Industrial Pharmacy Department

4th Year Faculty of Pharmacy

Alexandria University

Fall 2010

Introduction for Mixing:

What's meant by Mixing?

It's the process in which two or more than two components in a separate or roughly mixed condition are treated in such a way so that each particle of any one ingredient lies as nearly as possible to the adjacent particles of other ingredients or components.

This process may involve the mixing of gases, liquids or solids in any possible combination.

Mixing of a gas with another gas, mixing of miscible low viscosity liquids and mixing of a highly soluble solid with a low viscosity liquid to effect dissolution are relatively simple as compared to the mixing of gases with liquids, mixing of liquids of high viscosity though miscible, mixing of two immiscible liquids such as aqueous and oily solutions to form emulsions, mixing of solids with liquids when the proportion of solids is high and mixing of solids with solids, specialized equipments are required for these operations.

Some of the examples of large scale mixing practiced in pharmacy :

Mixing of powders in varying proportions prior to granulation or tabletting.

Dry mixing of the materials for direct compression in tablets.

Dry blending of powders in capsules and compound powders (Insufflations).

Blending of powders in cosmetics in the preparation of face powders, tooth powders.

Dissolution of soluble solids in viscous liquids for dispensing in soft capsules and in the preparation of syrups.

Mixing of two immiscible liquids for preparation of emulsions.

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Mixing of semi-solids

Introduction:

The mechanisms involved in mixing semi solids depend on the character of the material which may show considerable variation.

Many semi solids form neutral mixtures having no tendency to segregate although sedimentation may occur.

The most commonly used semi solid mixers are:

1- Sigma blade mixer

(Also known as Double Arm Mixers and Kneader Mixers)

Double Arm Sigma Blade Mixers are engineered specifically for kneading, mixing, and homogenizing wet, pasty, and highly viscous products.

The two Double Arm Sigma shaped blades, which sit horizontally and parallel at the bottom of the mixing trough, provide thorough mixing.

The blades rotate at different speeds in opposite directions causing the product to be transferred from blade to blade and from end to end, resulting in a figure eight pattern.

The mixing trough can be tilted up and forward through the use of a hydraulic system. Valves can be located in the bottom of the unit, allowing the product to discharge through plug, ball, or "bomb bay" type valves.

A third method, which has several advantages, is the use of an extrusion screw to discharge the product in a form or shape, or directly to the next phase of processing.

Options of the mixer:

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Mechanical or hydraulic drive system

Jacketed mixing troughs or heating and cooling

Designed for pressure, vacuum, or inert gas operation

Remote operator control.

Specialized die heads / special extrusion spouts.

Automated operation of cover via hydraulic piston.

Cored blades of various design.

LABORATORY DOUBLE ARM SIGMA BLADE MIXERS

Laboratory Mixers are available in sizes ranging from 1/4 gallon to 3 gallon working capacity.

Variable speed drive on the blades standard. Stainless steel construction standard, jacketed is standard.

Applications of the Mixer:

Ideal for mixing, kneading of highly viscous mass,

sticky and dough like products.

Mixing of pastes, rubber, and heavy plastic masses.

Applications in Food, Rubber, Pharmaceutical and Chemical industries.

Dry powder to wet phase mixing.

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Triple-roller mill

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(Also named as: Three roll mill)

Applications of the Mixer:

Three roll mills are widely used to mix electronic thick film inks, high performance ceramics, cosmetics, plastisols, carbon/graphite, paints, printing inks, pharmaceuticals, chemicals, glass coatings, dental composites, pigment, coatings, adhesives, sealants, and foods.

With the recent development in technology, they are also utilized in the production of cable cover, electronics, soap, and artificial plastics.

Small bench models are used for bench-top development work, laboratory work, and low volume production.

Larger bench and floor models are built to meet different production needs from pilot plants to large volume productions.

How Three Roll Mill Works?

A Triple Roll Mill is a machine that uses the shear force

created by three horizontally positioned rolls

rotating at opposite directions and different speeds

relative to each other to mix, refine, disperse, or

homogenize viscous materials fed into it.

The pasty substance is fed into the hoper, where it is drawn between the feed and center rollers.

When pre-dispersed, the substance sticks to the bottom of the center roller, which transports it into the second gap.

In this gap the paste is dispersed to the desired degree of fineness.

The scraper system removes the finished product from the apron roller.

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روان حسين طلعت عبد اللطيف موصلى 44577 روان فاروق خليل محمد شحاتة المغربى 44578 روان مجدى احمد شلبى 44579 روان محمد احمد على احمد 44580 روان محمد محمود بكور 44581 روايدا احمد احمد محمد صالح 44582 روشان خليل علي خليل 44583 سعيد غطاس ريتا رفعت 44584 ريتا لويس نجيب بولس 44585 ريجى عادل عطا الله بسخرون 44586 ريم إبراهيم أحمد محمد ابوسليمان 44587 ريم شريف محمد محمود الشنديدى 44588 ريم عبد الرحيم محمد عالم 44589 ريم على حسن على الحداد 44590 ريم محمد نصار احمد العادلى 44591 ريم هشام محمد رضوان على 44592 بديع جرجس غطاس ريمونده 44593 ريهام السيد رضا محمد شوقى محمود سعد 44594 انور احمد محمد المعداوى ريهام 44595 ريهام رافت الياس فارس 44596 السيد الرامخ ريهام رضا حسن 44597 ريهام شكرى ابراهيم ابراهيم كبشه 44598 محمد العسيلى ريهام طه على 44599 ريهام عبد الله السيد عفيفى عفيفى 44600

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