JP2006054093A - Continuous energization heating device for high viscosity fluid food - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device using circular electrodes, electrically heating a high viscosity fluid food material while making the food continuously flow through a pipe passage, of which unevenness of heating temperature in a radial direction of the pipe passage is restrained, spark and scaling are prevented, deterioration of food quality is prevented, and a life of the electrode is prolonged. <P>SOLUTION: A length L of the circular electrodes in a longitudinal direction is set longer than R/2, preferably longer than R, an inner diameter of the circular electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a food material having fluidity that can be continuously fluidly transferred in a pipe, such as a liquid food material, a solid-liquid mixed food material, a gel food material, etc., and has a viscosity of 100 cP or more, preferably 1000 cP. The present invention relates to an apparatus for energizing and heating the above-described high-viscosity fluid food material while continuously flowing and transferring in a pipe (in a pipe) for sterilization and cooking.

  One method of heating a fluid food material for sterilization, cooking, etc. is to continuously flow the fluid food through the pipe by the pressure of a pump, etc. There is a method of heating. In this way, according to the method of continuously heating the fluid food material while continuously flowing and transporting the inside of the pipe, the food material continuously heated in the pipe can be continuously filled in the container as it is. The operation from heating to filling can be completely continuous.

  Conventionally, as described above, as a method for continuously heating a food material that is continuously flow-transferred in a pipe, the heating is performed by directly energizing the food material using the electrical resistance of the food material. A method using (Joule heating) has been put into practical use. An apparatus for continuously heating a fluid food material that continuously flows in a pipe by applying electric heating in this way has already been proposed in Patent Document 1, for example.

  In the apparatus of Patent Document 1, the food material flowing in the pipe line is provided in at least two parts at a predetermined interval from the upstream side to the downstream side of the pipe line, and in at least a part corresponding to the inner surface of the pipe line. An annular electrode (annular electrode) made of a conductive material is provided so as to surround, and a current is passed between the annular electrode on the upstream side and the annular electrode on the downstream side of the food material flowing in the pipeline. It is supposed to be heated and continuously energized and heated.

  In this case, as the annular electrode, Ti (titanium) or a Ti alloy is usually used from the viewpoint of food hygiene, corrosion resistance, durability, and the like, and the energization current is a high frequency current of about 1 kHz to 50 kHz. Is often used.

Japanese Patent Publication No. 5-33024

  In the continuous energization heating apparatus using the annular electrode as shown in Patent Document 1, the fluid food material is heated not by heat transfer from the outside but by resistance heat generation of the fluid food material itself flowing in the pipe. Therefore, in principle, the temperature of the flowable food material should rise uniformly, and heating temperature unevenness should not occur. In practice, however, heating temperature unevenness often occurs in the pipe line, and it has been found that heating temperature unevenness is likely to occur and its adverse effect is particularly great when heating a highly viscous fluid food material.

  That is, the temperature rise of the flowable food material due to energization heating is large in the portion near the inner wall in the pipeline, while the portion of the flowable food material in the portion far from the inner wall of the pipeline (particularly near the central axis position in the pipeline). The temperature rise is reduced, so that temperature unevenness occurs in the radial direction in the pipe. The cause of such a phenomenon is not necessarily clear, but it is thought that it occurs because the current density distribution in the pipe radial direction in the current flowing between the upstream annular electrode and the downstream annular electrode is not uniform. . That is, the length of the path of the current flowing between the upstream annular electrode and the downstream annular electrode is the shortest near the pipe wall, while the current path flowing through the central axis position in the pipe is relatively long. Therefore, the current density tends to increase due to the concentration of current near the inner wall of the pipeline, while the current density tends to decrease at the central axis position, and therefore the current density distribution in the radial direction in the pipeline is uneven. This is considered to cause heating unevenness. Here, when a fluid food material having a low viscosity (watery) is heated, the fluid food material is in a state of being stirred to some extent while flowing in the pipe. As a result, an almost uniform temperature rise is obtained, and thus uneven heating is not a problem. However, in the case of a fluid food material having a high viscosity, there is almost no disturbance between the upper and lower annular electrodes. There is no flow, so that heating unevenness appears directly as temperature increase unevenness.

  Here, the temperature unevenness as described above becomes extremely large and the temperature of the portion near the inner wall of the pipe line becomes remarkably high. The temperature of the annular electrode located on the inner surface of the pipe line also becomes high. Means that. If the temperature of the inner surface of the annular electrode becomes extremely high in this way, scaling (burning of the fluid food material) may occur at that part, or bumping may occur in the fluid food material and an electrical spark may occur. Thus, not only the maintenance, inspection, and cleaning of the annular electrode is increased, but also the life of the annular electrode is shortened, which may increase the cost.

  In addition, if the fluid food material is overheated near the inner wall of the pipe line (particularly near the inner surface of the annular electrode) as described above and scaling or sparking occurs, the quality of the fluid food material deteriorates, for example, aroma, color, taste There is a problem that causes deterioration of the scale and contamination of the scale.

  Particularly in continuous energization heating for a fluid food material having a high viscosity, the fluid food material having a high viscosity flowing in the flow path is located at a position along the inner surface of the pipe line (therefore, a position along the inner surface of the annular electrode). Due to viscous resistance to the inner surface of the pipeline, the flow velocity is usually slower than the central position in the pipeline, so the temperature of the fluid food material flowing in the pipeline is the temperature at the location along the inner surface of the pipeline. This tends to be higher than the center position in the pipe, and thus promotes the heating temperature unevenness as described above.

  In addition, in the case of electric heating, the flowable food material usually has a lower electrical resistance and an increased current value as the temperature rises, and it tends to generate heat. Therefore, the flowable food material tends to generate heat near the inner surface of the pipe. If the temperature of the material rises, the current value accompanying the increase in the temperature increases the temperature of the fluid food material near the inner surface, and as a result, the heating temperature unevenness becomes remarkable.

  Therefore, in combination with these factors, in the heating of fluid food materials using an annular electrode, particularly in the heating of fluid food materials with high viscosity, the heating temperature unevenness in the pipe line becomes large, and the aforementioned It often caused such problems.

  This invention was made against the background described above, and in a continuous energization heating method using an annular electrode for a fluid food material having a high viscosity, the occurrence of uneven heating temperature of the fluid food material in the pipeline is suppressed. Accordingly, it is an object of the present invention to provide an apparatus in which the quality deterioration of the fluid food material as described above, the life of the annular electrode, and problems in maintenance are not caused.

  In order to solve the problems as described above, the present inventors have found that the heating temperature unevenness in the pipe line during energization heating of the highly viscous fluid food material using the annular electrode, the current heating conditions and the annular electrode As a result of repeated experiments and examinations on the relationship between the shape and dimensions of the tube, the dimensions of the annular electrode, especially its width (width in the direction along the length of the conduit), and the inner diameter of the annular electrode (usually The same as the inner diameter of the pipe) is closely related to the occurrence of temperature unevenness in the radial direction of the pipe, and when further experiments and examinations were conducted, the width L of the annular electrode was increased. When the fluidity food material having a high viscosity of 100 cP or more, particularly 1000 cP or more is heated by setting the width L to R / 2 or more, preferably R or more, with respect to the inner diameter R of the annular electrode. However, to the extent that temperature irregularities do not interfere Found that can win, it was able to complete the present invention.

  Specifically, the continuous energization heating device for the high-viscosity flowable food material according to the first aspect of the present invention is provided with at least two portions at predetermined intervals from the upstream side to the downstream side of the pipeline. An annular electrode is provided so as to be concentric with the central axis, and a fluid food material having a high viscosity of 100 cP or more is continuously fluidized and transferred in the length direction in the pipe, and adjacent annular In the continuous energization heating device for high-viscosity flowable food material for energizing and heating the high-viscosity flowable food material by passing a high-frequency current having a frequency in the range of 1 to 50 kHz between the electrodes, The dimension of the width L of the electrode in the pipe length direction is set to R / 2 or more with respect to the inner diameter dimension R of the annular electrode.

  Moreover, the continuous electric heating apparatus of the high-viscosity fluid food material according to the invention of claim 2 is the continuous electric heating apparatus of the high-viscosity fluid food material according to claim 1, wherein The dimension of the width L is set to a dimension equal to or larger than the inner diameter dimension R of the annular electrode.

  Furthermore, the continuous energization heating device for the high-viscosity flowable food material according to claim 3 is the continuous energization heating device for the high-viscosity flowable food material according to claim 1 or 2, wherein the pipe line in each annular electrode The dimension of the width L in the length direction is set to a dimension not more than three times the inner diameter dimension R of the annular electrode.

  And the continuous-current heating apparatus for high-viscosity fluid food material according to the invention of claim 4 is the continuous-current heating apparatus for high-viscosity fluid food material according to any one of claims 1 to 3, wherein the viscosity is 1000 cP. This is for energizing and heating the above fluid material.

  In this specification, the viscosity of 100 cP or more, or 1000 cP or more means the viscosity at 20 ° C.

  According to the continuous energization heating apparatus of the present invention, when heating a fluid food material having a high viscosity of 100 cP or more, particularly 1000 cP or more, the heating temperature unevenness in the radial direction in the pipe is suppressed as much as possible. Reduces the quality of food materials by preventing overheating, scaling and sparking of food materials, reducing maintenance, inspection and cleaning, extending electrode life, operating costs and manufacturing Costs can be reduced.

  FIG. 1 and FIG. 2 show an example of the continuous energization heating device of the present invention.

  In FIG. 1 and FIG. 2, the pipe line 1 for partitioning the flow path 2 through which the flowable food material 3 flows is made into a pipe shape having a circular cross section. And this pipe line 1 arranges a plurality of cylindrical pipe wall members 5 made of an electrically insulating material such as a synthetic resin along the axial direction, and, for example, Ti or Ti alloy between each of the pipe wall members 5 A plurality of (three in the illustrated example) annular electrodes 7A, 7B, and 7C made of a conductive material such as the like are arranged. Accordingly, the annular electrodes 7A, 7B, and 7C are provided at predetermined intervals in the length direction of the pipe line 1 (flow direction of the flowable food material), and the flowable food material that flows through the pipe line 1 respectively. 3 will be surrounded.

  A high frequency voltage having a frequency of 1 to 50 kHz is applied to the electrodes 7A, 7B, and 7C from the high frequency electrode 9 via the power supply controller 11 in opposite phases. And if the fluid food material 3 is continuously flowed in the pipe line 1 and a high frequency voltage is applied between the electrodes 7A-7B and 7B-7C, the fluid food is produced between the electrodes 7A-7B and 7B-7C. A high frequency current flows through the material 3, whereby the fluid food material 3 generates heat. That is, the fluid food material 3 is continuously heated in the pipe 1.

Here, in the case of the current heating device of the present invention, the width L in the length direction (flowing direction of the flowable food material) of the pipe line 1 in each annular electrode 7A, 7B, 7C is set to each annular electrode 7A, 7B, 7C. For the inner diameter R of
L ≧ R / 2
It is determined that Thus, by setting the width L of each annular electrode 7A, 7B, 7C to R / 2 or more, the heating temperature unevenness of the fluid food material in the pipe line 1 can be suppressed.

  That is, in a continuous energization heating apparatus using a conventional annular electrode, the width L of the annular electrode is usually smaller than ½ of the inner diameter R of the annular electrode. When the inner diameter R of the annular electrode is 47.8 mm using a pipe of 47.8 mm), the width L of the annular electrode is usually about 20 mm or less. In this case, the fluid food with particularly high viscosity is used. In the material, the heating temperature unevenness was easily generated in the radial direction as described above. However, by setting the width L of each annular electrode to be larger than R / 2, it becomes possible to reduce the uneven heating temperature in the radial direction as compared with the conventional case.

  The effect of suppressing the heating temperature unevenness due to the dimension of the width L of the annular electrode as described above has been found by experiments of the present inventors. That is, the present inventors use a continuous-current heating apparatus as shown in FIG. 1 and FIG. 2 using a product made of Ti as the annular electrodes 7A, 7B, and 7C, and a high-viscosity fluid food having a viscosity of 100 cP or more. In conducting heating with a high frequency of 1 to 50 kHz, the interval between the annular electrodes 7A, 7B, 7C is constant, and the width L of the annular electrodes 7A, 7B, 7C is set to the inner diameter R of the annular electrodes 7A, 7B, 7C. On the other hand, when the state of occurrence of temperature unevenness in the radial direction in the pipe line 1 was examined by making various changes relatively, the width L was made relatively large with respect to the inner diameter R as schematically shown in FIG. As the L / R ratio increases (ie, the L / R ratio increases), the temperature non-uniformity is reduced. In particular, if the width L is 1/2 of the inner diameter R, ie, R / 2 or more, the temperature non-uniformity becomes practically satisfactory. L is equal to or greater than inner diameter R If the temperature unevenness was found more reliable and stable significantly smaller things. Therefore, in the present invention, the width L of the annular electrode is defined to be ½ or more of the inner diameter R. Even in the range of L ≧ R / 2, L ≧ R is particularly effective for reducing temperature unevenness.

  The reason why the temperature unevenness in the radial direction in the pipe line 1 can be suppressed by setting L ≧ R / 2, and further L ≧ R is not necessarily clear, but the width L of the annular electrode is increased. Along with this, it is considered that the current passing through the vicinity of the central axis position in the pipeline 1 increases (thus increasing the current density near the central axis position).

On the other hand, the upper limit of the width L of the annular electrode is not particularly defined, but if the width L exceeds three times the inner diameter R, the temperature unevenness suppressing effect is saturated, and if the width L is extremely large, the pipe of the heating unit , And consequently the size and cost of the apparatus may be increased. Therefore, the width L is usually not more than three times the inner diameter R of the annular electrode, that is,
L ≦ 3R
It is preferable that

  However, when a fluid food material having a viscosity of less than 100 cP is heated by current, even if the condition of L ≧ R / 2 is not satisfied, the heating temperature unevenness is small or hardly occurs, so the temperature unevenness suppressing effect is clearly Does not appear. Therefore, in the present invention, the flowable food material having a viscosity of 100 cP or more is limited to the case where it is heated by energization. In addition, among the food materials having a viscosity of 100 cP or more, the effect of suppressing the occurrence of temperature unevenness is particularly noticeable with respect to commodity materials having a viscosity of 1000 cP or more. It is preferable to apply to. Here, representative ones having a viscosity of less than 100 cP include soy sauce, Worcester sauce, orange juice, Calpis (trade name), olive oil, and the like. On the other hand, typical ones having a viscosity of 100 cP to 1000 cP include tomato juice, liquid egg, medium-concentrated sauce, gum syrup and the like, and those having a viscosity of 1000 cP or more mayonnaise, honey, custard cream, tomato ketchup, knead There are hot pepper, syrup, miso, etc., and these are the objects of application of this invention.

  Examples of the present invention are shown below together with comparative examples. In each of the following embodiments, conditions and the like are merely for explaining the effects of the present invention until they are tired, and it goes without saying that the conditions described in each embodiment do not limit the scope of the present invention.

Example 1
A continuous current heating apparatus as shown in FIG. 4 was used, and a continuous current heating experiment was performed using a CMC solution whose viscosity at 20 ° C. was adjusted to 95000 cP as a substitute for the fluid food material. Here, the outline of the apparatus shown in FIG. 4 is as follows.

  That is, the apparatus of FIG. 4 basically has two current heating units 20 and 22 each using three annular electrodes 7A, 7B and 7C (the basic configuration in each unit is shown in FIGS. 1 and 2). (Similar to those shown) are connected in series. However, in FIG. 4, ground electrodes 24 </ b> A and 24 </ b> B are provided near both ends of the units 20 and 22. Here, the pipe 1 having a nominal diameter of 1S was used. In this case, the inner diameter of the pipe line 1 is 23 mm, and the inner diameter R of each annular electrode 7A, 7B, 7C is also equal to the inner diameter of the pipe line 1 and is 23 mm. In addition, the width L in the pipe length direction of the annular electrodes 7A, 7B, and 7C was changed in five stages of 50 mm, 30 mm, 20 mm, 10 mm, and 6 mm, and each width was tested. The distance between each annular electrode 7A, 7B, 7C is 100 mm.

As an experimental condition, the CMC solution is introduced into the apparatus from the inflow path 26 at a flow rate of 120 l / hr or 80 l / hr, and a high frequency voltage of 20 kHz of 300 V or 400 V is applied between the annular electrodes 7A, 7B, 7C. The CMC solution after heating was flowed out of the system through the outflow path 28. At this time, the average temperature of the CMC solution in the inlet channel 26, i.e. with measuring the average inflow-side temperature T ₁ of the previous energization heating, the average temperature of the CMC solution in the outlet channel 28, i.e. the average outflow-side temperature after current heating T ₂ The average temperature rise Δt ₁ = T ₂ −T ₁ was determined. Also at the outlet side of the most downstream of the annular electrode 27C of the electrical heating unit 22 on the downstream side, to measure the temperature T ₄ of the central axis position of the temperature T ₃ and the conduit 1 of the tube wall in line 1, the temperature The difference (that is, temperature unevenness between the tube wall and the center) Δt ₂ was determined as Δt ₂ = T ₃ −T ₄ . Further, the value representing the degree of temperature unevenness is a value obtained by normalizing the temperature difference Δt ₂ between the tube wall and the center by the average temperature increase Δt ₁ due to heating, that is, a value of Δt ₂ / Δt ₁ . And the value of Δt ₂ / Δt ₁ was defined as the temperature unevenness ratio.

  The above results are shown in Tables 1 and 2.

Here, the relationship between each temperature unevenness ratio Δt ₂ / Δt ₁ in Tables 1 and 2 and the width L of the annular electrode is shown in a graph in FIGS. That is, FIG. 5 shows an example (experiment number 1 to 5) in the case of a flow rate of 120 l / hr and a voltage of 300 V in Table 1 and an example (experiment number of 6 to 10) in the case of a flow rate of 120 l / hr and a voltage of 400 V. 6 shows an example in the case of a flow rate of 80 l / hr and a voltage of 300 V in Table 2 (experiment numbers 11 to 15) and an example of a flow rate of 80 l / hr and a voltage of 400 V (experiment numbers 16 to 20).

As is apparent from FIGS. 5 and 6, in any case, the temperature unevenness ratio Δt ₂ / Δt ₁ tends to decrease as the width L of the annular electrode increases, and in particular, the present invention in which the width L is R / 2 or more. In the examples (Experiment Nos. 1-3, 6-8, 11-13, 16-18), from the comparative examples (Experiment Nos. 4, 5, 9, 10, 14, 15, 19, 20) which were experimented under the same conditions, respectively. It is clear that the temperature unevenness ratio Δt ₂ / Δt ₁ is reliably reduced.

Example 2
Using a pipe 1 having a nominal diameter of 2S (inner diameter of 47.8 mm), the inner diameter R of the annular electrode is set to 47.8 mm, and the width L of the annular electrode is changed in four stages of 100 mm, 60 mm, 50 mm, and 20 mm, The experiment was performed in the same manner as in Example 1 except that the distance between the annular electrodes was 200 mm. The flow rate was fixed at 365 l / hr, and energization heating was performed with two voltages of 480 V and 360 V.

The results are shown in Table 3 according to Tables ₁ and _2, and the relationship between the temperature unevenness ratio Δt ₂ / Δt ₁ and the width L of the annular electrode is shown in a graph in FIG.

As is apparent from FIG. 7, in the case of Example 2, the temperature unevenness ratio Δt ₂ / Δt ₁ tends to decrease as the width L of the annular electrode increases. When the ratio was 2 or more, the temperature unevenness ratio Δt ₂ / Δt ₁ could be reliably reduced.

It is a longitudinal cross-sectional view which shows an example of the continuous electricity heating apparatus of this invention. It is a cross-sectional plan view in the II-II line | wire of FIG. It is a graph which shows typically the relation between the ratio L / R of the width L of the annular electrode in the pipe length direction and the inner diameter R in the continuous energization heating device, and the radial temperature unevenness in the pipe. It is a schematic diagram which shows the whole structure of the continuous electricity heating apparatus used in the Example of this invention. Is a graph showing the relationship between the width L of the temperature variation ratio Delta] t ₂ / Delta] t ₁ and the annular electrode in Experiment No. 1-5 and Experiment No. 6-10 of Example 1. Is a graph showing the relationship between the width L of the temperature variation ratio Delta] t ₂ / Delta] t ₁ and the annular electrode in Experiment No. 11 to 15 and Test No. 16 to 20 of Example 1. Is a graph showing the relationship between the width L of the temperature variation ratio Delta] t ₂ / Delta] t ₁ and the annular electrode in Experiment No. 21 to 24 and Test No. 25 to 28 of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe line 2 Flow path 3 Flowable food material 7A, 7B, 7C Annular electrode 9 Power supply L Width of annular electrode in length direction R Inner diameter of annular electrode

Claims (4)

An annular electrode is provided in at least two or more portions at a predetermined interval from the upstream side to the downstream side of the pipeline so as to be concentric with the central axis of the pipeline, and the viscosity is 100 cP or higher. A high-viscosity fluid food product is obtained by passing a high-frequency current having a frequency in the range of 1 to 50 kHz between adjacent annular electrodes while continuously fluidly transporting the fluid food material in the length direction in the pipe. In a continuous current heating device for high viscosity fluid food materials for continuous current heating of materials,
The continuous energization heating device for high-viscosity fluid food material, characterized in that the dimension of the width L in the pipe length direction of each annular electrode is set to R / 2 or more with respect to the inner diameter dimension R of the annular electrode. . In the continuous energization heating apparatus of the high-viscosity fluid food material according to claim 1,
The continuous energization heating device for high-viscosity fluid food material, wherein the dimension of the width L in the pipe length direction of each annular electrode is set to be equal to or larger than the inner diameter dimension R of the annular electrode. In the continuous energization heating apparatus of the high-viscosity fluid food material according to claim 1 or 2,
The continuous energization heating apparatus for high-viscosity fluid food materials, wherein the dimension of the width L in the pipe length direction of each annular electrode is set to a dimension not more than three times the inner diameter dimension R of the annular electrode. In the continuous electricity heating apparatus of the high-viscosity fluid food material according to any one of claims 1 to 3,
A continuous energization heating device for high-viscosity fluid food materials, which is for electrically heating fluid materials having a viscosity of 1000 cP or more.

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