CPI Compression

Unloaders and Actuators

We offer both diaphragm- and piston-style actuators for use with finger and plug unloader assemblies. Our actuators come with new valve upgrades for replacing leaking and worn out actuators, or for removing manual hand wheel style unloaders for automation. In situations where membrane failures occur or there is insufficient stroke, our diaphragm actuators can be used to replace existing membrane actuators.


  • Available in air-to-load or air-to-unload
  • Rolled diaphragm design eliminates problems caused by reconditioning and membrane failure
  • Highly visible position indicators
  • Sealing with O-rings, lip seals and chevron packing
  • Vent connection for collecting fugitive emissions
  • Special materials available for corrosive applications
  • Custom designed for each application
  • Design features prevent gas emissions
  • Most old-style unloading systems can be upgraded with CPI Unloader Actuators
  • Depending on the application, a single plug unloader actuator per cylinder end can replace existing multiple finger unloader actuators
  • Used for valve port unloading with a Compressor Products International plug valve or for volume pocket unloading
  • Solid plug and balanced plug styles are available
  • Meets API 618 standards


  • Rolled diaphragm:
    • .59 in/15 mm stroke available
    • spindle length adjustable by .20 in/5 mm
  • Sealing pressures up to pressures of 3,625 psi/250 bar



Plug Style Unloader_LTR_Howden.pdf