Two Elevators and one conveyor
The drawing was made c.1906 while the reference book I have was published in 1922. I assume that there may have been a change in describing conveyors and elevators during that time as what are labeled Conveyors on the drawing are obviously termed Elevators in the reference book..
There are two Belt Elevators shown in the drawing – with a third Belt Conveyor apparently feeding the Washed Coal Bin. That one I will leave alone for now (I did notice that it is a flat Belt Conveyor unlike the two Belt Elevators. For now I will pay attention to them.and pay attention to those two.
In 1979’s Extraterrestrial Civilizations, Isaac Asimov estimates the probability of there being intelligent extraterrestrial civilizations within the Milky Way galaxy. This estimation is approached by progressively analyzing the requirements for life to exist. In this book Isaac often referred back to the “Theory of mediocrity” — The mediocrity principle is the philosophical notion that “if an item is drawn at random from one of several sets or categories, it’s likelier to come from the most numerous category than from any one of the less numerous categories“.
I will use that principle as interpreted by Isaac that with a single source to choose from .. such as the drawings of these Belt Elevators — that that IS the most numerous example .. being the only one .. so unless convinced otherwise will go with these as being correct.
|Carefully scaling the Belt Elevators in the drawing (I used the larry on the far right having a good, scaled model of that same larry design.
Some early thoughts:
The dimensions are shown below – the idea is to use those numbers to try and get a better design using Belt Conveyors and Belt Elevators by Frederic V. Hetzel, M.E. pub 1922
Overview – of a sorts
Belt Conveyors and Belt Elevators goes into excruciating detail. I don’t need all of that .. just enough information to create a reasonable replica in scale. So for now .. I will just pull excerpts from the book .. simply gathering information for the now .. much like collecting mushrooms in the forest and only later tossing out the ones that will poison you.
At this point I stopped to consider the drawings of the two Belt Elevators. Some make take exception to the buckets are drawn and our take from said drawings. Yes the draftsman may have simply simplified or misunderstood what he was attempting to portray but .. we have to use the ‘Theory of Mediocrity’ — I will use the acronym TOM from this point on .. and simply go with what we have.
Early classification of the two Elevators: If we base what kind of Belt Elevator we have on the spacing of the buckets then I would at this point classify the Crusher Belt Elevator a Continuous Bucket Elevator based the 2″ gap between buckets. I would classify the Washed Coal Belt Elevator as a Centrifugal Discharge Elevator based on the 15″ gap between buckets.
(page 210) Discharge at the Head. — In some forms of chain elevators the buckets discharge on the lift, but all belt elevators the buckets discharge at the head into a chute set to catch the material, either as it is thrown out by a centrifugal discharge elevator (Fig. 200) or as poured out by a continuous bucket elevator (Fig. 201).
Note: On page 212 there is a discussion of head wheel diameter, RPM and belt speed for centrifugal discharge and a Table 35. This may not be necessary information but I put this as a marker in case I need to refer back to it. (in the discussion, a centrifugal discharge elevator is one that runs at a speed high enough to discharge the contents of the buckets clear of a vertical run of descending buckets. At this point I am going to jump around to estimate the head wheel (pulley) diameter, RPM and belt speeds for the two elevators.