FR2593270A1 - POWER REGULATOR FOR GAS BURNER AND ITS COMBINATION WITH A BURNER - Google Patents

Abstract

The regulator according to the invention is remarkable in that it has two separate circuits for air and gas respectively, each circuit comprising an inlet orifice 10 '', 13 '' and an outlet orifice 10 ', communicating between them by at least one slot 11 ', 11' 'and 15, the inlet ports being intended to be connected to means for supplying the fluids respectively air and gas and the outlet ports being intended to be connected to the burner, while the ports can each be more or less closed depending on the displacement of a shutter 18, 19 movably disposed in the regulator. (CF DRAWING IN BOPI)

Description

The invention relates to a feed regulator for a

  gas burner and its combination with a burner.

  To modulate the average power of a burner intended, for example, to heat the water of a heating installation, it is obviously known to operate said burner intermittently, that is to say in operation in "all or nothing"

  based on "on-off" sequences.

  This type of operation is generally harmful because of thermal shocks, variations of expansion and pressure and wear of the various components (electrodes, solenoid valves, relays, etc.) whose lifetime is generally calculated over a maximum number of maneuvers. In addition, in order to reach a desired temperature quickly, it is

  sometimes it is necessary to oversize the exchanger.

  That is why, even if we keep a functioning "on-off", it is useful to be able to modulate the power of the

burner in operation.

  To vary the power of a gas burner, it is sufficient to modify the output flow of the air-gas combustion mixture between a minimum and a maximum, the limits of which are observed respectively by flamebacks and

  flame stall at the combustion grate.

  In addition, it is known that the combustion efficiency of a gas burner essentially depends on the stoichiometric air-gas mixture and therefore on the ratio of proportions of these two fluids, which must remain substantially constant and equal, and at a value of

  determined (eg air-gas ratio equal to 10).

  Since it is very difficult or impossible to modulate the output flow of the mixture at the level of the combustion grate, an attempt has been made to perform a modulation on the flow rates

supply of gas and air.

  There are two basic types of gas burners:

  atmospheric burners and pre-mix flame burners.

  The atmospheric burners allow a combustion with an excess of air whose control of the flow is very difficult, so that it is not possible to maintain a constant ratio between the proportions of air and gas, the efficiency of

  combustion is thus variable and not optimized.

  In pre-mix flame burners, there are control systems designed to regulate the ratio of air and gas flow rates while permitting variation in the flow rate of the mixture. These systems allow regulation called "zero regulation" by controlling the flow of gas to the air intake, this

  last being modulated according to the desired temperature.

  Regulators for these systems are complex and expensive (particularly requiring membranes and valves) and have drawbacks, especially at low power. Moreover, and above all, these known systems make it possible to vary the flow rate of the air-gas mixture and therefore the power,

only in small proportions.

  It is also important to note that a ratio of the air and gas flow rates at the burner inlet does not necessarily result in the same ratio of air-to-gas ratios in the output mixture on the combustion grate given the

  aeraulic resistance of the burner for each of these fluids.

  In addition, a variation in the ratio of feed rates does not cause the same variation in the ratio of proportions of the fluids in the mixture so that, to obtain a variation in the flow rate of the combustion mixture while maintaining a stoichiometric proportion of said mixing, it is usually necessary to vary the feed rates

  of air and gas in a non-constant ratio.

  This is why the inventor has sought and imagined a feed regulator of a gas burner that allows a power modulation in the best yield conditions and in a wide range of variation, while

  being simple, reliable and inexpensive.

  The gas burner supply regulator according to the invention is remarkable in that it has two separate circuits for respectively the air and the gas, each circuit comprising an inlet orifice and an outlet orifice communicating with each other by at least one light, the inlet orifices being intended to be connected to means for supplying the fluids, respectively air and gas, and the outlet orifices being intended to be connected to the burner, while the lights may be more or less each closed as a function of the displacement of a shutter movably disposed in the regulator. According to a preferred embodiment, the shutters of the two air and gas circuits are mechanically interconnected to form a single slide, the displacement of which provides the

  simultaneous movement of the two shutters.

  For example, one of the lights may have, on at least a part of its length, parallel sides so as to disengage a passage section during the displacement of the shutter on this portion which is directly proportional to said displacement while the drawer can be movably mounted in translation and movable by a control and adjustment means

step by step or continuously.

  Advantageously, the regulator has two identical air passage lumens, coaxial with each other and with the air inlet and outlet orifices, and two respectively inlet and outlet gas chambers which each communicate with the orifices respectively. gas inlet and outlet while said gas inlet and outlet chambers are separated from each other in a sealed manner by a light carrier member for the gas and that the drawer is slidably mounted in such a manner that the shutters of air and gas respectively slide between the air lumens and in front of the gas lumen. Preferably in this case, the regulator is formed by two shells assembled together and each provided with one of the air slots and its corresponding inlet or outlet air outlet and one of the chambers respectively. gas inlet or outlet and its corresponding gas inlet or outlet orifice while the gas light-carrying member and the sliding drawer are disposed between the shells in a

  groove provided for this purpose in each of the shells.

  According to a particular embodiment, the light-carrying member for the gas has a shape adapted to the shape of the gas inlet and outlet chambers that it separates in a sealed manner, and said element is provided with a slot, passing through its central portion, and a bore, of a diameter at least equal to the width of the slot and which is formed in its thickness to communicate with said slot while the gas shutter is formed by a pin of corresponding shape to said bore in which it slides to close more or less said slot and that the air shutter is

  formed by a plate integral with said pin.

  In addition, and preferably, the gas inlet and outlet ports are arranged along parallel axes which are perpendicular to the common axis of the air openings and orifices.

inlet and outlet air.

  The regulator according to the invention is adaptable to several types of burner. It is particularly well suited to equip a burner which is provided with an air inlet communicating with a mixing chamber in which opens an inlet centrally

  of gas and under which is arranged a combustion grate.

  The invention also relates to a burner equipped with a

regulator according to the invention.

  A burner of the type mentioned above is remarkable, according to one embodiment of the invention, in that the respective air and gas outlet ports of the regulator are connected to the respective air and gas inlets. burner while at least one annular baffle is arranged in the air circuit of the burner before the arrival thereof in the mixing chamber and at least one annular baffle is arranged in the mixing chamber, in order to constitute baffles in the paths traveled respectively by the air and

by the air-gas mixture.

  The invention will be well understood on reading the

  description which follows and which refers to the attached drawings

  in which: - Figure 1 shows schematically in section a burner equipped with a regulator according to the invention, - Figure 2 shows in top view one of the constituent shells of the regulator equipped with a drawer and a light door element for the gas (shown in section); - FIG. 3 is a section on III-III of FIG. 2 but on the entire regulator (formed of its two shells); and FIG. according to IV-IV of FIG.

  also from the entire regulator.

  As shown in Figure 1, a gas burner 1 is

  supplied with gas and air by means of a regulator 2.

  The regulator 2 is itself supplied with air by a fan 3 and returns air to the burner by a sleeve 4, while the gas arrives at said regulator via a pipe 5, itself connected to a pressure regulator (not shown) and returns the

  gas to the burner via a pipe 6.

  As shown in the drawings, the regulator 2 is formed of two similar shells 2 'and 2 "(FIGS. 1 to 4), assembled together by any means such as screws, screwed into corresponding threads represented at 7 in FIG. , this last figure representing as already said one of the shells

(in this case the shell 2 ').

  In each shell 2 ', 2 ", various recesses have been made, said shells each comprising in particular a large groove 8, 8', open on one side, intended to form, after assembly of the shells 2 'and 2", a housing in which can

  slide a drawer 9 (see in particular Figure 3).

  Each shell 2 ', 2 "11 has an orifice, respectively 10', 10" which opens on a light 11 ', 11 ", the shells being assembled in such a way that the orifices 10', 10" and the

25932? O

  lights 11 'and 11 "are coaxial as shown in FIG.

  Each of the shells further comprises a chamber 12 ', 12 "(FIGS. 3 and 4) open in the corresponding groove 8', 8" and which communicates with the outside through a lateral orifice 13 ', 13 "respectively whose axes are perpendicular to the common axis of the orifices 10 ', 10 "and the slots 11', 11", while the said chambers are arranged by their open part above one another and separated by a light-holder element 14 who

  is housed at the end of the housing formed by said grooves 8 'and 8 ".

  The light-carrying element 14 of adequate shape is arranged between the chambers 12 'and 12 "in a sealed manner by means of O-rings 17 (FIGS. 3 and 4) while it comprises a

  slot-shaped light 15 which passes through it from one side to the other.

  The element 14 further comprises, in its thickness, a bore 16 (FIG. 4) of a diameter at least equal to the width of

  the slot 15 in which it extends.

  The drawer 9 already cited comprises a plate 18 secured to a pin 19, a diameter corresponding to the bore 16 of the element 14. The plate 18 is arranged to slide between: the grooves 8 'and 8 "in driving the pin 19 which slides in said bore 16. The pin 19 is for example screwed into the wafer 18, or it is arranged as an insert during molding of said wafer, a groove 23 (Figure 2) ensuring good anchoring. The orifices 10 "and 10 '(FIG. 3) respectively constitute the air inlet and outlet of the regulator and are respectively connected to the fan 3 and the sleeve 4 (FIG. 1) while the orifices 13" (FIGS. 3 and 4). and 13 '(FIGS. 2 and 4) respectively form the gas inlet and outlet of the regulator and are respectively connected at 20 "and 20' to the pipes 5 and 6 (FIG. 1), the chambers 12" and 12 'separated by the element 14 serving respectively arrival and fate chambers ie, an air circuit, ", 11", 11 ', 10' (FIG. 3) and a gas circuit 13 ", 12", 15, 12 'and

13 '(Figure 4).

  It is clear that the plate 18 and the pin 19 form shutters for respectively 11 ', 11 "and 15 passage lights respectively of air and gas Depending on the sliding of the slide 9, said lights 11', 11" and 15 are more or less open. For example, in FIG. 2, a free section 21 of air passage and a free section 22 of

gas passage.

  If the slot 15 has a constant section over its entire length, it can be seen in Figure 2 that the slots 11 'and 11 "here have a substantially trapezoidal section so that the flow of the slide 9 varies the ratio of the sections of passage of air and gas and thus the ratio of the feed rates (at presumed substantially constant pressure) .The purpose of the regulator is indeed to allow a flow ratio between the two fluids substantially constant at the outlet of the burner, while varying the flow rate of the mixture (air flow curves and gas output at the burner output substantially parallel), which generally implies, as already mentioned above, a ratio of variable feed rates according to the resistance

  aeraulic said burner and characteristics of the fan 3.

  The shape of the lumens 11 ', 11 "and 15 is generally determined by successive experiments, seeking to obtain a CO2 level at the outlet of the burner, which is substantially constant, which corresponds to a stoichiometric combustion (one of the lights, here the light 15 may, as in the example described but not required, be of constant section over at least a portion of its length, the other or the others especially being

then defined by experiences).

  The displacement of the slide 9, which is thus intended to vary the power of the burner, is for example obtained by means of a small motor with two directions of rotation which drives in rotation a fixed longitudinal position threaded rod which is screwed or unscrewed. in a tapped joint of a crank pin 24 (Figures 2 and 3) arranged in the plate 18, while a hole 25 is provided for the passage of said screw, so that the drawer can

slide in both directions.

  The driving motor is for example a stepping or continuous motor, controlled by an electronic control system or an aquastat adapted according to the use of the burner which can equip including a water boiler or an air generator

hot.

  If the modulator just described adapts to many types of burners, the invention recommends the burner shown in Figure 1. It is indeed clear from what precedes a modulator according to the invention is a function of the burner to equip (shape lights) or vice versa, especially if one

wants to optimize the results.

  The burner 1 of FIG. 1 has, as already mentioned, an air inlet sleeve 4 which opens substantially tangentially in an outer circular envelope 26 provided with a base 27 comprising secondary air orifices 28 and passage ports for an ignition electrode 29 and an ionisation flame control electrode 30, both

  held by lugs 46,46 ', adjusting screw.

  In the center of the base 27 is arranged a grid of

  combustion 31 provided with openings 32 for flame passage.

  The combustion grid 31 is extended inwards by a cylindrical wall 33, headed by a disc 34, these two

  elements forming a mixing chamber 39.

  The disk 34 has a central orifice 35 extended towards the inside of the mixing chamber by a sleeve 36, while a tube 37, connected to the gas supply pipe 6 to the burner, passes through the orifice 35 to finish on the base, in the vicinity of which it is provided with calibrated orifices 38 of

gas passage.

  A cylindrical wall 40 integral with the casing 26, forms a deflector which delimits an annular zone 41, while the chamber 39 comprises a cylindrical deflector 42 which delimits an inner annular zone 43, itself provided with deflectors

44 and 45.

  The air thus arrives tangentially through the sleeve 4 in the annular zone 41 where it expands by spreading evenly during its circular movement, a portion of the air (secondary air) exiting through the orifices 28. arranged around the combustion grate 31, while the other part of the air (primary air) reaches with a swirling motion in the mixing chamber 39 passing through

  the orifice 35 and bypassing the sleeve 36.

  The gas that arrives through the orifices 38 of the tube 37 mixes with the primary air and the mixture thus arrives in the annular zone 43, bypassing the deflector 42, then up to the combustion grate 31 after having zigzagged between the deflectors

44.45.

  The arrangement of the elements allows movements of air and airgaz mixture, whirling with winding paths through the baffles formed by the various deflectors 40,42,44,45 and the sleeve 36, so that one obtains, at the the vicinity of the orifices 32 of the combustion grate, an intimate mixture fuel-oxidant, distributed uniformly over 360 degrees,

thus ensuring a regular flow.

  The quality of the air-gas mixture and of its flow rate is obviously important to allow an interesting modulation of power without there being a return or detachment of

  flame on one side or the other of the combustion grate 31.

  The modulation range will of course depend on the dimensions of the elements, the number and the sections of the orifices

  respectively 28 of secondary air and 32 of passage of flame ...

  It is also clear that the burner which has just been described can be used without regulator and have a

operation in all or nothing.

  As can be seen in the description which

  precedes, the regulator according to the invention is simple, inexpensive and foolproof. It also makes it possible to achieve very low flow rates

  low for both air and gas.

  Finally, it is obviously possible to realize the various elements in the most diverse materials such as aluminum,

  plastic, composite materials ...

Claims (8)

  1) Power regulator for gas burner, characterized in that it has two separate circuits for respectively air and gas, each circuit having an inlet port (10 ", 13") and an outlet port (10 ', 13') communicating with each other via at least one lumen (11 ', 11 "and 15), the inlet ports being intended to be connected to fluid supply means (3.5) respectively air and gas and the outlet openings being intended to be connected to the burner (1), while the lights can be more or less closed each depending on the displacement of a shutter (18,19) arranged   movably in the regulator.   2) A regulator according to claim 1, characterized in that the shutters (18,19) of the two air and gas circuits are interconnected mechanically to form a single slide (9) whose displacement ensures the simultaneous movement of both shutters.   3) Regulator according to one of claims 1 and 2,   characterized in that at least one (15) of the lights has, on at least a part of its length, parallel sides so as to clear a passage section during the displacement of the shutter on this part which is directly proportional to said displacement.   4) Regulator according to one of claims 2 and 3,   characterized in that the slide (9) is movably mounted in translation and movable by a control and adjustment means step by step or continuously.   Regulator according to one of Claims 2 to 4,   characterized in that it has two identical air passage apertures (11 ", 11 '), coaxial with each other and with the air inlet (10") and outlet (10') ports, and two respective gas supply (12 ") and outlet (12 ') chambers, each of which communicates with the inlet (13") and outlet (13') gas ports, respectively, while said inlet and outlet chambers the gas outlet are separated from each other in a sealed manner by a light carrier (14) for the gas and that the slide (9) is slidably mounted in such a way that the air (18) and gas (19) shutters slide. respectively   between the air lights and in front of the gas light.   6) Regulator according to claim 5, characterized in that it is formed by two shells (2 ", 2 ') assembled together and each provided with one of the lights (11", 11') of air and its corresponding inlet (10 ") or outlet (10 ') air outlet and one of the respective inlet (12") or outlet (12') chambers of gas and its corresponding inlet orifice (13 ") or outlet (13 ') of gas while the light-carrying member (14) for the gas and the sliding drawer (9) are arranged between the shells in a groove (8", 8') provided in this effect in each shells.   7) Regulator according to one of claims 5 and 6,   characterized in that the light carrier member (14) for the gas has a shape adapted to the shape of the gas inlet and outlet chambers (12 ", 12 ') which it separates in a sealed manner, and that said element is provided with a slot (15), passing right through its central part, and a bore (16) of a diameter at least equal to the width of the slot and which is arranged in its thickness for communicate with said slot while the gas shutter is formed by a pin (19) of a shape corresponding to said bore (16) in which it slides to close more or less said slot and that the air shutter is   formed by a plate (18) integral with said pin (19).   8) Regulator according to one of claims 5 to 7,   characterized in that the gas inlet and outlet openings (13 ", 13 ') are arranged along parallel axes which are perpendicular to the common axis of the air slots (11", 11') and   orifices (10 ", 10 ') for entering and exhausting air.   9) Combined gas burner with regulator according to one   Claims 1 to 8 and having an air inlet (4)   communicating with a mixing chamber (39) in which a gas inlet (37) opens centrally and under which is arranged a combustion grate (32), characterized in that the outlet orifices (10 ', 13') respectively The air and gas from the regulator are connected to the inlets (4,37) of air and burner gas, respectively, while at least one annular deflector (40) is arranged in the burner air circuit before the burner. arrival thereof in the mixing chamber (39) and at least one annular deflector (42) is arranged in the mixing chamber, to form baffles in the paths   traveled respectively by the air and the air-gas mixture.