JPS589886B2 - Microwave oven with hot air circulation oven - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave oven with a hot air circulation type oven.

Microwave ovens with ovens have become popular, but due to the current electricity situation in ordinary households in Japan, simultaneous heating with ovens and high-frequency waves is not possible.

In this point, if gas is used as a heat source, there is no problem in terms of capacity for simultaneous heating.

However, a microwave oven equipped with a gas oven has not yet been realized, and various technical problems can be considered, one of which is the problem of cooling.

Conventionally, microwave ovens pass cooling air from a magnetron or the like through a heating chamber to exhaust steam generated from food during high-frequency heating to prevent condensation from forming on the walls of the heating chamber.

However, if this method is directly adopted in a microwave oven equipped with a gas oven, the following two problems will occur.

One is a decrease in the temperature inside the refrigerator. The upper limit of magnetron cooling air is probably a little over 100℃, so 250℃~30℃
If it is introduced into a heating chamber at 0°C, the internal temperature will drop significantly.

Another problem is to change the combustion state of the gas.

Unless a heat exchanger is used to send only heat into the heating chamber, the air in the heating chamber will affect the combustion of the gas, but if the amount of air introduced into the heating chamber changes depending on whether high frequency is being generated or not. , the combustion state of the gas is greatly affected.

As is well known, there are 15 types of gas used in general households in Japan, and combusting all of them safely and reliably is a major challenge when designing a gas oven.
If changes in air volume are added to this, the range that can be satisfied in terms of design will greatly expand, creating a major problem.

The present invention aims to solve this problem and realize simultaneous heating using an oven and high frequency.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a heating chamber and a heat source box.

The heating chamber 10 is formed by welding and enameling iron plates approximately 0.8 mm thick, and is integrally molded with two protruding shelves on the left and right walls, and a high-frequency wave is introduced into the center of the upper surface. A hole 12 is opened, and a waveguide, which will be described later, is screwed into the small hole made around the hole.

The heating chamber back plate 20 is made of an enameled iron plate with a diameter of about <0.8.

A metal disc 24 is removably attached, having a group of small blowing holes 21 on the left and right sides, a group of small discharge holes 22 on the top, and a group of small suction holes 23 in the center.

The heat source box 30 is made by welding aluminized steel plates with a thickness of about 0.8 mm, and has a hot air circulation fan 31 in the center and a gas burner 32 in the lower part.

The inside of the box is separated by three partition plates.

The upper partition plate 33 is horizontally fixed above the fan 31, and its position corresponds to the boundary between the blowout hole group 21 and the discharge hole group 22 of the heating chamber back plate 20.

The lower partition plate 34 is fixed horizontally between the fan 31 and the gas burner 32.

The central part of the heating chamber back plate side has a rectangular notch, located at a position corresponding to the lower end of the group of small blowing holes.

The middle partition plate 35 is located between the upper and lower partition plates, has a U-shaped cross section, and is fixed vertically.

The size of the U-shape matches the rectangular cutout of the lower partition plate 34, and a large circular hole is formed in the portion facing the hot air circulation fan 31.

An elongated rectangular exhaust hole 36 is formed in the top surface of the heat source box, and a circular small hole 37 for intake is formed in the bottom surface.

FIG. 2 is a perspective view of the body of this embodiment with the right side and top surfaces removed, showing the interior of the machine room.

The machine room is located on the right side of the heating chamber, and is separated by a metal upper and lower partition plate 4.
Divided into upper and lower sections with 0.

Pine end 41, Gaskotoku 42, Governor 4 on the lower side
3. Arrange gas components such as the solenoid valve 44.

Above the upper and lower partition plates, there is a magnetron 51, a waveguide 52,
High voltage transformer 53, phase advance capacitor 54, machine room cooling fan 55, fan motor 56, time switch 5
Electric components such as T and an interior light 58 are arranged.

The rotating shaft of the fan motor 56 protrudes from both sides of the motor.
The cooling fan 55 is fixed to one side, and a first pulley 61 made of polyacetal resin is fixed to the other side, which passes through the body back plate 60.

A group of small holes 62 for sucking cooling air are formed in the back plate 60 around this.

A rubber belt 63 made of neobutane rubber is wrapped around the pulley 61, and this rubber belt is connected to a second pulley 64.

Figure 3 is a perspective view of a portion of the second pulley taken out.
The second pulley 64 is made of polysulfone resin and is fixed to a fan shaft 65 made of stainless steel.

The fan shaft is rotatably fixed by a shaft mounting plate 66 made of two metal plates.

A bearing 67 made of glass fiber-based fluorinated resin is inserted between the shaft mounting plate 66 and the fan shaft 65.

The tip of the fan shaft is D-cut and threaded.

The hot air circulation fan 31 described above is attached here.

FIG. 4 is a right side view of this embodiment, and the right side plate of the body is divided into an upper plate 71 on the upper side and a lower plate 72 on the lower side of the upper and lower partition plate 40, each of which is provided with louvers 73 and 74. Each lower plate can be removed individually.

FIG. 5 is an electrical circuit diagram of this embodiment, in which the fuse 102 is connected next to the power plug 101, and then the interior light 1 is connected as usual.
03 (above 58) and the interior light switch 104 are connected,
Similarly, the ignition switch 115 and the ignition circuit 106 are connected.

After this, 3 is provided with a first door switch 107, a second door switch 108 and a third door switch 109 that are linked to the opening and closing of the door of the heating chamber, and then the contact 110 of the time switch (57) motor 111
Connect.

Next, the safety switch 112 that is linked to the attachment and detachment of the metal disk 24 is connected in parallel with the fan motor 113 (above 56).

After this, it branches into two, one is the microwave oven switch 11
4, and thereafter a microwave oven operation display neon lamp 115 and a high voltage transformer 116 (above 53) are connected in parallel.

Note that the secondary side of the transformer is omitted.

The other is an oven switch 117, which is connected in parallel with an oven operation display neon lamp 118, and then a thermostat 1.
19, preheating indicator neon lamp 120, bridge rectifier 1
21 and a solenoid valve 122 (above 44) are connected.

Note that a second ignition switch 123 having a B contact is connected in series with this.

Further, both the ignition switch 105 and the second ignition switch 123 are linked to the gas tank 42.

Both the oven switch and the microwave switch shall use NO contacts.

With the above configuration, a microwave oven that can be used for oven cooking and high frequency cooking simultaneously is completed.

The gas flame burned by the burner 32 passes through the rectangular notch in the lower partition plate 34 and the large circular hole in the middle partition plate 35, is sucked into the center of the circulation fan 31, and is blown out from the periphery, forming a group of small blowing holes. Pass through 21 and enter the heating chamber.

When it circulates in the heating chamber, it passes through the small suction hole group 23 and is sucked into the center of the circulation fan 31 again.

A portion of the hot air circulating within the heating chamber passes through the small exhaust hole group 22 and is exhausted to the outside from the exhaust hole 36.

Fresh air necessary for combustion of the gas is taken in through a small air intake hole 37 on the bottom of the heat source box.

Air for cooling the machine room is sucked through a group of small holes 62 on the back plate of the body, and is discharged through louvers 73 and 74 on the side plate of the body.

Since the air flow for gas combustion and the air flow for cooling the machine room are completely separated in this way, the above-mentioned problem does not occur when high frequency and gas are simultaneously heated.

Furthermore, since the exhaust small hole group 22 is provided on the back plate 20 of the heating chamber, all of the hot air sucked in by the fan 31 is exhausted through the heating chamber, resulting in good thermal efficiency and particularly excellent initial rise characteristics.

Furthermore, since the machine room cooling fan rotates even during gas combustion, the reliability of phase advance condensers, etc., which are particularly sensitive to heat, can be ensured.

In the case of high-frequency heating only (gas is not combusted), air is circulated within the heating chamber by the rotation of the circulation fan, and some of it is exhausted from the small exhaust hole and the air intake hole. It can be taken in through the hole.

Therefore, the steam emitted by the food is carried out of the heating chamber together with the exhaust air.

According to this embodiment, when the door is closed and the time switch is turned on, the fan motor is energized and the cooling fan rotates.
A circulation fan connected by a rubber belt also rotates at the same time.

In other words, one fan motor can be used for high-frequency heating, gas combustion, and at the same time.

Further, the rubber belt is provided outside the body back plate, but even if the inside of the body becomes hot during gas combustion, the rubber belt can be used because the heat is cut off by the body back plate and it is in contact with the outside air.

In addition, the higher the rotation speed of the cooling fan, the better the cooling effect, so as long as vibrations and noise do not occur, it is preferable, but the rotation speed of the hot air circulation fan affects the combustion of gas and the degree of operation, so the rotation speed should be set higher or lower. Both are subject to restrictions.

Therefore, in the conventional hot air circulation type gas oven, a long time was required to design the circulation fan and the motor that drives it, but when the fan motor is connected by a pulley as in this example, the fan motor has a small capacity. If a large fan is used, the rotation speed of the circulation fan can be easily changed by changing the pulley ratio.

When comparing a cooling fan and a circulation fan that are conventionally used, the torque required for rotation of the cooling fan is larger.

Therefore, when used as in this embodiment, the rotation speed of the fan motor is mainly determined by the cooling fan.

Although the above description has been about a gas oven, it is also possible to heat the oven simultaneously with high frequency using electric heat if a method such as using a 200mm power source is used.

This can be easily realized by connecting a heater in place of the solenoid valve shown in FIG. 5 and placing the heater in place of the gas burner shown in FIG.

Even in that case, the present invention is effective. As described above, according to the present invention, it is possible to heat the oven and the high frequency simultaneously, and all the hot air from the fan is exhausted through the heating chamber, so the thermal efficiency is high, and the rise characteristics especially at the initial stage of heating are excellent. Since the machine room cooling fan rotates even when gas is burned, heat-sensitive components such as the phase advance condenser are sufficiently protected, making it possible to provide a highly reliable microwave oven with hot air circulation type oven.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of a heating chamber and heat source box showing one embodiment of the present invention, Fig. 2 is a perspective view of the machine room from the right side, and Fig. 3 is a perspective view of one drive section of the circulation fan. 4 is a right side view of the same, and FIG. 5 is an electric circuit diagram of the same. 31...Hot air circulation fan, 55...Machine room cooling fan, 30...Heat source box, 10...Heating chamber, 60,71.72
... Body, 21 ... Small hole group for blowing, 23 ... Small hole group for suction, 56 ... Fan motor, 61 ... → first pulley, 64 ... second pulley, 63 ... Five rubber belts, 113
...Fan motor, 114 ...Microwave oven switch,
117...Oven switch

Claims (1)

[Claims] 1. A hot air circulation fan, a machine room, a machine room cooling fan, a heat source box, a heating chamber, a body, a madanetron, and a heat source for a hot air circulation oven, and the hot air circulation fan is connected to the heat source. In the box, the machine room cooling fan is provided in the machine room, the heat source box and the heating chamber are connected through a ventilation hole, and an intake hole is provided in the lower part of the heat source box, and an exhaust hole is provided in the wall surface of the heating chamber. The machine room is separated from the heating chamber, and the hot air circulation fan and the machine room cooling fan are rotated simultaneously when the magnetron is activated or the hot air circulation oven is heated. range.