JP2000225175A - Sterilizer for liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate variance of sterilization effect by compensating variance to eliminate variance in sterilizing treatment temperature even when the variance is produced in preheating temperature of liquid by a preheater. SOLUTION: This sterilizer is equipped with a controller 20a and an entrance temperature meter 26 which measures temperature T1 of just before sterilizing treatment of liquid supplied to the sterilization part 10 from the preheater 8 and gives the temperature the controller 20a. Using the temperature T1 of just before sterilizing treatment measured by the entrance temperature meter 26 and a target temperature T2 of the temperature reaching after sterilization of the liquid 2 at the sterilization part 10, the controller 20a calculates the optimum repeating frequency f0, which is a repeating frequency (f) of the pulse voltage Vp supplied to the sterilization part 10 from the pulse power source 19, of the liquid 2 at the sterilization part 10 and controls the repeating frequency (f) of the pulse voltage Vp supplied to the sterilization part 10 from the pulse power source 18 so as to be the optimum repeating frequency f0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse of a high electric field on liquids (including liquids) such as beverages (juice, milk, etc.), liquid eggs, water, lotion, liquid medicines, hydroponic liquids, culture liquids and the like. The present invention relates to a sterilization apparatus for performing a sterilization treatment by applying an electric field, and more specifically, to a means for preventing a variation in a temperature reached after a sterilization treatment of a liquid material to prevent a variation in a sterilization effect.

[0002]

2. Description of the Related Art As a method for sterilizing a liquid material, a heat sterilization method of heating a liquid material is widely known. In the heat sterilization method, a liquid material is heated to, for example, about 70 ° C. to 140 ° C. Due to heating, the flavor and nutritional value of liquids such as foods are reduced, a lot of energy is required for sterilization,
And other issues.

[0003] As a sterilization method replacing the heat sterilization method, an electric field sterilization method using a pulsed electric field has attracted attention, and a technique relating to this is described in, for example, Japanese Patent Publication No. 3-11755. In brief, the electric field sterilization method is a method of applying a pulsed electric field (specifically, a pulsed high electric field) to a liquid material a certain number of times, thereby destroying and sterilizing bacterial cell membranes in the liquid material. According to this method, sterilization can be performed without heating the liquid material as in the conventional heat sterilization method. Therefore, this electric field sterilization method has the features that it can be pasteurized, does not reduce the flavor and nutritional value of the liquid material, and can save energy because it does not require much energy for sterilization. .

However, also in the electric field sterilization method, if the liquid material is preliminarily heated to a lower temperature (for example, about 40 ° C.) than the conventional heat sterilization method, and then the pulse electric field application sterilization treatment is performed, It is known that the bactericidal effect is further enhanced. FIG. 3 shows a conventional example of a sterilizer according to this method.

[0005] This sterilizer comprises an untreated tank 4 for storing the liquid 2 before sterilization, a pump 6 for sending out the liquid 2 from the untreated tank 4, and a liquid 2 to be supplied to the sterilization section 10.
The a preheater 8 to preliminarily heated, the sterilizing unit 10 for sterilizing the liquid substance 2 by the pulse electric field E _P, a pulse power source 18 for applying repeatedly a pulse voltage V _P to the sterilization unit 10, The apparatus includes a control device 20 for controlling the pulse power supply 18 and a treated tank 22 for storing the sterilized liquid 2 discharged from the sterilization processing unit 10.

In this example, the sterilizing section 10 has two electrodes 12 and 14 arranged alongside each other, and the liquid 2 flows between the electrodes 12 and 14. The pulse voltage V _{P is} applied between the electrodes 12 and 14 from the pulse power supply 18.
Are supplied repeatedly, so that the two electrodes 12, 14
Pulsed electric field E _P in the liquid product 2 between is applied repeatedly,
Thereby, the liquid material 2 is sterilized. In this example, the two electrodes 12 and 14 have a parallel plate shape as an example, but may have a coaxial cylindrical shape or the like. Reference numeral 16 denotes an insulator.

[0007] Incidentally, the pulse number N of the pulse electric field E _P applied to the liquid product 2 in the sterilization unit 10, the flow rate of the liquid product 2 through the sterilizing section 10 Q [cc / s], the two electrodes 12 , 14, the volume of the electric field processing space is M [cc],
If the repetition frequency of the pulsed electric field E _P was f [Hz], it is expressed by the following equation. Note that M / Q in this equation is
The time [s] that the liquid material 2 passes through the sterilizing section 10 is shown.

[0008]

N = M · f / Q

[0010] By preliminarily heating the liquid material 2 before the electric field sterilization treatment by using the preheater 8 or the like, the sterilization effect (bacterial activity) is at least about 100 times that in the case where the heating is not performed. It is known that the germicidal rate is improved.

The degree of preliminary heating of the liquid material 2 varies depending on the kind of bacteria in the liquid material 2 and the like, but the ultimate temperature of the liquid material 2 is preferably about 35 ° C. to 60 ° C., more preferably 40 ° C. to 50 ° C.
The degree is more preferred.

The higher the preliminary heating temperature of the liquid material 2, the higher the sterilizing effect. However, the higher the heating temperature, the higher the effect of the electric field sterilization method compared to the conventional heat sterilization method (that is, pasteurization is possible, energy saving is possible). Is small), so that the preliminary heating is preferably minimized.

Further, since the temperature of the liquid substance 2 is raised by Joule heating by application of the pulse electric field E _P in the sterilization unit 10, for preventing decrease such as flavor of the liquid substance 2, the liquid material 2 including the temperature rise due to the temperature rise and the pulse electric field E _P applied by preheating, sterilizing unit 10
It is preferable that the temperature reached after the sterilization treatment of the liquid material 2 in the above is also made as low as possible.

[0013]

In the above-mentioned conventional sterilizing apparatus, when the preliminary heating temperature of the liquid material 2 by the pre-heater 8 varies, the sterilizing process of the liquid material 2 in the sterilizing section 10 is performed as described above. The post-attainment temperature also varies. It has been found that there is a close relationship between the pulsed electric field sterilization effect and the temperature of the liquid material. Therefore, the fluctuation of the preliminary heating temperature of the liquid material 2 causes a large fluctuation in the sterilization effect in the sterilization processing unit 10. For example, when the temperature reached after the sterilization process in the sterilization processing unit 10 fluctuates by about 5 ° C., the sterilization effect on the liquid material 2 may vary by a factor of 10 or more depending on the bacterial species.

As a solution to this, the preliminary heating by the pre-heater 8 is sufficiently (sufficiently) sufficient that a slight variation in the temperature reached after sterilization of the liquid material 2 in the sterilization processing section 10 can be ignored. However, in this method, the liquid material 2 after the sterilization treatment is used.
Of the electric field sterilization method, which is capable of pasteurization and energy saving, is reduced. In particular, as for the temperature reached after the sterilization of the liquid material 2 in the sterilization processing section 10, there is a strong demand to lower the temperature, so that the above method cannot be easily adopted.

There is also an idea that the outlet temperature of the pre-heater 8 is measured and feedback control is performed on the pre-heater 8 to improve the accuracy of preliminary heating of the liquid material 2 by the pre-heater 8. In this method, it is difficult to perform high-precision temperature control because the time response of the temperature control in the pre-heater 8 is poor. This is because the pre-heater 8 is generally
The heater 2 is used to indirectly heat the liquid material 2 (ie, via a heat exchanger or the like), and measures the temperature of the outlet of the pre-heater 8 → increases / decreases the heater current → increases / decreases the heater temperature → increases / decreases the liquid material temperature This is because a response delay inevitably occurs in control. In addition, due to such a cause, especially in a transitional temperature condition such as when starting up the sterilizing apparatus, the preheating temperature is not constant, and the sterilizing effect varies greatly.

Accordingly, the present invention compensates for any variation in the preliminary heating temperature of the liquid material by the pre-heater quickly, and reduces the variation in the temperature reached after the sterilization of the liquid material in the sterilization section. A main object of the present invention is to provide a sterilization apparatus that can eliminate the sterilization effect and prevent the dispersion of the sterilization effect.

[0017]

According to one aspect of the present invention, there is provided a sterilization apparatus comprising: an inlet temperature measuring device for measuring a temperature immediately before a sterilizing process of a liquid material supplied to the sterilizing section; Using the measured temperature immediately before the sterilization treatment and the target value of the temperature reached after the sterilization treatment of the liquid material in the sterilization treatment section, the repetition frequency of the pulse voltage supplied from the pulse power supply to the sterilization treatment section, Calculate the optimum repetition frequency at which the temperature reached after the sterilization treatment of the liquid material in the processing unit is the target value, and calculate the repetition frequency of the pulse voltage supplied from the pulse power supply to the sterilization processing unit so as to be the optimum repetition frequency. And a control device for controlling (claim 1).

By controlling the repetition frequency of the pulse voltage supplied to the sterilizing section, it is possible to accurately and promptly control the temperature rise of the liquid material due to the sterilizing process by applying the pulse electric field in the sterilizing section.

Therefore, the controller supplies the sterilization processing section from the pulse power source using the temperature immediately before the sterilization processing measured by the inlet temperature measuring device and the target value of the attained temperature after the sterilization processing of the liquid material in the sterilization processing section. The repetition frequency of the pulse voltage to be applied, and the optimum repetition frequency at which the temperature reached after the sterilization of the liquid material in the sterilization processing unit reaches the target value is calculated. By controlling the repetition frequency of the pulse voltage to be supplied to the liquid material, even if the preliminary heating temperature of the liquid material by the pre-heater fluctuates, this is quickly compensated for and the sterilization processing of the liquid material in the sterilization processing section Variations in the post-reaching temperature can be eliminated, and variations in the sterilization effect can be prevented.

Instead of controlling the repetition frequency of the pulse voltage, a voltage value of the pulse voltage may be controlled.

Further, instead of the inlet temperature measuring device, an outlet temperature measuring device for measuring the temperature reached after the sterilization of the liquid material immediately after leaving the sterilizing section is provided, and the temperature measured by the outlet and the target temperature are measured. The control may be performed so that the difference becomes 0 (claims 3 and 4).

[0022]

FIG. 1 is a schematic view showing an example of a sterilizer according to the present invention. Parts that are the same as or correspond to those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and differences from the conventional example will be mainly described below.

The sterilizing apparatus includes a control unit 20a as described below in addition to the untreated tank 4, the pump 6, the preheater 8, the sterilizing unit 10, the pulse power supply 18, and the treated tank 22 as described above. An inlet temperature measuring device 26 is provided.

The inlet temperature measuring device 26 is provided near the inlet of the sterilizing section 10 and measures the temperature T ₁ immediately before the sterilizing process of the liquid 2 supplied to the sterilizing section 10 from the preheater 8. gives the sterilizing treatment just before temperatures T ₁ which is the measurement to the controller 20a.

The control device 20a uses the temperature T ₁ immediately before the sterilization process measured by the inlet temperature measuring device 26 and the target value T _{2 of the} attained temperature after the sterilization process of the liquid material 2 in the sterilization processing section 10 for the pulse power supply 18. a repetition frequency f of the pulse voltage V _P supplied to the sterilization unit 10, sterilizing unit 10
Attained after the sterilization treatment of the liquid material 2 at the target value T
The optimum repetition frequency f ₀ becomes ₂ calculated, so as to the optimum repetition frequency f _0, and controls the repetition frequency f of the pulse voltage V _P supplied from the pulse power source 18 to the sterilization unit 10.

[0026] Accordingly, the pulse power source 18 in this example, then at least the repetition frequency f of the pulse voltage V _P to be output is of a variable (variable by control of the control unit 20a).

More specifically, in the sterilization processing section 10, 1
The application of shot pulse electric field E _P, the liquid substance 2, per unit volume, energy G represented by the following formula
Is input. Here, the electric field strength E is pulsed electric field E _P [V / cm], the pulse width of τ is the pulse electric field E _P [s],
ρ is the specific resistance [Ωcm] of the liquid material 2.

[0028]

G = E ² τ / ρ [J]

As a result, the temperature rise ΔT per one shot of the pulsed electric field of the liquid material 2 is expressed by the following equation.

[0030]

ΔT = G / 4.2 = E ² τ / 4.2ρ [° C.]

For example, when the electric field strength E is 50 kV / cm, the pulse width τ is 1 μs, and the specific resistance ρ is 300 Ωcm,
The liquid substance in the sterilizing treatment unit 10 2 is raised about 2 ℃ per shot pulse electric field E _P.

Here, a specific example of the control by the control device 20a will be briefly described.
Liquid material 2 supplied from preheater 8 to sterilization section 10
The temperature T ₁ immediately before the sterilization treatment is 40 ° C.
0 temperature reached after sterilization of the liquid product 2 after pulsed electric field E _P application of 10 pulses at the 60 ° C. (i.e. the [Delta] T = 2
° C) for some reason (eg preheater 8
), The temperature T ₁ immediately before the sterilization treatment reaches 36 ° C.
In (which is a total number of applied pulses) pulse number N of the pulse electric field E _P applied to the liquid material 2 if the 12 pulse, of 60 ° C. The sterilized after reaching the temperature of the liquid substance 2 in the sterilization unit 10 It can be maintained at a constant value,
Can compensate for variations in the preliminary heating temperature. Such control is performed by the control device 20a.

That is, the controller 20a has an inlet temperature measurement.
From the vessel 26, the temperature T immediately before the sterilization treatment ₁Is given. Change
In this example, the control device 20a includes a
Target value T of the temperature reached after the sterilization treatment of the liquid material 2_Two,Up
The temperature rise ΔT per one shot shown in the notation 3 and
The electric field processing space of the sterilization processing unit 10 described in the above equation (1)
Is set. Further, in this example, the sterilizing section 1
Flow meter for measuring the above flow rate Q of the liquid material 2 supplied to 0
24 is provided on the inlet side of the sterilizing section 10 and the flow rate
Q is provided to control device 20a. However, usually sterilization
Since the flow rate Q is not changed during processing (that is, the flow rate Q is
Control of the flow rate Q without providing the flow meter 24
It may be set in the device 20a.

Assuming that the temperature immediately before the sterilization process is T ₁ and the target value of the attained temperature after the sterilization process is T ₂ , the optimum number of pulses N ₀ applied to the liquid material 2 in the sterilization processing unit 10 is expressed by the following equation. The term “optimal” means a temperature at which the difference between the temperature reached after sterilization of the liquid material 2 in the sterilization processing unit 10 and its target value can be eliminated.

[0035]

N ₀ = (T ₂ −T ₁ ) / ΔT

## EQU4 ## From Equation (4) and Equations (1) and (3) above,
The optimum repetition frequency f _{0 at} which the temperature reached after the sterilization of the liquid material 2 in the sterilization processing section 10 becomes the target value T ₂ can be obtained. It is shown in the following equation.

[0037]

F ₀ = (T ₂ −T ₁ ) Q / ΔTM [Hz]

The control device 20a performs an operation such as the following equation (5), and determines the optimum repetition frequency f ₀ obtained by this operation.
So that, to control the repetition frequency f of the pulse voltage V _P to be supplied to the sterilization unit 10 from the pulse power source 18.

The pulse voltage V _P supplied to the sterilizing section 10
By controlling the repetition frequency f, the temperature rise of the liquid material 2 due to the pulsed electric field sterilization in the sterilization processing unit 10 can be accurately and promptly controlled.

[0040] That is, the temperature rise of the liquid product 2 due to the application of the pulsed electric field E _P, unlike the case of the preheater 8 to indirectly heat the liquid material 2 by using a heater or the like, the energy in the liquid substance 2 Since it is directly input, it can be accurately grasped from the above equation (3). Therefore, control of the pulse electric field E _P, more specifically can be the control of the repetition frequency f, to precisely control the temperature rise of the liquid product 2.

[0041] Moreover, it is possible to the energy in the liquid substance 2 by the application of pulsed electric field E _P directly introduced to control the temperature of the liquid product 2, use the preheater 8 and a feedback control system having a heater The temperature control of the liquid material 2 can be performed promptly (that is, with a good time response) as compared with the case where the liquid material 2 is provided. Therefore, temperature control can be performed quickly even under transient temperature conditions such as when the sterilizer is started.

The control by the control device 20a is as follows.
In other words, it is a kind of feed-forward control because the temperature reached after the sterilization of the liquid material 2 in the sterilization processing unit 10 is predicted and controlled in advance, and the actual sterilization processing of the liquid material 2 in the sterilization processing unit 10 is performed. It can be said that the time responsiveness is higher than that of feedback control in which the post-attainment temperature is measured and corrected.

Accordingly, by controlling the repetition frequency f as described above by the control device 20a, even if the preliminary heating temperature of the liquid material 2 by the preliminary heater 8 fluctuates, it is quickly compensated. And sterilization processing unit 10
In this case, it is possible to eliminate the variation in the temperature reached after the sterilization treatment of the liquid material 2 and keep the temperature constant. As a result, it is possible to prevent variations in the germicidal effect on the liquid material 2.

Further, in the conventional feedback control system described with reference to FIG. 3, in order to improve the time response and the accuracy of the preheating, the entire system has to be of a very high-grade high response. Although the cost of the pre-heating system including the pre-heating device 8 and its feedback control system is extremely high, the sterilizing apparatus of the present invention originally has a time response as originally described. As a result, the cost of the apparatus can be reduced as compared with the method of increasing the accuracy of the preheating.

In the above example, the repetition frequency f of the pulse voltage V _P supplied to the sterilizing section 10, that is, the repetition frequency f of the pulse electric field E _P applied to the liquid material 2 in the sterilizing section 10 is controlled. In order to compensate for the variation in the preheating temperature of the object 2, instead of controlling the repetition frequency f (that is, keeping the repetition frequency f constant), the pulse electric field E applied to the liquid material 2 in the sterilization processing unit 10 The electric field intensity E of _P may be controlled. Electric field strength E
As can be seen from the above equation (3), similarly to the case of the control of the repetition frequency f, the temperature rise of the liquid material 2 in the sterilizing section 10 can be controlled accurately and with good responsiveness. is there. Therefore, the same effect as in the above example in which the repetition frequency f is controlled is obtained. Control of the electric field strength E is specifically performed by controlling the voltage value V of the pulse voltage V _P to be supplied to the sterilization unit 10.

That is, from the above equations (3) and (4), the optimum electric field intensity E ₀ at which the temperature after the sterilization of the liquid material 2 in the sterilization processing section 10 reaches the target value T ₂ is expressed by the following equation.

[0047]

E ₀ = √ ｛(T ₂ −T ₁ ) Q4.2ρ / Mf
τ｝ [V / cm]

On the other hand, both electrodes 12, 14 of the sterilizing section 10
When the distance between the d [cm], the voltage value of the pulse voltage V _P applied to the sterilizing unit 10 (in other words, the voltage magnitude, or amplitude) and V, of the pulse electric field E _P in the sterilization unit 10 The following relationship is established with the electric field strength E.

[0049]

E = V / d [V / cm]

Accordingly, from the equations (7) and (6), the optimum voltage value V ₀ at which the temperature after the sterilization of the liquid material 2 in the sterilization section 10 reaches the target value T ₂ is expressed by the following equation.

[0051]

V ₀ = E ₀ d = √ ｛(T ₂ −T ₁ ) Q4.2ρ
/ Mfτ｝ × d [V]

Therefore, the control device 20a performs an operation, for example, as shown in the following equation (8), and controls the sterilization processing unit 10 from the pulse power supply 18 so that the optimum voltage value V ₀ obtained by the operation is obtained.
It may be to control the voltage value V of the pulse voltage V _P to be supplied to. In this case, instead of the temperature increase ΔT, the control device 20a provides the specific resistance ρ that constitutes Expression 8 above,
What is necessary is just to set the repetition frequency f, the pulse width τ, and the distance d. The pulse power supply 18, then at least the voltage value V variable (controller of the pulse voltage V _P to output 20
(variable under control from a).

[0053] Incidentally, although there is also considered that controls the pulse width τ of the pulse voltage V _P applied to the sterilization unit 10, the pulse width τ usually be fixed to a single value by a circuit constant of the pulse power source 18 It is not preferable to adopt this idea because it is difficult to arbitrarily control.

FIG. 2 is a schematic view showing another example of the sterilizer according to the present invention. The following mainly describes the differences from the example of FIG.

In brief, the sterilization apparatus of this example detects a difference between the temperature T ₃ after the sterilization of the liquid material 2 immediately after it has exited from the sterilization processing section 10 and the target temperature (target value) T _2. and, if the post-sterilization temperature reached T ₃ lower than the target temperature T ₂ increases the pulse voltage V _P of the repetition frequency f (or the voltage value V) accordingly, if the reverse pulse voltage V _P repetition frequency f (Or the voltage value V). Such control is performed by the control device 20b.

For this purpose, in this example, instead of the inlet temperature measuring device 26 (see FIG. 1), the liquid material 2 immediately after exiting from the sterilizing section 10 is sterilized near the outlet of the sterilizing section 10. An outlet temperature measuring device 28 for measuring the attained temperature T ₃ is provided, and the after-sterilization attained temperature T ₃ measured by this is given to the control device 20b.

[0057] To a difference between the target value T ₂ of the post-sterilization temperature reached and the measured value T ₃ to 0, the pulse number N of the pulse voltage V _P applied to the sterilization unit 10 from the pulse power source 18 following What is necessary is just to increase or decrease by the formula. ΔT is the above-mentioned temperature rise per shot.

[0058]

## EQU9 ## ΔN = (T ₂ −T ₃ ) / ΔT

The pulse voltage V _P applied to the sterilization unit 10 from the pulse power source 18 is calculated using the above equation (1).
To the repetition frequency f, the increase / decrease Δ of the repetition frequency f
f is represented by the following equation.

[0060]

Δf = (T ₂ −T ₃ ) Q / ΔTM [Hz]

Control (feedback control) for increasing or decreasing the repetition frequency f according to the equation (10) is performed by the control device 20b in this example. Therefore, the pulse power supply 18 of this example
Is then at least the repetition frequency f of the pulse voltage V _P to be output is of a variable (variable by control of the control unit 20b).

As a result, even if the preliminary heating temperature of the liquid 2 by the pre-heater 8 fluctuates, this is compensated for, and the fluctuation of the temperature reached after the sterilization of the liquid 2 in the sterilization section 10 is compensated for. It can be kept constant without it. As a result, it is possible to prevent variations in the germicidal effect on the liquid material 2.

[0063] Moreover, in the case of this example, as in the example of FIG. 1, and controls the temperature rise of the liquid product 2 under the control of the pulsed electric field E _P applied to the liquid substance 2 in the sterilization unit 10, the liquid The temperature of the object 2 can be controlled accurately and promptly (that is, with good time response).

Also in the case of the example of FIG. 2, instead of increasing / decreasing the repetition frequency f (that is, keeping the repetition frequency f constant), as in the example of FIG. the voltage value V of the pulse voltage V _P may be increased or decreased to. In this case, the same effect as in the case where the repetition frequency f is controlled can be obtained.

In this case, the target value T of the temperature reached after the sterilization treatment
The difference between the ₂ and the measured value T ₃ to 0, the voltage value V of the pulse voltage V _P applied from the pulse power source 18 to the sterilization unit 10 may be increased or decreased according to the following equation.

[0066]

ΔV = √ ｛(T ₂ −T ₃ ) Q4.2ρ / Mf
τ｝ × d [V]

The control (feedback control) for increasing or decreasing the voltage value V according to the equation (11) is performed in this example.
b does. Parameters to be set in the control unit 20b in this case is similar to the case of controlling the voltage value V of the pulse voltage V _P in the example of FIG. The pulse power supply 18
At least the voltage value V of the pulse voltage V _P therefrom to output
Is variable (variable by control from the control device 20b).

The untreated liquid material 2 is added to the sterilizing section 10.
The means for supplying the liquid and recovering the processed liquid material 2 from the sterilization processing unit 10 is not limited to the above example.

Further, the liquid material 2 after the sterilization treatment in the sterilization treatment section 10 may be cooled for the purpose of long-term storage or the like.

Further, both cooling of the liquid material 2 after the sterilization process and preheating of the liquid material 2 before the sterilization process may be performed so that both the liquid materials 2 are heat-exchanged from the viewpoint of energy saving. .

As described above, the structure of the sterilizing section 10 is not limited to the parallel plate electrode, but may be another structure such as a coaxial electrode.

Further, the pulse power source 18 supplies the sterilizing section 10
The waveform of the pulse voltage V _P supplied to, is not limited to a specific one, for example, a rectangular waveform, exponential decay waveform,
A sine waveform, a composite waveform thereof, or the like may be used.

[0073]

As described above, according to the present invention, by controlling the repetition frequency or the voltage value of the pulse voltage applied to the sterilizing section, the energy applied to the liquid in the sterilizing section is directly controlled to control the liquid substance. Since the temperature rise can be controlled, the temperature of the liquid material can be accurately and promptly controlled. Therefore, even if there is a variation in the preliminary heating temperature of the liquid material by the pre-heater, it is to be compensated promptly to eliminate the variation in the temperature reached after the sterilization processing of the liquid material in the sterilization processing section and to keep it constant. Thus, it is possible to prevent the germicidal effect on the liquid material from fluctuating.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a sterilizer according to the present invention.

FIG. 2 is a schematic view showing another example of the sterilizing apparatus according to the present invention.

FIG. 3 is a schematic view showing an example of a conventional sterilization apparatus.

[Explanation of symbols]

2 liquid material 8 preheater 10 sterilization section 12, 14 electrodes 18 pulse power supply 20a, 20b control unit 26 inlet temperature instruments 28 outlet temperature instruments V _P pulse voltage E _P pulse field

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Kato 47-47 Umezu Takaune-cho, Ukyo-ku, Kyoto-shi, Kyoto (72) Inventor Kawakita Yes 47-47 Umezu-Takaune-cho, Ukyo-ku, Kyoto, Kyoto Nissin Electric In-house F term (reference) 4B021 LA42 LP01 LT03 LT06 LW06 4C058 AA21 AA22 AA30 BB02 BB10 CC01 CC02 DD02 DD04 DD12 DD20 EE12 EE26 4D061 DA03 DA10 DB01 EA02 EB01 EB07 EB14 EB18 EB19 GC01 EB39 GA01

Claims (4)

[Claims] 1. A sterilization section having two electrodes arranged alongside each other and through which a liquid material flows, and a pulse voltage is repeatedly supplied between the two electrodes of the sterilization section. A sterilizing apparatus for a liquid material, comprising: a pulse power supply for repeatedly applying a pulse electric field to the liquid material between the two electrodes; and a preheater for preliminarily heating the liquid material to be supplied to the sterilizing unit. An inlet temperature measuring device for measuring the temperature immediately before the sterilization treatment of the liquid material supplied to the part, and a target value of the temperature immediately before the sterilization treatment measured by the inlet temperature measuring device and the attained temperature after the sterilization treatment of the liquid material in the sterilization processing part. Using, the repetition frequency of the pulse voltage supplied from the pulse power supply to the sterilization processing unit, the optimal repetition frequency at which the temperature reached after the sterilization processing of the liquid material in the sterilization processing unit is the target value. Calculated, and the optimum so that the repetition frequency, the sterilizer of the liquid material, characterized in that it comprises a control device for controlling the repetition frequency of the pulse voltage supplied from the pulse power source to the sterilization section. 2. A sterilizing section having two electrodes arranged alongside each other, through which a liquid material flows between the two electrodes, and a pulse voltage is repeatedly supplied between the two electrodes of the sterilizing section. A sterilizing apparatus for a liquid material, comprising: a pulse power supply for repeatedly applying a pulse electric field to the liquid material between the two electrodes; and a preheater for preliminarily heating the liquid material to be supplied to the sterilizing unit. An inlet temperature measuring device for measuring the temperature immediately before the sterilization treatment of the liquid material supplied to the part, and a target value of the temperature immediately before the sterilization treatment measured by the inlet temperature measuring device and the attained temperature after the sterilization treatment of the liquid material in the sterilization processing part. With the use of the pulse power supply from the pulse power supply to the sterilization processing unit is a voltage value of the pulse voltage, the optimal voltage value at which the target temperature after the sterilization processing of the liquid material in the sterilization processing unit reaches the target value. ,this So that the proper voltage value, sterilizer liquid product, characterized in that it comprises a control device for controlling a voltage value of the pulse voltage supplied from the pulse power source to the sterilization section. 3. A sterilizing section having two electrodes arranged alongside each other, through which a liquid material flows, and a pulse voltage is repeatedly supplied between the two electrodes of the sterilizing section. A sterilizing apparatus for a liquid material, comprising: a pulse power supply for repeatedly applying a pulse electric field to the liquid material between the two electrodes; and a preheater for preliminarily heating the liquid material to be supplied to the sterilizing unit. Outlet temperature measuring device for measuring the temperature reached after the sterilization of the liquid material immediately after leaving the section, and the temperature reached after the sterilization treatment measured by the outlet temperature measuring device and the temperature reached after the sterilization of the liquid material in the sterilization processing section And a control device for increasing or decreasing the repetition frequency of a pulse voltage supplied from the pulse power supply to the sterilization processing unit so that the difference between the two temperatures becomes zero using the target value of the liquid material. Sterilization equipment . 4. A sterilizing section having two electrodes arranged alongside each other and through which a liquid material flows, and a pulse voltage is repeatedly supplied between the two electrodes of the sterilizing section. A sterilizing apparatus for a liquid material, comprising: a pulse power supply for repeatedly applying a pulse electric field to the liquid material between the two electrodes; and a preheater for preliminarily heating the liquid material to be supplied to the sterilizing unit. Outlet temperature measuring device for measuring the temperature reached after the sterilization of the liquid material immediately after leaving the section, and the temperature reached after the sterilization treatment measured by the outlet temperature measuring device and the temperature reached after the sterilization of the liquid material in the sterilization processing section And a control device for increasing or decreasing a voltage value of a pulse voltage supplied from the pulse power supply to the sterilization processing unit so that a difference between the two temperatures becomes zero using the target value of the liquid material. Sterilization equipment.