Graco Dispensit 792-20 [4/14] Description of operation

DESCRIPTION OF OPERATION

1. The normal ready state of the system is as follows:

The syringe or remote reservoir contains the dispensable material.

The system has been purged, filling the material hose and needle with material.

The Pinch-off Piston (11) is not pressurized, but is held back by the Springs (10) closing the

Material Hose (16) and holding back the dispensable material.

2. The dispense cycle begins when the controller is activated.

3. The Pinch-off Piston (11) moves forward to release the Material Hose (16) allowing material to flow.

4. To complete the dispense cycle, the Pinch-off Piston (11) is pushed back by the Springs (10), sealing

the Material Hose (16) to prevent material drip. The system is again in the normal ready state.

SETUP PROCEDURES

MOUNTING DISPENSE VALVE

For optimum operation, the Model 792-20 Dispense Valve must be mounted on a 1/2 inch (12.7 mm)

support rod post or frame. When mounting, affix the valve firmly in place by tightening the socket head

cap screw with a 5/32 inch Allen wrench. Depending on the application, the valve may be tilted to a

maximum of 60

from the vertical.

AIR CONTROLLER

Operation of the Model 792-20 Dispense Valve requires a controller that can provide the following:

A minimum of 0.5 SCFM (2.3 cm

) of dry, unlubricated air at a minimum pressure of 4.8 bar (70 psi)

and a maximum of 6.9 bar (100 psi).

Time delay capability to allow the valve to cycle.

Independent air pressure regulators for material reservoir and valve operation.

“Purge capability” which is the ability for the operator to pass or not pass air to the Pinch-off Piston

(11) on the dispense valve.

For semiautomatic or automatic applications, a foot switch or other control to cycle the valve.

Connection for .16” ID x .25” OD(6.35mm) pressure tubing for use between the dispense valve and

controller.

Connection for .16” ID x .25” OD(6.35mm) pressure tubing for use between the controller and syringe.

NOTE: The material supply must be regulated to a maximum of 60 psi (4.1 bar).