Patent Grant
8454352
This invention generally relates to energy conservation systems, and more particularly to energy conservation systems to be employed with gas burning appliances to reduce the amount of gas used by a pilot while ensuring proper burner and flammable vapor ignition.
It has now been recognized that the world's environment is suffering too much from global warming caused by greenhouse gas exposure in the atmosphere. To address this problem governments are now starting to adopt targets for reducing the emission of greenhouse gases to the environment and play their part to address this problem for future generations. While some countries have not adopted a firm goal, other countries, for example Australia, have adopted a policy for the reducing greenhouse gases by 20% by the year 2020.
Greenhouse gases can be emitted from cars, industry, farming, and households to name a few. While certainly not as apparent as a large factory with tall smokestacks, within a normal household the gas burning appliances, such as furnaces, water heaters, etc., all release such greenhouse gases as a by-product of the combustion process itself. While the appliance industry has taken a leading role in energy efficiency and environmental concern, further improvement is always foremost in mind of the appliance design engineer.
With such further improvement in mind, especially with the increased awareness of global climate change and changing governmental regulations, it is noted that hot water heaters, both internal and externally installed units, can be one of the more fairly inefficient appliances in energy conservation, and therefore require the burning of additional fuel to maintain the set point temperature. This, of course, results in the additional production of greenhouse gas beyond that which a more efficient appliance would produce.
A typical hot water heater includes a vertical tank with a centrally located flue pipe. A gas burner is positioned underneath the tank and is controlled by a combination gas controller valve. The combination gas controller valve incorporates an On/Off valve, a pilot safety circuit, pilot and main burner pressure regulators and their associated supply pipe connections, as well as a thermostat to control the hot water heater to maintain the water in the storage tank at a predetermined temperature.
Upon the thermostat calling for more heat, the main gas valve opens to allow gaseous fuel (gas) to flow to the main burner where it is ignited by the pilot light. Ignition and combustion of the gas results in hot flue gas being generated. The heat from the hot flue gases is transferred to the cold water via the bottom of the tank and through the walls of the central flue pipe. The flue gases exit out the top of the hot water heater.
There are generally two types of hot water heaters used throughout the world classified by their installation location. For an indoor water heater such as used in the North American market, the hot flue gases exit through a draft diverter that is connected to a flue pipe which pipes the flue gases safety to an outside location. Air for combustion of the gas is drawn into the combustion chamber at the bottom of the hot water heater. For an outdoor hot water heater such as used in the Australian market, the flue gases pass safely through a balanced flue terminal at the top of the heater to the outside atmosphere. The balanced flue terminal is so designed to allow a continuous supply of air for combustion irrespective whether the burner is on or off under all types of wind conditions. The air for combustion is transferred to the bottom of the heater internally within the appliance.
For each of these two types of hot water heaters, many manufacturers are offering configurations that are flammable vapor resistant. Flammable vapor resistant hot water heaters normally have a flame trap in the bottom of the combustion chamber as the fresh air inlet. The flame trap is a special design to allow air for normal combustion and also any flammable vapors to enter the combustion chamber. Such flammable vapors may be the result of an accidental gasoline spill, for example. The design is such that any resultant ignition/explosion due to flammable vapors (e.g. gasoline) in the combustion chamber will not escape the appliance and ignite the spill outside the appliance. Such designs have recently been mandated in the United States.
As a result of the two requirements, i.e. ensuring ignition of the main burner upon a call for heat and safely igniting any flammable vapor that enters the air intake, the positioning of the pilot and the size of the pilot flame itself become very important.
Unfortunately, one of the current disadvantages for hot water heaters is the overall service efficiency of the appliances. Service efficiency is defined as the energy delivered to the hot water from the hot water heater each day, divided by the energy burnt in the gas to heat the water and to maintain the hot water in the tank at the desired temperature. The service efficiency may vary from around 0.50 or 50% for poor performing appliances, to appliances just complying to US regulations around 0.59, to superior products from 0.64 or 64% service efficiency. Low service efficiency may be due to poor thermal efficiency of the heat into the water when the burner is on and/or excessive heat losses when the burner is off. Since the main burner is only on for one to two hours per day heating the stored water to keep it ready for use, burning of gas for the pilot for the remaining 22 hours only contributes to the inefficiency issues.
As is clear from the foregoing, there is a need in the art for a pilot control system for a hot water heater that conserves energy and yet still ensures ignition of the main burner and safe ignition of flammable vapor. Embodiments of the present invention provides such a pilot control system. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.
In view of the above, embodiments of the present invention provide a new and improved energy saving pilot for a hot water heater or other gas burning appliance. More particularly, embodiments of the present invention provide a new and improved pilot for a hot water heater or other gas burning appliance that not only saves energy and reduces greenhouse gas emissions, but also ensure ignition of the main burner and safe ignition of flammable vapor.
In one embodiment, the invention utilizes bleed gas from a safety relay valve to increase the size of the pilot flame just prior to opening a main flow of gas to the burner from a micro-pilot flame size to an ignition flame size when the hot water heater's main combination gas controller calls for heat. This allows for a smaller amount of gas to be used for the pilot to operate it as a micro-pilot during the periods when the burner is off with no call for heat and will ensure ignition of the main gas flow to the burner when a call for heat has been issued. The smaller or micro-pilot flame will also provide smoother ignition of gasoline fumes in Flammable Vapor Resistant heaters.
In another embodiment, the invention utilizes a physically separate micro-pilot and a booster or ignition pilot that is operated from bleed gas from a safety relay valve. The bypass gas flow to the booster pilot will occur just prior to opening the main flow of gas to the burner. The micro-pilot flame will ignite the booster pilot supplied with the bypass gas, which will then ignite the main gas flow to the burner. This allows for a smaller amount of gas to be used for the pilot to operate it as a micro-pilot during the periods when the burner is not on and will ensure ignition of the main gas flow to the burner when a call for heat has been issued. The smaller or micro-pilot flame will also provide smoother ignition of gasoline fumes in Flammable Vapor Resistant heaters.
In each embodiment, the micro-pilot is sized to be large enough to provide enough heat to the safety thermocouple to keep the gas pilot safety valve open in a typical hot water heater or other gas burning appliance combination gas controller. It is also sized to be large enough to resist air turbulence due to ignition and combustion of the natural gas from the main burner. Embodiments of the present invention are also positioned so that smooth ignition results to the main burner and to any flammable vapor. Rough ignition of flammable vapor will normally result in a small explosion in the combustion chamber forcing the flame front through the flame trap, possibly igniting the gasoline outside the water heater which could result in a larger explosion and a household fire. Embodiments of the present invention position the pilot flame for ignition relatively closer to the burner for low NOx burners to obtain smooth ignition.
Using bleed gas to boost the pilot size or to supply a booster pilot just prior to ignition of the main burner in accordance with embodiments of the present invention gives improved performance on ignition and saves gas. It allows the potential to reduce the normal size of the pilot size by way of example only approximately 50% thus saving around 4.8 Mj/day (4500 Btu/day) energy.
Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Turning now to the drawings, there is illustrated in
Returning specifically to
In the illustrated hot water heater and as described more fully in the above referenced pending application, standby heat loss is substantially reduced by the inclusion of a damper actuator valve 114 that is located at the top of the hot water heater 100. A damper flapper valve crank shaft rod 116 driven by the damper actuator valve 114 is connected to a damper flapper valve 118 located on the flue pipe 110. This damper flapper valve 118 is used to close off the flue pipe 110 when the burner is off. The shape of the damper flapper valve 118 is normally round to close off the typical round flue pipe 110, although it would be square to close off square ducting, etc.
As may be seen in
As discussed above, markets outside of North America, such as in Australia, install their hot water heaters outside of the dwellings. An embodiment of one such outdoor hot water heater 136 is illustrated in
The damper actuator valve 114 is located inside the terminal 140, attached to the outside of the transfer duct, which is adjacent to the heater flue pipe as it exits into the transfer duct (show in this illustration as 110 for ease of understanding). In this embodiment the damper actuator valve 114 is located close to the cylinder flue pipe 110 outlet in order to reduce standing losses. It should also be located either outside the terminal 140 away from the fresh air inlet or alternately be positioned in the terminal 140 but located so as not to create any turbulence under windy condition, e.g. in a static wind pocket within the terminal 140.
The damper flapper valve 118 to closed off the flue pipe 110 is located immediately over the outlet of the flue pipe 110 inside the transfer duct and is in communication with the damper actuator valve 114 via the damper flapper valve crank shaft rod 116. Small bore piping 120, 128 is used to connect the safety relay valve 122 to the damper actuator valve 114 as in the previous illustration. The outlet gas feed pipe 132 from the combination gas controller 130 is now connected to the safety relay valve 122, which in turn connected is to the burner feed pipe 134 on supply gas to the burner. The tank 106 is insulated within the square jacket 138, which also provides internal pathways for the air to be transferred from the top terminal 140 to the burner at the bottom of the appliance.
To help understand the control of the water heater, an understanding of a typical water heater combination gas controller 130 must first be had. To aid this, attention is now directed to the block diagram of
With this basic understanding in mind, attention is now directed to
In either physical layout, the safety relay valve 122 provides bleed gas to the pilot 152 in addition to the gas provided by functional activity block 142 when the thermostat 144 calls for heat. In this way, and as will be discussed in greater detail below, the means for ensuring ignition of the burner conserves energy and produces much less greenhouse gas over its lifetime as compared with the system illustrated in
In the illustrated embodiment relay gas valve uses small bore piping 120′ to direct the bypass gas to the proper chamber within the safety relay valve 122 as will be made clear below. However, it should be noted that this function distribution of bypass bleed gas may be provided by internal plumbing within the safety relay valve 122 in other embodiments. This embodiment in
In the embodiment illustrated in
As illustrated in
In another embodiment as illustrated in
The details of one embodiment of a safety relay valve 122 are shown in the cross sectional illustration of
A diaphragm 170 is positioned within the diaphragm control chamber 168, and is operatively coupled to the main valve control shaft 172. Displacement of the diaphragm 170 based on pressure within the diaphragm control chamber 168 will operate to open or allow the main controlling valve 158 to close under pressure of spring 160 as will be discussed more fully below. Diaphragm vent passage 180 will prevent any net pressure build up below the diaphragm 170 during displacement thereof. Once the main controlling valve 158 has been opened, gas is allowed to flow from the inlet 156 through the outlet 162 to the burner via the burner feed pipe 134. The safety relay valve 122 also includes a booster pilot gas connection 174 for providing gas to a booster pilot (either the dual function pilot 152 or the separate booster pilot 178). To allow the safety relay valve 122 to be used in installations such as that described in the above identified application that do not use a booster pilot, the bleed gas from the second connection port 166 can be distributed internally through passage 176 down stream of the valve 158, to outlet 162. Indeed, base on the relative size of this passage 176 to the booster pilot gas connection 174, this passage 176 can be included in embodiments of the present invention, or may be eliminated.
Turning now to
Besides the energy savings that the micro size pilot 152 provides, the life of the low mass thermocouple 154 is extended due to less burn out from the smaller micro-pilot flame. The micro pilot 152 also allows for faster heat up times because the low mass thermocouple 154 may now be more accurately positioned within the flame front of the micro-pilot flame for stable performance. Faster drop out times are also provided because with the low mass thermocouple 154 being positioned within the flame front, the gas issuing from the micro-pilot 152 will help cool the thermocouple 154 tip faster.
Once the safety relay valve has received the main gas flow, but before it opens its main controlling valve 158 (see
Once the thermostat 144 is satisfied, the combination gas controller 130 will disable the flow of gas to the safety relay valve 122. Without a supply of gas, the diaphragm control chamber 168 (see
As will now be clear to those skilled in the art in view of the foregoing, operation of embodiments of the present invention provide significant advantages over prior pilot systems in operation. Such operation begins when the thermostat in combination gas controller 130 calls for heat, and the internal gas valve opens allowing gas to flow through the combination gas controller 130 and the outlet gas feed pipe 132 to the inlet of the closed safety relay valve 122. A bypass flow of gas is piped from the inlet of the safety relay valve 122 though the micro bore piping 120 to the damper actuator valve 114 in embodiments that utilize the standby energy loss prevention system. If such a system is not used, the bypass gas is provided directly to the damper control chamber 168. The size of the micro bore piping 120 or the passage from the first connection port 164 to the second connection port 166 may vary somewhat, and is preferable in the range of about 3 mm to 5 mm aluminium tube for typical hot water heater installations.
The damper actuator valve 114 is pressurised by the bypass gas, forcing the damper flapper valve 118 to open. Continued flow of bypass gas to the damper actuator valve 114 will eventually drag the damper safety valve off its seat. As discussed above, the design is such that gas will not issue through the damper safety valve until the damper flapper valve 118 is sufficiently open for good combustion. The opened damper safety valve allows the gas to bleed from the damper actuator valve 114, through micro bore piping 128 back down to the top side of the diaphragm 170 in the safety relay valve 122. The flow of bypass gas from the damper actuator valve 114 is at a faster rate than issues from the booster pilot outlet 174, thus pressurizing the safety relay valve 122 diaphragm control chamber 168. The bleed gas starts to pressurize the relay diaphragm 170 and is also bled to the booster pilot 178 which ignites from the micro-pilot 152 in such embodiments that includes a booster pilot 178 (see
Once the safety relay valve 122 is finally pressurized, its main controlling valve 158 is forced open against the gas pressure and return spring force. Gas then issues to the main burner 148 via the burner feed pipe 134, where it is ignited by the pilot 152 or booster pilot 178. Gas continues to bleed from the top side of the diaphragm 170 of the safety relay valve 122 and continues to be burnt in the combustion chamber when the main burner 148 is on.
Once the combination gas controller 130 determines that the water temperature has reached its set point temperature, it turns off all gas to the safety relay valve 122. Gas drains out of the damper of the damper actuator valve 114 where upon the return spring, returns the push rod 192 to the original position rotating the crankshaft 190 which closes the damper flapper valve 118 and damper safety valve inside the damper actuator valve 114. Gas continues to drain from the damper safety valve bypass and from the diaphragm chamber of the safety relay valve 122, which allows the return spring to close off the main gas valve thus stopping all gas to the burner. The burner main flame is extinguished as well as the booster pilot leaving only the pilot or micro-pilot on.
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1581712 | Yoder | Apr 1926 | A |
| 1699297 | Ledbetter | Jan 1929 | A |
| 1715650 | Fonseca | Jun 1929 | A |
| 1813395 | Fraser | Jul 1931 | A |
| 1842337 | Te Pas | Jan 1932 | A |
| 1856489 | Lonergan et al. | May 1932 | A |
| 1856502 | Morley et al. | May 1932 | A |
| 1864515 | Beadle et al. | Jun 1932 | A |
| 1949030 | Stockmeyer | Feb 1934 | A |
| 1968319 | Shively | Jul 1934 | A |
| 2005224 | Dunham et al. | Jun 1935 | A |
| 2139344 | Andersen | Dec 1938 | A |
| 2196316 | Long | Apr 1940 | A |
| 2265210 | Waddell | Dec 1941 | A |
| 2297763 | Higley et al. | Oct 1942 | A |
| 2384314 | Koppel | Sep 1945 | A |
| 2437894 | Ray | Mar 1948 | A |
| 2478386 | Gauger | Aug 1949 | A |
| 2513578 | Matthews | Jul 1950 | A |
| 2513705 | Arden | Jul 1950 | A |
| 2516333 | Moore | Jul 1950 | A |
| 2592952 | Ray | Apr 1952 | A |
| 2635637 | Karrer | Apr 1953 | A |
| 2703095 | Ray | Mar 1955 | A |
| 2752870 | Short et al. | Jul 1956 | A |
| 2765029 | Wolff | Oct 1956 | A |
| 2833304 | Fish | May 1958 | A |
| 2916088 | Scogin | Dec 1959 | A |
| 2939524 | Mathis et al. | Jun 1960 | A |
| 2953198 | Hajny | Sep 1960 | A |
| 2986207 | Scogin | May 1961 | A |
| 3159202 | Weber | Dec 1964 | A |
| 3166248 | Fleer | Jan 1965 | A |
| 3167248 | Douglas | Jan 1965 | A |
| 3171468 | Sparrow | Mar 1965 | A |
| 3213922 | Weber | Oct 1965 | A |
| 3240241 | Kenney | Mar 1966 | A |
| 3308871 | Riehl | Mar 1967 | A |
| 3314604 | Branson | Apr 1967 | A |
| 3330133 | Kniebes | Jul 1967 | A |
| 3344989 | Willson | Oct 1967 | A |
| 3391867 | Zulian | Jul 1968 | A |
| 3402889 | Willson | Sep 1968 | A |
| 3405999 | Riehl | Oct 1968 | A |
| 3447775 | Katchka et al. | Jun 1969 | A |
| 3469567 | Bergquist | Sep 1969 | A |
| 3477462 | Ray | Nov 1969 | A |
| 3526360 | Ray | Sep 1970 | A |
| 3528452 | Willson | Sep 1970 | A |
| 3597138 | Ray | Aug 1971 | A |
| 3619095 | Genbauffe | Nov 1971 | A |
| 3692239 | Genbauffe | Sep 1972 | A |
| 3754563 | Boals | Aug 1973 | A |
| 3809313 | Branson | May 1974 | A |
| 3872877 | Branson | Mar 1975 | A |
| 3989188 | Branson | Nov 1976 | A |
| 3999932 | Matthews | Dec 1976 | A |
| 4060192 | Branson | Nov 1977 | A |
| 4076171 | Swenson | Feb 1978 | A |
| 4131413 | Ryno | Dec 1978 | A |
| 4159800 | Branson et al. | Jul 1979 | A |
| 4164936 | Dottore, Jr. | Aug 1979 | A |
| 4182483 | Swenson | Jan 1980 | A |
| 4192310 | Brodin | Mar 1980 | A |
| 4204833 | Kmetz et al. | May 1980 | A |
| 4225080 | Barth | Sep 1980 | A |
| 4264296 | Folkerts | Apr 1981 | A |
| 4266929 | Swenson | May 1981 | A |
| 4285662 | Katchka et al. | Aug 1981 | A |
| 4289271 | Barth | Sep 1981 | A |
| 4298336 | Riehl | Nov 1981 | A |
| RE30936 | Kmetz et al. | May 1982 | E |
| 4386731 | Barth | Jun 1983 | A |
| 4408567 | Morton | Oct 1983 | A |
| 4413975 | Turner et al. | Nov 1983 | A |
| 4770160 | Schimmeyer | Sep 1988 | A |
| 4778378 | Dolnick et al. | Oct 1988 | A |
| 5039006 | Habegger | Aug 1991 | A |
| 5039300 | Riehl | Aug 1991 | A |
| 5102039 | Yothers | Apr 1992 | A |
| 5121899 | Willson | Jun 1992 | A |
| 5239947 | Schimmeyer | Aug 1993 | A |
| 5275555 | Goodridge | Jan 1994 | A |
| 5393221 | McNally | Feb 1995 | A |
| 5447125 | McNally et al. | Sep 1995 | A |
| 5682841 | Schimmeyer et al. | Nov 1997 | A |
| 5732692 | Schimmeyer | Mar 1998 | A |
| 5911217 | Dameworth | Jun 1999 | A |
| 6418883 | Bourke et al. | Jul 2002 | B2 |
| 6546897 | Edds et al. | Apr 2003 | B1 |
| 6584940 | Khadkikar et al. | Jul 2003 | B1 |
| 6684821 | Lannes et al. | Feb 2004 | B2 |
| 7311064 | Schimmeyer | Dec 2007 | B2 |
| 20050066958 | Guzorek | Mar 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| 2409271 | Apr 2003 | CA |
| 2426723 | Jul 2003 | CA |
| 2482509 | Mar 2005 | CA |
| 0019671 | May 1979 | EP |
| 528827 | Nov 1940 | GB |
| 942650 | Nov 1963 | GB |
| 953982 | Apr 1964 | GB |
| 1 475 133 | Jun 1977 | GB |
| 56119420 | Sep 1981 | JP |
| 57188950 | Nov 1982 | JP |
| 58033050 | Feb 1983 | JP |
| 59157422 | Sep 1984 | JP |
| 60-226623 | Nov 1985 | JP |
| 62063140 | Mar 1987 | JP |
| 63021404 | Jan 1988 | JP |
| 4045320 | Feb 1992 | JP |
| 2007232262 | Sep 2007 | JP |
| WO 9517631 | Jun 1995 | WO |
| WO 0040906 | Jul 2000 | WO |
| WO 2006135319 | Dec 2006 | WO |
| Entry |
|---|
| U.S. Appl. No. 12/687,159, Whitford et al. |
| U.S. Appl. No. 12/175,551, Whitford et al, Jul. 18, 2008. |
| S. K. Sarkar, Flame traps-a technical note, journal, Jul. 1987, 5 pages, pp. 323-327, Journal of Mines, Metals & Fuels. |
| J. A. Harris et al., Flame stability-principles and practice, journal, Mar. 10, 1978, 22 pages, London and Southern Junior Gas Association. |
| Ken Lapp et al., Detonation Flame Arrester Qualifying Application Parameter for Explosion Prevention in Vapor Handling Systems, paper, Apr. 1995, 8 pages, pp. 139-146, Process Safety Progress (vol. 14, No. 2), Westech Industrial Ltd., 5636 Burbank Crescent , S.E., Calgary, Alberta, Canada T2H 1Z6. |
| R. P. Wilson et al., Flame Arrestor Design Requirements for Prolonged Exposure to Methane/Air, and Gasoline/Air Flames, report, Sep. 1978, 53 pages, Report No. CG-D-73-78, U.S. Department of Transportation, United States Coast Guard, Office of Research and Development, Washington, D.C. 20590. |
| Number | Date | Country | |
|---|---|---|---|
| 20100015559 A1 | Jan 2010 | US |
