Bucket Elevator
Dear Mr. Brown,
I definetly see where they are coming from in regard to explosions and fire risk/ due to static electricity build up. My feeling is that what should be done is to increase the size of the housings for the bucket elevators slightly to help reduce the potential for static build up. By enlarging the enclosure by a small amount this would allow for the use of copper grounding cables to be installed in the elevator compartment and allow the static charges to be bled off to ground through the housing and the cable as well. One sure way to help eliminate static electricity
in bucket elevators handling grain and flour is to install electric collector rings on the upper and lower elevator sprockets to channel any static electricity build up away to ground.
Please note:
A electrical collector ring is essentially a swivel that is used to direct electricity to a piece of mobile mining machinery- it can be used to bleed electricity away as well as long as the carbon brushes, springs and "bakelite" ceramic rings are properly maintained and inspected for wear/damage- these types of electrical controls have been in use for many years with much
success by mining machinery manufacturers all over the world.
This should work as any electricity even static electricity is lazy just like water, it will take the easiest path whether you are touching a doorknob or scuffing your sox on a carpet and touching a lightswitch. Any machine that rotates or contacts material has the potential for building up static electricity and a bucket elevator is an excellent example.
When I worked as a mechanic in a salt mine, the mining machines would build up small static charges due to their contact with the mine floor and roof unless they had a chain welded to them to bleed off the static electricity. A good example that will always stick with me is when I was about to refuel a roof scaling machine that did not have a grounding chain and I started to take off the fuel cap and I received a good jolt of static charge from the machine.
I would like to be contacted about becoming a moderator for this forum, thank you.
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Bucket Elevators handling Grain etc
It has long been known that
1) grain dust is explosive
2) bucket elevators handling grain have exploded
3) bucket elevators handling grain should have explosion protection.
I'm just reading the draft European standard prEN 14460 "Explosion resistant equipment" and the SCOPE will clearly include Bucket Elevators.
I note that
i) sections (5) and (6) include ".. prEN 13445 covering the design and calculations for unfired pressure vessles shall be used when dimensioning and manufacturing these vessels."
ii) section 6.2 includes "Equipment shall be pressure tested ....."
Bucket Elevators being designed to a pressure vessel code and pressure tested, that's a bit of a culture shock. Does this mean ALL machines individually tested or type testing, in house or by third parties?
Anyone got any comments about this? ■