LEAKAGE INDICATOR FOR A FIRE EXTINGUISHER

• US 3,735,376 A
• Filed: 03/05/1971
• Issued: 05/22/1973
• Est. Priority Date: 03/05/1971
• Status: Expired due to Term

• Current Assignee: Abdul N. Sitabkhan, Jack M. Kermer
• Original Assignee: Abdul N. Sitabkhan, Jack M. Kermer
• Inventors: Sitabkhan, Abdul N., Kermer, Jack M.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Partridge, Scott F.
• Application Number:
  US05/121,452
• Time in Patent Office: 809 Days
• Field of Search: 200/81,83 340/240,242 169/23,28 116/70
• US Class Current: 340/605
• CPC Class Codes: A62C 37/50 Testing or indicating devices for determining the state of readiness of the equipment

Abstract

A temperature compensated alarm mechanism for a fire extinguisher suitable for use on aircraft or other vehicles for determining whether the pressure of the fire extinguishing fluids within the main container has dropped below a predetermined value due to leakage or to other conditions. The mechanism includes, in addition to the main container, a miniaturized container which may be inserted into the main container and is filled with like fluids and arranged so that a diaphragm effectively separates the fluids of the two containers from each other. The diaphragm may be actuated in response to a predetermined droppage of the pressure of the main container to produce a signal indicating that the fire extinguisher may have been rendered incapable of responding with sufficient force to a condition requiring prompt attention for extinguishing or suppressing a fire. The mechanism is substantially non-responsive to wide variations in the temperature of the media external to the fire extinguisher.

Claims

1. The combination of a fire extinguisher having a first container filled with fire extinguishing fluid, a second container filled with fluid of substantially the same composition and proportion of fire extinguishing fluid as in the first container, a protective housing having a diaphragm for coupling the two containers to each other, said diaphragm sealing the second container so that one side of the diaphragm is subjected to the pressure of the fluid of the second container, the other side of said diaphragm being exposed to the pressure of the fluid of the first container, and means responsive to a predetermined differential pressure between the fluids of the two containers to render a signal substantially independently of the ambient temperature.

2. The combination recited in claim 1 in which the diaphragm is made of flexible material and the fluid is freon and nitrogen.

3. The combination recited in claim 1 in which the diaphragm is made of corrugated stainless steel.

4. The combination recited in claim 1 including a signal circuit responsive to the rendered signal.

5. A temperature compensated detecting apparatus for a fire extinguisher having a container filled with fire extinguishing fluid, comprising a second container mounted within the first container and filled with substantially the same fire extinguishing fluid as the first container, a flexible diaphragm for sealing the second container, one side of the diaphragm being exposed to the fluid in the second container, said diaphragm preventing the flow of fluid from either container to the other, the other side of said diaphragm being exposed to the fluid in the first container, and apparatus responsive to the flexure of said diaphragm by a predetermined amount to produce a signal independently of the ambient temperature.

6. A temperature compensating detector apparatus for a fire extinguisher according to claim 5, in which the diaphragm between the two containers is made of corrugated stainless steel so as to be flexible and continuously responsive to changes in fluid pressure.

7. Apparatus for a fire extinguisher for detecting leakage of freon and nitrogen from a container of the fire extinguisher, comprising means for responding to a droppage in the pressure of the freon and nitrogen of said container and non-responsive to variations in the temperature of external ambient conditions, said means including a second container filled with substantially the same proportion of freon and nitrogen and positioned closely adjacent to the first container and sealed by a flexible diaphragm so that one side of said diaphragm is exposed only to the fluid of the first container and the other side of said diaphragm is exposed only to the fluid of the second container, and a signalling circuit responding to the flexure of said diaphragm to indicate that the pressure on the side of said diaphragm exposed to the fluid of the first container has substantially departed from a predetermined level.

8. Apparatus according to claim 7 in which the diaphragm is composed of corrugated stainless steel and responds promptly to pressure variations.

9. Apparatus according to claim 7 in which the signalling circuit includes a switch which is mechanically coupled to the diaphragm.

10. Apparatus for detecting leakage of freon liquid and nitrogen gas from a fire extinguisher container independently of ambient conditions, comprising a miniature container filled with the same proportion of freon liquid and nitrogen gas, a housing sealed to the fire extinguisher container and coupling the two containers to each other so that the miniature container is cantilevered from the interior of the fire extinguisher container, the housing including a diaphragm one side of which hermetically seals the miniature container, the housing including an opening so arranged that the other side of the diaphragm receives and is exposed to the fluid in the fire extinguisher container, a switch member mechanically coupled to a central portion of the surface of said diaphragm, said signalling means controlled by said switch.

11. Apparatus according to claim 10 in which the signalling means includes a remotely controlled indicator.

12. A temperature compensated detecting apparatus for a fire extinguisher having a first container filled with fire extinguishing freon liquid and nitrogen gas comprising:

a mounting plate adapted to be mounted in the first container;

a second container mounted within the mounting plate and cantilevered into the interior of the first container and filled with the same fire extinguishing proportion of freon liquid and nitrogen gas as the first container;

a flexible corrugated, steel diaphragm for sealing the second container, one side of the diaphragm being exposed to the liquid and gas in the second container, said diaphragm preventing the flow of liquid or gas from either container to the other, the other side of said diaphragm being exposed to the liquid and gas in the first container, and means responsive to the flexure of said diaphragm by a predetermined amount for producing a signal independently of the ambient temperature between a temperature range of -65* F and +300* F.

13. Apparatus according to claim 12 including a switch positioned adjacent the diaphragm and responding continually to the deflection of the diaphragm, and a circuit controlled by the switch to generate the signal.