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newsletter spring 2003 |
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Interceding for St. Jude
Facing a one-time SAC fee of $85,000 for increased
water use may seem like a desperate situation—but not
for St. Jude.
St. Jude Medical’s Maplewood facility
manufactures heart valve components. An important step in
its manufacturing process is pyrolytic carbon coating of the
components. In this process, cooling capabilities are critical
to ensure product quality. Through 2001, coating reactor cooling
was accomplished with an average use of 20,000 gpd of city
water. Most of this water was then used to clean screens in
the associated scrubber. Changes in city water temperature
and pressure required operators at St. Jude to monitor reactor
temperatures closely and adjust water flows frequently.
Karl
DeWahl, MnTAP engineer, visited the St. Jude facility
to help maximize efficiency. “Karl was very detailed.
He recommended changes to help us reduce water use and save
money,” said Mike Jackson, coating engineer at the Maplewood
facility.
Gaining control
The big change Jackson wanted was implementing a recirculating
cooling-loop system he designed to gain better control of
the coating process. This system consisted of three 5,000-gallon
storage tanks with pumps, piping and temperature controls
to circulate the water through the reactors and back to the
tanks. The volume of water in the tanks is sufficient to cool
one day’s production with no outside cooling needed.
It also provides a backup supply so that repairs could be
made without shutting down the coating process.
Installed, the new cooling system cost $120,000
and reuses about 10,000 gpd of water from the coating reactor
cooling for makeup to the scrubber.
Avoiding a SAC
When Jackson recommended his recirculating cooling-loop system,
St. Jude was faced with a one-time SAC fee of $85,000 for
increased water use. Avoiding the SAC fee was a big incentive
for the facility to implement Jackson’s design. The facility
also saves $20,000 annually on water use. The new system design
had a projected payback of two years.
According to Jackson, “Five million
gallons of water per year in the coating process has been
reduced. [This is an] 80 percent reduction in the department’s
water demand and about a 50 percent reduction for the entire
facility.”
“Implementing this system reduced long
term operating costs and gave us a stable and reliable cooling
water system and also resulted in improved production yields,”
concluded Jackson.
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