Casella CEL Environmental enclosure for Microdust - Manual (Page 7)

3. THE VORTEX ASPIRATING PUMP
3.1 The Aspirating Pump
The Environmental Enclosure uses a modified version of the VORTEX
“Timer 2" personal sampler. This compact and reliable sampling pump is
designed to provide a flow rate capability of up to 4.0 litres/minute whilst
using a 37 mm GFA filter head (at up to 25 cm H
2
0 pressure drop).
Automatic flow control circuitry is used to maintain a stable sample flow rate
over varying pressure drop conditions.
The pump is powered directly from the 12 volt lead acid system battery.
3.2 Switching the Pump ON and OFF
To switch the pump on, press both keys on the VORTEX at the same time,
the buzzer will bleep twice and the green LED will be illuminated indicating
“PUMP ON”.
To switch the pump off, press both keys simultaneously until the pump
shuts down; all indicator lights should now be extinguished.
3.3 Resetting the “Elapsed Minutes” Counter
To return the count to zero, press and hold for 3 seconds. This can be
carried out while the pump is on or off.
3.4 Adjusting The Flow Rate
The pump is factory set to a flow rate of 3.5 litres/minute. Measurement of
the sample flow should be performed by connecting a suitable rotameter to
the inlet tube.
1. To adjust the flow rate, press and hold until the green LED
begins to flash.
2. Release the key.
The green LED will continue to flash for five seconds.
3. During this time you may press to increase the flow or to
reduce the flow.
The flow rate will change slowly at first then more quickly the longer
the key is held down.
operation. The pump incorporates a 0.9 µm filter and adjustable bleed valve.
The valve is factory set to provide approximately 0.5 litres/minute of purge air
when the main sample flow rate is 3.5 litres/ minute.
1.3 Power Supply
A sealed, rechargeable 12 volt, lead acid gel battery is used to power the
Environmental Enclosure and provides typically in excess of 24 hours
sampling. The pump is powered directly from this battery.
Whilst the Microdust pro contains its own batteries, a small power supply
control unit is used to provide additional power from the main 12 volt battery
and extends the instrument’s normal run time.
Observe the Battery Warnings on page 3.
Three versions of the enclosure are available; select the correct one for the
local mains supply.
176091A Enclosure for U.K. mains supply,
176092A Enclosure for European mains supply,
176093A Enclosure for U.S.A. mains supply.
Page 14 of 20 Page 7 of 20
Introduction VORTEX Pump
ENVIRONMENTAL ENCLOSURE
For MICRODUST pro - User Manual ENVIRONMENTAL ENCLOSURE
For MICRODUST pro - User Manual