Geosense VWNPC-3000, Инструкция по эксплуатации

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14
V1.4 March 15
5.1.4 Initial readings
5.2 Re
-
Pressurising the Cell
During concrete curing, temperatures very often rise and will cause the cell to expand in
the still green concrete. On cooling, the cell contracts leaving a space between it and the
surrounding concrete which, if allowed to remain, would prevent the transmission of
pressures from the concrete to the cell. Therefore the cell will require to be
re
-
pressurised in order to measure this pressure.
STEP 1
-
connect the sensor cable to the readout (for full
details see page 9)
STEP 2
-
start crimping the re
-
pressurisation tube from
the end cap end with the special crimping tool.
Check the readings on the readout as the tube is
crimped. If there is a relatively large gap between the cell
and the surrounding concrete each crimp will result in a
small value increase in pressure. If the cell is already in
good contact with the concrete then a large value will be
seen.
ONCE TEMPERATURE HAS STABILISED
TAKE INITIAL PRESSURE & TEMPERATURE
BEFORE RE
-
PRESSURISING
DO NOT START CRIMPING THE TUBE
CLOSER THAN 25MM FROM THE END CAP
STEP 3
-
plot a graph of pressure against the number of
crimps.
If the gap between the cell and the concrete is relatively
large then the curve will be as graph 1 on page 15.
If the gap between the cell and the concrete is small the
curve on the graph will be as graph 2 on page 15.
BEFORE SHOTCRETING TAKE INITIAL
PRESSURE & TEMPERATURE READINGS