JP3819307B2 - 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 appliance such as a gas stove.
[0002]
[Prior art]
This type of gas flow rate control device is known, for example, from Japanese Patent Laid-Open No. 2001-56118, and is used, for example, to reduce the change in the setting power of the gas burner when adjusting the heating power of the gas burner provided in the gas stove. Is done.
[0003]
In this case, the gas flow rate control device is a motor-driven type which is a flow rate adjusting means provided with a throttle part for changing the opening degree of the gas passage in the gas passage connected to the gas injection nozzle connected to the mixing pipe of the gas burner. A gas valve, and a pressure sensor which is a secondary pressure detecting means for detecting a secondary pressure in a gas passage provided between the gas valve and the gas injection nozzle.
[0004]
Then, the microcomputer that controls the operation of the gas stove controls the motor so that the secondary pressure detected by the pressure sensor matches the target secondary pressure stored in advance in the microcomputer, and adjusts the opening of the throttle section. Reduce changes in set firepower.
[0005]
[Problems to be solved by the invention]
However, in the above case, when the secondary pressure when the opening of the gas valve is maximum due to fluctuation and lowering of the primary pressure in the gas passage, the secondary pressure and the target secondary pressure The heating power of the gas burner cannot be changed even if the opening is changed beyond the opening of the gas valve that matches. For this reason, there has been a problem that the heating power width between the set heating powers becomes non-uniform, and the usability of the gas appliance becomes worse.
[0006]
Moreover, in the above, every time the motor is controlled by controlling the motor, the CPU of the microcomputer calculates the control position of the motor from the detection result of the pressure sensor, and the motor drive control for adjusting the opening of the gas valve Since processing is performed simultaneously, the load on the CPU increases. For this reason, in particular, a gas stove that electronically controls the operation of the utensil in order to enhance the convenience of the cooker requires a CPU with a high arithmetic processing capability, resulting in a high cost.
[0007]
Therefore, in view of the above problems, the present invention does not require a CPU having a high processing capacity, and in addition, even when the primary pressure changes, the gas flow rate control capable of equalizing the thermal power width between the set thermal powers of the gas burner. It is an object to provide an apparatus.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, a flow rate adjusting means for adjusting the gas flow rate of the fuel gas to the gas injection nozzle and a secondary pressure of the fuel gas downstream of the flow rate adjusting means are provided in the gas passage connected to the gas injection nozzle. A secondary pressure detecting means for detecting the secondary pressure, and the flow rate adjusting means changes the opening of the gas passage to determine the set thermal power of the gas burner, and the secondary pressure corresponding to the gas flow rate from the minimum gas flow rate to the maximum gas flow rate. in the gas flow control device having a throttle portion for increasing or decreasing a flow of fuel gas to the gas passage through the flow rate control means, wherein the detecting the secondary pressure by a secondary pressure detecting means, the secondary pressure the detected each The opening of the throttle is corrected so that the secondary pressure corresponds to the gas flow rate that determines the set thermal power, and the heating power of the gas burner is adjusted with the corrected opening of the throttle , and the secondary pressure Detection of the throttle opening In addition, the minimum opening with the minimum gas flow and the maximum opening with the maximum gas flow are performed respectively, and the secondary pressure and opening in the intermediate thermal power are calculated from the secondary pressure measured at both openings. When the secondary pressure detected at the maximum opening is higher than the preset initial secondary pressure, the secondary pressure and opening at the intermediate thermal power are calculated using the initial secondary pressure instead of the detected secondary pressure. characterized in that it.
[0009]
According to the present invention, when the fuel gas is caused to flow through the gas passage, the fuel gas whose flow rate is adjusted by the flow rate adjusting means flows to the gas injection nozzle. In this case, the secondary pressure detecting means detects the secondary pressure of the fuel gas in the gas passage between the flow rate adjusting means and the gas injection nozzle, and determines each set thermal power of the gas burner from the detected secondary pressure. The throttle opening corresponding to the gas flow rate is corrected. And the thermal power of each gas burner is adjusted according to the opening degree of the throttle part after correction.
[0010]
In this case, the detection of the secondary pressure, for example, it is preferable to perform the maximum opening there in minimum opening and maximum gas flow rate is minimal gas flow rate by changing the opening degree of the throttle portion.
[0011]
In addition, when detecting and correcting the secondary pressure at the maximum opening of the throttle part, if the correction is based on the secondary pressure that is increased due to the fluctuation of the primary pressure, the gas burner is more than necessary. It is thought that firepower becomes high.
[0012]
In this case, the detection of the secondary pressure is performed for maximum opening there at a maximum gas flow rate by changing the opening degree of the throttle portion, the detected secondary pressure is higher than the preset initial secondary pressure, detected What is necessary is just to correct | amend the opening degree of a throttle | throttle part from this initial secondary pressure instead of the made secondary pressure.
[0013]
Further, when the opening of the throttle portion is corrected based on the secondary pressure detected by the secondary pressure detecting means, the characteristics of the secondary pressure detecting means change with time, for example, the secondary pressure is displayed higher than usual. If it becomes like this, inconveniences such as an unnecessarily high heating power of the gas burner occur.
[0014]
In this case, if the detected secondary pressure is out of a predetermined pressure range, a warning of the failure of the secondary pressure detection means may be issued.
[0015]
It is preferable that the flow rate adjusting means has a closing function.
[0016]
In this case, an on-off valve is provided between the secondary pressure detecting means and the gas injection nozzle, and when the supply of the fuel gas to the gas injection nozzle is stopped, the on-off valve is closed before the flow rate adjusting means, By detecting the pressure drop rate by the detecting means, it is possible to determine the occurrence of gas leakage from the secondary pressure detecting means or the like.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2, reference numeral 1 denotes a gas flow rate control device of the present invention. The gas flow rate control device 1 includes, for example, a device main body 12 including 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 is a flow rate adjusting means for adjusting the gas 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.
[0018]
The gas valve 2 has a valve casing 22 having an internal passage 21, and a gas inlet 23 is opened on a side surface of the valve casing 22, and the gas inlet 23 communicates with the gas passage 11 through the internal passage 21. 22 communicates with the gas outlet 24 on the top surface.
[0019]
A motor 3 such as a stepping motor or a geared motor having rotation 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.
[0020]
The internal passage 21 is positioned upstream of the gas outlet 23 and is connected to one end of a 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 constitute a throttle portion that changes the opening degree of the passage area of the internal passage 21.
[0021]
As shown in FIG. 2, the fixed disk 5 has five holes 51, 52, 53, 54, and 55 that are the first communication holes continuously on the same circumference with different opening areas. Is provided. On the other hand, when the rotary shaft 32 is rotated by a predetermined angle, the rotary disc 4 coincides with the holes 51, 52, 53, 54, 55 of the first communication hole and flows out of the gas inlet 23 and the gas through the internal passage 21. One oval second communication hole 41 that allows communication with the portion 24 is provided.
[0022]
Here, the minimum gas flow rate at which the flame of the gas burner does not disappear differs depending on the type of fuel gas used. For this reason, it is necessary to be able to set the minimum gas flow rate for each gas appliance having different types of fuel gas to be used.
[0023]
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. .
[0024]
If the second communication hole 41 does not coincide with any of the first communication holes 51, 52, 53, 54, 55, the internal passage 21 is closed and the supply of fuel gas to the gas passage 11 is stopped. (See FIG. 2 (a)). 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, 55. Thus, the gas flow rate is adjusted.
[0025]
Here, in the gas stove whose operation is electronically controlled in order to enhance the convenience of the cooker, the heating power of the gas burner is adjusted by, for example, a light touch switch provided on the operation panel on the front of the stove. In this case, the gas valve 2 is controlled so that, for example, the heating power of the gas burner can be set in five stages from the heating power 1 to the heating power 5.
[0026]
In the present embodiment, when the light touch switch is pressed and the heating power is 1, the motor 3 is driven to rotate the rotating shaft 32 in one direction so that the second communication hole 41 coincides with the first hole 51 of the first communication hole. In this case, the minimum gas flow rate is such that the flame of the gas burner does not disappear (see FIG. 2B).
[0027]
Next, when the touch switch is pressed to set the heating power 2, the motor 3 is driven to rotate the rotating shaft 32 in one direction, and the second communication hole 41 is changed to the first hole 51 and the second hole 52 of the first communication hole. Match. In this case, the flow rate of the fuel gas to the gas passage 11 can be changed according to the area where the first hole 51 and the second hole 52 of the first communication hole coincide with the second communication hole 41 (FIG. 2C). reference).
[0028]
Then, with the thermal power 3, the second communication hole 41 is changed to the second hole 52 and the third hole 53 of the first communication hole (see FIG. 2D), and with the thermal power 4, the second communication hole 41 is changed to the first communication hole. In the third hole 53 and the fourth hole 54 (see FIG. 2E), in the case of the thermal power 5, the second communication hole 41 is replaced with the fourth hole 54 and the fifth hole 55 of the first communication hole (see FIG. 2F). ) To match. Also in this case, the gas flow rate can be adjusted by changing the area of each of the holes 51 to 55 of the first communication hole where the second communication holes 41 coincide.
[0029]
Here, in the initial state, the opening degree (set thermal power) of the gas valve 2 is adjusted as follows. That is, the pressure sensor 6 described later determines the pressure of the fuel gas in the gas passage 11 at the minimum gas flow rate (thermal power 1) (hereinafter referred to as “secondary pressure”) and the secondary pressure at the maximum gas flow rate (thermal power 5). Detect each.
[0030]
These secondary pressures are divided into four equal parts to calculate secondary pressures corresponding to thermal power 2, thermal power 3 and thermal power 4, and the motor 3 is driven so that the detected value of the pressure sensor 6 becomes the secondary pressure. Thus, the opening degree (gas flow rate) of the gas valve 2 is adjusted by rotating the rotating disk 4.
[0031]
In this case, the rotation angle of the adjusted rotating shaft 32 of the motor 3 is detected by the rotation angle detecting means 31, and the microcomputer that controls the operation of the gas stove with the rotation angle and the secondary pressure at each heating power at that time as initial values. I remember it.
[0032]
In order to reliably ignite the gas burner, it is preferable to perform the ignition operation by rotating the rotating shaft 32 by the motor 3 to the position of the thermal power 5 at which the gas flow rate becomes maximum.
[0033]
The gas passage 11 is provided with a pressure sensor 6 that detects a secondary pressure in the gas passage 11. The pressure sensor 6 has a rod 62 inserted through a seal material 61 into a branch passage 11 a provided in a vertical direction from the gas passage 11, and a resin thin plate (not shown) is connected to one end of the rod 62. Has been. When the fuel gas flows through the gas passage 11, the rod 11 is pushed upward by the secondary pressure, and the secondary pressure is detected by detecting the amount of strain of the thin plate 11 at that time with a strain gauge attached to the thin plate. .
[0034]
By the way, in the gas flow rate control device 1, the set thermal power changes when the original pressure (hereinafter referred to as “primary pressure”) of the fuel gas on the upstream side of the gas valve 2 fluctuates. In this case, the set thermal power is adjusted by adjusting the rotation angle of the rotary shaft 32 via the motor 3 by feedback control from the secondary pressure detected by the pressure sensor 6 so as to match the initial secondary pressure stored in the microcomputer. However, this causes the following problems.
[0035]
That is, referring to FIG. 3, when the primary pressure in the gas passage 11 fluctuates and becomes low and the secondary pressure in the gas passage 11 becomes low (solid line), the secondary pressure and the initial secondary pressure (dotted line). There is a problem in that the heating power of the gas burner does not change even if the area where the second communication hole 41 and the first communication hole match is increased from the point B where the
[0036]
In the present embodiment, when the fuel gas flows through the gas passage 11 via the gas valve 2, the secondary pressure is detected by the pressure sensor 6, and the opening of the throttle portion of the gas valve 2 is adjusted according to the secondary pressure. I decided to correct it.
[0037]
With reference to FIG. 4, correction of the opening of the throttle portion of the gas valve 2 will be described. The motor 3 is driven to the position where the maximum gas flow rate (thermal power 5) shown in FIG. At this time, the secondary pressure in the gas passage 11 is detected by the pressure sensor 6.
[0038]
For example, when the secondary pressure detected by the pressure sensor 6 becomes lower than the initial secondary pressure due to a decrease in the primary pressure (dotted line 1), the motor 3 is moved to a position where the minimum gas flow rate (thermal power 1) shown in FIG. The rotary disk 4 is driven to rotate, and the secondary pressure at that time is detected.
[0039]
The detected secondary pressure at the maximum gas flow rate and the minimum gas flow rate is stored in the microcomputer, and the differential pressure between these secondary pressures is equally divided into four by the microcomputer to correspond to the thermal power 2, thermal power 3, and thermal power 4. The pressure is calculated, and each secondary pressure and the rotation angle of the rotating shaft 32 at that time are calculated and stored, thereby correcting the opening degree.
[0040]
As a result, even if the secondary pressure becomes lower than the initial secondary pressure due to a decrease in the primary pressure, the thermal power of each stage is corrected from the secondary pressure between the maximum gas flow rate and the minimum gas flow rate. The firepower width is even.
[0041]
On the other hand, for example, when the secondary pressure detected by the pressure sensor 6 becomes higher than the initial secondary pressure due to an increase in the primary pressure (dotted line 2), the correction based on this secondary pressure is particularly The firepower of may increase more than necessary.
[0042]
In this case, the motor 3 is driven to the position where the minimum gas flow rate (thermal power 1) shown in FIG. 2B is reached to rotate the rotating disk 4, and the secondary pressure at that time is detected.
[0043]
The detected secondary pressure at the minimum gas flow rate and the initial secondary pressure at the maximum gas flow rate are stored in a microcomputer, and the differential pressure between these secondary pressures is equally divided into four by the microcomputer, the thermal power 2, the thermal power 3, and the thermal power The secondary pressure corresponding to 4 is obtained, and each secondary pressure and the rotation angle of the rotating shaft 32 at that time are calculated and stored, thereby correcting the opening degree. Thus, no larger than necessary thermal gas burner not using the region A shown in FIG.
[0044]
Further, in the gas flow rate control device 1 of the present embodiment, since the rotation angle of the rotating shaft 32 of the motor 3 is only controlled based on the corrected data at the time of adjusting the heating power, the pressure sensor 6 is adjusted every time the heating power is adjusted. Compared with the case where the process of calculating the rotation angle of the rotating shaft 32 of the motor 3 from the detected value and the drive control process of the motor 3 are performed simultaneously, no load is applied to the CPU.
[0045]
If the secondary pressure detected by the pressure sensor 6 is out of a predetermined pressure range during the ignition operation of the gas burner, the microcomputer may determine that the pressure sensor 6 has failed and warn about it. .
[0046]
In addition, as shown in FIG. 1, an electromagnetic on-off valve 7 may be provided in the gas passage 11 on the downstream side of the pressure sensor 6. In this case, when the gas burner is extinguished, the electromagnetic on-off valve 7 is closed, then the gas valve 2 is closed to seal the gas passage, and the pressure drop rate by the pressure sensor 6 at that time is detected. For example, it may be possible to determine the occurrence of gas leakage from the pressure sensor 6 or the like.
[0047]
In this embodiment, the electromagnetic safety valve 7 is provided in the gas passage 11 on the downstream side of the pressure sensor 6. However, the present invention is not limited to this. For example, as shown in FIG. A safety valve 8 may be provided.
[0048]
In the present embodiment, the electromagnetic safety valve 7 is provided in the gas passage 11 on the downstream side of the pressure sensor 6 and the gas valve 2 is provided on the upstream side of the pressure sensor 6. However, the present invention is not limited to this. As shown in FIG. 6, an electromagnetic safety valve 7 may be provided upstream of the gas valve 2.
[0049]
Moreover, as shown in FIG. 6, you may provide the stopper 9 which restrict | limits rotation of a rotating shaft.
[0050]
【The invention's effect】
As described above, the gas flow rate control device of the present invention does not require a CPU with high calculation processing capacity, and furthermore, even when the primary pressure changes, the thermal power width between the set thermal powers of the gas burner can be made uniform. There is an effect.
[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 2F are diagrams illustrating flow rate adjustment by a gas valve. FIG. 3 is a flow rate of gas when a primary pressure fluctuates. FIG. 4 is a graph illustrating adjustment of the set thermal power by the gas flow control device of the present invention. FIG. 5 is a cross-sectional view illustrating a gas flow control device according to another embodiment. FIG. 7 is a cross-sectional view illustrating a gas flow control device according to another embodiment. FIG. 7 is a cross-sectional view illustrating a gas flow control device according to another embodiment.
1 Gas flow control device 11 Gas passage 2 Gas valve 4 Rotating disk 5 Fixed disk 6 Pressure sensor

Claims (4)

A flow rate adjusting means for adjusting the gas flow rate of the fuel gas to the gas injection nozzle, and a secondary pressure detecting means for detecting the secondary pressure of the fuel gas downstream of the flow rate adjusting means in the gas passage connected to the gas injection nozzle The flow rate adjusting means has a throttle part that increases or decreases the secondary pressure corresponding to the gas flow rate from the minimum gas flow rate to the maximum gas flow rate that determines the set thermal power of the gas burner by changing the opening of the gas passage In the gas flow rate control device, the fuel gas is caused to flow through the gas passage through the flow rate adjusting means, the secondary pressure is detected by the secondary pressure detecting means, and the detected secondary pressure becomes a gas flow rate that determines each set thermal power. The opening of the restrictor is corrected so as to obtain a corresponding secondary pressure, and the heating power of the gas burner is adjusted with the corrected opening of the restrictor. Available with minimum gas flow by changing the opening The maximum opening that is the minimum opening and the maximum gas flow rate is performed respectively, and the secondary pressure and opening at the intermediate heating power are calculated from the secondary pressure measured at both openings, and the second opening detected at the maximum opening. Gas flow rate characterized in that when the secondary pressure becomes higher than a preset initial secondary pressure, the secondary pressure and opening degree in the intermediate thermal power are calculated using the initial secondary pressure instead of the detected secondary pressure. Control device. 2. The gas flow rate control device according to claim 1, wherein when the detected secondary pressure is out of a predetermined pressure range, a failure of the secondary pressure detecting means is warned. The gas flow rate control device according to claim 1 or 2 , wherein the flow rate adjusting means has a closing function. An on-off valve is provided between the secondary pressure detection means and the gas injection nozzle, and when the supply of fuel gas to the gas injection nozzle is stopped, the on-off valve is closed before the flow rate adjustment means, and the detection means 4. The gas flow rate control device according to claim 3, wherein the pressure drop rate is detected.