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Change 1 28 April 2002
OPERATOR AND UNIT MAINTENANCE MANUAL
(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)
TANK, FABRIC, COLLAPSIBLE, WATER STORAGE,
20,000 AND 50,000 GALLONS
THEORY OF OPERATION
THEORY OF OPERATION
The 20K and 50K collapsible water tanks described in this manual are functional components of a water
distribution system. Any number of tanks may be connected to the system, depending on operational
requirements. Only two operator controls are utilized on the water tanks. They are: (1) the gate (or ball)
valve to control water flow during fill/discharge, and (2) the drain ball valve to control draining. For tank
models manufactured by GTA Container, a gate valve is used to control water flow. For tank models
manufactured by Reliance and MPC, a ball valve is used to control water flow. For specific operating
instructions, refer to Chapter 2.
Potable water to fill the water tank is supplied by a water distribution system. The system water pumps
draw water from the source (tanker truck, pipeline, or purification equipment) and pumps it into the water
tank through the filler assembly. Control of water flow between the supply pumps and the water tank is
accomplished by opening or closing gate valves within the system supply circuit. As the water tank fills,
the tank will enlarge. When the tank is full or no additional water is needed, supply circuit gate valves are
then closed. Excessive pressure caused by overfilling the tank is relieved by the vent fitting assembly.
The vent relief cap unseats when internal water pressure exceeds 0.10 psi (0.00680 atmospheres). The
4-inch gate or ball valve and 4-inch X 10 foot filler/discharge hose assembly supplied with the tank may
be installed on the filler elbow to control the water tank fill rate.
When needed, water is drawn from the tank by system suction pumps and distributed through a network
of valves and hoses to the field installed facilities. As water is drawn from the tank, the tank will flatten.
Water flow between the system discharge pumps and the water tank is controlled by the gate valves.
The 4-inch gate or ball valve and 4-inch X 10 foot filler/discharge hose assembly supplied with the tank
may be installed on the discharge elbow to control the water tank discharge rate. When the tank is empty
or no more water is needed, the downstream discharge gate or ball valves are then closed. Venting of
the tank during discharge is not required.
A 2-inch X 8 foot drain hose assembly is connected to each tank drain fitting. Ball valves attached to the
hoses are used to control water flow from the tank. These drain hose assemblies allow a restricted flow
of water from the tank for sampling or complete drainage. When preparing the tank for movement, the
system suction pumps will draw most of the water from the tank. To ensure complete drainage, the ball
valve is opened.
END OF WORK PACKAGE