All cremation equipment, regardless of the manufacturer, is lined with refractory materials. By technical definition, refractory materials are substances that are resistant to heat. The term comes from the Latin refractarius meaning stubborn. The refractory materials used in cremation equipment are designed, not only to keep the intense heat required for cremation contained within the chambers, but also to retain as much heat as is safely possible to aid in subsequent cremations, saving fuel.
Even the most sophisticated refractory materials will wear out over time and need to be replaced since the refractory floor or hearth is subject not only to the intense heat of cremation, but to the abrasion of sweeping and cleaning out cremated remains after every cremation. It’s typical for the floor to be the first, and most common, area that is replaced in a cremator.
HOW OFTEN SHOULD A CREMATORY OPERATOR EXPECT TO REPLACE THE REFRACTORY FLOOR IN THEIR CREMATOR?
This question got quite a range of answers – anywhere from one thousand to five thousand cremations! Experts agreed that so much of the lifespan depended on the design of the units and the materials that are used. Determining the longevity of the floor (or hearth) is based on frequency of use, load volume, and remember that loading the case and removing the cremated remains causes abrasions. The average of the companies’ responses ranged from 1,250 to 2,500.
HOW LONG SHOULD ONE EXPECT TO BE OUT OF SERVICE WHILE THIS TYPE OF REPAIR IS COMPLETED?
Generally said, two full days – one for removal and pouring the new refractory, one for curing. Curing refers to the hardening of the refractory materials (poured to a minimum of 2½ inches thick) and gradually heating the materials to the temperature of a cremation. This timeline assumes that the machine starts fully cooled, and you may need to plan for an extra day depending on the kind of material and the size of the unit.
DOES THE MATERIAL USED PLAY ANY PART IN EASE OF INSTALLATION OF THE NEW FLOOR?
Cast and Cure manufacturers require an on-site, expert technician for the install. This ensures professional, quick, seamless work for a solid floor.
Pre-Cast Tile manufacturers may not require an expert technician (though some still recommend it) since the units are placed, not poured. This cuts down on install time since the floor is pre-cured as well.
IS THERE ANYTHING AN OPERATOR CAN DO TO INCREASE THE LONGEVITY OF THE REFRACTORY HEARTH IN THEIR UNIT?
Be gentle in loading by using rollers and in recovering the cremated remains with the right tools and method. Don’t use the rake like a garden hoe, but gently remove then brush – vacuum systems are preferred, cold air blowers are not.
Plan your day, or even week, ahead of time. A well-planned day saves fuel, labor, time, and your refractory floor. Cremate cases back to back, not one a day, and don’t leave the unit running if the case is done to minimize thermal shock on the refractory.
ARE THERE OPTIONS OTHER THAN FULL REPLACEMENT? PATCHES? PROTECTIVE OVERLAY?
Some manufacturers offer options to patch problem areas, particularly when using pre-cast tile floors.
Some decided to have a refractory overlay installed on top of the existing worn floor in one of his units to test the concept. Down-time is disruptive and avoiding large repair expenses for as long as possible is just good business.
Preparation for the overlay involved a jackhammer and a chisel to remove approximately 2 inches from the existing worn floor surface. Once the surface was ready, a high density 3000°F rated castable refractory product was mixed with water in a specialized mortar mixer and packed into shape on top of what was left of the existing hearth. Because the moisture in all newly formed refractory materials could vaporize and “pop” the refractory shape during the drying process, a slow gradual cure-out is necessary to assure the material sets up properly.
This procedure should only be carried out by an experienced refractory expert such as a crematory manufacturer or accomplished refractory technician.
There are many factors affecting the life of the refractory floor, such as cremator design, total case volume, actual refractory materials used, clean out procedures, and even the number of cremations performed in a day. One thing is certain; unless you have previous knowledge or skills working with refractory materials always seek the guidance of an expert for any repairs.
Refractory materials are also potentially hazardous and should always be handled in accordance with safety protocols and procedures. Most refractory materials contain aluminium, silica and magnesium oxides which are all known to cause respiratory problems if inhaled. Precautions must be taken to avoid this and only those trained in the safe and proper handling of these materials should be involved.
Source : A blog post on cremationassociation .org