Solids Impact Flow Meter - Batches and Blend Combination Application
Ez-Flo Scales and Controls Do it All
Among other things, Duval Asphalt manufactures a seal coat for their customers in Jacksonville, FL. The sand silo they use to fill their mixer trucks had no means to weigh the sand as the sand discharges into the mixer truck. Dan Engle, General Manager, would like to batch into his trucks accurately at a controlled rate without emptying and raising the silo so trucks can pass under. Our order was to control the flow from his silo while weighing the discharged material in predetermined batches. Part of that required the control and weighing device fit vertically within the few feet of available vertical space. Of course, it had to be done within budget.
Our industry standardizes on expensive rotary valves (vane feeders) with gear boxes and variable speed motors to control flow. They are also big and heavy and in this application 18" high. Weigh Pods can weigh continuously in that type of application, but are big and expensive. Although considerably shorter than weigh pods, Flow Scales can also get the job done except they also have been too tall. Last year at this time, our Low Profile flow scale (Short Stuff) was featured in the News Rag in the Section ‘What’s on the Drawing Board’? Duval Asphalt was given the opportunity to be the first to try this under actual conditions in the field. This scale has a feature that no other scale we know of has. This scale is 10” tall. We designed Short Stuff for agricultural applications. Although shop tested, we were in no position to guarantee the results of our second-generation low profile scale.
Therefore, we provided Dan Engle with a Plan B; our Standard 26” Ez-Flo Scale with the understanding they may have to install the Standard under a raised silo. We took our design another step further.
Duval was discharging the silo through a butterfly valve full throttle. Instead of replacing the low profile butterfly valve with a high profile rotary valve, we proposed we modulate (vary the different positions between open and close) their valve to the rate they require their mixer trucks to be filled at.
When marrying the modulating butterfly valve on top of the Low Profile Scale and transitioned the output to a 10” boot, we were able to fit the entire weigh control system within the height restriction. The Butterfly valve control was our first attempt to make something like this work and it did a good job from the beginning. Our Second Generation Low Profile Scale was in trouble. We were having trouble calibrating it so it was consistently comparable to the truck scale. Before throwing the towel in, with the help of Tim, the company mechanic, we made a couple of small mechanical adjustments. And to our delight, these adjustments allowed the flow scale to perform beyond our expectations.
Watch Sand Silo Video - https://www.youtube.com/watch?v=Sw4Lz_8CAro
When thinking...Solids Impact Flow Meter, Solids Flow Meter, Continuous Weigh, Mass Flow Scale, Bin Depletion Scale, Dry Flow Meter, Belt Scale, Mass Flow Scale, Impact Flow Meter, Weigh Depletion Pod…Think Ez-flo.
Asphalt News Rag - 10