Function and Operation of the CELSISTRIP® Temperature Monitoring / Recording Labels
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AND the exposure time. SPIRIG manufactures irreversible temperature recordinglabels responding only to physical changes. Exposure time does not alter or modify the readings. > The basic function of the CelsiLabelή depends on the > melting point (a well defined physical action) of chemicalcompounds, rather than on a chemical reaction between reagents to translate the temperatures level(s) into visible form. There are temperature indicators on the market whose indication are based on chemical reactions of the materials used. Such chemical reactions depend on thetemperature not been previously exposed above its rated tempera-ture level. Carefully remove label from test surface. Use a small hotsoldering iron tip and touch the heat sensitive area from the adhesive side of the label. If the sensitive area responds within parts of a second by blackening, then that specific temperature level on the label had > CelsiLabels A black "blotting" paper is covered with a white chemical coating. The black paper is hidden under the white coat- ing. If the white coating melts, then the coating material material will be drawn by capillary forces into the black paper. The black paper becomes visible. The material transfer is irreversible. > use the melting point of chemicals. In a sim-plified description the function is as follows: > The strip should not be exposed to direct radiation of in-frared heating energy or ultraviolet UV curing light. The strip and its heat sensitive surface areas will absorb heat radiation at a different absorption rate (or reject heat at a different reflection rate) than the target surface the temper- ature should be monitored does. A major measurement er- ror might occur. The strip will not measure the surface tem-perature to which it is applied. The CelsiLabelή is put be-hind a shield (into the "heating" shadow) protecting the CelsiLabel from direct exposure to the heat radiation. > The white to black changed surface is the 100% irreversi-ble proof that the coating exceeded its specific meltingpoint at some time in the past (a few seconds or a yearago).The CelsiLabel combines compounds with different melt-ing points, levels arranged in an increasing scale like athermometer. > The "graying" of the white thermo-sensitive coating is NOTan indication of an exceeded temperature level. This is anaging process depending on many factors, one of them be-ing time, environment, etc. Graying is not a displacement of the coating material, andconsequently the melting point is or was not exceeded. > The melting point slightly depends on the ambient air pres-sure imposed on the chemicals. In general materials melt-ing points do depend more or less on the pressures ap- plied. The ratings on the CelsiLabelή are for usual ambi- ent atmospheric pressures between sea level and up to 1000 meters (3000 feet). If an application is either in a pressure or a vacuum cham-ber, the user has to "cross-reference" the readings printed on the labels against his specific pressure or vacuum in use. > CST_10954_0945r.jpg Two CelsiStrips are applied here on a 100 mm thick by 250 x 250mm wide aluminum plate electro heated from below. A thermocou- ple wire ends 3 mm deep in a hole in the center of this plate. The heavy thermal mass of the plate ensures in the center of its sur- face an even temperature level. The high mass also limits the tem- perature rate of increase (gradient) at a given electric heating in- put. The colour change from white to black can easily and clearly be seen. The test can also be put on a video, eg using the almost "for free" iMovie software from Apple. With a convenient arrange- ment it would also be possible to "mirror in" the the temperature measurement values from the electronic thermometer or to store the spoken out read values of the meter. There is basically no theoretical shelf life limitation on the phasechange process and dislocation of the thermosensitive melt mate- rial. There might develop with time a slight loss of phase change speed / response of the wetting / starting of capillary forces pulling the white compounds into the black carrier. There is also a slight degrading of the adhesive layer tackiness with storage time. Storage conditions should be: Dry, cool, no light. Labels left sealed in the original plasticenvelope / boxes as supplied. Warranty : > Spirig Quality Control try's to ship only performing materials. By the nature ofthe product a 100% test is impossible. In case of a material failure warranty covers explicitly only the materials exchange provided storage was correct. Any other warranties, claims or obligations for Spirig towards the customer / user are explicitly excluded and void. Shelf life: 18 month minimum > Life tests showed that even after 5 years the CelsiLabelήs operate perfect. size="-2">