LumaSense Technologies M340 - Manual (Page 11)

M340 Manual Installation 11
3 Installation
3.1 Normal use
(20 °C to 150 °C and occasional short term from 0 °C to 20 °C)
Normal use means that for most occasions, the M340 will be set to temperatures above ambient
or about 20 °C to 150 °C. No purge gas installation is required. Notice on the rear panel, there is
a connection for DRY N2 PURGE. This is an inlet for a supply of dry nitrogen purge gas that is
required only when planning to set the M340 at temperatures below the environment dew
point (usually less than 10 °C in normal calibration labs depending on relative humidity) for
extended times. Nitrogen purge gas is NOT required for normal use as mentioned above. Skip to
Location section below.
3.2 Low Temperature Use
(-20 °C to 0 °C even for short term (purge gas required)
Every blackbody source requires knowledge of and maintaining of the emitter surface in order
to keep the emissivity at a known, controlled value. When operating at temperatures below the
room’s dew point, moisture will condense (and freeze if set below 0 °C) on the emitter surface
which will cause the emitter emissivity to change drastically. Once the emissivity changes, the
integrity of the measurement disappears making calibration results erroneous. To prevent
moisture or ice from forming on the emitter at these temperatures, clean, dry instrument air
(dew point <-21 °C) or nitrogen (preferred) must flow as a protective “blanket” across the
emitter surface.
Notice on the rear panel, there is a connection for DRY N2 PURGE. This is the inlet for a supply
of dry nitrogen purge gas that is required only when planning to set the M340 at temperatures
below the environment dew point which is usually less than 10 °C in normal calibration labs
depending on relative humidity. Nitrogen purge gas is required when operating at setpoints
below 0 °C even for short periods and is recommended if planning to operate lower than 0 °C.
3.3 Purge Gas Requirements
Supply pressure: No more than 10 PSI into a needle valve rotameter (flow indicator with
adjustment valve)
Flow rate: 6 to 8 CFH (cubic feet per hour) adjusted using a needle valve rotameter
Connection: 1/8 NPT female on rear panel
Read type of usage section above. You may not require purge gas installation.
3.4 Location
Select a stable location on which to place the M340. Since any blackbody source stability can be
affected by moving air currents near the emitter, avoid locations where air currents are active
such as near vents, walkways for people, etc.
3.5 Air Inlet/Outlet Clearance
The thermoelectric system requires constant air flow across the internal heat sink for proper
operation. The air inlet (fan) on the rear panel must not be obstructed as well as the air outlet
screen on the right side of the M340. Allow at least 3 inches clearance for both inlet and outlet
regions. Blocking either of these ports will degrade performance and cause failures. If clearance