Graco 332096A User's Manual
Contents
1. 12 General Guidelines for O rings and U cup Seals 13 L AI Id rz o 14 2 GENERAL INFORMATION The Model 792 20 Dispense Valve is designed for applications that require ON OFF dispensing of beads and or dots It has dispensing capability for material viscosities ranging from water type material to high viscosity epoxies and metal filled pastes This valve also has a fail safe design to prevent material dump ing in case of a power failure All wetted parts are disposable for easy maintenance and cleaning The 792 20 ships complete with the following Model 792 20 Dispense Valve One 3 foot 9 m section of pneumatic air line One material hose type as ordered Seal Kit Operating and Maintenance Manual SAFETY INFORMATION This product should be used only by employees who have been given appropriate training and safety warnings as forth in this manual Read completely before operating 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 ILLUSTRATION REFERENCES Throughout this manual you will find references by illustration item number to the illustrations in the manual The references are indicated by parentheses around a number such as 7 Illustrations represent typical valve configuratio2. Instructions GRACO 332096 Dispense Valve e Important Safety Instructions Read all warnings and instructions in this manual Save these instructions PROVEN QUALITY LEADING TECHNOLOGY MODEL 792 20 DISPENSE VALVE OPERATING amp MAINTENANCE MANUAL General Information 3 Safety Information roS 3 Illustration References 3 General Accessories 1 eoecxecoriiii o oor a o Ea cle RO rS 3 Description Of Operation UU UI 4 Setup 4 DISPENSE EET T 4 nido ERE 4 Operating Procedures 5 Diy System CHECKOUT ERR UU UT UT 5 el MERE 9 Remote Mounted Material Supply 5 Wet System ClIGeKOLIE rendu ERN 6 Periodic eene nnnm nnn nnnm nnns nenne nnn 6 Material Hose Renewal 6 Material Hose 7 ISAS SE _____ __ _ 6 6 6_6 8 Model 792 20 General 9 PRS SSN 10 11 Model 792 20 Recommended Spare Parts
3. emp i d lij LIN 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 e Aminimum 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 e Time delay capability to allow the valve to cycle Independent air pressure regulators for material reservoir and valve operation e 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 e Connection for 16 ID x 25 OD 6 35mm pressure tubing for use between the dispense valve and controller e Connection for 16 ID x 25 OD 6 35mm pressure tubing for use between the controller and syringe GRACO OPERATING PROCEDURES DRY SYSTEM CHECKOUT This is an initial checkout to determine if the setup has been properly completed Conduct the dry system checkout without any material in the system 1 Attach the colo
4. HOSE ADAPTER option teaser GRACO PERIODIC MAINTENANCE ASSEMBLY Refer to the illustration above and to the drawings in the back of the manual for your exact model and others The Springs 10 can become Aying objects they escape your contol sre ey ar at and By ui e mar fors uo pushing hem nb l Install the U cup Seal 7 on the Pinch off Piston Insert the Springs T into the Pinch off Piston sp 3 Setthe Pinch off Piston assembly on top of the Cylinder Base Assembly 6 Use a blunt tool to carefully tuck the U cup Seal 7 in while easing the piston into the Cylinder Base Assembly 6 See drawings for piston orientation 4 Compress the Springs 10 with small screwdriver or other tool to assist in placing the Backplate 1 in position Be sure the Springs 10 are centered under the Backplate 1 5 Insert two of the Tie Rods 4 and install two Screws 2 and tighten them to tie the Backplate 1 down 6 Place the Faceplate 15 onto the Backplate 1 See drawing for orientation Slide the two Spacers 21 into position and install two Screws 3 through the faceplate and spacers and tighten them 7 Slide the Top Tube Adapter 12 hexagon end up onto the new Material Hose 16 8 Slide Bottom Tube Adapter 17 onto the new Material Hose 16 until the hose is flush with the end of the adapter 9 Depending on the valve configuration insert the steel end of the Hos
5. Tube Adapter 17 Remove the Bottom Tube Adapter 17 and Top Tube Adapter 12 from the Material Hose 16 Discard the old material hose Remove the Faceplate 15 by loosening and removing two Screws 3 holding it in place 11 Loosen and remove two Screws 2 holding the Backplate 1 in place The Backplate 1 the Pinch off Piston 11 and its Springs 10 will come loose from the rest of the valve At this time all four Tie Rods 4 will be free and may be set aside Disassemble Backplate 1 from Pinch off Piston 11 12 Remove the U cup Seal 7 from the Pinch off Piston 11 GRACO MODEL 792 20 GENERAL ILLUSTRATION pir n SF L pr p B gne PT pe Emm Sea ae TA ANN 9 G g 9 m 1 A frr i ma cT i RA SU y 04 E 2 2 ______ 8 2 SREW 832x1 ___ 4 MERO 8 6 CYLINDER BASE ASSEMBLY 7 1 JUQUPSEAL 8 4 SREWf amp 32xi eI INLET 2 SPRN amp M 1 ror Tue ADAPTERS L8 2 a O 1 BOTTOM TUBE ADAPTER NEEDLE ASSEMBLY option
6. i E Fa por E T ii a rrr aaa Ji 6 GRACO PERIODIC MAINTENANCE MATERIAL HOSE REPLACEMENT If material hose renewal is not feasible then follow these steps to replace the material hose 1 Depressurize the material reservoir and remove disconnect it 2 Pressurize the Pinch off Piston 11 This is the purge mode The Material Hose 16 will now be completely free of compression 3 Loosen the upper and lower Knobs 13 enough to allow the Material Hose 16 Top Tube Adapter 12 and Bottom Tube Adapter 17 to pass out the side of the valve 4 f your valve has a Hose Adapter 19 disconnect downstream fittings as required so that the Hose Adapter can be turned freely o Depending on the valve configuration disconnect either the Needle Assembly 18 or Hose Adapter 19 from the Bottom Tube Adapter 17 6 Remove the Bottom Tube Adapter 17 and Top Tube Adapter 12 from the Material Hose 16 Discard the old material hose 7 Slide the Top Tube Adapter 12 hexagon end up onto the new Material Hose 16 8 Slide Bottom Tube Adapter 17 onto the new Material Hose 16 until the hose is flush with the end of the adapter 9 Depending on the valve configuration insert the steel end of the Hose Adapter 19 or Needle Assembly 18 into the end of the Material Hose 16 and tighten onto the Bottom Tube Adapter 17 10 Slide the Top Tube Adapter Material Hose Bottom Tu
7. RYTOX 203GPL ASSEMBLY LUBRICANT 84 0200 K3 11 8218 HP 170 0 1 4NPTMx35 4102024 __ 5218 188 0 14 3 56 A1020142 __ 0000 8218 PE 188 0 1 8 NPTMx3 5 A10200141 o 5218 250 0 1 4 3 5 1020218 The quantity may vary for your application 12 GRACO GENERAL GUIDELINES FOR O RINGS U CUP SEALS Sizes and materials of construction for O rings and U cup seals are selected by Graco Liquid Control based on compatibility with the chemicals to which they will be exposed Solvents that may remove residual chemicals often have negative effects on the mechanical properties of O rings and seals O Ring Guidelines Always replace an O ring with the identical one in size durometer hardness type and material of construction Always be alert to the location and size of each O ring as many look alike and be careful not to mix them Often similar sizes may be used in various locations on the equipment and if replaced incorrectly the equipment may not function properly Refer to the Machine Operation and Service Manual for the correct part number of all O rings used throughout the equipment and replace them with factory approved parts only Re use of O rings is not recommended Only re use O rings as a last resort If you must re use them be sure that they are clean have no cuts or flat spots and contain NO foreign material Also b
8. aintenance sections of this manual IRREGULAR VOLUME DISPENSED Irregular dispensing can usually be attributed to faulty material The material must be a smooth homogeneous mixture without any air trapped in it A second cause could possibly be that the material is not filling the material hose tube fully and in time Check the reservoir pressure it may be too low for the type of material being dispensed and or the cycle time may be set too fast Cycle time is a function of the air supply controller To adjust follow the directions found in the controller operating manual REDUCED VOLUMES DISPENSED Check to see if material hose requires replacement or whether needle is partially clogged Refer to Periodic Maintenance Section TUBING LIFE VERY SHORT Incorrect material hose tube wall thickness too large VALVE DRIPS Material hose needs replacing wrong material hose used wall thickness too small SLOW OR SLUGGISH CYCLE TIME This may be due to inadequate lubrication of the piston walls Remove the pinch off piston Apply a very thin film of Krytox lubricant part number 84 0200 K3 11 to the outside diameter surfaces of the pistons and the U seal and reassemble This will restore smooth and consistent operation 11 GRACO MODEL 792 20 RECOMMENDED SPARE PARTS Note These parts are routine supply items or wear parts not covered by warranty for normal wear SEAL 792 20 see assembly drawing number K
9. be Adapter Assembly 12 16 amp 17 through the side of the valve 11 Gently tighten the upper and lower Knobs 13 12 Connect any downstream fittings that you disconnected from the Hose Adapter 19 13 Connect the material reservoir and pressurize it 14 Perform the Wet System Checkout and return to operation am wi ld zx m AN MUN mi Ji EN m c d CNN 1 E Hm ae GRACO PERIODIC MAINTENANCE DISASSEMBLY Refer to the illustration below and to the drawings in the back of the manual for your exact model and others The Springs can become fying objects H they escape your ontok 709 OO NO oF oD po Turn off the material supply pressure to the valve and disconnect the material supply Turn off the air supply pressure to the valve and disconnect the air supply line from the valve controller Remove the dispense valve from its mounting Loosen the upper and lower Knobs 13 enough to allow the Material Hose 16 Top Tube Adapter 12 and Bottom Tube Adapter 17 to pass out the side of the valve If your valve has a Hose Adapter 19 disconnect downstream fittings as required so that the Hose Adapter can be turned freely Depending on the valve configuration disconnect either the Needle Assembly 18 or Hose Adapter 19 from the Bottom
10. e Adapter 19 or Needle Assembly 18 into the end of the Material Hose 16 and tighten onto the Bottom Tube Adapter 17 10 Slide the Top Tube Adapter Material Hose Bottom Tube Adapter Assembly 12 16 amp 17 through the side of the valve 11 Gently tighten the upper and lower Knobs 13 12 Mount the valve to its point of use 13 Connect any downstream fittings that you disconnected from the Hose Adapter 19 14 Connect the material reservoir and pressurize it 15 Connect the air supply line to the valve controller Perform the Dry System Checkout Material Loading and Wet System Checkout The valve is ready to be put back in service 10 GRACO TROUBLESHOOTING If operating difficulties are encountered review the symptoms below With each problem there are one or more possible causes that should be investigated to resolve the situation NOTHING HAPPENS If absolutely nothing happens when trying to cycle the Dispense Valve check the electric and pneumatic power Check all control connections for proper installation VALVE CYCLES NOTHING DISPENSED First try to purge the unit this should fix most situations If nothing is dispensed check to see that there is enough pressure to the material reservoir Perhaps the reservoir material hose needle path is clogged examine and clear or replace as necessary Consider whether the material could have set up in the system Refer to the Wet System Checkout and Periodic M
11. e is difficult to predict due to its dependence on the cycles speed downtime and material dispensed A common sign of a worn material hose is a reduction in shot volume Inspect the material hose periodically and renew or replace as necessary Depending on the application layout it may be possible to renew the pinch area of the material hose by pulling it through the valve and trimming off the worn area 1 Depressurize the material reservoir and remove disconnect it 2 Pressurize the Pinch off Piston 11 This is the purge mode The Material Hose 16 will now be completely free of compression 3 If your valve has a Hose Adapter 19 disconnect downstream fittings as required so that the Hose Adapter can be turned freely 4 Remove the Hose Adapter 19 or Needle Assembly 18 from the Bottom Tube Adapter 17 5 Pull the Material Hose 16 down through the valve to expose the worn pinch area on the Material Hose Cut the Material Hose squarely above the worn pinch area and flush with the end of the the Bottom Tube Adapter 17 6 Insert the steel end of the Hose Adapter 19 or Needle Assembly 18 into the end of the Material Hose 16 and tighten onto the Bottom Tube Adapter 17 Check all connections If your valve has a Hose Adapter 19 connect downstream fittings to it Connect the material reservoir and pressurize it Perform the Wet System Checkout and return to operation ON 1 p mmm umm
12. e sure not to soak them in solvent for extended periods as this can cause deterioration of the O ring Always replace O rings that are cut nicked or distorted in shape or cross section Always apply a very thin film of Krytox 203GPL lubricant item 84 0200 K3 11 to the entire surface of the o ring before installation Avoid excessive lubrication If installing O rings over threads on a shaft or across sharp edges roll or push the O ring carefully into place being careful to avoid cutting or nicking it Avoid stretching the O ring too much as it may not return to the proper size Do not use any sharp tools or objects to install O rings U cup Seal Guidelines Always replace a U cup seal with the identical one in size durometer hardness type and material of construction Always be alert to the location and size of each U cup seal as many look alike and be careful not to mix them Often similar sizes may be used in various locations on the equipment and if replaced incorrectly the equipment may not function properly Refer to the Machine Operation and Service Manual for the correct part number of all U cups used throughout the equipment and replace them with factory approved parts only Always apply a very thin film of Krytox 203GPL lubricant item 84 0200 K3 11 to the inner and outer lips of the seal before installation Re use of U cup seals is not recommended Only re use U cups as a last resort If you must re use them be
13. ns The drawings for your exact model are inserted at the back of the manual and include the part numbers for ordering replacement parts GENERAL ACCESSORIES Graco Liquid Control offers a full line of standard and custom accessories for your dispensing needs including Valve Controllers Syringe Feed Systems Cartridge Retainers and Pressure Reservoirs Transfer Pump Feed Systems for 1 5 and 55 gallon containers Mounting Bases and Brackets Consult your Dispensit dealer or the factory for details GRACO DESCRIPTION OF OPERATION 1 The normal ready state of the system is as follows he syringe or remote reservoir contains the dispensable material e The system has been purged filling the material hose and needle with material he 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 The dispense cycle begins when the controller is activated The Pinch off Piston 11 moves forward to release the Material Hose 16 allowing material to flow 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 DIS d dE hh m E ARRA e ir REX RA t 7 DEN
14. nstalled operated and maintained in accordance with Graco s written recommendations This warranty does not cover and Graco shall not be liable for general wear and tear or any malfunction damage or wear caused by faulty installation misapplication abrasion corrosion inadequate or improper maintenance negligence accident tampering or substitution of non Graco component parts Nor shall Graco be liable for malfunction damage or wear caused by the incompatibility of Graco equipment with structures accessories equipment or materials not supplied by Graco or the improper design manufacture installation operation or maintenance of structures accessories equipment or materials not supplied by Graco This warranty is conditioned upon the prepaid return of the equipment claimed to be defective to an authorized Graco distributor for verification of the claimed defect If the claimed defect is verified Graco will repair or replace free of charge any defective parts The equipment will be returned to the original purchaser transportation prepaid If inspection of the equipment does not disclose any defect in material or workmanship repairs will be made at a reasonable charge which charges may include the costs of parts labor and transportation THIS WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ANY OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO WARRANTY OF MERCHANTABILITY OR WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE Grac
15. o s sole obligation and buyer s sole remedy for any breach of warranty shall be as set forth above The buyer agrees that no other remedy including but not limited to incidental or consequential damages for lost profits lost sales injury to person or property or any other incidental or consequential loss shall be available Any action for breach of warranty must be brought within two 2 years of the date of sale GRACO MAKES NO WARRANTY AND DISCLAIMS ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE IN CONNECTION WITH ACCESSORIES EQUIPMENT MATERIALS OR COMPONENTS SOLD BUT NOT MANUFACTURED BY GRACO These items sold but not manufactured by Graco such as electric motors switches hose etc are subject to the warranty if any of their manufacturer Graco will provide purchaser with reasonable assistance in making any claim for breach of these warranties In no event will Graco be liable for indirect incidental special or consequential damages resulting from Graco supplying equipment hereunder or the furnishing performance or use of any products or other goods sold hereto whether due to a breach of contract breach of warranty the negligence of Graco or otherwise FOR GRACO CANADA CUSTOMERS The Parties acknowledge that they have required that the present document as well as all documents notices and legal proceedings entered into given or instituted pursuant hereto or relating directly or indirectly he
16. r coded pneumatic pressure line from the air inlet fitting on the valve to the color coded cycle air outlet on the air supply controller 2 Turn on the electric and air supply 3 Setthe air pressure to 70 psi 4 8 bar on the system pressure gauge 4 n the normal rest position the Pinch off Piston 11 is held back by the Springs 10 sealing the Material Hose 18 o Momentarily press the dispense valve cycling control switch The Pinch off Piston 11 is pressurized to release the Material Hose 18 The controller air solenoid valve should cycle and cause a slight fluctuation in the system pressure gauge When this happens the system is correctly installed MATERIAL LOADING REMOTE MOUNTED MATERIAL SUPPLY Connect the Material Hose either directly to the material supply reservoir or to material supply tubing that connects to the material supply reservoir When using a remote reservoir the material supply tubing and fittings must be compatible with the material being dispensed and be capable of withstanding the dispensing pressure WET SYSTEM CHECKOUT Using the purge cycle on the air supply controller run the material through the dispense line until a smooth material flow is observed through the dispensing outlet After the purge cycle has been completed set the air supply controller to the manual cycle mode and cycle the Dispense Valve several times GRACO PERIODIC MAINTENANCE MATERIAL HOSE RENEWAL Material hose lif
17. reto be drawn up in English Les parties reconnaissent avoir convenu que la r daction du pr sente document sera en Anglais ainsi que tous documents avis et proc dures judiciaires ex cut s donn s ou intent s la suite de ou en rapport directement ou indirectement avec les proc dures concern es Graco Information For the latest information about Graco products visit www graco com TO PLACE AN ORDER contact your Graco distributor or call to identify the nearest distributor Phone 612 623 6921 or Toll Free 1 800 746 1334 Fax 330 966 3006 All written and visual data contained in this document reflects the latest product information available at the time of publication Graco reserves the right to make changes at any time without notice For patent information see www graco com patents Original Instructions This manual contains English MM 332096 Graco Headquarters Minneapolis International Offices Belgium China Japan Korea GRACO INC AND SUBSIDIARIES P O BOX 1441 MINNEAPOLIS MN 55440 1441 USA Copyright 2010 Graco Inc All Graco manufacturing locations are registered to ISO 9001 www graco com
18. sure that they are clean have no cuts or flat spots and contain NO foreign material Also be sure not to soak them in solvent for extended periods as this can cause deterioration of the seal Always replace U cups that are cut have flat spots are distorted in shape or are damaged in any manner Always be alert to the proper orientation of the sealing lips and re install them in the same direction as shown on the specific equipment assembly drawing The U cup seals are intended to seal in only one direction and if installed incorrectly chemical leakage through the U cup can occur e Whenever possible push the back side of the seal over the shaft to protect the inner and outer lips If this is not possible carefully tuck the lip in to avoid rolling it back or cutting it If installing over sharp edges slide the seal carefully into place to avoid cutting it Do not use any sharp tools or objects to install U cups 13 GRACO Graco Standard Warranty 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 This warranty applies only when the equipment is i
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