Sample SWAS

Analytical Application Sets Continuous emission monitoring

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Today in power plants, high pressure boilers and steam turbines are under constant attack from erosive and corrosive elements such as Silica, Sodium, Dissolved Oxygen, Calcium, Chloride and Phosphates. Without accurate measurement and monitoring, the plant may suffer heavy mechanical damages that can be caused due to imbalance of turbines, reduced efficiency, deposition on turbine blades, corrosion of steam pipe work and so on.


  • Sampling and analysing systems
  • Engineering complete system solutions.
  • Equipped with state-of-the-art-measuring technology.
  • High functionality and service life.
  • Head start in know-how through 70 years of experience and innovation.


Starting with a mounting open frame-free standing Wet Rack with sample preparation system, it is possible to add additional units as options. These include:

  • High-pressure needle valves
  • High-pressure sample coolers.
  • Pressure conditioning.
  • Pressure safety valve.
  • Safety shut-off valve
  • Second sample cooler for chilled water.
  • Temperature switch.
  • Flow indicator.
  • Filtration.
  • Cation exchanger in case of measuring cation conductivity.
  • Analyzers.
  • Chiller unit.
  • Alarm panel
  • High-pressure needle valves

    NW 6 mm, 400 bar, 630°C

  • Shut-off valves
  • Blow valves
  • Pressure-reducing valves
  • Fine-regulating valves
  • Shut-off valve units
  • High-pressure sample coolers

    For boiler feed water and steam, design according to VGB/DGRL, alternatively ASTM. Made of high-quality stainless steel, sample coolers for temperatures up to 600°C and pressure up to 400 bar, sample flow up to 100 kg/h

    Pressure regulator valve

    Three different seat materials, three alternate orifice sizes and 7 pressure control ranges with INCONEL® diaphragms offer the user a wide spectrum of capabilities for pressure control with inlet pressures up to 6000 psig and standard operating temperatures up to 500° F (260° C).

    Safety shut-off valve

    The purpose of the Auto Safe is to protect the down-streamed analyzing system in the sample flow and personnel against extremely high thermal loading (loss or lack of cooling water) (mechanically or electrically actuated).

    Second sample cooler for chilled water.

    The tube-within-a-tube design also provides for high pressure/temperature capabilities on both sides of the heat exchanger, providing greater application flexibility. The single continuous inner tube increases reliability and cleanliness and allows the unit to be completely drainable. The second sample cooler is used with chilled water to reach temperature of sample in 25°C in according to ASME standard for SWASystem.

    Chiller unit

    Maintain sample temperature to 77°F (25°C) with water-cooled

    temperature control unit or a closed-loop cooling water isolation skid.

    Frame-free standing Wet Rack

    Stand-alone frame with painted carbon steel construction suitable for indoor installation. Fabricated pre-wired in PSQ work shop with sample preparation.

    Power supply

    The system can be designed either for 115 V AC, 230 V AC or 400 V AC (-15 %, +10 %) with 50 or 60 Hz. Three phases, neutral and ground must be provided by the customer at 400 V AC.


    Sampling and analyzing system with analyzers of well-known suppliers:

    Hamilton, Knick, Emerson, Dr. Thiedig

    For all typical measuring tasks as Cond., pH, O2, Na, SiO2, N2H4 etc.

    Completely wired on control panel as interface to the DCS.

    pH and conductivity

  • Two wire is the simplest transmitter. These analyzers are directly loop powered by +24V DC supply from DCS and PLC
  • Also direct 110-230 V AC powered transmitter is available if alarm contacts are required along with 4-20 mA output. Separate PT-100 sensor input can be used for temperature compensation for measurement.
  • parameter

    measuring range

    Temperature sensor


    0 – 14 pH



    0.02 to 2000 µS/cm



     Dissolved oxygen

    Dissolved oxygen monitoring is imperative in power stations using neutral or combined operating conditions (pH 7.0-7.5 or 8.0-8.5). The typical points in steam circuit where dissolved oxygen monitoring is required are deaerator inlet and outlet.


    measuring range

    Temperature sensor


    1 ppb to 40 ppm

    NTC 22 kOhm

    Degassed Acid Conductivity

    Acid conductivity

    In cation filter, the H+ from the exchanged cations combine with OH- from alkalizing agents to water. The remaining conductivity is determined by the autoprotolysis of the pure water plus the impurities in the form of anions, i.e. also CO32-. To operate a steam turbine, the acid conductivity must not exceed a threshold of typically 0.2 µS/cm. The following causes for increased conductivity are possible:

  • unclean piping system, high corrosion conditions
  • cooling water leakage in the condenser
  • atmospheric air-in leakage with CO2-impact
  • organic substances in the boiler feed water - CO2- impact after heating
  • Degassed Cation conductivity

    For the shortest possible start-up phase, the acid conductivity must be measured without the influence of the conductivity caused by dissolved CO2. Thus the threshold for operation of the turbine is reached faster. The dissolved CO2 rises up the conductivity, but does not harm the turbine. Therefore, it is necessary to remove the carbonic acid from the sample and to measure the conductivity again (degassed acid conductivity).


    Digox 6.1 HY-S

    measuring range

    Conductivity 0 – 1000 µS/cm, pH calculation from 7.5 - 10


    < [1 % of measuring value + 0,015 µS/cm]

    Silica (SiO2)

    The determination of dissolved silicic acid (ortho-silicate) in the water steam cycle is of great importance for the operation and plant safety in power plants. In addition to the determination of ortho-silicate in the live steam in order to avoid deposits or crystallisation inside the turbine, it is possible to detect an aperture in the anion filter or mixed bed exchanger.


    Digox 602 silica

    measuring range

    0 – 5000 ppb SiO2


    precision photometer with temperature control of the sample


    Max. {± 2 % of reading or ± 2 ppb} within measuring range 0 – 100 ppb

  • Very low reagent consumption, one reagent set (approx. 3 liters) lasts for 8 weeks at maximum measurement frequency
  • Multi stream


          Sodium (Na)

The determination of sodium in low concentrations in the water-steam cycle is of great importance in power plants. On the one hand, this is due to the fact that the significance of sodium in corrosion processes has become more and more recognized over the last few years. On the other hand, this measurement procedure enables a fast monitoring of a leakage for instance in the condenser or the aperture in a cation filter or a mixed bed filter.




Digox 602 sodium

measuring range

0.1 – 2000 ppb Na

Measuring principle

potential measurement of an ion-sensitive Na-electrode against a reference electrode


Maximum {±2 % of reading or ±2 ppb}

  • Very low consumption of conditioning materials: a maximum of 0.5 l DIPA/month at pH 7
  •  Multi stream


  • Technical Specifications 

    Climatic conditions                                             

    Ambient temperature                              0 ... 35 °C                                                                   

    Relative humidity                                     70%, non-condensing                                         

    Corrosive atmosphere                            No                                                                     

    Sample inlet conditions                                            

    Max. Sample pressure at inlet to             400 bar                                  

    sample preparation system                                                                           

    Max. Sample temperature at inlet to        550 °C                                                                  

    sample preparation system                                                                                                                                               

    design pressure                                      245 bar at 550°C                                                                 

    Sample flow [kg/h]                                   60                                                                     

    Medium                                                   Steam or liquid     


Tube material                                          SST or CS                                   

Cables                                                     Not armored, not halogen-free                                      

Electrical design                                      According to IEC                  

Cable ID                                                  Individual core labeling as                                 

System design                                                                   

Ex zone                                                   Non-hazardous                          

Version                                                    Mounting frame                    

Automatic calibration                               Yes(just for sodium and silica)                                   



Dimensions (without plinth)                                       

Size                                                         Depended on quantity of stream                                                                


               More information in the catalog link above

Order request form

To complete the order, complete the form below :

Main Office

(98) 21 44443999 داخلی 116
(98) 21 44444950 داخلی 116
145 Shahid Mokhberi St. Sattari Hwy.,Tehran, Iran

Piramoon System Qeshm

(98) 76 35340394

Tula Industrial Park, Cable site

Downtown Office

post box : 567-14455
postal code : 1475877134
145 Shahid Mokhberi St. Sattari Hwy.,Tehran, Iran