JP2563532B2 - Gas combustion amount control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas combustion amount control device capable of electrically controlling the combustion amount of a gas burner.

2. Description of the Related Art Conventionally, a gas combustion amount control device of this type has a configuration as shown in FIG. 5, for example. That is, a burner nozzle 5 that supplies gas to a burner 4 is disposed downstream of a solenoid valve 2 that opens and closes a gas passage 1 of a gas combustion device via a gas proportional valve 3, and a solenoid valve 2 is controlled by a controller 6. In addition, a configuration in which the gas proportional valve 3 is electrically controlled is generally conventional. FIG. 6 shows a configuration diagram of a conventional gas proportional valve 3. A valve seat 9 which is an elastic member provided between the gas inlet 7 and the gas outlet 8 and a valve body 10 facing the valve seat 9 are provided, and the valve body 10 is fixed to the valve body 10 to exert a force in the valve closing direction by the gas pressure. A gas governor portion composed of a diaphragm 11 that acts on the valve, a spring 12 that gives a closing force to the valve body 10, and a coil that is an electromagnetic force generation portion that generates an electromagnetic force by an electric signal from the controller 6.
13, a yoke 14, which is a magnetic body, and a plunger 15.

Conventionally, in such a configuration, in the gas combustion device, the solenoid valve 2 is opened by a signal from the controller 6 at the time of ignition, and
The gas proportional valve 3 is also opened to supply gas to the burner nozzle 5,
It is ignited by an igniter (not shown) and combustion is started by the burner 4. Then, the signal from the controller 6 causes the gas proportional valve 3 to generate an electromagnetic force proportional to the current value of the coil 13 in the plunger 15 and transmit the electromagnetic force to the valve body 10. This electromagnetic force causes the spring
While overcoming 12 and opening the valve body 10, a secondary pressure proportional to the electromagnetic force is obtained by the governor principle. Therefore, an arbitrary burner nozzle pressure is obtained by the electric signal, and the gas combustion amount of the burner 4 can be varied.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above configuration, the burner nozzle 5
Since the flow passage area of the gas passage 1 up to is changed by squeezing or opening with the gas proportional valve 3, the valve seat 9 of the gas proportional valve 3 must be formed with a large diameter. . This is because a predetermined burner nozzle pressure must be secured in order to secure the maximum rated combustion amount of the gas combustion equipment, and therefore the flow path pressure loss is not the gas proportional valve 3 with a small pressure loss of about a few millimeters of water. This is because it must not happen. In addition, the fact that the valve seat 9 of the gas proportional valve 3 has a large diameter as described above requires that the actuator for adjusting the opening degree of the valve seat 9 has a large stroke and a large operating force. This is because the large-diameter saturated stroke inevitably becomes larger than the small-diameter stroke, and the larger the diameter, the larger the gas pressure acting area and the larger the force required to drive the valve body 10. The above contents make the gas proportional valve 3 large and expensive. As a result, it will hinder the downsizing and cost reduction of the gas combustion equipment itself. This has been an undesired problem, while it is desired to make the device lighter, thinner, shorter, smaller, and cheaper.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas combustion amount control device capable of electrically varying the gas combustion amount with an actuator having a small stroke and a small actuation force.

Means for Solving the Problems To solve the above problems, the gas combustion amount control device of the present invention is a burner nozzle that ejects gas to a burner, a passage that guides the gas to the burner nozzle, and an on-off valve that opens and closes the passage, A flow rate varying means for electrically varying the flow passage area of the nozzle hole itself of the burner nozzle to control the amount of gas jetted and supplied to the burner is provided.

Effect Since the present invention controls the amount of gas jetted and supplied to the burner by electrically varying the flow passage area of the nozzle hole itself with the above configuration, the gas combustion charge can be electrically varied by an actuator with a small stroke and small operating force. Since the amount of gas is controlled by the nozzle hole itself, the gas does not have to be ejected after the pressure drops once on the upstream side of the nozzle hole, unlike the case of controlling the amount of gas in the middle of the flow path. Even in such a case, the ejector effect is surely exhibited, and good combustion can be secured.

Embodiment One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a basic configuration of a gas combustion amount control device such as a gas table and a gas water heater for home use according to an embodiment of the present invention. An opening / closing valve 17 is provided in a gas passage 16 and a downstream end thereof is provided. A burner nozzle 19 whose flow passage area can be varied by an electric signal from the controller 18 is connected to control the amount of gas jetted and supplied to the burner 20.

Since the gas combustion amount is adjusted by electrically changing the flow passage area of the burner nozzle 19, the electric actuator for changing the flow passage area of the burner nozzle 19 need only have a small stroke and small operating force. That is, the hole diameter of the burner nozzle 19 is
Since it is extremely small compared to the passage diameter that guides the gas to the burner nozzle, the valve stroke required to change the passage area of the burner nozzle 19 reaches a saturation stroke with an extremely small valve stroke, that is, the passage area corresponding to the hole diameter of the burner nozzle 19 is reached. I will end up. Therefore, a small stroke actuator is sufficient. In addition, the actuating force required for the actuator is extremely small because the acting force of the fluid that acts on the valve element that closes or opens a small hole diameter is extremely small, so the actuator actuating force for operating the valve element by overcoming that acting force is also extremely small. Complete. This is because the product of the operating area and the gas pressure is the operating force, but since the burner nozzle diameter is extremely smaller than the passage diameter that guides the gas to the burner nozzle, the operating area is small and the valve body is operated to overcome the operating force. Therefore, the actuator operating force of is also extremely small.

Therefore, since an electric actuator having a large stroke and a large actuation force is not required unlike the conventional case, the actuator can be made extremely small and a small and inexpensive gas combustion amount control device can be realized.

FIG. 2 is a diagram showing in more detail in the vicinity of the burner nozzle 19 of the gas combustion amount control device as one embodiment shown in FIG. 1 of the present invention. A needle valve body 23 is provided so as to face the inside of a nozzle hole 22 formed in a brass nozzle tip 21, and the nozzle tip 21 is screwed with a needle guide 24 formed of a non-conductive ceramic. The needle guide 24 has a cross-sectional shape as shown in FIG. 3, and has three ribs 25 on the inner surface.
The needle valve element 23 is slidably guided by the rib 25, and the space 26 between the rib 25 serves as a gas passage. Note that FIG. 3 is a dashed-dotted line AA in FIG.
It is the figure which showed the cross section of a part. Also, the threaded portion of the nozzle tip 21
A sealing material is applied to 27, and the screw portion 27 is sealed so that gas does not leak regardless of how tight the screw is. The other end of the needle guide 24 has a gas passage.
An aluminum pipe joint 28 communicating with 16 is screw-fastened. Further, a brass fixing plate 29 is sandwiched and fastened between the needle guide 24 and the pipe joint 28, and the fixing plate 29 is provided with a vent hole 30 for passing gas therethrough. Further, between the needle valve body 23 and the fixed plate 29, a thin linear Ti-Ni-based shape memory alloy wire 31 having a wire diameter of 0.15 mm is mechanically caulked and fixed at both ends. A bias spring 32, which is a stainless steel compression spring, is attached to the outside of the alloy wire 31, and the needle valve body 23 is attached to the nozzle hole 22.
Is urged in the direction of closing. An insulating film 33 is formed at the contact portion so that the fixed plate 29 and the bias spring 32 are electrically insulated.

When a voltage is applied to the nozzle tip 21 with the above configuration, a current flows from the nozzle tip 21 through the shape memory alloy wire 31 to the fixing plate 29 and further to the pipe joint 28, and the shape memory alloy wire 31 self-heats by energization, that is, energization heating. To be done. When the shape memory alloy wire 31 before electric heating is lower than the transformation temperature, the shape memory alloy has a very soft martensite structure, so the shape memory alloy wire 31 is stretched by the force of the bias spring 32 and the needle valve element 23 is opened in the nozzle hole. It is energized in the direction to block 22 and is in the state of blocking the flow of gas or keeping it at the minimum flow rate. When the shape memory alloy wire 31 is energized and heated, it transforms into an austenite structure and contracts to return to a constant flow that is stored in advance, so the needle valve body 23
Acts to open the nozzle hole 22. The shape memory alloy wire 31 used in this example had a transformation temperature of about 70 ° C.
Shape memory alloy wire accompanying the above heating / cooling thermal cycle
The change in length of 31 will be described with reference to FIG. 4. First, in the case of a soft martensite structure such as nylon wire in a low temperature state, it is stretched by the bias spring 32 and is in a long state. Next, when electrically heated, the internal crystal structure starts to change into an austenite structure. This is the point indicated by the symbol "As" in FIG. Upon further heating, the entire internal crystal structure completes the austenite transformation at the point of Af. In this state, the shape memory alloy wire 31 has the shortest length in a state where the state has completely shrunk to a certain length which has been memorized.
In the high temperature austenite state, it has rigidity and rigidity like a piano wire, and the contracting force at this time can generate a force sufficiently larger than the force of stretching and deforming at the low temperature. When cooled from a high temperature austenitic state, Ms
From this point, the internal structure begins to transform into martensite, and the length of the shape memory alloy wire 31 begins to be stretched by the bias spring 32. When further cooled, the entire internal crystal structure completes the martensitic transformation in terms of Mf. As described above and as shown in FIG. 4, the shape memory alloy wire 31 of FIG. 2 functions to shrink when heated and to relax when cooled, and although there is some hysteresis, the shape memory alloy wire 31 is shown.
Since the length depends on the temperature, the drive amount of the needle valve element 23 can be controlled according to the amount of electric heating. That is, by controlling the amount of electric heating by the controller 18,
The gas flow rate of the burner nozzle 19 will be controlled. First
With the configuration of one embodiment of the present invention as shown in the figure, the burner nozzle 19 can be operated by an actuator with a small stroke and a small operating force.
By making it possible to change the flow passage area of the actuator, the actuator can be made into a linear and thin shape memory alloy wire as shown in FIG.
With 31, a sufficient force and stroke can be obtained. Although it is a shape memory alloy as described above, it is linear and short and has an extremely thin wire diameter of 0.15 mm, so the heat capacity can be made extremely small, and high-speed response can be obtained.
A unique effect is obtained in that the power consumption can be as low as watts. By the way, the conventional gas proportional valve 3 required an electric power of about 8 watts, which is about 16 times as much. If the actuator of the gas proportional valve 3 of the conventional gas combustion amount control device as shown in FIG. 5 is made of a shape memory alloy,
In terms of required force and stroke, the wire diameter will first be 1 mm or more and the shape will be a coil spring shape rather than a straight line. However, in that case, the heat capacity becomes large and the response speed is slow, which is not practical. In the case of the configuration of the embodiment as shown in FIG. 2, since the shape memory alloy wire 31 may be an extremely thin and short straight line, there is an effect that the amount of the shape memory alloy material used is very small and the cost can be reduced. Further, since the shape memory alloy wire 31 is configured in the gas passage of the burner nozzle 19, the shape memory alloy wire 31 is linearly cooled by the gas flow,
There is an effect that a faster response speed can be obtained. Further, in the configuration of the embodiment as shown in FIG. 2, as described above, the shape memory alloy wire 31 is contracted by the self-heating by energization, the needle valve body 23 is pulled, and the opening degree of the nozzle hole 22 is increased. Then, the gas flow acts to increase the gas flow rate, and the gas flow acts to cool and relax the shape memory alloy wire 31 to reduce the opening degree of the nozzle hole 22 by the needle valve body 23. That is, the shape memory alloy wire 31 stabilizes at a temperature at which heating by energization and discharge by a gas flow are suspended, and settles to a length corresponding to the temperature. An example will be described with reference to FIG. 4. When a certain constant voltage is applied to the nozzle tip 21, the shape memory alloy wire 31 is heated and first contracts to a length indicated by a point B to increase the gas flow rate. Then, the cooling effect of the shape memory alloy wire 31 increases as the gas flow rate increases, and when the temperature slightly decreases, the heating and the heat dissipation are balanced and settle at the point C. Therefore, by configuring the shape memory alloy wire 31 for varying the flow passage area of the burner nozzle 19 in the gas passage in this manner by electrically heating, it operates on a substantially small hysteresis loop, and a shape having a large hysteresis. Even with the memory alloy, the gas flow rate can be controlled relatively accurately. Furthermore, the burner nozzle is heated by electric heating.
By configuring the shape memory alloy wire 31 that varies the flow path area of 19 in the gas passage, when the gas supply pressure at the inlet side of the device fluctuates, for example, when the supply gas pressure fluctuates and becomes high, the gas flow rate increases. When the shape memory alloy wire 31 is cooled and relaxed, the needle valve body 23 moves in the direction of decreasing the opening of the nozzle hole 22, and when the supply gas pressure fluctuates to the lower side, the gas flow rate decreases and the shape memory It becomes difficult to cool the alloy wire 31, and the needle valve body 23 moves in the opening direction. In this way, a kind of feedback loop is formed to balance the heating by energization and the cooling by the gas flow, and it has a function like a so-called flow governor to keep the gas flow rate according to the applied voltage or current. effective. Further, as described above, in the configuration of the embodiment of the present invention, by configuring the gas flow area of the burner nozzle 19 to be electrically variable to control the gas flow rate, an actuator can be formed inside the burner nozzle 19. Moreover, since it is small in size, it has no external appearance, and it has a peculiar effect that it can be configured into a device so neatly as to not know where the mechanism for controlling the gas amount is. Further, the burner nozzle 19 is also configured to control the gas flow rate by electrically varying the gas flow passage area of the burner nozzle 19 so that the burner nozzle can be used for gas species conversion.
It is sufficient to replace the 19th part, and the gas species can be converted in the same way as the conventional nozzle replacement. There is no need to remove the burner nozzle 19 of the gas flow path terminal and replace it by removing the flow path in the gas pipe of the device. Further, although an example in which a shape memory alloy is mainly used as an actuator has been described as one embodiment of the present invention described above, it is not limited to the shape memory alloy, and strain and force are generated by voltage instead of the shape memory alloy. Even if a piezoelectric element is used, the gas flow rate can be changed electrically at a low cost in a similar manner. Alternatively, a small electromagnetic coil is formed in the portion of the needle guide 24, and the needle valve body 23 is formed of a magnetic material such as iron or stainless steel.A so-called electromagnetic actuator is similarly small and compact, and the gas flow rate is electrically reduced at a low cost. A variable effect can be obtained.

Further, in the gas combustion equipment, it is important to successfully suck the primary air together with the gas into the burner by the ejector effect by the gas ejection energy of the burner nozzle, but the structure of the present invention, that is, the flow passage area of the burner nozzle 19. The configuration in which the air is electrically variable has a unique effect that the primary air suction characteristic is very excellent. This is because the flow passage area in the middle of the gas passage 1 is changed to the gas proportional valve 3
When the gas flow rate is varied by squeezing with, the gas pressure has already dropped immediately after the gas proportional valve 3, so the burner nozzle 5
However, since the gas pressure is further reduced, the flow velocity of the gas ejected from the hole of the burner nozzle 5 having a constant diameter is slow, and therefore the ejector effect is small, so that the suction characteristic of the primary air is inferior. In contrast, in the case of a configuration in which the flow passage area of the burner nozzle 19 is electrically changed as in the present invention, there is no gas proportional valve in the middle of the gas passage 16,
Since the flow area of the burner nozzle 19 that is the end of 16 is narrowed to change the gas flow rate, the gas pressure of the burner nozzle 19 can be kept higher than before, and the gas ejection speed can be sufficiently high, and therefore sufficient. It has a unique effect that it is easy to secure a special ejector effect, has excellent primary air suction characteristics, and produces less incomplete combustion and soot.

Effects of the Invention As described above, the gas combustion amount control device of the present invention has the following effects.

(1) Since the flow passage area of the nozzle hole itself of the burner nozzle is electrically changed, the gas combustion amount can be changed by an actuator with an extremely small stroke and small operating force, and the size, cost and power consumption can be reduced. You can

(2) Since the flow passage area of the nozzle hole itself of the burner nozzle is made variable, the gas is ejected after the pressure once drops on the upstream side of the nozzle hole as in the case of controlling the gas amount in the middle of the flow passage. Is eliminated, the ejector effect is surely exhibited even when the gas amount is small, and good combustion can be secured.

(3) Since the amount of gas is controlled just before the burner nozzle nozzle hole, that is, immediately before the burner, the combustion amount can be controlled with extremely high responsiveness.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas combustion amount control device according to an embodiment of the present invention, FIG. 2 is a front sectional view in the vicinity of a burner nozzle of the gas combustion amount control device, and FIG. 3 is a burner nozzle of the gas combustion amount control device. 2 is a sectional view taken along the line AA in FIG. 2, and FIG. 4 is an explanatory view of the operation of the burner nozzle of the gas combustion amount control device.
FIG. 5 is a configuration diagram of a conventional gas combustion amount control device, and FIG. 6 is a front sectional view of a gas proportional valve of the conventional gas combustion amount control device. 16 …… passage, 17 …… open / close valve, 18 …… controller, 19 …… burner nozzle, 20 …… burner.

Claims (3)

(57) [Claims] 1. A burner nozzle for ejecting gas to a burner,
A passage that guides gas to the burner nozzle, an on-off valve that opens and closes the passage, and a flow rate varying unit that electrically varies the flow passage area of the nozzle hole of the burner nozzle to control the amount of gas jetted and supplied to the burner. A gas combustion amount control device equipped. 2. The flow rate varying means comprises a needle valve body provided so as to vary the flow passage area of the nozzle itself, and an electric drive means for electrically driving the needle valve body.
The gas combustion amount control device described. 3. The electric drive means comprises a bias spring for urging the needle valve element in the closing or opening direction, a shape memory alloy for driving the needle valve element in the opening or closing direction by electric heating, and a shape memory alloy of the shape memory alloy. The gas combustion amount control device according to claim 2, further comprising a controller that controls an amount of electricity supplied.