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Join Date: Jul 2010
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Wireless Control (Globe) Valves 2-8 Mile Radius 100% Oxygen

07/26/2010 2:09 PM

I am currently doing research on how to remotely control several globe valves from a 2-8 mile distance. The basic requirements are that the system is intrinsically safe/explosion proof and must fit 1/4 inch to 1/2 inch diameter lines. The globe valves are inside a surveillance room and they are used to meter 100% oxygen to be used in outer space. The process needs a highly accurate actuator and smooth motion with small increments for increased metering precision. In case of an emergency such as a gas leak I would like the valves to be closed very quickly. So any suggested RPM rating for 1/4 inch and 1/2 inch diameter valves would be helpful. Even better would be an actuator whose speed was variable.

One idea I had was to do this using radio frequency technologies such as pulse width modulated signals and a servo motor used in RF toys or possibly the Pakscan P3 Wireless by Rotork. I am open to other wireless technologies such as infrared as well as different manufacturers. However, keep in mind that the valves will be controlled from control rooms 2-8 miles away so RF will most likely be more appropriate but IR can be used inside the room where the valves are actually located.

I would also love if the temperature of the actuator system, actuator and/or valve position could be read and sent back to the control room. Low power consumption is ideal as oxygen enriched environments such as this are very dangerous when it comes to heat, sparking, and particle collisions.

I am a computer engineering student so feel free to be as detailed as possible with your valve suggestions as my grasp of the mechanical aspects are not that strong

Any information regarding wireless controlled valves will be greatly appreciated:

Manufacturers, existing wireless control valve systems, general suggestions, anything related.

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#1

Re: Wireless Control (Globe) Valves 2-8 mile radius 100% oxygen

07/26/2010 3:29 PM

Would fiber optic communication be possible?

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#2
In reply to #1

Re: Wireless Control (Globe) Valves 2-8 mile radius 100% oxygen

07/26/2010 4:54 PM

Yes, I could use fiber optics but I would have to do more research on the subject. I didn't think of fiber optics because it is traditionally a wired technology. However, fiber optics and Radio Frequency can be combined to create the wireless control that I'm looking for. I just wanted to keep it simple and the costs down but I'll definitely look into fiber optics. Very good suggestion. Thank you.

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#3
In reply to #2

Re: Wireless Control (Globe) Valves 2-8 mile radius 100% oxygen

07/26/2010 5:10 PM

Indeed the fiber optics could be used to transfer data/commands from the hazardous area to a point where an RF link would be safe.

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#4

Re: Wireless Control (Globe) Valves 2-8 Mile Radius 100% Oxygen

07/26/2010 8:40 PM

1) Your term "low power" needs to be defined for both valve control and wireless. What do you mean by 'low power'?

2) Piping or tubing exposed to oxygen has to be oxygen cleaned to remove any trace of oil.

3) Lubrication of the valve packing around the stem needs to be taken into consideration in light of #1. One of the teflons will probably provide sealing without excessive friction in the absence of lubrication.

4) Small line size valves are the domain of firms like Research Control, who's been a player for years
http://www.badgermeter.com/Industrial/Valve-Products/Research-Control-Valve.aspx

5) Actuator: It isn't at all clear how you intend to power the actuator. Is instrument air available? Air is inherently intrinsically safe.
Electric actuator? An electric I/S actuator is likely to be harder to come by than an EXP. I just haven't seen one.

Air operated actuators tend to be very fast responding, with the controller and settings on the positioner used to determine the final response.

6) Warning: Using unlicensed, open frequency wireless for ANY control situation is a situation requiring some serious !! risk assessment. It would be foolish to even look at anything associated with RF toys, unless this is paper project only. There are industrial wireless vendors whose offerings take into account the risks associated with wireless control.

Most valve vendors, if they offer something wireless are private labeling wireless. If a valve company does not offer wireless, it's no big deal, because wireless is dealing with the control signal and probably some feedback position switches, not the valve/actuator/positioner itself.

7) Low flow gas flow meters with a controller and control valve are frequently integrated into one package, using thermal dispersion for a mass flow measurement and an integrated control valve/controller. Brooks is an example of such, but there are a half dozen others with the same packaging.

http://www.brooksinstrument.com/flowmeter-flowcontroller-products/coriolis-thermal-mass-flow/thermal-digital-elastomer-sealed-gas.html

I never used one of these in a hazardous area, so I don't know what hazardous ratings are available.

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#5
In reply to #4

Re: Wireless Control (Globe) Valves 2-8 Mile Radius 100% Oxygen

07/26/2010 10:48 PM

The network/control system is my main concern. I was thinking I could just remove the handle and/or old actuator from the stem and just pop on a wirelessly controlled actuator but I don't have experience with control valves hence I joined this forum. Many Thanks for the response Carl_E.

1) What I mean by low power is just the standard Power = voltage*current. Preferably I would like the lowest possible current drawn by both the wireless system and it's components and the actuator. I did not mean low power as in low torque or anything related to low rpm or the like.

2) The valve stems are mounted on a wall and not exposed to the oxygen. I read about the cleaning procedures in the ASTM mnl 36 oxygen manual but I don't have to worry about that because the company will take care of any maintenance and prep work.

3) I didn't take lubrication into consideration but I think the company will take care of that as well but I will also research some lubrication options just in case. Anything that reduces sparking and can survive high temperatures in case of a fire is a plus.

4) Well I would like to add that I'm not replacing any valves just modifying some existing valves that already have a pneumatic-solenoid actuator.

5) How am I going to power the actuators? Very good question. Right now I'm stuck on batteries even though I've found some alternative solutions such as a new power source that uses ambient vibration and piezo-electronics to provide power but I don't think it would be sufficient to power the actuator.

I agree 100% that air is the best choice as far as intrinsic safety is concerned but I was told that the company I'm doing research for is trying to get away from the pneumatic system. But I will reconfirm this because it would make my job a lot easier if I can still use air.

6) Well I was planning on using either a servo or stepper motor and of course I would use the unlicensed 2.4Ghz frequency if I was forced to but I think the company already has licenses for other frequencies. They also own satellites that I was hoping I could use but this was just my initial idea. An impractical idea I'll admit. However, I'm now researching and leaning towards an optical wireless/fiber-less optic network. I know the disadvantages of line-of-sight systems like these but the pros outweigh the cons thus far.

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Carl_E (1); CompEng-JM (2); Unredundant (2)

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