Impact rollers

Impact rollers

"Impact rollers" are the idler rollers installed in a belt conveyor in the area where the bulk material is fed onto the conveyor belt. 
These rollers are generally subject to high loads: they not only carry the conveyor belt and the bulk material, but also absorb the forces of the impact of the bulk material on the conveyor belt.

To dampen the impact forces, the impact rollers are usually equipped with impact rings made from rubber. The impact rings are often also called buffer rings.

If the loads are particularly high, a hot-vulcanized rubber coating is used instead of the impact rings. 

In the case of extremely high loads (e.g. individual lumps weighing up to 1 t at a feed drop height of >5 m), even the highest quality rubber coating cannot withstand the impact forces for long time without additional constructive measures to dampen them. In extreme cases, it is therefore better to dispense with any kind of rubber coating on the impact rollers and at the same time take other constructive measures to dampen the impact forces (see feed garlands, heavy-duty feed garlands).

Detailed information on the dimensions of the rollers can be found in the chapter "Dimensions and designs".

Comparison of quality classes of impact rollers

We have defined three quality classes ("Compact", "Compact Plus" and "Premium"), which we recommend as the optimum solution depending on the specific application. Each quality class corresponds to the type of operating conditions on site and the requirements on the rollers.

Roller tube
Tubes	Welded cold-sized steel tubes acc. to EN 10305-3	Welded cold-sized steel tubes acc. to EN 10305-3; with restricted tolerances (Küpper Standard)	Welded cold-sized steel tubes acc. to EN 10305-3; with restricted tolerances (Küpper Standard)
Material	Steel S235JR acc. to EN 10025-2	Steel S235JR acc. to EN 10025-2	Steel S235JR acc. to EN 10025-2
Bearing housing
Type	Deep-drawn part	Forged part	Forged part
Materials	Steel DD13 acc. to EN 10111	Steel C15 acc. to EN 10267-2 or S235JR acc. to EN 10025-2	Steel C15 according to EN 10267-2 or S235JR according to EN 10025-2
Bearing seat	IT7	IT7	IT7
Shaft
Type	Solid shaft	Solid or bending-resistant hollow shaft	Solid or bending-resistant hollow shaft
Materials	Round bar steel acc. to EN 10277	Round bar steel acc. to EN 10083-2 / Tube acc. to EN 10305-3	Round bar steel acc. to EN 10083-2 / Tube acc. to EN 10305-3
Bearing seat	IT9	IT6	IT6
Bearing
Make	AKT	AKT	AKT
Bearing type	Deep-groove ball bearing	Deep-groove ball bearing	Deep-groove ball bearing	Spherical roller bearings
Bearing sizes	6204 - 6305	6306 - 6312	6310 - 6318	21310 - 22318
Sealing	2Z	2Z	2Z	-
Bearing clearance	C4	C4	C4H	C3
Tolerance classes	P0	P0	P5	P0
Cage	Plastic cage	Plastic cage	Plastic cage	Sheet steel cage or brass cage
Greasing	50 - 60% of bearing´s free internal volume	50 - 60% of bearing´s free internal volume	Customized solutions
Seal
Seal type	QLR hybrid seal	QLR hybrid seal	QLR hybrid seal Weather shield
Running characteristics
Total Indicated Runout (TIR) [mm/m]	-	-	≤ 0,2
Impact rings / coating
Type	Impact rings or hot-vulcanized rubber coating	Impact rings or hot vulcanized rubber coating	-
Material	Rubber	Rubber	-