Nominal resistance value is 1000hms at 32° F with a tolerance of ± 0.1 ohm. Standard bulbs have platinum or Nickel wound resistance elements, with hardglass or ceramic base, for temperature measurements in the range From – 418 to +1560° F. One, two or three windings are available on the same bulb.
Resistance thermometer bulbs always take up the mean value of the temperature operating over the full winding length, therefore it is important that the full lenght of the element be exposed to the medium whose temperature is to be measured.
Trouble free working of resistance thermometer bulbs is dependent on proper care being taken in their Installation and the selection of associated components used for this purpose. For this reason we recommend the use of TM resistance inserts. TM resistance thermometer inserts are built-up from nickel or st. st. tube.
Standards inserts size are 4,6 or 8mm O.D. Sillimanite insulators with MgO or alumina powder filling, to have good resistance to vibrations and shocks, are used as standard. Resistance thermometer bulbs conforming to most other known international standard are already available upon request.