KR100317840B1 - A device for sensing closing of supply and exhaust tubes of a forced flue type combustion equipment - Google Patents

Abstract

The present invention relates to a supply and exhaust pipe closing detection device of a forced supply / exhaust combustion device that is stable to prevent combustion abnormality for a long period of time without being affected by the difference between individuals of the pressure sensor, and an orifice (25) is provided in the supply container (5), The pressure difference is generated above and below the orifice 25, the communication pipes 26 and 27 are connected to the upstream and downstream sides of the orifice 25, and the pressure sensor 28 is provided at the connection part of the communication pipes 26 and 27 to burner. The amount of change in the detection value of the pressure sensor 28 after the start of the operation of the combustion fan 7 with respect to the detection value of the pressure sensor 28 at the time of the stop of the combustion fan 7 before the start of combustion in (2) is set to a threshold value. When it does not exceed, since combustion of the burner 2 is stopped and combustion is stopped before it becomes abnormal combustion, abnormal combustion is not generated.

Description

A device for sensing closing of supply and exhaust tubes of a forced flue type combustion equipment}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced exhaust type combustion device that sucks combustion air into a burner by using a blower and exhausts combustion gas. In particular, the closing of the supply and exhaust cylinder is detected before the occurrence of abnormal combustion, thereby ensuring the safety of the user. It relates to a safety device to secure.

Conventionally, for example, in a forced exhaust type combustion device that is widely used as a combustion device such as an FF gas hot air heater, combustion caused by combustion while inhaling combustion air from the outside by a blower (combustion fan). Since the gas is discharged outdoors, combustion can be performed without contaminating the indoor air.

However, even in such a forced supply / exhaust combustion apparatus, when an unexpected close of the exhaust cylinder occurs, noxious gas due to abnormal combustion is generated, and in some cases, there is a risk that noxious gas flows into the room. For this reason, for example, a closed detection device for an exhaust cylinder using a wind pressure switch is provided. When an abnormality is detected, combustion is stopped and safety is ensured so that abnormal combustion does not continue.

However, because the mechanical wind pressure switch operates only at the set pressure value, accurate closing detection is impossible when the operating point changes due to the difference between individual parts, or the operating point changes due to the change in the number of years of use. there is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a supply and discharge cylinder closing detection apparatus capable of reliably detecting the closing of the supply and exhaust cylinder with stable accuracy without being influenced by the individual differences of parts and the number of years of use, thereby ensuring safety. do.

1 is a schematic configuration diagram showing an FF gas-heated air conditioner to which the present invention is applied.

2 is a side view showing an installation state of the FF gas hot air heater according to the present invention.

3 is a rear view of the FF gas-heated air conditioner to which the present invention is applied.

4 is a simplified circuit diagram showing an oscillation circuit for the pressure sensor of the first embodiment of the present invention.

Fig. 5 is a characteristic diagram showing the relationship between the oscillation frequency and the pressure difference caused by the orifice of the oscillation circuit of the first embodiment of the present invention.

Fig. 6 is a flowchart showing the operation of the FF type gas warm air heater according to the first embodiment of the present invention.

Fig. 7 is a schematic diagram showing the configuration of the pressure sensor in the second embodiment of the present invention.

Fig. 8 is a schematic diagram showing the configuration of the pressure sensor in the third embodiment of the present invention.

9 is a flowchart showing the operation of the FF gas-heater of the fifth embodiment of the present invention.

Description of the main parts of the drawing

7 Combustion Fan (Blower) 2 Burner

5 supply cylinder 6 exhaust cylinder

25 Orifice 28 Pressure sensor (pressure detector)

30 Controller (Supply and exhaust cylinder closing detector of forced exhaust type combustion device, pressure value storage means before operation, pressure difference detection means, combustion stop means)

The present invention relates to a forced exhaust type combustion device which sucks combustion air into a burner by using a blower and exhausts combustion gas generated in the burner according to claim 1, wherein An orifice for generating a pressure difference between the upstream and downstream sides of the respective cylinders is arranged in the exhaust cylinder for evacuating the supply cylinder or the combustion gas, and the pressure difference between the gas pressure on the upstream side of the orifice and the gas pressure on the downstream side. Pre-operation pressure value storage means for installing a pressure detecting element for detecting a pressure value as a pressure value, and storing a pre-operation pressure value detected by the pressure detecting element before operation of the blower; and the pressure during operation of the blower. A change amount detecting means for detecting a change amount by comparing the pressure value during operation detected by the detecting element with the pre-operation pressure value, and by the change amount detecting means. And a combustion stop means for stopping combustion of at least the burner when the absolute value of the detected change amount does not exceed a predetermined threshold value.

2. The claim 2 of claim 1, wherein the combustion stop means sets the predetermined threshold value for stopping combustion of the burner to a large value as the rotation speed of the blower increases. It is characterized by.

The scope of claim 3 is based on claim 1 or 2, wherein the forced exhaust / exhaust combustion apparatus includes the indoor temperature detection means for detecting an indoor temperature and the temperature detected by the indoor temperature detection means. A heater having a temperature regulating control means for stopping and resuming burner burner and operation of the blower, wherein the pre-operation pressure value storing means resumes combustion of the burner and operation of the blower by the temperature regulating control means. When the pressure is reduced, the pre-operation pressure value detected by the pressure detecting element before the operation of the blower is stored again, and the pre-operation pressure value is updated.

Embodiment of the invention

1 shows a system configuration of an FF gas hot air heater in the forced exhaust / exhaust combustion apparatus of the present invention.

The FF gas-heated air heater is a combustion chamber 3 accommodating a burner 2, a heat exchanger 3a connected to the combustion chamber 3, and air suction and warm air in the main body case 1 installed indoors. The convection fan 4 which sends out is provided.

In the combustion chamber 3, an air supply cylinder 5 extending outside the main body case 1 is connected and connected, and the exhaust cylinder 6 extended outside the main body case 1 similarly connects the heat exchange unit 3a. It is connected and connected through. In addition, a supply fan 5 is provided with a combustion fan 7 for supplying combustion air to the burner 2 in the combustion chamber 3, and a combustion fan motor for rotating the combustion fan 7 ( 8) is connected.

As shown in Figs. 2 and 3, the air supply cylinder 5 and the exhaust cylinder 6 are formed concentrically so that the exhaust cylinder 6 is inward, and the open end thereof is It is led outside and the air supply port 5a and the exhaust port 6 of the combustion chamber 3 are formed by this.

The burner 2 in the combustion chamber 3 includes a fuel gas and an air supply pipe ejected from a plurality of nozzles 11 provided in a gas supply pipe 9 (fuel supply path) piped and introduced from the outside of the main body case 1 ( It consists of a plurality of burner single bodies 12 which suck and mix the combustion air introduced into the combustion chamber 3 in 5) and blow out the mixed air, and a burner ( The spark plug 13 for igniting 2) and a flame rod 14 (combustion detecting means) for detecting whether the burner 2 is not ignited or if a fire occurs. It is installed in the combustion chamber 3.

On the other hand, two open / close solenoid valves 15 and 16 and a gas proportional valve 17 are installed in the gas supply pipe 9.

The convection fan 4 is provided in the main body case 1 facing the suction port 18 formed in the rear part of the main body case 1, and is connected by the convection fan motor 19 for rotating it. . The convection fan 4 sucks the indoor air through the suction port 18 by the rotation, and simultaneously sucks the sucked air into the blow passage 20 in which the heat exchange part 3a is formed. It blows out and blows air heated at the heat exchange part 3a indoors from the blowout port 21 formed in the front part of the main body case 1. As shown in FIG.

On the other hand, the suction port 18 is equipped with a filter 22, and the blowout port 21 is provided with a louver 23 for adjusting the blowout direction of the warm air.

Moreover, the room temperature sensor 24 which detects room temperature is provided in the rear part in the main body case 1 facing the suction port 18. As shown in FIG.

In the FF gas-heated air conditioner having the above main configuration, an orifice 25 is formed in the air supply cylinder 5 on the upstream side of the combustion fan 7 for supplying combustion air to the combustion chamber 3. The orifice 25 is formed in the supply and discharge system of the burner 2 from the supply cylinder 5 including the combustion chamber 3 to the exhaust cylinder 6 when the combustion fan 7 is operated to generate airflow normally. The pressure difference between the pressure of the combustion air on the upstream side and the pressure of the combustion air on the downstream side is generated.

In the vicinity of the orifice 25 of the air supply cylinder 5, one of the upstream communication pipe 26 and the downstream communication pipe 27 communicating with the air supply cylinder 5 on the upstream side and the downstream side of the orifice 25, respectively. Each end is connected and opened, and the other end of each communication pipe 26 and 27 is connected to the pressure sensor 28 for detecting the pressure difference of the combustion air in these communication pipes 26 and 27. .

The pressure sensor 28 detects the pressure difference between the upstream side and the downstream side of the orifice 25 of the air supply cylinder 5 through the upstream side communication tube 26 and the downstream side communication tube 27, for example, A semiconductor device having a thin film whose capacitance changes due to pressure differences on both sides is used.

The pressure sensor 28 is provided with a partition wall or a similar isolation member in a casing for accommodating the thin film semiconductor element, so that both sides of the thin film semiconductor element are disposed in separate rooms, and each chamber in the casing has an upstream communication pipe. Each end of the 26 and downstream communication pipe 27 is opened.

The FF gas-heated air heater having the above configuration is provided with a controller 30 for performing the operation control, and an operating device 33 including an operation switch 31, a room temperature setting switch 32, and the like.

The controller 30 is composed of an electronic circuit including a microcomputer, and includes a spark plug 13, an open / close solenoid valve 15 and 16, a gas proportional valve 17, a combustion fan motor 18 and a convection fan motor. Each drive unit 19 is operated and controlled to perform ignition control, combustion control, and capability control.

In addition, safety control is performed to prevent abnormal combustion of the burner 2 in advance. To this end, the controller 30 is provided with a pressure detector 34 using the pressure sensor 28.

Hereinafter, the safety control regarding the closing of the air supply cylinder 5 and the exhaust cylinder 6 by the pressure detection part 34 and the controller 30 is demonstrated.

As described above, the pressure sensor 28 has an end portion of each of the upstream side communication tube 26 and the downstream side communication tube 27 opened in the air supply pipe 5 respectively opening into respective chambers facing each side of the thin film semiconductor element. The capacitance of the semiconductor element changes due to the pressure difference between the communication tube 26 and the communication tube 27.

In the pressure detection unit 34, as shown in Fig. 4, an oscillation circuit 35 which considers the thin film semiconductor element as a capacitor is formed, and the oscillation frequency of the oscillation circuit 35 is detected. Since the oscillation frequency of is determined according to the capacitance of the pressure sensor 28, the oscillation frequency corresponding to the pressure difference between each communication pipe 26 and 27 is obtained.

Here, in the thin film semiconductor element used as the pressure sensor 28, individual difference of capacitance and year difference of use appear. For this reason, it is sometimes impossible to accurately detect the pressure difference in each communication pipe 26 and 27 for the oscillation frequency of the oscillation circuit 35 comprised as mentioned above.

Therefore, in the present invention, when the pressure difference does not occur in the upstream side and the downstream side of the orifice 25 before the airflow due to the operation of the combustion fan 7 is generated in the supply and discharge system of the burner 2, The frequency is detected and the value is stored as a pre-operational pressure value at the time of pressure balancing. After that, when the combustion fan 7 is operated to generate airflow through the supply / exhaust system including the combustion chamber 3, an oscillation circuit ( The oscillation frequency of 35) is detected as a pressure value during operation and compared with the pre-operation pressure value, closing the supply / exhaust cylinder 5 or the exhaust cylinder 6 on the upstream and downstream sides of the orifice 25 depending on whether or not a normal pressure difference occurs. Detect.

For example, as illustrated in FIG. 5, the oscillation frequency of the oscillation circuit 35 detected after the combustion fan 7 is operated is determined as to whether or not the closing of the supply cylinder 5 or the exhaust cylinder 6 occurs. 5 mmH between the upstream side and the downstream side of the orifice 25 if there is a difference of 8 kHz or more as a threshold value with respect to the oscillation frequency of the oscillation circuit 35 in the state where the combustion fan 7 is stopped. _{When a} pressure difference of ₂ O or more is generated and it is determined that normal airflow is generated in the air supply pipe 5, and the difference in oscillation frequency is less than 8 kHz, normal air flow does not occur in the air supply pipe 5, and (5) Or it is determined that the closure occurs anyway in the exhaust pipe 6.

The safety control operation by the pressure detection by the pressure detector 34 and the controller 30 will be described below with reference to FIG. 6 along with the operation of the FF type hot air heater.

When the user instructs operation start by the operation switch 31 (YES in step S10), the operation stop of the combustion fan 7 (revolution number = 0 rpm) is checked (YES in step S11), and the oscillation circuit 35 The oscillation frequency is detected at, and this is set as a pre-operation pressure value (for example, 162 kHz in FIG. 5) (step S12). On the other hand, in this embodiment, the threshold value is made constant at 8 kHz.

Next, as the ignition control, the combustion fan motor 8 is first controlled to rotate the combustion fan 7 at a predetermined rotational speed of, for example, 3000 rpm, thereby allowing the combustion fan 3 to enter the combustion chamber 3 from the supply cylinder 5. Air supply is performed to prepurge the combustion chamber 3 (step S13). After the start of this prepurge, the closing operation of the air supply cylinder 5 and the exhaust cylinder 6 is started by comparing the pre-operation pressure values stored in the oscillation circuit 35 at the oscillation frequency (pressure during operation).

At any time, the amount of change in the operating pressure value to the pre-operation pressure value is calculated, and when the change amount is smaller than the threshold value (for example, 8 kHz) (YES in step S14), the air supply cylinder 5 or the exhaust cylinder 6 Is judged to be a closing error, and the pre-purge is stopped, and an abnormal sound generator (not shown) provided in the manipulator 33 is notified to indicate the closing error and the indicator (not shown) is performed. Not displayed), the operation is stopped (step S19).

If the closing abnormality is not detected during the pre-purging, after performing the pre-purging for a predetermined time, the combustion fan motor 8 is controlled to rotate the combustion fan 7 at a rotational speed of, for example, 1300 rpm, and ignition in this state. The plug 13 is driven, furthermore, the opening and closing solenoid valves 15 and 16 of the gas supply pipe 9 are opened, and a predetermined amount of fuel gas is supplied to the burner 2 for ignition of the burner 2. The gas proportional valve 17 is energized so that the burner 2 is ignited (step S15).

The controller 30 performs ignition detection in response to the combustion detection signal of the flame rod 14, and when ignition is detected (YES in step S16), the convection fan 4 passes through the convection fan motor 19. In the case of confirming that the engine is rotated and started to blow into the room and the combustion of the burner 2 is continued, the burner depends on the setting state of the room temperature setting switch 32 and the detection room temperature of the room temperature sensor 24. The combustion control of (2) is performed (step S17).

When the burner 2 continues to burn, the amount of change in the pressure value before the operation of detecting the pressure sensor 28 is always compared with the threshold value, and the change amount decreases and becomes smaller than the threshold value (step) In S18, it is determined that the closing of the air supply cylinder 5 or the exhaust cylinder 6 is abnormal, the open / close solenoid valves 15 and 16 are opened to stop combustion of the burner 2 (step S19), and the operation is stopped. At the same time, the closing abnormality is notified and displayed by an indicator.

As described above, according to the present invention, the combustion fan 7 operates the detection value of the pressure sensor 28 for detecting the pressure difference between the upstream side and the downstream side of the orifice 25 provided in the air supply pipe 5. Before closing, the closing abnormality is detected by comparing the change in the pre-operation pressure value of the in-operation pressure value detected by the pressure sensor 28 with the threshold value after the combustion fan 7 is operated. Since it is made so that the opening and closing detection can always be performed correctly, without being influenced by the difference between the individual objects of the pressure sensor 28.

In addition, even if the number of years of use of the pressure sensor 28 and the oscillation circuit 35 changes, the amount of change with respect to the detected value of the pressure sensor 28 before starting operation is always determined, and thus is not affected by the change of each member. Therefore, the close detection can always be carried out accurately.

Therefore, combustion can be stopped before the combustion abnormality of the burner 2 occurs.

Next, a second embodiment will be described with reference to FIG.

In the second embodiment, the upstream side communication pipes 26 and the downstream side communication pipes 27 are directly connected so as to communicate with each other, and these communication pipes 26 and 27 are bypasses for communicating both sides of the orifice 25. (26, 27) from the upstream side communication tube (26) to the downstream side communication tube (27) to the pressure detection chamber (28A) through which air flow passes in accordance with the pressure difference between the upstream side and the downstream side of the orifice (25). In the pressure detection chamber 28A, a heat generating resistor 28B made of a resistor or the like whose temperature is lowered by the airflow passing therein is disposed.

A voltage (direct current) is always applied to the heat generating resistor 28B, and the pressure difference according to the flow rate of the airflow is detected by detecting the voltage value across the heat generating resistor 28B according to the resistance value changed by the temperature. .

The voltage at both ends of the heat generating resistor 28B can be easily detected by a known method such as connecting a separate resistor in series.

Next, a third embodiment will be described with reference to FIG.

In the third embodiment, a thermometer 36 for detecting a temperature is provided in the vicinity of the pressure sensor 28 of the second embodiment. Based on the temperature detected by the thermometer 36, the output value of the pressure sensor 28 comprised by the heat generating resistor 28B is correct | amended, and the influence of the air supply temperature passing through the air supply pipe 5 is removed, and a more accurate safety device is provided. It is possible to

Next, the fourth embodiment will be described.

The magnitude | size of the air supply stream which generate | occur | produces in the air supply pipe 6 by the combustion fan 7 changes with the rotation speed of the combustion fan 7, The pressure difference which arises in the upstream and downstream of the orifice 25, It changes according to the rotation speed of the combustion fan 7.

In each of the above embodiments, the threshold is set constant in consideration of these changes, but more precisely, in order to operate as a safety device, the threshold is set in accordance with the rotation speed of the combustion fan 7.

At the time of setting the threshold value, the rotation speed of the combustion fan motor 8 which rotates and drives the combustion fan 7 is detected, and the threshold value is set to a large value as the rotation speed value increases. Alternatively, since the rotation speed of the combustion fan 7 is determined according to the combustion amount, the threshold value may be set as the value of the combustion amount data or the control data of the gas proportionality valve 17 increases.

A fifth embodiment will be described based on FIG.

In the first to fourth embodiments, the operation of the combustion fan 7 is set to the state before the start of operation, and the pre-operation pressure value is constant during operation. However, as the heater, the room temperature sensor 24 is detected during operation. When the temperature reached the set room temperature set by the room temperature setting switch 32 (YES in step S21), the combustion was once stopped (stop combustion by turning off the thermocouple) (step S22), and then the room temperature decreased. When the combustion is restarted at the same time (thermocouple on) (Step S 23), when the room temperature is maintained at the set temperature, the upstream side of the orifice 25 at the time of stopping the combustion, that is, when the combustion fan 7 is stopped. The difference in pressure between the downstream side and the downstream side may be read back to the pre-operation pressure value and updated.

According to this, since the operation is compared with the pre-operation pressure value at the time of stopping the combustion fan 7 just before the resumption, the judgment of the amount of change with the pressure value during the operation is not affected by the change in time, and the closing abnormality The detection is correct.

In the supply / exhaust cylinder closing detection device of the forced exhaust / exhaust combustion apparatus, in the case of claim 1, an orifice is disposed in the supply cylinder for sucking combustion air or the exhaust cylinder for exhausting combustion gas. A pressure detecting element is provided for detecting the pressure difference between the gas pressure on the upstream side and the gas pressure on the downstream side as a pressure value.

In the forced exhaust type combustion device having such a configuration, before the blower for sucking combustion air into the burner or exhausting the combustion gas generated in the burner is operated, the pre-operation pressure value detected by the pressure detecting element is before operating. It is stored in the pressure value storage means, after which the blower is operated to start combustion in the burner, and after the blower is operated, the pressure value during operation is detected by the pressure detecting element, and the pressure value during operation is stored. It is compared with the pre-operational pressure value.

If the change in the pressure value during operation from the pre-operation pressure value is detected by the change amount detecting means, and the supply and exhaust cylinders are not closed and are normal, the upstream side of the orifice in each cylinder is caused by the negative pressure generated by the rotational speed of the blower. There is a large pressure difference between the downstream side. Therefore, the absolute value of the amount of change between the detected pre-operation pressure value and the in-operation pressure value becomes larger than the predetermined threshold value. In this case, combustion of a burner is not stopped by a combustion stop means, but it continues to burn.

On the other hand, when the exhaust cylinder or the air supply cylinder is closed for some reason, no gas flow occurs in the gas passage connected from the air supply cylinder to the exhaust cylinder even when the blower is operated, and no upstream and downstream of the orifice in the cylinder are generated. There is no big pressure difference between the sides.

Therefore, the pressure difference becomes small, and the absolute value of the change amount compared with the pre-operation pressure value is small, and it does not exceed a predetermined threshold value. For this reason, the combustion stop means stops combustion of the burner at least.

As a result, when the supply or exhaust cylinders are closed, combustion does not continue, and abnormal combustion due to lack of combustion air is not caused, and generation of harmful gases can be prevented.

In claim 2, the combustion stop means sets the predetermined threshold value for stopping combustion of the burner to a large value as the rotation speed of the blower increases.

In normal operation where the supply or exhaust cylinders are not closed at the same time, the pressure difference between the upstream and downstream sides of the orifice varies in size depending on the flow rate of the gas flow into the supply or exhaust cylinder based on the rotation speed of the blower. .

In detecting the amount of change between the stored pre-operational pressure value and the in-operation pressure value, even when the flow rate of the gas flow is different, in order to prevent misjudgment, the predetermined threshold value is set to a small value to allow a margin. It is also good to give, but on the contrary, if abnormal combustion occurs, combustion may not be stopped.

Thus, in claim 2, since the threshold which becomes the comparative reference value of a change amount is set to a large value with the increase of the rotation speed of the blower which produces the gas flow in a cylinder, the rotation speed of a blower changes. Even in this case, according to the changed air flow, the closed state can be determined strictly from the change amount between the pre-operational pressure value and the in-operation pressure value, and the burner combustion can be reliably stopped before the occurrence of abnormal combustion, The combustion stop due to the misjudgement can be prevented.

In claim 3, after the burner combustion and the blower operation are stopped, the pre-operation pressure value is updated when the burner combustion and the blower operation are resumed, and the pressure value during the operation after the restart is immediately before the blower operation. Since it is compared with the pre-operation pressure value, the change amount can always be detected accurately without being influenced by the time-lapse error of the pressure detection element or the like.

Claims (3)

In a forced exhaust type combustion device in which combustion air is sucked into a burner by using a blower and exhausting combustion gas generated in the burner, the supply air for sucking combustion air or an exhaust cylinder for exhausting combustion gas, An orifice for generating a pressure difference is arranged on the upstream and downstream sides of each cylinder, and a pressure detecting element for detecting the pressure difference between the gas pressure on the upstream side and the gas pressure on the downstream side of the orifice is provided as a pressure value. At the same time, the pre-operation pressure value storage means for storing the pre-operation pressure value detected by the pressure detection element before operation of the blower, and the pre-operation pressure value detected by the pressure detection element during operation of the blower. The change amount detecting means for detecting the change amount compared with the pressure value, and the absolute value of the change amount detected by the change amount detecting means has a predetermined threshold value. When not exceeded, at least grade exhaust passage close detection device of the forced air supply and exhaust type combustion apparatus comprising a combustion stopping means for stopping the combustion of the burner. 2. The forced exhaust type combustion according to claim 1, wherein the combustion stop means sets the predetermined threshold value for stopping combustion of the burner to a large value as the rotation speed of the blower increases. Supply and exhaust cylinder closure detection device. 3. The forced exhaust / exhaust combustion apparatus according to claim 1 or 2, wherein the forced exhaust / exhaust combustion apparatus performs combustion of the burner and operation of the blower in accordance with the room temperature detection means for detecting the room temperature and the temperature detected by the room temperature detection means. A heater having a temperature regulating control means for stopping and restarting, wherein the pre-operation pressure value storage means is operated before the operation of the blower when the combustion of the burner and the operation of the blower are resumed by the temperature regulating control means. And a pre-operation pressure closing device for the forced exhaust type combustion device, characterized in that the pre-operation pressure value detected by the pressure detection element is stored again to update the pre-operation pressure value.