TEST PROBE FOR MEASUREMENT OF MOISTURE IN STRUCTURAL MATERIAL

Abstract: The invention relates to a test probe (1) primarily intended to be applied in structural material (2) during the production and/or building stage or when water damage has occured in a building and by which moisture measurement can be done undisturbed from outer factors in following the drying out process of built in moisture or other inconvenient, supplied moisture which can cause troubles in the form of mould and/or damages caused by putrefaction, as well as damages on floor coverings and other structural elements. The test probe (1) comprises an active part (3) of a hygroscopic material which is enclosed in an outer, mechanical cover (4), said cover has that property to allow passage of water steam, but prevents passage of water in liquid phase.

Description: Test probe for measurement of moisture in structural material. The present invention relates to a test probe which primar¬ ily is intended for being applied in structural materials during the moment of production and/or building activity or when a water damage has been occured in a building and by which test probe moisture measurement can be performed un¬ disturbed from outer factors in following of the drying up process of built in moisture or other not suitable, supplied moisture which can cause inconveniences in the form of mould and/or damages caused by putrefactions, as well as damages of floor coverings and other structural elements. At present the problem of building moisture within the building sector is a scourge which besides the fact that it causes many practical problems, e.g. origin of mould and other "sick house" problems, is the source of very wide and in itself unnecessary increases in prices. Today the idea of the used technique to reveal the departure of building moisture is that you drill a hole in the building element in question to a desired depth, where you want to determine the moisture level. A transmitter is then inserted into the hole, by aid of which you can read on an after-connected instrument the temperature and the relative humidity of the material (RF%) . Several types of transmitters are used and for all concern that the unexactness proportionately is as large as about ^3-5 % RF. The technique of this measuring method is relatively complicated and requires good knowledge in technics of measurement, which only in exceptional cases exsists within the building sector. The object of the present invention is to provide a test probe of the kind mentioned in the introcuction, by which the problems exsisting in the transmitter which now are present on the market have been eliminated. The distinguish¬ ing features of the invention are set forth in the claims mentioned below. Thanks to the invention one has now achieved a test probe which in an excellent way fulfils its purpose, at the same time as it is both cheep and easy to produce. By aid of the test probe according to the invention it is possible to already from the beginning, i.e. from the stage of produc¬ tion of a structural work to follow the development of the drying up of built in moisture, commonly called as building moisture, in the most of the building elements, as a struc¬ tural work consists of. Further the invention decreases the necessary knowledges of technics of measurement, which are required up to a minimum and minimizes sources of errors which otherwise can occur principally in that its active part is able to be applied in the building element itself during the production stage on the building site. This fact makes it possible to measure the moisture state undisturbed by outer factors, where you really want to do it and when¬ ever you want. Both actual test probe as well as indicating instrument are in fact much cheaper than that set of appa¬ ratus which today are present on the building market in¬ tended for similar applications. The test probe according to the present invention makes with other words for its appli¬ cation range a high quality in determination of actual mois¬ ture stage to a low price. The invention will now be further described below by aid of a preferred embodiment with reference to the drawings en¬ closed, in which Fig. 1 schematically illustrates a test probe according to the invention which is cast into a structural work and Fig. 2 schematically illustrates another embodiment of a test probe according to the invention in a condition cast into its position. As illustrated in Fig. l a preferred, first embodiment of a test probe 1 according to the present invention consists of such a formation which is fixable in a structutal material 2 already during the production stage. It is with other words possible to be cast into e.g. concrete directly which is unique within the moisture measurement range. The test probe l, which has such a quality that it can absorb and emit moisture in steam phase but not in liquid phase, includes an active part 3 consisting of a hygroscopic material, said part is enclosed in an outer, mechanical cover 4. The test probe 1 has that quality owing to that the cover 4 consists of an expanded plastic designed in such a way that water vapour can pass through it, but not water in a liquid phase. The cover 4 is also intended to prevent a break down of the active part 3 of the test probe l, which is exerted to pressure during casting into the concrete. The mechanical cover 4 is continuous as to its formation and is provided with a suppoting means 7 in one end of the same in the form of a threaded washer 8 for tightening of the test probe 1 in a position fixing means 9 for a temporary fixing of the same in connection with concrete casting. The active part 3 of the test probe 1 which consists of a hygroscopic material comprises in the example described of a round bar of wood having a diameter of about 6 mm. This material adjusts its relative humidity RF % to the relative atmospheric humidity RF % of the ambient material. Two unisolated electrodes 5 and 6 are inserted into the active part 3 thereby in making it possible to read the actual relative atmospheric humidity RF % of the test probe l. These electrodes 5,6 are sticked into the active part 3 of the test probe 1 a distance, which in the example illu¬ strated amounts to about 3-6 times the diameter of the active part 3. Those parts of the electrodes 5,6 which extend from the test probe l and through the concrete 2 and further to a resistance meter, not illustrated in the draw¬ ing, are isolated. On the electrodes 5,6 the electrical re¬ sistance is measured, which occurs between them, at actual moisture level. The resistance is indicated with a conven¬ tional resistance meter at different moisture levels. Since the magnitude of the resistance also is dependent of the temperature at the measuring place it is measured by a temperature indicator in the form of a thermistor 10 which is situated between the active part 3 of the test probe and the mechanical cover 4 and which is connected to a measuring equipment not illustrated in the drawing by a cable 12. Is the reading of the temperature other than 20°C the resis¬ tance reading is compensated by aid of a micro-processor. The instrument also can be equipped with an indicator which indicates the temperature measured in °C. The conversion of the temperature corrected resistance reading to relative hu¬ midity RF % occurs in that a resistance value for moisture between 75-97 % RF calibrated forward is fed into said micro-processor. It converts thereafter the right value in RF % to an indicator on the measuring instrument. In Fig. 2 is illustrated an modified embodiment of the test probe l according to the present invention. Here it is pri¬ marily the fixing itself of the test probe 1 in place which is different. Otherwise the construction is almost corres¬ ponding to that test probe illustrated in Fig. l. However, the supporting means 7 is here formed as a means of attach¬ ment 11. The electrodes 5 and 6 and the transmitter cable 12 are extending through this from the thermistor 10 by an opening 13. A round bar 14 is by its threading into the attachment means 11 intended both to unload said cables 5,6 and 12 in tension and to fix the test probe 1 during its casting into the structural material 2 which consists of concrete.

Claims: Cl aims 1. A test probe primarily intended to be applied in struc¬ tural material during the production- and/or building stage or when water damage has occured in a building and by which moisture measurement can be done undisturbed from outer factors in following the drying out process of built in moisture or other inconvenient, supplied moisture which can cause troubles in the form of mould and/or damages caused by putrefaction, as well as damages on floor cover-ings and other structural elements, characterized in an active part (3) consisting of a hygroscopic material, said part mostly is enclosed in an outer, mechanical cover (4) having a quality to allow passage of water steam but not water in liquid phase, at least two unisolated electrodes (5,6) provided in the active part (3) , said electrodes in an unisolated state extend from the test probe (1) through and out from the structural material (2) and up to a resistance meter for measuring electrical resistance which is present in the active part (3) between the electrodes (5,6) during actual moisture level and at least one thermistor (10) located between the active part (3) and the mechanical cover (4) and which by aid of a connecting cable is connected to a micro-processor for compensating of the resistance reading to measured temperature, said temperature corrected resis¬ tance reading hereafter is convertable to relative humidity (RF%) in that a resistance value calibrated forward for humidity between 75-97 % RF has been fed into the micro¬ processor, which after that by an indicator states the right value on the measured, relative humidity (RF) . 2. A test probe according to claim 1, characterized in that the mechanical cover (4) consists of a housing of expanded plastic and is designed to resist pressure during casting of the test probe (l) into concrete. 3. A test probe according to claim 1, characterized in that the active part (3) consists of a round bar of wood having a diameter of preferably 6 mm and a length of about 3-6 times said diameter. 4. A test probe according to claim l, characterized in that the unisolated electrodes (5,6) extend into the active part (3) a distance, which is at least 1/3 of its total, effective length. 5. A test probe according to any of preceeding claims, characterized in that the mechanical cover (4) is elongated and in its one end provided with a supporting means (7) in the form of a threaded washer (8) for thight- ening in a position fixing means (9) for temporary fixing of the test probe (l) in connection with concrete casting. 6. A test probe according to any preceeding claims, characterized in that the mechanical cover (4) in one of its ends fixed to a supporting means (7) in the form of attachments means (11), by which the electrodes (5,6) and a tramsmitter cable (12) from the thermistor (10) extend via an opening (13) out to and through the structural material (2) , and in said means (11) a position fixing means in the form of a round bar (14) is threaded, both to unload the electrodes and the transmitter cable (12) in the opening (13) in tension and also to fix the test probe (1) during its casting into e.g. concrete being the structural material (2) . AMENDED CLAIMS [received by the International Bureau on 17 January 1994 (17.01.94); original claims 1 and 2 replaced by amended claim 1; claims 3-6 renumbered as claims 2-5 (2 pages)] 1. A test probe primarily intended to be applied in struc¬ tural material during the production- and/or building stage or when water damage has occured in a building and by which moisture measurement can be done undisturbed from outer factors in following the drying out process of built in moisture or other inconvenient, supplied moisture which can cause troubles in the form of mould and/or damages caused by putrefaction, as well as damages on floor coverings and other structural elements, characterized in that said test prob comprises an active part (3) consisting of a hygroscopic material, mostly enclosed in an outer mechani¬ cal cover (4) having a quality to allow passage of water steam but not water in liquid phase and said cover (4) consists of a housing of expanded plastics and is designed to resist pressure during casting of the test probe (l) into concrete, at least two unisolated electrodes (5,6) provided in the active part (3) , said electrodes in an unisolated state extend from the test probe (l) through and out from the structural material (2) and up to a resistance meter for measuring electrical resistance which is present in the active part (3) between the electrodes (5,6) during actual moisture level, and at least one thermistor (10) located between the active part (3) and the mechanical cover (4) and which by aid of a connecting cable is connected to a micro¬ processor for compensating of the resistance reading to measured temperature, said temperature corrected resistance reading hereafter is convertable to relative humidity (RF%) in that a resistance value calibrated forward for humidity between 75-97 % RF has been fed into the micro-processor, which after that by an indicator states the right value of the relative humidity (RF) measured. 2. A test probe according to claim I, characterized in that the active part (3) consists of a round bar of wood having a diameter of preferably 6 mm and a length of about 3-6 times said diameter. 3. A test probe according to claim 1, characterized in that the unisolated electrodes (5,6) extend into the active part (3) a distance, which is at least 1/3 of its total, effective length. . A test probe according to any of preceding claims, characterized in that the mechanical cover (4) is elongated and in its one end provided with a supporting means (7) in the form of a threaded washer (8) for thight- ening in a position fixing means (9) for temporary fixing of the test probe (1) in connection with concrete casting. 5. A test probe according to any of preceding claims, characterized in that the mechanical cover (4) in one of its ends is fixed to a supporting means (7) in the form of an attachment means (11), through which the electrodes (5,6) and a tramsmitter cable (12) from the thermistor (10) extend via an opening (13) out to and through the structural material (2) , and in said means (11) a position fixing means in the form of a round bar (14) is threaded, both to unload the electrodes and the transmitter cable (12) in the opening (13) in tension and also to fix the test probe (1) during its casting into e.g. concrete being the structural material (2) .

Inventors: SAHLEN NICKLAS, SAHLEN, NICKLAS
Applicants: SAHLEN NICKLAS, SAHLENS FUKTKONTROLL
Application year: 1993
Main classification: G01N27
IPC codes: G01N27, G01N33