JPS6239330B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gas combustion control device that proportionally controls the amount of gas supplied to a burner in accordance with the amount of current applied.

Structure of a conventional example and its problems A conventional gas combustion control device of this type is shown in FIG. In FIG. 1, reference numeral 1 designates an original solenoid valve, and 2 represents an original solenoid valve, from which a pilot passage 3 is branched downstream, and when the original solenoid valve 2 is opened, a pilot burner 4 is ignited. 5 is a shutoff valve, and a proportional control valve 6 is provided downstream thereof. The proportional control valve 6 includes a well-known governor section A consisting of a valve seat 7, a valve body 8, a diaphragm 9 that operates together with the valve body 8, and a closing elastic body 10 that biases the valve in the valve closing direction, and a coil 11. and an electromagnetic drive section B consisting of a yoke 12 and a plunger 14 whose both ends are non-slidingly supported on the axis of the coil 11 by leaf springs 13. control.

15 is a burner, 16 is a heat exchanger, and 17 is a heat-sensitive element that is installed downstream of the heat exchanger 16 and detects the water temperature.The signal is compared with a set value in the controller 18, and the deviation signal is Therefore, the amount of current applied to the proportional control valve 6 is determined. 19 is a faucet, and 20 is a shower head. In other words, the temperature of the hot water is detected, and the amount of combustion is controlled according to the signal to obtain hot water at the desired temperature.

The proportional control valve 6 used in this type of gas combustion control device needs to accurately control the gas flow rate over a wide range from the minimum combustion amount to the maximum combustion amount determined from the burner side, and also controls the gas flow rate to the burner 15. A closing function that completely shuts off is required. The former case is particularly important in air-fuel ratio control, and the latter case, even if the amount of electricity supplied to the proportional control valve 6 is reduced to zero, gas leaks and the amount of combustion becomes less than the minimum combustion amount, causing problems such as backup fire. It's for a reason. In order to solve the former problem, it is necessary to make sure that the electromagnetic force generated by the electromagnetic drive unit B acts faithfully on the valve body 8 without being subjected to disturbances such as sliding friction. The contact area between the seat 7 and the valve body 8 is
It is necessary to select a shape and material that will not lock. The lock here refers to the valve seat 7 and the valve body 8.
This refers to a state in which the valve body 8 is stuck to the valve seat 7 side under the force of the closing elastic body 10 and cannot be opened smoothly. On the other hand, in order to solve the latter problem, a common method is to provide an elastic member at the contact portion between the valve body 8 and the valve seat 7, and to increase the closing force of the closing elastic body 10. However, in this case, since the valve body 8 is held on the valve seat 7 via the elastic member, adhesion is likely to occur, and the valve body 8 is held on the valve seat 7.
The valve will not open even if the coil 11 is energized, resulting in poor control characteristics, especially in a small flow rate range. Second
The figure shows this situation. Even if a predetermined coil current I ₁ (for example, a slow ignition current) is applied, the predetermined gas flow rate Q ₁ is not obtained, and the lock is released due to an unspecified amount of energization I The valve suddenly opens at _X , and for example, an explosive ignition occurs.

Also, if the device is not used for a long period of time,
The adhesive strength may become even greater and may become inoperable.

In other words, since it is not possible to solve the former problem and the latter problem at the same time, conventionally it has been necessary to provide a dedicated shutoff valve 5 upstream of the proportional control valve 6, which reduces the cost of the gas combustion control device. This has become a factor in the increase in space.

In addition to the above example, FIG. 3 shows an example of a proportional control valve with a closing function. 35 is a fluid inlet, 21 is a fluid outlet, 22 is a first valve seat, 23 is a first valve seat 22
The first valve body is provided opposite to the first valve body. The first valve seat 22 and the first valve body 23 change the cross-sectional area of the fluid flow path and control the pressure. 24 is the first seat, which is provided upstream of the second valve seat 22. 2
Reference numeral 5 denotes a second valve body that faces the second valve seat 24 and is provided integrally with the first valve body 23, and an elastic body 26 is provided on the side of the contact surface with the second valve seat 24. ing. The second valve seat 24 and the second valve body 25 configured as described above
Although the fluid flow path can be closed, the primary gas pressure acts to push the second valve body 25 open, and the second valve body 2
Since this has the same effect as reducing the closing force of the spring 27 that biases the valve 5 in the closing direction, there is a problem that the actual valve closing pressure changes depending on the magnitude of the primary pressure.

Purpose of the Invention The present invention solves these conventional problems, and satisfies both the control performance and closing function of a proportional control valve, thereby eliminating the need for a closing valve, thereby reducing the cost of a gas combustion control device. The purpose is to realize miniaturization and compactness.

Structure of the Invention In order to achieve this object, the present invention has a first valve body that controls fluid pressure and a second valve body that closes a fluid passage in an inlet side primary pressure chamber, and has an effective pressure receiving area of a second valve body. Insert the same diaphragm as the valve body into the second pressure chamber.
The first valve body and the second valve body are fixedly provided in conjunction with the valve body, and the first valve body and the second valve body are simultaneously driven.
A proportional control valve having an electric drive unit that generates a force to move a first valve member in the valve opening direction and a gas burner are provided, and the proportional control valve is energized by the gas burner. An ignition operation circuit that applies an instantaneous maximum allowable current at the start of combustion, and immediately thereafter, a certain constant current within a proportional control region that continuously obtains a maximum combustion gas flow rate from a minimum combustion gas flow rate; A controller is provided that includes a proportional control circuit that conducts current within a proportional control region.

With this configuration, the second valve body closes the fluid passage, and when the gas burner starts combustion, the ignition operation circuit operates to supply instantaneous maximum allowable current and immediately supply appropriate slow ignition current within the proportional control region. , second
When the valve body is closed, it works to ensure that the valve opens even if it is sticky or the like, and gentle ignition is also performed quietly. Furthermore, after ignition, it acts to ensure control within the proportional control region.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. In FIG. 4, a proportional control valve 40 and a pilot passage 3 are branched downstream of the main stock 1 and the main solenoid valve 2, and a pilot burner 4 is provided at the tip of the pilot passage 3. The proportional control valve 40 includes an electric valve body 41 that controls fluid pressure;
A first valve seat 42 and a second valve body 4 that closes the fluid passage.
3. A second valve seat 44 is formed to face each other. In particular, the second valve body 43 is made of an elastic material such as rubber, and has a brass back plate 45 on the back side. These first
The plunger 46 connected to the valve body 41 and the second valve body 43 is supported by two leaf springs 55 so as to be vertically movable without sliding. The electromagnetic coil 47 outside the plunger 46, the yoke 48, and the like constitute an electromagnetic drive section. The gas pressure in the primary pressure chamber 49 is controlled by a diaphragm 51 fixed to the upper end of the plunger 46.
The spring 52 biases the second valve body 43 in the direction of closing it. 50 is an O-ring. An outlet 52 of the proportional control valve 40 is connected to a burner 53 . The electromagnetic coil 47 is electrically connected to a controller 54 including a proportional control region limiting circuit and an ignition operation circuit.

The operation of this embodiment in the above configuration will be explained using FIG. 5. When starting combustion in the burner 53 with the main solenoid valve 1 and the main solenoid valve 2 open,
When the main solenoid valve 2 is opened, the pilot burner 4 is ignited first, and then the ignition operation circuit of the controller 54 is activated, and the maximum allowable current I ₅ is suddenly applied to the solenoid coil 47 for a moment. . The electromagnetic force generated by the maximum allowable current I ₅ is much larger than the force of the spring 52 and leaf spring 55 that urges the second valve body 43 in the closing direction, and the second valve body 43 is
To surely open a second valve body 43 even if it is stuck to a valve seat 44. Immediately thereafter, the ignition operating circuit acts to immediately switch the proportional valve current to the slow ignition current _I3 . Therefore, the burner 53 is quietly and slowly ignited at the gas flow rate Q _n . slow ignition current
I ₃ is the proportional valve current I ₂ to obtain the maximum rated combustion gas amount Q _nax
Depending on the ignition characteristics of the burner, any current can be selected as long as it is within a so-called proportional control region between the proportional valve current I ₄ and the proportional valve current I 4 for obtaining the minimum rated combustion gas amount _Q nio. After ignition, by the action of the proportional control circuit including the proportional control region limiting circuit, proportional control can be performed to increase or decrease the amount of burner combustion gas as necessary within the proportional control region, and the upper limit current value of the proportional control region I ₄ When trying to further reduce the amount of combustion gas after the proportional valve current reaches , the proportional valve current immediately becomes zero, and conversely, the lower limit current value I ₂
When attempting to further increase the amount of combustion gas after reaching , the proportional valve current acts to maintain the lower limit current value _I2 . Therefore, there is no possibility of causing a backfire phenomenon in the burner by throttling the gas to the minimum rated combustion gas amount, or of damaging the equipment by exceeding the maximum rated combustion gas amount. In addition, when the second valve body 43 of the proportional control valve 40 closes the second valve seat 44, the gas pressure in the primary pressure chamber 49 is
and diaphragm 51 in opposite directions,
Since the second valve body 43 and the diaphragm 51 have the same effective pressure receiving area, they cancel each other out, and the valve closing force is not affected by the magnitude of the primary pressure but is maintained at a constant value due to the force of the spring 52 or the leaf spring 55. can be obtained.

The effective pressure receiving area S _V of the first valve body 41 is also the same as the effective pressure receiving area S _D of the diaphragm 51, and the electromagnetic force, the primary pressure is P ₁ , the secondary pressure is P ₂ , and the second valve body 4
Spring 52 and leaf spring 5 that act in the direction of closing 3
Letting the force of 5 be F, the force balance equation is F + P ₁・S _V = P ₁・S _D +P ₂・S _V + Here, S _V = S _D , so P ₂・S _V = F− Therefore, P ₂ =F-/ _SV .

increases in proportion to the square of the proportional valve current I, and the gas flow rate _Qq is proportional to the square root of the secondary pressure _P2 , so it can be seen that the gas flow rate _Qq and the proportional valve current I are inversely proportional. .

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

(1) It has a first valve body that controls fluid pressure and a second valve body that closes a fluid passage in the primary pressure chamber on the inlet side, and a diaphragm with the same effective pressure receiving area as the second valve body is connected to the primary pressure chamber. The second valve body is fixed in conjunction with the second valve body to simultaneously drive both valve bodies, and as the amount of current increases, the second valve body
a proportional control valve having an electric drive unit that generates a force for operating a valve body in a valve opening direction and a first valve body in a valve closing direction; a controller provided with a gas burner and comprising an ignition operation circuit and a proportional control circuit; When the gas burner starts combustion,
The instantaneous maximum allowable current is applied, and the proportional valve current immediately switches to the proportional control area, and then operates within the proportional control area, allowing combustion to start reliably and quietly even if the valve sticks, and close the valve. This has the effect of providing a gas proportional combustion control device that can reliably achieve the same effect.

(2) Since the proportional control valve has a function that satisfies both the closing function and the proportional control function, a low-cost, compact gas combustion control device can be created.

(3) Since the configuration is such that the primary pressures cancel each other out, a constant and stable valve closing pressure can be ensured without being affected by fluctuations in the primary gas pressure, resulting in excellent closing performance.

(4) The proportional control area limited circuit ensures maximum and minimum rated combustion gas quantities, and prevents backfire or over-combustion caused by restricting the combustion gas quantity too much.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional gas combustion control device, Fig. 2 is a control characteristic diagram of a proportional control valve, Fig. 3 is a sectional view of a conventional proportional control valve, and Fig. 4 is a gas combustion control device of the present invention. FIG. 5 is a block diagram showing one embodiment of the control device, and is a control characteristic diagram of the proportional control valve. 40... Proportional control valve, 41... First valve body, 43
...Second valve body, 49...Primary pressure chamber, 51...Diaphragm, 53...Gas burner, 54...Controller.

Claims (1)

[Claims] 1. A first valve body that controls fluid pressure and a second valve body that closes a fluid passage in a primary pressure chamber on the inlet side, and a diaphragm that has the same effective pressure receiving area as the second valve body as a primary pressure chamber. The first valve body and the second valve body are provided in a pressure chamber in a fixed manner in conjunction with the second valve body, and the first valve body and the second valve body are driven simultaneously, and the first valve body is moved in the valve opening direction as the amount of energization increases. A proportional control valve having an electric drive unit that generates a force to operate the valve in the valve closing direction, and a gas burner are provided,
The proportional control valve is energized by applying an instantaneous maximum allowable current at the start of combustion in the gas burner, and immediately after that, applying a certain current within a proportional control region to continuously obtain a maximum combustion gas flow rate from a minimum combustion gas flow rate. A gas combustion control device comprising a controller comprising an ignition operation circuit that conducts current, and a proportional control circuit that conducts current within the proportional control region after the ignition. 2. When the proportional control circuit of the controller attempts to further reduce the amount of combustion gas after reaching the upper limit current value of the proportional control region, the proportional valve current is set to zero, and after reaching the lower limit current value, the amount of combustion gas is further reduced. 2. The gas combustion control device according to claim 1, further comprising a proportional control region limiting circuit that maintains the proportional valve current at a lower limit current value when increasing the proportional valve current.