June 20, 2000 Looking from the North, more than 2 1/2 years later. The bolted tank on the right is wet with sweat. The welded tank on the left is dry.

JUNE 20, 2000 The welded tank is dry. No sweat, no dirt sticking to or mold growing on it.

JUNE 20, 2000 The bolted tank is wet with sweat and covered with mold.

JUNE 20, 2000 Looking from the South. The bolted tank has heavy mold growth up 12 to 15 feet. The sweat line is visible on this picture.

JUNE 20, 2000 The welded tank is dry and as neat and clean now as it was 2 1/2 years ago.

This was the first full size test installation.

The tank has a single 12 inch fill/discharge pipe that runs about 100 feet to the county road. There it reduces to an 8 inch distribution main. This triple check system has two (2) 6 inch intakes taking water from the tank, but they will not allow water into the tank.

It has one (1) 6 inch upper valve that lets water into the tank, but will not allow it to go out.

The extended fill pipe goes up about 47 feet, guaranteeing an automatic minimum system pressure of 20 PSI when refilling the tank. This system can put the water in at or near the top and take it out from the bottom just as surely and more economically than actually double piping a single pipe tank.

THIS POSITIVE RETENTION CIRCULATION SYSTEM IS AT IT’S BEST IN STANDPIPES AND GROUND STORAGE TANKS BUT IT IS ADAPTABLE TO AND BENEFICIAL IN MOST WATER STORAGE FACILITIES.

This system was installed in a 500,000 gallon C.B.I. Design Single Pedestal tank. The tank had an 18 foot extended fill that did not allow the city access to the lower half of the tank. It was held for fire protection at a factory. Changes in storage and distribution made that practice obsolete. Installing these valves provides full access to the contents and puts water in about halfway up in the container.

This installation was in a 200,000 gallon elevated tank with a 4 foot wet riser. Low water level is about 110 feet. High water level is about 150 feet. The fill/discharge line is 8 inch diameter.

Looking in through the open manhole at the riser bottom, a 3 inch intake valve provides access to and guarantees movement of water stored in the riser.

This photo shows the double 6 inch intake valves on the 8 inch fill/discharge pipe at about the 112 foot level.

Openings in the pipe, at the 136 and 140 foot levels, bring water into the tank. This is a treated surface water system and this tank does not sweat.

This is a 16 foot X 113 foot standpipe. The positive retention circulation system is installed using all 6 inch valves. Both valves are set to the right because there is a 24 inch diameter access manhole immediately on the left.

The fill pipe extends up 80 feet. The roof hatch is open. The new insect/frost proof vent is not yet on and the rigging ports are not capped.