The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 11, 1988
Filed:
Apr. 23, 1987
John Dimeff, San Jose, CA (US);
Mark Telephone Products, Santa Clara, CA (US);
Abstract
An improvement in the test for air leaks of an air pressurized telephone cable is disclosed. The cable is of the type wherein a number of individually insulated conducting electrical strands are surrounded by a protective plastic tubing impermeable to water and maintained dry under air pressure. The cable is typically buried. The improvement comprises a capillary flow controller for the introduction of trace gas, such as helium into the cable. The trace gas is introduced into the system at a pressure exceeding twice and preferably 10 times the ambient dry air pressure within the cable. The capillary introduces the high pressure trace gas to the interior of the cable by leaking a relatively constant volume flow rate to a discharge chamber. The discharge chamber includes a pressure relief valve--to guard against cable sheath rupture in the case of local occlusion, a pressure gauge--to measure the pressure of the line at the point of helium introduction, and a discharge aperture--which is the point of introduction of the trace gas into the air pressurized cable. Trace gas enters into the system through the capillary at a constant rate which can from time to time be monitored with conventional flow rate equipment.