Do we need a-lot of pressure gauges & flow meters, for our new piping system? 2

[amata42]

Hello Members,

I am a new mechanical engineer here at this company. And we are designing a piping system for our facility. We are growing biological matter (plant cells, micro-organisms) in indoor water tanks. And we are doing the pipes, valves, sensors... water, air, & carbon dioxide. And, I am the only mechanical engineer (AND I'm entry level)... so I've never design and built a piping system.

The question came up: Should we get a-lot of pressure gauges & flow meters? so we can put all through-out the system... check pressure at different spots, check flow at different spots...

I believe the answer is: YES! YES, YES YES!!!

We have never done a piping system before. And frankly, I'm not really sure how the system is going to flow... Did I do calculations? Yes, of course. I did many calculations by hand and using

http://www.pipeflowcalculations.com

... BUT... we do NOT have pipe system design software (like PipeFlow Expert, etc). And flow & pressure gets a little complicated when you get networks & parallel flow, etc.

I'm trying to convince my boss to buy many pressure gauges & flow meters... but he doesn't want to buy many. He only wants to buy a few. It's because we're a start-up... small company. But I disagree. I think we should buy many. We don't have a-lot of money but we have some... (we have investors that have put in "some" money).

Let's put it this way...: we are NOT "super-tight"

I have a good idea of how the system is going to flow, but I'm not sure, and this is my first time doing this. I think we're going to run hoses for our first 6 - 12 tanks. I just want to get some feedback from some Engineers who have been doing Pipelines, Piping, and Fluid Mechanics Engineering for a long time -- so I can confirm my "conclusion" that: we DO need to get many pressure gauges & flow meters. AND it's worth the money---

Thank you

 

[zdas04]

Hire an independent Engineering company to review your design. I do these reviews all the time and it usually costs less than $10k. If you hire a major it'll cost a couple of hundred thousand dollars and probably can't be justified. Getting someone like me to look over your specs and drawings can be very cost effective.

Every set of threads in your plant will be a potential leak point. For a gauge that tells you something you want to know, the risk is justified. For a gauge that is redundant it isn't. The problem is knowing the difference.

Flow meters are a bigger deal. All "biological matter" that I'm familiar with is VERY sensitive to shear forces. Several meter technologies impart significant shear and would be more damaging to your fluids than they could ever be worth. Again, if the data is going to actually improve the process then the risks are possibly justified, if it is redundant then not so much.

We all started somewhere. Luckily most of us started where we were not the only ME in the plant. You have what you have, but trying to learn piping (e.g., did you know that the high-viscosity correlations in most commercial pipe simulators don't work?) while building a plant is asking too much.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[HowDidYouBreakThat]

I understand where you're coming from. I like having an abundance of information so I can accurately assess how a system is operating. From your bosses perspective, be able to clearly explain to him what difference having/not having a gauge/flow meter at a particular location will mean to the operation.

Terry

 

[pmover]

A suggestion . . .

analyze the piping system &/or the plant and locate critical locations that are essential for determining performance of the plant or equipment. For example, pressure gauges at pump inlets and outlets are good locations to determine pump performance along with inlet temperatures. Heat exchangers, inlet and outlet pressure and temperatures. do not worry so much about placing gauges along piping just to determine pressure loss. that can be done analytically and by observing gauges at rotating machinery inlet/outlet connections.

look at the cost of each gauge and each flow meters. can you economically justify them at each location? what benefit is there to place the gauge/meter at that location? by not having a gauge/meter, what essential operating data will not be known and how will it impact the plant operation. how critical is the parameter to be obtained?

some ideas to think about. Oh, remember that gauges and flowmeters have a degree of accuracy as well. it would benefit you to be knowledgeable of this fact.

however, your boss has final say. show the boss the economics and benefits or by not having the data, what are the shortfalls.

good luck and enjoy yourself.
-pmover

 

[MikeHalloran]

You could justify a fair number of flow meters (assuming they didn't kill your bugs of course) if you were designing a continuous flow process.

Given that you will be pumping bug soup from one tank to another and then letting it sit and brew for a while, flow meters might be less important, since you can calculate flow rates from fill and drain times. ... which you can get from sight glasses or floats or other sorts of level transducers, another decision you'll face.

Given that your pipes will be full of growing bugs, there might be some concern that they will foul or eat pressure gages, so you would probably want isolation valves to make gage replacement easy. If you use pressure transducers that you want online all the time, you might want some means to isolate and flush them remotely; that's just a conjecture; I know nothing of your bugs.

I agree with David that you should be able to justify getting some experienced help for your project. It will be money well spent.


Mike Halloran
Pembroke Pines, FL, USA

 

[europipe]

Like David said; hire a pro who does the PID's and linelist,
from there he'll guide the way.

 

[BigInch]

No sense putting them where you don't need them.
Locate them at strategic locations where they will give you the diagnostic information that you need.
Any more than that will be potential headaches, which in a bio system could be substantial due to plugging by biomatter, or in regards to maintaining sanitary conditions in all nooks and crevices.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[MikeHalloran]

You need the pro to tell you where you don't need the gages.


Mike Halloran
Pembroke Pines, FL, USA

 

[amata42]

Thank you all for your replies. I think that's a good idea to hear an independent contractor for this, but I don't think my boss (who is the president/CEO) has the budget for that... we are a start-up. But I will mention it to him...

in the meantime,... I will determine critical locations to place the gauges/flow-meters ...