Butterfly Valve in Natural Gas Line

Do you wish to use the actuator or actuated butterfly valve ?

If you wich to use the actuator, of course you have to hook it onto another valve, and then the compatibilities are to be checked (most likely will not suit since butterfly valves will be a half turn valves and other valves will not be or will be plunger type-gate galves etc- depending on its type)

If it is pneumatically actuated butterfly - then as far as my knowledge goes, it can not be used to control (regulate) the gas line. Butetrflies are on-off valves and are not control valves.

However for on-off valve application, i don't see why you can not use the pneumatically controlled butterfly - API permits the valves as well as actated valves

pneumatic actuator of butterfly valve to control a natural gas line? No for it will not give tight shut-off and will leak, but you can use pneumatic actuated ball valve to control a natural gas line?

but you can use pneumatic actuated ball valve to control a natural gas line?

Here I mean in your case only to give a tight shut off not possible with a butterfly valve.

To modulate the gas you need a butterfly valve preceded with an on/off valve. Please read my reply down the threads.

"If it is pneumatically actuated butterfly - then as far as my knowledge goes, it can not be used to control (regulate) the gas line. Butterflies are on-off valves and are not control valves."

Not exactly true. Butterfly valves are used extensively at my company to control gas and air for large industrial furnaces. Most are motor controlled, but their are still several pneumatic actuators in use.

Check these out:

http://www.namfg.com/c-index/c-lit/valves/1123-26_bul.pdf

The North American web-site contains extensive information on control valves, and more:

http://www.namfg.com/c-index/valves-index.htm

Not exactly true. Butterfly valves are used extensively at my company to control gas and air for large industrial furnaces. Most are motor controlled, but their are still several pneumatic actuators in use.

You are 100% correct. To Modulate gas flow with the Proprotioning pressuretrol of a Boiler/ temperture control of a Furnace you MUST have to use Butterfly Valves operated, mostly with a Modmotor or pneumatic actuator with pneumatic/ electro-pneumatic positioner. This must be preceded with a on/off Solenoid Main Valve/ Motorized slow-opening-quick closing Actuator Valve for shut off & on of gas.

Yup, and before the butterfly, you should have 2 of these:

http://www.maxoncorp.com/Directory/product/Gas-Electro-Mechanical-Valves/438/ShutOffValvesMechanical

Before and between them a couple of these:

Brick,

I guess if we are going to recommend Maxon I would recommend there Micro Ratio valve for "control"of natural gas.

2 depending on the rules of the gas people of the country. 2 where double-block and bleed system is a must. That means 3 - a 1" solenoid valve Normally open installed in between your 2 valves to vent when both your valves are Normally closed and vice-versa.

1 depending where the country's rules are not that strict.

Yes. The "control" of natural gas with butterfly valves driven by linkages, electric or pneumatic actuators is the most common way to limit the flow and quantity of natural gas to large boilers.

Obviously there will need to be other safety shutoff valves before the control valve to meet local code and common sense.

Yes. The "control" of natural gas with butterfly valves driven by linkages, electric or pneumatic actuators. 99.99% of the Packaged Boilers I've seen are with electric modulating motor of Honeywell/ITT. I've yet to see one with a pneumatic positioner on the burner gas modulation.

Good morning, miketheboilerguy. Since I would like to know a little about boiler systems, I ask the following. I presume the use of the butterfly is desirable because its action is swift, but since it may leak slightly, a more positive shutoff valve is placed upstream which is actuated after the butterfly valve is shut off. Is this correct?

This prompts the next question. If the above is correct, and a positive-sealing ball valve is used upstream, why not simply use the ball valve in place if the butterfly, assuming they both can be operated swiftely, due to their 90º angle of operation? Thx.

Pneumatic actuators are not used much today. I prefer the Honeywell Herculine series:

http://hpsweb.honeywell.com/Cultures/en-US/Products/Instrumentation/ActuatorsHercuLine/Herculine2000Series/default.htm

4 to 20 milliamp, or relay output, and completely programmable. Very versatile.

http://hpsweb.honeywell.com/Cultures/en-US/Products/Instrumentation/ActuatorsHercuLine/Herculine2000Series/Features/default.htm

Also, we had to install these, required for an entry permit:

http://www.schuf.de/products/line-blind-valves

And don't forget hi and low pressure switches:

and a regulator:

http://www.namfg.com/c-index/regs-index.htm

Don't forget a gas line strainer.

Mike,

I am curious what mesh strainer you use/recommend? Mostly around Chicago I have seen full size dirt legs.

Second question is how often are the strainers serviced for debris or oils?

Thanks!

A wise guy would say "Sure, you can do anything, if you have enough time and money!" It is possible, but not always advisable.

First question, is this a combustion or other application?

Who is your insurance company and what do they recommend and/or require for safety equipment for the application? A few of them will provide decent technical advise on requirements. (After all, if you burn down or blow up something it might cost them a lot of money!)

Buy, beg, borrow or steal a copy of NFPA 54. Casually check with fire dept. whether they have any requirements in addition to NFPA. (After all, they are normally the first to try to stop, put out, and/or clean up from your explosion or fire.)

You have some excellent advise from good people here. Thank each one and take time to learn why they are giving all of this advise.

Is it possible to use a pneumatic actuator of butterfly valve to control a natural gas line?

If it is a natural gas pipeline that requires pigging you can't use a butterfly valve. You can only use full bore Ball Valves.

Well, once again the OP has not given us enough to go on. So, we really don't know, from the limited information that the OP gave, what he's really trying to do here.

If he is dealing with a combustion application here, the above information is not only correct, but required for a safe instillation.

If the OP is talking about gas transmission over a distance, I have no knowledge of that.

Correct equipment= application.

There are very few of us in this forum that deal with industrial heating applications. It's one of the few topics that I actually know a little something about. So cut me a little slack for going overboard and having some fun.

So, to this OP, and to the many, many others, provide information about what you are actually trying to do. We're not mind readers. If the information is important to you, then state your situation and goals. Don't waist my time and I won't waist yours.

If the language is a problem, just say so. Tell us where you are from, it could effect the answers.

If it's homework, say so. We won't give you the answer directly, but will aim you in the right direction, so you can learn.

I think it's called "meeting us half way".

There's nothing wrong with using actuated butterfly valve for control of gas flow (or liquid flow for that matter). Suppliers publish Kv data to enable proper selection for the ranges of flow and ΔP required.

Several posters have mentioned lack of tight shutoff and assumed you're feeding a boiler, but you haven't said this, and need for tight shutoff and other features depend on details of what you're trying to do.

BTW, according to elastomer resistance data I have, EPDM is no good on methane (though very popular for butterfly valve liners.

Cheers.........Codey