Plastic fitting for flared tubing

A combination of a plastic fluoropolymer fitting and a plastic fluoropolymer tube, the fitting for coupling to a flared end of the tube, said flared end having an elongated “S” shape in the cross section, the tubing having a first tubing portion of a first diameter integral with a curvilinear transition portion, and a second tubing portion having a wall thickness and a second diameter integral with the curvilinear transition portion and concentric with the first tubing portion, said fitting comprising:

• a fitting body with a first end and a second end and a flow conduit extending therethrough, the first end having a recess with inwardly facing threads with a tapered nose section inset therein, the tapered nose section having a curvilinear side wall configured to cooperate with the curvilinear transition portion of the tubing,
• a fitting nut operably joinable to said fitting body in the recess, said fitting nut having exterior threads sized to cooperate with the inwardly facing threads of the fitting body and a flare-engaging collar, the collar having a pair of annular contact points with a gap therebetween and with the nut having a bore sized to slidingly fit on the first tubing portion;
• whereby upon tightening of the fitting nut into the recess of the fitting body with the flared end of the tubing therein, the corner contacts the flared end and seals same against the curvilinear sidewall of the nose section.

A combination of a plastic fluoropolymer fitting and a plastic fluoropolymer tube, the fitting for coupling to a flared end of the tube, said flared end having an elongated “S” shape in the cross section, the flared end of the tubing having a first tubing portion of a first diameter integral with a curvilinear transition portion, and a second tubing portion having a wall thickness and a second diameter integral with the curvilinear transition portion and concentric with the first tubing portion, said flared end having a contiguous interior smooth surface extending throughout said “S” shape, said fitting comprising:

• a fitting body with a first end and a second end and a flow conduit extending therethrough, the first end having a recess with inwardly facing threads with a tapered nose section inset therein, the tapered nose section having a curvilinear side wall configured to cooperate with the curvilinear transition portion of the tubing and a cylindrical surface configured to engage with the second tubing portion of the flared end,
• a fitting nut operably joinable to said fitting body in the recess, said fitting nut having exterior threads sized to cooperate with the inwardly facing threads of the fitting body and a flare-engaging collar for engaging the flared end, the nut having a bore sized to slidingly fit on the first tubing portion;
• whereby upon tightening of the fitting nut into the recess of the fitting body with the flared end of the tubing therein, the collar contacts the flared end and seals the flared end against the curvilinear sidewall and the cylindrical surface of the nose section.