Tech Tip - Circulation of Open Cell, Water Blown Foams

When processing Demilec open cell foam it is important to circulate the A and B components prior to application. Circulation aids in increased yield and productivity, better physical properties of the insulation system, and maximizes the delta T of the proportioner that is being used to process the foam insulation.

Materials Needed:

• Circulation Block/Manifold - P/N 246362
• Complete Circulation Kit – P/N recirculation-kit
• Drum Mixer – P/N: electric mixer
• Thermometer – P/N

It is important to circulate both the A and B drums of chemical up to 90F-100F degrees before application. While maintaining a constant flow of chemical from the transfer pumps or in JOG mode or a combination of the two, the proportioners pre-heaters and hose heat will be used to heat the drums to a consistent temperature. Once the chemical in the drums reaches 90F-100F, the circulation process can stop and processing can begin.

When checking the temperature of the drums during circulation, it is important to use an inline thermometer or digital infrared thermometer.

While maintaining 1”-2” average from the outer surface of the drum, point the digital thermometer at the drum and scan from top to bottom, the temperature should be an approx average. If the chemical at the bottom of the drum is cooler than the top, allow the mixing to continue until an approx average is noticed before starting to apply.

Sealectionopen cell foams may have slight separate at a temperature greater than 110F-120F, because of this we need to mix the material in the drum while circulating. The mixer that is used should be pneumatic or electric, electric mixers are preferred because accurate rpm adjustments can be made. It is important to constantly mix the resin (B-side) during and after circulation at a rate of 50-70rpm.

CAUTION: Circulation is for open cell, water blown foams only, in no case should closed cell foams containing the blowing agent 245FA be circulated. It is important to maintain temperatures below 75f for foams containing 245FA.

As always read, understand and follow all instruction manuals and warning labels supplied with all equipment. Only trained and qualified personnel should perform repairs on the equipment. To access the latest equipment manuals visit www.graco.com.

Additional information can be found in the Sealection Installers Manual or by contacting any one of Demilec USA’s technical service representatives.

As always read, understand and follow all instruction manuals and warning labels supplied with all equipment. Only trained and qualified personnel should perform repairs on the equipment. To access the latest equipment manuals visit www.graco.com.