LactoScope Filter
 
Fault Finding
 
Air Lock
Air in the pump is the most common problem on all IR milk analysers. If there is air in the pump it does not generate enough pressure to overcome the homogeniser so the air needs to be let out. The homogenizer can be loosened, while the pump is running (clean cycle). If there is a significant amount of air in the pipework raising the clean and zero tanks can be a help.
Ensure that the small O-ring in the homogenizer does not come loose, it can cause leakages if not fitted correctly.
 
Carry Over
The efficiency with which an old sample (or zero/can liquid) is replaced with the new sample in the cuvette/cell expressed as a percentage. PE > 99% i.e. greater than 99% of what is in the cuvette should be new sample.
 

Purging Efficiency Check
1/
Take 200ml of a homogenised whole milk sample in good condition and 200ml of zero liquid.

2/ Carry out 22 consecutive analyses of water and milk using the sequence water, water, milk, milk, water, water, etc. record the results as per the following example:

 
Sample Number Water Milk
  W1 W2 M1 M2
1 0.00 -0.01 3.48 3.50
2 0.00 -0.02 3.49 3.50
3 0.00 -0.01 3.47 3.48
4 0.00 -0.01 3.49 3.50
5 0.00 -0.02 3.47 3.49
6 0.00 -0.01 3.49 3.50
7 0.00 -0.01 3.47 3.48
8 0.00 -0.02 3.48 3.49
9 0.00 -0.01 3.48 3.50
10 0.00 -0.01 3.49 3.50
Sum W1 = 0.00 W2 = -0.13 M1 = 34.81 M2 = 34.94
Purging Efficiency 34.81 – (-0.13) x 100 = 99.63%
34.94 – (-0.13)

Water to product: (sum M1 - sum W2) *100   Product to water: (sum W1 - sum M2) *100
  (sum M2 - sum W2)     (sum W2 - sum M2)
 
Where:
M1 = first milk reading
M2 = second milk reading
W1 = first water reading
W2 = second water reading
 
Low PE% can be caused by problems with the inlet valve-or milk filter, blockages, a dirty cell or cuvette or problems with the peristaltic pump.
 
Repeatability / Reproducibility
The difference between results of the same sample: Repeatability in general (CV): ≤ 0, 25%.
 

Repeatability Check
1/ Warm a minimum 100ml of un-homogenised whole milk to 40°C and invert gently to mix.

2/ Analyse 10 times using LactoScope repeat function.

3/ LactoScope will report repeatability as a mean and an sd, the sd should be <0.25% of the mean. Causes: Dirty cell/cuvette, Dirty milk filter, Homogeniser, Silica gel

 
Useful Spare Parts
Part Number Description   Part Number Description
SV2 Silica Gel   G000100100 004 O-rings
G000080120 2 x 4 Tubing   G000100110 005 O-rings
G000080100 Bev-a-line Tubing   G000100120 006 O-rings
G000080300 Tygon 2.4 x 5.6 Inlet Tubing   L000032200 Diaphragm
G000090100 Tube Clips   L000091001 Oil Tellus
G000094000 Head Bolts, Pack of 4   LA00033000 Homogeniser
LA00034000 Inlet Valve