Inficon HAPSITE Smart, Руководство по эксплуатации

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B - 2
IP
N 07
4-
39
7-
P1
G
HAPSITE Smart Operating Manual
The concentrations for calibration of the various target compounds will probably be
defined in the method being followed. The method may specify, for example, 0.1
ppm, 1 ppm, and 10 ppm of each compound. Calibrate the HAPSITE to bracket the
concentrations at which the target compounds will occur in samples.
The mixtures received will be tagged with the precise value of the concentration of
each compound as delivered; these will be approximately the concentrations
ordered. The concentration supplied will generally be within ±10% tolerance; this
is termed the
blend accuracy.
The precise values are the ones to be used in the course of building the calibration
libraries, and are accurate to +2 -20 %, depending on the target concentration
levels and the certification methods used; this is termed the
analytical accuracy.
The certified concentrations in each cylinder mixture will generally be stable at
room temperature conditions for about six months.
The selected gas supplier should be able to advise about the reactivity of the
compounds needed, and the materials of cylinder construction to provide the best
long term stability of the concentration. The supplier will recommend the use of
stainless steel regulators with stainless diaphragms. To minimize stagnant volumes
where VOCs can accumulate the regulator body should be designed with minimum
internal dead-volume. Use 1 " diameter gauges, or eliminate the gauges altogether.
The regulators and the tubing following should be rated for high purity, mildly
corrosive (or corrosive) service if any halogenated VOC's are to be delivered.
NOTE: A regulator/transfer line system must be well purged with pure nitrogen or
air to remove any residual VOCs prior to use with a cylinder containing a
lower concentration mix.
Transfer fittings should be of the stainless steel Swagelok
2
type, and transfer lines
should be clean, stainless steel or nickel 1/8 inch tubing. Teflon tubing should be
avoided due to its permeability. Ideally, regulators and transfer lines should be
heat-traced to maintain above ambient temperatures (35-55 °C) and to reduce
adsorption of the higher boiling VOC's.
B.1.1.2 Diluting the Gas On SIte
The comments above, concerning hardware, relate as well to the case of dilution
systems. Guidelines to verify acceptable performance of suitable dynamic gas
mixing/dilution systems are suggested in the Federal Register (vol. 59, No. 148,
Aug. 3, 1994 Proposed Rules, 40 CFR Part 51 Method 205),
Systems conforming to the Method 205 suggestions are available commercially
from Environics
3
(Series 2014 Computerized VOC Gas Dilution System) and
Alltech
4
(GB-2 Gas Blender).
2.Swagelock (Crawford Fitting Company): (216) 248-4600
3.Environics: (203) 429-5040
4.Alltech: (800) 255-8324