Nonreturn valve for medical fluid technologies

• US 5,617,897 A
• Filed: 02/16/1994
• Issued: 04/08/1997
• Est. Priority Date: 02/18/1993
• Status: Expired due to Term

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Schawk Incorporated (Matthews International Corporation)
• Inventors: Myers, Jan W. M.
• Primary Examiner(s): Michalsky, Gerald A.
• Application Number:
  US08/197,999
• Time in Patent Office: 1,147 Days
• Field of Search: 137/859, 604/247
• US Class Current: 137/859
• CPC Class Codes: A61M 2039/242 designed to open when a predetermined pressure or flow rate has been reached, e.g. check valve actuated by fluid
• CPC Class Codes: A61M 2039/2433 Valve comprising a resilient or deformable element, e.g. flap valve, deformable disc
• CPC Class Codes: A61M 2039/246 being fixed along all or a part of its periphery
• CPC Class Codes: A61M 39/24 Check- or non-return valves
• CPC Class Codes: F16K 15/144 the closure elements being fixed along all or a part of their periphery

Abstract

A nonreturn valve for use in controlling the flow of medical fluid. The valve has two mating valve shells which carry and communicate with first and second pipe connectors, respectively. A diaphragm with a protrusion on its periphery is held between the valve shells. Circumferentially disposed retaining formations on each of the valve shells causes pretension to occur in the diaphragm upon assembly of the valve shells. The axial location of the retaining formation on the valve shell which carries the valve seat is such that tension in the diaphragm lightly urges the diaphragm into sealing engagement with the valve seat, whereby a seal exists when there is no significant pressure on either side of the diaphragm.

Claims

1. A nonreturn valve, particularly for medical fluid technology applications, comprising a first pipe connector defining an inlet and having a sealing seat, and a second pipe connector defining an outlet, and a diaphragm made of a flexible material, which is located between said pipe connectors and which can be lifted from said sealing seat upon overpressure in said inlet, thus creating a flow opening, said diaphragm capable of being pressed against said sealing seat upon overpressure in said outlet, the diaphragm having a central section and an outer section with a bulge on its periphery, a first valve shell of the first pipe connector and a second valve shell of the second pipe connector forming a cavity housing the bulge but leaving an opening for said diaphragm, one wall surface of the cavity pointing radially outwardly and being adjacent to said bulge such that tensile forces are created in the diaphragm upon assembly of both valve shells, each of said valve shells having an inner and an outer annular protrusion, said outer protrusions fitting closely within each other and providing means for said valve to be assembled, at least one of said valve shells having a slanted wall surface on its inner annular protrusion which abuts an opposing inwardly facing surface of said bulge, said slanted surface of said valve shell being circumferentially continuous and slanting at a slope which is approximately the same as the slope of said inwardly facing surface of said bulge, said bulge having rounded surfaces defining a generally ovoid cross-section, the first valve shell of the first pipe connector having an annular sealing lip, and the second valve shell having several stroke limiting nubs opposite the sealing lip, with the sealing lip located inside inner edges of openings in the diaphragm, said inner annular protrusions being rounded in cross-section, one of said valve shells having a base which carries said lip and a first one of said inner annular protrusions, said first inner protrusion extending from said base an axial extent which is less than the extent to which said lip extends from said base.

2. A nonreturn valve according to claim 1 wherein:

said tensile forces and assembly of said valve shells cause said diaphragm to be urged against said sealing lip.

3. A nonreturn valve according to claim 2 wherein:

said sealing lip has a sharp edge formed by two intersecting frustoconical surfaces, said surfaces defining an included angle of about 40°

, whereby the pressure exerted by said lip upon said diaphragm is increased.

4. A nonreturn valve for medical and fluid technology applications comprising a first pipe connector and a second pipe connector between which a membrane disc made of a flexible material is held lifted from a sealing seat upon overpressure in the inlet, and which requires minimum time for being pressed safely against the sealing seat upon overpressure in the outlet, the central part of the membrane disc being predominantly uniform in thickness, the outer circumferential section of the membrane disc having an annular bulge, a first shell of the first pipe connector and second shell of the second pipe connector forming a hollow space which surrounds the bulge except for a gap of approximately the same size as the thickness of the central part of the membrane disc, at least one surface of the hollow space facing outwardly pressing against the protrusion in such a way that, upon assembly of both shells, radially oriented tensile forces can be induced in the membrane disc, said at least one surface having a slope, the bulge having a rounded cross-sectional profile, and the radially outward facing surface forming part of an annual recess on the associated shell, the first shell of the first pipe connector having an annular sealing lip, the second shell having a plurality of stroke limiting knobs distributed within said second shell located opposite the sealing lip, said membrane disc having openings therethrough, and the sealing lip having a radial extent such that said lip engages said membrane disc at locations which are disposed radially inwardly of said openings.

5. A nonreturn valve according to claim 4 characterized by the feature that the sealing lip protrudes in a radial plane with respect to the annular protrusion.

6. A nonreturn valve according to claim 4 wherein:

said shells are connected to each other by an inner annular rim formed on one of said shells, and an outer annular rim formed on the other of said shells, with said annular rims having close-fitting dimensions.