JP2930738B2 - Ignition preparation control method and device for restarting combustion in absorption chillers, water heaters, boilers, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling ignition preparation when restarting combustion in an absorption refrigerator, a chiller / heater or a boiler, and more particularly to a combustion chamber in an absorption refrigerator, a chiller / heater or a boiler. When the combustion is restarted, a combustion preparation control method and apparatus for pre-purge air to remove the residual flame and combustibles, if any, in the combustion chamber or burner, etc. It is about.

[0002]

2. Description of the Related Art An absorption refrigerator or an absorption chiller / heater can take out cold water by changing the concentration of an absorption liquid circulating in a body. For example, in a double-effect absorption chiller / heater, the evaporator, absorber, low-temperature regenerator,
There is a condenser, outside which a high temperature regenerator is provided. An evaporator tube is disposed inside the evaporator, and the refrigerant liquid pumped from the refrigerant pool flows down to the outer surface of the evaporator tube under high vacuum, causing the refrigerant liquid to deprive the latent heat of vaporization, thereby evaporating the evaporator tube. The cold water flowing through is cooled. The cold water is sent to a predetermined heat exchanger installed in a room that needs cooling, and the cold water that has received heat and rises in temperature is returned to the evaporator tube. In the absorber, the refrigerant vapor generated in the evaporator is cooled to absorb the sprayed absorbing liquid, and at the same time, the inside of the body is kept at a high vacuum. The condenser cools and condenses the refrigerant vapor evaporated in the low temperature regenerator and the high temperature regenerator. The low-temperature regenerator heats and concentrates the absorbent using the latent heat of the refrigerant vapor separated and evaporated by the gas-liquid separator of the high-temperature regenerator, and separates and evaporates the refrigerant. In the high-temperature regenerator, the absorption liquid is heated in a vacuum by a combustion device, and a part of the refrigerant is evaporated and separated. In the absorption chiller / cooled / hot water machine performing such operations, the opening of the heating amount adjustment valve of the high temperature regenerator is adjusted by a signal from a temperature sensor provided at the chilled water outlet. If the chilled water outlet temperature is not low enough to obtain the temperature set for cooling, the opening of the heating amount adjustment valve is increased to promote heating, and the absorption chiller / Operated with or near load. The absorption chiller mainly has only the cooling function, but in the case of the absorption chiller / heater,
Not only the cooling operation but also the heating operation can be performed. In the case of both machines, in the case of a double effect type absorber, the absorption liquid is heated by burning gas or oil or introducing high-temperature steam in a high-temperature regenerator. When the gas is burned by the combustion device of the high-temperature regenerator, LPG gas, city gas, natural gas, and the like are used. In such a combustion apparatus that burns fuel gas, the combustion may be stopped or restarted, and the operation of the absorption refrigerator / chiller / heater may be repeatedly started and stopped. This is often performed, for example, as described above, in order to set the chilled water outlet temperature to a predetermined value, or, in some cases, when controlling a plurality of absorption chillers / cooled / hot water machines according to the load. . The operation of the absorption chiller and chiller / heater stopped by the unit control is not stopped at all, but the chilled water that circulates chilled water through the evaporator tube is used in order to exert a slight cooling function with the remaining capacity. The pump and the like are operated. The above-described combustion device includes a combustion chamber for burning fuel gas, a smoke chamber connected to the combustion chamber, and a heat recovery device. Before restarting combustion in such a combustion apparatus, air is used to purge the combustion chamber and the flue. After the previous combustion was stopped, the fuel gas may remain in the combustion chamber and the exhaust path after that. Therefore, the combustibles are expelled by this purge, and thereafter, the air is completely replaced with air. If the combustible is left as it is or if the combustion is restarted with a residual flame, the combustible will ignite rapidly following the restarted combustion, causing an explosion in the combustion chamber or flue. This is to prevent that. Therefore, conventionally, when restarting the combustion, the air is purged into the combustion chamber or the flue for a certain period of time, and after confirming that there is no residual flame in the combustion chamber or the flue, the next combustion is started. I have to. However, if a residual flame is confirmed even after the purge is completed, it is determined that there is an abnormality in the combustion system or the like, and the combustion is not restarted. Such a situation occurs when the fuel shut-off valve, which should have been fully closed at the end of the previous combustion, is in a poorly closed state, and fuel gas is leaking into a combustion chamber, a flue, or the like. In addition, a flame detector is installed to detect whether there is a flame in the burner of the combustion chamber.However, even after the combustion stop command is issued, if the flame detector malfunctions and outputs a signal indicating that there is a flame, In some cases, the fuel cutoff valve is kept open, and the fuel gas flows out more and more. In addition, since the safety device operates when a flame is detected before the combustion operation is started, the absorption chiller / heater is stopped at that time. Therefore, every time the operator has to inspect the combustion system and the like one by one, an extremely troublesome operation requiring a lot of trouble is required. By the way, when LPG gas having a large calorific value is used as fuel gas, after-flame may be detected for a considerably long time even after the combustion is stopped.
If this “afterburning” continues for a long time, a longer purging time is required. However, depending on the operating state, the time from the previous stop to the reception of the next combustion restart command may be short. When the combustion is restarted immediately after receiving the command, if the purge is insufficient and there is residual flame, an explosion or the like will be induced. Therefore, even if there is a command to restart combustion, if the elapsed time after stopping the previous combustion is short, the combustion is continued until a preset time, for example, several minutes, at which it is estimated that the afterburning will be stopped, for example, several minutes has elapsed. The control which is regulated so as not to restart is adopted.

[0003]

There are city gas, natural gas and the like used as fuel gas. However, when these fuel gases are used, even if there is post-burning, LPG is used.
It generally disappears in a much shorter time than the case of gas, for example, about 30 seconds. The control sequence for limiting the combustion restart time as described above is incorporated in the control device provided in the absorption chiller / chiller / heater, but according to the fuel gas used for each absorption chiller / chiller / heater. Equipped with a control device that controls by changing the time limit,
The management becomes more troublesome in the manufacturing process. Therefore, in general, the LPG that requires the longest time limit
A sequence for preparing for combustion according to the gas is uniformly employed. This is an absorption refrigerator using LPG gas.
Even if an appropriate time is set for a chiller / heater, an absorption chiller or chiller / heater using city gas or natural gas, etc. Until the elapse of the elapsed time, the restart of combustion is prevented, and there is a problem that rapid restart of the operation of the absorption refrigerator / cooled / hot water machine is hindered. Needless to say, since the purging is continued during that time, useless purging is performed. The present invention has been made in view of the above problems,
The purpose is that the same control sequence can be used to prepare for the restart of combustion in the combustion devices used in absorption chillers, water heaters, hot water heaters, boilers, etc., regardless of the type of fuel gas. Appropriate purge time for each fuel gas to be used, to enable quick restart of operation according to the type of fuel gas, and to reduce power consumed for unnecessary prepurge. It is an object of the present invention to provide an ignition preparation control method and apparatus for restarting combustion in an absorption refrigerator, a chiller / heater, a boiler, and the like.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an absorption refrigerator,
A combustion chamber that supplies and burns fuel gas and a flue connected to the combustion chamber are installed in water heaters and boilers,
The present invention is applied to a combustion apparatus in which air is used to pre-purge the combustion chamber and the flue before starting combustion in the combustion chamber. The features of the method invention are as follows:
Referring to FIG. 1, initial purging of air into combustion chamber 9A, flue 9B, and the like is continued until afterflame after stopping combustion of fuel gas is no longer detected from burner 17, combustion chamber 9A, or the like. Then, after the after-flame is no longer detected, the igniting and burning in the combustion device 9 are performed after pre-purging with the minimum necessary air amount. In the invention of the apparatus, the burner 17 and the combustion chamber 9A
For example, a flame detector 19 for detecting the presence or absence of residual flame is provided. Further, an air control valve 13 that is opened to supply the air sent from the blower 12 to the combustion chamber 9A, the flue 9B, and the like is provided. After the combustion of the fuel gas is stopped, a signal for opening the air control valve 13 is output until the after-flame detection signal from the flame detector 19 disappears. After the time T has elapsed, a signal for closing the air control valve 13 is output, and when the after-flame detection signal from the flame detector 19 is also output after the quenching set time t has elapsed, the air control valve 13 An ignition preparation control means 16 for outputting a signal for maintaining the opening and outputting a pre-warning signal is provided.

[0005]

When the combustion is restarted, the air control valve 13 is opened by a command from the ignition preparation control means 16, and the initial purge is started to the combustion chamber 9A, the flue 9B and the like. When the flame detector 19 outputs a signal indicating that there is a residual flame in the burner 17, the combustion chamber 9A, or the like, the initial purge is continued. If the afterflame is not detected before the quenching set time t elapses, the air from the air control valve 13 is pre-purged until the minimum amount has passed the pre-purge set time T. When the pre-purge set time T elapses, the air control valve 13 is closed upon receiving a signal from the ignition preparation control means 16, even if the supply of purge air is completely stopped and the fuel gas is burned thereafter. No explosion occurs in the combustion chamber 9A or the flue 9B. Thereafter, an ignition operation for restarting combustion can be started. by the way,
If the detection of the afterflame continues even after the elapse of the quenching set time t,
The initial purge is continued as it is. At the same time, a pre-warning signal is output from the ignition preparation control means 16, and a warning that there is a residual flame is issued from the pre-warning device, and the combustion device 9 is activated.
And so on.

[0006]

According to the present invention, the processing can be performed in exactly the same sequence regardless of whether LPG gas is used in the combustion apparatus, or where city gas or natural gas is used. When city gas or the like is used, the prepurge is completed in a short time. Thus, regardless of the type of fuel gas used, preparation for combustion at the time of ignition can be quickly performed regardless of the specifications of the machine body or the type of fuel gas. Therefore, when city gas or the like is used, unnecessary continuous prepurge for a long time is avoided, and power consumption for that purpose is also reduced. Further, as long as the detection of the afterflame continues, it is possible to notify the abnormality of the combustion system.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments. 1 and 2 are configuration diagrams of an example of a double-effect absorption chiller / heater, and FIG. 2 is a left side portion of the configuration.
Is a right side portion, and in both figures, a functional device of one machine and its control system are shown. In such a machine, not only the absorption chiller / heater having the cooling and heating functions but also the absorption chiller having the cooling function, etc., due to a change in the concentration of the circulating absorption liquid, the evaporator tube arranged in the evaporator 1. 1A, the cold water 21 can be taken out. For this reason, the inside of the body that has been vacuumed,
An evaporator 1, an absorber 2, a low-temperature regenerator 3 and a condenser 4 are provided, and outside the body, a high-temperature regenerator 5 connected to the absorber 2 and the low-temperature regenerator 3 and a heat exchanger for absorbing liquid are provided. A low-temperature heat exchanger 6 and a high-temperature heat exchanger 7 for performing the operation are provided. In the following description, the cooling operation in the absorption chiller / heater will be described, and the description of the cooling operation in the absorption chiller that functions similarly will be omitted. A pipe for taking out cold water 21 is connected to an evaporator tube 1 </ b> A disposed inside the evaporator 1, and a temperature sensor 8 for detecting a cold water outlet temperature is provided on the pipe. The high-temperature regenerator 5 is provided with a combustion device 9 for burning LPG gas, city gas, or natural gas. A quantity regulating valve 10 is provided. Accordingly, when the outlet temperature of the chilled water 21 due to the absorption refrigeration action is different from the control set value, the supply heat source amount is received in response to a command from the combustion control device 15 so that the control set value is obtained as the outlet temperature. It is adjusted by changing the valve opening of the heating amount adjusting valve 10. The heating amount adjusting valve 1
A fuel cutoff valve 11 for supplying combustion gas is provided on the upstream side of 0. In such an absorption chiller / heater, when the cooling operation is temporarily stopped, the fuel cutoff valve 11 is closed. However, even after the closure, the burner 1
It is inevitable that part of the fuel gas remains in the combustion chamber 7 and the combustion chamber 9A. Therefore, "afterburning" of the remaining fuel occurs in the burner 17, the combustion chamber 9A, and the like. In such a state, there is a case where it is desired to restart the combustion in the combustion device 9. At this time, if combustion is restarted immediately, there is a danger of explosion and the like, so that air is pre-purged into the combustion chamber 9A, the flue 9B and the like. Blower 12 and air control valve 13 for that purpose
Is provided. Note that the blower 12 is operated not only for pre-purge and the like but also for supplying combustion air even after starting combustion. For the burner 17 and the combustion chamber 9A,
A known flame detector 19 is installed to burn the remaining fuel gas and detect the residual flame before the residual combustible is expelled by the air for the initial purge. on the other hand,
The combustion control device 15 provided in the absorption chiller / heater is provided with ignition preparation control means 16 incorporating a sequence up to combustion at the time of ignition. This is regardless of the type of fuel gas used in the combustion device 9 of the absorption chiller / heater,
A command for controlling the prepurge can be output. After stopping the combustion of the fuel gas, the ignition preparation control means 16 outputs a signal for opening the air control valve 13 until there is no residual flame detection signal from the flame detector 19. On the other hand, a signal for closing the air control valve 13 is output after the pre-purge set time T has elapsed from the time when the after-flame detection signal disappears. When the after-flame detection signal from the flame detector 19 is output even after the quenching set time t has elapsed, a signal for maintaining the opening of the air control valve 13 is output and a pre-warning signal is output. It is like that. During the pre-purge setting time T, the combustion chamber 9A and the flue 9B are purged with the minimum amount of air necessary for restarting the next combustion. For example, it is about four times.

With the above configuration, control for preparing for combustion at the time of ignition is performed as described below. This will be described below with reference to the flowcharts shown in FIGS. When a combustion restart command is received (Step 1, hereinafter referred to as S1, etc.), the ignition preparation control means 16
Command to open the air control valve 13 (S2). This starts purging of air into the combustion chamber 9A, the flue 9B, and the like. After the air control valve 13 is fully opened (S
3) When the flame detector 19 outputs a signal indicating that there is a residual flame in the combustion chamber 9A, the burner 17, or the like (S)
4) Before three minutes of the flame-extinguishing set time t have elapsed (S5), the air control valve 13 is maintained in the fully opened state, and the air sent from the blower 12 is initially purged (S5).
6). The timer operates from the time when the air control valve 13 is fully opened, and if the after-flame is no longer detected (S4) before the elapse of 3 minutes of the flame-extinguishing set time t (S5), the air control valve 1
With the air from 3, the minimum amount in the absorption chiller / heater is pre-purged (S7). The timer is activated from the point when the afterflame is no longer detected and continues until the pre-purge set time T, for example, 35 seconds, elapses. This 35 seconds is selected as a time sufficient to supply an air volume of, for example, four times or more the volume of the combustion chamber 9A, the flue 9B, the high-temperature heat exchanger 7, the smoke chamber, and the like. After 35 seconds have elapsed (S8), the air control valve 13 is closed upon receiving a signal from the ignition preparation control means 16 (S9). At this time, the supply of the purge air is completely stopped, and even if the fuel gas is burned thereafter, no explosion occurs in the combustion chamber 9A, the flue 9B, and the like. Then, after it is detected that the air control valve 13 is fully closed (S10), the combustion control device 15
The pilot gas solenoid valve 18 for supplying the pilot gas for ignition to the burner 17 of the combustion chamber 9A is opened according to the command from (S11). At the same time, the transformer for ignition is turned on (S12). Of course, combustion air is also supplied from the blower 12. When the flame detector 19 detects that the pilot gas has been ignited (S13), the fuel cutoff valve 11 that supplies the fuel gas to the burner 17 is opened (S14). If the flame detector 19 does not detect the flame of the pilot gas, it is determined that the ignition of the pilot gas has failed, and an abnormal signal is output (S15). When the timer is operated from the time point of step 14 and the set predetermined five seconds have elapsed (S16), the pilot gas solenoid valve 18 is closed (S17). If the fuel gas is ignited, the flame is detected by the flame detector 19 (S18), and the absorption chiller / heater starts the automatic combustion operation (S1).
9). If no flame of the fuel gas is detected by the flame detector 19, it is determined that the main ignition has failed, and an abnormal signal is output (S20). In that case, the worker will investigate the combustion system and the like. To re-ignite, the procedure from step 9 and the like may be followed again.
By the way, in step 4, after-flame detection is continued, and after the extinction set time t, for example, 3 minutes, which is set by a timer that has been activated since the air control valve 13 is fully opened (S5), after-flame is detected. Then (S4), the initial purge is continued with the air control valve 13 fully opened (S21), and the absorption chiller / heater is left as it is. At the same time, a pre-warning signal is output from the ignition preparation control means 16, and a warning that there is a residual flame is issued from the pre-warning device 20 (S22). Upon receiving the sound of the alarm lamp 20a or the sound of the alarm buzzer 20b, the worker inspects the combustion device 9 and the like. After three minutes (S5), there is an afterflame, which is impossible in the normal state. However, such a residual flame means that the fuel shut-off valve 11 should be fully closed when the previous combustion was terminated, but a malfunction occurred in the closing operation, and the fuel was discharged. It is the case that it is leaking.

The above-described operations from step 1 to step 22 are performed in exactly the same control sequence regardless of whether LPG gas is used for the absorption chiller / heater, or whether city gas or natural gas is used. I have. Therefore,
When LPG gas is used, the residual flame time in the previous combustion is longer than when city gas is used, but no residual flame is detected regardless of the length of the time. At that point, prepurge can be entered. As a result, in the case where city gas or the like is used, the time until no after-flame is detected is short, but at that point, the process immediately proceeds to the next step. Therefore, according to the sequence in the ignition preparation control means, in the absorption chiller / heater using any type of fuel gas,
The same control sequence according to each fuel gas can be applied, and preparation for combustion at the time of ignition can be performed regardless of the specifications of the absorption chiller / heater and the type of fuel gas. In addition,
Even if LPG gas is used, its components may be slightly different from each other, and even in such a case. Therefore, the purging time is minimized, so that unnecessary purging is avoided when city gas or the like is used, and power consumption for that purpose is also reduced. Even if the fuel gas is city gas, if the fuel shut-off valve is kept open as described above, it is possible to know the abnormality of the combustion system as long as the detection of the afterflame continues. it can.
The above description has been made with reference to an absorption chiller / heater, but the invention can also be applied to an absorption refrigerator or a combustion device such as a boiler. And, by installing them multiple units,
It can be said that this method is particularly preferable when the number of operating units is changed each time according to the load, and the combustion operation in the combustion device of each unit is frequently started and stopped.

[Brief description of the drawings]

FIG. 1 is a configuration diagram corresponding to the right half of an apparatus including a system in which the control of the present invention is applied to an absorption chiller / heater.

FIG. 2 is an apparatus configuration diagram in the left half of an absorption chiller / heater to which the present invention is applied.

FIG. 3 is a flowchart for explaining the first half of the combustion restart control.

FIG. 4 is a flowchart illustrating the latter half of the combustion restart control.

[Explanation of symbols]

9: Combustion device, 9A: Combustion chamber, 9B: Flue, 12: Blower, 13: Air control valve, 19: Flame detector, 16: Ignition preparation control means, 20: Pre-alarm, T: Pre-purge setting time, t: extinction setting time.

Claims (2)

(57) [Claims] An absorption refrigerator, a chiller / heater, a boiler, and the like are provided with a combustion chamber for supplying and burning fuel gas and a flue connected to the combustion chamber, and before starting combustion in the combustion chamber, In a combustion apparatus in which air is used to pre-purge the combustion chamber and the flue, the combustion chamber and the smoke until the after-flame after stopping the combustion of the fuel gas are not detected from the burner or the combustion chamber. Continue the initial purge of air to the road, etc., and when no afterflame is detected,
A method for controlling ignition preparation at the time of restarting combustion in an absorption refrigerator, a chiller / heater, a boiler, or the like, wherein ignition and combustion are performed in a combustion device after pre-purge with a minimum necessary amount of air. 2. A combustion chamber for supplying and burning a fuel gas, a flue connected to the combustion chamber, and the like are provided in an absorption refrigerator, a chiller / heater, a boiler, etc., and before starting combustion in the combustion chamber, In a combustion apparatus that pre-purges the combustion chamber or flue using air, a flame detector is provided in the combustion chamber or burner, and detects the presence or absence of residual flame in the combustion apparatus. An air control valve that is opened to supply incoming air to a combustion chamber, a flue, or the like, and the air control valve until the after-flame detection signal from the flame detector disappears after the combustion of the fuel gas is stopped. While outputting the signal for opening the valve, after the lapse of the pre-purge set time from the time when the residual flame detection signal disappears, while outputting a signal for closing the air control valve, the residual flame detection signal from the flame detector is Extinction An ignition refrigeration control unit that outputs a signal for maintaining the opening of the air control valve when it is output even after a lapse of a set time, and that outputs a warning signal. Preparation control device for restarting combustion in water heaters, water heaters and boilers, etc.