JP2010060221A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater capable of detecting respective clogging of a main heat exchanger and an auxiliary heat exchanger by a simple configuration. <P>SOLUTION: The water heater is equipped with a detection means 44 for detecting clogging of the auxiliary heat exchanger 8 and the main heat exchanger 4 by comparing a ratio of hot water supply output obtained by multiplying a supply water flow rate from a supply water flow rate sensor 17 on a temperature difference between a supply water temperature from a supply water temperature sensor 13 and an outlet temperature of the main heat exchanger 4 from a main heat exchange outlet temperature sensor 18, and auxiliary heat exchanger 8 output obtained by multiplying the supply water flow rate from the supply water flow rate sensor 17 on a temperature difference between the supply water temperature from the supply water temperature sensor 13 and an outlet temperature of the auxiliary heat exchanger 8 from an auxiliary heat exchange outlet temperature sensor 19, with a proper ratio stored beforehand in a storing means 45. Thus, efficient and favorable hot water supply can be carried out throughout a long period of time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hot water supply apparatus that detects clogging of an auxiliary heat exchanger and a main heat exchanger to improve safety.

Conventionally, in this type, the value obtained by subtracting the feed water temperature from the set temperature is multiplied by the feed water flow rate, and this is divided by the thermal efficiency to calculate the required heat, and the value obtained by subtracting the feed water temperature from the set temperature is multiplied by the feed water flow rate. By dividing this by the thermal efficiency, the actual amount of heat was calculated, and by comparing this, an abnormality of the combustion device could be detected in advance. (For example, see Patent Document 1)
JP-A-62-200133

  By the way, with this conventional device, even if the abnormality of the combustion device can be detected, it is not possible to detect clogging of the heat exchanger, and it is possible to detect separately the clogging of the auxiliary heat exchanger and the main heat exchanger separately. It was not possible.

  The present invention focuses on this point and solves the above-described problems. In particular, the configuration of the present invention includes a combustion burner that supplies combustion gas into the combustion chamber, an exhaust path that communicates with the combustion chamber and discharges combustion gas, and a combustion chamber. An auxiliary heat exchanger provided on the exhaust path side for supplying water from a water supply pipe to exchange heat with combustion gas, and closer to the combustion burner than the auxiliary heat exchanger for circulating hot water heated by the auxiliary heat exchanger. A main heat exchanger provided; a feed water temperature sensor for detecting a feed water temperature provided in the feed water pipe; and a main heat exchange outlet temperature sensor for detecting a main heat exchange outlet hot water temperature provided at an outlet of the main heat exchanger; The auxiliary heat exchanger outlet temperature sensor provided at the outlet of the auxiliary heat exchanger for detecting the auxiliary heat exchanger outlet hot water temperature, and the water supply flow rate sensor provided in the water supply pipe for counting the water supply flow rate, Feed water temperature by the feed water temperature sensor , The hot water output obtained by multiplying the temperature difference between the main heat exchanger outlet hot water temperature by the main heat exchanger outlet temperature sensor and the feed water flow rate by the feed water flow sensor, the feed water temperature by the feed water temperature sensor, and the auxiliary heat The ratio of the auxiliary heat exchanger output obtained by multiplying the temperature difference from the outlet hot water temperature of the auxiliary heat exchanger by the outlet temperature sensor by the feed water flow rate by the feed water flow rate sensor, and stored in the storage means in advance. A clogging detection means for detecting clogging of the auxiliary heat exchanger and the main heat exchanger by comparing with the appropriate ratio is provided.

  According to the present invention, when the auxiliary heat exchanger is clogged with soot, the amount of heat absorbed by the auxiliary heat exchanger is reduced, so that the ratio of the auxiliary heat exchanger to the total hot water supply output is detected, and the main heat exchange is also detected. If the main heat exchanger is clogged with firewood first, if the main heat exchanger is clogged with firewood, sufficient heat exchange cannot be performed, so the exhaust temperature rises, and the heat absorption of the auxiliary heat exchanger located downstream of this main heat exchanger Therefore, it is detected by increasing the ratio of the auxiliary heat exchanger to the total hot water supply output, and in any case, by early detection, it is notified by stopping the combustion or displaying on the display unit, It is intended to improve safety by preventing combustion burner failures and heat exchanger burnout, and without the need for additional special parts, uses the characteristics of the auxiliary heat exchanger according to the installation position. Can be detected, and it is cheap and reliably detected There are those that can be used with confidence for a long time.

Next, an embodiment of the present invention will be described with reference to the drawings.
Reference numeral 1 denotes a water heater main body, which is provided with a combustion chamber 3 having a gun type combustion burner 2 attached downward at the upper end, and further inside the combustion chamber 3 close to the combustion burner 2. 2 is provided with a finned main heat exchanger 4 for recovering sensible heat of combustion gas generated by combustion of No. 2.

  5 is a communication path that connects the bottom of the combustion chamber 3 to one end, and an exhaust path 7 that has an exhaust port 6 at the top communicates with the other end. The combustion gas from the combustion chamber 3 is U-turned through the communication path 5. The gas is discharged from the exhaust port 6 through the exhaust path 7.

  8 is an auxiliary heat exchanger with fins for recovering the latent heat of the combustion gas provided in the exhaust passage 7 side of the main heat exchanger 4 in the combustion chamber 3, and a water supply pipe 9 is connected to one end to heat the water supply. After that, it is circulated to the main heat exchanger 4 through the connecting pipe 10 at the other end and the winding pipe 11 on the outer periphery of the combustion chamber 3, and further heated and circulated through the hot water supply pipe 12 to each hot water tap (not shown). ) Is supplied with hot water.

  Reference numeral 13 denotes a feed water temperature sensor comprising a thermistor provided in the vicinity of the feed port 14 of the feed water pipe 9 for detecting the incoming feed water temperature, and feeds the feed water to the mixing valve 15 of the hot water supply pipe 12 on the downstream side. A water supply bypass pipe 16 and a water supply flow rate sensor 17 that counts the water supply flow rate are provided further downstream of the water supply bypass pipe 16.

  18 is a main heat exchange outlet temperature sensor comprising a thermistor provided in the hot water supply pipe 12 in the vicinity of the outlet of the main heat exchanger 4, and detects the hot water temperature heated by both the auxiliary heat exchanger 8 and the main heat exchanger 4. 19 is an auxiliary heat exchange outlet temperature sensor which is also a thermistor provided in the connecting pipe 10 near the outlet of the auxiliary heat exchanger 8, and detects the hot water temperature heated by the auxiliary heat exchanger 8 alone. To do.

  Reference numeral 20 denotes an overpressure relief valve attached to the hot water outlet 21 of the hot water supply pipe 12. The hot water supply pipe 12 upstream of the overpressure relief valve 20 is proportional to the hot water temperature sensor 22 including a thermistor for detecting the hot water temperature. A mixing valve 15 for mixing the water supplied from the water supply bypass pipe 16 and the hot water supply to make hot water at a set temperature is provided. Further, in the vicinity of the main heat exchange outlet temperature sensor 18, hot water supply abnormality is provided. A hot water supply abnormal stop thermo 24 that detects and stops hot water supply is provided.

  A nozzle 25 is provided in the combustion burner 2 and sprays the fuel oil supplied from the oil feed pipe 26 and burns in the combustion chamber 3 while mixing with the combustion air supplied from the combustion fan 27. The oil pipe 26 includes an oil filter 28, an oil electromagnetic valve 29, and an electromagnetic pump 30, and a nozzle 25 having an oil proportional valve 31 and an oil temperature thermistor 32 is interposed between the oil electromagnetic valve 29 and the electromagnetic pump 30. The return pipe 33 is connected.

  Reference numeral 34 denotes a neutralization tank provided below the combustion chamber 3 and the exhaust path 7. The strongly acidic drain water generated by the latent heat recovery by the auxiliary heat exchanger 8 is collected by the collection pipe 35 and neutralized. A water level sensor 37 for detecting the water level and an oil sensor 38 for detecting the mixed oil are provided for draining from the drain pipe 36.

  39 is a burner thermo that detects abnormal heating of the combustion burner 2, and 40 is an exhaust thermo that detects abnormal heating of the exhaust passage 7.

Next, a principal block diagram of the electric circuit shown in FIG. 2 will be described.
Reference numeral 41 denotes a control circuit of the hot water supply body 1 composed of a microcomputer. The control circuit 43 receives the information from the various parameters described above, controls the combustion and hot water drive circuit 42, the clogging detection means 44, the storage means 45, etc. It is configured.

  The clogging detection means 44 is connected to the feed water temperature sensor 13 and the feed water flow rate sensor 17, the main heat exchange outlet temperature sensor 18 and the auxiliary heat exchange outlet temperature sensor 19 on the input side, and the drive circuit 42 and the display on the output side. A circuit 46 is connected, and every time the hot water supply operation is started, the temperature difference between the hot water temperature by the hot water temperature sensor 13 and the hot water outlet temperature of the main heat exchanger 4 by the main heat exchanger outlet temperature sensor 18 is counted from the start of hot water supply. The temperature of the hot water supply output obtained by multiplying the feed water flow rate by the feed water flow rate sensor 17, the feed water temperature by the feed water temperature sensor 13, and the outlet hot water temperature of the auxiliary heat exchanger 8 by the auxiliary heat exchanger outlet temperature sensor 19 This appropriateness is stored from the storage means 45 that stores the ratio of the output of the auxiliary heat exchanger 8 obtained by multiplying the difference by the feedwater flow rate by the feedwater flow rate sensor 17 and the appropriate ratio obtained in advance through experiments or the like. Compared call rates, and detects clogging of the auxiliary heat exchanger 8 and main heat exchanger 4.

  That is, in the clogging detection means 44, {(auxiliary heat exchanger outlet hot water temperature−feed water temperature) × feed water flow rate} ÷ {(main heat exchanger outlet hot water temperature−feed water temperature) × feed water flow rate}. 0.03 to 0.10 (exceeding 3% to less than 10%), and clogging of the auxiliary heat exchanger 8 is a ratio of 0.03% (3%) or less, while clogging of the main heat exchanger 4 Then, the ratio is 0.10 (10%) or more, and the hot water supply is stopped by controlling the drive circuit 42 via the drive control means 43, and the auxiliary heat exchanger 8 and the main heat exchange are displayed in the display circuit 46. The fact that the clogging of the heat exchanger 4 has occurred is displayed separately, and a user is called to inform the user that it is necessary to clean the auxiliary heat exchanger 8 and the main heat exchanger 4.

Next, the operation of this embodiment will be described.
When hot water supply is started at an appropriate location and hot water supply is started, the hot water flow sensor 17 detects this hot water flow and the combustion burner 2 starts to combust. 3 is connected to the communication path 5 to make a U-turn and flows into the exhaust path 7 and is exhausted from the exhaust port 6 above the exhaust path 7. In the combustion chamber 3, first, auxiliary heat is supplied via the water supply pipe 9. The feed water flows into the exchanger 8, and the hot water whose temperature has been raised by heat exchange with the combustion gas flows into the main heat exchanger 4 through the connecting pipe 10 and the winding pipe 11, where it is heated to a higher temperature. Then, hot water is supplied by mixing to a set temperature by the mixing valve 15 of the hot water supply pipe 12.

  Further, the auxiliary heat exchanger 8 recovers the latent heat of the combustion gas to generate strongly acidic drain water. This drain water is collected in the neutralization tank 34 below the combustion chamber 3 by the collection pipe 35. Are collected, neutralized with a neutralizing agent, and drained from the drain pipe 36.

  Next, the detection of clogging of the auxiliary heat exchanger 8 and the main heat exchanger 4 will be described with reference to the flowchart shown in FIG. 3. Hot water supply is started, the feed water temperature sensor 13 detects the feed water temperature in step 47, and the feed water flow rate sensor 17. Counts the flow rate, the main heat exchanger outlet temperature sensor 18 detects the outlet hot water temperature of the main heat exchanger 4, the auxiliary heat exchanger outlet temperature sensor 19 detects the outlet hot water temperature of the auxiliary heat exchanger 8, The clogging detection means 44 performs the calculation.

  And it progresses to step 48, it is judged whether the ratio of a calculation result is 0.03-0.10, and it becomes an appropriate ratio in YES, and it continues hot water supply, and in NO, it progresses to step 49 and a calculation result is 0.03. If YES, the process proceeds to step 50 where it is determined that the auxiliary heat exchanger 8 is clogged, and this is displayed on the display circuit 46 and the hot water supply is stopped. If NO, the process proceeds to step 51. It is determined whether the calculation result is 0.10 or more. If YES, the routine proceeds to step 52 where it is determined that the main heat exchanger 4 is clogged, and this is displayed on the display circuit 46 and hot water supply is stopped.

  As a result, it is possible to prevent the auxiliary heat exchanger 8 and the main heat exchanger 4 from being burned out, to prevent inefficient hot water supply operation in which the heat exchange efficiency is lowered, and to prevent abnormal combustion and abnormal heating due to clogging. It can be reliably prevented and can be used safely and safely for a long time.

The schematic block diagram of the hot water supply apparatus which attached | subjected one Embodiment of this invention. The principal part block diagram of the same electric circuit. The flowchart of the principal part.

Explanation of symbols

2 Combustion Hana 3 Combustion Chamber 4 Main Heat Exchanger 8 Auxiliary Heat Exchanger 9 Water Supply Pipe 12 Hot Water Supply Pipe 13 Water Supply Temperature Sensor 17 Water Supply Flow Rate Sensor 18 Main Heat Exchange Outlet Temperature Sensor 19 Auxiliary Heat Exchange Outlet Temperature Sensor 44 Clogging Detection Means 45 Storage means 46 Display circuit

Claims (1)

  A combustion burner for supplying combustion gas into the combustion chamber, an exhaust path communicating with the combustion chamber and exhausting the combustion gas, and water supplied from a water supply pipe provided on the exhaust path side in the combustion chamber flows to exchange heat with the combustion gas. An auxiliary heat exchanger, a main heat exchanger provided closer to the combustion burner than the auxiliary heat exchanger through which hot water heated by the auxiliary heat exchanger flows, and a water supply temperature provided in the water supply pipe A feed water temperature sensor, a main heat exchange outlet temperature sensor provided at the outlet of the main heat exchanger for detecting the main heat exchange outlet hot water temperature, and an auxiliary provided at the outlet of the auxiliary heat exchanger for detecting the auxiliary heat exchange outlet hot water temperature. What is provided with a heat exchange outlet temperature sensor and a water supply flow rate sensor that is provided in the water supply pipe and counts a water supply flow rate, wherein the water supply temperature by the water supply temperature sensor and the main heat exchanger by the main heat exchange outlet temperature sensor The temperature difference from the outlet water temperature The difference between the hot water supply output obtained by multiplying the feed water flow rate by the feed water flow rate sensor, the feed water temperature by the feed water temperature sensor, and the outlet hot water temperature of the auxiliary heat exchanger by the auxiliary heat exchanger outlet temperature sensor Clogging of the auxiliary heat exchanger and the main heat exchanger by comparing the ratio of the auxiliary heat exchanger output obtained by multiplying the feed water flow rate with the appropriate ratio stored in advance in the storage means A hot water supply apparatus characterized by comprising clogging detecting means for detecting.

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