䡵
As shown in Fig. 7, attach the suspension cable of the bubble chamber to the
retainer on an OTT top cap already mounted. The retaining plate allows a fine
height adjustment afterwards.
䡵
Secure the suspension cable against slipping with a knot.
䡵
If top caps without retainers are used, ensure the suspension cable is attached
securely.
䡵
Check all knots and attachments for correct position and firmness.
䡵
Lower the bubble chamber slowly into the observation well with the suspension
cable.
䡵
Feed the measuring tube out of the observation well through a hole.
Top cap
Retai
n
er
Observatio
n
well
Suspe
n
sio
n
cable
bubble cha
m
ber
Securi
n
g k
n
ot
Retai
n
i
n
g plate
M
easuri
n
g tube
Fig. 7: Installing bubble chamber for
ground water – attaching suspension cable.
11