Lab Mixer / R+D Stirrer

How to Choose the Right Stirrer to Fit Your Mixing Needs?

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What is required to choose a lab mixer or stirrer
What types and power requirements should be considered
How to specify a lab mixer or stirrer
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Choosing the right lab mixer

There is a wide variety of lab mixers on the market. Lab mixers are often referred to as stirrers, blenders, R+D agitators, homogenizers, and benchtop mixer. We will try and break down the many options that may be considered. Depending on the specific features you need for your application, and the economics involved this should help you decide which lab stirrers may be a fit for you.

Classifications
Electric
Electric - explosion proof (XP) for mixing with solvents, flammables, alcohol, etc
Air operated, or pneumatic operated mixer (also good for XP environments)
Hand held mixer (air, electric, or battery operated) "drill" style mixer

The next level of "specialty" mixers can be considered:
High shear lab mixers, or high speed benchtop dispersers
Homogenizers - very high speed and high shear mixers
High shear ultrasonic mixers
High viscosity pale mixers
High viscosity anchor style or planetary mixers, high torque mixers
Drum mixers, tote mixers (getting more into larger volume agitators)
Sealed mixers (for flanged and pressurized tanks)
Biopharm sanitary mixers/agitators - for aseptic and ultraclean mixers
Disposable mixing technology (USP VI bag style mixers)

When dealing with your mixing vendor, it will be very helpful to explain what your mixing application is, and what materials you will be mixing. Depending on the volumes you will blend, and the products being mixed they will be able to help you choose a mixer that would apply.

How to specify a mixer - what information you will need to supply:

a. mixer drive style (how you will power it, typically electric or air operated)
b. mixer shaft and impeller (materials of construction and impeller style)
c. clamp mechanism for mixer to stand, or mixer to tank
d. mixer stand, or mixer vessel type
e. mixer vessel, beaker, drum dimensions - min and max volume you will run
f. do you want a variable speed mixer/disperser for flexibility in processing
g. what is the mixing process and mixing results desired
h. list of ingredients, and the mixture rheology including:

• viscosity (min and max, or describe if changes thru mixing process)
• specific gravity / density
• solids %
• ingredient order of addition
• any unusual behavior or reaction
• temperature
• pressure/vacuum
• is mixture shear sensitive

i. price range
j. delivery timing (do you need a standard stirrer or custom mixer package)
k. some vendors like www.wmprocess.com offer free lab testing of your product to help choose the right mixing technology

	Electric lab mixer/stirrer 110volt 1phase or 220volt 1phase plug in mixer drives. Many mixing impeller styles and sizes are available
	Air operated lab stirrer Mixer drive operated via compressed air.
	Hand held plug in style electric mixer, can also be battery operated. Mixer shown is a high speed high shear homogenizer.
	Drum mixer / tote mixer. Mixer designed for 55gal drums and totes
	Biopharm mixer / sanitary blender. All stainless mixer designed for aseptic mixing and sealed tanks - typical for FDA and cGMP mixing applications. Sanitary electric mixer or stainless air motors are available. Wetted parts are typically 316Lss and would be polished < 20Ra and electropolished, and the agitator would include a GMP documentation package with proper certs.

Definition of explosion proof motor classifications

If you are involved in mixing operations, you need to understand and appreciate the definition of explosion proof motor classifications. Through this article, you are provided with a general overview of definition of explosion proof motor classifications. Armed with this information, you will be in a far better position of making certain that your mixing operations properly are structured so as to ensure the safe operation of the overall system. There are different techniques that you need to undertake depending on what type of mixing actually is occurring within the confines of a particular operation.

There are six general classifications when it comes to the overall definition of explosion proof motor classifications. Again, these brief descriptions can aid and assist you in better understanding how to maintain safety levels of an overall mixing operation.

You do need to keep in mind, when looking at definition of explosion proof motor classifications, that these definitions involve the presence of specific flammable gasses or vapor that may be present in sufficient quantities to produce explosive or ignitable mixtures or situations.

Group C - The definition of explosion proof motor classifications in Group C include certain volatile vapors that when concentrated can lead to explosions.

Group D - The definition of explosion proof motor classifications in Group D involves atmospheres containing gasoline, hexane, benzene, butane, propane, alcohols, acetone, benzol, lacquer solvent vapors, natural gas and the like.

Class 11- The definition of explosion proof motor classifications in Class 11 are those that are hazardous because of the presence of combustible dust.

Group E - The definition of explosion proof motor classifications involve atmospheres containing metal dust, including aluminum, magnesium, or their commercial alloys.

Group F - The definition of explosion proof motor classifications involve atmospheres containing carbon black, charcoal, coal or coke dust.

Group G - The definition of explosion proof motor classifications involve atmospheres containing flour, starch, grain or combustible plastics or chemical dusts.

Of course, when it comes to the pharmaceutical or the food and beverage industries, not all of these definition of explosion proof motor classifications come into play. Moreover, depending upon the ultimate product that will be involved in the mixing process, some of these definition of explosion proof motor classifications will be more important to understand and regulate than will others.

In the final analysis, when it comes to definition of explosion proof motor classifications and dealing with the prevention of explosive situations in the mixing process, two factors come into play. First, the proper type of equipment must be selected and installed -- properly -- in the first instance. Second, it is vital that the equipment once installed be utilized in a proper, appropriate and safe manner.

By understanding definition of explosion proof motor classifications generally, you will be in a better position to make certain that your mixing operations are undertaken with maximum safety.

Air Motors

Known for their rugged construction and reliability, Air Motors and air powered Gearmotors are available in both lubricated and oilless models. An air motor is something to consider for explosion proof applications, or for flexibility in powering a mixer. There are also stainless sanitary air motors which are nicely suited for biopharm mixing applications. Some benefits of air motors on mixing equipment:

• Non-electrical operation reduces the possibility of explosion from igniting flammable gases
• Undamaged by overloads
• Ideal in hazardous and hostile environments
• Rugged and simple to install
• Variable speed capabilities allow flexibility and versatility, by using an air control valve you can easily adjust the mixer speed
• Cool-running operation means air motors can be used in ambient temperatures of up to 250� F (120� C)

There are some negatives with air mixer motors compared to electric mixer motors. The benefits of electric are that they are quiet, do not have excessive air exhaust, and they do have very accurate speed control, and feedback loops to a VFD.