When the time comes for repair on your elevated tank or hydro tank, Cycle Stop Valves can keep a “constant pressure” on the city while the tank or tower is out of service.
Attaching a Cycle Stop Valve to the discharge of a pump or enough pumps to keep up with the peak demands will insure that the system will also work at 3 AM when there is very little demand. A Cycle Stop Valve will vary the output of a pump to match the required demand by maintaining a “constant pressure” on the distribution system. If demand increases, requiring a second pump, 10 PSI drop in system pressure triggers the second pump to start. With the first pump already at its maximum flow, the Cycle Stop Valve on the second pump restricts this pump to produce only the extra flow needed. When demand decreases and the first pump is again able to handle the demand, the Cycle Stop Valve on the first pump will bring the system pressure up 10 PSI triggering the second pump to shut off.
The first pump on line should be a small pump. This pump should be able to handle times of low demand and system leaks efficiently. The second pump should be larger, and combined with the first pump should be able to handle peak demands. Even more pumps can be brought on line if needed, and a back up generator can even insure fire protection during power outages.
The pump or pumps will continuously supply demand at exactly the same rate as the usage. It is important to have enough water in ground storage to supply the demand as needed.
When placing a tower back on line the Cycle Stop Valve can also maintain a “constant level” in the tower. A Cycle Stop Valve setting of 50 PSI will maintain a level in a tower if 115' regardless of the flow rate used from the tower. Maintaining a level in a tower can also eliminate line breaks usually associated with starting and stopping flow or pumps.
(See also "Replace Big Hydro Tanks with CSV and Small Tank" or "Alternatives to Water Towers and Hydro Tanks")
Link to Drawing
http://www.cyclestopvalves.com/forum/viewtopic.php?t=141
