CZ20031889A3 - Device for remote detection of amount of water, aqueous solutions and urine in baby panties and swaddling clothes - Google Patents

Abstract

In the present invention, there is disclosed a device comprising an oscillation circuit (1) being provided with at least one capacitor and at least one inductor located inside a swaddle (4) or on the surface thereof. The device further comprises a radiofrequency tracer, disposed outside the swaddle to be monitored, consisting of a transmitter of a swept excitation signal and a receiver of a residual signal from the oscillation circuit (1), and intended for measuring changes in at least one parameter of the oscillation circuit frequency tracer. The tracer is provided with acoustic or light signaling device. The oscillation circuit (1) employed is preferably formed by a flat spiral. Said oscillation circuit (1) or some component thereof can be provided with a layer of hydrophobic material (2), preferably polyethylene or polypropylene, or it can be provided with a layer of hydrogel. Preferred is the use of a membrane (5) consisting of a hydrophobic layer (5a) and a layer of hydrogel (5b), based for example on poly(hydroxymethyl methacrylate) or sodium polyacrylate. The oscillation circuit (1) can be attached to a collecting layer for supply of water, aqueous solutions or urine from other portions of the swaddle.

Description

Device for remote detection of water, aqueous solutions and urine in diapers and diapers

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a device for the remote detection of moisture in diapers, diapers, or sanitary napkins, briefs which do not require the use of signal wires.

State of the art

The automatic monitoring of moisture (ie the amount of water, aqueous solutions or urine) in diapers allows you to prevent sore spots in children by repackaging them before they can register and report their discomfort. Mothers or babysitters do not have to regularly check their diapers by unpacking and disturb the baby, for example in their sleep. Such a device also helps to eliminate older children from urinating at night with an acoustic alarm. Likewise, it is advantageous to automatically monitor moisture in diapers, sanitary napkins, briefs, etc. for adults, for example in medical facilities.

Previously manufactured devices (eg DRI Sleeper, Nytone, Train Threads, Wetstop) consist of a multi-use conductivity detector that is connected to the control electronics by a conductor. Various disposable conductive detector arrangements or directly integrated diaper detectors are described in many patents, e.g., US6200250, US6097297, WO9963497, US5838240, JP11033055. Further, changes in transparency (JP11178855), changes in cell electromotive force (JP5180800), dissolution of a mechanical contact blocking particle (JP2001289775), or changes in capacitance of a flat electrode capacitor (CN1213529) can be used to detect diaper moisture.

The main drawbacks of the wiring solution are: i) not quite easy handling of the equipment that is very commonly used, and ii) the entanglement of the child in the wire.

Remote humidity transmission (without interconnecting wires) is most often handled by a small walkie-talkie that is connected to the diaper detector (eg US2002026164). In the patent

JP2001161732 discloses a transmission by remote monitoring of a change in the resonant frequency of an oscillating LC circuit that is affected by pressure-sensitive adhesive tapes. Similarly, it is

JP2002224151A2 discloses a complex moisture-indicating LC circuit placed on the diaper surface.

A universal detector and method for the remote determination of chemical materials, pH and temperature using a resonant circuit is described in US6359444. The resonant circuit is applied to a suitable structural unit of selectively sensitive material that causes the resonant frequency of the circuit to change. It is remotely measured by a radio frequency follower.

Placing the detector in the diaper affects its properties. Some diapers already contain suitable placement parts. Such is the distribution layer described in the patent CZ 284792. The diaper diaphragm remote sensing method described below utilizes the characteristics of an oscillating LC circuit whose frequency response is affected by the amount of water or urine present.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The present invention provides a device for the remote detection of the amount of water, aqueous solutions or urine (hereafter "absorbate") in diapers and diapers, or other sanitary needs, comprising an oscillating circuit (containing capacitor and inductor) located inside or on the diaper a surface and a radio frequency tracker that measures changes in one or more of the oscillating circuit frequency response parameters. Frequency response is influenced by the amount of absorbate in the diaper. This oscillating circuit, without containing selectively absorbent-sensitive material, is a suitable diaper detector since there is no change in state other than an increase in the amount of water, aqueous solutions or power present. An oscillating circuit consisting of a parallel-connected flat spiral coil and a capacitor appears to be most suitable for this purpose and is located at a suitable location in the diaper. The penetration of the absorbate near the detector changes the frequency response of the oscillating circuit by one or a combination of the following factors:

1. The (electrical) permittivity of the environment around the flat coil changes, thereby adding parasitic capacitance to the circuit.

2. Change the conductivity of the surrounding environment, adding parasitic resistance to the circuit.

The resonant frequency and / or the quality of the oscillating circuit will change in the frequency response.

The oscillating circuit may be wrapped with a hydrophobic layer which, by its thickness, regulates the sensitivity of the detector and prevents the penetration of liquids to the oscillating circuit and eventual elution of soluble components or contaminants into the diaper. In this case, only the factor 1 affects the frequency response of the oscillating circuit.

Advantageously, the properties of the aforementioned moisture detector can be modified by a membrane which encapsulates or adjoins the oscillating circuit or a portion thereof (e.g. a flat coil). The membrane is composed of a hydrophobic layer and a hydrogel layer. Hydrogel absorbs absorbate and swells. In addition to factor 1, the following factor also affects the frequency response:

3. Dimensional changes of the swelling hydrogel foil simultaneously cause dimensional changes of the coil and thus its inductance.

The induced changes in capacitance and inductance cause a change in the resonant frequency of the oscillating circuit.

The oscillating circuit optionally encased by the membrane may be attached to the collection layer in the diaper. The collecting layer and possibly the membrane influence the detection range and the response speed of the detector. This makes it possible to optimize the use of diapers.

The frequency response of the oscillating circuit, or any of its parameters, is remotely measured by a radio frequency monitor, to which an evaluation apparatus may be connected acoustically or optically to indicate the amount of absorbate present in the diapers, or exceed the specified limit.

For the production of the detector and the related tracer, it is possible to use the already established technology of electronic goods protection in shops. This makes manufacturing and insertion of the detector into diapers very cheap and makes it disposable.

Overview of the drawings!

In FIG. an oscillating circuit provided with a hydrophobic layer is shown

Fig. 2 shows an oscillating circuit encased in a membrane consisting of a hydrophobic layer and a hydrogel layer

Figure 3 shows the location of the oscillating circuit on the diaper

The advantages of this method of remote humidity detection in diapers are illustrated in the following examples.

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DETAILED DESCRIPTION OF THE INVENTION

Example 1

The oscillating circuit I, consisting of a parallel connected spiral coil and a capacitor, is located in the absorbent body 3 of the diaper 4. The penetration of an aqueous solution or urine near the detector changes the frequency response of the oscillating circuit 1.

The cost of producing such a detector is very low. It can therefore also be used in disposable diapers.

Example 2

The oscillating circuit 1, positioned as in Example 1, is wrapped with a hydrophobic layer 2 (for example polyethylene, polypropylene), which, by its thickness, controls the sensitivity of the detector and prevents the penetration of liquids to the oscillating circuit 1 and eventual washing of soluble components or contaminants into the diaper 4.

Example 3

The membrane 5, which envelops the oscillating circuit 1, consists of a hydrophobic layer 5a (adjacent to the detector) and a hydrogel layer 5b which is a crosslinked softened poly (hydroxyethyl methacrylate). The hydrogel shell 5b has a lower affinity for absorbate than the absorbent present in the diaper. Until the absorbent capacity of the diaper 4 is consumed, the absorbent penetrates to the oscillating circuit 1 to a limited extent. However, the additional amount of absorbate added already reaches the oscillating circuit 1 closer and changes its frequency response.

In this way, it is possible to optimize the utilization of the absorbent capacity of the diaper 4.

Example 4

The membrane 5 of Example 3 consists of a hydrophobic layer 5a (adjacent to the detector) and a hydrogel layer 5b which is a cross-linked sodium polyacrylate. This material is used as a so-called superabsorbent in the absorbent body of diapers, making its approval for use easier. In addition, the detector thus modified also has its own capacity in the total absorbent capacity of the diaper 4.

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Example 5

The oscillating circuit I (or the diaphragm-coated oscillating circuit) is attached to a collection layer that is able to deliver absorbent from other parts of the diaper to the detector. This layer is made of a nonwoven hydrophilic fabric and may pass through the absorbent body 3, may be embedded in the diaper 4 on the side closer to or farther from the body. Advantageously, the so-called partition layer can be used. Thus, it is possible to detect both the saturation of the diaper in the urine and contamination by solid excrement.

Industrial applicability of the invention

The detector according to the invention can be used in the manufacture of disposable diapers or diapers, or in the production of other types of hygiene articles.

Claims (10)

A device for the remote detection of the amount of water, aqueous solutions and urine in diapers and diapers or hygiene articles, characterized in that it consists of an oscillating circuit (1) with at least one capacitor and at least one inductor disposable inside the diaper or on a surface thereof and a radio frequency follower for measuring changes in at least one frequency response parameter, wherein the follower is provided with an acoustic or light signaling device. Device according to claim 1, characterized in that the oscillating circuit (1) consists of one capacitor and one inductor. Device according to claim 1 and 2, characterized in that the inductor is a flat spiral Device according to claims 1 to 3, characterized in that at least one component of the oscillating circuit (1) is provided with a layer of a hydrophobic material (2), preferably polyethylene or polypropylene. Device according to claims 1 to 3, characterized in that at least one component of the oscillating circuit is provided with a hydrogel layer. Device according to claims 1 to 3, characterized in that at least one component of the oscillating circuit is provided with a membrane (5) composed of a hydrophobic layer (5a) and a layer of hydrogel (5b). Device according to claims 5 and 6, characterized in that the hydrogel is based on poly (hydroxyethyl methacrylate). Device according to claims 5 and 6, characterized in that the hydrogel is based on sodium polyacrylate. Apparatus according to claims 5 to 8, characterized in that the hydrogel comprises particles of ferromagnetic material. · «4 4 4 4 4 4 4 4 © 4 4 100 9 * · o ··· 9 9 9 9 9 9 · · 9 9 9 9 9 99 9 9 9 9 9 9 9 9 9 9 9 9t 99 Apparatus according to claims 1 to 9, characterized in that the oscillating circuit (1) is attached to the collecting layer for supplying water, aqueous solutions and urine from other parts of the diaper (4).