FR2462660A1 - IMPROVEMENTS TO DEVICES TO CONTROL SAFELY GAS VALVES - Google Patents

Abstract

1. Control device for opening a gate (1) able to deliver a pressurized combustible gas, said control being made by closing an electric switch (3) and setting normally in action, successively, excitation of a first relay contactor (2) intended to open the gate (1) by feeding it with an electric voltage (10), actuation of an igniter (5) of said gas, detection (6) of the flame corresponding to the so ignited gas, automatic closing of said gate (1) if said detection is not actual at the end of an opening period T0 of said gate and excitation, in the contrary case, of a second relay contactor (7) with several movable contacts (71 , 72 ) mounted so as to stop the working of the igniter (5) and to maintain the electrical feed of the gate (1), beyond the period T0 , by an alternating voltage (8) rectified through contacts (21 , 71 ) and a rectifier (9), a protection circuit-breaker (14) being mounted so as to be blown out and to consequently cut said feed (8) if one of the movable contacts (71 , 72 ) of the second relay contactor (7) is in an inadequate position on starting, characterized in that, in view of automatically blowing out said circuit breaker (14) when any one said movable contacts (71 , 72 ) of the second relay contactor (7) is in its working position while the first contactor (2) is in its resting position, each of said movable contacts (71 , 72 ), in its working position, serially connects the voltage source (8), the circuit-breaker (14), one closed contact (21 ) of the first relay contactor (2) in its resting position and rectifier means (respectively 15, 16 and 17, 18) allowing flowing of a rectified current in the sense opposite to that of the current which normally feeds the gate (1) beyond each period T0 .

Description

The invention relates to devices for

  control of the opening and closing of a

  no fuel gas, including a water heater burner, bath heater or hot water central heating boiler, command to be automatically translated by closing said valve after a predetermined delay T after its opening if the gas under pressure delivered

  by this valve was not lit in the meantime.

  In particular, it aims at

  those whose order is ensured by the closure of a

  electrical control switch and puts into play successive-

  the excitation of a relay contactor to open

  the valve by applying to it a rectified voltage or

  the ignition of the pressurized gas distributed by the

  thus not open, the detection of the flame corresponding to the gas thus lit and the automatic closing of said valve if this detection is not effective at the end of the delay T.

  Its purpose is, above all, to make "posi-

  the safety of these valve control devices, in the sense that any failure of these devices results in

  automatically by closing the corresponding valves.

  The control devices of the kind in question se-

  The invention is essentially characterized in that it comprises, in addition to the relay contactor excited from the closure of the control switch and arranged to open the valve by applying to it a rectified voltage or continuous for a maximum duration equal to To, a second relay contactor controlled by the flame detection due to the combustion of the gas dispensed by the valve thus opened, arranged to relay the first contactor to open the valve as soon as this detection is effective

  by applying in turn on this valve a reduced tension

or continue.

  In preferred embodiments, one or more of the following provisions are also used: the blocks which are connected by each of the contacts of the second relay contactor when the power supply of the the valve is ensured through them, are, as long as the first

  contactor is not energized, connected in series with a

  this of rectified or continuous voltage mounted in reverse so that, if one of these contacts is not in its

  rest position before the actual ignition of the gas, a short

  circuit is automatically created, blowing a protective circuit breaker element, - in a control device according to the preceding paragraph, the tripping of the first contactor is posterior of a short delay t0 at the closing of the control switch, - in a control device according to at least the preceding paragraph, the excitation of a gas igniter is effected through a rest contact of the second contactor, - there is provided a protection circuit breaker arranged so

  to be triggered after a period T1 consecutive to the former

  quote of the first contactor if the second contactor has not been excited during this period T1, and the circuit which

  ensures the excitation of the first contactor from the iron

  of the control switch comprises an electric locking member capable of being rendered conductive - exclusively by lighting from a light element

  electrically powered through the sensitive element of the disc

  in a control device according to the preceding paragraph, the power supply of the circuit breaker is made through a contact at rest of the second contactor, - the power supply of the valve due to the excitation

  first contactor is made by simply discharging a condensate

  in accordance with French patent EN 79 19763 filed

  August 1, 1979 by the plaintiff.

  The invention comprises, apart from these main provisions, certain other provisions which are used

  preferably at the same time and-of which it will be more explicit-

question below.

  In what follows, we will describe a mode of

  preferred embodiment of the invention with reference to the drawing

  attached in a way of course not limiting.

  The single figure in this drawing shows, very schemati-

  a fuel gas valve control device

  established in accordance with the invention.

  The valve 1 to be controlled is suitable for dispensing a gas

  fuel under pressure at the burner of a gas appliance

  bustible such as, in particular, a water heater, a heater baths

  or a central heating boiler with hot water.

  This is a safety valve in that it

  opens only when applying a

  continuous or rectified V, any lack of power

  electric valve of this valve resulting in its closure.

  In a manner known per se, the application of this voltage V to the valve 1 is provided by the excitation of a relay contactor 2, excitation itself controlled by the closure

  an electric control switch 3.

  This closure is itself enslaved to the circulation of

  water in the heater of the gas appliance,

  circulation due to the drawing of hot water (in the case of

  water or hot water heater) or when starting a circulation pump 4 (in case of central heating boilers): for this purpose, a depression created by this circulation is

  operated by a differential valve system for action-

said switch 3.

  When valve 1 is opened, it distributes to

  burner of the device a combustible gas under pressure.

  We synchronize with the beginning of this opening the ex-

  quote of a lighter 5 to turn on the gas-thus dispelled

  tributed. The importance attached to the effective ignition of this gas is known: in particular, if this ignition is not ensured after a period T (between 1 and 5 seconds),

  preferably of the order of 3 seconds) following the opening

  the valve, the valve must close automatically.

  matically. It is therefore expected a flame detector 6 for verification

  whether the ignition in question is effective or not and it is only

  in the event that ignition is obtained before expiry

  ration of the period T that means enslaved to the output of this detector maintain the power supply of the

  valve 1: timing means or the like are provided

  seen to stop the application of the voltage V on the valve, due to the simple excitation of the contactor 2, at the end

of the period T0.

  The object of the invention is to ensure the total positive security of such an assembly in that any

  translate automatically by closing the valve.

  The means enslaved to the output of the flam-

  Me 6 themselves include a second relay contactor 7 clean, too, to apply to the valve 1 a DC or rectified voltage V 'own to open this valve, voltage

  having the same amplitude as the voltage V, but

  possibly in a different way.

  In the present case, this voltage V 'is that W

  generated by the network or sector 8 (generally know an alternating voltage of amplitude 220 volts) and rectified at

  through a unidirectional member 9 such as a diode.

  (For the sake of simplicity, this unidirectional

  nel and those of the same kind will be designated in the following by the term "diode", but in a nonlimiting manner, all other unidirectional members or rectifiers may

  also be considered to constitute them).

  Voltage V, for its part, could be generated by

  analogous to the voltage V 'through a time

appropriate porization.

  But it is preferably generated here from the

  which has been taught in the above-mentioned France patent, that is by discharging a capacitor 10 through a

  diode 11, this capacitor being itself, before actuation-

  contactor 2 or more generally as long as it is not excited, charged from sector 8 through a diode

12 and a load resistor 13.

  For the above system to be safe, it is necessary to

  that the second relay contactor 7 is triggered uni-

  in response to actual flame detection.

  In particular it is necessary that this trigger

  is not caused by simulation of a flame, that is,

  say by issuing an electrical signal developed falsely

  by the detector 6 even before the opening of the valve 1.

  It is also necessary that the moving contacts of this contactor 7 have returned well to their position of

  rest after the previous operation of this switch.

  Total security with respect to each of these two defects is automatically ensured, according to the invention, by mounting in series each of said movable contacts, when

  are in their active position (that is, correspond to

  in the excited state of the contactor 7) and that both the first contactor 2 is at rest, with a source of

  continuous or rectified voltage mounted in the opposite direction,

  cause a short circuit to blow a fuse

  14 of protection of the installation.

  In the figure, the contacts in question, two in number, have been designated by the references 71 and 72 The first contact 71 is connected across the sector 8 through a contact at rest 21 of the contactor 2 and two diodes 15 and 16 in series, both mounted in the opposite direction of the diode 9, the diode 15 being further mounted in

parallel on the valve 1.

  As for the second contact 72, it is connected to the terminals of the sector 8 also through the contact 21 at rest and two other diodes 17 and 18 also mounted in series and in sense

inverse of the diode 9.

  The operation of this security is as follows.

  When starting the installation, while the first

  first contactor 2 is still at rest, the second contactor 7 must be also, the excitation of the latter being provided after ignition of the gas dispensed by the valve 1,

  then detection of this ignition at 6, which supposes that

  said valve is opened by the excitation of the first contact

2.

  So if one of the contacts 71 and 72 is then in

  its working position is that there is a certain defect

  that part, either that said contact has remained "glued" after a previous operation, or that the detector 6 has developed prematurely an excitation signal of the contactor

  7, similar to that due to the presence of a flame: this de-

  must is immediately sanctioned by the creation of a short circuit through the contact in a bad position,

  short circuit that blows the fuse 14.

  It is then necessary to call on a repairer to

  to start the installation after identification and elimination

of the defect.

  The control just described can be carried out

  se immediately after closing the main switch

  19 or after closing switch 3, but before

  first contactor 2, a small delay t0, by

  example of the order of the second, being advantageously

  seen to this effect between these last two orders.

  In the same vein, a diode 20, connected in parallel with the capacitor 10, in the same direction as the diode 15, makes it possible to detect, by breaking the fuse 14, a

  undesirable "bonding" of the contact 22 of the contactor 2 to its po-

  work through the sequence of components

  LEDs: diode 11, contact 71 at work, diode 16 and contact

21 at rest.

  Any unwanted "collages" of the latter

  contact 21 in its working position are controlled from one

  the way that will now be described.

  If after a period T1, for example of the order of

  seconds, following the outbreak of the first contact

  2, the second contactor 7 has not been triggered is that the flame detection to which is enslaved it

  trigger was not observed.

  In this case, the valve 1 has been closed at the end of the period T0 which is shorter than the period T1 and starts at the same time as this period, but the installation remains under

  voltage: it must then be disconnected and trigger an alarm.

  to make an external intervention necessary in order to

  the breakdown repair (which may be due to a

  be a phenomenon that a defect of ignition, for example to a man-

than gas).

  For this purpose, a circuit breaker 21 is provided, in particular

  thermal or timed type, having the same role as fusing

  14 above and whose sensitive element (at the temperature

  or time) is energized as soon as the first

  factor 2 from sector 8 through contact 21 to

  work, a diode 22 and the contact 72 at rest.

  The integrity of this circuit of supply of the disjunc-

  is of great importance.

  For its eventual cut-off to prohibit the

  of the installation, use is made of

  of the invention, to the following stratagem.

  The coil of the contactor 2 is electrically excited, under the control of the switch 3, from the secondary of a transformer 23 whose primary is powered by the

sector 8.

  This power supply is performed through an optoelectronic barrier member schematized on the drawing by a

  photothyristor 24 whose door is connected to a resistor

this 25.

  This dam can only be removed if the element

  tosensible 24 is illuminated from a lamp 26, such as

  a photoluminescent diode, which lamp can not be

  electrically, from the sector, only through

  the sensitive element of the circuit-breaker 21, as well as across the diode

of 22 and the contact 72 at rest.

  This optical coupling between the lamp 26 and the photosensitive element 24, shown schematically by the broken arrow 0, makes it possible to selectively and surely transmit an instruction of a circuit under medium voltage (220 volts) to a circuit under

  low voltage (for example 24 volts), without

a disturbance to these circuits.

  With this arrangement, the first contactor 2 does not

  can be excited only if the circuit breaker 21 and its circuit

  are intact and ready to fulfill their protection mission, which is a major new

The invention.

  In addition, there is evidence that a possible unwanted "collage"

  the contact 21 in its working position translates into

  supply of the circuit breaker 21 in the manner indicated below.

  above, which triggers the latter if the real ignition of the gas does not cause the excitation of the second relay 7 before

  the end of a period T1 consecutive to said collage.

  We still see in the drawing: - a resistor 27 mounted in series with the lamp 26, - another resistor 28 connected in series with the igniter 5 and with a diode 29 mounted in the same direction as the diode

  9, the value of this resistor 28 being clearly superior to

  res to that of the resistor 27 so that the lamp 26 can not be fed sufficiently, to ensure its

  role of verification, only through the sensitive element of

  21 and not through the resistor 28, too high, which is connected in parallel to this sensitive element as the switch 7 is at rest, - a variable resistor 30, for adjusting the duration T1, mounted in series with the sensitive element of the circuit breaker 21, the assembly of this variable resistor and this sensitive element being mounted in parallel on the diode 17 above, - a light indicator 31 mounted in parallel on the elements

  14 and 21, so as to signal the break-up of one of these

ments,

  - and a rectangle E symbolizing all the elec-

  tronics, some to transform the information "

  flame detection "of the detector 6 in the electrical excitation of the contactor 7, and the others to develop, in combination with the two components 24 and 25, the electrical excitation of the 2Q contactor 2 from the secondary of the transformer 23

  when closing the switch 3.

  As it goes without saying and as it follows from elsewhere

  Here, the invention is in no way limited to those of its modes of application and realization which have been more especially envisaged; it embraces, on the contrary,

  all the variants, in particular those where the photosensitive element

  sible 24 would not be a photothyristor, but a phototran-

  sistor, a resistance then being provided between the two dishes intended to coagulate alternately with the moving contact 72

according to the position of the latter.

Claims (7)

  1. Device for the controlled control of the opening   of a fuel gas valve, said control being   ensured by closing an electrical switch and   both in the game successively the excitation of a relay contactor own to open the valve by applying on it a   rectified or continuous voltage, the ignition of the gas under pres-   distributed by the valve thus opened, the detection of the flame corresponding to the gas thus ignited and the closure   automatically of said valve if this detection is not ef-   fective at the end of a period T of opening of this valve,   characterized in that it comprises, in addition to the contactor re-   above (2), a second relay switch (7) asserts   vi to the detection (in 6) of the flames due to the combustion of the gas distributed by the open valve (1) and arranged in such a way as to   relay the first contactor for opening the van-   as soon as this detection is effective by applying to its   turn on this valve a rectified or continuous voltage.   2. Control device according to claim 1, characterized in that the pads which are connected by each of the movable contacts (71 7 2 of the second relay contactor   (7) when the power supply to the valve is   thru through them, are, as long as the first contactor (2)   is not excited, connected in series with a source of voltage.   rectified or continuous reverse-rise (8, 15, 16; 8, 17, 18) so that if one of these contacts is not in its rest position before the actual ignition of the gas, a short circuit is automatically created, blowing a   circuit breaker element (14).   3. Control device according to claim 1, characterized in that the tripping of the first contactor (2) is posterior of a short delay to the closing of the control switch (3).   4. Control device according to any one of   Claims 1 and 2, characterized in that the excitation   a gas igniter (5) is made through a contact   at rest (71) of the second contactor (7).   5. Control device according to any one of   preceding claims, characterized in that it comprises   a protection circuit-breaker (21) arranged to be de-   latched at the end of a period T1 consecutive to the excitation of the first contactor (2) if the second contactor (7) has not been excited during this period T1, and in that the circuit which ensures the excitation of the first contactor from the closing of the control switch comprises an actuator   electric lock (24) which can be made conductive   exclusively by lighting from a light element   (26) powered electrically through the sensing element said circuit breaker.   6. Control device according to claim 5,   characterized in that the power supply of the disjunc-   tor (21) is effected through a rest contact (72) of the second contactor (7); 7. Control device according to any one of   previous claims, characterized in that the food   the valve due to the excitation of the first   contactor is made by simply discharging a condensate   (10) according to the teachings of the French patent No. 79,19763.