JPH1022069A - Glow heater device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glow heater device to which power can be input when it is grounded by detecting whether or not it is grounded. SOLUTION: This device includes an ac power supply part 1 which supplies power to a glow heater 4 by which an input subject for heating is heated by heat produced by a glow discharge and is output, a conductive case 13 covering the glow heater and the ac power supply part 1 and engaged with the subject for heating in such a way as to have the same potential as the subject for heating, and an earth detection means 12 which electrically connects the case 13 to the ac power supply part 1 to detect whether or not the case 13 is grounded 14; when the case 13 is grounded, the power can be input to the glow heater 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glow heater device, and more particularly to a glow heater device for detecting whether or not the case is grounded.

[0002]

2. Description of the Related Art FIG. 8 shows, for example, Japanese Patent Application Laid-Open No. 54-94137.
FIG. 1 is a circuit diagram illustrating a configuration example of a glow heater device disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-15095. 1 is an AC power supply, 2 is a step-up main transformer having a center tap on a secondary winding, 3a and 3b are diodes each having a cathode connected to both ends of a secondary winding of the main transformer 2, 4 is a glow heater, 41, 42 are discharge electrodes, 4
3 is the grid electrode, 5 is a resistor connected between the center tap of the secondary winding of the main transformer 2 and the grid electrode 43, 6 is a start button switch, 7 is a relay coil,
71 and 72 are relay contacts, 8 is a push button switch for stopping, 9 is a control circuit for controlling activation and operating temperature of the glow heater 4, 10 is an auxiliary transformer for supplying power to the control circuit 9, and 11 is a control circuit 9 A high-voltage pulse generating circuit for supplying a high-voltage pulse to the grid electrode 43 in response to a start signal from the controller to start the glow discharge of the glow heater 4, and a heat-sensitive element 20 such as a thermistor for detecting the temperature in the tank of the glow heater 4. .

Next, the operation will be described with reference to the drawings. In this glow heater device, first, when the start push button switch 6 is closed, a current flows through the relay coil 7 and the relay contact 7
1 and 72 are closed, the relay coil 7 is self-held, the control circuit 9 is operated via the auxiliary voltage generator 10, and the high-voltage pulse generating circuit 11 generates a high-voltage pulse voltage. Since this high-voltage pulse voltage is superimposed on the voltage boosted by the main transformer 2 and applied to the grid electrode 43, a glow discharge occurs between the discharge electrodes 41 and 42. The object to be heated housed in the tank of the glow heater 4 is efficiently heated by the heat generated by the glow discharge. The temperature in the tank of the glow heater 4 is detected by the thermal element 20 and is controlled by the control circuit 9. To stop the operation of the device, the relay 7 is restored by pressing the stop push button switch 8, the contacts 71 and 72 are opened, and the device stops operating.

[0004]

Since the conventional glow heater device is constructed as described above, the case of the glow heater device is used with the case grounded. However, the glow heater device operates even if the case is not grounded. So I forgot to ground,
There were problems such as incomplete grounding.

The present invention has been made in order to solve the above-mentioned problems, and provides a glow heater device capable of turning on power when grounded by detecting the presence or absence of grounding (earth). The purpose is to:

[0006]

A glow heater device according to the present invention includes a glow heater for heating and outputting an input object to be heated by the heat generated by glow discharge, an AC power supply for supplying power to the glow heater, A conductive case that covers the glow heater and the AC power supply unit and engages with the object to be heated, and an earth detection unit that electrically connects the case and the AC power supply unit to detect whether the case is grounded. Means for supplying power to the glow heater when grounding of the case is detected by ground detection means.

In the glow heater device according to the next invention, the ground detecting means detects the presence or absence of grounding of the case by measuring the current between the AC power supply unit and the case.

In the glow heater device according to the next invention, the ground detecting means detects the presence or absence of grounding of the case by measuring the resistance between the AC power supply unit and the case.

Further, in the glow heater device according to the next invention, the ground detecting means detects the presence or absence of grounding of the case by measuring the voltage between the AC power supply unit and the case.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an embodiment of a glow heater device of the present invention will be described with reference to the drawings. In FIG. 1, 1 is an AC power supply, 4 is a glow heater, 41 and 42 are discharge electrodes thereof, 43 is a grid electrode, 9 is a control circuit for controlling activation and discharge of the glow heater 4, and 12 is whether the glow heater device is grounded. These are earth detection circuits for detection, which are housed in a conductive case 13.
Reference numeral 14 denotes a ground, which is connected to the case 13. The glow heater device 15 is grounded by a ground 14 via a case 13. In this embodiment, components that are not directly related to the description of the present invention, such as the transformers 2 and 10, the high-voltage pulse generating circuit 11, the button switch 6, the relay coil 7, the thermistor 20, and the resistor 5 shown in FIG. Omitted. FIG. 2 shows a fluid to be heated through the glow heater 4 and a system such as a valve for utilizing the fluid. In addition, the water as the fluid to be heated passing through the discharge electrode of the glow heater 4 is grounded by the ground 14 via a valve or the like in the water passage.

Next, the operation of the glow heater device 15 of the present invention will be described with reference to the drawings. A high-voltage pulse is applied to the grid electrode 43 from the control circuit 9 to light a pilot flame inside the glow heater 4. When the pilot lamp is turned on, the discharge voltage of the glow discharge becomes lower than the voltage applied from the AC power supply 1 to the discharge electrodes 41 and 42.
Glow discharge occurs. The user of the glow heater device 15 utilizes the fluid to be heated which is heated through the glow heater 4. An example of use is an instantaneous water heater. Since the glow heater 4 operates as described above, the heated fluid used by the user is in direct contact with the electrode and is charged. However, it is safe if the fluid to be heated is at ground potential before touching the user. The ground detection circuit 12 detects whether the case 13 of the glow heater device 15 is grounded by the ground 14.

Next, the operation of the ground detection circuit 12 will be described. FIG. 2 is a conceptual diagram of the glow heater device 15, and FIG.
The same reference numerals denote the same or corresponding parts, and a description thereof will be omitted.
2, the control circuit 9 shown in FIG. 1 is omitted.
FIG. 3 is a flowchart showing the operation of the low heater device 15. In FIG. 2, 16 is a fluid to be heated, 17 is a main switch for turning on / off the power of the AC power supply 1 to the glow heater 4, and 18a and 18b are valves. The fluid to be heated 16 is guided from the outside to the glow heater device 15 through the valve 18a, and is heated through the glow heater 4.
Further, the gas is discharged from the glow heater device 15 through the valve 18b and used for utilization. Valves 18a and 18b
Is fixed to the case 13 and electrically connected to the case 13.
And the same potential. Therefore, the heated fluid 16 that has passed through the glow heater 4 passes through the valves 18a and 18b, and thus has the same potential as the case 13. In FIG. 3, first, a start is performed to operate the glow heater device 15. For example, turning on the AC power supply 1 or the control circuit 9 or putting the fluid 16 to be heated into the glow heater 4. At the same time as the start, the ground detection circuit 12 determines whether the case 13 of the glow heater device 15 is grounded (step S1). When it is determined that the AC power supply 1 is grounded, the earth detection circuit 12 turns on the main switch 17 to operate the glow heater device 15 (step S2). The power supply to the glow heater 4 is blocked, and the glow heater device 15 is not operated (step S3).

Next, a method of detecting the presence or absence of the ground by the ground detection circuit 12 will be described. FIG. 4 is an explanatory diagram of a method of detecting the presence or absence of ground by detecting a ground current. In the drawing, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts. In FIG. 4, reference numeral 1 denotes an AC power supply, which is generally wired and transmitted for three-phase three-wire 200 V or single-phase three-wire 100 V.
(Or 200 V), and the middle line of the three-wire system is provided with the second-class grounding. Further, 1a is provided in the case 13, and is an AC power supply unit for drawing power from the AC power supply 1 to the glow heater device 15, 1b is a terminal of the AC power supply unit, 21 is a resistor, and 22 is an ammeter. The resistor 21 and the ammeter 22 are provided in the ground detection circuit 12a, and are connected to the non-ground line of the AC power supply 1 and the case 13. Case 13 is ground 1
4, the case 13 and the object to be heated 16 are connected to the valves 18a and 18 so that they have the same potential as shown in FIG.
b. Other parts of the glow heater device 15 are omitted.

Next, the operation will be described with reference to FIG. This earth detection method detects the presence or absence of earth by measuring a current. In FIG. 4, case 13
Is grounded by the ground 14, a voltage of 100 or 200 V is applied to both ends of the ground detection circuit 12a. Therefore, the current flowing through the ammeter 22 is determined in a predetermined range by the voltage of the non-ground line, the resistance value of the resistor 21, and the ground resistance. However, if the case 13 is not grounded, it will be at a floating potential, so that different current values will be measured, and the presence or absence of grounding by the grounding 14 can be detected. Although FIG. 4 shows an example in which the resistor 21 is used, the current may be measured using a photocoupler, a diode, a transistor, or the like.

FIG. 5 is an explanatory diagram of a method of detecting the presence or absence of ground by detecting a ground resistance. In the drawing, the same reference numerals as those in FIG. 4 indicate the same or corresponding parts. In FIG. 5, the middle line of the AC power supply 1 is grounded in two types. A resistance meter 23 is provided between the center line and the case 13. If the case 13 is grounded by the ground 14, a resistance value within a predetermined range is measured. If the case 13 is not grounded, a large resistance value is measured, and the presence or absence of grounding can be detected.

FIG. 6 is an explanatory diagram of a method of detecting the presence or absence of ground by detecting a voltage. In the drawing, the same reference numerals as those in FIG. 4 denote the same or corresponding parts. In FIG. 6, an AC power supply 1
A voltmeter 24 is provided between the power supply and the case 13. If the case 13 is grounded by the ground 14, a voltage of 100 or 200 V (0 V when connected to the middle line) is applied to both ends of the ground detection circuit 12c. If the case 13 is not grounded by the ground 14, the floating potential will be attained, so that a different voltage will be measured, and the presence or absence of the ground can be detected.

FIG. 7 is an explanatory diagram of a method of detecting the presence or absence of ground by detecting voltage and current. In the figure, the same reference numerals as those in FIG. 4 indicate the same or corresponding parts. In FIG. 7, a resistor 21 is connected in series in the ground detection circuit 12d.
The voltage is measured at both ends by a voltmeter 24, and the current is measured by an ammeter 22 connected in series to the resistor 21, and the presence or absence of the ground is detected based on the measured voltage and current.

[0018]

As described above, according to the present invention, in the glow heater device, the presence or absence of grounding of the case is detected by electrically connecting the conductive case and the AC power supply unit engaged with the object to be heated. Equipped with ground detection means, and when the ground detection means detects grounding of the case, it is possible to supply power to the glow heater. It is possible to provide a glow heater device that can be used safely.
Also, there is an effect that the presence or absence of grounding can be detected at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a glow heater device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a glow heater device according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of the ground detection circuit according to the embodiment of the present invention;

FIG. 4 is an explanatory diagram of a ground detection circuit that detects the presence or absence of a ground by detecting a current.

FIG. 5 is an explanatory diagram of a ground detection circuit that detects the presence or absence of a ground by detecting a resistance.

FIG. 6 is an explanatory diagram of a ground detection circuit that detects the presence or absence of a ground by detecting a voltage.

FIG. 7 is an explanatory diagram of a ground detection circuit that detects the presence or absence of a ground by detecting a voltage and a current.

FIG. 8 is a circuit configuration diagram showing a conventional glow heater device.

[Explanation of symbols]

1 AC power supply, 1a AC power supply section, 4 glow heater,
12 ground detection circuit, 13 case, 15 glow heater device, 14 ground, 16 fluid to be heated, 17
Switch, 18a, b valve,

Claims (4)

[Claims] 1. A glow heater for heating and outputting an input object to be heated by heat generated by glow discharge, an AC power supply unit for supplying power to the glow heater, and covering the glow heater and the AC power supply unit, A conductive case engaged with the heating object; and ground detecting means for electrically connecting the case and the AC power supply unit to detect whether or not the case is grounded. The glow heater device is capable of supplying electric power to the glow heater when is detected. 2. The glow heater device according to claim 1, wherein the ground detecting means detects whether or not the case is grounded by measuring a current between the AC power supply unit and the case. 3. The glow heater device according to claim 1, wherein the ground detecting means detects whether or not the case is grounded by measuring a resistance between the AC power supply unit and the case. 4. The glow heater device according to claim 1, wherein the ground detecting means detects whether or not the case is grounded by measuring a voltage between the AC power supply unit and the case.