1. Field of the Invention
The present invention is a method and apparatus for removing grit that collects in emergency water reservoir tanks.
2. Description of the Prior Art
Emergency fresh water reservoir tanks are sometimes provided in buildings and elsewhere in order to provide potable drinking water in the event of an emergency. In emergency situations that occur when natural disasters such as earthquakes, floods, hurricanes, and fires strike, the normal municipal supply of potable drinking water is cut off from the population stricken by such natural disasters at the time when potable drinking water is most needed. The same situation could well occur in the event of a terrorist attack or other emergency situation attributable to human actions.
In order to provide potable drinking water to a stranded population in such an emergency situation, emergency water reservoir tanks are sometimes installed in buildings and kept filled with potable drinking water so that a supply of drinking water is available to a localized population in the event of an emergency.
To keep the water fresh and potable, the emergency water reservoir is connected in-line between a municipal water supply line and a local water distribution line. In a residence the local water distribution line may be connected to a conventional hot water heating tank or to the building plumbing leading to toilets, shower heads and faucets. In commercial or industrial building such as factories, hospitals, and other large installations, the local water distribution line may be connected to boilers and cooling towers. One such emergency water reservoir system is described in my prior U.S. Pat. No. 4,962,789 issued Oct. 16, 1990, which is hereby incorporated by reference in its entirety.
By connecting an emergency water reservoir in-line with incoming water provided from a municipal water supply system and to an outlet to a local water distribution line servicing the building in which the emergency water tank is located, or possibly also other nearby buildings in a building complex, the water in the emergency water reservoir is continuously replenished. Fresh water is drawn continuously or intermittently through the emergency reservoir tank for normal water usage purposes.
One major problem exists, particularly in large emergency water reservoirs such as those employed in schools, hospitals, factories, and other commercial and industrial buildings and building complexes in which the water is directed to boilers and cooling tower filtration systems. Specifically, the grit and sand that is present in a municipal water supply is passed into boilers and cooling towers where it causes significant damage. Indeed, the entrainment of sand in municipal water supplies that damages boilers and cooling towers is quite prevalent in many municipalities.
The presence of grit and sand results whether or not a fresh water emergency reservoir is coupled in-line between the municipal water supply system and the local distribution line. The sand and grit in a municipal water supply system often enters the municipal water supply lines through pinholes that form in the water pipes. These pinholes are created through electrolysis. Even if the piping and pumping stations are both new, pinholes form very quickly in the piping. The suction from the pumps at the municipal water pumping stations causes sand to enter the pinholes and become entrained in the municipal water supply lines. Once this sand reaches commercial boilers or cooling tower filtration systems, it causes a blockage in valves, particularly needle valves, thereby resulting is damage to such system. As a consequence, commercial boilers and cooling towers must be repaired and maintained by frequently cleaning out accumulated sand and other grit.