G Scale Model Train Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
could any one post a sketch of what goes on inside a bypass valve? has any one successfully

constructed one? I have an axle pump from an aster that I would like to install on a PLM 231.
Thanks for any help.

Morgan
 

·
Registered
Joined
·
101 Posts
A bypass valve is just any water valve. It is placed after the axle pump before the boiler check valve. When open it lets the water from the pump circulate back to the tank. When closed the pump pressure overcomes the check valve pressure and the water enters the boiler.
 

·
Registered
Joined
·
39 Posts
A "bypass" valve is just an on-off valve, nothing more than that, and it can be either a quick on-off, like a ball cock, or a conventional stem valve. What happens is the pump works all the time and the pumped water is piped so as to be able to go one of two ways, . . . to the clack valve and into the boiler, or return to the tender tank. Given the choice of whether to try to overcome boiler pressure and pass through the clack, or return unobstructed to the tender, the water will always take the path of least resistance and return to the tender, unless you obstruct its path to the tender with a valve (the by-pass valve.) Then the path of least resistance is through the clack and into the boiler. So a by-pass valve is simply on-off, or anything that will shut down the water return path to the tender.
 

·
Premium Member
Joined
·
5,510 Posts
Posted By Old Boy on 02/14/2009 4:48 PM
A "bypass" valve is just an on-off valve, nothing more than that, and it can be either a quick on-off, like a ball cock, or a conventional stem valve. What happens is the pump works all the time and the pumped water is piped so as to be able to go one of two ways, . . . to the clack valve and into the boiler, or return to the tender tank. Given the choice of whether to try to overcome boiler pressure and pass through the clack, or return unobstructed to the tender, the water will always take the path of least resistance and return to the tender, unless you obstruct its path to the tender with a valve (the by-pass valve.) Then the path of least resistance is through the clack and into the boiler. So a by-pass valve is simply on-off, or anything that will shut down the water return path to the tender.



Yep, Like this:
 
1 - 6 of 6 Posts
Top