Valves described above have one thing in common is that they are not designed to dispense high viscosity fluid in high volume applications. To fill this gap, OK International offers the spool valve series. High viscosity fluid, up to 3 million cps is dispensable through a heavy duty spool valve version. The valve uses an air-actuated piston to opens and closes the fluid’s path. However, contrary to the needle valve, the air pressure signal drives the piston down to open the fluid path. When the dispense cycle is done, the internal compression spring lift the piston up to keep the valve in the closed position.
The pull-back action of the piston in the closing cycle creates a natural “suck-back” action. This feature is very effective for preventing drips when dispensing high viscosity fluid such as silicones, greases and sealants. Most use application of this valve is to dispense sealant for form-in-place gasket application. Other commonly applications that well suited are: dispensing grease for automotive application, filling material into syringes or cartridges for the material packaging industry.