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Sicoma |
PLANETARY MIXERS - FREQUENTLY ASKED QUESTIONS
What is the best type of mixer for my application?
How many Sicoma planetary mixers are there in operation?
How does a full mixer still mix as effectively and fast as a partial batch?
What is the difference between Filling Capacity, Uncompacted Output and Compacted Output?
Why does the Sicoma planetary mixer have a shorter scraper blade tail than others?
Why does Sicoma use Ni-Hard cast-iron liner plates?
Why do we say the gearbox runs cooler?
Do you stock parts in North America?
How do you price your products, is shipping included?
What is the best type of mixer for my application? Regardless of what people have told you, or what you have read, there is a best mixer for each application. Each excels in a different type of concrete:
Twin Shaft - Lots of concrete at high speed, low wear, low maintenance. Designed for rough, tough jobs like dam building and ready-mix. Handles aggregate sizes to several inches. Does not discharge completely, so not good for mixes of different type or color. End of shift cleanout is slow and difficult (unless our high pressure washout system is used). Performance on dry cast mixes is not as good as the best planetary mixers. Gives the highest throughput of concrete in a given floor space, can double plant output without modification to hoppers, scales, belts etc. Most models have single discharge door; exception is Sicoma MAO which has a double door option. "Compulsory mixing" action gives high quality concrete with maximum strength.
Turbine - High quality precast, especially wet cast mixes. Medium speed, medium wear, medium maintenance. Designed for precast. Good cleanout but sensitive to blade adjustment and wear. Good for colored mixes. Simple mechanical system. Easy to install moisture sensors in floor. Up to 4 discharge doors. Most models not fast enough to create "Compulsory mixing", so concrete not as high in quality or strength.
Planetary / countercurrent - Highest quality precast, especially dry cast, block, pavers, architectural. Medium to high speed, medium wear, medium maintenance. Designed for precast, block, pavers. Good cleanout, good for colored mixes. More complex mechanically but best models very reliable. Easy to install moisture sensors in floor. Up to 4 discharge doors. "Compulsory mixing" action gives high quality concrete with maximum strength.
Rotating pan - most of these type mixers are obsolete. Good for precast, both wet and dry cast. Mixing action similar to planetary but mechanically complex, high maintenance. Difficult to install moisture sensors. Single discharge door. Most models not fast enough to create "Compulsory mixing", so concrete not as high in quality or strength.
Drum / tilt up and transit mixing trucks - Slow, poor mixing action takes many revolutions to attain good homogeneity. Critical on charging sequence, requiring initial addition of water to wet blades and help remove deposit from previous batch. Cannot be completely discharged, difficult to clean out and maintain.
Ribbon/Spiral blade - The 'old standard' for precast and block plants. Slow, poor mixing action takes many minutes for good mix. Very little end to end action, so charging method and water entry is critical to avoid variation within discharged batch. Non-compulsory action. Reliable with low maintenance cost. [Top]
How many Sicoma planetary mixers are there in operation? 6000 have been manufactured and there are over 5000 in operation worldwide. No other planetary mixer comes even close to these numbers. In 2006, over 200 have been produced; many more than any other manufacturer.
These statistics show that the MAO is truly what it claims to be - a great mixer for a great price. [Top]
Why does the Sicoma planetary mixer have 3-armed stars while other top mixers in its class have only two? Sicoma's designers have studied the action of both 2-armed and 3-armed stars and concluded that 3 are better. Not only because there are more arms and blades, but because the blades can be positioned to be much more effective. To start with, the arms can sweep the mixing volume more effectively because the more paths there are, the more times each area can be covered in every minute; this is important because the ARMS do the mixing, the blades giving the fast discharge action. This gives better mixing. Less obvious, however, is the angle of the blade. The combined rotation of star and individual blade across the mixer floor shows that the blades should be angled not at right angles to the star shaft but at a slight inward angle. This gives better sweeping action and eliminates lengthways slicing through the mix, which is ineffective and causes excessive wear. Since the outer edge travels further than the inward edge, it receives more wear. While others add replaceable segments to compensate, these must be bought, stored and installed, while Sicoma has simply thickened this outer edge to compensate correctly and give longest life.
Sicoma's blade arrangement is a better design, gives better mixing and lasts longer with less maintenance than any other. Sicoma Strength [Top]
How does a full mixer still mix as effectively and fast as a partial batch? Because in Sicoma mixers, the ARMS do the mixing. They cover from top to bottom and every cubic inch of the mixer volume many times each minute. The angled blades create pressure in front and a void behind, drawing material from the top downward behind each arm and mixing material vertically as well as horizontally. The high speed creates "Compulsory" mixing action, breaking -up clumps and distributing cement evenly to coat all particles. This creates stronger concrete.
Sicoma's mixers can receive AND MIX their full rated volume - and without any extra mixing time. Sicoma Strength [Top]
What is the difference between Filling Capacity, Uncompacted Output and Compacted Output? When the mixer is filled to its DRY FILLING CAPACITY, as the stone, sand and cement mix, the air spaces between stone chunks get filled with sand, and the air spaces around the sand grains get filled with cement. The density goes from about 100 lb/cu. ft. to 150 as it is mixed. Even the spaces around the cement powder get filled – with water. The whole volume reduces by 20% or more as a zero slump mix is made. But this zero slump mix still has lots of air spaces in it. If discharged in this state, you get an UNCOMPACTED YIELD of 20% less than the mixer capacity. When the mix is vibrated in the mould or form, all this extra air is expelled and it compacts by a further 15 to 20% to give the COMPACTED YIELD, which is 2/3 of the dry filling capacity.
What does this mean to the user? It depends on the application:
If the user needs 3” slump or less, the container (Tuckerbilt or bucket) capacity must hold the UNCOMPACTED YIELD.
If the user needs 6” slump or more, the container (Tuckerbilt or bucket) capacity must hold the COMPACTED YIELD.
If the user needs something in between, the container (Tuckerbilt or bucket) capacity must hold something IN BETWEEN. Use your judgment. [Top]
Why does the Sicoma planetary mixer have a shorter scraper blade tail than others? The superior mixing action of Sicoma's blades allows faster and more complete cleanout; it simply does not need a wide scraper tail to clean out efficiently. A larger tail causes dead spots in the mixer which increases the mixing time, or reduces homogeneity of the mix. Another manufacturer's attempt to give fast cleanout is to use a descending scraper blade. This is both unnecessary in Sicoma mixers and elaborate, giving higher maintenance costs in those that use them.
Sicoma's planetary is well designed and simple in concept, reducing future headaches and costs. Sicoma Strength [Top]
Why does Sicoma use Ni-Hard
cast-iron liner plates? Previously the standard liner for Sicoma
and many others was 10 mm Hardox steel plate. This is becoming hard to get
and expensive. Although Ni-Hard is even more expensive, Sicoma has
standardized on this material. Its 600 HB hardness and 15mm thickness give
it 5 to 10 times the wear of Hardox - and it costs you nothing extra.
Wear comparison
for different materials
Another example of Sicoma's commitment to total quality. Sicoma Strength [Top]
Why do we say the gearbox runs cooler? It's a fact that Sicoma's gearbox runs cooler than many others due to its wide, horizontal shape, and as a result lasts longer. Sicoma's reduction gears are designed and manufactured in-house, specifically for the purpose, and run in a horizontal oil bath for perfect lubrication; some manufacturers use commercial reduction gears; the high-speed gears connected to the motor shaft are at the top, where they receive less oil, and are housed in a small bell-shaped cover that does not allow proper ventilation and cooling. The small gears cannot withstand repeated startup under full load and will overheat with prolonged use, destroying the lubricating oils and causing premature breakdown. Sicoma's gears are guaranteed for 5 years/10,000 hours, and that's because we know they are good for it.
Proper design means longer life. Sicoma Strength [Top]
Do you stock parts in North America? A full stock is kept at our North American Headquarters, Montreal Canada, ready for next day delivery across the continent. This stock includes all wear parts and most other parts, including gearboxes, for every model sold in North America, including those sold through our dealers and Mixer Systems Inc. Call us with your model and serial number for prices on any parts that you need.
Can I buy parts on credit? Of course - all it takes is the establishment of a credit account if you don't already have one with us
The customer comes FIRST at Sicoma. Sicoma Strength [Top]
How do you price your products, is shipping included? Some companies price their products in Euros because it is more convenient for them. But you could work out the exchange to Dollars, then find it has changed by the time it is delivered and you end up paying more. Sicoma's policy is to price everything in Dollars; you are guaranteed to pay the price we quoted you, even if the Euro goes up.
Your other unknown when buying European products is the shipping cost. Again, we don't ship FOB our European port for the same reason. You only pay the shipping from the east coast port of entry that is most convenient. We can give you a close estimate for this if you wish.
No hidden costs. Sicoma Strength [Top]
Last updated: July 14, 2007
