A reliable,
controllable feeder of suitable design and capacity is necessary
for proper operation of a jet mill. All jet mill system packages,
then, are sold with an appropriate feeder, one that is able to
handle the material efficiently and introduce it into the mill
at rates required by the application.
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Feeders |
The feeders recommended
by Jet Pulverizer Co. vary depending on materials and the requirements
of the specific application. Customer requirements in this regard
can vary widely, including provisions for wash-down, explosion-proof
service, allowable metal contact, batch quantity, feed rates, bulk
density, raw particle size, moisture content, flowability, sanitary
service constraints and motor control.
There are three categories of feeder types from which to choose:
Volumetric feeders: feed raw material from a hopper through a helical metering auger. This is the most common method of feeding a jet mill by far. Volumetric feeders are specified with a range of hopper capacities and a range of metering auger sizes. Hoppers usually are designed with some form of agitation to prevent bridging thus assuring steady flow to the auger. Jet mills have performed very well with this type of feeder over a wide variety of raw materials.
Loss-weight feeders: a variant of the volumetric feeder, feature a built-in scale (or other method to measure weight) with a feedback circuit that adjusts metering auger speed (or vibratory level) to match a preset dosage rate on the controller. As the end of a batch nears, auger speed (or vibration) may increase to offset the reduced volume entering the metering auger (or feed trough). These feeders also assure a constant delivery rate of raw material supply without regard to possible varying bulk densities. Powder density may vary between the top to the bottom of a hopper. Loss-weight feeders are easy to adjust to a new powder drop setting. Feed rates are easily converted into common units of measure (ie. pounds per hour, or grams per minute). Finally, process records may be better gathered and stored with computer processor aid.
Vibratory feeders: are the simplest design. They convey raw material along an open vibrating v trough. These feeders draw material from either a simple powder funnel or a stainless steel hopper. Merits of this method include 100% material utilization, inherent suitability for extremely small sample sizes, reduced friction that may cause reaction in temperature sensitive materials, and allows for easy viewing of the feed stock.
Product
Collectors Present Many Options
Product collectors: are engineered to meet demanding dust collection requirements and are integrated into many jet mill packages. Collectors can be simple free hanging “socks” or complex housings with reverse pulse cleaned bag or cartridge filters. These collectors can be designed to strip 99.999% of the ultra fine particulate from the gas stream leaving the MicronMaster® and deposit the product into a container, packager or the next process. Properly designed collector housings provide the following advantages:
- Minimizes the dust explosion risk when processing combustible powders.
- Provides sanitary conditions
- Air pollution control
- Minimizes airborne nuisance dust and asphyxiation risk by venting exhaust gas outside the work environment
- Accumulator for downstream processes
- Increases ease of product recovery and packaging
Jet Pulverizer engineers will specify dust collector features to provide a safe, effective, and efficient system for your material handling requirements.
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