Page 236 - WaterSense at Work

October 2012
While steam sterilizers with dry vacuum pumps are available in Europe, they are still
not available in the United States at this time.
Operation, Maintenance, and User Education
To optimize the water efficiency of a steam sterilizer, consider the following opera-
tion, maintenance, and user education techniques:
Adjust the tempering water needle valve flow rate to the minimum manufacturer
recommendations and periodically review and readjust to ensure no unneces-
sary water is discharged to the drain.
Change out the needle valve annually, because they can wear quickly. Worn
valves can discharge excess water.
If the steam sterilizer is already equipped with a thermostatically actuated valve
to control tempering water flow, periodically check the valve to ensure it is open-
ing and closing properly, so tempering water is not continuously discharged.
Shut off the steam sterilizer unit when not in use.
Use high-quality water to generate steam to improve the efficiency of the steam
Retrofit Options
There are two retrofit approaches to reduce the water use associated with steam ster-
ilizers. One approach addresses the use of tempering water, and the other addresses
the water used to create the vacuum in the sterilization chamber. Depending upon
the operational settings, frequency, and timing of sterilizer use and whether the tem-
pering water flows continuously, retrofitting a conventional steam sterilizer to reduce
its water use can be cost-effective.
TemperingWater Retrofit
To reduce the amount of tempering water necessary to cool the steam condensate
that is discharged, replace the standard needle valve with a thermostatically actu-
ated valve. This type of valve can monitor the temperature of the condensate and
will adjust and minimize the flow of cooling water necessary to maintain a discharge
temperature below 140°F. In addition, consider diverting the steam condensate into a
small, uninsulated tank prior to discharge. This tank will allow the condensate to cool
through heat exchange with the ambient air to the point where little to no additional
cooling water is required to meet the 140° F temperature discharge requirement.
Vacuum Retrofit
Vacuum units contain an ejector that creates the vacuum in the sterilization chamber.
Water is typically passed through the ejector at a very high flow rate before it is dis-
Steam Sterilizers
Pages 23-34.