JP3070720B2 - Gas appliances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a gas appliance,
In particular, the present invention relates to a gas appliance for city gas having a structure for converting non-natural gas specifications to natural gas specifications.

[0002]

2. Description of the Related Art City gas includes various gas types (4A, 4A).
B, 4C, 5A, 5B, 5AN, 6A, 5C, 6B, 6
C, 7C) is being used, but in recent years, it has been converted to natural gas (13A, 12A) and is shifting. For this reason, each gas appliance is pre-installed with a structure and a control mechanism capable of shifting to natural gas specifications in order to cope with gas type conversion. Conventionally, in a gas water heater or the like that generates a large amount of heat, a plurality of sheet metal burners having a plurality of flame openings are arranged and a combustion air is supplied by a blower. In addition to replacing or removing the damper for changing the area of the air supply port arranged in the mouth, the plurality of gas ejection nozzles facing each air supply port are replaced. On the other hand, the control unit switches the gas supply amount control switch for changing the gas supply amount control characteristic of the proportional valve for adjusting the gas supply amount in accordance with the target heat amount and the air supply control characteristic of the blower. Will be

[0003] In such a gas type conversion operation, in order to exchange a plurality of nozzles facing an air supply port of a sheet metal burner, a manifold provided with the nozzles is controlled by a burner and gas supply to the burner. After removing from the gas control mechanism (gas control unit) consisting of an electromagnetic valve and a proportional valve, etc., each nozzle is replaced with a nozzle corresponding to natural gas, then the manifold is connected to the gas control mechanism again An operation is performed in which a new nozzle is fitted to the mouth to face the air supply port of the burner. At this time,
The packing that has been inserted into the fitting portion between the manifold and the connection port of the gas control mechanism must be replaced with a new packing to ensure airtightness and then inserted.

[0004]

In the conversion work to the natural gas specification, it is necessary to complete the conversion work in a short time for all gas appliances such as households in the conversion area. Planning is an important task. As described above, in the conventional gas type conversion work, a plurality of nozzles must be replaced, which is troublesome and takes a lot of time, and a plurality of nozzles must be prepared as parts. Is a problem.

The present invention provides an inexpensive gas type that can reduce the work time and reduce the burden on parts, etc., in a gas type conversion operation of a gas appliance for city gas from a non-natural gas type to a natural gas type. An object is to provide a gas appliance having a conversion structure.

[0006]

According to a first aspect of the present invention, there is provided a burner having a plurality of sheet metal burners arranged therein and a gas pressure adjusting means for adjusting a supply pressure of a fuel gas supplied to the burner. At least a gas control mechanism connected to a gas supply source, and a plurality of nozzles for gas ejection facing respective air supply ports of the plurality of sheet metal burners of the burner, wherein the gas control mechanism is connected. In a gas appliance having a manifold fitted to a mouth via a packing, the technical means is such that the packing is replaced with a packing with an orifice when a gas type is changed to natural gas.

According to the present invention having such a configuration, in the gas type conversion operation to natural gas, the manifold having the nozzles facing the supply ports of the plurality of sheet metal burners is removed from the burner and the gas control mechanism, and the gas control mechanism is removed. Replace the packing inserted at the connection between the and the manifold with a packing with an orifice and reassemble.

When the natural gas is supplied after the conversion of the gas type to natural gas, the gas pressure according to the target calorie is applied to the orifice of the packing with the orifice by the gas pressure adjusting means, and the flow rate is adjusted according to the target calorie. Natural gas is supplied to the burner. In the gas type conversion work to natural gas specifications,
Replace multiple nozzles on the manifold,
Since there is no need to perform a gas leak test at the nozzle mounting portion, the work can be completed in a shorter time than in the past.

According to a second aspect of the present invention, in the first aspect, the packing with an orifice includes a metal disk having an orifice formed at a central portion thereof, and a resin member having at least the orifice exposed and enclosing the metal disk. Technical means. According to a third aspect of the present invention, in the second aspect, the resin member has a thick portion on an outer peripheral portion of the metal disk. In claim 4, claims 2 to 4
The technical means is that the packing with orifices is formed such that at least the metal disk is symmetrical. Since the shape of the orifice, which has a great influence on the control of the gas flow rate, is symmetrical, it is not necessary to check the front and back sides when replacing the packing, and the packing can be replaced in a short time. According to a fifth aspect, in the first to fourth aspects, the gas pressure adjusting means is a governor proportional valve that regulates a secondary pressure according to a supplied current value.
Control means having a switching means for controlling the control amount of the governor proportional valve according to a gas type to be used, while controlling in accordance with a target heat amount determined in accordance with a set temperature or a load or the like. Technical means. On the other hand, the control means need only switch the control amount such as the current value characteristic of the governor proportional valve by the switching means. When the governor proportional valve is controlled according to the target heat quantity determined after the gas type conversion operation to natural gas, the gas pressure according to the control quantity is applied to the orifice of the packing with orifice, and the flow rate corresponding to the target heat quantity is increased. Natural gas is supplied to the burner.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on the following embodiments. FIG. 1 shows a schematic configuration of a gas water heater for city gas according to the present invention. The gas water heater includes a burner 1, a manifold 2, a gas control mechanism 3, a combustion unit such as a blower 10, a heat exchanger 6 for heating water by the combustion unit, an automatic water flow control device 61, and a water supply pipe thereof. And a control unit 7 including various sensors for controlling the combustion unit and the hot water supply unit.

The control unit 7 automatically heats water to a target temperature in accordance with the flow of water in the hot water supply unit.
When a remote controller is connected to the control unit 7, the temperature can be arbitrarily set by the remote controller at any time. When the remote controller is used without the remote controller, the temperature is fixed in advance by a temperature setting switch in the control unit 7.

The amount of heat generated by the burner 1 is determined by the governor proportional valve 33 of the gas control mechanism 3 in accordance with the required amount of heat calculated based on the set temperature and the detected temperature of the thermistor provided at the outlet of the heat exchanger 6. It is controlled by adjusting the current value. In FIG. 1, reference numeral 8 denotes a combustion chamber casing that houses the burner 1 and the heat exchanger 6, and reference numeral 9 denotes a water heater casing that houses the entire configuration of the gas water heater.

Hereinafter, the combustion section will be described in detail. As shown in FIG. 2, the burner 1 has a plurality of sheet metal burners 11 in which a plurality of horizontal U-shaped mixing passages are formed and a plurality of flame ports 11 a are formed in an upper layer. After mounting on the frame fittings 12, 13
V-shaped grooves 12b, 13 formed above and below
b, these sheet metal burners 11 are sandwiched from front and rear to be integrated. Air supply port 11b at the lower side of each sheet metal burner 11
The opening area is set by each air supply hole 12c formed in the frame fitting 12. Here, each air supply hole 12c
Is, for example, when using natural gas (12A, 13A)
The opening area is set such that the primary air for combustion corresponding to the supplied gas amount is appropriately supplied to each sheet metal burner 11 by the operation of the blower 10.

When the non-natural gas such as 6A or 6B is used, primary air for combustion corresponding to the supplied gas amount is appropriately supplied to the outside of the air supply hole 12c of the frame fitting 12 by the operation of the blower 10. In order to limit the opening area of the air supply port 11b of each sheet metal burner 11, the damper 14 having a plurality of openings 14a smaller than the air supply hole 12c 12c is disposed so as to be in close contact with the formation surface of the damper 14c.
Are fixed to the frame fitting 12 with screws together with the manifold 2 having a plurality of nozzles 21 facing each air supply port 11b of each sheet metal burner 11.

The manifold 2 joins a straight rod-shaped fuel dispersion pipe 22 having both ends closed, and a supply pipe 23 for supplying fuel gas to the fuel dispersion pipe 22 from a substantially perpendicular direction at an intermediate portion of the fuel dispersion pipe 22. The fuel distribution pipe 22 has a plurality of ejection ports 24 to which nozzles 21 for ejecting fuel gas are attached to the supply ports 11b of the plurality of sheet metal burners 11, respectively. , The supply pipe 23, FIG.
As shown in (1), the opposite end to the fuel distribution pipe 22 is closed, and a fuel inlet 25 is formed in the vicinity of the opposite end so as to open in the same direction as the jet port 24. In addition, each nozzle 21
Is used having a diameter corresponding to a preset type of city gas.

As shown in FIG. 4, the gas control mechanism 3
The two solenoid valves 31 and 32 are a valve assembly integrally formed with an electromagnetic governor proportional valve 33 and are provided upstream of the fuel inlet 25 of the manifold 2. The solenoid valves 31 and 32 are sequentially arranged from the upstream side.
An electromagnetic valve 32 and a governor proportional valve 33 are arranged, and a pressure detection chamber 35 having a connection port 34 for connecting the manifold 2 is provided on the downstream side (upper side in the figure) of the governor proportional valve 33.

The test chamber 35 is a section for checking the supply gas pressure regulated by the governor proportional valve 33 by an external pressure tester (digital manometer).
Has an inspection port 35 made sealable by a screw 35b.
a is provided.

A packing 4 for ensuring airtightness is inserted between the connection port 34 of the gas control mechanism 3 and the fuel inlet 25 of the manifold 2. Packing 4
It is used in the specification of non-natural gas city gas (for example, 6A, 6B, etc.). As shown in FIG. Made of a resin member such as synthetic rubber.

Non-natural city gas (for example, 6A, 6
4B), the flat surface 42 of the packing 4 is disposed on the connection port 34 side of the gas control mechanism 3 as shown in FIG. It is arranged on the entrance 25 side.

Next, a description will be given of a packing 5 with an orifice which is used in place of the above-mentioned packing 4 when the gas water heater for non-natural gas city gas having the above configuration is changed to a natural gas specification. The packing 5 with orifices is replaced and used instead of the packing 4 when the gas water heater is used in a natural gas specification.

As shown in FIG. 6, the packing 5 with an orifice is provided with an orifice 51 in the center, and a resin member 53 is formed by molding on the outside of a metal disk 52 of brass or the like on which the orifice 51 is formed. It was formed. The metal disk 52 is symmetrical, including the orifice 51.

The resin member 53 is provided on the outer peripheral side of the metal disk 52 with a thick portion 55 having an arc-shaped cross section.
The thick portion 55 is also symmetrical. Therefore, the packing 5 with the orifice is symmetrical, so that it is not necessary to check the front and back sides at the time of replacement work. As a result, it is possible to prevent an installation error in the field work at the installation location of the gas water heater.

Next, a configuration for switching the gas type in the control unit 7 will be described. The control unit 7
A target calorie is calculated based on the set temperature and the temperature detected by the thermistor, the blower 10 is controlled according to the calculated target calorie, and a fuel gas is supplied at an appropriate air-fuel ratio according to a supply state of combustion air. For this purpose, the rotation speed of the blower 10 is detected, and the governor proportional valve 33 is controlled with an energizing current value corresponding to the detected rotation speed.

In order to make the amount of gas supplied to the burner 1 correspond to each gas type, when determining the current value corresponding to the detected rotational speed, the current characteristics determined in advance for each gas type are determined. The current value needs to be determined based on the current value. Therefore, for each gas type, a data map of the energizing current value characteristic corresponding to the detected rotation speed is stored in advance, and the gas type changeover switch is operated, and the data of the energizing current value characteristic corresponding to the target gas type is stored. I select a map.

The gas type selection operation of the gas type changeover switch is performed by a plurality of dip switches 71 as shown in FIG.
ON / OFF combination (for example, 8
Type), but in any case, regardless of the type of gas used, in the conversion work accompanying the shift to natural gas use, the gas type changeover switch must be set to the natural gas specification in all cases, Conversely, the gas type changeover switch is not switched to a gas type other than the natural gas type.

For this reason, in this embodiment, in order to make it possible to easily operate the gas type changeover switch in a short time, a plurality of dip switches 71 for individually selecting and setting the gas type are provided. In order to make it possible to easily switch to the natural gas specification regardless of the setting position of these dip switches 71, a slide switch 72 for setting a natural gas specification which is larger and easier to operate is provided. By simply switching one slide switch 72 to the natural gas specification, it is possible to easily set the natural gas specification.

For this purpose, the storage memory for storing the data map of the energized current value characteristic is provided with a storage capacity twice as large as the conventional one, and the gas type corresponding to the set state by the combination of the plurality of DIP switches 71 is provided. A data map of the energizing current value characteristic and a data map storing the energizing current value characteristic of the natural gas specification in the setting state of all the combinations of the DIP switches 71 are stored.

Thus, in the slide switch 72,
A data map for individual setting of gas types by a plurality of DIP switches 71 and a data map of a current-current characteristic of a natural gas specification can be selected regardless of the combination setting state of the DIP switches 71. One of the two data maps of the data map is selected, and when the slide switch 72 selects the natural gas specification (for example, on), all the combinations of the dip switches 71 are set. When the data map of the current value characteristic of the natural gas specification is selected and the slide switch 72 is set to the individual setting side (for example, off)
In step (3), a data map of the energization current value characteristic of the gas type according to the combination setting state of the plurality of DIP switches 71 is selected.

Table 1 shows an example of the relationship between the setting state of the slide switch 72 and the data map of the selected current value characteristics for the combination setting state of the plurality of DIP switches 71.

[0030]

[Table 1]

As shown in Table 1, when the slide switch 72 for setting the natural gas specification is turned on, the dip switch 71 as an individual gas type switch is provided.
Regardless of the combination of ON and OFF, when the data map of the natural gas specification is always selected and the slide switch 72 for setting the natural gas specification is off, the individual gas type changeover switch The data map of the specification of the gas type according to the combination of ON and OFF of the DIP switch 71 is selected. Therefore, in the conversion work to the natural gas specification, the slide switch 7 for setting the natural gas specification is used.
It is only necessary to switch only 2 and the work is easy, and the work time can be reduced.

A governor proportional valve 33 for each gas type with respect to a target heat amount (detected rotation speed) obtained by selecting each data map by operating a dip switch 71 and a slide switch 72 as gas type changeover switches.
FIG. 8 shows an example of the current-carrying current value characteristics.

Next, the operation for changing the gas water heater for city gas having the above configuration to a natural gas specification when changing the gas type of city gas will be described below.

After turning off the power by closing the gas source plug of the gas pipe, unplugging the power plug or turning off the power switch of the remote controller, the front cover of the water heater casing 9 is removed, and Remove the front plate of the combustion chamber in front of the burner 1. The screws for fixing the manifold 2 and the damper 14 to the frame fitting 12 and the screws for fixing the manifold 2 to the gas control mechanism 3 are removed, and the manifold 2 and the damper 14 are removed.

The packing 4 inserted between the fuel inlet 25 of the manifold 2 and the connection port 34 of the gas control mechanism 3 is removed, and the packing 5 with an orifice previously attached to the gas water heater body is taken out. , Packing 5 with orifice is connected to fuel inlet 25 and connecting port 34
, And insert the manifold 2 again into the frame fitting 1
3 and the gas control mechanism 3 with screws. At this time,
The damper 14 removed above is not attached.

The slide switch 72 of the gas type changeover switch provided in the control unit 7 is switched to the natural gas specification side, the sealing screw 35b of the test port 35a is removed, and a digital manometer is connected thereto. Turn on the power by plugging in the power plug or turning on the power switch on the remote control, and open the main plug of the gas pipe.

After the hot water tap is opened and water is supplied to start combustion, the minimum combustion compulsory switch 73 of the control unit 7 is turned on, and it is confirmed with a digital manometer that the minimum gas pressure in the natural gas specification is attained. Minimum combustion forced switch 73
Is turned on, the maximum combustion forcing switch 74 of the control unit 7 is turned on, and it is confirmed by a digital manometer that the maximum gas pressure in the natural gas specification is obtained. After the confirmation, the maximum combustion compulsory switch 74 is returned to the original position.

If the minimum and maximum gas pressures cannot be obtained, the minimum gas pressure is adjusted to the set pressure of "small" by the capacity adjusting screw 36 provided in the gas control mechanism 3. Then, the maximum gas pressure is adjusted by adjusting the variable resistor 75 for the capacity “large” provided in the control unit 7.

Close the hot-water tap, stop water flow, and burner 1
Is stopped, the power is turned off, and the sealing screw 35b is returned to the pressure detection port 35a. At this time, the inspection port 35a
Remember to install the packing provided on the sealing screw to prevent gas leakage at

After turning on the power again and passing water through, it was confirmed that there was no gas leakage at the test port 35a and at the connection between the manifold 2 and the gas control mechanism 3, and then the burner 1 of the combustion chamber casing 8 was The work is finished by attaching the front plate of the combustion chamber at the front and the front cover of the water heater casing 9.

By performing the above gas type specification conversion, in the gas water heater, as shown in FIG. 9, the packing 5 with the orifice is connected between the fuel inlet 25 of the manifold 2 and the connection port 34 of the gas control mechanism 3. When the gas is supplied from the gas control mechanism 3 to the manifold 2, the flow rate of the gas is restricted by the orifice 51 of the packing 5 with an orifice. As a result, as shown in FIG. A smaller amount of gas is supplied to the burner 1 than the gas amount of the natural gas. However, since natural gas has a larger calorific value than non-natural gas of the same amount, the gas supply amount with respect to the target calorific value Even if the amount of gas decreases, the same amount of heat can be obtained as compared to before the gas type conversion. .

In this embodiment, the control unit 7 switches the slide switch 72 of the gas type changeover switch to the natural gas side. This is because the slide switch 72 has a different diameter corresponding to each type of non-natural gas. All non-natural gas models equipped with nozzles can be converted to natural gas specifications using the same packing 5 with orifices. When using a packing with a special orifice to convert from specifications to natural gas specifications,
There is no need to switch the current value characteristics of the governor proportional valve, and the conversion to natural gas specifications can be completed simply by replacing the packing with an orifice.

As described above, according to the present invention, it is not necessary to replace a plurality of nozzles in the combustion section in the conversion operation to the natural gas specification as in the prior art, and the manifold 2 is connected to the burner 1 and the burner 1. Since it is only necessary to remove the packing 4 from the gas control mechanism 3 and replace the packing 4 with the packing 5 with an orifice, the operation can be performed easily. Further, in the work, since the packing 5 with orifices is symmetrical, it is not necessary to check the insertion direction, so that the work can be performed promptly. In addition, since the combustion chamber casing 8 is opened when the manifold 2 is removed,
Cleaning such as removal of combustion products of the burner 1 can be performed, and the combustion environment after the gas type conversion operation can be improved. In addition, since the air supply holes 12c of the frame metal fittings 12 are previously adjusted to the specifications of natural gas, the damper 1
4 only needs to be removed, and there is no need to replace the damper 14.

Next, a description will be given of the operation detection of the minimum combustion compulsory switch 73 and the maximum combustion compulsory switch 74 operated for gas pressure detection in the above-described pressure adjustment work for the conversion to natural gas by the control unit 7. .

The minimum combustion forced switch 73 and the maximum combustion forced switch 74 are provided to control the governor in order to set the combustion amount of the burner 1 to the minimum combustion or the maximum combustion irrespective of the necessary heat amount calculated by the control unit 7 as described above. The energization current value of the proportional valve 33 is controlled to the minimum rotation speed in accordance with the rotation speed of the blower 10 corresponding to the minimum target heat amount, and is temporarily changed to the minimum current value or the maximum current value in the specification of the selected gas type. It is for doing. Therefore, after the gas type conversion operation, it is necessary to perform normal heat quantity control. On the other hand, it is necessary for the operator to easily determine whether the minimum combustion compulsory switch 73 and the maximum combustion compulsory switch 74 can be operated in the gas type conversion work.

In consideration of these contradictory necessities, in the present embodiment, as the minimum combustion forcing switch 73 and the maximum combustion forcing switch 74, a changeover switch (for example, a slide switch) that can be fixed to an on state and an off state, respectively. And the control unit 7 uses the burner 1
In the combustion detection state, the moment when each switch is operated is captured, and it is determined that each switch is operated.

Hereinafter, the operation of detecting each switch operation by the control unit 7 will be described with reference to FIG. When water is detected by opening the hot water tap (YES in step 100), regardless of the positions of the minimum combustion compulsory switch 73 and the maximum combustion compulsory switch 74, an initial state is set.
After the ignition control, normal combustion in which the amount of combustion is controlled in accordance with the required amount of heat is started (step 101).

When the minimum combustion forcing switch 73 is operated from off to on during normal combustion or during forcible maximum combustion to be described later and an on-edge is detected (YES in step 102), the 20-minute timer is started and forced forcibly. The minimum combustion is started (step 103), and if the on-edge of the minimum combustion compulsory switch 73 is not detected (step 1).
(NO in 02), the process directly proceeds to step 104.

Thereafter, at step 104, if the forced minimum combustion is being performed (YES), the forced minimum combustion switch 73
Is determined to be OFF, and the minimum combustion forcing switch 73 is determined.
Is off (YE in step 105).
S), clear the 20 minute timer (step 106),
After the forced minimum combustion is completed, the process proceeds to step 101, where normal combustion is performed again. If the minimum combustion forced switch 73 is not turned off during the forced minimum combustion (step 105).
Is NO), it is determined whether or not 20 minutes have elapsed since the start of the forced minimum combustion, and if 20 minutes have not elapsed (NO in step 107), the process proceeds to step 108. If 20 minutes have passed (step 1
(YES in 07), the forced minimum combustion is terminated, the routine proceeds to step 101, and normal combustion is performed again.

During the above-described normal combustion or during the forced minimum combustion, when the maximum combustion forcing switch 74 is operated from off to on and an on-edge is detected (YES in step 108), a 20-minute timer is started and forced forcibly. Maximum combustion is started (Step 109), and if the on-edge of the maximum combustion compulsory switch 74 is not detected (Step 10).
(NO in 8), the flow directly proceeds to step 110.

Thereafter, in step 110, if the forced maximum combustion is being performed (YES), the maximum combustion forced switch 74 is activated.
Is determined to be off, and the maximum combustion forcing switch 74 is determined.
Is off (YE in step 111).
S), clear the 20 minute timer (step 112),
After the completion of the forced maximum combustion, the process proceeds to step 101, where the normal combustion is performed again. If the maximum combustion compulsory switch 74 is not off during the compulsory maximum combustion (step 111).
Is NO), it is determined whether or not 20 minutes have elapsed since the start of the forced maximum combustion. If 20 minutes have passed (step 1
13, YES), the forced maximum combustion is terminated, the routine proceeds to step 101, and normal combustion is performed again.

In step 114, it is determined whether or not the water flow has been stopped. If the water flow has been stopped (YES),
If the combustion is stopped (step 115) and the water flow is not stopped (NO), the process proceeds to step 102, and the processing after step 102 is performed as described above.

By performing the above control operation, if either the minimum combustion compulsory switch 73 or the maximum combustion compulsory switch 74 is turned on during normal combustion, the ON operation is performed only for 20 minutes from that point. Forced minimum combustion,
If the other switches 73 and 74 are turned on during the forced minimum combustion or the forced maximum combustion, the forced combustion is performed according to the switch operated later.

After 20 minutes elapse after the switches 73 and 74 are turned on, the normal operation is automatically switched to the normal combustion mode. Regardless of whether normal combustion is performed regardless of whether or not the operator mistakenly neglects to turn off the switches 73 and 74 at the end of the conversion work,
In subsequent use, the user will not suffer inconvenience,
Normal use is possible.

In the above embodiment, a governor proportional valve is used.
Although a gas water heater with a blower is shown, like a bath burner with only a gas governor as a gas pressure adjusting means,
In other types of gas appliances that perform combustion with a constant calorific value and do not have control means for controlling the gas amount, similarly,
The gas type conversion operation can be completed simply by replacing the packing with the orifice. Further, the present invention may be a gas appliance such as a gas water heater, and the type of the gas appliance is not limited to the above-described types.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a gas water heater for city gas according to the present invention.

FIG. 2 is an assembly diagram showing a combustion section of the gas water heater according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of a supply pipe showing a fuel inlet of a manifold of the gas water heater of the embodiment.

FIG. 4 is a side view showing a connection port of a gas control mechanism of the gas water heater of the embodiment.

FIG. 5 is a cross-sectional view showing a packing used in a non-natural gas specification in a combustion section of the gas water heater of the embodiment.

FIG. 6 is a cross-sectional view showing a packing with an orifice used in a natural gas specification in a combustion section of the gas water heater of the embodiment.

FIG. 7 is a plan view showing a gas type changeover switch, a pressure regulation minimum combustion compulsory switch and a maximum combustion compulsory switch in the control unit of the gas water heater of the embodiment.

FIG. 8 is an energization current value characteristic diagram showing an example of an energization current value characteristic of a governor proportional valve for each gas type with respect to a target heat amount (detected rotation speed) in the embodiment.

FIG. 9 is a partial cross-sectional view showing a connection portion between a gas control mechanism and a manifold incorporating an orifice-containing packing in the embodiment.

FIG. 10 is a supply gas flow rate characteristic diagram showing a gas supply amount to a burner for each gas type with respect to a target heat amount (detected rotation speed) in the embodiment.

FIG. 11 is a flowchart for explaining the operation detection operation of the minimum combustion compulsory switch and the maximum combustion compulsory switch by the control unit of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 burner 11 sheet metal burner 11b air supply port 2 manifold 21 nozzle 3 gas control mechanism 33 governor proportional valve 34 connection port 4 packing 5 packing with orifice 51 orifice 52 metal disk 53 resin member 55 thick part 7 control unit (control means) 71 DIP switch (switching means) 72 Slide switch (switching means)

Continuation of front page (56) References JP-A-9-133351 (JP, A) JP-A-9-33015 (JP, A) JP-A-59-9244 (JP, A) JP-A-62-158918 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23N 1/00 115 F23K 5/00 301

Claims (5)

(57) [Claims] A gas control unit connected to a gas supply source, comprising: a burner in which a plurality of sheet metal burners are arranged; and a gas pressure adjusting unit for adjusting a supply pressure of a fuel gas supplied to the burner. A mechanism, comprising: a plurality of nozzles for gas ejection facing respective air supply ports of the plurality of sheet metal burners of the burner; and a manifold fitted to a connection port of the gas control mechanism via packing. A gas appliance characterized in that the packing is replaced with a packing with an orifice during a gas type conversion operation to natural gas. 2. The packing according to claim 1, wherein the packing with an orifice includes a metal disk having an orifice formed in a central portion, and a resin member including the metal disk with at least the orifice exposed. Gas appliances. 3. The gas appliance according to claim 2, wherein the resin member has a thick portion on an outer peripheral portion of the metal disk. 4. The gas appliance according to claim 2, wherein the packing with the orifice has at least the metal disk formed symmetrically. 5. The gas pressure adjusting means is a governor proportional valve that adjusts a secondary pressure according to an energized current value, and controls the governor proportional valve according to a target heat amount determined according to a set temperature or a load. 5. The gas according to claim 1, further comprising control means for controlling the control amount of the governor proportional valve according to the type of gas used. 6. Appliances.