Vacuum Tray Dryer
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Vacuum Tray Dryer is used mainly for drying of high grade, temperature and oxygen sensitive products. Vacuum Tray Dryer is highly suitable for drying hygroscopic substances, which are dried to very low residual moisture, content level. Frequently vacuum drying cabinets are the sole possibility for drying lumpy, glutinous products or products of low pomposity.It’s also suitable for drying of thermal sensitive materials easily resolved, polymerized or deteriorated under higher temperature. Sterilization can be conducted prior to the drying process, during which no matter is allowed to enter the product. Static vacuum dryer eliminates the configuration damage of the drying materials, therefore widely used in pharmaceutical, chemicals and foodstuff etc.
SALIENT FEATURES :
Vacuum Tray dryer is the most commonly used batch dryer. They are box-shaped and loaded and unloaded via a door. Inside are several heating plates mounted one above the other on which the product is placed in trays.
The bottoms of both heating plates and trays should be as smooth as possible to permit optimal heat transfer between plates and product.
The medium flowing through the heating plates is water, steam or thermal oil.
The distance between the heating plates is determined primarily by the surface loading and the foaming of the product.
To avoid retrograde condensation the cabinet walls are indirectly preheated by the heating plates. Next, the product is introduced and heated at atmospheric pressure. Only after all individual product trays reach the same temperature the cabinet is evacuated and drying can start.
The preheating phase is very important in order that the drying curve and the foaming of the product is identical throughout the cabinet.
During the main drying phase the vacuum is in the range of 40 to 80 mbar abs and in the final drying phase vacuums of only few mbar abs are reached.
Heating temperatures are normally in the range between 800C and 1100C. Depending on product and surface load, drying takes from a few hours to 1 to 2 days.
For some products the vacuum and temperature profiles are automatically controlled in order to prevent a pass over of the critical product temperature.
The dimensioning of the vacuum system is an important factor in the design of drying cabinet systems. If for example vigorous foaming of the product is desired, evacuation to the operational vacuum level must take place very quickly.
Vapours produced during drying are taken out direct, or via a steam jet compressor to a surface condenser in which the vapours condensate. The non-condensable vapours are extracted by the vacuum system.
On completion of the drying, the product can be cooled by circulating of cooling water through the heating plates.
Often vacuum drying cabinets are supplied to new, small production operations in newly opened markets. Following successful development of the market, it could be worthwhile to replace the cabinets through continuous vacuum belt type dryers.
SALIENT FEATURES - GMP Model :
Main Body/Vacuum chamber SS316 with heavy duty SS316 flange and Stiffeners.
Door SS 316 (Dish Curve shape) with heavy duty SS316 flange.
Shelves Hollow Type pads SS316 with flow Baffles.
Condenser (Shell & tube type) and Receiver (Cylindreical/ Botom Cone type) in SS 304 with Isolation valve and Flow Glass in between to monitor condensation.
Trays (without back folding) in SS316 rounded corners and edges.
Explosion Vent / Rupture Disc on vacuum chamber.
Digital Temperature Controller (FLP) with solenoid controlled Pneumatic operated valve at Hot Water inlet.
Provision for Validation Port on Body
Digital Temp., Indicator (FLP) at H.W. inlet & outlet.
Dial type Vacuum gauge and Digital Temp., Indicator (FLP) in Vapor line.
Pressure release valve in Steam line.
View Glass/Light glass provided on vacuum chamber Door, Body and Receiver.
Silicon transparent gasket for door.
Nitrogen purging valve provided on Vacuum chamber.
Vacuum break valve provided on vacuum chamber
Drain valve for Vacuum chamber and Receiver.
Temperature Accuracy : _+ 2 to 30C
FINISH : Internal 320 Grit Mirror Polish and Outer 180 Grit Mat Finish.
OPTIONALS :
Condenser and Receiver in SS 316 instead of SS304.
Limpet coil on Vacuum chamber.
Limpet coil on Vacuum chamber.
Hot water system (Steam heated) with tank (Insulated), SS304 Steam Radiator/Electrical heaters, Circulation pump with FLP Motor and controls.
Insulation on the vacuum chamber outer surface (with / without ) door. The insulation is enclosed and covered with SS 304 sheet & polished to matt finish.