Pipe inspection method and device

• US 4,866,978 A
• Filed: 08/17/1988
• Issued: 09/19/1989
• Est. Priority Date: 08/17/1988
• Status: Expired due to Term

• Current Assignee: Bruce A. Biggerstaff
• Original Assignee: Bruce A. Biggerstaff
• Inventors: Biggerstaff, Bruce A.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Simons, Michele
• Application Number:
  US07/233,249
• Time in Patent Office: 398 Days
• Field of Search: 73/865.8, 73/40.5 R, 73/866.5, 33/1 H, 33/302, 33/304, 33/178 F, 33/544
• US Class Current: 73/865.8
• CPC Class Codes: G01B 5/12 internal diameters
• CPC Class Codes: G01B 5/207 using a plurality of fixed, simultaneously operating transducers G01B5/213 - G01B5/22 take precedence

Abstract

A method and device for inspecting the internal cross-sectional shape of pipes, and particularly of sewer pipes. A mandrel is inserted into the pipe. The mandrel may include an elastomeric member providing a fluid seal engaging the internal pipe surface. The mandrel also has a retrieval chord attached thereto and trailing therebehind. A plug member is provided behind the mandrel, which may be inflatably expanded to define a second fluid seal with the pipe. The space between the pipe and the two fluid seals is pressurized, such as with compressed air, causing the mandrel to advance along the pipe, pulling the retrieval chord as it advances. The mandrel'"'"'s advancement will be stopped by a sufficiently large deformation. Thereafter, the mandrel is retrieved by pulling on the retrieval chord.

Claims

1. A method for inspecting the internal cross-sectional shape of pipes comprising the steps of:

inserting a mandrel into a sewer pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface, said mandrel having a retrieval cord attached thereto and trailing behind said mandrel, wherein said mandrel includes a plurality of circumferentially disposed arm members and an elastomeric diaphragm forming said first means for providing a fluid seal;

fixing in a sewer pipe a plug member in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween; and

propelling said mandrel along the pipe by pressurizing said pressurizing space with a fluid, wherein said retrieval cord trails behind said mandrel during said propelling step.

2. The method of claim 1 wherein said inserting step and said fixing step occur in a sewer pipe located in a sewer manhole.

3. The method of claim 2 and further comprising the step of retrieving said mandrel from within the pipe by pulling on said retrieval cord toward said plug member, said retrieving step occurring after said propelling step.

6. The method of claim 1 and further comprising the step of retrieving said mandrel from within the pipe by pulling on said retrieval cord toward said plug member, said retrieving step occurring after said propelling step.

8. The method of claim 1 wherein said plug member has a central opening therein located along a central axis of said plug member, and wherein said propelling step includes the step of forcing compressed air through said central opening, wherein said mandrel comprises a rigid cage with an elastomeric diaphragm thereon forming said first means for providing a fluid seal, and wherein said retrieval cord feeds through said central opening in said plug member as said mandrel is propelled away from said plug member.

4. A method for inspecting the internal cross-sectional shape of pipes comprising the steps of:

inserting a mandrel into a pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface, said mandrel having a retrieval cord attached thereto and trailing behind said mandrel;

fixing a plug member in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween;

propelling said mandrel along the pipe away from said plug member by pressurizing said pressurizing space with a fluid, wherein said retrieval cord trails behind said mandrel during said propelling step;

wherein said inserting step and said fixing step occur in a sewer pipe located in a sewer manhole;

retrieving said mandrel from within the pipe by pulling on said retrieval cord toward said plug member, said retrieving step occurring after said propelling step; and

wherein said fixing step includes the step of inflating an inflatable expanding vessel within the pipe forming said second means for providing a fluid seal.

5. The method of claim 4 wherein said plug member has a central opening therein located along a control axis of said plug member, and wherein said propelling step includes the step of forcing compressed air through said central opening, wherein said mandrel comprises a rigid cage with an elastomeric diaphragm thereon forming said first means for providing a fluid seal, and wherein said retrieval cord feeds through said central opening in said plug member as said mandrel is propelled away from said plug member.

7. A method for inspecting the internal cross-sectional shape of pipes comprising the steps of:

inserting a mandrel into a pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface, said mandrel having a retrieval cord attached thereto and trailing behind said mandrel;

fixing a plug member in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween;

propelling said mandrel along the pipe by pressurizing said pressurizing space with a fluid, wherein said retrieval cord trails behind said mandrel during said propelling step; and

wherein said fixing step includes the step of inflating an inflatable expanding vessel within the pipe forming said second means for providing a fluid seal.

9. A method for inspecting the internal cross-sectional shape of pipes comprising the steps of:

inserting a mandrel into a pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface, said mandrel having a retrieval cord attached thereto and trailing behind said mandrel;

fixing a plug member in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween;

propelling said mandrel along the pipe away from said plug member by pressurizing said pressurizing space with a fluid, wherein said retrieval cord trails behind said mandrel during said propelling step;

retrieving said mandrel from within the pipe by pulling on said retrieval cord toward said plug member, said retrieving step occurring after said propelling step; and

wherein said fixing step includes the step of inflating an inflatable expanding vessel within the pipe forming said second means for providing a fluid seal.

10. A device for inspecting the internal cross-sectional shape of pipes comprising:

a mandrel adapted to be inserted into a sewer pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface, wherein said mandrel includes a plurality of circumferentially disposed arm members and an elastomeric diaphragm forming said first means for providing a fluid seal;

a retrieval cord attached to said mandrel and adapted to trail behind said mandrel;

a plug member adapted to be fixed in the sewer pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween; and

means for pressurizing said pressurizing space, wherein said mandrel is propellable along the pipe away from said plug member with said first means for providing a fluid seal being freely movable along the internal pipe surface upon pressuring said pressuring space, and wherein said retrieval cord trails behind said mandrel between said mandrel and said plug member.

11. A device for inspecting the internal cross-sectional shape of pipes comprising:

a mandrel adapted to be inserted into a pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface;

a retrieval cord attached to said mandrel and adapted to trail behind said mandrel;

a plug member adapted to be fixed in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween;

means for pressurizing said pressurizing space, wherein said mandrel is propellable along the pipe away from said plug member with said first means for providing a fluid seal being freely movable along the internal pipe surface upon pressuring said pressuring space, and wherein said retrieval cord trails behind said mandrel between said mandrel and said plug member; and

wherein said means for pressuring comprises an air compressor, and wherein said plug member includes an inflatable expanding vessel for inflation within the pipe forming said second means for providing a fluid seal.

12. A device for inspecting the internal cross-sectional shape of pipes comprising:

a mandrel adapted to be inserted into a pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface;

a retrieval cord attached to said mandrel and adapted to trail behind said mandrel;

a plug member adapted to be fixed in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween;

means for pressurizing said pressurizing space, wherein said mandrel is propellable along the pipe away from said plug member with said first means for providing a fluid seal being freely movable along the internal pipe surface upon pressuring said pressuring space, and wherein said retrieval cord trails behind said mandrel between said mandrel and said plug member;

wherein said means for pressuring comprises an air compressor, and wherein said plug member includes an inflatable expanding vessel for inflation within the pipe forming said second means for providing a fluid seal; and

wherein said air compressor is coupled to said pressurizing space and to said inflatable expanding vessel by a common pressure line, said pressure line having a first valved branch coupled to said pressuring space and further having a second valved branch coupled to said inflatable expanding vessel.

13. The device of claim 12 wherein said mandrel comprises a rigid cage with an elastomeric diaphragm thereon forming said first means for providing a fluid seal.

14. A device for inspecting the internal cross-sectional shape of pipes comprising:

a mandrel adapted to be inserted into a pipe having an internal pipe surface, said mandrel having first means for providing a fluid seal engaging the internal pipe surface;

a retrieval cord attached to said mandrel and adapted to trail behind said mandrel;

a plug member adapted to be fixed in the pipe behind said mandrel, said plug member having second means for providing a fluid seal with the pipe, wherein said first means for providing a fluid seal, said second means for providing a fluid seal and the internal pipe surface collectively define a pressuring space therebetween;

means for pressurizing said pressurizing space, wherein said mandrel is propellable along the pipe with said first means for providing a fluid seal being freely movable along the internal pipe surface upon pressuring said pressuring space, and wherein said retrieval cord trails behind said mandrel between said mandrel and said plug member; and

wherein said mandrel comprises a rigid cage with an elastomeric diaphragm thereon forming said first means for providing a fluid seal.