EP1077332A2 - Fluiddruckregler für Pumpen - Google Patents

Fluiddruckregler für Pumpen Download PDF

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Publication number
EP1077332A2
EP1077332A2 EP00117204A EP00117204A EP1077332A2 EP 1077332 A2 EP1077332 A2 EP 1077332A2 EP 00117204 A EP00117204 A EP 00117204A EP 00117204 A EP00117204 A EP 00117204A EP 1077332 A2 EP1077332 A2 EP 1077332A2
Authority
EP
European Patent Office
Prior art keywords
controlling
electronic device
pump
capacitor
pumps
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.)
Withdrawn
Application number
EP00117204A
Other languages
English (en)
French (fr)
Other versions
EP1077332A3 (de
Inventor
Fausto Costola
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.)
WORLDWIDE ENGINEERING LLC
Original Assignee
Bross Engineering SA
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 Bross Engineering SA filed Critical Bross Engineering SA
Publication of EP1077332A2 publication Critical patent/EP1077332A2/de
Publication of EP1077332A3 publication Critical patent/EP1077332A3/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/02—Stopping, starting, unloading or idling control
    • F04B49/022—Stopping, starting, unloading or idling control by means of pressure

Definitions

  • the present invention relates to a device for controlling the operation of pumps in hydraulic circuits by detecting the pressure of the circuit and consequently issuing the command to activate or stop the pump.
  • pressure-controlled switches which are constituted by a membrane which is loaded by a contrasting spring whose effect is adjustable and actuates switches or microswitches.
  • Such devices can be set in the laboratory and according to a single intervention point, i.e., the device activates and deactivates the pump only when the pressure in the circuit is respectively lower or higher than a given preset value, and is also subject to fixed hysteresis effects.
  • twin pressure-controlled switches which are constituted by membranes or bellows and contrast springs which are composed of two individually settable microswitches.
  • Another type of device is constituted by an electronic pressure sensor which is constituted by a pressure transducer, usually a piezoresistive silicon diaphragm, which is accommodated within a steel body.
  • An elastic membrane is then coupled to the silicon diaphragm by means of an insulating fluid.
  • the sensor normally provides a full-scale voltage of 100 mV.
  • This voltage is sent to a microcontroller, which is associated with an analog/digital converter which allows to display the value of the detected pressure, expressed in bars, and drives the pump according to a preset program.
  • These sensors are normally provided with threaded couplings to be coupled to the measurement pipe; accordingly, there is the need for a thread and a sealing gasket.
  • the output of the sensor must necessarily be coupled to the electronic circuit by means of cables and a connector; this operation is very delicate, since the sensor and the electronic circuit are located proximate to the pump, which generates electrical-field and magnetic-field noise, and all this also has a negative impact on constructive simplicity.
  • the aim of the present invention is to provide a device for controlling the operation of pumps in which the drawbacks noted above in conventional devices of this type are eliminated.
  • a consequent primary object is to provide a device for controlling the operation of pumps which is constructively very simple.
  • An important object is to provide a device which provides a frequency output and can therefore be easily controlled by a microcontroller without the need for an analog/digital conversion card and with an output signal which is immune to noise and interference.
  • Another object is to eliminate the presence of cables and connectors.
  • Another object is to provide a device whose operation requires a very small amount of current.
  • Another object is to provide a highly compact device.
  • Another object is to provide a device which differs from conventional commercially available ones owing to its very low manufacturing and purchase cost.
  • a device for controlling the operation of pumps characterized in that it comprises an oscillating circuit in which the capacitor is a capacitive transducer which cooperates with at least one mechanical actuator for actuating at least one of the plates of the capacitor and means for interfacing with the pump, said actuator being subjected to the pressure of the fluid.
  • a device for controlling the operation of pumps comprises a sensor which is constituted by a piston 10 which cooperates with a sealing membrane 11 which is subjected to the pressure to be detected.
  • the piston 10 has a coaxial end protrusion 12 which passes through a hole 13 formed at the center of a support 14 for printed circuits, made of fiberglass-reinforced plastics.
  • a rectangular copper surface 15 is provided on said support 14, on the surface that lies opposite the surface 24 that faces the actuator, and is connected to the surface 24 of the support 14 by metallization of the hole 13 and the path 16.
  • a film of insulating paint is screen-printed over the rectangular surface 15.
  • the rectangular surface 15 constitutes the fixed plate of the capacitor, which is generally designated by the reference numeral 17.
  • the movable plate is instead designated by the reference numeral 18 and is constituted by a rectangle of spring steel plate.
  • the movable plate 18 is fixed to the support 14 on one side 22 by means of the fixed element 19, which in addition to allowing the flexing of the plate 18 is capable of transferring electrical contact to the opposite surface 24 of the support 14, while the opposite side 21 rests on a guide 20 which allows it to slide on the support 14 but not separate from it.
  • the capacitor 17 is part of an oscillating circuit 23, shown schematically in Figure 3, which is directly connected to a microcontroller designated by the same reference numeral.
  • the oscillating circuit and the microcontroller form an electronic circuit 23 which is placed on the surface 24 of the support 14.
  • the oscillating circuit 23, shown in Figure 3, is constituted by an operational amplifier 26 with a rail-to-rail (inverse feedback) output, which is connected in a classical configuration as an RC oscillator which provides in output a frequency square wave; in said oscillator, the resistors R are designated by the reference numeral 27 and the capacitor C is the variable-capacitance capacitor 17.
  • the electronic circuit 23 is connected to the two plates of the capacitor by means of the connections 16 and 27.
  • the device is seated directly in the hydraulic circuit with the sealing membrane 11 in contact with the fluid.
  • the membrane 11 forces a movement of the piston 10, which is contrasted by the elastic plate 18 of the capacitor 17.
  • the capacitance of the capacitor 17 varies in inverse proportion to the distance between the plates 15 and 18; this variation is detected in output by the oscillating circuit 23, since it provides in output a frequency square wave which is proportional to the value of the capacitance of the system.
  • the output of the oscillating circuit is further connected to a microcontroller which, according to a preset program and by cooperating with a driver of the pump, regulates the operation of the pump.
  • the water head measurement program of the device according to the invention provides the following:
  • the pressure values are:
  • a device has in fact been provided which is constructively very simple and very compact.
  • the system further provides a frequency output, and this entails considerable advantages.
  • the system also features a very low current consumption and an extremely low manufacturing cost.
  • the oscillator can be directly connected to a comparator, which refers to a preset intervention value, and to a driver of the pump.
  • the materials used may be any according to requirements.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
EP00117204A 1999-08-17 2000-08-10 Fluiddruckregler für Pumpen Withdrawn EP1077332A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1999PD000194 IT1307380B1 (it) 1999-08-17 1999-08-17 Dispositivo per il controllo del funzionamento di pompe
ITPD990194 1999-08-17

Publications (2)

Publication Number Publication Date
EP1077332A2 true EP1077332A2 (de) 2001-02-21
EP1077332A3 EP1077332A3 (de) 2002-04-10

Family

ID=11392717

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00117204A Withdrawn EP1077332A3 (de) 1999-08-17 2000-08-10 Fluiddruckregler für Pumpen

Country Status (2)

Country Link
EP (1) EP1077332A3 (de)
IT (1) IT1307380B1 (de)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1282302B (de) * 1964-03-11 1968-11-07 Micromatic Hone Corp Kapazitativer Messumformer
CH667736A5 (de) * 1984-10-15 1988-10-31 Huba Control Ag Auf druck ansprechender geber.
GB2259147A (en) * 1991-08-15 1993-03-03 Burreng Limited Pressure sensor
US5580221A (en) * 1994-10-05 1996-12-03 Franklin Electric Co., Inc. Motor drive circuit for pressure control of a pumping system
EP0706038B1 (de) * 1994-10-07 1999-01-13 Omron Corporation Kapazitiver Druckwandler mit zwei Kammern

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
ITPD990194A1 (it) 2001-02-17
IT1307380B1 (it) 2001-11-06
EP1077332A3 (de) 2002-04-10

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