US3712320A - An annular fluidic control device - Google Patents

An annular fluidic control device Download PDF

Info

Publication number
US3712320A
US3712320A US00138908A US3712320DA US3712320A US 3712320 A US3712320 A US 3712320A US 00138908 A US00138908 A US 00138908A US 3712320D A US3712320D A US 3712320DA US 3712320 A US3712320 A US 3712320A
Authority
US
United States
Prior art keywords
fluidic
aperture
members
disc
manifold body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00138908A
Other languages
English (en)
Inventor
T Jansen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pitney Bowes Inc
Original Assignee
Pitney Bowes Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pitney Bowes Inc filed Critical Pitney Bowes Inc
Application granted granted Critical
Publication of US3712320A publication Critical patent/US3712320A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15C—FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
    • F15C5/00—Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/206—Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/212—System comprising plural fluidic devices or stages
    • Y10T137/2125—Plural power inputs [e.g., parallel inputs]
    • Y10T137/2142—With variable or selectable source of control-input signal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/206—Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/2224—Structure of body of device
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/877—With flow control means for branched passages
    • Y10T137/87885—Sectional block structure

Definitions

  • This invention relates to fluidic apparatus.
  • the invention relates more particularly to an improved arrangement of a fluidic apparatus.
  • a fluidic device as is well known, comprises a means for defining a carrier fluid flow channel and a channel for a control fluid which operates on the carrier fluid to provide amplification or switching.
  • a plurality of such fluidic devices have been arranged in a single body to form a fluidic apparatus.
  • the apparatus includes inlet and outlet couplings to the various fluidic devices as well as intercoupling between the devices of the apparatus.
  • the fluidic devices are generally formed in a plastic material which exhibits a shrinkage characteristic. This characteristic can differ in magnitude over the cross-sectional area of the apparatus and results in varying operating characteristics for similar fluidic devices of the apparatus. Additionally, this nonuniform shrinkage undesirably alters alignment and sealing between components of the device. Furthermore, the relatively large dimensions of a body of this configuration which incorporates a large number of fluidic devices necessitates the establishment of flow paths between devices within the body which are relatively long and which undesirably increase the response time of operation of the devices.
  • a carrier gas inlet manifold which communicates with one or more of the devices in the apparatus.
  • the plurality of devices in a parallelpiped arrangement deriving carrier gas from a common inlet manifold has resulted in the spacing of the devices along a length of the body and contributes to an apparatus having a form factor which provides an apparatus packing density less than is desirable.
  • Another object of the invention is to provide a fluidic apparatus having a plurality of fluidic devices and which is configured to enhance the operating characteristics and to reduce the fabrication costs of the ap paratus.
  • Another object of the invention is to provide a fluidic apparatus of reduced dimensions.
  • Another object of the invention is to provide a fluidic apparatus having enhanced response times.
  • a further object of the invention is to correct one or more of the above enumerated disadvantages in the operation and fabrication of a fluidic apparatus.
  • a fluidic apparatus comprises an annular shaped body which includes a centrally located aperture extending through a thickness of the body.
  • the body includes a plurality of fluidic devices formed therein and which are positioned about the aperture.
  • a flow channel means for each of the devices communicates between the aperture and an associated device while a gas flow manifold extends into the aperture and conveys a gas from a source to the flow channel means.
  • FIG. 1 is an elevation view of a fluidic apparatus constructed in accordance with features of this invention
  • FIG. 2 is an exploded view illustrating members of a fluidic apparatus body
  • FIG. 3 is an enlarged plan view of a portion of a fluidic device flow disc incorporated in an embodiment of this invention.
  • FIG. 4 is an enlarged sectional view of the fluidic apparatus of FIG. 1.
  • the fluidic apparatus is shown to include an annular shaped body 10 which comprises a plurality of annular shaped body members defining a plurality of fluidic devices.
  • FIG. 4 illustrates a two-tier body wherein each tier defines a separate array of symmetrically positioned fluidic devices.
  • Each body, or tier in a multi-tier apparatus comprises a circular shaped plastic flow disc 12 [FIG.
  • the flow disc 12 and the circuit disc 16 includes a plurality of apertures and transversely extending grooves which define desired flow paths for the fluidic devices.
  • a circular plastic disc 20 formed of Mylar for example and having a centrally located circular aperture 21.
  • Similar discs 22 and 24 are sandwiched between the circuit disc 16 and the gasket 14 and between gasket 18 and the circuit disc 16 respectively.
  • One or more assemblies of these body members are provided to form a second tier as illustrated in FIG. 4.
  • the body members are positioned about an elongated, annular-shaped manifold body 26 which provides a means for conveying a carrier gas from a source, not illustrated, to the fluidic devices of the apparatus.
  • the manifold body 26 includes a segment 27 of reduced outside diameter, a centrally located bore 28 and an aperture 30 extending transversely through a wall of the bore.
  • the aperture 30 communicates with an enclosed volume 31 formed by the segment 27 and the body members.
  • a flow stream of carrier gas which comprises air under pressure for example flows to the space 31 over an enclosed path defined by a plastic elbow 32, the bore 28 and the aperture 30.
  • This supply of carrier gas is filtered by a nylon screen 34 which extends into the bore 28 from a distal edge segment 36 of the body 26.
  • the filter screen includes a shoulder 38 which abuts the distal segment 36 of the body 26 and restricts further entry into the bore 28.
  • a press fit is provided between the elbow 32 and body 26 and a force exerted on a lower surface of the shoulder 38 by a shoulder 40 which is formed in the plastic elbow 32 secures the screen 34 in place.
  • the apparatus includes means for securing the body members in alignment and for mounting members to the manifold body 26.
  • This means includes upper and lower plates 42 and 44 respectively which are circular shaped and have apertures centrally located therein. Indexing pins 45 extend through alignment apertures 46 formed in the body members and through apertures formed in the upper and lower plates in order to provide alignment of the various members of the assembly. These apertures are preferably assymertically positioned about the manifold body in order to inhibit improper assembly of the body members.
  • the upper plate 42 is restrained by a shoulder 47 formed in the manifold body 26. A force is exerted against the lower surface of the plate 44 which secures and mounts the assembly to the manifold body 26.
  • a spacer body 48 and lock nut 49 which engages an exterior threaded surface 50 of the manifold 26.
  • a star washer 51 is located between the spacer 48 and locknut 49 and O-ring gasket 52 provides a leakproof seal between the manifold body 26 and the lower plate 44.
  • the flow disc 12 includes recesses formed in the surface thereof which when combined with a sealing gasket 14 defines a plurality of fluidic devices equally spaced about a longitudinal axis of the disc.
  • the fluidic devices illustrated in FIG. 2 and 3 are shown to be comprised of flowmode type amplifiers it is understood that other fluidic devices, as for example wall attachment and proportional amplifier flip-flop and oneshot devices, can equally well be employed in accordance with the general features of this invention.
  • the flow-mode turbulence amplifier device is shown to include a carrier gas emitter channel 62 for conveying carrier gas to a control chamber 64.
  • Positioning of the flat gasket surface 14 on the disc 12 encloses grooves formed in the disc 12 thereby establishing channels and chambers.
  • Carrier gas flowing from the chamber 64 will flow to a collector groove 66 and port 67 and then to an outlet of the device or through vent channel 68 and 70 to vent ports 72 and 74 respectively.
  • Control gas inputs are provided through control gas grooves 76,78,80 and 82 and their associated ports 77, 79, 81 and 83 respectively.
  • the carrier gas for each fluidic device will flow from the manifold aperture 30 (FIG. 4) into the space 31 through a circular manifold formed by a ridge 84 and gasket 14 and through an inlet port 85 to the emitter channel 62.
  • Gasket 15 includes apertures 86 which index with those ports of a fluidic device which are utilized in a circuit while the surface of the gasket seals off the unused ports.
  • the discs 20,22, and 24 include apertures 87 which index with the disc ports and apertures 86. These discs may be interchangeably employed by establishing apertures 87 at each port location on a disc 12.
  • intercoupling means between the fluidic devices in a flow disc 12 is provided in part by the apertures 87 formed in the Mylar discs 20 and 22, the aperture 86 formed in the rubber gasket 14 and aperture 88 formed in the metal disc 16.
  • the apertures in the discs 20 and 22 and in the rubber gasket 14 index to provide a flow path between a particular groove of a device and conductive path formed in the metal disc 16.
  • the fluidic device referenced generally as 90 will include a collector groove which indexes with apertures in the disc 20, the
  • a flow path 92 is defined in the disc 16 between the aperture indexed with the collector groove of the device 90 and an aperture indexed with a control groove of another device 94 located on the disc 12.
  • the outlet of the fluidic device 90 is employed as a control input to the device 94.
  • Various other circuit arrangements can be readily provided by establishing the desired flow paths in the disc 16 and by providing proper indexing holes between the desired control and emitter grooves in the flow disc 12.
  • FIG. 4 illustrates this form of coupling arrangement.
  • a collector groove outlet port of a fluidic device indexes with with a port 102 in the circuit disc 16.
  • a channel is formed in the circuit disc 16 between the port 102 and a second port 104 which indexes with a channel 106 extending in an axial direction and formed in the thickness of a second flow disc 108.
  • This channel 106 I indexes with a control groove inlet port 109 for a fluidic device formed on the flow disc 108 in a second tier.
  • Another control groove port 110 of the dame device is shown to index with an aperture 111 in a metal disc 112 and a channel in the disc 112, not shown, couples the aperture 111 to an aperture 114 which indexes with an inlet tubulation 116.
  • a control gas comprising a control input to a fluidic device is supplied from a source not shown to the tubulation 116 through a flexible plastic tubing 118.
  • Through channels, not shown, are also formed by the body members for coupling the inlet tubulation directly to devices of the lower tier.
  • One or more external control sources can be coupled to one or more control inlet tubes.
  • an outlet tubulation 120 indexes with an aperture 122 for a channel in the circuit disc 117.
  • the channel not shown, communicates with a collector groove of a fluidic device.
  • the gas outlet flow from he fluidic device is then coupled through a tubulation 124 or alternatively a plug-in coupling, not illustrated, to a utility device.
  • a plurality of such outlet tabulations can also be provided.
  • Through channels, not shown, are also formed by the body members for coupling the outlet tubulation directly to devices of the lower tier.
  • vent ports 72 and 74 are provided in a flow disc for each of the fluidic devices. These vent ports are formed in the peripheral surface of the flow disc 12. These vents, as indicated, communicate with the channels 68 and 70 respectively and provide a venting path to atmosphere for a device.
  • a screen 130 is formed about the peripheral surface of the apparatus body. The screen 130 extends between the upper and lower plates 42 and 44 and abuts against the peripheral surfaces of the various apparatus members. The screening is formed of a suitable fine mesh to inhibit backflow of particles and maintain an unrestricted gas venting flow path.
  • a suitable screen is formed for example of 160 X 160 stainless steel mesh or a Monel plain weave.
  • the screen 130 is itself protected from deformations by a second more coarse screen 132 which is positioned about it and which is weaved from polypropylene for example.
  • This screen is secured in position by O-rings 134 and 136 which are positioned over the outer surface of the screen and abut against the upper and lower surfaces 42 and 44 respectively.
  • Fluid under pressure flows from the manifold body 26 through the emitter channel 62 and forms a laminer jet which is directed into the axially aligned collector groove 66. Fluid thus flows through this channel to a second device or to an apparatus which is to be controlled or operated. Any simultaneous fluid flow in the interaction chamber 64 which does not flow into the collector groove 66 will leave the system via the venting channels 68 and 70 and the associated venting ports 72 and 74. In this mode of operation or condition, the fluid recovery pressure in the collector groove 66 will be relatively high.
  • a fluid pressure control signal is introduced through any one of the four control line ports 77,79,81 or 83 and their associated grooves 76,78,80 and 82 respectively.
  • an appropriate fluid pressure control signal is introduced through any one of these ports for example and against the side of the laminer jet, three significant changes occur.
  • the laminer jet issuing from the emitter groove becomes turbulent; secondly, the jet of fluid issuing from the emitter groove is caused to deflect to a substantial extent towards a side wall, the axis of this turbulent fluid flow in this case being deflected toward the left when an input is applied to the control port 77 for example; and thirdly, the deflected turbulent fluid stream effectively interacts with the side wall in flowing toward the venting ports 72 and 74 at the downstream end of the chamber 64. Most of the fluid flow during this turbulent mode of operation will exit through the venting ports 72 and 74 and only a relatively small amount will enter the collector groove 66. Thus, in this second operative mode or condition, the fluid recovery pressure in the collector groove 66 will be relatively low. As the fluid control signal applied to the control port 77 is terminated, the fluid flow in the chamber 64 will immediately return to its first or normal operative condition of laminer flow.
  • annular configuration of the fluidic apparatus results in uniform shrinkage of plastic flow disc members and a resulting uniform variation in the characteristics of all of the elements when such shrinkage occurs rather than an undesirable varying shrinkage. The alignment and seal between the members is thus maintained.
  • the annular configuration is particularly beneficial when photo-reducing the flow disc and other body members which are initially produced through large scale art work and are then reduced to smaller dimensions. Fringe effects and edge distortions occuring in lens systems employed for reducing this art work are substantially avoided with the circular configuration described.
  • the use of a single fastner which applies a uniform pressure throughout the body results in a more uniform structure and substantially reduces the fabrication costs by eliminating the need for many rivet connections as has been provided in the past.
  • the described fluidic apparatus is further beneficial in that the intercoupling paths between different fluidic devices in the apparatus is substantially reduced over prior arrangements by virtue of the configuration disclosed.
  • the reduction in these flow paths substantially reduces the response times of a system employing the fluidic devices.
  • the fluidic device illustrated in FIG. 4 and including the flow disc of FIG. 2 and 3 is particularly useful when intercoupled as a ring counter.
  • the uniform and symmetrical geometry of these devices positioned about a central axis contributes to the reduction in the length of flow path and renders this configuration particularly useful as a ring counter form of digital device.
  • a fluidic apparatus comprising:
  • a plurality of annular shaped body members each having a thickness thereof and including a centrally located aperture extending through the thickness of the member, said plurality of members including a flow disc having a plurality of grooves formed in a surface thereof, and a gasket having apertures for converting said grooves into channels and chambers and for providing input and output ports to said channels and chambers;
  • said manifold body defining a gas flow passage communicating between a gas source and each of said emitter channels for providing a gas supply input to said fluidic devices.
  • THe apparatus of claim 3 wherein means are provided for establishing flow paths between the devices in different tiers of said apparatus.
  • said manifold body is cylindrically shaped and includes an axially extending bore and a transversely formed aperture extending between the bore and an outer surface of said body for providing a fluid flow path through said bore to said aperture and through said aperture to said fluidic devices
  • said means for mounting said body members comprises first and second annular shaped plates each having apertures therein and through which said manifold body extends, said plates positioned on said body for positioning therebetween said plurality of annuarly shaped apparatus body members, and a locking means secured to said manifold body and establishing a force between said first and second plates.
  • said manifold body includes an externally formed threaded segment and said locking means comprises a means for engaging said threaded segment and for applying a force to said second plate.
  • sa1d manifold body includes a shoulder formed therein near a distal segment thereof for restricting motion of said first plate in an axial direction, a spacer body abutting against said second plate and means for forming a gas tight seal between said manifold body and said plate, and a nut engaging said thread and abutting against said spacer means for establishing a force against said second body.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Theoretical Computer Science (AREA)
  • Measuring Volume Flow (AREA)
  • Indicating Or Recording The Presence, Absence, Or Direction Of Movement (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
US00138908A 1971-04-30 1971-04-30 An annular fluidic control device Expired - Lifetime US3712320A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US13890871A 1971-04-30 1971-04-30

Publications (1)

Publication Number Publication Date
US3712320A true US3712320A (en) 1973-01-23

Family

ID=22484208

Family Applications (1)

Application Number Title Priority Date Filing Date
US00138908A Expired - Lifetime US3712320A (en) 1971-04-30 1971-04-30 An annular fluidic control device

Country Status (12)

Country Link
US (1) US3712320A (pt)
AU (1) AU456735B2 (pt)
BE (1) BE782826A (pt)
BR (1) BR7202640D0 (pt)
CA (1) CA945904A (pt)
CH (1) CH539209A (pt)
DE (1) DE2221191A1 (pt)
FR (1) FR2134680B1 (pt)
GB (1) GB1346962A (pt)
IT (1) IT955190B (pt)
NL (1) NL7205793A (pt)
ZA (1) ZA722838B (pt)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3786831A (en) * 1973-04-05 1974-01-22 Clippard Instr Labor Inc Valve with modular manifold body
US3815635A (en) * 1973-07-30 1974-06-11 Automatic Switch Co Temperature compensator device and fluidic assembly incorporating it
US6317977B1 (en) * 1998-10-26 2001-11-20 Smc Kabushiki Kaisha Manufacturing method for fluid passage forming member made of synthetic resin
US20090117009A1 (en) * 2007-11-02 2009-05-07 Richard Cote Multi-channel electronic pipettor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3507116A (en) * 1968-05-29 1970-04-21 Us Navy Flueric variable thrust injector
US3512558A (en) * 1967-04-21 1970-05-19 Pitney Bowes Inc Fluid control device
US3574336A (en) * 1968-12-26 1971-04-13 William P Kramer Lawn sprinkling apparatus
US3614964A (en) * 1969-09-16 1971-10-26 Sperry Rand Corp Clock pulse generating system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3512558A (en) * 1967-04-21 1970-05-19 Pitney Bowes Inc Fluid control device
US3507116A (en) * 1968-05-29 1970-04-21 Us Navy Flueric variable thrust injector
US3574336A (en) * 1968-12-26 1971-04-13 William P Kramer Lawn sprinkling apparatus
US3614964A (en) * 1969-09-16 1971-10-26 Sperry Rand Corp Clock pulse generating system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Langley, R. F. and Schulz, P. B., Modular Pneumatic Logic Package, I.B.M. Tech. Dis. Bulletin, Vol. 6, No. 5, Oct. 1963. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3786831A (en) * 1973-04-05 1974-01-22 Clippard Instr Labor Inc Valve with modular manifold body
US3815635A (en) * 1973-07-30 1974-06-11 Automatic Switch Co Temperature compensator device and fluidic assembly incorporating it
US6317977B1 (en) * 1998-10-26 2001-11-20 Smc Kabushiki Kaisha Manufacturing method for fluid passage forming member made of synthetic resin
US20090117009A1 (en) * 2007-11-02 2009-05-07 Richard Cote Multi-channel electronic pipettor

Also Published As

Publication number Publication date
BE782826A (fr) 1972-10-30
NL7205793A (pt) 1972-11-01
ZA722838B (en) 1973-02-28
CA945904A (en) 1974-04-23
BR7202640D0 (pt) 1973-06-28
IT955190B (it) 1973-09-29
DE2221191A1 (de) 1972-11-09
GB1346962A (en) 1974-02-13
FR2134680B1 (pt) 1977-08-26
AU456735B2 (en) 1975-01-09
CH539209A (de) 1973-07-15
FR2134680A1 (pt) 1972-12-08
AU4168272A (en) 1973-11-01

Similar Documents

Publication Publication Date Title
US3570515A (en) Aminar stream cross-flow fluid diffusion logic gate
US3495608A (en) Fluidic elements and devices thereof
US3537466A (en) Fluidic multiplier
GB1488607A (en) Fluid flow control device incorporating silencing means using vortical flow patterns
US3610274A (en) Fluid logic circuit
US3015210A (en) Attitude control for high altitude missile
US3712320A (en) An annular fluidic control device
GB1071267A (en) Improvements in or relating to fluid vortex amplifiers
US3215162A (en) Bistable control valve
US3076473A (en) Program control devices for fluid apparatus
US3272470A (en) Fluid flow control device
US3937248A (en) Fluid flow control system employing a plurality of digital valve elements
US3272213A (en) Readout for vortex amplifier
GB1227788A (pt)
US3270758A (en) Fluid amplifiers
ES8200044A1 (es) Perfeccionamientos en aparatos distribuidores de fluidos a presion
GB2080495A (en) Seal for a balanced relief valve
GB1281657A (en) Fluid-pressure-responsive logical elements
US3385322A (en) And valve for fluid logic circuits
US3319926A (en) Multiple signal actuated diaphragm valve
US5107885A (en) Check valve
GB1376613A (en) Fluid diaphragm modulator
US3428065A (en) Feedback isolator
US3481352A (en) Fluid apparatus
US3425432A (en) Bistable fluid amplifier