Siemens milltronics ILE-37, Instruction Manual

7ML19985CW01

Milltronics ILE-37 – INSTRUCTION MANUAL

Page 15

Linearity 

To test linearity, at least three test weights are used. Each test weight represents a 
different Test Rate. Record the integrator rate display value associated with each test 
weight applied to the flowmeter. 

If all the recorded display values are accurate, the flowmeter measurement is linear. 

e.g. For an E-40 Flowmeter design rate of 12 TPH, the following three test weights could 
be used: 

• 780 g (1.72 lb) = 100% Design Rate = 12.0 TPH 
• 585 g (1.29 lb) = 75% Design Rate = 9.0 TPH 
• 390 g (0.86 lb) = 50% Design Rate = 6.0 TPH 

If non-linear results are obtained, ensure: 

• at no flow, the moving beam does not rest on the zero stop bolt
• at 150% design rate, the moving beam does not reach the full flow stop nut 
• at 150% design rate, the LVDT output does not exceed 1.0 V AC. 
• the damper piston does not touch the damper cylinder wall at any flow rate
• the LVDT core does not touch the inside of the LVDT at any flow rate
• the viscous damper fluid is free of large air bubbles and the fluid level is correct
• the range spring operates in compression from 0 - 100% flow rate
• the sensing head leaf springs are in good condition

If the test weight linearity test is successful, yet actual material test results are non-
linear, ensure there is no air circulation in the housing sensing plate area. If there is no 
significant air circulation in the flowmeter housing while you are running material, the 
material flow pattern is probably non-linear. 

Non-linear material flow patterns can often be corrected by minor modifications to the 
material infeed, or upstream piping. Some integrators are equipped with a linearization 
function to compensate for non-linear material flow patterns. Stand-alone linearizing 
devices are also available for this purpose. 

Electronic linearization should not be used to correct non-linear test weight results.