JP3750061B2 - Gas flow control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas flow rate control device used for a gas cooking appliance such as a gas stove.
[0002]
[Prior art]
This type of gas flow control device has a gas passage connected to a gas injection nozzle connected to a mixing pipe of a gas burner, and the gas passage is driven by, for example, a geared motor to change the opening of the gas passage A flow rate adjusting means is provided.
[0003]
A pressure sensor, which is a secondary pressure detecting means for detecting the secondary pressure of the fuel gas, is provided in the gas passage upstream of the flow rate adjusting means and downstream of the gas injection nozzle. When this gas flow control device is installed in a gas stove, for example, to adjust the set thermal power of the gas burner, the secondary pressure detected by the pressure sensor matches the target secondary pressure previously stored in the microcomputer by the microcomputer provided in the gas stove. The motor is feedback-controlled to adjust the opening degree of the flow rate adjusting means (for example, see Patent Document 1).
[0004]
By the way, when controlling the driving means so that the secondary pressure detected by the pressure sensor matches the target secondary pressure, the driving means may be repeatedly rotated forward and backward due to a difference in response speed between the driving means and the pressure sensor. Yes, it takes time to control until they match.
[0005]
In this case, it is conceivable to slow down the rotation speed of the driving means. However, this slows down the change rate of the gas flow rate, so that the change in the fire power of the gas burner in response to the cook's fire power change instruction is slowed down. Becomes worse. For this reason, in the above, it has been proposed that the speed of the driving means is quickly reduced from the magnitude of the gas pressure changing by changing the set heating power (see, for example, Patent Document 1).
[0006]
[Patent Document 1]
JP 2001-56118 A (No. 6-7, FIG. 14)
[0007]
[Problems to be solved by the invention]
However, when the driving means is driven after determining whether or not to increase the speed of the driving means in response to the cook's heating power change instruction, the heating power of the gas burner is not immediately changed, and the cooking power change of the cooker is not performed. Responsiveness to instructions is poor.
[0008]
Further, for example, even when it is necessary to rapidly reduce the heating power of the gas burner before the spilling occurs, in the above case, if the amount of change in the gas pressure does not reach a predetermined value, the rotation speed of the driving means is reduced. Since it is not accelerated, it may not be possible to prevent the occurrence of spilling, which is inconvenient.
[0009]
Therefore, in view of the above-mentioned problems, the present invention provides a gas flow rate control device that improves the usability of a gas appliance by changing the heating power of a gas burner quickly in response to a cook's heating power change instruction. It is to be an issue.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the gas flow rate control device of the present invention has a gas injection nozzle at the tip, and changes the opening of the gas passage to the gas burner for supplying fuel gas to the gas burner. A gas flow rate control device comprising a throttle part for adjusting the gas flow rate of the gas, a gas burner, and a secondary pressure detecting means for detecting a secondary pressure of the fuel gas in the gas passage between the throttle part. When a plurality of openings are set in advance, and the opening of the gas passage is changed from the current opening to the selected target opening by driving the throttle unit, the predetermined position until the target opening is reached is set. A switching position is set, and when the opening degree reaches the switching position, the preset secondary pressure corresponding to the target opening degree and the secondary pressure detected by the secondary pressure detecting means are made to coincide with each other. Switching to feedback control to control the opening The features.
[0011]
According to the present invention, when one of the target openings of the gas passages set in advance is selected, the throttle unit is driven to change the opening of the gas passage. In this case, since the throttle part is feedforward controlled to the switching position, the opening degree of the throttle part can be changed without depending on the secondary pressure of the gas passage, so the opening degree changing speed of the throttle part can be increased. .
[0012]
When the opening degree reaches the switching position, the throttle unit is switched to feedback control. Then, the opening degree is controlled so that the preset secondary pressure set in advance corresponding to the target opening degree and the secondary pressure detected by the secondary pressure detecting means coincide with each other, and a predetermined gas flow rate is supplied to the gas burner. Supplied.
[0013]
Further, if the opening degree changing speed of the throttle portion is made faster than the switching position to the target opening degree until the switching position is reached, the gas burner can be rapidly used, for example, before spilling occurs. When it is necessary to reduce the heating power, the gas flow rate is quickly changed.
[0014]
In addition, the said aperture | diaphragm | squeezing part is provided with the motor which can be rotated and stopped to a predetermined rotation angle, for example, and should just set a target opening degree and a switching position with a rotation angle.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2, reference numeral 1 denotes a gas flow rate control device according to the present invention provided in, for example, a gas stove. The gas flow rate control device 1 has a device main body 12 having a gas passage 11 connected to a gas injection nozzle (not shown) connected to a mixing tube of a gas burner provided in a gas stove. A gas valve 2 that adjusts the flow rate of the fuel gas to the gas injection nozzle is provided on the lower surface of one end of the apparatus main body 12.
[0016]
The gas valve 2 has a valve casing 22 provided with an internal passage 21 communicating with the gas passage 11, and a gas inlet 23 communicating with the internal passage 21 is opened on the upper surface of the valve casing 22.
[0017]
A stepping motor 3 having a rotation angle detecting means 31 is connected to the lower surface of the valve casing 22, and one end of a rotating shaft 32 of the motor 3 protrudes into the internal passage 21 via a seal material 33.
[0018]
The internal passage 21 is positioned upstream of the gas outlet 23 and connected to one end of the rotary shaft 32, and is fixed above the rotary disk 4 and fitted to the valve casing 22. A disk 5 is provided. The rotating disk 4 and the fixed disk 5 connected to the motor 3 constitute a throttle part, and the opening of the passage area of the internal passage 21 is changed by the throttle part to adjust the gas flow rate to the gas injection nozzle.
[0019]
As shown in FIG. 2, the fixed disk 5 has four holes 51, 52, 53, 54, which are first communication holes, formed on the same circumference with different opening areas. Other holes 52, 53, 54 other than the first hole 51 for determining the minimum gas flow rate are formed continuously.
[0020]
The rotating disk 4 has one ellipse that allows the communication between the internal passage 21 and the gas passage 11 so as to coincide with the holes 51, 52, 53, 54 of the first communication hole when the rotary shaft 32 rotates by a predetermined angle. A second communication hole 41 is formed.
[0021]
Here, the minimum gas flow rate at which the flame of the gas burner does not disappear varies depending on the type of fuel gas used and the ability of the gas burner. For this reason, it is good to be able to set the minimum gas flow rate for every different gas appliances, such as the kind of fuel gas to be used.
[0022]
In the present embodiment, a bypass passage 13 that connects the first hole 51 of the first communication hole and the gas passage 11 is provided in the apparatus main body 12, and an orifice 14 that sets a minimum gas flow rate is inserted in the bypass passage 13. . For this reason, the minimum gas flow rate corresponding to the kind of fuel gas and the capability of the gas burner can be set by exchanging the orifice 14.
[0023]
If the second communication hole 41 does not coincide with any of the first communication holes 51, 52, 53, 54, the internal passage 21 is closed and the supply of fuel gas to the gas passage 11 is stopped (see FIG. 2 (a)).
[0024]
On the other hand, the opening degree is changed by driving the motor 3 to rotate the rotating disk 4 and making the second communication hole 41 coincide with one of the first communication holes 51, 52, 53, 53, 54. The gas flow to the gas burner is adjusted. In consideration of safety and the like, an electromagnetic safety valve 6 that is an on-off valve is provided upstream of the gas inlet 23 (see FIG. 1).
[0025]
The gas passage 11 is provided with a pressure sensor 7 that detects a secondary pressure in the gas passage 11 between the gas injection nozzle and the gas valve 2. The pressure sensor 7 has an introduction cylinder 72 inserted through a sealing material 71 into a branch passage 11 a provided in a vertical direction from the gas passage 11, and a sealed empty chamber 73 communicating with the inside of the introduction cylinder 72. A resin thin plate (not shown) is incorporated therein.
[0026]
When the fuel gas flows through the gas passage 11, the thin plate is deformed by the secondary pressure of the fuel gas introduced into the empty chamber 73 through the introduction tube 72, and the amount of strain of the thin plate 11 at that time is attached to the thin plate. The secondary pressure is detected by detecting with a strain gauge.
[0027]
Here, in the gas stove whose operation is electronically controlled to enhance the convenience of the cook, the heating power of the gas burner is adjusted by, for example, a light touch switch (not shown) provided on the operation panel, For example, the gas flow rate is controlled so that the thermal power of the gas burner can be set in four stages from thermal power 1 to thermal power 4.
[0028]
In this case, although the thermal power is in the same stage, it is inconvenient if the actual thermal power of the gas burner does not match. For this reason, first, in the initial state, the secondary pressures respectively corresponding to the thermal power 1, thermal power 2, thermal power 3 and thermal power 4 are measured and stored as follows. That is, as shown in FIG. 2B, the motor 3 is rotated so that the second communication hole 41 coincides with the first hole 51 of the first communication hole, and the secondary pressure at that time is detected by the pressure sensor 7. Next, the second communication hole 41 is made to coincide with the third hole 53 and the fourth hole 54 (see FIG. 2E) of the first communication hole, and the secondary pressure at that time is detected by the pressure sensor 7.
[0029]
Next, these secondary pressures are divided into three equal parts to calculate secondary pressures corresponding to the thermal powers 2 and 3, and the target secondary pressures of the respective thermal powers from the thermal power 1 to the thermal power 4 are set as initial values. It is stored in a microcomputer that controls the operation of the gas stove. In this case, the rotation angle detection means 31 detects and stores the rotation angle of the motor 3 at that time, and also stores the number of steps of the motor 3.
[0030]
When the light touch switch is pressed to change the heating power of the gas burner, that is, the opening of the throttle portion to change the gas flow rate to the gas injection nozzle, the secondary pressure is detected by the pressure sensor 7 and the detected secondary pressure is detected. The motor 3 is feedback-controlled so that the pressure matches the target secondary pressure, and the opening degree of the gas passage 11 is controlled.
[0031]
By the way, when the motor 3 is feedback-controlled so as to match the set secondary pressure detected by the pressure sensor 7, the motor 3 may be rotated forward and backward repeatedly due to a difference in response speed between the motor 3 and the pressure sensor 7, etc. It takes time to control until they match. In this case, if the rotation speed of the motor 3 is slowed down, the rate of change in the heating power of the gas burner is slowed down, resulting in poor usability.
[0032]
In the present embodiment, the motor 3 is driven to rotate the rotating disk 4 in order to change the heating power of the gas burner, and the second communication hole 41 is replaced with one of the first communication holes 51, 52, 53, 53, 54. When the opening degree is changed so as to coincide with the opening number of the motor 3, the predetermined number of steps until reaching the stored number of steps of the motor 3 corresponding to the opening degree of the throttle unit corresponding to the heating power of the selected gas burner is switched to the switching position. And the motor 3 is feedforward controlled up to the number of steps.
[0033]
When the motor 3 exceeds the number of steps, the secondary pressure is detected by the pressure sensor 7, and feedback for controlling the motor 3 so that the detected secondary pressure matches the target secondary pressure stored as the initial value. Switch to control.
[0034]
In this case, the rotation speed of the motor 3 (the opening changing speed of the throttle unit) is feedback-controlled beyond the number of steps up to the number of steps that matches the switching position so that the gas flow rate can be changed rapidly. In this case, the rotational speed of the motor 3 was faster. In this case, the rotation speed of the motor 3 is set in a range in which the gas burner does not misfire, particularly when the gas burner's thermal power is reduced, but it differs between the case where the gas burner's thermal power is increased and the case where the thermal power is decreased. You may let them.
[0035]
As a result, when the cook's heating power change instruction is received by operating the touch panel, the gas flow rate to the gas burner is increased or decreased immediately, and the responsiveness to the cook's heating power change instruction is good, for example, quickly before boiling occurs Even when it is necessary to squeeze the thermal power of the gas burner, the occurrence of spilling can be prevented.
[0036]
In the case of feedback control, the rotational speed of the motor 3 is set in consideration of the difference in response speed between the motor 3 and the pressure sensor 7, and the secondary pressure detected by the pressure sensor 7 and the target secondary pressure are determined. Made it easier to match.
[0037]
As a result, the heating power change of the gas burner is started immediately in response to the cook's heating power change instruction, and time is not required for the control to make each heating power of the gas burner substantially constant. Compared to feedback control, the gas burner's heating power can be changed in a short time, making the gas appliance easier to use.
[0038]
In this embodiment, the motor 3 is a stepping motor, and the switching position is set by the number of steps corresponding to the rotation angle of the motor. However, the present invention is not limited to this. For example, an encoder is installed in a geared motor. The rotation angle may be detected by mounting, and the switching position may be set based on the detected angle.
[0039]
Further, when the gas burner is ignited, the motor 3 may be controlled as described above when the motor 3 is driven to set the opening of the gas passage so as to obtain a predetermined heating power.
[0040]
【The invention's effect】
As described above, in the gas flow rate control device according to the present invention, the heating power of the gas burner is quickly changed in response to the cook's heating power change instruction, and the driving means is not repeatedly forward / reversely rotated. In addition, since the heating power is changed in a short time, there is an effect that the gas appliance is easy to use.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a gas flow rate control device according to the present invention. FIGS. 2A to 2E are diagrams illustrating flow rate adjustment by a gas valve.
DESCRIPTION OF SYMBOLS 1 Gas flow control apparatus 2 Gas valve 3 Motor 32 Rotation angle detection means 4 Rotating disk 5 Fixed disk 7 Pressure sensor

Claims (3)

A gas passage having a gas injection nozzle at the tip and supplying fuel gas to the gas burner is provided with a throttle portion that changes the opening of the gas passage and adjusts the gas flow rate to the gas burner, and the gas burner and the throttle portion. In a gas flow rate control device comprising a secondary pressure detecting means for detecting a secondary pressure of the fuel gas in the gas passage between,
When a plurality of target openings of the gas passage are set in advance and the throttle is driven to change the opening of the gas passage from the current opening to the selected target opening, the time until the target opening is reached. When a switching position is set at a predetermined position and the opening reaches the switching position, a preset secondary pressure set in advance corresponding to the target opening and a secondary pressure detected by the secondary pressure detecting means are obtained. A gas flow rate control device that switches to feedback control that controls the opening so as to match. 2. The gas flow rate control device according to claim 1, wherein the opening degree changing speed of the throttle portion is made faster than the opening degree changing speed of the throttle portion from the switching position to the target opening degree until reaching the switching position. 3. The gas flow rate control device according to claim 1, wherein the throttle unit includes a motor that can be rotated to a predetermined rotation angle and stopped, and a target opening degree and a switching position are set according to the rotation angle.

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