JPS5915029Y2 - High frequency heating device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus that uses high-frequency dielectric heating to thaw frozen foods, for example.

The high frequency heating device includes, for example, 2450 MHz UHF.
There are two types: one that uses VHF band microwaves and the other that uses VHF band microwaves such as 13 MHz, and each has its own characteristics in terms of thawing speed, thawing uniformity, operability, economic efficiency, etc. An appropriate method is selected depending on the type of object to be thawed, but the structural difference between the two is that the former emits radio waves from an antenna installed in a sealed metal cavity, like in a microwave oven, while the latter Generally, a uniform high-frequency electric field is formed between the electrodes by a high-frequency voltage applied to a pair of metal parallel plate electrodes (or grid electrodes), and the object to be thawed is inserted between the electrodes to perform defrosting etc. by dielectric heating effect. The present invention relates to the latter electrode-type high-frequency heating device.

When using a high-frequency heating device to thaw fresh frozen food such as frozen fish or frozen meat, the outer surface of the food, which is in contact with air at a higher temperature than the frozen food, rises in temperature faster than the inside and is thawed. The energy from the high-frequency waves is absorbed by the outer surface, which has become water, making it impossible to thaw the inside sufficiently, and the thawed outer surface is overheated by the concentrated energy and deteriorates in quality. This may cause the phenomenon.

Therefore, in order to prevent such local heating, a method is known in which frozen food is thawed while being blown with cold air.

On the other hand, since it is necessary to appropriately adjust the interval between the electrodes depending on the size, shape, etc. of the frozen food, a mechanism for raising and lowering the electrodes is generally provided.

In FIG. 1, reference numeral 1 denotes a thawing chamber in which an object 2 to be thawed such as frozen food is stored, 3 and 3' a pair of parallel plate electrodes, and 4 and 5 provided on opposite side walls of the thawing chamber 1. Ducts 6 and 7 communicate with the room, and ducts 4 and 5 are air inlets and exhaust ports for cold air provided in the partition wall of the thawing chamber 1,
Each has a cold air rectification mechanism.

8 is a cold air blower; 9 is a cooling air blower that lifts and lowers the electrode 3;
10.11 is a ceiling plate and a bottom plate of the defrosting chamber, which have a heat insulating structure together with the cold air ducts 4 and 5.

Further, 12 is a high frequency generator which supplies high frequency power to the electrodes 3 and 3' through lead wires 13 and 13'.

In FIG. 1, when the height H of the object 2 to be thawed is low, the upper electrode 3 is lowered by the adjusting mechanism 9 and thawing is started after adjusting the distance to an appropriate distance.

In this case, the cold air sent out from the cold air duct 4 does not effectively act on the object to be thawed, and a portion of it passes directly over the electrode and heads toward the exhaust lower.

In order to avoid this, adjusting the shape and size of the air supply port 6 and the exhaust lower each time according to the rise and fall of the electrode is complicated and extremely difficult in practice.

This proposal was made to solve these shortcomings,
To explain with reference to FIG. 2, 1 to 13 indicate the same parts as in FIG. Constructed with less insulation material.

The cold air guide plate 14 is bent upward at a portion facing the cold air inlet 6 and the exhaust lower, and directs air flowing in and out from the air inlet 6 and the portion of the exhaust lower located above the electrode 3. In order to effectively spray the material 2 to be thawed, the bent portion has a smooth curved shape.

Further, the height of the bent portion is selected to be an appropriate value depending on the range in which the electrode can be raised and lowered.

Since it is configured as described above, the cold air guide plate 14
Since the upper electrode 3 moves up and down together with the upper electrode 3, when the electrode 3 is raised and lowered according to the height H of the object 2 to be thawed, cold air can always be effectively blown onto the object 2 to be thawed.

In addition, when adjusting the electrode spacing according to the shape of the thawed object 2, if the distance between the upper electrode 3 and the thawed object 2 is too close, a discharge phenomenon may occur, or if the adjustment is incorrect, the thawed object 2 and the electrode If the plates 3 come into contact, a short circuit phenomenon will occur and the high frequency generator will be overloaded. However, when the insulating cold air guide plate 14 is provided on the lower surface of the electrode as described above, there is a risk of the above-mentioned discharge or short circuit phenomenon occurring. has no advantage.

Although this example describes a high-frequency decompression device,
It goes without saying that similar effects can also be applied to ventilation mechanisms for drying and the like using general high-frequency dielectric heating.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a conventional example, and FIG. 2 is a vertical sectional view showing an embodiment of this invention. In the figure, 1 is a heating chamber, 2 is an object to be heated, 3 and 3' are electrode devices, 6 is an air supply port, 7 is an exhaust port, 8 is a blower device, 9 is an adjustment mechanism, and 14 is a wind guide plate. be.

Claims (1)

[Scope of utility model registration request] a heating chamber 1 that accommodates the object to be heated 2 and has an air supply port 6 and an exhaust lower; an electrode device 3.3' that is placed oppositely in the heating chamber 1 and between which the object to be heated 2 is interposed; An adjustment mechanism 9 that adjusts the spacing between the electrode devices 3 and 3' in accordance with the size of the object to be heated 2, and an air blower that communicates with the air outlet 6 and the exhaust lower and blows air into the heating chamber 1. Equipped with 8,
The feature is that a wind guide plate 14 is provided to guide the air flowing in from the air supply port 6 to the electrode device 3° 3' in accordance with the adjustment of the facing distance between the electrode devices 3 and 3' by the adjustment mechanism 9. High frequency heating equipment.