JPH0210345B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a combustion device that burns fuel using a burner. In conventional combustion apparatuses, the amount of combustion is controlled by analog control of the amount of fuel and air supplied by adjusting the opening degrees of valves, and the control system is complicated. Also, with conventional burners, it is difficult to achieve a large turndown ratio.
It was not possible to control combustion in a range where the amount of combustion was small. An object of the present invention is to provide a combustion device in which the amount of combustion can be easily adjusted, the turndown ratio of the burner can be increased, and the temperature can be precisely controlled. The present invention provides a burner having a plurality of flame holes, the plurality of air supply pipes that individually supply combustion air to each flame hole, and the plurality of air supply pipes that individually supply fuel to each flame hole. A supply pipe, an air control valve provided in the middle of each air supply pipe, a fuel control valve provided in the middle of each fuel supply pipe, and an air control valve and a fuel control valve corresponding to any flame hole at the same time. The combustion amount of each of the plurality of flame holes is N, 2N, 2 ² N, ..., 2 ^m , where N is the combustion amount of the minimum flame hole and m is the number of flame holes. ^-1 N to a power of 2, and the opening/closing control means controls a total of 2 ^m types of combinations of simultaneous opening and closing of the air control valve and the fuel control valve. . Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an embodiment of the present invention.
The burner 2 attached to the combustion furnace 1 shown by the imaginary line has a plurality of flame holes h, for example, first to fifth flame holes h.
1, h2, h3, h4, and h5 are formed.
First to fifth fuel supply pipes F1, F2, F3, F4, F5 are individually connected to each flame hole h1 to h5, and first to fifth air supply pipes A1, A
2, A3, A4, and A5 are individually connected. The first to fifth fuel supply pipes F1 to F5 are connected to a fuel supply source 4 via a common pipe line 3, and the first to fifth fuel supply pipes F1 to F5 are
The fifth air supply pipes A1 to A5 are connected to an air supply source, for example a forced air blower 6, via a common pipe line 5. Combustion in each of the flame holes h1 to h5 in the burner 2 is controlled on and off by a control means 7 based on, for example, a detected value of a temperature detector 8 that detects the temperature inside the furnace. First to fifth fuel control valves FC1 to FC5 are provided in the middle of each fuel supply pipe F1 to F5, respectively. These fuel control valves FC1 to FC5 are, for example, electromagnetic valves. Further, first to fifth air control valves AC1 to AC5 are provided in the middle of each of the air supply pipes A1 to A5, respectively. These air control valves AC1~
AC5 is, for example, a solenoid valve. The combustion amount in each flame hole h1 to h5 in burner 2, that is, each fuel control valve FC1 to FC5 and each air control valve AC
The combustion amount when the valves 1 to AC5 are opened is set to a power of 2 as shown in Table 1.

[Table] In Table 1, the symbol N indicates the unit combustion amount, that is, the combustion amount of the smallest flame hole. The control means 7 controls the opening and closing of each of the control valves FC1 to FC5 and AC1 to AC5 corresponding to the same flame holes h1 to h5, for example, in accordance with the temperature detection value of the temperature detector 8. In this way, 32 types of combustion states can be arbitrarily set as shown in Table 2 by combining the control valves to be opened and closed.

【table】

[Table] As shown in Table 2, the 32 combustion states from S1 to S32 can be changed arbitrarily, so the temperature inside the furnace can be precisely controlled in steps as shown in Figure 2. can. In other words, the range between the upper limit of the proportional band shown by line l2 above the set value shown by line l1 and the lower limit of the proportional band shown by line l3 below line l1 is divided into 32 steps for precise control. Can be done. Moreover, the turndown ratio in burner 2 can be set to a relatively large value of 1:13. In the above embodiment, the first to fifth flame holes h1 to h5
Although described in connection with a burner having a plurality of flame holes, the present invention can be broadly practiced in connection with a burner having a plurality of flame holes. Further, in the above embodiment, the explanation has been made in relation to a so-called premix burner that mixes air and fuel in each flame hole h1 to h5, but in the present invention, each flame hole h1
It can also be implemented in conjunction with a so-called pre-mix burner that feeds h5. As described above, according to the present invention, the supply of fuel and air to each flame hole of the burner is controlled on and off in a state adjusted for each preset combustion amount, so that the combustion amount of the burner as a whole can be controlled over a wide range. can be easily and stably adjusted, and the turndown ratio of the burner can be made relatively large. Moreover, since the combustion amount of each flame hole is set in a power-of-two relationship, the combustion amount can be varied for each N over a wide range. In particular, since stable and wide-range control is possible even in large combustion furnaces, the temperature inside the furnace can be easily controlled.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIG. 2 is a diagram for explaining step control. 2... Burner, h1~h5... Flame hole, F1~F
5... Combustion supply pipe, A1 to A5... Air supply pipe,
FC1 to FC5...Fuel control valve, AC1 to AC5...
Air control valve.

Claims (1)

[Scope of Claims] 1. A burner having a plurality of flame holes, the plurality of air supply pipes that individually supply combustion air to each flame hole, and the plurality of air supply pipes that individually supply fuel to each flame hole. a fuel supply pipe, an air control valve provided in the middle of each air supply pipe, a fuel control valve provided in the middle of each fuel supply pipe, and an air control valve and a fuel control valve corresponding to any flame hole. The combustion amount of each of the plurality of flame holes is N, 2N, 2 ² N,..., where N is the combustion amount of the minimum flame hole and m is the number of flame holes. 2 ^m-1 N to a power of 2, and the opening/closing control means controls a total of 2 ^m combinations of simultaneous opening and closing of the air control valve and the fuel control valve. .