Construction and main components of the whole system

Construction and main components of the whole system

1. Drying chamber

The chamber,where freeze drying process occurred, is cylinder shaped with multiplereinforcing ribs to strength. The chamber, doors are constructed in sUS304 stainlesssteel.The chamber contains both the product shelves and the vapour condenser in side.The chamber is fitted with valves of vacuum line connection, drain, water defrost andvacuum release. The chamber has two doors - one at each end. The one is for productsloading / unloading; the other is at the condenser end. The doors and chambers aresealed by silicon rubber to avoid any vacuum leaks. The doors have an opening angleof 110.The hinges will be either left or right hand side, to be specified by thecustomer.Closing is by means of four quick acting latches. Each door has viewingport. The frame of viewing ports is made of 304 stainless stecl and toughened glasswindow, to allow visual monitoring of both the vapour condenser and product.Trackis suspended on the ceiling of inside the chamber to allow trolleys hang and move.

2. Shelf and trolley

A particular number of modules are consisting of a number of shelves on where areavailable for product loading, with the top plate providing radiant heat only.

The product is placed in trays, which are loaded onto the heat-plates (shelves) in thefreeze dryer. The heat-plates can be chilled and heated, so the machine is capable offreezing product in place or pre-frozen in IQF. The heat-plates are fabricated bysUS304 stainless steel or aluminum, and have a flat upper side and heating fluidchannels on the underside. The trolleys of large scaled lyophilizers are fitted withwheels that run in a track located above the chamber, allowing each trolley to bewheeled outside of the chamber.

3.Product trays

A: The SUS304 stainless steel product trays are designed for freeze dryer to processliquid material mainly. Two sets of trays are included with the freeze dryer.

B: The aluminum product trays are designed for freeze dryer to process solid materialmainly, and have rounded corners for ease of cleaning.Two sets of trays are includedwith the freeze dryer.

4. Vapour condenser

The vapour condenser is located in the rear half of the chamber or lower half, and isconstructed from sUS304,25mm round tube.Refrigeration of the vapour condenser isby direct expansion. Defrosting the accumulated ice from the vapour condenser is bywater, and hot water is recommended to speed up the defrosting cycle.

5. Vacuum system

The vacuum system is composed of drying chamber, condenser, vacuum pipes, valvesand vacuum pumps. It requires no leaks; Vacuum system is an essential for the rapidsublimation. Roots pump is required for large scaled system to give efficient capacityfor evacuation. Brand: Leybold.

6. Heating system

The heat-plates are cooled and heated with a heat transfer fluid. This fluid can bechilled or heated to provide in-place freezing or heating of the product during thedrying cycle.An electric boiler directly heats the fluid, and chilling is through an

intermediate heat exchanger. A centrifugal pump provides the forced circulation of theheat transfer fluid.

7. Refrigeration system

The refrigeration system freezes the heat plates during in-place freezing, evacuationand the early stages of drying. It also cools the vapour condenser during the dryingcycle.The screw compressor is adopted on the large scaled equipment and piston forsmall ones, and the refrigerant used is R404A, R507.Brand: Bitzer

8. Defrost system

Water is used for defrosting the vapour condenser.As an optional extra, heat can bereclaimed from the refrigeration compressor to enable 60°C hot water defrost, greatlyreducing defrosting times over conventional cold water.

9. Control system

CE or UL approved Siemens or Advantech PLC is adopted for control system.Allelectrical components are compatible with local supplies including voltagc, frequency,wire, motor circuit breakers and overload protection.A variety of sensors support thedata acquisition and control of freeze dryer: Pressure transducers are fitted, whichmonitor and control the refrigeration system. Vacuum pressure is monitored at theproduct chamber. Temperature sensors measure and control the heating fluid.