US 5,427,136 A · Fluid level detection system

Abstract

A liquid level detecting device having an overflow reservoir, a flow restriction means and a level detecting means. The reservoir defines a cavity for collecting an electrically-conductive liquid overflowing from a container. This reservoir, which has a low level position associated therewith, includes inlet means through which the overflowing liquid enters, outlet means through which the collected liquid exits, and vent means through which built-up gases escape. Flow restriction means controls the rate at which the collected liquid exits through the reservoir's outlet means. Flow restriction means is calibrated such that the rate at which liquid exits the reservoir does not exceed the rate at which liquid overflows therein. In one embodiment, level detecting means includes a capacitive sensor switch which is fixedly secured to the reservoir to detect whether the liquid level is below the reservoir's low level position. In another embodiment, level detecting means includes a positive and a negative electrical probe attached to, and/or associated with, the reservoir. The positive and negative probes are electrically insulated from one another, in electrical communication with the reservoir's cavity, and positioned to detect whether the liquid level is below the reservoir's low liquid level position. In still another embodiment, an electrical probe is arranged to be in contact with ink overflowing from a second reservoir. This overflow condition is indicative that a normal flow of ink exists within the system.

Claims23

Dependent claims

A device for monitoring whether an electrically-conductive liquid within a container has fallen below a container's predetermined full level position of said container, said device comprises:

(a) overflow collection reservoir defining a cavity for collecting liquid overflowing from said container, said overflow collection reservoir having a predetermined low level position, and said overflow collection reservoir comprises:
(i) inlet means through which said overflowing liquid enters said overflow collection reservoir cavity,
(ii) first outlet means through which said collected liquid exits from said overflow collection reservoir, said first outlet means being positioned below said overflow collection reservoir's predetermined low level position,
(iii) second outlet means through which said collected liquid exits from said overflow collection reservoir, said second outlet means being positioned at said overflow collection reservoir's predetermined low level position, and
(iv) vent means for permitting escape of gases from said overflow collection reservoir;
(b) flow restriction means in fluid communication with said overflow collection reservoir first outlet means, said flow restriction means selectably partially restricting the flow of said liquid therethrough;
(c) second reservoir in fluid communication with said overflow collection reservoir, wherein the fluid communication between the overflow collection reservoir and the second reservoir is such that,
(i) when the liquid level in the overflow collection reservoir is below its predetermined low level positioned, liquid will not flow from the overflow collection reservoir to the second reservoir, and
(ii) when the liquid level in the overflow collection reservoir is at least at its predetermined low level position, liquid will flow from the overflow collection reservoir to the second reservoir, and
(d) level detecting means for detecting when the level of said liquid is below said reservoir's low level position, said level detecting means comprises a probe which extends downwards into the second reservoir, and said probe being designed such that an electrically conducting path will exist between it and the liquid flowing into the second reservoir from the overflow collection reservoir when the liquid level in the second reservoir is such that the liquid physically contacts the probe.

7 more elements

An apparatus for maintaining a predetermined full level of a liquid in a container from which liquid continuously passes, comprising:

(a) a main reservoir for the liquid;
(b) means for feeding liquid into the container from the main reservoir at a rate such that the liquid being fed therein overflows from the container through an overflow outlet at a position corresponding to the desired level of liquid in the container;
(c) an overflow collection reservoir designed to receive and collect at least part of the liquid flowing from the overflow outlet, said overflow collection reservoir having at least a first outlet through which liquid flows therefrom to the main reservoir, and a predetermined full liquid level, wherein said first outlet being positioned below said predetermined full liquid level;
(d) means for detecting when the liquid received and collected in the overflow collection reservoir is below the overflow collection reservoir's predetermined full liquid level;
(e) means for generating a signal when said detecting means detects that the liquid received and collected in the overflow collection reservoir is below the overflow collection reservoir's predetermine level;
and
(f) a vertically-oriented containing wall in fluid communication with said overflow collection reservoir, wherein said containing wall is designed such that, when the liquid received and collected in the overflow collection reservoir is not below the overflow collection reservoir's predetermined full level, liquid flows from the overflow collection reservoir into the containing wall.

4 more elements

Dependencies are inferred from the claim text.

Fluid level detection system

Life of this patent

Fluid level detection system

Life of this patent

Abstract

Claims23