ES2960744T3 - Gas heating appliance with harmful gas detector - Google Patents

Abstract

The present invention describes a gas-powered heating apparatus adapted to connect to a common chimney through flues to discharge smoke and introduce outside air. The gas heating appliance includes a housing, a burner, a gas valve, a fan, a harmful gas sensor and a controller. The harmful gas sensor is arranged in the housing to detect a concentration of harmful gases in the air inside the housing. The harmful gas sensor can be used to detect one, several or all of the CO, CO2, NOx and other harmful gases normally found in fumes. The controller is electrically connected with the burner, gas valve, fan and harmful gas sensor to control the fan and/or burner and/or gas valve based on the detection of the harmful gas sensor. In this way, when there is smoke recirculation inside the casing, it will be quickly detected and measures can be taken against the smoke recirculation. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Gas heating appliance with harmful gas detector

FIELD OF THE INVENTION

The present invention relates to a gas heating device, specifically a gas heating device capable of detecting the quality of the air inside it.

BACKGROUND OF THE INVENTION

Gas heating appliances typically include gas water heaters and gas boilers. A typical gas boiler is intended to heat a transfer fluid, such as water, and pump it through a boiler circuit. The boiler circuit is usually connected by means of suitable valves to space heating appliances such as radiators or underfloor heating coils, so that the heat produced by the boiler can be used for space heating purposes. A gas boiler usually generates fumes that contain harmful gases, such as CO (carbon monoxide), CO2 (carbon dioxide), NOx (nitrogen oxides), etc., which must be evacuated outside. For multi-flue configurations, it is possible to connect multiple boilers in multi-family homes to a common chimney using vents to evacuate fumes. The chimney can consist of a concentric duct made up of internal and internal coaxial tubes, where usually the internal tube is intended to evacuate smoke and the external tube to introduce fresh air. US patent publication US 2015/0096504 Al describes an example of such boilers. A circulating hot water supply device 1 with an exhaust pipe 12 for evacuating the combustion gases from the burner 3 and an air supply pipe 13 covering the exhaust pipe 12 and connected to a communicating suction duct 15 with the air inlet of the combustion fan 14 to introduce external air for combustion.

However, there are certain risks. If a user's non-return valve installed in the vents is damaged or missing, flue gases in the chimney could flow back into the boiler. The same could happen if the seal on your own or another user's exhaust pipe is damaged. Return of fumes could result in combustion failure. Since returning fumes can replace fresh air or reduce the oxygen concentration in the air inside the boiler, the boiler will not ignite or the combustion flame will go out, causing corresponding fault codes to be displayed. Additionally, fumes can enter the family home and result in dangerous pollution if the boiler's outer casing is not hermetically sealed. German patent publication DE 30 08 399 Al describes a return flow sensor 10 installed in an exhaust duct 9 and connected to an actuating device 8, which in turn is connected to a solenoid valve 7. In case of return of exhaust gases, the sensor 10 detects it and activates the actuating device 8 of the solenoid valve 7 to interrupt the gas supply to the burner 2.

Publication US5,797,358 describes a water heater equipped with a carbon monoxide sensor positioned adjacent to a fume hood to detect the presence of an unacceptable level of carbon monoxide resulting from a blocked vent pipe, and send a signal to a microprocessor to prevent or interrupt the operation of the burners. Publication CN 104110869 A describes a gas water heater with a sensor for detecting gas concentration, and a controller for closing the gas valve when the concentration detected by the gas sensor exceeds a predetermined threshold.

Publication DE 298 02 545 Ul describes a heating appliance with a gas exhaust duct and a flow control device 24 with an orifice 32 in the installation space of the heating appliance for operating the appliance depending on the ambient air. , and a first connection piece 26 for a gas exhaust pipe 18 and a second connection piece 30 for the external exhaust gas ducts. The two connecting parts 26, 30 are placed horizontally next to each other, so as not to significantly increase the overall height of the heating device. An exhaust gas sensor 34 installed laterally in the first connecting piece 26 immediately adjacent to the hole 32 detects the accumulation of exhaust gases. If there are obstructions in the chimney, the exhaust gases pass through hole 32 into the environment. The exhaust gases are detected by the exhaust gas sensor 34 and the heater is automatically restarted after a pause of around 20 minutes.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a gas heating appliance capable of monitoring the air quality within the appliance and performing certain operations to improve the air quality and alert installers or users if the air quality is worsening due to the recirculation of smoke, thus improving the safety of the device.

By means of the present invention, a gas heating device is provided adapted to connect to a common chimney by means of ventilation ducts to evacuate smoke and introduce air from outside. The gas heating appliance includes a chamber, a burner, a gas valve, a fan, a harmful gas sensor and a controller. The chamber has a first port and a second port on the opposite side to the first port, where one of them is intended to evacuate smoke and the other to introduce air from outside. The burner is arranged in the chamber for combustion of a mixture of introduced outside air and fuel gas to generate flame. The gas valve is associated with the burner for the purpose of regulating the supply of fuel gas to the burner. The fan is arranged in the chamber to push the air introduced from the outside towards the burner and cause the fumes to be evacuated to the outside through the ventilation ducts and the common chimney. The harmful gas sensor is arranged in the chamber to detect any concentration of harmful gases in the air inside the chamber. The harmful gas sensor can be used to detect gases such as CO, CO2, NOx and other harmful gases commonly present in smoke. The controller is electrically connected to the burner, gas valve, fan and harmful gas sensor to control the fan and/or burner and/or gas valve based on the activation of the harmful gas sensor. The controller is configured to initiate a stand-by operation when excessive harmful gases are detected while the appliance is in stand-by mode, and the stand-by operation includes activation of the fan to evacuate fumes into the air inside. of the camera. In this way, when there is recirculation of smoke inside the chamber, it can be quickly detected to take actions to prevent said recirculation.

Thus, the excess of harmful gases is identified when the harmful gas sensor detects that the concentration of harmful gases is equal to or greater than a first predetermined threshold.

Preferably, stand-by operation also includes gradually increasing the fan speed approximately every two minutes.

Additionally, stand-by mode operation includes stopping the fan if the harmful gas sensor detects that the concentration of harmful gases decreases to a second threshold within a first period of time from when an excess of harmful gases is detected.

Additionally, during stand-by operation a fault code is displayed if the harmful gas sensor detects that the harmful gas concentration is not reduced to a second threshold within a first period of time from when the excess of harmful gases, in order to notify the user or installer of the existence of poor air quality inside the chamber.

Preferably, operation in stand-by mode also provides for keeping the fan running to continue evacuating smoke until the user or the installer stops it, and disabling the combustion of the burner to prevent risks or damage.

The second threshold is equal to or less than the first threshold.

In one embodiment, the controller is configured to stop combustion of the burner and then enter stand-by operation when the appliance operates in residential hot water mode for a second period of time after excessive harmful gases are detected. In this way it is possible to guarantee a comfortable supply of residential hot water. For example, a user who is showering will not have the supply suddenly interrupted.

In one embodiment, the controller is configured to stop combustion of the burner and then enter stand-by operation when excess harmful gases are detected while the appliance is operating in space heating mode.

In one embodiment, the appliance further includes a counter capable of counting each time an excess of harmful gases is detected and the burner is in operation, with the controller configured to display a fault code when the number of times reaches a predetermined value within of a period x.

Preferably, the controller is also configured to keep the fan running and disable burner combustion.

In one representation, the harmful gas sensor is placed next to the port for introducing outside air. Since the sensor is positioned at the fresh air inlet, the recirculation of smoke from the other boilers can be quickly detected when the appliance is in stand-by mode.

In an alternative representation, the appliance also includes an air duct in the chamber to conduct outside air towards the burner, and where the harmful gas sensor is located at the inlet of the air duct, which is better for detecting recirculation. of smoke when the appliance is operating because the fan is sucking in fresh air and the recirculation of smoke from other boilers or from the thermal module of that same boiler can be quickly detected.

BRIEF DESCRIPTION OF THE DESIGNS

For a more complete understanding of the present invention and its advantages, we will now refer to the following descriptions considered together with the accompanying designs:

Fig. 1 is a schematic diagram showing a gas boiler connected to a common chimney by means of ventilation ducts in accordance with a first representation of the present invention.

Fig. 2 is a schematic diagram showing a gas water heater connected to a common chimney by means of ventilation ducts in accordance with a second representation of the present invention.

Fig. 3 is a flow chart illustrating the operation of the gas boiler of Fig. 1.

DETAILED DESCRIPTION OF PREFERRED REPRESENTATIONS

We will now refer to the designs to describe in detail the preferred embodiments of the present invention. However, such representations cannot be used to limit the present invention. Changes in structure, method, function and the like that would be obvious to a person of ordinary skill in the art are also protected by the present invention.

The gas heating appliance object of the present invention is suitable for home applications and can operate on fuel gas, such as natural gas, mains gas, liquefied petroleum gas, methane, etc. Gas heating appliances can be used to heat residential water to meet users' hot water demand, such as gas water heaters or gas boilers capable of providing both residential hot water and space heating. In the following representations we will explain in detail the operation of a gas boiler and a gas water heater under the present invention.

Referring to Fig. 1, in a first representation of the present invention, a gas heating appliance and chimney system 100 includes a gas boiler 1, a common chimney 9, and ventilation ducts 8 connected between the boiler to gas 1 and common chimney 9. Common chimney 9 may be connected to multiple gas heating appliances in multi-family dwellings or in multi-vent configurations; The chimney can be inside or outside the building. Each of the ventilation ducts 8 and the common chimney 9 can have the form of a concentric duct composed of the internal coaxial tubes 81, 91 and the external tubes 82, 92, where one of the pairs of tubes is intended to evacuate smoke and the another is intended to introduce fresh air from outside. In this representation, the internal tubes 81,91 are for evacuating fumes and the external tubes 82, 92 are for introducing fresh air.

The gas boiler is preferably a condensing boiler. The boiler 1 includes a chamber 11, a thermal module 121, a gas valve 122 and a fan 123, all within the chamber 11. The chamber is usually sealed with suitable means to prevent gas leaks. The chamber 11 defines a first port 181 that communicates with the internal tubes 81, 91, and a second port 182 on the side opposite the first port and that communicates with the external tubes 82, 92. The thermal module 121 generally includes a cylindrical burner combined with ignition and monitoring electrodes for the combustion of a mixture of fresh air and fuel gas to generate flame, and an integral condensation heat exchanger consisting of a number of coils arranged around the cylindrical burner. Gas valve 122 is connected to a fuel gas supply to line 1221 and is operable to regulate the fuel gas supply to the burner. The purpose of the fan 123 is to direct the fresh air containing oxygen for combustion preferably through an air duct 13 towards the burner, and to cause the evacuation of the fumes towards the ventilation ducts through a smoke duct 281.

Chamber 11 contains a plate heat exchanger 14. A residential water line 151 is provided to introduce cold water passing through the plate heat exchanger 14 to absorb heat, and extract the hot water for sanitary use, for example to bathe or shower. A transfer fluid line 152 is connected to the integral condensation heat exchanger to obtain heat, and to the external space heating appliances to radiate heat into the rooms. The transfer fluid line 152 may also be installed to pass through the plate heat exchanger 14: however, the two connections 151, 152 are physically insulated to prevent contact between the residential water and the transfer fluid. but allowing heat exchange between both. A flow sensor 153 is preferably arranged at the beginning of the residential water line 151 and can generate a signal when there is a flow of water passing through the line 151 to satisfy the demand for residential hot water.

The chamber 11 further contains a harmful gas sensor in an appropriate position to detect the concentration of harmful gases in the air within the chamber. Harmful gases can be any type of harmful gas contained in smoke, such as CO, CO2, NOx, etc. In other words, if there is smoke recirculation from the common chimney 9 or other gas heating appliances in the system, or even from the gas boiler 1 itself, such smoke recirculation can be detected by this gas sensor. In this representation, the harmful gas sensor may consist of a CO2 sensor such as the TELAIRE® T6713 series that operates with NDIR (non-dispersive infrared) technology. NDIR technology uses a broadband infrared (IR) emitter that covers all wavelengths relevant to a given set of gases to be measured. An optical wavelength filter added to the gas sensor allows passage of the range of IR wavelengths at which a specific gas, for example CO2, absorbs IR energy, and then the gas sensor produces a signal proportional to the amount of IR energy absorbed by the relevant gas. In this representation, the harmful gas sensor 16 is preferably placed at the inlet of the air duct 13, which is better for detecting smoke recirculation when the boiler is in operation because the fan 123 is sucking in fresh air and thus recirculation of smoke from other boilers or from the thermal module of the boiler itself can be quickly detected.

The chamber 11 also includes a controller 17 electrically connected to the burner, the gas valve 122, the fan 123, the flow sensor 153 and the harmful gas sensor 16. The controller 17 is configured to control various operations of the gas boilers. , which will be described in detail with reference to the flow diagram of Fig. 3. The controller 17 may consist of a logic control circuit formed by a number of electronic components connected according to certain wiring patterns; or it can be a microcontroller (MCU) to store programming instructions; or also consist of integrated chips for specific use, such as configurable logic block arrays (FPGAs).

Fig. 2 shows a gas heating appliance and a chimney system 200 in a second representation of the present invention, in which a gas water heater 2 is connected to a common chimney 9 by means of ventilation ducts 8 The gas water heater 2 includes a hermetic chamber 21 with a first port 281 and a second port 29, a burner 221 combined with ignition and monitoring electrodes 2211,2222, a finned tube heat exchanger 222 connected to a. incoming cold water line 251 and a hot water outlet line 252, a gas valve 23 connected to a fuel gas supply line 231, and a fan 24 to blow outside air and evacuate fumes to the exhaust ducts. ventilation 8 through an extraction hood 28. The harmful gas sensor can also be a CO2 sensor placed next to the second port 29 through which fresh air from outside is introduced. Since the sensor is positioned at the fresh air inlet, the recirculation of smoke from the other boilers can be quickly detected when the appliance is in stand-by mode. The chamber 21 also includes a controller 27 electrically connected to the burner 221, the gas valve 23, the fan 24, the flow sensor 253 and the harmful gas sensor 26. Since the components of the present representation are the same or similar to those of the first representation, the detailed explanation of their functional operation is omitted for the sake of brevity and simplicity.

Referring to Fig. 3, in conjunction with Fig. 1, a flow chart of the control operations of the gas boiler in accordance with the first representation of the present invention is shown. The controller 17 monitors the CO2 concentration of the air within the chamber 11 via the CO2 sensor 16 in real time or periodically (step 411). If the CO2 concentration is equal to or greater than a first threshold, such as 9,000 ppm (step 411), which implies an excess of CO2, the controller 17 further checks whether the burner is operational using the monitoring electrode (step 413 ). If the burner is not in operation, meaning that the gas boiler is in standby mode, the controller 17 initiates standby operation. The controller 17 first activates the fan 123 to evacuate fumes from the air so that the quality of the fresh air becomes suitable for ignition (step 421). In a preferred embodiment, the fan 123 operates at a low speed initially and then increases it step by step. A person with sufficient knowledge can regulate the fan speed by adjusting the PWM signal to the fan current. During operation of the fan, the controller 17 continues to check whether the CO2 concentration is reduced to a second threshold within a first period of time from when the excess CO2 is detected (step 422). The second threshold is equal to or less than the first threshold. If the CO2 concentration decreases to the second threshold within the first time period, meaning that the air quality inside the chamber is adequate for proper ignition, the controller 17 stops the fan (step 423) and continues to monitor the CO2 concentration. Preferably, the controller can stop the fan after a certain time. If the CO2 concentration is not reduced to the second threshold within the first time period, implying that the air quality is not yet suitable for ignition, the controller 17 displays a fault code on a panel (not shown) of the gas boiler to remind the user to inspect the boiler and take appropriate measures to evacuate the fumes; preferably, the controller 17 also disables the combustion of the burner, for example by closing the gas valve 122 to avoid risks or damages, keeping the fan running to evacuate the fumes (step 424).

Back to step 413, if the burner is in operation, a smoke recirculation counter will count once (step 414), then the controller 17 will check whether the accumulated number of times reaches a certain value within a predetermined period (step 415). In this representation, the default value is five, and the default time frame is 24 hours. In this way, if the accumulated amount in the counter reaches five within the previous 24 hours, indicating that there is a high frequency of detection of excess CO2, the controller 17 displays a fault code, and preferably disables combustion. of the burner and keeps the fan on to evacuate the fumes (step 424); otherwise, the controller 17 further checks whether there is demand for residential hot water (step 416). Controller 17 may detect residential hot water demand through flow sensor 153; That is, if there is a flow of water in the residential water line 151, the flow sensor sends a signal to the controller 17, and then the controller 17 waits for a second period of time since excess CO2 is detected (around three hours) to ensure the comfort of hot water users (step 417). If there is no demand for residential hot water, for example if the boiler is operating in space heating mode, or if the second time period ends before excess CO2 is detected in residential hot water mode, the controller 17 interrupts the combustion of the burner by closing the gas valve 122 (step 418) and then enters stand-by operation mode. It is obvious to a qualified person that for a gas water heater, step 416 can be omitted because if the burner is operating the flow sensor will detect a flow of water at the same time, so there is no need to detect the "residential hot water demand".

Detection of harmful gases can also be used by an installer. During installation, the controller can carry out detection of harmful gases on site, and if excessive harmful gases are detected, the installer can inspect and take measures against smoke recirculation at the same time. Furthermore, since fumes often contain CO, CO2, NOx and other harmful gases, excess CO2 also reflects excess CO or NOx, and therefore excess CO and NOx can also be limited by CO2 detection. Similarly, for a condensing boiler, the risk of condensation in the air caused by flue gas recirculation can be reduced because the flue gas recirculation is quickly detected and the fan begins to evacuate the flue gas.

It is understood, however, that notwithstanding the numerous features and advantages of the present invention described herein, together with the details of the structure and operation of the invention, this description is purely illustrative, and changes may occur in aspects as quantity, shape, size and arrangement of parts within the principles of the invention and in the broadest sense of the terms with which the preceding claims are described.

Claims (13)

. A gas heating device (1, 2) adapted to connect to a common chimney (9) through ventilation ducts (8) to evacuate smoke and introduce air from outside, composed of: a chamber (11, 21) with a first port (181,281) and a second port (19, 29) on the opposite side to the first port, where one of the ports is intended to evacuate smoke and the other to introduce air from outside; a burner arranged in the chamber for the combustion of a mixture of air introduced from outside and fuel gas to generate flame; a gas valve associated with the burner for the purpose of regulating the supply of fuel gas to the burner; a fan arranged in the chamber to drive the air introduced from the outside towards the burner and cause the fumes to be evacuated to the outside through the ventilation ducts and the common chimney; a controller electrically connected to the burner, the gas valve and the fan, which additionally includes: a harmful gas sensor arranged in the chamber to detect possible concentrations of harmful gases that include at least one of the gases CO, CO2 or NOx in the air inside the chamber; The controller is electrically connected to the burner, gas valve, fan and harmful gas sensor to control the fan and/or burner and/or gas valve based on the detection made by the gas sensor. harmful; said controller is configured to initiate a stand-by operation upon detecting an excess of harmful gases when the appliance is in stand-by mode, and said stand-by operation includes activating the fan. 2. A gas heating appliance according to claim 1, wherein the excess harmful gases are identified when the harmful gas sensor detects that the concentration of harmful gases is equal to or greater than a first predetermined threshold. 3. A gas heating appliance according to claim 1, wherein the stand-by operation also includes gradually raising the speed of the fan. 4. A gas heating appliance according to claims 1 or 3, wherein the stand-by operation includes stopping the fan if the harmful gas sensor detects that the concentration of harmful gases decreases to a second threshold within a first period of time since an excess of harmful gases is detected. 5. A gas heating appliance according to claims 1 or 3, wherein the operation in stand-by mode includes displaying a fault code if the harmful gas sensor detects that the concentration of harmful gases does not decrease to a second threshold within of a first period of time from when an excess of harmful gases is detected. 6. A gas heating appliance according to claim 5, wherein the stand-by operation includes keeping the fan running and disabling combustion of the burner. 7. A gas heating appliance according to claims 6 or 5, wherein the second threshold is equal to or less than the first threshold. 8. A gas heating appliance according to any of claims 2-7 wherein the controller is configured to stop combustion of the burner and then enter into stand-by mode operation when the appliance operates residential hot water mode by a second period of time after detecting an excess of harmful gases. 9. A gas heating appliance according to any of claims 2-7 wherein the controller is configured to stop combustion of the burner and then enter into stand-by operation when an excess of harmful gases is detected while the appliance is operating in space heating mode. 10. A gas heating appliance according to claim 1, further including a counter capable of counting each time an excess of harmful gases is detected and the burner is in operation, and wherein the controller is configured to display a code of fails when the number of times reaches a predetermined value within a period x. 11. A gas heating appliance according to claim 10, wherein the controller is also configured to keep the fan running and disable combustion of the burner. 12. A gas heating appliance (2) according to claim 1, wherein the harmful gas sensor (26) is placed next to the port for introducing outside air. 13. A gas heating appliance (1) according to claim 1, which further includes an air duct (13) in the chamber for conducting outside air towards the burner, and in which the harmful gas sensor (16 ) is located at the entrance of the air duct.