JP2005098553A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger and a heat exchanging (heating) method capable of evenly heating the whole and improved in heat transmittance to a fluid by eliminating local heating of a fluid, especially a high viscous or uneven heating (heat exchanging) fluid such as a starch suspension, or restricting local heating at an extremely high ratio by supplying the only electromagnetism without using a heat medium such as steam. <P>SOLUTION: The heat exchanger is provided with a magnetic flux generating work coil connectable to a high frequency current generating means, a tubular housing having a flow passage for passing the fluid therethrough and formed from a material possible to be heated by electromagnetic induction of the work coil to exchange the heat between the fluid flowing in the flow passage, and an agitating element arranged inside the tubular housing to agitate the fluid passing through the flow passage. A heating method of eliminating local heating in the fluid or restricting it at an extremely high ratio to evenly heat the whole can be provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat exchanger (IH type heat exchanger) for heat exchange by heat exchange with a fluid, particularly a highly viscous fluid (for example, a starch suspension) using electromagnetic induction heating. .

  According to the present invention, it is possible to provide a heat exchanger with improved thermal conductivity to a fluid. In particular, when fluid that should be heat exchanged (heated) is selected, a fluid that is sensitive to temperature and locally thickens by heating to become a highly viscous fluid, that is, a fluid that is difficult to heat uniformly, such as a starch suspension. Even so, it can be easily heated by supplying only electromagnetism, and the whole fluid can be heated uniformly by eliminating or suppressing with high probability that such fluid is not locally heated. Can do.

  As a typical method of heat exchange for heating a fluid, there is a boiler method using steam as a heat medium. However, in the case of the boiler system, the installation area of the apparatus becomes large because the installation of a heat medium, fuel circulation equipment, etc. is required, the followability to load fluctuation is poor, the raw material due to the retention of drain and fluctuation of steam pressure There was a problem that the temperature was not stable and the heat exchanger was likely to become a pressure vessel because steam was used.

  On the other hand, many proposals have heretofore been made regarding heat exchangers that heat a fluid only by supplying electromagnetic or the like without using a heating medium such as steam (see, for example, Patent Documents 1, 2, and 3). ).

Japanese Patent Laid-Open No. 9-75948 JP-A-8-94176 Japanese Patent Laid-Open No. 5-129070

  For example, there is a report that an electromagnetic induction heating device that heats a fluid to a sterilization temperature can be provided (see Patent Document 1). However, in the reported electromagnetic induction heating apparatus, it is necessary to install a circulation facility such as fuel, which is a problem recognized in a heat exchanger that heats a fluid using a heating medium such as steam. In addition, the installation area of the device is increased, the followability to load fluctuation is poor, the temperature is not stable due to drain retention and fluctuation of steam pressure, etc. However, the heat transfer (heat conductivity) to fluids, particularly highly viscous fluids (especially starch suspensions), is insufficient. For this reason, when the temperature of the fluid rises, there is a problem that the rise is bad and the temperature is likely to be non-uniform. In addition, when the heat transferability is insufficient, the temperature of the housing heated by electromagnetic induction becomes higher than necessary, and there is a problem that the fluid is burnt due to local heating. Further, an agitating element is provided inside the heat exchanger to increase the thermal conductivity to the fluid, and a fluid, particularly a highly viscous or hardly uniform heatable fluid such as a starch suspension, is locally localized in the fluid. There is no description of a heat exchanger suitable for heating uniformly (overall heating) by eliminating or suppressing with extremely high probability that it is not heated (local heating).

  Therefore, the problem to be solved by the present invention is to provide a fluid, particularly a highly viscous or difficultly heated (heat exchange) fluid such as a starch suspension, by simply supplying electromagnetic power without using a heating medium such as steam. The heat exchanger and the heat exchange (heating which can be heated uniformly in the whole, eliminating local heating in the fluid or suppressing it with a very high probability, and heating the fluid uniformly. ) To provide a method and the like.

  According to the present invention, by using a heat exchanger having a specific configuration, uniform heating of a fluid, particularly a highly viscous or hardly uniform heating fluid such as a starch suspension can be achieved. This heat exchanger has a work coil for generating magnetic flux that can be connected to a high-frequency current generating means, and a flow path for passing a fluid, and is made of a material that can be heated by electromagnetic induction by the work coil. And a tubular housing for exchanging heat with the fluid passing therethrough. Furthermore, a stirring element for stirring the fluid passing through the flow path is provided (arranged) in the tubular housing (specifically, the flow path). That is, when a high frequency current is supplied to the work coil by the high frequency current generating means, the tubular housing is heated by electromagnetic induction by the work coil, that is, receives heat generated from the work coil and generates heat, and this tubular housing Due to the interaction with the stirrer element arranged inside, the temperature of the tubular housing heated, in particular by electromagnetic induction, decreases, so that there is no local heating in the fluid or is suppressed (reduced) with a very high probability, That is, uniform heating of the fluid is achieved. In addition, when the work coil is disposed on the tubular housing via a support member such as the spacer so that the inner surface of the tubular coil is spaced apart from the outer surface of the tubular housing, the work coil is heated by electromagnetic induction. It can suppress that it becomes more than heat-resistant temperature by the heat transfer from the made tubular housing, without attaching a heat insulating material. A plurality of baffle plates that are sequentially arranged in the axial direction inside the tubular housing as the agitating element and are twisted at a predetermined angle around the tube axis, the axial end portions of which are adjacent to each other. If a stirring element consisting of a baffle plate arranged crossing each other is selected, the fluid to be heated is sufficiently mixed, so that it can be easily heated uniformly at an appropriate temperature. Become. By controlling the high-frequency current to be applied and the flow rate of the fluid, uniform heating up to a predetermined (appropriate) temperature of the fluid to be heated is achieved while keeping the temperature of the tubular housing constant. Is done. Moreover, even when a highly viscous or difficult to heat uniform fluid such as a starch suspension is selected as the fluid, local heating in the fluid is eliminated or suppressed with a very high probability, and this is efficiently performed. Exchanges can be made.

That is, in the first aspect of the present invention, a work coil for generating magnetic flux that can be connected to high-frequency current generating means,
A tubular housing having a flow path for passing a fluid, made of a material capable of electromagnetic induction heating by the work coil, and exchanging heat with the fluid passing through the flow path;
Provided is a heat exchanger (hereinafter also referred to as “heat exchanger of the present invention”) provided with an agitating element that is disposed in the tubular housing and agitates a fluid passing through the flow path. be able to.

  Further, in the heat exchanger according to the present invention, the stirring element is a plurality of baffle plates that are sequentially arranged in the axial direction of the tubular housing and are twisted at a predetermined angle around the tube axis. It can be made of a baffle plate whose direction end portion is arranged to intersect with the end portion of the adjacent baffle plate.

  Furthermore, in the heat exchanger according to the present invention, a support member arranged to hold the work coil at a predetermined interval with respect to the outer surface of the tubular housing can be provided.

  In the heat exchanger of the present invention, the work coil can be arranged such that the inner surface thereof and the outer surface of the tubular housing have a predetermined distance. The predetermined interval is an optimum interval for giving efficient induction heating to the tubular housing at a predetermined temperature, but it is preferably 2 mm at the longest.

  The heat exchanger according to the present invention further includes means for controlling the applied high-frequency current and means for controlling the flow rate of the fluid, and controls the fluid to be uniformly heated to a predetermined temperature. be able to. This allows the fluid to be heated to be heated to a predetermined temperature while maintaining the tube wall (wall surface) in the tubular housing at a predetermined temperature, so that the fluid is not excessively heated. There is no or very high probability of local heating in the fluid. As a result, the fluid can be uniformly heated to an appropriate temperature.

  The heat exchanger of the present invention is suitable as a heat exchanger for highly viscous fluids (for example, starch suspensions), and even when such a fluid is selected, local heating in the fluid is performed. It can be eliminated or suppressed with a very high probability, and heat exchange with this can be performed efficiently.

In the second aspect of the present invention, the tubular housing is subjected to electromagnetic induction by a work coil for generating magnetic flux disposed through a support member so that the inner surface and the outer surface of the tubular housing are spaced apart from each other. From the tubular housing heated by heating and electromagnetic induction by the work coil, the temperature of the tubular housing is lowered and localized heating in the fluid is eliminated or suppressed with a very high probability in the tubular housing. A fluid heating method (hereinafter, also referred to as “heating method of the present invention”) including heating the fluid uniformly by causing the fluid to stir and flow with a stirring element provided to exchange heat. ) Can be provided.

  In the heating method of the present invention, the predetermined interval can be at most 2 mm.

  Furthermore, in the heating method of the present invention, even when the fluid is a highly viscous fluid (for example, a starch suspension), local heating in the fluid is eliminated or suppressed with a very high probability, Heat exchange can be performed efficiently with this.

  According to the heating method of the present invention, the flow rate of the fluid supplied into the tubular housing is controlled while controlling the temperature of the tube wall (wall surface) in the tubular housing by controlling the high frequency current to be applied. It is possible to control and maintain the temperature of the tubular housing constant, while controlling the fluid to be uniformly heated to a predetermined temperature by eliminating local heating or suppressing it with a very high probability. There is no adverse effect such as scorching the fluid to be burned.

  The present invention provides a heat exchanger with enhanced thermal conductivity to a fluid. This heat exchanger (the heat exchanger of the present invention) suppresses fluids, particularly highly viscous or difficultly heatable fluids such as starch suspensions, by eliminating local heating in the fluid or with extremely high probability. , It can be heated uniformly throughout. In this heat exchanger, the fluid to be heated can be heated only by supplying electricity, and supply equipment such as steam is unnecessary. Also, a fluid heating method for heating a fluid, particularly a highly viscous or hardly uniformly heatable fluid such as a starch suspension, in which the local heating in the fluid is eliminated or suppressed with a very high probability, and the fluid is uniformly heated as a whole. Can be provided.

  Furthermore, using the heat exchanger, a fluid that is uniformly heated, for example, a starch suspension that is uniformly pregelatinized can be produced continuously and easily. Therefore, the present invention is extremely useful industrially, particularly in the food field.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
The present invention includes a heat exchanger for heating a fluid passing through a flow path inside a tubular housing, preferably a highly viscous fluid such as a starch suspension, and the fluid (preferably a highly viscous fluid such as a starch suspension). A method of heating the fluid). In addition, although it demonstrates in detail using FIGS. 1-5 centering on the heat exchanger of this invention, this invention is not limited to this.

(Heat exchanger of the present invention)
In the heat exchanger of the present invention, the fluid (fluid to be heated) is heated at an excessive temperature (excessively), without causing adverse effects such as scorching, or local heating in the fluid is eliminated or extremely high. Suppressing with probability, it can be heated at an appropriate temperature and uniformly. In particular, a highly viscous fluid such as a starch suspension can be heated uniformly until a predetermined temperature is reached. That is, it is extremely excellent as a heat exchanger for heating a highly viscous fluid such as starch suspension.

  As a heat exchanger according to one embodiment of the present invention, for example, referring to FIGS. 1 and 2, stirring elements 1 and 6 are disposed inside tubular housings 2 and 7. Support members 3 and 8 are arranged on the outer surfaces of the tubular housings 2 and 7 so as to hold the work coils 4 and 10 for generating magnetic flux at a predetermined interval. Further, the work coils 4 and 10 have the same shape (cylindrical shape) as the tubular housings 2 and 7, and the inner surfaces (inner peripheral surfaces) of the work coils 4 and 10 and the outer surfaces of the tubular housings 2 and 7 ( The outer circumferential surface) is wound around the tubular housings 2 and 7 via the support members 3 and 8 so as to form a heat-insulating air layer 9. A flange 5 is disposed at the end of the tubular housing 2 so as to be fitted to the end. Although not shown in FIGS. 1 and 2, the work coils 4 and 10 are connected to high-frequency current generating means.

  Here, the agitating element is a mixing element (mixing element) disposed inside the tubular housing (specifically, its flow path), and causes the fluid to stir and flow in the tubular housing. Mixing is promoted by changing the relative positional relationship of the fluid in the tube cross-section by dividing and guiding each in different directions, i.e. swirl flow by increasing the fluid contact flow with the tube wall and elements of the tubular housing It has a structure to be made.

  As a heat exchanger according to one embodiment of the present invention, for example, referring to FIG. 3, a magnetic flux (magnetic field) 17 is generated from the work coil 12 in response to a high-frequency current applied by the high-frequency current generating means 15. Eddy currents are generated in the tubular housing that is the object to be heated so as to be orthogonal to the magnetic flux 17. Furthermore, Joule heat is generated by the eddy current and the electrical resistance of the tubular housing 11 (specifically, the material). At this time, the eddy current is larger as it is closer to the surface of the tubular housing 11 and exponentially decreases as it goes into the inside (skin effect), so that substantially only the surface of the tubular housing 11 is heated ( Fever).

  The shape and size of the tubular housing used in the present invention may be appropriately selected according to the type and amount of fluid to be heated (heat exchange) and the scale as a heat exchanger, and are not particularly limited.

  The material of the tubular housing is a material that can be heated by electromagnetic induction, that is, a material that is used as a heating element that generates heat when an electromagnetic method is applied when heated by an electromagnetic method such as application of a high-frequency current. Well, there are no particular restrictions. Specifically, for example, stainless steel exhibiting magnetism such as SUS430 can be used. In addition, SUS304, SUS316, etc. are non-magnetic in the solution heat treatment state, but they are usually processed even if they are non-magnetic, such as stainless steel that becomes magnetic when it becomes a martensitic structure by cold working. Therefore, a material exhibiting magnetism can also be used.

  There is no restriction | limiting in particular about the shape and magnitude | size of the said flow path, According to the kind and quantity of the fluid which should be heated (heat exchange), the scale as a heat exchanger, etc., it selects suitably.

  In this invention, the said flange can be arrange | positioned so that it may fit with this edge part only in the both ends of the said tubular housing, or one edge part of the said tubular housing. That is, the flange is not limited as long as it can be disposed so as to be fitted to both ends of the tubular housing or only one end of the tubular housing. No.

  Accordingly, the shape and size of the flange are not particularly limited, and may be appropriately selected according to the shape and size of the tubular housing to be disposed.

  The flange is provided with an opening so as to be fitted to one or both ends of the tubular housing. The shape and size of the opening are appropriately selected according to the shape and size of the tubular housing.

  As for the stirring element used in the present invention, as described above, the fluid flow is divided and each is guided in a different direction, thereby changing the relative positional relationship of the fluid in the pipe cross section and promoting mixing. For example, a mixing element having no movable part installed in a pipe of a static type pipe stirrer (static mixer) can be used. Specifically, for example, a spiral element having a torsional blade obtained by twisting a plate-like body around the central axis in the longitudinal direction, or a member having a plate-like body twisted by a predetermined angle An element having a structure in which one or a plurality of (baffle plates) are connected can be used. In particular, in the present invention, elements described in Japanese Patent Publication No. 1-31928 are preferably used. As an agitation element used in a heat exchanger according to an embodiment of the present invention, for example, referring to FIG. 4, the elements are sequentially arranged in the axial direction inside the tubular housing 20 in the tubular housing 20. A plurality of baffle plates twisted at a predetermined angle around the tube axis, the end portions in the axial direction being made of baffle plates arranged to intersect with the end portions of the adjacent baffle plates ( The mixing element described in Japanese Patent Publication No. 1-31928 is provided.

  The stirring element does not need to be heated by electromagnetic induction as described above. Therefore, the material is not particularly limited, and may or may not be a material that can be heated by electromagnetic induction. For example, a material such as SUS304, SUS316, or SUS430, or a nonmagnetic material such as ceramic or resin can be selected.

  In the present invention, the form of the support member is not particularly limited, and for example, a spacer, a pin, and the like are selected.

  Further, as the material of the support member, a material having a low thermal conductivity, for example, ceramic, heat resistant resin, or the like can be selected so that heat of the tubular housing is not transmitted to the work coil.

  Further, as to the shape and size of the support member, as will be described later, the inner surface of the work coil and the outer periphery of the tubular housing can have a predetermined interval, that is, the inner surface of the work coil, A heat insulating air layer is selected between the outer periphery of the tubular housing. The predetermined interval may be an optimal interval to provide efficient induction heating at a predetermined temperature for the tubular housing, but preferably 2 mm at the longest. Thus, by taking a predetermined distance, it can suppress that the said work coil becomes more than heat-resistant temperature by the heat transfer of the tubular housing heated by the electromagnetic induction. Further, a heat insulating air layer is provided (configured) between the inner surface of the work coil and the outer periphery of the tubular housing, that is, without providing a heat insulating material such as a conventional ceramic fiber, the air layer is used as a heat insulating material. Because it is provided, it is necessary to select and arrange the work coil winding method and the number of turns according to the selected heat insulating material, and solve problems such as a difference in performance due to differences in the work coil winding method and the number of windings. be able to.

  In addition, about the said supporting member, two or more are arrange | positioned in a suitable position according to the form. For example, when a pin is selected as the support member, a plurality of pins are arranged at appropriate positions on the outer periphery in the axial direction of the tubular housing.

  There is no restriction | limiting in particular about the fixing method of the said supporting member, A general fixing method is selected. For example, it can be fixed by a method of fixing by welding or the like, or a method of fixing the work coil by embedding other than its terminal portion in a resin (as a resin mold) and fitting it in this resin.

  There is no restriction | limiting in particular about the fixing method of the said element for stirring. For example, a method of fixing the stirring element to the tubular housing by welding or the like, a locking part provided at an appropriate position on the outer periphery of the tubular housing, and a locking part provided at an appropriate position of the stirring element; A general fixing method such as a method of holding and fixing a ring by a predetermined ring is selected.

  In the adiabatic air layer, it is preferable to create an air flow. As this method, a method of creating a flow of air using a cooling fan or the like is selected.

  In the present invention, any material that can be used as a conductor such as copper or an alloy thereof that generates a magnetic flux (magnetic field) by receiving a high-frequency current can be used without particular limitation.

  There is no restriction | limiting in particular about the thickness of the said work coil. Moreover, there is no restriction | limiting in particular also about the length, According to the shape of the said tubular housing, a magnitude | size, etc., it selects suitably.

  In the present invention, the work coil is disposed on the tubular housing such that an inner surface thereof and an outer periphery of the tubular housing have a predetermined interval. At this time, the work coil can be wound and arranged in accordance with the shape of the tubular housing. When the work coil generates a magnetic flux, an eddy current is perpendicular to the magnetic flux and the tubular housing. The work coil may be formed and arranged in an appropriate shape so as to occur on the surface (specifically, its surface). For example, according to the shape of the tubular housing, for example, when the tubular housing is cylindrical, it can be wound and arranged to form a cylindrical shape (solenoid). In addition, one or a plurality of work coils formed in an appropriate shape in advance can be arranged corresponding to the shape of the tubular housing. As described above, the inner surface of the work coil and the outer periphery of the tubular housing are arranged at a predetermined interval via the support member. The predetermined interval may be an optimal interval to provide efficient induction heating at a predetermined temperature for the tubular housing, but preferably 2 mm at the longest.

  As the work coil, a coil (resin mold) in which a portion other than the terminal portion is embedded in a resin can be used. By doing so, the number of turns of the work coil can be made constant. As the resin, an insulating resin such as a thermosetting resin added with an inorganic filler is selected.

  The heat exchanger according to the present invention further comprises means for controlling the applied high-frequency current in order to keep the temperature of the tubular housing constant and to prevent the fluid from being locally heated or to suppress it with a very high probability. In addition, by providing means for controlling the flow rate of the fluid, for example, means for fluidly transferring the fluid (fluid transfer means), the fluid is uniformly heated to an appropriate temperature without excessive heating. Can do.

  As a heat exchanger according to an embodiment of the present invention, for example, referring to FIG. 5, a work coil 26 is formed in the tubular housing 24 in the same shape (cylindrical shape) as the tubular housing 24. 26 through a support member (not shown) so that the inner surface (inner peripheral surface) of 26 and the outer surface (outer peripheral surface) of the tubular housing 24 have a predetermined distance, that is, form a heat insulating air layer. It is wound. The work coil 26 is connected to a high-frequency current generating means 28 by a wiring 27. The high frequency current generated from the high frequency current generating means 28 acts on (applies to) the work coil 26 to generate a magnetic flux. In response to this magnetic flux, the tubular housing 24 generates heat. That is, the workpiece coil 26 is heated by electromagnetic induction. Furthermore, a stirring element 29 is disposed in the flow path inside the tubular housing 24. On the other hand, the fluid storage tank and the tubular housing 24 are connected via a pipe so that the fluid is led out from a fluid storage tank (tank storing the fluid) (not shown). The flow path and the piping are in communication. The pipe connecting the fluid reservoir and the tubular housing 24 is provided with means (fluid transfer means) 30 for quantitatively transferring the fluid into the tubular housing 24. The fluid is transferred to the inside of the tubular housing 24 at a predetermined flow rate by the fluid transfer means 30 and passes through the flow path inside the tubular housing 24. At this time, the fluid contacts the inner wall (wall surface) of the tubular housing 24 that generates heat by the magnetic flux generated from the work coil 26, so that the fluid exchanges heat with them, that is, is heated. At the same time, the fluid is stirred by the specific structure (shape) of the stirring element 29. As a result, the whole fluid is uniformly heated. In addition, the heat transfer coefficient increases due to the stirring at this time, and as a result, the temperature of the tubular housing 24 decreases, and there is no local heating in the fluid or it is suppressed with a very high probability.

  There is no restriction | limiting in particular about the fluid used in this invention, According to the objective, it selects. For example, a source, dressing, oil, highly viscous fluid, etc. are selected. The “highly viscous” fluid applicable in the present invention is, for example, a fluid having a viscosity of at most 50000 cP (50000 cP or less), in particular, about 1 to 10000 cP. Specific examples of such fluids include starch suspensions. In the present invention, the temperature can be easily adjusted by controlling the high-frequency current applied as described later, and the flow rate of the fluid to be heated can be adjusted. This method can also be applied to the case of heating the fluid.

  In the present invention, the high-frequency current generating means is not particularly limited, and for example, a known high-frequency current generator such as an inverter can be used. In general, the high frequency current generating means has a function of controlling the magnitude of the high frequency current to be applied (generated).

  In the present invention, the temperature of the tube wall in the tubular housing can be easily adjusted (controlled) by controlling the high-frequency current applied by the high-frequency current generating means. The conditions at this time may be selected according to the type of fluid to be heat exchanged (fluid to be heated), the flow rate thereof, and the like. For example, when a starch suspension at 20 ° C. is selected as the fluid to be heated and supplied to the flow path inside the tubular housing at 50 kg / H, a power source of 5 to 6 kw is supplied by the high-frequency current generating means. The high frequency current generated by the conversion can be about 110 to 128 ° C.

  In the present invention, as means for controlling the flow rate of the fluid, for example, fluid transfer means can be provided as described above. The fluid transfer means is not particularly limited, and a known liquid transfer metering pump or the like that can be developed in the future can be used.

  The arrangement position of the fluid transfer means is determined according to the fluid transfer means to be selected. For example, when a suction type liquid transfer metering pump is selected as the fluid transfer means, it can be arranged downstream of the tubular housing, while an extrusion type liquid transfer metering pump is selected. In this case, it can be disposed upstream of the tubular housing.

  About the heat exchanger of this invention, one or more can be connected in series or in parallel and used. By doing so, the present invention can be applied even when a large amount of heat is required, such as when heating a large amount of fluid or a highly viscous fluid.

  In the heat exchanger of the present invention, other means such as a cleaning means for cleaning pipes, a temperature measuring means (thermocouple, etc.), a valve for adjusting the flow rate of fluid, etc. may be provided. Such a heat exchanger can also be included in the heat exchanger of the present invention.

(Heating method of the present invention)
According to the heating method of the present invention, the tubular housing is heated by electromagnetic induction by a work coil for generating magnetic flux disposed through a support member so that the inner surface of the tubular housing and the outer surface of the tubular housing have a predetermined distance. In addition, the tubular housing heated by electromagnetic induction by the work coil is disposed in the tubular housing to lower the temperature of the tubular housing and to eliminate or suppress the local heating in the fluid with a very high probability. It includes heating the fluid uniformly by causing the fluid to stir and flow with the stirring element to exchange heat. Therefore, for example, other steps such as a washing step for washing a pipe or the like through which the fluid passes can be added, and such a heating method can be included in the heating method of the present invention.

  The heating method of the present invention can be easily carried out with reference to the description in the heat exchanger of the present invention. In addition, according to the heating method of the present invention, the fluid is heated at an unnecessarily high temperature, without adverse effects such as scorching, and local heating in the fluid is eliminated or suppressed with a very high probability. It can be heated uniformly at a temperature of. In particular, a highly viscous fluid such as a starch suspension can be heated uniformly until a predetermined temperature is reached.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not restrict | limited at all by this Example and a comparative example.

[Example 1] Heating of fluid-1
FIG. 6 is a cross-sectional view schematically showing a heat exchanger (product of the present invention) according to an embodiment of the present invention. At both ends of the tubular housing (bore diameter (inner diameter) 47.8 mm, length 1350 mm) 35, flanges 36 corresponding thereto are disposed so as to be fitted to the ends, and the flow inside the tubular housing 35 is determined. An agitating element 40 is disposed in the path. Further, the work coil 37 has the same shape (cylindrical shape) as the tubular housing 35 in the tubular housing 35, and the inner surface (inner peripheral surface) of the work coil 37 and the outer surface (outer peripheral surface) of the tubular housing 35. ) Is wound through a spacer (not shown) so as to be about 2 mm. Further, the work coil 37 is connected to an inverter 39 which is a high-frequency current generating means by a wiring 38. Further, the tubular housing 35 is connected to a starch suspension storage tank (not shown) via a pipe, and fluid transfer means is disposed in the pipe. Using this heat exchanger, the starch suspension (20 ° C.), which is a fluid, was heated (α-ized) by the following method to produce a starch suspension at the target temperature (110 ° C.). In addition, the MONO pump 41 was used as a fluid transfer means.

(Fluid heating)
(1) A starch suspension at 20 ° C. was introduced as a fluid into a storage tank (not shown).
(2) A 5 kw power source was converted into a high-frequency current by the inverter 39 and applied to the work coil 37. As a result, the metal surface temperature inside (inner wall) of the tubular housing 35 was 150 ° C. on average.
(3) The starch suspension at 20 ° C. was transferred and supplied from the storage tank to the inside of the tubular housing 35 by the Morno pump 41 at a flow rate of 50 kg / H.
(4) The starch suspension transferred and supplied to the inside of the tubular housing 35 in (3) is allowed to pass through the flow path inside the tubular housing 35 and is agitated while contacting the inner wall of the tubular housing 35. Was heated (alpha).
(5) The heated (pregelatinized) starch suspension obtained in (4) was transferred and supplied to a storage tank (not shown) by the MONO pump 41.

[Comparative Example 1] Heating fluid-2
FIG. 7 is a cross-sectional view schematically showing a heat exchanger (IH heating type empty pipe: comparative product 1) according to a comparative example. At both ends of the tubular housing (caliber (inner diameter) 47.8 mm, length 1350 mm) 49, flanges 46 corresponding thereto are arranged so as to be fitted to the ends. Further, the work coil 47 has the same shape (cylindrical shape) as the tubular housing 49, and the inner surface (inner peripheral surface) of the work coil 47 and the outer surface (outer peripheral surface) of the tubular housing 49. ) Is wound through a spacer (not shown) so as to be about 2 mm. Further, the work coil 47 is connected by a wiring 50 to an inverter 48 that is a high-frequency current generating means. Further, the tubular housing 49 is connected to a starch suspension storage tank (not shown) via a pipe, and fluid transfer means is disposed in the pipe. Using this heat exchanger, the starch suspension (20 ° C.), which is a fluid, was heated (α-ized) by the following method to produce a starch suspension at the target temperature (110 ° C.). In addition, the MONO pump 51 was used as a fluid transfer means.

(Fluid heating)
(1) A starch suspension at 20 ° C. was introduced as a fluid into a storage tank (not shown).
(2) A 5 kw power source was converted into a high-frequency current by the inverter 48 and applied to the work coil 47. As a result, the metal surface temperature inside (inner wall) of the tubular housing 49 was 300 ° C. on average.
(3) The starch suspension at 20 ° C. was transferred and supplied from the storage tank to the inside of the tubular housing 57 by the Morno pump 51 at a flow rate of 50 kg / H.
(4) The starch suspension transferred and supplied to the inside of the tubular housing 49 in (3) passes through the flow path inside the tubular housing 49 and is brought into contact with the inner wall of the tubular housing 49 (heating). did.
(5) The heated (pregelatinized) starch suspension obtained in (4) was transferred and supplied to a storage tank (not shown) by the MONO pump 51.

Comparative Example 2 Fluid Heating-3
FIG. 8 is a cross-sectional view schematically showing a heat exchanger according to a comparative example (boiler heat exchanger: comparative product 2). At both ends of the tubular housing (caliber (inner diameter) 47.8 mm, length 2000 mm) 56, flanges 57 corresponding thereto are disposed so as to be fitted to the ends, and the flow inside the tubular housing 56 is determined. An agitating element 60 is disposed in the path. The tubular housing 56 is provided in a holding tube 58 having the same shape (cylindrical shape). Further, a steam passage 59 is formed between the inner surface (inner peripheral surface) of the holding tube 58 and the outer surface (outer peripheral surface) of the tubular housing 56 so that steam as a heat medium flows. Steam is supplied into the holding pipe 58 from a heat medium supply port (not shown) and discharged from a heat medium discharge port (not shown). The tubular housing 56 is connected to a starch suspension storage tank (not shown) via a pipe, and fluid transfer means is disposed in the pipe. Using this heat exchanger, the starch suspension (20 ° C.), which is a fluid, was heated (α-ized) by the following method to produce a starch suspension at the target temperature (110 ° C.). In addition, the MONO pump 61 was used as a fluid transfer means.

(Fluid heating)
(1) A starch suspension at 20 ° C. was introduced as a fluid into a storage tank (not shown).
(2) Steam of 3 kg / cm ² G is used as a heat medium in the passage 59 between the inner surface (inner peripheral surface) of the holding tube 58 and the outer surface (outer peripheral surface) of the tubular housing 56. (Not shown) was supplied into the holding tube 58 at 8 kg / H and discharged from a heat medium outlet (not shown). As a result, the metal surface temperature inside (inner wall) of the tubular housing 56 was 143 ° C.
(3) The starch suspension at 20 ° C. was transferred and supplied from the storage tank to the inside of the tubular housing 56 by the Mono pump 61 at a flow rate of 50 kg / H.
(4) The starch suspension transferred and supplied to the inside of the tubular housing 56 in (3) is allowed to pass through the flow path inside the tubular housing 56 and contact the inner wall of the tubular housing 56 and the stirring element 60. This was heated (alpha-ized) by stirring.
(5) The heated (pregelatinized) starch suspension obtained in (4) was transferred and supplied to a storage tank (not shown) by the MONO pump 61.

[Example 2] Evaluation of various heat exchangers The heat exchangers of Example 1 and Comparative Examples 1 and 2 were evaluated, i.e., when the starch suspension was gelatinized.
(Evaluation results)
When comparing the heat exchangers of Example 1 and Comparative Example 1, the starch suspension heated in the heat exchanger of Comparative Example 1 is the temperature of the inner wall (wall surface) of the tubular housing in the heat exchanger of Example 1. Compared to the above, since the temperature (metal surface temperature) of the inner wall of the tubular housing in the heat exchanger of Comparative Example 2 was higher, the starch suspension could be burned on the inner wall. On the other hand, when the heat exchangers of Example 1 and Comparative Example 2 were compared, the starch suspensions heated in the heat exchangers of Example 1 and Comparative Example 2 were all good. However, compared with the heat exchanger of Example 1, the scale of the heat exchanger of Comparative Example 2 was increased.

  From the above, it can be seen that in the heat exchanger of the present invention, the thermal conductivity to the fluid is enhanced, and there is no local heating in the fluid or is suppressed with a very high probability, and the entire fluid is heated uniformly. From this, it is clear that such a heat exchanger is excellent in uniformly heating a fluid, in particular, a highly viscous fluid such as a starch suspension. Therefore, according to the present invention, it is possible to provide a heat exchanger that uniformly heats a fluid, particularly a highly viscous fluid.

FIG. 1 is a perspective view schematically showing a heat exchanger according to one embodiment of the present invention. An agitation element 1 is disposed in a flow path inside the tubular housing 2. FIG. 2 schematically shows a view when the cross section in the AA ′ direction in FIG. 1 is viewed. An insulating air layer 9 is formed between the work coil 10 and the tubular housing 7. FIG. 3 is a perspective view schematically showing an induction heating method in the heat exchanger according to one embodiment of the present invention. In response to the high frequency current, a magnetic flux (magnetic field) 17 is generated from the work coil 12, and an eddy current is generated so as to be orthogonal to the magnetic flux 17. FIG. 4 is a cross-sectional view schematically showing a stirring element used in a heat exchanger according to one embodiment of the present invention. The stirring element includes a left twist baffle plate 21 and a right twist baffle plate 22. FIG. 5 is a cross-sectional view schematically showing a heat exchanger according to one embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing a heat exchanger according to an embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing a heat exchanger (comparative product 1) according to a comparative example. FIG. 8 is a cross-sectional view schematically showing a heat exchanger (comparative product 2) according to a comparative example. The tubular housing 56 is provided in a holding tube 58 having the same shape (cylindrical shape) as this, and steam flows through a gap 59 between the holding tube 58 and the tubular housing 56.

Explanation of symbols

1, 6, 13, 29, 40, 60. Stirring element 2, 7, 11, 20, 24, 35, 49, 56. Tubular housing 3, 8, 14. Support member 4, 10, 12, 26, 37, 47. Work coil 5, 25, 36, 46, 57. Flange 9. Insulated air layer 21. 21. Left twist baffle plate Right-twisted baffle plate 23, 34. Heat exchanger 15, 28, 39, 48. High-frequency current generating means 16, 27, 38, 50. Wiring 17. Magnetic flux 18. 18. Direction of eddy current flow Direction in which high-frequency current flows 31, 42, 52, 62. Fluid introduction direction 33, 44, 54, 64. Fluid outlet direction 30, 41, 51, 61. Fluid transfer means 32, 43, 53, 63. Piping 45. Heat exchanger (Comparative product 1)
55. Heat exchanger (Comparative product 2)
58. Retaining tube 59. Steam passage

Claims (7)

A work coil for generating magnetic flux that can be connected to high-frequency current generating means;
A tubular housing having a flow path for passing a fluid, made of a material that can be heated by electromagnetic induction by the work coil, and exchanging heat with the fluid passing through the flow path;
A heat exchanger comprising: an agitating element disposed in the tubular housing and agitating a fluid passing through the flow path.   The stirrer element is a plurality of baffle plates that are sequentially arranged in the axial direction of the tubular housing and twisted by a predetermined angle around the tube axis, the ends of which are adjacent to each other in the axial direction. The heat exchanger according to claim 1, comprising a baffle plate arranged so as to cross each other.   Furthermore, the heat exchanger of Claim 1 or 2 provided with the supporting member distribute | arranged so that the said work coil may be hold | maintained at predetermined spacing with respect to the outer surface of the said tubular housing.   The work coil is arranged such that an inner surface thereof and an outer surface of the tubular housing have a predetermined interval, and the predetermined interval is an optimum interval to provide efficient induction heating at a predetermined temperature with respect to the tubular housing. The heat exchanger as described in any one of Claims 1-3.   Furthermore, it comprises means capable of controlling the high-frequency current to be applied and means for controlling the flow rate of the fluid, and the fluid is prevented from being heated locally or suppressed with a very high probability, so as to have a predetermined temperature. The heat exchanger as described in any one of Claims 1-4 controlled so that it may heat uniformly. Heating the tubular housing by electromagnetic induction by a work coil for generating magnetic flux disposed through a support member so that the inner surface and the outer surface of the tubular housing are spaced apart from each other by the tubular housing, and by the work coil From the tubular housing heated by electromagnetic induction, the temperature of the tubular housing is lowered and the fluid is agitated by an agitating element disposed in the tubular housing so as to eliminate or extremely highly suppress local heating in the fluid. A fluid heating method comprising heating the fluid uniformly by flowing and exchanging heat.   Furthermore, the fluid is locally heated by controlling the flow rate of the fluid supplied into the tubular housing while controlling the temperature of the tube wall in the tubular housing by controlling the high frequency current to be applied. The method of heating a fluid according to claim 6, further comprising: controlling the uniform heating to a predetermined temperature by eliminating or suppressing with a very high probability.

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