초록 ▼

A hot melt foam adhesive system including a gear pump wherein gas is mixed under pressure into the molten adhesive and is driven into solution with the adhesive. The adhesive/gas solution is supplied at a relatively high pressure to a valved dispenser or gun from where it is dispensed onto a substra

A hot melt foam adhesive system including a gear pump wherein gas is mixed under pressure into the molten adhesive and is driven into solution with the adhesive. The adhesive/gas solution is supplied at a relatively high pressure to a valved dispenser or gun from where it is dispensed onto a substrate. As the adhesive/gas solution emerges from the dispenser, the gas comes out of solution but remains entrapped in the adhesive, thereby forming an adhesive foam. The system includes a recycle flow line or hose for returning adhesive/gas solution from the dispenser to the pump. Within this recycle flow line there is a pressure regulator responsive to flow changes or viscosity changes of the adhesive/gas solution for maintaining a fixed back pressure in the system, thereby enabling the system to maintain a fixed and uniform flow rate from the dispenser during all operating conditions of the dispenser.

대표청구항 ▼

Apparatus for dispensing a foamed adhesive or sealant material, said apparatus comprising, a pump, means for supplying said material in a liquid state to said pump, a source of gas, means for supplying gas from said source to said pump such that said pump is operable to agitate said liquid material

Apparatus for dispensing a foamed adhesive or sealant material, said apparatus comprising, a pump, means for supplying said material in a liquid state to said pump, a source of gas, means for supplying gas from said source to said pump such that said pump is operable to agitate said liquid material in the presence of the gas so as to distribute said gas throughout said liquid material and to pressurize said liquid material and gas to place said gas into solution with the liquid material, means for dispensing said liquid material and gas solution at a pressure below the solution maintenance pressure of said liquid material and gas solution whereby the gas is released from solution as said liquid forms a foam, first fluid conduit means for supplying said liquid material and gas solution from said pump to said dispensing means, second fluid conduit means for recycling said liquid material and gas solution from said dispensing means back to said pump, third fluid conduit means including a spring biased pressure relief valve means for interconnecting said first and second fluid conduit means, and a spring biased pressure regulator contained within said second fluid conduit means for maintaining a substantially constant back pressure of liquid material and gas solution within said dispensing means, and said pressure regulator including a variable orifice and means including a fixed orifice restrictor responsive to changes in flow and changes in the viscosity of liquid material and gas solution flowing through said pressure regulator to vary the size of said variable orifice.