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A.F.M.S. Newsletter - December 1997 IssueP.O. Box 60426, LAFAYETTE, LA 70596 - PHONE/FAX : (318) 993-AFMS (2367) |
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AFMS has received a list (the membership
list) of deserving folks from a well known source! Those people and
a guest are offered a meal and fellowship on AFMS at Black's Oyster
Bar in the town square in downtown Abbeville. Such a good time was had
by all last year, we are repeating our Christmas party at Black's on
December 16 at 6 PM. Most of you should have received a fax memo invite
already. Hope to see everyone there! 
The November meeting topic "Advances in Flow Computer Archival Systems For the Gas Measurement Industry" was presented by CPU (Computerized Processes Unlimited) in Metarie. The time-consuming chore of editing can be eased by the use of a color coded calendar system, highlighting missing data and data outside the normal operating parameters for each individual meter. The use of the off-the-shelf spreadsheet programs seems common to several of these systems, making upgrades much easier. |
The long awaited booth packets for the short course on April 7-8, 1998 are out. Vendors not receiving a packet in a week or so might want to phone the AFMS line to check and see if one was sent and to where. One hundred and twenty one packets were sent. New vendors need let the Show Chairman Danny McFarland or Joe Petrie know they need one. As if they didn't have enough to do for the society, Danny and Joe stepped forward now to start the ball rolling. A call to the AFMS phone will let them know you need a booth packet. This year, the 77 booths inside the ballroom are $375 each, while the premium 20 outside booths are $425 each.
New and renewal members this month are: Frank Carpenter, Kippy Carpenter, David Mayeaux, and Mike Manson. |
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Just when you thought it was safe to go to your meter stations, another source of large error looms. The phenomena can occur in high pressure, high flow lines with obstructions, such as valves and manifolds. The errors can approach 4%, positive or negative. The effect can cancel itself out, with equal positive and negative effect. In such a case, raising the zero cutoff and using as small of orifice bore as possible would help. This looks like a good subject for a short course class or meeting topic. 
Look for a noon-time meeting in the spring, possibly to unveil our new website, due for commissioning in January 1998 as afms.org
Recent measurement articles.
1. "Flow Metering Changing", November 1997
1. "A Place for Signal Conditioners", November 1997. |
TIP OF THE MONTH QUESTION: Pulsation is suspected at a meter run. Is there an easy way to check for it and what can be done to reduce the effects if found? ANSWER: The vent and downstream tap valve are closed, while the equalizer valves and upstream tap valves are opened. This is similar to zeroing a DP under pressure except the tap valve positions are reversed. If the DP does not equal zero, pulsation may be present, especially if the DP varies. A method to confirm pulsation is to partially close an upstream valve near the meter run, but certainly before the pulsation causing device, usually a compressor or valve control device. By partially closing the valve, harmonics causing the error can be reduced or eliminated. The valve can be left partially closed to eliminate the error, but is not recommended for two reasons. 1) The valve will eventually be rendered useless. 2) A slight change in flow may cause the pulsation to reappear. The best cure is to eliminate the pulsation by moving the meter run or pulsation causing device. To reduce the effects of gauge line distortion, the use of large bore tap velves with equal lenght manifolds, such as direct mounts, can reduce the effects. Pulsation conditioners can be used, but since the harmonics can change, the conditioner cannot be assumed to always eliminate errors. |
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