HIGH PRESSURE FITTING
A fitting assembly for a high pressure system includes a tube assembly including a tube having an undercut near a first end. A gland is slidably coupled around the tube and has an exterior threaded surface. The gland forms a gland cavity adjacent an exterior surface of the tube. A spring collar is also slidably coupled around the tube between the gland and the first end of the tube such that a portion of the spring collar is disposed within the gland cavity. The fitting body has an inlet passage and a fitting cavity for receiving an end of the tube assembly. The open end of the fitting cavity has a threaded surface forming a threaded engagement with the threaded surface of the gland. This threaded engagement creates a primary and secondary seal in the fitting assembly. The secondary seal applies a force to the threaded engagement.
1 . A fitting assembly for use in a high pressure system comprising:
a tube assembly including:
a tube having an undercut near a first end;
a gland slidably coupled around the tube and having a threaded exterior surface, the gland forming a gland cavity adjacent an exterior surface of the tube; and
a spring collar slidably coupled around the tube between the first end and the gland such that a portion of the spring collar is disposed within the gland cavity; and
a fitting body having an inlet passage and a fitting cavity connected to the inlet passage into which an end of the tube assembly is received, an open end of the fitting cavity having a threaded inner surface engaged with the threaded exterior surface of the gland to form a threaded engagement such that a first seal and a second seal are formed between the tube assembly and the fitting body, wherein the second seal applies a force to the threaded engagement.
2 . The fitting assembly according to claim 1 , wherein the first seal is created between the end of the tube and the fitting cavity.
3 . The fitting assembly according to claim 1 , wherein the second seal is formed between the spring collar and the fitting cavity.
4 . The fitting assembly according to claim 3 , wherein the spring collar is engaged with the undercut of the tube.
5 . The fitting assembly according to claim 3 , wherein the spring collar includes a circumferential groove.
6 . The fitting assembly according to claim 1 , wherein the tube, spring collar, and gland are made of metal.
7 . The fitting assembly according to claim 6 , wherein the spring collar is made from a nickel-chromium alloy.
8 . The fitting assembly according to claim 1 , wherein an inner surface of the first end of the tube is chamfered.
9 . A method comprising:
providing a tube assembly including:
a tube with a first end and having an undercut near the first end;
a gland slidably coupled around the tube and having a threaded exterior surface, the gland forming a gland cavity adjacent an exterior surface of the tube; and
a spring collar being slidably coupled around the tube adjacent the gland such that a portion of the spring collar is disposed within the gland cavity; and
providing a fitting body having an inlet passage and a fitting cavity for receiving the tube assembly, the fitting cavity having an open end with a threaded inner surface for engagement with the threaded exterior surface such that when the threaded inner surface and the threaded exterior surface are engaged to form a threaded engagement, a first seal and a second seal are formed between the tube assembly and the fitting body, wherein the second seal applies a force to the threaded engagement.
10 . The method according to claim 9 , wherein the first seal is created between the end first of the tube and the fitting cavity.
11 . The method according to claim 9 , wherein the second seal is formed between the spring collar and the fitting cavity.
12 . The method according to claim 9 , wherein the tube, spring collar, and gland are made of metal.
13 . The method according to claim 12 , wherein the spring collar is made from a nickel-chromium alloy.
14 . The method according to claim 9 , wherein an inner surface of an end of the tube received within the fitting cavity is chamfered.
15 . A method of assembling a high pressure fitting comprising:
slidably coupling a gland and a spring collar around a tube such that a portion of the spring collar is positioned within a cavity formed between the gland and the tube and is located between the gland and a first end of the tube;
receiving the first end of the tube within the fitting cavity of the fitting body;
engaging a chamfered inner diameter of the first end of the tube with a complementary groove of the fitting cavity;
sliding the gland and spring collar along the surface of the tube until a portion of the spring collar contacts a ramp portion of the fitting cavity; and
engaging the threads of the gland with the threads of the fitting cavity.
16 . The method of assembling a fitting according to claim 15 , wherein engaging the threads of the gland with the threads of the fitting cavity applies a force to the spring collar causing an end of the spring collar to bend into an undercut on the tube.
17 . The method of assembling a fitting according to claim 15 , wherein the tube, spring collar, and gland are made of metal.
18 . The method of assembling a fitting according to claim 17 , wherein the spring collar is made from a nickel-chromium alloy.
19 . The method of assembling a fitting according to claim 15 , wherein a first seal is created between the end of the tube and the fitting cavity.
20 . The method of assembling a fitting according to claim 15 , wherein a second seal is formed between the spring collar and the fitting cavity.