Measuring and testing – Sampler – sample handling – etc. – Withdrawing through conduit or receptacle wall
Reexamination Certificate
1998-10-20
2001-11-20
Noland, Thomas P. (Department: 2856)
Measuring and testing
Sampler, sample handling, etc.
Withdrawing through conduit or receptacle wall
C073S864710
Reexamination Certificate
active
06318192
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the obtaining of contaminant samples which have been deposited along the interior surface of a pipe; and more particularly it concerns a novel method and apparatus for applying a large area swab to the inner surface of a pipe so that a representative sample of the contaminant can be recovered from the pipe without interfering with the flow of fluid through the pipe.
2. Description of the Related Art
Large diameter pipes, such as gas mains, are often required to convey gasses which may contain harmful contaminants such as polychlorinated biphenyls (PCBs) or Benzine. These contaminants may precipitate out of the gas stream and become deposited along the interior service of the pipe. Thereafter, when clean gas passes through the pipe, it comes into contact with the contaminant deposits so that it may also become contaminated.
It is therefore important, at any given time, to know whether sufficient contaminants have become deposited long the inner surface of a pipe such that they would be likely to cause further contamination of clean gas passing through the pipe. It is also important not to interrupt gas flow through the pipe or otherwise disrupt its operation while inspecting its inner surface for contaminants. This becomes a difficult problem in that in order to obtain an accurate indication of the condition of a pipe's inner surface, a minimum area of the surface, usually at least four square inches (25 square centimeters), must be examined; and to expose this much of a pipe's interior while maintaining normal gas flow through the pipe is especially difficult.
U.S. Pat. No. 5,269,968 discloses a technique for removing PCBs from the contaminated inner surface of a pipe by means of a swab sampling technique in which the pipe is first cut into pieces to expose its inner surfaces.
U.S. Pat. No. 5,686,674 discloses the use of a sensor which is dragged through the interior of a pipe to sense radioactive contamination along the inner surface of the pipe.
U.S. Pat. No. 4,919,892 discloses the use of a perforated housing which is positioned in the path of fluid flow in a pipe to absorb contaminants from the fluid passing through the pipe.
U.S. Pat. Nos. 5,463,908 and No. 5,531,130 relate to the use of probes which are inserted into pipes to measure conditions in the fluids which flow through the pipes.
U.S. Pat. Nos. 3,842,864, 3,910,298 and 5,400,826 show the use of inflatable balloons inside of pipes to stop the flow of fluid in the pipe.
U.S. Pat. No. 1,636,243 shows the use of an inflatable balloon to press a pad against the interior of a pipe joint to prevent sealant, which is being applied to the exterior of the pipe joint, from leaking into the pipe.
A satisfactory method or means for effectively ascertaining the contamination of an inner pipe surface while fluids are flowing normally through it appears not to be disclosed in the prior art.
SUMMARY OF THE INVENTION
The present invention, in one aspect, provides an novel method of obtaining surface samples from the inner surface of a pipe main through which a fluid is flowing. According to this novel method, an opening is provided in the pipe main. There is also provided an inflatable balloon-like element with a swab affixed to its outer surface. The balloon-like element is inserted, in deflated and collapsed condition and with the swab affixed thereto, through the opening in the pipe main and into the interior of the pipe main. Then the balloon-like element is caused to inflate and expand inside the pipe main to extend the swab into a generally planar configuration and to press the swab against an inner surface of the pipe main. Thereafter, the balloon-like element is deflated and collapsed; and the collapsed balloon-like element with the swab attached, is removed from the interior of the pipe main.
In another aspect the invention involves a novel apparatus for use in obtaining samples of contaminants from the inner surface of a pipe main. This novel apparatus comprises a first pipe which is constructed and arranged to be connected to a pipe main so that one end of the first pipe opens into the interior of the pipe main while its other end extends outside of the pipe main. There is also provided a second pipe having attached at one end thereof, a balloon-like element made of a flexible material and which can be inflated by application of fluid pressure through the second pipe. A swab is attached to the balloon-like element so that when the balloon-like element is inflated, the swab extends generally in a plane. When the balloon-like element is deflated, it collapses, together with the swab; and in this condition the balloon-like element and the swab may be pushed by means of the second pipe, through the first pipe and into the interior of a pipe main. Means are provided for applying fluid pressure through the second pipe to inflate the balloon-like element inside the pipe main so that it presses said swab against the interior surface of the pipe main, whereby material from the interior surface adheres to said the swab. Means are provided for thereafter releasing the fluid pressure to deflate and collapse the balloon-like element and the swab so that they can be withdrawn together from the interior of the pipe main through the first pipe.
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Brooklyn Union
Fitzpatrick ,Cella, Harper & Scinto
Noland Thomas P.
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