Bio-Rad Helios® Gene Gun System - Manual (Page 30)

Fig. 15. LED display of the Helios Gene Gun. Using a pressurized system, once the cartridge holder of
the Gene Gun is correctly inserted and engaged in postion 1, the five CHARGING lights will be sequen-
tially illuminated. Once the unit is fully charged (~5 sec), the CHARGED light will flash. If the safety interlock
is then pressed, the ARMED lights will alternately flash. If the safety interlock continues to be pressed (in
this ARMED state) and the trigger button is pressed, the helium will discharge and the FIRED light will
then be illuminated for one second. The process of charging and arming the gun occurs automatically
after it is fired. The green battery light in the BATTERY STATUS window indicates that the battery is good.
3. Start the flow of helium as follows: (Note: If a continous gas leak is observed after open-
ing either the cylinder valve or the regulator adjustment screw, close the appropriate valve
and check the tightness of the fitting. Contact Bio-Rad if a system leak persists.)
a. Close the helium pressure regulator by turning the regulator adjustment screw counter-
clockwise until the adjusting spring pressure is released and the screw moves without resistance.
b. Release helium into the pressure regulator by slowly opening the cylinder valve on the
helium tank; open the valve fully. The helium pressure in the tank is indicated on the
high pressure gauge (the one closest to the cylinder). Verify that the pressure in the
tank is at least as high as the desired discharge pressure.
c. Open the helium pressure regulator using the regulator adjustment screw and set the
discharge pressure to the desired setting (100–600 psi). The pressure to the system is
indicated by the low pressure gauge on the regulator. Do not set the discharge pres-
sure above 600 psi; the helium regulator has an over-pressure relief valve that will vent
the system at 700 ± 50 psi. Additionally, the regulator is self-venting: turning the the
regulator adjustment screw counterclockwise will reduce pressure to the system.
4. Put on hearing and eye protection, point the device away from any by-standers, and
depress the trigger 2–3 times to discharge the device as described below. If this step is
performed without a cylinder in place, the O-rings may be blown out.
a. For right handed users (see Figure 16):
Engage the safety interlock switch by pushing in with the thumb.
Push the firing trigger with the index finger to discharge the cartridge.
b. For left handed users:
Engage the safety interlock switch by pushing it in with the lower part of the index finger.
Push the firing trigger with the index finger to discharge the cartridge.
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