Patent EP0034671A1 successfully refreshed from Google Patents.
EP0034671A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus, especially an intravenous infusion set, for maintaining a desired rate of fluid flow
Assignee: University of Exeter
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Filing: 1980-02-18
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Granted: —
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Expires: 2000-02-18
Abstract
Abstract Fluid flow rate is controlled by passing it through a collapsible conduit (22) and arranging that the pressure head driving the fluid through the fluid path downstream of the collapsible conduit is sufficiently smaller than the pressure head driving the fluid through the collapsible conduit that the conduit is maintained in a partially collapsed condition. This decouples the upstream and downstream parts of the path and prevents downstream pressure variations being propagated to the upstream part. Variations in the upstream pressure head, e.g. in a supply reservoir (10), can be compensated by transmitting those pressure variations also to an enclosure (24) around the collapsible conduit, thereby keeping the transmural pressure difference constant. An adjustable height chamber (30), partially filled with liquid, in the pressure compensation transmission path enables the flow rate to be varied. The invention is particularly applicable to intravenous infusion sets for controlling the infusion rate.
Inventors
- 👤 Derek John Griffiths
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 16:31
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/16804; A61M5/16818; F; F16; F16K; F16K7/00; F16K7/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
98 words
A method of maintaining a desired rate of fluid flow, characterised in that the fluid (12) is passed along a path which includes a collapsible conduit (22) which can vary readily in internal cross-section according to variations in the transmural pressure difference,and arranging that the pressure head driving the fluid (12) through the fluid path downstream of the collapsible conduit is sufficiently smaller than the pressure head driving the fluid through the collapsible conduit, that the collapsible conduit is partially collapsed and mean fluid pressure variations in the downstream path are not propagated upstream of the collapsible conduit.
Claim 2
Independent Claim
98 words
A method of maintaining a desired rate of fluid flow, characterised in that the fluid (12) is passed along a path which includes a collapsible conduit (22) which can vary readily in internal cross-section according to variations in the transmural pressure difference,and arranging that the pressure head driving the fluid (12) through the fluid path downstream of the collapsible conduit is sufficiently smaller than the pressure head driving the fluid through the collapsible conduit, that the collapsible conduit is partially collapsed and mean fluid pressure variations in the downstream path are not propagated upstream of the collapsible conduit.
Claim 3
Dependent Claim
35 words
A method according to claim 1 wherein an enclosure (24) is provided surrounding the collapsible conduit, the internal cross-section of the conduit being controlled by the action of external fluid pressure applied to the enclosure.
Claim 4
Dependent Claim
88 words
A method according to claim 2 for maintaining a rate of liquid flow, wherein the collapsible conduit is connected to a reservoir (10) for the liquid, an inlet (26) to the enclosure (24) being connected with a conduit in fluid pressure transfer connection with the liquid in the reservoir (10), whereby variations in the pressure head of the liquid in the reservoir are transmitted as corresponding variations in pressure applied to the collapsible conduit, tending to maintain a constant rate of flow of liquid through the collapsible conduit.
Claim 5
Dependent Claim
101 words
A method according to claim 3 wherein a chamber (30) is provided in said fluid pressure transfer conduit between the liquid reservoir (10) and the inlet (26) to the enclosure, the chamber having a lower port (32) for liquid leading from the reservoir and an upper port (28) for gas leading to the enclosure, whereby gas pressure in the enclosure varies with the difference in the level of liquid in the reservoir (10) and that in the chamber.(30), the height of the chamber (30) preferably being adjustable relative to the reservoir for setting the liquid flow rate through the collapsible conduit.
Claim 6
Independent Claim
133 words
A method according to any one of the preceding claims wherein the collapsible conduit comprises a flexible sleeve (22) surrounding a rigid insert (34), the internal circumference of the sleeve in cross-section being substantially the same as the external circumference of the cross-section of the insert which it surrounds, the insert having an inlet (38) leading to an internal passage for the fluid and a lateral outlet (42) therefrom intermediate the ends of the insert and covered by the sleeve, a longitudinal surface of a portion (36) of the insert from the region of said outlet being concave in cross-section to provide a channel (44) under the sleeve for the escape of fluid when the pressure of fluid issuing from said outlet (42) urges the sleeve away from that portion of the insert.
Claim 7
Dependent Claim
110 words
A method according to claim 5 including any one or more of the following features, namely: (a) the sleeve (22) is of elastomeric material; (b) the transverse cross-section of the channel (44) in the portion (36) of the insert (34) increases in the direction away from said outlet (42); (c) the insert (34) is of generally flat shape over at least the fluid escape portion (36 ) extending from said outlet (42), the concavity (44) being formed in one of the faces of the flat part of the insert; (d) the fluid inlet (38) to the insert is situated at the end thereof remote from the concave surface portion (44).
Claim 8
Independent Claim
81 words
A method according to any one of claims 1 to 4 wherein the collapsible conduit (22) comprises a flexible tube (Figs. 11 and 12) which can itself collapse to substantially zero internal cross-section; the flexible tube preferably comprising two flat layers of flexible material sealed together face-to-face along opposite longitudinal edges (19), the two layers being separate layers of flexible material or opposite surfaces of a flattened tube which has been subjected to a sealing process along its opposite edges (19).
Claim 9
Dependent Claim
71 words
An intravenous infusion set adapted for maintaining a desired rate of liquid flow by a method according to any one of claims 1 to 7, the set comprising a first tube (33) for connection to a giving bag or bottle, a second tube (21) for connection to a hypodermic needle, and a drip chamber (20) and a said collapsible conduit (22) located in the liquid path between the two tubes (21,33).
Claim 10
Dependent Claim
202 words
Apparatus for maintaining a desired liquid flow rate by a method according to claim 3, the apparatus including a collapsible conduit (22), a tube connecting the collapsible conduit to a reservoir (10) of the liquid, an enclosure (24) surrounding the collapsible conduit, the enclosure having inlet means (26) for the communication thereto of externally applied fluid pressure, whereby the internal cross-section of the conduit (22) can be controlled by the action of externally applied fluid pressure, the inlet to the enclosure being connected with a conduit in fluid pressure transfer connection with said reservoir (10), whereby variations of the pressure head of the liquid in the reservoir are transmitted as corresponding variations in pressure applied both internally and externally to the , collapsible conduit (10) tending to maintain a constant rate of flow of liquid through the collapsible conduit; optionally a chamber (30) being provided in said fluid pressure transfer conduit, the chamber having a lower port (32) for liquid leading from the reservoir (10) and an upper port (28) for gas leading to the enclosure (24), whereby gas pressure in the enclosure varies with the difference in the level of liquid in the reservoir (10) and that in the chamber (30).
Claim 11
Dependent Claim
144 words
Apparatus for maintaining a desired liquid flow rate by a method according to claim 5 or claim 6, including a collapsible conduit comprising a flexible sleeve (22) surrounding a rigid insert (34), the internal circumference of the sleeve in cross-section being substantially the same as the external circumference of the cross-section of the insert which it surrounds, the insert having an inlet (38) leading to an internal passage for the fluid and a lateral outlet (42) therefrom intermediate the ends of the insert and covered by the j sleeve (22), a longitudinal surface of the portion (36) of the insert from the region of said outlet (42) being concave in cross-section to provide a channel (44) under the sleeve for the escape of fluid when the pressure of fluid issuing from said outlet (42) urges the sleeve away from that portion of the insert.
References Cited (Backward Citations)
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Cited
US2786642A
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US2766765A
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GB1467946A
Cited
US4043332A
Cited
US4186740A
Cited
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