Question
Hello Professor,
I have been asked to locate a meter for use in liquid propane with a flow rate of 1/4-1 gallon per minute. This is for the U.S. market (350 p.s.i. max). Any suggestions? Thanks, Ed

Answer
About the best meter for this would be a Coriolis meter. You will probably need to look at a .25 inch meter. Another meter selection would be a small turbine meter.

Best Regards,
Professor

Question
Hi there,
My name is Kiki and I am studying computing and electronics in London.My final year project is based on digital flowmetering.I would like to receive some feedback from you ,if it is possible, so I will be able to construct my own flowmeter and of course get my degree.I m interested especially in the digital part of the device that i need to construct.I include my project proposal in this email so you can understand the required and send me back suggestions or even any idea..

Thank you in advance,
Kiki

Answer
Dear Kiki,
I did not receive your project proposal to fully review all of the intergration that you will be doing. However, I would start with some of the higher level things, such as researching the obvious,

API (American Petroluem Institute) MPMS (Manual of Petroluem Measurement Standards) Chapter 21, Parts 1 & 2. These Standards are used by the Oil & Gas industry, and other industries as a guide for data security and quality of data from an electronic flow meter.

ISA (Instrument Society of America)

Make sure you have a quality primary device, accurrate secondary devices, and your digital recording device, or tertiary device, meets the requirements of a Standard. Depending on the technology you are using the secondary device may well be the tertiary device as well. Make the outputs usefule to the users. Understand the field of practice that you will be helping.

Best Regards,
Professor

Question
We, XYZ Exploration & Production Incorporated, are one of the largest oil & gas producers in our area We are analyzing the suitability of Daniel Orifice Fittings according to the XYZ Double isolation Procedure. The basic intent of using double isolation arrangement is to provide energy isolation i-e isolating and depressurizing the equipment or instrument for maintenance jobs. The arrangement is for energy isolation and will have live pressurized system on one side and depressurized system (near atmospheric pressure) on the other side.

In scent of above we have following query,

1. Does the Orifice plate is replicable in Daniel orifice fitting in live pressurized system. If this is, so please provide a reference and procedure from manufacturer for replacing the orifice plate from fitting safety.
2. If the orifice plate is replicable in live pressurized system, then please provide us the details of sealing arrangement, and also provide the procedure for finding out the integrity of sealing between live pressurized system to atmosphere.

Early response in this matter is highly appreciated, as this is a case if safety concern.

Answer
Dear XYZ Company,

Without knowing the specifics of your installation, I am assuming that you have a senior type orifice fitting, which allows the removal of the orifice plate while the flowing stream is under pressure, or "live." You might try going to the Daniel website and downloading the Installation and Operation manual from the following link:
http://www.daniel.com/products/gas/orifice/senior/productdetail.htm

In addition, I would contact your company measurement group in Houston.

Best Regards,

Professor Flow

Question
Would you know where I could pick up a fairly cheap venturi principal valve to attach to my ir compressor for using as a vacum pump in my woodworking shop?

Answer
As a wood working buff myself, I would recommend that you get a vacuum system for your shop. It is more energy efficient. If you have not yet finished your shop or are looking to modify your shop, there are several excellent books on setting up woodworking shops that can be found on the internet, or from a good book store.

Best Regards,

The Professor

Question
Dear Mr. Professor Flow,

Hoping you are well and Happy New Year.May I ask you humbly to furnish me with the complete comparison table of all flow measurement methods ?

Thank you in advanced,I remain.

Best regards,

Answer
There is currently work being performed by ISO Technical Committee 30 to develop a document titled "Guide to the Selection of Flowmeters." At this time, I do not know when it will be available publicly.

Flow measurement device selection is a complex function. Improper selection of a meter can result in loss of revenue, poor performance of the meter and other equipment relying on the meter for performance data, damage to the meter and equipment relying on the meter data. Below are some of the more important considerations that effect the selection of measurement devices:

1. Fluid properties

2. Performance requirements (Custody transfer, allocation, or operational)

3. Environmental (ambient conditions)

4. Installation and Maintenance

5. Economic considerations

Each of these areas require numerous factors to be considered when selecting a meter. All of the factors for selecting a flow meter need to be looked at interactively.

I will supply a link to where the ISO document can be found once it becomes available.

Best Regards,

Professor Flow

Question
Professor:
Can you please explain (in very simple terms) what a flowmeter does and what could happen if one did not work correctly - in particular, for gas, liquid and slurry applications?

Your help would be greatly appreciated!!!

Answer
A flow meter is a device that measures the volume or mass of a fluid, liquid or a vapor, that is conforming to the shape of and flowing through a conduit (pipe, ducting, ect...).

Improper selection of a meter can result in loss of revenue, or on the flip side, gain of revenue (which when audited you will be liable for), poor performance of the meter and other equipment relying on the meter for performance data, damage to the meter and equipment relying on the meter data.

Hope this has helped.

Professor Flow

Question
Professor:
I wonder if you could help. I have read some text regarding the flow mechanics of fluids and the venturi effect, but there is still something I don't understand about the venturi effect. I am planning to install a venturi into our main water supply for use of fertigation. According to the venturi principal, the output pressure will be the same as the input pressure; the pressure will only change in the venturi itself (since the product of velocity and pressure stays constant throughout the line). But I see the the venturi as a constriction, almost like a valve, which should case a pressure drop at its output, since it should have the same effect a valve has when you close it half way. Also, how can one calculate the flow rate? I can measure the pressure at the input and output line, but not in the venturi itself. I would appreciate any advice.

Thanks
Answer
You do need to measure the pressure in the throat of the Venturi to properly calculate the flow through the device. For water, which the expansion factor of 1.0 (Y1) the following equation could be used:

A drawing of a Venturi meter is shown above. The Venturi meter was invented by the Italian Giovanni Venturi in 1797. In a Venturi meter there is first a converging section in which the cross sectional area for flow is reduced. Then there is a short section at the reduced diameter, known as the throat of the meter. Then there is a diverging section in which the cross sectional area for flow is gradually increased to the original diameter. The velocity entering the converging section is where the pressure is P1. In the converging section the velocity increases and the pressure decreases. The maximum velocity is at the throat of the meter where the minimum pressure P2 is reached. The velocity decreases and the pressure increases in the diverging section. There is a considerable recovery of pressure in the diverging section. However, because of frictional effects in the fluid, the pressure leaving the diverging section is always less than P1, the pressure entering the meter. Venturi meters are very efficient however, and typically have discharge coefficient Cd values greater that 0.95.

I sincerely hope that this helps to answer your question.

Professor Flow

Question
Professor:
I'm hoping to find a suitable flow meter for the measurement of Hydrogen Peroxide. The flow rate is very small; 30 - 200 mls/min. We have a pulsing flow so we may be limited to a positive displacement meter. Any suggestions would be welcome,

Thanks

Answer
You may want to look at using a Coriolis meter. There are several manufactures of this type of meter. I would suggest this type of meter due to its accuracy and the density of your fluid is very stable.
Some of the manufactures I would contact would be

• Emerson (Micro Motion)
• Endress & Hauser
• FMC
• Foxboro
• KrohneABB

Regards,

Question
Professor:
I' m trying to find the standard AGA7 publication for fuel gas measurement, but I still can't find it anywhere. Can you help me?

Answer
Try going to the American Gas Associations website at: http://www.aga.org. If you have trouble finding it from there, please send me another email and I will have the direct link to the page for you to order the document.

Have a happy holiday!

Professor Flow

I need a flowmeter and I know nothing about flow meter manufacturers.

I need an off-the-shelf instrument to monitor gas flow in a 1" pipe, arround 200 cfm. (no rocket sicence here!) The little ball in the glass tube type would work, but since I need to remotely monitor the flow, I need something electronic. Who is the best manufacturer of electronic flowmeters, in terms of product reliability, working out of the box, prompt delivery and ease of setup? Now that I wrote it, hopefully there is one manufacturer that does all of this. I listed these in order if importance, in case a manufacturer excells in a specific area.

Thanks for your help.

First let me ask what type of service are we talking about here? Gas lift in a harsh environment or a gas lab in a clean environment? What pressures are you dealing with?

For low pressure applications, you may want to use a positive displacement meter, with a readout device that has been fitted with a 4 -20 ma output. These would be my first choice for out of the box reliability.

There are some new small ultrasonic meters that are on the market that you may want to investigate that are for LOW PRESSURE ONLY. These meters are used sometimes for measuring gas into homes.

Both of these options can be remotely monitored.

Hope this has helped.

Professor Flow