JP2013170737A - Latent heat recovery type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a latent heat recovery type water heater capable of preventing drain scattering caused by the reverse flow of combustion gas during extinction.SOLUTION: A latent heat recovery type water heater includes: a combustion burner 8 for generating combustion gas by combustion; a primary heat exchanger 21 located on the combustion burner 8 to heat supplied hot water by receiving sensible heat of the combustion gas; a secondary heat exchanger 23 located on the primary heat exchanger 21 to heat supplied water by receiving latent heat of the combustion gas; a drain receiver 26 for partitioning the secondary heat exchanger 23 and the primary heat exchanger 21 from each other and receiving a drain generated from the secondary heat exchanger 23; a combustion fan 13 for supplying combustion air to the combustion burner 8 and blowing the combustion gas through the primary heat exchanger 21 and the secondary heat exchanger 23 to an exhaust port 25; and a control means 37 for controlling combustion and driving of the combustion burner 8 and the combustion fan 13. The control means 37 increases the rotational speed of the combustion fan 13 immediately before extinction.

Description

  The present invention relates to a latent heat recovery type hot water supply apparatus that prevents the drain from scattering to the primary heat exchanger due to a pressure difference during fire extinguishing.

  In the conventional latent heat recovery type hot water supply device, a primary heat exchanger is provided on the combustion burner, a secondary heat exchanger is provided on the primary heat exchanger, and the combustion gas of the combustion burner is exchanged from the primary heat exchanger to the secondary heat exchange. The sensible heat of the combustion gas is recovered by the primary heat exchanger during this time, and the latent heat is recovered by the secondary heat exchanger, and the secondary heat exchanger is recovered by this latent heat recovery. Since drainage was generated from the wastewater, a drain receiver for recovering the drain was provided between the secondary heat exchanger and the primary heat exchanger.

Japanese Patent No. 3675225

  By the way, in this conventional latent heat recovery type hot water supply device, in order not to increase the size, the secondary heat exchanger is installed in a narrow place and in order to improve efficiency, a plurality of pipes are stacked and installed. However, immediately after extinguishing the fire, the internal pressure of the secondary heat exchanger part is higher than the internal pressure of the primary heat exchanger part, and the combustion gas flows back to the primary heat exchanger side, and the drain receives the drain. However, it is carried by the combustion gas flowing backward without falling to the surface, and is scattered to the primary heat exchanger not subjected to the acid-resistant treatment, so that the primary heat exchanger is corroded.

  In order to solve the above-described problems, the present invention has a configuration in which, in particular, a combustion burner that generates combustion gas by combustion, and primary heat that is located on the combustion burner and heats hot water by receiving sensible heat of the combustion gas. An exchanger, a secondary heat exchanger that is positioned on the primary heat exchanger and receives the latent heat of the combustion gas to heat the feed water, and partitions between the secondary heat exchanger and the primary heat exchanger; A drain receiver that receives drain generated from the secondary heat exchanger, and a combustion fan that supplies combustion air to the combustion burner and blows the combustion gas through the primary heat exchanger and the secondary heat exchanger to the exhaust port. And a control means for controlling the combustion and driving of the combustion burner and the combustion fan, the control means increases the rotational speed of the combustion fan immediately before extinguishing the fire.

  According to this invention, the rotational speed of the combustion fan is increased by 10% from the current rotational speed immediately before extinguishing the fire, and the fire is extinguished after being driven for a few seconds so that the internal pressure of the primary heat exchanger part is higher than that of the secondary heat exchanger part. Since the pressure is high and the combustion gas does not flow backward, it is possible to reliably prevent the drain from splashing into the primary heat exchanger, so that the primary heat exchanger is not corroded and can always be used with peace of mind. It is.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows the latent-heat recovery type hot-water supply apparatus of one Embodiment of this invention. The block diagram of the principal part electric circuit. The flowchart of the principal part.

Next, a latent heat recovery type hot water supply apparatus according to an embodiment of the present invention will be described with reference to the drawings.
Reference numeral 1 denotes a latent heat recovery-type vaporization type oil hot water supply apparatus of the present embodiment, 2 denotes a vaporizer that vaporizes fuel oil such as petroleum, 3 denotes a vaporization heater that is provided in the vaporizer 2 and heats the fuel oil to a vaporizable temperature, 4 A vaporization temperature sensor 5 for detecting the temperature of the vaporizer 2, 5 is a mixing chamber that communicates with the vaporizer 2 and premixes the vaporized gas vaporized in the vaporizer 2 and primary air, and 6 is provided at the bottom of the mixing chamber 5 for mixing. A mixing chamber heater that heats the chamber 5, a mixing chamber temperature sensor 7 that detects the temperature of the mixing chamber 5, and a combustion unit that communicates with the mixing chamber 5 and burns the premixed gas premixed in the mixing chamber 5. A combustion burner 9 is a plurality of heat-absorbing fins projecting on the combustion burner 8 on the back surface of the vaporizer 2, and feeds back the combustion heat to the vaporizer 2 to maximize the energization amount of the vaporization heater 3 and the mixing chamber heater 6. It is to suppress.

  10 is a nozzle for spraying fuel oil on the vaporizer 2, 11 is an electromagnetic pump for pumping fuel oil to the nozzle 10 via an oil feed pipe 12, and 13 is a combustion fan, which is an inlet of the vaporizer 2 and a combustion burner 8 via an air passage 14. The combustion air sucked from the suction port 17 is supplied to the carburetor 2 as primary air for premixing, and the air chamber 16 is lateral to the carburetor 2. And is supplied as secondary air combusted by the combustion burner 8 from below the mixing chamber 5.

  Reference numeral 18 denotes a heat exchanger accommodated in the combustion chamber 19. The heat exchanger 18 collects sensible heat from the combustion gas generated by the combustion of the combustion burner 8 and heats the feed water flowing through the primary heat receiving pipe 20. It is composed of a tube-type primary heat exchanger 21 and a secondary heat exchanger 23 that recovers latent heat from the combustion gas after passing through the primary heat exchanger 21 and heats hot water flowing through the secondary heat receiving pipe 22. A primary heat exchanger 21 is disposed above the combustion burner 8, and a secondary heat exchanger 22 is disposed above the primary heat exchanger 21 via a communication port 24, and the primary heat exchanger 21, The combustion gas that has passed through the communication port 24 and the secondary heat exchanger 23 in this order is exhausted from the exhaust port 25 to the outside of the hot water supply device 1.

  26 is a drain receiver that recovers the drain that is generated when the water vapor in the combustion gas exchanges heat with the water flowing through the secondary heat receiving pipe 22 of the secondary heat exchanger 23 to a temperature below the dew point. The receptacle 26 is disposed above the primary heat exchanger 21 and below the secondary heat exchanger 23 and is arranged in parallel with the communication port 24. Here, the corrosion resistance that constitutes the secondary heat exchanger 23 is provided. A bottom plate of a housing (not shown) having a drain receiver 26 is provided. Reference numeral 27 denotes a drain pipe that leads to a neutralizing device 28 that neutralizes the strongly acidic drain recovered by the drain receiver 26 with a neutralizing agent (not shown) made of particles such as calcium carbonate. .

  29 is a water supply pipe for circulating water supplied from a water supply source to the heat exchanger 18, 30 is for circulating hot water heated by the heat exchanger 18, and hot water is supplied to a hot water tap (not shown) provided at a predetermined location. The hot water supply pipe 31 is a water supply bypass pipe branched from the water supply pipe 29, and the hot water supply water flows through the primary heat receiving pipe 20, the secondary heat receiving pipe 22, the water supply pipe 29, the hot water supply pipe 30, and the water supply bypass pipe 31. It constitutes a circuit.

  A mixing valve 32 is provided at a connection portion between the hot water supply pipe 30 and the water supply bypass pipe 31, mixes hot water from the hot water supply pipe 30 and water from the water supply bypass pipe 31, and has a variable mixing ratio. A water supply temperature sensor provided in 29 for detecting the water supply temperature, 34 a flow rate sensor provided in the water supply pipe 29 for detecting the flow rate, and 35 provided in the hot water supply pipe 30 for detecting the temperature of the hot water heated by the heat exchanger 18. A heat exchange outlet temperature sensor 36 is a hot water supply temperature sensor that is provided in the hot water supply pipe 30 and detects the temperature of the hot water mixed by the mixing valve 32.

  37 is built in the latent heat recovery type vaporization type hot water supply apparatus 1 and receives a signal of each sensor of the latent heat recovery type vaporization type hot water supply apparatus 1 mainly by a microcomputer, and receives the vaporizer heater 3, the mixing chamber heater 6 and the combustion. This control means 37 controls the drive of each actuator such as the fan 13, and the control means 37 has a timer function when the flow rate sensor 34 detects that the flow rate is less than the minimum operating flow rate, and burns for 3 seconds in this case for several seconds. The combustion of the burner 8 is continued, and the number of rotations of the combustion fan 13 during this period is increased by 10% from the current number of rotations before extinguishing the fire, so that the primary heat exchanger 21 side from the internal pressure on the secondary heat exchanger 23 side The internal pressure is increased to prevent the corrosion of the primary heat exchanger 21 due to the scattering of drain.

  A remote control 38 is communicably connected to the control means 37 and remotely controls the latent heat recovery vaporization type petroleum hot water supply apparatus 1. The remote control 38 instructs on / off operation of the latent heat recovery type vaporization type petroleum hot water supply apparatus 1. An operation unit 40 including an operation switch 39 and a hot water supply temperature setting switch for setting the hot water supply temperature is provided.

Next, the operation of the latent heat recovery type vaporized petroleum hot water supply device 1 of this embodiment will be described.
When the operation switch 39 of the remote control 38 is turned on, the control means 37 controls the vaporizer heater 3 based on the temperature detected by the vaporization temperature sensor 4 and mixes based on the temperature detected by the mixing chamber temperature sensor 7. The chamber heater 6 is controlled to preheat the vaporizer 2 and the mixing chamber 5, the temperature at which the vaporizer 2 can vaporize the fuel oil, for example, the temperature of the vaporizer 2 is maintained at 220 ° C. to 225 ° C. It will be in the standby state in which temperature is maintained at 125 to 130 degreeC. In this standby state, when a combustion request is generated, the burner 8 can be ignited quickly, and the power consumption during standby can be reduced by maintaining the necessary minimum temperature.

  In the standby state, when the hot water tap is opened and the flow rate sensor 34 detects a flow rate equal to or higher than the minimum operating flow rate and the control means 37 determines that a combustion request has occurred, the carburetor heater 3 and the mixing chamber heater 6 is forcibly turned on to improve the ignitability, the electromagnetic pump 11 and the combustion fan 13 are driven, and the vaporized gas and the primary air vaporized in the vaporizer 2 are premixed in the mixing chamber 5 and premixed. Gas is ejected from the burner 8 to start combustion.

  The combustion gas generated by the combustion of the combustion burner 8 circulates through the primary heat exchanger 21, passes through the primary heat exchanger 21, and then circulates through the secondary heat exchanger 23 from the communication port 24, thereby performing secondary heat exchange. After passing through the vessel 23, it is discharged from the exhaust port 25 to the outside of the latent heat recovery type vaporized petroleum water heater 1. Further, the water supplied from the water supply source is led from the water supply pipe 29 to the secondary heat receiving pipe 22 and circulates in order from the secondary heat receiving pipe 22 to the primary heat receiving pipe 20 where heat is exchanged with the combustion gas. The hot water that has been heated and led from the primary heat receiving pipe 20 to the hot water supply pipe 30 and adjusted to the hot water supply set temperature by adjusting the opening of the mixing valve 32 is finally supplied from the hot water tap.

  At this time, in the secondary heat exchanger 23, the water flowing through the secondary heat receiving pipe 22 and the combustion gas are subjected to heat exchange, and the strongly acidic drain generated by the water vapor in the combustion gas being below the dew point. Is recovered by the drain receiver 26, flows into the neutralization device 28 through the drain pipe 27, and is neutralized with the neutralizing agent.

Next, extinguishing the combustion burner 8 will be described with reference to the flowchart of FIG.
If the hot-water tap is now closed and the hot water supply flow rate becomes less than the minimum operating flow rate detected by the flow sensor 34 and the control means 37 determines that there is no combustion request (step S1), the process proceeds to step S2 in YES, and the timer in the control means 37 is set. The count of 3 seconds is started and the number of rotations of the combustion fan 13 that is currently rotationally driven is increased by 10%. Then, in step S3, it is determined whether the timer has counted 3 seconds. If YES, the combustion burner 8 is determined in step S4. Fire extinguishing.

  In this way, the secondary heat receiving pipe 22 is packed in a narrow space, and the fire can be extinguished while the internal pressure on the primary heat exchanger 21 side is increased from the secondary heat exchanger 23 side where the flow resistance is large and the internal pressure is high. The gas is smoothly exhausted from the exhaust port 25 without flowing backward, and the corrosion of the primary heat exchanger 21 due to the scattering of drain can be surely prevented, so that it can be used safely for a long time.

8 Combustion burner 13 Combustion fan 21 Primary heat exchanger 23 Secondary heat exchanger 25 Exhaust port 26 Drain receiver 37 Control means

Claims (1)

  A combustion burner that generates combustion gas by combustion, a primary heat exchanger that is located on the combustion burner and that receives sensible heat of the combustion gas to heat hot water, and latent heat of the combustion gas that is located on the primary heat exchanger A secondary heat exchanger that heats feed water by receiving the heat, partitioning the secondary heat exchanger and the primary heat exchanger, receiving a drain generated from the secondary heat exchanger, and the combustion burner A combustion fan that supplies combustion air to the exhaust gas and blows the combustion gas through the primary heat exchanger and the secondary heat exchanger to the exhaust port, and a control means that controls combustion and driving of the combustion burner and the combustion fan. The latent heat recovery type hot water supply apparatus is characterized in that the control means increases the rotational speed of the combustion fan immediately before extinguishing the fire.

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