PlasmaQuant MS Series
Gas
Control System
35
Figure 5-1 - Inside Gas Control Box
Enables/disables the flow of argon gas entering the instrument
Senses that the argon gas supply is above the minimum pressure (460 kPa)
Controls the flow of argon gas to the torch and nebulizer (plasma, auxiliary, sheath
and nebulizer gases)
Controls the igniter (used for plasma ignition)
Controls the gate and small isolation valve, used to reduce the “surge” on the
vacuum system when the main (large) isolation valve opens (used to isolate the
instrument vacuum system from atmospheric pressure)
The instrument gas supply enters the gas box by a Teflon® hose terminated at the
gas box input port by a Swagelok fitting. The operational inlet-pressure range is
600 to 830 kPa (87 to 120 psi).
A pressure-sensor switch, mounted on the inlet manifold, monitors gas pressure from
the argon inlet-supply hose. This switch is factory set and connected to the ASSY PCB
SAMPLE INTRODUCTION (10-5-0220006800). If the argon inlet pressure drops below
460 ± 5 kPa (66 ± 0.75 psi), the sensor opens. The open switch triggers the sample
introduction PCB to generate the PC software error
low argon pressure
. The
instrument does not monitor the upper limit of the pressure range.
The instrument gas supply then passes through a gas 24 VDC solenoid,
interfaced to the sample introduction PCB and mounted on the inlet gas line after the
gas pressure switch.
The main inlet solenoid supplies two regulators. The first regulator (RG1) is set to 175
± 5 kPa (25 ± 0.75 psi) and supplies gas to the gas-supply manifold.
The gas-supply manifold is a solenoid driven device that controls the plasma and
auxiliary argon flow to the torch. S24 VDC solenoids, when turned on, allow
argon to pass through precision orifice jewels. The selected output flows are grouped
together by function.
The gas box assembly: