Re: Solids Mass Flow Measurement
Robert
I have a way to measure the solids flowrate using a special designed turbine device. The turbine is installed in a vertical standpipe. The device is simple and has a relatively high accuracy.
An article appeared in Powder Technology gives a description of the protype of the device: JingyuanLiu, Bowen Huan, “Turbine meter for the measurement of bulk solids flowrate”,Powder Technology, 82, 145-151(1995).
I had more tests in IRL, New Zealand with Dr. Clive Davies. The tested materials included sand, plastic pellets, wheat, urea pellets, rupin seeds and so on. It performed very well.
Jingyuan Liu ■
Re: Solids Mass Flow Measurement
Hello Bob
What about using load cells to measure the mass in your feed or exit bins ? This can give you mass flow rate averaged over say 1 minute.
Regards
Mark Kilfoil
Mechanical Engineering, Technikon Witwatersrand, South Africa ■
Untitled
Mark,
Thanks for the reply. I didn't make myself clear in my question. I have two flows entering a vessel. I need to know what each flow is in order to control the recipe used to make each flow. This is Polyethylene and the flows are from extruders. We use the flowrate to control the recipe in the pellets being made.
The vessel the flows are going into is on load cells, but that doesn't help when I have two independent flows entering the vessel.
The vessel is very tall so I don't want to put a very important measurement instrument up ~120 feet in the air. The maintenance on the instrument would not be adequate.
So, my need is for a flow meter as I described, in the conveying line going to the vessel. ■
Re: Solids Mass Flow Measurement
Hi Bob could you look at Pfister web tehe produce a metering system wit dense phase trasportation the web is www.pfister.de
best regards. ■
In Line Flow Measurement
Hi Bob
Thanks for the clarification. I have some ideas but they need work (R&D). Unfortunately that does not help you.
Regards
Mark kilfoil
Mechanical Engineering
Technikon Witwatersrand ■
Re: Solids Mass Flow Measurement
Bob,
Tough application in a horizontal line. Vertical up or down I might be able to suggest something.
An alternative to consider, would be measuring from your source rotary valve feeding into a conveying line, you could get the speed and estimate and calibrate fill efficiency over the range, accuracy would be greater than 10%. It will be a rough number to get you started. Possibly loss in weight of the unloading bin.
Another possiblity would be inline mixing of the two feeds in the ratio you are looking for, again it would depend on the upstream equipment feeds.
Sincerely,
Mark O'Rosky ■
It Could Be Vertical
I can consider installing this in a vertical position going up, not going down. The pick up point at the classifier is at grade and the discharge point is at 120 feet. What ideas do you have?
I cannot live with 10% accuracy, I am looking for 1% or better.
Thanks for the feedback.
Bob Sander
robert.sander@bpsolvaype.com ■
Re: Solids Mass Flow Measurement
ABB have solids flowmeters currently being fitted into coal fired plant in Europe and the USA. These are typically 17" diameter.
Small diameter versions 40mm dia are operational at the coal research labs of Cassella Ltd at Stoke Orchard near Cheltenham, UK. Contact there is Brian Armstrong. Brianarmstrong@cassellagroup.com
4" versions have also been tested.
Contact at ABB is Ray.Keech@Gb.abb.com
ABB Ltd
Oldends Lane
Stonehouse, Gloucesteshire GL10 3TA, UK
J Coulthard ■
Re: Solids Mass Flow Measurement
Hello Bob,
You mentioned that you are using two extruders to provide the source for a blended pe stream for your pelletizing line. Are these extruders equipped with head pumps? If so, you should be able to monitor both extruder output masses and use the combined value for your throughput mass flow rate (assuming no loss of mass from either of the two pe input flows).
Regards, ■
Use Of Melt Pumps
Thanks David.
No, neither of these extruders have melt pumps on them to use as mass flow meters. I am familiar with this idea on other lines in our plant.
In the meantime, I have elected to use old technology to solve my problem. I am going to use weigh belt feeders to meter the solids flow rate. ■
Re: Solids Mass Flow Measurement
Bob,
The weigh belt feeders will work well and provide a good tolerance (well within 1%) as long as you do not have spillage after the weighing process.
Good Luck with your process control upgrade (old technology can be better than new). ■
Solids Mass Flow Measurement
I am in need of measuring the mass flow of HDPE pellets in a dilute phase air conveying stream. I know of mass flow meters from vendors such as Ktron that require a solids stream in gravity fall. However, I do not have a convenient place in my process to install such a device.
I was wondering if anyone knows of a vendor of an instrument that could measure the mass flow of the polymer stream when it is in a pneumatic conveying line moving at 4000 -6000 feet per minute. The transfer line is 4" diameter and I am conveying from 10-20,000 lbs/hr.
Thank you for your help. I am located in Houston, TX USA. ■