US3515160A - Multiple input fluid element - Google Patents

Description

June 1970 K. w. COHEN 3,515,160

MULTIPLE INPUT FLUID ELEMENT Filed Oct. 19, 19s? Li? FIG. IB

OUTLET O T EXHAUST E 44 K42 54) 48%LL56 qINLET 64 f SUPPLY INLET FIIG. 2'

EXHAUST INVENTOR.

KENNETH W. COHEN BY A FLUIDILETIS T I United States Patent 3,515,160 MULTIPLE INPUT FLUID ELEMENT Kenneth W. Cohen, Chesterland, Ohio, assignor to Bailey Meter Company, a corporation of Delaware Filed Oct. 19, 1967, Ser. No. 676,440 Int. Cl. F15c 1/16 US. Cl. 13781.5 5 Claims ABSTRACT OF THE DISCLOSURE A pure fluid device for accepting multiple fluid input signals and supplying a single output signal of a maximum predetermined flow level, which flow is independent of the number of inputs present and the flow level of the various input signals. A vortex chamber consisting of tangential inlets and a flow barrier which provide decoupling of the input signals, and a vent which exhausts to atmosphere the input fluid which is in excess of the maximum predetermined output flow level.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates generally to pure fluid devices requiring no moving mechanical parts for the operation thereof, and more specifically, relates to a fluid vortex device capable of isolating multiple fluid inputs and responding to said inputs by providing an output fluid flow signal of a predetermined value.

Description of the prior art The application of pure fluid devices as reliable, inexpensive circuit elements is not without operational disadvantages. The complexity of circuits utilizing pure fluid devices is a result of the necessary inclusion of decoupling circuits between inputs feeding a common fluid device and the individual element design required to insure impedance matching of mated fluid devices.

SUMMARY OF THE INVENTION The multiple inlet fluid element which is the subject of the invention consists of fluid inputs connected to fluid inlets located tangentially at the circumference of a cylindrical vortex chamber. A uni-directional vortical flow is established in the vortex chamber and a portion of said flow passes through a pre-sized fluid outlet to establish a control signal input to a fluid amplifier.

The inlet fluid flow remaining in the vortex chamber after the output control pressure signal is established is directed to a vortex vent located in an end wall of the vortex chamber by a flow barrier extending from a side wall of said chamber. This uni-directional flow pattern and flow barrier prevent fluid feedback through an inlet which could result in the unstable operation of a fluid device connected to said inlet. The vortex vent, in addition to providing over-pressure protection of the output fluid amplifier by venting excess fluid flow, also isolates the inlets of the fluid input element from disturbances occurring in the output fluid amplifier.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1A illustrates a plan view of one form of a fluid element constructed in accordance with the invention.

FIG. 1B illustrates a side view of the device of FIG. 1A.

FIG. 2 illustrates a plan view of the device of FIG. 1A driving a conventional fluid amplifier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1A and IE, I show one embodiment of a pure fluid element constructed in accordance with this invention and referred to by reference numeral 10. Fluid element 10 comprises plates 12 and 14 as depicted in FIG. 1B. A fluid passage configuration 16 is formed in plate 14 by molding, casting, milling, etching or other techniques capable of providing necessary passages and cavities of the element. The fluid passage configuration 16 comprises a cylindrical vortex chamber 18, a circular vent 20 located at the center of an end wall of said vortex, a flow arrestor 21 extending from the side wall of the vortex chamber to a position adjacent to circular vent 20, multiple fluid inlets 22, 24 and 26 connected tangentially to the circular circumference of said vortex chamber, and a fluid outlet 28 also connected tangentially to said vortex chamber. Plate 12 is designed to cover plate 14, both plates being sealed fluid-tight, one to the other, by mechanical, adhesive or other suitable means. For the purpose of clarity, plates 12 and 14 are shown to be composed of a transparent material; however, it should be understood that any material compatible with the working fluid may be used in the con struction of the fluid element 10. The fluid involved in the present application may be air or any other suitable gas; and, in some cases, liquid.

The operation of the fluid input element 10 is explained with reference to FIG. 2 wherein said fluid input element drives a conventional OR/NOR fluid amplifier 40.

The fluid inlets 22, 24 and 26 of fluid input element 10 are suitably connected to separate sources of fluid power, such as the outputs of OR/NOR fluid amplifiers (not shown), by means of conduits 32, 34 and 36 respectively. The fluid from each source enters vortex chamber 18 tangential to the wall of said chamber and creates vortical flow in a clockwise direction at the circumference of said chamber. Due to the physical arrangement of the multiple, tangential fluid inlets and the eifect of flow diversion caused by flow arrestor 21, a unidirectional fluid flow is established which prevents fluid feedback or interference between the various fluid inlets. The need for the intermediate de-coupling circuits required in conventional fluid input circuits to prevent erroneous switching and instability of a fluid inlet device is eliminated by the integral de-coupling feature of my fluid input element. Furthermore, the number of fluid inlets which can be accommodated by my device is limited solely by the physical size of the vortex chamber 18.

When pressure signals enter vortex chamber 1 8 through said inlets, the vortex movement of fluid within the chamber starts to provide a pressure build-up in a pressure impedance passage 28 which, in turn, supplies a limited control pressure signal to OR/NOR fluid amplifier 40 through conduit 42.

The fluid passage configuration 44 of said fluid amplifier is comprised of an interaction region 46, a supply fluid inlet 48, two fluid outlets 50 and 52, two control stream inlets 54 and 56, and two exhaust ports 58 and 60. A suitable fluid source is connected to supply fluid inlet 48 by means of conduit 64. The fluid passage configuration 44 of an OR/NOR amplifier locates a flow divider section 62 such that, under operating conditions wherein the fluid pressure in control inlets 54 and 56 is zero, the supply fluid entering inlet 48 will be diverted, in total, through fluid outlet 50. This conditin will remain until a control pressure is established in conduit 54 which is of suflicient magnitude to trigger the flip-flop operation of amplifier 40 and causes the supply fluid to pass through outlet 52. At such time when said control pressure in conduit 54 falls below a predetermined magnitude, the amplifier 40 will assume its mono-stable condition wherein the supply pressure will exit through outlet 50. Further discussion of the construction and operation of amplifier 40 will not be pursued as this device is well known to those skilled in the art. The application of an OR/ NOR amplifier is arbitrary as any conventional fluid amplifier could be substituted as the driven element in this discus- SlOIl.

Assume, for the purpose of explanation, that the operation performed by the output signal of amplifier 40 is to be initiated when one or more input pressure signals to input device attains a predetermined level. The fluid pressure developed in vortex chamber 18 is applied as a control pressure to amplifier 40 after having passed through the restrictor 28 which is sized so as to provide a constant level switching signal to driven element 40 regardless of the number of input signals applied to fluid input element 10'.

Assuming air to be the fluid, excess air, the air remaining in vortex chamber 18 after suflicient pressure is established in restrictor 28 to trigger driven device 40, is diverted to vortex vent 20 by means of flow arrestor 21 and subsequently vented to atmosphere. Vortex vent 20, in addition to providing over-pressure protection for driven element 40, prevents aspiration of air from fluid inlets 22, 24 and 26 by providing an available source of air from the atmospheric vent 20.

The aspiration of air through restrictor 28 is the result of so-called boundary layer theory, or the Coanda effect, which exists in the fluid outlet of the driven device 40 to maintain supply fluid at a switched outlet. The boundary layer theory, which pertains to a vacuum condition existing between the power fluid and the wall of the fluid out- 5 let, is well known to those skilled in the art of fluid devices. The presence of this condition results in the drawing or aspiration of air from the fluid input element 10 through restrictor 28 to driven device 40. In the absence of the atmospheric air reference source provided by vent 20, air would be drawn from the fluid devices connected to inlets 22, 24 and 26. This undesirable situation could result in unstable operation conditions of said fluid devices and possible erroneous switching thereof. Therefore, the presence of an atmospheric air source at vent 20 prevents the aspiration of air from the fluid sources connected to the inlets of fluid input element 10'.

Still another function of said vent is to attenuate any pressure disturbances traveling from driven device 40 to input element 10. The vortex vent 20 will cause said disturbances to dissipate to atmosphere through the vent, thus isolating the fluid inlets of element 10 from said disturbances and preventing said disturbances from affecting the stability of the fluid devices connected to the in- 1. A fluid decoupling device comprising:

a cylindrical vortex chamber defined between a pair of end walls, one of the end walls having a centrally located vent;

a plurality of fluid passages communicating with said vortex chamber, each of said passages extending tangentially to the circumferential periphery of said vortex chamber, one of said passages forming a fluid outlet sized to transmit a predetermined maximum flow from said vortex chamber, the remaining said passages forming fluid inlets being adapted to concurrently supply power fluid for vortex rotation; and

means, within said vortex chamber, for directing the flow in excess of the predetermined maximum away from the fluid outlet and through the centrally located vent to prevent both fluid feedback to the fluid inlets and interference between the fluid inlets and outlets.

2. The fluid decoupling device of claim 1, wherein said flow directing means is integrally formed in the pair of end walls.

3. The fluid decoupling device of claim 1, wherein said flow directing means includes a member extending from the side wall of said vortex chamber to a location adjacent to the centrally located vent, said member being disposed to direct the excess flow to the centrally located vent.

4. The fluid decoupling device of claim 3, wherein said member is arcuate in shape to provide a smooth transition for vertical flow from a location proximate to the fluid outlet to the centrally located vent.

5. The fluid decoupling device of claim 4, wherein said member is integrally formed in one of the end walls and transversely extends to the other end wall.

References Cited UNITED STATES PATENTS 3,193,197 7/1965 Bauer 13781.5 XR 3,207,168 9/1965 Warren 137-81.5 3,208,462 9/1965 Fox et a1. 13781.5 3,208,463 9/1965 Hurvitz 13781.5 3,216,439 11/1965 Manion 13781.5 3,238,960 3/1966 Hatch 13781.5 3,368,577 2/1968 Otsap 137-81.5 3,395,719 8/1968 Boothe et a1. 137-81.5 XR

SAMUEL SCOTT, Primary Examiner

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