Miura prioritizes a calculated blowdown ratio and uses the conductivity sensor as a backup limit. Do not set the timer ratio to zero and rely only on instantaneous conductivity.
Calculation
Cycles of concentration = target boiler-water conductivity / feedwater conductivity.
Blowdown ratio (%) = 1 / cycles of concentration x 100.
EXAMPLE: Target 4,000 µS/cm and feedwater 200 µS/cm gives 20 cycles and a 5% blowdown ratio.
- Target boiler-water conductivity is generally 2,000 to 4,000 µS/cm, subject to chloride and other chemistry limits.
- Maintain at least 50 µS/cm where required for reliable water-level probe output.
- Conductivity sensor reading may vary by ±15% from a manual meter.
- Default surface-blowdown backup threshold is 3,500 µS/cm and can be adjusted in 500 µS/cm increments.
- Maximum design blowdown ratio is 20%, equal to a minimum of five cycles. Feedwater above 500 µS/cm should be evaluated for Reverse Osmosis; above 800 µS/cm is outside the design conditions for a 4,000 µS/cm target.
- Auto bottom blowdown backup threshold is listed as 5,000 µS/cm.
Sampling
- Use a sample cooler.
- Sample at a stable firing stage.
- Ensure the feedwater pump is not running.
- Follow hot-water sampling safety practices.
Comments
0 comments
Please sign in to leave a comment.