Globe versus Ball & Gate valve
Globe versus Ball & Gate valve
(OP)
Between Globe,Ball,and Gate, which type of valve is capable of maintaning Differential Pressure better?
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Globe versus Ball & Gate valve
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Globe versus Ball & Gate valveGlobe versus Ball & Gate valve(OP)
Between Globe,Ball,and Gate, which type of valve is capable of maintaning Differential Pressure better?
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RE: Globe versus Ball & Gate valve
I suspect you mean throttling though.
Valve Magazine had/has a series called "Back to Basics" which covers this. Otherwise, "Valve Selection Handbook" by Smith and Zappe (ISBN 978-0750677172) is a good resource.
- Steve Perry
http://www.linkedin.com/in/stevenhperry
This post is designed to provide accurate and authoritative information in regard to the subject matter covered. It is offered with the understanding that the author is not engaged in rendering engineering or other professional service. If you need help, get help, and PAY FOR IT.
RE: Globe versus Ball & Gate valve
You can get some pressure differential at nearly closed positions with the other valve types, but too close to fully closed to do you much good. They will also be subject to erosion and filling the seal areas with dirt when in that position. It's by far better to use those types of valves in Open or Closed Positions only. Some patterns of plug valves and butterfly valves would be more effective for throttling, if for some reason you don't want to use a globe type.
"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.
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RE: Globe versus Ball & Gate valve
Download the free Fisher Control Valve Handbook from the Emerson web site for a primer.
RE: Globe versus Ball & Gate valve
StevenHPerry, No doubt all of the valves can provide dp across at closed position. Your guess is nearly right. I mean capability of maintaning dp across at Fully opened position.
BigInch & JLSeagull, I agree with you that the globe is well suited for throttling purpose. But what about the ON/ OFF control purpose? For example, in the case of on/ off drain liquid from the high pressure system to the low pres. does the ball work as well as globe? or which of them is preferred?
JLSeagul, is there any reason to prefer using of the segmented ball or butterfly compared to the globe in the case of above NPS 6?
RE: Globe versus Ball & Gate valve
Typically balls are easier to operate taking only 1/4 turn O/C. Gates can take many, many more full turns to O/C, but gates can be even cheaper than balls, so make your decision according to cost, or ease of operability for those applications that only need an ON/OFF function.
"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.live.com
RE: Globe versus Ball & Gate valve
Depending on the sizes and pressures involved, you might be better off with a stop valve and an orifice downstream of the valve.
For an all-in-one, a globe valve is your best bet. The Cv should be low. Here's a good page to compare the relative Cvs of forged (small bore) valves:
http://
At 2" size, the globe will have ~9x the pressure drop of a reduced port gate valve.
- Steve Perry
http://www.linkedin.com/in/stevenhperry
This post is designed to provide accurate and authoritative information in regard to the subject matter covered. It is offered with the understanding that the author is not engaged in rendering engineering or other professional service. If you need help, get help, and PAY FOR IT.
RE: Globe versus Ball & Gate valve
For on/off "control", an actuated ball valve gives more predictable results than the globe valves with diaphram operators that are often used for dump valves or wellsite ESD valves. I've done the accident investigation on at least 3 fires that the root cause was a diaphragm operated globe valve in on/off service (as a spec break) that leaked through and over pressured downstream equipment. This is common practice in Oil & Gas, and it is a bad practice.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Globe versus Ball & Gate valve
"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.live.com
RE: Globe versus Ball & Gate valve
RE: Globe versus Ball & Gate valve
RE: Globe versus Ball & Gate valve
"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.live.com
RE: Globe versus Ball & Gate valve
I'll add that I have a practical dislike of gate valves due to their sensitivity to debris. They can jam in some part-closed position due to debris and thereby fail to accomplish their intended purpose.
Using a gate valve for throttling is a practical absurdity. All that will be accomplished is the rapid damaging of the sealing surfaces.
In very clean services, gate valves can provide good shut-off performance with increasing upstream pressure increasing the forces on the sealing surfaces. This can result in greater actuating force requirements.
Because of their sensitivity to the accumulation of debris, I would never install a gate valve in a horizontal line with its stem in a horizontal orientation.
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.
RE: Globe versus Ball & Gate valve
Second, you can buy globe style control valves that are built to class umpty-umph drip tight leakage rates in the dribbles per hour/year/lifetime range, but they always have SOME leakage rate associated with them. As BigInch has so succinctly noted, at some point in its life, the valve seat will get cut, will wear down from its original tolerances, or will just get some trash wedged in it and it won't shut off. Use devices whose only function is to shut off and that are good at it when called on to do so.
rmw