Water leak and water level detector

• US 5,058,421 A
• Filed: 06/08/1990
• Issued: 10/22/1991
• Est. Priority Date: 06/08/1990
• Status: Expired due to Term

• Current Assignee: NEC Electronics Incorporated (NEC Corporation)
• Original Assignee: NEC Electronics Incorporated (NEC Corporation)
• Inventors: Alexander, David V., March, Marvin, Toy, Stephen W.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): ROSKOS, JOSEPH
• Application Number:
  US07/535,072
• Time in Patent Office: 501 Days
• Field of Search: 73/49.2, 73/290 R, 73/304 R, 340/620, 340/618
• US Class Current: 73/49.2
• CPC Class Codes: G01F 23/241 for discrete levels
• CPC Class Codes: G01F 23/243 Schematic arrangements of probes combined with measuring circuits
• CPC Class Codes: G01M 3/16 using electric detection means G01M3/045, G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence

Abstract

A leak and liquid level detector includes a transistor as its main operating element with a pair of normally open base contacts connected to the transistor base. The transistor emitter is connected to ground and the transistor collector is connected to a suitable audio alarm, or alarm light or to a programmable logic controller. When a liquid leak bridges over the base contacts, a power circuit is closed across the contacts biasing the transistor and causing an electrical signal to flow from the collector to actuate the alarm, light or controller. The base contacts are linearly adjustable to sense various leak heights. The detector in one mode of use can be positioned horizontally to detect leaks and in a second mode of use is positioned vertically to detect a change in a liquid level in a tank, pipe column or the like.

Claims

1. A combined water leak and water level detector comprising:

an electrically insulating housing;

a transistor having a base, a collector and a ground-connected emitter, positioned in said housing;

a pair of base contacts connectible in series to said base, end portions of each of said base contacts being in spaced juxtaposition to each other;

a power source connected to one of said base contacts;

access means in said housing for permitting a predetermined level of conductive liquid to bridge across said end portions to form a resistive contact between said base contact end portions and a resultant forward bias of said transistor;

means connected to said collector and being actuatable by said resistive contact for indicating said liquid level; and

in which said base contacts are adjustable in length such that they can detect various depth levels of a liquid leak.

2. A combined water leak and water level detector comprising:

an electrically insulating housing;

a transistor having a base, a collector and a ground-connected emitter, positioned in said housing;

a pair of base contacts connectible in series to said base, end portions of each of said base contacts being in spaced juxtaposition to each other;

a power source connected to one of said base contacts;

access means in said housing for permitting a predetermined level of conductive liquid to bridge across said end portions to form a resistive contact between said base contact end portions and a resultant forward bias of said transistor;

means connected to said collector and being actuatable by said resistive contact for indicating said liquid level; and

wherein said housing is an essentially flat two-part container housing, said housing comprising a container base and a container cover, said transistor being mounted on said container base and being covered by said container cover, and wherein said base contacts extend from said base contacts transversely through said container base into an exterior-facing groove in a bottom surface of said container base.

3. The detector of claim 2 wherein said container is horizontally positioned on a horizontal mounting surface and said detector detects any leak fluid on said surface which bridges across said base contact end portions.

4. The detector of claim 2 wherein said container is vertically positioned on a vertical mounting surface and said detector detects a liquid level as said level raises to bridge across said end portions or drops to cease bridging across said end portions.