JP2952681B2 - Boiler system combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention controls the combustion state at three positions between a high and low combustion state and a combustion stop state according to a steam load, and cooperates with the control. Therefore, the present invention relates to a boiler-based combustion control device that also controls the positioning of a damper for adjusting the amount of combustion air. Further, the present invention relates to an improvement in which a combustion state control operation is relatively delayed to prevent blowout and misfire or oscillating combustion.

<Conventional technology> Three-position combustion control of this type and the positioning control of a damper cooperating therewith are being actively performed for small and medium-sized boiler systems. When the combustion control to the combustion state is performed, the position of the damper is simultaneously and simultaneously lowered from the high combustion position (the position where the air passage cross-sectional area becomes large) corresponding to the high combustion state. Usually, positioning control is performed toward a low combustion position (a position where the cross-sectional area of the air passage is reduced) corresponding to the combustion state.

Apart from this, when shifting from the low combustion state to the high combustion state, a configuration in which the combustion state control operation is relatively delayed with respect to the damper opening operation has often been adopted. That is, from the viewpoint of economy, in recent years, there has been a tendency to shift fuel to heavy oil. In this case, if the fuel is shifted to a high combustion state before the damper opening operation is completed, high combustion in a state in which the damper is half-opened is performed. Insufficient air volume due to the condition often results in incomplete combustion and the generation of black smoke.To resolve this, the end of the damper opening operation is detected, and In some cases, a configuration to start the migration was adopted.

<Problems to be solved by the invention> However, in the above-described conventional apparatus, as long as the transition from the high combustion state to the low combustion state is performed, the positioning control operation of the damper (that is, the damper closing operation in this case) is not performed. Therefore, no configuration is employed in which the combustion control operation (i.e., in this case, the operation for shifting to the low combustion state) is relatively delayed, so that the damper is not used when shifting from the high combustion state to the low combustion state. However, while still not fully closed, while a considerable amount of air is remaining introduced into the combustion chamber, the fuel supply amount suddenly decreases to shift to a low combustion state, and as a result, There is a problem that the burner flame blows out in the machine room and misfires and oscillating combustion occur frequently.

<Means for Solving the Problems> Accordingly, the present invention has been made in view of the problems of the above-described conventional apparatus, such as blowout and misfiring at the time of transition from the high combustion state to the low combustion state. At the time of shifting to, the damper is closed and the damper corresponding to the low combustion state ends the positioning control operation to the low combustion position and the start point of the positioning control operation to the low combustion position after a predetermined period of time has elapsed. The above-mentioned problem is solved by delaying the time point of the control operation for switching the fuel supply amount from the high combustion value to the low combustion value until the earlier time point among the time points, and at the time of shifting to the low combustion state,
The burner flame does not blow out and misfires or oscillating combustion does not occur frequently, and even before the end of the positioning control operation of the damper to the low combustion position, the control operation for switching the combustion supply amount to the low combustion value is executed. By making it possible, if the fuel supply amount still remains at the high combustion value under the condition that the damper is completely closed to the low combustion position, even if black smoke is generated, the fuel supply amount can be reduced. By selecting the time of the switching control operation to the low combustion value before the end of the positioning control operation of the damper to the low combustion position, it is also possible to simultaneously solve the two problems of misconduct such as misfire and black smoke. An object of the present invention is to provide an excellent boiler-based combustion control device that makes it possible.

<Function> As shown in FIG. 1, the combustion state control delay means CC reduces the amount of fuel supplied from the fuel supply means 3 and 4 into the combustion chamber in two stages, as shown in FIG. After switching, when the boiler pressure drops to the lower limit pressure value,
Maintain the fuel supply at a high combustion value corresponding to the high combustion state,
When the pressure of the boiler rises to the upper limit pressure value, switching control is performed so as to maintain the fuel supply amount at a low combustion value corresponding to the low combustion state, and the damper means 7 controls the passage of the combustion air introduced into the combustion chamber. The sectional area is increased or decreased according to the position thereof, and the damper position control means DC switches the position of the damper means 7 to two stages, and the fuel supply amount is maintained at a high combustion value by the combustion state control means CC. When the fuel supply amount is maintained at a low combustion value by the combustion state control means CC, the position of the damper means 7 is controlled to the low combustion state by the combustion state control means CC. In the boiler-based combustion control device acting to control the position to the low combustion position corresponding to the low combustion position, the low combustion position detection means LSL is provided by the damper position control means DC from the high combustion position of the damper means 7 to the low combustion position. The combustion state control delay means R detects the end of the positioning control operation to the combustion control means CC until the end of the positioning control operation to the low combustion position is detected by the low combustion position detection means LSL. The control operation for switching the supply amount from the high combustion value to the low combustion value can be delayed, and the low-combustion position control start detecting means Y, ₃ is provided with the damper means 7 by the damper position control means DC.
The start of the positioning control operation from the high combustion position to the low combustion position is detected, and the start of the positioning control operation to the low combustion position is detected by the combustion state control delay time T, by the low combustion position control start detection means Y, _3. It is possible to delay the switching control operation of the fuel supply amount from the high combustion value to the low combustion value by the combustion control means CC from the detected time to a time after a predetermined period of time has been counted. Of the time of the switching control operation delayed by the combustion state control delay means R and the time of the switching control operation delayed by the combustion state control delay timer T, the time of the preceding switching control operation is actually executed. The switching operation is performed to select the time point.

According to a second aspect of the present invention, the switching control operation protection means * further comprises a switching control operation time point selection means *.
If the switching control operation is not performed properly at the time of the preceding switching control operation selected in the step (1), the switching control operation is protected at the time of the lagging switching control operation.

According to the configuration of the invention described in claim 3, the timing after the predetermined period of time in the combustion state control delay time counting means T ends the positioning control operation of the damper means from the high combustion position to the low combustion position by the damper position control means DC. By being selected at a time later than the time, when the control operation for switching the fuel supply amount is incomplete at the preceding end time of the positioning control operation from the high combustion position to the low combustion position of the damper means 7, At the time when the combustion state control delay timer T lags behind the timer for a predetermined period of time, it acts to protect the execution of the fuel supply amount switching control operation.

According to a fourth aspect of the present invention, the timing after the predetermined period of time in the combustion state control delay timer T is determined by the damper position controller DC to control the positioning of the damper 7 from the high combustion position to the low combustion position. By being selected at a time preceding the end time, if the switching control operation of the fuel supply amount is incomplete at the preceding time after the predetermined period of time in the combustion state control delay timer T, the damper means 7 At the time when the positioning control operation from the high combustion position to the low combustion position is delayed, the protection operation of the fuel supply amount switching control operation is protected.

<Embodiment> The configuration and operation of an embodiment of the present invention will be described below with reference to Figs. 1 to 3. Fig. 2
It is a typical sectional view of a boiler system to which a combustion control device of the present invention can be applied. In the figure, a combustion chamber 1
An air passage 2 communicating with the inside is provided, and a nozzle rod accommodating chamber 2a facing the combustion chamber 2 of the air passage 2 is similarly connected to the nozzle chamber 1a facing the combustion chamber 2.
A pair of two combustion nozzle rods 3 and 4 are vertically suspended in parallel with each other, and one of the nozzle rods 3 is for high combustion (to refuel only in a high combustion state), and the fuel connected thereto is provided. A high combustion solenoid valve QH is provided in the supply pipe 5, and the other nozzle rod 4 is for low combustion (to refuel in both high and low combustion states), and has a low fuel supply pipe 6 connected thereto. A combustion solenoid valve QL is provided. These high and low combustion solenoid valves QH and QL are driven by combustion state control means CC whose details will be described later with reference to FIG. The wind path 2 extends in the lateral direction, and the other end is connected to the blower F. The end of the wind path 2 on the side of the blower F and the nozzle rod storage chamber 2a
And a damper 7 is disposed between them. Damper 7 is wind path 2
And is rotationally driven by a damper motor DM to change the effective cross-sectional area of the wind path 2 according to the rotation angle position. The amount of air pumped toward the combustion chamber 1 can be adjusted. That is, the damper 7 is rotationally driven by a damper motor DC controlled by a damper position control means DC whose details will be described later based on FIG. It moves between a position where the cross-sectional area of the road 2 is enlarged) and a low combustion position corresponding to a low combustion state (a position where the cross-sectional area of the wind path 2 is reduced), and is positioned and controlled at two different positions. It is.

In this case, the damper 7 has a low combustion position detection switch LSL which operates in conjunction with the damper 7 to switch when the damper 7 reaches the low combustion position, and a high combustion position which also switches when the damper 7 reaches the high combustion position. A detection switch LSH is also provided, and the former low combustion position detection switch LSL constitutes a low combustion position detection means for detecting the end of the positioning control operation of the damper 7 from the high combustion position to the low combustion position. ing.

Returning to the combustion chamber 1, it is surrounded by a number of heat-receiving water tubes 8, which are provided with a pressure limit switch GL which operates in response to the vapor pressure there.
And a starting pressure limit switch X. Pressure limit switches GL embodiment, closed at 7 Kg / cm ² or less vapor pressure, is intended to open at 8 Kg / cm ² or more vapor pressure, activation pressure limit switch X is 8 Kg / cm ² or less vapor It is closed by pressure.

FIG. 1 is a circuit block diagram showing the configuration of one embodiment of the combustion control device of the present invention.

In the figure, a power supply line L is connected via a make contact X of a start-up pressure limit switch X to a publicly-known boiler controller BC which is frequently used as this type of three-position combustion control. to do this the auxiliary relay control terminal c1, and make contact g ₁ of the pressure limit switch GL,
An auxiliary relay Y as low combustion position control start detection means for detecting the start of the positioning control operation from the high combustion position to the low combustion position of the damper 7 is connected in series to ground E in that order, and the fuel Between the supply control terminal c2 and the ground E,
A low-burning solenoid valve QL is inserted, and between the control terminal c2 and the ground E, the low-burning position control start detecting means is connected to the low-burning position as described later so as to bypass the solenoid valve QL. A timer T as a combustion state control delay timer for delaying the control operation for switching the fuel supply amount from the high combustion value to the low combustion value from the time when the start of the positioning control operation is detected to the time after the clocking of the predetermined period. The switching control of the fuel supply amount from the high combustion value to the low combustion value until the time when the low combustion position detection means LSL detects the end of the positioning control operation from the high combustion position to the low combustion position, as described below. The break contact of the auxiliary relay R as a combustion state control delay means for enabling the operation to be delayed and the high combustion solenoid valve QH are connected in series in that order, and furthermore, between the blow control terminal d3 and the ground E thereof. , Blower F is connected Then, generally, when the fuel supply amount supplied from the fuel supply means 3 and 4 into the combustion chamber is switched to two stages, and the boiler pressure decreases to the lower limit pressure value, the fuel supply amount corresponds to the high combustion state. Combustion state control means for maintaining a high combustion value and performing switching control to maintain the fuel supply amount at a low combustion value corresponding to the low combustion state when the pressure of the boiler rises to the upper limit pressure value.
CC is configured.

Further, a movable contact cl of a low combustion position detection switch LSL as a low combustion position detection means and a movable contact ch of a high combustion position detection switch LSH are commonly connected to the power supply line L, and each of the detection switches LSL and LSH is connected. Break side fixed contact bl, bh
Are connected to the respective drive terminals of the damper motor DM via the make and break contacts 1 and y2 of the auxiliary relay Y described above. An auxiliary relay R is inserted between the make-side fixed contact al of the low combustion position detection switch LSL and the ground E, and the position of the damper 7 is switched in two stages as a whole. When the supply amount is maintained at the high combustion value, the position of the damper 7 is controlled to the high combustion position corresponding to the high combustion state, and the combustion state control means is controlled.
When the fuel supply amount is maintained at the low combustion value by the CC, a damper position control means DC for controlling the position of the damper 7 at the low combustion position corresponding to the low combustion state is configured.

Further, a break contact 3 of the auxiliary relay Y and a timer T for immediate operation delay recovery are inserted in series between the power supply line L and the ground E in this order.

In operation of the above configuration, as apparent from the waveforms of the main parts in FIG. 3, first, when the vapor pressure in the water pipe 8 decreases according to the load and reaches 8 kg / cm ₂ (FIG. 3 (a) a), the starting pressure limit switch X is actuated, the make contact x thereof is closed (FIG. 3 (b) b), and power supply to the boiler controller BC is started. As a normal operation of the controller BC, the blower F is driven in advance to pre-purge the combustion chamber 1, and then the low combustion solenoid valve QL is excited (FIG. 3 (c) c).

When the vapor pressure further decreases and reaches 7 kg / cm ₂ (FIG. 3 (A) d), the pressure limit switch GL is activated this time, and the make contact gl thereof is closed (FIG. 3). (D) e), the auxiliary relay Y is driven by excitation (FIG. 3 (E) f), the break contact 1 is opened, and the make contact y2 is closed.

In this state, as is apparent from FIG. 1, the break side fixed contact bh of the high combustion position detection switch LSH is connected from the power line L.
Power is supplied to the damper motor DM in the opening direction through (FIG. 3 (F) g) and the closed make contact y2 of the auxiliary relay Y (FIG. 3 (E) h) (FIG. 3 (H)). (I) When the damper 7 is driven to open and is opened to the high combustion position, the movable contact ch of the high combustion position detection switch LSH is switched to the make-side fixed contact ah (FIG. 3 (F) j). ), As a result, the power supply to the damper motor DM is cut off, and thus the positioning of the damper 7 is controlled to the high combustion position. However, in the meantime, immediately after the opening operation of the damper 7 is started, the movable contact cl of the low combustion position detection switch LSL is also switched immediately (FIG. 3 (G) k) and separated from the make-side fixed contact al. The power supply to R is interrupted and its break contact closes (FIG. 3 (I) l). On the other hand, during this time, the break contact 3 of the auxiliary relay Y is turned open by the excitation drive of the auxiliary relay Y (FIG. 3 (E) f), so that the timer T is de-energized (FIG. 3 (J) m). This does not affect the operation of the apparatus, but simply closes the break contact for the timer T to return to the time-delayed operation (FIG. 3 (K) n).

Eventually, at this time, the break contact of the auxiliary relay R and the break contact of the timer T are both closed (FIG. 3 (I) l, FIG. 3 (K) n), and the high combustion solenoid valve QH
Is excited (FIG. 3 (L) o), and a fuel of a high combustion value is supplied into the combustion chamber 1 from both the nozzle rod for low combustion and the nozzle rod for high combustion. Shifts to a high combustion state.

The high combustion state of the device continues, and the vapor pressure eventually reaches 8K
g / cm ² (p in FIG. 3 (A)), the pressure limit switch GL reversely operates, and its make contact gl
Starts to open (FIG. 3 (D) q).

Then, the auxiliary relay Y is de-energized (FIG. 3 (E) r), the start of the positioning control operation to the low combustion position is detected, and the break contact 1 is turned to the closed state.
The make contact y2 turns to the open state, but as shown in FIG. 1 again, the break side fixed contact bl (FIG. 3 (FIG. G) s) and the closed break contact 1 (FIG. 3 (E) t), power is supplied to the damper motor DM in the closing direction (FIG. 3 (H) u), so that the damper is closed. When driven and closed to the low combustion position, the movable contact cl of the low combustion position detection switch LSL is switched to the make-side fixed contact al (v in FIG. 3 (G)), and as a result, to the damper motor DM. Is cut off, and the damper 7 is controlled to be positioned at the low combustion position in the same manner as the above-described positioning control at the high combustion position, but is performed at the time of the next positioning control at the combustion position. It should be noted that the movable contact cl of the low combustion position detection switch LSL is fixed on the make side. When the end of the positioning control operation is connected to the contact al to the low combustion position is detected, and at the same time, is that the auxiliary relay R is driven excitation. As a result, the break contact of the auxiliary relay R starts to open (FIG. 3 (I) w), and at that time, the high combustion solenoid valve QH is in a non-excited state for the first time (FIG. 3 (L)).
x), a low combustion value supply amount of fuel is supplied into the combustion chamber 1 from the low combustion nozzle rod, and the apparatus shifts to a low combustion state.

In other words, regarding the transition of the device to the low combustion state, the transition of the auxiliary relay Y to the non-excitation state (see FIG. 3E)
r) In other words, a delay is applied for a period required from the start time of the positioning control operation to the low combustion position to the actual arrival time of the damper 7 at the low combustion position.
Is executed only after the end of the positioning control to the low combustion position is detected.

At this time, it should be further noted that when the auxiliary relay Y shifts to the non-excited state (FIG. 3 (E) r), the break contact 3 starts to close, so that the timer T is driven again. (FIG. 3 (J) y), the timekeeping operation is started, and this is set as a time point after the end time (FIG. 3 (G) v) of the positioning control operation of the damper 7 to the low combustion position. The elapsed time up to the time point is counted, in other words, the break contact of the timer is opened with the delay return operation up to that time point (FIG. 3 (K) z).

Thus, after all, the time limit operation of the timer T returns to the non-excited state of the auxiliary relay Y (FIG. 3 (E) r), that is, from the start of the low combustion positioning control operation of the damper 7. Until the time after the predetermined time is counted, the switching control operation of the device from the high combustion state to the low combustion state can be delayed. Regarding the delay time measured by the timer T in this case, if there is no significant difference in the fuel supply amount between the high and low combustion states, the delay time is increased for the purpose of preventing a misfire when shifting to the low combustion state. After setting (FIG. 3 (K) z), the break contact t of the timer T is opened at a time later than the end of the positioning control operation of the damper 7 to the low combustion position, so that the high level before the time is reached. The transition of the combustion solenoid valve QH to the non-excited state is left to the control of the break contact r, whereby the make-side fixed contact al and the movable contact cl of the low combustion position detection switch LSL as the low combustion position detection means are connected. The time when the interval is closed, that is, the preceding end time of the positioning control operation from the high combustion position to the low combustion position of the damper 7 is selected, and at this time, the auxiliary relay R shifts to the excitation state. Fuel supply Switching control operation to the low combustion value is performed from a high combustion value of the amount. At that time, the damper 7 cannot be controlled to be positioned at the low combustion position due to some obstacle, and the control for switching the fuel supply amount to the low combustion value at the end of the preceding operation of the positioning control operation of the damper 7 to the low combustion position. If the operation is incomplete, the break contact of the timer T is opened at a point in time after the delay time is counted by the timer T as the combustion state control delay timer, so that the fuel supply amount is reduced. A protection system is formed which ensures execution of the switching control operation to the value.

In contrast to this, in the case where the fuel supply amount in the low combustion state is very small and there is a risk of smoke when shifting to the low combustion state, the delay time measured by the timer T is shifted to the low combustion position of the damper 7. By setting the time to be shorter than the time required until the end of the positioning control operation (z 'in FIG. 3 (K)), it is preferable to shift to the low combustion state exclusively depending on the delay time of the timer T. That is, in this case, the break contact of the timer T is opened at a point prior to the end point of the positioning control operation of the damper 7 to the low combustion position, so that
The transition of the high combustion solenoid valve QH to the non-excited state before the end of the positioning control operation of the damper 7 is left to the control of the break contact of the timer T, whereby the timer T as the combustion state control delay timer means The preceding point in time after the measurement of the predetermined delay time is selected, and at this point, the break contact of the timer T is opened to execute the switching control operation of the fuel supply amount to the low combustion value. .
At this time, the timer T cannot complete the timing due to some trouble, and the control operation for switching the fuel supply amount to the low combustion value at the preceding time after the timer T has counted the predetermined delay time has failed. In this case, the auxiliary relay R is set at the end of the delay of the positioning control operation of the damper 7 to the low combustion position.
Is shifted to the excited state, and the break contact of the auxiliary relay R is opened, thereby forming a protection system for ensuring execution of the control operation for switching the fuel supply amount to the low combustion value.

<Effect> As described above, according to the first aspect of the present invention, when shifting from the high combustion state to the low combustion state, the damper is closed,
Delay of the switching control operation which is delayed until the end of the positioning control operation of the damper to the low combustion position, and delay from the start of the positioning control operation of the damper to the low combustion position to the time after a predetermined delay time is counted. By selecting the preceding switching control operation time point from among the switching control operation times to be performed, and performing the switching control operation to the low combustion value of the fuel supply amount at this time point, Even before the end of the positioning control operation of the damper to the low combustion position, the operation of switching the fuel supply amount to the low combustion value can be performed, so in a state where the damper is completely closed to the low combustion position,
Still, if the fuel supply amount remains at the high combustion value, even if the amount of air is too low and black smoke is generated, the fuel supply amount will be at a time preceding the end point of the positioning control operation of the damper to the low combustion position. By selecting the time point of the control operation for switching the supply amount to the low combustion value, an excellent effect is achieved in that misfire due to excessive air amount can be prevented without generating black smoke due to insufficient air amount. You.

According to the second to fourth aspects of the present invention, of the two preceding and succeeding time-series operations for performing the switching control operation of the fuel supply amount to the low combustion value, the preceding operation is performed at the time of the preceding operation. In the case where the switching control operation is not performed properly, the switching control operation is protected at the time of the operation that is delayed, so that the effect of the invention according to claim 1 is not reduced at all, and furthermore, the configuration is improved. Since the reliability and safety of operation can be improved without adding elements,
An excellent effect that cost performance can be remarkably improved is also achieved.

[Brief description of the drawings]

1 to 3 relate to an embodiment of the present invention. FIG. 1 is a circuit diagram showing the configuration, FIG. 2 is a sectional view of the entire boiler, and FIG. It is a waveform diagram. 3, 4 nozzle rod (fuel supply means) 7 damper CC combustion state control means DC damper position control means LSL low combustion position detection means T combustion state control delay means

Claims (4)

(57) [Claims] 1. A fuel supply means (3, 4) which faces a combustion chamber of a boiler and supplies fuel into the combustion chamber, and a fuel supply amount supplied from the fuel supply means (3, 4) into the combustion chamber is switched in two stages. When the boiler pressure decreases to the lower limit pressure value, the supply amount is maintained at a high combustion value corresponding to the high combustion state, and when the pressure increases to the upper limit pressure value, the supply amount corresponds to the low combustion state. Combustion state control means CC for switching control so as to maintain a low combustion value; damper means 7 for increasing or decreasing the passage sectional area of the combustion air introduced into the combustion chamber in accordance with the position thereof; When the fuel supply amount is maintained at a high combustion value by the combustion state control means CC, the position of the damper means is controlled to a high combustion position corresponding to the high combustion state, and the combustion state is controlled. The control means CC When the supply amount is maintained at a low combustion value, the boiler-based combustion control device includes a damper position control means DC for controlling the position of the damper means at a low combustion position corresponding to a low combustion state. A low combustion position detecting means for detecting that the positioning control operation of the damper means from the high combustion position to the low combustion position by the means DC has been completed; A combustion state control delay means R capable of delaying a control operation of switching the fuel supply amount from a high combustion value to a low combustion value by the combustion control means CC until the end is detected; and a damping means 7 by the damper position control means DC. The low combustion position control start detecting means Y, ₃ for detecting that the positioning control operation from the high combustion position to the low combustion position has started, and the low combustion position control start detecting means Y, ₃ Combustion state control that can delay the control operation of switching the fuel supply amount from the high combustion value to the low combustion value by the combustion control means from the time when the start of the positioning control operation to the low combustion position is detected to the time after a predetermined period of time is counted. The preceding switching control of the switching control operation delayed by the delay time counting means T and the combustion state control delaying means R and the switching control operation delayed by the combustion state control delaying time counting means T Switching control operation time point selecting means for selecting the time point of the operation as the time point of the currently executed switching control operation *
And a boiler-system combustion control device. 2. If the switching control operation is incomplete at the time of the preceding switching control operation selected by the switching control operation time selecting means *, the switching control operation is performed at the time of the lagging switching control operation. 2. The boiler-system combustion control device according to claim 1, further comprising a switching control operation protection means * for protecting the execution of the control. 3. The time after the predetermined period of time is counted by the combustion state control delay time counting means T is later than the time when the positioning control operation of the damper means 7 from the high combustion position to the low combustion position by the damper position control means DC is completed. Claim 1.
Or the boiler system combustion control device according to 2. 4. The time point after the predetermined period of time in the combustion state control delay timer means T precedes the end point of the positioning control operation of the damper means 7 from the high combustion position to the low combustion position by the damper position control means DC. Claim 1.
Or the boiler system combustion control device according to 2.