Bypass or Remove a Water Tower using CSV

[Tom101]

Can a CSV help if there is a hole in the Water Tower or it needs to taken out of line for cleaning and painting?

[Cary Austin]

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 it’s 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 being used from the tower. Maintaining a level in a tower can also eliminate line breaks usually associated with starting and stopping flow or pumps.

[Tom101]

If the CSV will supply any amount of water the city is needing, why do I need to spend $190,000.00 repairing the Water Tower?

[Cary Austin]

You Don't!!!
The old way of system control was to fill a water tower or pressure tank and shut off the pump. The system demand would then empty the tank and the pump would be restarted. This process is repeated over and over because system demand is usually much less flow than the pump produces. The tank is repeatedly filled at maximum pump flow and drained at the rate of demand. This cycling on and off of the pump system causes a multitude of problems. Everything from the generators at the power station to the plumbing in individual houses or irrigation systems is stressed from the cycling of the pump. End rush currents from pumps starting stresses electrical components in the power grid from the generator to the pump motor itself. Water hammer and surge from pumps starting and stopping stresses tanks, valves, and all piping in the distribution system. Long water lines between the pump and the pressure tank, water tower, or storage tank are especially vulnerable. Changing the flow in these long lines from a dead stop to full pump flow then back to a dead stop, can cause tremendous surges, or swings in pressure, that are responsible for numerous and expensive line breaks.

Cycle Stop Valves vary the pump output to exactly match the demand. A jockey and or a base load pump runs continuously and is throttled with a Cycle Stop Valve to exactly match the demand. When demand is greater than these small pumps can produce, larger pumps are brought on line as needed, and their output is throttled with a Cycle Stop Valve to continue matching the flow demanded. When flow demanded is reduced, larger pumps are turned off when no longer needed. The base load and or jockey pump will continue to run matching smaller flow rates as long as at least 5 GPM is being demanded. Continuous and instantaneous matching of the demand instead of completely starting and stopping the flow eliminates pressure surges in pipelines and reduces end rush required to frequently start pump motors. Continuous matching of the demand also reduces or eliminates the need for large pressure tanks and water towers, further benefitting the system.

[Tom101]

What do I do about fire protection during a power outage?

[Cary Austin]

Large hydro tanks are designed to limit the number of pump cycles, not for water storage. A 10,000 gallon hydro tank only has about 1,200 gallons of useable water, the rest is air space. During a power outage this 1,200 gallons of useable water only gives a few minutes of water as pressure rapidly decreases to nothing. A water tower will deliver more water during a power outage but, depending on the rate of usage at the time, could still be out of water in a couple of hours or even minutea. Real backup water supply means being able to utilize water from the main reservoir during a power outage. A backup generator or a diesel powered backup pump can continue to supply the system as long as there is water in the main reservoir. This can change the backup water supply from minutes or a couple of hours to several days, weeks, even months if need be. These backup pumps or generators can give an almost unlimited supply of water for a fraction of the price of a water tower.

Los Alamos, New Mexico had a tremendous wildfire a few years ago.  The fire first interrupted the power supply to the water pumps.  The Water Tower, which might have given 100,000 gallons, was inadequate to fight the fire as it was quickly empty.  An eight million gallon storage tank full of water was unable to be utilized because no backup generator or diesel powered pump was available.  A backup generator cost a fraction of the price of a Water Tower and would have made eight million gallons quickly available to fight the fire.  A Water Tower is just an over priced false sense of security.

http://cyclestopvalves.com/techq_19.html