# Inline Drying Rate (dM/dθ) SoftSensing & Control System

The drying rate (dM/dθ) for a product being dried can be sensed and controlled inline by relating it to the process variable (∆T). This relationship is obtained by taking the first derivative of MC with respect to time (θ) of the Delta T model (equation (1) to give the drying rate in a dryer, oven, kiln, or the like, in terms of (∆T) shown in equation (2).

**MC = K _{1}(ΔT)^{p} – (K_{2}/S^{q})** (1)

**(dMC/dθ = K _{3}(dΔT)/(dθ)** (2)

Since drying rate is related to the rate of change in (∆T), with respect to time, it follows that the drying rate of a product being dried, baked, coated, etc., can be continuously sensed and controlled simply by use of the (∆T) process parameter. One possible use for the sensor is in the baking industry. For example, a 3-N-1 sensor combining MC, drying rate, and surface temperature could be monitored and controlled using one common process parameter (∆T). Other possible applications would be in coating, curing, and laminating various products.