Instructions 332097A Dispensit 902-20 Dispense Valve Important Safety Instructions Read all warnings and instructions in this manual. Save these instructions.
TABLE OF CONTENTS GENERAL INFORMATION .................................................................................... page 3 DESCRIPTION ....................................................................................................... page 3 SAFETY INFORMATION ....................................................................................... page 3 DESCRIPTION OF OPERATION ...........................................................................
GENERAL INFORMATION DESCRIPTION The Model 902-20 Positive Displacement Pinch Action Dispense Valve with micrometer adjustment is designed for applications that require dot-to-dot volumetric consistency. It has material viscosity dispensing capability from water type material to high viscosity epoxies and metal filled pastes. This valve also has a fail-safe design to prevent material dumping in ease of power failure. All wetted parts are disposable for easy maintenance and cleaning.
DESCRIPTION OF OPERATION POSITIVE DISPLACEMENT SEQUENTIAL FUNCTION The normal "ready" state of the system is as follows: The dispense valve may operate with a (remote) reservoir or with a syringe (mounted with the valve). In the ready state, the syringe or reservoir contains dispensable material. The system has been purged, filling the Dispense Tube and needle with material.
SET-UP PROCEDURE MOUNTING DISPENSE VALVE For optimum operation, the Dispense Valve must be mounted on a 1/2 inch (12.7 mm) support rod post or frame. When mounting, firmly affix the valve in place by tightening the Black Socket Head Cap Screw with a 5/32 inch Allen Wrench. The valve may be tilted to a maximum of ±60° from the vertical depending on the application. AIR CONTROLLER Operation of the 902-20 Dispense Valve requires a controller that can provide the following: • A minimum of 0.5 SCFM (2.
DRY SYSTEM CHECKOUT This is an initial checkout to determine if the setup has been properly completed. The dry checkout is conducted without any material in the system. Attach the pressure lines from the Dispensing Valve to the air outlets on the air supply controller. Turn on the electric and air supply. Set the air pressure to 70 psi (483 kPa) on the system pressure gauge. In the normal rest position, the spring holds the Lower Pitch-Off Piston back, sealing the Dispense Tube.
WARNING: Do not apply either operating or reservoir air pressure to the product unless all screws are in place and properly tightened, and the receiver cap and/or the reservoir are properly in place and tightened. All air connections should be fastened securely. Attach the air line to the regulator and set the air pressure control to 15 psi (103 kPa) or to the setting required for the application.
• Frequently the new tube comes cut at an angle so the tip is tapered; the allows you to pull it through luer lock or other fittings which hold the ends. After the tubing is pulled through, cut of the excess smoothly and squarely. • Others may use the material delivery tube - pull this tube farther through luer the pinched portion can be cut off. When the tube becomes too short it will be necessary to replace it. 5. Gently tighten the upper and lower screw knobs after the new tube and needle are replaced.
VALVE REASSEMBLY Note: Use the new parts that are in your seal kit where possible. Note: Use caution as you install the new U-seals into the sleeve assembly so you don't pinch or tear them. Do this by making sure they are lubricated, and by tucking the lips of the U-seal inward before uniformly pushing it down into the valve sleeve. Lightly lubricate parts to facilitate reassembly.
TROUBLESHOOTING If operating difficulties occur, review the symptoms below. With each problem there are one or more possible causes which should be investigated to resolve the situation. Nothing HAPPENS - If absolutely nothing happens when trying to cycle the Dispense Valve, check the electric/pneumatic power. Check the foot-switch or cycle start switch to be sure it is plugged in, VALVE CYCLES, NOTHING DISPENSED - First, try to purge the unit; this should fix most situations.
Graco warrants all equipment referenced in this document which is manufactured by Graco and bearing its name to be free from defects in material and workmanship on the date of sale to the original purchaser for use. With the exception of any special, extended, or limited warranty published by Graco, Graco will, for a period of twelve months from the date of sale, repair or replace any part of the equipment determined by Graco to be defective.
