Unibridge Steel Ribbed Neck Silo Bolts Hot Dip Galvanized self locking Bolts 4 Rib Under Head Plastic Capped fine Neck Mushroom Head Water proof

What is a silo bolt?

To those in the business, this describes a very specific type of bolt, used to bolt the glass fused to steel panels together in silos and slurry stores.

​These bolts were originally used in silos, because the low profile head helped the material flow throgh the silo, hence they are not normally known as tank bolts even though this is now a very common use for them.

The technical term is a ‘Cup nibbed bolt’ or a ‘Cup finned bolt’. The nibs (or fins) are small burrs on the junction between the head and the shank, which bite into the glass surface and allow the nut to be tightened without having to hold the bolt head. ​These bolts are also used in bolted tanks for waste liquids, leachate, digesters and digestate.

The bolt head is encapsulated in plastic for added corrosion resistance. This plastic is safe for food use. When used correctly, these bolts resist strong acids as well as alkalis, covering a pH range from 3 to 10.

The plastic cap on the bolt is normally one colour for a certain length, allowing easy identification of the length of bolt used in various positions in the silo or tank;

When a silo or tank is rebuilt, all bolts, nuts and washers should be replaced as a matter of course. Using old bolts and nuts wastes time, and interrupts the rhythm of a good erection team. Replacement is fairly straightforward

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All silos and slurry stores should be inspected from time to time. We recommend every five years. * The most common fault with silo bolts will be degradation of the plastic cap due to UV light. This frequently occurs in slurry tanks, usually affecting the heads of bolts in the top ring(s) only, as these are not always covered with the slurry. This will be noticeable after about 15-20 years.