In today's energy conservation conscious world, finding ways to better insulate our homes, is foremost on the minds of a great many people. Many different materials have been used for such insulation. For example, fiberglass insulation provides good insulation characteristics for insulation of walls, ceilings, etc. of homes. However, a large number of homes have submerged or at least partially submerged bottom floors or cellars. The walls of this area of the home are typically fabricated from cinder block, equivalently concrete block, with essentially no insulation.
Polyurethane and polyisocyanurate foams are well-known as effective insulation materials. However, using such prior polyurethane or polyisocyanurate foams to retrofit block wall cavities with insulation has met with certain difficulties. First, the polyurethane or polyisocyanurate insulating foams have been too dense to make them economical as insulation for wall cavities. Moreover, the prior polyurethane or polyisocyanurate foams used to retrofit wall cavities with insulation have had other problems because they have rise times which greatly exceed their gel or set times. Thus, such a foam first sets within the wall cavity to such an extent that the pressure generated within the cavity causes damage as the foam completes its expansion.
Therefore, it is easily seen that what is needed is a way to dispense foam into cavities in which foam rise times are matched to gel or set times as well as control of the final foam characteristics, i.e., closed cell foam.