Termočlánková a kompenzační vedení

Thermocouple and compensating leads WATLOW

Why is this lead necessary..

Thermocouple leads are featured by the fact that they are made from identical material as that of the thermocouple itself. Therefore there are also types J, K,... Thanks to the aforementioned no other joint represents (e.g. clamps between thermocouple and sequential lead) new thermocouple. If we used a common conductor it would result in a joint of two different materials and it would give rise to another thermocouple that would generate voltage depending on the temperature of this joint. This voltage would be added to the voltage of the thermocouple itself, which would result in impairment and degradation of measured value.

Compensating leads are cheaper substitution of the thermocouple lead. The compensating leads are made from noble metals – the material, which is not identical with that of thermocouple metal. Despite these nonconformities the compensating leads maintain similar parameters as thermocouples do however it is valid only for temperatures up to 200°C (exceptionally up to the temperatures 260 °C ). For higher temperatures it is necessary to use thermocouple leads. These leads are divided as follows J, K,..

However for both leads applies as valid principle that the longer is the lead the higher level of error is brought into the sensor measurement, which means the error due to lead resistance (the sensor generates voltage levels represented by values of the order of a few tens mV

For the thermocouples of E, J, K, N, T, B, C, R and S types
Diameters of conductors 1.3, 0.8, 0.5, 0.3, 0.25 mm
Temperature resistance 100, 200, 260, 480, 700, 980, 1200 °C
Resistance to moisture, oils and other chemical substances
Solid wire, stranded wire – for both fixed and movable fit
Double insulation - selection of materials for every application
Electric shielding, twisting – increasing of resistance to interference
Stainless steel braid – the increase of mechanical resistance, food- processing industry

Basic types of thermocouple insulations and compensation leads:

Internal insulation	External insulation	Max. temperature
PVC	PVC	105 °C
FEP (fluoroplastic)	FEP	260 °C
TFE, fibreglass	ServTex	316 °C
TFE	TFE	316 °C
Fibreglass	ServTex	343 °C
Polyimide (sintered kapton)	Polyimide	427 °C
Fibreglass	Fibreglass	538 °C
Double fibreglass wrapping	Fibreglass	538 °C
High temperature fibreglass	High temperature fibreglass	871 °C
Silicone fibre	Silicone fibre	1093 °C
Ceramic fibre	Ceramic fibre	1427 °C

Types of leads being used most frequently, mostly available in stock

Designation	Type	Diameter	Type	Insulation	Temperature	Price per/m
J20-5-510	J	0.8mm	Compensation, solid wire, standard. accuracy	PVC/PVC	105°C	-
K20-5-510	K	0.8mm	Compensation solid wire, standard accuracy	PVC/PVC	105°C	-
S20-5-510	S	0.8mm	Compensation solid wire, standard. accuracy	PVC/PVC	105°C	-
J20-3-S-304	J	0.8mm	Thermocouple stranded conductor standard. accuracy metal braided screening	Glass fibre	538°C	-
K14-2-350	K	1.6mm	Thermocouple solid wire, increased accuracy	Ceramic fibre	1427°C	-
K20-3-S-304	K	0.8mm	Thermocouple stranded conductor, standard accuracy,metal braided screening	Glass fibre	538°C	-

With respect to large scope of assortment and big number of variations it is necessary to ask for particular price for particular leads by phone. In case of larger scope purchase the price is set on the basis of mutual agreement, i.e. on individual basis.

Files to be downloaded	Language	Number of downloads	Size
Catalog of SERV-RITE leads	Czech	[ 2836 ]	[79kB]