Graco 332097A User Manual

Instructions

332097A

EN

Dispense Valve

Important Safety Instructions

Read all warnings and instructions in this manual.
Save these instructions.

Dispensit 902-20

2

TABLE OF CONTENTS

GENERAL INFORMATION .................................................................................... page 3

DESCRIPTION ....................................................................................................... page 3

SAFETY INFORMATION ....................................................................................... page 3

DESCRIPTION OF OPERATION ........................................................................... page 4

POSITIVE DISPLACEMENT SEQUENTIAL FUNCTION ...................................... page 4

SET-UP PROCEDURE .......................................................................................... page 5

MOUNTING DISPENSE VALVE ............................................................................ page 5

AIR CONTROLLER ................................................................................................ page 5

DRY SYSTEM CHECKOUT ................................................................................... page 6

MATERIAL LOADING ............................................................................................ page 6

WET SYSTEM CHECKOUT ................................................................................... page 7

CLEANUP ............................................................................................................... page 7

DISPENSING NEEDLE .......................................................................................... page 7

DISPENSE TUBE ................................................................................................... page 7

VALVE DISASSEMBLY .......................................................................................... page 8

CLEANING ............................................................................................................. page 8

VALVE REASSEMBLY ........................................................................................... page 9

TROUBLESHOOTING ......................................................................................... page 10

WARRANTY AND LIABILITY ............................................................................... page 11

3

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. It comes complete with the following:

• Model 902-20 Dispense Valve

• Two 3 foot (1 m) sections of Pneumatic Air Line

• One package of Replacement Dispense Tubes (type as ordered)

• Micrometer-Faceplate Assembly mounted on Dispense Valve

• Syringe (size as ordered)

• Optional Syringe Clamp (comes with syringe option)

• Receiver Cap with air line (comes with syringe option)

• Operating Manual

SAFETY INFORMATION

This product should be used only by employees who have been given appropriate training and safety
warnings as set forth in this manual. Read completely before operating.

Warning: Do not exceed 100 psi (690 kPa) pressure on the operating system or 60 psi (414 kPa)
pressure on the syringe reservoir. Higher pressures are not required and may cause a serious hazard.

Toxicity and flammability hazards depend upon the product being dispensed by this unit, and the user
should take appropriate safety precautions as indicated on the MSDS of the product.

Always wear safety glasses.

4

FILL

DISPENSE
DELAY

DISPENSE

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. The Bottom Pinch-Off Piston is not
pressurized (forward) but is held back by the springs, closing the Dispense Tube and holding back the
dispensable material. (See "Fill" on drawing below.) The Top Pinch-Off and Dispense Pistons are not
pressurized (back).

The dispense cycle begins when the controller is activated.

The Top Pinch-Off Piston first moves forward to stop material supply and the Bottom Pinch-Off Piston
moves forward to release the Dispense Tube. (See "Dispense Delay" on Sequential Function drawing.)

The Dispense Piston then moves forward until stopped by the Micrometer Stroke Adjust. This
squeezes a precise amount of material out of the Dispense Tube. (See "Dispense" on Sequential
Function drawing.)

When the dispense cycle is complete, the spring pushes the Bottom Pinch-Off Piston back, sealing the
Dispense Tube to prevent material drip. Immediately after, the Dispense Piston and Top Pinch-Off
Piston withdraw allowing the material from the pressurized reservoir to refill the Dispense Tube. The
system is again, in the normal "ready" state.