Equipment

Abstract

Provided is an equipment having a safety mechanism in hardware. The equipment is arranged such that a third relay (9) is controlled by a third contact driving circuit (11) as hardware so that an igniter (2) and a fuel supply valve (3) become operable when a blower is operated and a certain amount of time elapses. The equipment is arranged so as to complement drawbacks of software by the safety mechanism of hardware. The third contact driving circuit (11) is composed of a voltage multiplying rectifier circuit (27) containing a time constant circuit (13), an oscillating circuit (28) on a secondary side of the voltage multiplying rectifier circuit (27), a contact driving part (relay driving circuit) (37) on a secondary side of the oscillating circuit (28), and the like. The third relay (9) is connected to a part of the contact driving part (37).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a schematic circuit diagram showing a first embodiment of the present invention;

FIG. 2 is a flowchart for explaining operations of control such as pre-purge;

FIG. 3 is a schematic circuit diagram showing a second embodiment of the present invention; and

FIG. 4 is a flowchart showing a conventional pre-purge control by means of software.

Claims

1. An equipment, comprising: a first device;at least one second device; anda circuit system having a first contact, a second contact, and a third contact, wherein:the circuit system has a circuit structure in which the first device on a secondary side of the first contact is operated when the first contact is turned on, and at least one second device on a secondary side of the second contact is operated when the second contact is turned on;the third contact is provided on a primary side of the second contact; andthe third contact is turned on by a third contact driving circuit containing a time constant circuit.

2. An equipment according to claim 1, wherein the third contact driving circuit comprises a voltage multiplying rectifier circuit which has the time constant circuit and to which a pulse signal is inputted, and an oscillating circuit provided on a secondary side of the voltage multiplying rectifier circuit.

3. An equipment according to claim 1 or 2, wherein: the first contact and the second contact are turned on based on a control signal from control means; andonly turning on of the third contact is carried out by the third contact driving circuit.

4. An equipment according to claim 3, wherein: a fourth contact which is turned on upon detection of operation of the first device is provided on a primary side of the third contact; andthe control means monitors an on-state of the fourth contact.

5. An equipment according to claim 4, wherein the control signal for turning on the first contact is generated after judging by the control means that the fourth contact is in an off-state.

6. An equipment according to claim 5, further comprising a second voltage multiplying rectifier circuit for multiplying and rectifying the control signal for turning on the first contact, the second voltage multiplying rectifier circuit being used as a power supply for the third contact driving circuit.

7. An equipment, comprising: a first device;at least one second device;a circuit system having a first contact, a second contact, and a third contact; andcontrol means for generating a control signal for turning on the second contact based on counting of an internal timer in software, wherein:the circuit system has a circuit structure in which the first device on a secondary side of the first contact is operated when the first contact is turned on, and at least one second device on a secondary side of the second contact is operated when the second contact is turned on;the third contact is provided on a primary side of the second contact; andthe third contact is turned on by a third contact driving circuit containing a time constant circuit.

8. An equipment, comprising: a circuit structure in which a first device on a secondary side of a first contact is operated when the first contact is turned on, and at least one second device on a secondary side of the second contact is operated when the second contact is turned on;a third contact provided on a primary side of the second contact;control means for generating a control signal for turning on the third contact based on counting of an internal timer in software to turn on the third contact; anda circuit system for turning on the third contact by a third contact driving circuit containing a time constant circuit when the control means is in an abnormal state.

9. An equipment according to any one of claims 1 to 8, wherein the third contact driving circuit comprises a fail-safe circuit.

10. An equipment according to any one of claims 1 to 9, wherein the circuit system is used for pre-purge of a thermal equipment.