A step by step manual on how the Clouston hot press compression controller works, and its benefits.



  1. The press operator pushes the Start/closed button.
  2. As the press is closing, the actuator arm that Clouston Hydraulics has attached to your bottom platen comes in contact with and lifts the feed back bar which slides through the valve/encoder enclosure.
  3. The feed back bar will now follow the movement of 
    the bottom platen.
  4. As the press continues to close, the Clouston HMI 
    (Human Machine Interface) located at the operators 
    station is displaying the increasing ram pressure.
  5. The Clouston PLC is just monitoring and displaying at this point.

  1. The press comes to full pressure. At that instant, the timer on the Clouston Controller comes on and the ram movement indicator starts to monitor compression of the plywood panels in the press.
  2. The Clouston Controller is in "monitor only" mode at this time. The "ram movement" indicator is showing movement of the feedback bar which is following the movement of the bottom platen.
  3. The timer is counting down the seconds that the operator has programmed into it.
    Note: The time shown on the "full pressure" timer is the amount of time you are compressing the plywood in the Hot Press, it is not the same as the cycle time.

Note: The "FULL PRESSURE TIME: on the Clouston is the amount of time you are compressing the plywood at full hydraulic pressure. It is not the same as the amount of time panels will need to be in the press or the "cycle time".


  1. When the timer on the Clouston has timed out, the controller energizes a blocking valve between the pressure pump and the ram cylinders. The Clouston 
    Controller has now stopped compression of the plywood panels and is going to maintain platen position.
  2. As the wood cells in the panels yield to the heat of the platens, It will require less pressure to maintain position. Therefore, the Clouston must port oil out of the rams and back to tank.

    Note: The controller also has a 
    high pressure line from 
    the pump so oil can be 
    added to the ram if 
  3. Throughout the remaining cycle time, ram pressure will decrease and platen position will not change. You will not over compress the panels and thus maximum panel thickness is maintained.
  4. When the press timer has timed out the Clouston shuts off and the press opens.

Through testing you can maximize panel thickness and maintain your current glue bond quality.  The majority of the mills using the CLOUSTON HOT PRESS COMPRESSION CONTROL have gained enough in panel thickness to allow them to reduce their veneer peel by .002�.  That is approximately 2.43 cubic inches of wood per linear foot of veneer peeled.