Steam Meter Suggestions

[Barmmer]

I operate the utility system on a large campus and in an effort to get the energy use under better control I am planning on replacing the current steam sub-meters with newer ones with some better communication options. The current ones (shedders) are pushing 15 years old and have some turndown issues. Some areas see a turn down as high as 30 to 1. I am wonder what success has other people had with what types of meters. Also has anyone used the wetted ultrasonic meters?

Just FYI
the steam is to meter 120 PSIg saturated.

 

[ilan7]

For saturated steam we are using the Rosemount Mass Probar which includs temp. compensation and gives us good reading in Kg/hr steam flow.
I also have prices for ultrasonic meters for steam but haven't had the chance to use it (yet).
Stop at:

http://www.rosemount.com/products/flow/mprobar.htm

 

[hacksaw]

the older shedders were limited to a 3 or 4:1 turndown and limited selection of meter sizes. this is not a problem with the newer models.

the averaging pitots (mass probar's etc.) are fine, but you have to pay close attention to all of your installation details, that thats good advice for any flow meter come to think of it...

 

[MRGJR]

As far as communication, you may want to check out Honeywell's new XYR 5000 Wireless Transmitters. Some limitations depending on locations, but good for transmitting data from various locations like a campus environment. Their standard Smart Tranmitters have the std 4-20, DE, Hart, Foundation Fieldbus etc. Check out Chemical Engineering article Dec 03. Has info on wireless in general as well. Or link to

http://content.honeywell.com/imc/fi/wirelessTransmitters/

Good Luck

 

[Barmmer]

Thak you for the information. I think I'm going to try an ultrasonic from Panametrics. I use their ultrasonic energy meters on my water systems and I'm very pleased with them. They claim a very high turndown ~150:1 but a maximum velocity of 150 ft/s which I need to consider.

MRGJR I have tried wireless this and that but the granite and marble that make up most of my buildings limits them. I have been using ModBus on most of my meters.

 

[quark]

Steam measurement using ultrasonic meters is new to me and never knew it before. As far as other metering devices are concerned, I would go with vortex meters for their accuracy, turndown ratios and rugged construction. Averaging pitot tubes are a bad option with varying loads and their accuracy even with 3065(multivariable) transmitters is doubtful at 1%.

Endress+Hauser vortex meters come with tuning fork type mechanism which directly gets connected to the shedder bar unlike the strain gauges used in other makes. This will help you getting accurate results even when the pipe vibrates. Other mechanisms require separate filters to nullify the pipe vibrations.

Have you thought of HART?

Regards,

 

[hacksaw]

the ultrasonics are best if you can afford them and your temperature issues can be worked out(they can).

what is the cost per measurement that you have to work with?

 

[Barmmer]

quark, I have tried HART but find it is not nearly as reliable or robust as a dedicated communication. plus it sometimes interferes with my VFD even though the shields are terminated correctly

hacksaw, what temperature issues are you refering to? I would like to know all the drawbacks to every technoogy. I don't have a cost per measurement number to work with as these really aren't for cost recovery they are mostly to manage an 8 figure steam annual cost.

 

[hacksaw]

the temperature rating is dictated by the design specifics of your particular vendor. i am referring to the fluid temperature. as long as you are dealing with saturated steam most vendors don't have a problem but you have to ask.

at $5/lb sounds it appears that you like 50000 lb/hr system (25000 kg/hr) or so, depending on the amount of make up you have and your fuel cost.

what level of superheat are you running?

 

[Barmmer]

I would love to have $5/lb steam..i'm somewhere between 12 and 17..depending on season and fuel. this is a contacted fixed cost. so justifiing a better meter is a little easier
but I want to make sure I get one that meets all my needs. depending where in the system and the load it can run with a 3-4 degree superheat to saturated. I will have to inquire about performance with these conditions

 

[hacksaw]

just use vortex shedders, they are easy to use, tolerate a lot of variations in the service conditions, and cost effective.

 

[jmw]

If your steam quality is variable i.e. temperature and presure can change, consider that whatever meter you select you should also consider a steam flow computer with steam table look up or similar.

JMW

http://www.viscoanalyser.com

Eng-Tips: Pro bono publico, by engineers, for engineers.

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[WAT71]

I have been working on steam for a short time and any one can correct me if I am wrong but the steam doe not have enough mass or solid particals for ultrasonic or doppler to ping off corectly. I have a military base that would love ultrasonic but the error rate is bad. has any one installed a inline and ultrasonic together I am working in a system with 4,785,496 btu per hour 3 Gibralter fire tube boilers 143 HP
Thanks
Alex

 

[alexpln]

... you can run installation cost and see what would be worth putting in - DP meter or ultrasonic
... you can download the calc prog from here

http://www.lavell.lnk.pl/str/soft/soft.html

 

[hacksaw]

WAT71, good question, but you need to start a new query to avoid tangled responses