A Spray Foam Gun is precisely engineered pieces of equipment that perform the most critical functions of the SPF application process: mixing the chemical components and spraying it to the target substrate. The vast majority of polyurethane foam spray guns on the market use impingement-mixing technology to combine the chemicals inside the gun. When the trigger is pulled, equal amounts of the two chemical components enter the mixing chamber, where they begin to react. Because the fluid is under pressure, the mixture is immediately forced out of the chamber through a small orifice, thereby atomizing into a spray as it exits the gun.
It is important to understand that if the all of the reacted material is not expelled from the gun once the trigger is released, the material will start to cure and harden inside the Spray Foam Gun, rendering it unusable. So, it is critical to completely remove, or purge, the gun of every particle of reacted material. There are three ways to do this, each representing a different class of Spray Foam Gun: mechanical purge, air purge, and solvent purge.
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