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Accessories

Ceramic Protection Tubes

Ceramic protection tubes are supplied only in form A.

Standard nominal lengths are 355 mm, 500 mm, 710 mm and 1000 mm. Other nominal lengths like 1400 mm and 2000 mm are available on request.

The ordering code of this product is composed of its form, dia., identification letters of the material number and protection tube length. Please refer to our Product Information "Straight Thermocouples" regarding the relation between protection tube length and nominal length.

Example: A15CZ-1030

d1 1)
s min
For straight thermocouples model AK, AKK, BK und BKK
Protection
tube material

Temperature
shock
resistance

Tightness 3)

Permitted
permanent
temperature
in °C 2)
355500710100014002000
Protection tube length l 3
Permitted deviation +3 / -0Perm. Deviation +5 / -0
101,53755207301020--C 610
(K610)
Medium
to
good

Gas-tight

1500
15/162-53074010301430-
242,5-530740103014302030
1023755307401030--C 799
(K710)
Medium
to
good

Gas-tight

1600
15/162,5-53074010301430-
243-530740103014302030
264--740103014302030C 530Very goodPorous1500
20 5)5-53074010301430-
SiSiC 4)

Very good

Gas-tight

1350
22 6)5-530740103014302030
25 6)5-53074010301430230
20 6)3,5-53074010301430-
RSiC 4)

good

Gas-tight

1600
22 6)3,5-530740103014302030
25 7)3,5-5307401030 2030

Identification letter for ceramic protection tubes
Ident.
Letter
Material acc. to
DIN EN 60 672
Old norm VDE 0335 Part 1
CXC 530 / K 530
CYC 610 / K  610
CZC 710 / K 710
RSiCSilicon carbide, recrysallized ²
SiSiCSilicon carbide, recrysallized ²

 d1 must be maintained over a length of 20 mm with an permitted deviation of +/- 0.5 mm.

Noble-metal thermocouples are predominantly used for measuring temperatures above 1000 °C. When installed in protection tubes and insulation rods made from the above indicated ceramic insulation materials, it has to be taken into account that in a reducing atmosphere the thermocouples may be affected. Of particular influence and reducing the admissible permanent temperature are silicon and heavy metals. 

At temperatures above approx. 1000 °C gas-tightness can no longer be assumed. 

 When using SiC protection tubes type AK only non-precious-metal thermocouples should be installed. With type AKK the installation of an inner protection tube made of C 799 is strongly recommended when having noble-metal thermocouples. 

Type AKK: inner protection tube 6 x 1

Type AKK: inner protection tube 10 x 2

Type AKK: inner protection tube 15 x 2.5


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