Max300-LG : Description - Specifications - Installation Guide
Extrel
Core Mass Spectrometers
Page 14
specification. A digital “0” is –3 to 5 Volts and a digital “1” is 15 to 30 Volts. The inputs
are supplied in individually configurable eight bit blocks. Physical access to this
communication channel is via an external chassis that connects to the controlling PC.
Calibration Gases
Calibration gases must be suitable for the process stream. It is recommended that an
Extrel CMS application chemist is consulted prior to start-up for help in selecting gas
standards. Gas cylinders for housing calibration gases are typically 40-50 L or 1-2 ft
3
, 9in
diameter, 56in long, and filled to 2000 PSIG. If the vapor pressure of a compound limits
the pressure in the cylinder, a larger cylinder may be required to increase the time
between replacing them.
In general, three different classes of mixtures are used in calibration. The following are
Extrel CMS's recommendations for purity and grade:
1. Pure gases: Should be at least 99.999% pure, where the gas contains no more than 10
ppm total impurities. For multiplier applications, the gas should be 99.9999% pure.
2. Binary mixtures: These two gas mixtures should be at least 99.999% pure. The
accuracy of the reported concentrations is not critical unless the binary is also to be used
for sensitivity calibration. This case occurs primarily when a particular component is not
stable in the multiblend mixture. As a result, the sensitivity calibration for that
component may be done in the binary gas instead.
3. Multiblend mixtures: Are intended to simulate the process stream. Consequently,
they should be as free of impurities as possible and be certified to at least +/-2% relative.
Regulators
Two stage, high purity, medium flow regulators capable of handling 3000 PSIG inlet
pressure (cylinder pressure) should be used. Delivery pressure should be 1-30 PSIG with
a flow capacity of 300 scfh. The diaphragm, body and gauges should be stainless steel,
with seats and seals of Teflon
®
or a similar material. The outlet of the regulator should
have a shut off valve so flow can be stopped without depressurizing the regulator.
Fittings to connect the regulator to the gas cylinder are defined by the gas contained in
the cylinder. The gas supplier can advise as to the appropriate "CGA" fitting for various
gases.
Calibration Gas Connections
Installation of hardware to connect the calibration gas tanks to the MAX300
™
-LG is the
customers responsibility. The details of the connection may vary somewhat depending on
To Next Page
Loading...