Omega Castings, Inc.

he P-324 is a three-inch pitch, one-and-one-half-inch-wide link and is assembled with other like links using one-half-inch diameter pins. These links are used in furnaces with lighter load applications and, in many cases, for specific parts that require manual or robotic loading and unloading. This type of link was first used in the earliest cast-link belt furnaces (circa 1930's) and is still used in a number of smaller furnaces today. Various special-shaped three-inch pitch links have been designed for special purpose, all are used in solid belt construction.

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

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.

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 P-664-L is a six-inch pitch link slightly less than four inches wide and is assembled using a three-quarter-inch diameter pin. This link is a pintel variety, in as much as each link follows the preceding link in assembly. This type of link is used in solid belt construction, as well as "carrier belt" construction. Carrier belts are made up of single rows of links held in position with washers welded to the pins to maintain separation. Various numbers of rows of links can be assembled in a given belt, depending on the desired width of the final belt. Most rows are separated with a gap of eleven inches or less and facilitate a mesh belt overlay. The carrier belts are most used in draw or tempering furnaces, whereas the solid construction belts are used for hardening applications.

Omega Castings is the premier producer of alloy hearth rolls for the heat treat industry. We have achieved this level of quality by producing a hearth roll that provides the greatest value for the customer. We do this by manufacturing rolls in either a plug or tapered style with one-piece cast trunnions in the alloy most suited to the customer's application. Yet, it takes more than quality construction and alloy to make a hearth roll that is the longest lasting in the industry. We take the time to ask the right questions, such as: “What is the loading, application temperature, and atmosphere the roll will have to serve?” We then engineer our rolls so that, in case of power failure (or other issues causing the furnace to halt motion), our rolls can support the load, at temperature, without bending.