Combustion device and method for operating the same

Abstract

A combustion device and a method for operating the same are disclosed. The combustion device uses at least 90 wt% of a propylene glycol-based liquid fuel and includes a first fuel tank, a second fuel tank, a pipe, and a driving unit. The first fuel tank is configured to contain the propylene glycol-based liquid fuel and is provided with a metal wick. A sensing unit is disposed in the first fuel tank and is configured to receive a start signal and to sense a liquid level of the propylene glycol-based liquid fuel in the first fuel tank, and to send a refueling signal. The second fuel tank is configured to contain the propylene glycol-based liquid fuel. The pipe is configured to communicate the first fuel tank and the second fuel tank. The driving unit is disposed on the pipe and is configured to receive the refueling signal, and to supplement the propylene glycol-based liquid fuel in the second fuel tank to the first fuel tank via the pipe, so as to achieve the effects of automatic refueling and cooling the wick.

Description

Technical Field

[0001] This invention relates to a combustion device and its operation method. Background Technology

[0002] Modern combustion devices, such as fireplaces used for creating ambiance, mostly use ethanol-based fuel, a highly flammable liquid. Filling this fuel can lead to explosions or burns, especially if the fireplace is completely extinguished or has cooled sufficiently. Another risk is that if the fireplace accidentally tips over, ethanol-based fuel will cause the fire to spread rapidly. While isopropanol is also frequently used as fuel, it shares similar drawbacks with ethanol-based fuels.

[0003] Currently, it has been found that using propylene glycol-based fuel can overcome the above problems. Propylene glycol-based fuel contains at least 60 wt% propylene glycol and has a flash point of at least 50°C, which can even reach 104°C depending on the blending ratio. Therefore, propylene glycol-based fuel is actually a non-flammable but combustible liquid fuel. "Non-flammable" means it will not ignite when in contact with a flame (such as a match) at room temperature, and "combustible" means it can burn under suitable conditions. Moreover, when propylene glycol-based fuel burns, it will extinguish itself if poured onto a surface at the same ambient temperature, preventing the fire from spreading.

[0004] For fuel, a wick is essential for ignition, through which the fuel is transported via capillary action. The wick can be made of, for example, glass fiber, ceramic fiber, silicate fiber, or rock wool, or polymeric materials such as aromatic polyamide fibers, cotton, or porous materials such as pumice, or other wick materials known in the art. Metal wicks, compared to wicks made of other materials, do not produce carbonization or loss during combustion and are more suitable for the complete combustion of propylene glycol-based liquid fuels. However, metal wicks have the problem of overheating due to the high thermal conductivity of metal, affecting flame size and causing heat to transfer from the flame tip to the fuel.

[0005] Furthermore, when the flame goes out, the wick and fuel remain hot, indicating that the fuel is evaporating and producing exhaust fumes containing toxic chemicals. Although propylene glycol-based fuels are considered to have low smoke toxicity, even the smallest amounts of toxic chemicals raise concerns about their potential health risks, thus requiring solutions to ensure that combustion devices can be used in environments with children and pregnant women. Summary of the Invention

[0006] The purpose of this invention is to provide a combustion device and its operation method, which can automatically replenish fuel, effectively extinguish flames, and achieve the effects of cooling and exhaust gas extraction.

[0007] To achieve the above objectives, the present invention provides a combustion device that uses at least 90 wt% propylene glycol-based liquid fuel and comprises:

[0008] A first fuel tank is provided for containing the propylene glycol-based liquid fuel and a metal wick for transmitting the propylene glycol-based liquid fuel is inserted therein. A sensing unit is provided in the first fuel tank. The sensing unit is configured to receive a start signal and sense the liquid level of the propylene glycol-based liquid fuel in the first fuel tank, thereby issuing a refueling signal.

[0009] A second fuel tank for containing the propylene glycol-based liquid fuel;

[0010] A pipeline connecting the first fuel tank and the second fuel tank; and

[0011] A drive unit is disposed on the pipeline and is configured to receive the refueling signal, thereby replenishing the propylene glycol-based liquid fuel in the second fuel tank to the first fuel tank via the pipeline, and cooling the lamp wick by the propylene glycol-based liquid fuel from the second fuel tank.

[0012] In one embodiment of the invention, the drive unit is configured to receive an additional shut-off signal, thereby drawing propylene glycol-based liquid fuel from the first fuel tank to the second fuel tank via the pipeline.

[0013] In one embodiment of the present invention, the drive unit is configured to receive the shutdown signal and continue to operate for a predetermined time after pumping the propylene glycol-based liquid fuel in the first fuel tank to the second fuel tank.

[0014] In one embodiment of the present invention, the volume of the first fuel tank is smaller than the volume of the second fuel tank.

[0015] In one embodiment of the present invention, the volume of the second fuel tank is at least ten times the volume of the first fuel tank.

[0016] In one embodiment of the present invention, the propylene glycol-based liquid fuel comprises 95 wt% propylene glycol.

[0017] In one embodiment of the present invention, the pipeline includes a first pipe section connecting the first fuel tank and the drive unit and a second pipe section connecting the drive unit and the second fuel tank.

[0018] In one embodiment of the present invention, the drive unit includes a motor.

[0019] In addition, the present invention also provides a method for operating a combustion device, the combustion device using at least 90 wt% propylene glycol-based liquid fuel and comprising:

[0020] A first fuel tank is provided for holding the propylene glycol-based liquid fuel and a metal wick for transmitting the propylene glycol-based liquid fuel is inserted therein. A sensing unit is provided inside the first fuel tank.

[0021] A second fuel tank for containing the propylene glycol-based liquid fuel;

[0022] A pipeline connecting the first fuel tank and the second fuel tank; and

[0023] A drive unit is installed on this pipeline;

[0024] The operation method of the combustion device includes the following steps: the sensing unit receives a start signal and senses the liquid level of the propylene glycol-based liquid fuel in the first fuel tank, and sends a fuel replenishment signal accordingly; the drive unit receives the fuel replenishment signal and replenishes the propylene glycol-based liquid fuel in the second fuel tank to the first fuel tank through the pipeline, and cools the lamp wick by the propylene glycol-based liquid fuel from the second fuel tank.

[0025] In one embodiment of the present invention, the method further includes the following steps: the drive unit receives a shutdown signal, thereby drawing propylene glycol-based liquid fuel from the first fuel tank to the second fuel tank via a pipeline; after receiving the shutdown signal and drawing propylene glycol-based liquid fuel from the first fuel tank to the second fuel tank, the drive unit continues to operate for a predetermined time, thereby delaying the shutdown of the drive unit to extract exhaust gas.

[0026] Based on the above, the combustion device and its operation method provided in this embodiment of the invention are configured by a drive unit to receive a fuel replenishment signal from a sensing unit, thereby replenishing the first fuel tank with propylene glycol-based liquid fuel from the second fuel tank via a pipeline, achieving the effect of automatic fuel replenishment. Furthermore, the drive unit is configured to also receive a shut-off signal, thereby drawing the propylene glycol-based liquid fuel from the first fuel tank to the second fuel tank via a pipeline, effectively extinguishing the flame and achieving a cooling effect. Further, the drive unit is configured to continue operating for a predetermined time after receiving the shut-off signal and drawing the propylene glycol-based liquid fuel from the first fuel tank to the second fuel tank, thereby removing exhaust gases.

[0027] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Attached Figure Description

[0028] Figure 1 This is a three-dimensional external schematic diagram of an embodiment of the combustion device of the present invention.

[0029] Figure 2 yes Figure 1 A partial cross-sectional schematic diagram of the combustion device shown.

[0030] Figure 3 This is a flowchart of the operation method of the combustion device of the present invention.

[0031] [Symbol Explanation]

[0032] 10: First fuel tank; 11: Metal lamp wick; 12: Sensing unit; 20: Second fuel tank; 30: Pipeline; 31: First pipe section; 32: Second pipe section; 40: Drive unit; 41: Motor. Detailed Implementation

[0033] Some embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Component symbols used in the following description, when appearing in different drawings, are considered to be the same or similar components. These embodiments are only a part of the present invention and do not disclose all possible implementations of the invention. More precisely, these embodiments are merely examples of combustion devices within the scope of the claims of the present invention.

[0034] Please refer to Figure 1 and Figure 2 This is a schematic diagram of the external appearance and a partial cross-sectional view of an embodiment of the combustion device of the present invention. The combustion device shown in this embodiment uses at least 90 wt% propylene glycol-based liquid fuel. The combustion device includes a first fuel tank 10, a second fuel tank 20, a pipeline 30, and a drive unit 40. The first fuel tank 10 is used to hold the propylene glycol-based liquid fuel and houses a metal wick 11 for transmitting the propylene glycol-based liquid fuel. A sensing unit 12 is disposed within the first fuel tank 10. The sensing unit 12 is configured to receive a start signal and sense the liquid level of the propylene glycol-based liquid fuel in the first fuel tank 10, thereby issuing a fuel replenishment signal. The second fuel tank 20 is used to hold the propylene glycol-based liquid fuel. The pipeline 30 connects the first fuel tank 10 and the second fuel tank 20. The drive unit 40 is disposed on the pipeline 30 and is configured to receive a fuel replenishment signal, thereby replenishing the first fuel tank 10 with propylene glycol-based liquid fuel in the second fuel tank 20 via the pipeline 30, thereby achieving the effect of automatically replenishing fuel and cooling the metal wick 11 with propylene glycol-based liquid fuel from the second fuel tank 20.

[0035] Furthermore, before the metal wick 11 is lit, the sensing unit 12 can sense the liquid level of propylene glycol-based liquid fuel in the first fuel tank 10 in advance. If the liquid level is low, it sends a refueling signal to the drive unit 40, so that the drive unit 40 replenishes the propylene glycol-based liquid fuel in the second fuel tank 20 to the first fuel tank 10 through the pipeline 30 to reach a high liquid level. Conversely, if the liquid level is high, the user can light the metal wick 11. When the metal wick 11 is ignited and begins to transfer propylene glycol-based liquid fuel from the first fuel tank 10 to generate a flame at its tip, once the sensing unit 12 senses that the propylene glycol-based liquid fuel in the first fuel tank 10 has been consumed to a low level, it sends a refueling signal to the drive unit 40, causing the drive unit 40 to replenish the first fuel tank 10 with propylene glycol-based liquid fuel from the second fuel tank 20 via the pipeline 30. The propylene glycol-based liquid fuel from the second fuel tank 20 not only supplies fuel to maintain the flame, but also cools the metal wick 11 that is currently being heated by the flame, thereby achieving the effect of automatically replenishing fuel and cooling the metal wick 11, while preventing the metal wick 11 from being affected by overheating and affecting the flame size and shape. The aforementioned effects are specifically based on the high flash point characteristics of propylene glycol-based fuel. Propylene glycol-based liquid fuel from the second fuel tank 20 is used to cool the metal wick 11 that has been heated by the flame and to stabilize the flame size and shape. Ethanol or isopropanol-based fuels cannot be used in this way because their flash point is extremely low. They are ignited as soon as they come into contact with the metal wick 11 heated by the flame and cannot be used to cool the metal wick 11 at all.

[0036] Furthermore, the drive unit 40 is configured to receive a shutdown signal, thereby drawing propylene glycol-based liquid fuel from the first fuel tank 10 to the second fuel tank 20 via the pipeline 30. Therefore, when the metal wick 11 is lit, once the drive unit 40 receives the shutdown signal, it begins drawing propylene glycol-based liquid fuel from the first fuel tank 10 to the second fuel tank 20 until the propylene glycol-based liquid in the first fuel tank 10 reaches a low level, preventing the metal wick 11 from producing a flame, or until all the propylene glycol-based liquid fuel in the first fuel tank 10 is drawn to the second fuel tank 20, extinguishing the flame at the tip of the metal wick 11. Since the metal wick 11 conducts heat from the flame tip to the propylene glycol-based liquid fuel in the first fuel tank 10 when it is lit, it can also be cooled down by pumping it to the second fuel tank 20, or better yet, to the ambient temperature. This also utilizes the high flash point of the propylene glycol-based fuel, using the propylene glycol-based liquid fuel in the second fuel tank 20 to cool down the propylene glycol-based liquid fuel from the first fuel tank 10.

[0037] Furthermore, the drive unit 40 is configured to receive a shutdown signal and pump the level of propylene glycol-based liquid fuel in the first fuel tank 10 to a height that cannot be transmitted by the metal wick 11 to generate a flame, or to continue operating for a predetermined time after completely pumping the propylene glycol-based liquid fuel in the first fuel tank 10 to the second fuel tank 20 (as sensed by the sensing unit 12), thereby delaying the shutdown of the drive unit 40 to remove the exhaust gas generated by the flame at the end of the metal wick 11 being extinguished.

[0038] To improve the cooling efficiency of the fuel, the volume of the first fuel tank 10 in this embodiment is smaller than the volume of the second fuel tank 20, and more preferably, the volume of the second fuel tank 20 is at least ten times the volume of the first fuel tank 10.

[0039] Furthermore, the combustion device of this embodiment uses at least 90 wt% propylene glycol-based liquid fuel, more preferably containing 95 wt% propylene glycol.

[0040] In this embodiment, the pipeline 30 may include a first pipe section 31 connecting the first fuel tank 10 and the drive unit 40, and a second pipe section 32 connecting the drive unit 40 and the second fuel tank 20.

[0041] The drive unit in this embodiment includes a motor 41, which can replenish the propylene glycol-based liquid fuel in the second fuel tank 20 to the first fuel tank 10 via the pipeline 30, or draw the propylene glycol-based liquid fuel in the first fuel tank 10 to the second fuel tank 20 via the pipeline 30.

[0042] Please refer to the following: Figure 3 This is a flowchart illustrating the operation method of the combustion device of the present invention. The operation method of the combustion device of the present invention includes the following steps:

[0043] The aforementioned combustion device has been described in detail above and will not be repeated here.

[0044] The sensing unit 12 receives a start signal and senses the liquid level of propylene glycol-based liquid fuel in the first fuel tank 10. If the liquid level is low, a refueling signal is issued; otherwise, if the liquid level is high, the metal wick 11 can be ignited.

[0045] The drive unit 40 receives a refueling signal and accordingly replenishes the first fuel tank 10 with propylene glycol-based liquid fuel from the second fuel tank 20 via the pipeline 30, raising the propylene glycol-based liquid fuel level in the first fuel tank 10 to a high level. This level is sufficient to ignite the metal wick 11 or maintain the flame produced by the ignited metal wick 11, thus achieving the effect of automatic fuel replenishment. More notably, the metal wick 11 heats up due to heat conduction when ignited. Replenishing it with room-temperature propylene glycol-based liquid fuel from the second fuel tank 20 can cool the metal wick 11, achieving a cooling effect.

[0046] The operation of the combustion device may also include the following steps:

[0047] The drive unit 40 also receives a shutdown signal, which is used to draw propylene glycol-based liquid fuel in the first fuel tank 10 to the second fuel tank 20 through the pipeline 30 until the propylene glycol-based liquid fuel in the first fuel tank 10 reaches a low level so that the metal wick 11 cannot produce a flame, or to completely draw propylene glycol-based liquid fuel in the first fuel tank 10 to the second fuel tank 20 so that the flame at the end of the metal wick 11 is extinguished.

[0048] The drive unit 40 receives a shutdown signal and pumps the level of propylene glycol-based liquid fuel in the first fuel tank 10 to a low level, or pumps the propylene glycol-based liquid fuel in the first fuel tank 10 completely into the second fuel tank 20 (as sensed by the sensing unit 12) and continues to operate for a predetermined time, thereby delaying the shutdown of the drive unit 40 to extract the exhaust gas generated by the flame extinguishing at the end of the metal wick 11 via the pipeline 30.

[0049] Based on the above, in the embodiments of the present invention, the drive unit 40 is configured to receive a refueling signal from the sensing unit 12, thereby replenishing the first fuel tank 10 with propylene glycol-based liquid fuel from the second fuel tank 20 via the pipeline 30, achieving the effect of automatically replenishing fuel and cooling the metal wick 11. Furthermore, the drive unit 40 is also configured to receive a shut-off signal, thereby drawing the propylene glycol-based liquid fuel from the first fuel tank 10 to the second fuel tank 20 via the pipeline 30, effectively extinguishing the flame and reducing temperature. Further, the drive unit 40 is configured to continue operating for a predetermined time after receiving the shut-off signal and drawing the propylene glycol-based liquid fuel from the first fuel tank 10 to the second fuel tank 20, thereby removing the exhaust gas generated by the extinguishing of the flame at the tip of the metal wick 11.

[0050] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the claims.

Claims

1. A combustion device using at least 90 wt% propylene glycol-based liquid fuel, characterized in that, The combustion device includes: A first fuel tank is provided for containing the propylene glycol-based liquid fuel and a metal wick for transmitting the propylene glycol-based liquid fuel is inserted therein. A sensing unit is provided in the first fuel tank. The sensing unit is configured to receive a start signal and sense the liquid level of the propylene glycol-based liquid fuel in the first fuel tank, thereby issuing a refueling signal. A second fuel tank for containing the propylene glycol-based liquid fuel; A pipeline connecting the first fuel tank and the second fuel tank; and A drive unit is disposed on the pipeline and is configured to receive the refueling signal, thereby replenishing the propylene glycol-based liquid fuel in the second fuel tank to the first fuel tank via the pipeline, and cooling the metal wick with the propylene glycol-based liquid fuel from the second fuel tank. The drive unit is also configured to receive a shut-off signal, thereby drawing the propylene glycol-based liquid fuel in the first fuel tank to the second fuel tank via the pipeline.

2. The combustion device as described in claim 1, characterized in that, The drive unit is configured to receive the shutdown signal and continue operating for a predetermined time after transferring the propylene glycol-based liquid fuel from the first fuel tank to the second fuel tank.

3. The combustion device as described in claim 1, characterized in that, The volume of the first fuel tank is smaller than the volume of the second fuel tank.

4. The combustion device as described in claim 3, characterized in that, The volume of the second fuel tank is more than ten times that of the first fuel tank.

5. The combustion device as described in claim 1, characterized in that, This propylene glycol-based liquid fuel contains 95 wt% propylene glycol.

6. The combustion device as claimed in claim 1, characterized in that, The pipeline includes a first pipe section connecting the first fuel tank and the drive unit, and a second pipe section connecting the drive unit and the second fuel tank.

7. The combustion device as claimed in claim 1, characterized in that, The drive unit includes a motor.

8. A method for operating a combustion device, characterized in that, The combustion device uses at least 90 wt% propylene glycol-based liquid fuel and includes: A first fuel tank is provided for holding the propylene glycol-based liquid fuel and a metal wick for transmitting the propylene glycol-based liquid fuel is inserted therein. A sensing unit is provided inside the first fuel tank. A second fuel tank for containing the propylene glycol-based liquid fuel; A pipeline connecting the first fuel tank and the second fuel tank; and A drive unit is installed on this pipeline; The operation method of the combustion device includes the following steps: the sensing unit receives a start signal and senses the liquid level of the propylene glycol-based liquid fuel in the first fuel tank, thereby issuing a fuel replenishment signal; the drive unit receives the fuel replenishment signal and replenishes the propylene glycol-based liquid fuel in the second fuel tank to the first fuel tank via the pipeline, and cools the metal wick with the propylene glycol-based liquid fuel from the second fuel tank; the drive unit also receives a shut-off signal and draws the propylene glycol-based liquid fuel in the first fuel tank to the second fuel tank via the pipeline; after receiving the shut-off signal and drawing the propylene glycol-based liquid fuel in the first fuel tank to the second fuel tank, the drive unit continues to operate for a predetermined time, thereby delaying the shutdown of the drive unit to remove exhaust gas.

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