Sampling systems are designed to decrease the temperature and pressure of sample water safely and feed it to the water quality analyzer.

Sampling systems are units that supply sample water extracted from systems in the boiler plant to the water quality analyzers after decompression, cooling, flow adjustment and isothermalization. Installing water quality analyzers allows monitoring of the water quality of the systems in the plant. Our sampling system supplies the high-temperature, high-pressure sample water to the water quality analyzers after cooling, decompression, securement of constant flow, and isothermalization with Nikkiso-specific know-how, properly and safely. A wide variety of water quality analyzers are used according to the target water quality.


  • This system automates the water quality monitoring of boiler plants. During normal operation, it can operate the devices sequentially according to plant processes such as the start-up and shut-down of the plant.
  • Concurrent use of a chemical injection system allows for automization of plant water conditioning. It can automize water conditioning, not only during normal operation but also at the start-up and shut-down of the plant during which operators bear a great burden.

Main installations

  • Thermal power plant
  • Nuclear power plant
  • Geothermal power plant

Consideration in design

Handling high-temperature, high-pressure sample water, the sampling system requires special care in terms of function and safety. Thermal fatigue associated with increased start and stop of the plant and other various fatigue phenomena are expected, and measures against these phenomena have been taken in determining the piping routing, connection method, and material selection. We also test various structures and piping methods to collect sample water at a constant flow rate over a wide pressure range from plant start to maximum load.

Product Lineup

Geothermal steam on-line monitors

Geothermal steam on-line monitors are systems that perform on-line measurement of the water quality and amount of gas in the main steam in geothermal power plants.
In geothermal power generation, a turbine is driven by underground steam generated by the thermal energy from volcanic activity to generating electricity. Geothermal power generation is expected to contribute to the prevention of global warming as a high-potential method for generating clean energy without using fossil fuel. Currently, some 300 units (8.88 million kW) worth of geothermal power are being generated at plants around the world.

Main features

  • Six items necessary for plant control are measured.
    • Silica concentration
    • Chloride ion concentration
    • Noncondensable gas concentration
    • pH
    • Electrical conductivity
    • Acid conductivity
  • Capable of performing unattended operation.
  • Removes hydrogen sulfide contained in the sample water automatically.
  • Removes carbon dioxide (CO2) contained in the sample water automatically.
  • No maintenance is required except for once monthly maintenance.