Cascade Bowl (Spout)

8/11/2019 Cascade Bowl (Spout)

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After a little more thought, we decided to keep to a simpler shape with more hori(ontal andvertical surfaces. )e considered that this design would !e ust as e*ective, and that the wider!owl entrance was not needed, due to the introduction of the -0/ shoulder.

Des()n Mo&ell(n)At this stage, phsical models of the standard and the cascade !owls were constructed, in two

depths, and studies were made of their &ow characteristics. From this work, the !ene"ts for glassconditioning seemed to !e greater with the deeper design.

%he studies showed us that, with the standard !owl, glass entering the !owl near to the surfaceis pulled round the !owl ! the tu!e, and its temperature can onl !e a*ected ! the !owl "ringas long as it remains near the surface.

lass entering from the !ottom of the channel uickl moves awa from the "ring and loses heatto the generall under insulated !ottom of the !owl entrance.

)ith the cascade !owl design , glass from all depths in the channel remains closer to the surfaceuntil well into the !owl, and will therefore !e !etter controlled. As the glass moves around the

!owl, it slowl moves downwards until it enters the lower well.

%he cross section of this lower well is smaller than in the standard !owl, and so the glass fallsfaster. %he time taken for the glass to move through the lower part of the !owl is much shorterthan in the standard !owl, less heat is lost ! the glass and temperatures will !e more uniform.

%his ta!le summari(es the changes in glass residence times for the two designs of !owl. %heresidence times in the lower (one or well2 of the cascade !owl are much shorter than in thestandard !owl. %hese shorter times would reduce the conduction heat losses, and the resultingtemperature di*erences would !e smaller.

Res'lts from Factor* r(als%he "rst cascade !owls were installed on colored glass feeders in the container industr, andthese feeders are still operating with the new !owl.

%he "rst cascade !owl was installed in 3.4.5. 6edfearn, $arnsle, ngland in 8ecem!er 1991, andthe net two in :aint+o!ain, ;aurot, France in late 199 hotter in the

cascade !owl and the di*erences around the !owl were reduced.. %he lower "ring level used in the !owl reduced the amount that the glass reheated as it

moved around the !owl. %he reheat for the standard !owl was reduced to 1 in thecascade !owl.

@. 8uring a ver long o! change on the cascade !owl, glass fro(e in the ori"ce ring and ittook a long time to melt out. $ut after the glass was &owing, the go!s !ecame sta!lemuch uicker.


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?. %he tu!e speed could !e reduced without signi"cantl changing the go! weights. Areduction in speed from 10 rpm to ? 635, caused the weights of the go!s to change !onl old glass in the !owl entrance was eliminated, with the top+to+!ottom temperaturedi*erences !eing reduced from 10?/> to


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)ith the standard !owl the maor control volume is the gap !etween the tu!e and the tu!e seat,!ut with the cascade !owl there is an additional resistance within the annulus outside the tu!eand inside the well. %he e*ective viscous resistances of these regions can !e calculated usingstandard euations, and from this the relative &ows can !e determined.

%o compare the operating conditions for a cascade !owl with a standard !owl, it is necessar toeuate the relative tu!e heights for the same &ow rates.

)e "rst had to ensure that, to maintain the maimum pull, the tu!e height would not have to !eraised too much.

Dsing a tu!e height of @0 mm 1.?E2 as a reference point, we calculated a well diameter whichwould ensure that the tu!e height would not increase ! more than 10 or @ mm2. %his choiceof reference point ma seem to !e purel ar!itrar, !ut if a di*erent reference height had !eenchosen then a di*erent E increaseE value would have !een used.

If this predicted movement in tu!e height is too small, as would !e the case for a ver large welldiameter, then the thermal and &ow !ene"ts of this design would !e signi"cantl reduced.

%he upper (one depth is normall "ed at 1?0 mm -E2, which matches the standard forehearthglass depth.

%he upper (one diameter is chosen to ensure a shoulder width around the well of !etween 7?and 1


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%his concept could, euall, !e applied to the manufacture of tu!ing, ta!leware, %.;. tu!es andlamp !ul!s. ver!od is striving for greater consistenc in glass temperature and &ow rates toimprove their production eciencies. %his design has shown that it has attri!utes which are!ene"cial, when applied speci"call to the container industr.

I have shown how an idea, which is "rst rationali(ed on paper, is assessed using modellingtechniues. A prototpe design is then tested under glass, and "nall a famil of similar productssuita!le for most customer's needs, is developed.

%o conclude, I would like to thank the customers who helped us in the initial assessment of thisnew concept. I feel that their need to improve their processes, plus the potential !ene"tsindicated in the modelling studies, ensured that we were allowed to test the cascade !owl underglass.

5ike :tanle, $.#.+F.ngineering2 4td.1

Cascade Bowl (Spout)

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