Teledyne 3300TB, Руководство по эксплуатации, Страница: 31 / 51

Installation Model 3300TB
Teledyne Analytical Instruments 18
CAUTION: There could be hazardous voltage at the alarms
terminals, even when power is removed from the
instrument.
3.4 Gas Connections
The standard Model 3300TB has two inlets and one outlet fixture
only. Calibration gasses can be connected into the "Span" inlet. All of
the gas connections are 1/4 inch brass fittings.
A switching valve is provided to feed the analysis unit with either
sample or gas.
A flowmeter and flow controller valve are part of the system and
will assist in setting the flow of the gas.
Sample flow should be adjusted to 2 SCFH. The sample vent
connection should not restrict the sample flow. The sensor is designed
to operate at atmospheric pressure. Restricting the sample vent line will
result in pressurizing the sensor and altering the O2 reading.
The pressure required will depend on the sampling system. When
venting into a constant pressure, such as the atmosphere, controlling
input pressure is simple. If you are venting into a system of varying
pressure, then some form of pressure regulation is required to maintain a
constant pressure across the sensor.
The Sample and Span pressure is not to exceed 50 psig (345 kPa).
3.4.1 Vacuum Service Option
For vacuum service pluming reference Figure 3-4. The vacuum
service option is recommended for applications in which the sample
source is not pressurized. The customer must supply a pump and by-
pass system to complete the sample system. The sample inlet and outlet
pressure must be maintained at a constant pressure for proper
performance. If the sample inlet or vent pressure will not be held
constant during the process, a pressure regulator must be used to
regulate the pressure across the cell.
Adjust the flow rate on a vacuum service system as follows: