MXPA99007752A - Water heater with sensitive air inlet to the ac - Google Patents

Abstract

The present invention relates to a water heater characterized in that it comprises: a water container, a combustion chamber adjacent to the container, said combustion chamber having at least one inlet formed at least partially of a heat sensitive material to admit air and strange emanations into the combustion chamber, said at least one entry being able to allow the air and foreign emanations to enter the combustion chamber to be burned and, upon the start of combustion, capable of deforming in response to the elevated temperatures and further limit the entry of air and strange fumes in said combustion chamber, and a burner associated with the combustion chamber and arranged to burn fuel to heat the water inside the container.

Description

WATER HEATER WITH AIR INTAKE SENSITIVE TO HEAT (and FIELD OF THE INVENTION The present invention relates to air inlets for water heaters particularly to improvements to gas-fired water heaters adapted to make them safer to use. The most commonly used gas-fired water heater is the storage • type, generally comprising an assembly of a storage tank. water, a main burner to provide heat to the tank, a pilot burner < permanent to start the main burner on demand, an air inlet adjacent to the burner near the base of the cover, an exhaust duct and a cover to cover these components. Another type of gas-fired water heater is the instantaneous type, which has a water flow path through a Heat exchanger heated again by a main burner started from a flame of the pilot burner. For convenience, the following description is in terms of storage type water heaters but the present invention is not limited to this type. In this way, reference to "water container", "water containment and means of flow, means for storing or containing water "and similar these terms include tanks, tanks, sacks, water bags and the like within water heaters supplied with storage type gas and water flow paths such as pipes, pipes, ducts, heat exchangers and the like within instant-type gas-fired water heaters 25 A particular difficulty with many locations for water heaters is that the locations are also used for the storage of other equipment such as a blinding of grass, snowblowers, snow blowers and the like It is a common procedure for such machinery to be replenished at these locations There have been a number of reported cases of spilled gasoline and associated strange fumes that are accidentally ignited. Ignition available, such as refrigerators, running engines, motors s electrical, electric and gas dryers, electric light switches and the like. However, gas water heaters have sometimes been suspect because they often have a pilot flame. Vapors from flammable liquids or gaseous substances spilled or escaping into a space in which an ignition source is present, provides a potential for ignition. "Strange emanations", "strange emanation species", "emanations" or "strange gases" are sometimes used to cover gases, vapors or fumes generated by a wide variety of volatile or semi-volatile liquid substances. such as gasoline, kerosene, turpentine, alcohols, insect repellent, weed killers, solvents and the like, as well as non-liquid substances such as propane, methane, butane and the like. Many of the internally related factors influence whether a particular fuel spill leads to ignition. These factors include, among other things, the quantity, nature and physical properties of the particular type of fuel spilled. Also influential is whether the air currents in the room, whether natural or artificially created, are sufficient to accelerate the spread of the emanations, both laterally and in height from the point of the devane to a point of ignition still not so strong as to ventilate these emanations without damage, that is, such that the intervals of the air to fuel ratio are able to allow ignition, are not achieved given all the circumstances that surround them.

A circumstance surrounding it is the relative density of the emanations. When a spilled liquid fuel spreads on a floor, normal evaporation occurs and the liquid emanations form a mixture with the surrounding air that can in some times and in some locations, be within the range that will ignite. For example, the range for common gasoline vapor is between about 2% and 8% gasoline with air, for butane between 1% and 10%. These mixtures form and spread through a combination of processes that include natural diffusion, forced convection due to the draft of the air stream and by the displacement of the gravitationally affected molecules upwards of a less dense gas or vapor by those of another more dense The most common fuels stored in houses are, as it is used either gases with densities relatively close to that of the air (for example, propane and butane), or liquids that form emanations that have a density close to that of the air (for example , gasoline, which can contain butane and pentane among other components that is very typical of this liquid fuel). -In the reconstructions of accidental ignition situations, and when gas water heaters are sometimes suspected, and which involve spilled fuels typically used around houses, it is reported that the spill is sometimes at ground level. , it was reasoned that it spreads outwardly from the spill at the beginning just at floor level. If appreciable forced mixing, the air / fuel mixture would tend to be at its very flammable levels just at ground level for a longer period before it slowly diffused towards the ceiling of the space of the room. The main reason for this observation is that the density of the emanations typically involved is not very different from that of the air. Combined with the tendency of concentrations capable of igniting from fumes that are at or near ground level, it is the fact that many gas appliances often have their sources of ignition at or near that level. The invention helps to substantially raise the probability of the successful confinement of the flammable substances spilled from spill situations into the combustion chamber.

BRIEF DESCRIPTION OF THE INVENTION The invention relates to a water heater that includes a water container and a combustion chamber adjacent to the container. The combustion chamber has at least one inlet to admit air and foreign fumes into the combustion chamber. The inlet is formed from a heat-sensitive material and having a plurality of openings or ports. The inlet is capable of allowing the air and the foreign fumes to enter the combustion chamber and prevents the ignition of the foreign emanations out of the combustion chamber. The water heater also includes a burner associated with the combustion chamber and arranged to consume the fuel to heat the water within the container.

. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic, partial cross-sectional view of a gas-fired water heater having a simple air inlet in accordance with aspects of the invention; Figure 2 is a cross-sectional view of the water heater taken through line ll-ll of Figure 1.

Figure 3 is a schematic plan view showing a part of the base of a combustion chamber of a water heater including an air inlet. Figure 4 is an enlarged schematic plan view of an air inlet shown in Figure 2 with the burner and the fuel supplying apparatus removed for ease of understanding. Figure 5 is a cross-sectional view taken through line A-A of Figure 4. Figure 6 shows a top plan view of a preferred air inlet of the invention. Figure 7 illustrates a plan view of a single opening taken from the air inlet shown in Figure 6. Figure 8 is a detailed plan view of the separation of the part of the arrangement of the openings or slides on the plate of the inlet of Figure 6. Figure 9 shows two adjacent openings, taken from the air inlet of the type shown in Figure 6, the opening on the left representing the state of the art to expose the heat caused by the vapors consumed and the opening on the right representing a state after exposure to heat caused by the vapors consumed. Figure 10 is a plan view of a main burner, a pilot burner, the thermocouple and a thermocouple arrangement and of the air inlet in a combustion chamber of a particularly preferred embodiment of the invention. Figure 11 is a side view of the structure illustrated in Figure 10 rotated 90 °. Figure 12 is an exploded view of the main burner arrangement of the pilot burner and the thermocouple shown in Figure 10.

Figure 13 is a side view of the structure illustrated in Figure 12 rotated 90 °.

DETAILED DESCRIPTION OF THE INVENTION Conventional water heaters typically have their sources of ignition at or near ground level. In the course of the attempt to develop combustion chambers of apparatuses capable of confining the flame within the apparatuses, it has been discovered that a type of air intake constructed by forming holes in a sheet of heat-sensitive material in a particular manner has particular advantages. in resistance to damage when it is located on the bottom of a heavy appliance such as a water heater which is usually standing on the floor. It has also been found that providing well-defined holes in a controlled geometry helps the accuracy of the air intake and confinement functions of the flame in a wide variety of circumstances. A thin heat-sensitive plate having many apertures of carefully specified size formed, formed, cut, punched, perforated, engraved, punched and / or deformed through it at a specific spacing provides an operational balanceexcellent precision and ease of exact manufacturing. In addition, the plate provides resistance to damage before being sold and supplied to a fuel consuming apparatus such as a water heater having such an air intake and during any subsequent installation of the apparatus on a user's premises. In experiments conducted with a number of metallic air intakes it was observed that some variants were more effective than others in the function of confining the flame. Certain variants allowed the flame to consume in close contact with the inner surface of an air inlet plate, thus deriving the substantial elevation of the plate temperature on its outer surface by heat conduction. In some cases, this is observed to involve turbulent combustion oscillations which further heated the inlet plate. It has been found that an excessively high temperature of the perforated plate can possibly be transferred by conduction through the relatively thin metal plate to the point where it can reach a sufficiently high temperature (in the order of 120 ° F or 675 ° C) , such that a failure could possibly occur under some conditions caused by the ignition of the hot surface of the emanations spilled on the outside of the combustion chamber. During the experimentation which was designed to create potential ignition conditions that would not likely occur under normal operating conditions and, with a video camera film inside the combustion chamber, it was discovered that a potential failure mode occurred in some cases to involve by involve heating particularly in the periphery of the entrance plate at a faster speed than that in the center. Associated with this observation, has been the phenomenon of the periphery of the plate that tends to retain - narrowly the flames formed on the side of the combustion chamber of the air inlet plate, considering towards the center, without taking into account The air-inlet plate is rectangular or circular in shape, there was evidence of a greater tendency for the slats to lift off the surface, more towards the combustion chamber. Where the flames are held tightly in the entrance plate it becomes visibly hotter, which indicates the excess temperature. The invention addresses the ways of satisfying such extreme conditions. The invention is also concerned with ways to avoid detonating wave type ignition that was discovered to propagate from the inside to the outside of the combustion chamber through the entry plate under certain circumstances, reducing the amount of flammable fumes that can enter the combustion chamber before initial ignition occurs inside the combustion chamber; and also, avoiding incidents of prolonged combustion. It will be appreciated that the following description is intended to refer to the specific embodiments of the invention selected by way of illustration in the drawings and is not intended to limit or define the invention different from the appended claims. Turning now the drawings in general and in particular to Figures 1 and 2 there is illustrated a storage type gas water heater 62 which includes a cover 64 surrounding a water tank 66 and a main burner 74 in an enclosed chamber 75. The water tank 66 is preferably capable of retaining the heated water at higher pressures and which is preferably isolated by the isolation of foam 68. Alternative insulation may include fiberglass or other types of fibrous insulation and the like. The fiberglass insulation surrounds the chamber 75 in the lower part of the tank 66. It is possible that the heat-resistant foam insulation can be used if desired. A foam barrier 67 separates the foam insulation 68 and the fiberglass insulation. Located under the water tank 66 is a pilot burner 73 and a main burner 74 preferably using natural gas as its fuel or other gases such as LP gas, other suitable fuels can be substituted. The burners 73 and 74 consume the mixed gas with the area and the resulting hot combustion products rise through the gas outlet conduit 70, possibly with heated air. The water tank 66 is lined with a vitreous coating for resistance to corrosion. The thickness of the coating on the surface of the water tank 66 is approximately one-half inch in thickness from the surface facing inward to avoid "flaking". Also the lower part of the duct 70 is coated to prevent the incrustation that can accumulate in the chamber 75 and possibly partially block the air inlet plate 90. The combustible gas is supplied to both burners (73,74), through a gas valve 69. The gas outlet conduit 70 in this case contains a series of baffles 72 for better transferring the heat generated by the main burner 74 to the water within the tank 66. Near the pilot burner 73 is a gas detection thermocouple. Flame 80 which is a known safe means to ensure that in the absence of a flame in the pilot burner 73 the gas control valve 69 interrupts the gas supply. The water temperature sensor 67, preferably located inside the tank 66, also cooperates with the gas control valve 69 to supply the gas to the main burner 64 on demand. The combustion products pass up and out of the upper part of the cover 64 through the outlet of the duct 66 after the heat has been transferred from the combustion products. The outlet 76 of the duct is exhaust gases conventionally discharged in a draft diverter 77 which in turn is connected to an exhaust duct 78 leading to the outside. The water heater 62 is preferably mounted on the legs 84 to raise the base 86 of the combustion chamber 75 away from the filter. At the base 86 is an opening 87 which is hermetically sealed to the gas by the inlet plate 90, which admits air for the combustion of the fuel gas consumed through the main burner 74 and the pilot burner 73, without considering the relative proportions of the gas. primary and secondary combustion air used by each burner. The air inlet plate 90 is preferably made of a perforated thin sheet of the material that senses the heat such as plastic. Where the base 86 abuts the vertical walls of the combustion chamber 79, the joint surface can be either one piece or alternatively sealed to prevent the ingress of flammable extraneous air or fumes. The gas, water, electricity, control or other connections, fittings, or pipes wherever these pass through the wall of the combustion chamber 79, are sealed. The combustion chamber 75 is air / gas tight except for the means which supply the combustion air and for the exhaust of the combustion products through the conduit 70. The establishment of the pilot flame can be achieved by means of a piezoelectric igniter. A pilot observation window can be provided which is sealed. Cold water is introduced to a lower level of tank 66 and removed from the elevated level in any way as is well known. During normal operation, the water heater 62 operates in substantially the same manner as conventional water heaters except that the air for combustion enters through the air inlet plate 90. However, if the fuel or other fluid flammable spilled is near the water heater 62, then some strange emanations from the spilled substance can be drawn through the plate 90 by virtue of the natural draft characteristic of these water heaters. The air inlet 90 allows the combustible extraneous air to enter, but confines the potential ignition and combustion inside the combustion chamber 75. The spilled substance schemed within the combustion chamber 75 and discharged through the conduit 70 via the outlet 76 and the duct 78. Because the flame is confined by the air inlet plate 90 within the combustion chamber the flammable substance or substances external to the water heater 62 will not be ignited. The air inlet has mounted on or adjacent to its surface facing upward a thermally sensitive fuse in series with an electrical circuit with the pilot flame testing the thermocouple 80 and a solinoid coil on the gas valve 69. With reference to Figure 1, the size of the air inlet plate 90 depends on the requirement of air consumption for the appropriate combustion that meets the assigned specifications to ensure the consumption of the low-polluting gas fuel. Merely by way of general indication, the air inlet plate of Figure 1 should conveniently be about 40 square inches of perforated area when it is adapted to a water heater that has a power consumption capacity of about 2,380 calories per second (approximate) that satisfy the ANSI requirements for the combustion of overload. Figure 3 schematically shows an air inlet to a sealed combustion chamber comprising a wall 87 in the lower wall 86 of the combustion chamber and a heat sensitive material or air inlet plastic plate 90 having a perforated area 100 and a non-perforated edge or flange 101. The holes in the perforated area 100 of the plate 90 can be circular or otherwise, although the slotted holes have certain advantages as will be explained, the following description referring to the slots. Figures 4 and 5 show a preferred arrangement of the air inlet "90 with respect to the lower wall 86 of the combustion chamber.The air inlet 90 is intended to be substantially sealed against the lower wall 86 to prevent the air and / or the foreign fumes pass between the front surfaces of the inlet 90 and the lower wall 86. The inlet 90 has an outer flange 101 that extends beyond the edge of the opening in the bottom wall 86. The flange 101 can be fixed to a corresponding part of the lower wall 86 by various methods such as forming, press fit or fasteners Other means of securing or fixing the air inlet 90 to the wall inlet 86 such as by resistive adhesive are possible. to heat and the like.

The air inlet 90 also most preferably has a raised portion 204 that extends above the upper surface of the lower wall 86. This helps to ensure that the condensation generated in the pipe of the gas outlet conduit 70 is not located or congregate over the air inlet 90 to occlude the openings / slots there. Figure 6 shows an air inlet 90 as will be described to admit air to the combustion chamber 75. The air inlet 90 is most preferably a plastic plate having many small slots 104 passing therethrough. The air inlet should have a thickness of at least about 0.18 pugadas or more. Depending on the plastic and its mechanical properties, the thickness can be adjusted. The parts of the air inlet 90 away from the openings 104 need not be formed from the heat sensitive material since these parts do not need to deform in response to the elevated temperatures. Figure 6 is a plan view of an air inlet plate having a series of openings in the form of slots 104 aligned in rows. All these grooves 104 have their longitudinal axes parallel except for the grooves of the edge 107 at right angles to those of the openings 104 in the remaining perforated area 105. The openings are arranged in a rectangular pattern formed by aligned rows. As mentioned above, the plate is most preferably at least 0.18 inches thick. This provides the air inlet 90 with adequate damage resistance, and in other aspects it operates effectively. The total cross-sectional area of the grooves 104 is selected on the basis of the air flow rate that is required to pass through the air inlet 90 during normal and overburning. The slots 104 are provided to allow sufficient combustion air through the air inlet 90 and there is no exact restriction on the number of total slots 104 or the total area of the air inlet, both of which are determined by the capacity of a gas (or fuel) burner, chosen to generate the heat by combustion of a suitable amount of gas with the amount of air required to ensure complete combustion within the combustion chamber and the size and spacing of the grooves 104 The air for combustion passes through the slots and not through any passage or larger inlet air passages into the combustion chamber. This major entry is not provided. The water heater of the invention thus includes a water container and a combustion chamber adjacent to the container. The combustion chamber has at least one heat-sensitive inlet to admit air and foreign emanation species into the combustion chamber. The inlet has a plurality of openings, each opening having a limiting dimension sufficient to confine the ignition and combustion of the foreign emanations within the combustion chamber. The water heater also includes a cremator associated with the combustion chamber and arranged to burn the fuel to heat the water within the container. Figure 7 shows a single slot 104 having a length L a width Fluid and curved ends. To confine any incident of the aforesaid accidental ignition within the combustion chamber 75, the slots 104 must be formed to have at least about twice the length L according to the width W, and are preferably at least about 12 times long. Long to wide (L / W) ratios outside these limits are also effective. The slots are more effective in controlling accidental deflagration or detonation ignition than circular holes, although the beneficial effect can be observed with ratios of L? V in the grooves as low as about 3. The higher L? / V ratios of about 15, there may be a disadvantage in that it may be possible in a thin flexible film air inlet 90 the possible distortion of one or more grooves 104 as it would tend to allow opening in the center of the slots creating a loss of control of the width W dimension. However, if the temperature can be controlled at distortion then larger slots may be useful; the reinforcement of a thin entry plate by a hardening manner such as with transverse breaking, can assist in the adoption of higher L? / V ratios, the L? / V ratios greater than about 15 are otherwise useful for Maximize air flow rates. A particularly preferred length L is approximately 6mm and a particularly preferred W is 0.5mm. In order to perform its ignition confinement function it is important that the slots 104 operate with respect to any of the extraneous flammable species of fumes, which can reasonably be expected to be involved in a possible spillage external to the combustion chamber 75 of the which the air inlet of the invention forms an integral part or an accessory. Figure 8 shows the separation dimensions of the groove and between the openings adopted in the embodiment shown in Figure 6. The dimensions of the openings are preferably the same as in Figure 7 and have a length L of 6mm and a width W of 0.5. the ends of each groove are semicircular but grooves with ends are more square. The chosen manufacturing process can influence the actual shape seen in the groove. Stitching these large hole numbers can be difficult with respect to keeping such small punches if the radii of the corners are not well rounded. The process of photochemical machining of the air inlets 90 with slots 104 is also more adapted to maintain the grooves with rounded corners.

The separation between openings illustrated in Figure 8 performs the required confinement function in the previously described situation. The dimensions are preferably as follows: A of approximately 2.0 mm and B of approximately 2.0 mm. Figure 9 shows a Figure 104 in two states, a state shown on the left that is an opening before exposure to heat caused by the vapors or fumes consumed and the drawing on the right showing an opening representing a post-exposure state of heat caused by vapors or fumes consumed. The change in size and shape of the opening 104 as shown in Figure 9 is achieved as a result of the ignition of the foreign emanations that have passed through the air inlet 90 and ignited on the air inlet surface 90. facing the combustion chamber 75. The presence of the flames on or near the surface of the air inlet 90 causes its temperature to increase, thereby causing the heat-sensitive material forming the air inlet to increase and in point particular that begins to soften and approximate and reach its melting temperature at which point the walls or edges of the openings 104 begin to change shape and the openings contract as the plate material flows and fills in the opening. The result in the decrease in the total open space of the air inlet is the decrease in the entry of air and strange emanations in the combustion chamber, thus reducing combustion and, giving sufficient time suffocating the combustion all simultaneously. Of course, there is a multiplicity of openings 104 in the air inlet 90. Some of the openings 104 may be made to close completely while leaving another slightly open, but not sufficiently to allow continuous combustion within the combustion chamber. .

Suitable materials for forming the plastic or heat-sensitive air inlet 90 should most preferably possess crystalline characteristics such that the heat sensitive material or plastic will flow or partially flow when heated. In addition, the material has heat deflection temperature in excess of about 400 ° F and melting points in excess of about 500 ° F. Arnaco AMODEL polymers, a grade of polyphthalamide resin (PPA) or Phillips 66 RAYTON, reinforced with glass fiber, a polyphenylene sulfide compound (PPS) filled with glass fiber are especially preferred examples of materials suitable for plastic air inlets. Of course, other materials having the proper heat sensitivity, processability, strength and durability can be used. Referring to Figures 10 to 13, these collectively show the fuel supply line 210 and the fuel line of the pilot 470 extending outwardly from a plate 250. The plate 250 is capable of removably sealing a jacket 600 that It forms the side wall of the combustion chamber 75. The plate 250 is held in position by a pair of screws 620 or by any other suitable means. The pilot fuel line 470 and the fuel supply line 210 pass through the plate 250 in a substantially fixed and sealed condition. The liner or cover 520 also extends through the plate 250 in a substantially fixed and sealed condition as does the line of the lighter 640. The line of the lighter 640 is connected at one end to a button of the lighter 220 and to a piezo igniter 660 by its other end. The cigarette lighter button can be obtained from Channel Products, for example. Each of the pilot fuel supply line 470, the pilot fuel supply line 470, the fuel supply line 210 and the liner or cover 520 are capable of being removably connected to the gas control valve 69 by means of compression nuts. Each of the compression nuts is threaded and threadedly attached to the control valve 69. The liner or cover 520, preferably made of copper contains wires (not shown), of the thermocouple 80 to ensure that in the absence of a flame in the pilot burner 73, the gas control valve 69 interrupts the gas supply. The thermocouple 80 can be selected from those known in the art. The Robershaw Model No. SANITARY TOWEL 750U is preferred. The ratio of the pilot burner to the air inlet is very important in the auxiliary or pilot operation mode only. The cap or hood of the pilot burner 73 should be located over the openings 104. This creates conditions for the soft ignition of the flammable vapors as they flow through the openings. A pilot located far from the openings can result in at least two undesirable conditions: the sudden ignition of the vapors and delay in the ignition of the vapors which can result in a small deflagration inside the combustion chamber 75. This deflagration can produce possibly a pressure wave that can push the flames through the openings 104 and ignite any of the vapors that remain outside the water heater. The location of the thermocouple 80 is important. The rapid stoppage of the gas valve 69 is desirable for several reasons. The deactivation of the gas valve 69 results in the depletion of the pilot burner 73 and the subsequent shutdown of the main burner 74. Therefore, the main burner 74 can not be ignited which can result in the development of undesirable pressure waves within of the combustion chamber 15 while the flammable vapors are being consumed in the air inlet plate. Spills of flammable vapor can result in vapor concentrations that measure inward and leave the flammable range. The vapors adjacent to the air inlet 90 may ignite and be consumed for a short period of time before the openings 104 have an opportunity to reduce in size or close to the foreign emanations in order to self-extinguish. Disabling of the gas valve 69 (ie, the pilot burner torque 73) and of the main burner 74) removes the water heater as an ignition source in the event that the vapors must again reach a flammable concentration level. . It should be understood that the invention disclosed and defined herein extends all alternate combinations of two or more of the individual features mentioned or apparent from the text or the drawings. All of these different combinations constitute several alternate aspects of the invention. The foregoing describes the embodiments of the present invention and the modifications, obvious to those skilled in the art that can be made to them, without departing from the scope of the present invention.

Claims (28)

1. - A water heater comprising: a water container; a combustion chamber adjacent to the container, said combustion chamber having at least one inlet formed at least partially from a heat-sensitive material to admit air and foreign emanations into the combustion chamber; said at least one entry making it capable of allowing air and extraneous emanations to enter the combustion chamber to be burned and, upon initiation of combustion capable of deforming in response to elevated temperatures and further limiting the inlet of air and strange fumes in said combustion chamber; and a burner associated with the combustion chamber and arranged to burn fuel to heat the water within the container.

2. The water heater according to claim 1, wherein said heat-sensitive material is a plastic.

3. The water heater according to claim 2, wherein the plastic is selected from the group consisting of polyphenylene sulfide resin and polyphthalamide resin.

4. The water heater according to claim 1, wherein at least one inlet has a plurality of openings that are capable of shrinking when exposed at elevated temperatures.

5. The water heater according to claim 1, wherein the heat sensitive material has a heat deflection temperature of about 400 ° F or more.

6. - The water heater according to claim 1, wherein said at least one inlet has a plurality of openings, at least one of which is adjacent to the pilot burner associated with the combustion chamber to ignite the strange emanations as that they pass into the combustion chamber and before there is an accumulation of potentially explosive fumes inside the combustion chamber.

7. The water heater according to claim 4, wherein the openings comprise grooves.

8. The water heater according to claim 1, wherein the heat-sensitive material has a melting point of about 500 ° F more.

9. The water heater according to claim 2, wherein the plastic contains glass fibers.

10. The water heater according to claim 1, wherein the openings are arranged in rows.

11. The water heater according to claim 1, wherein the openings are grooves exposed in rows in at least one inlet with at least one peripheral row in said at least one inlet comprising the grooves arranged parallel to each other. and having their longitudinal axes at an axis of approximately 90 ° to the orientation of each of the longitudinal axes of the grooves in the other rows.

12. The water heater according to claim 1, wherein said at least one inlet is constructed from a sheet of said heat sensitive material and said openings are elongated and separated apart therethrough, being the openings arranged in such a way that there are at least two regions of openings, an internal region that is composed of a group of said openings, and an outer region that is composed of the rest of the openings, said outer region having a separation between openings between the adjacent openings which is greater than the spacing between openings in the first internal region.

13. The water heater according to claim 1, wherein the water heater further comprises a separate outlet from at least one inlet allowing the combustion products to leave the combustion chamber.

14. The water heater according to claim 1, wherein each of said at least one inlet of openings.

15. A water heater comprising: a water container; a combustion chamber adjacent to the container; a burner associated with the combustion chamber and arranged to burn the fuel to heat the water within the container; and at least one plastic inlet having a plurality of holes associated with the combustion chamber adapted to admit air and foreign fumes into the combustion chamber and prevent the ignition of the remaining foreign emanations out of the combustion chamber, said holes in the plastic inlet being able to deform upon the occurrence of exposure to high temperatures and decrease the entry of additional amounts of air and foreign fumes into the combustion chamber.

16. A water heater comprising: a water container; a combustion chamber adjacent to the container; a burner associated with the combustion chamber and arranged to burn the fuel to heat water inside the container; and at least one heat-sensitive inlet having a plurality of associated orifices such as the combustion chamber, adapted to admit air and foreign emanations into the combustion chamber and prevent ignition of the foreign emanations outside the combustion chamber; said openings being able to shrink in size upon exposure to high temperatures, thus also limiting the entry of air and strange fumes into said combustion chamber.

17. An air inlet for a combustion chamber of the water heater that is subjected to exposure to foreign fumes comprising a plate at least partially formed of a heat-sensitive material to admit air and foreign fumes into the chamber. combustion, said plate being able to allow the entry of air and strange emanations into the combustion chamber to be burned and, upon initiation of combustion, able to deform in response to high temperatures and also limit the entry of air and fumes strange to the combustion chamber;

18. The air inlet according to claim 17, wherein the heat-sensitive material is a plastic.

19. The air inlet according to claim 18, wherein said plastic is selected from the group consisting of polyphenylene sulfide resin and polyphthalamide resin.

20. The air inlet according to claim 17, wherein the plate has a plurality of openings that are capable of shrinking when exposed to elevated temperatures.

21. The air inlet according to claim 17, wherein said heat sensitive material has a heat deflection temperature of about 400 ° F or more.

22. - The air inlet according to claim 17, wherein the plate has a plurality of openings, at least of which is adjacent to a pilot burner associated with the combustion chamber to ignite the foreign emanations as they pass to the combustion chamber and before there is a potentially explosive accumulation of fumes inside said combustion chamber.

23. The air inlet according to claim 20, wherein the openings comprise grooves.

24. The air inlet according to claim 17, wherein said heat-sensitive material has a melting point of about 500 ° F or more.

25. The air inlet according to claim 18, wherein said plastic contains glass fibers.

26. The air inlet according to claim 17, wherein said openings are arranged in rows. 27.- An air inlet for a combustion chamber of the heater of the water heater that is exposed to the exposure of foreign emanations, comprising a plastic plate having a plurality of holes adapted to admit air and strange emanations towards the chamber of combustion and avoid ignition of the remaining foreign emanations outside the combustion chamber, said holes in the plastic entrance being able to deform when exposed to high temperatures and decrease the entry of additional amounts of air and strange emanations into the combustion chamber . 28.- An air inlet for a combustion chamber of the water heater that is subjected to the exposure of foreign emanations, comprising a heat-sensitive plate having a plurality of orifices associated with the combustion chamber adapted to admit air and strange emanations towards the combustion chamber and to avoid the ignition of the strange emanations outside the combustion chamber, the orifices being able to shrink in size when exposed to the elevated temperatures, thus limiting also the entry of air and strange emanations into the combustion chamber.