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I have saturated air (with water) flowing in a large duct at a nominal 1 ft/sec velocity. There is a sudden contraction such that the velocity becomes 45 ft/sec in the duct and the flow continues on inside the smaller duct for a long distance (not a nozzle). I am wondering how I calculate what...

Thanks for your helpful response guys. An EI&C friend recently told me to stick with HART as well. We did put three Micromotion coriolis on Modbus in the last plant but I think we will hold the line and see how it goes. Appreciate the input. Bob

You can also use the symbol for a magmeter and instead of putting an "M" in the box, put a "C". Then update your P&ID lead sheet in case someone doesn't understand.

What I mean is...why so many architectures and "open" standards. I didn't even mention DeviceNet or others that I am not even aware of. Perhaps Debunk is a harsh word. But I am really trying to understand which ones merit investigation and which ones are just "piling on".

Can anyone point me to a good reference that describes and debunks the various architectures currently in use for control systems. In particular, I am interesting in learning more about the following: 1. Analog (4-20ma) and Discrete IO versus 2. ModBus TCP/IP versus 3. Profibus, versus 4...

Folks, Our corrosion expert has inspected the tank. A piece is being removed for testing. His first thought is carbide depletion SCC and, as stanweld suggested, many of the cracks appear to have originated from OUTSIDE the tank. On removal of the insulation (simply 2" of fiberglass with...

stanweld and EdStainless, Interesting points about potential for external origination. That is very possible since the original leak ran down the sides of the tank and dried salt can be seen in many areas. We are proceeding with expert analysis. I will keep the group posted. In my research, I...

hacksaw and metengr: Thank you both for your insight and reference. The solution treated varies but generally consists of extremely high (saturated) levels of sodium sulfate and some sodium chloride, although generally the chlorides are below 100 mg/L. The vessel is 316 and NOT 316L as I...

Hello, I am a chemical engineer with no materials science expertise. I have a problem with a 10,000 gallon 316 Stainless steel reactor. It is 10' diameter with ASME heads top and bottom. This may sound strange but the vessel normally runs with only 12 inches of liquid (sidewall depth). I sparge...

To determine if an aqueous phase inorganic precipitation reaction will proceed, look at the solubility of the reagents vs. the products (as a rule). In this example, you have sodium sulfate that is very soluble and lime (very, very insoluble)...can't recall the solubility off the top of my head...

Don't leave out transit time in your evaluation.

bpeirson, As mentioned, Access will easily import your data into a database that has tables representing proper normalization of the system data. You may need to pick up a good book on Access to appreciate this, but in the process of pulling your data into Access, it is best to pull in the...

cornejoi, Your response was very helpful. I would like to see the use of Interlock numbers you reference in your reply. I have not seen such a thing on P&IDs before. If possible to send a P&ID illustrating this concept? I would be very grateful. Bob Cook

MVD, That is very good work. Well done!

A possible solution is to bleach the color out. Run some trials with sodium hypochlorite. If possible, use at pH 5-7 (slightly acidic). You don't seem to understand the nature of your water, hence the general reply. Good luck.

11echo, In the next generation (the one after yours), process engineers and computer jockeys must be the author and creator to maintain an edge. Your analogy harkens back to the days when we scribbled our memos and report on paper and gave them to a secretary to type up. Your options are few...

A nuclear device will work but is not cheap. I like saxon's radar suggestion. Suggest you check out and/or call Ohmart-Vega.

Thank you all for your input. I actually found the device I was in need of some time ago. It can be found here: http://www.flygt.com.pl/products/lift/LIFT.HTM

It sounds like you have way too much gain. Try reducing it 20% at a time. As you do that, time the peak-to-peak overshoot and set your integral to three times that amount. Leave derivative at zero. The other responses are also very good. I am trying to give you the basics to make what you have...

I agree with the previous response. VFD's are commonplace on the smaller motors. If you are talking positive displacement, they are really a good option. If you are talking centrifugal pumps, its really easier just to throttle flow with perhaps a spillback. For big stuff, that is the way it is...