In fossil and nuclear energy generation, as well as in modern solar power plants, the steam circuit pumps are the core of the system, especially the boiler feed pumps. These power plant pumps must be protected against (severe) damage caused by vibrations, cavitation on the suction side, and partial evaporation of the medium due to overheating if the flow rate falls below a minimum. That is the job of the Schroeder Automatic Recirculation Check (ARC) valve.
The boiler feed pumps in gas (CCPP) and biomass power plants pose a particular challenge. Among other things, these systems are increasingly used to compensate for the natural load fluctuations from wind and solar energy use.
The associated load changes lead to longer operating phases with heavy partial loads, i.e., very low process flow rates.
This means longer operation with a partially open bypass for the minimum flow valve, which is associated with considerable wear and tear. For this operating mode, special minimum flow valves are required that can withstand the resulting loads. These are the Schroeder SIP and SHP series.
Alternative areas of application are descaling systems in steelworks, injection pumps for the exploitation of oil and gas reserves, process pumps in the chemical and petrochemical industry, and heat transfer pumps in solar power plants.
Used to protect pumps and installations, Schroeder automatic recirculation valves help guarantee plant safety.
Operating principle
ARC valves are mounted on the discharge branch of the pump or in the pressure line right after the pump. The bypass branch of the valve is connected to the bypass line. The valve operates on demand flow. In start-up conditions with no demand flow to process, the valve will allow the minimum continuous flow through the bypass.
As the process demand is opened, the valve will modulate flow between the process and bypass branch. As the process demand exceeds the minimum continuous flow, the bypass will fully close and all flow through the valve is sent to process. If the actual process flow rate falls below the required minimum flow, the valve automatically opens the bypass line, and the determined flow rate can be discharged through the bypass.
The ARC valve ensures that the total pump flow rate (process flow plus bypass flow) is always higher than the required minimum flow. In this scenario, the pump is always protected from low flow conditions.
Schroeder’s 100 per cent quality guarantee
Quality is a top priority for Schroeder Valves. Schroeder only uses premium components and materials and has developed a state-of-the-art test facility where every valve is subject to a 100 per cent pressure and functionality test before delivery. All flow related data is recorded and stored in a database for future reference.
A reliable solution
The ARC valve ensures that the pump never works below the minimum flow. As mentioned above, this prevents damage from vibrations, cavitation on the suction side, and partial evaporation of the medium due to overheating.
The Schroeder Valves portfolio ranges from throttles to one-way check valves to high-pressure control valves. Each valve from Schroeder Valves is designed specifically for the customer’s pumps and system data, and undergoes a 100 per cent pressure and functionality test prior to despatch.
This partner content is brought to you by IndustriTech. For more information, contact the Australian distributor, www.industritech.com.au.
