DK168176B1

DK168176B1 - Humidity indicator with hygroscopic salt

Info

Publication number: DK168176B1
Application number: DK182790A
Authority: DK
Inventors: Lars Olsen; Erik Frederiksen
Original assignee: Dansk Teknologisk Inst
Priority date: 1990-07-31
Filing date: 1990-07-31
Publication date: 1994-02-21
Also published as: DK182790D0; AU8322591A; WO1992002802A1; DK182790A

Description

i DK 168176 B1in DK 168176 B1

Opfindelsen angår en fugtighedsindikator af den art, der er angivet i krav l’s indledning.The invention relates to a humidity indicator of the kind set forth in claim 1.

Der findes mange forskellige typer af fugtighedsindika-5 torer, der er baseret på hygroskopiske salte, der gøres flydende af luftens fugtighed, og størsteparten af disse indikatorer er bestemt til at indikere, hvorvidt luftens relative fugtighed er eller har været i det mindste lig med henflydningstærsklen for det hygroskopiske salt, der 10 anvendes i hvert tilfælde. Med disse kendte fugtigheds-indikatorer er det imidlertid ikke muligt at opnå nogen indikation af varigheden af de tidsintervaller, hvorunder luftens relative fugtighed har været lig med eller større end en bestemt værdi.There are many different types of humidity indicators based on hygroscopic salts liquefied by the humidity of the air, and the majority of these indicators are intended to indicate whether the relative humidity of the air is or has been at least equal to the flow threshold. for the hygroscopic salt used in each case. However, with these known humidity indicators, it is not possible to obtain any indication of the duration of the time intervals during which the relative humidity of the air has been equal to or greater than a certain value.

15 Det er opfindelsens formål at anvise udformningen af en fugtighedsindikator af den indledningsvis omtalte art, hvormed det er muligt at opnå en indikation på den samlede varighed af de tidsintervaller, hvorunder den relative fugtighed i den luft, der omgiver indikatoren, har 20 været lig med eller større end en bestemt værdi, og dette formål opnås med en indikator, der ifølge opfindelsen tillige udviser de træk, der er angivet i krav l's kendetegnende del.It is an object of the invention to provide the design of a humidity indicator of the type mentioned above, by which it is possible to obtain an indication of the total duration of the time intervals during which the relative humidity in the air surrounding the indicator has been equal to or greater than a certain value, and this object is achieved by an indicator which according to the invention also exhibits the features specified in the characterizing part of claim 1.

Med denne anordning opnås, at væske i alt væsentligt kun 25 overføres fra den første til den anden beholder under de tidsintervaller, under hvilke den omgivende lufts relative fugtighed har været lig med eller større end den nævnte bestemte værdi. Således er mængden af den overførte væske, som kan måles ved at iagttage væskeniveauet i den anden 30 beholder, en indikation af den nævnte samlede varighed. Eftersom fugtighedsindikatoren ifølge opfindelsen ikke indeholder bevægelige dele eller præcisionskrævende dele, kan den fremstilles med meget lave omkostninger.With this device, liquid is obtained substantially only from the first container to the second container during the time intervals during which the relative humidity of the ambient air has been equal to or greater than said particular value. Thus, the amount of liquid transferred, which can be measured by observing the liquid level in the second container, is an indication of the total duration mentioned. Since the humidity indicator of the invention does not contain moving parts or precision parts, it can be manufactured at very low cost.

DK 168176 B1 2DK 168176 B1 2

Hensigtsmæssige udførelsesformer for fugtighedsindikatoren ifølge opfindelsen, hvis virkninger er nærmere forklaret i den efterfølgende specielle del af nærværende beskrivelse, 5 er angivet i krav 2-8.Suitable embodiments of the moisture indicator according to the invention, the effects of which are explained in more detail in the following special part of this specification, are set out in claims 2-8.

Opfindelsen skal i det følgende forklares nærmere under henvisning til et udførelseseksempel på en fugtighedsindi-kator ifølge opfindelsen, der er vist på tegningen, idet fig. 1 er et lodret snit gennem indikatoren i dennes til-10 stand før brugen, og fig. 2 er et billede svarende til fig. 1, men viser indikatoren, efter at denne har været i drift i nogen tid, og fig. 3 er et billede af en tænkt laboratorie-opstilling, der belyser opfindelsens princip.BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail below with reference to an embodiment of a humidity indicator according to the invention shown in the drawing. 1 is a vertical section through the indicator in its condition prior to use; and FIG. 2 is a view similar to FIG. 1, but shows the indicator after it has been in operation for some time; and FIG. 3 is a view of an imagined laboratory arrangement illustrating the principle of the invention.

15 Den fugtighedsindikator, der er vist på tegningen, består af et hus 1 i form af et opadtil åbent bæger med en skråtliggende bund 2. For at huset 1 skal kunne stå på en vandret understøtningsflade er det udformet med en hul fod 3, hvis underkant kan hvile på den nævnte understøtningsfla-20 de. Bortset fra sin opadvendende munding, der som vist i fig. 1 kan være lukket af en hætte 5, er huset 1 lufttæt og væsketæt. 1 det mindste nogle dele af huset 1 er gennemsigtige for at gøre det muligt at se, hvad der sker inden i det.The humidity indicator shown in the drawing consists of a housing 1 in the form of an upwardly open cup with an inclined bottom 2. In order for the housing 1 to stand on a horizontal support surface, it is formed with a hollow base 3, the lower edge of which is may rest on said support surface. Except for its upward opening, which as shown in FIG. 1 may be closed by a cap 5, the housing 1 is airtight and liquid tight. 1 at least some parts of the housing 1 are transparent to enable you to see what is happening inside it.

25 I den øvre del af huset 1 er der anbragt en lomme 6 med et mellemrum 7 mellem lommen 6 og huset 1. Lommen 6 er udformet på en sådan måde, at den som vist i fig. 2 kan indeholde en væskemængde.In the upper part of the housing 1 a pocket 6 is provided with a space 7 between the pocket 6 and the housing 1. The pocket 6 is designed in such a way that, as shown in FIG. 2 may contain a quantity of liquid.

En væge 8 strækker sig fra den nederste del af lommen 6, 30 omkring lommens overkant og ned gennem mellemrummet 7, således at den ender ved et niveau under niveauet for 3 DK 168176 B1 lommen 6's bund.A wick 8 extends from the lower portion of the pocket 6, 30 around the top of the pocket and down through the gap 7 so that it ends at a level below the level of the bottom of the pocket 6.

I begyndelsestilstanden, dvs. før den tages i brug, befinder indikatoren sig i den i fig. 1 viste tilstand, hvori 5 lommen 6 indeholder et kvantum hygroskopisk salt, og huset er lukket af hætten 5 på en sådan måde, at luft ikke kan komme ind i huset eller salt 9 undvige fra lommen 6, idet sidstnævnte er lukket af hætten 5, der indgriber med lommens overkant.In the initial state, i.e. prior to use, the indicator is in the FIG. 1, wherein the pocket 5 contains a quantity of hygroscopic salt and the housing is closed by the cap 5 in such a way that air cannot enter the housing or salt 9 evades from the pocket 6, the latter being closed by the cap 5, that engages with the top of the pocket.

10 Følgende tabel viser eksempler på forholdsvis uskadelige hygroskopiske salte, der kan anvendes som det hygroskopiske salt 9, der er anbragt i lommen 6.The following table shows examples of relatively harmless hygroscopic salts which can be used as the hygroscopic salt 9 placed in the pocket 6.

TabelTable

Bliver fly- ml H2OBecomes aircraft ml H2O

15 dende ved rel. tilført for fugtighed at gøre (20°C) 100 g salt flydende _(0-20°C) 20 Kobberchlorid-anhydrid 68,4% 14215 by rel. added to humidity to make (20 ° C) 100 g of salt liquid _ (0-20 ° C) 20 Copper chloride anhydride 68.4% 142

Kobberchlorid-dihydrat 68,4% 90,6Copper chloride dihydrate 68.4% 90.6

Natriumchlorid 75,5% 280Sodium Chloride 75.5% 280

Ammoniumsulfat 81,0% 142Ammonium sulfate 81.0% 142

Kaliumchlorid 86,0% 288 25 Kaliumnitrat 93,2% 752Potassium chloride 86.0% 288 Potassium nitrate 93.2% 752

Kaliumsulfat 97,1% 833 Når fugtighedsindikatoren skal tages i brug, anbringes den på det sted, hvor man ønsker at overvåge luftens relative 30 fugtighed, hvorefter hætten 5 aftages, vendes om og igen påsættes, således at den beskytter det indre af huset 1 mod støv eller nedfaldende puds og lignende, men samtidigt DK 168176 B1 4 tillader rummet inden i huset 1 at stå i forbindelse med den omgivende luft gennem et antal ventilationsslidser 10, der er udformet i omkredsen af hætten 5's "krone". Luften 5 inden i huset 1 vil nu komme i ligevægt med luften udenfor, således at en eventuel fugtighed i sidstnævnte vil påvirke det hygroskopiske salt 9. Dersom den relative fugtighed af den luft, der kommer i berøring med det hygroskopiske salt 9 er lig med eller højere end henflyd-10 ningstærsklen for det pågældende salt 9, der anvendes, vil saltet absorbere fugtighed fra luften og opløses i denne fugtighed, således at lommen 6 nu vil indeholde et kvantum væske 11, der er en opløsning af saltet 9 i det fra luften absorberede vand.Potassium sulphate 97.1% 833 When the humidity indicator is to be used, it is placed at the place where it is desired to monitor the relative humidity of the air, after which the cap 5 is removed, turned over and over again to protect the interior of the housing 1 from dust or falling plaster and the like, but at the same time allows the space within the housing 1 to communicate with the surrounding air through a number of ventilation slots 10 formed in the circumference of the "crown" of the cap 5. The air 5 inside the housing 1 will now equilibrate with the air outside, so that any humidity in the latter will affect the hygroscopic salt 9. If the relative humidity of the air coming into contact with the hygroscopic salt 9 is equal to or higher than the influx threshold of the particular salt 9 used, the salt will absorb moisture from the air and dissolve in that moisture, so that the pocket 6 will now contain a quantity of liquid 11 which is a solution of the salt 9 in it from the air. absorbed water.

15 Så snart væskestanden i væsken 11 er nået op på et niveau, hvor vægen 8 kan absorbere væsken og overføre den gennem mellemrummet 7 og til vægens nederste ende, vil væske blive overført fra lommen 6 langs med vægen 8, idet den forlader sidstnævnte i form af dråber, der falder ned i et 20 kar 12, der er dannet af den nederste del af huset 1, herunder dettes skråtliggende bund 2.Once the liquid level in the liquid 11 has reached a level where the wall 8 can absorb the liquid and transfer it through the gap 7 and to the lower end of the wall, liquid will be transferred from the pocket 6 along with the wall 8 leaving the latter in form. of droplets falling into a vessel 12 formed by the lower portion of housing 1, including its inclined bottom 2.

Efter et tidsrum vil et større eller mindre kvantum væske have ansamlet sig i karret 12. Mængden af den væske, der er opsamlet i karret 12, vil nu være et mål for den sam-25 lede varighed af de tidsintervaller, under hvilke fugtigheden har været lig med eller større end henflydningstærsklen for det hygroskopiske salt 9. Den skråtliggende bund 2 gør det lettere at måle små væskemængder, f.eks*. ved aflæsning af en ikke vist skala på huset l's ydervæg.After a period of time, a larger or smaller quantity of liquid will have accumulated in the vessel 12. The amount of the liquid collected in the vessel 12 will now be a measure of the total duration of the time intervals during which the humidity has been equal to or greater than the flow threshold of the hygroscopic salt 9. The inclined bottom 2 makes it easier to measure small amounts of liquid, eg *. by reading a scale not shown on the outer wall of the housing 1.

30 Huset 1 og lommen 6 er fortrinsvis fremstillet af gennemsigtigt plastmateriale, såsom acrylharpiks, således at det kan ses, hvorvidt det hygroskopiske salt 9 vedblivende er tørt i tilstanden før brugen, og at væskestanden i karret 12 kan iagttages, når indikatoren er i brug.The housing 1 and pocket 6 are preferably made of transparent plastic material, such as acrylic resin, so that it can be seen whether the hygroscopic salt 9 remains dry in the state before use and that the liquid level in the vessel 12 can be observed when the indicator is in use.

5 DK 168176 B15 DK 168176 B1

Under opbevaring før brugen er det selvsagt vigtigt at forhindre fugtighed fra den omgivende luft i at påvirke det hygroskopiske salt 9. Dette kunne opnås ved at 5 anbringe en ikke vist patron indeholdende et tørremiddel, såsom kiselgel, på indersiden af hætten 5, eller ved at anbringe hele indikatoren i en passende pose eller beholder, der også indeholder en på passende måde indesluttet portion af et sådant tørremiddel.During storage prior to use, it is of course important to prevent moisture from the surrounding air from affecting the hygroscopic salt 9. This could be accomplished by applying a cartridge containing a desiccant, such as silica gel, to the inside of the cap 5, or by place the entire indicator in a suitable bag or container which also contains an appropriately enclosed portion of such desiccant.

10 Hætten 5 kan være fremstillet af passende uigennemtrængeligt og eftergivende materiale, såsom kunstgummi eller andet elastomert stof.The cap 5 may be made of suitably impervious and resilient material such as synthetic rubber or other elastomeric fabric.

Vægen 8 kan bestå af et hvilket som helst egnet materiale, der kan befugtes af vand, såsom "silkepapir" eller så-15 kaldt cigaretpapir. Andre materialer, herunder tekstilstoffer, kan også anvendes.The wall 8 may consist of any suitable material which can be wetted by water, such as "tissue paper" or so-called cigarette paper. Other materials, including textile fabrics, may also be used.

Fugtighedsindikatoren kan være ganske lille, eftersom dens funktionsevne ikke afhænger af dens størrelse. En samlet højde på mellem 10 og 30 mm har været påtænkt.The humidity indicator can be quite small, since its functionality does not depend on its size. A total height of between 10 and 30 mm has been envisaged.

20 Det skal for god orden skyld nævnes, at indikatoren ifølge opfindelsen i princippet kan fungere uden andre dele end de primært aktive, nemlig - lommen 6, saltportionen 9, 25 - den kapillært virkende væge 8, og karret 12, eller hermed ækvivalente dele, samt organer af en eller anden art, såsom et stativ, til at holde delene i de rigtige indbyrdes stillinger og orienteringer. Hvis man 30 således forestiller sig, at det i fig. 1 og 2 viste udførelseseksempel - under brug af f.eks. en kemikers laboratorieudstyr - erstattes som vist i fig. 3 af et første bægerglas 6’ i stedet for lommen 6, anbragt højt oppe i et stativ, DK 168176 B1 6 et andet bægerglas 12' i steder for karret 12, anbragt lavere end det første, f.eks. på det bord, som stativet står på, 5 - en portion hygroskopisk salt 9’ svarende til saltet 9 i det første bægerglas 6', samt en strimmel filtrerpapir 8', der strækker sig fra rummet i det første bægerglas 6’ over dettes kant og ned til et sted over eller i det andet bægerglas 12' i 10 stedet for vægen 8, så vil dette "barberede" udstyr fungere på nøjagtigt samme måde som den i fig. 2 viste indikator.In good order, it should be mentioned that the indicator according to the invention can in principle function without parts other than the primary active, namely - the pocket 6, the salt portion 9, 25 - the capillary-acting wick 8, and the vessel 12, or equivalent parts, and means of some kind, such as a tripod, for holding the parts in the proper positions and orientations. Thus, if one imagines that in FIG. 1 and 2 - using e.g. a chemist's laboratory equipment - replaced as shown in fig. 3 of a first beaker 6 'instead of the pocket 6, placed high up in a rack; on the table on which the stand stands 5 - a portion of hygroscopic salt 9 'corresponding to the salt 9 of the first beaker 6', and a strip of filter paper 8 'extending from the space of the first beaker 6' over its edge and down to a location above or in the second beaker 12 'in place of the wall 8, then this "shaved" equipment will operate in exactly the same manner as that of FIG. 2.

I praksis foretrækkes imidlertid den viste udførelsesform, eftersom den yder beskyttelse både inden indikatoren tages 15 i brug og under driften.In practice, however, the embodiment shown is preferred since it provides protection both before the indicator is put into operation and during operation.

iin

Claims

Humidity indicator for the indication of humidity and of the nature of which is based on a hygroscopic substance which, upon exposure to air of at least a predetermined degree of moisture, absorbs water from the air and dissolves in this water, characterized by (a) a first container (6) whose interior during use is in open communication with the ambient air, said first container being liquid-tight at least up to a certain level and, prior to use of the indicator, containing a predetermined amount of said hygroscopic substance, b ) a second container (12) which, during use, is located at a lower level than the first container (6), the second container also being liquid-tight at least up to a certain level, and c) liquid transfer means (8), arranged to transfer liquid from a first area of the first container (6) at or near its bottom to a second area outside the first container and by a capillary action at a lower level than its bottom level, from which second area the liquid transfer means (8) can deliver liquid to the second container (12).

Indicator according to claim 1, characterized in that said liquid transfer means comprise at least one wick (8) capable of being wetted by water.

Indicator according to claim 1 or 2, characterized in that. the second container consists of the area near the bottom of a casing (1) which is liquid-tight downwards and toward the sides, in which casing the first container (6) is in the form of an upwardly open pocket, and wherein the liquid transfer means (8 ) extends through at least one slot (7) between the pocket and a wall of the casing away from the pocket. DK 168176 B1 8

Indicator according to claim 3, characterized in that the casing 1 is arranged to be sealed in a vapor-tight manner from the ambient air, e.g. using a removable, 5 tight-fitting cap or plug (5).

Indicator according to claim 4, characterized in that the cap or plug (5) is arranged to close the first container (6) in such a way that the connection between the inner thereof and the rest of the inner space of the casing (1) is 10. substantially disconnected.

Indicator according to one or more of claims 1-5, characterized in that a) the horizontal cross-sectional area of the second container (12) during use decreases downwards from a final size to substantially zero, and b) that the second container (12) at least in or near its lower portion is at least partially translucent or transparent.

Indicator according to one or more of claims 4-6, 20, characterized in that the first container (6) comprises at least one transparent wall area through which its contents (9, 11) can be viewed.

Indicator according to one or more of claims 1-7, characterized in that the hygroscopic substance is selected from the group of salts consisting of copper chloride anhydride, copper chloride dihydrate, sodium chloride, ammonium sulfate, potassium nitrate, potassium chloride and potassium sulfate.