HEATING APPLIANCE, METHOD FOR EQUIPPING A HEATING APPLIANCE WITH A CHECK VALVE, AND USE OF A CHECK VALVE AND A CONTROL CABLE

Description

[0001] The invention relates to a heating device, a method for equipping a heating device with a check valve and a use of a check valve.

[0002] In multi-unit buildings with several heating appliances, such as apartment buildings, a check valve is often required to prevent exhaust gases from flowing back from one appliance to another. The check valve allows only unidirectional flow, thus preventing exhaust gases from entering the heating appliance and its surroundings. This is particularly important for the safety of residents when heating appliances are located in living spaces, such as wall-mounted units.

[0003] Check valves are often installed in the exhaust gas path of the heating appliance. However, this exposes the check valve to the high temperatures of the exhaust gas and / or the influence of condensate contained in the exhaust gas, which can negatively affect the service life of the check valve.

[0004] German patent application DE 20 2018 101 271 U1 proposes a heating appliance in which a check valve is arranged between a conveying device and a combustion chamber. However, retrofitting the check valve at this position is problematic, as there are significant requirements for tightness in a fuel gas-carrying line.

[0005] German patent DE 10 2009 030 058 B3 discloses an arrangement of a check valve in a heating unit of a blower, which is positioned upstream in the direction of flow. To achieve a homogeneous flow of combustion air through the check valve, it is proposed that the check valve comprise two check flaps. While this arrangement can also prevent the check valve from being exposed to exhaust gas, it requires, particularly in heating units with a pneumatic gas-air system, an adjustment of the gas valve to compensate for the pressure drop caused by the check valve. This adjustment of the gas valve is difficult for a person skilled in the art to perform at the installation site and entails a considerable risk of error.

[0006] DE 19 22 650 A1 concerns a heating device for liquids which cannot contribute to solving the aforementioned problems.

[0007] The KR 2010 0086650 A concerns a supply device for gas mixtures, for example for a welding machine, and cannot contribute to solving the aforementioned problems.

[0008] The fuel supply system for a vibrating burner shown in DE 975 546 C also cannot solve the aforementioned problems regarding a non-return valve of a heating appliance in a multi-flue exhaust system. The same applies to the adaptive vibration damper for a combustion system presented in EP 3 173 689 A1.

[0009] Based on this, the object of the invention is to propose a heating device, a method for equipping a heating device with a check valve, and an application that at least partially overcome the problems of the prior art described above. In particular, a simple method for equipping a heating device with a check valve, which can be carried out at the installation site, is to be provided.

[0010] These problems are solved by the features of the independent claims. Further advantageous embodiments of the solution proposed here are specified in the independent claims. It should be noted that the features listed in the dependent claims can be combined with one another in any technologically meaningful way and define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, which also presents further preferred embodiments of the invention.

[0011] This includes a method for equipping a heating appliance with a non-return valve or for setting up a heating appliance for multiple connections to the exhaust system, comprising at least the following steps: a) Installation of the check valve in an air supply at a position, viewed in a flow direction of the heating appliance, upstream of a venturi device of the heating appliance, b) Connecting a control line of the gas valve to the air supply of the heating appliance between the venturi device and the check valve.

[0012] Steps a) and b) can be performed at least once in the specified or reverse order during normal operation. It is also possible to perform steps a) and b) at least partially simultaneously or in parallel.

[0013] This method is primarily used to integrate a check valve into a heating appliance for connection to a shared exhaust system. The check valve can significantly reduce or even prevent the backflow of exhaust gases (from another heating appliance).

[0014] The heating appliance can be specifically designed for the combustion of fuel gas. This gas can be, for example, natural gas or hydrogen. The heating appliance can draw in combustion air via an air supply using a conveying device, such as a fan. A defined quantity of fuel gas can be added to this air supply via a gas valve and a Venturi device. The combustion mixture of fuel gas and combustion air can then be fed via a mixture channel to a burner, often located in a combustion chamber. At least one heat exchanger can be arranged in the exhaust system of the heating appliance. This heat exchanger transfers the heat generated during combustion to a heat transfer medium that can circulate in a heating circuit. The air supply to the heating appliance can include a silencer that compensates for pressure surges in the conveying device and thus reduces the noise emissions of the heating appliance.The heating appliance can be, in particular, a wall-mounted unit that can be installed in the living space. It may be possible for an exhaust system to be shared by several apartments, for example in multi-family buildings (so-called "multiple occupancy").

[0015] According to the current state of the art, at the start of a combustion process, the supply system is switched on, directing a predefined airflow through a Venturi device (also called a throttle), in particular a Venturi nozzle, into a burner. Fuel gas is mixed into this airflow at a fuel gas inlet, usually upstream of or within the Venturi device. For this purpose, a gas valve (also called a fuel gas control valve) can be opened. To ensure that fuel gas is not mixed in too early when the supply system starts up or in the wrong quantity during operation, a control line (also called a reference pressure line) transmits a reference pressure, which, according to the current state of the art, is taken from the air supply, for example, in the intake silencer, to the gas valve, so that the valve can only open when a sufficient airflow is being supplied by the supply system.The gas valve can be configured to release a quantity of fuel gas proportional to the reference pressure within a certain control range (modulation range) of the heating appliance. Conversely, the gas valve closes if, for any reason, insufficient airflow is supplied through the delivery system because the reference pressure then becomes too low. This type of mixture composition control in a heating appliance is also known as a pneumatic gas-air mixture control.

[0016] A check valve is a valve that allows flow in only one direction. Installed in the gas-air path of a heating appliance, it prevents the backflow of exhaust gas from the (multi-flue) exhaust system. A check valve is also frequently referred to as a non-return valve, and a check valve can also comprise several (parallel) non-return valves.

[0017] According to step a), the check valve can be installed in the air supply of the heating appliance at a position, viewed in the direction of flow through the heating appliance, upstream of a Venturi unit of the heating appliance. Installation can be achieved, for example, by replacing a section of pipe with a section containing a check valve. Advantageously, a check valve in this position is not exposed to high temperatures or condensate (contained in the exhaust gas) compared to an installation in the exhaust gas path. Furthermore, the requirements for gas tightness of the installation are lower when located in a combustion air supply line of the heating appliance than in a fuel gas line, such as the mixture channel downstream of the Venturi unit. The check valve can also be located upstream of the heating appliance's delivery system in the direction of flow.

[0018] According to step b), a control line of the gas valve can be connected to the air supply between the venturi device and the check valve. In other words, the reference pressure of the gas valve can be taken between the venturi device and the check valve. Advantageously, this avoids any influence of the check valve on the reference pressure, and adjustment of the gas valve to the pressure drop caused by the check valve is unnecessary. The method proposed here can therefore be easily implemented during the installation of the heating appliance at its installation site.

[0019] According to a further embodiment, when carrying out step a), the check valve can be installed in a silencer of the heating appliance. The installation can be carried out, in particular, by replacing the silencer with one that includes a check valve.

[0020] A silencer for a heating appliance is a component of the air supply system that can compensate for pressure surges from the conveying device and thus potentially reduce the noise emissions of the heating appliance.

[0021] According to another aspect, a heating device is also proposed, designed for the combustion of a gaseous fuel, comprising a gas valve and a Venturi device, wherein a check valve, seen in a flow direction of the heating device, is arranged upstream of the Venturi device and a control line of the gas valve is connected to a combustion air-carrying line between the Venturi device and the check valve.

[0022] According to one embodiment, the check valve can be arranged in a silencer of the air supply of the heating device.

[0023] The silencer can include a connection for a gas valve control line. This significantly simplifies the subsequent installation of a check valve, requiring only the replacement of the silencer and the connection of the gas valve control line.

[0024] Another aspect is the use of a check valve, seen in a flow direction of a heating device, arranged upstream of a Venturi device and connected to a control line with a combustion air line between the Venturi device and the check valve, to set up the heating device for multiple occupancy of the exhaust system.

[0025] The details, features, and advantageous designs discussed in connection with the process may also apply to the heating device and its use presented here, and vice versa. In this respect, full reference is made to the explanations provided therein for a more detailed characterization of the features.

[0026] This document describes a method for equipping a heating appliance with a non-return valve, a heating appliance, and an application that at least partially solves the problems described with reference to the prior art. In particular, the method, the heating appliance, and the application contribute to proposing a simple and readily implementable method for equipping a heating appliance with a non-return valve.

[0027] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations described in the figures and combine them with other components and findings from the present description. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. They show: Fig. 1 : a heating device suggested here, Fig. 2 : a section of a heating appliance comprising a silencer and a gas valve, and Fig. 3 : Curves of an air ratio λ in the modulation range of a heating device proposed here.

[0028] Fig. 1 Figure 1 shows an exemplary and schematic representation of a proposed heating device 1. This device can have an air supply 4 for combustion air. A fuel gas supply 8 can have a gas valve 5. A Venturi device 15 can be arranged in the air supply 4, which adds a quantity of gas corresponding to a control pressure generated by the mass flow of combustion air. The control pressure can be transmitted to the gas valve 5 via a control line 18, which can be connected to the air supply 4 in a region between the check valve 17 and the Venturi device 15. A gas valve 5 can also be arranged in the fuel gas supply 8.

[0029] Viewed in a flow direction 19 of the heating appliance 1, a conveying device 2 can be arranged downstream of the Venturi device 15, which can supply the mixture of fuel gas and combustion air to a burner 3 via a mixture channel 12. A heat exchanger 13 can be arranged at the burner 3, which can transfer the heat generated during combustion to a heat transfer medium circulating in a domestic hot water circuit with a supply line 6 and a return line 9.

[0030] Downstream of the burner 3, an exhaust pipe 10 can feed combustion products to an exhaust system 11. A control and regulating unit 7 of the heating appliance 1 can be electrically connected to at least the gas valve 5 and the blower 2.

[0031] The air supply 4 can include a silencer 16 in which a non-return valve 17 can be arranged.

[0032] Fig. 2 Figure 1 shows an exemplary and schematic representation of a section of a heating appliance 1, comprising the gas valve 5 with a control line 18, which can be connected to a port 23 on the silencer 16. The silencer 16 also contains a check valve 17, which is only open to flow in the direction 19 and thus blocks backflow.

[0033] Fig. 3 Figure 1 shows, by way of example and schematic, the curves of an air-fuel ratio λ in a modulation range of a heating device 1. Curves 19, 20, 21 show the air-fuel ratio λ set by the heating device 1 over a modulation range P of the heating device 1, given in kW [kilowatts].

[0034] A reference curve 20 shows the course of the air-fuel ratio λ for a heating device 1 without a check valve 17. Curve 21 shows the course of the air-fuel ratio λ for a heating device 1 after performing step a). The control line 18 is not connected to the air supply 4 between the venturi device 15 and the check valve 17. A deviation in the air-fuel ratio λ is clearly visible at low heating output of the heating device 1, particularly between 6 kW and 12 kW. This deviation means that the heating device 1 does not operate with an optimal air-fuel ratio λ in this range due to the uncompensated pressure drop of the check valve 17, which, for example, is accompanied by a decrease in the energy efficiency of the heating device 1.

[0035] Curve 22 shows the course of the air ratio λ for a heating device 1 after carrying out a procedure proposed here, i.e. steps a) and b). It is clearly visible that the deviation of curve 21 from the reference curve 20, in which the heating device 1 does not compensate for the pressure drop caused by the check valve 17, can be compensated. Reference symbol list

[0036] 1 Heater 2 Blower 3 Burner 4 Air supply 5 Fuel gas valve 6 Flow 7 Control and regulating unit 8 Housing 9 Return 10 Exhaust pipe 11 Exhaust system 12 Mixing channel 13 Heat exchanger 14 Domestic hot water circuit 15 Venturi device 16 Silencer 17 Check valve 18 Control line 19 Flow direction 20 Reference curve 21 Curve with check valve 22 Curve with check valve and control line 23 Control line connection

Claims

1. Method for equipping a heating appliance (1) with a non-return valve (17) and for setting up the heating appliance (1) for multiple occupancy of an exhaust system (11), comprising at least the following steps: a) Installing the non-return valve (17) in an air supply (4) at a position upstream of a venturi device (15) of the heating appliance (1), viewed in the direction of flow (19) of the heating appliance, b) connecting a control line (18) of the gas valve (5) to the air supply (4) between the venturi device (15) and the non-return valve (17).

2. . Method according to claim 1, wherein in step a) the non-return valve (17) is installed in a silencer (16) of the air supply (4).

3. . Heating appliance (1) designed for the combustion of a gaseous fuel, comprising a non-return valve (17) and a gas valve (5) with a venturi device (15), wherein the non-return valve (17) is arranged in a flow direction (19) of the heating appliance (1) and a control line (18) of the gas valve (5) is connected to an air supply (4) of the heating appliance (1) between the venturi device (15) and the non-return valve (17).

4. . Heating appliance according to claim 3, wherein the non-return valve (17) is arranged in a silencer (16) of the heating appliance (1).

5. . Use of a non-return valve (17) arranged in a flow direction (19) of a heating appliance (1), seen upstream of a venturi device (15), and a control line (18) connected to an air supply (4) of the heating appliance (1) between the venturi device (15) and the non-return valve (17), for setting up the heating appliance (1) for multiple occupancy of the exhaust system (11).