9. Maintenance
●
Visually check that no abnormality is found in appearance of BHE.
If rust occurs or brazing material is eluted, leakage may occur. Replace early BHE with a new one.
●
During maintenance, flush the fluid at a rate of 1.2 times or more of operating flow rate to
discharge foreign materials from the inside of BHE. This can be made even more effective by
feeding in the compressed air at the same time.
●
Remove BHE from the piping, and flow the chemicals from the primary or secondary nozzles to
clean BHE. The following cleaning method is recommended.
●
Remove BHE from the piping, and strongly blow compressed air or fresh water from the fluid
outlet nozzles into BHE to flush out foreign materials from the inside.
Periodical Maintenance
Maintenance for decreasing of Flow Rate or Heat Transfer Performance, or increasing Pressure Drop
Example of chemicals
Acids
Alkalies
Aqueous Solution (Chemicals)
5% citric or oxalic acid aqueous solution
5% caustic soda aqueous solution
Cleaning Procedure
Process
Flushing
Flushing
Flushing
Acid cleaning
Alkaline
cleaning
Drying,
disinfection,
sterilization, etc.
Explanation
Flushing out for 20 to 40 minutes to completely replace the fluid with fresh water.
Circulate aqueous solution containing 5% citric acid or 5% oxalic acid at 30°C
to 60°C for 30 to 60 minutes.
* Adjust cleaning time so as to obtain an appropriate cleaning effect.
Perform flushing for 20 to 40 minutes to completely replace detergent with fresh water.
Perform flushing for 20 to 40 minutes to completely replace detergent with fresh water.
Circulate aqueous solution containing 5% caustic soda at 30°C to 60°C for 30
to 60 minutes.
* Adjust cleaning time so as to obtain an appropriate cleaning effect.
Depending on your conditions of use, such as evaporator, condenser, oil cooler,
or food equipment, provide processes such as a drying process, disinfection
process, and sterilization process.
Precautions in Cleaning
Points to Note in Cleaning
●
For precautions in cleaning BHE, read "Safety Precautions" (pages 3 to 5).
●
In order to improve the cleaning effect, the cleaning flow rate should preferably be as much
as possible. (Recommended flow rate: 1.2 times or more than operating flow rate)
●
The cleaning-in-place (CIP) is normally performed by combining "acids" and "alkalies".
However, depending on your conditions of use, only the chemical which has s higher
cleaning effect may be selected.
Pressure Test and Leak Test
●
For precautions in performing the pressure test or leak test of BHE, read "Safety Precautions"
(pages 3 to 5).
10
