Changing line size with flowmeter

[lapsd]

Hi Everyone,

I have to change a discharge line pump from 3" to 4". This line has a flowmeter. What are flowmeter's parts that I should change?

It's a magnetic flowmeter. However the Operating personnel does not trust it. Is there another flowmeter type we have in the market, which is better?

Thanks,

 

[CARF]

Dear lapsd,

If this new pump has the same capacity as the former pump, then you do not have to change anything. (Supposed the flowrate is already within the measuring range of the flow meter.) Many magflometer have smaller diamter than the pipe.

Why they do not trust it? Log the flowmeter signals with a DATALOGGER to test reliability.

Regards,
C.

 

[jsummerfield]

Many flow meter technologies could replace the magnetic meter. You could rent a clamp-on ultra-sonic meter to check the flow. Two ultra-sonic meters have mutually exclusive requirements. The transit-time requires the fluid to be free of bubbles. This may apply to solids. The doppler requires bubbles, or perhaps solids. A non-invasive clamp-on meter could be worth a try for the good test. If you google for manufacturers, the transit-time is also called time of flight.

John

 

[CMfgE1]

Mag meters work off of conductivity of the fluid that runs through them. There are electrodes that are positioned in the walls of the flowtube that just touch the process. The more conductive the material (say water) the better or stronger (in turn more accurate) your meter will be. As long as the range of the meter is set up to handle the larger dia (i.e. gallons per minute)then you should be all set. You might have to purchase a new flow tube for the larger diameter if its not desirable to reduce the pipe to mate the existing flowtube. You can reduce the pipe without effecting the mag meter. You didnt mention the manufacturer.
Also flowtubes are usually matched to the meter. Once you post the manufacturer I can give you more info.


Good luck

 

[hacksaw]

if the existing meter is not working, and if the pump was undersized, then what sort of engineering analysis was done for the design and is the meter even suited to the service?

just a concern...

 

[zdas04]

I don't know about Lapsd's operation, but the operations I look at "don't need no stinkin' engineer to do measurement". When I show them a combination of decreased uncertainties along with capital savings from doing the engineering, most still don't get it.

At the International School of Hydrocarbon Measurement (ISHM, a really good conference held in Oklahoma City in May every year) the vast majority of engineers are vendors - it is a rare company that sends (or even has) a "measurement engineer".

For example, when I ask meter-tube fabricators for their sizing calculations I either get a truly blank stare or a copy of API 14.3 Part 2. Neither of which bodes well for any sort of measurement in Oil & Gas.

I've heard a lot of complaints about mag meters in intermittent service (i.e., on a line downstream of a dump valve). The operators frequenly have to take them out of service and "clean the optics" (I've never done it and don't know what is involved) which the operators really hate.

David

 

[jmw]

Some magmeters are prone to coating of the electrodes, some come with ultrasonic self cleaning cycles or alternatives and others are less prone.
Like everything else, there is more than one style of magmeter, DC Pulsed, AC etc.
But hey, who needs an engineer? You just call in the suppliers salesman and, rather than spend money on engineering or on commissioning, for example, you just get the salesman back in for free support under "customer good will" by saying "if this works, we may want another dozen."

JMW

http://www.ViscoAnalyser.com