MX2012007938A

MX2012007938A - Electronically-controlled tankless water heater with pilotless ignition.

Info

Publication number: MX2012007938A
Application number: MX2012007938A
Authority: MX
Inventors: Gilberto Sánchez Villalobos; Epigmenio Guzmán Cabrera; Flavio Sa L Gocobachi
Original assignee: Calentadores De América S A De C V
Priority date: 2012-07-06
Filing date: 2012-07-06
Publication date: 2014-01-17
Also published as: CL2013000166A1; US20140007821A1; AR089204A1; BR102013000487A2; CO6950089A1

Abstract

The tankless water heater of the present invention is operated by means of an electronic card or controller without a flow detector of the electromechanical type. Said electronic controller is intended to manage the operation of each of the components of the system, optimizing the consumption of gas and reducing the emission of pollutant gases, since it is pilotless, the multi-burner only ignites when certain conditions or predefined requirements in the electronic controller logic are met, thus being turned off most of the time. Other factors contributing to improved water heater efficiency are: a) the water tank design which at the bottom has a water chamber surrounding the combustion chamber, and b) the use of a finned heat exchanger, which together with a core, successfully utilizes most of the thermal energy contained in the combustion gases. An air deflector device stops the entry of air currents at the top of the heater, thus stopping potential flame reversing and even flame ext inction in the multi-burner.

Description

PILOT-FREE WATER WATER HEATER WITH CONTROL SYSTEM ELECTRONIC Field of the Invention The present invention relates generally to water heating equipment that maximizes its efficiency by reducing thermal losses through the use of a finned tube type heat exchanger and a water chamber surrounding the combustion chamber. This water heater is capable of permanently providing a supply of hot water and has an electronic control system that governs its operation.

BACKGROUND OF THE INVENTION To meet a constant demand for hot water with the greatest possible savings in fuel gas, there are currently on the market water heaters, instantaneous or quick recovery. In the case of the first, however, the problem that must be met with a minimum hydraulic pressure of operation is presented; In addition, in regions where the ambient temperature may fall below zero degrees Celsius, the water contained in the coil of this type of heater may become freezing and with its SUMMARY The rapid recovery step water heater of the present invention operates by means of an electronic card or controller and eliminates the need for an electromechanical type water flow detector. Said electronic controller governs the operation of each of the components of the system optimizing the consumption of fuel gas and minimizing the emission of polluting gases since it does not have a pilot and the burner of several bodies ignites only when certain conditions or pre-established requirements are met. logic of the electronic controller so it stays off most of the time. Other factors that contribute to improving the efficiency of the water heater are: a) the design of the water tank that in its lower part has a water chamber that surrounds the combustion chamber minimizing thermal losses in that area and b) the use of a finned heat exchanger that, in combination with a core, takes advantage of most of the thermal energy contained in the combustion gases. Another characteristic characteristic of the present invention is that it has an air deflector device that prevents the entry of air currents through the upper part of the heater, thus preventing possible flash backs, and even the extinction of the flame in the burner. several bodies. respective volumetric expansion causes the rupture of said coil and consequently the use of the equipment. The PCT patent WO / 2007/057864 offers an alternative to solve the problem related to the freezing of water in this type of heaters, however, the problem of the minimum hydraulic pressure of operation has not yet been solved, so the heaters of the Instantaneous type are still not suitable for use in most existing hydraulic facilities, forcing that in many cases it is necessary to adapt or integrate other elements to the system for proper operation, increasing the cost of the equipment.

Because the water pressure is not constant in hydraulic installations, the need arises to create a water heater as described in the previous paragraph looking for a saving of fuel gas, and that is suitable for the various hydraulic installations to meet a constant demand for hot water.

The equipment mentioned in the United States patents United States of America US 7,982,164 B2 and US7,985,943 B2, being of the type of quick recovery step, not instantaneous, do not require a minimum hydraulic pressure of operation for their correct operation. However, the heaters described in both patents make use of a flow detector electromechanical to send the hot water demand signal to the electronic controller. This flow detector has a nucleation point for the precipitation of tartar, so that, if used in regions where the water of the hydraulic network contains high concentrations of salts, the operation of the flow detector could be affected, altering the equipment operation.

In the water heater of the present invention the need for an electromechanical type water flow detector is eliminated, replacing it with a system composed of two temperature sensors placed one at the entrance of the cold water and the other at the exit of hot water in a way that allows us to deduce that the flow condition occurs when registering a difference of 4 ° C between the two temperature sensors. This water heater has an ionized ignition system and an electronic controller that gives the ignition order under the following conditions: a) When there is a flow signal and the temperature sensor placed at the hot water outlet detects a temperature lower than the maximum cut-off temperature predetermined in the electronic controller. b) It will also turn on when the temperature detected by both sensors is less than a pre-set value in the electronic controller as the minimum ignition temperature.

In this way the water heater will only turn on when hot water is required, under the settings inserted in the electronic controller.

Synthesis of the Invention The water heater of the present invention has been designed in such a way that it has the following elements: A water tank resistant to corrosion, which in its lower part extends long enough to constitute a water chamber that surrounds the combustion chamber located on a multi-body burner so that the loss of heat towards the outside is minimized. that area, and in its upper part has a finned heat exchanger, which allows the capture of most of the thermal energy contained in the combustion gases and transfer it to the water contained in the tank; a burner with a power between 8.7 and 13.0 kw to which gas is supplied fuel from a solenoid valve system; a bimetallic temperature detector whose function is to avoid overheating of the water inside the equipment; two temperature sensors located respectively at the entrance of the cold water and the hot water outlet, a first electrode that generates a spark for the ignition of the burner and a second electrode that detects the change of current produced in the first electrode by ionization effect after igniting the burner; an electronic controller that, upon fulfilling the hot water demand conditions and / or a water temperature in the heater less than the pre-established one, sends a current to the first electrode in such a way that it allows it to generate the ignition spark of the burner; a system of electrovalves that allow the gas to pass safely to the burner once the electronic controller has sent the current for the generation of the spark in the first electrode, - a screen in direct communication with the electronic controller in which The user can observe the status of the water heater at a certain time.

The whole set of components of the present invention operate the water heater privileging the safety of the user and the water heater itself and maximizing fuel gas savings without a pilot that is permanently on.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a general view of the water heater of the present invention.

Figure 2 shows the main components that are: water tank, drainage valve, external body, solenoid valve system, electronic controller and air dispersing device, by means of an exploded view.

Figure 3 is a cross-sectional view of the upper part of the heater.

Figure 4 is a cross-sectional view of the lower part of the heater.

Figure 5 is a view of the electronic card or controller.

Detailed description of the invention The water heater (1) of the present invention illustrated in Figure 1 is designed to withstand a pressure greater than 1.OMPa. The water tank (2) is made of steel and the areas that are in contact with the water are porcelain to prevent corrosion.

The cold water inlet (3) is located in the upper right part of the water tank (2), in the same way the hot water outlet (4) is located in the upper left part of said tank (2). Additionally, in the lower part of the water tank (2) there is a connection (5) that connects the water tank (2) with the outside so as to allow the draining and cleaning of the water tank (2) by means of the placement of the water tank (2). a valve (6).

The fuel gas is supplied to a multi-body burner (7) by means of a solenoid valve system (8), thus providing the energy required for water heating. The power of the burner of several bodies (7) will depend on the size of the equipment that in turn will depend on the user's requirements.

The multi-body burner (7) and a solenoid valve system (8) regulate the passage of gas safely. This system of electrovalves (8) is protected from thermal radiation by means of a screen (9). The solenoid valve system (8) is connected to the multi-body burner (7) so that the transfer of combustible gas between both components is possible. The solenoid valve system is normally closed until the electronic controller (10) sends the opening signal when the following conditions of hot water demand and / or water temperature are met: When there is a flow signal and the temperature sensor placed at the outlet of the hot water (12) detects a temperature lower than the maximum cut-off temperature predetermined in the electronic controller (10); or When the temperature detected by both temperature sensors (11 and 12) is lower than a pre-set value in the electronic controller as the minimum ignition temperature.

The electronic controller (10) sends the signal to close the solenoid valve system (8) preventing the passage of gas fuel to the burner when both conditions mentioned above are no longer met.

The temperature sensors placed at the entrance of the cold water (11) and the hot water outlet (12) are introduced in a brass, bronze, or other corrosion resistant material connection, and these in turn, are assembled to the water tank at the entrance of the cold water and at the exit of the hot water respectively.

The two cables that make up each of the temperature sensors (11 and 12) must be in contact with each other at the end that is inside the water tank, the opposite end is connected to the electronic controller (10) as well as the solenoid valve system (8) for fuel gas supply. Beside the temperature sensor to the hot water outlet (12) a bimetallic safety device (13) is located, which will work in the event of overheating in the tank water (2) interrupting the flow of current to the controller electronic (10). This bimetallic safety device allows to suspend the operation of the system in case the temperature in the water exceeds a predetermined value. Thanks to its configuration, the temperature sensors (11 and 12) allow the electronic controller (10) to identify the condition of water demand when there is a difference of 4 ° C between these temperature sensors (11 and 12). Therefore, the water heater (1) will only restart its operation when the temperature in the bimetallic safety device (13) is lower in, for example 4 ° C, with respect to the specified safety temperature.

The electronic controller (10) governs the operation of the different components that make up the water heater, so when receiving a signal of temperature difference greater than, for example 4 ° C, between the temperature sensor at the water outlet hot (12) (Ts) and the cold water inlet temperature sensor (11) (Te) (T3-Te> 4 ° C), sends a direct current signal to the ignition electrode (14) illustrated in figure 4 to generate the electric spark that ignites the burner of several bodies (7).

The ignition electrode (14) is placed at a distance not greater than 4 mm on one of the bodies that make up the burner of several bodies (7). After 3 seconds and with the electric spark in operation, the electronic controller (10) sends a signal to the solenoid valve system (8) for the sequential opening of the solenoid valves that make up said system (8) so as to allow the passage of fuel gas towards the multi-body burner (7). After igniting the multi-body burner (7), the ionization electrode (15) (illustrated in figure 4), placed at a distance no greater than 4 mm on one of the burner bodies of several bodies (7), it will detect the flame through an ionizing process and send the signal to the electronic controller (10).

If the flame signal is not received by the electronic controller (10) in a period of 5 seconds, or if the signal appears intermittently in the same period, or if the multi-body burner (7) goes off in any At this time, the electronic controller (10) sends a signal to the fuel gas supply solenoid valve system (8) for immediate closure and blocks the operation of the water heater (1) for a period of 10 to 15 seconds for the purpose of to allow the dissipation of the gas in the combustion chamber (16) and to carry out an electronic revision of the components connected to the electronic controller (10).

Once the aforementioned 10 to 15 seconds have elapsed, a water heater firing reignition (1) is carried out until a continuous signal of the presence of the flame in the multi-body burner (7) is obtained. If this signal is not detected after three total attempts, the electronic controller (10) will send a signal so that the screen (17) will show an error message, which will indicate that, as a security measure, the system has been temporarily blocked.

Once the flame presence signal has been detected by the electronic controller (10), the water inside the water tank (2) will heat up until the cold water inlet (11), Te, and outlet temperature sensors have been turned on. hot water (12), Ts, send a signal to the electronic controller (10) where it is indicated that the specified temperature has been reached. In turn, the electronic controller (10) sends a signal to close the fuel gas supply solenoid valve system (8).

The ignition cycle will be reactivated until one of the conditions mentioned above is met again.

The electronic controller (10) is electrically powered by a power source (18) which operates by any combination of replaceable batteries, rechargeable batteries or direct connection to a power grid, and which is illustrated in Figure 2. In turn, the Electronic controller (10) will distribute the power supply to the different components to which it is connected.

The water chamber (19) illustrated in figure 4, surrounds the combustion chamber (16) minimizing the losses of thermal energy towards the side parts of the combustion chamber (19), and under it the burner of several bodies (7) and their support (20). The water reservoir (2) on its inner side has a heat exchanger (21) shown in Figure 3, which is formed by a set of fins that allow it to capture most of the thermal energy contained in the gases of combustion to later transfer this energy to the water contained in the water tank (2), managing to transfer to the water in the tank between 80% and 95% of the thermal energy contained in the combustion gases.

In the central part of the heat exchanger (21), there is a core (22) in the form of a cylindrical vessel (see figure 3), whose function is to retard and redirect the combustion gases in their output path forcing them to pass through the fins that make up the heat exchanger (21).

As seen in Figure 3, the external part of the water tank (2) is thermally insulated by the application of an insulator (23) or coating of a material of low thermal conductivity such as polyurethane, mineral wool, ceramic fiber, fiberglass, or any other known in the middle.

The water heater (1) has an outer body of sheet (24) illustrated in figure 2, which is coated with an electrostatic paint resistant to corrosion to improve the aesthetics of the product, in addition to ensuring that the insulator (23) ) remains positioned around the water tank (2) and protect both the insulation (23) and the water tank (2) itself from the effects of the environment.

The outer body of sheet (24) illustrated in Figure 2, has a housing for the electronic controller (10) and at its base has openings, located in the area where the burner of several bodies (7) is located to allow entry of the air necessary for combustion.

In the left lateral part of the outer sheet body (24) the electrovalve system (8) is located together with the power source (18). Both the electrovalve system (8) and the power source (18) are protected from the thermal radiation coming from the multi-body burner (7) by means of a pair of screens (9).

On the other hand, as seen in Figure 5, the electronic controller (10) contains a series of buttons with which the user can operate the heater.

The valve (6) located in the lower right side of the equipment allows the draining and cleaning of the water tank (2).

The air baffle (25) shown in figure 2 prevents the entry of air currents through the upper part of the heater, thus avoiding possible flash backs, and even the extinction of the flame in the burner of several bodies.

The water heater (1) does not operate for most of the time, unless any of the aforementioned ignition conditions are met. This leads to a reduction in the consumption of fuel gas and consequently in the emission of polluting gases into the environment.

Claims

1. A step-by-step water heater of the quick recovery type comprising: A burner with several bodies and a system of electrovalves that regulate the gas flow to said burner safely. An electronic controller that governs the operation of the different components that make up the water heater; A bimetal safety device that allows to suspend the operation of the system in case the temperature of the water in the tank exceeds a predetermined value. An ignition electrode that generates a spark for the ignition of the burner of several bodies and an ionization electrode that detects the ignition of the burner by means of the ionization phenomenon. A power source that works by any combination of replaceable batteries, rechargeable batteries or direct connection to a power grid. characterized because it has: A water tank resistant to corrosion that has a finned heat exchanger and a core supported in the upper central part of the exchanger, so that the joint configuration of these three components allows retarding the output and redirecting the combustion gases to take between 80% and 95% of its thermal energy; Two temperature sensors placed one at the entrance of the cold water and the other at the outlet of the hot water in a configuration that allows the electronic controller to identify the water demand condition when a difference of 4 ° C appears between said temperature sensors . A water chamber that surrounds the combustion chamber minimizing the thermal energy losses towards the side parts of the combustion chamber. An air deflector device whose configuration prevents the entry of air currents through the upper part of the heater and avoids possible flash backs and even the extinction of the flame in the multi-body burner.

2. The water heater as claimed in clause 1 characterized in that the electronic controller sends the ignition signal under the following conditions: a) When there is a flow signal and the temperature sensor placed at the hot water outlet detects a temperature lower than the maximum cut-off temperature predetermined in the electronic controller. b) It will also turn on when the temperature detected by both sensors is less than a pre-set value in the electronic controller as the minimum ignition temperature.

3. The water heater as claimed in clause 1 characterized in that the electronic controller sends the signal to close the solenoid valve system avoiding the passage of fuel gas to the burner when both conditions mentioned in clause 2 cease to be fulfilled.

4. The water heater as claimed in clause 1 characterized in that, after 3 seconds of Having initiated the sending of the electric spark signal and with said spark still in operation, the electronic controller sends a signal to the solenoid valve system to allow the passage of fuel gas to the burner of several bodies.

5. The water heater as claimed in clause 4, characterized in that if the flame signal is not received by the electronic controller within a period of 5 seconds or if the signal appears intermittently in the same period, or If the multi-body burner goes out at any time, the electronic controller sends a signal to the fuel gas supply solenoid valve system for immediate shutdown and blocks the operation of the water heater.