GB2045901A - Disk-type check valve - Google Patents

Abstract

The check valve has a compact body formed by joining two complementary monoblock fluid-handling sections (12, 14) together to form a fluid tight annular seal surrounding a valve chamber (26) in which there is loosely confined a disk-type valve member (8) having a ring seal (9) on its upstream side and biased toward the closed position in which said ring seal contacts an opposing uniform annular valve seat (13) by means of a stably supported biasing spring (28) bearing uniformly against the downstream side of said valve member. <IMAGE>

Description

SPECIFICATION Disk-type check valve This invention relates to simple, dependable disktype check valves with easy opening, low motion characteristics. The novel check valves disclosed herein capitalize upon an annular valve seat located outside of an ample fluid entry port to insure quick response even at low pressure differentials while providing high flow capacity at small axial displacement of the disk-type valve member. As a result said valves are simple and compact in both construction and operation. Since these valves are easily assembled from a limited number of simple parts and ele ments, the individual components may be fabricated from a variety of selected materials as required to meet particular service conditions, such as exposure to corrosive fluids and the like, and thus provide excellent operating durability.

Because of their active responsiveness and low pressure drop characteristics, the subject check valves are particularly suitable for applications involv ing low pressure fluid supply systems, including even those involving sub-atmospheric pressures.

Previously, reliable check valves with such perfor mance characteristics and structural features have not been readily available. Thus, the simplest and most dependable check valves of the prior art typi cally feature narrowly restricted seats and relatively constricted flow passages, such as those incorporat ing the well known ball- or poppet type valve mem bers. On the other hand, prior art check valves of higher flow capacity and large port openings have not generally proven sufficiently dependable or dur able and, except where some back-flow fluid leakage could be tolerated, have usually necessitated the use of auxiliary or back-up protection means such as supplementary diaphragms, secondary confinement zones and/or bleed-off devices.

The primary object of the present invention is to provide a responsive and dependable check valve with ample forward flow capacity and positive clos ing action for complete stoppage of back flow with out the use of complicated auxiliary protection means. A related object is the provision of such a valve of simple structural design featuring low motion valve member displacement so that it will be simple to construct and operate and will provide excellent service and long durability.

Another object is to provide a simple, compact check valve with generous flow capacity and rela tively low pressure drop effects so that it can be used efficiently even with low pressure fluid supply sys tems.

An additional objective is to fabricate such a check valve from a limited number of simple component parts which fit together readily in a neat assembly which can be dismantled quickly for convenient access to all individual parts, permitting economical replacement and maintenance. A related object is to maximize durability and optimize costs by exercis ing the highest degree of selectivity in choice of materials of construction and methods of fabrication for each individual component part.

Still other objects and advantages will become apparent from the more detailed description of the invention which follows.

The objects and advantages discussed above are achieved by constructing the check valve with a two piece body composed of a fluid supply head section and a fluid discharge tail section having complementary annular seats on opposing end faces thereof shaped to fit together closely and cooperative joining means (such as a series of connecting bolts) for drawing said sections together to form a fluid tight joint between said seats surrounding an enclosed valve chamber of uniform cylindrical shape, said head section having a fluid supply passageway through same communicating with the upstream end of said valve chamber through a central port with a surrounding end face having a uniform annular valve seat thereon.Completion of the valve assembly also entails the inclusion in said valve chamber of (1) a rigid, disk-shaped valve member the outer diameter of which provides ample annular clearance for fluid flow while assuring a loose coaxial alignment of same in said chamber, said member having a cooperation ring seal on its upstream side directly opposed to said valve seat, and (2) a substantially coaxial biasing spring mounted on said tail section and bearing against the downstream side of said valve member, said tail section having a fluid discharge passage leading through same from said valve chamber.

In providing the cooperating ring seal on the upstream side of the valve member, one technique which has helped to insure positive closing action at the valve seat makes use of an elastomeric O-ring.

Such an O-ring member can be incorporated in a suitable supporting groove in either the valve seat or the valve member provided one is available which is sufficientlytemperature resistant and inert to the fluid to be handled, and such incorporation has proven particularly advantageous in the operation of the present check valves at low pressures.

In order to provide a fuller understanding of the present invention and of certain important design variables and relationships which affect the operation and performance of the instant valves, several presently preferred embodiments and various optional features of particular significance in given situations will now be described in some detail.In presenting these detailed descriptions, reference is made to the accompanying drawings, wherein: FIG. 1 is a largely sectional view of a simplified check valve assembly taken along a vertical plane through the axis of the main valve chamber and the central entry port to same; FIG. 2 is an analogous sectional view of a similar basic unit modified somewhat to illustrate certain preferred optional features of this invention; FIG. 3 is a similar largely sectional view of a check valve assembly constructed in accordance with the present invention wherein a vacuum generating ejector unit has been integrated into the tail section of the unit; and FIG. 4 is a largely sectional view of another check valve assembly having provision for incorporating an ejector device like the one shown in FIG. 3 but with the sectional plane in FIG. 4 being normal to that of FIG. 3.

Referring first to FIG. 1, the complete valve body is composed of two complementary members, namely head section 12 and tail section 14, each of which is essentially a structural monobloc having a generally square-like configuration normal to the sectional view shown. Head section 12 is provided with internally threaded fluid inlet opening 22, while tail section 14 includes similarly threaded fluid outlet opening 24. Head section 12 and tail section 14 are also equipped with directly opposed annular seats 16 and 18 respectively and a set of matching bolt holes 20 and 20' located to the outside of said annular seats and near each ofthefourcorners. Bolts 19 and nuts 21 enable sections 12 and 14 to be drawn into sealing engagement after the valve assembly is complete.

Head section 12 is provided with fluid supply passageway 11 leading from inlet opening 22 to central valve port 10 in its downstream end face, which has uniform annular valve seat 13 formed thereon. Centrally recessed into the upstream end face of tail section 14 is main valve chamber 26 which communicates with outlet opening 24 through fluid passageway 25. The operative valve member is a simple disk 8 loosely confined in cylindrical valve member 26 and having on its upstream side, and directly opposed to valve seat 13 in a continuous annular band, the cooperating ring seal 9.Disk 8 is biased toward its closed position, i.e. with ring seal 9 in contact with the valve seat 13, by the action of compressed biasing spring 28 (shown unsectioned) mounted in tail section 14 in substantially coaxial alignment with chamber 26 so as to bear uniformly againstthe downstream side of disk 8.

Although the depth to which chamber 26 is recessed into tail section 14 will obviously depend upon many factors (including such obvious considerations as the required thickness of the disk used as the operative valve element and the volumetric flow capacity to be handled by the valve), a relatively shallow depth is generally desirable. In fact, it is usually preferred that the maximum axial displacement of the valve member disk 8 not greatly exceed that needed for fluid flow capacity and that the depth of chamber 26 be substantially less than its diameter, since both durability and dependability tend to improve as the axial displacement or motion is reduced while the flow capacity through a given annular clearance or slot width will increase directly with the diameter.

Furthermore, since the diameters of related valve parts such as the valve seats will tend to increase proportionately also, additional advantages can ensue, especially with lower pressure operations, since the differential pressure required to overcome a given biasing spring and open the valve will be reduced accordingly at the same time. For such reasons, the check valves of this invention will pref erably have a valve seat no less than about one half inch in diameter and a valve chamber with a diameter with at least about one half inch larger than the valve seat. It is also preferred thatthey be designed for a maximum axial displacmentofthevalve member in said valve chamber of not substantially more than one quarter of an inch.

Turning now to FIG. 2, a very similar unit is depicted wherein most components are virtually the same and bear the same reference numerals as in FIG. 1. Attention is directed to the following improved features or optional modifications especially illustrated in FIG. 2. First, minor changes have been effected in directly opposed complementary annular seats 16 and 18; namely, soft gasket 17 has now been inserted between seats 16 and 18, while seat 16 on head section 12 is now formed as a raised rib while seat 18 on tail section 14 is now a recessed groove. The remaining changes chiefly concern the disk-shaped valve member. Thus, valve member 8' is modified by the addition of a concentric raised, cylindrical projection 7 on its upstream side sized to fit th rough port 10 and extend up into fluid supply passageway 11.Also, the ring seal on the upstream side of valve member 8' is provided in the form of an elastomeric O-ring 9' wedged into a recessed annular groove 6 and the downstream side of valve member 8' has a shallow concentric recess 27 therein sized to receive the upstream end of biasing spring 28. The latter feature plus the addition of projection 7 provides more stable support and more uniform alignment to valve member 8', so that the positioning of the completed valve assembly relative to the vertical during its actual operation becomes relatively unimportant.

FIG. 3 demonstrates a specialized and highly advantageous embodiment of the check valve of this invention involving its intimate combination and integration with a fluid jet ejector type vacuum unit in order to prevent back flow of the ejector working fluid into the fluid supply system being educted during operating interruptions. In FIG. 3 head section 12 is essentially unchanged except with regard to the nature of the valve seat formed on its downstream end face; namely, instead of the flat, uniform annular valve seat 13 used in FIG. 1 and FIG. 2, the present valve seat is formed by an elastomeric O-ring 13' wedged into a recessed annular groove 15 having a dove-tailed cross-sectional shape. Also, the concentric raised projection 7' on the upstream side of valve member 8" is in the shape of a truncated cone rather than of cylindrical form like projection 7 of FIG. 2.

However, the most drastic modification depicted in FIG.3 involves tail section 14 and particularlythe fluid discharge passageway portion of same. Thus this portion of tail section 14 is considerably larger than in FIGS. 1 and 2 and both threaded fluid outlet opening 24 and the portion of fluid discharge passageway 25 directly in line with same have been replaced by a wide open bore 30 extending com pletely through tail section 14 with larger diameter, shallow concentric wells 32 and 32' at either end thereof. Said wells 32 and 32' are formed with flat annular shoulders therein having sealing gaskets 31 and 31' seated thereon.

The ejector assembly 40 (depicted in full view rather than in section) is operatively installed in said tail section 14 so that its suction chamber 42 extends coaxiallythrough bore 30 and communicates with the surrounding annular space therein through lat eral openings 43. Suction chamber 42 is provided at its downstream end with externally threaded end portion 44 having tapered threads and at its upstream end with connection ring 46 which is externally sized to fit into recessed well 32. Internally mounted through ring 46 is a constriction jet nozzle (not shown) which extends through suction chamber 42 from its upstream connection with working fluid inlet fitting 47. The downstream end of said jet nozzle thus discharges into the converging section of a venturi shaped diffuser within socket housing 48.

The head portion 49 of socket housing 48 is internally threaded to mate with externally threaded end portion 44 and is externally sized to fit into recessed well 32'. Threaded portion 44 of suction chamber 42 is so dimensioned that ring 46 and the head portion 49 of socket housing 48 will become seated on gaskets 31 and 31' respectively during the threading engagement of portion 44 into head portion 49.

FIG. 4 illustrates the same type of combination unit as FIG. 3 wherein the tail section 14 is enlarged and modified to incorporate an ejector type suction device. However, in FIG. 4, the bore 30 provided to accommodate said suction device is simply shown open and empty without any ejector parts installed therein. Other noteworthy modifications depicted in FIG. 4 include the following. An O-ring 17' confined in annular groove 23 in head section 12 is employed to aid in forming a fluid tight annular seal between head section 12 and tail section 14, rather than the gasket 17 shown in FIGS. 2 and 3. Also, the O-ring 9' used to form the ring seal on the valve member 5 is wedged into a recessed groove 6' having a dovetailed cross-sectional shape.Again, the concentric raised projection 7" on the upstream side of diskshaped valve member 5 is in the form of a truncated cone having an included cone angle of about 60" much line projection 7' in FIG. 3. However, in FIG. 4 the downstream part of fluid supply passageway 11 communicating with central valve port has a diverging conical shape with an included cone angle substantially matching that of projection 7".

In general, included cone angles of up to about 90" are quite satisfactory on the above described parts in obtaining increased stability in guiding the axial movement of the disk-shaped valve member, although angles between about 45" and about 75" are most beneficial. It is also usually preferred that the included cone angle of the surrounding fluid passageway not substantially exceed that of the raised projection on the upstream side of the diskshaped valve member. Thus, maintaining such relationships not only insures freedom of axial motion between open positions of the valve member but also results in more generous annular fluid flow capacity for a given sized unit at a given axial displacement of the valve member.

Except four biasing spring 28, which should be made of a suitable metal or metal alloy wire, it will be seen that all of the components of the subject valves which actually contact the fluid being processed are basically simple in shape and form. Therefore, these various components can be fabricated as needed from a wide variety of materials in order to withstand working conditions such as temperature, pressure and activity of the fluid medium. For example, most of the basic parts can be mass produced by such economical techniques as metal casting, plastic molding, etc. and only certain minor modification thereof will have to be effected by machining, boring, threading or other specialized techniques.

One of the primary uses for the combination units shown in FIGS. 3 and 4 is for contacting aggressive gases such as chlorine, sulfur dioxide, ammonia, carbon dioxide and the like with aqueous or other liquid streams. In fabricating such units, it has been found advisable to make all structural parts out of corrosion resistant plastic materials, such as PVC and ABS compounds, fluoroplastics or epoxy resins, and to make O-rings and gaskets out of elastomeric materials such as neoprene, fluorinated hydrocarbon polymers and the like.

While my invention has been described in considerable detail in connection with certain specific forms and preferred embodiments, it is to be understood that such descriptive detail is not intended to limit the scope of my invention beyond that set forth in the appended claims.

Claims (16)

1. A relatively compact check valve assembly with good flow capacity comprising a two piece body composed of a fluid supply head section and a fluid discharge tail section having complementary annular seats on opposing end faces thereof shaped to fit together closely and cooperative joining means for drawing said sections together to form a fluid tight annular joint between said seats surrounding an enclosed valve chamber of cylindrical shape, said head section having a fluid supply passageway through same communicating with the upstream end of said valve chamber through a central port with a surrounding end face having a uniform annular valve seat thereon; a rigid, disk-shaped valve member the outer diameter of which provides ample annular clearance forfluid flow while assuring a loose coaxial alignment of same in said chamber, said member having a cooperating ring seal on its upstream side directly opposed to said valve seat; and a substantially coaxial biasing spring mounted on said tail section and bearing against the downstream side of said valve member, said tail section having a fluid discharge passageway running through same from said valve chamber.

2. A check valve assembly as described in claim 1 wherein said valve member has a concentric cylindrical recess in its downstream side into which the upstream end of said biasing spring extends in a stable supportive fit.

3. A check valve assembly as described in claim 1 wherein either said annular valve seat or said cooperating ring seal includes an elastomeric O-ring held in a supportive annular groove.

4. A check valve assembly as described in claim 3 wherein said groove has a dove tail cross-section.

5. A check valve assembly as described in claim 1 wherein the dameter of said valve seat is at least about one half inch and said chamber has a diameter at least about one half inch larger than said seat.

6. A check valve assembly as described in claim 1 wherein said valve chamber is dimensioned so that the maximum axial displacement of said valve member is not substantially more than one quarter of an inch.

7. A check valve assembly as described in claim 1 wherein the upstream side of said valve member has a concentric raised section sized to fit through said concentric port and extend up into the adjacent portion of said fluid supply passageway.

8. A check valve assembly as described in claim 7 wherein the height of said raised section is greater than the maximum possible axial deflection of said valve member in said chamber.

9. A check valve assembly as described in claim 7 wherein the final portion of said fluid supply passageway has a symmetrical diverging conical shape with said concentric port serving as its base and said raised section on the valve member has a symmetrical frustoconical shape with about the same included cone angle.

10. A check valve assembly as described in claim 9 wherein both of said shapes have included cone angles of not substantially more than about 90".

11. A check valve assembly as described in claim 1 wherein an elastomeric gasket is included between said complementary annular seats on the opposing end faces of said body sections.

12. A check valve assembly as described in claim 11 wherein said gasket is in the form of an O-ring held in a concentric annular groove on the end face of said head section surrounding said valve seat.

13. A check valve assembly as described in claim 1 wherein said cooperative joining means comprises a series of bolts connecting said head and tail sec tions together through matching symmetrically spaced bolt holes located in solid body portions of said sections on the outside of said mating annular seats.

14. A check valve assembly as described in claim 1 wherein substantially all internal portions of the same except said biasing spring are composed of non-metallic material.

15. A check valve assembly as described in claim 1 wherein said fluid discharge passageway in said tail section is dimensioned to accommodate therewithin a fluid jet ejector type suction device.

16. A check valve assembly constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.