With a wide variety of rolling motors on the market, choosing the right one can seem overwhelming. There are several factors to consider when selecting a rolling motor. Power source, torque control, RPM, torque range, and the style of the motor will vary depending on the application.
There are two motor power sources that are used for expanding tubes mechanically: electric rolling motors and pneumatic rolling motors. Determining what motor to use for a job will depend on operator preference, availability of electricity or air, and the application.
Expanding tubes after they have been welded can be frustrating for operators. If not rolled properly, tube material can build up and put stress on the weld. In extreme cases the tube material can build up so much that the expander can get stuck in the tube, delaying the job.
Tube Expanding is based on engineering principles, involving elasticity and plasticity, to compress the OD of the tube against a fixed container, such as rolling tubes into tube sheets, drums, ferrules or flanges. To assure a proper tube joint, the tube wall must be reduced by a predetermined percentage. The following chart can be used for determining the correct tube wall reduction.
Before you can start rolling, you will need to select the right expander for the job. Tube OD, and Wall/BWG will determine the size of the expander. However, there are some other factors to consider, such as tube projection, roll length, reach requirements, space constraints, and whether it’s minimum or average wall tubing.
Firetube boiler tubes consist of an expanded and beaded tube end. The method for achieving a bead has advanced over the years to include both hand beading and single roll beading expanders. In order to ensure a proper bead, there are several steps that need to take place before expansion can occur.
In general, you want to roll to the lowest wall reduction possible where a tight tube to tube sheet joint can be achieved. The harder the material the less wall reduction required to obtain a tube joint. You should always consult the manufacturer of the heat transfer vessel for specific information before undertaking any maintenance procedures.
Single roll beading expanders simultaneously expand and bead the tube ends in firetube boiler applications. This tool accomplishes the creation of a pressure-tight tube-to-tube sheet joint, and a beaded tube end, by utilizing the natural feed force built into the expander to push the beading roll against the end of the tube while expansion is taking place. The successful operation of these expanders can be achieved by following a few simple steps.
Elliott offers the 445 Series Motors in both roll and lever throttle for tube sizes 2.000” (50.8mm) to 4.000” (101.6mm) to suit your tube expansion needs. The powerful 445 Series Motors are ideal for tough boiler tube applications. The right angle heads are suited for rolling tubes in hard to reach, tight areas.
Tube Hole Gauges make it easy to accurately measure tube IDs and tube sheet holes found in vessels such as heat exchangers, chillers, and surface condensers.
