manufacturer :       Leybold

model :                   GT 2

annotation :           Dokumente engl.

Description of the basic plant GT 2

The GT 2 freeze drier is placed on a fable er a trolley. The vacuum pump is set on the fioor or on the lower sheft of the trolley (1) and is connected to the plant by PVC tubing (13).

The vacuum manifold or base plate (6) with the drying bell jar (8) is placed on the vacu­um intake port. The various accessories — see Technical Data and Seeäon 4 — allow multiple use of the freeze drier.

The plant is evacuated with the two-stage vacuum pump (2). When the pump is switched off, the built-in intake port valve closes automatically, the vacuum in the plant is maintained, the vacuum pump it­self is vented.

The ice condenser is cooled to the final temperature as indicated in the Technical Data by a one-stage refrigerator. its con­densation area is designed as to take up large quantities of water at the beginning of the process and net to exceed ice layers higher than 1 to 2 cm at maximum load. Defrosting is by a radiation heater in the center.

The refrigerator for the ice condenser is air-cooled. lt operates with Freon R 22 and is equipped with a fully enclosed compres­sor (20). The liquid coolant is supplied from the air-cooled condenser (22) via a drying cartridge (23) to the expansion valve (24). The coolant evaporating behind the ex­pansion valve (24) in the ice condenser (evaporator) (25) is sucked on by the com­pressor and returned to the condenser. The fan (21) supplies cold air to the condenser.

A shut-off valve is fitted between ice con­denser and drying chamber er vacuum manifold respectively. lt allows pressure control and pressure rise measurements to be carried out in the drying chamber.

The electrica equipment of the freeze drier comprises of: power supply and control module with vacuum gauge and programme switch. The basic equipment Cat. No. 042 50 B 1 comprises in addition of the controller for electrically heated product shelves and of a temperature controller (9c).

The individual operational steps are solected by means of the programme switch (9a).

Programme switch positions:

"OFF": all assembly units switched off.

"CONDENSER PRE-COOLING": The refrig­erator is switched an to pre-cool the con­denser.

"DRYING": Refrigerator operating, vacuum pump and vacuum gauge are switched on. In freeze driers with electrically heated pro­duct shelves also the heater is switched on.

"DEFROSTING": Refrigerator, vacuum pump, vacuum gauge and heating of pro­duct shelves if any — are switched off. The defroster is switched in.

Technical Data

Vacuum pump                           Typ               GT 2

Filling of special oil N 62

min./max.                                   I                    0,5/0,7

Ice condenser

Final temperature                       °C                 <-45

Capacity, approx.                       kg                 2

Defroster                                    kW                0,3

Refrigerator

System with one stage              Typ               Danfoss-Kapsel

Compressor                                                   PW 11 x 22 T 2

Refrigerant                                 Frigen           R22

Expansion valve on:

    Ice condenser                         Typ               TCE 1 HXxG1 ,8

  ( evaporator )

Main supply                                V, Hz            220~, 50(60)

Power requirement without

Heater, approx.                          kVA               1 ,2

Vacuum gauge                           Typ               THERMOVAC TM 201

Dimensions of plant

(Height x width x depth)             mm               570 x 560 x 300

Weight, approx.                          kg                 80 (with pump)