JP2006317103A - Superheated steam generator and heat treatment apparatus using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral fluid passage structure capable of reducing pressure losses in the boundary to brackish water in a superheated steam generator. <P>SOLUTION: A spiral fluid passage 3 is formed inside a heating plate 2. In the gas-liquid two-phase area of the fluid passage, the passage is gradually increased in width. Then the increased width of the passage is either maintained or made slightly larger to efficiently generate superheated steam. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a superheated steam generator that generates superheated steam that is steam of 100 ° C. or higher, and a heat treatment apparatus using the same. In particular, the present invention relates to an electromagnetic induction heating type superheated steam generator that can obtain superheated steam with good thermal efficiency, and is simple and easy to handle, and a heat treatment apparatus using the same.

    In general, cooking equipment such as an open flame, an oven, a grilled plate, and a frying pan is used for cooking pottery. These cooking appliances require a heating time of several minutes to several tens of minutes when trying to put fire into the food, so it is strongly desired to shorten the cooking time. Therefore, a cooking method using superheated steam that has recently been heated to 100 ° C. or more has attracted attention. In particular, in the commercial food processing industry and households, a compact and low-cost superheated steam generator is strongly desired, and as an example, a superheated steam generation chamber is integrally provided in a heat treatment chamber is known. .

    For example, it is known that a superheated steam generator is integrally provided in a heat treatment apparatus that heat-treats an object to be heated, thereby forming a compact and simple heat treatment apparatus (Patent Document 1). That is, in this, a fluid passage is provided inside a heating plate for heating an object to be heated in the heat treatment chamber, and water or saturated steam is supplied from the fluid inlet to the fluid passage to heat the heating plate. Then, water or saturated steam in the fluid passage is superheated to generate superheated steam, and the superheated steam generated in the fluid passage is supplied into the heat treatment chamber. In this case, by heating a heating plate that heat-treats the object to be heated, water or saturated steam in the fluid passage formed in the heating plate is also heated to generate superheated steam. It is possible to obtain a generator and a heating device using this generator, and in particular, since there is no transfer of superheated steam between the superheated steam generator and the heat treatment chamber, there is no heat loss of the superheated steam, Thermal efficiency is very good.

    In addition, as an example of the superheated steam generator, the fluid passage provided in the heating plate of the superheated steam generator is made into a spiral shape, and at the brackish water boundary portion (portion where water and steam are mixed in the fluid passage) in the steam generation process It is known to increase the heating power by increasing the number of turns of the electromagnetic induction heating coil so as to increase the speed at which water turns into steam. In addition, it is also known to further increase the speed at which water becomes steam by expanding the passage width of the brackish water boundary region to increase the heat transfer area (Patent Document 2).

    That is, a flat plate-like induction heating coil, a magnetic heated body heated by the induction heating coil, and a spiral fluid passage extending outward from a central portion provided to be able to transfer heat to the magnetic heated body An electromagnetic induction heating type instantaneous steam generator that changes the water supplied to one end of the fluid passage by heating the magnetic heated body into superheated steam and discharges it from the other end of the fluid passage. Thus, the number of coil turns of the induction heating coil is set to a larger value in a portion corresponding to a passage in the middle of the fluid passage than a portion corresponding to a passage closer to both ends.

In this case, the water flowing in the spiral fluid passage that spreads in a planar shape by the heating of the magnetic heated body is converted into steam. Moreover, the brackish water boundary part in this fluid channel | path can be heated with a higher heating power, and a vapor | steam can be obtained at high speed.
JP 2004-187725 A JP 2003-203751 A

    However, the one in Patent Document 1 has a problem that even when trying to heat water in the fluid passage until it becomes superheated steam, the superheated steam cannot be efficiently generated. The concrete structure of the passage for the fluid path for efficiently generating superheated steam remains as a research subject.

    Moreover, in what is shown in Patent Document 2, the spiral fluid passages have the same width. In this case, when the water changes into steam in the brackish water boundary region, it expands greatly and the flow velocity increases and the pressure loss increases, so that the change from liquid to vapor is not performed efficiently, and is discharged from the fluid outlet. The result is that the superheated steam is not changed and moisture remains. Further, even if the bottom of the fluid passage is changed to vapor, a so-called dry-out state occurs in which moisture remains in the fluid passage, and the change from liquid to vapor is not efficiently performed.

    Moreover, in another embodiment of Patent Literature 2, a passage width of a brackish water boundary region is provided with a diameter larger than that of other portions, and the heat transfer area is expanded. However, even if the passage width of the brackish water boundary region is larger than that of other portions, the same passage width is provided in the brackish water boundary region, and the above-described problems are not solved. That is, if the inside of the brackish water boundary region has the same width, the flow velocity of the fluid increases immediately and the pressure loss increases rapidly. As a result, the liquid is not changed to saturated vapor in this region, and superheated vapor cannot be obtained reliably. In addition, after the inside of the brackish water boundary region, it has returned to the original passage width. In this region, the flow velocity becomes faster and faster, so the pressure loss is large, and the gas-liquid two-phase flow brought into this region is increasing. It cannot be changed to superheated steam more and more, and cannot be completely superheated steam.

    In addition, since the spiral fluid passage is formed on the vertical surface and the heating surface is on the side surface, the liquid that tends to accumulate on the bottom side of the fluid passage in the brackish water boundary region may not be sufficiently heated. In addition, a vapor layer is formed on the upper half side of the spiral fluid communication path and a moisture layer is formed on the lower half side, so that the superheated steam cannot be efficiently generated as a whole.

    Therefore, as a result of examining whether or not saturated water can be reliably and efficiently changed to saturated steam in the brackish water boundary region, that is, in the state of gas-liquid two-phase flow, The present invention has been completed by finding the fact that it is sufficient to reduce the above. That is, an object of the present invention is to provide a spiral fluid passage structure capable of reducing pressure loss at the brackish water boundary portion in the superheated steam generator.

According to the first aspect of the present invention, a metal heating plate disposed in a lower portion of a housing forming a superheat treatment chamber is heated by heating means disposed in a lower portion of the heating plate, and passes through the heating plate. A superheated steam generator in which a flowing fluid is heated from water to superheated steam at once,
A spiral fluid passage formed in a substantially horizontal direction inside the heating plate;
A water introduction portion provided at a center portion of the spiral of the fluid passage of the heating plate;
A fluid outlet provided at the outer end of the spiral of the fluid passage of the heating plate;
The spiral fluid passage has a diameter-expanded portion formed by gradually increasing the passage width in the fluid passage from the water introduction portion toward the fluid outlet portion,
The water introduced from the water introduction part is superheated at a stretch by passing through the spiral fluid passage, and superheated steam is generated.

The invention according to claim 2 is the superheated steam generator according to claim 1,
The expanded diameter portion is provided until the water in the fluid passage changes from saturated water to gas-liquid two-phase flow to saturated steam,
From the downstream end of the enlarged diameter portion to the fluid extraction portion, the passage width of the downstream end of the enlarged diameter portion is formed to be the same as or slightly increased.
From the water introduction part to the upstream end part of the enlarged diameter part, it is formed to be the same as or slightly increased from the enlarged width of the enlarged diameter part.

The invention according to claim 3 is the superheated steam generator according to claim 1 or 2,
A water guide groove extending in the fluid passage direction is formed on the bottom surface of the enlarged diameter portion.

The invention according to claim 4 is the superheated steam generator according to claim 3,
The water guide grooves are provided in a plurality of rows in the passage width direction of the fluid passage.

The invention according to claim 5 is the superheated steam generator according to claim 3 or 4,
The water guide groove is formed in the latter half portion of the enlarged diameter portion.

The invention according to claim 6 is the superheated steam generator according to any one of claims 1 to 5,
A heated member made of a magnetic shunt alloy is integrally attached to the lower surface side of the heating plate.

The invention according to claim 7 is a heat treatment apparatus using the superheated steam generator according to any one of claims 1 to 6,
A housing forming the overheat treatment chamber;
A metal heating plate that is disposed in the lower part of the housing and heat-treats the object to be heated set in the housing;
A water supply means connected to the water introduction part of the fluid passage and supplying water to the fluid passage;
A superheated steam supply path connected to the fluid take-out section and having a tip opened to the superheat treatment chamber;
Heating means for heating the heating plate, heating water in the fluid passage to generate saturated water, and further heating the saturated water to generate superheated steam via saturated steam;
It is characterized by providing.

The invention according to claim 8 is the heat treatment apparatus using superheated steam according to claim 7,
The heating means includes a heated member made of a magnetic shunt alloy integrally attached to the lower surface side of the heating plate, and an electromagnetic induction heating member that electromagnetically heats the heated member.

    According to the first aspect of the present invention, saturated water can be efficiently changed to saturated steam in a gas-liquid two-phase flow region, and superheated steam can be efficiently obtained with a simple configuration.

    According to the second aspect of the present invention, the fluid flow rate of water or gas can be adjusted smoothly from the water introduction part through the enlarged diameter part to the fluid extraction part, and the pressure loss of the fluid can be greatly suppressed. In addition, superheated steam can be obtained efficiently.

    According to the invention according to claim 3, by providing the water guide groove, it is possible to leave as much water as possible in the water guide groove using the capillary phenomenon, that is, it is possible to suppress the water from leaving the bottom surface, Dryout can be reduced. Therefore, saturated water can be efficiently converted into saturated steam, and superheated steam can be obtained with certainty.

    According to the invention which concerns on Claim 4, saturated water can be changed into saturated steam still more efficiently, and superheated steam can be obtained more reliably.

    According to the invention which concerns on Claim 5, since it is set as the structure which leaves a water | moisture content in a bottom face in the area | region with much generation | occurrence | production of dryout, it can change to saturated steam reliably with a simple structure.

    According to the invention of claim 6, by using the magnetic shunt alloy, the temperature can be controlled without providing an electric circuit, so the configuration is simple. In addition, since it does not have an electric circuit, it can be washed with water.

    According to the seventh aspect of the invention, in the gas-liquid two-phase flow region, saturated water can be efficiently changed to saturated steam, and superheated steam can be obtained efficiently with a simple configuration. An object to be heated can be effectively heat-treated.

    According to the eighth aspect of the present invention, since the temperature can be controlled without using an electric circuit by using the magnetic shunt alloy, the configuration is simple. In addition, since the electric circuit is not provided, the apparatus can be easily disassembled and washed with water.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings.

    1 and 2 show Embodiment 1 of the present invention. FIG. 1 is a schematic sectional view of a heat treatment apparatus, and FIG. 2 is a plan view of an upper heating plate of a metal heating plate. The heating plate 2 of the superheated steam generator 1 is formed by laminating an upper heating plate 2a and a lower heating plate 2b, and each is formed by forming an aluminum material so as to have a disk shape in plan view. The heating plate 2 is disposed substantially horizontally, and a spiral fluid passage 3 is formed in the heating plate 2 in a substantially horizontal direction. A water introduction portion 6 for introducing water into the fluid passage 3 is provided at the center position of the upper surface portion of the heating plate 2, that is, at the center position of the spiral of the fluid passage 3. A water pipe 13 serving as a water supply means is connected to the water introduction unit 6, and the water pipe 13 extends parallel to the upper surface of the heating plate 2 and protrudes to the outside of the heat treatment chamber 11. It is designed to be connected to the water source. On the other hand, a fluid take-out portion 7 that is connected to the spiral outer end of the fluid passage 3 and extracts the superheated steam in the passage 3 is provided around the upper surface of the heating plate 2. . The fluid take-out unit 7 is in contact with a pipe 14 that is a superheated steam supply path, and supplies superheated steam to the heat treatment chamber 11.

    The heat treatment apparatus 10 is provided with a housing 12 that covers the upper space of the heating plate 2, and a heat treatment chamber 11 is formed in the housing 12. On the lower surface side of the heating plate 2, as shown in FIG. 6, the heating plate 2 is heated and the fluid (water or saturated water) in the fluid passage 3 is heated to generate superheated steam. A magnetic shunt alloy 21 as a member to be heated is integrally attached.

    On the lower surface side of the magnetic shunt alloy 21, an electromagnetic induction heating member 22 including an induction heating coil 23 and an inverter 24 connected to the induction heating coil 23 is disposed as the heating means 20. The heating plate 2 only needs to be stacked on the box containing the electromagnetic induction heating member 22 and does not need to be mechanically connected. It can also be used on the upper surface of a normal IH cooker or the like.

    The details of the spiral fluid passage 3 which is an important configuration of the present invention will be described with reference to FIGS.

    Normal temperature water such as tap water supplied from the water introduction part 6 to the spiral fluid passage 3 is heated to become saturated water at 100 ° C., and then becomes saturated steam at about 100 ° C. through a gas-liquid two-phase flow state, It is further heated to change to superheated steam at 200 ° C., for example. As shown in FIG. 3, the width of the spiral fluid passage 3 is set to the same width b1 since there is almost no volume change from the water introduction part 6 to saturated water. Thereafter, the volume expansion is remarkably large until the pressure changes from saturated water to saturated steam through a gas-liquid two-phase flow. For example, assuming that the spiral fluid passage 3 has the same passage width, the horizontal axis represents the transition from saturated water to gas-liquid two-phase flow to saturated steam, and the pressure loss is the logarithmic scale vertical axis. As shown, the influence of pressure loss is large in the latter half region where the steam becomes 60% and 80% saturated. As a countermeasure, in the first embodiment, as shown in FIG. 3, the passage width of the spiral fluid passage 3 is gradually enlarged to suppress an increase in the flow velocity and greatly reduce the pressure loss. As a result, it has become possible to efficiently change to saturated steam with a compact structure, and superheated steam can be obtained. The same passage width b2 is used from the vicinity where 100% saturated steam is obtained to the fluid extraction portion.

    Furthermore, as shown in FIG. 5, a plurality of rows of water guide grooves are provided on the bottom surface 3 a of the spiral fluid passage 3. By providing the water guide groove 5, moisture on the bottom surface is held in the water guide groove 5 by capillary action, and dryout can be prevented. Particularly, it is effective and preferable to provide the gas-liquid two-phase flow in a region with little moisture, that is, in the latter half of the enlarged diameter portion 4.

    An object to be heated (not shown) is placed in the heat treatment chamber 11 to be heat treated. In addition, you may provide the metal-mesh (not shown) for mounting a to-be-heated material in the position away from the heating plate 2 upper surface upwards.

    When the inverter 24 is energized, the magnetic shunt alloy 21 is heated by the induction coil 23 and is transferred to the heating plate 2. As a result, the water in the heating plate 2 is quickly changed to superheated steam at a predetermined temperature (for example, 200 ° C.) at a stretch, and is heated by the superheated steam supplied from the fluid outlet 7 through the pipe 14 into the heat treatment chamber 11. Since the heated object is cooked, the heated object can be cooked in a short time. In particular, since the superheated steam generating function and the heating cooking function are shared by the heating plate 2, the heating device can be made compact.

    In the first embodiment, the heating means 20 is separate from the heating plate 2, and maintenance of the heating means 20 and the heating plate 2 can be easily performed. In particular, since the heated member 21 made of a magnetic shunt alloy is used, temperature control is easy without providing an electric circuit, and the configuration is simple.

    Since the heating plate 2 is composed of an upper heating plate 2a and a lower heating plate 2b, and a groove constituting the fluid passage 3 is formed on the upper surface of the lower heating plate 2b, the production of the fluid passage is easy. Further, by removing the upper heating plate 2a, maintenance, that is, removal of deposits such as water scale and calcium compounds accumulated in the groove can be performed, so that the groove cleaning is easy.

(Embodiment 2)
FIG. 7 relates to the second embodiment, and parts different from those of the first embodiment are denoted by different reference numerals, this part will be described, and description of other components will be omitted. In the second embodiment, the heating plate 31 is an upper heating plate 31a and a lower heating plate 31b, and a fluid passage 33 is formed on the lower surface of the upper heating plate 31a. A magnetic shunt alloy is attached to the lower heating plate 31b. In the second embodiment, the fluid passage 33 gradually narrows (smoothly) as the passage width increases upward. As a result, the saturated water in the fluid passage 33 rises, and the fluid passes from the lower heating plate 31b. It is difficult to leave. Further, when the fluid passage 33 is formed integrally with the upper heating plate 31a by the molding die, the passage width of the fluid passage 33 is gradually narrowed upward as described above. This is advantageous in terms of releasability. Further, only the magnetic shunt alloy 32 can be exchanged, or only the fluid passage 33 can be exchanged, and the exchange can be easily performed at a low cost. Moreover, in this Embodiment 2, since a water guide groove can be formed on a flat plate, manufacture work becomes possible easily.

    The heating apparatus using superheated steam of the present invention is not limited to the structure of the above embodiment, but extends the superheated steam supply path to a position corresponding to the upper side or the side of the object to be heated, or a plurality of outlets. It may be provided.

    As the material of the heating plate, aluminum, copper, iron, stainless steel and the like can be used. However, since aluminum is excellent in thermal conductivity and lightweight, it is suitable as a compact food heating apparatus.

    Although the upper and lower heating plates of the heating plate are made of aluminum, the lower heating plate is necessary for heating the fluid passage, and the upper heating plate has little influence. Therefore, when it is not necessary to heat the heat treatment chamber with the heating plate, the upper heating plate may be made of heat resistant plastic or the like. In the above embodiment, since the fabrication is easy, the depth of the fluid passage is the same depth. However, in some cases, the fluid passage may be gradually deepened to allow volume expansion when becoming saturated steam. good.

    Although the fluid passage is formed integrally with the heating plate, it may be formed as a separate member such as an iron plate and attached integrally.

    The member to be heated 21 of the heating means is a magnetic shunt alloy plate embedded so that one surface is exposed on the heating plate, so that the structure is simple and the temperature control of the superheated steam is easy. However, since the magnetic shunt alloy is expensive, an electric heating means such as an electric cartridge heater, a cast-in heater, a hot plate heater, a halogen heater, or a radiant heater may be used in some cases.

    The heating device using superheated steam of the present invention is a method for thawing and baking foods such as meat, fish, bread, hamburger and dumplings, steamed cooking such as steamed rice and steamed rice bowl, food cooking such as cooking of soybeans, wood, It can be used for food drying, sterilization and disinfection of canned food, retort food, and medical equipment. Moreover, it can be used as cooking equipment in the food processing industry, the restaurant industry, etc. as an industry, and can also be used as a household cooking utensil.

It is the schematic of the heat processing apparatus concerning Embodiment 1 of this invention. It is a top view of the upper heating board concerning Embodiment 1 of the present invention. It is a figure explaining the width | variety of the fluid channel | path which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between a pressure loss and a saturated vapor conversion rate. 2 is a cross-sectional view of a fluid passage according to Embodiment 1. FIG. It is a rear view of a heating plate, and is a figure which shows the example of the attachment state of a magnetic shunt alloy. It is a figure which shows another structural example of the channel | path for fluids.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Superheated steam generator 2 Metal heating plate 3 Spiral fluid passage 4 Expanded diameter part 5 Water guide groove b1, b2 Passage width 10 Heat treatment device 11 Superheat treatment chamber 12 Housing 13 Water supply means 14 Superheated steam supply passage 20 Heating means

Claims (8)

A metal heating plate disposed in the lower part of the housing forming the superheat treatment chamber is heated by heating means disposed in the lower part of the heating plate, and the fluid flowing in the heating plate is heated from the superheated steam. A superheated steam generator that is heated up to
A spiral fluid passage formed in a substantially horizontal direction inside the heating plate;
A water introduction portion provided at a center portion of the spiral of the fluid passage of the heating plate;
A fluid outlet provided at the outer end of the spiral of the fluid passage of the heating plate;
The spiral fluid passage has a diameter-expanded portion formed by gradually increasing the passage width in the fluid passage from the water introduction portion toward the fluid outlet portion,
The water introduced from the water introduction part is superheated at a stretch by passing through the spiral fluid passage, and superheated steam is generated. The superheated steam generator according to claim 1,
The expanded diameter portion is provided until the water in the fluid passage changes from saturated water to gas-liquid two-phase flow to saturated steam,
From the downstream end of the enlarged diameter portion to the fluid extraction portion, the passage width of the downstream end of the enlarged diameter portion is formed to be the same as or slightly increased.
From the water introduction part to the upstream end part of the enlarged diameter part, it is formed to be the same as or slightly increased from the enlarged width of the enlarged diameter part. The superheated steam generator according to claim 1 or 2,
A water guide groove extending in the fluid passage direction is formed on the bottom surface of the enlarged diameter portion. The superheated steam generator according to claim 3,
The water guide grooves are provided in a plurality of rows in the passage width direction of the fluid passage. The superheated steam generator according to claim 3 or 4,
The water guide groove is formed in the latter half portion of the enlarged diameter portion. In the superheated steam generator according to any one of claims 1 to 5,
A heated member made of a magnetic shunt alloy is integrally attached to the lower surface side of the heating plate. A heat treatment apparatus using the superheated steam generator according to any one of claims 1 to 6,
A housing forming the overheat treatment chamber;
A metal heating plate that is disposed in the lower part of the housing and heat-treats the object to be heated set in the housing;
A water supply means connected to the water introduction part of the fluid passage and supplying water to the fluid passage;
A superheated steam supply path connected to the fluid take-out section and having a tip opened to the superheat treatment chamber;
Heating means for heating the heating plate, heating water in the fluid passage to generate saturated water, and further heating the saturated water to generate superheated steam via saturated steam;
It is characterized by providing. In the heat treatment apparatus using superheated steam according to claim 7,
The heating means includes a heated member made of a magnetic shunt alloy integrally attached to the lower surface side of the heating plate, and an electromagnetic induction heating member that electromagnetically heats the heated member.

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