JPH0652128B2 - Boiler combustion control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a combustion control method for a boiler, which controls a combustion amount in multiple stages according to a load state.

[Conventional technology and its problems]

Generally, in the combustion control method for thermal equipment such as a boiler, if a misfire occurs during combustion, the fuel supply is stopped and an interlock is applied, so that the boiler cannot be restarted unless the interlock is released. (Fail Safety).

There are various possible causes of misfire, such as abnormal fuel system and abnormal blower system. In a three-position combustion control system (controlling combustion amount in three stages: stop, low combustion, high combustion) May be good at low combustion, but may misfire during transition from low combustion to high combustion or during high combustion.

The main cause of misfire in this case is the imbalance of the air-fuel ratio due to clogging of the fuel solenoid valve and burner nozzle.However, according to the conventional combustion control method, the misfire interlock causes the boiler to stop. The steam supply is also stopped.

[Means for Solving the Problems]

This invention continues combustion on the safe side as much as possible and supplies a little steam if combustion in a low combustion state is possible even if misfire occurs during transition from low combustion to high combustion or during high combustion. Specifically, it is a combustion control method that uses a combustion control circuit for controlling the combustion amount of the boiler in multiple stages, and is used for both low combustion to high combustion transition and high combustion. In case of misfire, the feature is that the boiler is restarted to forcibly continue combustion in a low combustion state.

[Action]

According to the present invention, even if a misfire occurs during transition from low combustion to high combustion and during high combustion, if continuous combustion in a low combustion state is possible, restart the boiler to burn in a low combustion state. Can be continued and steam can be continuously supplied.

〔Example〕

A preferred embodiment of the present invention will be described below with reference to the drawings, but a three-position combustion control type boiler will be described as an example.

In the figure, (1) is a boiler equipped with a burner (3) for heating. The combustion air connects the burner (3) and the blower (4) by a blower duct (5) and is sent through this blower duct. A damper (6) for adjusting the air volume is provided in the air duct (5), and its operation can be operated by the damper drive means (7). The damper is selectively moved between two positions, a high combustion position and a low combustion position, in order to control the low combustion air volume and the low combustion air volume.

A fuel supply line (8) is connected to the burner (3), the downstream side of a fuel pump (9) inserted in this line is branched into a high combustion line and a low combustion line, and the respective branch lines A solenoid valve for high combustion (10) and a solenoid valve for low combustion (11) are inserted separately in the. Open both high combustion solenoid valve (10) and low combustion solenoid valve (11) during high combustion, and low combustion solenoid valve during low combustion
Only (11) is opened, and switching between high combustion and low combustion follows the opening / closing operation of the high combustion solenoid valve (10). (12) is a fire detection sensor that detects the presence or absence of a fire, that is, the occurrence of a misfire.

The pressure detector that detects the internal pressure of the boiler can determine which operating state, high combustion, low combustion, or stop, is selected.
It is controlled by the combustion control circuit (2) based on the signal of (13). The pressure detector may be, for example, a pressure switch PS having two set pressure values, a high set pressure value and a low set pressure value.
Control to control high combustion at pressures below the low set pressure value, low combustion at pressures between the low and high set pressure values, and stop at pressures below the high set pressure value. To do.

(14) is a water level detector for detecting the water level in the boiler can. Based on the signal from this detector, an appropriate water level control device turns on the water supply pump (16) in the water supply line (15).
-Turn off to keep the water level in the can at a certain level.

In the device configured as described above, when a misfire occurs during combustion (see FIG. 2), it is determined whether the misfire occurs during transition from low combustion L to high combustion H or during high combustion H (17). )
If so, the boiler is automatically restarted to continue combustion in a low combustion state. Even if the signal from the pressure detector (13) is a high combustion instruction signal, the high combustion will cause a misfire again, so the low combustion is continued and the supply of steam is not stopped. If there is a misfire during ignition or during low combustion, the misfire interlock is applied and the boiler is stopped as in the conventional combustion control.

When a misfire occurs during the transition from low combustion to high combustion or during high combustion, the boiler is restarted and operation continues, but when a misfire occurs, the data is stored and a misfire warning is issued. To do so. Then, at a time when the boiler may be stopped, the boiler is stopped, and the faulty part is inspected and repaired.

The embodiment in which the present invention is applied to the boiler of the three-position combustion control system has been described above, but the present invention can also be used for controlling the combustion amount in multiple stages of four positions or five positions or more.

〔The invention's effect〕

This invention is configured as described above, and even if a misfire occurs during transition from low combustion to high combustion or during high combustion, if combustion in a low combustion state is possible, the boiler is automatically restarted. It is possible to forcibly continue combustion in a low combustion state and continue to supply steam. In this case, the amount of supplied steam is smaller than that during high combustion, but since the supply is not interrupted, it is possible to continue operation without stopping steam-using equipment.

In addition, in a multi-can installation system in which a plurality of boilers are installed and operation is controlled, another boiler can be activated while continuing low combustion to prevent a sudden decrease in the steam amount of the entire system.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a flow chart showing an example of combustion control in the present invention. (1) ... Boiler, (2) ... Combustion control circuit (3) ... Burner, (8) ... Fuel supply line (12) ... Fire detection sensor, (15) ... Water supply line (17) ... Discrimination circuit

Claims (1)

[Claims] Claims: 1. A combustion control method using a combustion control circuit (2) for controlling the combustion amount of a boiler (1) in multi-steps, wherein the combustion control method is used for transition from low combustion to high combustion and for high combustion. When a misfire also occurs, the boiler combustion control method is characterized in that the boiler is restarted to forcibly continue combustion in a low combustion state.