Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
  • F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D7/00—Control of flow
  • G05D7/06—Control of flow characterised by the use of electric means
  • G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
  • G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
  • G05D7/0676—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on flow sources
• • 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
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
  • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

• the present invention relates generally to air blowing devices, and it relates more particularly to a new method for adjusting the air flow rate and to a device implementing the method.
• a device for example an air treatment device of the air conditioner type
• it is necessary in the known technique to calibrate the device according to its environment; more precisely, it is necessary to calibrate the device as a function of the pressure drops specific to the air distribution and return circuit in the room or rooms associated with the device and, where appropriate, as a function of the minimum air flows and maximums imposed by operators according to determined criteria, in particular occupancy criteria, situation, or even regulatory criteria or admissible noise level.
• the main purpose of this calibration is to determine, for each treatment device in its final environment, the law of evolution of the effective flow rate as a function of an electrical parameter of the power supply of the engine driving the fan.
• the present invention aims to overcome these drawbacks of the prior art and to propose an air treatment device which does not require any calibration during installation on site, this without its cost being significantly increased.
• the present invention is based on the idea that the electric motor driving the fan is in itself able to supply at any desired time information making it possible to deduce the effective pressure drop in the distribution and supply circuits. recovery associated with the device, and therefore to control the motor as a function of this pressure drop to obtain the desired flow rate.
• a method for adjusting the air flow rate at the outlet of an air blowing device comprising at least one fan driven by an electric motor and connected to a circuit of air, and means to vary a parameter of the motor supply voltage in.
• Said parameter consists of the effective value of the motor supply voltage.
• - Said information is a pulse signal whose frequency is proportional to the speed of rotation of the motor or the fan.
• the step of determining the law of evolution consists in determining, among a plurality of identifiers in association with which a plurality of respective criteria are memorized, the identifier whose criterion is satisfied by said parameter of the voltage of food and said information, said identifier determining said law of evolution.
• the invention relates to an ' air blowing device, characterized in that it comprises in combination: a fan driven by an electric motor, means for varying a parameter of the voltage electric motor supply in order to vary the speed of rotation thereof, means for measuring information representative of the speed of rotation of the motor, a memory containing a set of data o representative of a plurality of laws of evolution of the effective flow rate of the fan as a function of the value of said parameter of the supply voltage, and of the processing means for determining, from knowledge of said parameter of the supply voltage and of said information at least at a given instant, the appropriate evolution law, the means for varying said parameter of the supply voltage being controlled as a function of a set flow rate e and of said specific law.
• the electric motor is an asynchronous motor
• said means for varying said parameter comprise a conduction angle control unit
• said 5 * parameter is the effective value of the supply voltage of the motor.
• Said measuring means comprise a sensor chosen from the group comprising magnetoresistive sensors, Hall effect sensors and optical sensors.
• - Said memory is an interchangeable read only memory whose data correspond to a given motor-fan couple.
• the invention finally relates to a device for implementing the method as defined above, characterized in that it comprises: a fan driven by an electric motor, means for varying a parameter of the electric supply voltage of the motor with a view to varying the speed of rotation thereof, a sensor for generating the information representative of the speed of rotation of the motor, a memory containing said plurality of evolution laws, and processing means for effecting the step of determining and controlling said means for varying the parameter of the electrical voltage.
• FIG. 1 is a block diagram of part of an air treatment device according to the present invention
• FIGS. 2a to 2c show three diagrams corresponding to three theoretical environments of the device
• FIG. 3 shows a diagram illustrating the principle of flow adjustment used in accordance with the present invention.
• an air treatment device which comprises a fan or other blower 10 driven by an asynchronous electric motor 12.
• a duct 16 for distributing air and an air return duct 18.
• the basic principle of the present invention therefore consists in determining the slip of the motor by measuring the absolute rotation speed of the motor (or any other variable which is correlated). This measurement, compared with the nominal rotation speed, gives the engine slip at a given instant, itself representative of the pressure drop in the air circuit to which the fan is connected.
• the motor itself is used as the linear sensor element, the rotation speed measured for a given effective supply voltage will make it possible to deduce the pressure drop existing downstream of the fan, and therefore to determine a law of evolution of the effective flow rate as a function of the effective voltage applied to the motor.
• the device represented in FIG. 1 comprises a rotation sensor 14 whose output, for example delivering a determined number of electrical pulses per revolution accomplished by the motor, is applied to a regulating plate 20.
• This sensor 14 can be of any appropriate type. Thus one can use for example a magneto-resistive sensor, a Hall effect sensor, an optical sensor, etc.
• the plate 20 includes a computer 22 associated with a memory 24, and a speed variation module 26.
• the computer 22 receives on the one hand the output of the sensor 14, and on the other hand a set flow rate value supplied by the control unit of the air treatment device, not shown.
• the memory 24 contains, as will be seen in detail below, data representative of the evolution of the flow rate at the output of the fan as a function of the supply voltage of the motor, for various pressure drops in the air circuit.
• variable speed drive 26, controlled by the computer 22 is in the present example a conduction angle control unit, of conventional design, making it possible to vary the effective supply voltage of the motor as desired.
• Figures 2a, 2b and 2c show the variations in speed (solid lines) and flow rate (dashed lines) obtained as a function of variations in rms voltage, respectively with zero pressure drop (no load), average pressure drop and a high pressure drop (outlet almost blocked).
• this memorization may consist in individually identifying the different pressure drops PCi for which the measurements have been made, and in associating in the memory, in association with each of the different values PCi, a plurality of pairs of values (voltage effective, speed) corresponding to curves of the type of curves in solid lines illustrated in FIGS. 2a to 2c.
• a set of pairs of values (effective voltage, flow rate) corresponding to curves of the 'tvpe from those in dashed lines in FIGS. 2a to 2c.
• the computer 22 reads a value of rotational speed supplied by the sensor 14 and, simultaneously or practically simultaneously, reads the value of the effective voltage applied to the motor. From the data stored in memory 24, the computer 22 can then determine the level of pressure drop PCi (FIG. 3) currently caused by the air distribution and return circuit.
• the device of the present invention can be described as self-adaptive in that, without any intervention or adjustment, it adapts itself in real time to its environment, to ensure that the effective air flow at its output is always identical, except for tolerances, at the set flow rate.
• the device adapts in the same way to variations in pressure losses resulting from fouling or aging of the air circuit, without it being necessary to intervene.
• Another solution for memorizing the data in the memory may consist in determining and memorizing equations of curves which are as close as possible to the characteristic curves obtained experimentally.
• a first curve of the speed as a function of the effective voltage can be memorized, and a second curve of the flow rate as a function of the effective voltage.
• a limited number of curve equations can be used, these equations having variable parameters; and these are the parameters which are then stored opposite. respective identifiers PCi.
• the computer can perform the following operations:
• the final step consisting in adjusting the effective voltage applied to the motor to obtain the target flow rate can consist not in reading directly on the curve considered the value required for the effective voltage as a function of the target flow rate, but to read, on a different curve, the required rotation speed as a function of the set flow rate.
• the effective voltage is then varied, by simultaneously reading from the sensor 14 the effective speed of rotation, until the required speed of rotation is reached.
• the memories containing the data representative of the behavior of different given motor / fan couples can be physically constituted by read-only memories in integrated circuit, and it suffices during manufacture to install the integrated circuit whose data correspond to the motor / fan couple actually used.
• the invention advantageously applies in any installation in which an electric motor driving a fan or blower must be controlled so as to obtain an output of a given real flow rate, taking into account the pressure drops which may vary in the ducts. connected to the fan. It may in particular, but not limited to, be an air treatment module as it is the subject of French patent No. 2617952 in the name of the Applicant, or any heating, air conditioning, ventilation, drying installation, etc.
• the present invention makes use of a speed sensor allows, practically without additional cost, the computer to also perform various safety functions, and in particular to detect if the speed of rotation of the engine does not drop below this. of a given threshold, risking damaging its windings.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Control Of Positive-Displacement Air Blowers (AREA)
• Control Of Electric Motors In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9396387

Family Applications (1)

Country Status (5)

Cited By (4)

Families Citing this family (5)

Citations (1)

• 1990
  • 1990-05-07 FR FR9005714A patent/FR2661759B1/fr not_active Expired - Lifetime
• 1991
  • 1991-05-06 AU AU78905/91A patent/AU7890591A/en not_active Abandoned
  • 1991-05-06 WO PCT/FR1991/000374 patent/WO1991017491A1/fr unknown
  • 1991-05-07 TR TR91/0448A patent/TR25345A/tr unknown
  • 1991-05-07 PT PT97595A patent/PT97595A/pt not_active Application Discontinuation

Patent Citations (1)

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