JP4252585B2 - Fire alarm - Google Patents

Description

  The present invention relates to a fire alarm.

  In recent years, as the nuclear family and the declining birthrate have progressed, the number of elderly households has increased mainly in the suburbs of the city, and when a fire breaks out while the elderly are sleeping, the elderly are late and burnt down. There are many painful cases. In response to this situation, each local government has enacted regulations and made it mandatory to install fire alarms in ordinary households. As an example, the Tokyo Metropolitan Government requires that new houses be equipped with fire alarms in each room in accordance with the Fire Prevention Ordinance that came into effect on October 1, 2004.

A general fire alarm currently on the market is either one connected to a commercial power source of 100 V or one driven by a dry battery (see, for example, Patent Document 1).
JP 2006-059278 A (Claim 7 etc.)

  However, in the case of a type of fire alarm connected to a 100V commercial power supply, it will not function during a power failure. On the other hand, in the case of a fire alarm of a type driven by a dry battery, it does not function when the dry battery is exhausted. For this reason, if a fire occurs accidentally at the time of a power failure or when the dry battery is exhausted, there is a risk that the fire alarm will not be driven.

  An object of the present invention is to solve the above problem, that is, to provide a highly reliable fire alarm device without depending on the supply of electric power from an external power source.

In order to achieve the above object, the present invention comprises a Peltier element and an alarm output means that is supplied with electric power from the Peltier element, a metal substrate having a larger area than the cooling surface is brought into contact with the cooling surface of the Peltier element, A metal substrate exposed around the Peltier element is covered with a heat shield member made of a material having a thermal conductivity lower than that of the metal substrate, and the heat shield member is a box having a space between the metal substrate and the metal substrate. A fire alarm device having a shape and storing alarm output means and a lead wire connecting the alarm output means and the Peltier element in the space.

  The Peltier element is an element that generates a temperature difference between the front and back when a voltage is applied to the element, and is often used for temperature control by adjusting the voltage. For example, as the density of electronic circuit boards increases, the temperature in various electronic control boxes on which the electronic circuit boards are mounted rises to a considerably high temperature due to heat generated by the operation of the electronic components. If this is left unattended, it will lead to failure of electronic components, so the Peltier element is used for cooling. The action opposite to that of the Peltier element, that is, the action of generating an electromotive force by applying a temperature difference is known as the Seebeck effect. When a temperature difference is applied between the front surface and the back surface of the Peltier element, the Peltier element generates an electromotive force by an action opposite to its original action. Using this principle to construct a fire alarm equipped with a Peltier element, an electromotive force is generated due to the temperature difference between the surface exposed to the heat generated by the fire and the other surface that avoids the radiation of the heat. An alarm can be output from the alarm output means driven by the. The alarm can be sound, light, or both.

In another invention, the upper surface of the heat shielding member is configured to be lower than the upper surface of the Peltier element in the previous invention .

In another aspect of the invention, the fire alarm is provided with a hole in the outer surface of the heat shielding member.

  Another invention is a fire alarm device in which the heating surface of the Peltier element is painted black in each of the previous inventions. For this reason, in the process by which a heating surface is heated by a fire, the endothermic effect of a heating surface can be heightened, and the temperature difference between a cooling surface and a heating surface can be large and can be maintained for a long time.

  According to the present invention, a highly reliable fire alarm can be provided regardless of the supply of power from an external power source.

  Hereinafter, a preferred embodiment of a fire alarm according to the present invention will be described with reference to the drawings. In the following description, the upward direction and downward direction of each drawing are referred to as “upper” and “lower”, respectively. Note that the present invention is not limited to the preferred embodiments described below.

  FIG. 1 is a perspective view of a fire alarm device 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the fire alarm device 1 shown in FIG.

  The fire alarm device 1 has a shape of a regular quadrangular column having a smaller thickness than each side of the bottom surface. A square recess 2 is provided at the approximate center of the top surface of the fire alarm 1 shown in FIG. A square metal substrate 3 larger than the recess 2 is provided below the fire alarm 1. The metal substrate 3 is an aluminum plate. Above the metal substrate 3, a Peltier element 4 is provided at the position of the recess 2, and a heat shielding member 5 is provided around the Peltier element 4. A black coating is applied to the upper surface of the Peltier element 4 shown in FIG. The heat shielding member 5 is made of a stainless steel plate.

  The Peltier element 4 is fixed to the metal substrate 3 so that its lower surface shown in FIG. 2 is in contact with the upper surface of the metal substrate 3. The heat shielding member 5 is open on the metal substrate 3 side, and is fixed on the metal substrate 3 so that the opening end thereof is in contact with the metal substrate 3. The space 6 formed between the heat shielding member 5 and the metal substrate 3 is an example of a lead wire 7 drawn from the Peltier element 4 and an alarm output means electrically connected to the lead wire 7. A buzzer 8 is arranged. The lead wire 7 is a conducting wire made of a material that does not easily increase in electrical resistance even when the temperature becomes high. A hole 9 is formed in the outer surface of the heat shielding member 5. If the hole 9 is formed in the outer surface of the heat shielding member 5, heat is not easily transmitted from the hole 9 to the internal space 6, and the lead wire 7 and the buzzer 8 can be protected from heat.

  As shown in the enlarged view of a part (X) of the Peltier element 4, the Peltier element 4 includes a plurality of electrodes 12 and a plurality of electrodes on the inner side of each of two substrates (heating surfaces) 10 and a substrate (cooling surface) 11. The electrode 13 is provided. The plurality of electrodes 12 are fixed to the inner surface of the substrate 10 with a predetermined interval. The plurality of electrodes 13 are also fixed to the inner surface of the substrate 11 at a predetermined interval. The distance between the electrodes 12 and the distance between the electrodes 13 are provided so as not to line up with each other in the vertical direction. The electrode 12 and the electrode 13 sandwich the P-type semiconductor 14 and the N-type semiconductor 15 alternately.

  When heat is applied to the substrate 10 and a temperature gradient is generated between the substrate 10 and the substrate 11, electrons flow from the electrode 12 to the P-type semiconductor 14, and electrons flow from the P-type semiconductor 14 to the electrode 13. Electrons flow from the electrode 13 to the N-type semiconductor 15 and from the N-type semiconductor 15 to the electrode 12. Thus, when electrons flow in the order of the electrode 12, the P-type semiconductor 14, the electrode 13, and the N-type semiconductor 15, a voltage can be applied to the buzzer 8 that is electrically connected to the Peltier element 4. The efficiency with which the Peltier element 4 generates electricity increases as the heat flow rate through the element 4 increases. The electric power of the Peltier element 4 is proportional to the square of the temperature difference between the heating surface and the cooling surface. For this reason, it is important to devise a temperature gradient between the heating surface and the cooling surface as large as possible.

  Since the metal substrate 3 is made of aluminum having a relatively high thermal conductivity among metals, even if heat is applied to the Peltier element 4 from above in FIG. 2, the substrate 11 of the Peltier element 4 is easily dissipated. Easy to keep low temperature. The heat shielding member 5 is made of a stainless steel metal having a lower thermal conductivity than the metal substrate 3. For this reason, heat transfer to the metal substrate 3 can be effectively prevented. Further, since the substrate 10 on the upper surface side of the Peltier element 4 is painted black, if a fire occurs on the substrate 10 side of the Peltier element 4, the heat absorption on the substrate 10 side of the Peltier element 4 increases, The temperature gradient between 10 and the substrate 11 can be increased.

  FIG. 3 is a cross-sectional view of Modification 1 of the fire alarm device 1 shown in FIG. 1 taken along the line AA shown in FIG.

  As shown in FIG. 3, a metal substrate 3 may be provided below the fire alarm device 1, and a number of irregularities 20 may be formed below the metal substrate 3. If the unevenness 20 is formed below the metal substrate 3, the surface area of the metal substrate 3 can be increased, and the heat dissipation can be further improved. Further, a hole 21 for outputting the sound of the buzzer 8 to the outside is provided on the upper surface of the heat shielding member 5. However, the hole 21 is preferably small in order to make it difficult to transfer external heat to the space 6.

  FIG. 4 is a perspective view showing a second modification of the fire alarm device 1 shown in FIG.

  As shown in FIG. 4, the lead wire 7 may be pulled out from the main body of the fire alarm 1 and the buzzer 8 may be separated from the main body. Thereby, the main body and the buzzer 8 can be separately installed at a place where heat is detected and a place where an alarm is output. Thereby, the danger that the buzzer 8 will be damaged by heat can be reduced, and a fire can be immediately warned to a sleeping resident.

  FIG. 5 is a perspective view showing a third modification of the fire alarm device 1 shown in FIG. FIG. 6 is a cross-sectional view of the fire alarm device 1 shown in FIG.

  As shown in FIG. 5 and FIG. 6, the fire alarm device 1 may have a convex portion 30 from which the Peltier element 4 protrudes with the upper surface of the heat shielding member 5 positioned below the upper surface of the Peltier element 4. Moreover, you may employ | adopt the fire alarm 1 which does not provide the hole for outputting the sound of the buzzer 8 outside like the modification 3. FIG.

  In the above-described embodiment, the Peltier element 4 serves as a power supply means sufficient to generate power by the heat of the flame and sound the buzzer 8 when a fire occurs. For this reason, the fire alarm 1 can perform a fire detection and an alarm. Such a function of the fire alarm 1 is realized without an external power source such as a commercial power source or a dry battery. Since the constituent material of the Peltier element 4 is a chemically very stable compound or alloy, the function of the fire alarm device 1 hardly deteriorates with time.

  Since the Peltier device 4 can generate enough power to sound the buzzer 8 in a temperature environment of 100 ° C. or less and can continue power generation even at a temperature exceeding 200 ° C., the power source of the fire alarm 1 Is suitable. The fire alarm 1 can detect an abnormal heat and output an alarm more quickly as the installation location of the fire alarm 1 is closer to the stove that is the main cause of the fire.

  FIG. 7 is a front view showing a modified example 4 of the fire alarm 1 shown in FIG. FIG. 8 is a view in which only the Peltier element 4 and the metal substrate 3 of the fire alarm device 1 shown in FIG. 7 are taken out and viewed from the bottom surface side of the metal substrate 3.

  The fire alarm device 1 shown in FIGS. 7 and 8 includes a buzzer 8 inside thereof, and has a configuration in which a metal substrate 3 smaller than the area is fixed to the cooling surface of the Peltier element 4. The metal substrate 3, the lead wire 7 and the buzzer 8 are surrounded by the heat shielding member 5. A hole 9 for outputting the sound of the buzzer 8 is provided on the side surface of the heat shielding member 5. Further, the Peltier element 4 is exposed on the surface of the fire alarm device 1 without being surrounded by the heat shielding member 5 on the heating surface side.

The area of the cooling surface of the Peltier element 4 is A × B. The area of the contact surface with the Peltier element 4 in the metal substrate 3 is X × Y, which is smaller than the above A × B. Furthermore, the volume of the metal substrate 3 is X × Y × Z. The volume is in the range of 70% to 150% of the volume (A × B) ^3/2 of a cube composed of a square having the same area as the area A × B of the cooling surface of the Peltier element 4. When the metal substrate 3 having a volume in such a range is employed, the heat capacity can be increased even when the metal substrate 3 having a contact area equal to or smaller than the area of the cooling surface of the Peltier element 4 is employed. As a result, the temperature difference between the cooling surface and the heating surface can be increased and maintained for a long time.

When the volume of the metal substrate 3 is 70% or more of the volume (A × B) ^3/2 of a cube composed of a square having the same area as the area A × B of the cooling surface of the Peltier element 4, the heat capacity of the metal substrate 3 is Greater than desired value. On the other hand, when the volume of the metal substrate 3 is 150% or less of the volume (A × B) ^3/2 of a cube composed of a square having the same area as the area A × B of the cooling surface of the Peltier element 4, the fire alarm 1 Can be reduced in size. In order to achieve both the increase in the heat capacity of the metal substrate 3 and the miniaturization of the fire alarm 1, the range of 70% to 150% is preferable. More preferably, it is 80% or more and 130% or less, and further preferably 90% or more and 110% or less. The contact area of the metal substrate 3 with the Peltier element 4 may be the same area as the cooling surface.

  As mentioned above, although the preferred embodiment of the fire alarm device according to the present invention has been described, the fire alarm device according to the present invention is not limited to the above-described embodiment, but in various modified embodiments. Can be implemented.

  For example, the form of the fire alarm 1 may not be a regular quadrangular prism but may be a cylinder, a triangular prism, a rectangular parallelepiped, or a polygonal prism having a pentagon or more. Further, the Peltier element 4 may have a form different from that of the fire alarm device 1. The heat shielding member 5 may be configured to cover the side surface of the metal substrate 3. In order to prevent heat radiation to the metal substrate 3 more effectively, a heat insulating material may be put in the space 6. Moreover, it is also possible to employ a fire alarm device that does not include the heat shielding member 5 and exposes the surface of the metal substrate 3 on the Peltier element 4 side. In that case, it is preferable to make the thickness thicker than the metal substrate 3 of the above-mentioned fire alarm device 1 in order to improve the heat dissipation of the metal substrate. The metal substrate may be made of a material other than aluminum and having a thermal conductivity equal to or higher than that of aluminum. For example, the metal substrate may be a substrate made of copper, an aluminum alloy or a copper alloy. As long as the heat shielding member 5 is a material having a thermal conductivity lower than that of the metal substrate, the heat shielding member 5 is made of a material other than the above-described stainless steel and having a thermal conductivity equivalent to or lower than that of stainless steel. May be.

  In the above-described embodiment, the heat shielding member 5 is disposed around the Peltier element 4. However, the width of the metal substrate 3 is made equal to the width of the Peltier element 4 and the metal exposed on both sides of the Peltier element 4. The upper part of the substrate 3 may be covered with a heat shielding member. The upper surface of the Peltier element 4 and the upper surface of the heat shielding member may be flush with each other. In addition to the buzzer 8, the alarm output means may be a light emitting device that outputs light. When the light emitting device is disposed inside the fire alarm device 1, it is preferable to provide a light transmitting window in a part of the heat shielding member 5 or to employ a heat shielding member made of transparent glass. Moreover, you may employ | adopt the alarm output means which outputs both a sound and light.

  Next, each example of the fire alarm device according to the present invention will be described.

Example 1
A Fujitaka Peltier device (FPH1-12707, 15.4V-6.0A, 40 mm × 40 mm) was used as a thermoelectric device, and screwed to the center of a metal substrate made of aluminum having a width of 100 mm × length of 120 mm × thickness of 2 mm. The electronic buzzer and its wiring were placed inside a stainless steel heat shielding member covering the periphery of the Peltier element. The electronic buzzer is a buzzer that operates at about 1.1V. The electronic buzzer and the Peltier element were electrically connected. The fire alarm configured in this way is attached to the wall of 50mm away from the waste oil stove "HIYUNEN" NT50 type with the surface where the Peltier element is exposed facing away from the wall and 500mm above the floor. It was. When the waste oil stove was operated and the vicinity of the surface of the Peltier element reached about 80 ° C., the electronic buzzer sounded.

(Example 2)
The wire was extended from the fire alarm device of Example 1 by 5 m, the electronic buzzer was taken out, and the main body of the fire alarm device and the electronic buzzer were installed in separate rooms. As a result of operating the same stove as in Example 1, the electronic buzzer sounded when the temperature reached about 90 ° C.

(Example 3)
A fire alarm having the same form as the fire alarm 1 shown in FIG. 7 was installed under the same conditions as in Example 1, and a stove similar to that in Example 1 was operated. In this fire alarm, an aluminum block having a width of 35 mm, a length of 35 mm, and a thickness of 40 mm is used as a metal substrate and is fixed to a Peltier element (40 mm × 40 mm). The other conditions were the same as in Example 1. As a result, the electronic buzzer sounded when the temperature reached about 90 ° C. after the stove was operated.

  INDUSTRIAL APPLICABILITY The present invention can be used as a fire alarm device that is easy to install, requires very little maintenance labor, and does not require standby power in general households and business establishments that handle high-temperature heat sources.

It is a perspective view of the fire alarm which concerns on embodiment of this invention. It is AA sectional view taken on the line of the fire alarm shown in FIG. It is sectional drawing when the modification 1 of the fire alarm shown in FIG. 1 is cut | disconnected by the same line as the AA line shown in FIG. FIG. 4 is a perspective view showing a second modified example of the fire alarm shown in FIG. It is a perspective view which shows the modification 3 of the fire alarm device shown in FIG. FIG. 6 is a cross-sectional view taken along line AA of the fire alarm shown in FIG. 5. It is a front view which shows the modification 4 of the fire alarm device shown in FIG. FIG. 8 is a view in which only the Peltier element and the metal substrate of the fire alarm shown in FIG. 7 are taken out and viewed from the bottom surface side of the metal substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fire alarm 2 Recess 3 Metal substrate 4 Peltier element 5 Heat shielding member 6 Space 7 Lead wire 8 Buzzer (alarm output means)
9 hole 10 substrate (heating surface)
11 Substrate (cooling surface)
12 Electrode 13 Electrode 14 P-type semiconductor 15 N-type semiconductor 20 Concavity and convexity 21 Hole 30 Convex portion

Claims (4)

Peltier element,
Alarm output means powered by the Peltier element;
Equipped with a,
A metal substrate having a larger area than the cooling surface is brought into contact with the cooling surface of the Peltier element,
The metal substrate exposed around the Peltier element is covered with a heat shielding member made of a material having a thermal conductivity lower than that of the metal substrate,
The heat shielding member has a box shape having a space between the metal substrate and the alarm output means and a lead wire connecting the alarm output means and the Peltier element are stored in the space. A fire alarm characterized by. The fire alarm device according to claim 1 , wherein an upper surface of the heat shielding member is configured to be lower than an upper surface of the Peltier element . Fire alarm according to claim 1, characterized in Rukoto with holes on the outer surface of the heat shield member. The fire alarm device according to any one of claims 1 to 3 , wherein a black coating is applied to a heating surface of the Peltier element.

Images