Field of engineering

The subject of the invention is a device from the field of regulation and automatic regulation of primary, secondary and tertiary air intake to ensure the optimal conditions of combustion and from the field of regulation and/ or control of combustion.

Technical issue

The technical issue resolved by this invention is the design concept of a device that enables the regulation of flue gas flow to increase the efficiency of biomass furnaces by ensuring optimal combustion conditions. Burning in a biomass furnace or stove takes place in three phases. The start-up phase where, due to the cooled flue system, the naturally occurring pressure in the combustion chamber is low and a motorized ventilation system (power-assisted system) is required to achieve a quick start-up without flue gas escaping back into the room. The burning process is when the flue system is warmed up and the natural pressure created accelerates the burning process to a level where the flue gases can reach a temperature of over 600°C and can damage the furnace and flue system. In addition to this, during this phase, a lot of energy which cannot be transferred to the heating system so quickly, goes through the flue system into the environment and has the effect of warming the atmosphere and reducing the efficiency of the heating system itself. The afterburning phase, when the burning fuel requires a mini- mum amount of air to satisfactorily maintain the heat of the furnace and the flue system must be kept almost completely shut in order to extend the afterburning phase and also prevent the escape of warm air from the room through the flue system into the surrounding environment.

Already established status of technology

On the market there are systems that increase draught and are usually installed at the top of the chimney outside the building, which makes installation and maintenance more difficult. On the market are also systems that reduce the speed of the flue gases in the form of flaps on the flue that make the intersection of the chimney narrower. If this type of constraint is not kept under control, it can form soot, as due to the too low temperature in the combustion chamber and the collection of soot in the flue, it can create a fire hazard.

According to EP 2085694 there is a solution called an "Electronically controlled wood-burning stove" that describes the procedure of electronically controlled combustion in the combustion chamber of a furnace, which uses the help of one or more flaps, each powered by an electric motor, and which remain in contact with the air ducts for supplying primary and secondary combustion air. In this solution, the ducts are arranged side by side along the rear side of the wood- burning stove.

According to WO201306815 there is a procedure to accelerate combustion in wood-burning heating devices that has at least a primary, secondary and tertiary air supply, whereby there is a combustion control with which it is possible to set the conditions for various combustion situations. Both aforementioned solutions have a different layout concept for the regulation flap than the solution of this invention.

There is a Slovenian patent, patent No. 24147, in which is described the proce- dure for automatically regulating the optimal conditions for biomass combustion, which, according to the algorithm entered, appropriately assesses the data from the flue gases temperature sensor and the draught sensor, and, with the help of a processor and user interface, sends commands to the electronic control for the fan and the electronic control of the mechanical actuator for moving the flap. This creates the conditions for a quick cold start by taking into consideration the various factors affecting burning, which enables the working temperature to be maintained by constricting the flow of the flue gases, and enables an autonomous means of loading the regulation and control system. The design solution of the device according to the invention is a modular design, whereby the casing con- tains a brake flap in a specific shape, electronic circuitry for the controls, a controlling electronic regulator, two flue gas status sensors, mechatronic actuators and a power unit with a safety function where a flap opens in the event of a power failure and is controlled by a computer-based intelligent system. The system is built into the exhaust pipe and not into the combustion chamber, as is in this invention. Description of the solution to a technical problem

The essence of the invention is the design structure of the device that regulates and optimizes combustion in solid-fuel heating devices that includes a control unit with a preprogrammed algorithm that, on the basis of received commands triggered by the power being switched on with a switch, remote control, smartphone or smart tablet, received data from the flue gases sensor, sensor for residual oxygen in the flue gases and a negative pressure sensor, opens or closes the system of three regulation flaps.

Negative pressure sensor means in this regard an under-pressure sensor.

The invention, a device to regulate and optimize combustion in solid-fuel heating devices, will be described in more detail with the help of images that indicate the following:

Figure 1 device housing,

Figure 2 device housing,

Figure 3 device interior,

Figure 4 block diagram of the device,

The device to regulate and optimize combustion in solid-fuel heating devices has regulation flaps, sensors, a user interface, a customization module and various combustion phases. Regulation of the air flow to the individual parts of the combustion chamber by using flaps enables the regulation of the supply of air to the fuel and wood gas. The air can be supplied to various parts of the combustion chamber in the form of primary, secondary and tertiary air. It is not necessary for all three air flows to be constantly present. Depending on the combustion cham- ber temperature, the combustion chamber temperature sensor, with the purpose of regulating combustion, enables the combustion chamber to change from one combustion phase to another, and controls the air flaps in order to achieve the desired level of efficiency and emissions, as well as carries out safety functions to prevent overheating. Depending on the oxygen content in the flue gases, the oxy- gen sensor in the flue gases, with the purpose of regulating combustion, enables the combustion chamber to change from one combustion phase to another, and controls the air flaps in order to achieve the desired level of efficiency and emissions. The built-in interface that the user uses to control the heating device and start the device, adjusts the power and turns off the heating device. The aforementioned interface is also used to adjust the power of the heating device during the process of combustion. The heating device uses the user interface to communicate the status of the device. The remote control is used by the user to turn the device on/ off and adjust the power, while also communicating the combustion phase and warning when more fuel needs to be added.

The device in the invention includes a negative pressure sensor (under-pressure sensor) with the purpose of regulating the air valves and performing the safety functions. On the basis of the negative pressure detected, the device's control unit enables the control of the air flaps during the various phases of combustion to achieve the desired air flow and performs the safety function of preventing the escape of flue gases into the room.

The mobile app installed on a smart device such as a smartphone or smart tablet allows the user to turn the heating device on and off, adjust the power, communicate the combustion phase and notify you when more fuel needs to be added. At the same time, the mobile app also displays statistical data about the combustion process. The device has modularly designed parts that enable them to be attached to various shaped heating devices. "Modularly" means in this regard not only that the mechanical parts are of modular nature, but also that the whole system is modular. Whereby it is possible to adapt the shape and number of air flaps. The device has the option of being connected to the incoming air flow with the purpose of adapting it to the heating device and the installation location. In view of the modularity of the combustion phases, it is possible to adapt to the type, size and design of the heating device, combustion chamber and type of combustion regulation. The device according to the invention has four openings ( 1 1 ) on the attachment panel ( 1 ) to attach the device onto the bottom part of the combustion chamber of the solid-fuel heating device. The panel ( 1 ) covers the housing (3), which has a tube (2) on the front side (31 ) for air to enter the combustion chamber. The tube (2) can be open and pump air from the heating device's surrounding environment or be connected to the tube that supplies fresh air from outside. On the panel ( 1 ) are three tubes (41 , 51 and 61 ), which are the outlets of the regulation flaps (4, 5 and 6) with actuators. The tubes (41 , 51 and 61 ) are arranged side by side. In the various versions of the devices, the tubes (41 , 51 and 61 ) can be arranged along the axis of the flaps (4, 5 and 6) in various positions in order to adapt to the shape of the heating device. On the side (31 ), there is a socket (7) for connecting the device to the power supply. Cable glands (8) are foreseen on the upper side (32) of the housing (3) for charging the control panel, sensors and flaps. The tubes (41 , 51 and 61 ) are installed directly on the combustion chamber of the heating device.

As the block diagram in Figure 4 illustrates, the device has a control unit (CU), which is connected to the switch (S), remote control (R), smart device (SD) and display (D) through the inputs ( 1 1 , 12, 13 and 14). The smart device (SD) can be a smartphone or smart tablet that has a Bluetooth Smart connection. The control unit (CU) receives signals from the flue gases sensor (SI ), the sensor for residual oxygen in the flue gases (S2) and a negative pressure sensor (S3) (under-pressure sensor) through the inputs ( 15, 16 and 17). The control unit (CU) sends commands through outputs ( 18, 19 and 20) to the flaps (4, 5 and 6) to open and close these flaps. Signals are sent from the control unit (CU) through the output (21 ) to the multifunctional unit (MU), which can be a control arm. The flue gases sensor (S I ) measures the temperature of the flue gases, the sensor for residual oxygen in the flue gases (S2) is a lambda sensor and the negative pressure sensor (S3) is a draught sensor. The flue gases temperature sensor (S I ) measures the temperature on the basis of which it regulates one of three output flaps (4, 5 and 6) and also enables supervision over the heating device's safety. Using the flue gases sensor (SI ), errors can be registered in the event that the heating device is overheating or malfunctioning. It can also regulate the power of the heating device on the basis of the status of the flue gases. Residual oxygen in the flue gases is measured by the sensor (S2), which enables the regulation of the flue gases oxygen content which facilitates the reduction of flue gases emissions into the environment.

The negative pressure sensor (S3) affects the operating of the heating device and/ or the safety of the user. If it detects a low draught due to weather condi- tions, the sensor (S3) can regulate the flaps to enable a more optimal combustion. Furthermore, sensor (S3) detects if the door of the combustion chamber is open, if the flue ducts are blocked and other possible deviations from the optimal conditions for biomass combustion in the combustion chamber. Data from the sensors (SI , S2 and S3) are vital for the control and operation of the output flaps (4, 5 and 6) and the multifunctional unit (MU). The multifunctional unit (MU) can be a flap, an audio and/or visual signal. The appliance in the invention has three flaps (4, 5 and 6) that are open in various phases depending on the temperature of the flue gases, the oxygen content in the flue gases, or the pressure in the combustion chamber. The combustion process has up to 10 phases, where the openness of the flap is determined for each phase using the control unit (CU) and its algorithm depending on the selected parameters. The control unit (CU) can detect the openness of the flap for the secondary and tertiary air, depending on the openness of the primary air and the temperature of the flue gases. The control unit (CU) sends commands to the actuators that move the flaps (4, 5 and 6) into the desired positions

The device enables several modes of control, i.e. automatic start-up recognition, remote control using the remote control (R) or smart device (SD) or manually using the switch (S), where the combustion power can be selected by pressing it several times. Pressing it longer allows the user to choose from additional settings like on/ off, automatic recognition of start up or lack of fuel, or other options.