Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION:
Pipeline pig for detecting an obstruction in a pipeline and method.
FIELD OF THE INVENTION
The present invention relates to a pipeline pig, the purpose of which is to
check an
interior of a pipeline for obstructions and a method of use of the same.
BACKGROUND OF THE INVENTION
Various pipeline pigs have been developed for the purpose of checking the
interior of
a pipeline for obstacles which might impede the movement of pipeline
inspection devices
in the pipeline or to locate change in diameter that may require attention.
Calliper pigs
used in pipelines provide internal pipe measurements, but they are expensive
to operate.
These pigs monitor all restrictions along a pipeline, regardless of size, and
will normally
collect a significant amount of data that requires interpretation by a
technician or computer
programs.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a method
for
detecting an obstruction in a pipeline. A first step involves providing a
pipeline pig which
2 0 carries an impression substrate and a contact sensor. A second step
involves passing the
pipeline pig along a pipeline. The contact sensor emits a signal should an
internal obstruction
be encountered. The obstruction leaves an impression upon the impression
substrate that is
indicative of the size and circumferential positioning of the obstruction.
2 5 According to another aspect of the present invention there is provided a
pipeline pig
for detecting an obstnrction in a pipeline, which includes a body adapted to
slide along an
interior of a pipeline. A contact sensor is carried by the body. The contact
sensor is adapted
to produce a signal upon an internal obstruction being encountered. An
impression substrate
is carried by the body which, upon being struck by the obstruction, is adapted
to be marked by
3 0 an impression that is indicative of the size and circumferential
positioning of the obstruction.
BRIEF DESCRIPTION OF THE DRAWINGS
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These and other features of the invention will become more apparent from the
following description in which reference is made to the appended drawings, the
drawings are
for the purpose of illustration only and are not intended to in any way limit
the scope of the
invention to the particular embodiment or embodiments shown, wherein:
FIG.1 is a simplified side elevation view, in section, of a first embodiment
of pipeline
pig constructed in accordance with the teachings of the present invention.
FIG. 2 is a simplified side elevation view, section, of the pipeline pig
illustrated in
FIG.1, encountering an obstacle.
FIG. 3 is a simplified side elevation view, in section, of a second embodiment
of
pipeline pig constructed in accordance with the teachings of the present
invention.
FIG. 4 is a front elevation view of a first embodiment of resilient member
used in the
pipeline pig illustrated in either FIG.1 or FIG. 3.
FIG. 5 is a front elevation view of a second embodiment of resilient member
used in
the pipeline pig illustrated in FIG.1 or FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Prefewed embodiments of pipeline pig will now be described with reference to
FIG.1
through 5. A first embodiment of pipeline pig, generally identified by
reference numeral 100,
2 0 will be described with reference to FIG. 1 and 2. A second embodiment of
pipeline pig,
generally identified by reference numeral 200, will be described with
reference to FIG. 3.
Structure and Relationship of Parts:
Referring to FIG. 1 and 2, pipeline pig 100 is provided with supporting rubber
2 5 rings 10, 12 connected in series, one after the other. A front securing
bolt 40, a rear
securing bolt 38, an intermediate cylinder pig body 14, serve to connect and
maintain the
relative spacing of rubber rings 10 and 12. Ring 12 is securely fixed to the
front of pig
body 14 and ring 10 is fixed to the rear of pig body 14. The two rings 10-12
are at a
constant spacing allowing the pig to be transported along a pipe.
A generally disk-shaped resilient member 20 ai~xed to carrier 24 by holder 21
and
23 are held in place by spacers 26 and 18. The pig is constructed so that
either the resilient
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member 20 or the resilient de-formable member 42 is electrically conductive
and is
directly connected to electronics in electronics carrier 28. Carrier 24 is
free to rotate
around the cylinder body 14. Electronic carrier 28 and odometer assembly 30 is
attached
to carrier 24 causing carrier to be out of balance and force it to always
rotate to the same
position. As carrier 24 is free to rotate around body 14, the same segment of
the resilient
disc 20 will always be located at the six o'clock position. Thus when
examining the
resilient de-formable member 42 one can determine the clock location, size and
shape of
the restriction encountered. Member 42 can be made from resilient material
such as thin
metal or plastic. The resilient member 20 can be a complete unit, as
illustrated in FIG. 4
or segmented as shown in FIG. 5 to allow for multiple indications showing and
recording
the clock position of each. Referring to FIG. 1 and 2, each segment of 20 is
individually
electrically connected to electronics in carrier 28 thus when different
sections of the
resilient member 20 contact pipe 32 the electronics will record the occurrence
of the event
and which segment made contact. The resilient member 20 has a smaller outside
diameter
than the inside diameter of the pipe 32. Resilient member 20 thus defines an
annular void
space 45 between its outer surface and the inner surface of the pipeline wall.
The radial width of the void 45 is predetermined and depends on the
operational
requirements of a particular application. It generally corresponds to the
maximum
2 0 tolerable size of restriction at the inner surface of the pipeline 32 or
industry code
requirements.
Variations:
2 5 FIG. 3 shows pipeline pig 200, which is the same as pipeline pig 100, with
the
exception of the addition of resilient members 22 and 44. Any number of
elements can be
added. The number would be a function of the objective of the run.
3 0 Operation:
Pipeline pig 100 is propelled through the pipeline typically by a pressure
differential at the front and rear ends of the pig, moving from the left to
the right of FIG.1
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and 2. Referring to FIG. 2, if an obstacle is encountered along the wall of
the pipeline,
which is radially in excess of the width of the void 45, the resilient member
20 or the
respective segment 20 of the resilient member 20 is in contact with pipe 32.
When contact
is made between the resilient member 20 and pipe wall 32, a conductive circuit
is
completed as wheel assembly 30 is in contact with pipe 32. A circuit can also
be
completed by having rubber either ring 10 or 12 made of conductive material.
Referring to
FIG. 1, another alternative is placing a wire brush assembly 52 can be placed
in front of
rubber ring 10. The occurrence is recorded by the electronics in holder 28. As
a result,
information is now available that an obstacle, for instance, a partly closed
valve or a dent,
has been encountered. Eventually, the resilient member runs over the obstacle,
the resilient
member 20 returns to its position and is set to respond to another obstacle.
Referring to FIG. 3, by using multiple resilient different size members 20,
22, one
can determine if the obstacle encountered is more substantial. Any number of
resilient
members can be used.
Referring to FIG. 1 and 2, a de-formable and mark-able resilient member 48
made
of electrically conductive material the same as member 20 and a resilient mark-
able
member 48, for instance, of a mark-able, relatively thin sheet metal or
plastic can be
2 0 mounted at the rear end of the pig. Its purpose is to determine if events
recorded by the
electronics are a result of the pig travelling through a bend or if the event
was a result of a
restriction. If at times the electronics malfunction and fail to give an
indication of an
obstacle, then such obstacle inevitably deforms the resilient mark-able
members 42 and 50
will show that an event has occurred thus providing information that in fact
there had been
2 5 failure to electronically monitor an obstacle was encountered. If there
was no record of an
obstacle and the mark-able resilient members are not be deformed, this would
confirm that
indeed no obstacle is present in the inspected section.
Whenever the pig detects a restriction, time may be recorded and saved for
3 0 analysis at the end of the inspection run. The information recorded may be
fed to a
computer that will correlate the time the restrictions were encountered with
other tracking
information and pipeline geographic position.
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In this patent document, the word "comprising" is used in its non-limiting
sense to mean that items following the word are included, but items not
specifically
mentioned are not excluded. A reference to an element by the indefinite
article "a" does not
5 exclude the possibility that more than one of the element is present, unless
the context clearly
requires that there be one and only one of the elements.
It will be apparent to one skilled in the art that modifications may be made
to the
illustrated embodiment without departing from the spirit and scope of the
invention as
hereinafter defined in the Claims.
