M501 LABORATORY FLUID BED DRYER & DYNAMIC MOISTURE ANALYZER
The Sherwood Scientific Laboratory Fluid Bed Dryer can be programmed via a computer interface to step through an unlimited number of drying stages having the following parameters defined, controlled, and monitored:
Inlet air temperature
Blower motor speed
Pulse flow function (for difficult to fluidise samples)
Without a computer interface the programmable dryer can run one stored program of up to 18 steps, or can be used as a conventional dryer.
Additional features of this advanced in-lab dryer technology include: Precise air flow control, and membrane sealed controls to prevent ingress of particles into the instrument.
SHERWOOD M501 ADVANCED LABORATORY FLUID BED DRYER
AUTOMATED MOISTURE ANALYSIS
Unique dynamic moisture analysis software graphs the moisture curve while drying, including the critical moisture point where bound moisture is driven off.
Dries up to 5 kg of wet solid (up to 80% mosture content, in 15 min
High air flow rate ensures rapid moisture removal at relatively low temperatures
Thorough mixing assures no wet spots remain in sample
Air cushion between particles reduces abrasion so that particle size is not altered
Can be programmed for a known moisture content, or to remove only surface moisture.(Great for tablets)
If water is added to a dry particulate sample, it is preferentially absorbed within each particle until saturation is reached., following which the moisture that is held is external to the particle.
Drying essentially reverses this process, and similarly occurs in two stages, initially removing external moisture before reducing the moisture content within the sample.
The Stage1 external moisture content removal occurs at a constant rate, depending on dryer parameters of air temperature and flow rate. The particles have very little influence on this moisture removal.
The,"Critical Moisture Point" is the point where Stage 2 begins, and the moisture from within the particle is removed. Stage 2 drying is not directly influenced by the flow rate or temperature of the air. To change the speed of Stage 2 Drying, one must reduce particle size, add alcohol, or chemically modify the particle to effect it's affinity to water.
A drying curve is generated by measuring a samples weight loss over a period of time. The slope (rate of drying) is constant until the critical moisture point is reached.
Once the rate changes, moisture has begun to diffuse out of the particle.
H 19.7 " x W 16.9" x D 33.1"
WEIGHT 53.9 lbs
MINIMUM PARTICLE SIZE 5 MICRONS
SELECTION OF AN APPROPRIATE FILTER IS BASED ON THE PARTICLE SIZE DISTRIBUTION OF THE SAMPLE, AND THE FLOW RATE REQUIREMENTS TO DRY THE SAMPLE
FILTER BAGS ARE AVAILABLE WITH A TOP CAP, OR AS A SLIP ON, WHICH PROVIDES THE QUICKEST DRYING TIME, BECAUSE OF THE LARGER SURFACE AREA, AS COMPARED TO A FLAT MESH SCREEN.
SAMPLES WITH PARTICLES BELOW 45 MICRONS, OR WITH A WIDE BI-MODAL DISTRIBUTION, GENERALLY WORK BETTER WITH A SEALED (TOP CAP)SYSTEM. SOME SAMPLE LOSS MAY OCCUR IF A FILTER BAG IS EMPLOYED.
THE INLET FILTER, AND OUTLET FILTERS IN A TOP CAP ASSEMBLY, ARE GENERALLY THE SAME SIZE, BUT THE OUTLET FILTER SIZE, OR USE OF A FILTER BAG, ARE MOSTLY DEPENDENT ON THE AIR FLOW REQUIREMENTS, AS DICTATED BY THE SAMPLES FLUIDIZATION CHARACTERISTICS.
(If the sample fluidizes near the base of the tub, a larger aperture top cap filter, or filter bag, will allow for more air flow, and subsequently quicker drying)
Drying tubs are made in either stainless steel, or glass, in 5 liter, 2 liter, and 250 ml (MINI-TUB), capacities. Up to 4 mini-tubs may be used, at a time, using the special mini tub holder. See SPECIAL TUBS, for more information on mini tubs, low density classifier tubs, and sieve drying attachments.
Glass tubs allow the user to see the sample drying, which can make it easier to achieve optimal fluidization characteristics with the sample. Stainless steel tubs offer extended durability.
Tub selections should be made based on three times the volume of the initial sample. The wet sample should occupy 1/3rd of the tub, and should dry to approximately 1/2 of the tubs volume.Samples with high moisture content are allowable, but not slurries with free water.