FR2517809A1 - HEATER WITH BURNER AND PILOT FLAME - Google Patents

Abstract

A BURNER 10 INCLUDES A VENTURI 11 AND A HAT 13 PROVIDED WITH HOLES 15 FOR MAIN FLAMES. THE VENTURI 11 IS SUPPLIED WITH GAS FROM A TAP 22, WHICH CAN BE MANUALLY ACTUATED, THROUGH A CONDUIT 20 INCLUDING A VALVE 24 ACTUATED BY A CONTROL DEVICE 25 TO OPERATE BURNER 10 INTERMITTENTLY. AN ADDITIONAL VENTURI 52 SUPPLIES PILOT ORIFICES 48 PROVIDED IN THE HAT 13 OF THE VENTURI BURNER BEING SEPARATELY CONNECTED TO THE TAP 22 SO THAT THE PILOT FLAMES CONTINUE TO BURN DURING THE MAIN FLAME EXTINGUISHING PERIODS.

Description

The present invention relates to a provision

  heating sitive of the type comprising a burner and a device

  positive control of the gas burner supply

  adapted so that during a heating period the burner

  be switched on and off alternately at intervals

  determined by the control device, the burner

  taking a main venturi which communicates with a cha-

  skin comprising a mixing chamber and orifices

  for the main burner flames.

  French Patent No. 2,418,910 has been described

  a burner which is connected to a collector by means of

  diary of a gas valve which is actuated by a

  positive command to open and close alternately

  the gas supply to the burner, at predetermined intervals-

  mined The control device includes a disc

  mant cam which is rotated by an electric motor The cam has a ramp which cooperates with a valve actuator to open and close the valve Another cam ramp provided on the cam disc cooperates with a generator

  of sparks which includes an igniter placed in the vicinity

burner age.

  When operating intermittently

  this burner is lit repeatedly by sparks

  those, and the valve must be opened a few moments before the spark generator is actuated. As a result, a small amount of unburned gas is emitted each time the burner goes from its extinguished state to its lit state. burner is operated intermittently for a fairly long time, gas can accumulate and contaminate the surrounding atmosphere

  which at the very least can be unpleasant.

  Another drawback relates to the fact that there is a thermocouple intended to be heated by the flames of the burner in order to keep open

  a safety valve, the latter cutting off the supply

  gas if the burner goes out and stays off during

  2- for a predetermined duration The burner must be turned on again before the electromotive force of the thermocouple has fallen below a predetermined value for which the safety valve must cut off the gas supply Consequently the period of extinction of the burner depends on the characteristics of the thermocouple and, with the thermocouples available on the market, the useful range of the possible settings

heating is limited.

  An additional drawback relates to the fact that during intermittent operation a large number of sparks are emitted, which causes noise.

  The main object of the invention is to suppress

  sea the aforementioned drawbacks and to realize a disposi-

  heating element comprising a burner which can be

  operated intermittently without the need for

  re emitting noisy sparks and without limiting them

  tions caused by the short period of fall of the

this thermocouple electromotive.

  The object of the invention for this purpose is a provision

  heating device of the type comprising a burner and a control device, for controlling the supply of gas to the burner so that during a heating period the burner is alternately ignited and extinguished at intervals determined by the control device, the burner comprising a main venturi communicating with a head having a mixing chamber and orifices for the main flames of the burner,

  characterized in that it includes an additional room

  -mixing plate provided in the burner cap, this-

  te room communicating with at least one opening for

  a pilot flame, said additional metering chamber

  diaper being supplied separately with gas through the

  diary of an additional venturi so that the

  pilot flame also burns during periods of

burner shutdown.

  -3- Other features and advantages of

  the invention will appear during the description which

  will follow made with reference to the accompanying drawing given solely by way of example and in which: FIG. 1 is a diagram in part in section of a burner according to the invention and of its control members; Fig 2 is a sectional view along the

line II-II of Fig l.

  There is shown in Fig l a burner designated as a whole by the reference 10, which comprises a

  venturi 11, a head 12 and a cap 13 The head

  poses freely on a shoulder 14 of the venturi and the cha-

  skin 13 rests on the head Holes 15 are provided in the burner cap for the main flames and in a conventional manner orifices 35 are provided

  for secondary flame stabilizing the main flame

  pale The burner cap also includes a chamber

  of mixture 17, part of which is delimited by a part

horizontal king 18 of head 12.

  The venturi 11 is supplied with gas by an injector

  valve 19 disposed at the end of a gas conduit 20 which is connected to a manifold 21 by means of a tap 22 actuated by a button 23 A valve 24 mechanically actuated is interposed in the conduit to allow intermittent operation of the burner 10 A device is provided for this purpose.

  control 25 comprising a disc 26 forming a cam

  carrying a ramp 27 acting on a pusher 28 which

  actuates the valve 24 P a c a m e 2 6 is in-

  drag in rotation by an electric motor 29 and the

  configuration of the cam ramp 27 determines the

  Riodes in which the valve 24 is respectively open and closed The motor is connected to a power source by a terminal box 30 comprising terminals 31 and 32 A first terminal 33 of the motor is connected to terminal 32 by a conductor 34 and a second terminal 35 of the motor is connected to terminal 31 by

  a conductor 36, a microswitch 37 and a conductor 38.

  The motor terminal 35 is further connected to the terminal 31 by means of a conductor 39, a switch 40 actuated by a push button and a conductor 41. The microswitch 37 carries a member d actuation 42 which cooperates with an additional cam ramp 43

  provided on the disc 26 forming a cam, said additional ramp

with a protrusion 44.

  To prevent gas being emitted in the event that the burner flames are extinguished, the valve 22 includes an integrated solenoid valve 45 actuated by an electromagnet which is controlled by a thermocouple 46 disposed near the burner, so as to be heated by flames When the thermocouple is heated, a force

  electromotive is generated which keeps the electric open

  valve 45 If the burner goes out or the gas supply is cut off for some other reason during a

  period exceeding a predetermined duration, the electric force

  tromotor falls below the maintenance level and the

  solenoid valve 45 closes and permanently cuts the

  gas supply An electric igniter 47 consisting of a spark plug is provided for the initial lighting of the burner or for lighting it again if the

  burner has been turned off due to actuation of the

solenoid valve 45.

  During intermittent operation the burner must be ignited automatically under the control of the control device 25 and for this purpose the invention uses pilot flames continuously burning, which

  are formed by three pilot orifices 48 which are equally

  spaced around the periphery of the burner Each orifice 48 is connected to a central mixing chamber 49 formed in the cap 13 of the burner by means of a passage 50 having an inlet orifice 51 of cross section

  reduced The mixing chamber is supplied with a medium

  lange of air and gas by a separate venturi 52 which is supplied by an injector 53 disposed at the end of a duct 54 which is connected to the tap 22 The pilot flames leaving the orifices 48 are used only for

  ignition and should not cause noticeable heating

  any cooking container for periods of time

  burner shutdowns To eliminate this problem of direct heating, the burner cap 13 has a peripheral rim 55 which extends beyond the orifices 48 over a distance which corresponds at least to the length of the pilot flames In addition, the upper part of the

  burner cap has a thickness which is chosen

  so that the hat absorbs its energy

  transferred by pilot flames.

  The burner described above works

  as follows: to light the burner 10, we turn

  do the button 23 in a valve 22 adjustment position for a predetermined gas flow However, the solenoid valve inserted in series must also be open to allow the gas to pass through the valve 22 For this purpose a

  push on button 23 mechanically opens the electric

  valve 45 A valve of the type described, comprising a

  safety valve activated by a thermocouple is available

  ble on the market and will therefore not be described in

  details At the same time as pushing button 23, a button-

  push button (not shown) is actuated to operate

  activate the igniter 47 so that it emits sparks to ignite the gas leaving through the orifices 15, 16 and the orifices 48 of the cap 13 As soon as the thermocouple

  has been heated by flames from the burner,

  so after a period of between 4 and 6 seconds, the button 23 can be released and the voltage required to keep the solenoid valve 45 in operation is generated by the thermocouple This initial process is the same, whether the burner is set for continuous operation or for

intermittent operation.

  Intermittent operation is started

  by actuation of the switch 40 to connect the mo-

  tor 29 to the sector represented by the terminals 31, 32 In the rest position of the cam 26, the ramp 27 keeps the pusher 28 and the valve 24 open, which is a

  condition for continuous operation of the Cepen- burner

  dant, the rotation of the cam 26 compels the projection of the ramp 27 to release the pusher 28 which closes the valve 24 and thereby cuts the gas supply to the main orifices

  blades 15 and pilot stabilization orifices 16 Pen-

  during the main flame extinction period, the

  pilot ignition flames from orifices 48

  due to the fact that these ports are supplied with

  facing The thermocouple is arranged to be heated

  by a pilot flame coming from an orifice 48 which pro-

  cure the advantage that periods of operation and

  are independent of the fall time of the electric force

  tromotor generated by the thermocouple 46 When the pusher 28 is actuated again by the projection 27 of the cam, the valve 24 closes and the main burner represented by the orifices 15 is ignited by the flames

pilots from ports 48.

  Intermittent operation is stopped by opening the switch 40 However, a parallel circuit constituted by the conductor 36, the microswitch 37, the conductor 38, the terminals 31 and 32 and the conductor 34 keeps the motor running until the

  cam disc is in the position shown

  shown in FIG. 1 in which the projection 44 acts on

  arm 42 to open microswitch 37.

  It appears from the foregoing description of the mo-

  of preferred embodiment of the invention than the fact of

  provide pilot flames to light the burner during

  During intermittent operation is advantageous in that the sparks which would otherwise be necessary in this operating mode can be eliminated. In addition, the relationship between the burner ignition periods and the burner extinction periods can be chosen independently of the characteristics. thermocouple 46 and

the solenoid valve 45.

-7

Claims (5)

CLAIMS -   1 heating device including a burner   (10) and a control device (25) for controlling the a-   gas supply to the burner so that during a   heating period the burner is alternately lit   on and off at intervals determined by the device   control, the burner (10) comprising a main venturi   pal (11) communicating with a burner cap (13) having a mixing chamber (17) and orifices (15) for the main burner flames, characterized in that it comprises an additional mixing chamber (49) provided in the burner cap (13), this chamber communicating with at least one orifice (48) to form a pilot flame, said additional mixing chamber   (49) being supplied separately with gas by a venturi sup-   extra (52) so that the pilot flame burns   also during burner shutdown periods.   2 Device according to claim 1, characterized in that the additional mixing chamber (49) is located in a central position, three orifices (48) for pilot flame outlet being also spaced   on the periphery of the burner cap (13), each orifice   this (48) communicating with the additional room of   mixture (49) by passages (50, 51) extending radially-   is lying. 3 Device according to any one of   claims 1 or 2, characterized in that it comprises a   first valve (22) which can be actuated manually, which is connected directly to the additional venturi (52) and to the main venturi (11) via a valve (24) controlled by the control device (25),   the valve (22) being provided with an action- safety valve   born by a thermocouple (46) arranged so as to be heated by one of the pilot flames   4 Device according to any one of. 8 -   previous claims, characterized in that the   burner cap (13) has a peripheral rim (55) which extends radially beyond the orifice (48) pilot flame.   5 Device according to claim 4,   characterized in that said peripheral rim (55) extends   tends radially over a distance which corresponds at least to the length of the pilot flame.