Masonry oven these primitive-looking ovens were still being produced in Barnstaple potteries as late as 1890". A cloche or cooking bell is like an upside-down, fired ceramic bowl with a handle on top. It is heated in the fire along with a flat rock or open spot on the hearth. The prepared dough is placed on the hot rock or hearth floor, and then covered with the cloche, and perhaps hot coals or ashes for additional heat. The method goes back to ancient Egypt and Greece, and was probably the first form of masonry oven. It is possible to get some of
Vacuum ceramic filter the system without further treatment. Filtrate is used to flush the disc during back flow washing to clean the micro-porous structure and remove any residual cake. One improvement over the standard design of ceramic vacuum filter is to use serialized pore size distributions of non-fibrous porous ceramic filters. The porosity of this type of ceramic can be varied from 20% to 60% by volume, which allows a low-pressure drop of liquid and gas flow. Custom sizes from 1 mm diameter/0.5 mm bore of porous ceramic filters are available for a range of designs. A non-fibrous porous ceramic filter is more