Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-06-21
2004-01-13
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S605000, C340S572100, C340S573100, C340S627000, C340S552000, C340S568100
Reexamination Certificate
active
06677859
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for detecting a fluid; use thereof for detecting the level of fluid in a container; and use thereof for monitoring a leak of fluid from a body containing said fluid, in particular a leak of body fluid from a human or an animal.
The present invention further relates to a method and apparatus for detecting a temperature.
The present invention still further relates to a sensing device for sensing an external parameter, in particular a fluid or a temperature.
1. The Technical Field
Generally detection of a fluid, e.g. for detecting the level of a fluid in a container or for detecting a leak of fluid from a body such as a container or a human or animal body containing said fluid comprises production of a sensor signal of the fluid and detection of the produced sensor signal by appropriate detection electronics.
In applications of e.g. detecting levels or leaks of stationary oil containers, or detecting leak of body fluids from patients or elderly confined to a bed, the sensor of the fluid and the detection electronics are typically interconnected by electrically conducting connectors e.g. wires or cables. However, such connections can be sensitive to damage and for patients or elderly confined to a bed they can be very inconvenient and put severe constrains on their movability.
Particularly for patients or elderly who are able to walk around, such electrical connections cannot be used without restricting their movability.
Since lack of movability of patients and elderly requires an increased level of monitoring of e.g. wounds and urinary and faecal incontinence by personnel, such a monitoring often being considered inconvenient and cumbersome, electrical connections of monitoring devices implicitly contribute to bad sanitary conditions for patients and elderly and contaminated environments of wound healing sections, incontinence sections and the like of hospitals and nursery homes.
A similar situation holds for monitoring the temperature of patients and elderly.
Wireless connection based on suitable receiver/-transmitter electronics at the sensor and detection electronics can be contemplated. However, in order to function, such electronics requires a portable power supply such as a voltage battery. This is impractical because of the necessary exchange or recharge of discharged batteries.
Consequently there is a need for wireless connection of fluid sensor, or temperature sensor, respectively, and detection electronics which do not require portable power supply; as well as sensors suited for sensing exposure of an external parameter, in particular fluid or a temperature without requiring external power supply.
2. Prior Art Disclosures
International Application No. PCT/NL/00083 discloses an assembly for detecting and signalising wetness of a diaper; said assembly comprising an electronic device mounted in a housing to be applied on a diaper and directly connected to connectors on a sensor strip adhered to the inside or outside of said diaper for detecting presence of wetness near said conductors.
U.S. Pat. No. 4,646,066 discloses an indicator device and method of measuring incremental environmental exposure of an environmental parameter; said method comprising measuring responses of a target to an electromagnetic interrogation signal; said target. including a tuned circuit and an element that is sensitive to environmental exposure, especially exposure to specified fluids e.g. liquids and water vapour, influencing the electronic or ionic conductivity. There is no teaching of parameter influences including the capacitance of the tuned circuit, nor of a measuring method based on changes of transmission of electromagnetic energy of oscillators transmitting electromagnetic energy to the tuned circuits.
EP 0 715 152 discloses a sensing device for sensing the presence or absence of an article, e.g. a material, a liquid, a powder, and the human body; said device comprising an oscillator for generating a high frequency signal; a sensor including a resonance circuit for receiving the high frequency signal from the oscillator and a detector for producing a signal relating to a variation of an impedance change of the sensor; said sensor and detector being coupled through a cable.
GB 2 113 835 discloses a sensor for detecting quantities such as position, force, pressure, liquid level, flow, temperature, voltage, current, and magnetic field; said sensor comprising opto-electric means for converting optical energy into electric energy and vice versa and at least one electric resonant circuit and means arranged to influence a characteristic of the resonant circuit by the quantity to be detected.
U.S. Pat. No. 5,570,082 discloses a device for detecting wetness in diapers for the purpose of calling the attention of the caretaker. The device is a combination of an antenna, a non-linear element and two parallel electrodes, the two electrodes being enbedded in the diaper in an area likely to experience wetness and being adapted to provide a strong coupling between the antenna and the non-linear device when subjected to wetness thereby reducing the resistance between the electrodes. This device does not include a resonant circuit.
DISCLOSURE OF THE INVENTION
Object of the Invention
It is an object of the present invention to provide a method and apparatus for detecting a fluid without using an electrical connection between a sensor of the fluid and an electronic detection system therefore and without requiring a portable power supply for the fluid sensor.
It is another object of the present invention to provide a method and apparatus for detecting the level of a fluid in a container, in particular the level of a human body fluid collected in a container; or for detecting the level of an infusion liquid in a container, in particular the level of an infusion liquid in a plastic bag, e.g. of soft plastic that collapses during emptying thereof.
It is another object of the present invention to provide a method and apparatus for detecting a body fluid from a human or animal body, in particular a leak of body fluid from a human suffering from e.g. urinary and/or faecal incontinence, a human or animal undergoing surgery requiring a drain of body fluid, or a human or animal having e.g. a bleeding wound.
It is another object of the present invention to provide a method and apparatus for detecting a temperature.
It is another object of the present invention to provide sensors for such methods and apparatus
Further objects will be apparent from the description,
Solution According to the Invention
In an aspect, the present invention relates to a method and an apparatus for detection of a fluid, and use thereof.
“Method of Detecting a Fluid”
In an aspect according to the invention these objects are achieved by providing a method of detecting a fluid as claimed in claim
1
; said method comprising providing one or more oscillators transmitting electromagnetic energy; providing one or more resonant circuits receiving electromagnetic energy from the oscillators; bringing the fluid and the one or more resonant circuits into contact with each other so that the receptions of electromagnetic energy of the resonant circuits are changed; and detecting changes of the transmissions of electromagnetic energy of the oscillators by changes in one or more characteristics thereof upon the changes in the receptions of the electromagnetic energy of the resonant circuits, whereby receiver circuits for receiving and detecting responses of the resonant circuits can be avoided.
“Apparatus for Detecting a Fluid”
In another aspect according to the invention these object are further achieved by providing an apparatus as claimed claim
6
; said apparatus comprising one or more oscillators for transmitting electro-magnetic energy; one or more resonant circuits for receiving electromagnetic energy from said oscillators; and one or more detectors for detecting changes in one or more characteristics of the one or more oscillators upon changes in characteristics of
Bent Thorning Bensen A/S
Darby & Darby
Nguyen Tai T.
Wu Daniel J.
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