Hunkar Valves

Hunkar Laboratories offers a wide variety of valves for use in the blow molding process. Below you will find useful information on the Hydro-Jet 2 valve



Hunkar Laboratories presents the latest innovation in blow molding  Servo Valve technology.
The HYDRO-JET 2 dirt tolerant valve is so stable it now requires NO Null Adjustment. HYDRO-JET 2 has a null stability of 5% of rated current throughout its entire useful life, so it does not require any null adjustment. Additionally, the first stage jet-pipe within the unit will pass 130 micron particles without failure.

The HYDRO-JET 2 has a resolution of ¼% of rated current, delivering substantially improved precision
compared to other jet valves used in the industry today. The efficient four air gap torque motor drives the jet-pipe hydraulic preamplifier and controls the second stage spool. HYDRO-JET 2 has been developed and constructed to withstand the most demanding plastics blow molding applications.

Jet-Pipe Valve


  • Fixed Null Accuracy
  • Highly Dirt Tolerant
  • High tolerance to contamination.
  • The first stage jet-pipe will pass 130 micron particles without failure.
  • Protected by a proprietary 90 micron absolute strainer.
  • The second stage is precisely controlled by a high gain frictionless force feedback servo system.
  • Dry torque motor in a sealed housing
  • Compact smaller design profile


  • Continuous operation despite mild hydraulic oil system contamination.
  • Zero maintenance and smooth operation.
  • Easy replacement on old machines.
  • Fits a wide range of machines.
  • Economical replacement for most servo valve brands.
  • Rapid, simple bolt on installation.
  • Durable construction for long service life.
  • Accurate, smooth and repeatable performance.

Performance Specifications

  • Rated Flow: 5 GPM ±5% *
  • Hysteresis: Normally less than 3% of rated current
  • Resolution: ¼% of rated current
  • Linearity: 5% of rated current
  • Frequency Response: -3dB as 60 Hz
  • Pressure Gain: 25% of System Pressure/1% of rated current
  • Null Shift vs. Supply Pressure: 2%/1000 PSI
  • Null Shift vs. Oil Temperature: 2%/100° F
  • Total Internal Leakage: Less than 0.35 GPM at 1000 PSI

System Requirements

  • Operating Fluid: High Grade Petroleum oil, 100 to 150 SSU at 100° F.
  • Filtration: 75 micron absolute (or better) pressure line filtration, non by-passable with 3000 PSI element.
  • Operating Supply Pressure: 1000 to 3000 PSI
  • Operating Temperature: 40 to 250° F.
  • Rated Electrical Input: 70 MA into 80 W (5.6V)

Recommended Accessories

  • Manifold P/N 86033
  • Flushing Block P/N 86041 * Rated Flow: 16 GPM also available.