GB2091853A - Fluid control valve - Google Patents

Abstract

A fluid flow control valve comprises a deformable throughflow valve chamber 2 containing an obturating element 41 and means operative upon the exterior of said valve chamber for controllably deforming the wall of said chamber to vary the cross-sectional dimension of the chamber in the region of the obturating element, thereby to vary the fluid flow path therepast. The obturator 2 is retained in position by spiders 3. <IMAGE>

Description

SPECIFICATION Fluid control valve This invention concerns fluid flow control valves and has for its object the provision of a simple and reliable valve that may be cheaply fabricated and serve for controlling flows of fluids in automated laboratory and like processes, although as will appear the valve of the invention could be adapted to other applications.

In accordance with the invention, a fluid flow control valve comprises a deformable throughflow valve chamber containing an obturating element, and means operative upon the exterior of said valve chamber for controllably deforming said chamber to vary the cross-sectional dimension thereof in the region of said obturating element, thereby to vary the fluid flow path therepast.

The obturating element may have any suitable configuration, being conveniently a body of revolution, for instance a spherical body.

The valve chamber may conveniently be constituted by a portion of the length of a deformable fluid flow line.

Obturating element retainer means may be provided within the valve chamber for locating the obturating element against displacement therein.

For instance, stop rings or spiders may be secured in the valve chamber respectively upstream and downstream of the obturating element to restrict the movement of the latter with or contrary to the fluid flow direction through the chamber.

The means for varying the cross-sectional dimension of the valve chamber in the region of the obturating element may take any suitable form and may be mechanical in nature. However in preferred embodiments of the invention such means provide for the variation of fluid pressure external to the valve chamber to cause expansion and/or contraction thereof in the region of the obturating element.

Thus in a preferred embodiment of the invention the valve chamber is enclosed by a pressure chamber within which fluid pressure may be varied.

The pressure chamber may have an internal configuration adapted to prevent excessive deformation of the valve chamber. For instance, if the valve chamber is, as preferred, constituted by a portion of the length of a deformable fluid flow line having a natural cross section dimensionally less than that of the obturating element so that expansion of the valve chamber, by reducing pressure in the pressure chamber, is effective to open the flow path through the valve, the pressure chamber may be internally shaped to prevent over-expansion of the valve chamber. Conveniently the pressure chamber includes a rigid sleeve circumscribing the valve chamber. Such an arrangement would also serve to prevent over-expansion of the valve chamber if this were subjected to high internal pressure.

Atypical embodiment of the invention is illustrated in the accompanying drawing in which: Figure 1 is a pictorial illustration of a fluid flow control valve embodying the invention; Figure 2 is a part-sectional fragmentary view of the valve of Figure 1; Figure 3 is a cross-sectional view taken on the line Ill-Ill of Figure 2; Figure 4 is a pictorial view on an enlarged scale of an obturating element retainer incorporated in the valve of Figures 1 and 2; and Figure 5 is an enlarged sectional elevation of a sealing detail of the pressure chamber of the valve.

The illustrated valve is intended to control the flow of a processing fluid, e.g. from a source such as a gravity tank to a receptacle or other point of use of that fluid. A typical application of the valve would be in controlling the flow of a tissue processing fluid from a source to a container in which a histological or like tissue specimen is suspended for immersion in the processing fluid in the course of an automated tissue processing procedure.

The illustrated valve thus comprises a fluid flow line 1 that in this instance is conveniently of rubber or plastics material such as "Viton silicone", part of the length of which is formed into a simple valve chamber 2 by the fitment to the bore of the line of a pair of ball retainers 3 with interposed spherical obturating element 4.

The ball retainers 3 are spider-like plsstics mouldings of the configuration shown in Figure 4 with an external toroidal surface with an outer diameter sufficiently larger than the nominal bore diameter of the fluid line 1 so as to be retained in position by the natural resilience and accommodating deformation of the line 1 when fitted in place therein.

The obturating element 4 is preferably of a hard material such as glass or metal and, as shown, has a diameter significantly larger than the nominal bore diameter of the line 1 so as, normally, to block fluid flow through the line 1 by entirely obturating the bore thereof with an effective seal against the bore wall.

The valve chamber-constituting portion of the line 1 is enclosed within a pressure chamber formed conveniently as a pair of identical plastics or like relatively rigid hemispheres 5 each formed initially with a blind spigot 6. Each hemisphere 5 has a polar aperture formed with a lip seal-like annular projection 7 adapted, as shown in Figure 2, to engage the outerwall of the fluid line 1 in a manner to form a fluid seal thereabout.

The two hemispheres 5 are united in suitable manner as by adhesive bonding along their equatorial meeting planes.

One of the spigots 6 is made open upon assembly of the valve components to provide a patent connection to the interior of the pressure chamber.

The embodiment of the valve of the invention is intended to be operated by the application of reduced pressure (vacuum) to the interior of the pressure chamber thereby to cause expansion of the valve chamber-constituting portion of the fluid line 1 housing the obturating element 4, to an extent sufficient to provide a flow path for fluid around the element 4. Thus a suitable vacuum source may be connected to the opened spigot 6 via a convenient pneumatic logic control unit.

Figures 2 and 3 show an optional rigid sleeve 8 that can be provided in each of the hemispheres 5.

The sleeves 8 are axially aligned with the flow line 1 and, when the hemispheres are united, form a non-continuous pathway through which the flow line 1 passes, the diameter of the passage being such that the flow line 1 cannot expand beyond a prescribed limit. The non-continuous nature of the pathway ensures that the provision of sleeves 8 does not interfere with the efficient operation of the valve.

The sleeves 8 may be of the same rigid material as the hemispheres 5 and may be formed integrally with and in the same moulding process as the hemispheres.

This illustrated valve is thus intended to function as a normally-closed on/off valve the opening of which is effected by the application of control (vacuum) pressure to the pressure chamber. However it should be understood that by modifying the valve so as to have an obturating element smaller than the nominal bore diameter of the fluid line portion constituting the valve chamber a normallyopen on/off valve construction would be obtained, the valve being closeable by the application of suitable positive fluid pressure to the pressure chamber. Particularly in the latter case the operating pressure fluid could be hydraulic ratherthan gaseous.

It will be apparent that the valve may be constructed with fluid-contacting components - the fluid line 1, the ball retainers 2 and the obturating element 3 - of materials suited to contact with the fluid to be controlled by the valve. Moreover the valve is suited to the control of fluids containing solids, such as slurries or suspensions.

The valve of the invention may of course be used for the control of flammable or like hazardous fluids because it involves no seals or glands through which such a fluid could escape and also because in preferred embodiments, such as that illustrated, the control of the valve is effected by fluid pressure that in turn may be controlled from a remote location.

It will also be apparent that, given appropriate choice of materials of construction for the fluidcontacting parts, there can be no contamination of the controlled fluid by the valve or its control arrangements.

For these reasons the valve of the invention is particularly applicable to the automation of laboratory procedures and to medical and biological uses as in the control of body fluids in surgical and therapeutic procedures. The simple constructional form of the valve allows for low cost manufacture of disposable valve units requiring no maintanance throughout an intended working life span.

Claims (11)

1. Afluid flow control valve comprising a deformable throughflow valve chamber containing an obturating element, and means operative upon the exterior of said valve chamber for controllably deforming said chamber to vary the cross-sectional dimension thereof in the region of said obturating element, thereby to vary the fluid flowpath therepast.

2. A fluid flow control valve according to claim 1, in which the obturating element comprises a spherical body.

3. A fluid flow control valve according to claim 1 or 2, in which the valve chamber is constituted by a portion of the length of a deformable fluid flow line.

4. A fluid flow control valve according to claim 1, 2 or 3, including obturating element retainer means within the valve chamber for locating the obturating element against displacement therein.

5. A fluid flow control valve according to claim 4, in which said retainer means comprise stop rings or spiders secured in the valve chamber respectively upstream and downstream of the obturating element.

6. Afluid flow control valve according to any one ofthe preceding claims, including a pressure cham berthat encloses the valve chamber.

7. A fluid flow control valve according to claim 6, wherein said pressure chamber has an internal configuration adapted to prevent excessive deformation of the valve chamber.

8. Afluid flow control valve according to claim 6 or 7, in which said obturating element has a diameter significantly largerthan the nominal bore diameter of said valve chamber to close the flowpath through the valve chamber except when pressure in said pressure chamber is reduced so as to cause expansion of the valve chamber in the region of the obturating element.

9. A fluid flow control valve according to claims 7 and 8, wherein said pressure chamber includes a rigid sleeve circumscribing the valve chamber.

10. A fluid flow control valve substantially as described with reference to, and as shown in, the accompanying drawings.

11. Every novel feature and every novel combination of features disclosed herein.