JP2005291581A - Structure of heat exchanger for hot water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a heat exchanger for hot water capable of assuring combustion performance and heat exchange rate. <P>SOLUTION: This structure of the heat exchanger for hot water comprises a combustion chamber 2 formed in a cylindrical shape and having a water chamber 1 therearound, a burner 3 installed at the side wall 2a of the combustion chamber through the water chamber 1, and an exhaust gas chamber 4 adjacent to the water chamber top board 1a of the water chamber 1. A resistance body 6 is disposed in a large number of cylindrical flue tubes 5 connected between a combustion chamber top board 2b and the water chamber top board 1a. The resistance body 6 comprises a plate-like body 6a installed in the longitudinal direction of the flue tubes 5, a large number of semi-circular large plates 6b formed by bending to the plate-like body 6a at specified intervals in alternating directions, small plates 6c formed by bending to the opposite side of the large plates 6b through the large plates 6b and a step part 6e with a specified height, and a gas flow hole 6d allowing the combustion gas to pass therethrough. A gas passing clearance 7 is formed between the front and side of the small plates 6c and the passage wall 5a of the flue tubes 5, the combustion gas is passed through the gas passing clearance 7 to raise the combustion gas along the passage wall 5a. Thus, since a heat exchange area acts effectively, the heat exchange rate can be increased. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention mainly relates to a hot water heat exchanger mounted on a domestic oil water heater or a domestic hot water boiler.

  In general, oil water heaters and hot water boilers have a cylindrical water chamber. The water chamber has a combustion chamber at the lower part of the interior, and a top plate of the combustion chamber and a top plate of the water chamber. A large number of cylindrical smoke tubes are provided in between, and the top plate of the water chamber also serves as the bottom plate of the exhaust gas chamber having the exhaust tube. When the combustion gas is discharged from the combustion chamber through the smoke pipe, the passage wall which is the inner wall of the smoke pipe is heated, and the water in the water chamber comes from the combustion chamber side wall, the combustion chamber top plate, and the passage wall of the smoke pipe. Receives heat and becomes warm water.

  A burner is attached to the combustion chamber side wall constituting the inner wall of the water chamber, and a blower for blowing combustion air to the burner, a fuel pressurizing pump for supplying fuel from the oil tank to the burner, and The fuel sent by the pressurizing pump is sprayed into the combustion chamber as mist fuel by the spray nozzle. In addition, an ignition electrode for igniting the sprayed fuel and a high voltage generator for supplying a high voltage to the ignition electrode, a spark discharge is performed at the ignition electrode by the high voltage generated by the high voltage generator, Ignite the atomized fuel ejected from the spray nozzle.

  When the mist fuel is ignited by the spark of the ignition electrode, a flame blows out from the burner into the combustion chamber and burns in the combustion chamber, and the combustion exhaust gas is discharged from the exhaust pipe through the exhaust pipe through the exhaust pipe chamber. . At this time, the hot combustion gas exchanges heat between the wall surface of the combustion chamber and the passage wall of the smoke pipe, and the water in the water chamber is heated.

In addition, the smoke pipe is provided with a resistor that obstructs the flow of the combustion gas. Due to the presence of the resistor, the high-temperature combustion gas is not smoothly discharged, and the heat exchange rate is controlled by controlling the passage speed of the combustion gas. It has a role to improve. For this reason, when the combustion gas passes through the smoke pipe from the combustion chamber, it is possible to obtain hot water having a high temperature by exchanging heat with tap water sent into the water chamber or water that is forcedly circulated (see Patent Document 1).
Japanese Patent Laid-Open No. 2333942

  The demand for product miniaturization and cost reduction has been increasing year by year, and the size of the combustion chamber and water chamber has been reduced to achieve this, and the heat transfer area has been reduced by downsizing. An exchange is becoming necessary.

  Conventionally, the number of plates formed on the resistor is increased as much as possible to improve the heat exchange rate. However, this resistor greatly affects not only the heat exchange rate but also the burner combustion performance. If the number of plates is increased to reduce the combustion gas flow rate, there is a problem that the burner causes abnormal combustion.

  The heat exchange between the combustion gas passing through the smoke pipe and the water sent to the water chamber is performed at the passage wall of the smoke pipe, but the combustion gas passes through the gas flow hole of the resistor located in the center of the smoke pipe, so the combustion gas Has a poor heat exchange rate because it tends to flow near the center of the flue and cannot efficiently heat the passage wall of the flue. Increasing the number of resistor plates only increases the resistance of the combustion gas and does not increase the heat exchange rate so much, and it is difficult to satisfy both the heat exchange rate and the exhaust efficiency of the combustion gas. It was.

  Further, the resistor plate is formed in a semicircular shape and brought into contact with the passage wall of the smoke tube, and the semicircular plate is provided so as to have the same diameter as the radius of the smoke tube. Therefore, it is necessary to cut and raise the plate, and the plate is formed by bending the plate-like body while cutting it into a semicircular shape. This puts a heavy burden on the mold, and the mold is damaged and repaired or replaced in a short period of time. Was necessary, and the mold cost increased, leading to an increase in cost.

  The present invention solves the above-described problem. A combustion chamber 2 that has a cylindrical shape and has a water chamber 1 around it, a burner 3 that penetrates the water chamber 1 and is provided on the combustion chamber side wall 2a, Connected between the exhaust gas chamber 4 disposed adjacent to the water chamber top plate 1a, the combustion chamber top plate 2b, and the water chamber top plate 1a to allow the combustion gas to pass therethrough, and water and combustion gas are passed through the passage wall 5a. A large number of cylindrical smoke tubes 5 that perform heat exchange, and a resistor 6 disposed inside the smoke tube 5, the resistor 6 being a plate-like member 6 a provided in the longitudinal direction of the smoke tube 5, and the plate-like member The body 6a is composed of a large number of semicircular large plates 6b bent in alternate directions at regular intervals, and the large plate 6b of the resistor 6 has the same diameter as the radius of the smoke tube 5 and the passage wall 5a of the smoke tube 5 In the heat exchanger provided with gas circulation holes 6d through which the combustion gas passes between the large plates 6b. A small plate 6c that is bent to the opposite side of the large plate 6b is provided through a large plate 6b of the antibody 6 and a step portion 6e having a certain height, and the small plate 6c is provided with a radius of the smoke pipe 5 and a gas flow hole 6d. The gas passage gap 7 is formed between the front and side of the small plate 6c and the passage wall 5a of the smoke pipe 5, and the combustion gas that has passed through the gas circulation hole 6d is transferred by the small plate 6c. The combustion gas is guided to the gas passage gap 7 and flows along the passage wall 5a.

  The gas passage gap 7 formed between the passage wall 5a of the smoke pipe 5 and the small plate 6c of the resistor 6 is formed so that the side of the small plate 6c is narrow and the front is wide. The combustion gas that has passed through 6d is likely to go to the front side of the small plate 6c, and the combustion gas is likely to flow uniformly throughout the gas passage gap 7, so that the entire passage wall 5 of the smoke pipe 5 can be heated uniformly. .

  The resistor 6 is attached to the smoke pipe 5 so that the small plate 6c is located on the upstream side of the flow of the combustion gas, and the combustion gas is retained in the smoke pipe 5 by the large plate 6b that contacts the passage wall 5a and the step portion 6e. Since the portion 8 is configured, the combustion gas rising along the passage wall 5a of the smoke tube 5 is sent to the gas circulation hole 6d over the step portion 6e after the flow velocity is once weakened in the retention portion 8, so that the inside of the smoke tube 5 The passage speed of the flowing combustion gas could be controlled, and the heat exchange rate could be improved.

  In addition, since the lateral width of the gas flow hole 6f located at the lowermost part of the resistor 6 is shortened and the width of the portions left on both sides of the lowermost gas flow hole 6f is set to the plate-like body 6a, Thus, thermal deformation of the lower portion of the resistor 6 can be prevented.

  In addition, the resistor 6 is formed by punching the gas flow holes 6d while leaving the shapes of the large and small plates 6b and 6c, and forming the large and small plates 6b and 6c by bending, thereby reducing the burden on the mold. As a result, the number of repairs and replacements due to damage to the mold is remarkably reduced, and the cost can be reduced.

  In the present invention for solving the above-described problems, the resistor 6 disposed in the smoke pipe 5 includes a plate-like body 6a, a semicircular large plate 6b obtained by alternately bending a part of the plate-like body 6a, and the large plate 6b. And a small plate 6c bent in the opposite direction through a step 6e having a certain height, and a gas passage gap 7 is formed between the front and side of the small plate 6c and the passage wall 5a of the smoke pipe 5. The combustion gas rises along the passage wall 5a of the smoke pipe 5 when the combustion gas passes through the gas passage gap 7, and the heat exchange area works effectively to increase the heat exchange rate. I was able to.

  Further, the combustion gas that has passed through the gas flow hole 6d of the resistor 6 tends to flow to the side of the small plate 6c close to the gas flow hole 6d. Since it is configured to be wide and narrow on the side, the combustion gas can easily go to the gas passage gap 7 in front of the small plate 6c, and the combustion gas can pass through the gas passage gap 7 uniformly. Since the wall 5a is heated uniformly, the heat exchange area can be widened.

  Further, the small plate 6c of the resistor 6 is arranged on the upstream side of the flow of the combustion gas, and the staying portion 8 is constituted by the large plate 6b and the step portion 6e, so that the combustion rising along the passage wall 5a of the smoke pipe 5 Since the gas once stops at the staying portion 8 and then goes to the gas flow hole 8 beyond the step portion 6e, the combustion gas flowing in the smoke pipe 5 does not increase without increasing the number of large and small plates 6b and 6c provided in the resistor 6. The passage speed could be controlled, and the heat exchange rate could be increased without increasing the exhaust load.

  In addition, the lowermost portion of the resistor 6 near the combustion chamber 2 is most affected by heat. In the present invention, the lateral width of the gas flow hole 6f located at the lowermost portion of the resistor 6 is shortened, and the plate-like body is formed. Since the portion left on both sides of the lowermost gas flow hole 6f of 6a is widened to increase the strength, thermal deformation of the lowermost portion of the resistor 6 can be prevented, and a good combustion state is maintained over a long period of time. It became possible.

  Further, the resistor 6 of the present invention can be formed by bending the large and small plates 6b and 6c after punching the gas flow hole 6d while leaving the shape of the large and small plates 6b and 6c. Compared to the method of forming a semicircular plate by cutting and raising, the burden on the mold can be reduced, the cost for repair and replacement due to the damage of the mold can be suppressed, and the manufacturing cost can be reduced.

  This configuration will be described with reference to the drawings showing an embodiment. 1 is a water chamber composed of a heat exchanger can, 9 is an outer shell of a heat exchanger composed of an outer wall of the water chamber 1, and 2 is a cylindrical water chamber. 1 is a combustion chamber top plate that is an upper plate of the combustion chamber 2, and 1 a is a water chamber 1 at the upper end of the outer cylinder 9. The water chamber top plate is an upper plate, and the water chamber 1 is constituted by an outer body 9, a combustion chamber side wall 2a, a combustion chamber top plate 2b, and a space covered with the water chamber top plate 1a.

  In the embodiment shown in FIG. 1, 10 is a water supply pipe that leads tap water or circulating water supplied by a circulation pump to the water chamber 1, and 11 is hot water obtained by heating in the water chamber 1 to hot water at a predetermined location. A hot water supply pipe 12 is a temperature sensor provided on the outer body 9 while the water supply pipe 10 and the hot water supply pipe 11 are connected. 3 is a burner attached through the water chamber 1 through the combustion chamber side wall 2a, 13 is a combustion blower for supplying combustion air to the burner 3, and 14 is fuel from an oil tank (not shown) to the burner 3. It is a pressurizing pump for pumping.

  The hot water supply pipe 11 at the upper part of the heat exchanger is connected to a faucet of a bath or kitchen. When the faucet is opened, tap water is sent from the water supply pipe 10 to the water chamber 1 of the heat exchanger. When the water heater is in an operable state, the temperature sensor 12 detects the water temperature of the water chamber 1, and when the temperature sensor 12 detects a temperature lower than a temperature set by an operation unit (not shown), a combustion command is sent to the burner 3. Take out and boil the water in the water chamber 1 to the specified hot water temperature. When cold water flows into the water chamber 1 due to the use of hot water and the temperature sensor 12 detects a temperature below the specified hot water temperature, the operation of the burner 3 is started again, and the operation is specified while repeating the operation / stop of the burner 3 in this way. Maintains hot water temperature.

  15 is a burner top that reaches the combustion chamber 2 at the tip of the burner 3, 16 is a nozzle for spraying the fuel sent by the pressure pump 14 to the combustion chamber 2, and 17 is a mist sprayed from the nozzle 16. An ignition electrode for igniting the fuel. When a combustion command is issued to the burner 3, the combustion air is sent from the blower 13 to the burner 3, and the pressurizing pump 14 is operated to spray the atomized fuel from the nozzle 16. Then, spark discharge is performed from the ignition electrode 17 to ignite the atomized fuel and start combustion.

  In the heat exchanger shown in FIG. 1, 5 is a plurality of smoke tubes disposed between the combustion chamber top plate 2b and the water chamber top plate 1a, 6 is a resistor disposed in the smoke tube 5, and 4 is a water chamber. An exhaust gas chamber 18 formed in a space above the top plate 1a, 18 is an exhaust cylinder connected to the exhaust gas chamber 4, and the combustion flame sent from the burner 3 to the combustion chamber 2 is completely burned in the combustion chamber 2, While passing through the smoke pipe 5 with the resistor 6, the combustion gas velocity is suppressed and the exhaust gas chamber 4 is reached. The combustion gas collected in the exhaust gas chamber 4 is exhausted from the exhaust cylinder 18 to the outside.

  5a is a passage wall which is a portion for exchanging heat with combustion gas in the smoke pipe 5, 6a is a plate-like body constituting the resistor 6 disposed in the smoke pipe 5, and 6b is a certain interval from the plate-like body 6a. A large number of semicircular large plates formed by bending in alternate directions, 6d are gas flow holes formed in a plate-like body 6a formed in a portion where the large plate 6b is bent, and the large plate 6b is a radius of the smoke tube 5 And a semicircular shape having substantially the same diameter.

  6c is a small plate bent on the opposite side of each large plate 6b formed on the plate-like body 6a, and 6e is a step having a certain height formed between the large and small plates 6b and 6c. 6b and 6c are configured as a pair via a stepped portion 6e, and the resistor 6 has a large number of a pair of large and small plates 6b and 6c arranged on the plate-like body 6a at a predetermined interval. A gas flow hole 6d is disposed between the plates 6b and 6c.

  The small plate 6c has a shape smaller than the radius of the smoke pipe 5 and the lateral width of the gas flow hole 6d, and 7 is formed between the front of the small plate 6c and the passage wall 5a of the side smoke pipe 5. It is a gas passage gap.

  When the combustion gas enters the smoke tube 5 from below the smoke tube 5, the combustion gas hits the semicircular large plate 6b, passes through the gas flow holes 6d, and passes along the lower surface of the small plate 6c. It flows toward 5a, changes the flow at the passage wall 5a, becomes an upward flow along the passage wall 5a, and passes through the gas passage gap 7 formed between the small plate 6c and the passage wall 5a. Thus, the flow of the combustion gas moves in a zigzag manner in the smoke pipe 5, and at this time, the high-temperature combustion gas heats the water in the water chamber 1 by heating the passage wall 5a.

  The resistor 6 arranged in the conventional smoke tube 5 controls the flow of combustion gas only by the semicircular plate formed alternately, and expects the combustion gas to flow in a zigzag manner by the plate and the gas flow hole 6d. However, in actuality, the combustion gas that has passed through the gas flow hole 6d immediately changes to an upward flow and rises along the plate 6a at the center of the smoke pipe 5, so that the heat exchange rate as expected is obtained. I couldn't.

  Further, in order to increase the heat exchange rate with the structure of the conventional resistor 6, it is necessary to increase the number of plates. However, if the number of plates is increased and the passage speed of the combustion gas is decreased, the exhaust load increases. There is a problem that air cannot be supplied from the blower to the burner, causing air shortage combustion and causing soot generation, and even if the number of plates is increased within a range not deteriorating the combustion of the burner 3, the heat exchange rate is almost unchanged. It was not.

  On the other hand, in the present invention, the combustion gas surely flows along the passage wall 5a of the smoke pipe 5 by the action of the small plate 6c. Therefore, the passage of the smoke pipe 5 in which heat exchange between the combustion gas and water is actually performed. The wall 5a was easily heated, and the heat exchange area worked effectively to improve the heat exchange rate. If the combustion gas can flow through the passage wall 5a of the smoke pipe 5 in this way, the heat exchange rate is remarkably improved even if the passage speed of the combustion gas is the same, and the heat exchange rate of the burner 3 is maintained while maintaining the combustion performance. Improvement was realized.

  Further, it is considered that a large amount of the combustion gas that has passed through the gas flow hole 6d tends to flow into the gas passage gap 7 on the side of the small plate 6c close to the gas flow hole 6d. In the embodiment of the present invention shown in FIG. 2, the shape of the small plate 6c is rectangular so that the space between the small plate 6c and the gas passage gap 7 is wide at the front of the small plate 6c and narrow at the side. Formed. According to this structure, the amount of combustion gas passing through the gas passage gap 7 on the side of the small plate 6c is regulated, and the amount of combustion gas passing through the gas passage gap 7 in front of the small plate 6c is increased. Since the amount of combustion gas passing through the gap 7 can be made uniform and the entire passage wall 5a of the smoke pipe 5 can be heated uniformly, heat exchange can be performed in a wide range.

  Even in the configuration of the resistor 6 provided with the large and small plates 6b and 6c of the present invention, the exhaust load increases when the number of the large and small plates 6b and 6c is increased in order to increase the heat exchange rate. In the embodiment of the present invention shown in FIG. 3, the small plate 6c is provided on the upstream side of the flow of the combustion gas when the resistor 6 is attached to the smoke pipe 5, and 8 is a step portion with the large plate 6b. 6e is a stagnant part of the combustion gas formed between 6e and the combustion gas that has hit the large plate 6b once stagnates in the stagnant part 8 and then goes over the step part 6e to the gas circulation hole 6d. It is. In this way, since the passage speed of the combustion gas can be controlled by the staying portion 8 without increasing the number of large and small plates 6b and 6c, the heat exchange rate can be increased without increasing the exhaust load. It was.

  Further, the resistor 6 wants the outer edge shape of the large plate 6b to be as close as possible to the inner edge shape of the smoke pipe 5. However, if the large plate 6b is enlarged, the lateral width of the gas flow hole 6d formed in the bent portion of the large plate 6b. The width of the portions left on both sides of the gas flow holes 6d of the plate-like body 6a is narrowed, and the strength of the resistor 6 is reduced. 6f is a gas flow hole located at the lowermost part of the resistor 6, and in this type of heat exchanger, the lowermost part of the smoke pipe 5 near the combustion chamber 2 has the highest temperature, and the resistor 6 attached to the smoke pipe 5 is used. However, since the lowermost part is most susceptible to heat, the heat exchange rate in this part is extremely high. For this reason, the resistor 6 is most likely to undergo thermal deformation of the portions left on both sides of the lowermost gas flow hole 6f of the plate-like body 6a, and this portion may cause thermal fusing if used for a long period of time. is there.

  In the present invention, the horizontal width of the lowermost gas flow hole 6f is formed shorter than the horizontal width of the upper gas flow hole 6d, and the width of the portion left on both sides of the lowermost gas flow hole 6f of the plate-like body 6a is set. Since it was widely formed, the strength of the lowermost portion could be increased, and thermal deformation of the lowermost portion of the resistor 6 could be prevented even after long-term use.

  FIG. 5 shows an example of the manufacturing process of the resistor 6. First, the plate-like body 6 a is punched by a press while leaving the large and small plates 6 b and 6 c and the step portion 6 e. Next, after the large and small plates 6b and 6c arranged in the same direction on one side of the plate-like body 6a are formed by bending, the other large and small plates 6b and 6c are formed by bending.

  In order to control the flow of combustion gas by the resistor, it is necessary to bring the outer edge shape of the resistor plate close to the inner edge shape of the smoke pipe 5, and thus the conventional resistor is formed by cutting the plate. In the case of this cutting process, the portion of the plate-like body forming the plate is bent while being cut in an arc shape, so the burden on the mold is large, and there is a drawback that the mold is easily damaged, There was a problem that the number of exchanges increased and the mold cost increased.

  On the other hand, in the present invention, by drilling the gas flow hole 6d, the periphery of the small plate 6c and the arc portion of the large plate 6b can be formed, and the large plate 6b having a large shape can be formed. Since the resistor 6 can be formed by punching and bending, the burden on the mold can be reduced and the number of repairs and replacements of the mold can be reduced, and the manufacturing cost can be reduced. It became.

It is sectional drawing of the water heater which implements this invention product. It is a cross-sectional view of the main part showing the implementation state of the product of this invention. It is a longitudinal cross-sectional view of the principal part which shows the implementation state of this invention goods. It is a perspective view which shows the Example of this invention goods. It is a top view which shows the manufacturing process of this invention goods.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water chamber 1a Water chamber top plate 2 Combustion chamber 2a Combustion chamber side wall 2b Combustion chamber top plate 3 Burner 4 Exhaust gas chamber 5 Smoke pipe 5a Passage wall 6 Resistor 6a Plate body 6b Large plate 6c Small plate 6d Gas flow hole 6e Stage 6f Bottom gas flow hole 7 Gas passage gap 8 Retention part

Claims (5)

A combustion chamber 2 which is cylindrical and has a water chamber 1 around it;
A burner 3 penetrating the water chamber 1 and provided on the combustion chamber side wall 2a;
An exhaust gas chamber 4 disposed adjacent to the water chamber top plate 1a of the water chamber 1,
A number of cylindrical smoke tubes 5 connected between the combustion chamber top plate 2b and the water chamber top plate 1a to allow the combustion gas to pass through and to exchange heat between the water and the combustion gas in the passage wall 5a;
A resistor 6 disposed inside the smoke pipe 5;
The resistor 6 is a plate-like body 6a provided in the longitudinal direction of the smoke pipe 5,
The plate-like body 6a is composed of a large number of semicircular large plates 6b bent in alternating directions at regular intervals,
In the heat exchanger in which the large plate 6b of the resistor 6 has the same diameter as that of the smoke pipe 5 and contacts the passage wall 5a of the smoke pipe 5, and a gas flow hole 6d through which combustion gas passes is provided between the large plates 6b.
A small plate 6c that is bent to the opposite side of the large plate 6b through a step 6e having a certain height with the large plate 6b of the resistor 6;
The small plate 6c is set smaller than the radius of the smoke pipe 5 and the lateral width of the gas flow hole 6d, and a gas passage gap 7 is formed between the front and side of the small plate 6c and the passage wall 5a of the smoke pipe 5,
A structure of a heat exchanger for hot water, wherein the combustion gas that has passed through the gas flow hole 6d is guided to the gas passage gap 7 by the small plate 6c so that the combustion gas flows along the passage wall 5a.   The gas passage gap 7 formed between the passage wall 5a of the smoke pipe 5 and the small plate 6c of the resistor 6 is formed so that the side of the small plate 6c is narrow and the front is wide. 1. The structure of the heat exchanger for hot water according to 1.   The resistor 6 is attached to the smoke pipe 5 so that the small plate 6c is located on the upstream side of the flow of the combustion gas. In the smoke pipe 5, the large gas plate 6b contacting the passage wall 5a and the step portion 6e are used to store the combustion gas. The structure of the heat exchanger for hot water according to claim 1,   The lateral width of the gas flow hole 6f located at the lowermost portion of the resistor 6 is shortened, and the plate-like body 6a is set to have a wider width left on both sides of the lowermost gas flow hole 6f. The structure of the heat exchanger for hot water according to claim 1. The resistor 6 is formed by punching the gas flow hole 6d while leaving the shape of the large and small plates 6b and 6c, and bending the large and small plates 6b and 6c. The structure of the heat exchanger for hot water described in any of the above.

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