Blown installation of optical fibres and method and apparatus for determining the length of a passage along which an optical fibre is to be blown
First Claim
1. A method of determining a length Lt at least representative of the length of a tube that defines a passage in an optical fibre cable along which an optical fibre unit can be installed by blowing, said method comprising the steps of providing a first volume V1 containing a gas at a first pressure P1, releasing said gas into a second volume V2 that comprises said passage, determining a second gas pressure P2 in said second volume V2 after release of said gas from said first volume, determining said second volume V2 by reference to said first pressure P1, second pressure P2 and said first volume V1 and determining said length Lt by reference to said second volume V2.
2 Assignments
0 Petitions
Accused Products
Abstract
An apparatus (12) is provided for use in determining a length at least representative of the length of a tube that defines a passage in an optical fibre cable (10) along which an optical fibre unit can be installed by blowing. The apparatus (12) comprises a pressure reservoir (32) in which a gas at a known pressure can be stored, outlet piping (34) connected with the pressure reservoir (32) and having an outlet end spaced from the reservoir for connection to a tube of the optical fibre cable (10). The apparatus has a pressure detecting arrangement (42) for detecting gas pressure in a tube connected with the outlet end of the outlet piping (34). In use, the gas stored in the pressure reservoir (32) is released into the tube and knowing the pressure of the gas when stored in the pressure reservoir, the volume of the reservoir and the pressure of gas in the tube after release of the gas from the pressure reservoir, it is possible to determine the volume of the passage defined by the tube and knowing that volume, it is possible to determine the length of the tube.
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Citations
28 Claims
- 1. A method of determining a length Lt at least representative of the length of a tube that defines a passage in an optical fibre cable along which an optical fibre unit can be installed by blowing, said method comprising the steps of providing a first volume V1 containing a gas at a first pressure P1, releasing said gas into a second volume V2 that comprises said passage, determining a second gas pressure P2 in said second volume V2 after release of said gas from said first volume, determining said second volume V2 by reference to said first pressure P1, second pressure P2 and said first volume V1 and determining said length Lt by reference to said second volume V2.
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10. A method of determining a length at least representative of the length of a tube in an optical fibre cable along which an optical fibre unit can be installed by blowing, the optical fibre cable having a first end and a second end and comprising sheathing housing at least one said tube and the method comprising:
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connecting a pressure reservoir having a known volume with the or one said tube at said first end of the optical fibre cable;
providing sealing at said second end of the optical fibre cable such that an end of said tube connected to the pressure reservoir is sealed at said second end of the optical fibre cable;
releasing a gas at a known pressure from said pressure reservoir into said tube connected with said pressure reservoir;
determining a pressure of the gas that is in said tube connected with said pressure reservoir after said release of gas;
determining the volume of said tube connected with said pressure reservoir by reference to said known volume, known pressure and determined pressure; and
determining a length at least representative of the length of said tube connected with said pressure reservoir by reference to said volume thereof and an inside diameter thereof. - View Dependent Claims (11, 12, 13, 14)
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- 16. Optical fibre cable length determining apparatus for use in determining a length at least representative of the length of a tube that defines a passage in an optical fibre cable along which an optical fibre unit can be installed by blowing, said apparatus comprising a pressure reservoir in which a gas at a known pressure can be stored, outlet piping connected with said pressure reservoir and having an outlet end spaced from said reservoir for connection to said tube and a pressure detecting arrangement for detecting gas pressure in said tube connected with said outlet end.
- 27. A method of determining a length Lt at least representative of the length of a passage along which an optical fibre unit can be installed by blowing, said method comprising the steps of providing a first volume V1 containing a gas at a first pressure P1, releasing said gas into a second volume V2 that comprises said passage, determining a second gas pressure P2 in said second volume V2 after release of said gas from said first volume, determining said second volume V2 by reference to said first pressure P1, second pressure P2 and said first volume V1 and determining said length Lt by reference to said second volume V2.
Specification