REFRIGERATING APPARATUS AND STORGE DEVICE USING THE SAME
A refrigerating apparatus is provided with a cooling unit whose height is greater than width when installed; and a defrosting device for defrosting frost formed on the cooling unit by heat, the defrosting device being in a straight pipe form, wherein the defrosting device is provided in a vertical direction on a side of the cooling unit. By providing the defrosting device in a straight pipe form in the vertical direction on the side of the cooling unit that is long in a longitudinal direction, it is possible to increase the length of the defrosting device and to lower a surface temperature of the defrosting device. Further, as the defrosting device is long, an amount of heat generation is large and defrosting efficiency is high. Moreover, it is possible to manufacture the defrosting device at a low cost as the defrosting device is in a straight pipe form.
Latest Panasonic Patents:
1. Field of the Invention
The present invention relates to a refrigerating apparatus provided with a defrosting device, and a storage device utilizing the refrigerating apparatus.
2. Description of the Related Art
As an example of refrigerating apparatuses provided with a defrosting device, a refrigerating apparatus disclosed in Unexamined Japanese Patent Publication No. 2002-5553 is described.
Referring to
Refrigerator 120 is provided with refrigerating apparatus 125 at its back side bottom (on a right side in
Refrigerating apparatus 125 is cooled by circulation of a refrigerant encapsulated in refrigerating apparatus 125. By an operation of fan 127, a cold air near refrigerating apparatus 125 is blown to freezing chamber 121 and refrigerating chamber 123. In this manner, freezing chamber 121 and refrigerating chamber 123 are cooled.
Here, the air subject to heat exchange and cooling by refrigerating apparatus 125 is an internal air within freezing chamber 121 or refrigerating chamber 123, or an external air that enters while opening freezing chamber door 122 or refrigerating chamber door 124. The internal air is humid as it includes moisture evaporated from food reserved in freezing chamber 121 or in refrigerating chamber 123. Further, a temperature of the external air is higher than that of the internal air. By cooling the high-temperature external air or the high-humidity internal air, frost occurs and deposits on refrigerating apparatus 125. A phenomenon that the frost occurs and deposits is called as frost formation.
If the frost forms on refrigerating apparatus 125, in particular at its heat exchanging surface, the heat exchange, that is, the cooling of the air is hindered. The frost formation also hinders ventilation by fan 127, and an air volume decreases. This causes insufficient cooling. In order to solve the problem of insufficient cooling, the refrigerator disclosed in Publication No. 2002-5553 suppresses the occurrence of the frost, or defrosts the frost that has occurred using glass tube heater 126.
However, when the height of refrigerating apparatus 125 is high, time required for the heat of glass tube heater 126 to reach an upper part of refrigerating apparatus 125 increases. In other words, the time required for defrosting increases.
Further, if the refrigerant is a flammable refrigerant, a surface temperature of glass tube heater 126 is required to be under the ignition temperature of the flammable refrigerant. Lowering the surface temperature of glass tube heater 126 also decreases an amount of heat generation of glass tube heater 126. Consequently, the time required for defrosting further increases.
There is known a defrosting device with decreased time for defrosting, where a heater is provided along the heat exchanging surface of refrigerating apparatus 125. For such a heater, a pipe heater formed by inserting a wire heater into a metallic pipe and bending the metallic pipe is used, instead of glass tube heater 126. However, the pipe heater is expensive, as it requires a higher material cost and a processing cost.
SUMMARY OF THE INVENTIONAn object of the present invention is to provide an inexpensive refrigerating apparatus with high defrost efficiency even when a surface temperature of a defrosting device is low.
A refrigerating apparatus according to the present invention is provided with a cooling unit whose height is greater than width when installed; and a defrosting device for defrosting frost formed on the cooling unit by heat, the defrosting device being in a straight pipe form, wherein the defrosting device is provided in a vertical direction on a side of the cooling unit. By providing the defrosting device in a straight pipe form in the vertical direction on the side of the cooling unit that is long in a longitudinal direction, it is possible to increase the length of the defrosting device and to lower the surface temperature of the defrosting device. Further, as the defrosting device is long, an amount of heat generation is large and defrosting efficiency is high. Moreover, it is possible to manufacture the defrosting device at a low cost as the defrosting device is in a straight pipe form.
Referring to
Cooling unit 2 is in a rectangular shape whose height A is 340 mm and width B is 240 mm. In other words, cooling unit 2 is longitudinally elongated. As shown in
Referring to
The following describes defrosting of cooling unit 2 by defrosting device 5. By conducting electricity to defrosting device 5 using leads 10, heat generating unit 8 of wire heater 7 generates heat. By transferring radiation heat from heat generating unit 8 to refrigerant pipe 4 or to cooling fin 3, the frost formed on cooling unit 2 melts, and thus the defrosting is carried out.
As shown in
As an amount of heat generation of wire heater 7 becomes larger, it is possible to decrease time required for defrosting and improve efficiency of defrosting device 5. In the meantime, a reference upper limit of operating temperature is set when designing wire heater 7. The reference upper limit of operating temperature affects life duration of wire heater 7. For example, if a high temperature is set as the reference upper limit of operating temperature, life duration of wire heater 7 becomes shorter. In this case, in order to increase the amount of heat generation of wire heater 7 within the limit of the reference upper limit of operating temperature, it is necessary to increase total length C of heat generating unit 8. Consequently, the life duration and the amount of heat generation are ensured with defrosting device 5 according to the first embodiment, as total length C of heat generating unit 8 is long.
Further, when the flammable refrigerant is used for cooling unit 2, the surface temperature of defrosting device 5 is required to be set low. For example, the surface temperature of defrosting device 5 is required to be lower than the ignition temperature of the flammable refrigerant by 100 K or more. According to defrosting device 5 of this embodiment, when isobutane whose ignition temperature is 494 degrees Celsius is used as a refrigerant, the reference upper limit of operating temperature is set such that the surface temperature of glass tube 6 of defrosting device 5 is lower than 394 degrees Celsius. Consequently, the amount of heat generation can be sufficiently ensured with defrosting device 5 according to the first embodiment, even when the surface temperature of glass tube 6 is required to be set low.
Moreover, as defrosting device 5 in a straight pipe form is provided on the side of cooling unit 2, a distance between defrosting device 5 and a part of cooling unit 2 at the most distant position from defrosting device 5 becomes shorter in cooling unit 2 whose height A is longer than width B, as compared to the case in which defrosting device 5 is provided below cooling unit 2. With this configuration, the heat from defrosting device 5 is easily transferred to an entirety of cooling unit 2.
Furthermore, according to the conventional refrigerator, as shown in
It should be noted that defrosting device 5 is configured by providing wire heater 7 within glass tube 6. A heat transmission ratio of glass is considerably higher than that of metals and such. Accordingly, defrosting device 5 using glass tube 6 efficiently generates radiation heat. In other words, cooling unit 2 is efficiently heated and defrosted by the radiation heat from wire heater 7.
Here, when transporting refrigerating apparatus 1, a force attributed to vibration due to the transportation is applied to wire heater 7. If strength of wire heater 7 is insufficient, the coiled form of heat generating unit 8 of wire heater 7 deforms due to the force. Heat generating unit 8 is biased toward the bottom when deforming due to its own weight. In other words, spiral pitches of heat generating unit 8 in the coiled form become uneven. The unevenness of the spiral pitches causes uneven heat generation, resulting in localized heating in glass tube 6. Further, the unevenness of the spiral pitches brings heat generating unit 8 into contact with glass tube 6, causing abnormal noise. According to the first embodiment, the strength of wire heater 7 can be ensured by setting the diameter of wire heater 7 to be equal to or grater than 0.21 mm. With this, it is possible to suppress the deformation of heat generating unit 8 in the coiled form, and to prevent the localized heating of glass tube 6 and the abnormal noise from being caused.
Defrosting device 51 is fixed to cooling unit 2 such that a side of spiral pitch P1 comes upside. Specifically, defrosting device 51 is provided such that a side on which a coiled portion of heat generating unit 8 of wire heater 7a is dense comes upside. When defrosting device 51 is fixed to cooling unit 2, the coiled form of heat generating unit 8 becomes wider toward downside due to its own weight. According to the first embodiment, by the coiled form of heat generating unit 8 being wider toward downside, the spiral pitches of entire heat generating unit 8 becomes substantially even.
By the spiral pitch of heat generating unit 8 becoming even, the amount of heat generation of wire heater 7a per unit area becomes even. By the amount of heat generation becoming even, it is possible to suppress the unevenness of the defrosting and to improve the defrosting efficiency of defrosting device 51. In addition, with this configuration, it is possible to use wire heater 7a whose diameter is small. It is appreciated that, while the above description is given regarding the example in which wire heater 7a of defrosting device 51 includes two types of spiral pitches, wire heater 7a can include three or more types of spiral pitches.
Third EmbodimentSimilarly to
As shown in
The following describes defrosting of cooling unit 2 by defrosting device 5. Similarly to the first embodiment, by transferring the radiation heat from heat generating unit 8 of wire heater 7 to refrigerant pipe 4 or to cooling fin 3, the frost formed on cooling unit 2 melts, and thus the defrosting is carried out.
As defrosting device 5 is disposed in a slanted manner such that horizontal distance D is shorter than horizontal distance F, the radiation heat from wire heater 7 is directly transferred to drain pan 13 provided below cooling unit 2. In other words, the frost forming on drain pan 13 is defrosted. With this configuration, it is not necessary to separately provide a heater for defrosting drain pan 13. This allows an inexpensive structure. It is appreciated that defrosting device 51 or 52 described in the second embodiment or the third embodiment can also be used as defrosting device 5.
According to the structure shown in
Moreover, as shown in
Storage device 21 is internally provided with compressor 25, condenser 26, decompressor 27, and refrigerating apparatus 1 according to one of the first to fourth embodiments. As described according to the first to fourth embodiments, refrigerating apparatus 1 is provided with defrosting device 5 and cooling unit 2. Compressor 25, condenser 26, decompressor 27, and cooling unit 2 of refrigerating apparatus 1 are coupled in a circular pattern by piping, thereby configuring a refrigeration cycle. According to the fifth embodiment, cooling unit 2 serves as an evaporator. Refrigerating apparatus 1 is disposed in first storage chamber 22a. Further, drain pan 29 for receiving the water resulted from the defrosted frost is provided below refrigerating apparatus 1.
First storage chamber 22a is provided with blower 28. Blower 28 circulates the cold air cooled by cooling unit 2 within first storage chamber 22a as shown by arrow Y. Further, blower 28 circulates a part of the cold air of first storage chamber 22a within second storage chamber 22b through communicating channels 24a and 24b as shown by arrow Z. With this configuration, interiors of first storage chamber 22a and second storage chamber 22b are cooled.
It is possible for storage device 21 according to the fifth embodiment to efficiently defrost the frost formed on cooling unit 2 by using refrigerating apparatus 1 according to one of the first to fourth embodiments as the evaporator. Further, as the time required for defrosting is short, it is possible to suppress temperature rise in first storage chamber 22a and second storage chamber 22b. With this, it is possible to prevent deterioration of items stored in storage device 21. Moreover, by an improvement of the defrosting efficiency and reduction of the time for the defrosting operation, it is possible to improve efficiency of a cooling operation of storage device 21 and to reduce an amount of power consumption.
Claims
1. A refrigerating apparatus, comprising:
- a cooling unit whose height is greater than width when installed; and
- a defrosting device for defrosting frost formed on the cooling unit by heat, the defrosting device being in a straight pipe form, wherein
- the defrosting device is provided in a vertical direction on a side of the cooling unit.
2. The refrigerating apparatus according to claim 1, wherein
- the defrosting device includes: a glass tube; a wire heater disposed within the glass tube; leads connected to the wire heater; and caps respectively covering openings on both sides of the glass tube.
3. The refrigerating apparatus according to claim 2, wherein
- the wire heater includes a heat generating unit in a coiled form that is configured by a metal resistant body, and
- a diameter of the metal resistant body is equal to or greater than 0.21 mm.
4. The refrigerating apparatus according to claim 2, wherein
- the wire heater includes a heat generating unit in a coiled form that is configured by a metal resistant body, and
- the heat generating unit has at least two types of spiral pitches, and is disposed such that a side with a smaller one of the spiral pitches comes upside.
5. The refrigerating apparatus according to claim 2, wherein
- the wire heater includes a heat generating unit configured by a carbon fiber.
6. The refrigerating apparatus according to claim 1, wherein
- the defrosting device is disposed in a slanted manner such that an upper side of the device is close to the cooling unit and a lower side of the device is gradually spaced away from cooling unit toward downside.
7. A storage device, comprising:
- a refrigeration cycle including a compressor, a condenser, a decompressor, and an evaporator that are coupled in a circular pattern by piping;
- a storage chamber; and
- a blower for circulating a cold air that has been cooled by the evaporator in the storage chamber, wherein
- the evaporator is used as the refrigerating apparatus according to claim 1.
Type: Application
Filed: Nov 11, 2010
Publication Date: Jun 16, 2011
Applicant: PANASONIC CORPORATION (Osaka)
Inventor: Toshiki MAEDA (Shiga)
Application Number: 12/944,513
International Classification: F25D 21/08 (20060101); F25D 19/00 (20060101);