KOMAX Plastics Processing

Paraflow Distribution Head

This distribution head was designed to minimize the residence time required for mixing. The low viscosity additive and main polymer follow internal parallel paths. The exit pattern of the additive is like that of the honeycomb of the bee.

The low viscosity additive and main polymer follow internal parallel paths. The exit pattern of the additive is like that of the honeycomb of the bee. This generates an enormous improvement in the A/t value.

In addition, the Paraflow unit gives excellent distribution and dispersion of the additive. It may be shown that the A/t value is given by:

A/t = 8p N/F

This means that if there are N main product holes say, 42 and the additive fraction is 1% then A/t = 106,000.

VISCOSITY AND PRESSURE DROP CONSIDERATIONS

Most polymeric materials are shear sensitive. That is to say, their viscosity is dependent on the shear rate to which they are exposed. Usually an increased shear rate produces a lowering of viscosity and is referred to as shear thinning. Viscosity versus shear rate data is usually provided by the polymer manufacturer in the form of a graph on log/log paper. We list below the shear rate and pressure drop formula for each of the devices we have described and others together with the units involved.

Main pipe inside diameter = D inches
Main product flow rate = Q gpm
Shear rate = g sec^-1Viscosity = m cP
Pressure drop = dP psi
Axial length = L inches
Additive fraction = F
Number of mixing elements = n

Device	A/t Value	Shear rate	Pressure drop	Comments
Open pipe	----------	39.2Q/D³	22.73x10^-6Qm L/D⁴	Hagen-Poiseuille Equation
Helix	np	96.0Q/D³	205x10^-6Qm n/D³	Helix L/D ratio = 1.5:1
KOMAX SYSTEMS, INC. INTRODUCES A NEW STATIC MIXER SYSTEM FOR HIGH VISCOSITY PRODUCTS (U.S. Patent 5,484,203) A Single Injection Point allows pressurized clearing action from the additive pump if needed. The built in check valve prevents back flow of polymer into the additive supply. The PARAFLO Injector *distributes* additive across the inlet of the *ULTRA* mixer. It is less than one pipe diameter in length and has a low pressure drop. The ULTRA Mixer generates multiple interstices with a uniform spatial distribution to give 100% utilization of the mixer volume and superior additive *dispersion* with low pressure drop.


Device	A/t Value	Shear rate	Pressure drop	Comments
L/H unit	8/p² F	215Q/D³	5.9x10^-4Qm /D³	Each hole dia. = 0.45D
H/L unit	3.6/F	81.7Q/Dt²	22.1Qm L/Dt³	Where annulus dia.= 2D/3
SIDD	288/p²F	593Q/D³	12.6x10^-4Qm /D³	Each hole dia. = 0.3D
PARAFLO	8pN/F	Contact factory for shear rate and pressure drop calculations.