US3794068A

US3794068A - Negator-spring, rolling-tape, flow-control, quiet throttling valve

Info

Publication number: US3794068A
Application number: US00354061A
Authority: US
Inventors: R Milroy
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-04-24
Filing date: 1973-04-24
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

A negator-spring is used as the rolling flow-control gate of a flow-control valve. The negator-spring is a strip of flat spring stock which is stressed on one side to make it roll upon itself. Fluid flows across the roll of negator-spring so that a pressure differential exists across the negator-spring roll. Any increase in the flow rate would cause the negator-spring to be extended or rolled out further upon the porous surface. The negator-spring is fixed at one end and is forced by the differential pressure to roll out over a port containing material which provides a fluid passage through its pores. Traditional springs increase or decrease in force with the amount extension. The spring force of the negator-spring is constant all along its length. Therefore, the valve configuration maintains the flow rate at a constant level since any increase or decrease in the differential pressure across the spring roll will cause a corresponding extension or contraction of the negator-spring which in turn will result in a change in the flow cross-sectional area of the porous material port until an equilibrium is again reached. The flow through the porous material causes quiet throttling of the fluid while the flow rate remains constant by the action of the negator-spring.

Description

United States tent Milroy Feb. 26, W74

[ NEGATOR-SPRING, ROLLING-TAPE, gate of a flow-control valve. The negator-spring is a FLOW-CONTROL, QUIET THROTTLING strip of flat spring stock which is stressed on one side VALVE to make it roll upon itself. Fluid flows across the roll of negator'spring so that a pressure differential exists [76] Inventor: Rlcham Mummy 2 Cherry across the negator-spring roll. Any increase in the flow Grove Annapolis 21401 rate would cause the negator-spring to be extended or [22] Filed: Apr. 24, 1973 rolled out further upon the porous surface. The negator-s ring is fixed at one end and is forced b the dif- [21] Appl' feren iial pressure to roll out over a port cgntaining material which provides a fluid passage through its [52] [1.8. Ci 137/497, 251/337, 251 /DIG. 2 p r Traditional p g i r e or cr in [5 1] Int. Cl. 605d 7/00 o ce ith the amount extension. The spring force of [58] Fi ld f S h 251/DIG 2, 337; 137/497, 62528 the negator-spring is constant all along its length. Therefore, the valve configuration maintains the flow [56] References Cited rate at a constant level since any increase or decrease UNITED STATES PATENTS in the differential pressure across the spring rollfwill cause a corresponding extension or contraction o the 34:23,??? 2:32 Hayes 137/517 negatopspring which in turn will result in a change in 9/197] the flow cross-sectional area of the porous material 3,726,313 4/1973 Pandya 251/010. 2 P until an equilibrium is again reached- The flow Primary Examiner-Henry T. Klinksiek Assistant Examiner-Robert I. Miller Attorney, Agent, or Firm-R. S. Sciascia; Q. E. Hodges [57] ABSTRACT A negator-spring is used as the rolling flow-control through the porous material causes quiet throttling of the fluid while the flow rate remains constant by the action of the negator-spring.

9 Claims, 8 Drawing Figures i TX 29 a F 43o, S 4

V//// 33 g Z K 444/ 4 //A 34 PRESSURE 46 FORCE 34 SPRING FORCE 3s k i l X 5 W /7 a s as y A PATENTED 3.794.068

SHEET 1 [IF 3 FIG. 2

F/GIZG.

NEGATOR-SPRING, ROLLING-TAPE, FLOW-CONTROL, QUIET THROTTLING VALVE The invention described herein may be manufactured and used by or for the Government of the United 5 States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION This invention relates to a quiet throttling valve which uses a negator-spring as the rolling tape valve gate. The negator-spring automatically regulates the flow through the valve to keep it constant. According to the prior art, rolling tape gates have been used to close off flow through a high strength porous material. The tape is rolled out on the surface of the porous material and thereby determines the area of the porous material through which flow will be allowed. In the prior art, the rolling tape is mechanically held at a preselected position. The surface area of the porous material through which flow is allowed remains constant irrespective of any change in the external demands on the valve and can be changed only upon physically rolling or extending the tape and fixing it in another desired position. This type of valve does not provide for automatic flow control. Where the prior art does provide for the constant volume control of fluid flow such as in the patent to Hayes, US. Pat. No. 3,049,146, the apparatus used is relatively complex, cumbersome, and expensive to produce. Hayes uses a elongated rectangular flexible curtain equal to the width of a flow duct. The curtain has one end wound around a shaft and the other end attached to the side of the duct adjacent a screen. The curtain is able to roll and unroll about the shaft outside the duct area of flow and in response to changes in the flow pressure of the curtain.

SUMMARY OF THE INVENTION The purpose of this invention is to quietly control the fluid flow at a constant rate under varied pressure conditions. This is accomplished by directing flow through a housing which contains a high strength porous material between an upstream and downstream portion of the housing. The outer end of a negator-spring is fixed with respect to the porous material to allow the negator-spring to freely roll and unroll to form a fluid-tight closure over progressive areas of the high strength porous material. An adjustable side plate can be provided to allow the fluid to flow around the side of the roll of 50 the negator-spring as well as over it. The desired quantity of flow can be preset by adjusting the side plate. Once the preset flow is reached and the side plate is in its fixed position, any change in the flow rate will cause a change in the extended length of the negator-spring.

The quantity of flow through a frictional valve, for example, such as one in which the flow is through a porous material, can be expressed as follows:

Q quantity of flow;

AP the differential pressure across the valve;

A the surface area of the porous material through which flow is allowed;

t the thickness of the porous material; and,

p. the viscosity of the fluid.

Unlike other springs which require a linear increase in force as they are increasingly deflected, the spring force of the standard negator-spring is constant all along its length. Therefore, when the negator-spring is used as a rolling gate in a quiet throttling valve such as in the instant invention, any change in flow quantity will cause a corresponding increase or decrease in the differential pressure across the spring roll. Therefore, a change in quantity of flow will cause the spring to move and cause a change in flow area until the original differential pressure across the roll is reached. If a particular quantity of flow is allowed through the valve by adjusting the side plate of the valve, the spring will reach an equilibrium state. If the upstream pressure remains constant, and the downstream drops, the increased differential pressure across the valve would cause a greater quantity of flow. This will cause an increase in pressure differential across the spring roll. When the negator-spring is used as a rolling gate, it will automatically respond to the increased pressure differential caused by flow and unroll across the surface of the porous material and decrease the flow crosssectional area until the preselected quantity is again reached. Similarly, if the differential pressure across the valve decreases, the negator-spring will roll up to expose a greater amount of surface area of the porous material until the previously selected quantity of flow is reached.

A standard negator-spring when extended, tends to curl up, transversely as well as from end to end. The problem created 'by this tendency when a negatorspring is, as here, used as a rolling gate in a flow control valve can be overcome in at least five ways. First, in the manufacture of the spring curved rather than flat spring stock can be used so that the negator-spring will have a tendency to roll out flat on a flat planar surface. Second, a standard negator-spring, may be used in conjunction with porous material which is concave to fit the spring when it is extended. Third, the section of porous material may be cylindrical in shape so that the negator-spring will not be required to roll out on a flat surface but will roll out along the periphery of the cylindrical surface. The standard negator-spring will roll out flat against such a curved surface. It may be fixed to either roll out on the inside or the outside of a cylindrical sleeve of porous material. Fourth, the negatorspring may be coiled up integrally with any flexible tape that will lay flat on a flat surface when rolled out. Fifth, the negator-spring may be used to apply a constant bias force to one of the-rollers of a rolamite. This combination provides an extremely free-rolling and practical rolling-gate flow-control valve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a negator-spring in a partially extended state. In its natural unextended or unforced state, the negator-spring is completely rolled upon itself.

FIG. 2 is a side view of a rolling-gate negator-spring valve where the negator-spring is rolled out longitudinally across the planar surface of a rigid porous material.

FIG. 2a is a cross-section of FIG. 2 at line AA.

FIG. 3 is a side view of a constant flow negator-spring rolling gate valve where the negator-spring rolls out around the outer circumference of a cylindrical shaped sleeve of rigid porous material.

FIG. 3a is a cross-section of FIG. 3 at line BB.

FIG. 4 is a side view of a negator-spring rolling gate flow control valve similar to FIG. 3 including an adjustable valve to adjust the flow differential pressure to balance the spring force at the desired flow.

FIG. 5 is a negator-spring rolling gate flow control valve in cross-section where the negator-spring rolls out along the internal circumference of a cylindrical sleeve of rigid porous material when the flow of fluid is introduced into the valve from an inlet in the center of the porous sleeve.

FIG. 6 is a side view of a negator-spring biased rolamite automatic flow control valve.

DESCRIPTION OF THE ALTERNATIVE EMBODIMENTS:

The instant invention provides for a constant flow regulation in a quiet throttling valve by the use of a negator-spring as a rolling gate. The negator-spring keeps the flow at a constant amount since any change in the differential pressure across the valve will cause a extension or contraction of the negator-spring thereby changing the area of porous material through which the fluid is allowed to flow with the result that the flow rate is proportionately changed. The unique application of a negator-spring as a rolling gate in a flow control valve provides the constant rate of flow monitoring capability because the negator-spring will react to any given change in flow rate in the same degree irrespective of the state of elongation of the spring. There are three indispensable components of the rolling gate negator-spn'ng flow control valve as described by this invention. These components are (i) a negator-spring, (ii) a rigid porous passage, and (iii) a valve housing.

i. Negator-spring Conventional spring devices have the common characteristic of a positive gradient, i.e., the greater the deflection of the spring, the greater is the total of the force exerted by the spring. A negator-spring is a spring device which has a zero gradient. Such a spring device is disclosed by Cook in US. Pat. No. 2,647,743, issued for August 1953 and may be made by processes disclosed by Leorment in US. Pat. Nos. 2,801,669 and 3,007,239 issued 6 Aug. 1957 and 7 Nov. 1961 respectively. When a negator-spring, such as that disclosed by Cook, extends it has a tendency to curl from side to side as well as along its length. In the context of this invention, it is necessary for the negator-spring to snuggly engage the surface of the porous material. To do this, a standard negator-spring may be used in conjunction with the external or internal surface of a cylindrical sleeve of porous material. Alternately, the surface of the porous material can be ground into a concave shape to allow complete and snug engagement between the surfaces of the negator-spring and the surface of the porous material.

It is possible to adapt a negator-spring valve to have a variety of characteristics in response to particular changes in flow. Standard negator-springs can be adapted to have a plethora of characteristic curves by adding or removing negator-spring material at selected places along the length of the negator-spring. Such changes to a negator-spring used in the context of this invention may be necessary to compensate for distortion of the negator-springs function introduced by valve configuration.

The forcing function of the negator-spring is dependent on the width, thickness and other characteristics of the negator-spring. Consequently, the negator-spring can be made to produce a variable force along its length by varying the width, but a standard device of any size or shape which has the characteristic of a negator-spring with constant width exerts the same total force at any elongation. Such a device is hereinafter referred to as negator-spring.

ii. Porous passage A porous passage is contained within the valve housing through which at least part of the valve fluid is required to pass is made up of a porous rigid material. The rigid material gives the negator-spring a rigid supporting surface as it extends and contracts to regulate the quantity of flow at a constant amount. The rigid material can be of any thickness and the surface can be made to conform to the shape of any unrolled negatorspring; for example, if a negator-spn'ng is manufactured to roll out flat then the surface made of the rigid material may be planar; where a negator-spring is found to roll out and curl upon itself transversely, the surface of the porous passage can be made concave to tit the extended portion of the negator-spring snugly; where a standard negator-spring is used, a porous passage may take the shape of a cylindrical sleeve. The passage must be porous throughout to allow quiet throttled flow through the porous material. Examples of material which may be used for the rigid porous passage are Rigimesh which is a laminated woven wire cloth produced by the Pall Corporation. Poroloy and Poroplate which are products of the filter division of the Bendix Aircraft Corporation, a volume of spherical beads which are welded to each other to form a solid porous piece of material which is then ground to form plan surfaces, laminated grooved plates, or other high strength porous media.

The porous passage can be of any shape, size or configuration which will provide a rigid surface for intimate engagement by any negator-spring device as well as quiet throttling flow for any valved fluid. Such a passage is hereinafter referred to as porous passage. iii. Valve housing The valve housing must be of rigid non-porous material which provides flow channels to direct the flow of the valved fluid from an input duct in the direction of the portion of the porous passage which is to be covered by the unrolled negator-spring. The flow must be channelled at least partially across the rolled-up portion of the negator-spring and through a portion of the porous material left uncovered by the negator-spring. To permit selectivity of a variety of flow rates for the same valve, the housing may include a means to vary the cross sectional flow area around the spring roll. This means may take the form of a movable side wall perpendicular to the edge of a standard negator-spring. This will allow a change in the quantity of the flow until the desired level of flow is reached. Then if the side plate remains in the same position, the negator-spring action will maintain the flow at the fixed quantity by the above described automatic action of the negatorspring.

The valve housing can be of any size, shape or configuration which will channel the flow of the valved fluid I as described above and allow the unencumbered action of the negator-spring rolling gate. Such a housing is hereinafter referred to as valve housing.

DESCRIPTION OF THE INVENTION A standard negator-spring 3 is shown in FIG. 1. The spring is partially extended and has a roll portion 1 and an extended portion 2. The force required to maintain the standard negator-sprin g in any position of extension is the same throughout the length of the spring. FIG. 2 shows one alternative configuration of a constant-flowrate negator-spring quiet-throttling valvercomprising a valve housing 4, a negator-spring 5, a porous passage 6 and a screw 7 which attaches one end of the negatorspring to a portion of a valve housing. The valve housing provides an input passage 8 and a fluid exit passage 9. Fluid flows into the valve through passage 8, past the fixed end of the negator-spring, over and around the negator-spring, through the porous passage 6, then into the output passage 9. FIG. 2a is a section view of FIG. 2 taken at line AA which shows the valve housing 4 for negator-spring 5, porous passage 6, inlet passage 8 and output passage 9 as well as an adjustable side plate 10. The adjustable side plate 10 can be moved parallel to the edge of the negator-spring to allow flow around the negator-spring to any desired quantity of flow. The side plate 10 can be set at an angle to compensate for the reduction in the negator-spring roll diameter as the negator-spring is extended. The angle of plate 10 also effects the dynamic response, sensitivity, stability, and the accuracy of flow control with large load pressure changes. The side plate 10 is held in place and moved by action of thumb bolt 11. Once the side plate is placed in a particular position, allowing a selected quantity of flow, the quantity will remain constant despite a variance in the differential pressure across the valve. If, for example, the input pressure remains constant and the output pressure decreases creating an increase in differential pressure across the valve and the negator-spring, the roll of the negator-spring will move along its length until it reaches a position of equilibrium which is the equivalent of the prior force of the negator-spring. If the differential pressure were to decrease to its previous state, the spring would roll up until it would reach its prior position.

FIG. 3 is a side view of an alternative rolling-tape constant-flow negator-spring quiet throttling valve. Fluid flows through input passage 20 then along the outer surface of the negator-spring l2 and around then over the spring roll 21 and caged rollers 16. Caged rollers 16 allows the free movement of spring roll 21 around the outer surface 18 of sleeve 13 which is a porous passage. The fluid continues around and over roll 21 of the negator-spring 12 and passes through the uncovered outer surface 18 of the porous sleeve 13 to a central exit passage 19 which is defined by the inner surface 17 of the porous sleeve 13. Element 22 assists in directing the flow through the valve housing. 23 is an anchor bolt for the end of -negator-spring 12. As shown in FIG. 3a, which is a cross-sectional view of FIG. 3 taken at line B-B, the valve housing 15 includes an adjustable side plate 24 whose position with respect to the side of negator-spring adjusted by turning threaded part 26.

FIG. 4 is a similar configuration to that shown in FIG. 3 but does not include a side plate for the selection of the desired quantity of flow. As an alternative to the side plate, an adjustable valve 27 would generate a differential pressure proportional to the input flow to affect the extension of the negator-spring 12.

A more sophisticated, but yet simpler alternative embodiment is shown in FIG. 5. In this FIG. a cylindrical sleeve of porous material 28 is used as the porous passage through which flow is quiet throttled. Fluid enters through a central input conduit 29 and is directed to flow along extended portion 31 of a negator-spring and over and around roll 30 of that spring and then exiting the valve through the porous material as shown. As before, bolt 32 is used to anchor one end of the negatorspring and the spring is allowed to freely roll on the inside surface of the sleeve. A standard negator-spring can be used and will roll out flat against the inside surface of the porous sleeve 28; since as previously discussed, it is rolling against a cylindrical surface. In this embodiment, a side plate similar to side plate 24 in FIG. 3a may be used to preselect a desired flow rate through the valve which will then be held constant by the action of the negator-spring.

A rolling tape constant flow valve is easily made with the negator-spring used in conjunction with a rolamite. As shown in FIG. 6, the lower wall 38 of the valve housing contains a section of porous material 39 which comprises the quiet throttling porous passages. The rolamite valve includes a rolamite tape 34 which will roll over and cover the surface 43 of the porous passage 39. The negator-spring 36 biases the rolamite tape porous passages 34 such that the porous passage surface 43 is normally uncovered. Negator-spring 36 rolls up around bearing 45 on shaft 46 extending through the segmented roller 47. Fluid ehters through passage 40 then generates a differential pressure through the flow selector valve 42 and goes through porous passages 39 to exit area 41. The valves dynamic response may be reduced by restricting passage 48.

It is apparent from the preceding description that the method and apparatus for using a negator-spring for constant flow control in a rolling gate valve may be modified considerably without departing from the invention. Therefore, the forms of the invention described herein should be considered as illustrative only and do not limit this invention beyond the limitations set forth in the following claims.

What is claimed is:

l. A constant flow quiet throttling valve comprising:

a porous passage; a valve housing containing said porous passage; and

a negator-spring within said valve housing which is fixed at its outer end and allowed to extend and roll up freely upon the surface of the porous passage in response to changes in the differential pressure across the roll of the spring to cause a change in the a valve housing containing a rolamite; area of the surface of the porous passage which is a porous passage in the surface of one rolamite plane; exposed to flow. and 2. A constant flow quiet throttling valve as described a torring fixed at it outer end and spindled to in Claim wherein Said Porous Passage is cylindrical one rolamite roller to extend and roll up freely to allow the rolamite to roll freely upon the surface of 3. A constant flow quiet throttling valve as in claim the porous passage in response to changes in the differential pressure across the negator-spring bisaid negator-spring rolls out flat against the outer surased rolamite o cause a change in the area of the face of the cylindrical porouspassage. 10 porous passage. 4. A constant flow quiet throttling valve as in claim A constant flow quiet throttling valve as in Claim 2, wherein;

said cylindrical porous passage has an input passage located in the center of the porous passage; and,

said negator-spring rolls against the inner surface of said porous passage to prevent flow through the arc segment of the porous passage covered by the extended portion of the negator-spring.

5. A constant flow quiet throttling valve as in claim 6, wherein:

said negator-spring exhibits a non-uniform force along its length. 8. A constant flow quiet throttling valve as in claim 6, wherein:

said bias force characteristics of a negator-spring are produced in the rollamite tape. 9. A constant flow quiet throttling valve as in claim 1, wherein:

said valve housing includes an adjustable valve to sewhel'elni lectively adjust the differential pressure across the Sald Valve Ilg c des a djustable valve to senegator-spring roll. lectively adjust the differential pressure across the 6. A constant flow quiet throttling valve comprising: negator-spn'ng roll.

Claims

1. A constant flow quiet throttling valve comprising: a porous passage; a valve housing containing said porous passage; and a negator-spring within said valve housing which is fixed at its outer end and allowed to extend and roll up freely upon the surface of the porous passage in response to changes in the differential pressure across the roll of the spring to cause a change in the area of the surface of the porous passage which is exposed to flow.

2. A constant flow quiet throttling valve as described in claim 1, wherein said porous passage is cylindrical.

3. A constant flow quiet throttling valve as in claim 2, wherein: said negator-spring rolls out flat against the outer surface of the cylindrical porous passage.

4. A constant flow quiet throttling valve as in claim 2, wherein; said cylindrical porous passage has an input passage located in the center of the porous passage; and, said negator-spring rolls against the inner surface of said porous passage to prevent flow through the arc segment of the porous passage covered by the extended portion of the negator-spring.

5. A constant flow quiet throttling valve as in claim 1, wherein: said valve housing includes an adjustable valve to selectively adjust the differential pressure across the negator-spring roll.

6. A constant flow quiet throttling valve comprising: a valve housing containing a rolamite; a porous passage in the surface of one rolamite plane; and a negator-spring fixed at its outer end and spindled to one rolamite roller to extend and roll up freely to allow the rolamite to roll freely upon the surface of the porous passage in response to changes in the differential pressure across the negator-spring biased rolamite to cause a change in the area of the porous passage.

7. A constant flow quiet throttling valve as in claim 6, wherein: said negator-spring exhibits a non-uniform force along its length.

8. A constant flow quiet throttling valve as in claim 6, wherein: said bias force characteristics of a negator-spring are produced in the rollamite tape.

9. A constant flow quiEt throttling valve as in claim 6, wherein: said valve housing includes an adjustable valve to selectively adjust the differential pressure across the negator-spring roll.