JPH03119687A - fluid heating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for efficiently heating a fluid, such as a fluid heating device suitable for heating window dressing fluid of automobiles used in cold regions.

C. Prior Art] Typical heating devices using microwaves are currently
It's a microwave. In a microwave oven, microwaves emitted from a magnetron are placed inside a metal-X oven and heat the food that is inserted into the oven.

Typically, the thermal efficiency of a microwave oven is about 50%, meaning that only 50% of the input power can be used for heating. However, the magnetron itself has an efficiency of 68% or more during impedance matching. In addition, the heat loss occurring at the magnetron anode is 25
% is wasted, but if we can utilize this, we should be able to increase the thermal efficiency to 80% or more.

Conventional heating devices using magnetrons assume that the magnetron is attached to a waveguide or oven that guides microwaves, and a gasket made of braided thin metal wire is used to prevent microwaves from leaking from the connection point. Therefore, when one magnetron is used to heat a fluid, a fluid heating chamber that prevents the fluid from flowing out must be provided separately from the magnetron.

[Problems to be Solved by the Invention] The conventional magnetron or microwave heating device described above cannot be used as is as a fluid heating device, for example, a device for heating window dressing fluid for automobiles used in cold regions.

An object of the present invention is to provide a fluid heating device that has a fluid heating chamber with a volume of 200 to 2000 cc and can convert electric power into heat with higher efficiency than a conventional microwave oven or the like.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a leak prevention means (for example, on the side of the magnetron) surrounding the antenna and having a volume of 200 to 2000 cc at the connection part with the magnetron main body.
A ring-shaped part for this seal is added, and each connection is connected by a method such as brazing or welding to prevent microwaves and fluid from flowing out).A fluid heating chamber is provided to radiate microwaves. The fluid passes through a fluid heating chamber surrounding the entire circumference of the antenna, and in a normal microwave oven, heat generated due to power loss at the magnetron anode is cooled by air, but in the device of the present invention, the main body of the magnetron is heated. The structure is such that the anode directly contacts the fluid to be treated and is cooled by the fluid passing through the anode cooling means, so that 25% of the heat loss that was wasted in the past can be used as a heat source for preheating the fluid.

[Operation] When heating a liquid with microwaves, if a normal microwave oven is used as is, the microwaves emitted from the magnetron pass through the waveguide, causing loss on the inner surface of the waveguide.

Further, the portion where the waveguide is guided into the oven becomes discontinuous, causing two reflections and a loss. In addition, the receiver inside the oven causes loss as it reflects off the tray, the inner wall of the front door, and the oven wall. Then, even in the container containing the liquid to be heated, the liquid is finally reached, with losses occurring.

On the other hand, in the device of the present invention, the antenna part of the magnetron is placed in the liquid (fluid), so that all the radiated microwaves enter the liquid. When the microwave passes through the liquid and reaches the wall of the cavity, it has been greatly attenuated, so the loss at the cavity wall, where the loss rate is the same, is less, and the heat generated at the anode can also be used to preheat the fluid. can further increase efficiency.

[Embodiment] FIG. 1(a) is a partially sectional top view of an embodiment of the present invention, and FIG. 1(b) is a partially sectional side view of the same embodiment. The fluid heating chamber 1 has a cavity dimension that resonates at an integral multiple of a quarter wavelength of the microwave used. As a result, the load is coupled to the magnetron 2 in a well-matched state.

Microwaves are most efficiently absorbed by fluids. Microwaves are radiated from the magnetron's antenna 4, which is surrounded by an antenna dome 3 made of ceramic insulator and placed in a vacuum.

In the direction of the arrow, the fluid first flows into the PJjIti cooling means 5, cools the anode of the magnetron, and then the fluid itself rises in temperature and is preheated, flows into the fluid heating chamber 1, is heated by microwaves, and then enters the main heating device. Leave in the direction of the arrow.

The entire fluid heating device is kept warm with a heat insulating material as necessary.

A particular problem with the apparatus of the present invention is the means for preventing fluid outflow at the connection between the fluid heating chamber and the magnetron. A conventional magnetron for microwave ovens has a structure as shown in the partially sectional side view of Fig. 2, in which there is a gas scale consisting of many layers of braided mesh of thin metal wires at the bottom of the antenna dome 3. 1-12 are arranged. This gasket is used to make good electrical contact with the metal of the waveguide, and pressure is applied when contact is made, and after installation, the state is as shown in Figure 3 (,).

In contrast, the device of the invention not only requires good electrical contact but also must be fluid-tight. As shown in FIG. 3(b) or (Q), the method used in this example is to arrange a seal ring 10-1 or 10-2 on the metal part of the lower part of the antenna dome of the magnetron to seal the fluid heating chamber. This is to attach the part. The seal ring and the fluid heating chamber are connected using methods such as soldering, hard brazing, or arc welding.

[Effects of the Invention] As explained above, according to the present invention, a small and large microwave power can be applied directly to a fluid.
Suitable as a fluid heating device for applications where the temperature of the fluid increases quickly and it is necessary to rapidly raise the temperature of a small amount of fluid.For example, in cold regions, it is suitable as a fluid heating device for heating car window dressing fluid to defrost windshields. A device is obtained.

[Brief explanation of drawings]

FIG. 1(a) is a partially sectional top view of one embodiment of the present invention, FIG. 1(b) is a partially sectional side view of the same embodiment, and FIG. 2 is a conventional microwave oven. The installation of the magnetron in a heating device is shown in a partial structural diagram. Figure 3 (a) is a diagram showing the state of the installation after the magnetron is installed in a conventional microwave heating device. Figures 3 (b) and (c) 2 is a partial structural diagram showing the magnetron installation in the heating device of the present invention. 1... Fluid heating chamber, 2... Magnetron,
3... Antenna dome, 4... Antenna, 5.
... Anode cooling means, 6... Heat insulating material, 7... Magnet, 8... Yoke, 9... Waveguide wall, 10-
1.10-2... Seal ring, 11... Heating chamber wall, 12... Gasket φ-53- 2nd Figure 12-rl゛Matsuba, 7th

Claims (1)

[Claims] 1. In a device that uses a magnetron as a microwave oscillation source and heats a fluid with the microwaves radiated from the magnetron's antenna, a volume of 2
00 to 2000 cc, a fluid heating chamber equipped with an outflow prevention means is provided at the connection part with the magnetron main body, and the fluid passes through the fluid heating chamber while surrounding the entire circumference of the antenna that radiates microwaves, and the main body of the magnetron is A fluid heating device characterized in that the fluid is preheated by being in direct contact with the fluid to be heated and being cooled by the fluid passing through an anode cooling means.