Foam spray gun hoses which prevent crossover

A variably tensionable check valve with a first end and a second end comprising:

• a housing, hex jam screw, a spring, and a metallic sphere biased in a closed position,
• wherein said housing comprises a first portion and a second portion,
• wherein said first portion comprises a first external sealing surface that provides a leak-proof connection with a dispensing gun, a second external sealing surface capable of securing said check valve to said dispensing gun, a transition portion, and a substantially cylindrical first internal passageway,
• wherein said first internal passageway comprises a threaded surface and a smooth surface, and
• wherein said transition portion forms a pair of tangential planes forming an angle of about ninety degrees,
• wherein second portion comprises a third external sealing surface and a substantially cylindrical second internal passageway,
• wherein a diameter of said smooth surface of said first internal passageway is greater than a diameter of said second internal passageway, and
• wherein said transition portion is interposed between said first internal passageway and said second internal passageway,
• wherein said hex jam screw, said spring, and said metallic sphere are located within said first internal passageway,
• wherein said hex jam screw secures said spring and said metallic sphere within said first internal passageway, and
• wherein rotational movement of said hex jam screw modifies a biasing force of said spring.

A variably tensionable check valve with a first end and a second end comprising:

• a housing, a tension adjuster, a resiliently deformable elastic member, and a flow restriction member biased in a closed position,
• wherein said housing comprises a first portion and a second portion,
• wherein said first portion comprises
• means for sealing said check valve to a dispensing gun,
• means for securing said check valve to said dispensing gun,
• a transition portion, and
• a first internal passageway,
• wherein said first internal passageway comprises means for securing said tension adjuster,
• wherein second portion comprises means for securing said check valve to a hose and a second internal passageway,
• wherein a surface area of a cross-section of said first internal passageway is greater than a surface area of a cross-section of said second internal passageway, and
• wherein said transition portion is interposed between said first internal passageway and said second internal passageway,
• wherein said tension adjuster, said elastic member, and said flow restriction member are located within said first passageway, and
• means for securing said elastic member and said flow restriction member within said first passageway.