Polyurethane Process Industries, LLC

Hydraulic System

Where the customer comes first

Replace or upgrade your system with
mix head hydraulic components from PPI

Polyurethane foam processing demands much from a mix head hydraulic system. Pressure spikes are typical. Hydraulic oils can degrade or become dirty quickly.

Premature failure of hydraulic pumps and manifold blocks, recurring oil leaks, and frequent replacement of valves and other components are common signs of pressure spikes and a poorly designed mix head hydraulic system.

We offer mix head hydraulic components that represent the best in quality, performance and value for processors of polyurethane foam:

Image - Hydraulic system parts shown are hydraulic unit, mix head valve manifold, poppet valve, directional valve, pressure gauge

Related Links:

» Hydraulic Pumps

» PU System Modification

Mix Head Hydraulic Units

PPI hydraulic units are designed specifically for PU mix head piston control, long life, and low maintenance. We start by making sure pressure spikes are minimized, and we select components designed for a dirty production environment.


  • 20 gallon "L" shaped reservoir for easy access to all components.
  • Externally mounted pump, suction, and return filters for faster maintenance.
  • Rugged 4.5 gpm internal gear pump with a continuous/intermittent pressure rating of 4,750/5000 psi.
  • Fast-acting relief valve to minimize pressure spikes .
  • High flow unload valve
  • 2.5 gallon accumulator with manual bleed down .
  • Programmable pressure switch with digital readout to load and unload the pump .
  • Water/oil heat exchanger with modulating valve .
  • Reservoir level and return filter switches (optional).

Contact us for details and pricing.

Image: Mixhead hydraulic unit

Mix Head Valve Assembly

Our long-life valve assemblies are designed to provide maximum control of oil flow to mix head pistons as they open and close during each shot. Flow control is important to adjust piston speed, reduce heat buildup, and increase mixhead life.

PPI valve assembly features:

  • Steel manifold block. We do not use aluminum blocks because they cannot withstand constant pressure changes.
  • Two (2) high flow directional valves with lighted Din plugs (24 or 110 volt) to control pour and cleanout piston movement
  • Two (2) flow control valves to control the flow of oil while opening and closing both valves

Contact us for details and pricing.

Image: Mixhead hydraulic valve assembly with manifold block

Related Links:

» Chemical Valves & Valve Assemblies
» Mix Head Parts

Hydraulic Valves

We supply a wide range of valves for mix head hydraulic systems:

  • Directional Valves extend and retract mix head pistons during operation. These solenoid-operated, directional spool valves have an operating pressure rating of 5,100 psi (350 bar). Optional orifice inserts prevent flows exceeding the valve rating.
  • Flow Control Valves increase the life of mix heads and seals by reducing the flow of hydraulic oil to mix head pistons. Reduced flow decreases piston speed and the amount of heat generated during operation. We offer sandwich and cartridge flow control valves suitable for most mix head hydraulic systems.
  • Poppet Valves help reduce heat build-up when the hydraulic system has reached operating pressure and is in idle or standby mode. These two-way, hydraulic cartridge valves are pilot operated by solenoid and unload the pump by directing flow back to the tank. The valves screw into place and are wired normally open. Construction is aluminum or heavy-duty steel.

Contact us for details and pricing.

Image - Hydraulic directional valve
Image - Hydraulic flow control valve
Image - Hydraulic poppet valve

Hydraulic Filters

Using the correct filter for your equipment and application can extend the life of hydraulic fluid and system components. We supply filter elements for hydraulic pumps, suction lines and return lines.

We also offer an Offline Hydraulic Filter for reservoir volumes up to 1000 gallons. The offline filter can be supplied with motor and pump for easy offline installation, or can be used by itself. A tank connection kit is available for use with bypass and ventilation filters.

Offline Filter Features:

Image: offline hydraulic filter
Image: hydraulic filter elements

Related Links:

  • Flow rates of 1.3 to 4.9 GPM
  • Operating pressure 45 psi (max)
  • Fluid temperature 32º to 175º F
  • Clogging indicator
  • 2 or 20 micron elements
  • Standard NBR seals
» Chemical Filters

Contact us for details and pricing.

Pressure Switches, Transducers and Gauges

We offer a wide variety of analog and digital pressure gauges, including Hydac electronic pressure switches that combine the functionality of a switch, transducer and gauge in one compact unit. We also supply individual pressure switches, transducers and analog and digital gauges.


Image - digital pressure gauges, analog pressure gages
  • Pressure range: 0-9000 psi
  • Overload: 150 or 200 % FS
  • Analog or digital outputs
  • Dial or LED displays
  • Display psi, bar or mpa
  • Stainless steel construction

Contact us for details and pricing.