Contraction size of high-temperature thermocouples

The thermocouple on the stove has just shown its tip.

On our end, it has shrunk by about 3 centimeters; it won’t take long before we need to measure the furnace bricks regularly to determine the length of the high-temperature thermocouples

This post was last edited by wang06120325 on 2015-8-26 at 23:07. The tip of the thermocouple is recessed about 50 mm from the surface of the high-chromium bricks; however, during the actual furnace construction process, errors can occur due to the thickness of the refractory ceramic fibers in the gasifier’s wall, as well as in the gaps between alumina hollow spheres and low-chromium bricks, and between low-chromium bricks and high-chromium bricks. When these errors accumulate, the amount of shrinkage becomes less than 50 mm; in principle, it is sufficient to ensure that the thermocouple has a certain degree of shrinkage. During the masonry process, it is essential to ensure the appropriate size of the longitudinal expansion joints for the thermocouples, in order to prevent the bricks in the gasification furnace from being subjected to longitudinal shear forces due to heat, which could damage the thermocouples. The retraction of the thermocouple primarily serves to protect it, but in actual operation, due to prolonged use and severe erosion by the high-chromium bricks, the thermocouple ends up exposed on the outside of these bricks, thereby losing its protective function.

10 mm inward from the surface of the high-chromium brick

It is recommended not to install a uniform depth to facilitate observing the temperature inside the gasification furnace.

Is it appropriate to retract the upper part by 3 CM and the area near the slag outlet by 2 CM?

If it is installed too deep, there is a delay in the thermocouple’s response, which hinders accurate temperature measurement; if it is installed too close, higher requirements are placed on the thermocouple. Agree on different depth distributions

Different depth distributions? Which temperature measured for the furnace should be taken as the standard?

If you can ensure long-term operation, manufacturers with the necessary capabilities recommend installing two sensors: one for use during startup, which can properly indicate the oven temperature; this sensor typically gets damaged within 1 week to 1 month after material is added, with a measured reduction in length of less than 1 cm. The other sensor is intended for use during normal operation, and it is recommended that its length decrease by more than 3 cm according to measurements