Introduction
For many years Schutte & Koerting has provided portable eductors
to the U.S. Navy. These eductors were used for fire fighting onboard
ships. The units were used to increase the volume of water available
for fire fighting. They utilized the high pressure pumps onboard to
supply the motive flow to the eductor which was placed overboard.
The design of the unit was for high discharge head and typically had
a two-to-one flow ratio. (i.e. 100 gpm of motive, 200 gpm of suction,
with total flow of 300 gpm.)
Over
the past several years, Schutte & Koerting has worked with several
local fire fighters to develop an eductor designed to be used for
rural water supply operations. Many of us take for granted that
there is a fire hydrant on every corner. Unfortunately, this is
not the case. A large percentage of the fire companies outside large
cities depend on lakes, ponds, streams, rivers, and even swimming
pools as a water source during a fire. Water is currently accessed
from these sources in two ways. The first choice is to maneuver
the fire truck close (typically 30 feet or less) to the water source
and use the onboard pump to draft. This produces the greatest water
flow. In many cases, this is not possible due to weather or access
restrictions. The second option is to carry a large portable pump
to the water source and use this to draft the water and discharge
it back to a pumper truck or portable tank close to and accessible
to the fire trucks. Portable pumps large enough to supply sufficient
water flows tend to be large and require routine maintenance.
Schutte
& Koerting has developed an eductor to utilize the third option
for water supply. Our eductor utilizes the water stored onboard
the fire truck as the motive flow to start the eductor flow and
return the motive flow as well as the suction flow back to the fire
truck. This allows the fire truck to be at least 150 feet away from
the water and still achieve significant net water flow to be utilized
for fire fighting.
To
put the unit in operation, a 2-1/2 inch hose line and a 5 inch LDH
supply line are stretched from the fire truck with the eductor to
the water supply. The eductor is placed in the water and the motive
line is charged to 150 psig. This immediately starts the flow of
water back to the fire truck through the 5 inch LDH supply line.
Once the suction flow is established, the first portion of the flow
is used to replenish the tank water in the truck. Once the tank
has been replenished, the water supply has been established and
water can be supplied for use on the fire. The unit was designed
for 17.5 feet of head and during our prototype testing we were able
to achieve 750 gpm net suction gain. We supplied 200 gpm at 150
psig to the eductor, 750 gpm was developed as a suction flow with
a total flow back to the fire truck of 950 gpm. 200 gpm of the 950
gpm was being recycled back to supply the eductor.
Testing
was completed in the Spring of 2000 and marketing began in early
Autumn of that same year.
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