JP6525569B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus in which the amount of air supplied is changed by a damper according to each process, and more specifically, energization of a damper control circuit by a limit switch operated by a cam provided in the damper device. The present invention relates to a combustion apparatus that switches paths and controls damper operation and creates a damper position signal.

As described in JP-A-2008-51391, in a combustion apparatus in a boiler or the like, the supply of combustion air by a blower is widely performed. In the combustion apparatus in which the amount of air supplied is different in each process such as high combustion process, medium combustion process, low combustion process and ignition process, damper vanes and damper vanes provided in the middle of the air passage connecting the burner unit and the blower A damper device having a damper control motor to rotate is provided, and the amount of air supplied is adjusted by the damper device. In the damper device, the flow passage area of the air flow passage is changed by changing the position of the damper blade, and the air supply amount to the burner unit is adjusted. If the air volume to be supplied is an ignition volume, a low combustion volume, a medium combustion volume, a high combustion volume, the opening degree of the damper is set to four stages according to each process, and the damper control motor The position of the damper blade is changed at to adjust the air supply amount.

A limit switch is used to detect the damper position. 7 to 9 describe the operation of the limit switch. In the limit switch, the switch is switched depending on the position of the cam installed on the axis of the damper. The limit switch changes from ON to OFF or from OFF to ON depending on whether the cam is pressed or not, switches the path through which current in the damper control circuit flows with the limit switch, and controls the damper operation, and The position of the damper is detected by a signal that changes as the current path is switched. FIG. 7 shows the state of the limit switch in the case where there is pressure by the cam, and since the switch is in contact with the lower contact, a current flows in the lower contact. FIG. 8 shows the state of the limit switch in the case where there is no pressing by the cam, and since the switch is in contact with the upper contact, current flows in the upper contact. The operating part of the limit switch is a spring, and if the limit switch is normal, it is connected to either the a contact or the b contact, but with the limit switch, it is rarely at an intermediate position between the a contact and the b contact. Due to the occurrence of the staying phenomenon and the inability to confirm the position, the damper may become abnormal. This phenomenon is also referred to as a micro operating characteristic, and as described in FIG. 9, when the terminal of the limit switch stops at an intermediate position between the a contact and the b contact, either the a contact or the b contact The current does not flow beyond the limit switch because it does not touch either. The damper control circuit creates a damper position signal from the flow path of the current switched by the limit switch, and confirms the damper position when the correct damper position signal can not be created due to the occurrence of the minute operation characteristic of the limit switch. Can not

In addition, the fine operation characteristic with the limit switch occurs only rarely and recovers immediately if it occurs. Then, even if detection of the damper position can not be performed due to the occurrence of the fine operation characteristic, the damper position is the stationary damper if it is stopped when the limit switch becomes the fine operation characteristic and the contact is separated. It will be the correct position. However, even if the damper position is at the correct position, if the controller does not confirm that it is at the correct position, the damper is determined to be abnormal, so the combustion device forcibly stops the operation due to an abnormality occurrence. It will be done.

JP, 2008-51391, A

  The problem to be solved by the present invention is that, in a combustion apparatus having a damper device for stepwise changing the air supply amount for combustion, only the damper position can not be detected temporarily due to the fine operation characteristic of the limit switch. When the damper is operating normally, it does not cause an abnormality that forcibly stops the operation, and when an abnormality occurs in which a break occurs in the control circuit and the damper does not operate, An object of the present invention is to provide a boiler having a damper control device which can be distinguished and detected as a necessary abnormality to be dealt with.

A combustion apparatus comprising a burner unit, a blower for supplying air to the burner unit, and an operation control device for changing an air supply amount according to a process of operation , comprising a damper control motor and a damper blade , damper for controlling the energization of the damper control motor based damper device for regulating the amount of air supplied to the burner unit by driving the damper blade in the damper control motor, the command for the operation control device outputs and a control circuit, wherein a limit switch to detect the position of the damper blade to switch the current path in the damper control circuit, the operation control of the damper position information created from the status of the current path in the damper control circuit in the combustion apparatus having a connector for sending to the device, the damper control circuit, current supply to the damper control motor Detecting the energized state at a position where such is always voltage, the energization state detects a change to OFF from ON, and out of the damper position information, wherein the limit switch, halfway between the contacts by fine operating characteristics If the phenomenon of stop in the position it was confirmed to be normal in the portion except the portion where erroneous signals that could be created if occurs, not a state in which the damper position information is intended also, the combustion device comprising a go a performed determination of the damper position is abnormal.

By carrying out the present invention, it is not an abnormality accompanied by the stop of the combustion when the damper position can not be detected temporarily due to the fine operation characteristic of the limit switch, so that the unnecessary stop of the combustion can be prevented. it can. In addition, when a break occurs in the control circuit and the damper does not operate, it is detected as a necessary abnormality in combustion stop, so the abnormality is in spite of the damper not operating. Can be prevented from being overlooked.

Combustion device composition outline figure in one example of the present invention The time chart which described the change circumstance of damper opening in one execution example of this invention Explanatory drawing which described the flow of control information at the time of damper control in one example of the present invention Explanatory drawing which showed the flow of the electric current during damper position movement in the damper control circuit of one Example of this invention Explanatory drawing which showed the flow of the electric current at the time of damper position movement completion in the damper control circuit of one Example of this invention Explanatory drawing which showed the flow of the electric current at the time of a micro operation characteristic generate | occur | producing in the limit switch in the damper control circuit of one Example of this invention Operation of the limit switch when holding down with a cam Operation state of limit switch when not pressed down by cam Operation state of limit switch when fine operation characteristics are generated Switch ON / OFF status list when moving from the ignition position to the low combustion position in the damper control circuit of one embodiment of the present invention

  One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a combustion apparatus according to an embodiment of the present invention, FIG. 2 is a time chart describing the change in the opening degree of the damper according to an embodiment of the present invention, and FIG. 4 to 6 are damper control circuit explanatory views showing the flow of current in one embodiment, FIGS. 7 to 9 are operation status explanatory views of limit switches, and FIG. 10 is a damper control circuit. It is a list of ON / OFF states of a switch.

First, FIG. 1 will be described. The combustion apparatus 1 of the present embodiment is a boiler, and a burner is provided at the upper part of the boiler main body, and combustion is performed by supplying fuel and air to the burner. The supply of combustion air to the combustion apparatus is performed by operating the blower 3, and the burner unit and the blower 3 are connected by the blower path 6. In the middle of the air flow path 6, the damper apparatus 4 which changes the flow area in the air flow path 6 with a damper blade | wing is provided. The damper device 4 changes the flow passage area of the air flow passage 6 by rotationally driving the damper blade portion with a damper control motor, and adjusts the amount of combustion air supplied by changing the flow passage area. The adjustment of the fuel supply amount is performed by the fuel supply amount control device provided in the fuel supply path. The operation control device 7 connected to the blower 3, the damper device 4, and the fuel supply amount control device is provided, and the operation control of each part is performed by the operation control device 7. The damper control circuit 2 is installed in the operation control device 7, and the operation of the damper control motor and the detection of the damper position are performed by the damper control circuit 2.

The combustion device controls combustion at three positions, high combustion, low combustion, and stop, and performs ignition in a state where the amount of air is squeezed, and in the order of low combustion and high combustion, the fuel supply amount and the combustion air amount Increase the amount of combustion by increasing it. The damper device 4 sets a high combustion position, a low combustion position, and an ignition position between the fully closed position and the fully open position. The operation of the damper device 4 is performed by the damper control circuit 2 in the operation control device 7. When the damper control circuit 2 outputs a damper position command from the operation control device 7, the relay in the damper control circuit operates, and the energization path in the damper control circuit changes. When current is supplied to the damper control motor, the damper control motor operates to move the position of the damper blade. The damper control motor operates in two directions, the damper opening direction and the damper closing direction, and also enables operation in the opposite direction by the flow path of the current flowing in the damper control circuit. The position of the damper blade is about 90 degrees from the fully closed position to the fully open position, and the supply amount of combustion air is adjusted by stopping at a position for each combustion amount set in advance.

The fully closed position is a position where the damper blade is perpendicular to the air flow direction in the air passage 6, and the air supply amount is increased by increasing the opening degree in the order of the ignition position, low combustion position and high combustion position. Will increase. The damper control circuit 2 is configured to rotate a blade provided in the air passage 6 by a damper control motor (DCM). A plurality of cams are provided on the damper shaft, and the cam rotating with the damper shaft turns the limit switch ON / OFF, and the position of the damper is detected by the current path in the circuit switched by the limit switch.

The operation of the limit switch according to the damper position is performed at the high combustion position (cm1), the low combustion position (cm2), and the ignition position (cm3). A cam is installed corresponding to the position of the damper, and each limit switch outputs ON (a contact side) when the damper is opened from the set position, and outputs OFF (contact b) when closed. The action of the limit switch changes the flow path of the current flowing in the damper control circuit, and when energization to the damper control motor is performed, the damper blade is driven and when energization to the damper control motor is stopped, the damper blade is driven Stop. Further, the operation control device 7 detects the position of the damper based on a signal input from the damper control circuit 2. The terminals CN-1 to CN-6 are set in the connector CN having a plurality of terminals in the damper control circuit, and CN-1 to CN-3 among these are for transmitting damper position information . The operation control device reads the damper position based on the combination of the signals output from the terminals of the connectors CN-1 to CN-3.

FIG. 2 is a time chart showing an example of state change during boiler operation. In the time chart of FIG. 2, since the combustion is stopped, the first damper opening is at the ignition position (stop position), and the operation of the blower is stopped. When the output of the combustion command is performed to the boiler, the boiler starts combustion. When combustion is started, a pre-purge step is performed before ignition in order to perform ignition in a state where no fuel component remains in the combustion chamber. In the pre-purge process, the operation of the blower is started, and the damper position is set to the high combustion position to supply air into the combustion chamber to ventilate the combustion chamber.

In the operation control device 7, ventilation of the combustion chamber is continued until the pre-purge time ends, and when the pre-purge time ends, the process proceeds to the ignition step. In the ignition process, since the air is blown off when the air amount is large, ignition is performed with the damper position as the ignition position. In the operation control device 7, when the ignition process is completed, the process proceeds to the low combustion process. The damper position at low combustion has an opening degree larger than the damper position at the time of ignition, and the opening degree of the damper is opened to the low combustion position. Thereafter, when the amount of combustion of the boiler is changed to high combustion, the amount of air supplied for combustion is larger than that during low combustion, so the damper opening degree is opened to the high combustion position. The same applies when reducing the amount of combustion. When changing from high combustion to low combustion, decrease the opening of the damper by one step, and when changing from low combustion to the ignition position, open the damper. Make it one more step smaller.

Next, the operating condition of the damper and the output condition of the damper position information will be described based on FIG. 4 to FIG. 6 and FIG. FIGS. 4 to 6 show the conduction route in the damper control circuit in each state, and FIG. 4 describes the conduction state in the damper control circuit in the state where the damper at the ignition position is moved to the low combustion position. ing. In this case, at the stage before the start of operation, as described in the column before the start of low combustion transition described in FIG. 10, RY1. RY2. RY3 is turned off and cm1. Cm2. Cm3 is turned off. There is. When current flows in this state, no current is supplied to the damper control motor, and the damper position information at this time is that the CN-1 • 3.4 • of the connector is de-energized and CN_2 • 5 is energized. It will be Damper position information in which the CN-1 · 3 of the connector is OFF and the CN-2 is ON is input to the operation control device, and the damper position is determined based on the position information.

When changing the damper opening degree to the low combustion position from this state, the damper control circuit changes RY 3 from OFF to ON as described in the column of ignition → low combustion in FIG. In this case, current flows in the damper control circuit as shown in FIG. In FIG. 4, since the current flows in the opening direction in the damper control motor, the damper blades are moved in the direction to increase the opening degree. In the damper position information in the middle of the opening degree change, the connector CN-1 · 2 · 3 · 5 is ON, and CN-4 is OFF.

Thereafter, the damper is moved in the open direction until cm2, which is a limit switch for low combustion position detection, is turned on. cm2 is turned on / off based on the limit signal of the low combustion position, and the damper is turned off when the damper is closed than the low combustion position, and is turned on when the damper is opened than the low combustion position. Therefore, current flows in the opening direction to the damper control motor until the damper reaches the low combustion position, and the damper is driven in the opening direction.

When the damper blade reaches the low combustion position and the cm 2 limit signal switches from OFF to ON, current flows in the path described in FIG. In this case, since the current to the damper control motor is stopped, the movement of the damper is stopped. Then, the connector CN-1 · 3.5 changes from ON to OFF, and CN-4 changes from OFF to ON. The operation control device takes in the damper position information sent from the damper control circuit and detects the damper position. If the damper position information is ON in CN-2 and OFF in CN-1 · 3, the damper position is the low combustion position, and the operation control device confirms that the damper position is correct.

In the limit switch, as described in FIG. 7 and FIG. 8, the switch is switched depending on the presence or absence of pressing by the cam. When the end of the switch is pressed by the cam provided on the shaft of the damper as described in FIG. 7, the switch portion is pushed down to the lower contact, and current flows in the lower contact. Then, as shown in FIG. 8, when the pressing by the cam disappears, the switch portion is lifted up to the upper contact, and current flows in the upper contact. Because of this configuration, the limit switch causes current to flow to one of the two contact points.

However, due to the abnormality of the limit switch, in rare cases, as shown in FIG. 9, a state in which the two contact points are not in contact may occur. The flow of current in the damper control circuit in this case is as shown in FIG. Since no current flows through either of the two contacts at cm 2, what was originally supposed to be ON at CN-4 of the connector as described in FIG. 5 is beyond the limit switch cm 2 Since no current flows in CN-4, CN-4 is turned OFF, and the damper position information input to the operation control device 7 is erroneous. Even in this case, power is supplied to the damper control motor until the damper position reaches the low combustion position, and the damper position reaches the low combustion position and there is no pressing on the limit switch cm2, so the damper control is performed through cm2 Since the current flowing to the motor is lost and the damper control motor stops driving, the damper is moved to the low combustion position and stopped. In this case, since the supply amount of the combustion air is the target supply amount for low combustion, no abnormality in combustion has occurred. However, if the operation control device 7 determines that the damper position is abnormal based on the incorrect damper position information, the operation of the combustion device is forcibly stopped due to the abnormality of the damper position.

Although the function of forcibly stopping when an abnormality occurs is necessary, the above-mentioned abnormality only can not confirm the position of the damper, and the damper is stopped at the correct position. And the above-mentioned abnormality in the limit switch is often a temporary thing that recovers immediately. Therefore, in the case of this abnormality, it is preferable to continue the operation without making it an abnormality for stopping the operation of the combustion apparatus. However, if the damper position is unknown, no countermeasure is taken simply by ignoring the abnormality, which is not preferable because the abnormality is not dealt with if the damper position is actually abnormal.

Therefore, in the operation control device, when performing control to move the damper, when the damper control motor of the damper control circuit is energized, detection of the energized state at the position where the voltage is always applied is performed, and the energization detection unit It is normal in the part excluding the part where the erroneous signal may be output when the fine operation characteristic is detected in the limit switch after detecting the change from energization ON to OFF and of the damper position information. If it can be confirmed, the damper position is not abnormal.

In this damper control circuit, a voltage is always applied when power is supplied to the damper control motor by CN-1 or CN-3 of the connector, so if CN-1 or CN-3 changes from ON to OFF , Will meet the first condition. Since the damper control motor of the damper control circuit rotates the phase of the current by 90 ° with the capacitor and rotates it, for example, when a current is applied to CN-1 to operate it in the open direction, the current of CN-3 is also out of phase It flows and turns ON. The fact that CN-1 or CN-3 has changed from ON to OFF means that the damper control motor has been switched from being in the energized state to being stopped, and has stopped after moving the damper position. Since it is known that there is a low combustion damper position signal, there is a high possibility that it is not an abnormality for stopping the combustion.

And since the limit switch that micro operation characteristic may occur here is cm2, and it is CN-4 that outputs an incorrect signal when the micro operation characteristic occurs in cm2, except CN-4 If normal damper position information is obtained at the remaining connector terminals, the second condition is satisfied.

In the operation control device, when a low-combustion damper position signal is input from the connector CN-1 · 2 · 3, a signal that is normal except in the part that may be affected by the occurrence of the fine operation characteristic Is confirmed to have been output. In that case, it is possible to estimate that the abnormality is occurring not at the position of the damper but at the limit switch. In this embodiment, since the above two conditions are satisfied, the damper position is not abnormal.

On the premise that a slight operating characteristic occurs, the position check of the damper is performed in a state where it is determined that the limit switch is normal whether it is ON or OFF. Therefore, the abnormality is an abnormality in the limit switch, and it is possible to prevent the operation of the boiler from being stopped until the damper is operating normally. Even when using a limit switch with a fine operation characteristic, a position with high accuracy Confirmation is possible.

When it is determined that only the limit switch is abnormal as described above, the operation of the boiler is not stopped. As a result, although the limit switch generates a fine operating characteristic, it can be said that the boiler continues to operate.

The present invention is not limited to the embodiments described above, and many modifications can be made by those skilled in the art within the technical concept of the present invention.

1 combustion device 2 damper control circuit 3 blower 4 damper device 5 limit switch 6 air passage 7 operation control device 8 cam 9 damper control motor

Claims (1)

A combustion apparatus comprising a burner unit, a blower for supplying air to the burner unit, and an operation control device for changing an air supply amount according to a process of operation ,
Has a damper control motor and the damper blade, the damper device for regulating the amount of air supplied to the burner unit by driving the damper blade in the damper control motor,
A damper control circuit for controlling the energization of the damper control motor based on a command which the operation control device outputs,
A limit switch said detects the position of the damper blade to switch the current path in the damper control circuit,
In the combustion apparatus having a connector for sending the damper position information created from the status of the current path in the damper control circuit to the operation control device,
The damper control circuit, the detected energization state in always a voltage according positioned during energization of the damper control motor, detects that the current state changes to OFF from ON, and out of the damper position information, the If it has been confirmed that the limit switch is normal except where there is a possibility that an erroneous signal may be generated when a phenomenon in which the limit switch stops at an intermediate position between the contacts occurs due to the fine operation characteristic. the not be a state where the damper position information is intended, combustor damper position is characterized by the determination go such made that it is abnormal.

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