exit velocity\"s

steve_6

Or does the near boiler piping equal everything out as far as making " dry steam" goes. If not , then Weil McLain and H.B. Smith are blowing everybody away with their 3 inch supply tappings. Their exit velocities are better than 50% slower from most other boilers.

Gary Fereday

Velocity compares to speed and lift just like an airplanes wing.

the lower the velocity the less it picks up!

Tony Conner

When Steam Bubbles...

...break the water surface inside a boiler, they throw up water droplets. This happens in every steam boiler - there's no escaping it. Large industrial boilers have a steam space between the water level, and the steam outlet connection. The bigger the space, the drier the steam, because the water droplets can just drop out by gravity. Many industrial boilers have separators & screens (drum furniture) to dry the steam further, or to allow the manufacturer to use a smaller diameter (and cheaper) steam drum. Surface area of the water has an effect as well. The bigger the surface of the water, the better the steam quality. But if your boiler gets too big, and therefore too expensive, nobody will buy it.

Boilers with low water content relative to how much steam they can generate, and small surface area for the steam bubbles to pop through, can have steam quality problems. The lower the steam velocity, the more water droplets can fall out. This is why they usually have fairly large steam connections off that type of boiler, as compared to a conventional boiler with a lot of water in it. Think of the steam velocity and water drops as fallen leaves on a windy autumn day. If there's not much wind, the leaves don't go very far. On a windy day however, the leaves that were in your lazy slob of a neighbour's yard, are now in yours. Water droplets in a steam "wind" will behave the same as leaves.

For a given load, the bigger the pipe, the lower the steam (or any other fluid) velocity.

steve_6

do youknow the answer to the question?

does the near boiler piping level the playing field of smaller lwc residential boilers, or not? thanks

Steamhead

If near-boiler piping is done right

the header will catch whatever water comes up from the boiler and send it down the equalizer, where it will return to the boiler.

That said, larger steam tappings are always better. However, some manufacturers get around this by providing more than one tapping. In this case, the installer must use every available tapping.

The bottom line here is- RTFM (Read the freakin' manual) and follow the instructions when piping the boiler!

Here are two properly piped boilers. The first is an oil-fired Burnham, with one 3-inch tapping. The header on this one is also 3-inch.

The second one is a gas-fired Columbia with 2 2-inch tappings. These are brought together into a 2-1/2-inch header.

These were both piped according to the manufacturer's specifications, and they run perfectly.



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Tony Conner

Yes...

... I do.

[Deleted User]

i like that leaf analagy

im going to have to use that one.