Burner

Abstract

A burner has a combustion head, an ignition device, a fuel delivery/regulating device, a combustion air delivery/regulating device, a safe operation monitoring device, and an electronic control device. The combustion air delivery/regulating device has an air flap mechanism controlled by an air flap actuator, and an inverter for controlling the rotation speed of a blower motor, and has a displacement sensor, linked with the air flap actuator and for controlling the output frequency of the inverter. A program controller of the electronic control device instructs the air flap actuator to control the opening position of the air flap mechanism according to the requirements of a combustion load. The inverter regulates, according to a signal with respect to the opening position of the air flap mechanism and detected by the displacement sensor, the frequency output to the blower motor so as to control the rotation speed of the blower motor.

Description

FIELD OF THE INVENTION

The present invention relates to a combustion equipment, and more particularly relates to a burner.

BACKGROUND OF THE INVENTION

Burners are commonly used in heat exchange equipments, such as boilers, heating, ventilating, and air conditioning (HVAC) equipments and so on, and direct heating equipments such as drying machines, heat treatment devices and so on. Burners are electro-mechanical products with high degree of automation. A burner is mainly composed of a combustion head, an ignition device, a fuel delivery/regulating device, a combustion air delivery/regulating device, a safety operation monitoring device and a control device and so on. Wherein, the function of the combustion air delivery/regulating device is to blow sufficient air into the combustion head, so as to meet the air requirement for combustion of the fuel (such as fuel gas or fuel oil). The conventional burner is equipped with a blower which is running at constant speed, thus, when firing at low load, the motor of the blower is still running at constant speed, thereby wasting motor power.

There is a design of burner which is equipped with an inverter in its blower to control the speed of the motor. For example, an utility model patent granted by SIPO on Jun. 30, 2004, patent number ZL03243710.3, discloses a frequency conversion automatic blowing type gas burner, which is equipped with an inverter. The inverter is connected to a program controller of the control device and the blower motor. According to the change of load of the boiler, the program controller controls the output frequency of the inverter, thereby controlling the operating frequency of the motor, so as to realize an accurate regulation of the blowing rate and achieve an objective of increasing burning efficiency and energy conservation.

However, this burner, which only uses an inverter to achieve speed control, has a defect that its combustion output regulating range is quite narrow. FIG. 1, shows a typical operating curve of this burner, when the blower is running at high rotation speed (n₁), the value of ΔP1 is higher, and with the decrease of rotation speed of the blower, the value of ΔP will gradually reduce, that is, A P1>ΔP2>ΔP3> . . . >ΔPn, if the value of ΔP reduces to certain low value, it will lose the adaptive ability with regard to the flame, and causing instability of the flame. In general, the combustion output regulating range of this burner, which only uses an inverter to achieve speed control, is about 2:1, that is, the output of high flame is 100%, and the output of low flame is 50%.

SUMMARY OF THE INVENTION

The present invention is to provide a burner with wider combustion output regulating range, so as to solve a technical problem that the existing burner has a narrower combustion output regulating range.

To solve the above-mentioned technical problem, the present invention uses the following technical solution: a burner, which includes a combustion head, an ignition device, a fuel delivery/regulating device, a combustion air delivery/regulating device, a safety operation monitoring device, and a control device. The combustion air delivery/regulating device includes a shell casing, a blower impeller fitted in the shell casing, a blower motor linked with the blower impeller for rotating the blower impeller, an air flap mechanism fitted to the shell casing, an air flap actuator linked with an air flap baffle of the air flap mechanism to control the opening position of the air flap mechanism, a displacement sensor for detecting the opening position of the air flap mechanism and an inverter respectively wired to the blower motor and the displacement sensor, wherein, the shell casing is connected to the combustion head via an air duct, the air flap actuator is wired to a program controller of the control device and is controlled to operate by the program controller, the program controller outputs a signal to the air flap actuator to control the opening position of the air flap mechanism according to the requirement of a combustion load, the displacement sensor outputs a detected signal with respect to the opening position of the air flap mechanism to the inverter, and the inverter accordingly regulate the frequency output to the blower motor.

In the above-mentioned burner, the program controller is wired to a firepower regulating controller, the firepower regulating controller is wired to a temperature/pressure sensor installed at a thermal device, the sensor detects the temperature/pressure of the thermal device, the temperature/pressure signal is fed back to the firepower regulating controller and accordingly calculates the opening position of the air flap mechanism and transfers to the program controller to execute the control the air flap actuator.

In the above-mentioned burner, a fuel regulating valve fitted at the fuel delivery/regulating device is an air/fuel ratio fuel regulating valve, which has an air pressure detecting tube to detect the air pressure in the air duct of the combustion air delivery/regulating device and accordingly regulates the opening position of the fuel regulating valve, so as to control the flow of the fuel.

In the above-mentioned burner, the fuel regulating valve has a servo stabilizer fitted therein, which has a fuel pressure detecting tube to detect the fuel pressure at the outlet of the fuel regulating valve, and accordingly regulates the opening position of the fuel regulating valve, in order to maintain a stable pressure at the outlet of the fuel regulating valve.

In the above-mentioned burner, the displacement sensor is installed at the air flap actuator.

In the above-mentioned burner, the displacement sensor is installed at the air flap mechanism.

In the above-mentioned burner, the displacement sensor is a potentiometer.

In the above-mentioned burner, the potentiometer is either a rotating type or a sliding-type potentiometer.

In the above-mentioned burner, the inverter is connected to the program controller which controls the start/stop of the inverter.

The beneficial technical effect of the present invention is: the blower device of the burner is fitted with an air flap mechanism controlled by an air flap actuator, and an inverter for controlling the rotation speed of a blower motor, and a displacement sensor, linked to the air flap actuator is for controlling the output frequency of the inverter. A program controller of the control device instructs the air flap actuator to control the opening position of the air flap mechanism according to the requirements of a combustion load. The inverter regulates the frequency output to the blower motor so as to control the rotation speed of the blower motor according to a signal with respect to the opening position of the air flap mechanism as detected by the displacement sensor. Thus, by combining the speed control achieved by changing the frequency and the opening position of the air flap, the burner output regulating range can be extended wider.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an operating curve of an existing burner which uses an inverter to achieve speed control;

FIG. 2 is a structure diagram of the burner of the present invention;

FIG. 3 is a partial structure diagram of the burner of the present invention;

FIG. 4 is a structure diagram of partial control circuit of the burner of the present invention;

FIG. 5 is a structure diagram of another partial control circuit of the burner of the present invention;

FIG. 6 is a schematic diagram of inverter setting of the burner of the present invention;

FIG. 7 is an operating curve of the burner of the present invention when using an inverter to achieve speed control and using a blower inlet-type air flap regulation;

FIG. 8 is an operating curve of the burner of the present invention when using an inverter to achieve speed control and using a blower outlet-type air flap regulation.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The following illustration together with the accompanying drawings and embodiments will facilitate an ordinary skilled person to have a clear understanding of the objective, technical solution and advantages of the present invention.

Referring to FIG. 2 to FIG. 5, the burner disclosed by the present invention includes a combustion head 10, an ignition device (not shown in the figures), a fuel delivery/regulating device 12, a combustion air delivery/regulating device 14, a safety operation monitoring device (not shown in the figures), and a control device 16. The control device 16 is respectively connected to the ignition device and the fuel delivery/regulating device 12, the blower device 14 and the safety operation monitoring device to control the operation of each above-mentioned device, thereby completing the automated operation of the burner.

The combustion head 10 includes a flame tube 100 and a nozzle 101 fitted in the flame tube 100. The nozzle 101 is connected with the fuel delivery/regulating device 12 via a fuel pipe 120, and the fuel (fuel gas or fuel oil) will be delivered to the nozzle 101 by the fuel delivery/regulating device 12 and then carry out combustion. Generally, a flame stabilizer 102 is fitted at a position corresponding to the nozzle 101; the flame stabilizer 102 can be fitted in the front of the nozzle 101 and also can be fitted behind the nozzle 101.

The ignition device includes an ignition electrode(s) fitted adjacent to the nozzle 101, and the ignition electrode(s) is wired to the program controller 160 of the control device 16 via an ignition transformer Al.

As shown in FIG. 5, the fuel delivery/regulating device 12 includes a fuel pipe 120 and a fuel regulating valve 121 fitted at the fuel pipe 120, and includes a control valve A2, a safety valve A3, a pilot valve A4, a low fuel pressure protection unit A5, a high fuel pressure protection unit A6 and a fuel valve leakage detecting unit A7 and so on, all of which are controlled by the program controller 160. Certainly, the fuel delivery/regulating device 12 is not limited to above-mentioned structure, and it can adopt all kinds of suitable fuel delivery/regulating device 12 of the current technology.

The fuel regulating valve 121 is an air/fuel ratio fuel regulating valve, which has an air pressure detecting tube 122 to detect the air pressure (air quantity) in the air duct 148, and accordingly regulates the opening position of the fuel regulating valve 121, thereby controlling the flow of the fuel. Preferentially, the fuel regulating valve 121 has a servo stabilizer fitted therein, which has a fuel pressure detecting tube 123 to detect the fuel pressure at the outlet of the fuel regulating valve 121, and accordingly regulates the opening position of the fuel regulating valve 121, in order to maintain a stable pressure at the outlet of the fuel regulating valve 121.

The blower device 14 includes a shell casing 140, a blower impeller 141 fitted in the shell casing 140, a blower motor 142 linked with the blower impeller 141 for rotating the blower impeller 141, an air flap mechanism 143 fitted at the shell casing 140, an air flap actuator 145 linked to an air flap baffle 144 of the air flap mechanism 143 to control the opening position of the air flap mechanism 143, a displacement sensor 146 for detecting the opening position of the air flap mechanism 143 and an inverter 147 respectively wired to the blower motor 142 and the displacement sensor 146. Wherein, the air flap actuator 145 is wired to the program controller 160 of the control device 16 and is controlled to operate by the program controller 160; the inverter 147 is wired to the program controller 160 and the start/stop of the inverter 147 is controlled by the program controller 160; while the shell casing 140 is connected to a flame tube 100 of the combustion head 10 via an air duct 148. The program controller 160 outputs a signal to the air flap actuator 145 to control the opening position of the air flap mechanism 143 according to the requirements of a combustion load, the displacement sensor 146 outputs a detected signal with respect to the opening position of the air flap mechanism 143 to the inverter 147, and the inverter 147 accordingly regulates the frequency output to the blower motor 142, thereby controlling the rotation speed of the blower motor.

In the above-mentioned embodiment, the displacement sensor 146 is linked to the air flap actuator 145, so as to detecting the opening position of the air flap mechanism 143. Obviously, the displacement sensor 146 also can be linked to the air flap mechanism 143 (for example, linked to the spindle of the air flap baffle), which also can detect the opening position of the air flap mechanism 143.

Preferably, the displacement sensor 146 is a rotating-type or sliding-type potentiometer, and the air flap mechanism 143 is linked to the potentiometer. When the air flap actuator 145 regulates the opening position of the air flap mechanism 143, the potentiometer outputs different resistances according the travel of its own rotation angle (or slide distance), served as a control input to the inverter 147.

The program controller 160 is wired to a firepower regulating controller 150, the firepower regulating controller 150 is wired to a temperature/pressure sensor 151 fitted at a thermal device (includes heat exchange device or heating device), the sensor detects the temperature/pressure of the thermal device, the temperature/pressure signal detected is fed back to the firepower regulating controller 150 and accordingly calculates the opening position of the air flap mechanism 143 and transfers to the program controller 160 to execute the control of the air flap actuator 145.

The safety operation monitoring device mainly includes a flame monitor, which is used for monitoring the condition of the combustion flame and producing fed back signal to the program controller 160.

Referring to FIG. 6, the inverter 147 is provided with a minimum output frequency and a maximum output frequency settings. Between the minimum output frequency and the maximum output frequency settings, its output frequency towards the blower motor 142 is regulated correspondingly to the signal of the displacement sensor 146. Referring to FIG. 6, using a potentiometer as an example, between the minimum and maximum output frequency settings, the output frequency of the inverter 147 is regulated correspondingly to the change of the resistance value of the potentiometer. Certainly, the value illustrated in the FIG. 6, such as the resistance value of the potentiometer, the opening position of the air flap mechanism 143, the output frequency of the inverter 147, is merely one possible embodiment, but not used for limiting the present invention.

Now take a potentiometer as a displacement sensor for example to illustrate the operation of the burner disclosed by the present invention, which mainly includes the following stages.

1. Stand by stage: the contacts of the automatic control loop are separated; the fuel supply is cut off; the blower device 14 stops running; the air flap mechanism 143 in closed position; and waiting for the startup instruction.

2. Start up stage: the contacts of the automatic control loop are closed; the burner begins to carry out a series of safety check programs; and a pre-purging program can be started after the system safety check is confirmed.

3. Pre-purging stage: the air flap actuator 145 rotates forward (or moves forward) and opens the air flap mechanism 143 at low speed; simultaneously, the blower motor 142 starts up and begins to rotate at low speed; during the air flap mechanism 143 opening, the resistance output of the potentiometer changes; when the resistance output of the potentiometer exceeds the minimum setting of the inverter 147, the inverter 147 will increase the output frequency according to the input resistance, and the blower motor 142 will increase the rotate speed indirectly to follow the opening position of the air flap mechanism 143; when the resistance output of the potentiometer exceeds the maximum input setting of the inverter 147, the blower motor 142 stops speeding up and continues to rotate at high speed until the pre-purging stage is completed.

4. Ignition stage: at the end of the pre-purging stage, the air flap actuator 145 rotates in the opposite direction (or moves backward) to close the air flap mechanism 143 at low speed; simultaneously, the blower motor 142 reduces the rotating speed (corresponding to the output of the potentiometer), the air flap mechanism 143 stops at a preset ignition position (or angle), at this time, the blower motor 142 is running at minimum rotating speed, ready for the ignition of start flame; the ignition electrode(s) is electrified to produce arc discharge, then the pilot valve A4 is opened and allows little fuel to enter into the combustion head 10 for ignition of the start flame, after the start flame is ignited and confirmed, the fuel regulating valve 121 is opened to allow the fuel to enter into the combustion head 10 for ignition of the main flame; after the main flame is firing normally and the flame safety check is confirmed, the pilot valve A4 is cut off, at this time, the burner is firing at low flame, the ignition stage is completed.

5. Normal combustion and load regulating stage: at the normal combustion stage, the adjustment of opening position of the air flap mechanism 143 is controlled by the firepower regulating controller 150; the air flap actuator 145 regulates the opening position of the air flap mechanism 143 according the load; the resistance variation of the potentiometer (linked with the air flap mechanism 143) controls the output of the inverter 147; the rotating speed of the blower motor 142 is indirectly controlled by the air flap actuator 145; since the fuel regulating valve 121 is an air/fuel ratio fuel regulating valve, the air pressure of the air duct 148 automatically controls the opening position of the fuel regulating valve 121, thereby increasing/reducing the input of fuels.

6. Post-purging stage: when the contacts of automatic control loop are separated, the program controller 160 cuts off the fuel valves and stops fuel supply. The burner begins the post-purging stage; the air flap actuator 145 rotates forward (or moves forward) and drives the air flap mechanism 143 to open wider, the blower motor 142 is running at a higher speed to increase the purging air quantity. If the thermal equipment needn't execute a post-purging program, the blast purging program of this stage will be skipped.

7. Stop running (return to stand by) stage: after finishing (or skipping) the post-purging stage, the inverter 147 stops operation (the blower motor 142 stops running), the air flap mechanism 143 executes a rotation in opposite direction (or moves backward) to drive the air flap mechanism down until the air flap mechanism moves to a preset closed position (or angle). The burner is in a stand by stage waiting for a next start up instruction.

The blower device 14 of the present invention has an air flap mechanism 143 controlled by an air flap actuator 145, and an inverter 147 for controlling the rotation speed of a blower motor 142, and has a displacement sensor 146, linked with the air flap actuator 145 and for controlling the output frequency of the inverter 147. The program controller 160 instructs the air flap actuator 145 to control the opening position of the air flap mechanism 143 according to the requirements of a combustion load. According to a signal with respect to the opening position of the air flap mechanism 143 as detected by the displacement sensor 146, the inverter 147 regulates the frequency output to the blower motor 142 so as to control the rotation speed of the blower motor 142. Thus, by combining the speed control achieved by changing the frequency and the adjustment of the air flap mechanism, the firepower regulating range of the burner can be extended. For example, FIG. 7 shows an operating curve of the burner when using an inverter to achieve speed control and combining a blower inlet-type air flap mechanism regulation, and FIG. 8 shows an operating curve of the burner when using an inverter to achieve speed control and combining a blower outlet-type air flap mechanism regulation. It can be seen from the figures that, by a way of combining the adjustment of the air flap mechanism and the speed control achieved by changing the frequency, when the combustion load is higher, it can be achieved by using higher frequency output of the inverter cooperated with the adjustment of bigger opening position of the air flap mechanism, when the combustion load is lower, it can be achieved by using lower frequency output of the inverter cooperated with the adjustment of smaller opening position of the air flap mechanism, thereby can achieve the firepower regulating range of 5:1 or even wider.

While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments. For example, all of the combustion head, the ignition device, the fuel delivery/regulating device, the safety operation monitoring device and the control device of the burner can adopt suitable structures of the current technology. Any equivalent arrangements or modifications included within the scope of claims should be included within the scope of protection of the invention.

Claims

1. A burner comprising a combustion head (10), an ignition device, a fuel delivery/regulating device (12), a combustion air delivery/regulating device (14), a safety operation monitoring device, and a control device (16), wherein the combustion air delivery/regulating device (14) comprises a shell casing (140), a blower impeller (141) fitted in the shell casing (140), a blower motor (142) linked with the blower impeller (141) for rotating the blower impeller (141), an air flap mechanism (143) fitted in the shell casing (140), an air flap actuator (145) linked with an air flap baffle (144) of the air flap mechanism (143) to control the opening position of the air flap mechanism (143), a displacement sensor (146) for detecting the opening position of the air flap mechanism (143) and an inverter (147) respectively wired to the blower motor (142) and the displacement sensor (146); wherein, the shell casing (140) is connected to the combustion head (10) via an air duct (148), the air flap actuator (145) is wired to a program controller (160) of the control device (16) and is controlled to operate by the program controller (160), the program controller (160) outputs a signal to the air flap actuator (145) to control the opening position of the air flap mechanism (143) according to the requirements of a combustion load, the displacement sensor (146) outputs a detected signal with respect to the opening position of the air flap mechanism (143) to the inverter (147), and the inverter (147) accordingly regulates the frequency output to the blower motor (142); and the program controller (160) is wired to a firepower regulating controller (150), the firepower regulating controller (150) is wired to a temperature/pressure sensor (151) installed at a thermal device to detects the temperature/pressure of the thermal device, the detected is fed back to the firepower regulating controller (150) and accordingly calculates the opening position of the air flap mechanism (143) and transfer to the program controller (160) to drive the air flap actuator (145).

2. (canceled)

3. The burner according to claim 1, wherein a fuel regulating valve (121) installed at the fuel delivery/regulating device is an air/fuel ratio fuel regulating valve, which has an air pressure detecting tube to detect the air pressure in the air duct (148) of the combustion air delivery/regulating device (14) and accordingly regulates the opening position of the fuel regulating valve (121), so as to control the flow of the fuels.

4. The burner according to claim 3, wherein the fuel regulating valve (121) has a servo stabilizer fitted therein, which has a fuel pressure detecting tube (123) to detect the fuel pressure at the outlet of the fuel regulating valve (121), and accordingly regulates the opening position of the fuel regulating valve (121), in order to maintain a stable pressure at the outlet of the fuel regulating valve.

5. The burner according to claim 1, wherein the displacement sensor (146) is installed at the air flap actuator (145).

6. The burner according to claim 1, wherein the displacement sensor (146) is installed at the air flap mechanism (143).

7. The burner according to claim 1, wherein the displacement sensor (146) is a potentiometer.

8. The burner according to claim 7, wherein the potentiometer is a rotating-type or sliding-type potentiometer.

9. The burner according to claim 1, wherein the inverter (147) is wired to the program controller (160) which controls the start/stop of the inverter (147).