To improve the efficiency of a steam boiler system, feed-water flowing from the feedwater tank to the boiler, is preheate by a heater. The heater is a heat exchanger with tubes containing feed-water. From the outside, the tubes receive steam drawn-off from the turbine. In the case of a leakage in the tubing system, water of higher pressure rushes into the vapor room of lower pressure.

To avoid any damages by

• penetraton of feed-water into the turbine
• build-up of inadmissible pressure in the heater jacket

the heater must be separated from the feed-water pressure tube as soon as possible. This will be provided by the heater protection unit, i.e. by quick choosing valves which are controlled by their own medium and located at the in- and outlet of the heater. Usually a change-over valve is located at the inlet and a stop valve is located at the outlet.

3-Way change over valve is a quick acting valve and is located at the inlet of preheater protection unit. Preheater protections avoid any damages by penetration of feed-water into the turbine and build-up of inadmissible pressure in the preheater jacket.

 Change-Over-Valve.pdf

A quick closing valves as 2-way or 3-way design is located at the outlet of a preheater protection unit.

 Quick-Closing-Valve.pdf