EP1712841A1

EP1712841A1 - Electronic device and method for managing the exhaust of burnt gases, in particular in a boiler

Info

Publication number: EP1712841A1
Application number: EP05425224A
Authority: EP
Inventors: Claudio Bianchini; Daniele Vecchi; Alberto Benecchi
Original assignee: Immergas SpA
Current assignee: Immergas SpA
Priority date: 2005-04-14
Filing date: 2005-04-14
Publication date: 2006-10-18

Abstract

Electronic device (1) for managing the exhaust of burnt gases, particularly in a boiler comprising an exhaust duct for burnt gases and ventilation devices (3) together with said exhaust duct for the ejection of the gases. The device (1) originally comprises a processing unit (2) functionally connected to the ventilation devices (3) in order to manage their operation and a pressure sensor (4) for detecting an exhaust pressure of the burnt gases. The sensor (4) is feedback-connected to the processing unit (2). Method for managing the exhaust of burnt gases, particularly in a boiler.

Description

The invention described herein concerns an electronic device and method for managing the exhaust of burnt gases, particularly in a boiler.
Boilers currently available on the market need mechanical diaphragms to operate at the appropriate working pressure, these diaphragms being able to change the length and/or cross section of the fume vent so that the boiler can operate at the appropriate working pressure.
As a matter of fact, if the pressure of the burnt gases inside the exhaust duct of the boiler dropped below a minimum value, it would not be possible to ensure the ejection of the gases thereof. As a result of this, if the value of the pressure is too low, the flue located upstream of the exhaust duct would clog up due to, for example, soot and/or particulate deposits produced by the combustion processes.
The aforesaid diaphragms are basically spacers and/or throttling rings with a variable length, shape and cross section. In particular, they can be rigid or flexible sleeves with a circular, square, rectangular section or other shape.
These diaphragms are currently the only devices able to adapt the boiler fume vent to that presently existing in a building's structure.
The disadvantage of the above and briefly mentioned diaphragms lies in the fact that they must be installed during the installation of the boiler. This is particularly unfavorable, inasmuch as the installers do not always install the diaphragms in the fume vent, usually because of the difficulty of the operation or simply because they need to complete the job hurriedly.
Not installing the diaphragms will compromise both the safety of the boiler and the end user's comfort.
As a matter of fact, the absence of diaphragms could have a negative effect upon the value of the outflow pressure of the burnt gases which could release gas into the environment as well as compromise the effectiveness of the flue draft.
Moreover, the absence of diaphragms could cause bothersome noises inside the boiler due to the oscillation of air and burnt gases masses caused by resonance phenomena induced by incorrect cross sections or length of the fume vent.
Another disadvantage of mechanical diaphragms consists in the difficulty in replacing them when, for any eventuality, it is necessary to change the length of the fume vent, e.g. due to the installation of a fan provided with additional power to suck and eject burnt gases from the burner.
Another problem consists in the need to install appropriate diaphragms for each type of boiler, which gives rise to considerable production costs as well as warehousing problems.
The scope of the invention described herein is to eliminate the above drawbacks by using an electronic device for the management of burnt gases, particularly in a boiler, thereby avoiding the need to install mechanical diaphragms.
Another scope of the invention described herein is to build an electronic device for the management of burnt gases able to adapt and connect the boiler fume vent to that of a building without interposing mechanical spacers, for example the above-mentioned diaphragms.
Another scope of the invention described herein consists in the use of an electronic device for the management of burnt gases, which can be extremely easy to install and basically universal, in other words compatible with many types of boilers.
Another scope consists in achieving the above-mentioned results in the light of a simple, functional and reliable structural solution.
The scopes of the invention described herein can be fully achieved by the electronic device and method for the management of the exhaust of burnt gases, particularly in a boiler, which are characterized according to the claims specified below.
These and other scopes, according to a merely illustrative and not limitative preferred embodiment, will be better pointed out in the following description according to the attached drawing wherein the sole figure describes a functional scheme of an electronic device for the management of burnt gases, particularly in a boiler, according to the present invention.
With reference to figure 1, the electronic device for managing the exhaust of burnt gases is entirely indicated by the number "1".
The device 1 is particularly suitable for being installed in boilers equipped with an exhaust duct for burnt gases and provided with ventilation devices, normally located near an inlet to said duct, capable of ejecting burnt gases coming from the burner.
With a new and original approach, the device 1 comprises a processing unit 2, which is functionally connected to ventilation devices 3 in order to manage their operation.
The device 1 comprises a pressure sensor 4 capable of detecting an exhaust pressure of the burnt gases. In particular, the sensor 4 is advantageously feedback-connected to the processing unit 2.
More precisely, the device 1 has an operation scheme referred to as "closed ring" instead of a more simple, but definitely imprecise and unreliable, operation scheme referred to as "open ring".
In the preferred and illustrated embodiment, the device 1 has at least one actuator 5 functionally connected to the processing unit 2 in order to control the ventilation devices according to a signal coming from the unit thereof.
In traditional boilers, ventilation devices generally comprise a fan, usually of the centrifuge type.
As shown in the example, the processing unit 2 comprises a programmable functional block 6 capable of generating a signal A for managing the operation of the ventilation devices 3. In particular, such functional block 6 preferably comprises software containing the characteristic operation curve for the ventilation devices 3, in order to control their operational parameters according to a thermal input request signal P on the part of a user.
The processing unit 2 also comprises electronic devices 7 capable of making a comparison between a signal A generated by the functional block 6, and a ranging signal B coming from the pressure sensor 4. In particular, the electronic devices generate a control signal C to be sent to the actuator 5 in order to operate the ventilation devices 3.
In a possible embodiment, such electronic devices 7 comprise at least one adder circuit.
More precisely, the control signal C forces the actuator 5 to change the rotating speed of the fan.
In the illustrated embodiment, the device 1 preferably comprises a second actuator 8 used for controlling, via an electric signal D, a rate modulator 9 for fuel gas to be fed to the boiler burner.
The procedure for managing the exhaust of burnt gases, particularly in a boiler, according to the present invention, originally comprises the following phases:

measurement of an exhaust pressure of the burnt gases;
comparison between the measured pressure value and the preset operation parameters of the ventilation devices functionally associated with an exhaust duct of the burnt gases;
generation of a control signal starting from said comparison phase;
variation of an operating speed of said ventilation devices, according to the generated control signal.

In particular, the phase concerning the variation of the operating speed of the ventilation devices occurs thanks to at least one electric actuator operated by at least one processing unit capable of making a comparison between said measured pressure value and said preset operation parameters of the ventilation devices.
The operation of the electronic device for managing the discharge of burnt gases is as follows:

A power request signal P is received by the device 1 and redirected both to the processing unit 2 and to the control actuator 8 of the fuel gas rate modulator 9.

The functional block 6 generates a signal A for managing the operation of the ventilation devices 3, according to the power value requested and/or set by a user.
The electronic devices 7 compare signal A with signal B coming from the pressure sensor 4 in order to generate a control signal C to be sent to the actuator 5 and to change the operating speed of the ventilation devices.
The invention achieves significant advantages.
Firstly, an electronic device, according to the present invention, ensures suitable exhaust pressure of the burnt gases, thereby avoiding the installation of mechanical diaphragms.
Secondly, by constantly monitoring the exhaust pressure of the burnt gases, such device does not require the installation of a minimum-pressure safety valve. Boilers are usually equipped with a safety valve capable of shutting down the burner in case the exhaust pressure of the burnt gases drops below a minimum value; as a matter of fact, this is an indication of a possible blockage in the exhaust ducts with an apparent danger of overpressures inside the burner.
Another advantage is given by the fact that a device according to the invention is extremely easy to install and can be applied to many types of boilers, whether they are new or already operating.
A device according to the invention is advantageously inexpensive and easy to build.

Claims

Electronic device (1) for managing the discharge of burnt gases, particularly in a boiler, comprising:
at least one exhaust duct for the burnt gases;

ventilation devices (3) together with said exhaust duct for the ejection of gases,

characterized in that it comprises:
at least one processing unit (2) functionally connected to the ventilation devices (3) in order to manage their operation;

at least one pressure sensor (4) capable of detecting an exhaust pressure of the burnt gases, said sensor (4) being feedback-connected to the processing unit (2).
Device according to claim 1, characterized in that it comprises at least one actuator (5) functionally connected to the processing unit (2) in order to control the ventilation devices (3) according to a signal (C) coming from the unit (2) thereof.
Device according to claim 1, characterized in that the processing unit (2) comprises:
at least a programmable functional block (6) capable of generating a signal (A) for managing the operation of the ventilation devices (3);

electronic devices (7) capable of making a comparison between THE signal (A) generated by said functional block (6) and a ranging signal (B) coming from the pressure sensor (4), said electronic devices (7) generating a control signal (C) of the ventilation devices (3).
Device according to claim 3, characterized in that the ventilation devices (3) comprise at least one fan.
Device according to claim 4, characterized in that the ventilation devices (7) are capable of generating a control signal (C) able to change the rotating speed of the fan.
Device according to claim 1, characterized in that it comprises at least a second actuator (8) for controlling a rate modulator (9) for fuel gas to be fed to the boiler burner.
Method for managing the exhaust of burnt gases, particularly in a boiler, characterized in that it comprises the following phases:
measurement of an exhaust pressure of the burnt gases;

comparison between the measured pressure value and the preset operation parameters of the ventilation devices functionally associated with an exhaust duct of the burnt gases;

generation of a control signal starting from said comparison phase;

variation of an operating speed of said ventilation devices, according to the generated control signal.
Method according to claim 7, characterized in that the phase concerning the variation of an operating speed of the ventilation devices occurs thanks to at least one electric actuator operated by at least one processing unit capable of making a comparison between said measured pressure value and said preset operation parameters of the ventilation devices.
Boiler, characterized in that it comprises a device according to any of the previous claims, from 1 to 6, and/or the implementation of a method according to any of the previous claims 7 or 8.