Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
  • G08C19/00—Electric signal transmission systems

Definitions

• the object of the invention is an arrangement for the detection of changes in ambient and states of ambient, for example detecting factors of interest, such as moisture in the structures of buildings and in diapers of infants and chronics. Other applications involve temperatures above or below allowed limits, movement in structures due to e.g. fatigue of materials, etc.
• Moisture damage to buildings has been found to be quite common. Moisture damages occur in as many as 55% to 90% of residential buildings. Visible mould fungus is found in approximately one third of the houses built after 1950. Mould fungus spores have been found to be highly allergenic. Various studies have estimated that as many as 50% of asthmatic persons are allergic to moulds. Mould spores also increase the susceptibility of exposed persons to catch respiratory diseases caused by viruses and bacteria.
• Patients who have very sensitive skin, are those suffering from e.g. infection caused by bacteria or virus, diabetes, allergy, suppressed immunity or poor blood circulation.
• skin of a baby may irritate in such a way that a change of a diaper must be done immediately after urination or defecation.
• Bed-wetting patients form a distinct group, which is treated successfully with moisture alarm system, which wake up a patient as soon as a bed-wetting takes place.
• the method is the better the more sensitive it is. In other words an alarm is needed immediately after beginning of urination.
• the reference FI 100138 does not include any means to affect on the sensitivity and/or selectivity of the transducer means. Under the circumstances by using the known technique one cannot offer a satisfactory solution for the problem situations mentioned above.
• the arrangement according to this invention enables the detection of changes in ambient conditions in a versatile manner, and the solving of problems similar to those described above.
• Fig. 1 shows an arrangement according to the invention, with a transducer device and a detection unit
• FIG. 3 shows the connection of a possible embodiment of the detection unit
• FIG. 4 shows the operating sequence of the detection unit and the detection signals in two different cases
• FIG. 5 shows the use of an arrangement according to the invention in monitoring moisture in a diaper or in a bed of a person, such as a patient or a baby, in such a way that the detection device is connected to a central monitoring room.
• - Fig. 6 shows a transducer device including a circuit L and C on a substrate B, whose properties affect the properties, such as sensitivity for certain changes in ambience, of the transducer device.
• - Fig 7. shows a transducer device, which includes components L, C and B and particular components SW (Sensing Wires), which are realised in such a way that the changes in ambience affecting them affect also properties of the transducer device.
• Fig. 8 shows two transducer devices which have a specific intermediate layer SL (Sensing Layer), which affects on the properties of the transducer device and which is . affected by properties of the object under study OUS (Object Under Study), the properties of SL can be dependent on time, place or on other variable or a combination of those, in the transducer devices in the figure the other include a spatially esstentially homogenous SL and the other include SL which has properties which are spatially dependent.
• SL Signal Layer
• - Fig. 9 shows a transducer device, which has in addition to a layer SL another layer FILL, whose properties affect for their part on the properties of the transducer device.
• Fig. 10 shows a transducer device, which includes as an example three circuits C1 , L1 , and C2, L2, in the example case of the figure these circuits are connected with a cable
• a transducer device which includes as an example three circuits, in this case resonance circuits, the first circuit L1 , C1 on a substrate B1 ,
• the second circuit L2, C2, on a substrate B2 and the third circuit L3, C3, on a substrate B3, circuit L1 and L2 are coupled together electrically, for example via mutual inductance M12, and circuits L1 and L3 are coupled together electrically, for example via mutual inductance M13.
• Fig 12 shows as an embodiment of the invention a diaper SN (Sanitary Napkin), which includes a detection device TC1 for monitoring of accumulation of moisture and a detection device TC2 for detecting faeces.
• Fig. 1 shows the main parts of an arrangement according to the reference F1 100138:
• TC Transducer Circuit
• TC Transducer Circuit
• Detection Unit is a detection unit, which may be hand-held, containing, associated with the operation, an operating control OC (Operation Control), which can be e.g. a push-button, and further containing indication devices, for example SI (Sound Indicator) is a sound indicator and VSI (ViSual Indicator) a visual indicator device such as a signal light (lamp, light-emitting diode, liquid crystal display, or the like.).
• SI Sound Indicator
• VSI Visual Indicator
• the detection unit can be connected through wires or wirelessly to a central unit in a control room, or through a telephone device to wireless pagers, a radio telephone apparatus (e.g. GSM, NMT), etc.
• TC is in an electrical coupling between surroundings to be observed.
• an electrical coupling is conductive, or capacitive or inductive coupling or coupling via electromagnetic radiation or coupling via any combination of the said couplings and furthermore a conductive coupling may mean either metallic (via electrons) or electrolytic (via ions) coupling.
• Fig. 2 shows some embodiments of transducer TC.
• TC can contain a resonance circuit consisting of a coil L and a capacitor C.
• the components L and C can be implemented e.g. with the same technology as transducer components in modern burglar alarms.
• Such solutions and also solutions associated with the implementation of detection units are shown e.g. in reference US 5,381 ,137. These solutions can be applied in arrangements according to the present invention.
• TC may be realised also by using printed circuit technology, which is commonly used in electronics devices. In this way one may produce different shapes and sizes at low costs without significant tooling costs.
• TC may be even a printed circuit board with multiple layers and the circuits of TC may be realised on different layers.
• a transducer circuit may have one or more sensing elements SE.
• SE is a thin metal foil, which short-circuits several turns of coil L. If foil SE breaks or is gradually displaced due to e.g. an electrochemical process, the inductance of L increases and the resonance frequency of the circuit decreases.
• SE is placed in one of the two electrodes of a capacitor; in this case a breaking of SE or a displacement of SE due to an electrochemical process causes a reduction of capacitance C and an increase in the resonance frequency. SE may also break the transducer-circuit coil L. Then there will naturally be no resonance frequency of the circuit.
• EDC Excitation/Detection Coil
• EA Excitation Amplifier
• This oscillation induces in EDC a signal, which is connected through capacitor C to preamplifier PA and band-pass amplifier BPA. After BPA, there is a peak detector, which during the pulse is reset under the control of the GATE signal. A comparator COMP detects the oscillation. If the amplified signal exceeds the reference level VREF, a detection signal DTS is transmitted.
• DU can identify TC through it's specific frequency or DU may include means for calculation of frequency spectrum of a signal emitted by TC for example via Fourier transformation or by using some other spectrum analysing method such as autoregressive algorithms or wavelet transformations.
• DU may also include memory means to store a received signal and/or some information derived from a signal.
• means in DU for storing also an identification of the detection site for example in a wireless manner by using e.g. TIRIS equipment manufactured by Texas Instruments (USA) or by using some other wired or wireless technique.
• Figs. 4a and 4b show, with reference to Fig. 3, an operation sequence (detection sequence).
• a current pulse is sent to coil EDC. This pulse is shown on the ICOIL axis.
• the generated signal is shown on the SIGNAL axis, and the signal detection time after the pulse is DTIME.
• the operation is illustrated by an example where TC is placed for example in a diaper. When the diaper is dry, TC oscillates for a long time at its specific frequency, because the quality factor (Q-factor) of the circuit is good. Thus during the detection time DTIME a strong signal is detected.
• DU can without effort be used to check whether a need exists for changing the diaper.
• DU may operate also in such a way that the frequency of the oscillator of DU is to be sweeped over that frequency range which includes the resonance frequencies of the circuits of TC.
• DU detects the loading of the detection coil and when the resonance circuits of TC are coupled to the coil, one detects a corresponding change, which has characteristics, which may be used for measuring for example variables related to the Q-values of the resonance circuits of TC.
• TC may include also one or several elements, which have a strong electric nonlinearity, in this case a signal generated by TC from excitation of DU includes harmonics of the fundamental frequency and the circuits of DU are realised in such a way that they are capable to detect at least partially said harmonic frequencies.
• non-linear components can be semiconductor junctions, capacitors, whose dielectric constant of dielectric is dependent on voltage or inductances having a core with permeability dependent on density of magnetic flux.
• nonlinearity must be rather strong at those levels of voltage and current, at which TC is operating in that application.
• Fig. 5 shows schematically an arrangement according to the reference FI 100138, where DU is attached for example to a bed or a pram PB (Patient Bed), the DU energy exchange means EDC, which can be a conductor loop, can be placed under or inside the mattress MT to improve sensitivity.
• EDC which can be a conductor loop
• TC which is not shown in the Figure, is located in a place such as a diaper or clothes of a person P lying on the bed.
• DU is connected through signal transmission STM (Signal Transfer Mean) to a central observation unit COU (Central Observation Unit).
• STM may include a wired or wireless connection.
• STM may include a telephone, radio, ultrasound, light (infrared), or other conceivable communications devices.
• COU can be in contact with many DUs.
• each DU for transmitting identification information to allow COU to identify the DU transmitting the information.
• COU may also contain means for monitoring and controlling other quantities. Such quantities may be blood pressure, ECG or movements of P detected by means (e.g. piezoelectric material) provided in mattress MT to convert movements into electric signals.
• the central observation unit COU is an entity generally associated with observation. It may therefore comprise separate display devices, central units and their controls.
• the central observation unit COU may consist of many hierarchic units, which form a larger network. Such a network can give the first alarm for example in a local unit, which e.g.
• a tape-formed TC with an adhesive surface can be used.
• Such adhesive tape TC can be fastened to structural locations where moisture damage is probable, e.g. under the bathroom floor, besides the piping for underfloor heating, and in kitchen structures.
• the SE element which by an electrochemical process alters some characteristic of TC, e.g., the resonance frequency or the Q-factor. Then TC reacts permanently to long-term exposure to moisture only.
• the choice of the types and quantities of metals in the SE can regulate sensitivity.
• the response of TC to short-duration exposure to moisture by e.g. a reduction in the Q-factor of its resonance circuit.
• FIG. 6 shows a transducer device of the invention, in which a coil L and capacitor C is placed on a substrate B (Base), which is designed so that a for ambient changes sensitive part of a wiring of L is designed so that it may be placed on a desired place.
• the wires SW (Sensing Wires) of the transducer device according to the figure are connected to the coil L in such a way that the Q value of the resonance circuit formed by L and C is modified by resistance between the wires which is modified e.g. by moisture.
• a transducer device like this may be used in a following way:
• the resonance circuit formed by the coil L and the capacitor C is placed near a surface where a detection using a detection unit DU (Detection Unit) can be made.
• DU Detection Unit
• the sensitivity of SW can be made dependent on location so that SW is covered with insulating material such as lacquer, and a sensitive part is at least partially left without covering or is covered with material, which affects the coupling of SW with surroundings.
• insulating material such as lacquer
• material can be as an example water-soluble lacquer, which just after long-term effect of moisture is leaving from the sensitive part and enables the effect of a change in moisture to affect on the properties of TC via the sensitive part.
• the sensitive part of SW will be placed in a desired place in the structure to be studied. In this way the high sensitivity of the system is preserved also with objects, which one cannot approach with DU.
• Another application is a diaper of chronically ill patient, in which case a capacitive coupling to moisture absorbing material senses wetting of the diaper and SW is placed in an area where faeces decreases resistance and the transducer indicates a need for changing the diaper. This is because diapers have a good capability to absorb urine and keep skin of a patient dry, but due to fast irritation of skin by faeces a diaper must be changed immediately.
• a sensitive area of SW may be large compared to a cross-sectional area of a wire.
• a TC placed in a diaper is one construction of TC of the invention, in which a coupling may be mainly capacitive (in the example case that part of TC which detects wetting of a diaper) and galvanic (that part, which according top the example detects faeces).
• a corresponding construction may be used for solution of other problems such as in monitoring of moisture in buildings.
• TC may also be placed in means, which are provided for dressing of diaper on a person, such as nappy trousers or linen. In this case TC and the said means for dressing may be either disposable or non-disposable.
• TC may also be attached to a doormat, which is used in public buildings and an arrangement described monitors moisturising of a mat and notifies a condition of the mat to a responsible service company about excessive moistening of the mat.
• Figure 7 shows more precisely a placement of TC of the invention relative to an object under study OUS (Object Under Study).
• OUS Object Under Study
• SL may prevent effect of changes form known direction on some properties of TC. Because in some realisations of TC, in which a coil L is wire loops placed side by side on a plane and these loops are capacitively coupled to OUS, one may change this coupling by selecting SL with a proper thickness. The thicker SL the weaker is the coupling, and the less sensitive TC is on the changes, which takes place in OUS. Material of SL affects also on the strength of the coupling.
• TC is sensitive nearly completely in opposite direction relative to said static shield.
• TC may also be splitted in such a way that it includes two or more resonance circuits, from which each has been sensitised to one or more changes of OUS.
• TC includes some structures, which are not sensitive to changes in OUS. These structures may be used for location of TC in parts of a building and in such a way one may clarify for example some effects of moisture on other parts of TC.
• Figure 9 shows a solution, where a transducer device includes in addition to base B, circuits L, a layer SL and filling material FILL.
• filling material FILL for example a material, which absorbs strongly moisture and SL having permeability only for water vapour (such as Gore-Tex, Gore Inc., USA), TC will become a transducer device, which is suitable for long term monitoring of high relative moisture level.
• SL may be some other polymer, glass or metal material or a combination of these, which is chemically, through irradiation or mechanically modified to pass water vapour, but because of size of pores or of electric charges of sides of pores unable to pass liquid water or water attached to salt ions.
• circuit L is a pat of a resonance circuit
• TC may operate depending on the construction as on/off-type or as a gauge for the strength of exposure of moisture.
• the Q-value may be dependent on moisture and by measuring the Q-value one may measure moisture prevailing in an area of an object OUS.
• TC may be realised as follows: One part of TC will react for moisture and that part has a specific first resonance frequency (e.g. 8 MHz), another part of TC does not react for moisture and operates at a second resonance frequency, (e.g. 14 MHz).
• first resonance frequency e.g. 8 MHz
• second resonance frequency e.g. 14 MHz
• TC may be located by using the second resonance frequency (in this case 14 MHz) and moisture level may be detected using the first resonance frequency (in this case 8 MHz)
• the operation frequency of TC will be selected in such a way that it is applicable for the specific purpose as well as possible.
• the operating frequency should be larger than the above mentioned 8 and 14 MHz, in this case TC may be smaller and a coupling between TC and DU can be more easily realised.
• TC and DU some electrically conductive material, it may be beneficial to select significantly smaller operating frequency, e.g. 200 kHz. In this case the permeability of material is much better.
• DU may also include means to transfer some energy e.g.
• transducer means TC via electromagnetic fields to transducer means TC and this may be realised at different frequency (e.g. at 200 kHz) as the actual collection of information (e.g. at 8 MHz).
• One application where low frequency operation may be beneficial is monitoring of moisture of ground of building e.g. under crawling space.
• TC would be placed in surface layers of ground and by using DU inside building one can monitor, when moisture level of ground will be so high that a probability of mouldy damages will be high.
• FIG 11 shows a solution for realisation of TC in such a way that it includes the first electric circuit, in the figure as an example a resonance circuit, which includes a coil L1 , a capacitor C1 and substrate B1 , in addition TC includes a second and third electric circuits, which in figure are represented by resonance circuits L2, C2 on substrate B2 and L3, C3 on substrate B3.
• the second and third electric circuits are coupled via mutual inductances M12 and M13 to the first electric circuit.
• the coupling between circuits can be also conductive or capacitive or it may be a combination of the mentioned coupling modes.
• circuits are not limited to that mentioned above, but it is de- termined by the need. In the same way the circuits may be coupled to their surroundings in different ways and their realisations can deviate in other ways from each other. In some cases one of the circuits will act as some kind of antenna between DU and other circuits. This circuit can be larger than other circuits and can be placed closer the site where DU observes a state of the circuits.
• transducer TC1 for detection of moisture in a diaper is placed nearer the outer surface of the diaper SN and a transducer TC2 detecting faeces is placed closer the inner surface of the diaper SN.
• TC1 and TC2 may be essentially separate transducer elements but in some cases it may be beneficial to make TC1 larger than TC2 and make an arrangement where TC2 is detectable via TC1 due to mutual coupling between the circuits. In this case the detection distance for TC2 is longer than without using TC1.
• TC1 can also be separate (it is not placed in a diaper) and placed in diaper trousers or diaper linen. TC may be placed in objects, which are observed, during suitable production phases.
• So TC may be placed for example in an element of a ready-made house, such as a bathroom element or in a construction already during production. Such a building element or complex monitored with TC enables a production of high quality buildings and monitoring of end product without significant additional costs. In the same way TC can be inserted in diaper, foodstuff, package etc. already during a production phase.
• TC may also include an active circuit having various functions, such as memory circuit, in which one may store calibration information for TC, measurement results, measurement times or other information important for detection.
• the active circuit can also include functions for measurement or functions and means for signal transfer.
• the active circuit may include e.g. a signal transmitter.
• Said active circuit can include e.g. means for measurements of temperature or pressure.
• the active circuit may also take needed energy during a reading period from electromagnetic energy transmitted by DU or by some other energy source.
• TC may also include an energy source needed by the active circuit, such as a battery and it is also possible that said battery will be charged with energy transmitted by DU or said battery is formed from pairs of materials, which have different electrochemical potential and material connecting these will be electrolyte required by battery due to an effect of moisture.
• Applications for such TC include e.g. alarm for moisture damages, measurement of temperature of concrete and pressure measurement of a tyre.
• a transducer device TC may include detection means, on which known variable or variables to be observed such as temperature or humidity affect and whose characteristics will change due to this effect in such a way that a change may be detected from energy emitted by the transducer device.
• Said transducer device can be for example a capacitor, which is changing due to temperature or moisture. This kind of capacitors are available from many component manufacturers.
• the detection means may also include a material layer which is consistent or divided in parts and this layer includes material mixture such as wall filler (such as Vetonit 6000), which includes salt or salts having a known characteristics by moisture or polymer having combined with salt or salts. Suitable saltcompounds are used commonly as calibration salts in calibration of humidity transducers.
• a detection device may serve also a piece of wood, because it is known that conductance of wood is dependent on moisture.

Applications Claiming Priority (2)

Publications (2)

Family

ID=8562415

Family Applications (1)

Country Status (2)

Cited By (3)

Citations (6)

• 2001
  • 2001-12-05 FI FI20012393A patent/FI20012393A0/fi unknown
• 2002
  • 2002-12-05 WO PCT/FI2002/000998 patent/WO2003050490A2/en not_active Application Discontinuation

Patent Citations (6)

Also Published As

Similar Documents

Legal Events