Patent Application
20130104814
This disclosure relates to a hot water heater system (such as, for example, a gas-powered hot water heater system) that includes a self-powered automatic pilot light.
Conventional hot water heaters include a storage type hot water heater and a tankless type hot water heater.
Most household and commercial hot water heaters in use today are the storage-type hot water heaters, which have changed little in decades. They consist of a water tank that has a standing pilot light (i.e. a pilot light that is always on) and a single thermo-mechanical bimetallic gas valve underneath. When the water in the tank cools to below the set temperature threshold of a thermostat in the thermo-mechanical gas valve, the cooling causes the thermo-mechanical valve to open which allows the gas to flow to the main burner and be lighted by the standing pilot light. When the water temperature in the tank rises and satisfies the set temperature threshold of the thermostat in the thermo-mechanical gas valve, the valve is then closed. Such mechanism is entirely mechanical, with no electrical power required.
Conventional storage-type hot water heaters also generally include a safety mechanism that is similarly mechanical in nature. The safety mechanism includes a spring loaded, normally closed valve that prevents the gas (which flows though the opened thermo-mechanical valve) from flowing to the main burner. The spring-loaded, normally closed valve may be held open by the heat of the pilot (e.g. via a thermocouple) after the pilot light is manually lit. If for any reason the pilot light fails or blows out, the flow of unlit gas must be stopped, and so the loss of the heat from the pilot light causes the safety mechanism to be triggered, allowing the spring to force close the safety valve, stopping the flow of gas to the entire system.
While such storage-type hot water heaters are safe, consistent, long lasting, and relatively inexpensive, there is a significant drawback in that storage-type hot water heaters require a standing pilot light to be lit 24 hours a day. Thus, over the course of time, a significant amount of gas may be consumed in order to keep the pilot light lit at all times, and when multiplied by the millions of hot water heaters currently in use, the amount of gas consumed becomes extremely large. Indeed, it is estimated that if all of the pilot lights on all of the gas fired storage hot water heaters in use today were eliminated, it will save consumers in the United States $1.66 billion dollars each year, and it will save the United States over 132 billion cu. ft. of natural gas and/or propane (both of which are non-renewable energy sources) each year.
The other type of conventional hot water heater is the instant, tankless type hot water heater. These are tankless devices that turn on as soon as water flow is detected. Energy is saved by not having a tank of water to keep hot 24 hours a day, although it is estimated that the savings for the typical consumer switching to the tankless type hot water heaters is only about $70-$80 per year.
However, tankless type hot water heaters have several drawbacks. For example, they have a very large initial cost, especially in a retrofit configuration. Further, in addition to purchasing the unit itself, the total expense is significantly increased by the necessity for re-piping in a large gas line to keep up with the high gas draw, as well as the possibility of having to re-pipe the water lines. In addition, an external electrical service or power source (such as connection to external electrical main lines or external power outlets) may be required, which is typically not necessary in the older storage type units and may lead to the entire hot water heater becoming un-usable and non-functional if there is a loss of external power (such as during a power blackout). Another drawback is that some units will give a ‘cold water sandwich’ (that is, output cool, or even cold, water) when the hot water tap is turned on, until the hot water heater unit cycles on and starts to produce hot water. In addition, there are going to be many instances where it is not feasible to install tankless type hot water heaters, especially in older buildings.
There remains a need for a hot water heater that is fail-safe, long lasting, relatively inexpensive, has similar connections to traditional storage tank type hot water heaters (so that little or no piping changes are necessary), but that also eliminates the standing pilot light (in contrast to the conventional storage type hot water heaters that require a standing pilot light), and that also requires no external power (in contrast to the conventional tankless type hot water heaters that require external power).
In an aspect of this disclosure, there is provided a hot water heating system that includes a self-powered automatic pilot light.
In another aspect, the pilot light only remains lit when there is a need to heat water in a water tank. For example, the pilot light only remains lit when the temperature of the water in the water tank is below a given threshold.
In another aspect, the hot water heating system including the automatic pilot light is self-powered and is not connected to an external source of electrical power.
In another aspect, a water heating system comprises: a water tank; a main burner configured to heat water in the water tank; and a pilot light configured to ignite fuel to light the main burner. Moreover, a first thermo-mechanical valve unit monitors temperature of the water and determines whether the temperature of the water is below a first threshold, and permits fuel to flow to the pilot light, when the first thermo-mechanical valve unit determines that the temperature of the water is below the first threshold. An ignition unit ignites the pilot light, when the first thermo-mechanical valve unit permits fuel to flow to the pilot light. A second thermo-mechanical valve unit monitors temperature near the pilot light and determines whether the pilot light is ignited, and permits fuel to flow to the main burner and be ignited by the pilot light, when the second thermo-mechanical valve unit determines that the temperature near the pilot light is above a second threshold.
In another aspect, the first thermo-mechanical valve unit prevents fuel from flowing to the pilot light, and thereby causing the pilot light to be extinguished, when the first thermo-mechanical valve unit determines that the temperature of the water is equal to or greater than the first threshold.
In another aspect, the second thermo-mechanical valve unit prevents fuel from flowing to the main burner, and thereby shutting off the main burner, when the second thermo-mechanical valve unit determines that the ambient temperature near the pilot light is equal to or below the second threshold.
In another aspect, a switch closes when the first thermo-mechanical valve unit permits fuel to flow to the pilot light. Moreover, an electronic controller controls the ignition unit to ignite the pilot light, when the electronic controller determines that the switch is closed.
In another aspect, a solenoid piston opens a safety valve of the first thermo-mechanical valve unit for a predetermined time period to permit fuel to flow to the pilot light. The electronic controller controls the solenoid piston to open the safety valve for the predetermined time period, when the electronic controller determines that the switch is closed.
In another aspect, after the solenoid piston is deactivated after the predetermined time period, a thermocouple powered by heat from the pilot light keeps the safety valve open to continue permitting fuel to flow to the pilot light after the solenoid piston is deactivated.
In another aspect, a battery supplies electronic power to the electronic controller, the ignition unit, and the solenoid piston.
In another aspect, a thermopile converts heat generated from the ignited main burners into electrical energy to recharge the battery.
In another aspect, a solar cell converts light generated from the ignited main burners into electrical energy to recharge the battery.
The aforementioned and other aspects, features and advantages can be more readily understood from the following detailed description with reference to the accompanying drawings wherein:
In describing preferred embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner. In addition, a detailed description of known functions and configurations will be omitted when it may obscure the subject matter of the present invention.
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, there is described a hot water heater system (such as, for example, a gas-powered hot water heater system) that includes a self-powered automatic pilot light.
For example,
TMV Unit A 20 includes a probe or sensor 20a connected to the water tank 10, and which may extend into the interior of the water tank 10 and/or contact the water inside the water tank 10. The probe 20a is connected to a thermostat 20b that, together with the probe 20a, determine the temperature of the water tank 10 and/or the water inside the water tank 10, and determine whether the measured temperature is lower than a first threshold that is set or stored in the thermostat 20b. If the measured temperature is indeed lower than the first threshold, TMV Unit A opens a main valve 20d that permits a fuel supply received via input pipe 20c to flow out through output pipe 20e and flow towards the pilot light. In this way, pilot light 30 has a supply of fuel so that the pilot light can be lit, by the ignition unit 40 described below. Thus, TMV Unit A determines whether the temperature of the water in the water tank 10 is below a first threshold, and permits fuel to flow to the pilot light 30, when a first temperature measuring unit (probe 20a and/or thermostat 20b) of TMV Unit A determine that the temperature of the water is below the first threshold.
The ignition unit 40 may include a sparker and sparker controller, and is configured to ignite the pilot light, when the TMV Unit A opens the main valve 20d and permits fuel to flow to the pilot light 30. Thus, the pilot light 30 is not a standing pilot light that is constantly lit. Instead, pilot light 30 is an automatic pilot light that is only lit by the ignition unit when the TMV Unit A opens the main valve 20d and permits fuel to flow to the pilot light 30 (i.e. the pilot light 30 is only lit when the TMV Unit A determines that the temperature of the water in the water tank 10 is below a first threshold). The operation of the ignition unit 40 will be described in further detail below.
TMV Unit B 50 includes a probe or sensor 50a that is placed near the pilot light 30 and detects the ambient temperature near the pilot light 30. The probe 50a is connected to a thermostat 50b that, together with the probe 50a, determine the ambient temperature near the pilot light 30, and determine whether the ambient temperature is above a second threshold that is set or stored in the thermostat 50b. If the measured ambient temperature is indeed above the second threshold, TMV Unit B determines that the pilot light 30 is lit, opens a main valve 50d that permits a fuel supply received via input pipe 50c to flow out through output pipe 50e and flow towards the pilot light 30 and towards the main burner 60. The pilot light 30 will then light the fuel exiting the output pipe 50e and light the main burner 60 in order to heat the water in water tank 10. Thus, TMV Unit B determines whether the pilot light is ignited (by determining whether the ambient temperature near the pilot light is above a second threshold), and permits fuel to flow to the main burner 60 and be ignited by the pilot light 30, when a second temperature measuring unit (probe 50a and/or thermostat 50b) determines that the ambient temperature near the pilot light 30 is above the second threshold.
As a result of the aforementioned steps, the lit main burner 60 will heat the water in the water tank 10. Eventually, the temperature of the main tank 10 (or water in the main tank 10) will increase to satisfy the first threshold set in the thermostat 20b of the TMV Unit A 20. When the first temperature measuring unit (probe 20a and/or thermostat 20b) determines that the temperature of the water is equal to or greater than the first threshold, TMV Unit A will close the main valve 20d to prevent fuel from flowing out of the output pipe 20e to the pilot light 30. Without this supply of fuel to the pilot light 30, the pilot light 30 will be extinguished.
Thereafter, the ambient temperature around the extinguished pilot light will decrease to satisfy the second threshold set in the thermostat 50b of the TMV Unit B 50. When the second temperature measuring unit (probe 50a and/or thermostat 50b) determines that the ambient temperature near the pilot light is equal to or below the second threshold, TMV Unit B will close the main valve 50d to prevent fuel from flowing out of the output pipe 50e to the main burner 60. Without this supply of fuel to main burner 60, the main burner 60 will be extinguished.
It should be noted that the first temperature threshold corresponding to the thermostat of TMV Unit A is variable, based on user adjustment of an interface (e.g. thermostat knob) of TMV Unit A in order to set a desired water temperature. On the other hand, the second temperature threshold corresponding to the thermostat of TMV Unit B is generally pre-set by the manufacturer of TMV Unit B, and is generally not user settable.
All of the aforementioned operations (apart from ignition by the ignition unit 40) are strictly thermo-mechanical operations that do not require any source of electrical power.
Turning now to
As seen in
That is, output pipe 20e of TMV Unit A may include a spring loaded, normally closed safety valve 90 that prevents the gas (which flows though the opened main valve 20d) from flowing to the pilot light. The spring-loaded, normally closed valve may be held open by the heat of the pilot after the pilot light is lit. For example, the heat of the pilot light flame can be used to generate electrical energy with a thermocouple (not shown), and the generated energy may be used to power a solenoid to force open the spring-loaded, normally closed safety valve 90, thereby allowing the gas to flow from the opened thermo-mechanical valve to the pilot light. If for any reason the pilot light fails or blows out, the flow of unlit gas must be stopped, and so the loss of the heat from the pilot light causes the safety mechanism to be triggered, allowing the spring to force close the safety valve 90, stopping the flow of gas to the pilot light.
According to the aspects of this embodiment, when the pilot light needs to be lit, the electronic controller: (1) controls a solenoid piston 82 to open the safety valve 90 for a predetermined time period (e.g. 60 seconds) to permit fuel to flow through output pipe 20e to the pilot light 30 and (2) controls the ignition unit 40 to light the pilot light with use of the fuel flowing through output pipe 20e. The electronic controller does both (1) and (2) only when the electronic controller determines that the switch 80 is closed (which occurs when TMV Unit A opens main valve 20d to allow fuel to enter output pipe 20e). After the solenoid piston 82 is deactivated by the electronic controller 81 after the predetermined time period has expired, a thermocouple (not shown) powered by heat from the pilot light 30 keeps the safety valve 90 open to permit fuel to keep flowing to the pilot light 30.
Thus, the hot water heating system of this disclosure may use a conventional thermo-mechanical valve unit with the same safety valve that is used in an existing storage type of hot water heater, supplementing it with a solenoid so that the piston of the solenoid is in alignment with a push button of the safety valve. When there is a call for hot water, the solenoid actuates for 60 seconds which causes its piston to push down the safety valve, opening the gas. After 60 seconds, the solenoid shuts down with the spring returning the piston to its at-rest position. The pilot flame will now keep the safety valve open. If there is a flame failure, the safety valve shuts off the gas just as it does with a traditional hot water heater. If there is an electrical failure, the safety valve remains shut. This creates a failsafe environment.
The aforementioned operations of the electronic controller 81, solenoid 82 and ignition unit 40 are the only electrically-power operations of the hot water heating system 100 of this disclosure. Electronic power for operations of the electronic controller 81, solenoid 82 and ignition unit 40 is supplied by the battery 85. In the aspects of this disclosure, a thermopile 84 converts heat generated from the ignited main burner 60 into electrical energy to recharge the battery 85. Instead, or in addition, a solar cell 83 converts light generated from the ignited main burner 60 into electrical energy to recharge the battery 85. The configuration of the solar cell 83 is preferably optimized for generating energy from the portion of the visible light spectrum corresponding to the gas flames emitted from the main burner 60, in order to maximize the recharging abilities of the solar cell 83. Thus, the entire hot water heating system of this disclosure is self powered, since TMV Units A and B are strictly thermo-mechanical devices, and the electronic controller 81, solenoid 82 and ignition unit 40, battery 85, etc., receive power from the ignited main burners 60 via a solar cell or thermopile.
The battery requirements of the hot water heating system of this disclosure are quite modest. Electrical power is only briefly used at the beginning of each cycle to run the sparker which lights the pilot light and to actuate the safety solenoid/valve combination for 60 seconds. Otherwise, the system is thermo-mechanical.
Thus, according to this exemplary embodiment, there is provided a hot water heating system with an automatic pilot light that is only lit when there is a need to heat water in a water tank (i.e. when the temperature of the water in the water tank is below a first threshold). Moreover, the entire system is completed self-powered, and is not connected to an external source of electrical power.
Turning now to
First, the thermostats knob of the thermostat 20b is set to the desired temperature, i.e. the first temperature threshold (S301). Water in the water tank 10 cools (S302). When the water in the tank cools to below the set temperature threshold (S303, Yes), TMV Unit A 20 is triggered which opens the main pilot valve 20d and feeds fuel such as natural gas or propane to the output pipe 20e (S304). This action also causes the electronic controller 81 to activate the solenoid piston 82 for a predetermined time period (e.g. 60 seconds) which causes its piston to push down and open the safety valve 90, opening the fuel to flow through the output pipe 20e to the pilot light 30. The closing of switch 80 also causes the electronic controller 81 to actuate the sparker 40b, which may be powered by a 12 volt on-board battery 85. (When a flame is evident, the sparker 40b as is typically designed, automatically stops sparking). If the pilot light does not light in the predetermined time period (S305, No), the sparker 40b and solenoid 82 are deactivated (S306), and the safety system (e.g. thermocouple) normally powered by the heat of the pilot light will allow the safety valve 90 to close (S307). If the pilot light is lit (S305, Yes), the sparker 40b and solenoid 82 are deactivated after the predetermined time period (S308), and the safety system (e.g. thermocouple) powered by the heat of the pilot light will keep the safety valve 90 open.
Located near the pilot flame is the temperature sensing means (probe 50a and thermostat 50b) of TMV Unit B 50. When the pilot flame is lit, the pilot flame heats the temperature sensing means at TMV Unit B (S309), and once the detected temperature is higher than the second temperature threshold set at thermostat 50b (S310, Yes), TMV Unit B will cause the main valve 50d to open to permit fuel to flow through output pipe 50e towards the main burner 60 to be lit by the pilot light 30 (S311). This in turn heats the water in the water tank 10 (S312). In addition, while the main burner 60 is firing, the light and/or heat created by the flame of the burner recharges the on-board battery 85 to maintain electrical self-sufficiency in the system. The recharging is done by either solar cells 83 within the confines of the tank housing or by converting heat directly to electrical power via a thermopile 84.
Once the tank water is sufficiently heated to satisfy the first threshold temperature set at thermostat 20a of TMV Unit A 20 (S313, Yes), TMV A will close the main valve 20d, shutting off the flow of gas to the pilot light 30 (S314) to thereby extinguish the pilot light 30. With no pilot flame near the sensor 50a of TMV Unit B, the sensor cools down and the thermostat 50b determines that the ambient temperature around the pilot light drops below the second threshold set at thermostat 50b. As a result, TMV Unit B will close main valve 50d, preventing the flow of fuel to main burner 60 and shutting down the main burner 60 (S315).
What follows are illustrative examples of components that can be used to form the various parts of the hot water heating system illustrated in
Thermo-mechanical valve A (TMV Unit A 20): This may be an off the shelf hot water heater controller except the pilot/safety valve is used as a safety valve 90 only. There is a solenoid piston 82 directly above the push button of the safety valve 90 which can push down engaging the push button, holding it open for 60 seconds. This will allow the pilot light 30 to be lit long enough for it to stay open on its own. The main valve is being used as a pilot valve 20d. In addition, the pilot valve 20d includes or is connected to a small reed or magnetic switch 80 to indicate the valve position to the controller 81. This is so the controller knows when there is a call for hot water so it can actuate the solenoid 82 and sparker 40b.
Thermo-mechanical valve B (TMV Unit B 50): This may also be an off-the-shelf hot water heater controller with a few minor modifications. First the pilot/safety valve is not used and is blocked open. Next, the main valve 50d is modified to function backwards. In other words when the sensor 50a is heated past the temperature threshold, the valve 50d opens and when the sensor 50a cools, the valve 50d closes. Finally, the temperature sensing means 50a has a much smaller mass so the valve will react faster. A longer, heavier sensing means is not necessary since there is no immersion in a liquid.
Main Burner 60 and Pilot 30: May be off-the-shelf except they are separated by a few inches with a tube between them to insure the flame can travel from the pilot to the main burner.
Sparker Controller 40a and Sparker 40b: May be off-the-shelf D.C. version.
Battery 85: May be off-the-shelf 12 volt rechargeable lead acid typical of what is used in emergency lighting and alarm system backups.
Solar cells 83 or thermopile 84: May be off-the-shelf.
Solenoid A 82: Located above the safety valve 90 push button. It will energize for 60 seconds starting when there is a call for hot water at TMV A. The solenoid 82 piston engages the safety valve 90, opening it for the 60 seconds. After 60 seconds the solenoid 82 is de-energized and the spring returns it to its at-rest position.
Controller/circuit board 81: One purpose of the controller/circuit board is to actuate the solenoid 82 and time its action for 60 seconds. The trigger is the switch 80 located at TMV Unit A 80 which closes every time there is a call for hot water and the valve 20d at TMV Unit A opens. After 60 seconds, the solenoid 82 is de-energized and the mechanical cycle continues on to fire the main burner 60. If a reset is required, simply turning the temperature dial of thermostat 20b to cool and then back to hot will trigger the solenoid and sparker once again. Another function of the controller/circuit board is to correct the voltage output of the power producing components to enable recharging of the battery 85 and also to prevent its overcharging.
Turning now to
In particular,
One difference between hot water heater system of
The second embodiment of
This is addressed with some additional components. The pilot valve 20d automatically and mechanically latches closed when the hot water temperature at thermostat 20b is satisfied. Once the main valve 50d closes as determined by a reed or magnetic switch connected to the main valve 50d (which indicates valve position of the main valve 50d), a second solenoid, Solenoid B (not shown) momentarily energizes to unlatch the pilot valve 20d to allow it to open the next time there is a call for hot water. While the pilot valve 20d is latched closed, the pilot valve 20d cannot open under any circumstances, until the main valve 50d cools and closes-which in turn triggers the Solenoid B to unlatch the pilot valve 20d. This is a fail-safe method of preventing fast cycling. This safety system can also be applied to the first embodiment if
Turning now to
The method of
Another difference is that, once the tank water is sufficiently heated to satisfy the first threshold temperature set at thermostat 20a of TMV Unit A 20 (S513, Yes), TMV Unit A will close the valve 20d (S514) and shut off the flow of gas to both: (1) the pilot light 30, to thereby extinguish the pilot light 30; and (2) the input pipe 50c-1 of TMV Unit B, to prevent the flow of fuel to main burner 60 to thereby extinguish the main burner 60. Moreover, in S514, the pilot valve 20d is latched closed.
Further, with no pilot flame near the sensor 50a of TMV Unit B, the sensor cools down and the thermostat 50b determines that the ambient temperature around the pilot light drops below the second threshold set at thermostat 50b. As a result, TMV Unit B will close main valve 50d (S515). This also results in Solenoid B pulsing to unlatch the pilot valve 20d of TMV Unit A for the next cycle (S515).
What follows are illustrative examples of components that can be used to form the various parts of the hot water heating system 400 of the embodiment illustrated in
TMV Unit A 20: There may be an additional mechanical latching mechanism when compared to the embodiment of
TMV Unit B 50: Like TMV Unit A, there may be a switch (e.g. reed or magnetic switch) which acts as a position sensor to the controller 81. This is used to let the controller 81 know that valve 50d of TMV Unit B has closed, so that the controller 81 can cause solenoid B to pulse unlatching valve 20d of TMV Unit A (protection against fast cycling).
Controller 81: In the embodiment of
Solenoid B: Located at TMV Unit A. Once the tank temperature satisfies the temperature threshold set in thermostat 20b, TMV Unit A will close valve 20d and then shortly thereafter and TMV Unit B will close valve 50d. Once this occurs, the solenoid B is momentarily energized to unlatch the locking mechanism, allowing TMV Unit A to open valve 20d the next time there is a call for hot water.
According to the embodiments of this disclosure, there is described a hot water heating system that is safe, reliable, and relatively simple, and inexpensive, but has the advantage of electronic ignition, no standing pilot, and a self-sufficient electrical environment with recharging done by either solar cells or thermopile. If all of the conventional storage-type of hot water heaters are taken as a group and converted to the systems of this disclosure, an enormous amount of money and gas may be saved long after the initial, additional investment is amortized.
The aforementioned specific embodiments are illustrative, and many variations can be introduced on these embodiments without departing from the spirit of the disclosure or from the scope of the appended claims. For example, elements and/or features of different examples and illustrative embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.
