JPS60174422A - Gas combustion control device - Google Patents

Abstract

PURPOSE:To control a ratio of primary air to obtain a substantial constant value by a method wherein a mechanism for varying an inner diameter of float for use in adjusting automatically an inner diameter of a throat is arranged at a venturi pipe mixing part in response to an increasing and decreasing of combustion volume. CONSTITUTION:In case of a maximum combustion volume, a heat value received by a heat sensitive body 17 is high and either liquid or gas 16d is expanded, so that a flexible material 16b such as rubber is deformed as indicated by a broken line A. That is, it acts to reduce a diameter of the throat at the venturi pipe mixing part. As the heat value of combustion is gradually decreased from this condition, the heat value received by the heat sensitive body 17 is also decreased, so that a flexible material 16b such as rubber is deformed gradually from a condition A toward a direction where a diameter of the throat is expanded. With this arrangement, it is made possible to control the ratio of primary air to show substantially constant value, thus, it is made possible to realize a combustion unit having a wide range of adjustment in heat value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a waste combustion control device that improves the air-fuel ratio control characteristics, particularly the primary air ratio, in accordance with the combustion characteristics of...

Conventional Structure and Problems Conventionally, a cello governor type is well known as a waste combustion control device for this bucket. Since this method uses a mechanical governor, large frictional forces and hysteresis occur in the valve parts and other parts, and as a result, control errors become large, especially when the combustion angle is lowered. There was a problem in that the combustion adjustment range could not be widened.

On the other hand, instead of a mechanical governor, there is a control 1iII/ζ gas combustion control device that uses differential pressure sensors, gas pressure proportional control valves, etc. and has excellent control accuracy. The example (not publicly known) is shown in the 11th
1A is the air side 1[ that supplies combustion air, unless shown in
When flowing at a predetermined pressure, , an adjustable type gas nozzle formed with TF4 so that the opening degree of the throttle can be variably adjusted according to the type of gas, 4 a blower that supplies the necessary air for combustion, 5 a mechanism for variably controlling the rotational speed of the blower 4. 6 is a primary air passage, 7 is a secondary air passage, 8 is a white variable air throttle that determines the primary air volume at the rated input, and 9 is a means for mixing gas and air with low pressure loss. This is a 7-shape mixing section constructed in the shape of a Pencilly tube.

Reference numeral 10 denotes a variable 2'r-order air damper for the secondary air rate adjustment Mij disposed in the secondary air trace path 7, and is adjusted in accordance with the gas type using the rotation of l □ a +1ill+ as a fulcrum. 11 is a differential pressure sensor that detects the pressure difference on the upstream side between the adjustable gas nozzle and the variable primary air restrictor; 12 is an electric control unit that receives the signal from the differential pressure sensor 11 and controls the gas amount and the adjusting means 2; .

13 is the bar, 14 is the heat exchanger.

Air-fuel ratio control in this more I'tlt configuration
, v:l so that the pressure difference between the blowing pressure PA of the blower 4 corresponding to the load (that is, the pressure on the upstream side of the variable primary air restrictor 8) and the upstream pressure PG of the adjustable cast nozzle 3 becomes zero. , PA and P (3) is constantly detected by a differential pressure sensor 11 to control the gas amount adjusting means 2 to control the air-fuel ratio to be constant even when the combustion amount is changed. .

By the way, in this case, in the case of an all-primary air type burr that mixes all the amount of air required for complete combustion as primary air, the air-fuel ratio remains constant even if the combustion amount is changed by 1°. However, in the case of a Bunsen burner that supplies primary air and secondary air separately, the air-fuel ratio, especially the primary air ratio, cannot always be controlled at a constant level.
Although it depends on the characteristics of No. 3, as shown in FIG. 2, the primary air ratio tends to decrease in the low combustion region, and the characteristics tend to differ depending on the gas type. (a, 1),
(C indicates a different gas type) Therefore, depending on the combustion characteristics of Bar 13, the stable combustion range is limited accordingly, making it impossible to widen the combustion range (for example, with propane gas, the primary air ratio decreases) This results in a yellow flame, which makes complete combustion difficult.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to improve the air-fuel ratio control characteristics, especially the primary air ratio, and expand the control range of the combustion amount.

Structure of the Invention The present invention includes a differential pressure sensor that detects the pressure difference between the upstream side of the adjustable gas nozzle and the upstream side of the variable primary air restriction, and uses the output of this differential pressure sensor to detect the gas-1a-rJrrI node means. Either one of the air amount adjusting means is configured to be controlled by an electric control unit 11, and the primary air meter necessary for combustion and the secondary air flow are controlled by an adjustable gas nozzle. The system is configured with a variable primary air throttle, a variable secondary air damper, and a throat internal diameter variable mechanism built into the throat of the mixing section that mixes gas and air.

With this configuration, even when the combustion needle is adjusted, the primary air ratio of the burner remains constant.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. S, 4, and 5.

In FIGS. 3 and 4, the same components as those in FIG. 1 are designated by the same numbers and their explanations are omitted.

9a is a throat portion, and 15 is a combustion chamber, which are disposed below the burner 13. 16 is a throat inner diameter variable mechanism disposed in the throat part 9a of the ventili tube shape mixing part, and the casing 16a is made of a flexible material 1i11 (3) such as rubber.
b, a tightening ring 16C, etc. The inside of the casing 1621 is filled with a liquid or gas body 1 (1) that expands and contracts with heat. 17 is a temperature sensing element connected to the throat inner diameter "J changing mechanism 16 and the impulse pipe 18. , is arranged in the combustion chamber 15. 19 is Q9
There is a...

In the above configuration, as in the conventional case, when the combustion amount changes, the upstream pressure PA of the variable primary air throttle 8 and the upstream pressure PG of the adjustable gas nozzle 3 are controlled to be equal.

In the case of the maximum combustion amount, since the amount of heat received by the heat sensitive body 17 is large, the liquid or gas body 16 (1) expands, so the flexible material 16b such as rubber is shown by the broken line A in Figure 4. In other words, it acts to narrow the throat diameter of the Pencilly tube-shaped mixing section.

If you gradually reduce the amount of combustion from a state like this,
Since the contemplation received by the heat sensitive body 17 also decreases, the flexible material 161, such as rubber, deforms from the state A gradually in five directions (slow 1, diameter expands).

Therefore, when the throw 1 diameter increases, the throw 1 part 9
The flow velocity flowing through a decreases, that is, the suction effect of the dregs by the primary air filter decreases, making it difficult for gas to enter.

Therefore, the amount of air increases until the specified amount of gas enters. <4 Since it is controlled to be large, the -order air ratio increases, resulting in low air ratios as shown in Fig. 5, a', b', and C' (characteristics differ slightly depending on each gas type). The combustion zone is corrected to increase the primary air ratio, and this primary air ratio can be controlled to be constant throughout the combustion range.

Effects of the Invention As described above, according to the gas combustion control device of the present invention, by disposing a throat inner diameter variable mechanism that automatically varies the throat inner diameter in the ventili tube shape mixing section in response to an increase or decrease in the combustion amount. , Even if you adjust the combustion amount, the primary air ratio remains unchanged.
can be controlled precisely.

However, since it is possible to set the burner to be within the stable combustion limit, it is possible to realize a combustion device with a wider range of combustion amount adjustment than in the past.

[Brief explanation of the drawing]

Fig. 1 is a block diagram including a partial cross section of a conventional gas combustion amount a14) device, Fig. 2 is a control characteristic diagram of the conventional device, and Fig. 3
FIG. 4 is an enlarged cross-sectional view of the throat portion of the ventili tube-shaped mixing section of the device, and FIG. 5 is a diagram showing the control characteristics of the device. 1q...Cast side passage, 1 person...Air side passage,
2...Gas amount adjustment means, 3...d same cylinder type gas nozzle, 4...Blower, 5...Air amount adjustment means, 6...Primary air 11n road, 7...2
Secondary air passage, (... variable primary air throttle, 9.
Mixing part, 9a...Throat part, 10...1 change 2
Next Air tamper, 11...Differential pressure sensor, 12...
...Electric control section, 15... Combustion chamber, 16...
Throw 1/Inner diameter variable mechanism, 17...Temperature sensing element. Name of agent: Patent attorney Toshio Nakao (and 1 other person) 1st! A Figure 2, Boundary 1 Figure 3, 12

Claims (3)

[Claims] (1) The gas side passage is provided with a gas amount adjusting means and a regulating gas nozzle, and the air side passage is provided with a blower for supplying combustion air and an air singling adjustment means, and the downstream of this blower is used as the primary air passage. It branches into a secondary air passage, and the primary air passage includes:
A variable primary air restrictor and a Venturi tube-shaped mixing part for mixing gas and air are arranged at the downstream of the variable primary air restrictor and the adjustable gas nozzle, and a throat part of this mixing part is provided. A throat inner diameter iJ' variable mechanism is built-in, and the secondary air passage is provided with an ijJ variable secondary air damper compatible with the gas ridge, and the flow pressure of the adjustable gas nostle and the variable primary air throttle are disposed in the secondary air passage. A differential pressure sensor that outputs an electrical signal corresponding to a pressure difference between the upstream pressure of Gas combustion control device consisting of parts. (2) The gas combustion control device according to claim 1, wherein the inner diameter variable portion of the throat inner diameter variable mechanism is made of a combustible material. (3) The gas according to claim 1 or 2, wherein a temperature sensing element is disposed within the combustion chamber, and the throat inner diameter variable mechanism is driven in conjunction with the action of the temperature sensing element. Combustion control device.