JPS607040Y2 - microwave heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave heating device, and more particularly to a microwave heating device that can continuously evaporate a solution of a dissolved liquid substance and raise the temperature of precipitated solid matter to a required temperature.

Conventionally, microwave heating devices have been conveniently used for cooking, industrial heating, raising the temperature of liquid and solid substances, drying moist substances, and the like.

However, when a solution of a dissolved liquid substance is evaporated into a solid substance and the solid substance is raised to a high temperature of several hundred degrees Celsius or more, the microwave absorption rate changes significantly due to the change in the amount of load accompanying the evaporation of the liquid. Moreover, even after it becomes a solid, the internal state of the solid changes as the temperature rises, and the microwave absorption efficiency changes, making it difficult to control the temperature rise and resulting in non-uniform finished products, which is not practical.

However, in recent years, there has been a demand to evaporate the solution of the dissolved liquid substance and raise the temperature of the precipitated solid substance to a required temperature while completely isolating the dissolved liquid substance from the outside world, due to concerns regarding public health and pollution. It's happening.

If you try to use conventional radiant heat or conductive heat to raise the temperature of such an object that is completely isolated from the outside world, the device will become large and the thermal effect will be very poor, making it difficult to raise the temperature of the contents. There were many problems that made it impractical, such as difficulty in achieving uniformity and difficulty in exchanging treated and untreated materials.

Therefore, microwave heating can be considered, but conventional microwave heating equipment heats over a wide area, which tends to cause uneven heating, and as mentioned above, the heat absorption efficiency changes as the steam evaporates and the temperature rises, making it difficult to maintain a uniform substance. However, there were disadvantages in that temperature control was difficult.

In order to eliminate these drawbacks, the present invention narrows the microwave power supply port, increases the density of the microwave power, and locally heats it, and also changes the state of the heated object by varying the microwave power density. This is a microwave heating device that adjusts the irradiation to a microwave power density that is suitable for the environment, and sequentially moves the object to be heated, from evaporating the solution to raising the temperature of the solid material. This will be explained in more detail below.

FIG. 1 shows an embodiment of the present invention, and a is a top view or an explanatory view as seen from the front.

1a to 1c are microwave waveguide power supply parts, 2 is a turntable, 3 is a groove-shaped container installed on the table, 4 is a choke-type microwave leakage prevention part, 5 is a motor for rotating the table, and 6 is a liquid inlet , 7 is a product outlet.

Furthermore, the chain double-dashed line portion indicates a cover or a cavity.

To operate this, the turntable 2 is rotated and a fixed amount of solution is supplied from the liquid input port 6.

The solution supplied to the table groove-shaped container 3 is transported by the rotation of the turntable 2, and is irradiated by the microwave waveguide feeding section 1 at 1 be 1 c, and heated and evaporated by the cavities each having a different microwave power density. However, the precipitated solids are further heat-treated according to the treatment conditions, and the treated solids are taken out from the product take-out lower.

For products in which the precipitated solids are fixed and sintered, a roll-type pulverizer or the like may be installed in front of the product take-out lower.

The easiest method for taking out is the overflow type using a scraper, but depending on the situation, screw conveyance, vibration conveyance, etc. may be used.

This device differs the microwave power density irradiated from the power feeding parts 1a to 1c such as multiple waveguides (or similar horns and antennas) for each feeding part, and adjusts the load amount at each position. Microwave heating efficiency is good because heat treatment can be performed in accordance with heating conditions.

For example, if the object to be heated is still in a liquid state and has a relatively large volume, the microwave loss coefficient Eetan δ (E is the dielectric constant of the material, δ
is the dielectric loss angle of a material, and the microwave power loss in a certain material is proportional to Etan δ.

) is large, the microwave absorption is good even if the microwave power density is small, but the load is small (Etan
As δ becomes smaller, the absorption of microwaves decreases at the same power density, so it is necessary to increase the microwave power density for efficient heating.

In order to change the microwave power density in the power feeding section, for example, when the supplied microwave output is kept constant, this can be easily solved by changing the dimensions of the irradiation section.

Further, by providing an oven in the power supply section and changing the size of the oven for each power supply section, the microwave power density can be changed.

In addition, if a very large microwave power density is required due to the amount of material to be heated, 1 tan δ, there may be problems with discharge or leakage in an empty load state. As shown in FIG. 2, the supplied microwave energy can be absorbed by the end matching load 8.

If this method is adopted, it is possible to prevent discharge and leakage even with considerably high-density microwave power.

On the other hand, if the supply microwave power density is insufficient by changing the dimensions of the irradiation port, or if you want to change the power density without changing the irradiation port, use a back plunger 9 at the end to make the microwave resonate with the load. It is also possible to have an additional structure.

FIG. 3 shows its cross-sectional view. In these cases, metal (stainless steel, corrosion-resistant aluminum, etc.) is used to fabricate the turntable groove, but a dielectric material with low microwave loss can also be pasted on the inner surface of the groove.

Dielectric materials with relatively good heat resistance (Teflon, glass, etc.)
If it is possible to attach the object to be heated, it will be possible to install the object to be heated in the optimum position for microwave heating, reduce heat loss due to heat radiation, and furthermore, it will be easier to prevent sticking.

This device improves the microwave absorption efficiency of the dielectric material by changing the irradiated microwave power density even if the supplied microwave power is constant.
Microwave heating efficiency is good because it can be adapted to shape changes, and product uniformity is good because it is continuous.

Although the above explanation deals with changing the microwave power density, it is possible to change the microwave power supplied to each power feeding section by inserting an attenuator or a power branch circuit in the feeding section, or to change the microwave power density supplied to each feeding section. It goes without saying that the same effect can be obtained by keeping the wave power constant and changing the mounting positions of the respective power feeding parts on the circumference to change the heating microwave power distribution on the circumference.

Furthermore, this method can be applied not only to the solution but also to the continuous heating and drying of powder and granules.

Furthermore, by tilting the turntable slightly with respect to the rotation axis or together with the device itself, and by appropriately selecting the tilt angle and rotation speed (depending on the viscosity of the solution and the amount of precipitation), it was possible to ensure that the liquid part was always at the bottom and evaporated and precipitated. The solids are conveyed upwards.

This can be heated and dried by the method described above during transportation.

In this way, when the liquid part and solid matter are separated during evaporation, the finished product is good because it can be treated separately.

As explained above, it is possible to provide a continuous heating device that can accommodate changes in load and shape due to evaporation and drying of the solution, resulting in good uniformity of the microwave utilization efficiency product.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the device of the present invention, where a is a plan view or a front view, Fig. 2 is an explanatory diagram of an example of application of the microwave irradiation section of the device of the present invention, and Fig. 3 is an explanatory diagram of another example of the device. It is an explanatory diagram of an application example. 1a to 1c...Microwave waveguide power feeding section, 2.
... Turntable, 3 ... Groove-shaped container, 4 ... Microwave leakage prevention section, 5 ...
・Motor, 6...Liquid inlet, 7...Product outlet.

Claims (4)

[Scope of utility model registration request] (1) A series of groove-shaped containers provided along the periphery of the turntable, an inlet and an outlet for the heated material provided at predetermined positions of the groove-shaped container, and a series of groove-shaped containers provided in the vicinity of the groove-shaped container. a plurality of power supply parts arranged to irradiate a part of the groove-shaped container with microwave power, and at least one of the plurality of power supply parts has a density of irradiated microwave power different from that of the other power supply parts. A microwave heating device characterized by: (2) A request for utility model registration in which the mounting positions of multiple power supply parts are arranged at unequal distances on the circumference of the turntable and a means is provided to change the irradiation area or the opening area of the power supply part. Microwave heating device according to scope 1. (3) A part of the side wall of the power feeding part is extended into the container, a part of the inner wall of the container forms a microwave carrier path, and the other end of the carrier path is terminated with a matching load or a back plunger. A microwave heating device according to claim 1, which has been registered as a utility model. (4) The microwave heating device according to claim 1, wherein the direction of the main surface of the turntable is slightly inclined with respect to the rotation axis.