Liebherr WKt 4552 GrandCru - Manual (Page 11)

11
Gradient: “Distribution of temperatures within the chamber“
H0 = max (0 -
mj
+U
mj
) – min ( 0 -
mj
-U
mj
)
max = (mean value warmest probe + expanded measurement uncertainty)
min = (mean value coldest probe – expanded measurement uncertainty)
Cabinets are tested empty over a period of 24 hrs including defrost cycles.
Test criteria for characterising the temperature consistency and distribution
1) Gradient or homogeneity: “The gradient H0 is the maximum difference, obtained in an achieved environment, between the mean values of measurements 0
mj
increased by their expanded uncertainty U
mj
, within the working space during the measurement time.”
Example: Gradient (Homogeneity)
The gradient indicates the temperature distribution within the cabinets. Especially in the laboratory sector optimum temperature distribution is crucial to guarantee
the safe storage of samples or other products at any place within the unit. The lower the gradient the better is the temperature distribution within the unit.
Gr
adient H0
LKPv and LGPv laboratory appliances with Profi-Controller
Maximum value
Minimum value
Measurement period