Roller gates are horizontal steel cylinders with toothed gears provided at each end. Racks are placed in the piers along the track recesses. These gates are mainly used, where large masses of floating ice and low temperatures used to hinder or even block the operation of conventional gates. These are generally used on low head dams and in installations where a wide opening between piers is desired for the passage of ice or debris.

In furnace of this type, water-cooled rollers through a long, straight heating unit move the workpieces. These are extensively used in the heat-treating of plates and other types of workpieces and, more recently, for reheating slabs immediately after they have been continuously cast. A furnace of this type, with a high thermal head, is used to heat slabs prior to their reduction in a planetary mill. Main burners above and below the pass line heat the slab through the top and bottom surfaces and auxiliary burners fire through the sidewalls in line with the slab edges to supply additional heat to the edges and corners. It has the ability to handle very long workpieces with little danger of mechanical damage. Skid marks are avoided due to the uniform motion of the workpiece through the furnace or a back-and-forth rocking motion produced by the rollers.

Roller mill is used in pregrinding or finish grinding of materials. The material between the rolls is submitted to a very high pressure ranging from 100 to 200 MPa. During the grinding process, partial breakdown of the grains occurs and there is a partial formation of incipient cracks in the interior of the grains. The material leaves the press in the form of agglomerates. When the roller press works in the closed circuit for finish grinding, a disintegrator must be used or a special separator must be installed to deglomerate the product. Frequently the roller mill is applied for pregrinding with the ball mill as a second stage. Roller with individual hydropnuematic spring systems provides a very smooth and almost vibration free operation for the mill.