the transmission, tub and agitator and a triple sealing lip to prevent water, sand and debris from entering the bearing cavity. The bottom seal was designed with a locking pin to resist torque and press-fit into the top seal during installation. To further reduce sand and other contaminants, our engineers developed and patented a unique negative "R"; sealing lip geometry that allowed the sprung lip to perform as an excluder lip and keep all sand out of the sealing environment.

The end result was a patented sealing solution that eliminated warranty claims, cost 80% less and lasted more than 700% longer than the mechanical seal it replaced.

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Custom Designed & Manufactured Seal Specifications

Product Name
Washing Machine Tub Seal
Product Description
Custom two-piece integrated washing machine tub seal.
Capabilities Applied/Processes
Problem Seal Analysis
Application Engineering
Custom AutoCAD Seal Design
Precision Manufacturing
Manufacturing Equipment Used
Commercial Vertical Washing Machine
Overall Dimensions of the Seal
Ö3.630x1.150 (OD xH assembled dimension)
Tightest Tolerances Met
RMA standards, .001"
Material Used
METALCASE: Carbon steel
SPRING:Stainless steel
Shroud:Stainless Steel
GREASE:Mobilith SHC 100 Red grease
Bottom Seal:
  • Designedw/ Locking Pin to Resists Force from Torque
  • Two Sealing Areas Molded to the Metal Case
    • One Sealing Against the Bottom of the Tub
    • One Oval Hard Rubber Seal, Sealing Against the Opening of the Tub
  • Designed to Press Fit Into Top Tub Seal to a Specific Depth During Semi-Automated Assembly
  • Designed to drain water
Top Seal:
  • ThreeS ealing Lips Prevents Water, Sand & other Debris from Entering Bearing Cavity
  • Pre Greased Prior to Shipping
  • Face:.35 Grams of
  • Between Spring Lip & Un-Sprung Lip: .20 Grams
  • Between 2 Unsprung Lips: .45 Grams
  • Rough seal OD to improved adhesive bounding
Designed & Patented Negative "R" Lip Geometry:
  • Allows Sprung Lip to Act as an Excluder Lip
  • Extends Life of the Seals
Custom Designed Grease Dispensing Head:
  • Accurately Dispenses Correct Amount of Grease Between Each Sealing Lips
Eliminated Warranty Claims
80% Cost Savings
Lasts 700% Longer than the Seal it Replaced
In process testing performed
Inspected Each Assembly
  • After Insertion of the Bearing into the Bottom Seal for Rotation and Assembled Dimensions
Customer Life-Test
Estimated Part Weight
Standards Met
Elastomer spec.: SAE J200, JMLU2 and UL157
Metal case material spec.: SAE 1008
Spring material spec.: SAE 30304
Industry for Use
Laundry Equipment
Delivery Location

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