Discharge control valves are used to discharge (boiling) water from the boiler drum during start-up or low-load operation. On Benson boilers, the valve is used as a start-up valve to ensure the (boiling) water level in the start-up drum remains constant. The water can be returned to the cycle in three different ways:

1. via the circulation pump and the circulation control valve
2. via the expansion unit at atmospheric pressure
3. into the feedwater tank

Forged valves in angled form, with welded studs as per DIN, ANSI or other standards. Outlet 2–3 sizes larger than the inlet due to evaporation. A hardened sleeve protects the seat outlet from erosion.

• No cavitation
• No erosion
• No oscillation or vibration
• Long service life
• Precise characteristics
• Easily replaceable interior parts for simple maintenance

Low-load start-up control valves supply the boiler with the required quantity of feedwater during start-up (30–50% of the water required for full-load operation), regulated by volume, at higher pressure differences than at full load. They must also be able to safely handle smaller volumes at higher pressure gradients and large adjustment ratios. The same requirements arise during low-load operation.

Forged valves in straight, angled or Z form, with welded studs as per DIN, ANSI or other standards.

•  No cavitation
•  No oscillation or vibration
•  Long service life
•  Noise <85 dB(A)
•  Precise characteristics
•  Easily replaceable interior parts for simple maintenance

Circulation control valves regulate the flow rate during drum circulation on forced-flow steam generators.

Forged valves in straight, angled or Z form, with welded studs as per DIN, ANSI or other standards.

•  No cavitation
•  No oscillation or vibration
•  Long service life
•  Noise <85 dB(A)
•  Precise characteristics
•  Easily replaceable interior parts for simple maintenance

Injection control valves are primarily flow control valves, which means they supply the required amount of cooling water to the point of use. The pressure at the point of use can vary greatly and the pressure gradient at the injection or cooling water control valve can therefore strongly fluctuate at a constant upstream pressure. Therefore, most injection and cooling water control valves have a logarithmic opening characteristic. This ensures a largely linear flow characteristic. Valves used for steam generators are in constant operation.

Single or multiple stage version:

Forged valves in straight, angled or Z form, with welded studs as per DIN, ANSI or other standards.

Single stage version

•  Adapted to prevailing operating conditions
•  No cavitation
•  No oscillation or vibration
•  Long service life
•  Noise <75 dB(A)
•  Precise characteristics
•  Easily replaceable interior parts for simple maintenance

Multiple stage version

•  Graduated pressure reduction
•  Adapted to prevailing operating conditions
•  No cavitation or erosion
•  No oscillation or vibration
•  Long service life
•  Noise <75 dB(A)
•  Precise characteristics
•  Easily replaceable interior parts for simple maintenance

One of the functions of condensate (level) control valves is to control the level of accumulated condensate and discharge it to the main or auxiliary condenser. Different types of installation mean that the requirements can be easily met without needing special versions of the valves. However, evaporation and cavitation are often unavoidable on HP and LP preheaters with operating temperatures close to the saturated steam curve, and when the condensate is returned to the main and auxiliary condensers.

Forged valves in straight, angled or Z form, with welded studs as per DIN, ANSI or other standards.

For boiler feed pumps and condensate pumps, the flow rate may not fall below a certain minimum level. This would lead to excessive heating of the feedwater or condensate inside the pump and incipient cavitation. In certain boiler modes – start-up, variable pressure operation or low load operation – the volume required is less than the minimum pump flow. By returning the difference in volume to the feedwater tank or condenser via a pump bypass system consisting of the minimum flow unit including the minimum flow valve, the required pump protection is ensured. The minimum flow valve thus acts as a pump safety valve.

Forged valves in angled or Z form, with welded studs as per DIN, ANSI or other standards

•  No cavitation
•  No erosion
•  No oscillation or vibration
•  Long service life
•  Noise <75 dB (A)
•  Precise characteristics
•  Easily replaceable interior parts for simple maintenance
•  Failsafe technology: valves open in the event of power failure

Feedwater control valves regulate the feedwater flow to the steam generator. Because there may be several different types, the concepts are also different. Full-load control valves are installed in the main feedwater line. They are designed for the full feedwater volume of the steam generator and should produce as low a pressure gradient as possible. With drum boilers, the valves must regulate the water level for the drum, and for speed-controlled feed pumps, they must regulate the differential pressure. For forced-flow boilers, flow control is mainly required for the low flow range if the feedwater pumps cannot supply a lower flow rate. For start-up, shutdown and low-load operation, the valves must be able to handle large pressure differences at low feedwater flows.

Cast or forged valves in straight, angled or Z form, with welded studs as per DIN, ANSI or other standards.

•  No cavitation
•  No oscillation or vibration
•  Long service life
•  Noise <75 dB(A)
•  Precise characteristics
•  Easily replaceable interior parts for simple maintenance