The subject of the utility model is a device for supplying air and fuel to a pellet burner, being one of the parts of the burner, designed for burning any ecological renewable fuel of any form - supplied in a form of bulk materials, delivered in a form of granulated product, milling or powders (for example, pellets made of strew, waste wood such as sawdust, wood shavings, chips, bark, and agropellets - made of stones, husk, cereal, stems and hay of green biomass). This device performs two functions - it delivers air into a blow-in chamber of the burner and it also transmits power to a worm feeder delivering fuel to the burner's combustion chamber.

There are centrifugal fans commonly known, a task of which is forcing through a great amount of pressurised air, scattered by blades of a rotor, and directed to the outlet. They can be used in a variety of applications, the ones for heating, ventilating and air-conditioning systems including.

There is known a fan described in the Polish utility model Ru. 061624 (Yl) as the one designed especially for fireplaces, shown in an exemplary embodiment in the drawing Pos. I., improving a process of effective distribution of heat produced in the fireplace hearth. The device consists of a housing, a motor and blades of a fan and it is characterised in that the motor (2) is situated inside the housing (1) and is permanently connected with it throughout its axis (3), in addition, the motor (2) is made of materials resistant to high temperatures, whereas the fan's blades (5) are set on a rotating stator (2) of the motor. The air heated up during a combustion process is sucked in throughout an inlet hole (4) to the inside of the fan housing ( 1). Next, it is abruptly pushed out throughout an outlet hole (6) by means of blades (5) set on the rotating stator of the motor (2), and directed to a duct distributing warm air to the other rooms. Moreover, the fan can be equipped with a control and safety system (7), which adjusts revolutions of the motor to parameters of air flowing throughout the distribution duct.

The ecological boilers and burners of different types, designed for burning pellets, based on different design solutions are well known and are becoming more and more popular, however, in each case they are equipped with a burner body with a combustion chamber, a worm feeder dosing biomass delivered in a form of pellets, an inlet hole for pellets, and a fan delivering air for burning and, alternatively, the other systems of aeration in a form of nozzles, for example. These devices take in fuel from containers throughout special feeders adapted for transporting pellets and delivering them to the combustion chamber of the burner. There are three different systems of delivering pellets: i.e. the mechanical, gravitational, and pneumatic ones. A mutual combination of these different ways of delivering is often used. All known feeders are comprised of a body equipped with a drive, a rigid or, in option, a flexible transportation pipe, which can be slightly bent in all directions and is provided with a steel worm spiral operating inside this pipe. Owing to such systems it is possible to supply the pellet burner with a fuel delivered from distant storage places, for example, in situations when pellets or biomass are stored in a central container situated at the same site as the boiler-room however, in a certain distance from the stove, or they are located inside the same building but in a completely different storeroom made of metal or other materials, or in a large, underground fuel tank, or in any container, barrel, a box etc. for example, or pellets can be stored in a grain silo, for instance, situated outside in a remote even to 60 m from the stove.

There are known some retort pellets burners, offered by the various manufacturers, to which fuel is supplied from an outer tank using a feeder provided in a form of a flexible pipe. Pellets are poured throughout a controlled lock into an inner store container located at the very burner. The maximum filling level is set by a state sensor. Further transportation of pellets - already within the burner - is performed using a spiral, worm feeder, and the fuel is delivered to the burner from its bottom side. The pellets are transported to the rotary combustion chamber, the so-called retort, situated above the feeder, and they are completely burnt in it. The rotation of the retort helps to move ash away and improves the burning conditions. Falling out of the unburned pellets of the combustion chamber is not possible. Only light ash can be blown out of the retort. In this type of burners there is a triple aeration system. First of all the air is delivered by a fan located in the burner providing the hot air flow, thanks to which pellets can be automatically ignited in the retort. This hot air flow coming from the fan is not used for transporting pellets. In addition, the burner is equipped with a secondary air blow-in, just above the hearth. The secondary air is delivered, throughout the throttles properly shaped and ended with nozzles, directly over the retort, burning out the formed gases. A precise, spatial and multi-point air dosing enables the high efficiency combustion to be obtained, limiting the amount of ash as well. In turn, the primary air is being blown in into ducts provided in the retort's floor.

Furthermore, the burner is equipped with a special ring which is to fulfil two tasks - to remove ash from the hearth and to move a grate so as to get an uniform distribution of glow over the entire hearth {of the burner). The device for supplying air and fuel to a pellet burner, according to the utility model, is comprised of a centrifugal fan, the motor of which is located inside a blade ring of the fan's rotor. In accordance with the utility model the fan is equipped with a shaft with a notched rack, which meshes with a transmission mechanism, and the transmission is aligned with the fan by means of a centring sleeve. On the other side there is a fuel feeder attached to the transmission shaft, made in a form of a steel worm spring, ended with an additional mixing element.

Owing to the solution according to the utility model, a simple design solution of the device has been developed, in which its two basic functions are combined, i.e. a traditional function of delivering air to the blowing-in chamber of the pellets burner, and the one transmitting drive to the feeder delivering the pellets fuel into the burner combustion chamber are being performed.

The subject of the utility model is shown in the drawing, Fig. 1 , of which shows an exploded perspective view from the top of the device delivering fuel and air to the pellet burner; Fig 2 shows as side view of the device; and Fig. 3 - shows a side view of the centrifugal fan.

The device presented in the drawing is one of the elements of the pellet burner and it is comprised of a centrifugal fan 1, having a rotor 2 with a blade-ring 3 and it is equipped with a shaft 4 with a notched rack, in addition, the shaft 4, while passing throughout a mounting plate 5, meshes with a transmission mechanism 6. The transmission 6 is aligned with the fan by means of the centring sleeve 7, whereas, on the other side there is a feeder 10, which is attached using a press bolt 9 to the shaft 8 of the transmission 6, and it is formed in a steel worm spiral for transporting pellets and delivering fuel to the burner combustion chamber. The feeder 10 is ended with an additional, triangular, mixing element 11.

List of designations(labels) - fan

- rotor

- blade-ring

- fan's shaft

- mounting plate

- transmission (gear)

- centring sleeve

- transmission's (gear's) (shaft

- press bolt

- fedder (conveyor)

- mixing element