Page 32 - Basic Gas Chromatography
P. 32

Overview  19  Measurement   and  Control   Flow      sensor  solid-state   a   uses  device  electronic  sophisticated   more  Another,   the   of   for  measurements   flow  accurate  permit   to  microprocessor   a   with  coupled   carrier   the   sensor  silicone-on-ceramic   A  bubbles.   soap  using  without   gases   of   range   a   in   run   oxygen,   air,   for  mL/min   500   to   0.1   of   rates   flow  measure   to   used   b


        Instrument   independent   conditions,   programmed   used   is   the   to   control   flowmeter   soap-film   buret)   or   soap   a   soap   through   gas  carrier   are  meters   light   with   easier   and   type.  electronic




              column,   these   a  during   sensor   pressure   pressure   soap-bubble   The   2.2).   pipet   bulb,  rubber   several   timed   the   flow   made   faster   is   rate.   from   Gas   chromatograph   digital


              the   Under   electronic   the   electronic   a   are   (Fig.   modified   a   After   gas.   accurately   measurement,   electronic   are   meter   flow   the   [   (6)   type

              through   valve.   electronically   An   flow.   increase   by   devices   device   a  (usually   squeezing   flowing   is  bubble   this   Some   measurements   flow   of       film  soap


              rate   purge   and   rate   used   measuring   By   the   one   From   electronic   readout   Q_)       (a)   (a)

              flow   the   of   increased   constant   rate   flow   tube   flows.   of   tube,   calculated.   the   but   an   three-digit   ~~  Soap   meters:

              same   closing   be   can   a   flow   constant   commonly   flow   calibrated   gas   path   the   stopwatch.   easily   $300,   Flow

              the   and   maintain   (decreasing)   a   Measurement   most   electronic   a   carrier   the   into   wet   to   a   with   is   principle,   around   a  provides   2.2.   Fig.
              maintains   opening   pressure   to   providing   two   digital   merely   the   allowed   volume   mL/min   same   cost


        18         gas   order   the   Flow   The   is   which   raised   in   the   a   and
   27   28   29   30   31   32   33   34   35   36   37