The object of the invention is a bio-fireplace and a method for refuelling the bio fireplace, quenching the firebox of the bio-fireplace, as well as controlling the combustion of fuel in the firebox of the bio-fireplace.

There are commonly known bio-fireplaces having a firebox for the combustion of liquid fuel. In known solutions, liquid fuel is poured directly into the firebox, or it is stored in a tank, from which it is pumped into the firebox during the use of the bio-fireplace. Manual pouring of liquid fuel directly into the firebox entails the risk of its spilling, as well as improper filling of the firebox, i.e. filling the firebox with an amount which is insufficient or too large. In known solutions utilising a tank with liquid fuel, a peristaltic pump or a fuel pump is in turn used commonly in order to deliver it to the firebox. Such solutions are cumbersome in terms of adjusting the delivery of fuel, and also highly unsustainable - because they require regular replacing of the worn internal pressure hose of the peristaltic pump. Due to their direct contact with fuel, fuel pumps are in turn characterised by their shorter longevity, but also relatively high demand for electricity and limited efficiency adjustment capabilities. Therefore, these solutions are rather inefficient and expensive to maintain.

From Polish patent description PAT.221451 entitled “A method and device for the combustion of liquid fuel, in particular in bio-fireplaces” there is a known solution involving the delivery of fuel by means of a self-priming and self-locking fuel pump, also described as peristaltic, installed on the fuel line. This solution is expensive to maintain due to its use of an internal hose of a peristaltic pump, which requires frequent replacements.

From Polish patent description PAT.232059 entitled “A method and assembly for filling and emptying a fuel tank, in particular the fuel tank of a bio-fireplace” there is a known solution involving the use of two fuel pumps, one of which is a manual pump, the second one being an electric pump. The manual pump is used to suck a small amount of liquid fuel into the circuit of the electric pump, triggering its further operation.

In solutions used to date, liquid fuel was pumped by means of a fuel pump having a low precision, or they had no fuel dispensing systems at all. In the case of solutions with an automatic fuel dispensing system, the pumps used are imprecise, loud and expensive to operate. Moreover, in the solutions used, when the bio-fireplace is no longer in use, the liquid fuel present in the firebox remains inside it until its evaporation. Not only is such a solution rather uneconomical due to fuel losses, but also dangerous due to the possibility of spontaneous ignition of fuel remaining in the firebox, and harmful due to fuel vapours released into the room.

The purpose of the invention is to provide a solution allowing safe and efficient refuelling of a bio-fireplace, to provide control over the combustion of fuel in the firebox of a bio -fireplace, with the use of durable and inexpensive elements, as well as to provide safety and savings of fuel after the end of its combustion in the bio -fireplace.

The bio-fireplace provided with a control system, a system for refuelling an internal tank from an external source, as well as a firebox provided with a protective net, a spigot socket of an outer refuelling line and an ignition element, is characterised in that the internal fuel tank is connected via air lines to at least one air pump and via a fuel line to the firebox, and at the same time it is provided with two solenoid valves. A characteristic feature of the bio-fireplace according to the invention involves the use of a negative air pressure generated by the air pump in the fuel tank in order to force the circulation of fuel when refuelling the internal tank and quenching the firebox, as well as controlling the combustion of fuel in the firebox of the bio fireplace with the use of a fuel level sensor and a positive pressure in the fuel tank. Wherein, in the case of generating a negative pressure, the air pump operates as a vacuum pump. During the combustion of fuel in the firebox of the bio-fireplace, one of the solenoid valves remains closed, with the second one open, and the positive pressure in the tank, controlled by means of the fuel level sensor and the control system, ensures a constant flame size set by the user. When refuelling the internal fuel tank from an external source, one of the solenoid valves in turn remains open, enabling the suction of fuel via the fuel line into the internal tank; the second solenoid valve remains closed, sealing the internal fuel tank. When the bio-fireplace is not in use, both solenoid valves preferably remain closed, sealing the internal fuel tank, ensuring safety and limiting fuel losses caused by its uncontrolled evaporation.

The method for refuelling is characterised in that the transmission of fuel from an external source to the internal tank uses negative pressure generated by the air pump. During the operation of the air pump, one of the solenoid valves is open, enabling the suction of air from the internal tank, while the second solenoid valve remains closed. Negative pressure generated in this manner causes the suction of fuel and its transmission from an external source. Wherein the external fuel source connects to the internal tank via the external and internal fuel line. Upon filling the internal tank to a desired level, or upon prior emptying of the external source, the control system deactivates the pump, stopping the refuelling process. Negative pressure in the internal fuel tank is also used to quench the firebox of the bio-fireplace. In such a case, the external fuel line is not connected, which causes the suction of fuel from the firebox until its complete emptying.

Flame height in the firebox of the device is set by the user, in particular by means of a keyboard on the front panel of the device. In order to provide control over the combustion of fuel, i.e. maintain a constant flame height according to parameters set by the user, the control system controls the level of fuel in the internal tank using the fuel level sensor, at the same time properly adjusting positive pressure generated by the air pump in the tank. Due to this, the increase in air pressure will compensate the drop in the level of fuel, preventing changes in flame height in the firebox.

The solution according to the invention ensures maintaining a constant flame height set by the user, increases the safety and comfort of using the bio -fireplace; it also lowers the operating costs, reduces the emission of harmful fuel vapours into the room and it reduces fuel losses when the bio-fireplace is not in use.

The solution according to the invention is presented in embodiments and in the drawing, in which Fig. 1 includes a general layout of a bio-fireplace with a firebox, a control system, a refuelling system, an internal fuel tank, as well as two air pumps and two solenoid valves, Fig. 2 presents a general layout of the bio-fireplace, with the use of a single air pump and two three- way solenoid valves, Fig. 3 presents a general layout of controlling the combustion of fuel (the black arrow indicates the flow direction of fuel into the firebox; white arrows indicate the air flow direction), Fig. 4 presents a general layout of the generation of negative pressure during refuelling and quenching the bio-fireplace (the black arrow indicates the flow direction of fuel into the internal tank; white arrows indicate the air flow direction), while Fig. 5 presents a general layout of the elements of the bio-fireplace after quenching the firebox (a preferable inactive state of the bio-fireplace).

The symbols in the drawing refer to the following elements: 1 - air pump, 2 - second air pump, 3 - first solenoid valve, 4 - second solenoid valve, 5 - internal fuel tank, 6 - first air line, 7 - second air line, 8 - internal fuel line, 9 - control system, 10 - firebox, 11 - ignition element, 12 - external fuel line, 13 - external fuel tank, 14 - first three-way solenoid valve, 15 - second three-way solenoid valve, 16 - fuel level sensor, 17 - control keyboard. Embodiment 1

When refuelling the bio-fireplace, the spigot of the external fuel line 12 is placed in a socket in the firebox 10, the first solenoid valve 3 remains closed, the air pump 1 is not operating, the second solenoid valve 4 is open, the second air pump 2 sucks the air out of the internal fuel tank 5 generating a negative pressure therein, which causes the suction of fuel via the internal fuel line 8 and the external fuel line 12 from the external fuel source 13. After reaching a proper level of fuel in the internal fuel tank 5, or after prior emptying of the external fuel tank 13, the control system 9 deactivates the second air pump 2 and preferably closes the second solenoid valve 4. After activating the bio-fireplace, the control system 9 controls the level of fuel, analysing readings from the fuel level sensor 16 placed in the internal tank. In the case of a drop in the level of fuel in the internal tank, the control system 9 by means of the air pump 1 increases the air pressure in the internal fuel tank correspondingly, in order to maintain the flame height at a constant level, set by the user via the control keyboard 17. Quenching the firebox of the bio-fireplace proceeds via stopping the operation of the air pump 1, closing the first solenoid valve 3, activating the second air pump 2, which, with the second solenoid valve 4 open, sucks the air out of the internal fuel tank 5, generating negative pressure therein, causing the suction of fuel via the internal fuel line 8 from the firebox 10. After emptying the firebox 10, the control system 9 deactivates the second air pump 2, at the same time preferably closing the second solenoid valve 4.

Embodiment 2

When refuelling the bio-fireplace, the spigot of the external fuel line 12 is placed in a socket in the firebox 10, the first three-way solenoid valve 14 is open in position B-C, the second three-way solenoid valve 15 is open in position A-B, the air pump 1 is operating, sucking the air out of the internal tank 5, generating a negative pressure therein, which causes the suction of fuel via the internal fuel line 8 and the external fuel line 12 from the external fuel source 13. After reaching a proper level of fuel in the internal fuel tank 5, or after prior emptying of the external fuel tank 13, the control system 9 deactivates the air pump 1 and preferably opens the first solenoid valve 14 in position A-B. After activation of the bio-fireplace, the first solenoid valve 14 is set in position A-B, the second solenoid valve 15 is set in position B-C, the air pump 1 is operating, the control system 9 is controlling the level of fuel, analysing the readings of the fuel level sensor 16 placed in the internal tank. In the case of a drop in the level of fuel in the internal tank, the control system 9 by means of the air pump 1 increases the air pressure in the internal fuel tank correspondingly, in order to maintain the flame height at a constant level, set by the user via the control keyboard 17. Quenching the firebox of the bio-fireplace proceeds by opening the first solenoid valve 14 in position B-C; the second three-way solenoid valve 15 is open in position A-B, the air pump 1 sucks the air out of the internal tank 5, generating a negative pressure therein, which causes the suction of fuel via the internal fuel line 8 from the firebox 10 into the internal fuel tank 5. After emptying the firebox 10, the control system 9 deactivates the second air pump 1, at the same time preferably opening the first three-way solenoid valve 14 in position A-B.