The present invention relates, in general, to insulated steam injecting tubing and, in particular, to a new and useful device for sealing a port that communicates with an annular space between inner and outer tubulars of the unsulated steam injecting tubing, to maintain a vacuum in that space which was drawn through the port.
U.S. Pat. No. 4,396,211 to McStravick et al discloses an insulated tubular conduit for use in forming a tubing string a subterranean well. The conduiit comprises inner and outer tubing with an annular cavity formed therebetween. A fixture is provided for evacuating the gases from the annular cavity. This fixture include a clamp extending around the exterior of the outer tubing. A passage extends radially through the fixture and communicates with an evacuation port in the outer tubing. A plug, such as a tapered pin, surrounded by an annular seal, can be inserted into this passage. A vacuum hose connected to the fixture and communicating with the passage can be connected to a vacuum pump for drawing a vacuum from the annular cavity. After a suitable vacuum has been drawn, the pin which is a tapered pin, is driven into the vacuum port to close the annular cavity.
U.S. Pat. No. 1,472,019 to Hitch discloses a double walled receptacle in the form of a bottle having an outer shell and an inner shell wherein an air chamber is provided between the inner and outer shells. A tapered air passage is formed in the outer shell. A sleeve is clamped to the receptacle and provides a passageway and communication with the tapered air passage which, in turn, provides a passage for drawing air form the air chamber. A driver bar fits within the sleeve passageway and a tapered plug is supported on the end of the driver bar. After an appropriate vacuum has been created in the chamber, the driver bar is struck with a tool to drive the plug into the tapered air passage to seal the chamber. A similar device for sealing off a metal tank is disclosed in U.S. Pat. No. 2,032,862 to Wilkins. In this patent, a ram is used to force a sealing plug into a chamfered and slightly tapered opening in a tank. An end of the ram carries a spring wire holder and over this holder, there is a forced plug. The plug is drilled at the surface which contacts the ram. The hole is of a size sufficiently small to permit the plug to be pressed tightly over the holder and to be securely attached thereto.
None of the patents discussed above discloses the provision of a breakable tab portion between a plug portion and a shank portion of a pin which is driven into an aperture of an outer tube to seal the annulus between the outer and inner tube. These features, however, are found in the present invention and distinguish it from the older patents.
Other references which are of interest to the present application are as follows:
U.S. Pat. No. 29,582 to Gill PA1 U.S. Pat. No. 30,440 to Wildey PA1 U.S. Pat. No. 311,253 to Mussel PA1 U.S. Pat. No. 1,150,242 to Bartlett PA1 U.S. Pat. No. 1,463,723 to Otsuki PA1 U.S. Pat. No. 1,848,319 to Clifford PA1 U.S. Pat. No. 2,016,045 to Munters PA1 U.S. Pat. No. 2,367,756 to Cummings PA1 U.S. Pat. No. 3,065,583 to Miller PA1 U.S. Pat. No. 3,240,227 to Burkholder PA1 U.S. Pat. No. 3,406,987 to Hunder et al.