Simple Solutions That Work! Issue 17

CLOSED-BACK (TRADITIONAL) TEAPOT SPOUT In the closed-back design, the shell behind the teapot remains in place and the teapot spout is effectively an add-on to the ladle. This design however, presents significant challenges when it comes time to reline it. Back in the day, the size of teapot spouts in the UK was set by the size of the fire brick available. A teapot spout could be created using specific firebricks. However this changed when castable refractories became the standard lining method for ladles. With a castable lining, this creates a refractory/steel/refractory sandwich behind the teapot spout, which can result in a large heat sink (possibly far more so than firebricks). The lining allowance for a refractory needs to be greater than with a firebrick. Whereas an 1-1/2” (38mm) may have been acceptable for a fire brick, a castable might need 3” (75mm) lining. The spout is both difficult to line and clean. When it comes to cleaning/maintaining the spout lining, it can result in the whole ladle lining needing to be wrecking out. As the teapot shape provides a good anchor for the castable refractory, wrecking out the lining is likely to be labor intensive and require the use of pneumatic hammers etc., all of which creates health and safety issues. The steel reusable lining former for this type of ladle is typically a multi-piece unit, which is expensive to manufacture and difficult to use. Contact: STEVEN HARKER steven.harker@acetarc.co.uk PRE-CAST LININGS Having an open-back teapot spout ladle allows the foundry to use pre-cast, or pre-formed lining systems, which are easy to remove. This significant advantage is the main reason foundries prefer the open-back teapot spout ladle. RELINING Relining a ladle takes special skills. When it comes time to reline your ladles, (which likely occurs several times during the year), you need to ask several questions: • Is the lining material still within its life? • Has it been stored correctly? (Both an important factor due to the harsh environment inside foundries and an important detail if your outside ambient temperature can reach 80-90³ F.) • Do the people doing the relining have the necessary skills and equipment? Many foundries prefer to have this performed on-site (either by your staff or an outside firm), as the removal and replacement time is reduced and the ladle can be back in service that much quicker. I’d like to thank the kind folks at Calderys (UK) and Refractory & Insulation Supply for their wisdom and photos regarding pre-cast liners. OPEN-BACK TEAPOT SPOUT With the open-back design, the shell behind the spout is removed so that the ladle shell and teapot spot become one fabrication. The ladle shell may need additional external bracing to maintain the structural integrity. In this design, the lining can be cast as one piece and the teapot is created by the inclusion of a suitable refractory plate. This removes the sandwich, which eliminates the possibility of a heat sink. As the board is typically held in place by refractory mastic, it can be removed and replaced without the need to wreck out the whole lining. The steel re-usable lining former is a one-piece fabrication, making it both easier to use and also very cost effective. 8