Gas control valve for electronic pressure control on a gas boiler

Description

[0001] The invention relates to a gas control valve, such as is used in particular for electronic pressure control in gas boilers.

[0002] Gas control valves for pressure regulation are known in the prior art and, for example, from document DE 10 2018 102 866 A1. In gas boilers in which a gas-air mixture is burned, a gas control valve is used upstream of a mixing device, in which gas is mixed with air to form the gas-air mixture, and further upstream of a main flow restrictor, to adjust or regulate the gas volume flow into the mixing device.

[0003] Furthermore, the state of the art usually provides that the pressure control is implemented by a single sensor, and in particular a single, especially electrical, differential pressure sensor, which determines the pressure difference or differential pressure between the pressure of the gas at a first measuring point between the gas control valve and the main flow throttle and the pressure of the air at a second measuring point, which flows into the mixing device.

[0004] In addition to general pressure control, electronic zero-pressure control is also known in the prior art. Typically, the gas control valve regulates or sets the gas flow rate into the mixing device in such a way that the pressure difference is zero, hence the term zero-pressure control.

[0005] The problem is that such differential pressure sensors or other alternative sensors for determining the flow rate of the gas through the gas control valve and thus the pressure difference between gas and air must each be calibrated, and the entire control system depends on the determined value.

[0006] In addition, such sensors are usually connected to the respective measuring points via comparatively long pressure lines, which leads to additional sources of error and a time-consuming and therefore expensive installation.

[0007] Further relevant prior art in this field is also provided by US 2013 / 153041 A1, EP 1 843 095 A2, DE 198 24 521 A1 and US 2018 / 058691 A1. US 2013 / 0153041 A1 discloses a gas control valve for the electronic pressure control of a gas-air mixture in a gas boiler. The gas control valve comprises a central module, a control module, and a sensor module. Gas can flow through the central module from a valve inlet to a valve outlet. The control module is arranged directly on the central module and is configured to regulate the flow of gas through the central module with a throttling element arranged fluidically between the valve inlet and the valve outlet, with the sensor module being arranged directly on the central module.

[0008] The invention is therefore based on the objective of overcoming the aforementioned disadvantages and providing a flexible and modular gas control valve for electronic pressure control and, in particular, zero-pressure control.

[0009] This problem is solved by the combination of features according to claim 1.

[0010] According to the invention, a gas control valve for electronic pressure control, in particular zero-pressure control, of a gas-air mixture at a gas boiler is proposed. The gas control valve comprises a central module, a control module, and a sensor module, wherein the central module is permeable to gas flow from a valve inlet to a valve outlet. The control module can be arranged directly on the central module and is configured to regulate or adjust the gas flow through the central module. For this purpose, the control module has a throttling element arranged fluidically between the valve inlet and the valve outlet, which is in particular a valve cone interacting with a valve seat.According to the invention, the sensor module can be arranged directly on the central module and has at least one sensor which is in operative communication with the gas flowing through the central module via a gas inlet arranged fluidically between the throttling element and the valve outlet and which is designed to detect a pressure difference between the gas flowing through the central module and air having a reference pressure, for example as differential pressure or as mass flow, for pressure control or zero-pressure control.

[0011] A key aspect of the invention is therefore to tap the pressure for the sensor module, particularly at the gas control valve or its central module, and not outside the gas control valve, as is usually the case in the prior art. This significantly reduces cable lengths and response times.

[0012] The gas control valve is preferably a unit with several modules that can be arranged on the central module and which can be replaced if necessary, in case of damage or maintenance.

[0013] Another advantageous variant involves the sensor module having two sensors. If at least two sensors are provided, this results in redundant sensor technology, which increases the safety and accuracy of the measurement.

[0014] Furthermore, the values ​​recorded by the sensors can be correlated with each other and / or with stored historical data, and deviations can be compensated for, so that the sensors do not need to be calibrated, or at least not manually calibrated. In particular, deviations that occur over the lifespan of the sensors and, for example, slowly increasing deviations, can be detected and compensated for, or the sensors can be calibrated automatically.

[0015] An advantageous embodiment also provides that the at least one sensor is a mass flow sensor, which is configured to detect the pressure difference by measuring a mass flow between the gas inlet and an air inlet of the sensor module that is in operative communication with the air.

[0016] Furthermore, at least one sensor can be a differential pressure sensor, which is designed to detect the pressure difference by measuring a differential pressure between the gas flowing through the central module downstream of the control module and the air at an air inlet of the sensor module, from which the gas-air mixture is formed.

[0017] If a second or additional sensors are used, they can be of the same or different types. For example, with two sensors, both can be differential pressure sensors or mass flow sensors. Furthermore, with two sensors, one can be a differential pressure sensor and the other a mass flow sensor, meaning the flow rate values ​​are based on different measurement methods, thus further increasing safety.

[0018] A dust filter can also be provided at the air inlet of the sensor module. This protects at least one sensor from contamination and thus makes the entire gas control valve more robust and less prone to malfunctions.

[0019] The sensor module can also directly incorporate control electronics, which are designed to determine an average value from the respective values ​​measured by the two sensors and / or to compare and / or validate the values ​​measured by the sensors. This validation can be performed by comparing the values ​​with each other or with historical values. The control electronics can also directly control the control module and regulate the flow through the gas control valve by means of the throttling element.

[0020] To enable external evaluation of the values ​​or status information acquired by the at least one sensor or other components of the gas control valve, the gas control valve, and in particular the sensor module, may also have at least one communication interface. This interface allows, for example, the transmission of sensor-acquired values, status information, and / or error information to a higher-level control unit of the gas boiler. Calibration values, status information, and / or error information from the control module can also be transmitted via the communication interface.

[0021] Furthermore, the gas control valve, and in particular the sensor module, can include a power supply unit for powering the control electronics and / or at least one sensor. This unit can be integrated into the sensor module, but alternatively, it can be implemented on a mainboard of a boiler safety electronics unit or the boiler electronics of the gas boiler, so that no space needs to be provided for it within the sensor module or its housing.

[0022] According to the invention, the central module and the sensor module have corresponding mounting interfaces, allowing the sensor module to be directly attached to the central module. The central module provides mounting interfaces on several sides, enabling the sensor module to be attached to any of these sides. This allows the sensor module to be mounted on different sides of the central module as needed, thus providing a gas control valve adapted to the varying installation space requirements of different gas boilers. The mounting interfaces, which can be designed, for example, as screws, snap connectors, locking connectors, or clamps, also ensure quick and easy replacement of defective components.However, the sensor module does not necessarily have to be located directly on the central module, but can be connected to it, for example, via the fluid line mentioned below.

[0023] Preferably, the central module and the sensor module also have corresponding fluid interfaces through which the at least one sensor is connected to the gas flowing through the central module downstream of the control module. The fluid interfaces can be connected directly and / or via a fluid line. In the case of a direct connection, the fluid interface(s) of the sensor module are directly connected to the fluid interface(s) of the central module, which can be achieved, for example, by a locking mechanism on flowable nozzles. Because the fluid interfaces can also be connected via a fluid line, or, if required, several fluid lines, the sensor module can also be arranged at a distance from the central module. Such fluid lines can be, for example, flexible hoses or rigid pipes.

[0024] It is further preferably provided that the fluid interface of the central module is connected to the gas inlet of the sensor module, which opens downstream of the control module into a gas-flowing area of ​​the central module. The inlet, or the position at which it opens into the central module, forms the aforementioned first measuring point. In relation to a main flow restrictor that may be provided in the gas boiler, the inlet, or the first measuring point, is located, in particular, downstream of the control module and upstream of the main flow restrictor, and also within the gas control valve. The inlet is pressurized with the gas and is shielded from the gas flow by a screen that covers the inlet in the direction of gas flow. Due to the screen, the gas therefore does not flow directly past the inlet, which is located in a flow-stabilized area.It lies in a flow shadow, so that the value recorded by the sensors is not distorted.

[0025] Particularly preferably, the central module has a housing which has an opening downstream of the control module, covered by a lid. A seal is provided between the lid and the housing, with the shielding being formed by the lid and / or the seal.

[0026] The inlet itself can be provided in the lid or the housing, whereby the shielding can be formed not only by the lid or the seal, but alternatively by an additionally provided cover body or the housing itself.

[0027] To prevent damage to the sensor from condensation or moisture in general, the sensor module can also have at least one condensate drain. Such a condensate drain is designed to collect and / or remove condensate or moisture that forms in the sensor module, particularly on the two sensors. This further increases the robustness and service life of the sensor module and, consequently, the entire gas control valve. The condensate drain can be implemented as a sensor housing in which the sensors are arranged, ensuring that the moisture or condensate is directed away from the sensors and cannot enter them.

[0028] In addition, the gas control valve may have a safety module which is arranged upstream of the control module on the central module and is designed to prevent the flow of gas through the central module in a closed position and to release it in a free position.

[0029] The features disclosed above can be combined in any way, provided that this is technically possible and they do not contradict each other.

[0030] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 Schematic diagram of a gas-air system of a gas boiler; Fig. 2 A first variant of a gas control valve; Fig. 3 A second variant of a gas control valve; Fig. 4 A third variant of a gas control valve; Fig. 5 Schematic diagram of a gas control valve.

[0031] The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and / or structural features. Figure 1 Figure 1 schematically shows a part or section of a gas boiler, and more precisely, the schematic structure of a gas-air system of a gas boiler, where a Venturi mixer is depicted as mixing device 3, in which air at a pressure p0 is drawn from the environment through an air inlet L by a blower 4. In the mixing device 3, the incoming air and a fuel (gas) flowing in through the fuel supply G are mixed to form a gas-air mixture.

[0032] The gas flowing in from the fuel supply G passes through a safety module 10 with a safety valve 11, a control module 20 with a valve 21 (for example, a proportional valve), and the main flow restrictor 2. The safety valve 11 preferably has an open and a closed position, in which the flow of fuel through the safety valve 11 is blocked. The safety valve 11 can be moved into the respective position by an actuator 12 provided for this purpose in the safety module 10. The safety valve 11 can also be manually operated, either additionally or alternatively. The valve 21 is designed to control the volumetric or mass flow rate of the gas, so that the gas flow through the valve 21 to the mixing device 3 can be adjusted or controlled. By adjusting or controlling the valve 21, the mixing ratio of the gas-air mixture can thus be set.For this purpose, the valve 21 is connected to an associated actuator 22, for example a stepper motor, by which the flow position of the valve 21 can be changed or adjusted, wherein the actuator 22 is controlled by a control device (not shown), which may be integrated into the sensor module 30, with a manipulated variable.

[0033] In the sensor module 30, two differential pressure sensors 31, 32 are provided in the specific example shown. Each sensor is configured to determine the differential pressure between the pressure p2 of the gas upstream of the main flow restrictor 2 and downstream of the valve 21, and a reference pressure. The reference pressure is preferably the ambient pressure p0 or the pressure p1 of the air in an air-carrying supply line to the mixing device 3. Alternatively, however, only one differential pressure sensor 31 may be provided.

[0034] The gas-air mixture is conveyed by the blower 4 to a burner of the gas boiler (not shown), where the fuel-air mixture is to be burned.

[0035] In particular, the valve 21 of the control module 20 is set by the actuator 22 such that the sensor module 30 detects a pressure difference of 0 bar.

[0036] In addition to the first sensor 31 and the second sensor 32, the sensor module 30 also has control electronics 33, through which the differential pressures detected by the sensors 31, 32 are compared and validated, and a common differential pressure is determined for controlling the valve 21 via the actuator 22.

[0037] The safety module 10, the control module 20 and the sensor module 30 are provided on the central module 40, which can be permeated by gas from its valve inlet 41 to its valve outlet 42, so that together they form the gas control valve 1.

[0038] In the Figures 1 to 3 A single gas control valve 1 is shown, in which the sensor module 30 is fixed to or connected with the central module 40 in various configurations. This results in high flexibility regarding the required installation space as well as simple and quick replacement of the modules.

[0039] For this purpose, the central module 40 preferably has fastening interfaces (not shown) on each of its four sides around its longitudinal axis, which correspond to fastening interfaces (also not shown) of the sensor module 30.

[0040] At the gas control valve 1 according to Figure 2 The sensor module 30 is located on a first side and according to the Figure 3 arranged on a second side that is orthogonal to it. In Figure 4It is further shown that the corresponding fluid interfaces 36, 46 of sensor module 30 and central module 40 can alternatively be connected by a fluid line 37, so that the sensor module 30 can be connected according to the variant of Figure 4 not directly attached to the central module 40 but connected to it via pressure technology.

[0041] In Figure 5 A section of the central module 40 and the sensor module 30 is shown in cross-section.

[0042] The central module 40 is operated by the in Figure 5The gas flows through the valve inlet 41 (not shown) to the valve outlet 42, whereby the flow rate of the gas through the gas control valve 1 is adjustable or controllable by means of the throttling element 23, designed as a valve cone, and the valve seat 24 of the control module 20. The sensor module 30, which is pressure-connected to the gas via the fluid interfaces 36, 46, is designed for electronic pressure control or for detecting the pressure difference between the gas and the surrounding air. For this purpose, the sensor module 30 has an air inlet 34, on which a dust filter 35 is provided to prevent the ingress of dirt particles into the sensor module 30. Furthermore, a condensate drain 38 is provided on the air inlet 34, through which condensate formed at the sensors 31, 32 can be discharged into the environment via the air inlet 34.

[0043] A gas inlet 44 of the sensor module 30 is provided at the fluid interface 46 of the central module 40, which opens into the gas-flowed area 43 of the central module 40, wherein the gas inlet 44 is covered by a shield 45 in the flow direction i.e. towards the valve outlet 42.

[0044] The housing 47 of the central module 40 has an opening in the area 43 which is closed with a cover 48, the cover 48 forming integrally the shield 45.

[0045] Alternatively, a seal 49 provided between housing 47 and cover 48 or a separate component can also form the shielding 45.

[0046] Due to the shielding 45, the inlet is located in a flow-calmed area, so that there are no or at least less pressure fluctuations at the sensors 31, 32 in the sensor module 30.

[0047] The invention is not limited in its implementation to the preferred embodiments specified above. Rather, a number of variants are conceivable which make use of the solution presented even in fundamentally different designs.

Claims

1. A gas control valve (1) for electronic pressure control of a gas-air mixture in a gas heater, wherein the gas control valve (1) has a central module (40), a control module (20), and a sensor module (30), wherein the central module (40) can be flowed through by gas from a valve entrance (41) to a valve exit (42), wherein the control module (20) is arrangeable immediately at the central module (40) and is configured to control a through-flow of the gas through the central module (40) with a throttle element (23) being fluidically arranged between the valve entrance (41) and the valve exit (42), wherein the sensor module (30) is arrangeable immediately at the central module (40) and has at least one sensor (31, 32) which is in operative connection with gas flowing through the central module (40) via a gas inlet (44) that is fluidically arranged between the throttle element (23) and the valve exit (42) and which is configured to detect a pressure difference between the gas flowing through the central module (40) and air having a reference pressure for pressure control, wherein the central module (40) and the sensor module (30) have attachment interfaces that correspond with one another and the sensor module (30) is immediately fixable to the central module (40), and the central module (40) provides attachment interfaces at multiple sides and the sensor module (30) is alternatively fixable at each of the multiple sides.

2. The gas control valve according to claim 1, wherein the at least one sensor (31, 32) is a mass flow sensor and is configured to detect the pressure difference by measurement of a mass flow between the gas inlet (44) and an air inlet (34) of the sensor module (30) that is in operative connection with the air.

3. The gas control valve according to claim 1 or 2, wherein the at least one sensor (31, 32) is a differential pressure sensor and configured to detect the pressure difference by measurement of a differential pressure between the gas flowing through the central module (40) downstream of the control module (20) and the air at an air inlet (34) of the sensor module (30), from which the gas-air mixture is formed.

4. The gas control valve according to claim 2 or 3, wherein a dust filter (35) is provided at the air inlet (34) of the sensor module (30).

5. The gas control valve according to any one of the preceding claims, wherein the sensor module (30) has two sensors (31, 32).

6. The gas control valve according to the preceding claim, wherein the sensor module (30) has control electronics (33) that are configured to determine an averaged value from each of the values measured by the sensors (31, 32) and / or to compare and / or to plausibilise the values measured by the sensors (31, 32).

7. The gas control valve according to the preceding claim, wherein the control electronics (33) have at least one communication interface and / or one voltage supply unit for voltage supply of the control electronics (33) and / or of the sensors (31, 32).

8. The gas control valve according to any one of the preceding claims, wherein the central module (40) and the sensor module (30) have fluid interfaces (36, 46) that correspond with one another, via which the at least one sensor (31, 32) are connected to the gas flowing through the central module (40) downstream of the control module (20), wherein the fluid interfaces (36, 46) are immediately connectable to one another and / or via a fluid line (37).

9. The gas control valve according to the preceding claim, wherein the fluid interface (46) of the central module (40) is connected to the gas inlet (44) that, downstream of the control module (20), opens into an area (43) of the central module (40) through which gas flows, wherein the gas inlet (44) is in operative connection with the gas and is shielded from the gas flow by a shield (45) which covers the gas inlet (44) in a flow direction of the gas.

10. The gas control valve according to the preceding claim, wherein the central module (40) has a housing (47) that has an opening covered by a lid (48) downstream of the control module (20), wherein a seal (49) is provided between the lid (48) and the housing (47), and wherein the shield (45) is formed by the lid (48) and / or the seal (47) or a shielding body.

11. The gas control valve according to any one of the preceding claims, wherein the sensor module (30) has at least one condensate outlet (38) that is configured to collect condensate generated in the sensor module (30) and / or to remove it from the sensor module (30).

12. The gas control valve according to the preceding claim, wherein the condensate outlet (38) is configured to collect condensate generated at the at least one sensor (31, 32) and / or to remove it from the sensor module (30).

13. The gas control valve according to any one of the preceding claims, wherein the gas control valve (1) has a safety module (10) that is arranged at the central module (40) downstream of the valve entrance (41) and upstream of the control module (20) and is configured to prevent the flow of gas through the central module (40) when in a blocking position and to allow it in a passage position.