Extruder: Equipment Tab

Variable Definitions, Ranges and Default Values

The following table shows the meaning of the variables appearing in this tab, as well as their default values and their generally acceptable range. Note that due to the manner by which the variables are used by the sizing and costing equations, the range of acceptable values may be further reduced.

Variable	Default Value	Range

◙ Screw Diameter The diameter of the screw used for extruding.	0.0 cm	Positive
◙ Max Screw Diameter The maximum screw diameter that a unit of this type is available for purchase in the market.	12.7 cm	Positive
○ Metering Depth The distance between the end part of the screw and the internal extruder walls (gauge).	0.635 cm	Positive
◙ Rated Throughput The total rated mass throughput.	0.0 kg/h	Positive

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Sizing: Design Mode

In design mode, the maximum screw diameter and the metering depth are specified from the equipment tab interface, and the screw angular velocity and the maximum screw angular velocity are specified from the Extrusion: Oper. Conds Tab. The screw diameter is calculated based on the following equation:

eq. (B.3)

where:

● Q is the volumetric throughput,

● α = 0.017684565 is a constant whose value depends on the units of the other variables,

h is the metering depth, and

ω is the screw angular velocity.

If the screw diameter exceeds the maximum screw diameter, the screw angular velocity and the maximum screw angular velocity are calculated based on the cross-sectional area A:

eq. (B.4)

The number of units is then calculated by dividing the maximum screw angular velocity by the calculated screw angular velocity. Using the previous equation, the screw diameter for the maximum cross sectional area is also computed.

Sizing: Rating Mode

In rating mode, the screw diameter, metering depth, number of units, the rated mass throughput and the maximum angular velocity is specified and the screw angular velocity is calculated using eq.B9.

Costing

Equipment purchase cost is based on the screw diameter and material of construction. It is supplied by the built-in model assuming as material of construction SS316.

For more information on this equipment, see Extruder.

For information on the left-hand side variables and options, see Equipment Data Dialog: Equipment tab.