JP4130430B2 - Hot water generator - Google Patents

Description

The present invention, silica is removed from the tap water, to the hot water generating device for preventing adhesion of the scale of the hot water generator.

  Tap water and groundwater (hereinafter referred to as “tap water”) contain various components according to topography and geology, and examples thereof include calcium and magnesium. When the tap water is heated and used as warm water, these components may become a problem. This is because when tap water is heated for a long time with a water heater or the like, components such as calcium contained in the tap water are deposited as scale.

  The deposited scale adheres to and accumulates in a portion where the cross-sectional area of the water supply pipe and the drain pipe connected to the water-refrigerant heat exchanger of the water heater is narrow and a section where the cross-sectional area of the water circulation portion of the heat exchanger is narrow. As a result, clogging may occur in a portion where these cross-sectional areas are narrow.

Considering this, the conventional heat pump hot water heater (see Patent Document 1) is provided with means for detecting clogging of the scale deposited in the water-side flow path, and when clogging is detected, tap water is supplied to the water side. The output of the water pump that circulates in the flow path is increased.
JP 2004-144445 A

  The above conventional example has room for improvement in the following points. First, it is not questionable whether the scale can be removed simply by increasing the output of the water pump and increasing the amount of circulating water. In addition, the cost increases due to the arrangement of the detecting means.

Second, depending on topography and geology, tap water may contain a relatively large amount of silicon oxide (SiO or SiO ₂ , hereinafter referred to as “silica”). Silica easily precipitates as the water temperature rises, and when heated to around 90 degrees with a water heater, it combines with other metals (eg, copper, zinc, etc.) in tap water to form a scale. This scale is called, for example, a silicate scale.

  The scale in which the silica and the metal are combined may be similar to the scale in which calcium or the like is precipitated alone in some cases. In the case of silica, when a divalent metal is present, a scale having silica as a causative component is likely to be formed, and adhesion to the piping is likely to occur. Moreover, the strength of the adhesive force to the piping varies depending on the type of metal ion.

  This invention is made | formed in view of the said situation, and it aims at removing the silica at the time of piping water containing the silica containing piping, and preventing adhesion of the scale to a warm water generator etc.

  The inventor of the present invention paid attention to the fact that the scale in which silica and other metals are combined may greatly vary depending on the metal and the adhesion to the pipes and heat exchanger. Based on this, for example, the scale is attached to the water supply pipe that supplies tap water to the hot water generator, and the scale that does not adhere to the water supply pipe is not attached to the hot water generator and is allowed to pass through. The present invention has been completed.

The hot water generator according to the present invention includes a hot water generator for heating hot tap water to generate hot water, a water supply pipe connected to the hot water generator for supplying tap water containing silica, and hot water as described in claim 1 A drain pipe connected to the generator for discharging hot water, and a scale which is disposed on at least a part of the water supply pipe and contains divalent metal or is plated with divalent metal and is a reaction product of silica and divalent metal. It is provided with a scale removing (adhesion) piping portion that easily adheres. That is, as the material for the scale removal piping part, a material that easily reacts with silica and that easily adheres to the scale as a reactant is selected to prevent the scale from flowing into the hot water generator.

According to the hot water generator according to the present invention , the scale in which the silica and the divalent metal have reacted is attached to the water supply pipe for supplying tap water before flowing into the hot water generator, so that the scale is attached to the hot water generator. Can be prevented.

According to the hot water generating device of the second aspect , even when the cross-sectional area of the water circulation portion of the water refrigerant heat exchanger is small, it is possible to prevent the scale from adhering to the inner surface and clogging due to the adhesion. According to the hot water generator of claim 3 , the use of relatively inexpensive copper can reliably prevent the scale from adhering to the hot water generator. According to the warm water generating apparatus of claim 4, the silica can be removed by readily available zinc or the like, and a scale that easily adheres can be formed. According to the hot water generator of claim 5 , even if the pipe part between the scale removing pipe part and the hot water generator is thin, clogging is unlikely to occur in this pipe.

(I) Silica removal method
The method for removing silica is roughly divided into a first stage in which a divalent metal to be reacted with silica is dissolved and a second stage in which the silica is reacted with the divalent metal and trapped as a scale. . In the first stage, in order to capture water and silica, a divalent metal is dissolved into metal ions. In the second stage, silica combines with a divalent metal to form a silicate scale, which tends to adhere to part of the piping as a scale. A part of the piping can be tube-shaped, ring-shaped, grain-shaped or rod-shaped (described later). In either the first stage or the second stage, the silica or scale is removed, for example, before supplying tap water to the hot water generator, i.e. in the water supply line.

  As a phenomenon in which the scale caused by silica adheres to a pipe containing a divalent metal, a phenomenon in which silica is dissolved by a divalent metal, the divalent metal dissolves in tap water supplied with water and reacts with silica. Phenomenon that makes it easy to capture and generate scale as a reaction product, or divalent metal on the inner peripheral surface of the water supply pipe reacts with silica to generate a scale as a reaction product, and directly on the inner peripheral surface of the water supply pipe It is thought that the phenomenon of capturing the scale is acting.

  A pipe such as a water supply pipe is made of a divalent metal or contains a divalent metal as a main component. Specific examples include zinc, iron, tin, lead, magnesium, and aluminum. The reason why the divalent metal is suitable for the removal of silica is considered to be that silica easily generates silicate scales with these metal ions. Further, in relation to the zeta potential, it is considered that the silica is charged with negative ions and the pipe is charged with positive ions.

  A part of the pipe may be formed of a divalent metal, or a part of the pipe made of another material (for example, steel) may be plated with a divalent metal. Further, zinc, iron, tin, lead, magnesium or aluminum may be used alone, or may be used as a compound part of two or more metals.

  As described above in part, the scale is a compound of silica and one or more divalent metals of zinc, iron, tin and the like. The water supply pipe and the hot water generator will be described later.

(B) Scale adhesion prevention method
As a method for preventing the adhesion of scale, a combination of a divalent metal and a material for the hot water generator is selected so that the scale in which the silica and the divalent metal have reacted hardly adheres to the hot water generator.

 The typical material of the hot water generator is copper, and the reason why the scale is difficult to adhere to copper is that the scale is precipitated and formed at the relevant site due to the material of the water supply pipe before the hot water generator. It is done.

(C) Hot water generator The hot water generator of the present invention includes a hot water generator, a water supply pipe and a drain pipe, and a scale removing pipe. Divalent metals, scales, etc. have been described above. The hot water generator includes a device that generates hot water by heat exchange, such as a water-refrigerant heat exchanger, and a device that generates hot water without heat exchange, such as a burner. In the former, the scale adheres to the water circulation part of the piping and the heat exchanger, and in the latter, the water circulation part does not exist, but the scale adheres to the water supply pipe.

  The water supply pipe is connected to, for example, a water circulation part of a water refrigerant heat exchanger and supplies tap water containing silica. A scale removing tube portion made of a divalent metal or a scale removing tube portion plated with a divalent metal at least partially may be included.

  In addition, as a scale removal piping part, it consists of a bivalent metal as shown to Fig.6 (a), and the scale removal piping part 60 of the joint shape which is easy to connect with upstream and downstream piping, FIG.6 (b) ), A ring-shaped scale removing pipe portion 62 made of a divalent metal as shown in FIG. 6 and installed in the pipe, a granule 64 made of a divalent metal as shown in FIG. The member 65 is combined with the scale removing pipe portion 66 installed in the pipe, or the pipe member 67 as a pipe as shown in FIG. You may employ | adopt the scale removal piping part 69 which combined the rod member 68 inserted in the radial direction inward.

  This scale removal pipe part can be provided with a water supply pipe in the middle part, the upstream side can be a resin pipe (resin pipe part), and the downstream side can be a copper pipe (copper pipe part).

  The drainage pipe is connected to, for example, a water circulation part of a water-refrigerant heat exchanger, and discharges heated hot water from the hot water generator and supplies it to a hot water storage tank or the like.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Example>
(Constitution)
FIG. 1 shows an embodiment in which the present invention is applied to a heat pump type water heater. This water heater includes a refrigerant circulation circuit 10 and a water circulation circuit 40. The refrigerant circulation circuit 10 collects a compressor 11 that compresses gas refrigerant, a water refrigerant heat exchanger (hot water generator) 13 that heats and exchanges heat between water and the refrigerant, an expansion valve 35, atmospheric heat, and the like. The heating evaporator 37 is connected in sequence. On the other hand, the water distribution circuit 40 is formed by sequentially connecting a hot water storage tank 42 for storing hot water (hot water), a water pump 43 for circulating water, and the water refrigerant heat exchanger 13.

  2 and 3 show details of the water-refrigerant heat exchanger 13, the water supply pipe 20, and the drain pipe 31. FIG. The water circulation part 17 of the water-refrigerant heat exchanger 13 is formed by joining two copper plates 15a and 15b each having a number of depressions. A slit fin 19 made of a copper plate is arranged in a water circulation part 17 formed by a pair of recesses. The water supply pipe 20 connected to the water flow passage 17 includes a relatively thin resin pipe 22 on the upstream side, a relatively thin copper pipe 23 on the downstream side, and a relatively thick galvanized steel pipe 25 in the middle.

  The galvanized steel pipe 25 as the scale removing pipe portion is provided so as to occupy only a part of the water supply pipe 20. It has an upper end connected to the resin tube 22 and a lower end connected to the copper tube 23, and connects the resin tube 22 and the copper tube 23. In this embodiment, the galvanized steel pipe 25 is composed of a straight pipe, and is provided so as to occupy a part of the water supply pipe 20 where tap water flows downward from above in the direction of gravity. The galvanized steel pipe 25 and the copper pipe 23 can have a configuration in which they are electrically conducted or a configuration in which they are electrically insulated. Moreover, the structure which installs one or both of the galvanized steel pipe 25 and the copper pipe 23 can also take the structure which is not installed.

  A drainage pipe 31 made of copper is connected to the water circulation part 17. A plurality of refrigerant flow tubes 33 are attached to the lower surface of the lower copper plate 15b.

(Function)
a. 1 When heating tap water with the heat pump type water heater of the embodiment, in FIG. 1, the evaporator 37 of the refrigerant circulation circuit 10 collects atmospheric heat or the like with a blower fan or the like, and the refrigerant flowing inside the tube 33 is evaporated into an evaporating gas. Turn into. The gasified refrigerant is sucked into the compressor 11 and mechanically compressed, and flows into the water refrigerant heat exchanger 13 as a high-temperature and high-pressure refrigerant.

  On the other hand, the tap water in the lower part of the hot water storage tank 42 of the water circulation circuit 40 flows into the water circulation part 17 of the water refrigerant heat exchanger 13 by the circulation water pump 43 and is heated by the high-temperature and high-pressure refrigerant of the evaporator 37. Then, the hot water flows into the upper part of the hot water storage tank 42. The refrigerant radiated by the water refrigerant heat exchanger 13 of the refrigerant circulation circuit 10 is decompressed by the expansion valve 35, flows into the evaporator 37, absorbs heat from atmospheric heat, etc., and is supplied to the compressor 11.

b. Water refrigerant heat exchanger When the tap water supplied from the water supply pipe 20 passes through the galvanized steel pipe 25, the silica in the water reacts with the zinc plated on the inner surface of the galvanized steel pipe 25, thereby increasing the amount of silica in the tap water. The portion becomes the scale 50 and adheres to the inner peripheral surface of the galvanized steel pipe 25.

  In addition, the scale 50 which did not adhere to the inner peripheral surface flows into the water circulation part 17 of the water refrigerant heat exchanger 13 from the water supply pipe 20. Here, the inner surface of the water circulation portion 17 is composed of an upper copper plate 15 a and a lower copper plate 15 b, and the scale 50 hardly adheres to these copper plates, is discharged from the drain pipe 31 together with hot water, and flows into the hot water storage tank 42.

(effect)
According to this embodiment, most of the scale 50, which is a reaction product of silica and zinc, adheres to the inner peripheral surface of the galvanized steel pipe 25 of the water supply pipe 20. Here, since the galvanized steel pipe 25 has a large inner diameter, even if the scale 50 is attached, the reduction in the cross-sectional area of the hollow hole is slight. The scale 50 hardly flows into the water-refrigerant heat exchanger 13, and adhesion to the slit fins 19 in the water passage portion 17 having a small cross-sectional area and clogging of the water passage portion 17 due to adhesion can be prevented. In this way, hot water having a predetermined temperature is efficiently generated from the tap water by the water refrigerant heat exchanger 13.

  Moreover, although the copper pipe 23 with a small inner diameter of the hollow hole is arranged on the downstream side of the galvanized steel pipe 25 of the water supply pipe 20, the scale 50 is not easily attached to the inner peripheral surface thereof, so that clogging does not become a problem. The inner diameter of the copper pipe 23 is relatively smaller than the inner diameter of the galvanized steel pipe. The inner diameter of the copper pipe 23 is reduced because the flow rate of tap water is relatively low in the galvanized steel pipe 25 and relatively high in the copper pipe 23, so that the scale in the copper pipe 23 is reduced. This is to relatively suppress precipitation.

<Test>
(A) Test apparatus In order to confirm the effect of the said Example, the test apparatus was prepared and the galvanized steel pipe 25 was installed between the resin pipe 22 and the copper pipe 23 in the water supply piping 20. FIG. The material of the galvanized steel pipe 25 is SPGW-15, and the dimensions are an outer diameter of 21.7 mm, a wall thickness of 2.8 mm, and a length of 300 mm. The location of the galvanized steel pipe 25 is about 1300 mm upstream from the inlet of the water-refrigerant heat exchanger 13. When tap water containing silica was continuously passed through the test apparatus at a flow rate of 0.8 L / min, the following results were obtained after 12 months.

(B) Results FIG. 4 shows the water flow resistance of the water supply pipe 20, the water refrigerant heat exchanger 13 and the drain pipe 31. The water flow resistance when the galvanized steel pipe 25 is not installed is 30 KPa, whereas the water flow resistance when the galvanized steel pipe 25 is installed is 15 KPa, which is halved compared to the case where the galvanized steel pipe 25 is not installed. .

  FIG. 5 shows the thickness of the scale deposited on the slit fins 19 in the water circulation part 17 in the water refrigerant heat exchanger 13. As can be seen, the deposition thickness when the galvanized steel pipe 25 is not installed is 0.05 to 0.1 mm, whereas the deposition thickness when the galvanized steel pipe 25 is installed is 0 to 0.01 mm. Yes, one digit smaller. In addition, the adhesion of the silica to the slit fin 19 was less when the galvanized steel pipe 25 was installed than when it was not installed.

(C) Suppression of scale adhesion As is clear from the test results, when a galvanized steel pipe 25 is installed in the middle of the water supply pipe 20 of the water refrigerant heat exchanger 13, the water supply pipe 20, the water refrigerant heat exchanger 13 and the drain pipe The water flow resistance of 31 is reduced, and the adhesion of silica and scale 50 to the slit fins 19 of the water passage portion 17 of the water refrigerant heat exchanger 13 is reduced.

  The reasons are not all obvious, but are estimated as follows. There is a close relationship between the decrease in the water flow resistance and the decrease in the amount of adhesion of the scale 50 to the slit fins 19 and the like. The reason why the amount of adhesion decreased is that the zinc plated on the inner peripheral surface of the galvanized steel pipe 25 first dissolved the silica contained in the tap water. Thereby, the silica in tap water is removed.

  Next, the zinc on the inner peripheral surface of the galvanized steel pipe 25 and silica in tap water reacted to form a scale 50. The scale 50 is easily attached to the inner peripheral surface of the galvanized steel pipe 25, and silica in tap water is removed by the adhesion of the scale 50. Furthermore, even if a scale that does not adhere to the inner peripheral surface of the galvanized steel pipe 25 enters the water-refrigerant heat exchanger 13, it does not easily adhere to the water passage portion 17 and the slit fin 19 made of copper, and the water-refrigerant heat together with hot water. Drained from the exchanger 13.

It is a whole explanatory view showing an example of the present invention. It is a perspective view which shows the water refrigerant | coolant heat exchanger and piping of the said Example. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. It is a graph which shows the water flow resistance value in the test which confirms an effect. It is a graph which shows the deposition thickness of the scale to the slit fin in the said test. (A) (b) (c) And (d) is a perspective view which shows the various aspects of a scale removal piping part.

Explanation of symbols

10: Refrigerant circulation circuit 13: Water refrigerant heat exchanger 17: Water circulation part 20: Water supply pipe 23: Copper pipe 25: Galvanized steel pipe 31: Drainage wiring 37: Evaporator 40: Water circulation circuit 42: Hot water storage tank 50: Scale

Claims (5)

A hot water generator (13) for generating hot water by heating tap water;
  A water supply pipe (20) connected to the hot water generator for supplying tap water containing silica, and a drain pipe (31) connected to the hot water generator for draining hot water;
  For scale removal, which is disposed on at least a part of the water supply pipe and contains a divalent metal or is plated with a divalent metal, and the scale (50), which is a reaction product of the silica and the divalent metal, easily adheres. A hot water generator comprising a pipe part (25). The hot water generator (13) has a water circulation part (17) through which tap water circulates and a refrigerant circulation part (33) through which a refrigerant circulates, and heat exchange is performed between the tap water and the refrigerant. The hot water generator according to claim 1, which is a water refrigerant heat exchanger to be generated. The hot water generator according to claim 2, wherein the water circulation part is made of a copper plate or a copper-plated metal plate. The hot water generating device according to claim 1, wherein the divalent metal of the scale removing pipe part is zinc, iron, tin, lead or magnesium. The hot water generator according to claim 1, wherein a copper pipe or a copper plated pipe part (23) is disposed between the scale removing pipe and the hot water generator.

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