Datasheet

FUNCTION / OPERATION
Temperature Recording Labels
CelsiStrip
®
CelsiClock
®
CelsiDot
®
CelsiPoint
®
PRINCIPLE OF OPERATION
The basic function of the CelsiLabel® depends on the
melting point (a well defined physical action) rather than
a chemical reaction to translate the temperatures level(s)
into visible form. There are also temperature indicators on
the market whose indications are based on chemical reac-
tions of the indicating materials used. Such chemical reac-
tions depend obviously on both the temperature AND the
exposure time.
SPIRIG manufactures only physical response temperature
recording labels. Exposure time does not alter or modify
the readings.
FUNCTION
CelsiLabels®
use the melting point of chemicals. The prin-
ciple is described here in a simplified way. A black blotting
paper is covered with a white chemical coating. The black
colour is hidden under the white coating. If the white coat
would melt, then the liquefied coating material will be
drawn by capillary forces into the black paper. The black
paper becomes visible.
Worst case tolerance: ± 2,5% (of full scale).
The now black paper surface is the 100% irreversible proof
that the coating exceeded its specific melting point some-
times in the past (seconds or a year) and was in a liquid
state to penetrate the black paper.
The CelsiLabel® combine chemicals with different melting
points, levels arranged in an increasing scale like on a
thermometer.
RULE NO. 1
The "graying" of the white sensitive coating is NOT an indi-
cation of an exceeded temperature level. It is an aging pro-
cess depending on many factors, one of them being time,
environment, etc.
Graying is not a displacement of the coating material, and
consequently the melting point is or was not exceeded.
RULE NO. 2
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 CelsiLabel® 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.
Shelf life limitation:
There is basically no theoretical shelf life limitation on the
phase change process and dislocation of the thermomelt
material, however there is a degrading with time and ambi-
ent storage temperature level for the "permeability / wetta-
bility" of the black background substrate by the melt materi-
al. Another shelf life limiting factor is the tendency of the
adhesive layer to "dry" and loose tackiness with time.
Expected shelf life: 12 month after Spirig's delivery.
Storage:
Dry, cool, no light and sealed in plastic envelope / sachet.
Interpretation of Readings on Labels
Aging and other influences might alter the surface
colour from white to grey. Questions on how to un-
derstand the indication might arise after application.
If the thermo sensitive area exposes the black paper
background, then its specific temperature has been
exceeded. The background paper is of a deep black
colour. If there is still an uncertainty left, then the fol-
lowing test will give a clear answer:
Carefully remove label from test surface. Use a small hot
soldering 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 not been previously exposed above its rated tempera-
ture level.
Reasons for potential errors in applications
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. A major measurement error
might occur. The strip will not measure the surface temper-
ature to which it is applied. The CelsiLabel® is put behind a
shield (into the "heating" shadow) protecting the
CelsiLabel® from direct exposure to the heat radiation.
FUNCTION TEST
Two CelsiStrips are applied here on a 100 mm thick by 250 x 250
mm 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.
Warranty:
Spirig Quality Control try's to ship only performing materials. By the nature of
the 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.
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E-Shop: www.celsi.com IT2CS00_Funktion 1 / 1 print: 15.06.2003
PHONE: [phone] FAX: [phone] [e-mail] WWW.SPIRIG.COM
DIPL.-ING. ERNEST SPIRIG POBOX 1140 HOHLWEG 1 CH-8640 RAPPERSWIL