K5 Drinking Water Station
Section 7 Drinking Water Systems Revised: 09/2016
Page 10
the outside of the WOW tank bladder pressurizing the outer chamber and forces permeate
water through the postfilter and out to the faucet. The force of water delivered to the tap is
directly proportional to the supply pressure, unlike air charge storage systems. A small amount
of drive water is vented to drain through the reject flow control during delivery.
At delivery, the permeate pressure at the feed port quickly falls below 1/3 line pressure after the
faucet is opened. The feed pressure, operating at reduced effective area against the lower
diaphragm, now defeats the permeate pressure on the upper diaphragm and opens the feed
path to the membrane. Permeate production starts. Now exerting against a larger lower
diaphragm area again, the feed pressure holds the RO control open until permeate pressure
again reaches slightly higher than 2/3 supply pressure.
End of Delivery
The tap is shut. Pressure rises in the delivery line and forces the drive valve down and holds it
there due to the piston’s larger hydraulic area. Drive water supply is now shut off by the drive
valve, and the residual pressure on the permeate side of the WOW tank is slowly released by a
flow control. Tank pressure decays slowly until it reaches 12 psi at which point the spring under
the vent valve is able to overcome the downward force of the vent valve. The vent valve then
opens upwardly, allowing free depressurization of the drive side of the storage tank.
To Next Page
Loading...
Need help?
General
