Product Handbook 2026 - Volume 1

Boiler house TDS blowdown controls

2

Requirements Many countries ensure the protection and safe operation of boiler equipment, buildings and personnel through Legislation and Standards. For example shell boilers operated in the European Community must comply with requirements of the harmonised standard EN 12953 that specifies maximum contamination levels for boilers operated unsupervised for periods of 24 or 72 hours.

Function To protect the boiler feedwater system from oil and grease contamination, the Turbidity Monitoring System has two independent alarm set points: - Alarm 1 can be set to divert and discharge contaminated water above 3.0 ppm to a blowdown vessel or directly to drain. - Alarm 2 can be set to shut down the boiler if contamination level rises above 5.0 ppm. Diversion of contaminated supplies may be achieved with two 2-port ball valves with a ¼ turn actuator or a 3-port actuated valve.

Spare parts For available spares and options please contact your local Spirax Sarco representative.

2.4 20

Technical data TF56-N Turbidimeter Material

Sensor body stainless steel 316 Ti, 1.4571

Line size

DN25

Process connection

DIN flange (EN 1092)

Gaskets

Viton seals

Windows

Sapphire

Optical path length

40 mm

Process pressure

10 bar

Continuous process temperature

0 ° C to +100 ° C (+32 ° F to 212 ° F)

Peak process temperature

+120 ° C (+248 ° F) for maximum duration of 15 minutes / day

Ambient temperature

0 ° C to +40 ° C (+32 ° F to 104 ° F)

Air purge

Connections available as standard

Light source

Incandescent tungsten lamp: 5.0 Vdc, 775 mA (typical life span 3 to 5 years)

Wave lengths

400 nm – 1100 nm

Detector

Silicon photodiodes hermetically sealed

Calibration

Basic calibration in ppm (DE), FTU, EBC

- 0 - 25 to 500 ppm (DE) - 0 - 10 to 200 FTU - 0 - 2.5 to 50 EBC

Any measuring range between

Measuring range

Resolution

< ± 0.5% of respective measuring range

Repeatability

< ± 1% of respective measuring range

Linearity

Specific to application, < ± 2% with standard solution

Protection

All optical parts protected according to IP65

Cable length

5.0 m (16 ft)

VA-plug-protection

Special ultra-shielded cable sets

Certificates

ISO 9001:2000, PED, CE, HPO

TI-P403-96 AB Issue 3

Page 2 of 5

Model 556 / TF56-N Turbidity Monitoring System

Powered by