JPH0576327A - Apparatus for microwave heat treatment - Google Patents

Abstract

PURPOSE:To reduce heating load and cooling load due to a cooler by carrying out heat exchange between a liquid material supplied from a hopper through a feed pump for the purpose of treatment and a material heat treated by a microwave heater by using a heat exchanger. CONSTITUTION:A liquid material (A) to be treated is supplied by a feed pump 2 from a hopper 1 through a heat exchanger 3 to a microwave heater 4. Heat treated material (B) is sent through the heat exchanger to a water cooler 5 and sent out through a discharge passage 7. The flow path is switched to a circulation passage 8 by a flow-path control valve 6 so as to prevent discharge of insufficiently heated materials, e.g. at a time of start-up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave heat treatment apparatus for continuously heat treating a fluid such as liquid or viscous fluid by microwave irradiation.

[0002]

2. Description of the Related Art Conventionally, steam or superheated water has been used as a heat source for sterilizing or heat-processing liquid foods such as beverages, sauces and soups and viscous foods such as miso and kneaded products. There are many devices used. In this heat treatment apparatus, since it is indirect heating by heat transfer, it has drawbacks that the heating efficiency is low, it takes a long time to raise the temperature, and a large amount of energy consumption is required. Since the heat transfer surface is apt to burn, and additional equipment such as a boiler is required, there is a problem that the entire equipment becomes excessive.

Further, in recent years, devices using microwaves as a heating source have become widespread. In this heat treatment apparatus, since the object to be processed absorbs the microwave radiated to the object to be processed, the object is directly heated to be converted into heat energy and the temperature is raised. It is short, and it is heated uniformly and does not easily burn. Further, although it has an advantage that the structure of the device is simplified, there is a problem that the cost per unit amount of heat becomes high because electric power is used to generate the microwave.

[0004]

As a conventional microwave heat treatment apparatus, for example, in the apparatus disclosed in Japanese Patent Publication No. 63-19185, it is costly to heat an object to be treated to a predetermined temperature. Since it is performed only by high microwave irradiation, and heat recovery from the heat-treated product is not measured, there is a drawback that operating costs increase. In the present invention, by preheating the object to be processed by utilizing the amount of heat of the object to be processed after the heat treatment, heat recovery is measured, and the heating load due to microwave irradiation is reduced, resulting in a significant energy saving effect. It was made for the purpose of providing the obtained microwave heat treatment apparatus.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a microwave heat treatment apparatus for heat-treating an object having fluidity by microwave irradiation, the object being supplied from a hopper 1 by a supply pump 2. Heat exchanger 3 for exchanging heat between the heat treated material and the heat-treated material by the microwave heater 4, a cooler 5 for cooling the heat treated material from the heat exchanger 3 with cooling water, and a heat treated material from the cooler 5. The microwave heat treatment equipment is characterized in that a flow passage 7 for sending the water to the outside of the system or a circulation flow passage 8 for circulating to the hopper 1 and a flow passage control valve 6 for switching the flow passage are attached.

[0006]

The object A having fluidity is supplied to the hopper 1 from outside the system.
Is further supplied to the subsequent stage by the supply pump 2. The object A to be processed is heat-exchanged with the object B to be heat-treated in the heat exchanger 3 to be preheated and then supplied to the microwave heater 4, and is irradiated while being passed through the microwave permeable pipe. The generated microwaves are absorbed and converted into heat energy, and the temperature is raised to a predetermined processing temperature. Heat-treated processed product B
As described above, the heat is exchanged with the object to be processed A in the heat exchanger 3 to be cooled, further supplied to the cooler 5 and cooled to a predetermined temperature by the cooling water D, and then the flow path switching valve 6 is turned on. After that, the product C is delivered from the delivery channel 7 to the outside of the system.

Although the above is the case of normal operation, at the time of start-up or the like, microwaves are irradiated after the low temperature object A is filled in the system passage, and the object B is treated in a predetermined manner. It is discharged without being heated to the processing temperature.
Therefore, in such a case, the cooling of the processed material B in the cooler 5 is not performed, but the processed material B is circulated from the circulation flow path 8 to the hopper 1 through the flow path switching valve 6, so that the incompletely heated processed material is delivered. To be prevented.

[0008]

1 is a system diagram of an embodiment of the present invention, which will be described below with reference to the drawings. Reference numeral 1 is a hopper which receives and stores the fluidized object A from outside the system. Reference numeral 2 denotes a supply pump that continuously supplies a constant amount of the object A to be processed from the hopper 1 to the latter stage, and 3 is a heat exchanger for exchanging heat between the object A and the object B after the heat treatment. It is preferable to use a plate type heat exchanger or a double tube type heat exchanger for the object to be treated.

Reference numeral 4 denotes a microwave heater 4, which has an inlet for the object to be treated A and an outlet for the object to be treated B, and both ends of which are connected to the inlet and the outlet. Is mainly configured by an irradiation chamber in which is provided, a microwave oscillator that controls and transmits microwaves, and a waveguide that guides the microwaves from the microwave oscillator into the irradiation chamber.

Reference numeral 5 denotes a cooler for further cooling the processed material B cooled by the heat exchanger to a predetermined temperature with the cooling water D. A plate type heat exchanger or a scraping type heat exchanger is used. preferable. Reference numeral 6 designates a flow path of the processed material B passing through the cooler 5,
This is a flow path switching valve that switches between the circulation flow path 8 that circulates to the hopper 1 during the up operation and the delivery flow path 7 that sends the product C out of the system during normal operation.

The present invention is not limited to the above-mentioned structure, and if necessary, a holding portion may be provided on the outlet side of the processing object B of the microwave heater 4 to improve the processing effect by maintaining the temperature. Since the pressure rises in the high temperature treatment of 100 ° C. or higher, a pressure control device and the like are further installed as appropriate.

The operation of sterilizing an object having fluidity by the microwave heat treatment apparatus having the above-mentioned structure will be described below. The object A to be processed is continuously supplied to the hopper 1 from the outside of the system by a fixed amount. The object A to be processed is supplied into the pipeline of the microwave heater 4, and microwaves are emitted at the time of being fully filled, and heating by microwave irradiation is started.
Therefore, in the initial stage, the preheat in the heat exchanger 3 is not sufficiently performed, so that the object A to be processed does not reach the predetermined sterilization temperature and is sent from the microwave heater 4, so that the flow path switching valve At 6, the processing flow path B is switched to the circulation flow path 8 side to circulate the processed material B to the hopper 1. At this stage, cooling by the cooling water D in the cooler 5 is not performed.

When the heating in the microwave heater 4 progresses and the heat exchange in the heat exchanger 3 is sufficiently performed, the object A is preheated to a predetermined temperature, so that the heating in the microwave heater 4 is performed. By this, the sterilization temperature can be sufficiently reached. The heat-treated processed product B is cooled by exchanging heat with the processed product A in the heat exchanger 3, and then further cooled by the cooling water D in the cooler 5. The processed product B is sent out as the product C through the flow path switching valve 6 switched to the delivery flow path 7 side of the product C, and is supplied to a not-shown filling device in the subsequent stage. By such an action, the object to be treated is easily sterilized and can be delivered as a sterilized product.

[0014]

According to the present invention having the above-mentioned structure and operation, the following effects can be obtained. B) Since the object to be processed is preheated by the heat of the processed object after the heat treatment, heat recovery can be achieved, and a large energy saving effect can be obtained, and the heating load due to microwave irradiation can be reduced. B) The cooling load by the cooler is reduced and the amount of cooling water used is reduced. C) It is possible to prevent product loss and heat treatment incompleteness without sending out a processed product that has not reached a predetermined processing temperature to the outside of the system at the time of start-up.

[Brief description of drawings]

FIG. 1 is a system diagram of one embodiment.

[Explanation of symbols]

 1 hopper 2 supply pump 3 heat exchanger 4 microwave heater 5 cooler 6 flow path switching valve 7 delivery flow path 8 circulation flow path

Claims (1)

[Claims] 1. A microwave heat treatment apparatus for heat-treating an object having fluidity by microwave irradiation, the object being supplied from a hopper (1) by a supply pump (2) and a microwave heater ( A heat exchanger (3) for exchanging heat with the processed product heat-treated in 4), a cooler (5) for cooling the processed product from the heat exchanger (3) with cooling water, and a cooler (5). A flow passage (7) for sending the processed product from the outside to the system or a circulation flow passage (8) for circulating to the hopper (1) and a flow passage control valve (6) for switching the flow passage are attached. Microwave heat treatment device.