Dynamic Pressure Transducer Calibration in Multi Chamber High Temperature Jet Vessels
Dynamic pressure transducer calibration in jet vessels demands thermal sweep profiling to prevent inter-chamber flow imbalance and fabric unlevelness.
Thermal Hysteresis
Thermal Lag
Measurement errors occur when an instrument displays different values at the same temperature depending on whether the temperature is increasing or decreasing. In the temperature sensors used in high-temperature dyeing autoclaves, thermal hysteresis causes discrepancies in the readings during the heating and cooling phases of the cycle. This divergence occurs because the sensor materials retain thermal energy, preventing the electrical resistance from returning to its baseline at the same rate during cooling.
Material Response
The internal stress in the sensor substrate changes depending on the direction of the temperature transition. When a dyeing cycle shifts from a heating phase to a cooling phase, the sensor registers a slightly higher temperature than the actual liquor value. This error can result in premature enzyme addition or incorrect dye fixation, affecting the final quality of the treated fabric.
Calibration Strategy
Compensating for this error requires the use of dual-direction calibration curves in the control software. This digital correction adjusts the sensor output based on the direction of temperature change, ensuring that the process controller receives accurate temperature data throughout the entire cycle.
Sensor Choice
Selecting high-quality platinum resistance thermometers reduces this thermal lag, ensuring stable control of textile treatment baths.