US 3472277 A
Description (OCR text may contain errors)
Oct. 14, 1969 RE|N|CKE ET AL 3,472,277-
MAGNETICALLY INTERLINKED MULTI-VALVE ASSEMBLY K YBY M71 v 3 E AGENT United States Patent 3,472,277 MAGNETICALLY INTERLINKED MULTI-VALVE ASSEMBLY Robert H. Reinicke, Thousand Oaks, and William B. Mayfield, Suuland, Calif., assignors to North American Rockwell Corporation, a corporation of Delaware Filed May 24, 1967, Ser. No. 641,031 Int. Cl. F16k 31/08; H01f 7/08 US. Cl. 137595 8 Claims ABSTRACT OF THE DISCLOSURE Background of the invention This invention relates to electrical valve actuators and more specifically to a magnetic circuit that interlinks and simultaneously operates multiple valves. The use of solenoid coils in conjunction with electromagnetic plungers or armatures for regulating valve motion is well established in the prior art. When individual solenoids are used to operate each of a plurality of valves it becomes difficult to precisely regulate the valves simultaneously. Though the solenoids may be hooked up in the same electrical circuit, there is always the risk of an inductive lag timing mismatch that will result in variable rather than simultaneous valve motions. The numerous and complex components of the circuit as well as its overall cost and required packaging space renders the arrangement undesirable.
Although the use of single magnetic circuits to actuate dual valves are known (e.g., British Patent No. 21,824, 1915), they are incapable of producing precise and reliable simultaneous motions of the valves. This inability arises because, unlike the instant invention, the values are not magnetically interlinked within a single electromagnetic circuit so that motion of one valve influences the motion of the other valve.
Summary of the invention Briefly stated, the instant invention contemplates a multiple valve assembly including at least two valves, each valve being connected to a valve actuating armature. The armatures are magnetically interlinked within a common magnetic circuit so that the motion of one armature influences the motion of the other armature causing the valves to move substantially simultaneously. When the magnetic circuit is energized to move the valves through their lifting strokes and the motion of one valve precedes the motion of the other valve, then the magnetic circuit operates to automatically move the previously lagging valve. This results because as the moving armature is pulled across a gap by adjacent magnetic pole faces, the narrowing gap serves to decrease the magnetic reluctance in the circuit. This in turn automatically increases the circuit flux density that soon attains a value sufficient for pulling the previously lagging armature.
Connected to each armature and valve assembly is a first return spring that constantly biases the valve toward its valve-closed position. The opposing ends of this spring are connected in a recess formed in adjacent support ice structure so that the recess may serve as a guideway for allowing the valve to move substantially axially during both its lifting and seating strokes. More specifically, the valves are poppet balls each of which is retained for free rotary movement between a ball cage connected to the armature and a second return spring. The biasing force of the second spring is constantly urged against the ball, pressing it against turned-in lips formed at the end of the ball cage that is adjacent the valve seat. By this arrangement the ball is made self centering and concludes its seating stroke by freely rolling until it locates itself in a spherical seat. In another aspect of this invention a section of the support structure forms a stop for stopping motion of the armature and preventing its mass from impacting against the ball and its seat, thus permitting a longer life of the valve. Three particular and interchangeable magnetic circuits with which this invention may be used are fully explained below.
Brief description of the drawing The advantages of the instant invention will be fully appreciated upon studying the following detailed description in conjunction with the detailed drawings in which;
FIG. 1 is a longitudinal cross-sectional view through a valve assembly formed in accordance with one embodiment of the instant invention showing a pair of ball poppet valves connected to armatures forming portions of the magnetic circuit;
FIG. 2 is a sectional view taken along the line 22 of FIG. 1 showing a pair of springs associated with one ball poppet valve for urging it toward its valve-closed position;
FIG. 3 is a schematic view illustrating the magnetic flux circuit for the valve assembly of FIG. 1;
FIG. 4 schematically illustrates a magnetic flux circuit for a second embodiment of this invention;
FIG. 5 schematically illustrates a magnetic flux circuit for a third embodiment of this invention.
Description of the preferred embodiments In accordance with one embodiment of this invention, FIG. 1 illustrates a valve assembly 10 having a housing 12. Housing 12 is sized for enclosing a C-shaped electromagnetic core 14 that is encircled by a solenoid coil 20. The distance between the inner faces of parallel arms 15 and 16 of core 14 is substantially equivalent to the length of coil 20 so that relative motion between coil 20 and core 14 is prevented. Electrical current is supplied to coil 20 through wires 24 and 26 that pass through a conventional electrical receptical 27 mounted to housing 12. Connected to the opposite sides of housing 12 is a pair of fluid inlets 31 and- 33. Integrally formed with fluid inlet sections 31 and 33 are inwardly extending wall sections 32 and 34, respectively, that are rigidly connected to the opposite ends of a flux bridge 50 whose function will be fully described. Extending outwardly from an intermediate region of flux bridge 50 is a wall 55. Rigidly connected between fluid inlet 31 and one side of wall 55 is a cup-shaped valve seat structure 41. In a similar manner rigidly connected between fluid inlet 33 and the other side of wall 55 is a cup-shaped seat structure 43. As shall be fully explained wall sections 32 and 34 cooperate with valve seat structures 41 and 43 to constitute support structure for a pair of valves.
' Valve assembly 10 may, for example, be used to achieve a highly reliable and precise mixture of two different liquids such as a fuel propellant entering inlet 31 and an oxidizer propellant entering inlet 33. -In this situation fuel propellant would enter a manifold 42 and the oxidizer propellant would enter a manifold 44, the manifolds being segregated from one another primarily by wall 55 that serves as a fluid tight partition. Premature mingling of volatile fluids capable of developing a hypergolic reaction would produce catastrophic ramifications to the valve assembly and more important to the structure in which it is incorporated. This severe risk is minimized because manifolds 42 and 44 are positively sealed from one another by stationary structural components.
Associated with each valve seat structure 41 and 43 is a valve structure 61 and 71 which are substantially identical. Valve 61 includes a ball poppet 62 that is contoured to fit in a spherical seat 45 integrally formed with valve seat structure 41. Poppet 62 regulates fuel propellant flow through an outlet 46. In a similar manner, valve seat structure 71 includes a ball poppet 72 for preventing oxidizer propellant flow through an outlet 48 when poppet 72 is positioned in its seat 47. The valves are illustrated in their closed positions in FIG. 1. Poppets 62 and 72 are retained in tubular ball cages 64 and 74 respectively. Annular cage lips 65 and 75 formed on cages 64 and 74 are turned-in (e.g. by machining or crimping). As will be fully explained the balls are retained between the cage lips 65 and 75 and springs so they are freely rotatable and self centering. Cage 64 is rigidly connected to, or integrally formed with, an armature 66 whose opposing ends 67 and 68 overlap arm and one end of flux bridge 50, respectively. In a similar manner cage 74 is connected to an armature 76 whose opposing ends 77 and 78 overlap arm 16 and the other end of flux bridge 50.
When the valves are closed, as illustrated in FIG. 1, armature 66 is spaced by a predetermined gap AX from the free end of arm 15, hereafter referred to as pole face 17. Armature 76 is likewise spaced by predetermined gap AX from pole face 18. The opposite ends of flux bridge 50 also act as pole faces for attracting the armatures. When coil is energized, as schematically depicted in FIG. 3, a predetermined magnetic flux pattern will be developed in core 14 with flux lines assuming a circuit as indicated by the arrows and dash line. lit will now be explained how the resulting flux pattern of the magnetic circuit operates to substantially simultaneously lift the ball poppets from their seats so that fluid may be discharged the same time. The geometry of the flux field is defined by core 14, armature 76, flux bridge 50' and armature 66, all of which are constructed of highly permeable magnetizable material such as soft core iron. It should be noted that inlet sections 31 and 33, wall sections 32 and 34, and Wall 55 are constructed from any non-magnetic material. As is typically the case in dual valve assemblies, the lifting action of one valve may precede the other valves due to unequal fluid or spring biasing pressures, sticking, galling, different manufacturing tolerances etc. This undesirable condititon which ordinarily results in unequal flow periods isprevented by the instant invention. This is due to the fact that armatures 66 and 76 are serially interlinked in the common magnetic circuit and, for reasons to be explained, infiuence one anothers lifting and seating motions. Assume for purposes of illustratiton that the lifting motion of armature 66 precedes the motion of armature 76 when coil 20 is energized. The magnetic attracting force exerted by pole face 17 will draw armature 66 toward pole face 17 by a finite distance thereby narrowing the gap AX and, more important, reducing the magnetic circuit reluctance. By reducing the reluctance there is a concomitant increase in the magnetic circuit flux density. This results in an increased force throughout the circuit and hence a greater pulling force will be exerted by pole face 18 upon the lagging armature 76. As the gap AX narrows between armature 66 and pole face 17 the attracting force between pole face 18 and armature 76 will be contemporaneously increased to a point where the motion of armature 76 will commence. After a short time has elapsed the previous mismatch of motion in the armatures will have been corrected and the valves will arrive at their maximum elevated position at sub- 4 stantially the same time. In this illustration precise simultaneous motion can not be attained. Since both valves are being attracted by the same flux the first to move will be the first to conclude its upward stroke.
It can thus be seen that as armature 66 begins to move toward pole face 17 narrowing its associated air gap AX the magnetic circuit automatically provides increasing force that will be exerted on lagging actuator 76, thus reducing any tendency of mismatched motions. Narrowing of one of the air gaps reduces the circuit reluctance and causes increased flux density, the resulting increased magnetic force being exerted on the lagging armature. It should be noted that there are no sliding fits or close clearances for potentially impeding valve and armature motion by friction or viscous forces. Due to this arrangement there is no opportunity for abnormal forces to resist actuation.
Associated with each poppet valve and armature assembly is a spring system for guiding and seating the valves. Since the two spring systems are identical only the system cooperating with poppet valve 62 and armature 66 will be fully described. Referring to FIG. 2, fixed to the top of armature 66 is an armature return spring 81 constructed of suitable flat spring material. The opposite ends of spring 81 are mounted in wall section 32 that serves as a support structure. Return spring 81 is disposed within a guide slot 83 constituted by a recess in wall section 32. The motion of cage 64 as poppet 62 moves through its lifting stroke is substantially axial due to the positive movement of spring 81 into guide slot 83. When the coil is deenergized, the movement cage 64 as poppet 62 moves through its seating stroke will likewise be substantially axial. The lifting and seating strokes of valve 62 through numerous cycles are repeatable and hence reliable due to the absence of valve hang-up that could be caused by binding, galling or contamination which defects are characteristic of sliding valve fits.
Extending in an arc across the width of armature 66 is another return spring or poppet load spring 91 that is bowed downwardly into biasing engagement against ball 62. Spring 91 passes through diametrically opposed openings 93 formed in the wall of cage 64. Spring 91 together with cage 64 retain ball 62 in such a manner that it may float freely and be self-centering. Assuming that at the end of its seating stroke, ball 62 fails to make a flush fit in its spherical seat 45, the downwardly biasing force supplied by spring 91 will ultimately roll ball 62 into seat 45.
It is desirable to minimize severe impact between ball 62 and its seat so as to prolong its life. To achieve this result the mass thrusting ball 62 into its seat 45 is minimized, the effective mass impacting the seat being reduced to that of the ball and load spring 91. Localized stress and fatigue are thus minimized and high endurance cycling is achieved. To accomplish this, rim 95 of cupshaped valve structure 41 serves as a stop for the downward motion of the mass constituted by armature 66 and cage 64. This excess mass is prevented by hearing against the ball 62 or its seat 45. When the magnetic circuit 1s deenergized and the attracting force of the flux density is overcome by the biasing force of return spring 81 lower peripheral portions 96 of armature 66 will ultrmately engage and be stopped by rim 95. The stopping action will follow the point in time when ball 62 initially contacts its seat. Since the ball is rotatably and loosely confined between cage lip 65 and spring 91, it is free to roll while it is being self-centered. The capacity to roll facilitates the ball entering its seat. If the ball were held rigidly in place the sliding action during seating would produce excessive friction eventually causing the seat to become eroded and thereby developing leak passageways and limiting the life of the overall valve assembly.
The influence of the magnetic circuit and the manner in which armatures 66 and 76 are magnetically interlinked also promotes substantial simultaneous valve closing.
When, referring to FIGS. 1 and 3, coil 20 is deenergized and assuming the motion of armature 66 commences before that of armature 76, the widening gap AX between pole face 17 and armature 66 will serve to increase the magnetic circuit reluctance. The direct result will be to reduce the circuit flux density, thereby reducing the holding force being exerted by pole face 18 upon armature 76. The previously motionless or lagging armature 76 will then begin to move as the biasing force in its return spring overcomes the magnetic holding force. Since this action is occurring almost instantaneously the motions of the valves through their seating strokes will be virtually simultaneous.
From the foregoing description is can now be understood how the many advantages of this invention can be achieved. In operation, assuming that valves 62 and 72 are closed so that fluid cannot be discharged from manifolds 42 and 44, respectively, coil 20 may be energized to substantially simultaneously open the valves. As armature 66, for example, under magnetic attraction exerted by pole face 17 commences its lifting stroke, with valve 72 remaining stationar, the unequal motions will rapidly be corrected. Armatures 66 and 76 are aligned serially within the same magnetic circuit so that the motion of one must influence the motion of the other As the gap between armature 66 and pole face 17 narrows, there will be a concomitant increase in the magnetic flux density that will serve to intensify magnetic attraction exerted by pole face 18 upon armature 76. When the magnetic reluctance is reduced, the pulling force on armature 76 increases to a point at which the lifting stroke of valve 72 commences. With the magnetic forces overcoming the opposing biasing spring forces, valves 62 and 72 substantially simultaneously conclude their lifting strokes so that fluid may be discharged through their respective fluid outlets at the same time. Conversely, when coil 20 is deenergized and one valve commences its seating stroke before the other there will be increasing magnetic reluctance in the magnetic circuit so that in rapid time the attracting force of the flux density will be reduced to a point where it is overcome by the return spring force. With the mass of each actuator and ball cage assembly essentially rendered static by the lip stops, the biasing force of the load springs will continue to push their respectiv poppet balls into their seats. The balls return to their seats under rotary and free floating action and self-center themselves in their seats. It can thus be clearly seen that the movement of one armature whether moving toward or away from, its adjacent pole face exerts an influence on the other armature because they are magnetically interlinked.
In another embodiment of this invention the valve assembly has a magnetic circuit, as is schematically illustrated in FIG. 4, incorporating a pair of armatures 101 and 103 which, rather than being in coplanar relationship as in the case of the embodiment shown in FIG. 3, are arranged in parallel relationship. Between armatures 101 and 103 is a primary core 112 encircled by an electrical coil 110 whose outer periphery is adjacent a pair of secondary cores 114 and 116. Secondary cores 114 and 116 are spaced equidistantly from primary coil 112 and the opposing ends of the three cores serve as pole faces. Armature 101 is positioned adjacent one set of pole faces while armature 103 is positioned adjacent the other set of three pole faces characterized by the opposite ends of the cores. By this arrangement a first magnetic flux loop 117 is constituted by, as shown by the arrows and dash line, primary core 112, secondary core 114 and portions of both armatures 101 and 103. A second magnetic flux loop 119 is constituted by primary core 112, secondary core 116 and other portions of both armatures 101 and 103. By the symmetrical relationship of the components, armatures 101 and 103 will always be parallel with one another as they are being drawn by magnetic attraction as well as when they are being moved through their seating strokes. As compared to the embodiment of this invention illustrated in FIG. 3, the armatures and therefore valves may be further separated from one another which may be an advantage from either safety or packaging requirement standpoints.
In another embodiment, as shown in FIG. 5, the valve assembly has amagnetic circuit including a pair of solenoid coils 131 and 133 encircling a pair of magnetic cores 135 and 137, respectively, that are of equal length and parallel to one another. The opposing ends of cores 135 and 137 serve as pole faces and are positioned adjacent armatures and 147 which, as in the above case, are aligned parallel with one another. When the coils are energized a single magnetic flux loop 139 results as indicated by the arrows and dash line.
It should be noted that the particular magnetic circuit embodiments as illustrated and described in conjunction with FIGS. 3, 4, and 5, are functionally interchangeable and the use of any one of these circuits would permit the advantages of this invention to be realized.
1. A multiple valve assembly for magnetically actuating at least two valves substantially simultaneously to and from their valve seats comprising;
a support structure,
at least two valves connected to the support structure,
at least one electromagnetic core having spaced pole faces afiixed to said support structure,
at least two armatures, each connected to a respective one of said valves oriented opposite each of said pole faces, the armatures being movable between valveclosed and valve-opened positions in response to activation of said core, and
a magnetic circuit including said core and said armatures for magnetically interlinking the armatures so that when the circuit is energized the resulting movement of one of the armatures influences the motion of the other armature so that substantially simultaneous valve motion is achieved.
2. The invention according to claim 1 further comprising a first return spring positioned between an interior wall section of said support structure and being connected to each armature for biasing each valve toward its valveclosed position.
3. The invention according to claim 2 wherein the spring is slidable in a recess formed in the wall section of said support structure, the recess forming a guideway so that the valve can be moved substantially axially.
4. The invention according to claim 2 wherein the valves are poppet balls retained in a tubular cage depending from said armatures, and
retaining means in said cage is provided for allowing each ball to become freely rotatabe and self-center- 5. The invention according to claim 4 wherein the retaining means for each ball comprises a turned-in lip at the base of said tubular cage whose diameter is smaller than the ball diameter, and
a second return spring connected at its opposite ends to the armature, the second spring contacting said ball opposite said retaining means to bias the ball downwardly against the lips so that the ball is freely rotatable between the lips and second spring.
6. The invention according to claim 5 further comprising stop means formed in said wall section of said support structure for stopping the motion of the armature and preventing its mass from impacting against the ball and its seat.
7. The invention according to claim 1 wherein the electromagnetic core is C-shaped and includes a pair of core arms and a base encircled by an electrical coil said magnetic circuit further including a flux bridge positioned between the core arms whose ends and the ends of the flux bridge act as pole faces, and
7 8 the armatures are connected to each of said valves and a second magnetic flux loop with the other secondary positioned in coplanar relationship, with one armacore, the primary core and other portion of both ture bridging a pole face on one core arm and a first armatures. portion of the flux bridge and the other armature References Cited bridging the pole face on said other core arm and 5 UNITED STATES PATENTS the other portion of the flux bridge.
8. The invention according to claim 1 wherein the elec- 215051849 5/1950 Bevls et a1 335*267 tromagnetic core is a primary core encircled by an elec- 2700374 1/1955 Jacobsen 137596-17 XR trical coil, said magnetic circuit further including a pair 2'828936 4/1958 Hales, of secondary cores at the outer periphery of said coil 10 t 2:5; 3
parallel to and spaced equidistantly from the primary core, the ends of all the cores forming a series of pole faces, and wherein HENRY T. KLINKSIEK, Pnmary Examiner the armatures opposite said pole faces form a first US Cl XR magnetic flux loop with one secondary core, the pri- 15 mary core and portions of both armatures and form 251-86; 335-265, 267