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Week of 8 February 2021: Vertical Transportation

Email Jim at jim.thompson@ipulpmedia.com

Vertical transportation systems, that is, those which stack goods vertically, tend to occupy disproportionately more space than one would first think due to the need to have aisles to retrieve those goods in storage. From a floorspace allocation perspective, only half of the floor is devoted to storage, the other half is devoted to space for retrieval equipment to operate.

One system I have seen that overcomes this problem is a vertical storage finished roll warehouse. In this case, overhead cranes have special clamping devices that pick up vertically presented paper rolls with a system that clamps the roll around its circumference. In this warehouse, one can stack five 110-inch rolls vertically on top of one another, the equivalent of 5 story building. It is quite a system to see.

So, an entire order can be stack atop one another or in two or more stacks if required. Very little room is needed between the rolls in order for the system to work. What the system does require is an extremely flat floor--no leaning towers allowed here!

Such a system eliminates fork trucks for placing and fetching the rolls--a tremendous savings in transportation. It is also an excellent system for inventory control, for the computers operating the system must absolutely know where every roll is in order to fetch it, hence inventory control is very tight--automatically.

What I like about this kind of thinking is that it turns one's thought process on its head. If you have been around them, you know the myriad problems with fork and clamp trucks. From maintenance to operator training to motive power to potential for damage or accidents--such trucks have become legion for having problems. A solution that says we are are not having any of that is refreshing.

From a materials of construction standpoint, this solution uses materials in a way that takes advantage of their inherent properties, just like a cable-stay bridge does. Popular for the last forty years, cable-stay bridges employ concrete in compression (the piers and masts) and steel in tension (the cables). Concrete is strongest per unit weight in compression and steel is strongest per unit weight in tension.

The warehouse I described has a concrete floor to hold the load, admittedly a normal application, in compression. The rolls are lowered and fetched with a cable system (steel in tension) suspended from a bridge crane (necessarily of steel and in a combination of tension and compression, when one considers its lower and upper chords).

The latter part of the discussion here was a bit of a journey into the weeds, but from a cursory basis, confirms we are headed in the right direction from a utility of materials and economy perspective.

For safety this week, any time we can eliminate fork trucks, we eliminate a potential safety problem.

Be safe and we will talk next week.

________

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