Function and design
HS 55 (Batch Mode)
16
Figure 4 Batch module
1 "purge gas" gas supply
2 "transp. gas" gas supply
3 Metering hose for reduction agent
4 "to cell" gas outlet
5 Head
6 Reaction beaker
Reduction agent and purge gas are transported through the metering tip to the bottom
of the reaction beaker. The reaction with the sample initially takes place in the lower
part of the reaction beaker. The released reaction gas and the purge gas accelerate the
reaction. The purge gas drives the released metal hydride or Hg vapor out of the sample
solution. The transport gas ("transp. gas") enters the reaction beaker at the top. The
transport gas transports the metal hydride or the Hg vapor from the reaction beaker to
the atomizer in the AAS device or to the gold collector.
3.2.3
4-valve group for gas control
The 4-valve group provides fixed gas flows controlled by the software:
Valve MV2
Gas flow F2 with a flow of 15 l/h
¡
Constant purge gas flow through the pipette tip of the batch
module
Valves MV3/MV4
Gas flow F3 with a flow of 6 l/h and gas flow F4 with a flow of
25 l/h
¡
Transport gas flow: the flows can be selected individually or
as a total gas flow (31 l/h).
Valve MV5
The valve switches gas flows F3 and F4 either to the batch mod-
ule or to the gold collector to expel the released mercury.