Section 2
Principle of Operation and Features
a. Detection Principle:
The DigiCal Calibrator utilizes the principle of measuring the flow
rate of gases over a fixed volume per unit of time. A Quartz
controlled timer is the timing device and the fixed volume is located
in the flow cell center tube. A microprocessor measures the time
for a frictionless soap film to travel from the first sensor to the
second sensor (infrared which detects the passage up the tube) and
then calculates the volume per unit of time. The results are
displayed in flow rate, cc/min. on a four digit liquid crystal display.
The decimal point floats to present the data in the proper range. The
timer is capable of detecting a soap film at 80 microsecond
intervals. This speed allows under steady flow conditions an
accuracy of +/- 0.5% of any display. The unique flow cell can
create a soap film over a range of 1 cc/min. to 6,000 cc/min. The
flow cell is spillproof when properly filled.
b. Understanding the Display Results
A unique feature of the microcomputer software program is data
display. On initiation, the DigiCal display will present 8888’s for 3
seconds and then display 0000’s with no decimal point indicated. A
series of ---- are displayed while a test is in progress. During
sequential tests, the previous reading is added to the current test, the
previous reading is added to the current test as a running total. The
letter A-appears after each test display the number in the averaging.
If the previous reading and current reading are different by more
than +
5% a series of EEEE's will flash four times on the display
and then display the actual last test result. The next flow readings
will start this averaging technique over again. If individual readings
are desired without averaging, the "ON" button may be pushed to
reset the unit to "0000" following each test. The flashing numbers
on the display after a test are for three seconds duration. The
purpose is to allow sufficient time for the soap to return to the
bottom reservoir.
4
Section 5
Calibrator Maintenance
General Information:
To clean the flow cell, simply remove the three screws holding the flow
cell to the bottom of the case. Remove the flow cell and gently flush
with tap water. To prevent scratching the acrylic flow cell, wipe "only"
with a soft cloth. Do not allow center tube, where sensors detect soap
film to be scratched or get dirty. NEVER clean with ACETONE. Use
only soap and warm water. When cleaning prior to storage, allow flow
cell to air dry. Shake any access water from cell prior to reattaching to
base of DigiCal Calibrator.
If stubborn residue persists, remove the bottom plate. Squirt a few drops
of soap into slot between base and flow cell to ease removal. Gently
insert a coin or flat screw driver into the ridge between the bottom plate
and chamber using leverage around the circumference of the cell until
the bottom plate is removed. Upon realigning, note scribe mark near one
of the screw inserts on bottom plate and align this mark with scribe mark
on flow cell near air hose inlet. Again, wet O-ring with soap prior to
installation.
To reassemble, realign flow cell in case with hose nipples pointing to
back of case and reinstall the three bottom screws.
Section 6
Calibrator Verification
The calibrator is factory calibrated using a standard traceable to National
Institute of Science and Technology (N.I.S.T.). Attempts to verify
calibrator against a glass one liter buret should be conducted at 1000cc/
min. for maximum accuracy. The calibrator is linear throughout the
entire range due to the detection technique of “fixed volume per unit of
time.” See Section 1 for principle of operation.
9
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comments to this Manuals