Continuous research on new firing techniques to optimize the process.
The design of Equipceramic’s kilns is intended to have a long lifespan and robustness. They are built with dry pressed refractory materials, their walls are one-and-a-half brick thick (345mm) and they have suspended roof with an alveolar geometry. Refractory quality can be adapted to firing temperature, the type of fuel to be used and the chemical aggressiveness of clays.
The kiln is equipped with the required insulation so heat losses are reduced to their minimum expression. Layers of insulation materials are arranged to prevent the kiln exterior temperature from exceeding 20ºC, ambient temperature.
Equipceramic designs essentially two types of kilns:
TRADITIONAL TUNNEL KILN
Very robust kiln built with a traditional construction system whose efficiency has been widely proven. It is a safe bet. Brick masonry exterior walls can be adapted to the type of brick available to final customer. The kiln roof is also brick or concrete slab masonry built and it is provided with an automatic cooling system by means of a fan and a motor-operated damper.
No doubt, this is the type of kiln for most demanding customers. It is an evolution from the traditional kiln where the brick masonry exterior structure is surrounded by a welded steel enclosure, obtaining thus a complete sealing. Our particular design enables both the kiln to absorb expansions resulting from temperature and the firing canal to operate without pressure limits since its sealing avoids either leaks or unwanted parasite air penetration. Thanks to this particular design consisting of providing the kiln roof with a thicker insulation layer to eliminate any risk of leaks to the outside of the enclosure as well as ambient air penetration into the firing canal, the kiln roof cooling circuit has become unnecessary.
The installation of a prekiln is recommended for some brick manufacturing lines. It can be installed either in line with the kiln or parallel to it.
The prekiln ensures that ware is in the most suitable state for the firing process, by eliminating residual moisture, in the event of working with a rapid dryer, or by eliminating water regain when working in a discontinuous mode (week end stops or two working shifts/day). The installation of a prekiln is particularly recommended when using montmorillonite-type clay because its fine grain size increases its capacity to absorb moisture in the environment. Ware is introduced into the kiln in a completely dry state, allowing for the acceleration of the preheating process.
The firing process consists of three basic steps: preheating, firing and cooling, which are regularly subjected to innovation in our engineering teams’ willingness to better adjust their parameters and improve results.
PREHEATING AREA: it is aimed to preparing and preheating ware, as homogeneously as possible, before the firing area.Fumes:This section is provided with the suction outlets of the draught fan.
Preheating 1:Low-temperature section. Some air-recirculation fans are installed to minimize temperature variation between the top and the bottom of packages.
Preheating 2: Preparation section before firing. Some side burners are installed (when working with gas) having the same aim as the previous section, to avoid temperature stratification.
FIRING SECTION: The firing curve is adapted to the type of clay or to the required final quality standards.
Burners.Highest temperature section. Group-operated burners are installed to adapt the firing curve to the required quality standard. Equipceramic manufactures different types of burners depending upon fuel type.
Flashing. Final firing section where it is possible to obtain a shade variation effect on the surface of products by the installation of flashing group-operated burners. These ones allow for injecting fuel with an amount of air lower than the stoichiometric one.
Rapid cooling. High temperature section suitably equipped to resist abrupt changes. Some rapid cooling sets injecting ambient air and some high temperature recovery hoods are installed in order to reduce product temperature down to 650ºC.
COOLING SECTION: Product temperature is decreased in this section and exceeding heat is supplied to the dryer or to the prekiln to optimize specific consumption.
Slow cooling. A special care is devoted to products in this area since they go through a critical stage marked by transformation of quartz, 573ºC. Some waste heat recovery hoods are installed.
Final cooling. This is the last but not least important section of the kiln. Some waste heat recovery and ambient air injectors are inserted either on the top or on the sides, the aim being to reduce as much as possible the heat still remaining in the kiln car.