CONSTRUCTIONAL ARRANGEMENT INTRODUCED IN A BIOMASS (PELLET) SOLID FUEL STOVE

Abstract

The utility model refers to a constructive arrangement introduced in a solid biomass (pellet) fuel stove, situated in the technological sector of domestic solid fuel stoves or ovens, specifically to constructive arrangements for the circulation of combustion air inside or around stoves, aiming to optimize and control heat exchange and the thermal utilization of gases in the stove, both for heating the environment and for cooking food. There are several models of stoves that use solid fuel, however, they do not present good utilization of the heat generated by the burner, resulting in low thermal efficiency; as well as lacking a safety device against overheating, which can cause food to burn or excessive temperature in the environment.For this purpose, it comprises a cabinet (1) with controller (6), ceramic glass cooking table (7), oven (3) and combustion chamber (5) with burner (9) and connected to the feeder (11); it has an air inlet (13) next to the microfan (14) with intake (15) with piping (16) to the burner (9) in the chamber (5), which has a passage (17) to the table (7) provided with a passage (18) to the oven (3) equipped with a side passage (19), deflector (20) and followed by an exhaust fan (21) with an opening (22) for the chimney (not shown); it is also equipped with an overheating safety device consisting of a temperature sensor (23) in the oven (3), and a temperature sensor (24) next to the burner (9), connected to a printed circuit board (25) of the controller (6).

Description

- 1 / 10 “CONSTRUCTIVE ARRANGEMENT INTRODUCED IN A BIOMASS (PELLET) SOLID FUEL STOVE” INTRODUCTION

[001] The present utility model refers to an innovative constructive arrangement introduced in a solid biomass (pellet) fuel stove located in the technological sector of domestic solid fuel stoves or cookers, more precisely, constructive arrangements with combustion air or combustion gas circulation inside or around stoves, aiming to optimize and control heat exchange, and the thermal utilization of heat from the gases inside and outside the stove, both for cooking food and for heating the environment; as well as the control of the generated temperature through a safety device that cuts off the supply of pellets to the burner when an excess of heat occurs, by means of monitoring through a set of temperature sensors. STATE OF THE ART

[002] It is known from the state of the art that there are several models of stoves that use solid fuel, mainly pellets, however, one of the inherent characteristics of the equipment of the current state of the art refers to the fact that the gas outlet to the chimney occurs at the top, generating a low pressure that excessively increases the flow of hot air through the interior of the stove, not providing the total transfer of heat generated by the burner, which ends up exiting through the chimney, resulting in low thermal efficiency. This problem is aggravated when a centrifugal fan is adopted, used to pull air to the chimney outlet of the stove, causing the generated heat not to be used to its full potential.

[003] Furthermore, in existing stove models in the state of the art, the path of the hot air first reaches the oven to, Petition 870200099022, dated 07 / 08 / 2020, page 9 / 25 - 2 / 10 later, it reaches the table, on the upper part, causing the oven to receive gases with temperature peaks, which occurs when more wood or pellets are placed in the combustion system, and these temperature peaks end up drastically altering the food processing conditions in the oven, and may even lead to the food burning.

[004] Also characteristic of currently existing stove models is that, due to the chimney outlet being positioned at the top, it ends up interfering with the surface of the cooktop, making it difficult to use a tempered glass cooktop, thus preventing the cooking of food directly on the surface.

[005] Similarly, in currently existing stove models, the positioning of the chimney outlet at the top causes the flow of hot air to occur directly from bottom to top, without traveling along paths that could increase heat exchange, which, added to the fact that many stove models have a fan for air exhaust, ends up causing low pressure inside the equipment, not favoring heat exchange, resulting in lower thermal efficiency.

[006] Finally, in currently existing stove models, if the desired temperature is exceeded, there is no device to control the temperature by controlling the pellet feed, which will continue to be done along with the burner, producing even more heat, which may cause the stove to overheat and burn the food, or the ambient temperature to become excessively high.

[007] From the current state of the art, patent document PI0303647-2, filed on 10 / 14 / 2003 and entitled ECOLOGICAL, EFFICIENT AND SMOKE-FREE WOOD STOVE, can be cited, which describes a stove consisting of a combustion chamber in the form of Petition 870200099022, dated 07 / 08 / 2020, page 10 / 25 - 3 / 10 of 'L' (A) immersed in a thermally insulating environment (C), a cast iron plate (D), a chimney (F), all structured by angle irons (H) and galvanized or anti-corrosive sheets (I). Additionally, this stove may have an oven (E) and a coil system (G) for heating water coupled around the combustion chamber, or on the plate, or even on the external base of the chimney.

[008] Patent document MU8900584-8, filed in The design dated 08 / 04 / 2009 and entitled “ARRANGEMENT IN WOOD-BURNING STOVE” aims to describe a wood-burning stove comprising a firebox (7) facing the front wall (2), consisting of two contiguous and orthogonal chambers, an anterior and horizontal one (71) for wood combustion and a posterior and vertical one (72) for conducting gases to the top plate (1). The combustion chamber (71) has a base (73) in the form of a split trough covered by a semicircular roof (74). The rear chamber (72) has a long rear wall (75) and a short front wall (76), both semicircular, forming a vertical duct. Preferably, the split base (73), the roof (74) and the front wall (76) are molded in ceramic or refractory material, while the rear wall (75) is made of cast iron. Around the upper opening of the duct (72) are arranged deflector plates (8) for the hot gases on the top plate (1) of the stove.The furnace opening (7) has a frame (9) for connection to the front plate (2) of the stove and receives a hinged door (91). An ash drawer (92) slides in the bottom of the furnace base (73). A grate (93) slides in channels of the furnace base (73) and is positioned above the drawer (92). One constructive option for the wood-burning stove features an oven (10) orthogonal to the furnace (7). The side wall (12) of the oven is fixed to the central portion of the rear wall (75) of the furnace. Also optionally, the wood-burning stove may feature a coil (13) in the form of a U-shaped bent tube that starts at the rear wall (4) of the stove and surrounds the opening of the chamber. Petition 870200099022, dated 07 / 08 / 2020, p. 11 / 25 - 4 / 10 upper furnace (72) and returns to the rear wall (4).

[009] Patent document BR 10 2015 025786 4, filed on 09 / 10 / 2015 and entitled “OVEN FOR WOOD STOVE”, describes an oven whose main part (1) is formed by the 4 walls containing the hot air channels (6), which increase the heat transmission area and thus increase the heating speed and fuel economy. The plate corresponding to the back wall (2) is located opposite the access door (3). The inlet and outlet of the channels have the numbers (4) and (5) respectively.

[010] Patent document MU 6501878-8, filed in 20 / 11 / 1985 and entitled “CONSTRUCTIVE DEVICE IN A STOVE THAT USES SAWDUST OR TWIGS AS FUEL”, which describes a constructive arrangement in a stove that uses sawdust or twigs as fuel, consisting of a body (1), having on its upper part a plate (2) and respective burners (3) with lids (4), while in its internal part there is a partition (5), configuring two compartments, one for the oven (8) and the other for the heating chamber (9), the latter formed by a plate (10) and vent, while the other is formed by a box (14) with a door (15) and vent (16), as also said oven (8) communicates with a chimney (9). It can be observed, in the cutaway views of compartment (1), that the heated air exits the burner and passes first through the upper part, next to the plate (2), and then continues and passes through the oven (8), around compartment (14).

[011] Similarly, the concept present in the object of the patent MU 6501878-8 requires a procedure for its operation, namely the use of a wooden cylinder (23) to promote the creation of a ventilation tunnel in the middle of the sawdust (5), which must be tamped down sufficiently to maintain the shape.

[012] This procedure does not preclude the situation in which, as the Petition 870200099022, dated 07 / 08 / 2020, page 12 / 25 - 5 / 10 gas stream is upward, and moves directly to the upper plate, when a sudden increase in combustion occurs, the high temperature gases immediately increase the temperature of the plate (2), and, consequently, of the food being processed, there being a risk of burning it, requiring the user to carefully monitor the entire food preparation process. UTILITY MODEL SOLUTION

[013] The object of the present utility model is an innovative constructive arrangement introduced in a solid biomass (pellet) fuel stove that provides for the blowing of air through the bottom of the stove, promoting the generation of an airflow, from the bottom, towards the top, where the cooking table is positioned.

[014] This configuration has two innovative technical features that optimize the operation of the equipment: a) Regarding the improvement of internal functioning, blowing air from bottom to top, followed by top to bottom, doubles the path of the combustion gases, which enhances the heat transfer to the cooktop of the stove so that it heats up sufficiently to optimize food preparation; as well as following the flow of hot air moving downwards along the inner side of the stove, around the oven, already at a more attenuated and homogeneous temperature, without temperature peaks, in order to maintain more adequate control of the baking process in the oven. b) Regarding the improved external functioning for the environment, the fact that air enters the stove via a micro-fan at the bottom forces the intake of cold ambient air, which then circulates upwards through the interior of the stove to the cooking surface, which also serves as a heating surface for the environment, and descends along the side of the oven, exiting through the chimney located at the bottom, thus releasing heat. Petition 870200099022, dated 07 / 08 / 2020, page 13 / 25 - 6 / 10 in the lower region of the environment, usually with a lower temperature, allowing maximum use of heat for the environment, thus achieving better performance.

[015] The cooking table receiving the initial flow of hot air will act as a thermal buffer, preventing uncontrolled temperature spikes from reaching the oven, which could cause the food to burn during baking; at the same time, the table stores heat for moments when the temperature of the hot air generated by the furnace decreases, helping to maintain the temperature of the hot air to be transferred to the oven, which ensures greater homogeneity and control of food processing.

[016] As already explained, the cooking table receiving the initial flow of hot air also promotes more effective heating of the environment, given that its surface will have the highest temperature generated by the burner, and the largest contact area with the ambient air, providing greater heat transfer, optimizing the equipment's performance as a space heater.

[017] The pellet reservoir positioned next to the stove cabinet promotes the maintenance of low humidity or drying of the solid fuel, in order to guarantee its optimized combustion with the burner; as well as, being equipped with a hopper, it ensures that all the solid fuel (pellet) stored there is used in the process.

[018] The equipment also has an electronic safety device against overheating, using sensors near the oven and burner, which are connected to the controller that cuts off the pellet feed to the burner to reduce combustion, lowering the temperature in the stove, thus preventing the risk of burning food; as well as excessive and unnecessary consumption of solid biomass fuel. Petition 870200099022, dated 07 / 08 / 2020, page 14 / 25 7 / 10 Advantages of the Utility Model

[019] The new constructive arrangement introduced in a solid biomass (pellet) fuel stove, proposed by this utility model, results in the following advantages in relation to the state of the art: it guarantees the flow of hotter air generated by the stove to promote the heating of the environment; it promotes the cooking surface to function as a thermal buffer, preventing temperature peaks from reaching the oven and avoiding the risk of burning the food inside, and at the same time, it stores heat for moments when the temperature of the hot air generated by the burner decreases, when it acts as a temperature maintainer of the hot air, homogenizing the temperature of the airflow to be transferred to the oven; it optimizes the thermal efficiency of the equipment since it takes advantage of the temperature peaks in the upper part, which is intended for cooking food, and for heating the environment;It features a pellet reservoir positioned next to the stove cabinet, which promotes the maintenance of low humidity or drying of the solid fuel, thus ensuring its optimized combustion in the burner; as well as a reservoir equipped with a hopper, allowing all the solid fuel (pellets) stored inside to be used in the process; it also features an electronic safety device against overheating, which prevents the risk of burning food and excessive consumption of biomass solid fuel. DESCRIPTION OF THE UTILITY MODEL

[020] The innovative constructive arrangement introduced in the solid biomass (pellet) fuel stove of the present utility model will now be described in detail based on the attached drawings, listed below: Figure 1 - a perspective view of the constructive arrangement in an idealized pellet stove; Petition 870200099022, dated 07 / 08 / 2020, page 15 / 25 8 / 10 Figure 2 - a left side view referring to figure 01; Figure 3 - a front view referring to figure 01; Figure 4 - a right side view referring to figure 01; Figure 5 - a rear view referring to figure 01; Figure 6 - a rear view referring to figure 05, in a visualization where the set of internal components can be seen; Figure 7 - a perspective view referring to figure 05, also showing the identification of the internal components; Figure 8 - a schematic view of the electrical circuit diagram of the electronic overheating safety device; Figure 9 - a front view, in cross-section, showing the path of combustion gases through the interior of the equipment with the idealized construction arrangement; and, Figure 10 - a rear view, in cross-section, showing the path of the combustion gases through the interior of the equipment with the idealized construction arrangement.

[021] Figures 1 to 10 illustrate the constructive arrangement introduced in an idealized solid biomass (pellet) fuel stove, which comprises a cabinet (1) equipped, on the front, with a door (2) for access to the oven (3), and a door (4) for access to the combustion chamber (5), together with the controller (6); and, on the top, it is equipped with a ceramic glass cooking table (7); and, internally, with the oven (3) and the combustion chamber (5), which is equipped with a micro cooling fan (8) and provided with a burner (9), with a cartridge resistance (10), and is interconnected to Petition 870200099022, dated 07 / 08 / 2020, p. 16 / 25 - 9 / 10 feeder with electric motor (11) and pellet reservoir with hopper (12) in the rear region of the cabinet (1) where, at the bottom, an air inlet (13) is positioned next to the intake microfan (14), which is followed by an air intake (15) continued by the piping (16) that culminates in the burner (9), next to the combustion chamber (5), which has a direct passage (17) for the flow of combustion gases, ascending, to the ceramic glass cooking table (7), where there is a second passage (18) for the said gases to go to the oven (3), which has a side passage (19), said to be the passage of combustion gases, which, by the action of the deflector (20), pass through the lower part of the oven (3) and are sucked by the exhaust fan (21) located in the lower part of the cabinet (1), where there is an opening (22), said to be the chimney coupling (not illustrated).

[022] Figures 5, 6 and 7 show the path of cold air entering the environment and the gases exiting to the chimney (not shown), which begins with the air inlet (13) to the intake microfan (14), followed by the air intake (15), continuing through the pipe (16), culminating in the burner (9) next to the combustion chamber (5).

[023] Figure 8 shows the electrical circuit diagram of the electronic overheating safety device, which controls the pellet feed to the burner (9) by means of a temperature sensor (23) in the oven (3), and a temperature sensor (24) next to the burner (9), which are connected to a printed circuit board (25) of the controller (6) where, if the temperature programmed by the user is reached, the feeder (11) will automatically switch off, thus no longer feeding the burner (9), which results in reduced combustion and lowers the temperature in the stove or heater, preventing the risk of burning. Petition 870200099022, dated 07 / 08 / 2020, page 17 / 25 - 10 / 10 food, or, excess heat in the environment and unnecessary pellet consumption.

[024] Figure 9 presents a front perspective view, in cross section, where the cabinet (1) equipped with the ceramic glass cooking table (7) is visualized, inside which the path that the combustion gas flow travels inside the stove is evident, with the combustion chamber (5) equipped with the burner (9) with piping (16), along with the cooling microfan (8); in addition to the path for the rising gases (17) that leads to the cooking table (7) and the oven (3), which has a side passage for the path of the gases (15) being sucked by the exhaust fan (20) that leads them to the opening (21), said to be the chimney coupling (not illustrated).

[025] Figure 10 shows a rear view, in cross section, where the cabinet (1) equipped with the ceramic glass cooking table (7) is visible, inside which the path that the combustion gas flow travels inside the stove is evident, with the combustion chamber (5) equipped with the burner (9) with piping (16), along with the cooling microfan (8); in addition to the path for the rising gases (17) that leads them to the cooking table (7), and a second passage (18) for the said gases to go to the oven (3), which has a side passage (19), called the passage of the combustion gases, which, by the action of the deflector (20), pass through the interior of the oven (3) and are sucked by the exhaust fan (21) located in the lower part of the cabinet (1), to exit through the opening (21), called the chimney coupling (not illustrated). Petition 870200099022, dated 07 / 08 / 2020, page 18 / 25

Claims

- 1 / 1 CLAIM 1 - “CONSTRUCTIVE ARRANGEMENT INTRODUCED IN SOLID BIOMASS (PELLET) FUEL STOVE” comprising a cabinet (1) equipped, on the front, with a door (2) for access to the oven (3), a door (4) for access to the combustion chamber (5), in addition to the controller (6);wherein, in the upper part, there is a cooking table (7), characterized by having the cooking table (7) made of ceramic glass and, internally, the combustion chamber (5) equipped with a cooling microfan (8) and provided with a burner (9), with cartridge resistance (10), and is interconnected to the feeder (11) with pellet reservoir with hopper (12) in the rear region of the cabinet (1), where, in the lower part, an air inlet (13) is positioned, next to the intake microfan (14), which is followed by an air intake (15) continued by the piping (16) that culminates in the burner (9), next to the combustion chamber (5), which has a direct passage (17) to the cooking table (7), where there is a second passage (18) to the oven (3), which has a side passage (19) to the deflector (20), just below and in communication with the oven (3);wherein, in the lower part of the cabinet (1), there is an exhaust fan (21) connected to an opening (22), called the chimney coupling (not shown); it is also equipped with an electronic safety device against overheating, by means of a temperature sensor (23) in the oven (3), and a temperature sensor (24) next to the burner (9), which are connected to a printed circuit board (25) of the controller (6).; Petition 870200099022, dated 07 / 08 / 2020, page 19 / 25

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