Measuring and testing – With fluid pressure – Clamp – plug – or sealing feature
Reexamination Certificate
2002-03-08
2004-01-13
Williams, Hezron (Department: 2856)
Measuring and testing
With fluid pressure
Clamp, plug, or sealing feature
C073S046000, C073S049200, C073S049800, C073S04050R, C138S090000, C138S089000
Reexamination Certificate
active
06675634
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a test plug and method for isolating and pressure testing a connection between a tank, vessel, or pipe and a nozzle or branch pipe extending externally therefrom.
BACKGROUND OF THE INVENTION
Site specifications, applicable design codes, and/or applicable testing codes typically require testing of new or modified piping, tank, and/or vessel systems including the testing of connections made between all piping components. The testing can be, for instance, a positive pressure test or a vacuum test and must verify the structural integrity of the system and determine if any leaks exist within the system, particularly at pipe connection locations. U.S. Pat. No. 5,797,431 issued to Adams, which is assigned to EST Group Inc., the assignee of present application, and U.S. Pat. No. 5,024,079 issued to Dufort disclose examples of known test plugs.
The Adams patent discloses a test plug which is used to seal a non-flanged end of a pipe. To this end, the test plug is inserted into the open end of a pipe and expanded to grip and form a fluid-tight seal with an inner peripheral surface of the pipe. Thus, the pipe can be pressure tested downstream of the inner diameter test plug while the test plug provides a fluid-tight seal and prevents the plug from being blown out of the pipe during high test pressure conditions.
The Dufort patent discloses a test plug for a flanged pipe in which an expandable distal end of the plug is inserted into the pipe and an opposite flanged end of the plug is connected to a flanged-end of a pipe to create a fluid-tight seal. For instance, see
FIGS. 4-6
of the Dufort patent. When the distal end is expanded, it also creates a fluid-tight seal so that the weld between the pipe and the flange of the pipe can be pressure tested. To this end, fluid is injected into the flanged end of the plug and only the flanged end of the pipe is tested so that the remaining piping system is not required to be placed under pressure during the pressure testing of the flange connection.
While the above referenced test plugs function satisfactorily for their intended purposes, they cannot be utilized to isolate and test a connection, such as a welded connection, between a tank, vessel, or pipe and a branch pipe or nozzle, without having to pressurize the entire tank or vessel or a large portion of the piping system. For example,
FIGS. 1A-1C
of the present application illustrates a section
10
of a hollow, cylindrical, relatively large diameter pipe, tank or vessel and an externally-extending, relatively smaller diameter, flanged branch connection
12
. The flanged branch connection
12
can be, for instance, a relatively smaller diameter branch pipe or tank nozzle. An interior weld location
14
or an exterior weld location
16
can be utilized, for example, to join the flanged branch connection
12
to section
10
. The relative diameters of section
10
and branch connection
12
can vary widely and are not required to have a circular transverse cross-section, as illustrated.
In the construction of such systems as shown in
FIGS. 1A-1C
, inlets, outlets, welded fittings, nozzle connections and branch line connections
12
are made transversely through the periphery of the relatively larger diameter pipe, vessel or tank section
10
. As best shown in
FIGS. 1B and 1C
, an inner end
18
of the branch connection
12
typically extends entirely within the larger diameter pipe, tank or vessel section
10
. The opposite end
20
of the branch connection
12
can be connected by a weld
22
to a flanged end
24
as illustrated in
FIGS. 1A-1C
, or can be without a flange end as best illustrated in
FIG. 8
of the present application as will be discussed in greater detail. Typically, if such systems are made from steel components, the connections are made utilizing welding techniques; however, other known techniques can also be utilized to join the various components. As stated above, typically the various components are cylindrical, however, the various joined components can have, for instance, rectangular, square, spherical, or oval transverse cross sections.
Conventionally, pressure testing of the internal or external welds
14
or
16
of the branch connection
12
to section
10
is accomplished by pressurizing the entire piping system, tank or vessel, or a large part of the piping system. Thus, such testing is time consuming, expensive, and can create potential hazards. In addition, welding operations utilized to join a branch connection
12
to an existing section
10
of a piping system, tank or vessel may be performed in the presence of combustible, dangerous, and/or otherwise harmful materials or vapors which are present within the existing piping system, tank or vessel. Thus, the welding operation as well as the testing operation may be subject to potential hazards.
Various patents disclose pipe, tank, or vessel testing or repair apparatus and methods. For example, U.S. Pat. No. 5,760,296 issued to Wilson discloses the use of an inflatable bladder to form a fluid-tight seal with an inner wall of a vessel adjacent a nozzle. The bladder is inserted through an opening in the nozzle and is positioned within the vessel before being inflated. The disclosed pressure testing device is designed to isolate the vessel from the nozzle so that the vessel can be pressure tested, not the vessel-to-nozzle weld connection.
U.S. Pat. No. 5,996,401 issued to Lewis discloses a leak test adaptor system that attaches to a vessel via a test port and permits the vessel to be filled with a tracer gas or fluid so that the vessel and the test port can be simultaneously tested for leaks. A plug is located within the test port and is manipulated between sealing and non-sealing positions by a rod which extends externally of the vessel. Thus, an adaptor can be connected to the test port to open the plug, fill the vessel with a tracer gas, and close the plug to test for leaks.
U.S. Pat. No. 5,331,841 issued to Beaver et al. discloses a process and apparatus for repairing a damaged surface of a nozzle extending from a vessel. To this end, a new inner nozzle is installed within the damaged nozzle to line the damaged nozzle, and a seal is formed at both ends of the new inner nozzle to create a leak-free repaired nozzle. As illustrated in
FIG. 8
of the Beaver patent, a gasket can be utilized to form a seal between the inner wall of the tank and the end of the new nozzle inserted within the tank.
U.S. Pat. No. 6,131,441 issued to Berube et al. and U.S. Pat. No. 4,890,843 issued to Vetter disclose other devices for isolating and testing pipe segments.
Although the test plugs and methods of isolating and testing pipe sections and/or tanks and vessels disclosed in the above referenced patents may function satisfactorily for their intended purposes, there remains a need for a test plug device and method which enables ready isolation and testing of a connection, such as a welded connection, between a tank, vessel, or pipe and a branch pipe or nozzle. Preferably, the test plug should isolate the connection from the tank, vessel or remaining piping system to enable testing of the connection without requiring the entire tank or vessel or a large section of the piping system to be pressurized. In addition, preferably the test plug should isolate a welding operation from harmful materials or vapors existing within the tank, vessel or piping system and should permit an inert gas to be utilized to flush any potentially harmful vapors or the like away from the area to be welded. Further, the test plug and method should permit reliable, ready and efficient installation and use requiring only a minimum of skill and labor, and the test plug should be inexpensive to manufacture.
OBJECTS OF THE INVENTION
With the foregoing in mind, a primary object of the present invention is to provide a test plug which enables ready isolation and testing of a connection, such as a welded connection, between a tank, vessel, or pipe and a branch pipe or nozzle.
Another object of the present
Berneski, Jr. James P.
Brandenberger Henry
EST Group, Inc.
Howson and Howson
Jackson André K.
Williams Hezron
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