Measurement flow

[valdis]

I'm slightly confused.
We've encounted rather a complicated situation incuding the following items:

1. As everybody knows, the existing measuring methods applying restrictions are not always acceptable. When we talk about large amount of mechanical and other admixtures, impulse lines are very often plugged, besides the medium contains H2S which is a very dangerous factor for servicing personnel.

It seems that all the factors do not allow us to choose anything else but Vortex and Ultrasonic flow meters as well as other up-to-date methods.

2. Legislation of the country where we work requires an obligatory annual inspection of all measuring instruments. On the other hand, company's management won't even consider the issue of annual process line shutdowns operating on a twenty-four hour basis only for their calibration (say the same Vortex or Ultrasonic cannot be calibrated other than removing it and installing in the line with a flow meter which accuracy rating is higher).

Do you have any ideas how we could solve this issue?

 

[hacksaw]

Build your plant in another country...

that said there is a great deal of interpretation of the word "inspection"

in the case of a vortex meer, it could simply be a loop check rather than a flow test. sounds like you need a bit of creative interpretation of what is needed.

In any event you can consult the operating manual of the meter, or call the supplier, to document what constitues an inspection.

critical meters (or transmitters in some cases) can always be installed on a redundant basis, so that testing can be performed without taking a shut down.

 

[sjstn]

In critical cases we can have redundant meter in line. In non-critical cases we can have by-pass line to isolate the meter.

Normally manufactures will not suggest for calibration of Vortex flow meter frequently.

The max thing is, we can calibrate the Remote converter section.
Unless until we are having a Flow Calibration Lab we can not calibrate the sensor section.(bench calibration)

Hope I am right.
Expecting other views

Thanks sjstn

 

[StormPt]

Obviuosly sjstn is right. Every equipment working 24/24 must have a redundant brother or a by-pass.

 

[Sierra]

Consider a Insertion Vortex with a Hot=tap system. See

http://www.sierrainstruments.com/products/240_241.html

(Model 241 with Hot-tap)

 

[jmw]

Try consuling companies such as SGS or any other company that provides on line proving. Possibly you can design your installation with proving stubs (take offs for temporary connection to a mobile prover). Then you need a company that can bring in a mobile meter prover. Size amy be all important. I would guess there are others who can advise you of suitable companies. I just know of SGS (moor Barret and Redwood?)

 

[shobi]

There are few options available. One old fashion way is to use a by-pass around the meter, so you can service/inspect your meter without interrupting the process. The other option is to buy an integral coupling (from rosemount). Rosemount also has a newer model 3051S which enables you direct mounting. Check with your local rep.

 

[sunflake]

Have you looked at the wedge meter? I have used them on slurry, asphalt and bunker C. Very durable and easy to verify calibration. The ones I use are the old Taylor units, now sold by ABB

 

[jmw]

The wedge meter featured in another thread somewhere. As i recall the problem will be its limited accuracy. If anyone has actual performance data it would be nice to know how it performs over a range of flowrates, densities and viscosities. I suspect that as a dP device, its performance will vary.

 

[southampton]

I have used portable strap-on ultrasonic meters to calibrate other ultrasonics and mag-flow meters by clamping on to the process pipe and comparing measurements. This can be done without any process disruption if you plan carefully.

The only problem with this is getting vrification of the clamp-on meter's accuraccy with the process fluid, which is usually done as part of the commissioning activities.

 

[IRstuff]

If you design your plant to accommodate such a procedure, it should be no big deal.

If, on the other hand, you design your plant ignoring such a requirement, then you will have problems.

TTFN