Vacuum Pressure Impregnation (VPI) Systems

VPI technology can be used in a wide range of applications from insulating electrical coil windings to sealing porous metal castings. It normally produces better product in less time and lower cost than other available procedures.

Our VPI systems can be configured in a variety of ways, depending on the size and form of the product to be impregnated, the type of impregnant used and other production factors.

Special features of a WSF VPI system include our unique RAPIDOOR ® a breech-lock enclosure that opens and closes in seconds, and an Impregnator False Bottom that reduces the overall required volume of costly resins.

Control System Package Options

WSFdesigns and manufactures VPI systems - including the vessels - in our own plant. System packages include all necessary valves, gauges, instruments and piping. Control options range from completely automated, micro-processor based controls to manual selector switch operated systems. Our engineering staff has designed control systems using most major PLC and Human Machine Interface brands including: Allen-Bradley, Mitsubishi, Omron, Modicon, & GE.

Our complete design and manufacturing capabilities offer several advantages:

  • Modifications or custom-assembly to meet specific needs
  • Single-source responsibility for the entire installation
  • Quality and cost control over manufacturing and assembly
  • Eliminates delays, re-work, costly mistakes arising from the use of several subcontractors

Typical VPI Cycle

  • Load the work piece into the impregnator.
  • Close and lock the impregnator door.
  • Pull vacuum for a specified period of time to remove air and moisture or until desired vacuum is reached.
  • Open transfer valve and allow resin to flow from storage tank into the impregnator.
  • Close transfer valve and hold impregnator under vacuum.
  • Break vacuum with inert gas.
  • Pressurize the impregnator and hold to achieve maximum impregnation for positive penetration of impregnant into voids.
  • Vent the impregnator.
  • Open impregnator door and remove work piece.
VPI Systems for Electric Motor Repair Shops

WSF cycle times are much faster than the "dip and bake" method, thus reducing operating costs while increasing capacity. Our VPI systems are more affordable because they are packaged to fit the application accelerating investment payback.

Other advantages include:
  • Deeper resin penetration
  • Void-free insulation that minimizes corona, improves heat transfer and provides greater bond strength
  • Protects against moisture, dirt and corrosive chemicals
  • Results in longer life for the motor rewinds, boosting the shop's reputation for quality work
VPI Systems for Manufacturing

WSF VPI systems are used by the electrical industry in the processing of coil windings, transformer components, power cables, fiberglass laminations, cores, paper products and other items. Carbon product manufacturers impregnate pitch or chemical solutions into electric furnace electrodes, piping and tubing for heat exchangers, nuclear power plants and pump components. Metallurgical industries impregnate porous castings with sealants of several types, providing significant savings for producers and users of castings.

Wood products are impregnated with various substances to protect against rot, termites and other insects, fire, weather effects and heavy use.