Bio-Rad PDS-1000 / He™ and Hepta™ Systems - Manual (Page 13)

2.2 Identification of Unit Controls and Components
The following is a brief description of the operation controls for the PDS-1000/He unit
(Figure 2.9)
Table 2.1. Unit Controls and Components
Controls and
Components
Description
Front View- Exterior
Power Switch, ON/OFF Controls supply of line electrical power to the
instrument.
Fire Switch Controls flow of helium into Gas Acceleration Tube by
activating Solenoid Valve. Illuminated red when
enabled, i.e. when safety interlock is satisfied that at
least 5 inches Hg. vacuum is present in chamber.
Fire Switch must be held ON continuously until
Rupture Disk bursts; then release Fire Switch to stop
flow of helium.
If the Fire Switch is released before the disk ruptures,
the helium is vented via a safety vent in the external
three-way metering (solenoid) valve.
Vac/Vent/Hold Switch Controls application of vacuum to bombardment
chamber. Vac applies vacuum from line source. Vent
releases vacuum using filtered air. Hold maintains
vacuum by isolating chamber.
Bombardments should be performed with this switch
in “Hold” position.
Vacuum Gauge Indicates level of vacuum in bombardment chamber,
in inches of mercury where zero equals ambient atmo-
spheric pressure.
Vacuum/Vent Rate Regulate rate of application and relief of vacuum in
Control Valves bombardment chamber. Clockwise rotation closes valves.
Helium Pressure Gauge Indicates helium pressure in Gas Acceleration Tube,
in psi. When solenoid valve is activated by Fire Switch,
the needle in this oil-filled gauge rotates clockwise until
rupture disk bursts. Watch this gauge carefully during a
bombardment and note the actual rupture pressure.
Gas Acceleration Tube Helium accumulates within this tube when it is sealed
by rupture disk at chamber-end of Tube. Helium PEEK
tubing connects at top of Gas Acceleration Tube outside,
rear of chamber.
Bombardment Chamber Holds Rupture Disk, Microcarrier Launch Assembly, and
biological target under vacuum during a bombardment.
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