Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N5/00—Systems for controlling combustion
  • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
  • F23N5/10—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples
  • F23N5/102—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples using electronic means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N1/00—Regulating fuel supply
  • F23N1/002—Regulating fuel supply using electronic means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
  • F23K2900/00—Special features of, or arrangements for fuel supplies
  • F23K2900/05001—Control or safety devices in gaseous or liquid fuel supply lines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N2235/00—Valves, nozzles or pumps
  • F23N2235/12—Fuel valves
  • F23N2235/14—Fuel valves electromagnetically operated
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N2235/00—Valves, nozzles or pumps
  • F23N2235/12—Fuel valves
  • F23N2235/18—Groups of two or more valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N2235/00—Valves, nozzles or pumps
  • F23N2235/12—Fuel valves
  • F23N2235/22—Fuel valves cooperating with magnets

Definitions

• the present invention relates to a device for controlling the supply of a combustible gas according to the precharacterizing clause of the principal claim (Claim 1).
• the invention relates particularly, but not exclusively, to the technical field of the control of the supply of combustible gas to burners provided on cooktops, gas ovens and similar equipment.
• thermomagnetic flame detection device of the thermocouple type for example.
• a principal object of the invention is to provide a gas supply control device which is structurally and functionally designed to give the equipment a wider range of functions, relating for example to the provision of a control for regulating the flow rate of gas supplied to the burner, but which is also integrated with a system for monitoring the flame and for shutting off the gas supply path for safety purposes, of the thermomagnetic type or any other type which is reliable and conforms to the technical standards governing the field.
• Another object is to provide a gas supply control device in which there is implemented, in addition to the flame regulation function, another function by which the flame on the cooktop is turned on and off in a delayed way, at the predetermined level of regulation, according to specified programming procedures.
• FIG. 1 is a functional block diagram of the device according to the invention.
• Figure 2 is a view in axial section of the gas supply control valve unit provided in the device according to the invention.
• Figure 3 is a front elevation of a further detail of the device according to the invention. Preferred embodiment of the invention
• the number 1 indicates the whole of a device including a valve unit 2 (delimited schematically by the frame drawn in broken lines) for controlling the supply of combustible gas to one or more burners 3 of a cooktop (not shown), made according to the present invention.
• a valve unit 2 delimited schematically by the frame drawn in broken lines for controlling the supply of combustible gas to one or more burners 3 of a cooktop (not shown), made according to the present invention.
• the gas is supplied through the valve unit 2 by means of a gas supply duct 4, between a supply aperture 4a and a delivery aperture 4b.
• the valve unit 2 comprises, in the supply duct 4, a first valve seat 5 with a corresponding first disc-type plug 6 associated with it, together with a motorized actuator, indicated as a whole by 7.
• the said actuator comprises an operating stem 8 of the plug 6 with a longitudinal axis X.
• the operating stem 8 comprises a first and a second section 9 and 10, which are coaxial with each other, are structurally independent and extend in the form of continuations of each other, and are also connected to each other by a male and female screw coupling.
• the second section 10 of the stem carries from one of its axial ends, an externally threaded shell which is screwed into a female thread formed in a blind hole of the first section 9.
• the latter section has a first portion 9a (incorporating the female thread) with an external shell having a polygonal profile which is engaged in an axially slidable way in a through hole 11 of a corresponding profile formed centrally in a rotor 12 of an electric motor 13 with a hollow shaft.
• the first portion 9a is fixed as regards rotation to the rotor and is axially slidable with respect to it, as a result of the male and female screw coupling.
• the motor 13 is preferably of the reversible stepping type.
• the first section 9 of the stem comprises a second portion 9b, which extends axially to form a continuation of the first portion and is connected to the latter in an oscillating way, and on which the first plug 6 is fitted.
• a spring 14 for taking up the axial play in the movement of the stem along the axis X is provided in the articulated connection between the portions 9a and 9b.
• the valve unit 2 is also provided with an electromagnet unit, indicated as a whole by 15, comprising an electromagnet 16 with a first part or fixed core 16a carrying a magnetizing winding and a second moving armature part 16b which can be attached by magnetization to the fixed core.
• the moving armature part of the electromagnet 16b is connected to the end of the second section 10 of the stem, opposite the threaded portion.
• the number 17 indicates a first spring acting between the stationary structure of the valve unit and the first plug 6 so that the latter tends to close the valve seat 5, in opposition to the plug raising action imparted by the motorized actuator 7.
• the valve unit 2 also comprises a second valve seat 18 formed in the duct 4, positioned coaxially with the first seat 5 and downstream of it with respect to the direction of the flow of gas.
• the second valve seat 18 is associated with a second plug 19 coupled to the first plug 6, as described more fully below.
• the second plug 19 is structurally independent of the first plug 6 and has a corresponding stem 20 carrying at one end a widened portion 21 which is axially retained by a pair of appendages 22 of the stem 8, as shown schematically in Figure 2.
• the said plugs 6 and 19 are therefore connected to each other with a limited degree of relative axial sliding, with a spring 23 acting between them.
• Guide means are provided on the stem 20 for guiding the second plug 19 coaxially with the first plug in its relative sliding with respect to the latter.
• the second plug 19 also has a truncated conical needle 24 which passes through the valve seat 18 and which can vary the gas supply cross section according to the axial sliding of the second plug 19 in the opening and closing operations, in order to regulate the flow rate through the said plug.
• the number 25 indicates a minimum duct, which has a calibrated throttle with a screw for regulating the minimum flow rate.
• the duct 25 forms a by-pass of a section of the duct 4, upstream from the valve seats 5 and 18, having a passage cross section 26 which can be shut off by the first plug 6, as described more fully below.
• the device 1 comprises, according to the invention, an electronic circuit assembly, shown schematically in Figure 1 and identified by the numerical reference 27, which is electrically connected at one end to a thermocouple sensor 28 for detecting the flame at the burner 3 and at the other end to the electromagnet unit 15 and to the motor 13 for controlling the rotation of the motor.
• an electronic circuit assembly shown schematically in Figure 1 and identified by the numerical reference 27, which is electrically connected at one end to a thermocouple sensor 28 for detecting the flame at the burner 3 and at the other end to the electromagnet unit 15 and to the motor 13 for controlling the rotation of the motor.
• the circuit assembly 27 has comparison means (not shown) for comparing the signal received from the thermocouple with a reference value and for consequently operating the electromagnet unit 15 to move the plugs 6 and 19 so that they close the corresponding valve seats, if no flame is detected at the burner 3.
• the circuit assembly is designed to cut of the electricity supply to the electromagnet 16 so that both plugs 6 and 19 are moved to close the corresponding valve seats by the elastic action of the springs 17 and 23.
• the circuit assembly 27 also has means for regulating the angular rotation of the stepping motor 13 according to a predetermined number of levels, each level being correlated with a corresponding supply flow rate (which is therefore matched to a corresponding upward travel of the second plug 19), so that the gas flow rate (and consequently the flame intensity) is regulated over the aforesaid range of levels.
• Means of setting the predetermined level are provided in the circuit assembly, with suitable push button means 29 to enable the user to select the desired level setting.
• Timing means are also provided, using an incorporated timer element, for programming the ignition and/or extinguishing of the flame at the burner 3, at the predetermined flame intensity level.
• a digital clock 30 with programming keys is provided for this purpose.
• the circuit assembly 27 is combined with a display unit 31 (one for each of the burners 3 provided) which displays the set flame level and which comprises one or more indicators 32.
• these indicators 32 are shaped in the form of a sector of a circle and are adjacent to each other, as shown in Figure 3, and their number is equal to the number of flow rate levels that can be set.
• these indicators are made to represent to the user the predetermined level between the maximum and minimum levels (arranged in the anti-clockwise direction, for example).
• all the indicators from the minimum level to the predetermined level can be backlit, to indicate the setting that has been input.
• the valve seats 5 and 18 are closed by the corresponding plugs 6 and 19, as a result of the elastic action of the springs 17 and 23.
• the electromagnet 16 is de- energized and no current is supplied to the motor 13.
• the motor 13 is initially operated for a predetermined number of angular steps, the total extent of which is correlated, by means of the thread pitch of the male and female screw coupling, with a predetermined axial travel of the second section of the stem.
• the travel of this section of the stem is such that the moving armature 16b is brought up to the fixed core 16a of the electromagnet, in the proximity of the area of electromagnetic attraction.
• the subsequent energizing of the electromagnet generates an electromagnetic attractive force which can keep the armature 16b attached to the fixed core in the position shown in Figure 2.
• a subsequent rotation of the motor 13, in the opposite direction to the preceding rotation, causes the first section to be screwed on to the second section of the stem, causing a relative axial sliding of the first section and the consequent movement of the first plug 6 away from the seat 5, in opposition to the action of the spring 17, with the corresponding opening of the seat 5.
• the second plug continues to close the second seat until the first plug has been raised through a distance equal to the axial relative sliding play between the plugs. When this travel has been completed, the further rotation of the motor causes both the plugs to be raised together so that the corresponding valve seats are opened.
• this initial opening causes the supply to be provided at the maximum flow rate, since the needle 24 is in such a position as to form a maximum cross section of passage of the gas through the second valve seat.
• the supply flow rate is regulated at the desired level with consequent regulation of the flame intensity. This regulation makes it possible to move from maximum flow rate to minimum flow rate, through a predetermined number of intermediate values (levels).
• the first plug 6 In conditions of minimum flow rate, the first plug 6 is moved so that it closes the passage cross section 26 and the gas flows in the minimum duct 25, thus providing the minimum flow rate according to the preset calibration.
• thermocouple signal is converted by the circuit assembly into a signal for cutting off the electricity supply to the electromagnet unit, so that the plugs 6 and 19 close the seats 5 and 18 as a result of the elastic action of the springs 17 and 23. This action is always guaranteed, regardless of the position of the motorized actuator.
• the spring 17 is designed with a size and elastic constant such that the safe closing of the valve seats by their respective plugs is guaranteed, regardless of the axial position which the operating stem has reached.
• the spring 23 acting between the plugs has characteristics which ensure that an elastic closing force is applied to the second plug 19, independently of the first plug 6.
• the motor 13 in conjunction with the cutting off of the electricity supply to the electromagnet 15, the motor 13 may be caused to rotate in such a way that, together with the elastic action of the springs, it helps to move the plugs towards the corresponding valve seats, until the seats are closed if necessary, in such a way that a double action is provided to achieve the condition in which the gas duct is shut off.
• the ignition, regulation and extinguishing of the flame are caused, by the programming means, to take place with a time delay or according to sequences programmed by means of the desired settings.
• a principal advantage consists in the fact that the device according to the invention provides a wider range of functions, in terms of regulation and programming of the flame intensity, while providing a safety shut-off system based on reliable thermomagnetic means and conforming to the relevant standards.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Feeding And Controlling Fuel (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=33428289

Family Applications (1)

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Family Cites Families (7)

• 2003
  • 2003-05-09 EP EP03727943A patent/EP1623157A1/de not_active Withdrawn
  • 2003-05-09 AU AU2003233188A patent/AU2003233188A1/en not_active Abandoned
  • 2003-05-09 WO PCT/IT2003/000280 patent/WO2004099669A1/en not_active Ceased

Non-Patent Citations (1)

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