During the first stages of my steamboat project I was very concerned about the reported, frequent failures of the feed-water non-return valves. As a result, I purchased 4 high-quality, stainless clack-valves for the projected installation. The following picture shows the Hypro pump, the damper, the pre-heater and the feed line with the clack valve:
After several years of operation, the initial clack valve is still there... An inspection carried out some days ago showed no signs of wear. One of the reasons for this long endurance could be the fact that, during operation, this non-return valve does not clack...
Concerned about the high-amplitude feed-water pressure pulsation observed on some boats (at the beginning you are concerned about anything...), I decided to install a large damper at the discharge side of the Hypro twin piston pump. If the air pressure on top of the damper diaphragm is adjusted to the correct value, the resulting feed-water flow shows just a very slight pressure ripple. Hence, as soon as the pressure in the feed line reaches the boiler pressure, the clack valve opens to allow for the resulting flow... and remains open. No clacking whatsoever !! The valve safely closes as soon as the bypass valve to the hotwell is openened. On the other hand, a loud clacking can be perceived when using the manual feed pump.
What do you fellows think about it? An April Fools' Day hoax?
Albert
