Oerlikon Leybold Vacuum 129 78, Инструкция по установке и эксплуатации

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Description
7 GA12119_00_A3 - 01/2012 - © Oerlikon Leybold Vacuum
1 Description
Gifford-McMahon cryogenerators consist of:
■
the cold head,
■ the compressor unit,
■ and flexlines.
1.1 Design and Function
The cold heads COOLPOWER 5/100 (T), COOLPOWER 7/25, COOLPOWER
140 T and COOLPOWER 50 generate in connection with a compressor unit
“cryogenic” temperatures, i.e. temperatures below 120 K (K = Kelvin).
The COOLPOWER 5/100 (T) and 7/25 units are of a two-stage design, the
COOLPOWER 140 T and 50 are of a single-stage design.
A cold head is utilized e.g. to refrigerate samples or to cool shielding plates
or cryoanels.
A pair of flexlines connect it to a compressor unit. Cold head, flexlines and
compressor unit are equipped with self-sealing fittings and are filled with
high-purity, high-pressure helium gas.
Oerlikon Leybold Vacuum cryogenerators operate in a closed helium gas
cycle according to the Gifford-McMahon principle. In this process, helium gas
is compressed in a compressor. The pressure is then decreased in the cold
head to generate low temperatures.
A rotating control valve (1/8) controls the movement of the displacer, the
expansion of the helium gas in the cold head, and the pneumatic drive of the
displacement piston. The control valve is mounted on the shaft of a
synchronous motor (1/9) which is supplied with electric power from the
compressor unit.
The frequency of the compressor piston movement is 2 Hz at a line
frequency of 50 Hz, 2.4 Hz at a line frequency of 60 Hz.
For the two-stage cold heads, the displacer pistons of the 1st (1/3) and 2nd
stage (1/6) are mechanically interconnected.
A safety valve (1/11) protects the cold head against excessively high helium
pressure.
The cold head has a weld-on pipe (1/7) or a flange for mounting on the
system.
The refrigerating capacity of the refrigeration stages depends on the
temperature. Fig. 4 shows the characteristic curves for refrigerating capacity.
1.2 Standard Specification
Gifford-McMahon cold head with copper flanges, safety valve and power
cord with plug for connection to the compressor unit.
The cold head is filled with 16 bars of ultra-pure helium (99.999 % purity or
higher).
The COOLPOWER 5/100 (T) and 140 T have a mounted electrical cable with
plug for connection to the compressor unit.
Gifford-McMahon principle
Control valve
Safety valve