Method of forming a flow restrictor
First Claim
1. A method of forming a flow restrictor which comprises positioning a thin, elongate member within a flexible tube, flattening the tube about the member to bring internal wall surfaces of the tube into contact with each other at each lateral side of the member, permanently securing the contacting wall surfaces to each other at each lateral side of the member but over only a part of the area of the internal wall surface of the tube on at least one lateral side of the member and removing the member to leave a flow passage of a cross-section defined by that of the member, and the unsecured part of the internal wall surface of the tube defining a bypass in parallel with the flow passage.
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Accused Products
Abstract
A flow restrictor is made by flattening a tube of flexible material about a member of cross-sectional characteristics representative of a desired flow passage, and securing the tube there, e.g. by rf welding. The member is then removed leaving a determinate flow passage in which problems of creep do not arise. The restrictor may have parallel to the flow passage a portion of the tube which is not permanently secured together so as to leave a by-pass which can be open to give a comparatively unrestricted flow passage or can be temporarily completely closed by external compression. A single tube may have in line a plurality of such restrictors with by-passes, the flow passages of the various restrictors being of different flow characteristics. The flow characteristic required is obtained by closing off the by-pass associated with the selected flow passage.
31 Citations
6 Claims
- 1. A method of forming a flow restrictor which comprises positioning a thin, elongate member within a flexible tube, flattening the tube about the member to bring internal wall surfaces of the tube into contact with each other at each lateral side of the member, permanently securing the contacting wall surfaces to each other at each lateral side of the member but over only a part of the area of the internal wall surface of the tube on at least one lateral side of the member and removing the member to leave a flow passage of a cross-section defined by that of the member, and the unsecured part of the internal wall surface of the tube defining a bypass in parallel with the flow passage.
Specification