Specific Edge Load Theory

The two parameters that describe the refining process by the specific edge load theory are SEL or intensity of refining and specific refining energy (SRE) and these are defined below. 

SEL = Net Power/Cutting Edge Length (CEL) per second, Ws/m (13.1) Net Power = (Applied Power - Idling Power), kW (13.2) 

Idling load or no-load power is defined as the power drawn by the refiner motor when the refiner plates are widest apart and the refiner motor was running at normal operating rpm with stock flowing through the refiner. It can be measured or calculated. For a double-disc refiner, the idling load can be calculated from Equation (13.3) (Dernier and Silver , 1995)  

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Specific surface load (SSL) theory is an extension of SEL theory and it assumes that the energy is transferred to the fibre bundles during the short edge-to-edge contact phase as well as during the edge-to-surface phase (Lumiainen, 1990). By combining these two, SSL is defined as shown in Equation (13.6), where Equation (13.7) holds ... 

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