Globe valve/gate valve question?

[JOB6]

Hi everyone, what is the difference between a gate valve and a globe valve? I was looking at pictures and they look the same although I think the one on my bathroom which his over 40 years old is done in and needs replacing thanks.

 

[Nozzle]

A gate valve has a part which slide into the flow perpendicularly. It relies on pressure on one side to seat it against the seat and can be difficult to open against pressure. A globe valve seats in the direction of the flow (the flow is forced to change direction in the valve body). It also use the pressure of the system fluid to help it seat, only this time the seat can be shaped to make it seal better, as the valve seat doesn't have to slide over it, but engage into it instead.

Nozzle

 

[JohnD]

the gate valves are often used as service valves on big pipes because, when fully open, they don't restrict the flow. They may not give a perfect seal when shut, so are not used as stopcocks, but some big ones are machined slightly wedge-shaped to improve the seal. It's very common to find them seized, especially when they have been screwed hard open, instead of eased shut half a turn as they should be.