Stabilized Base Mixers offer many benefits for construction aggregate production because they are designed to create a superior blend of base material.
When properly fed, these units provide effective blending and optimum uniform moisture content through spray bars mounted over the tub near the feed end for quicker compaction when spread by a road contractor.
Intermeshing corrugated face paddles on twin rotating shafts provide a far more thorough mixing action than simply mixing materials "in place" on the right of way. The mixer shafts rotate in opposite directions, and the paddles intermesh and rotate into each other with an upward motion toward the center of the mixer.
The paddle action produces a thorough blending of the material, which at the same time progresses slowly forward in the machine to the discharge opening at the end of the mixer.
Tips to optimize your Stabilized Base Mixer
Keeping your Stabilized Base Mixer running efficiently is important for both production and return on investment.
Follow these tips to ensure your Stabilized Base Mixer stays in peak operating condition.
1. Feed it the right size material
Stabilized Base Mixers are designed to blend granular products with stabilizing additives, such as clay, cement, water, calcium chloride, emulsified asphalt or other materials. They are not designed to break down large lumps. Because of this, only properly sized materials should be fed into the unit.
What is the right size to feed the mixer? It depends on the mixer itself.
Stabilized Base Mixers are offered in different sizes, measured by the diameter of the paddle shafts. Each can handle a different material size.
For example, a 27" diameter machine can handle material with a maximum size of 2". The 36" and 44" diameter machines can handle material with a maximum size of 2.5".
To prevent damage to the Stabilized Base Mixer, the feed material should be pre-screened to remove oversize before it enters the machine. Please note that some manufacturers' warranties may be voided if oversize material is fed to the machine, so pre-screening is doubly important.
2. Feed it correctly
Not only is the size of the feed important, but the way the material is fed to the machine is key to creating quality base material as well.
The material feed chute should be positioned to feed centrally between the mixer shafts. It should drop the material into the mixer between 12" and 18" from the back plate of the machine. From there, the feed source should be continuous to achieve consistent mixing results.
3. Operate it as designed
Operating Stabilized Base Mixers as they were designed/intended is another way to ensure optimum performance.
The speed of the mixer shafts is set at the factory to suit the application. It is generally not recommended that the speed of the rotating shafts be varied to change the mixing characteristics.
If you want to increase the mixing action of the machine, you can reverse some of the paddle blades. Right-hand blades can be installed on the left-hand shaft and vice versa. This will increase the retention time and the mixing action, providing even more thorough mixing.
However, reversing the paddles will reduce the capacity of the machine, and the power requirements will be increased.
If you decide increased retention time is more important than a reduction in capacity, be sure to check the motor's power draw to be sure it is not overloading.
Degree of installation/operation
Stabilized Base Mixers are designed and intended for horizontal installation and operation. This provides optimum performance. Anything other than a zero degree installation can potentially bog down the machine and/or create excessive amperage draws.
If an increased residence time is required to provide more mixing time, try reversing the paddles.
4. Follow a routine maintenance schedule
Routine maintenance is key to optimum operation. Periodic inspections can help identify issues before they turn into costly breakdowns.
For Stabilized Base Mixers, periodic inspections should begin after the first day of operation. During this inspection:
- Check the paddle bolts for tightness
- Check components that are subject to heavy vibration or shock loading, such as the paddles
Other routine service checks and adjustments that should be made include:
- Checking the V-belt drive for proper belt tension and for worn or frayed belts
- Checking the outboard bearing vent opening relief slot for evidence of water leakage caused primarily by a leaky shaft seal
- Checking the mixer shaft wear paddles for damage or breakage that would reduce operating efficiencies
- Checking for loose bolts on the machine, supports, drive, wear shoes, shaft drive coupling, etc. possibly caused by vibration transmitted from other equipment
- Checking the gear reducer for oil level and checking the shaft seals for signs of leakage
If you need to replace paddles or coupling parts, or if you need to perform maintenance to machine, lock out and tag out the power to the Stabilized Base Mixer before doing any service work. This will prevent the machine from being started while anyone is in the machine.
5. Keep spare parts readily available
It is recommended that you keep certain spare parts at your facility so that you can perform any needed repairs discovered as a result of your routine maintenance inspections.
For Stabilized Base Mixers, you should keep the following spare parts:
- Paddle spuds
- Right-hand paddles
- Left-hand paddles
Keeping a supply of spare parts ensures a speedy repair process, as you don't have to wait for parts to ship.
Once you remove a spare part from your shelf, be sure to replace it so you will be prepared for any future repairs.
6. Consider optional add-ons
Optional equipment is available to help process more difficult materials.
Consider investing in curved close-clearance liner plates for processing binding materials. These replaceable abrasion-resistant liners provide close clearance of the tub bottom to the rotating mixer paddles when processing binding additives such as Portland cement or emulsified asphalts.
Making the most of your machine
To achieve more ROI from your Stabilized Base Mixer, it is important that you feed the machine correctly and with the appropriate particle size at a controlled, regulated feed rate. You should operate it as designed and make inspections a part of your daily maintenance routine.