Omega Castings, Inc.

Return rolls are similar to hearth rolls in that tube dimensions and trunnion selection are the same. However, return rolls have an added supporting tube that contacts the belt. Return rolls can be produced in two different ways. The first way has less upfront costs and consists of using two short tubes with tube supports at each end to support the center support roll. The second method uses a two-piece design where there is one center tube, which supports the larger supporting tube. The benefit of the two-piece design, while somewhat more expensive to produce initially, is that if either tube should be damaged (i.e. broken trunnion or distorted contact tube), the unit can be repaired at less expense than replacing the entire roll. Return rolls should be used on any cast link belt in excess of forty eight inches wide and, of course, some forty eight inch belts are also returned on return rolls instead of skid tiles.

The ability of a cast-link belt to move uniformly and accurately through the furnace hearth is, in great measure, dependent on the quality of the drive drum. The engagement of the drive drum teeth against the belt links must be equal across the width of the belt to assure uniform stress per link and provide proper tracking of the belt. We have been critically aware of this problem from the first drums we produced and, thus, have always profile ground the rows of teeth so that all of the teeth in a given row will engage the belt properly for uniform stress and guidance.

Omega Castings only uses the highest quality alloy pins for assembling our belts. As new alloys become available, we are constantly evaluating them to determine if they are upgrades to our current product line. When we establish an alloy is a better value, we immediately start recommending it to our customers so they can take advantage of it as soon as possible.

Sometimes there just isn't an off-the-shelf solution or the supplier you used to count on is no longer available. If you need a custom casting or assembly for your high temperature application, Omega can help. We have a history of producing custom castings to fit the needs of our customers. From fingers that move cast-iron pipe through a furnace to hanger assemblies that carry radiator assemblies, we can work with you to develop a solution.Â

The P-448 is a four-inch pitch, three-inch-wide link and is assembled using a three-quarter-inch diameter pin. By test, this link is the strongest of our four-inch pitch group and fractures under load at room temperature at thirty-five thousand p.s.i. Mode of failure is fractures through the end bearing walls. These links are machined through the end bearing holes to remove draft and establish a true in-pitch surface for pin engagement. The links, when assembled, have a twenty-thousandths clearance with adjacent links at room temperature and a twelve-thousandths clearance at operating temperature.

The vast majority of idler drums used in cast link belt furnaces today are eleven inches in diameter and are smooth on the contact surface. Because their main function is to support the cast link belt on the charge end of the furnace and provide “take-up” pressure to the belt, the smooth surface is desired. If the belt is not stretched more on one side than the other, it should remain centered over the idler drum. If the belt is not uniform, if some hearth rolls are not aligned perpendicular to the belt or if some hearth rolls are not level, the belt will track to one side or the other. This can only be seen if the idler drum is smooth, thus it is the warning alarm that something is not right and must be fixed. Some furnaces are