BT CGA-411 Operation Manual page 23

Water-stopper
The water-stopper (Fig. 6) is a floating check-valve, with push-button water release, to
stop water from being pumped while bar-holing. It provides a quick way to continue bar-holing
if water is encountered in a bar-hole.
The water stopper is inserted between the water-block and dust filter and the bar-hole
probe. The float inside the water-stopper is connected to a plunger which blocks flow whenever
the float is lifted by water. Water is released and the plunger is returned to its normal position by
depressing a release push-button.
Fig. 6. Water stopper for bar-holing.
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