The roller kiln and the prefabricated oven with lighted carriages represent, under precise design conditions, a timely and integrated response to the request of a heat treatment system that allows rapid firing of sanitary materials. The low thermal inertia represented by the prefabricated modular structure, obtained with the use of light refractory bricks in the first face and ceramic fibers in the second, represents a necessary condition to give elasticity and manageability to the thermal machine.

For the hypothesised conditions to be realized, however, the plant installed on the machine and the control and regulation devices have been designed in a manner consistent with the required elasticity and manageability. Made these conditions the
the choice between a roller kiln and a fork-lift kiln will be based essentially on the production potential required, on the variety of the planned type or, more generally, on the approach to be made to the production line to be produced, which is the main object of discussion. It should always be remembered that as the dough and the enamel are to be designed according to the thermal cycle that is to be realized, so too the oven to be used must be designed according to the entire production line. Intensive high speed burners are installed on the ovens. The burner types are selected and alternated according to the thermotechnical characteristics of the various zones and the particular functions that are assigned to them in the operating economy of the kiln. Each burner is equipped with automatic ignition and flame control. The rolls are moved by means of a gear transmission.

Each roller is supported on both ends by bearings rotating on bearings. The rotational component is transmitted from the drive shaft to the roller by means of a spring-loaded coupling. The kinematic principle that characterizes the movement is of the bevel gear type with differentiated speed. The gears are made of sintered material. Therefore no lubrication is required. Each oven module has a corresponding movement section driven by a reduction unit and the various groups are connected by means of transmission shafts. At the ends of the gearboxes – trees, two motovariators drive the whole system.

The tunnel kiln we manufacture requires the use of high-speed burners that allow for temperature uniformity, which is also optimal in ovens with very large sections (up to 3,150 mm). In addition, a high efficiency of the heat exchange is obtained and consequently a good level of gas consumption. The preheating zone is served by self-regulating burners which allow to vary the heating curve of the material as desired; this possibility is extremely important in the production of sanitaryware, as often there are variations in load (in weight and volume) that make necessary adjustments to the
cooking curve. Also the cooling of the oven is studied in order to suitably modulate the speed of temperature reduction; the purpose is to ensure easy adjustment of the cooling curve to the various types of material being cooked.

The entire oven is governed by an automatic management system that, through the use of a PC, allows the absolute control of all the functional parameters of the cooking. Particular care has been taken in the design and study of the thermal insulation of the oven so as to reduce the consumption of energy to a minimum and guarantee the maximum durability of the cooking machines. In modern trolleys for fast firing, particular attention must be paid to the design of the loading trolley, whose validity is to be considered fundamental for the operation of the oven.

The concept of the trolley was based on the principle of transferring a metal plane to a controlled planarity outside the furnace in a plane made of refractory material inside the oven. In the transfer the basic flatness must be maintained and the thermal insulation necessary from a structural and functional point of view must be obtained. The solution consists of a series of refractory columns fitted to the base of the support foot and to the top of the supporting column which transfer the required plane, while a filling in ceramic fibers, without any supporting function, guarantees the necessary thermal insulation.

IPEG can supply any type of intermittent oven, from a few m3 up to over 100 m3, always guaranteeing maximum homogeneity in temperature distribution, energy saving and quality of the finished product. IPEG intermittent furnaces use the most modern and most efficient combustion plants, and all are equipped with high-speed burners. The insulation of the ovens is very accurate and provides different options such as the use of ceramic fiber or cordierite sheets.
Particular attention is given to the management and control system that allows all the operating data of the oven to be activated and to intervene to make any changes to the cooking curve.

In order to optimize the operation of the oven, the inverted flue gas extraction system is adopted. The ovens can be made in a single-layer, double-floor and three-storey version, depending on the different needs of the customer. The movement of the trolleys and the system can be equipped with a platform to facilitate the loading and unloading operations of the trolleys.