JPH0612349Y2 - Compulsory supply / exhaust combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a forced supply / exhaust combustion device.

(Prior Art) Conventionally, in a forced air supply / exhaust type water heater, based on a feedforward control for controlling a gas amount based on a set temperature, an incoming water temperature, and a water flow rate, a set temperature and a hot water temperature. It employs feedback control to control the gas amount or gas amount control by the combined output of feedforward control and feedback control, and variably controls the gas amount using a proportional control valve, and it is predetermined according to the gas amount. The fan was controlled to the target speed.

(Problems to be solved by the device) However, in this type of combustion device, the temperature of the combustion pipe is lower for a few seconds at the beginning of combustion than in the state after that, so a little more primary air enters and blows out from the flame outlet. The gas concentration of the mixed gas becomes leaner than usual, and the ejection speed from the flame mouth becomes faster. Furthermore, because the temperature of the mixed gas that is ejected is low because the vicinity of the flame mouth is not burnt, when the combustion amount (supply air amount) or more, the flame is lifted from the flame mouth, and the flame The flame vibrates finely until it settles in the flame mouth, and the vibration of the flame resonates with the combustion tube or the body of the heat exchanger that forms the combustion chamber, and produces a whistling noise. Had the problem.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a forced air supply / exhaust type combustion device in which the generation of abnormal noise at the beginning of combustion is prevented.

(Means for Solving the Problems) In order to achieve the above object, the forced supply / exhaust type combustion apparatus of the present invention has the following configuration. That is, in a device including a proportional control valve that continuously changes the gas amount according to the load and a fan that is controlled to a predetermined target rotation speed that corresponds to the gas amount, a timer that starts after ignition detection is used. A control means is provided for controlling the rotation speed of the fan to be lower than the target rotation speed within a fixed time defined by a timer and when the gas amount is a predetermined amount or more.

(Operation) When ignition is detected, the amount of gas is controlled from the amount of gas for ignition to the amount of gas according to the load.
The rotation speed of the fan is controlled to be lower than the target rotation speed corresponding to the gas amount to offset the increase in the primary air amount caused by the low temperature of the combustion tube. The temperature of the combustion tube rises as the combustion continues, so that the fan rotation speed is controlled to the target rotation speed after a certain period of time.

(Example) The Example of this invention is described with drawing. In FIG. 1, (1) is a heat exchanger for boiling water, (2) is a water inlet pipe, and (3) is a hot water outlet pipe. The water inlet pipe (2) is provided with a flow rate sensor (4) for detecting the water flow rate, the water inlet temperature sensor (5) for detecting the water inlet temperature, and the hot water outlet sensor (3) is provided for the hot water outlet pipe (3).
(10) is provided. (7) is a proportional control valve provided in the gas supply path to the combustion pipe (8), (9) is a fan for air supply, (1)
1) is a fire sensor such as a flame rod that detects ignition of the combustion pipe (8), (6) is a proportional control valve (7), fan (9)
It is a control means for controlling the above.

In the following, referring to the control flow chart of FIG. 2, when the fire sensor (11) detects ignition of the combustion pipe (8), a timer constituted by the microcomputer (6 ') of the control means (6) is activated. Starting means and controlling means (6)
A control signal for controlling the gas amount according to the load is output from the proportional control valve (7). That is, the feedforward calculated based on the set temperature set by the hot water temperature setting device (not shown), the incoming water temperature detected by the incoming water temperature sensor (5), and the water flow rate detected by the flow rate sensor (4). The control component, the preset temperature, and the feedback control component calculated based on the hot water temperature detected by the hot water temperature sensor (10) are combined to calculate the gas amount and control the proportional control valve (7). .

The target rotational speed of the fan (9) is experimentally determined in advance as shown by the solid line in FIG. 3 in accordance with the gas amount, but it is within the fixed time defined by the timer (6 ') and When the amount of gas is equal to or greater than the predetermined amount (G), the rotation speed is controlled by subtracting a certain rotation speed (f) from the target rotation speed, as indicated by the one-dot chain line in FIG.

That is, since the temperature of the combustion pipe (8) is low at the beginning of combustion and the amount of primary air entering the combustion pipe (8) is slightly higher than usual, the fire is lifted when the combustion amount exceeds a certain level, and the lifted fire. A small amount of noise will be generated when the engine vibrates finely near the flame mouth of the combustion pipe (8), but the rotation speed of the fan (9) will be reduced to offset the increase in the primary air and lifting of a fire and abnormal noise will occur. Is prevented.

Then, after a lapse of a certain time, the temperature of the combustion pipe (8) rises, so that the rotation speed of the fan (9) is controlled to a normal target rotation speed.

(Effects of the Invention) The forced supply / exhaust type combustion apparatus of the present invention has the following excellent effects. That is, it is possible to prevent the occurrence of abnormal noise due to the lifting of the fire and the vibration of the lifting fire due to the low temperature of the combustion tube at the beginning of combustion.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is an overall configuration diagram, FIG. 2 is a control flow chart, and FIG. 3 is a relationship diagram between gas amount and fan rotation speed. (6) ...... Control means (6 ') ...... Timer (7) ...... Proportional control valve (8) ...... Combustion tube (9) ...... Fan

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Liangda 32 Akashi-cho, Chuo-ku, Kobe, Hyogo Pref. Hitoshi Maeda, Examiner, Noritsu Co., Ltd. (56) References: 62-39138 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A device comprising a proportional control valve for continuously varying a gas amount according to a load, and a fan controlled to a predetermined target speed corresponding to the gas amount,
A timer for starting after ignition detection is provided, and a control means is provided for controlling the rotation speed of the fan to be lower than the target rotation speed within a fixed time defined by the timer and when the gas amount is a predetermined amount or more. A forced supply / exhaust combustion device characterized by the above.