Gow-Mac 400 Series, Руководство по эксплуатации

Страница: 51 / 64

51 Series 400 / 402 Gas Chromatograph Operating Manual GOW-MAC Instrument Co.
May 2017, Rev. 7
9.8 Column Oven Temperature Control
The column oven is heated by a 500 W tubular heater controlled by a proportional control.
The solid state control incorporates a platinum RTD (Resistance Temperature Detector and
a 3-1/4 turn set potentiometer. Built into the circuitry is a fail-safe feature which disables the
controller's triac output in the event of shorted or open sensor.
The "Temperature Fail Safe" feature has independent shut down at 400 °C for injection ports
and detector. The column oven shuts down 30 °C above the column oven set point. The
heating units return to safe condition when the temperatures decrease to safe levels. The
controller is easily removed for service or replacement.
9.9 Detector Temperature Control
The detector is heated by a 100 W heater mounted in the DETECTOR HOUSING. The
temperature control sensor is also located in the housing.
The detector temperature is controlled in the same manner as the column oven.
It is IMPORTANT to remember that the detector is heated by fi laments as well as the heaters,
and
CANNOT be operated at ambient temperature. Even with the heaters turned "OFF",
the detector will rise in temperature to about 70 °C due to the heat being dissipated by the
fi laments.
9.10 Injector Temperature Control
The injection ports are heated by 60 W heaters mounted inside the injector block. The
temperature control sensor is also located in the block.
The injection port temperature is controlled in the same manner as the column oven.
9.11 Power Supply
A. The power supply consists of a power transformer, rectifi er circuit, integrated circuit and
external power pass transistor.
1.
Power Transformer
: A step-down transformer is used to reduce the AC voltage
to 24 V. The transformer is designed for both 50 and 60 Hz operation. Two trans
formers are available for proper matching with the AC line voltage, i.e., 115 and 230 V.
2.
Rectifi er Circuit
: A full wave type silicon bridge rectifi er is used to convert the AC
voltage from the secondary of the power transformer to pulsating direct current. A
capacitor input fi lter is used to smooth out the pulsating direct current.
3.
Integrated Circuit
: A solid state, silicon, monolithic integrated circuit regulator is used
to regulate the DC output of the power supply. This provides line voltage regulation of
less than ± 0.25%. An external voltage control provides continue adjustment of the
output voltage from 3 to 20 DC. This control is marked
CURRENT on the front panel of
the GC.