JPH01190398A - Micro-wave drying equipment - Google Patents

Abstract

PURPOSE:To reduce a period of time for drying clothes by applying a magnetron, and to prevent electric discharges and scorches by breaking the electric supply circuit for the magnetron when ultrasonic microphones detect the presence of metals. CONSTITUTION:Clothes in a drying chamber are efficiently dried with high frequency waves transmitted by a magnetron 3. High frequency waves transmitted by a transmitter of high frequency ceramic microphone 8 travels through objects such as clothes in the drying chamber 1. While a part of the high frequency waves is absorbed, the other part is reflected by an external casing 2 of the drying chamber 1 and transmitted to the receiver of high frequency ceramic microphone 9. Since the reflection in case the waves travel through the objects consisting only of wet clothes to be dried is different from that in case they travel through the objects containing metals, there occurs some differences in high frequency wave signals to be received. Those data of differences are processed in a data processor 10, and when a metal is detected, a controller 11 shuts off the electric supply circuit for the magnetron 3 which transmits high frequency waves to the drying chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a clothes dryer that uses electricity as the heat source for heating and drying.In order to shorten the drying time, the present invention uses high-frequency radio waves, which are microwaves generated by a magnetron, as the heat source. This article relates to a high-frequency drying device, which is a household clothes dryer.

Conventional technology A conventional household clothes dryer sends hot air using an electric heater such as a PTC heater or a sheathed heater as a heat source into a rotating drum that forms a drying chamber, and circulates this hot air within the drying chamber. Home clothes dryers that use hot air to dry clothes using an electric heater as a heat source require time for the electric heater to reach a high temperature. It also takes time for the heated air to heat the drying chamber and the clothes to be dried to a certain high temperature. For this reason, clothes dryers using this electric heater as a heat source have the disadvantage that it takes a long time to dry clothes.

As a means to shorten this drying time, it is possible to use high-frequency radio waves, which are microwaves generated by a magnetron. When high-frequency radio waves, which are microwaves, are supplied as a heat source to clothes, which are items to be dried, the high-frequency radio waves directly heat the clothes. That is, the energy of the high frequency radio waves is converted into thermal energy of the clothing and the moisture it contains. Therefore, the drying time of clothes is greatly shortened.

High-frequency radio waves, which are microwaves, transmit the energy of alternating electric fields. If there is a metal object within an alternating electric field, an electric field is induced in the metal, causing phenomena such as causing discharge between the metals or inducing a stronger electric field at the ends of the metal object. If it is a dielectric material such as clothing or moisture, it is absorbed by the dielectric material due to dielectric loss and converted into thermal energy. Metal objects may be used for drying clothes. In the case of a clothes dryer that uses high-frequency radio waves (microwaves), if metal is used to dry the clothes, electrical discharge may occur due to the metal object, and the clothes may be burnt on the edge of the metal object. In order to shorten the drying time of a dryer, a magnetron is used, and high-frequency radio waves, which are microwaves, generated by the magnetron are used as a heat source, and the high-frequency electric field directly heats and dries the clothes to be dried. Metal objects contained in dried clothes are a problem when drying with high frequency radio waves. To prevent this, an ultrasonic microphone is used to detect metal objects using the ultrasonic waves, and the supply of high-frequency radio waves to the drying chamber is cut off.

To make it possible to utilize high frequency radio waves, which are microwaves, in a clothes dryer.

Function: When high-frequency radio waves are supplied to the drying chamber, the drying clothes there, including moisture, are dielectric, so they self-heat due to dielectric loss. If the water vapor generated by heating is discharged outside the drying chamber, the clothes can be dried in a short time.

An ultrasonic microphone is an element that both transmits and receives ultrasonic waves. The propagation conditions of ultrasonic waves change depending on the material. The propagation conditions change between low-density clothing or moisture and high-density metals, and some of the energy of the ultrasound that reaches the metal interface is absorbed, while the rest is reflected. If a metal object is detected based on a change in the propagation of the ultrasonic waves, if there is a metal object in the drying chamber, the power supply of high-frequency radio waves can be interrupted. A high-frequency drying device, which is a clothes dryer, using high-frequency radio waves such as microwaves can be obtained.

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

In Fig. 1, 1 is a drying chamber in which clothes are placed and subjected to high-frequency drying, and 2 is an external body of the drying chamber configuring the drying chamber 1, which leaks high-frequency radio waves, which are microwaves, supplied to the drying chamber 1 to the outside of the drying chamber 1. It is made of a thin metal plate. 3
4 is a magnetron which is a high-frequency oscillation source that supplies high-frequency radio waves to the drying chamber 1; 4 is a waveguide that transmits and supplies high-frequency radio waves oscillated from the magnetron 3 to the drying chamber 1; 5 is a waveguide that supplies power to the drying chamber 1;
This is the door for taking clothes in and out. The structure between the door 5 and the drying chamber outer body 2 is such that high frequency radio waves are supplied to the drying chamber 1 so that the high frequency radio waves do not leak therefrom during drying. Reference numeral 6 denotes a rotating drum provided in the drying chamber 1, which has a rotating shaft on the side wall of the drying chamber outer body 2, and rotates the clothes to be dried in order to increase drying efficiency. Since the rotating drum 6 is within the electric field of high-frequency radio waves, it is made of a resin material with little high-frequency loss, such as polypropylene. 7 is a drive motor for rotationally driving the rotating drum 6.

In the high-frequency drying apparatus of the present invention, the basic part of which is constituted by such a device, high-frequency microwave radio waves oscillated from the magnetron 3 are supplied to moisture-containing clothes in the drying chamber 1. If clothing or moisture, which is a dielectric material, is within the alternating electric field of high-frequency radio waves, the energy of the high-frequency radio waves is absorbed by the dielectric loss and converted into thermal energy. Unlike conventional hot air methods, instant heat is applied directly to the clothes and moisture to be dried, greatly shortening drying time. The clothes in the rotating drum 6 are rotated by a drive motor 7 during drying. This not only prevents uneven drying by placing the clothes evenly in the electric field of high-frequency radio waves, but also has the effect of discharging the water vapor generated from the clothes from a wide surface, which ultimately shortens the drying time. Become.

Reference numerals 8 and 9 denote a transmitting ultrasonic ceramic microphone and a receiving ultrasonic ceramic microphone, which are provided outside the drying chamber 1 at positions where ultrasonic waves can be propagated into the drying chamber 1. An ultrasonic ceramic microphone is an ultrasonic transducer that uses a piezoelectric ceramic as a vibrator to transmit and receive airborne ultrasonic waves. Reference numeral 10 indicates a transmission circuit for the transmitting ultrasonic ceramic microphone 8 to transmit ultrasonic waves into the drying chamber 1, and a receiving ultrasonic ceramic microphone 9 for detecting the ultrasonic signal inside the drying chamber 1. This is a signal processing section that includes a receiving circuit and a signal processing circuit for processing. Reference numeral 11 denotes a control circuit that receives control signals sent from the signal processing section 10 and controls oscillation and stopping of the magnetron 3 and other operations. Examples of ultrasonic transmitting circuits and receiving circuits are shown in FIGS. 2 and 3. FIG. 2 shows a transmitting circuit, which uses an oscillation circuit to transmit ultrasonic waves from the transmitting ultrasonic ceramic microphone 8. FIG. 3 shows a receiving circuit in which an ultrasonic signal is received by a receiving ultrasonic ceramic microphone 9, processed as information, and transmitted as a control signal.

The transmitting circuit and the receiving circuit are included in the signal processing section 10, which sends an oscillation signal for transmitting ultrasonic waves to the drying chamber 1, and processes information on the received ultrasonic signal as a control signal to the control circuit 11. Transmit to.

The control circuit 11 causes the magnetron 3 to oscillate, stop, and perform other operations in accordance with the control signal.

In the high-frequency drying apparatus of the embodiment of the present invention constructed as described above, the clothes in the drying chamber 1 can be efficiently heated and dried using the high-frequency radio waves generated by the magnetron 3. Ultrasonic waves are transmitted from the transmitting ultrasonic ceramic microphone 8 and propagated through a medium such as clothing in the drying chamber 1. A part of the ultrasonic wave is absorbed, but the other part is reflected by the drying chamber external body 2,
The waves are propagated to the receiving ultrasonic ceramic microphone 9. This ultrasonic signal becomes information that informs the situation inside the drying chamber 1. In ultrasonic waves, the propagation speed of sound waves depends on the properties of the medium; sound waves propagate more slowly in a medium with high density than in a medium with low density, and in a medium with high elasticity,
Propagates faster than in a less elastic medium. In addition, when an ultrasonic wave comes to a boundary between two different media, such as air and water, or air and metal, during the propagation process,
A portion of the sound energy enters other media in the form of ultrasonic waves, although the intensity is decreasing, and the other portion is reflected. Ultrasound travels best from solid to solid, liquid to liquid, and gas to gas. The passage from liquid to solid and thus from solid to liquid is much worse, and from gas to liquid or solid and vice versa it is quite bad.

Due to the properties of such ultrasonic waves, the ultrasonic waves transmitted from the transmitting ultrasonic ceramic microphone 8 are received by the receiving ceramic microphone 9 due to the difference in the medium of the object to be dried, such as clothes, in the drying chamber 1. undergoes various changes. There is a difference in reflection between when the object to be dried is a piece of clothing containing moisture and when there is a metal object inside, resulting in a difference in the received ultrasonic signals. If this is processed as an information source, metal objects can be detected and the supply of high frequency radio waves to the drying chamber 1 can be interrupted. Metal objects contained in dried clothes are a problem when dried using high frequency radio waves, but this can be prevented.

Effects of the Invention With the configuration of the present invention, high-frequency radio waves, which are microwaves, can be used as a heat source for household clothes dryers.
Since the clothes are directly heated and dried not by hot air but by the self-heating of the clothes, a high frequency drying device can be obtained which efficiently dries the clothes in a shortened time. Metals contained in the dried clothes are detected by an ultrasonic microphone and the high frequency radio wave power supply to the drying chamber is cut off, thereby preventing problems in the high frequency radio field and producing safe clothes.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a high frequency dryer showing an embodiment of the present invention, and FIGS. 2 and 3 are circuit diagrams of a transmitting circuit and a receiving circuit of an ultrasonic ceramic microphone used in the same device. 1...Drying chamber, 2...Drying chamber outer body, 3.
... Magnetron, 8... Ultrasonic ceramic microphone for transmitting, 9... Ultrasonic ceramic microphone for receiving. Name of agent: Patent attorney Toshio Nakao and one other person
Freezing 2 - Drying outer body 3... - Ma/j Netron 8.2 - Microphone Figure 1 Figure 2 Figure 3r1! J

Claims (1)

[Claims] A high-frequency drying device that includes a magnetron that supplies high-frequency radio waves to a drying chamber and an ultrasonic microphone that detects objects to be dried in the drying chamber, and that opens and closes power supplied to the magnetron using a detection signal from the ultrasonic microphone. .