Material Handling

Why Use a Team Colloidal Mixer?

The “Rolls Royce of Mixers” - the high shear colloidal mixer, as used by Team Mixing Technologies, is the leading colloidal mixer in the industry, recommended by most grouting experts world-wide.

High-shear colloidal mixers are internationally recognized as the most efficient method of mixing cement-based grouts and other materials. Colloidal mixing results in very stable mixes which resist bleed and water contamination.

Rapid mixing of grouts containing sand, up to a sand/cement ratio of 4:1 and neat cement grouts, with water/cement ratios as low as 0.36:1 without additives. Ratios may be even lower with the addition of plasticizers or super-plasticizers.

Team colloidal mixers are very efficient at mixing bentonite and other clay products. The mixing process accelerates hydration and produces a more stable, homogenous product.

Advantages of Team Colloidal Mixers

• Cost savings: The highly efficient mixing action allows for reductions in the cement content for a given strength. UCS testing of two-component grout samples has indicated that strengths are virtually doubled for a given mix recipe as compared to simple paddle mixing.
• Optimum mixing: Slurry is repeatedly re-circulated through the zone of high shear within the colloidal mill. This breaks down the clusters of dry particles (agglomerates) and ensures maximum dispersion of fluids and solids.
• Speed: The vortex action within the mixing chamber rapidly assimilates solids into the high shear mill, resulting in very rapid batch times. Also, as mixing occurs during the entire weigh cycle, actual mix cycle times are minimized.

• Pressure discharge: The pumping action of the mixer enables rapid transfer of the mixed slurry directly to the agitation tank or final destination.
• Compact footprint: The mixer also serves as a scale and pump, eliminating other equipment.
• Automated self-cleaning option: Team's unique design ensures the mixer and lines are cleaned after every discharge cycle and the subsequent wash water is recycled. No additional waste water is generated during normal production cycles.
• Reliability: The combination of robust design, very few moving parts, auto-lubrication, and readily availability of spare parts ensures long life and reliability for the equipment.

Description of Colloidal Mixing

Colloidal Mill: The key element of the colloidal mixer is the colloidal mill which houses a high speed rotor (discar) operating at 2100 rpm within a close-fitting chamber housing. The clearance between the discar and the walls is approximately 3 mm (1/8”). Here, a high turbulence and shearing action is created capable of breaking down clusters of dry cement particles (agglomerates).

The colloidal mill also acts as a centrifugal pump and will discharge slurry into an agitation tank. The colloidal mill is capable of generating a maximum discharge pressure of 200 kPa (30 psi) and a flow rate of up to 750 l/min (200 gpm). It is possible to increase the mills efficiency as a pump (thus giving it a higher pressure capacity) but this reduces its efficiency as a mixer. This lower pump efficiency translates into a higher energy input. Depending on the required batch size, one to four colloidal mills may be incorporated into the mixer, each requiring a 22 kW (30 hp) electric motor.

Mixing Tank: The mixing tank acts as a centrifugal separator spinning the unmixed, thicker grout towards the outside of the tank while the lighter portions of the mix move inwards, towards the throat of the tank and into the colloidal mill. Once through the mill, this lighter material is discharged tangentially into the vortex, blending with the unmixed material. Several passes through the mill produces a homogenous mixture. The entire mix cycle, once all materials are added, can take as little as 15 seconds.

Control Valves: The output from the colloidal mill is sent into one of two paths. Slurry is either directed tangentially back into the mixing chamber (mix cycle), creating the vortex action, or it is directed to the agitation tank or truck (discharge cycle). Pneumatic or manual pinch valves are used to divert slurry flow.

Self Cleaning: After a batch is discharged the mixer is refilled with water. This water is directed through a standpipe in the mixer tank to a spray nozzle which scours the inside of the mixer clean. This water remains in the mixer and is used in subsequent batches.

Comparison of Team Colloidal Mixers vs. Competitive Units

Don’t be fooled – all colloidal grout mixers are not alike. Team Mixing Technologies’ colloidal mixer utilizes a “true colloidal mill” that shears the cement particles. Other competitors use a centrifugal pump to simulate the shearing action which in reality, serves as a recirculation pump without the high-shear mixing action.

Each Team colloidal mill has two large 200 mm (8”) open throats coupled directly to the feed box, allowing full flow, enabling thicker mixes and allowing easier access for cleaning. Competitors utilizing a centrifugal pump have a small inlet connection, usually 75 to 100 mm, (3 to 4”), causing restrictions and potential cavitation problems with heavier mixes.

The discharge velocity of Team’s colloidal mills combined with the tangential inlets on the mixing vessel allows a high velocity vortex to be created resulting in superior mixing. Competitors often need the assistance of a secondary paddle-style mixer to produce a sufficient vortex for mixing.

Generally, Team’s colloidal mills require more power than the competitors – up to 22 kW (30 hp) per mill. Power utilized is directly proportional to the shear rate, hence the more power added the more shearing and the more rapid the mixing cycle.

Colloidal Mixer Prepared Grout Homogenous No cement agglomerates Maximum hydration Maximum strength Minimal grout bleed Paddle Mixer Prepared Grout Non-homogenous Many agglomerates Incomplete hydration of cement particles within agglomerates Lower strength Bleeding in grout lines