US3823725A - Pneumatic control apparatus - Google Patents

Pneumatic control apparatus Download PDF

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Publication number
US3823725A
US3823725A US26800272A US3823725A US 3823725 A US3823725 A US 3823725A US 26800272 A US26800272 A US 26800272A US 3823725 A US3823725 A US 3823725A
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United States
Prior art keywords
pressure
conduit
automatic
manual
output
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Expired - Lifetime
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English (en)
Inventor
T Akiyama
R Fukuda
T Umeda
T Shiga
M Ando
N Wada
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Honeywell Inc
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Honeywell Inc
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Priority to JP5236171A priority Critical patent/JPS5419956B1/ja
Application filed by Honeywell Inc filed Critical Honeywell Inc
Priority to US26800272 priority patent/US3823725A/en
Priority to IT5140772A priority patent/IT960994B/it
Priority to DE2233761A priority patent/DE2233761A1/de
Priority to GB3276472A priority patent/GB1393260A/en
Priority to FR7225421A priority patent/FR2145662B1/fr
Application granted granted Critical
Publication of US3823725A publication Critical patent/US3823725A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • F15C4/00—Circuit elements characterised by their special functions
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06G—ANALOGUE COMPUTERS
    • G06G5/00—Devices in which the computing operation is performed by means of fluid-pressure elements
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S137/00—Fluid handling
    • Y10S137/90—Bumpless manual to automatic relays
    • 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
    • Y10T137/2278—Pressure modulating relays or followers
    • Y10T137/2365—Plural series units
    • 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
    • Y10T137/2278—Pressure modulating relays or followers
    • Y10T137/2409—With counter-balancing pressure feedback to the modulating device
    • Y10T137/2452—With counter-counter balancing pressure feedback

Definitions

  • ABSTRACT A pneumatic, proportional, integrating and 'diffezesitir ating control apparatus wherein a rate unit is interposed between the output of an automatic control unit I and a negative feed-back circuit and wherein an automatic-manual transfer switch is employed to bypass and cut out the effect of the'rate unit at the time of manual operation and to reactivate the rate unit at the time of automatic operation.
  • This control apparatus is constructed so that the transfer switch will operate 2 Claims, 12 Drawing Figures mil/1.).
  • the present invention generally relates to a pneumatic control apparatus comprising an automatic control unit, a manual control unit and an automaticmanual transferring means, and more particularly to a novel manual to automatic transfer means for the pneumatic control apparatus for effecting a bumpless transfer from manual control to automatic control without a conventional manual balancing operation, that is, a bumpless and balanceless manual to automatic transfer.
  • the conventional bumpless manual to automatic transfer is realized by means of a manual'balancing operation which adjusts an output of the automatic control unit to such an extent that its value is equal to an output of the manual control unit in manual control mode.
  • the present bumpless transferring from'manual-to automatic is made, Without the conventional manual balancing operation, by means of a balancing unit which acts to automatically make the output of the automatic control unit follow the output of the manual control unit in manual control mode.
  • the balancing unit of the bumpless manual to automatic transfer according to the present invention desirably has a high gain characteristic.
  • the present invention uses a pneumatic differential amplifier which is specially designed in order to obtain high gain.
  • Another object of this invention is to provide a new and improved pneumatic proportional integrating and differentiating control apparatus wherein a rate unit is interposed between the output of an automatic control unit and a negative feedback circuit associated therewith, and an automatic-manual transfer switchadapted to short circuit the rate unit at the time of manual operation and to close the rate unit at the time of automatic operation is constructed such that.
  • the transfer switch operates with alonger time than another automaticmanual transfer switches (which operate substantially instantaneouslY) when the operation is switched from manual to automatic operation, thus providing a bumpless and balanceless manual-automatic switching.
  • a pneumatic proportional integrating control apparatus comprising an automatic pneumatic control unit with reset means, a manual control unit and automaticmanual transfer means, said automatic-manual transfer means including abalancing unit of the high gain pneumatic differential'amplifier type, a first automatic: manual transfer switch included in an output conduit interconnecting the output of the pneumatic typeautomatic control unit and the output of the control apparatus, a second automatic-manual transfer switch included in a conduit interconnecting the output of the balancing unit and a reset capacitor of the pneumatic type automatic control unit, a conduit interconnecting one input of the balancing unit and the output of the pneumatic type automatic control unit, a conduit for transmitting to the other input of the balancing unit the output from the pneumatic type automatic control unit at the time of automatic control operation, whereas the outputfrom the manual control unit at the time of manual control operation, and a third automatic-manual transfer switch connected in a conduit leading to the output of the manual control unit, whereby, at the time of manual control
  • a pneumatic proportional integrating and differentiating control system which is provided by modifying above described pneumatic proportional integrating control system by adding a time delay transfer switch in a conduit connected in parallel with the rate unit of the pneumatic control device.
  • FIG. la shows a pneumatic circuit of one embodiment of the invention.
  • FIG. 2 is.a sectional view showing a unique pneu- I matic operational amplifier unit utilized in this invention
  • FIG. 3 shows a longitudinal section of a pneumatic switch
  • FIG. 4 shows a longitudinal section of a'pneumatic l:l relay
  • FIG. 5 is a graph to explain the operation of the pneumatic relay shown in FIG. 4;
  • FIG. 6 diagrammatically shows a rate unit
  • FIG. 7 is a longitudinal sectional view of a balancing unit
  • FIG. 8 is a perspective view of an orifice and an oriflee plate utilized in the balancing'unit shown in FIG. 7;
  • FIG. 9 is a plot showing an input-output characteristic of the balancing unit shown in FIG. 7.
  • FIGS. 10a and 10b show the manner of switching the operation mode betweenthe manual mode and the automatic mode.
  • FIG. 1a showing a diagrammatic arrangement of one example of a, PID, proportional integrating and differentiating pneumatic control apparatus embodying theinvention
  • the control apparatus is illustrated as comprising a pneumatic operational amplifier unit 45 including a nozzle-flapper mechanism having a flapper 68, a pair of air inlet ports 86 and 87, a pair of feedback air inlet ports 88 and 89, and a nozzle 69 for detecting and converting the displacement of a balancing beam 67 into a corresponding output air pressure; a screw throttle R acting as a proportional band adjusting means on the input side; cylindrical fixed throttle R ;transfer switch SW restrictions R and R, which constitute a proportional band adjusting first pneumatic relay 41 and for preventing the leakage of the air pressure from the rate unit to the proportional band adjusting means on the feedback side; a rate off switch 37; a pilot valve 48; a manual control unit 49 for generating desired manualoperating pressure and for following-up the automatic operating pressure at the time of
  • the rate unit 46 comprises a bellows unit 38, a rate throttle R and a rate capacitor C Like the reset throttle R the rate throttle R takes the form of a nozzle-flapper type variable throttle valve. As shown in FIG. la and FIG.
  • the reset throttle R comprises a nozzle I43, a-flapper I45 fulcrumed by a shoulder of the nozzle, a leaf spring 146 for urging the flapper and means for adjusting the inclination of the flapper which are contained in a casing 144, and an air inlet port 141 and an air outlet port 142.
  • the means for adjusting the inclination of the flapper or the means for adjusting the degree of throttling comprises an eccentric cam 147, which is operated by a knob, not shown, a cam follower 149 and an adjustable screw 148 for connecting one end of the flapper 145 to cam follower 149.
  • the l:-l pneumatic relay 42 has the same characteristic as relay 4] and has a construction as shown in FIG. 4.More particularly, the interior of a casing 120 is divided into two air chambers 128 and 127 by means of a diaphragm 125 and a nozzle shaped discharge port 126 is provided for chamber 128.
  • An air supply conduit 122 is connected to the air chamber 128 via a restriction 123, whereas the outlet conduit 124 is connected directly to air chamber 128.
  • An air inlet conduit 12] is connected directly to the other air chamber 129.
  • the pneumatic operational amplifier unit 45 comprises a casing 57 which contains a pair of input pressure receiving chambers 51 and 52, a pair of feedback pressure receiving chambers 53 and 54, an input pressure receiving member'75 in the form of a bellows and partitioning chambers 51 and 52, a feedback pressure receiving member or bellows 76 partitioning chambers 53 and 54, and a balancing beam 67 connected to the respective movable ends of the pressure receiving members 75 and 76 so as to displace in response to the received air pressure signals.
  • Two pairs of cylinders 81, 82 and 83, 84 coaxial with the balancing beam 67 are provided in casing 57 along a common axis and these cylinders are vented to the atmosphere.
  • cylinders 82 and 83 are constructed integral and vented to the atmosphere through a vent passage 55. These cylinders have the same diameter D. Provision of the vented cylinders requires to hermetically seal all pressure receiving chambers. For this purpose it is advantageous to use rolling diaphragms 71, 72, 73 and 74 with their movable ends connected to balancing beam 67 and the stationary ends to the ends of the cylinders. Pistons 61, 62, 63 and 64 are disposed in respective cylinders. Each piston is connected to the balancing beam 67 such that its head alignes with one end of the corresponding cylinder when the balancing beam assumes a zero position so as to engage the corresponding rolling diaphragm.
  • the outer diameter of the pistons is important to improve the extent of off-set. As shown exaggerated in FIG. 2 the outer diameter d of piston 64 is smaller than another piston 63 opposing thereto. Another pair of pistons 61 and 62 are constructed to have the same outer diameter d which is equal to that of piston 63. For this reason, it is advantageous to form pistons 62 and 63 as an integral body, as shown in FIG. 2. Accordingly, cylinders 82 and 83 are also made integral.
  • balancing beam 67 The purpose of balancing beam 67 is to derive out the resultant displacement of a pair of pressure receiving members 75 and 76.
  • throttle R constituting the proportional band adjusting means on the input side is constructed to utilize, as the restricted air passage, a small gap existing between mating male and female screws.
  • the gap is used to act as a throttle.
  • the screw throttle R comprises a casing 101 provided with fe male screw 102 between an inlet chamber 106 and a discharge chamber 107, a male screw 103 having the same diameter and the screw threads of the same pitch as the female screw 102, and an adjusting member for the male screw having an O-ring.
  • This screw throttle R can be manufactured very easily and can be adjusted readily.
  • FIG. 3 shows a modified switch SW which is constructed to be leak proof. Except for the manual operation, the construction of this switch is substantially the same as that of automatic-manual transfer switches SW SW and SW;,.
  • the proportional band adjusting circuit on the feedback side is a pressure dividing circuit including a series throttle R and a parallel throttle R,. It is necessary to use throttles having the same characteristic. In this ex ample, both throttles are shown as needle throttle valves, throttle R being fixed whereas throttle R being adjustable. For this reason, the operating knob of the adjustable throttle R, is provided with a suitable scale, not shown. Utilization of a pressure dividing circuit constituted by throttles of the same characteristic greatly improves the linearity of the pressure dividing input output characteristic assumes a line B instead of a line A which corresponds to the one to one ratio. This off-set is caused by the construction of the pneumatic nate the off-set with a single pneumatic relay. More particularly, as shown in FIG.
  • the 1:1 pneumatic relay is provided with an air inlet port 122 and an air discharge port 126 opposing to one side of a diaphragm 125.
  • the internal diameter and the external diameter of the discharge pipe are denoted by X, and X respectively
  • the effective area of the diaphragm on the side of the air chamber 128 is decreased by 1r/4 (X,+X /2)
  • the 1:1 characteristic curve A will be shifted to curve B as shown in FIG. 5.
  • the 1:] pneumatic relay 41 should be included in the reset circuit so that its air chamber 129, is connected to reset capacitor C, in order to prevent the air leakage from the reset circuit to the proportional adjusting circuit on the feedback side. If there is some cause that causes the feedback circuit to produce an error of some type, the off-set eliminating function of the improved pneumatic operational amplifier unit 45 would be nullified. For this reason, 1:1 pneumatic relay 42 is included in the negative feedback circuit to oppose the 1:1 pneumatic relay 41 of the same characteristic and included in the reset circuit-acting as the positive feedback circuit thereby producing an off-set free differential output.
  • the l:l pneumatic relay 41 can also be used for the control device including a rate unit for the purpose of preventing the air leakage from the rate circuit to the proportional band adjusting circuit on the feedbackcircuit.
  • FIG. 7 The detail of the constructionof the balancing unit 47 and its orifice portion are shown in FIG. 7 and FIG.
  • the balancing unit 47 is a pneumatic amplifier of differential operation type which'acts to produce an output pressure signal proportional to' a differential pres- 160 so connected as to be actuated by the beam of the pressure receiving means, a nozzle 161 mounted on a base block 151 so as to face to the flapper 160, spaced therefrom by a distance indicated 'as Xmm, an air passage means 172 for supplying filtered air of a predetermined pressure Ps to the nozzle 161, a restriction 178 of orifice type inserted in the air passage means, and an output conduit 173 for deriving a nozzle back pressure Po from the down stream side of and adjacent to the orifice 178.
  • the flapper 160 and the beam of the pressure receiving means are constructed integral as shown in FIG. 7.
  • the air passage means includes the conduit 172, air passages 191, 197, 184 and 17.1 and'a chamber 185.
  • the passages 191 and 197 are formed in a plug 175, the passage 184 is formed in aclamping member 176.
  • Passages 171 and 185 are formed in the base block 151.
  • the plug 175 has an ori- 6 fice mounting chamber in which the orifice plate 177 is clamped by the clamping member 176.
  • the clamping member 176 is provided with the passage 184 of axial bore type and the inner end thereof is provided with several radial ducts 183 for deriving the nozzle back pressure Po.
  • The'clamping member 176 has an engaging portion having a diameter which is the same as the inner diameter of the orifice mounting chamber formed in the one end of the plug 175 so that clamping of the orifice plate 177 is achieved.
  • the chamber 185 is formed in the base block 151 by forming a bore therethrough, plugging the plug 175 into one end of the bore and sealing the other end of the bore by means of a metal sealing ball 186.
  • O-rings 196 are provided to surround the plug 175 to interrupt communication between passages 191 and 192 and between passage 191 and the atmosphere.
  • the passage 192 is formed in the plug so as to derive the nozzle back pressure.
  • the output conduit 173 is formed in the base block 151 coaxial with the passage 192.
  • the plug 175 is received in the base block 151 by screw threads 193 and 194. Communication between chamber 185 and passage 192 is interrupted by the engagement between the base block 151 and plug 175 at 196.
  • the pressure receiving means comprises a pair of pressure receiving chambers 154 and 155, a pair of pressure receiving members 156 and 157 in the form of diaphragms for defining the pressure receiving chambers 154 and 155, respectively, a member 158 engaging these diaphragms for transmitting the displacement thereof to a flapper 160, a supporting member 162 in the form of a leaf spring and a screw 163 for supporting the end of the flapper opposite to the opperating end 163, coil springs 164 and an adjusting screw 165 for imparting a'biasing force of the proper magnitude to the flapper, clamps 159 for the diaphragms'and a pair of air passages 152 and 153 formed inthe base block and
  • the pressure receivingchambers 154 and 155 are constructed identically so as to make equal the effective areas of thediaphragms.
  • the displacement (in the vertical direction as viewed in FIG. 7) of the flapper 160 is proportional to the difference between two input air pressure signals P and P and the direction of the displacement is determined by the sign of the difference ('P,, P In the example shown in FIG. 7', P P the flapper 160 will be displaced up wardly, whereas if P P the flapper will be displaced downwardly.
  • the output air pressure signal P (kg/cm) from the balancing unit 47 of this; .invent ion will vary as shown by a graph of FIG.
  • the abscissa represents the distance X (mm) between'the nozzle and the flapper and the ordinate represents the output air pressure signal P (kg/cm P shows the pressure of the air supplied to thenozzle which is supplied from a source of clean air at 1.4 (kg/cm' for example.
  • the origin 0 (kg/cm) represents the atmospheric pressure.
  • the balancing unit can produce output signals of sub- 7 atmospheric pressure thus increasing the gain as well as the orifice for utilizing the decrease in the air pressure caused by the eddy current of the air produced near the orifice as the output air pressure signal.
  • the construction of the nozzle is advantageous in that it is possible to select any desired value for the distance between nozzle 161 and orifice 178. We have confirmed by experiment that the distance between the nozzle 161 and the orifice 178 does not affect the output characteristic.
  • bumpless and balanceless switching of the operation modes between a, PI, proportional integrating or, PID, proportional integrating and differentiating control unit with an automatic reset, and a manual operator or a manual control unit can be made in the following manner.
  • FIG. lb The pneumatic circuit of the novel pneumatic control apparatus for the manual control is shown in FIG. lb in which the output OUT from the control apparatus is represented by the output pressure P of manual unit 49. More particularly, for the manual control, since transfer switch SW, is positioned to connect conduit 14 with conduit 15 so that the manual operating pressure P from the manual unit 49 is applied to the pressure receiving chamber of the pilot valve 48 via conduit 14, switch SW conduit 15 and conduit 11 with the result that the pilot valve 48 will provide an output pressure P to the output 40 of the control apparatus via conduit 12. For convenience, it is now assumed that the pilot valve 48 has an input-output ratio of 1:].
  • the transfer switch SW Since the transfer switch SW, is positioned to interrupt the communication between conduits 9 and 10, the manual operating pressure P from manual unit 49 is also applied to one of the pressure receiving chambers of the balancing unit 47. Since the transfer switch SW is ON to interconnect conduits l8 and 3 2, the output pressure P from the balancing unit .47-is applied to the reset pressure receiving chamber 54 of the pneumatic operational amplifier unit 45 via conduit 18, transfer switch SW conduit 32, relay 41 and the pressure dividing circuit for the proportional adjustment. As a result, the operational amplifier unit 45 produces an output P,,* for the manual operation which is applied to the other pressure receiving chamber of the balancing unit 47 and to the other feedback pressure receiving chamber 53 of the pneumatic operational amplifier unit 45 via the negative feedback circuit as shown in FIG. 2.
  • the balancing unit 47 has a pair of pressure receiving chambers 154 and 155 so as to produce the output air pressure P by the cooperation of flapper 160 displaced by the pressure differential of two input signals applied to the pressure receiving chambers 154 and 155, and nozzle 161 confronting the flapper 160.
  • the output pressure P varies as shown in FIG. 9 as the gap X" between the nozzle and flapper varies. Since gap X is varied in proportion to the differential pressure between two signals, it is possible to produce output signal P proportional to the difference between said two input signals.
  • the balancing unit 47 acts as a differential type pneumatic amplifier unit, and the gain and linearity of the input-output characteristic are improved, as shown by FIG. 9, by the unique nozzle shown in FIGS. 7 and 8. As is well known in the art, with the conventional nozzle it is-impossible to produce a subatmospheric output (shown below the abscissa of FIG. 9).
  • switch operating pressure is supplied from a source of compressed air P to immediately switch ON the first automatic-manual transfer switch SW, and switch OFF the second automatic-manual transfer switch SW
  • the third automatic-manual transfer switch SW is switched from On to OFF with a definite delay time which is determined by the time constant circuit comprising the volume C, of the pressure receiving chamber of switch SW, and the restriction'R in conduit 19 leading to the pressure receiving chamber. This time delay is important to provide the bumpless transfer from manual to automatic of the pneumatic control apparatus with differential action, that is the novel pneumatic PID control apparatus.
  • FIGS. a and 10b show the bumpless switching from manual to automatic. In this manner, according to this invention, even in the presence ofa deviation, it is possible to provide bumpless transfer from manual to automatic by a single step operation, that is without the necessity of any balancingoperation.
  • a pneumatic proportional integrating and differentating control apparatus comprising a pneumatic control unit with automatic reset, a manually operated pressure regulator having an outlet for transmitting fluid pressure of a selected magnitude, an automaticmanual transfer fluid pressure applying means, a balancing unit ofa high gain pneumatic differential amplifier type, said balancing unit having a pair of input ports and an output port, a first fluid pressure operated automatic-manual transfer switch positioned in a first conduit that interconnects each of said input ports of said pneumatic balancing unit, a second fluid pressure transmitting conduit extending between one of said input ports of said balancing unit and an output port of said control unit, a third conduit extending between said output port of said balancing unit and a reset chamber associated with a feedback side of said pneumatic control unit, a second fluid pressure operated automatic-manual transfer switch positioned in said third conduit between the output port of said balancing unit and said reset chamber, a rate unit having an input conduit connected to said second conduit and an output fourth conduit connected to a feedback chamber of said control unit,
  • a pneumatic proportional integrating control apparatus as specified in claim 1 and wherein said balancing unit includes a beam, a pressure receiving means for receiving a pair of input pressure signals and which is operative to convert a difference in pressure between s i n yt i nt0 s nespend n d placement of said beam, a nozzle-flapper means connected to a pressure supply means for converting the displacement of said beam into a corresponding output pressure signal which is variable over a range from above atmospheric pressure to below atmospheric pressure, said balancing unit including an orfice plate as a restriction in a passage between the nozzle and the pressure supply means, and

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Feedback Control In General (AREA)
US26800272 1971-07-13 1972-06-30 Pneumatic control apparatus Expired - Lifetime US3823725A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP5236171A JPS5419956B1 (enrdf_load_stackoverflow) 1971-07-13 1971-07-13
US26800272 US3823725A (en) 1971-07-13 1972-06-30 Pneumatic control apparatus
IT5140772A IT960994B (it) 1971-07-13 1972-07-07 Perfezionamento nei servosistemi pneumatici di tipo proporzionale ad integrazione
DE2233761A DE2233761A1 (de) 1971-07-13 1972-07-08 Pneumatischer pid-regler
GB3276472A GB1393260A (en) 1971-07-13 1972-07-13 Pneumatic control apparatus
FR7225421A FR2145662B1 (enrdf_load_stackoverflow) 1971-07-13 1972-07-13

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5236171A JPS5419956B1 (enrdf_load_stackoverflow) 1971-07-13 1971-07-13
US26800272 US3823725A (en) 1971-07-13 1972-06-30 Pneumatic control apparatus

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US3823725A true US3823725A (en) 1974-07-16

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US26800272 Expired - Lifetime US3823725A (en) 1971-07-13 1972-06-30 Pneumatic control apparatus

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US (1) US3823725A (enrdf_load_stackoverflow)
JP (1) JPS5419956B1 (enrdf_load_stackoverflow)
DE (1) DE2233761A1 (enrdf_load_stackoverflow)
FR (1) FR2145662B1 (enrdf_load_stackoverflow)
GB (1) GB1393260A (enrdf_load_stackoverflow)
IT (1) IT960994B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE34202E (en) * 1989-11-02 1993-03-30 Johnson Service Company Dual mode pneumatic control system
US20060169137A1 (en) * 2005-02-01 2006-08-03 Roks Martinus F M Pneumatically operated automatic shutoff circuit for controlling the generation of gas
US20110070101A1 (en) * 2008-04-11 2011-03-24 Knorr-Bremse Systeme Fuer Nutzfahrzeuge Gmbh Valve Plate for a Compressor, and Method for Cooling Compressed Air in a Valve Plate of a Compressor
CN106365257A (zh) * 2016-11-14 2017-02-01 河南锦源环保科技有限公司 一种无机膜全气动自动控制系统
CN106379963A (zh) * 2016-11-14 2017-02-08 河南锦源环保科技有限公司 一种管式膜气液谐振过滤装置及其使用方法
US20170284604A1 (en) * 2014-07-18 2017-10-05 Instrument Solutions Inc. System, method, and apparatus for regulating the flow of gas

Families Citing this family (2)

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Publication number Priority date Publication date Assignee Title
DE3035990A1 (de) * 1980-09-24 1982-04-29 Eckardt Ag, 7000 Stuttgart Pneumatische nachfuehreinheit
CN111911809B (zh) * 2020-08-28 2025-06-27 银川英奥特自控股份有限公司 高精度气动比例积分调节器

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Publication number Priority date Publication date Assignee Title
US3680580A (en) * 1970-09-01 1972-08-01 Foxboro Co Bumpless-transfer control system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3680580A (en) * 1970-09-01 1972-08-01 Foxboro Co Bumpless-transfer control system

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE34202E (en) * 1989-11-02 1993-03-30 Johnson Service Company Dual mode pneumatic control system
US20060169137A1 (en) * 2005-02-01 2006-08-03 Roks Martinus F M Pneumatically operated automatic shutoff circuit for controlling the generation of gas
US7387659B2 (en) * 2005-02-01 2008-06-17 Parker Hannifin Corporation Pneumatically operated automatic shutoff circuit for controlling the generation of gas
US20110070101A1 (en) * 2008-04-11 2011-03-24 Knorr-Bremse Systeme Fuer Nutzfahrzeuge Gmbh Valve Plate for a Compressor, and Method for Cooling Compressed Air in a Valve Plate of a Compressor
US8337177B2 (en) 2008-04-11 2012-12-25 Knorr-Bremse Systeme Fuer Nutzfahrzeuge Gmbh Valve plate for a compressor, and method for cooling compressed air in a valve plate of a compressor
US20170284604A1 (en) * 2014-07-18 2017-10-05 Instrument Solutions Inc. System, method, and apparatus for regulating the flow of gas
US10508774B2 (en) * 2014-07-18 2019-12-17 Dean Leonidas Koulogianes System, method, and apparatus for regulating the flow of gas
US11204135B2 (en) 2014-07-18 2021-12-21 Devtech Sales, Inc. System, method, and apparatus for regulating the flow of gas
CN106365257A (zh) * 2016-11-14 2017-02-01 河南锦源环保科技有限公司 一种无机膜全气动自动控制系统
CN106379963A (zh) * 2016-11-14 2017-02-08 河南锦源环保科技有限公司 一种管式膜气液谐振过滤装置及其使用方法

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IT960994B (it) 1973-11-30
DE2233761A1 (de) 1973-02-15
FR2145662B1 (enrdf_load_stackoverflow) 1977-01-14
GB1393260A (en) 1975-05-07
JPS5419956B1 (enrdf_load_stackoverflow) 1979-07-19
FR2145662A1 (enrdf_load_stackoverflow) 1973-02-23

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