FLUID FLOW REGULATING VALVE AND SYSTEM

Abstract: Fluid distribution systems such as underground sprinkling systems using orifices as flow regulators limit the system to a relatively small range of fluid pressure variation and tend to become blocked by foreign particles. Here a fluid flow regulating valve is inserted in line with a fluid conducting medium to regulate the flow therethrough over a widely varying range of pressure differentials across the valve. The valve is constructed of a body portion (48) having a fluid passageway therethrough terminating at one end in a land (56) having an empirically derived, compound curved section. A compliant reed (58) is affixed to the body portion adjacent the land and operates to press against and conform with the land in response to increasing fluid pressure differential across the reed whereby the rate of fluid flow through the valve remains substantially constant. In an alternative embodiment of the invention, a second similarly shaped land is provided adjacent the reed and opposite the other land to provide bidirectional flow control. The lands are integral portions of the body portion of the valve which is constructed of molded plastic or the like. The reed comprises thin metal shimstock or the like which has been heat staked to the body portion.

Description: FLUID FLOW REGULATING VALVE AND SYSTEM INTRODUCTION This invention relates to apparatus for regulating the flow of fluid in a system and the systems within which such apparatus are implemented and specifically to such apparatus and systems which provide constant flow rates therethrough over widely varying fluid pressure differentials. BACKGROUND OF THE INVENTION Fluid distribution systems such as underground sprinklers, irrigation systems, building fire control networks, and the like have long used fluid flow rate devices to insure equalized pressure and flow through their several branches. The equaliza¬ tion of flow is particularly important in hydronic systems having headers of restricted size such as power plant condensers and solar collectors. These systems typically employ fluids at relatively high temperatures passing through pipes, conduits and the like where uniform distributi on of the fluid and dissipation the heat associated therewith is important for the efficient operation of the system. Additionally, fluid distribution systems having many branches require some form of constant pressure regulation to insure that the system's fluid will reach all the branches at sufficient pressure. Constant fluid flow regulation is typically achieved through headers of hydronic systems. These valves typically comprise a housing with an aperture passing therethrough axially with the flow of fluid in the system. A reed is affixed to the body and covers one end of the aperture to partially block t fluid flow therethrough. The reed is typically arcuate in shape and has a carefully tailored spring constant causing i to resist the pressure applied by a pressure drop across the reed in a manner which will approximate constant fluid flow over varying pressure drops. The area in which the reed mee the opening of the aperture is typically flat and thus the flow rate characteristic of the valve is controlled solely b the spring constant of the reed. Because the spring constan must be carefully tailored, the reeds typically are of a relatively large size and must be secured to the housing by means of screws and other suitable hardware. Because of this characteristic such valves are often expensive and therefore uncσmpetitive in many system applications. They are also physically large and are thus suitable only for systems havi relatively large flow rates. BRIEF DESCRIPTION OF THE INVENTION The present invention provides a fluid regulating valve which is extremely inexpensive, self-cleaning, lends itself minaturization and is applicable to systems having relativel low flow rates. Additionally, the present invention provides a device which employs a reed which does not require a caref tailored spring constant and is easily manufactured. These advantages are achieved according to the present invention b the provision of a fluid flow regulating valve comprising a body portion having a fluid passageway therethrough terminati in a land having a curved section, the exact configuration o which is empirically derived. Compliant reed means are disp adjacent the land and operate to substantially conform with curved section in response to increasing fluid pressure acros the reed whereby the rate of fluid flow through the valve remains substantially constant. In the preferred embodiment of the invention the flow regulating valve comprises a body portion constructed of a single piece of molded material having the land integrally molded therein located substantially on a plane oblique to the direction of fluid flow. The reed is constructed of metallic foil or extremely thin shimstock which has been affixed to the body of the valve adjacent the land to operate as a cantilever. The fluid flow through the " valve causes a pressure drop across the reed causing it to be displaced toward the land and gradually conform to the section of the land with increasing fluid pressure. As the reed conforms more and more closely to the shape of the land, the opening through which the fluid must pass is reduced in size thus controlling the flow rate through the valve. The shape of the land in the preferred embodiment of the invention is a compound curve comprising a substantially concave (with respect to the oblique plane) high pressure region and a substantially convex low pressure region contig¬ uously separated by a reed supporting region. The low pressure region tends to be closed by the reed first with increasing pressure drop across the reed thereby diverting the fluid to pass through the high pressure region of the land. As the pressure drop across the reed increases further, the high pressure region of the land is gradually closed by that portion of the reed associated therewith. In an alternative embodiment of the invention, both the high pressure region and the low pressure region of the land are substantially concave with respect to the oblique plane. In another alternative embodiment of the invention, reed stop means are provided to prevent substantially deflection of the reed if the valve is inadvertently placed in a reverse flow condition, thereby preventing any deformation or damage to the valve . In still another alternative embodiment of the invention, a second land is defined by the passage through the body porti the land being adjacent the reed but opposite the first land. In this embodiment, both ends of the reed are operatively enga with a biasing means such as an axially disposed spring which biases the reed towards a planar configuration. As fluid flow through the valve in either direction, the reed tends to be deflected in that direction and, in cooperation with the land downstream of the reed, controls the flow rate through the val Various other features and advantages of this invention w become apparent upon reading the following specification, whic along with the patent drawings, describes and discloses a preferred and illustrative embodiment of the invention in detail. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 illustrates a longitudinal cross sectional view a typical prior art reed flow control valve; FIGURE 2 illustrates a solar collector system employing a fluid flow regulating valve embodying the present invention; FIGURE 3 is a flow rate versus pressure drop graph illustrating the operating characteristic of the. invention flo regulating valve as well as that of a relatively small and a relatively large orifice; FIGURE 4 shows an end view of a fluid flow regulating val embodying the present invention; FIGURE 5 is a longitudinal cross sectional view of the fl flow regulating valve of FIGURE 4; FIGURE 6 is a portion of the sectional view of the fluid . flow regulating valve of FIGURE 5 shown on an enlarged scale; FIGURE 7 is a longitudinal cross sectional view of an alternative embodiment of present invention; FIGURE 8 is a longitudinal cross sectional view of anothe alternative embodiment of the present invention; and FIGURE 9 is a transverse cross sectional view taken on li 9-9 of FIGURE 8. O DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGURE 1, a typical prior art reed flow control valve 10 is illustrated, comprising a substantially cylindrical housing 12 having outer surface threads 14 at each end thereof for interconnection with a pipe or other fluid conducting eans. Housing 12 is substantially closed by a central wall member or partition 16. Communication between the two ends of valve 10 through partition 16 is provided by an axially disposed bore 18. The upstream end or land 20 of bore 18 is partially covered by a flexible reed 22. Reed 22 is mounted as a cantilever to wall member 16 by means of a screw 24 and supporting washer 26. The free end of reed 22 is curved to the left away from wall member 16 and is constructed of metal or other material which will provide a determinable and highly reproducible spring const-ant. As fluid flows through valve 10 (from left to right) passing through bore 18, a pressure drop across reed 22 is created thereby urging the free end of reed 22 toward land 20. All fluid passing through valve 10 must pass through bore 18 and thus, as the pressure drop across reed 22 increases, the effective area of bore 18 through" which the fluid must pass • decreases. The spring constant of reed 22 must be derived empirically to achieve a given desired flow characteristic. Referring to FIGURE 2, a fluid distribution system 28 is illustrated comprising five solar collector panels 30 collec- tively interconnected in series with a pump 32 and a heat storage tank 34 through fluid conducting conduit 36. Manually controlled valves 38 are provided for evacuating the system. Each solar collector 30 comprises two manifolds or headers 40 interconnected through a parallel combination of five conducting branches 42. Within each branch 42, substantially midway between the two headers 40 is disposed a fluid flow regulating valve 44. The headers 40 of each of the solar collectors 30 are connected in series whereby each of the conducting branches 40 are affectively connected in parallel. Relatively cool fluid is pumped from the lower portion of storage tank 34 through lefthandmost valve 38 by pump 32 into lower headers 40 of solar collectors 30. The fluid flows upwardly through each of the conducting branches 42 and their associated fluid flow regulating valves 44 into the upper headers 40 for return to 5. the upper portion of storage tank 34 via conduit 36 and right- handmost valve 38. Each regulating valve 44 is calibrated to the same flow rate (5 gallons per hour in the present example) . Thereby, the flow rate through each of the conducting branches 42 is uniform over varying pressure differentials as well as 0 constant between each of the conducting branches 42. Solar energy is absorbed by the fluid as it passes through the branche 42 and thus, the temperature of the fluid in the storage tank 34 is increased. This thermal energy is removed by a secondary system (not illustrated) of the type well known in the art. 5 Any number of different fluids could be employed in this system depending upon the system's parameters including water, glycol, or silicone. If, due to ambient temperature conditions or other factors, it is desired to drain the system 28, valves 38 are closed and pump 32 flushes the fluid into suitable drain 0 storage means 46. Referring to FIGURE 3 the flow rate versus drop operating characteristic of regulating valve 44 is illustrated and contrasted with those of large and small fixed orifices. If, for example, a constant flow rate of five gallons per hour were 5 desired through each conducting branch 42, an orifice of appro-, priate dimension could be employed if the pressure source in the system were highly regulated and constant. However, in typical existing systems, pressure drop across the regulating valve or orifice varies substantially and thus, the use of orifices would 0 have only limited value if efficient system operation demanded relatively constant flow rates through each of the branches 42. Referring to FIGURES 4 and 5, the internal details of th fluid flow regulating valve 44 are illustrated. The valve 44 comprises a body portion 48 which is injection molded of 5 plastic or other suitable material. The body portion 48 is substantially cylindrical and has a fluid passageway 50 passing substantially axially therethrough. The peripheral surface -g j near the righthand end of valve 44 has an area of reduced diameter 52 which accommodates an O-ring 54. The outer diameter of the body portion 48 is dimensioned to closely fit within a conducting branch 42 and O-ring 54 serves to position and retain valve 44 within branch 42 with which it is associated as well as to provide a seal between the two, thereby insuring that all fluid flowing through branch 42 passes through fluid passageway 50. Although passageway 50 is illustrated as being entirely defined by body portion 48, it is contemplated that the passageway could be defined by the outer surface of body portion 48 and the inner surface of branch 42 with which it is associated. Accordingly, as used herein, 'passageway' should be broadly construed. Fluid passageway 50 terminates at the left end in a land 56 integrally formed in body portion 48 at an angle oblique to the direction of fluid flow through conducting branches 42. Land 56 has an empirically derived compound curved section. A compliant reed 58 is heat staked to body portion 48 and is cantilevered over land 56. Reed 58 is preferrably constructed of metal foil or extremely thin stainless steel shimstσck having a relatively low characteristic spring constant. It is contemplated that in some application such as solar collector, it may be desirable to increase fluid flow with increasing fluid temperature to limit maximum temperature. In other applications, such as heat radiators or convectors, it may be desirable to increase fluid flow with decreasing fluid temperature. By making the reed 58 of bimetal material valve 44 can be biased reed protector during installation and to serve as a reed stop in application should a reverse flow situation occur. Guard 66 abuts and is retained by a step 68 formed in the outer surface of body portion 48. An ultrasonic weld 70 also aids to secure guard 66 to body portion 48. Referring to FIGURE 6, an enlarged view of land 56 and reed 58 is illustrated showing the interaction between the two over varying pressure differentials. Land 56 is located substantially on a plane oblique to the direction of fluid flow and is divided into a low pressure region 70, a high pressure region 72, and an intermediate reed support region 74. Low pressure region 70 is substantially concave with respect to the oblique plane while high pressure region 72 is substantially convex. The undulating land surface defined by low pressure region 70, high pressure region 72, and inter¬ mediate reed support region 74 is contiguous, but may vary in shape substantially for various applications. Reed 58 is illustrated in solid line in the planar configuration it would assume in a substantially no flow condition. In appli- cation, fluid would be flowing from left to right and when the flow encountered reed 58, a pressure differential across reed 58 would be developed. This pressure differential would deflect reed 58 toward land 56 as illustrated in the broken line reed 58A. By way of example, the solid line reed 58 is illustrated at the no flow or zero pounds per square inch (PSI pressure differential condition. Reed 58A is illustrated at the position it would assume at approximately 3 psi pressure drop. Reed 58B illustrates the position it would assume at approximately 5 psi at which reed 58 would contact reed suppor region 74 of land 56 and the uppermost portion of the free end of reed 58 would contact body portion 48. At a 5 psi pressure drop, fluid is entering fluid passage 50 through the spaces defined by reed 58B and the pressure region 70 and high pressure region 72. Reed 58C illustrates the configuration the reed 58 would assume at approximately 12 psi. The opening associated with low pressure region 70 tends to be closing at this point while high pressure region 72 remains substantially ( __ ° open. Accordingly, the majority of the fluid passing into fluid passageway 50 enters via high pressure region 72. Reed 58D illustrates the position the reed would assume at approximately 30 psi pressure drop. At this position low pressure region 70 is substantially closed while high pressure region 72 is partially closed. At this position most of the fluid entering the.fluid passage 50 enters through high pressure region 72. Although the exact shape of the land 56 was empirically derived to result in a characteristic as illustrated in FIGURE 3, the main advantage in the present invention as opposed to the prior art is in the reproducibility of the contour as a part of body portion 48 as opposed to tailored reeds 22 found inthe prior art. The preferred material in reed 58 is 0.001 inch stainless steel shimstock, but it is contemplated that other equivalent or suitable materials could be employed. The preferred embodiment of the invention results in a highly reproducible and extremely inexpensive valve which can be minaturized to a point well beyond the capability of. prior art devices. As a way of example, the preferred embodiment of the invention, when applied to a solar panel which passes 5 gallons per hour through each of its branches requires a valve 44 having an outside diameter of only 0.3 inches . Referring to FIGURE 7 an alternative embodiment of the invention is illustrated. A valve 76 comprises an injection molded body 78 having a fluid passageway 80 therethrough. An O-ring 54 is provided as described in the discussion of the preferred embodiment of the invention. The reed guard 66 of the preferred embodiment is eliminated and a V-shaped reed receiving slot 82 is integrally formed in body 78. In a no flow condition reed 58, which is staked to the body 78 in a manner similar to that described in the discussion of the preferred embodiment of the invention, rests against the lower¬ most surface of slot 82. Additionally, reed 58 rests against OMPI a reed support region 84. Concave high and low pressure regions 88 and 86 respectively are provided which, function substantially as described in the discussion of the pre¬ ferred embodiment. Because contact between reed 58 and receiving slot 82 is maintained at all flow conditions (except reverse flow) , reed 58 operates as a flexible beam as opposed to a cantilever as in the preferred embodiment of the invention. Referring to FIGURES 8 and 9, a second alternative embodiment of the present invention is illustrated. A two-way fluid flow regulating valve 90 is comprised of a body portion 92 of injection molded plastic or the like having a substantially axially disposed fluid passageway 94 passing therethrough. Areas of reduced outer diameter 96 are provided near each end of body 92 to accommodate O-rings 98. A central area of reduced diameter 100 is provided to accom¬ modate a spring 102 which is disposed substantially coaxially with body 92. The fluid passageway 94 opens into an axially elongated central chamber 104 which defines two laterally opposed lands 106. A compliant reed 108 is disposed substan¬ tially axially within central chamber 104 and is supported at each end by a spring engaging member 110 which extends radiall through the' outer surface of body 92 in the area of the centra reduced diameter 100. Spring 102 is compressed and abuts the innermost surfaces of spring engaging member 110 urging them axially outwardly. Spring 102 thus operates to urge reed 108 into a substantially axially orientated planar configuration. When the central portion of reed 108 is deflected in either direction by the flow of fluid through passageway 94, spring engaging members 110 are drawn inwardly further compressing spring 102. Spring engaging members 110 are axially slidably disposable in slots 112 which open into cental chamber 104. The present alternative embodiment eliminates the chance of placing flow control valve 90 in a conducting branch backward. In application, fluid enters one end of body portion 92 throug fluid passageway 94 and enters central chamber 104 crea pressure drop across reed 108 thereby deflecting it in downstream direction. As the pressure drop increases, reed 108 closes upon one ' of the lands 106 as described in the discussion of the preferred embodiment of the invention. Reed 108 is illustrated in two intermediate positions 108A and 108B illustrating its closure upon land 106. The fluid then passes into the downstream portion of fluid passageway 94 through the gap defined by reed 108 and land 106. It is to be understood that the invention has been described with reference to specific embodiments which provide the features and advantages previously described, and that such specific embodiments are susceptible to modification, as will be apparent to those skilled in the art. Accordingly, the foregoing description is not to be construed in a limiting sense.

Claims: C L A I S WHAT IS CLAIMED IS: 1. A fluid flow regulating valve comprising: a body portion including a fluid passageway therethrough which terminates in a land having a curved section; and compliant reed means disposed adjacent said land and operative to substantially conform with said curved section in response to increasing fluid pressure across said reed whereby the rate of fluid flow through said valve remains substantially constant. 2. The flow regulating valve of Claim 1,. wherein said land is integrally molded in said body portion. 3. The flow regulating valve of Claim 1, wherein said reed is affixed to said body portion such as by heat staking and operates as a cantilever. 4. The flow regulating valve of Claim 1, wherein said body portion is constructed of molded plastic. 5. The flow regulating valve of Claim 1, wherein said reed is constructed of metal shimstock. 6. The flow regulating valve of Claim 1, wherein said land comprises substantially convex high pressure region and a substantially concave low pressure region. 7. The flow regulating valve of Claim 1, wherein said land comprises a substantially concave high pressure region and a substantially concave low pressure region. 8. The flow regulating valve of Claim 6 or 7, wherein said land further comprises a reed supporting region disposed intermediate said high and low pressure region. 9. The flow regulating valve of Claim 1, f rther comprising reed stop means operative to prevent substantial deflection of said reed when said valve is in a reverse flow condition. 10. The flow regulating valve of Claim 1, wherein said body portion includes a second land disposed adjacent said reed and opposite the first said land. 11. The flow regulating valve of Claim 10, further comprising spring means operative to bias said reed towards a substantially planar configuration. 12. A fluid flow regulating valve of the type adapted for implementation within a fluid conductor such as a pipe, said valve comprising: a body portion including a fluid passageway therethrough which terminates in a land having a curved section integrally formed in said body portion located substantially on a plane oblique to the direction of fluid flow; and compliant reed means disposed adjacent said land and operative to substantially conform with said curved section in response to increasing fluid pressure across said reed whereby the rate of fluid flow through said valve remains substantially constant. 13. The flow regulating valve of Claim 12, f rther comprising seal means adapted to be disposed intermediate said fluid conductor and said body portion. 14. The flow regulating valve of Claim 13, wherein said reed is affixed to said body portion and operates as a cantilever. 15. The flow regulating valve of Claim 14, wherein said land comprises a substantially convex high pressure region and a substantially concave low pressure region. 16. The flow regulating valve of Claim 14, wherein said land comprises a substantially concave high pressure region and a substantially concave low pressure region. "~ 17. The flow regulating valve of Claims 15 or 16, wherein said land further comprises a reed supporting region disposed intermediate said high and low pressure regions. 18. The flow regulating valve of Claim 12, further comprising reed stop means operative to prevent substantial deflection of said reed when said valve is in a reverse flow condition. 19. The flow regulating valve of Claim 12, wherein said body portion includes a second land disposed adjacent said reed and opposite the first said land. 20. The flow regulating valve of Claim 19, further comprising spring means operative to bias said reed towards a substantially planar configuration. 21. The flow regulating valve of Claim 12, wherein said body portion is constructed*σf molded plastic. 22. The flow regulating valve of Claim 12, wherein said reed is constructed of metal shimstock. 23. The flow regulating valve of Claim 12, wherein said reed is affixed to said body portion such as by heat staking and operates as a flexible beam. 24. A fluid distribution system comprising: a plurality of mutually interconnected fluid conducting branches; and at least one fluid flow regulating valve disposed within each said branch, each said valve comprising a body portion including a fluid passageway -therethrough which terminates in a land having a curved section and compliant reed means disposed adjacent said land and operative to substantially conform with said curved section in response to increasing fluid pressure across said reed whereby the rate of fluid flow through each said branch remains substantially constant. 25. The fluid distribution system of Claim 22, wherein the rate of fluid flow through each of said branches is substantially equal to that through each of the other branche 26. The fluid distribution system of Claim 24, wherein said distribution system comprises a hydronic system includin at least two manifolds interconnected by a parallel combinati of at least two said branches. 27. The fluid distribution system of Claim 26, wherein said distribution system further comprises heat storage means and, fluid pumping means in fluid communication with said manifolds.

Inventors: WALSH M, WORTHEN R
Applicants: EATON CORP
Application year: 1979
Main classification: F16K17
IPC codes: A01G25, F16K15, F16K17, G05D7