For many manufacturers, ‘mixing’ is the crucial stage most influential to the final product.

Food, pharmaceuticals, coatings, chemicals and virtually all fluid industry are in constant and progressive development. As innovative changes take place within the coatings industry, the mixing industry advances with innovative design and technology. It is essential to monitor new developments in the portable mixing market in addition to keeping up with the transformations of coatings technology.

The size of the industrial mixer market is challenging to deduce. JBW Systems had a market study done by John D. Pace, P.E., retired president of the American Coating Association, titled “Industrial Mixer Market Analysis – Focus:  Portable Mixing Units”. By methodically researching publicly owned mixer manufacturers, data gathered from various industrial mixer manufacturers, internet research and other available methods, Pace concluded that the portable mixer market can be estimated conservatively from $600 million to an optimistic $900 million. Please note this research was done in 2000, and the mixer market has exploded since that time.

There are virtually hundreds of mixer manufacturers around the world, and each may market dozens of different mixers. Out of these, about 10 make up 55% to 60% of sales the mixer market. Smaller mixer manufacturers make up the difference; some are small, private companies and others are buried deep within corporate conglomerates. From a global perspective, the portable industrial market can be as intimidating as the customer’s base, demanding better agitation for new, improved products.

Blending, Mixing and Agitation

Many manufacturers, such as those in the food, paint, cosmetics, chemicals and other fluid industries are completely dependent on the mixing industry and mixing technology. The basic purpose of mixing is to combine two or more materials and create uniform and exact results (the product); each production run must result in consistent properties, such as: texture, weight, size of particles, volume, molecular distribution, heat, color, etc. Although blending, mixing and agitation are terms used interchangeably, blending is a gentler process combining two or more solids into a perfectly blended state, sometimes adding a small amount of fluid into the product (blending flours to make dough). Both the terms “mixing” and “agitation” imply a more powerful movement to unify two or more fluids into a homogeneous state; often with the addition of a concentration of fine solids/particles (metal flakes in paint).

Importance of Mixing Technology

For many manufacturers, ‘mixing’ is the crucial stage most influential to the final product. New mixing technologies can guarantee shorter production time, lower operational costs, combine dispensing equipment with mixing, preserve government regulations (EPA, OCSHA, etc.), affect energy usage and waste treatment, be readily moved to the next batch, and, many other personalized options.

Industrial mixers are used in processing adhesives, chemicals, cosmetics, food and beverages, coatings, paper and pulp, plastics, pharmaceuticals, and waste/water treatments. The food, pharmaceuticals and cosmetics industries require mixers that adhere to strict sanitary conditions. Chemical, pharmaceuticals and some polymers need a mixer with a coated interior surface for pure, non-stick and acidic processes. All these industries require meticulous mixing, blending and/or agitation. Improper mixing may affect cost, profit, overtime and the amount of substandard or scrapped products (materials that do not cure, air voids on surface, sticky surface, soft spots, softening at elevated temperatures, changes in chemical or electrical resistance, craters, fish eyes, cracking or weakening of the product) and many other undesirable side effects.

A 2004 article; “Masterminding Mixing Technology,” by Rita D’Aquino indicates that although mixing is an essential step in chemical processing, it also significantly influences the manufacturers income. D’Aquino refers to an ‘industrial mixing handbook’ that estimates the cost of poor mixing to be $100 million annually in the United States alone. Mixing equipment can no longer be considered an inconsequential component in production; not when faced with rising costs of energy and raw materials, government regulations, taxes and other demands of industry. Mixing performance is crucial for improved, consistent products with exact standards. Any component that gives one a competitive edge is crucial.

Types of Industrial Mixing

Some industries use ‘batch’ mixing, which is normally a very simple process. Materials are added to a container; the batch is mixed completely, afterward the product is sent to a different stage of production. When finished with the current batch, the mixer is made ready for the next batch, either right away or days later. The other form of mixing is ‘continuous’ when the container continuously has material added to it and the fluid is agitated continuously and the end product is taken out or discharged. A continuous mixer runs for long periods of time and is used for mixtures that thicken or solidify upon dormant periods.

Organizing the hundreds of mixers can be daunting, and depending on each individual source has conflicting types of mixers. Basically there are four categories:

Blenders: These are made to blend bulk solids with other solids; in sub-classes below:

• Convective blenders: paddle blender, ribbon blender and vertical screw blender. Transfers heat by movement.



• Tumbler blenders: double-cone blender, V-shape-blender, and slant-blender. Uses upstream or down stream air to blend.



• Fluidization blenders: plow mixer, double paddle mixer. Moves solids as if they were liquids.
  
  

Agitators: Mix fluids with other fluids, sometimes dispersing gases into liquids, heat transfer, and suspension of solids in liquids by using rotating impellers, classed as follows:

• Axial flow impellers: These impellers are angled less than 90 degrees, creating a flow parallel to the impeller shaft. (examples are boat propellers and pitched-blade turbine).


• Radial flow impellers: This type of impeller blade discharges the flow along the impeller radius in very distinct patterns. The blades are parallel to the axis of the impeller (examples are paddle, flat-blade turbine and anchor).

Heavy-Duty Mixers (high-viscosity mixers): These mixers are used for paste-type and viscous material (adhesives, gums, resins, putty, dough, etc.) and adapt to materials with variable viscosity changes. They include the following:

 
• Double arm mixers
 
 
• Dual- and triple-shaft mixers
 
 
• Planetary mixers: use two mixing blades rotating around separate shafts with the two blades also rotating around a center axis. This creates an inner-mix and shearing of the material.
 

Portable Industrial Mixers: This type of mixer is diverse and offers unique and individualistic mixing methods to keep up with the challenges of the changing coatings industry. Portable mixers are downsized and used in laboratories, in R&D, and up-scaled for use in major production. Portable mixers are used most commonly in drum containers and Tote® tanks (IBC).

There are three different types of impellers used on industrial portable mixers: propellers, paddles and turbine impellers. Propellers are like props used on out-board motors. Paddles are usually flat, immovable blades fitted along the full length of a shaft. A turbine impeller is conical with multi-blades welded – this type of impeller normally is fitted on a shaft and is centered over the drum.

Determining which mixer to purchase can seem overwhelming even for process engineers, many times purchasing simply orders from the same manufacturer without checking the unique and innovative modern mixers. When distinguishing between the various mixing designs some of the following considerations should be considered:

• Size of container


• Viscosity of product


• Flow conditions


• Projected end result


• Motor power and speed (air or electric driven)


• Production time


• Cross-contamination/leakage


• Closed or open container


• Probability of sheer


• Air entrapment


• Stationary mixer or portable


• Custom-made for unique tank and/or product


• Price and Delivery

Mixing Equipment Associations/Groups

Most industries have an association that promotes marketing for that particular industry. Industrial processing of liquids and solids traverse the globe, offering diverse and unique products and mixing technologies that serve these many divergent markets. Nevertheless, the mixing industry does not have an association dedicated to the growth of the industrial mixing market (at the present time). There are, however, several groups associated with the mixing industry that focus on the technical aspect of mixing instead of sales and marketing of mixers.

North American Mixing Forum (NAMF) has a mission to provide an open forum for mixing technology. It offers a blend of academic and industrial mixing experience and provides dialogue for specialist in fluid mechanics and mixing. Every two years the forum assembles. NAMF has a web site at www.mixing.net and offers books on mixing technology, a consultant list, mixing vendors and other services.

American Institute of Chemical Engineers (AIChE) is affiliated with NAMF and was founded in 1908 when a group of chemical engineers formed a professional society to promote and improve chemical engineering. This group is the principal chemical engineering professional society in the United States with 57,000 plus members. For more information visit their web site at www.aiche.org

European Mixing Network (MixNet) is located in Bedfordshire, Great Britain. Its mission is to bring together European academics and industrialists who are interested in exploring mixing issues. These issues can be related to general mixing, computational fluid dynamics and chemical reactions during the mixing process.

Fluid Mixing Process (FMP) is driven by industry and is a mixing research and design project. It is managed by BHR Group Limited (also in Bedfordshire, Great Britain). It is funded and guided by industrial members. FMP reviews public information and other relevant data and examines in-line, jet mixed systems, mixing in stirred tanks, scales, rheologies, and geometrics.

The demand for improved industrial mixers will continue along with each new and unique product that requires mixing. Process engineers are forced to keep-up with unique mixing products as the evolution of mixers continues progressively forward. Production managers should be explicit with their requisition of mixing equipment, otherwise purchasing may simply order the same-old product. State-of-the-art mixers can be cost-effective, interchangeable, portable, and aid industry in government regulations. There are better ways to cut costs then simply settling on old or non-productive mixing equipment.

For more information, visit www.jbwsystems.com.