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Temperature measurement result obtained by using an
electronic thermometer with an outside temperature
sensor, in a casing made out of a stainless steel pipe, becomes
stabilized with certain speed resulting from:
It means, that after placing a sensor in a measured medium (air,
liquid, refined material etc.), which temperature is different from a
sensor’s temperature by a value “delta u” (on a graph’s vertical axis),
the sensor’s temperature will gradually (unfortunately not immediately)
get close to the temperature of a measured medium. A typical course of
changes as a result of temperature measurement was introduced on a
graph in a time function (on a horizontal axis). Characteristic times
for the chosen sensor sizes and for two different media (water and air)
were provided in the table below. For different media - time constants
usually are going to stay between data for those two media mentioned in
the table.
The fact that is worth mentioning is that:
THE
SENSORS WITH THE SHIELDS MADE OUT OF THE ACID RESISTANT STEEL PIPES
1H18N9T DIMENSION (pipe diameter x wall’s thickness) |
CHARACTERISTIC TIMES (in
seconds) |
|||
---|---|---|---|---|
water, flow 0,4 m/s | air, flow 1,0 m/s | |||
T 0,5 |
T 0,9 |
T 0,5 |
T 0,9 |
|
3 x 0,25 |
7 |
19 |
35 |
95 |
4 x 0,35 |
12 |
32 |
45 |
125 |
5 x 0,35 |
17 |
45 |
70 |
190 |
6 x 0,35 |
22 |
61 |
80 |
235 |
8 x 0,60 |
27 |
72 |
105 |
310 |
10 x 1,60 |
35 |
96 |
140 |
375 |
12 x 2 |
51 |
138 |
165 |
420 |
Producent: LAB-EL Elektronika Laboratoryjna Sp. J. ul. Bodycha 68b, 02-495 Warszawa tel: (022) 667 71 18, 0601 209656, fax: (022) 867 53 32 poczta elektroniczna: info@label.com.pl witryna internetowa: http://www.label.com.pl internetowa stacja meteorologiczna: http://www.meteo.waw.pl stacja meteorologiczna w komórce: wap.meteo.waw.pl Ostatnia aktualizacja: 23.06.2007 |