Also please tell me why globe valves are preffered for Landing valves in wet risers in firefighting and gate valves in dryrisers..
2006-10-09 23:27:50 · 6 answers · asked by HAREESH M 1 in Science & Mathematics ➔ Engineering
Thanks for all answers.. However I think a ball valve and a globe valve are different.
2006-10-09 23:59:36 · update #1
A gate valve has a wedge of material which cuts across the flow area and seats around the circumference (or near the circumference) of the pipe.
A globe valve diverts the flow at right angles (or sometimes 45 deg to allow for external shaft drive) through a circular opening and the flow is checked or controlled by a circular disc which moves towards and ultimately seats on the bevelled edges of the circular opening. (for diagram see http://www.goddardvalve.com/270.htm ) You are right it is different from a ball valve.
I don't know the details of firefighting systems but a gate valve is normally used for shutoff applications and a globe valve for throttling or flow control.
2006-10-10 03:07:55 · answer #1 · answered by Robert A 5 · 1⤊ 0⤋
Well, we're all around it. I like the answer the gate valve is like a garage door. That is about right. A globe valve the flow through the valve is forced through two 90 degree turns and the valve shuts off like a lid coming down in between the two turns.
Not sure why the fire requirements are that way.
2006-10-10 06:34:05 · answer #2 · answered by Roadkill 6 · 0⤊ 0⤋
Robert A has a pretty good answer.
A point of clarification. Gate and globle valves can be manufactured of various materials from steel to plastic.
I am not sure what a landing valve is but I would expect most valves in a fire fighting system to be gate valves. As previously stated, gate valves are typically open or closed and globe valves are used for controlling flow. You need to view their function in this light in trying to understand why one or the other is used in a fire fighting system.
2006-10-10 03:28:42 · answer #3 · answered by oil field trash 7 · 0⤊ 0⤋
A gate valve is like a garage door. A globe, typically called a ball valve, is round with a hollow center and two (open / close), three (open / close in multiple directions) or sometimes four (open / close in multiple directions where one direction is always flowing when valve is open) side openings.
2006-10-09 23:38:55 · answer #4 · answered by MRR 1 · 0⤊ 1⤋
agate valve has brass disc that slowly screws down in place or in seat.
a globe or ball valve ia a brass or steel ball that has a cilindrical hole through the center and it is rotated from open to closed by turning the handle 90 degrees.
ball valves operate more quickly
2006-10-09 23:34:20 · answer #5 · answered by gussie r 3 · 0⤊ 1⤋
a ball valve has a sphere that closes, a gate valve has a flap
2006-10-09 23:37:30 · answer #6 · answered by Anonymous · 0⤊ 0⤋