Mass Flow Controls

Good day all. I would like to know if anyone here could give some advice for mass flow controls for HF Gas? The distributor is telling me 3-4 weeks delivery and I can't go that long. I need them for HF Gas that will interface with a PLC-5/40, using a 0-5 volt signal. It currently has a Parker Series 200 mass flow control. I will need 4 of them, 2 immediately. Thank you much.

The PLC can serve as the controller but it's going to have to have the flow from some kind of a meter and a valve to control. Do you have these?

The PLC is going to have to have an analog input card and a output card, do you have these?

Mickey said:

The PLC can serve as the controller but it's going to have to have the flow from some kind of a meter and a valve to control. Do you have these?

The PLC is going to have to have an analog input card and a output card, do you have these?

Click to expand...

Currently I have the Parker flow controllers but they use the signal from an analog output card (1771-NOVA)and then sends the signal to the analog input card (1771-IFE), all of which are in place, using 0-5 Volt signals. I could change to mA if need be.

Have you checked Endress and Hauser, or Micromotion flowmeters? I don't know what HF Gas is. So instrumentation just another sensor to me.
One shop I worked at had all kinds if instrumentation. I usually don't get hung up on the brand name.

I think he needs actual analog flow control valves with possibly a flow rate feedback?

+1 for Endress for highly accurate Magnetic Flowmeters. They are rock solid in our worst (wastewater) environment.

I have never used an analog or servo flowcontrol valve for a fluid control, and I am certain that HF gas has highly specialized requirements.

We do have some positionable motorized valves with end switch for feedback, but we only use them for on off control.

Give us a link to the valve/meters...

JeffKiper said:

Have you checked Endress and Hauser, or Micromotion flowmeters? I don't know what HF Gas is. So instrumentation just another sensor to me.
One shop I worked at had all kinds if instrumentation. I usually don't get hung up on the brand name.

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Me neither Jeff. I don't care what the brand name, as long as it works. I do know that the HF Gas presents a bit of a challenge for the control. I don't know if it is the gas itself or the fact that it has to hold a pretty close tolerance.

OkiePC said:

I think he needs actual analog flow control valves with possibly a flow rate feedback?

+1 for Endress for highly accurate Magnetic Flowmeters. They are rock solid in our worst (wastewater) environment.

I have never used an analog or servo flowcontrol valve for a fluid control, and I am certain that HF gas has highly specialized requirements.

We do have some positionable motorized valves with end switch for feedback, but we only use them for on off control.

Give us a link to the valve/meters...

Click to expand...

Nice avatar!You are correct. This does require analog control, so I can not use a digital device (simple open/close). It is tightly regulated.I can find nothing online for the Porter/Parker Valve that is on it. That has been a huge part of my headache.

Something like this? http://www.aalborg.com/index.php/main_page/product_overview/id_product_overview/24?gclid=CIK-mL6Sn7MCFUWo4AodRjUAcA.
That unit has a built in flow control valve. You need to find out the flow volumes, temperatures, pressures. IMO due to the nature of HF gas, no vendor is going to have any of these things on the shelf. It still will need to be calibrated with the gas you are going to use in your process.

ceilingwalker,

HF is nasty stuff.
Not just any valve will do! please do your research on this stuff. putting the wrong material used in the construction of the valve with the HF can be disasterous.

the chemical properties of HF dictate what materials the sensors can be made of, how the instrumentation is constructed, and what the wiring requirements are.

regards,
james

I can find nothing online for the Porter/Parker Valve that is on it. That has been a huge part of my headache.

Click to expand...

http://www.parker.com/literature/Porter Instrument Division/MFM & MFC (D-Conn.) (FM-898 Rev. E).pdf

Break this problem down into it's constituent parts.

The flow control part of your system is not a particular challenge. Whether the analog signal is 4-20 mA or 0-5 VDC or whatever doesn't matter. You need to read the flow, implement the control logic to conrrect the error, and output to a valve that follows your signal by changing its position.

If HF is Hydrogen Flouride you have significant issues with corrosion. I believe that stuff will etch glass. You need to find a control valve and a flow meter that will resist the HF. Start with the material that your piping system is made from. If your HF is gaseous then I don't think a magmeter will work for you. Find a local distributor or manufacturer's rep that will work with you. Since you are in Phoenix I suspect there are a lot of distributors around used to working with nasty stuff in chip foundries etc. Try to locate one of them.

James Mcquade said:

ceilingwalker,

HF is nasty stuff.
Not just any valve will do! please do your research on this stuff. putting the wrong material used in the construction of the valve with the HF can be disasterous.

the chemical properties of HF dictate what materials the sensors can be made of, how the instrumentation is constructed, and what the wiring requirements are.

regards,
james

Click to expand...

I have had only a small amount escape the reactor a couple of times. Smallest tracable amounts evacuates the plant. I appreciate the warning and am aware of the dangers. That's why I put that it must be for HF Gas.

What about an ultrasonic flowmeter? No need to even open the pipe with one of these.

ceilingwalker,

i did not mean to imply that you didn't know your stuff.
many times i have done work at plants in which someone jumped the gun and stuck a valve on and didn't do his homework.

i did a project with sulfuric acid and i did my homework, i researched the materials and even specified on the materials list what to use. our mechanical designer changed the order so we could save $5k. system worked great for 10 days. that's how long it took for the acid to eat through the containers he ordered. the boss was pi@#$#@ and tried to take it out on me.
i showed him my drawings and specs and he was really mad because we had sat down and went through the design and chemical analysis and he agreed with my specs and approved the order.


i read your posting as if you were in desperate need of an immediate fix and your profile does not tell your background.
i apologize for any misunderstanding.

regards,
james

James, I know ceilingwalker well ... I can assure you that he took no offense with your well-intentioned comment ... he is simply not that type of person ... I can see how you might have misinterpreted the tone of his response – but I'm certain that he was just politely confirming that he had indeed considered the perfectly valid points that you had raised ...

there is one other point that I would like to bring up ...

the subject (as I understand it) is the need for a MASS flow meter/control device ... specifically, I think that ceilingwalker is in need of a device that will consider not only the VOLUME of a gas stream – but also the DENSITY of the gas flowing through his system ...

my understanding is that a MASS flow sensor works on a different principle than some of the other solutions which have been brought up for discussion ... specifically, a MASS flow sensor considers not only the volume but also the density ...

I might be wrong – but I think this point needs to be considered – and possibly discussed ...

here's some light reading material on the subject ...

http://www.omega.com/toc_asp/frameset.html?book=Green&file=MASS_FLOW_REF

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