JPH0612368Y2 - Heat pipe type heat equalizer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat pipe type heat equalizer provided in, for example, a bread oven for baking edible bread.

2. Description of the Related Art For example, a heating device used in a bread oven has two heating systems, a combustion gas ventilation system and a heating wire system. When the two methods are compared, the heating wire method has a problem that the energy cost is high, whereas the combustion gas ventilation method has a problem of H which is a combustion product of gas.
_{Since 2} O keeps the inside of the oven at an appropriate humidity, there is an advantage that the bread is baked mildly. for that reason,
In both of the above methods, the fuel gas ventilation method is receiving particular attention. As shown in FIG. 1, in this combustion gas ventilation type pan / oven, an upper heater 3 and a lower heater 4 are provided as a soaking device above and below a support plate 2 mounted in a case 1, and an upper heater is further provided. 3 has a structure in which an exhaust pipe 5 is arranged around the periphery of the structure 3.

Problems to be Solved by the Invention However, there are the following problems in the above-mentioned conventional bread and oven using the combustion gas ventilation system.

That is, as shown in FIG. 2, in the conventional pan-and-oven system of the combustion gas ventilation system, heating is performed by the combustion gas flowing in the gas pipe 6 of the upper heater 3, so that the gas pipe 6
The temperature of the combustion gas removed in the process of flowing inside drops,
There was a problem that uniform heating was not performed.

Therefore, in order to solve the above problems, as shown in FIG. 3, a heat pipe 7 is provided instead of the gas pipe, and one end of the heat pipe 7 is heated by the combustion gas flowing in the gas pipe 8. Therefore, there has been proposed a bread oven in which a heat pipe type heat equalizer for heating the inside of the oven via the working fluid in the heat pipe 7 is provided. The use of such a heat pipe type heat equalizer has an advantage that uniform heating can be performed in the oven because of the function of the heat pipe that uniform heating can be performed over the entire length.

By the way, when applying a heat pipe to a bread oven, it is necessary to set the surface temperature of the heat pipe to 200 to 350 ° C. In that case, the temperature of the working fluid in the heat pipe needs to be 250 to 400 ° C., and the working fluid which can meet the need is THERM S3 which is a mixture of diphenyl and diphenyl oxide.
00 (product name) was valid. However, when therms 300 exceeds 350 ° C., it undergoes thermal decomposition to generate non-condensable gases such as hydrocarbons and loses its function as a working fluid. As a result, the life of the heat pipe is significantly shortened. There was a drawback. Therefore, therm s 3
When 00 is applied as the working fluid in the heat pipe of the heat pipe type heat equalizer used for the above-mentioned pan and oven, the upper limit of the required heating temperature for the working fluid is the upper limit of the heatable temperature for the working fluid. There is a problem that the life of the heat pipe is shortened.

Therefore, naphthalene has recently attracted attention as such a working fluid without danger. That is, if naphthalene is used as a working fluid, naphthalene can be put into practical use up to its critical temperature of 475 ° C. without any inconvenience, and the number of merits, which is an index of superiority or inferiority as a working fluid for heat pipes, is 1. There is an advantage that it is as large as 3.47 × 10 ¹⁰ w / m ² while it is 52 × 10 ¹⁰ w / m ² . However, as a problem that occurs when naphthalene is used as the working fluid in this way, there is a problem that preheating is necessary before starting the operation. That is, when the soaking device is not in operation, the entire device is normally cooled to normal temperature, but naphthalene has a melting point of 79.5 ° C.
Therefore, naphthalene is usually solid when not operating at room temperature. On the other hand, in order to exert the heat transport function as the working fluid of the heat pipe, the working fluid needs to be a fluid. Therefore, when naphthalene is used as the working fluid of the heat pipe, preheating is required when starting up. It is necessary to liquefy naphthalene.

However, when naphthalene is applied as the working fluid of the heat pipe 7 of the conventional heat pipe type heat equalizer as shown in FIG. 3, only one end in the longitudinal direction of the heat pipe 7 is heated even when the device rises. Therefore, it takes a long time to completely liquefy naphthalene to function as a working fluid, which is not practical.

This invention has been made in view of the above conventional circumstances, and even when naphthalene is used as the working fluid of the heat pipe, it does not require long-time preheating at the time of rising and shortens the rising time. It is an object of the present invention to provide a heat pipe type heat equalizer that can quickly and uniformly heat an object to be heated.

Means for Solving the Problems That is, the heat pipe type heat equalizer of the present invention has an inner pipe made of a corrugated tube communicating with a gas pipe, inside an outer pipe made of a corrugated tube arranged substantially horizontally. It is housed almost horizontally in a state of being eccentric downward with respect to the outer pipe, a wick structure is formed in the gap between the inner pipe and the outer pipe, and naphthalene is housed as a working fluid between the inner pipe and the outer pipe. It is characterized by.

Function In the heat pipe type heat equalizer of the present invention, since the outer pipe is arranged substantially horizontally, the naphthalene as the working fluid stored between the outer pipe and the inner pipe is evenly distributed in the longitudinal direction of the pipe. It is distributed.
Then, when a high-temperature combustion gas is circulated inside the inner pipe, the liquid phase of naphthalene guided by the wick structure to the outer surface of the inner pipe is evaporated (vaporized), and the heat of the combustion gas is absorbed as latent heat. When vaporized naphthalene (vapor phase naphthalene) reaches the inner surface of the outer pipe, it is deprived of heat by the relatively low temperature outer pipe and condensed (liquefied).
Therefore, the heat of the hot combustion gas inside the inner pipe is transferred to the outer pipe by the naphthalene. Here, although the combustion gas flowing inside the internal pipe has a high temperature on the inlet side of the combustion gas, the temperature gradually drops while flowing inside the internal pipe and becomes relatively low on the outlet side, Since naphthalene as a working fluid between the inner pipe and the outer pipe also transfers heat in the longitudinal direction of the pipe, the object to be heated outside the outer pipe is uniformly heated in the longitudinal direction of the pipe.

In addition, since a corrugated tube is used as the inner pipe, the heat transfer area can be increased. Therefore, the heating efficiency of naphthalene by the combustion gas flowing in the inner pipe is high, and the naphthalene can be efficiently heated in a short time. Further, since the corrugated tube is also used as the outer pipe, the heat transfer area of the outer pipe is large, so that the heating target outside the outer pipe can be efficiently heated.

Furthermore, most of the naphthalene used as a working fluid in the liquid state is retained in the lower part of the horizontal outer pipe by gravity, and part of it is in the wick structure by the wick structure and the outer peripheral surface of the inner pipe. It is in a state that exists in. Therefore, when not operating (at room temperature), most of the naphthalene is solidified in the lower part of the outer pipe, and part of it is solidified in the wick structure and the outer surface of the inner pipe. Further, in this invention, since the inner pipe is eccentric to the outer pipe downward, the inner pipe also comes into direct contact with the naphthalene accumulated and solidified in the lower portion of the outer pipe. From such a state, if hot combustion gas is circulated inside the inner pipe to raise the device, the naphthalene adhering to the outer peripheral surface of the inner pipe or the lower part of the inner pipe is contacted and accumulated in the inner pipe lower part. Naphthalene is heated directly by the heat of combustion gas and immediately begins to melt and liquefy,
Subsequently, the portion of naphthalene that is not in direct contact with the inner pipe is also rapidly melted and liquefied, and the entire naphthalene is liquefied quickly. Further, these actions are further promoted by increasing the heat transfer area by using the corrugated tube as the internal pipe, and as a result, the naphthalene that had solidified at room temperature is eventually lifted when the device starts up. It liquefies efficiently in a remarkably short time and becomes a state where it can function as a working fluid.

Embodiment An embodiment of the present invention will be described below.

FIG. 4 shows a heat pipe used in the heat pipe type heat equalizer of one embodiment of the present invention. As shown in the figure, the heat pipe 11 has an inner pipe 13 housed in an outer pipe 12. As the internal pipe 13, a corrugated tube, that is, a pipe whose wall surface is corrugated is used. A corrugated tube similar to the above is also used as the outer pipe 12. Then, naphthalene as a working fluid is housed between the inner pipe 13 and the outer pipe 12.

Further, a wick structure for guiding the liquid-phase working fluid from the inner surface of the outer pipe 12 to the outer surface of the inner pipe 13 is formed between the inner surface of the outer pipe 12 and the outer surface of the inner pipe 13. Therefore, naphthalene as a working fluid contacts the outer surface of the inner pipe 13 in a liquid phase, is heated and evaporated on the outer surface of the inner pipe 13, and the naphthalene in the vapor phase contacts the inner surface of the outer pipe 12. The heat is removed and condensed (liquefied), and eventually the heat is transferred from the inner pipe 13 to the outer pipe 12. Note that the working fluid can move in the longitudinal direction of the pipe as well as a normal heat pipe, and therefore the working fluid also carries heat transfer in the longitudinal direction of the pipe.

Here, as the wick structure, a wire mesh wick, a groove, a wick filled with fine particles or sintered particles, or the like can be adopted.

The above heat pipe 11 is applied as the heat pipe of the heat equalizer shown in FIG.
The heat pipe type heat equalizer of the present invention is formed by making the combustion gas flow into the inner pipe 13.

Therefore, according to the heat pipe type heat equalizer of the above embodiment, the object is heated as follows.

When the apparatus is not in operation, the naphthalene housed between the outer pipe 12 and the inner pipe 13 is usually solidified at room temperature. Here, a part of the naphthalene is solidified in the wick structure and on the outer peripheral surface of the inner pipe 13, and most of the rest remains in the lower part of the horizontal outer pipe. Since it is eccentric to the outer pipe 12 downward, the lower part of the inner pipe 13 is in contact with the naphthalene that is solidified and accumulated in the lower part of the outer pipe.

The apparatus is activated from the above-described state, the combustion gas is caused to flow in the gas pipe 8, and the high temperature combustion gas is caused to flow into the inner pipe 13 of the heat pipe 11. Thereby, the naphthalene housed between the outer pipe 12 and the inner pipe 13 is uniformly heated over the entire length of the heat pipe 11, and the naphthalene is liquefied rapidly and efficiently.

That is, naphthalene that adheres to the outer peripheral surface of the inner pipe and solidifies, or naphthalene that solidifies in the lower part inside the horizontal outer pipe and contacts the lower part of the inner pipe 13. Is directly heated by the heat of the internal pipe and is rapidly heated to start liquefaction, and subsequently, the remaining portion of naphthalene is also rapidly melted and liquefied. Moreover, the heat transfer area is increased by using a corrugated tube as the inner pipe 13, and since the heat transfer area of the corrugated tube is about 1.5 times that of the straight tube, the heat transfer per unit time is reduced. The passing amount is also about 1.5 times. As a result, the preheating time for the liquefaction of naphthalene by the combustion gas flowing in the internal pipe 13 is significantly shortened.

Following the liquefaction of naphthalene as described above, the temperature of the liquid phase naphthalene further rises due to the heat from the outer surface of the internal pipe, exceeds its boiling point, and vaporizes (vaporizes) to become a vapor phase. The high temperature naphthalene in the vapor phase reaches the inner surface of the outer pipe 12 and gives heat to the outer pipe 12 to recondense (liquefy). The naphthalene in the liquid phase is guided to the inner surface of the inner pipe 13 by the wick structure, vaporized again on the inner surface of the inner pipe 13, and the same process as described above is repeated. In this way, from the inner pipe 13 to the outer pipe 1
The heat is transported to 2, and the outer pipe 12 heats the inside of an oven or the like in which a heat equalizer is arranged. Further, since heat is also transported in the pipe longitudinal direction by naphthalene as a working fluid, it is possible to uniformly heat the pipe longitudinal direction.

Effect of the Invention As described above, according to the heat pipe type heat equalizer of the present invention, an inner pipe made of a corrugated tube communicating with the gas pipe is formed inside the outer pipe arranged substantially horizontally from the corrugated tube. It is accommodated almost horizontally in a downwardly eccentric state with respect to the outer pipe and a wick structure is formed in the gap between the inner pipe and the outer pipe. Although it uses naphthalene that is solidified at room temperature, the solidified naphthalene can be quickly liquefied at the time of starting the device and can immediately function as a working fluid. Since the working fluid transfers heat between the inner pipe and the outer pipe and heat in the longitudinal direction of the pipe, it is heated by the object to be heated, for example, pan-au. The bread and the like in the oven can be heated efficiently and uniformly. Moreover, since naphthalene having a high practical temperature range is used as the working fluid, there is an effect that it is possible to eliminate the risk of shortening the life due to the alteration of the working fluid.

[Brief description of drawings]

FIG. 1 is a sectional view showing a combustion gas ventilation type pan / oven, FIG. 2 is a perspective view of an upper heater arranged in the pan / oven shown in FIG. 1, and FIG. 3 is a conventional heat pipe type uniform. FIG. 4 is a perspective view of a heat device, and FIG. 4 is a partial perspective view of a heat pipe type heat equalizer of one embodiment of the present invention. 8 ... Gas pipe, 12 ... External pipe, 13 ... Internal pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Masataka Mochizuki 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Creator Koichi Masue 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Shinichi Sugihara 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (56) Reference JP-A-53-113357 (JP, A) -50368 (JP, U) Actually opened 57-132979 (JP, U) Actually opened 58-141109 (JP, U) Actually opened 59-67716 (JP, U) JP-B 58-12502 (JP, B2) ) Actual public Sho 54-44692 (JP, Y2)

Claims (1)

[Scope of utility model registration request] 1. An inner pipe made of a corrugated tube communicating with a gas pipe is housed in an outer pipe made of a corrugated tube arranged substantially horizontally in a substantially eccentric manner downwardly with respect to the outer pipe. A heat pipe type heat equalizer characterized in that a wick structure is formed in a gap between the inner pipe and the outer pipe, and naphthalene is stored as a working fluid between the inner pipe and the outer pipe.