The Solid Loss Factor SLR causes a loss of material velocity by friction.

A material friction equal to zero causes a velocity loss of zero.

An increasing material friction equal to zero causes an increasing velocity loss.

The increasing velocity loss is compensated by an increasing driving force on the particle.

The acceleration force on a particle is given by: Acceleration force = (drag force – friction force) = mass flow * d(material velocity)

This formula already indicates that an increasing friction force causes a lower acceleration force.

When:

drag force <= friction force then d(material velocity) = 0 or negative

If d(material velocity) = 0 or negative, then the particle will not be accelerated but decelerated and the material velocity will be 0 or negative.

With a material velocity, which is 0 or negative the conveying pipeline is choked.

Where the drag force is given by: Acceleration force = (drag force – friction force) = mass flow * d(material velocity)

-the drag force is dependent of:

ogas density

orelative particle velocity = (gas velocity – particle velocity)

-friction force is dependent of SLF.

-d(material velocity) is dependent of (drag force – friction force).

The conclusion is that a high SLF can lead to choking of a pneumatic conveying installation.

(Think of sticky and wet material, having a high SLF)

This equation can only be solved by numerical integration,

This numerical (2-step) integration is taken care of in the pneumatic conveying calculation algorithm. ■