Planmeca Compact I Technical Manual page 165

SUCTION SYSTEM RELATED
Pulse valve opens (after every five seconds)
Technical Manual
Pulse valve
Electrical function:
Control voltage is connected to the microvac, pulse and
flushing valves.
Pneumatical function:
The vacuum is connected to the membrane assembly
(drain and intermediate membranes). The intermediate
membrane is forced to shrink by the vacuum. The pres-
Breather
sure balancing membrane stays in position (due to the
valve
pressure difference between the chambers) preventing
water from flowing to the lower chamber. The drain mem-
brane blocks the opening from the lower chamber to the
drain. The vacuum also closes the breather valve.
Intermediate
membrane
Membrane
assembly
Drain membrane
After about 0.5 seconds the pressure difference between
the chambers is balanced by the pressure balancing tube.
The pressure balancing membrane moves downwards
due to gravity allowing saliva and water to flow to the lower
chamber.
Pressure
balancing tube
Chapter G - PARTS REPLACEMENT & REPAIR
Planmeca Compact i G-15