I want to know if vibration's on a gas line can alter sensing accuracy of a Coriolis flow meter.

We have one Emersons Micromotion's flowmeter installed near to a Gas Turbine's enclosure, maybe to 6 o 8 feet measured from enclosure's wall. We have appreciated that vibrations over the gas line are strong even to be felt with the bare hand

Due to operation's principle of the flowmeter I'm supposing that this vibration can be altering the measured flow. The measured flow between our flowmeter and the flowmeter of the gas supplier (They have one Orifice plate flowmeter) are very different, even a 15%

Any information that someone can give about the topics will be fully appreciated

 

In the early days of coriolis this would be a serious problem. They were driven at really low frequencies where transmitted pipe noise and vibration could really interfere with the sensor. Higher frequency of operation means greater immunity to pipe noise. This is because high frequency vibrations tend to attenuate much more than low frequency.

Early coriolis meters were even sensitive to each other and would have to be detuned if two were to operate in close proximity.
Today you should expect much better filters and signal processing, much better better drive control and higher operating frequencies. However, having said that vibration levels in enclosed machinery spaces are a serious problem not just because of the frequency but also because of the amplitude.

If this were a ships engine then the Lloyds ENV1 and ENV2 approvals would be required. As an example, the Micromotion tuning fork viscometers (vibrating element sensors running at around 1kHz) are approved not just for enclosed machinery space built also for mounting on the engines themselves.

I'd strongly suggest talking with the manufacturer. I do know that coriolis meters are beginning to be used more widely on ships and there is serious interest in fitting in the fuel supply to the engines. It is therefore both historically justifiable to be concerned but realistic to expect to be able to install some modern sensors in high vibration environments... but check with the manufacturers.

 

It may could be that if your flow rate is low you are beyond the capability of a limited rangeability device like an orifice plate, and the Coriolis meter is correct. the only way to tell is to run the application (and installation) details by the manufacturer. Micro Motion also has an online community to receive help from a broader set of Coriolis users (http://community.micromotion.com/home.php).

Also, don't think that higher frequency Coriolis meters have a higher resistance to vibration issues in the field. Vibration typically runs through a wide spectrum and can hit at harmonic levels. For example a frequency of 200 Hz might also affect something running at 400, 800, or 1,200 Hz). A well designed meter keeps the active portion of the sensing element isolated from the vibration in the pipe through mechanical means, and has techniques for not allowing the drive frequency to be disturbed unless the offending frequency were within 1/4 Hz or less.

 

I have many years experience with the meter in question as well as that of another coriolis manufacturer. In my opinion, this is normally not the case with a few exceptions. Some models can have an issue if the pipe vibration hits a similar vibration point of the meter. There can be "spikes" of vulnerability although in my opinion the one you have is a very good meter. I can only remember one or two vibration frequencies where this would be the case. Again, I cannot speak for Micro Motion, I would suggest if possible to change the direction of your pipe. This may help with the possible vibration frequency issue. Coriolis meters are not susceptible to flow profiles like other meters so the straight run rule does not apply here. If you can do this, you may be able to change the amplitude of vibration if that is the problem. This is a not a cure all, but may help. Also, other manufacturers vibrate their tubes at different frequencies allowing for the elimination of this possible effect.

There are other considerations which may influence the difference you are seeing, and I would be glad to speak with you at any time.

 

Though I am not the expert with Coriolis Meter I believe that as this technology has vibrating tube so pipe vibration would be transmitted to the vibrating tube to add this vibration effect to read more pulses. There would be some measurement error which is very difficult to see on the meter but definately the meter would read high at vibrating conditions. The best way would be to calibrate the meter online or in the lab wherein the pipe is made to vibrate at the same load. This will give a good flow curve/flow co-efficient to produce quite accurate measurement.

I would love to know the performance of Coriolis Meter on high vibrating conditions.

 

Always follow the required straight pipe on both upstream and downstream side of the flow meter. I believe it must be 15X diameter from the pump on the upstream side. Also use proper pipe supports which is around 3-5X diameter on both upstream and downstream side. Vibrations must also be kept at 0.3G in order to acquire accurate reading.

 

Firstly I understand modern mass meters are far more conducive to high vibration environments and one of the applications they now target is fuel oil on board ships which means they must be suitable for the enclosed machinery space requirements which include not only high vibration but high G.

Second, it occurs to me we may be mistaking the issue here. What you note as vibration may actually be pressure pulsations.
Pressure pulsations can have a negative affect. This is due to the rapidly changing stiffness of the tubes. In bent tube meters the tubes tend to try and straighten out under pressure so pressure pulsations have been known to cause problems.

A great deal of work has been done on mass flowmeters focusing on software solutions to a great many issues. It is worth checking back with the manufacturer of your device.