Expansion Chambers

Expansion Chambers

Equalizer Expansion Chambers are designed to prevent pressure increases in closed systems. A rolling diaphragm provides a variable volume, that when properly sized, maintains oil housing pressure at or near zero PSI. The reduced pressure will extend seal life and help prevent leakage. Expansion chambers also protect the integrity of closed systems by preventing the exchange of air from the chamber to the surrounding atmosphere. A choice of thread sizes and capacities offers flexibility to the user.


  • Made from corrosion resistant stainless steel
  • Controlled housing pressure extends seal life
  • Prevents contamination ingression to help lubricants stay cleaner for longer life and improved performance
  • Full 25 cubic inch air expansion capability
  • Maintenance free operation

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Instruction Sheets



Model No.DescriptionConnection (NPT)CapacityDim A (in)
31815Expansion Chamber3/825 cu in7/8
31816Expansion Chamber1/225 cu in1
31817Expansion Chamber3/425 cu in1-1/4
31835Expansion Chamber with Vent Hole1/225 cu in1
Body Stainless Steel
Diaphragm Viton®
Max. Operating Temp. 350ºF
Expansion Capacity 25 cubic inches

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