US3625239A - Transfer element for a measuring or control device - Google Patents

Transfer element for a measuring or control device Download PDF

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Publication number
US3625239A
US3625239A US782633A US3625239DA US3625239A US 3625239 A US3625239 A US 3625239A US 782633 A US782633 A US 782633A US 3625239D A US3625239D A US 3625239DA US 3625239 A US3625239 A US 3625239A
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US
United States
Prior art keywords
pressure
conduit
transfer element
throttle valve
nozzle
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
US782633A
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English (en)
Inventor
Horst Bader
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JC Eckardt AG
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JC Eckardt AG
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Publication date
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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
    • F15C1/00—Circuit elements having no moving parts
    • 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
    • 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]
    • Y10T137/2164—Plural power inputs to single device
    • Y10T137/2169—Intersecting at interaction region [e.g., comparator]
    • Y10T137/2174—Co-lineal, oppositely-directed power inputs [e.g., impact modulator]
    • 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]
    • Y10T137/218—Means to regulate or vary operation of device
    • Y10T137/2202—By movable element

Definitions

  • the present invention relates to a new use of a jet apparatus of a general type known as such and to improvements in such an apparatus to permit it to be used as a transferring and control element in or for a measuring or control device which is operated by the flow of a pressure medium by bringing at least two pressure values into operative association with each other which are applied to the jet apparatus to be used thereon selectively as the main jet pressure, as the back pressure, or as the suction pressure of this apparatus.
  • the invention relates further to a transfer element for a measuring or control device which is operated by a pressure medium and comprises a jet apparatus and a throttle valve or a restriction in the main pressure line, in the back-pressure line, and in the suction-pressure line of this apparatus.
  • jet apparatus as used in connection with the present invention includes all apparatus which operate by the well-known induction principle or Bernoulli's law, such as suction jet pumps which are operated by a fluid, Venturi tubes, ejectors which are also called jet compressors and are operated by air, and steam injectors.
  • the application of the fluid-pressure-operated transfer element in accordance with the invention has the advantage of resulting in a space-saving mechanism for dealing with the pressure values in measuring and control devices. This is due to the fact that a series of mechanical components of the known devices may be omitted. This will become apparent from the following description.
  • the known types of measuring and control devices such as pneumatic controllers and transmitters are provided with mechanical comparing elements in the form of diaphragm capsules (resilient tubes or bellows) or the like which have the purpose of first transforming the pressure values into forces and movements.
  • a comparing element which may, for example, consist of a pivotable lever or a rocker, a ring, or a wobble plate.
  • Such a comparing element is moved in accordance with the pressure values.
  • a part of this comparing element serves as a flapper in a flapper-nozzle system which converts the movements of this comparing element back into a pressure value which usually is then conducted to a pneumatic amplifier (relais).
  • the flappernozzle system comprises an outlet nozzle to which the pressure medium is supplied from a constant source thereof via a fixed restriction and from this nozzle the pressure medium flows against the flapper and then to the atmosphere.
  • Each of these known principles of transforming pressure values may generally be regarded as a mechanical comparing element for controlling a flapper-nozzle system.
  • Such a mechanical comparing element necessarily has to be of a construction which requires numerous components as well as considerable space, and because ofits spring-mass system it forms an oscillatory system with one or several degrees of freedom which may lead to undesirable oscillations.
  • the present invention has the object to overcome these disadvantages and it consists primarily in the discovery that the jet apparatus which are known in fluid mechanics for other purposes are especially suitable to be employed as transfer elements for fluid-actuated measuring and control devices if the corresponding pressure values are supplied to the jet apparatus as a main jet pressure, as a back pressure, or as a suction pressure. depending upon the particular purpose of the device.
  • the present invention has among others the advantage that mechanical comparing elements and flapper-noz2le systems are no longer required and that all components may be eliminated which were previously required for first converting the pressure values into forces and movements and for then reconverting the latter into a pressure value. On the conelement according to flow of the pressure medium which depends upon the pressure values of the latter.
  • the transfer element which has only two components namely the jet apparatus and the throttle valve or valves or restrictions to which, if required a third component may be added in the form of an amplifier. These components are connected to each other by chan els or pipes in the particular manner as required.
  • the transfer element according to the invention may be further applied with advantage, for example, in connection with computing apparatus which are operated by a pressure medium.
  • the known computers of this type for example, root-extracting mechanisms, produce the mathematically necessary dependence of the pressure values upon each other by mechanical means such as cam plates, l-cosa)-gears, toggle-joint gears, and the like.
  • These mechanical means may be replaced by the transfer element according to the invention if the transfer element is adjusted so as to serve as a function generator and is inserted, for example, into the feedback path of an amplifier. For this adjustment, the'transfer element is provided with further adjustable throttle valves or restrictions.
  • Such transfer elements may also be inserted into the feedback path of an apparatus which is equipped with a mechanical comparing element so that a combination of the transfer element according to the invention with mechanical comparing systems of a known type will thus be attained. If such a combination is employed, the mechanical root-extracting mechanisms as mentioned above may be omitted.
  • the jet apparatus As a transfer element to the ranges of the pressure values, it is provided with the throttling valves as previously mentioned which may be adjustable and may be selectively located in the mainjet line, in the backpressure line, and in the suction-pressure line of the apparatus.
  • FIG. 1 shows a diagrammatic longitudinal section of a transfer element according to the present invention which comprises ajet apparatus and throttle valves;
  • FIG. 2 shows a symbolic illustration of the transfer element according to FIG. 1;
  • FIGS. 3 to 7 respectively show different families of characteristics which may be attained by means of the transfer element according to the invention.
  • FIG. 8 shows a circuit diagram of the transfer element in its arrangement as a function generator in the feedback path ofa pneumatic-mechanical measuring and control device which may be employed, for example, for root extracting; while FIG. 9 shows a circuit diagram of several transfer elements according to the invention in a fluid-actuated controller.
  • FIGS. l and 2 of the drawings illustrate a jet apparatus of a type known as such which is enclosed in a housing I as indicated diagrammatically and consists of a nozzle 2 at the end of the main pressure or jet line 3, a suction chamber 4 at the end of the suction line 5, and a back-pressure chamber 6 which is located behind the narrowest cross-sectional area of flow at the end of the back-pressure line 7.
  • the apparatus is further provided with another pressure line 8 which terminates into the back-pressure line 7.
  • the main pressure line 3 is controlled by an adjustable throttle valve w the suction line by an adjustable throttle valve w and the back-pressure line 7 by an adjustable throttle valve w which connects the back-pressure chamber 6 with the atmospheric pressure p,,.
  • the additional pressure line 8 is likewise controlled by an ad justable throttle valve W
  • the apparatus is pro vided with connecting lines 9, l0, and I] which connect the main pressure line 3 with the back-pressure line 7 or the suction line 5 with the back-pressure line 7, respectively.
  • the connecting lines 9, l0, and 11 are likewise equipped with adjustable throttle valves W W and w In the jet apparatus the main pressure p the suction pressure p and the back pressurep occur. These three pressures together with the geometric dimensions of the jet apparatus determine the amounts of the pressure medium with which this apparatus is operated and they are mutually dependent upon each other.
  • the apparatus which is used as a transfer element is connected to the pressures x, y, z, and p, which form the input and output valves of the transfer element.
  • the inner pressures p 2 and p are brought by throttle valves first into a further relationship to each other and second into a dependence upon the outer pressures x, y, z, and p to which the transfer element is connected.
  • the outer throttle valves w W). w and W then serve primarily for adapting the transfer element to the preset pressure ranges and to the operating point of an adjacent loop element of a control circuit, for example, an amplifier, whereas the inner throttle valves W W and W are primarily adapted to produce different kinds of families of characteristics of the transfer element.
  • FIG. 3 illustrates the family of characteristics of a jet apparatus of a conventional type which is operated with compressed air.
  • the pressure P in the suction chamber of the apparatus is indicated as being dependent upon the given value y, while the back pressure p p etc. which is adjusted by the throttle valve W serves as parameter.
  • This family of characteristics also corresponds to that of the transfer element according to the invention if the throttles in the connecting lines 9, I0, and II are closed. It indicates that, with the exception of the marginal curves l2 and 13, all other characteristics are nonlinear curves which are generally unsuitable for associating a certain suction pressure p with the value y.
  • the family of characteristics of the suction pressure 1 is indicated in relation to the value y.
  • the throttle valves w,, w,,, w,, and w are employed for the parameters adjustment but also the throttle valve W Depending upon the position of the throttle valve W the characteristics now result in a series of straight lines which, contrary to those in FIG. 4, are downwardly inclined and permit the new transfer element to be used, for example, like the arrangement according to FIG. 4 as a negative feedback in a feedback path ofa measuring and control device.
  • FIG. 6 shows the family of characteristics which results when the throttle valves w w,-, w (or W and w are effective, while the throttle valves w and w remain closed.
  • FIG. 7 shows the family of characteristics p in relation to the value y.
  • This set of curves may be regarded as the reverse to the parabolas of FIG. 6. It results when aside from the outer throttle valves w W W and possibly w also the throttle valve w is employed for the parameter adjustment, while the throttle valves w and W31 remain closed.
  • This arrangement in which the formation of the different curves likewise depends upon the position of the throttle valve WM; may be employed, for example, when a square association of the pressure values is required, for example, in computers or the like.
  • the transfer element 1 is located within the feedback path of an amplifier 15 with a negative feedback.
  • the transfer element 1 is assumed to be adjusted as described with reference to the family of characteristics according to FIG. 6 and the throttle valve w is therefore also employed as a parameter.
  • This family of characteristics contains a square association between p and y. If by means of a proportional element P which may consist, root-extracting example, ofa lever, a value .t which is proportional to the suction pressure 1,,- acts in opposition to the input value .t',. of the rootextracting apparatus, the desired root-extracting effect will be attained.
  • the comparing device 14 which forms the difference between the values x and x, and conducts to the amplifier a value which is proportional to this difference may be designed as a mechanical comparing device with the result that a combination of the transfer element 1 with a mechanical comparing device is formed.
  • the usual mechanical rootextracting gear is replaced by the transfer element I in which the parameter may be adjusted accordingly.
  • Such a pressure-actuated comparing device may be formed, for example, of a transfer element according to FIGS. I and 2.
  • the values .r and y are then used as independent variables, that is, as input values, and p as output value.
  • This use of the transfer element constitutes a combination of its use in accordance with the previous description of FIGS. 4 and 5.
  • p increases in proportion to the input signal x and decreases in proportion to the second input signal y. This results in the formula:
  • variable x is not applied directly on the throttle valve WX of the transfer element, but via a further adjustable throttle valve. This case is illustrated in FIG. 9.
  • the input value x acts through the adjustable throttle valve w upon the input pressure signal p, of the amplifier 16.
  • the input value x acts through the transfer element la upon the pressure p,,-. This occurs in this case because x determines the main jet pressure of the transfer element Ia and thus the volume of pressure medium which is drawn off the input pressure chamber of the amplifier 16 in which the pressure p prevails.
  • the same arrangement of a transfer element lb with an additional throttle valve is now employed according to FIG. 9 to form a feedback path for the amplifier 16.
  • the output pressure y of the amplifier then acts upon the transfer element lb in such a manner that the pressure y determines the main jet pressure p
  • a further pressure value x is connected through the throttle valve w' to the pressure camber p This throttle valve and the constant pressure signal x, serve for the purpose of adapting the range of values of the pressure p, to the operating point of the amplifier or vice versa.
  • FIG. 9 illustrates a proportional control device which is actuated by a pressure medium.
  • This apparatus is composed of two pressure-actuated comparing devices and the amplifier 16.
  • the first comparing device is formed by the transfer element la and the throttle valve w to which the input pressures .r,,, and x are connected. This comparing device serves for determining the deviation of the actual value from the nominal value.
  • the second comparing device is provided in the feedback path of the amplifier 16.
  • a fluid-actuated comparing instrument which is designed in accordance with FIG. 9 may be formed ofa transfer element and one additional throttle valve. It may, however, also be formed of two transfer elements according to FIGS. 1 and 2. Other combinations or the replacement of further throttle valves may also be attained by employing transfer elements according to the invention.
  • the present invention concerns a transfer element for the association of pressure values which may be employed for a multitude of different purposes and may be easily manufactured.
  • a transfer element for correlating pressures in a measuring or control device which is actuated by the flow of a pressure medium by operatively associating at least two pressure values with each other and comprises ejector means having a nozzle and a venturi arranged coaxially with the nozzle, and means for supplying said pressure values selectively to and employing them in said ejector means as a main jet pressure, as a back pressure, or as a suction pressure.
  • a transfer element for a measuring or control device actuated by a fluid pressure medium comprising ejector means having a nozzle and a venturi arranged coaxially with the nozzle, conduits for supplying a main jet pressure, a back pressure, and a suction pressure to said ejector means, and at least one throttling restriction or throttle valve in one of said conduits.
  • a transfer element as defined in claim 9, further comprising a connecting conduit between said main-pressure conduit and said suction-pressure conduit with a throttling restriction or throttle valve disposed therein, and a connecting conduit between said back-pressure conduit and said suctionpressure conduit with a throttling restriction or throttle valve disposed therein.
  • a transfer element for the correlation of pressures for pressure-medium-operated measuring and controlling devices comprising ejector means having a nozzle and a venturi arranged coaxially with the nozzle, and at least one throttle restriction disposed in a power stream conduit, and/or in a back-pressure conduit. and/or in a suction-pressure conduit of said ejector means.

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Mechanical Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)
  • Control Of Positive-Displacement Air Blowers (AREA)
  • Control Of Fluid Pressure (AREA)
  • Jet Pumps And Other Pumps (AREA)
US782633A 1967-12-22 1968-12-10 Transfer element for a measuring or control device Expired - Lifetime US3625239A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1807767A CH463833A (de) 1967-12-22 1967-12-22 Ubertragungsglied für druckmittelbetriebene Mess- und Regeleinrichtungen

Publications (1)

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US3625239A true US3625239A (en) 1971-12-07

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US782633A Expired - Lifetime US3625239A (en) 1967-12-22 1968-12-10 Transfer element for a measuring or control device

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US (1) US3625239A (enrdf_load_stackoverflow)
CH (1) CH463833A (enrdf_load_stackoverflow)
DE (1) DE1807712B1 (enrdf_load_stackoverflow)
FR (1) FR1588045A (enrdf_load_stackoverflow)
GB (1) GB1255023A (enrdf_load_stackoverflow)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3128040A (en) * 1962-10-29 1964-04-07 Ibm Fluid logic device
US3159168A (en) * 1962-02-16 1964-12-01 Sperry Rand Corp Pneumatic clock
US3250469A (en) * 1963-08-05 1966-05-10 Bowles Eng Corp Pure fluid function generating system
US3388713A (en) * 1965-01-25 1968-06-18 Johnson Service Co Pure fluid summing impact modulator and universal amplifiers constructed therewith
US3444878A (en) * 1966-04-04 1969-05-20 Bendix Corp Fluid control device
US3459206A (en) * 1965-10-22 1969-08-05 Bowles Eng Corp Statistical device
US3467122A (en) * 1965-09-27 1969-09-16 Bowles Eng Corp Liquid level sensor
US3473545A (en) * 1967-03-20 1969-10-21 Bendix Corp Fluid pressure regulator

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3159168A (en) * 1962-02-16 1964-12-01 Sperry Rand Corp Pneumatic clock
US3128040A (en) * 1962-10-29 1964-04-07 Ibm Fluid logic device
US3250469A (en) * 1963-08-05 1966-05-10 Bowles Eng Corp Pure fluid function generating system
US3388713A (en) * 1965-01-25 1968-06-18 Johnson Service Co Pure fluid summing impact modulator and universal amplifiers constructed therewith
US3467122A (en) * 1965-09-27 1969-09-16 Bowles Eng Corp Liquid level sensor
US3459206A (en) * 1965-10-22 1969-08-05 Bowles Eng Corp Statistical device
US3444878A (en) * 1966-04-04 1969-05-20 Bendix Corp Fluid control device
US3473545A (en) * 1967-03-20 1969-10-21 Bendix Corp Fluid pressure regulator

Also Published As

Publication number Publication date
GB1255023A (en) 1971-11-24
DE1807712B1 (de) 1970-11-12
FR1588045A (enrdf_load_stackoverflow) 1970-04-03
CH463833A (de) 1968-10-15

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