31.5.2011 | In engineering practice we often meet operational requirements and conditions that are almost contradictory or cover an extreme wide range of operating values.
One of such application is a special boiler armatures, such as boiler feed valves. For these valves is specific high value of the nominal flow rate at minimum pressure difference in the standard operating condition of the boiler (flow of condensate into the boiler).

Once this equipment has to perform the function of start-up valve, operating conditions are exactly opposite. Condensate from output of feed pumps (high pressure) should be gradually (minimum flow) supplied into the boiler drum, where the starting pressure is very low.

For such conditions, our engineers developed a special valve, which fulfills both mentioned functions.


  • Body casting from alloy steel G17CrMo9-10 (1.7379), self-tightening bonnet.
  • Main plug controlled by auxiliary pilot plug, supply of medium over the cone
  • Multi-step pilot plug allows the small flows at high pressure drop without risk of cavitation. The first half of opening is the Main plug designed as double-step, with throttling elements (cages).
  • Simultaneously with a higher opening of the valve, the internal throttling reduces and this way the function of boiler feeding with low pressure drop is securing.
  • The seat with protecting cage.
  • Extreme closing tightness.
Control valves with such design were used e.g. in Power Plant project in Hungary, when the operating parameters were:
Boiler start-up: dP= 140 bar flow Q= 1,8 kg/s
Full operation: dP= 25 bar flow Q= 23,61kg/s

If such design interested you, don't hesitate to ask more details on, or contact us directly by phone +420 558 321 088.

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