JP2008145051A - Liquid fuel combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid fuel combustion device, preventing malfunction of a temperature sensor due to opening failure of a return valve, and preventing leakage due to a decrease in resin-part dimension of a connecting part. <P>SOLUTION: Although high-temperature fuel leaking from a carburetor 15 due to "opening failure" of the return valve 26 flows through a return pipeline 23 toward a tank part 12 during combustion, the return pipeline 23 is made to substantially closely adhere to an outgoing pipeline 21 where low-temperature fuel sent from the tank part 12 passes by a fixture 61, whereby the temperature of the return pipeline 23 is caused to drop by heat exchange, and the temperature of the fuel itself leaking from the carburetor 15 is also caused to drop. Thus, the temperature of fuel flowing in the resin-made part of a fuel circulation connecting part 47 drops, so that "thinning" phenomenon of the resin part can be prevented to hardly cause fuel leakage from the connecting part 47. As a result, the safety as the liquid fuel combustion device is improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid fuel combustion apparatus such as an oil fan heater.

  Conventionally, an oil fan heater has been widely used in general households as one of liquid fuel combustion apparatuses. FIG. 6 shows the appearance of a conventional general oil fan heater. The outline of the oil fan heater will be described with reference to FIG. In such an oil fan heater, a combustion section and a fuel tank as a liquid supply device are housed in a housing 1.

  The housing 1 is a box-shaped member composed of a front plate 6 that covers the front surface, a side back plate 7 that covers the side surface and the back surface, and an upper plate 8 that covers the top surface. It is placed. At the lower part of the front plate 6, an air outlet 2 for blowing warm air into the room is formed. On the upper part of the front plate 6, an operation unit 3 in which switches for switching the operation state are accommodated is arranged. The upper plate 8 is provided with a take-out port for the liquid supply device, and the main body lid 4 is disposed at the take-out port so as to be freely opened and closed.

  In such an oil fan heater, an oil fan heater as shown in FIG. 7 has already been put into practical use as a type that can be easily replenished. FIG. 7 is a perspective view showing the oil fan heater shown in FIG. 6 with the tank taken out from the housing 1.

  In the oil fan heater shown in FIG. 7, since fuel is taken out from the upper side rather than the lower side of the tank section 12, the structure of the fuel circulation inside the casing 1 of the oil fan heater is schematically shown in FIG. The structure shown is proposed. Inside the casing 1 of the oil fan heater, in addition to the tank portion 12 for storing fuel such as kerosene, an electromagnetic pump 14 serving as a drive source for sending fuel, and vaporization for heating and vaporizing the fuel The container 15 and the combustion part 16 for mixing and burning the gas produced by vaporizing the fuel with air are accommodated. The fuel circulation connecting portion 47 and the electromagnetic pump 14 are connected by an outward piping 21, and the electromagnetic pump 14 and the vaporizer 15 are connected by an outward piping 22. A nozzle 31 protrudes from the vaporizer 15 to the combustion unit 16, and the nozzle 31 can be opened and closed. A return pipe 23 for returning fuel to the tank unit 12 is connected to the vaporizer 15. Note that the outgoing pipes 21 and 22 and the return pipe 23 are both made of metal.

  A connection point between the vaporizer 15 and the return pipe 23 can be opened and closed by a return valve 26. A more detailed structure near the vaporizer 15 is shown in FIG. The nozzle 31 and the return valve 26 are configured to open and close by moving the common needle 32 back and forth by electromagnetic control inside the vaporizer 15. The front end of the carburetor 15 is a nozzle 31, and when not energized, the tip of the needle 32 is inserted and the nozzle 31 is closed, but when the needle 32 is retracted (when moved to the right side in FIG. 10). ), The nozzle 31 opens when the tip of the needle 32 leaves. At the same time, the O-ring 26a fitted to the slightly thickened portion on the rear side of the needle 32 closes the outlet on the rear side of the vaporizer 15, thereby closing the return valve 26. On the contrary, when the needle 32 moves forward (when it moves to the left side in FIG. 10), the tip of the needle 32 is inserted, the nozzle 31 is closed, and the return valve 26 is opened. That is, the open / closed states of the nozzle 31 and the return valve 26 are linked to each other. When the nozzle 31 is opened, the return valve 26 is closed, and when the nozzle 31 is closed, the return valve 26 is opened.

  The combustion circulation connecting portion 47 connected to the tank portion 12 is provided with a tube for taking out fuel from the tank portion 12 and a tube for returning surplus fuel to the tank portion 12. As shown in FIGS. 7 and 8, the combustion circulation connecting portion 47 includes a tank side connecting portion 48 attached to the tank portion 12 and a main body side connecting portion 49 attached to the oil fan heater main body side. . These are mainly composed of parts molded of resin. The tank side connection portion 48 includes a first connector 48 a for taking out from the tank portion 12 and a second connector 48 b for returning surplus fuel to the tank portion 12. By connecting the tank side connection portion 48 and the main body side connection portion 49 to each other, fuel circulation is achieved between the tank portion 12 and the oil fan heater main body. The main body side connection portion 49 includes a double passage portion 96 that forms an inverted U-shaped passage. An air valve 25 for opening and closing the internal space of the double passage portion 96 with respect to the outside air is provided on the upper portion of the double passage portion 96. The air valve 25 is of a type that opens and closes by moving an internal valve body by electromagnetic control, and is closed when not energized and opened when energized.

[Start of normal operation]
An example of the operation procedure when normal operation is started in this oil fan heater will be described with reference to FIG. When normal operation is started, the electromagnetic pump 14 is activated. At this point, the nozzle 31 is closed, the return valve 26 is open, and the air valve 25 is open. The electromagnetic pump 14 that has started to operate tries to draw fuel through the forward piping 21. Thereafter, the air valve 25 is closed. As a result, the double passage portion 96 is kept airtight, and the electromagnetic pump 14 can continuously take out fuel from the tank portion 12 through the outward piping 21. By the operation of the electromagnetic pump 14, the fuel is sent to the carburetor 15 through the outgoing pipes 21 and 22. In the carburetor 15, the fuel is heated by a heater (not shown) to a temperature θ 1 that is equal to or higher than the fuel evaporation temperature and is vaporized. Since the nozzle 31 is closed, the inside of the vaporizer 15 becomes a high pressure, but the return valve 26 is open, so that excess pressure can escape to the return pipe 23 through the return valve 26. If fuel remains in the return pipe 23 due to normal operation before that, the fuel is pushed back to the tank portion 12.

  After heating the vaporizer 15 for a certain period of time and vaporizing a sufficient amount of fuel for ignition, the nozzle 31 is opened. At the same time, the return valve 26 is closed. Vaporized fuel (hereinafter referred to as “vaporized fuel”) is sent from the nozzle 31 to the combustion unit 16 and ignited by an ignition heater (not shown) provided in the combustion unit 16 to start combustion. This liquid fuel combustion apparatus is provided with a blower fan (not shown) for sucking and sending outside air. The air taken in from the outside by the sending fan receives the heat generated in the combustion section 16 to become warm air, and is sent out from the blowout port 2 (see FIG. 3) to heat the oil fan heater. Hereinafter, the fuel is supplied into the carburetor 15 by the electromagnetic pump 14, the fuel is vaporized by being heated to the temperature θ <b> 1 in the carburetor 15, and the vaporized fuel is supplied to the combustion unit 16 through the nozzle 31. By this, combustion is continued.

[Stop normal operation]
When the normal operation is stopped, the electromagnetic pump 14 is stopped and the air valve 25 is opened, whereby the new supply to the vaporizer 15 is stopped. On the other hand, after that, the nozzle 31 is open for a predetermined time, and the combustion in the combustion section 16 is continued for a predetermined time. By this combustion, much of the vaporized fuel remaining in the vaporizer 15 is consumed. Thereafter, the return valve 26 is opened by closing the nozzle 31. Since the inside of the carburetor 15 is at high temperature and high pressure, if the return valve 26 is opened, only a part of the vaporized fuel remaining in the carburetor 15 without being burned is pushed by the pressure in the carburetor 15, and the return pipe 23 Get in.

The vaporized fuel that has entered the return pipe 23 may remain as it is, but is pushed back toward the tank unit 12 at the start of the next normal operation.
Hereinafter, the “open failure” refers to a failure in which a part or all of the passage is left open without being sufficiently sealed when an attempt is made to close the valve.

[Open valve failure]
As described above, in normal operation, fuel is supplied from the residential pipe 22 into the carburetor 15. The fuel supply from the dwelling line pipe 22 is based on the premise that the return valve 26 is closed except at the beginning of operation. The reason for this is that during normal operation, the inside of the carburetor 15 becomes hot and high pressure, so if the return valve 26 is not closed, high-temperature fuel is pushed out to the return pipe 23 by the pressure in the carburetor 15. There is to be.

  However, it cannot be said that there is no possibility that the return valve 26 will fail. If the return valve 26 fails to open during normal operation, the high-temperature fuel pushed out by the pressure in the carburetor 15 passes through the return pipe 23 and the fuel circulation connection portion. 47 to the tank section 12. Since the main part of the fuel circulation connection part 47 is made of resin, when high-temperature fuel gas flows to the vicinity of the fuel circulation connection part 47, the resin part of the fuel circulation connection part 47 may be melted and deformed.

  Patent Document 1 discloses a liquid fuel combustion apparatus in which a temperature sensor is attached to a connection portion. FIG. 9 is a diagram showing an example of such a liquid fuel combustion apparatus. This liquid fuel combustion apparatus includes a tank unit 12 for holding liquid fuel, a vaporizer 15 for heating and vaporizing the liquid fuel sent to the inside, and the tank unit 12 toward the vaporizer 15. Outbound piping 21 for sending liquid fuel, return piping 23 for returning liquid fuel from the vaporizer 15 to the tank portion 12, and resin parts for connecting the outbound piping 21 and the returning piping 23 to the tank portion 12. And a temperature sensor 160 disposed so as to detect the temperature of the return pipe 23. A specific configuration example in the vicinity of the temperature sensor 160 is shown in the perspective view of FIG. By adopting this configuration, if the high-temperature fuel heated by the carburetor 15 leaks to the return pipe 23 due to some failure, the temperature of the return pipe 23 rises, so that it can be detected by the temperature sensor 160. .

  However, this liquid fuel combustion apparatus includes the following problems. That is, when the high-temperature fuel heated by the carburetor 15 leaks into the return pipe 23, the temperature of the return pipe 23 rises. Therefore, this temperature increase can be detected by the temperature sensor 160. The fuel at a high temperature flows into the connecting portion 47 including the resin parts for connecting the forward piping 22 and the backward piping 23. In order to prevent this, it is conceivable that the operating temperature at which the temperature sensor 160 is detected and operated as a safety device is set low. However, if the operating temperature is set strictly, malfunctioning may occur and alarm notification or operation may occur even during normal combustion. Stops occur frequently, making usability worse. For example, if the air volume decreases due to dust or the like adhering to the air intake port, the temperature in the appliance rises, the temperature of the temperature sensor mounting portion 161 rises, and it is not an “open failure” of the return valve 26. There is a possibility that the temperature sensor 160 is activated.

If the operating temperature is set high in order to prevent malfunction of the temperature sensor 160, the return valve 26 can be used for a long time in an “open failure” state even if the resin part of the connecting portion 47 is not deformed. Then, the resin parts are softened by the inflow of the high-temperature fuel, and the phenomenon that the softened resin parts are “fainted” by the flow of the fuel occurs, and the dimensions of the resin parts are reduced. As a result, a gap is generated in the connecting portion 47, and fuel leaking from the return valve 26 of the carburetor 15 may leak out through this gap portion. Such fuel leaks not only cause safety problems, but also cause unpleasant odors during combustion.
JP 2003-21328 A

  Considering the above situation, it is necessary to take measures to prevent such an accident caused by the open valve failure. Accordingly, it is an object of the present invention to pay attention to the forward piping through which the fuel having a low oil temperature flows, and to cool the backward piping using the forward piping.

  An object of the present invention is to provide a liquid fuel combustion apparatus in which such a temperature sensor due to an open failure of a return valve does not malfunction, and leakage due to a reduction in the size of a resin part in a connection portion can be eliminated. It is to be.

  In order to solve the above-described problems and achieve the object, a liquid fuel combustion apparatus according to the present invention includes a tank unit for holding liquid fuel, and a vaporizer for heating and vaporizing the liquid fuel sent to the inside. A forward pipe for sending liquid fuel from the tank part toward the vaporizer, a return pipe for returning liquid fuel from the vaporizer to the tank part, and the forward pipe and the return path to the tank part A connecting portion for connecting a pipe, and an attachment for closely contacting the forward pipe and the return pipe for cooling the return pipe.

  By adopting this configuration, during combustion, high-temperature fuel leaked from the carburetor due to the "open failure" of the return valve flows to the tank part through the return pipe, but the return pipe is sent from the tank part. By being in close contact with the outward piping through which the low-temperature fuel passes, the temperature of the return piping decreases due to heat exchange, and thus the temperature of the fuel itself leaking from the vaporizer also decreases. As a result, the temperature of the fuel flowing into the resin part at the connecting portion is lowered, so that the phenomenon of “leaning” of the resin portion can be prevented and the fuel leakage from the connecting portion is less likely to occur. As a result, the safety as a liquid fuel combustion apparatus is improved.

  In the liquid fuel combustion apparatus, the temperature sensor can be disposed between the fitting for the return pipe and the vaporizer. As a result, the fuel leaking from the vaporizer is detected at a high temperature (before being cooled) by the temperature sensor, so that a high-temperature fuel leak can be detected more reliably. The leaked fuel is cooled by the fixture after passing through the temperature sensor mounting part, so the temperature at the connection part including the resin part is low, which is caused by the “skinning” of the resin part as described above. Fuel leakage from the connected part is prevented.

  In the liquid fuel combustion apparatus in which the temperature sensor is arranged, preferably, the temperature sensor can be attached to the vaporizer side of a fixture. As a result, it is not necessary to use a separate attachment for attaching the temperature sensor to the return pipe, and the number of assembling steps is reduced, so that an increase in cost can be suppressed.

  In the liquid fuel combustion apparatus in which the temperature sensor operates at a temperature equal to or higher than a predetermined temperature, the predetermined temperature at which the notification and operation stop function is activated by the temperature sensor can be set so as to change according to the temperature detected by the room temperature sensor. . That is, the predetermined temperature when the room temperature is low is set lower than the predetermined temperature when the room temperature is high. As a result, malfunctions related to the notification and operation stop functions are reduced.

  According to the liquid fuel combustion apparatus of the present invention, if the return valve has an open failure, the temperature of the return pipe rises due to the high-temperature fuel heated by the carburetor. it can. At this time, since the return piping is effectively cooled by contact with the outward piping, the oil temperature at the connecting portion is greatly reduced, and the deformation of the resin parts at the connecting portion with the tank portion is not only avoided. In addition, “skinning” of resin parts can be prevented.

[Embodiment 1]
A liquid fuel combustion apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 3 is a front view showing a close contact state between the return piping and the outward piping according to the attachment diagram, FIG. 4 (a) is a sectional view taken along line AA in FIG. 3, and FIG. 4 (b) is a sectional view taken along line BB in FIG. FIG. This liquid fuel combustion apparatus is basically the same as that shown in FIG. 9 except that the return pipe 23 is arranged in part in parallel with the forward pipe 21 in order to ensure that both are in contact with each other. These are attached between the main body side connection portion 49 of the fuel circulation connection portion 47 and the carburetor 15 by a plurality of attachment tools 61 (two in this example, but not limited thereto). A temperature sensor 160 is attached to the return pipe 23 between the attachment 61 and the vaporizer 15 by a sensor attachment 62.

  As shown in enlarged views in FIGS. 3 and 4A, the attachment by the attachment tool is performed by bending the attachment tool 61 so as to wrap both the pipes 21 and 23 and causing plastic deformation so as not to return elastically. It has been broken. Also in the case of attachment in the case of the attachment 62, as shown in an enlarged view in FIGS. 3 and 4 (b), as in the case of the attachment 61, both the pipes 21, 23 and the temperature sensor 160 should be wrapped together. It is performed by bending it into plastic deformation. In this example, the temperature sensor is composed of, for example, a thermistor. In this example, the temperature sensor 160 is attached so as to be held by the nail of the attachment 64, but may be attached by screwing or the like. In this case, it is desirable that the fixture 61 is made of metal having excellent thermal conductivity. By making the attachment 61 made of metal, the temperature of the return pipe can be lowered more effectively by heat exchange with the outward pipe and heat radiation from the attachment.

[Embodiment 2]
A second embodiment of the liquid fuel combustion apparatus according to the present invention will be described with reference to FIG. This liquid fuel combustion apparatus is basically the same as that shown in FIG. 1, but a temperature sensor 160 is integrally attached to the attachment 64. It is desirable that the attachment position of the temperature sensor 160 to the attachment tool 64 is on the vaporizer 15 side of the attachment tool 64. Further, the temperature sensor 160 is attached to the return pipe 23 side in the attachment 64. Thus, by attaching the temperature sensor 160 to the carburetor 15 side, it is possible to detect the temperature of the return pipe 23 before cooling, and therefore more reliably leakage due to the “open failure” of the return valve 26 of the carburetor 15. Further, since the sensor attachment 62 is not necessary, workability is improved and an increase in cost is suppressed.

  The liquid fuel combustion apparatus includes a control unit (not shown) for controlling the operation of the entire apparatus. In the control unit, when the temperature sensor 160 detects an abnormally high temperature such as a predetermined temperature or more, the operation is stopped, and a notification that an abnormality has occurred is displayed to the user. A room temperature thermistor as a room temperature sensor (detection means) is disposed (not shown) in the housing 1 of the instrument. The control unit compares the detected value of the temperature sensor 160 with the detected value of the room temperature thermistor, and if the difference is greater than or equal to a predetermined value, activates one or both of the notification or the liquid fuel combustion device shutdown function. Let As a result, the operation can be stopped when an abnormality occurs, so it is possible to avoid accidents such as melting of resin parts and exhaust of vaporized fuel to the outside, and reducing malfunctions of notification and operation stop functions. To do.

[Action / Effect]
In the above-described liquid fuel combustion apparatus, when normal operation is performed, if the return valve 26 has an open failure, the high-temperature fuel heated by the carburetor 15 is pushed out to the return pipe 23. In that case, since the temperature of the return pipe 23 increases, the temperature sensor 160 can detect a high-temperature fuel leak from the carburetor 15. The return pipe 23 is made of metal, and in a part of the section from the return valve 26 to the fuel circulation connection portion 47, it is also arranged in parallel with the metal outgoing pipe 22. In order to make contact, both pipes are attached between the main body side connection part 49 of the fuel circulation connection part 47 and the carburetor 15 by means of attachments 61 and 64. With this arrangement, the return pipe 23 is in close contact with the forward pipe 21 connected to the tank unit 12, so that the vaporizer is caused by the “open failure” of the return valve 26 of the vaporizer 15. When the high temperature fuel leaks from 15 to the return pipe 23, the temperature of the return pipe 23 through which the high temperature fuel flows decreases due to heat exchange with the forward pipe 21 through which the low temperature fuel flows. The temperature of the fuel itself will also decrease. As a result, the temperature of the fuel flowing into the resin part of the connection part 47 is lowered, so that the phenomenon of “skinning” of the resin part can be prevented and the fuel leakage from the connection part 47 is less likely to occur. Improves.

  Thus, when the temperature sensor 160 detects the high temperature of the fuel, the control unit immediately stops the operation and displays that the abnormality has occurred to the user. When the control unit stops the operation, the heating of the vaporizer 15 and the supply of fuel by the electromagnetic pump 14 are stopped, so that the flow of high-temperature fuel toward the fuel circulation connection unit 47 through the return pipe 23 is also stopped. . Even immediately before the control unit stops the operation, the temperature of the fuel leaking from the vaporizer 15 is sufficiently lowered by passing through the fittings 61 and 64. As a result, it is possible to avoid a situation in which the resin part of the fuel circulation connecting portion 47 is blurred.

  As a method of attaching the temperature sensor 160, in addition to the attachment by the sensor attachment 62 and the integral attachment to the attachment 64, any other attachment method can be used as long as the temperature of the return pipe 23 can be monitored. It may be. The temperature sensor may be of a type other than the thermistor.

The material of the attachment 61 is preferably copper or aluminum having good thermal conductivity among metals, but galvanized steel sheets, aluminum plated steel sheets, etc. may be used in consideration of price. A plurality of fins 63 as shown in FIG. However, the shape is not limited to the fin 63 or the like, and other shapes may be used as long as heat dissipation is good.
By providing the attachment 61 with heat radiating means such as the fins 63, the temperature of the return pipe 23 is further lowered, and the temperature of the fuel flowing into the connecting portion is further lowered. It is also possible to prevent fuel leakage from the connecting portion.

上表のように、本実施例のように取り付け具をつけることにより、接続部油温は６５℃から５０℃に下がる。 In the following, the relationship between the temperature of the temperature sensor 160 according to the present invention, the oil temperature of the connecting portion 47 and the amount of leakage when a “open failure” of the return valve 26 of the carburetor 15 occurs and a comparison with the prior art embodiment will be shown. .

As shown in the above table, the attachment oil temperature is lowered from 65 ° C. to 50 ° C. by attaching the fixture as in this embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a piping structure conceptual diagram in Embodiment 1 of the liquid fuel combustion apparatus by this invention. It is an arrangement configuration conceptual diagram in Embodiment 2 of a liquid fuel combustion device by the present invention. It is a front view of the fixture of Embodiment 2 shown in FIG. It is sectional drawing which shows the relationship between the fixture of Embodiment 2 shown in FIG. 2, an outward piping, a return piping, and a temperature sensor. It is a perspective view of the fixture with the thermal radiation means of the liquid fuel combustion apparatus by this invention. It is a perspective view of the conventional common liquid fuel combustion apparatus. It is explanatory drawing of a mode that the tank part of the liquid fuel combustion apparatus by a prior art is attached or detached. It is a conceptual diagram of the piping structure of the liquid fuel combustion apparatus by a prior art. It is a conceptual diagram of the piping structure which attached the temperature sensor of the liquid fuel combustion apparatus by a prior art. It is sectional drawing of the vaporizer vicinity of the liquid fuel combustion apparatus by a prior art. It is the perspective view which attached the temperature sensor of the liquid fuel combustion apparatus based on a prior art to the connection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Air outlet 3 Operation part 4 Main body cover 5 Stand 6 Front plate 7 Side back plate 8 Upper plate 12 Tank part 14 Electromagnetic pump 15 Vaporizer 16 Combustion parts 21, 22 Outgoing piping 23 Return piping 24, 44 Supply port 25 Air valve 26 Return valve 26a (Ring valve) O-ring 31 Nozzle 32 Needle 47 Fuel circulation connection portion 48 Tank side connection portion 48a First connector 48b Second connector 49 Main body side connection portions 61, 64 Attachment 62 Sensor Attachment 63 Fin 96 Double passage part 160 Temperature sensor 161 Temperature sensor attachment part

Claims (4)

  A tank unit for holding liquid fuel, a vaporizer for heating and vaporizing the liquid fuel sent into the interior, and an outward piping for sending the liquid fuel from the tank unit toward the vaporizer A return pipe for returning liquid fuel from the vaporizer to the tank part, and a connection part for connecting the forward pipe and the return pipe to the tank part, and for cooling the return pipe A liquid fuel combustion apparatus comprising an attachment for closely contacting an outward piping and the backward piping.   The liquid fuel combustion apparatus according to claim 1, wherein a temperature sensor that detects a temperature of the return pipe is installed between the attachment and the vaporizer.   The liquid fuel combustion apparatus according to claim 2, wherein the temperature sensor is attached to the carburetor side of the attachment.   The liquid fuel combustion apparatus according to claim 2 or 3, wherein the predetermined temperature at which the temperature sensor operates varies depending on the temperature detected by the room temperature sensor.

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