JPH01225812A - Gas combustion apparatus - Google Patents

Abstract

PURPOSE:To keep an air-fuel ratio at an excellent value, by a method wherein the opening of a proportional solenoid valve of a gas combustion device to forcibly feed combustion air with the aid of a motor fan is controlled by feedback of not only an applying current but also an air pressure on the outlet side of the motor fan. CONSTITUTION:A proportional solenoid valve 30 comprises a diaphragm 34, by which its interior is separated into a valve chamber 38 through which gas flows and a closed back pressure chamber 39, and an electromagnetic drive device 40 to move a moving valve body 33 against a spring 36 according to a current applied to a coil 46. The back pressure chamber 39 is communicated between a feed port 18 and a burner 10 through a communicating pipe 29. When a command from an electronic control device 60 is simultaneously inputted to the proportional solenoid valve 30 and a motor fan 19, the motor fan 19 responds in delay, and a pressure in an inner drum 17 is also changed in delay. However, since the pressure is introduced to the back pressure chamber 39 and the proportional solenoid valve 30 is delayed in a similar manner described above, an air-fuel ratio is kept approximately at an excellent value.

Description

[Detailed Description of the Invention] (Industrial Application Field) In order to make the device more compact, the present invention uses an electric fan to forcibly blow air in an amount proportional to the amount of gas supplied into the inner shell in which a gas burner is installed. This invention relates to gas combustion equipment using an electrical proportional control system.

(Prior art) This type of gas combustion equipment uses a proportional solenoid valve whose opening degree changes continuously according to the applied current to control the amount of gas supplied to the gas burner, and a proportional solenoid valve whose rotation speed changes according to the input power. It is equipped with an electric fan that continuously changes to control the amount of air supplied into the interior, and an electronic control device correlates the applied current and input power according to the amount of heat required for the gas burner depending on the operating state of the gas combustion equipment. is controlled so that the gas supply amount and air supply amount change proportionally.

(Problem to be Solved by the Invention) In such conventional technology, the opening of the proportional solenoid valve responds to the applied current with almost no time delay, but the rotating part of the electric fan has considerable inertia. Therefore, the rotation speed of the electric fan responds with a delay to the input power. That is,
As shown in FIG. 3, in response to a decrease in the required amount of heat starting at time t1 and ending at time t2, the opening degree of the proportional solenoid valve decreases as shown by the two-dot chain line C1a, and reaches a predetermined opening degree at time t2. Therefore, the amount of gas supplied decreases as shown by the two-dot chain line Bla and reaches the predetermined amount of supply at time t2, but the amount of air supplied by the electric fan decreases as shown by the solid line A1, and at time t3, which is later than time t2. Otherwise, the prescribed supply amount will not be achieved. The proportional gas supply amount corresponding to the decrease in the air supply amount shown by the solid line AI is as shown by the broken line Blc, so between time t1 and t3, the two-dot chain line Bla and the broken line BlcO
There is a temporary excess of air by the difference. The greater the rate of decrease in the required heat quantity, the greater the proportion of excess air, which may occasionally cause flame lift or extinguish the flame by blow-off. Such problems occur rapidly in instantaneous gas water heaters, and tend to occur when the amount of hot water dispensed or the output/lA temperature is reduced. Similarly, when the required heat amount is increased, the increase in the air supply amount is delayed relative to the increase in the gas supply amount, as shown in FIG. 3 (from time t4 to t
6, there is a temporary shortage of air by the difference between the two-dot chain line B2a and the broken line B2c, and in this case, there is little risk of flame lift or blow-off, but incomplete combustion temporarily occurs.

The present invention uses a proportional solenoid valve with a gas governor function, and controls the opening of the proportional solenoid valve according to the air supply amount by feeding back the wind pressure on the outlet side of the electric fan to the back pressure chamber of the proportional solenoid valve. The purpose is to maintain a proportional relationship between the amounts of gas and air supplied even in a transient state where the required amount of heat changes.

(Means for Achieving the Object) For this purpose, the gas combustion equipment according to the present invention has an inner shell 17 in which a gas burner 10 is installed, as illustrated in the attached drawings.
and an air supply port 18 opened in the inner shell 17 on the side opposite to the burner head 13.16 of the gas burner 10, the opening of which changes continuously according to the applied current, and the amount of gas supplied to the gas burner 10. an electric fan 19 that is connected to the air supply port 18 and whose rotation speed changes continuously according to input power to control the amount of air supplied into the inner shell 17; The proportional solenoid valve 30 is arranged so that the air supply amount changes proportionally in accordance with a change in the gas supply amount.
In the gas combustion equipment, the proportional solenoid valve 30 includes a valve casing 31 and an entire outer periphery of the valve casing. a diaphragm 34 that is airtightly fixed and separated into a valve chamber 38 through which gas passes through the valve casing 31 and a back pressure chamber 39 that is sealed; a movable valve body 33 that opens and closes the valve port 32a opened in the inner partition wall 32 from the side opposite to the diaphragm, and a movable valve body 33 that is provided between the movable valve body and the valve casing 31; A spring 36 is provided between the movable valve element 33 and the valve casing 31 to urge the movable valve element in a direction to contact the valve port 32a, and a coil 46 is provided between the movable valve element 33 and the valve casing 31 to urge the movable valve element into contact with the spring 36. It is characterized in that the back pressure chamber 39 is connected between the air supply port 18 in the inner shell 17 and the gas burner 10 through a communication pipe 29.

(Function) The opening degree of the proportional solenoid valve 30 not only changes depending on the current applied to the coil 46, but also increases in accordance with an increase in the pressure inside the back pressure chamber 39. When the amount of heat required for the gas bar 10 changes, commands from the electronic control device 60 to the proportional solenoid valve 30 and the electric fan 19 are issued simultaneously in parallel, but the rotation speed of the electric fan 10 responds with a delay from this command. Therefore, the amount of air blown to the inner shell 17 and the communication pipe 29
The pressure within the inner shell 17 in the vicinity of the opening also changes with a similar delay. This pressure introduced into the back pressure chamber 39 through the communication pipe 29 causes a delay in the change in the opening degree of the proportional solenoid valve 30, and therefore in the gas supply amount, similar to the amount of air blown by the electric fan 19. Even in a transient state where the required amount of heat changes, the gas supply amount and the air supply amount are always approximately proportional.

(Effects of the Invention) As described above, according to the present invention, even in a transient state where the amount of heat required for the gas burner changes, the amount of gas and air supplied to the bird is proportional to y. There is no risk of flame lift or resulting blow-off, and there is no risk of occasional incomplete combustion.

(Example) The present invention will be explained below using examples shown in the accompanying drawings.

As shown in FIG. 1, a main burner 1 consisting of a first partial burner 11 section and a second partial burner 14 arranged in parallel is installed at the bottom of the inner shell 17 of an instantaneous gas water heater type gas combustion appliance.
0 is provided, and an electric fan 19 is provided on the lower surface of the inner body 17. Combustion air from the electric fan 19 is sent into the inner shell 17 through the air supply port 18 opened on the lower surface of the inner shell 17, and the amount of gas ejected from the first and second main nozzles 23 and 24 is as follows: A proportionate amount of air is mixed as primary air and fed into each partial burner 11, 14 through each inlet 12.15, and this gas mixture is passed through the burner head 13.1 arranged above each partial burner 11.14. 16
It is ejected from the air, mixes with the remaining combustion air, and burns. The gas supply passage 20 to the main burner 1o is provided with an original solenoid valve 25 and a proportional solenoid valve 30 from the supply source side, and its downstream side is branched into first and second branch passages 21 and 22. .22 are provided with first and second switching solenoid valves 26, 27, respectively, and the first and second main nozzles 23, 24 are provided at each tip. Original solenoid valve 25
The switching solenoid valves 26 and 27 are simply opened and closed, and the proportional solenoid valve 30 will be described in detail later.

As shown in FIG. 1, a heat exchanger 50 is installed in the upper part of the inner shell 17.
A water supply pipe 51 is connected to one end thereof, and a hot water supply pipe 47 having a hot water tap 53 at the tip thereof is connected to the other end. When the hot water supply tap 53 is open, the water supplied from the water supply pipe 51 is heated by the main burner 10 when passing through the heat exchanger 50, reaches a predetermined hot water temperature, and is discharged from the hot water tap 53. The water supply pipe 51 is provided with a water flow sensor 63 such as a water flow switch that detects when the water flow rate has exceeded a predetermined minimum water flow rate, and the hot water supply pipe 52 is equipped with a hot water temperature sensor 62 such as a thermistor that detects the hot water temperature. It is provided.

Next, the proportional solenoid valve 30 will be explained. As shown in Figure 2 (
, the valve casing 31 of the proportional solenoid valve 30 is connected to each solenoid valve 25.
, 26. A case body 31a that is integral with the case body of 27, an annular intermediate case 31b and a back pressure chamber case 31c that are continuously and airtightly superposed on the upper side of this case body 31a, and an annular intermediate case 31b and a back pressure chamber case 31c that are airtightly superposed thereon. It is composed of an inverted cup-shaped magnetic case 31d, a lower cover 31e that airtightly covers the lower side of the case body 3'1a, and a cover plate 31f that airtightly covers the side surface of the case body 31a. are screwed together. The entire outer periphery of a diaphragm 34 made of synthetic rubber or the like is airtightly sandwiched between the case body 31a and the intermediate case 31b, and a valve chamber 38 through which gas passes through the inside of the valve casing 31 is formed.
and a sealed back pressure chamber 39. A valve port 32a is opened coaxially with the diaphragm 34 in a partition wall 32 that is integrally formed with the case body 31a and partitions the inside of the valve chamber 38 into an inlet side and an outlet side. The narrow diameter part of the upper end of the movable valve body 33 is inserted into the hole provided in the center of the thick part at the center of the diaphragm 34. Pressing spring 37a interposed between
It is coaxially attached to the diaphragm 34 with the thick inside sandwiched between it and the pressure receiving die 35 which is pressed by the diaphragm 34 . An umbrella part 33a that contacts the opening 32a from below to open and close the opening 32a is integrally formed at the lower part of the movable valve body 33.
3a is a spring 36 interposed between the lower cover 31e and the lower cover 31e.
, it is urged toward the opening 32a. Valve chamber 38
The inlet side (upper side in FIG. 2) of is communicated with the outlet side of the original solenoid valve 25 (located on the opposite side of the proportional solenoid valve 30 in FIG. 2) via a passage 20b, and the lower cover 31
An inlet side passage 20a of the original solenoid valve 25 is formed at e. Further, the outlet side (lower side in FIG. 2) of the valve chamber 38 is communicated with the first and second switching solenoid valves 26, 27 via a passage 20c.

As shown in FIG. 2, an electromagnetic drive device 40 that is a part of the proportional solenoid valve 30 and operates the movable valve body 33 is provided inside the magnet case 31d. Back pressure chamber case 31
An annular magnetic pole piece 42 made of iron, two annular magnets 41, and a yoke 43 made of iron are superimposed and clamped between C and the magnet case 31d via a wave washer 43a, and the inner circumference of the annular magnetic pole 42 is Lines of magnetic force are formed in the annular gap between the yoke 43 and the tip of the cylindrical portion at the center of the yoke 43. Movable valve body 3
A bobbin 45 made of synthetic resin is movably and loosely fitted into the cylindrical part at the center of the yoke 43 located coaxially with the yoke 3. The bobbin 45 is made of synthetic resin and extends downward through the gap where the lines of magnetic force are formed, and is inserted into the recess at the lower end of the bobbin 45. A small diameter portion of the upper end of the movable valve body 33 is inserted into and abuts on the upper end of the movable valve body 33, and a coil 46 is wound around the outer circumferential portion of the annular magnetic pole piece 42 above and below. Back pressure chamber case 31c
Two terminals 48 are provided hermetically through an insulator 47 that is hermetically fixed to the insulator 47, and each terminal 48 is connected to a flexible conductor 49.
It is connected to both ends of the coil 46 via.

One end of a communication pipe 29 is airtightly provided in the back pressure chamber case 31c, and the other end of this communication pipe 29 airtightly passes through the bottom plate of the inner body 17 to connect the back pressure chamber 39 to the back pressure chamber case 31c. Inner and inner body 17
It communicates with the vicinity of the air supply port 18 in the inner lower part. The communication pipe 29 is for introducing the air blowing pressure from the electric fan 19 into the back pressure chamber 39. Therefore, it is most efficient to open the other end of the communication pipe 29 near the air supply port 18 as in this embodiment. However, the opening may be made in any part of the space between the bottom plate of the inner shell 17 provided with the air supply port 18 and the bottom of the gas burner.

In such a proportional solenoid valve 30, the movable valve body 33 moves against the spring 36 in response to an increase in the applied current to the coil 46 that crosses the lines of magnetic force between the annular magnetic pole valve 42 and the yoke 43, thereby changing the opening degree. Not only does this increase, but also in response to an increase in the pressure in the pressure receiving chamber 39 acting on the upper surface side of the diaphragm 34, the movable valve body 33 moves and the opening degree increases. In addition, since the pressure on the inlet side of the valve chamber 38 acts on the lower surface side of the diaphragm 34, the proportional solenoid valve 30 can maintain the pressure in the valve chamber even when the current applied to the coil 46 and the internal pressure of the pressure receiving chamber 39 do not change. The movable valve body 33 moves and changes its opening degree in response to increases and decreases in the pressure of the gas source applied to the inlet side of the valve chamber 38, and the pressure on the outlet side of the valve chamber 38 is maintained at a predetermined level regardless of fluctuations in the pressure of the gas source. Equipped with a governor function to maintain pressure.

The electronic control device 60 that controls the operation of the instantaneous gas water heater includes:
As shown in FIG. 1, a hot water temperature setting device 61 and a hot water temperature sensor 6
2 and the water flow sensor 63 are connected, and the terminal 48 and the conductor 4
The coil 46 of the proportional solenoid valve 30 is connected through the solenoid 9, and the solenoid 25a, 26 of each solenoid valve 25, 26, 27 is connected to the coil 46 of the proportional solenoid valve 30.
a, 27a and the electric fan 19 are connected.

Next, the operation of the above embodiment will be explained. Electronic control device 60
When the power is turned on and the hot water tap 53 is opened, and the water flow rate exceeds the predetermined minimum water flow rate, the electronic control unit 60 operates each component based on a predetermined sequence, and first supplies gas Q to a small amount necessary for ignition. The first partial burner 11 is ignited and then the second partial burner 14 is ignited to start the instantaneous water heater. The water supplied from the water supply pipe 51 is heated by the heat exchanger 50 and then discharged from the hot water supply pipe 52. After startup, the electronic control unit 60 adjusts the discharge temperature detected by the hot water temperature sensor 62 to the hot water temperature setting device. The amount of gas supplied to the main burner 10 is controlled by controlling the current applied to the coil 46 of the proportional solenoid valve 30 so that the hot water temperature reaches the set temperature. The input power to the electric fan 19 is controlled so that the ratio between the supply amount and the air supply amount is maintained within a predetermined range.

When the electronic control unit 60 continuously decreases the current applied to the coil 46 and the input power to the electric fan 19 from time t1 to t2, the rotation speed of the electric fan 19 lags behind time t2 due to inertia. It does not decrease to the predetermined value until time t3 arrives. Therefore, the air supply amount does not decrease to a predetermined value until time t3 (as shown by the solid line A1 in FIG. The pressure also decreases continuously until reaching time t3, as shown by the solid line D1.

On the other hand, the proportional solenoid valve 30 responds to the current applied to the coil 46 with almost no delay if there is no fluctuation in the pressure inside the back pressure chamber 39, and its opening degree and gas supply amount are as shown in FIG. As shown by the dashed dotted lines C1a and Bla (at time t2, the actual opening degree and gas supply amount of the proportional solenoid valve 30 tend to reach a predetermined value), as shown by the solid line Di. As shown by the solid lines C1b and Bib in FIG.
The gas price supply amount shown by is very close to the broken line Blc indicating the proportional gas supply amount corresponding to the decrease in the air supply amount shown by the solid line A1, so the current applied to the coil 46 and the electric fan 19 are Even in a transient state where the input power rapidly decreases, the gas supply amount and air supply amount are always approximately proportional.

Similarly, between times t4 and t5, coil 46
When the applied current to the electric fan 19 and the input power to the electric fan 19 are continuously increased, the air supply amount increases as shown by the solid line A2 in FIG. , and the pressure in the back pressure chamber 39 also increases continuously until reaching time t6, as shown by the solid line D2.As a result, the actual gas supply amount does not increase to the value of the solid line A2, as shown by the solid line B2b. Broken line B2C proportionally corresponds to supply amount
Therefore, even in this transient state, the gas supply amount and the air supply amount are always approximately proportional.

In this embodiment, the electronic control device 60 sets the hot water temperature detected by the hot water temperature sensor 62 to the hot water temperature setting device 61.
Since the current applied to the coil 46 and the input power to the electric fan 19 are increased or decreased compared to the set temperature by
By introducing the pressure from the inner lower part into the back pressure chamber 39, the proportional relationship between the gas supply amount and the air supply amount can be maintained favorably even in a transient state.

In the above embodiment, a moving coil type electromagnetic drive device 40 is used, but the present invention can also be implemented using a fixed coil type electromagnetic drive device.

[Brief explanation of the drawing]

The attached drawings show an embodiment of the gas combustion equipment according to the present invention, in which Fig. 1 is an overall explanatory diagram, Fig. 2 is a sectional view mainly showing the structure of a proportional solenoid valve, and Fig. 3 shows changes in air supply amount, etc. FIG. Explanation of symbols 10... Gas burner, 13. 16... Burner head, 17... Inner shell, 18... Air supply port, 19... Electric fan, 29... Communication pipe, 30...・Proportional solenoid valve, 3
1... Valve casing, 32... Partition wall, 32a...
・Valve port, 33... Movable valve body, 34... Diaphragm, 36... Spring, 38... Valve chamber, 39...
Back pressure chamber, 40... Electromagnetic drive device, 46... Coil,
60...Electronic control device.

Claims (1)

[Claims] an inner shell in which a gas burner is installed; an air supply port that opens in the inner shell on the side opposite to the burner head of the gas burner; and an air supply port that continuously changes the degree of opening depending on the applied current to supply gas to the gas burner. a proportional solenoid valve that controls the amount of air supplied into the inner shell; an electric fan that is connected to the air supply port and whose rotation speed changes continuously according to input power to control the amount of air supplied to the inner shell; and the amount of gas supplied. In a gas combustion device, the gas combustion equipment comprises an electronic control device that controls the current applied to the proportional solenoid valve and the input power to the electric fan in a related manner so that the air supply amount changes proportionally in accordance with a change in the amount of air supplied. , the proportional solenoid valve includes a valve casing, a diaphragm whose entire outer periphery is airtightly fixed to the valve casing and which separates the valve chamber into a valve chamber through which gas passes through the valve casing and a sealed back pressure chamber; a movable valve body that is coaxially attached to the center and opens and closes a valve port opening in a partition wall in the valve chamber from the side opposite to the diaphragm, and a space between the movable valve body and the valve casing; a spring provided between the movable valve body and the valve casing to bias the movable valve body in a direction to abut the valve port; and a spring provided between the movable valve body and the valve casing to bias the movable valve body in a direction that urges the movable valve body to come into contact with the valve opening. 1. A gas combustion device comprising an electromagnetic drive device for moving the device against the pressure, wherein the back pressure chamber is communicated between the air supply port in the inner shell and the gas burner through a communication pipe.