June 20, 2007

Flushing Procedure - Polyurethane Foam (PUF) and Polyurea/Polyurethane Coatings

This paper has been written to give the Applicator sufficient knowledge to flush Gusmer equipment of polyurethane foam materials and polyurea/polyurethane/hybrid materials prior to changing material systems or storage of equipment.

DISCLAIMER:
Gusmer has made every effort to make the information provided accurate to the best of its knowledge, however, due the variety of uses and applications for Gusmer equipment, and changes that may have been made to the equipment subsequent to the publishing of this procedure, there may well be information that is missing or not applicable to particular circumstances.

GENERAL SAFETY INFORMATION
Extreme care must be taken. Polyurethane and polyurea materials, especially the Isocyanate materials are reactive with water in any form. It is necessary to understand and follow the instructions in this paper to insure proper and safe operation of the equipment.
Sufficient guidelines cannot be developed to eliminate the need for good common sense in the use and flushing of the equipment, and in the use and application of the products, this equipment is designed to process. Users of this equipment must therefore, make their own determination as to the suitability of the information contained herein. There should be no assumption made that the instructions and safety measures herein are all inclusive, and that other measures may not be required for the specific use or application.

SOLVENTS and CHEMICALS
It is the user’s responsibility to insure that adequate personal protection measures are taken so as not to exceed the Threshold Limit Value (TLV) of the products being used, as established by the Occupational Safety and Health Administration (OSHA) or other qualified agency. The user must be aware of the exposure limits specified for the products being used, and must use them in accordance with the recommendations specified by their manufacturer.

PERSONAL PROTECTION
The use of solvents will be required when servicing or cleaning Gusmer equipment. To prevent excessive exposure to the solvents, appropriate personal protective gear such as eye and face protection, respiratory protection and protective gloves and clothing may be required.

REQUIRED SOLVENTS
Dioctylphthlate (DOP) or equivalent plasticizer – approximately 8 gallons
N-Methyl Perildone (Solvent) or equivalent solvent – approximately 5 gallons

Important: Before doing this procedure or any other chemical change, insure compatibility between the old and new Iso and Polyol and required solvents.

PROCEDURE
1. Remove Spray Gun and Coupling Block from hose ends and secure ends into a single trash bag.
2. Lower material dispensing pressure by decreasing air pressure to 30 psi (air operated) or decreasing hydraulic pressure to 300 psi.

3. Fill two separate 5-gallon buckets with a flushing solution of 2-gallons of DOP and 2-gallons of Solvent.

4. If using the same Transfer Pumps and Supply Hoses, remove them from the material drums, and if possible lift the inlet balls to drain material from inside the Transfer Pump. Wipe the exterior of the pump with a clean rag. Insert each Pump in a separate bucket and secure to insure tipping is not possible.

5. Actuate the proportioner to move slowly and purge both chemicals into the bag.
Caution: Do not actuate the Primary Heaters or Heated Hoses
The subsequent reacted material can be disposed of into a trash container. Stop the proportioner as soon as the chemical is voided and the Flushing solution follows.
6. Collect the first gallon of Flushing solution from the material hose ends and safely dispose of the solutions in accordance with applicable federal, state, and local regulations.
7. Securely fasten the material hose ends into their respective buckets of Flushing solution and begin to recycle the Flushing solution. Recycle at the fastestproportioner cycle rate possible without creating a safety hazard. Effective flushing is a function of velocity (rate at which the Flushing solution travels) not gallonage (amount of Flushing solution).
8. Allow Flushing solution to re-circulate for at least one (1) hour.
9. Turn off proportioner and remove the Transfer Pumps from the Flushing solution. If possible, lift the inlet balls to drain material from inside the Transfer Pump. Wipe the exterior of the pump with a clean rag. Insert each Pump in a single bucket filled with three (3) gallons of DOP and secure to insure tipping is not possible.
10. Actuate the proportioner to move slowly and purge all remaining Flushing solution out into the two buckets, filling the proportioner with only DOP. Safely dispose of the Flushing solution in both buckets in accordance with applicable federal, state, and local regulations. Stop the proportioner and insure all pressure is removed from the proportioning unit and material hoses.

11. New Material: Reinstall the Coupling Block. Actuate the proportioner to move slowly and purge all remaining DOP out into a bucket, filling the proportioner with the new material. Safely dispose of the DOP in accordance with any applicable federal, state, and local regulations.

12. Storage: Reinstall the Coupling Block and Spray Gun. Set R.O.N switch to Retract. Add pressure to air motor/hydraulic cylinder to develop 1,000 psi. Trigger Spray Gun until pump is in the retract position and pressure falls to 500 psi. Secure machine with all valves closed and power off. Remove Spray Gun and ensure Coupling Block is clean.