Water valves

[Ed from chicago]

Can someone tell me if the following valves are interchangable: ball valves, gate valves, metal sillcock, globe valve, hose bibs.


Thanks

[hj]

What do you mean by "interchangeable"? In line valves perform the same function, but have features that make them the valve of choice in certain situations. Hose end valves are "interchangeable", if all you want to do is turn a hose on or off.

[Ed from chicago]

I'm sorry, I guess I worded my question incorrectly...can a boiler valve, a sillcock, and a hose bib be used in the same purpose...say as a lawn faucet? Is there any difference in the use of a globe valve, gate valve and a ball valve?

Thanks

[jimbo]

All valves will allow flow or block the flow. However, different types are optimized for different applications.
-gate valves should be full open or full closed. They should not be used to throttle flow. Also, they are know to allow at least a few drips to flow by in the closed position when used as the main shut-off in a residence.
-globe valves usually have a rubber washer and seat for complete shut off; the rubber needs frequent replacement. Also, the passage through a globe valve is small ( and turbulent) .
-ball valves can be full port, and ball seats are very reliable and long lasting. Ball valves are also full open/full closed. Not for flow control.
-hose bibb defines the connections: one end connects to house pipe but the other end has hose threads. Also, the outlet is angled for ease of hose connection. Sillcock just another type of hose bibb.


This is just a brief discussion of the vast topic "valves".

[hj]

Hose bibb, boiler drain, and sill cock only differ in whether they have a flange to seal against the wall and the angle the hose threads make with the valve body. Gate valves and ball valves are "always open" or "always closed" valves and are not intended to operate partially open or closed. A glove valve can be used for throttling service but introduces pressure loss if used as a main line valve.

[Ed from chicago]

Hj & Jimbo,

Thanks for the excellent definitions, and explanations. This is a great place.

Ed :)