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
  • F04B49/06—Control using electricity
  • F04B49/065—Control using electricity and making use of computers
• • 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
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/20—Control of fluid pressure characterised by the use of electric means
  • G05D16/2006—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means
  • G05D16/2066—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means using controlling means acting on the pressure source
• • 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
  • F04B2205/00—Fluid parameters
  • F04B2205/06—Pressure in a (hydraulic) circuit
  • F04B2205/061—Pressure in a (hydraulic) circuit after a throttle
• • 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
  • F04B2205/00—Fluid parameters
  • F04B2205/17—Opening width of a throttling device
  • F04B2205/172—Opening width of a throttling device after the pump outlet

Definitions

• the present invention relates to a device for controlling a water pump. Description of the Prior Art
• a first system makes use of a switch operated by pressure pulses which activates and deactivates the electric pump between minimum and maximum pressure values detected in the water main; the switch is associated to a liquid accumulator with an air-loaded flexible diaphragm with the function of extending the intervals of time between the pump cutting in and cutting out.
• the drawbacks associated with this system are well known and can be summarized mainly as: high installation and maintenance costs, limited scope of usefulness, and the risk of the water becoming polluted as the result of bacteria " proliferating on the diaphragm.
• a device disclosed in Italian patent application n° MI91A 002777 is substantially similar, the only significant differences being that the diaphragm is counterbalanced by a spring and that the flow control and check valve has no return spring and therefore can be installed only in the vertical position. Finally, in a device of the same type made by the Italian company RITEC S.r.l., the flow control valve is replaced by a pulse turbine, again in conjunction with a Hall effect transducer.
• a further drawback affecting all the above mentioned systems is their inability to recognize a drop in pressure caused not by effective user demand, but rather by small leaks which cause the pump to cut in continually and replenish the loss, wasting both water and energy.
• a first object of the present invention is to provide a control device for a water-pressurizing electric pump unaffected by the drawbacks mentioned above, and in particular a device that makes no use of a diaphragm type pressure sensing element.
• a further object of the present invention is to provide a device of the aforementioned type such as will monitor pressure continuously, identifying and responding automatically to a variety of situations that may arise during the operation of the system served by the pump, including structural changes to the system itself.
• control device for an electric pump which comprises a body hydraulically connectable to the delivery side of the pump and to an outlet section from which water flows to the system which has to be fed.
• the body accommodates a flow sensing and flow check means .
• Pressure is sensed by a gauge element associated with the outlet section and capable of generating digital information that will be a function of the pressure sensed within the section.
• the output signals from the flow and pressure sensing elements are managed by a microprocessor that pilots the activation and deactivation of the pump in response to these signals and on the basis of previously programmed instructions.
• -figure 1 is a median longitudinal section of the device according to the invention, viewed in an operating position assumed when there is no flow present;
• -figure 2 is a longitudinal section identical to that of figure 1, illustrating the device in an operating position assumed when flow is present;
• -figure 3 illustrates a pressure sensing means associated with the outlet section of the device
• the device comprises a body 1 having a tubular portion la of varying section and an open housing lb extending from one side of the tubular portion.
• the tubular portion la presents an internally threaded portion of larger section lc, coinciding with the water inlet, and an externally threaded portion of smaller section Id that coincides with the water outlet.
• a cylindrical sleeve 2 screwed into and coaxial with the endmost part of the inlet section lc of body 1 in such a way substantially as to form an extension of said section; an O-ring 3 is fitted to the outer surface of sleeve 2 ensuring a fluid tight coupling.
• the larger section lc of body 1 houses a check valve 5 consisting in a stem 5a axially free accomodated within seats 4, and a circular plate 5b coaxial with stem 5a, of which the diameter is marginally greater than the bore of sleeve 2.
• Plate 5b is breasted tightly with sleeve 2, so as to prevent water from flowing through the bore, by a conical coil spring 6 mounted around stem 5a between plate 5b and seat 4 in section la.
• the side of plate 5b contacting sleeve 2 is provided with a seal 7.
• a permanent magnet 8 is mounted to the end of a radial arm 5c extending upwards from stem 5a.
• Housing lb accomodates a pressure gauge 11 of substantially conventional embodiment, consisting in a Bourdon tube, which is connected externally to section Id by way of a threaded cylindrical metal element 11a, sealingly engaging, by way of an O-ring 10, in a threaded hole 9 formed through the wall of section Id.
• Element 11a affords a pressure sensing duct 12 interconnecting the bore of section Id with the bore of Bourdon tube lib, which extends from cylindrical element 11a.
• a precision mechanism lie is pivotally associated with the end of the Bourdon tube, and in its turn engages in meshing contact by way of a toothed sector lid with the lateral surface of a cylindrical pin 13, pivotally supported by an inside wall of housing lb, of which the free end carries a rotary encoder 14.
• an electronic circuit board denoted 15 carrying a number of components of which the specific functions will be described hereinafter: an optical sensor 16 positioned in such a way as to read encoder 14; a microprocessor 17; a reset button 18; three light emitting diodes 19; and a Hall effect transducer 20 positioned in such a manner as to ensure its exact alignment with magnet 8 when check valve 5 is closed. Finally, the necessary wires are routed through an access hole 21 afforded by one wall of housing lb.
• Housing lb is fitted with a cover 22 and an interposed seal 23, secured by means of screws 24.
• Projecting from the inside face of cover 22 are a set of light guides 25, positioned in alignment with LEDs 19 and capped by lens elements 26, by which the glow from LEDs is conveyed to the surface, and also a pin 27, positioned in alignment with reset button 18, providing the means by which to depress the button, exploiting the limited flexibility of cover 22.
• the operation of the control device according to the invention is the following.
• the pump is activated by depressing reset button 18, whereupon water coming from the pump enters body 1 by way of sleeve 2 connected to the inlet section, displacing check valve 5 as shown in figure 2.
• the displacement of the valve causes magnet 8 to move away from the Hall effect transducer 20, which trasmits a signal to the electric motor, to keep the pump into operation.
• Downstream of check valve 5 a part of the pressurized flow of water passes into sensing duct 12 from section Id of body 1 then up through cylindrical element 11a into Bourdon tube lib.
• the tube undergoes a deformation, causing a shift of mechanism lie and sector lid that causes pin 13 to rotate about its axis, and with it encoder 14.
• the movement of encoder 14 creates digital combinations that are decoded by optical sensor 16, the sensor in turn being connected to microprocessor 17 which is able as a result to receive signals corresponding to the pressure sensed through the gauge.
• microprocessor 17 which is able as a result to receive signals corresponding to the pressure sensed through the gauge.
• the analysis of these signals allows to pilot the operation of the pump on the basis of a previously installed program.
• the water leaves the device through section Id and is directed into the circuit served by the pump.
• the delay ensures that the pump is given time to restore full pressure in the system before shutting off. At this point the encoder stays put on the combination most recently formulated, representing maximum pressure with the pump operating and the check valve closed. If a tap is turned on and pressure in the system then falls below a minimum set point, this will be sensed by way of the encoder and the pump restarted so that pressure is restored.
• Microprocessor 17 is programmable, as already said, in such a way as will enable the device to perform a range of self-regulating and self-test functions: identifying a shutdown caused by the pump running dry and thereafter entering a control sequence to reset and restart the pump; self regulation of the minimum pressure set point at which the pump cuts in; detection of leaks from the system.
• identifying a shutdown caused by the pump running dry and thereafter entering a control sequence to reset and restart the pump self regulation of the minimum pressure set point at which the pump cuts in; detection of leaks from the system.
• the device will lock up and generate signals serving in the example of figure 4 to light up the indicator LEDs 19; other alternative and/or parallel acoustic warning systems might be adopted to equally good effect . Once the water returns, normal operating conditions can be reinstated by pressing the reset button 18.
• the microprocessor activates the pump and memorizes the pressure registering in the column above the device as the water reaches the tap located highest up in the system, which will have been opened beforehand.
• the minimum pressure set point at which the pump cuts in will then be established at a value exceeding the memorized value by a given programmable amount .
• the microprocessor is also capable of detecting leaks in the system. As shown in block C of the flow diagram, the microprocessor keeps a statistical record of the starts made by the pump, and on detecting any recurring pattern over a predetermined lapse of time, even with intervals of high consumption suggesting water demands from the users, will proceed to indicate the possible existence of a leak by generating an alarm signal to activate a visual indicator (LED 19) or a sounder.
• a visual indicator LED 19
• the device according to the invention represents a significant step forward in the state of the art, resolving as it does a whole series of problems in devices as used hitherto for the same purpose, and affording additional features of great usefulness .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Control Of Positive-Displacement Pumps (AREA)
• Fluid-Pressure Circuits (AREA)
• Control Of Transmission Device (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=11394075

Family Applications (1)

Country Status (3)

Families Citing this family (13)

Family Cites Families (7)

• 1997
  • 1997-02-13 IT IT97PI000009A patent/IT1295577B1/it active IP Right Grant
• 1998
  • 1998-02-13 EP EP98905610A patent/EP0901654A1/en not_active Withdrawn
  • 1998-02-13 WO PCT/IT1998/000024 patent/WO1998036339A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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