# US 5,703,749 A · Safety control system responsive to carbon monoxide smoke and the like

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- Number: US 5,703,749 A
- Document ID: US5703749A
- Status: Granted
- Kind: A
- Application number: 08/735,097
- Filed: 1996-10-22
- Granted: 1997-12-30
- Earliest claimed: 1994-12-01
- Inventors: Romeo Prasad
- Web page: https://patentgrep.com/patent/US5703749A

## CPC

- G08B 21/14: Toxic gas alarms (G08B21/16 takes precedence)
- F23N 5/245: {using electrical or electromechanical means}
- F23N 5/003: {using detectors sensitive to combustion gas properties (F23N5/02, F23N5/18 - F23N5/26 take precedence)}
- F23N 2231/20: Warning devices
- G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- F23N: REGULATING OR CONTROLLING COMBUSTION (control devices specially adapted for combustion apparatus in which combustion takes place in a fluidised bed of fuel or other particles F23C10/28; condition responsive controls for regulating combustion in domestic stoves with open fires for solid fuel F24B1/187)

## Abstract

Apparatus is disclosed for preventing injury to an occupant of an enclosed space as the result of exposure to a noxious gas. The apparatus shuts a source of noxious gases, when an unsafe ambient condition is sensed. More particularly, the unsafe condition is typically the presence of the noxious gas in the enclosed space. In some forms of the invention the apparatus also includes structure for latching that upon sensing an unsafe condition continues to send a signal to shut off the source of noxious gas. Some forms of the apparatus may further include an override for the latching aspect of the structure. The override may be a manually operated push button that operates a relay. The apparatus for shutting down the source of noxious gases is a relay in some forms of the invention and that relay may be normally closed in some embodiments.

## Claims

### Claim 1

Apparatus for preventing injury from a noxious gas which comprises:
a shut off circuit for interrupting a source of electricity to an electrical appliance and interrupting a source of gas to a gas appliance;
a controller for controlling said shut off circuit, said controller having first and second states;
a sensor for sensing the presence of a noxious gas, said sensor being coupled to said controller to cause a change from said first state to said second state therein when the presence of a noxious gas exists, said change to said second state therein causing said shut off circuit to interrupt the source of electricity and the source of gas.

### Claim 2 (depends on 1)

The apparatus as described in claim 1 further including:
a latch for placing said controller in said second state.

### Claim 3 (depends on 2)

The apparatus as described in claim 2 further including:
a switch for overriding said latch.

### Claim 4 (depends on 3)

The apparatus as described in claim 3 wherein:
said switch is a manually operated push button.

### Claim 5 (depends on 4)

The apparatus as described in claim 4 wherein:
said controller is a relay.

### Claim 6 (depends on 5)

The apparatus as described in claim 5 wherein:
said shut off circuit is a relay.

### Claim 7 (depends on 6)

The apparatus as described in claim 6 wherein:
said shut off circuit is a relay that is normally closed.

### Claim 8 (depends on 7)

The apparatus as described in claim 7 wherein:
said controller is a relay that is normally open.

### Claim 9 (depends on 8)

The apparatus as described in claim 8 wherein:
said relay that is a part of said controller includes a holding coil and said switch interrupts electrical power to the holding coil of the relay that is in said controller.

### Claim 10 (depends on 9)

The apparatus as described in claim 9 further including:
a keypad coupled to said relay in said controller, said keypad being selectively able to prevent change of state of said controller from said first state to said second state.

### Claim 11 (depends on 1)

The apparatus of claim 1 further comprising:
a keypad coupled to said controller, said keypad being selectively able to prevent change of state of said controller from said first state to said second state.

### Claim 12

Apparatus for preventing injury from a noxious gas which comprises:
a shut off circuit for interrupting a source of electricity to an electrical appliance that is the source of the noxious gas and a source of gas to a gas appliance that is the source of the noxious gas;
a controller for controlling sad shut off circuit, said controller having first and second states;
a sensor for sensing the presence of a noxious gas, said sensor being coupled to said controller to cause a change from said first state to said second state therein when the presence of a noxious gas exists, said change to said second state therein causing said shut off circuit to interrupt the source of electricity and the source of gas.