Instruction manual

LS40/60 FREEZE DRYER

Publication reference 1HZ204-1 7

1.2 GENERAL SAFETY

WARNING: Warnings are given where failure to observe the instruction could result

in injury or death to persons.

CAUTION: Cautions are given where failure to observe the instruction could

damage to the equipment, associated equipment or process. Refer to the

accompanying manufacturers’ instruction manuals for the technical data on

individual components.

See Appendix 1 for list of Instruction Manuals.

WARNING: Sodium Azide Explosion Hazard

Sodium Azide, which is sometimes used in the freeze-drying process, is a toxic and

(when dry) highly explosive material. In the process of pumping product containing

this chemical, a reaction can occur in the presence of heavy metals (copper, lead,

zinc and cadmium). The resulting reaction is the formation of heavy metal azides

that are highly unstable, and which present a very severe explosion hazard.

Standard LS40 and LS60 freeze dryers are not suitable for use with Sodium

Azide. Please contact Severn Science if you wish to use Sodium Azide; the

equipment can be modified by the manufacturer for safe operation with Sodium

Azide if required.

1.3 GENERAL DESCRIPTION

1.3.1 FREEZE DRYING - BASIC PRINCIPLES

Freeze drying is a method used to dehydrate heat sensitive materials via a process involving the

sublimation of any water content (in the form of ice) under vacuum conditions. The process can

be subdivided into three (3) stages; freezing, primary drying, where the bulk of the water content

is removed by sublimation, and secondary drying where residual bound water is removed at

higher temperatures. The LS range of freeze dryers is capable of automatically performing all

these functions in a controlled and reproducible manner.

The equipment consists of a large vacuum drying chamber mounted directly above a

refrigerated condenser with integral vacuum pump. The drying chamber contains up to five

refrigerated shelves that can be moved up and down via an electrically operated ram for

stoppering processes. Both condenser and drying chambers are fitted with their own

refrigeration systems, specified for either high temperature (denoted model LS40) or low

temperature (model LS60) use. The temperature of the product shelves used in the LS40

can be controlled between +60

C and –40

C whereas shelf temperatures can be varied

between +60

C and –60

C for the LS60 version. Both systems have a compact footprint

allowing the equipment to be moved through standard sized doorways. Commissioning is

simple and straightforward, requiring no external services other than mains power. All

components are housed inside a free-standing cabinet with detachable inspection panels at

the front, rear and sides for easy maintenance.