Description

The Tridak model 775 is a compact, air actuated, normally closed, spool type shut-off valve that provides precise control over both the rate (adjustable flow gives absolute control over the amount of material deposited during a specific period of time) of flow while operating, and the amount of suck-back (Control over the amount of suck-back is mandatory to achieve consistent string less cut-off of tacky materials and to eliminate air entrapment, and also prevents a droplet from remaining on a dispense nozzle when used with thin materials, both of which drastically effect accuracy and repeatability) when closing. Both controls are conveniently located on the end opposite the material outlet and are lockable to prevent drift or tampering.

Operation
The valve is by a 50-150 PSI air signal from a user supplied 3-way normally closed air valve. The signal causes the internal spool to shift to its open (flowing) position a precise amount determined by the adjustable flow control setting.

When the operation air signal is removed, the material flow is instantly shut-off, then the end of the spool continues to travel for an adjustable distance. This adjustable travel creates a precisely controlled suck-back action. This suck-back can be set in a manner that breaks the tail from stringy materials or remove a tiny droplet that would normally remain at the tip of the nozzle with thin materials.

Available Models:
775V - Valve w/ Snuff Back
775SS - All Stainless Steel Construction
775SSW - Stainless Steel Wetted Areas
775H - Heated w/ Thermo Couple & Temp Control