JP7156510B2 - Polyurethane foam insulation and storage water heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a foamed polyurethane heat insulating material and a hot water storage type hot water heater.

2. Description of the Related Art A hot water storage type water heater using foamed polyurethane as a heat insulating material for a hot water storage tank is known. Patent Document 1 discloses a hot water storage type hot water heater in which a space between a hot water storage tank and an outer case is filled with foamed polyurethane.

Japanese Patent Application Laid-Open No. 58-160758

With the technique of Patent Literature 1, the polyurethane foam heat insulating material may be damaged during long-term use.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-described problems, and is a foamed polyurethane heat insulating material that is advantageous in improving durability when used in a hot water storage type hot water heater, and the foamed polyurethane heat insulating material. To provide a hot water storage type water heater equipped with a material.

The foamed polyurethane heat insulating material of the present invention is a foamed polyurethane heat insulating material that covers the hot water storage tank of a hot water storage type water heater, and the foamed polyurethane heat insulating material is a raw material inlet portion that is a portion that serves as an inlet for the urethane undiluted solution to the mold space. a single foamed polyurethane thermal insulation material comprising a low-density portion formed from a urethane concentrate and at least one high-density portion formed from a urethane solution and having a higher density than the low-density portion; One high-density portion includes a support portion that supports the components of the storage-type water heater, and the low-density portion is located farther from the raw material inlet than the support portion .
Further, the foamed polyurethane heat insulating material of the present invention is a foamed polyurethane heat insulating material that covers the hot water storage tank of a hot water storage type water heater, and the foamed polyurethane heat insulating material is a raw material that is the inlet of the urethane undiluted solution to the mold space. A unitary foamed polyurethane insulation having an inlet section comprising a low density section formed from a urethane concentrate and at least one high density section formed from a urethane liquid and having a higher density than the low density section. , at least one high-density portion includes an inner wall portion having an inner surface that contacts the surface of the hot water storage tank, and an outer wall portion having an outer surface opposite to the inner surface corresponds to the low-density portion, and the outer wall portion includes: It is positioned farther from the raw material inlet than the inner wall .
A hot water storage type hot water heater of the present invention includes the foamed polyurethane heat insulating material and the hot water storage tank.

According to the present invention, there are provided a foamed polyurethane heat insulating material which is advantageous in improving durability when used in a hot water storage type hot water heater, and a hot water storage type hot water heater provided with the foamed polyurethane heat insulating material. becomes possible.

1 is a front view showing a hot water storage type hot water heater according to Embodiment 1. FIG. Fig. 2 is a longitudinal sectional view showing a hot water storage tank provided in the hot water storage type water heater shown in Fig. 1 and a heat insulating material covering the hot water storage tank; FIG. 2 is a cross-sectional plan view showing a hot water storage tank unit included in the hot water storage type water heater shown in FIG. 1 ;

Embodiments will be described below with reference to the drawings. Elements that are common or correspond to each figure are denoted by the same reference numerals, and overlapping descriptions are simplified or omitted.

Embodiment 1.
FIG. 1 is a front view showing hot water storage type water heater 50 according to Embodiment 1. FIG. As shown in FIG. 1 , the hot water storage type hot water heater 50 of Embodiment 1 has a heat pump unit 1 and a hot water storage tank unit 40 . The hot water storage tank unit 40 has a hot water storage tank 10 having a cylindrical outer shape and an outer shell case 30 having a substantially rectangular parallelepiped shape. The hot water storage tank 10 is housed in the outer case 30 while being covered with a heat insulating material, which will be described later. The heat pump unit 1 functions as heating means for heating water to generate hot water. The hot water stored in the hot water storage tank 10 is supplied to a predetermined hot water supply destination as needed. Note that the heating means in the present disclosure is not limited to the heat pump type, and may be of any configuration such as a configuration in which a heater is installed in the hot water storage tank 10, for example.

A mixing valve 15 for adjusting the hot water supply temperature is provided inside the outer shell case 30 . The water supply pipe 11 supplies water from a water source such as tap water. The downstream portion of the water supply pipe 11 branches within the outer shell case 30 and is connected to the lower portion of the hot water storage tank 10 and the mixing valve 15 respectively. A heat pump outgoing pipe 13 a for sending low-temperature water in the hot water tank 10 to the heat pump unit 1 is further connected to the lower portion of the hot water tank 10 . A heat pump return pipe 13 b is connected to the upper portion of the hot water storage tank 10 for returning hot water heated by the heat pump unit 1 to the inside of the hot water storage tank 10 . The hot water supply pipe 12 is a pipe for supplying hot water to a predetermined hot water tap (not shown) such as a shower in a bathroom or a faucet in a kitchen. The bath pipe 14 is a pipe for supplying hot water to a bathtub (not shown).

The upper surface of the outer case 30 of the hot water storage tank unit 40 is composed of a top plate 32 . A riser 31 is formed in the lower part of the outer shell case 30, the front side of which is recessed. The riser portion 31 is provided for drawing each of the above-described water supply pipe 11, heat pump outgoing pipe 13a, heat pump return pipe 13b, hot water supply pipe 12, and bath outgoing pipe 14 into the hot water storage tank unit 40, or from inside the hot water storage tank unit 40. Each is provided with a pipe connection for withdrawal.

A support leg 35 is connected to the lower portion of the outer case 30 . For example, the hot water storage tank unit 40 is installed on the base 90 by fixing each support leg 35 to the base 90 made of concrete with anchor bolts (not shown). A pipe cover (not shown) is provided below the outer case 30 in order to cover the pipe connection portion and each pipe connected to the pipe connection portion to improve the design of the hot water storage tank unit 40. be provided.

When the hot water storage type hot water heater 50 is used, it is as follows. In the hot water storage tank 10, the upper side becomes high temperature hot water and the lower side becomes low temperature water. The high-temperature water in the upper layer and the low-temperature water in the lower layer are maintained without being mixed due to the difference in specific gravity. By the water supply from the water supply pipe 11, the inside of the hot water storage tank 10 is always kept full of high-temperature hot water in the upper layer and low-temperature water in the lower layer. In addition, water pressure from the water supply pipe 11 always acts on the inside of the hot water storage tank 10 .

During the heat storage operation in which the hot water heated by the heat pump unit 1 is stored in the hot water storage tank 10, the operation is as follows. Low-temperature water in the lower part of the hot water storage tank 10 is sent to the water-refrigerant heat exchanger in the heat pump unit 1 through the heat pump outgoing pipe 13a. After being heated by the water-refrigerant heat exchanger, the high-temperature hot water passes through the heat pump return pipe 13b and flows into the hot water storage tank 10 from the top of the hot water storage tank 10 .

A tank upper pipe 16 connects the upper part of the hot water storage tank 10 and the mixing valve 15 . During hot water supply, high-temperature hot water in the hot water storage tank 10 flows into the mixing valve 15 through the tank upper pipe 16 due to the water pressure from the water supply pipe 11 . The mixing valve 15 adjusts the mixing ratio of hot water from the tank upper pipe 16 and low-temperature water from the water supply pipe 11 to generate hot water at a temperature set by the user with a remote control (not shown) or the like. . The hot water mixed by the mixing valve 15 is supplied to the hot water tap or the bathtub through the hot water supply pipe 12 or the bath pipe 14 .

Inside the outer shell case 30, devices other than the devices described above, such as pipes, valves, pumps, heat exchangers, sensors, and control devices, may be further provided. Detailed description is omitted.

FIG. 2 is a longitudinal sectional view showing the hot water storage tank 10 provided in the hot water storage type water heater 50 shown in FIG. FIG. 3 is a cross-sectional plan view showing hot water tank unit 40 included in hot water storage type hot water heater 50 shown in FIG. The central axis of the hot water storage tank 10 is hereinafter referred to as the "tank central axis". The hot water storage type water heater 50 is installed in a posture in which the central axis of the tank is substantially parallel to the vertical line. In the following description, the positional relationship is specified based on the attitude of storage-type water heater 50 during use.

FIG. 3 corresponds to a cross-sectional view taken along a plane perpendicular to the central axis of the tank. The lower side in FIG. 3 corresponds to the front surface of the hot water storage tank unit 40, and the upper side in FIG. FIG. 2 is a cross-sectional view taken along a plane including the central axis of the tank, and corresponds to a cross-sectional view taken along line II--II in FIG. In FIG. 3, illustration of devices other than the hot water storage tank 10, the heat insulating material, and the outer shell case 30 is omitted.

The hot water storage tank 10 is made of, for example, a metal material such as stainless steel. As shown in FIG. 2, the hot water storage tank 10 has a cylindrical tank body 10a, an upper end plate 10b closing an upper opening of the tank body 10a, and a lower end plate 10c closing a lower opening of the tank body 10a. . The upper end plate 10b has a hemispherical shape or an upside down bowl shape. The lower end plate 10c has a hemispherical or bowl-like shape.

Hot water storage type water heater 50 of the present embodiment includes upper heat insulator 60 , front heat insulator 61 , rear heat insulator 62 , and lower heat insulator 63 as heat insulators covering hot water tank 10 . Each of these insulations corresponds to foamed polyurethane insulation. The polyurethane foam heat insulating material is formed by molding polyurethane foam using a mold (not shown). The foamed polyurethane insulation may correspond to rigid urethane foam.

The upper heat insulating material 60 at least partially covers the surface of the upper end plate 10b. The front heat insulating material 61 and the rear heat insulating material 62 at least partially cover the surface of the tank body 10a. In the illustrated example, the front heat insulating material 61 covers a half area corresponding to the front side of the surface of the tank body 10a. The rear surface heat insulating material 62 covers half of the surface of the tank body 10a, which corresponds to the rear surface side. The lower heat insulating material 63 at least partially covers the surface of the lower end plate 10c.

Polyurethane foam insulation has a structure in which gas with low thermal conductivity is confined in individual fine cells, and has excellent heat insulation performance. A foamed polyurethane heat insulating material is made by, for example, mixing two undiluted liquids containing polyol and polyisocyanate as main components in a foaming machine, injecting the liquid urethane liquid into a mold, and foaming and curing it.

There are two types of injection methods for undiluted urethane: the closed injection method, in which the undiluted urethane solution is injected through a specific injection port after the mold is closed, and the open injection method, in which the undiluted urethane solution is injected while the mold is open. In the following description, a polyurethane foam insulation made by a closed injection method will be mainly described as an example.

A foamed polyurethane insulation according to the present disclosure has a low density portion and at least one high density portion. The high density section has a higher density than the low density section. In this disclosure, density for foamed polyurethane insulation shall mean apparent density. The apparent density is a density calculated by taking the sum of the volume occupied by the substance itself and the volume of internal voids as a volume for density calculation.

The high density section has a higher thermal insulation than the low density section. That is, the thermal conductivity of the high density portion is lower than that of the low density portion. Also, the high density portion has higher mechanical strength than the low density portion. Mechanical strength is the ability of a material to resist deformation or breakage. Mechanical strength can be represented, for example, by at least one of tensile strength, compressive strength and shear strength.

A space having a shape corresponding to the shape of the foamed polyurethane heat insulating material (hereinafter referred to as “mold space”) is formed inside the mold. In the following description, the portion that serves as an inlet for the urethane undiluted solution into the mold space during molding of the foamed polyurethane heat insulating material is referred to as a "raw material inlet". When a foamed polyurethane heat insulating material is produced by the closed injection method, there is a tendency that the density is low in the region far from the raw material inlet, and the density is high in the region close to the raw material inlet. By utilizing this fact, it is possible to control the region in which the high-density portion is formed and the region in which the low-density portion is formed in the foamed polyurethane heat insulating material. A plurality of thick and short arrows in FIGS. 2 and 3 indicate the positions of raw material inlets of the polyurethane foam heat insulating materials.

The front heat insulating material 61 has a support portion 61 a that supports components (not shown) of the hot water storage type hot water heater 50 . The components may be, for example, at least one of piping, valves, pumps, heat exchangers, sensors, controllers. The component may be fixed to the support 61a using, for example, at least one of screws, adhesive tape, snap fit, and concave-convex fit. The support portion 61a supports at least part of the weight of the component. In the illustrated example, the support portion 61a protrudes outward from the outer peripheral surface 61b, which is the surface of the front heat insulating material 61. As shown in FIG.

As shown in FIG. 2, the front heat insulator 61 has a low density portion 61c. The support portion 61a corresponds to a high density portion having a higher density than the low density portion 61c. The weight of the components acts on the supporting portion 61a. Therefore, if the mechanical strength of the support portion 61a is low, the support portion 61a may be deformed during long-term use, making it impossible to hold the components in proper positions. In contrast, in the present embodiment, the support portion 61a corresponds to the high-density portion, which is advantageous in increasing the mechanical strength of the support portion 61a. Therefore, deformation of the support portion 61a can be reliably prevented during long-term use, which is advantageous in improving the durability of the front heat insulating material 61 including the support portion 61a.

The front heat insulating material 61 has a raw material inlet portion 61d. The support portion 61a is located near the raw material inlet portion 61d. The low-density portion 61c is located farther from the raw material inlet portion 61d than the support portion 61a. In the illustrated example, the raw material inlet portion 61d corresponds to part of the support portion 61a. This is advantageous in increasing the density of the support portions 61a, and is thus advantageous in improving the mechanical strength of the support portions 61a. In the illustrated example, the support portion 61a and the raw material inlet portion 61d are positioned higher than the low density portion 61c with respect to the vertical position.

The upper heat insulating material 60 has an inner wall portion 60a and an outer wall portion 60b. The inner wall portion 60a has an inner surface 60c in contact with the surface of the upper end plate 10b. In the illustrated example, the inner surface 60c is a concave curved surface having a shape corresponding to the convex curved surface of the upper end plate 10b. The outer wall portion 60b has an outer surface 60d facing away from the inner surface 60c. The outer wall portion 60b is located outside the inner wall portion 60a. The outer wall portion 60b does not contact the surface of the hot water storage tank 10 . The outer wall portion 60b is located farther from the surface of the hot water storage tank 10 than the inner wall portion 60a.

The outer wall portion 60b corresponds to the low density portion. The inner wall portion 60a corresponds to a high density portion having a higher density than the outer wall portion 60b. Since the inner wall portion 60a is in contact with the surface of the hot water storage tank 10 which becomes hot, it is exposed to a higher temperature than the outer wall portion 60b. As a result, the inner wall portion 60a is more susceptible to thermal deterioration than the outer wall portion 60b. Therefore, if the mechanical strength of the inner wall portion 60a is low, the walls of the cells of the inner wall portion 60a will break during long-term use, making it impossible to confine the gas in the cells, and the heat insulation performance of the inner wall portion 60a will be reduced. there is a possibility. In contrast, in the present embodiment, the inner wall portion 60a corresponds to the high-density portion, which is advantageous in increasing the mechanical strength of the inner wall portion 60a. Therefore, it is possible to reliably prevent the inner wall portion 60a from being damaged during long-term use, which is advantageous in improving the durability of the upper heat insulating material 60 including the inner wall portion 60a.

The upper heat insulating material 60 has a raw material inlet portion 60e. The inner wall portion 60a is located near the raw material inlet portion 60e. The outer wall portion 60b is located farther from the raw material inlet portion 60e than the inner wall portion 60a. In the illustrated example, the raw material inlet portion 60e corresponds to a portion of the inner wall portion 60a. This is advantageous in increasing the density of the inner wall portion 60a, and thus is more advantageous in improving the mechanical strength of the inner wall portion 60a.

The lower heat insulating material 63 has an inner wall portion 63a and an outer wall portion 63b. The inner wall portion 63a has an inner surface 63c in contact with the surface of the lower end plate 10c. In the illustrated example, the inner surface 63c is a concave curved surface having a shape corresponding to the convex curved surface of the lower end plate 10c. The outer wall portion 63b has an outer surface 63d that faces the opposite side of the inner surface 63c. The outer wall portion 63b is located outside the inner wall portion 63a. The outer wall portion 63 b does not contact the surface of the hot water storage tank 10 . The outer wall portion 63b is located farther from the surface of the hot water storage tank 10 than the inner wall portion 63a.

The outer wall portion 63b corresponds to the low density portion. The inner wall portion 63a corresponds to a high density portion having a higher density than the outer wall portion 63b. When the hot water storage tank 10 is filled with hot water, the surface of the lower end plate 10c also becomes hot. At this time, since the inner wall portion 63a is in contact with the surface of the lower end plate 10c which has reached a high temperature, it is exposed to a higher temperature than the outer wall portion 63b. As a result, the inner wall portion 63a is more susceptible to thermal deterioration than the outer wall portion 63b. Therefore, if the mechanical strength of the inner wall portion 63a is low, the walls of the cells of the inner wall portion 63a will break during long-term use, making it impossible to confine the gas in the cells, and the heat insulation performance of the inner wall portion 63a will be reduced. there is a possibility. In contrast, in the present embodiment, the inner wall portion 63a corresponds to the high-density portion, which is advantageous in increasing the mechanical strength of the inner wall portion 63a. Therefore, it is possible to reliably prevent the inner wall portion 63a from being damaged during long-term use, which is advantageous in improving the durability of the lower heat insulating material 63 including the inner wall portion 63a.

The lower heat insulating material 63 has a raw material inlet portion 63e. The inner wall portion 63a is located near the raw material inlet portion 63e. The outer wall portion 63b is located farther from the raw material inlet portion 63e than the inner wall portion 63a. In the illustrated example, the raw material inlet portion 63e corresponds to a portion of the inner wall portion 63a. This is advantageous in increasing the density of the inner wall portion 63a, which is more advantageous in improving the mechanical strength of the inner wall portion 63a.

The rear heat insulating material 62 has a fitting portion 62a that fits with the upper heat insulating material 60, which is another heat insulating material, and a low density portion 62b. The fitting portion 62a corresponds to a high density portion having a higher density than the low density portion 62b. If the mechanical strength of the fitting portion 62a is low, there is a possibility that the fitting portion 62a will be deformed during long-term use, creating a gap with the upper heat insulating material 60 . A gap is not preferable because it leads to heat leakage. In contrast, in the present embodiment, the fitting portion 62a corresponds to the high-density portion, which is advantageous in increasing the mechanical strength of the fitting portion 62a. Therefore, it is possible to reliably prevent deformation of the fitting portion 62a during long-term use. Therefore, it is possible to reliably prevent the formation of a gap with respect to the upper heat insulating material 60, so that heat leakage can be reliably prevented.

The rear heat insulating material 62 has a raw material inlet portion 62c. The fitting portion 62a is positioned close to the raw material inlet portion 62c. The low-density portion 62b is located farther from the raw material inlet portion 62c than the fitting portion 62a. In the illustrated example, the fitting portion 62a and the raw material inlet portion 62c are positioned higher than the low density portion 62b with respect to the vertical position.

The front heat insulating material 61 has a fitting portion 61e that fits with the upper heat insulating material 60, which is another heat insulating material, and a low density portion 61f. The fitting portion 61e corresponds to a high density portion having a higher density than the low density portion 61f. If the mechanical strength of the fitting portion 61e is low, there is a possibility that the fitting portion 61e will be deformed during long-term use, and a gap will be generated between the fitting portion 61e and the upper heat insulating material 60 . A gap is not preferable because it leads to heat leakage. In contrast, in the present embodiment, the fitting portion 61e corresponds to the high-density portion, which is advantageous in increasing the mechanical strength of the fitting portion 61e. Therefore, it is possible to reliably prevent deformation of the fitting portion 61e during long-term use. Therefore, it is possible to reliably prevent the formation of a gap with respect to the upper heat insulating material 60, so that heat leakage can be reliably prevented.

The front heat insulator 61 has a raw material inlet 61g. The fitting portion 61e is located near the raw material inlet portion 61g. The low-density portion 61f is located farther from the raw material inlet portion 61g than the fitting portion 61e. In the illustrated example, the positions in the vertical direction are as follows. The fitting portion 61e and the raw material inlet portion 61g are positioned higher than the low density portion 61f. The low-density portion 61f is positioned higher than the support portion 61a and the raw material inlet portion 61d.

In the illustrated example, each of the fitting portion 61e and the fitting portion 62a protrudes upward. Each of the fitting portion 61e and the fitting portion 62a has an arc shape along the circumferential direction of the tank body 10a at a position away from the surface of the tank body 10a. An annular protrusion is formed by connecting both ends of the fitting portion 61e to both ends of the fitting portion 62a. The upper heat insulating material 60 has a fitting portion 60f. The fitting portion 60f is a protrusion that protrudes downward. The fitting portion 60f is annularly formed along the outer peripheral surface of the tank body portion 10a or the upper end plate 10b. The fitting portion 60f is fitted to the inner peripheral side of the annular protrusion formed by the fitting portion 61e and the fitting portion 62a.

The front heat insulating material 61 has support portions 61a and fitting portions 61e corresponding to a plurality of high-density portions provided at different positions. Thus, multiple dense sections may be provided at different locations within a single foamed polyurethane insulation. This is more advantageous in improving the durability of the foamed polyurethane heat insulating material.

The front heat insulating material 61 has a plurality of raw material inlet portions 61d and raw material inlet portions 61g which are located at different positions. That is, the mold for molding the front heat insulating material 61 is provided at a plurality of positions with inlets for the urethane undiluted solution into the mold space. In this manner, a plurality of inlets for the urethane undiluted solution may be provided for one mold space. By doing so, multiple high density sections can be provided at different locations within a single foamed polyurethane insulation.

The support portion 61a and the fitting portion 61e correspond to a high portion located higher than the low-density portion 61c in terms of vertical position. In addition, the fitting portion 62a corresponds to a high portion positioned higher than the low-density portion 62b with respect to the position in the vertical direction. According to the present embodiment, the following effects can be obtained by providing such a high portion. The temperature of the hot water in the hot water storage tank 10 increases with increasing position. Since the support portion 61a, the fitting portion 61e, and the fitting portion 62a, which correspond to the high-density portion with high heat insulating performance, are arranged at high positions, the heat insulating property of the high temperature region of the hot water storage tank 10 can be further improved. Since the temperature of the hot water in the hot water storage tank 10 is relatively low in the region where the low-density portion 61c and the low-density portion 62b are arranged, the heat insulation performance of the low-density portion 61c and the low-density portion 62b is sufficient.

The hot water storage type water heater 50 may include low-lying insulation having a higher thermal conductivity than foamed polyurethane insulation. For example, the lower heat insulating material 63 may be made of foamed polystyrene instead of foamed polyurethane. In this case, the lower heat insulating material 63 covers the hot water storage tank 10 at a position lower than the upper heat insulating material 60, the front heat insulating material 61, and the rear heat insulating material 62, which are polyurethane foam heat insulating materials, with respect to the vertical position. corresponds to Since the temperature of the hot water in the hot water storage tank 10 is relatively low in the region where the low-place heat insulating material is arranged, sufficient heat insulating performance can be obtained even with the low-place heat insulating material having a higher thermal conductivity than the polyurethane foam heat insulating material. . Cost can be reduced by using a low-place heat insulating material having a higher thermal conductivity than foamed polyurethane heat insulating material.

In the following description, the thickness dimension of the heat insulating material is the dimension along the radial direction of the hot water storage tank 10 . That is, the thickness dimension is the thickness of the insulation measured along a straight line perpendicular to the central axis of the tank. Further, the distance between the tank surface, which is the surface of the hot water storage tank 10, and the inner wall 30a of the outer shell case 30, measured along the normal line of the tank surface is referred to as the "opposing distance." It is difficult to increase the thickness of the heat insulating material in areas where the facing distance is small.

As shown in FIG. 3, the front heat insulating material 61 has a thin portion 61h, a thin portion 61i, and a low density portion 61j. The thin portion 61h is arranged at a position with a facing distance D2 that is smaller than the facing distance D1 at the position of the low-density portion 61j. The thin portion 61i is arranged at a position with a facing distance D3 that is smaller than the facing distance D1 at the position of the low-density portion 61j. The thickness dimension of each of the thin portions 61h and 61i is smaller than the thickness dimension of the low density portion 61j. Each of the thin portions 61h and 61i corresponds to a high density portion having a higher density than the low density portion 61j.

Since the thin portions 61h, 61i are smaller in thickness than the low-density portion 61j, if the mechanical strength of the thin portions 61h, 61i is low, the thin portions 61h, 61i may deform during long-term use. be. In contrast, in the present embodiment, the thin portions 61h and 61i correspond to the high density portions, which is advantageous in increasing the mechanical strength of the thin portions 61h and 61i. Therefore, deformation of the thin portions 61h and 61i can be reliably prevented during long-term use, which is advantageous in improving the durability of the thin portions 61h and 61i.

In addition, since the thin portions 61h and 61i are smaller in thickness than the low-density portion 61j, if the thin portions 61h and 61i have high thermal conductivity, it is difficult to improve the heat insulation performance of the thin portions 61h and 61i. . In contrast, in the present embodiment, the thin portions 61h and 61i correspond to the high density portions, which is advantageous in lowering the thermal conductivity of the thin portions 61h and 61i. Therefore, it is advantageous in improving the heat insulating performance of the thin portions 61h and 61i.

The front heat insulating material 61 has a raw material inlet portion 61k and a raw material inlet portion 61m. The thin portion 61h is located near the raw material inlet portion 61k. The thin portion 61i is located near the raw material inlet portion 61m. The low density portion 61j is located farther from both the raw material inlet portions 61k and 61m than the thin portions 61h and 61i.

The rear heat insulating material 62 has a thin portion 62d, a thin portion 62e, and a low density portion 62f. The thin portion 62d is arranged at a position with a facing distance D2 that is smaller than the facing distance D4 at the position of the low density portion 62f. The thin portion 62e is arranged at a position with a facing distance D3 that is smaller than the facing distance D4 at the position of the low density portion 62f. The thickness dimension of each of the thin portions 62d and 62e is smaller than the thickness dimension of the low density portion 62f. Each of the thin portions 62d and 62e corresponds to a high density portion having a higher density than the low density portion 62f.

Since the thin portions 62d and 62e are smaller in thickness than the low-density portion 62f, if the thin portions 62d and 62e have low mechanical strength, the thin portions 62d and 62e may deform during long-term use. be. In contrast, in the present embodiment, the thin portions 62d and 62e correspond to the high density portions, which is advantageous in increasing the mechanical strength of the thin portions 62d and 62e. Therefore, deformation of the thin portions 62d and 62e can be reliably prevented during long-term use, which is advantageous in improving the durability of the thin portions 62d and 62e.

In addition, since the thin portions 62d and 62e are smaller in thickness than the low-density portion 62f, if the thin portions 62d and 62e have high thermal conductivity, it is difficult to improve the heat insulation performance of the thin portions 62d and 62e. . In contrast, in the present embodiment, the thin portions 62d and 62e correspond to the high density portions, which is advantageous in reducing the thermal conductivity of the thin portions 62d and 62e. Therefore, it is advantageous in improving the heat insulation performance of the thin portions 62d and 62e.

The rear heat insulating material 62 has a raw material inlet portion 62g and a raw material inlet portion 62h. The thin portion 62d is located near the raw material inlet portion 62g. The thin portion 62e is located near the raw material inlet portion 62h. The low density portion 62f is located farther from both the raw material inlet portions 62g and 62h than the thin portions 62d and 62e.

While the foregoing has focused on foamed polyurethane insulation made by the closed injection method, the foamed polyurethane insulation according to the present disclosure may also be made by the open injection method. When adopting the open injection method, urethane is added while moving the injection port so that the amount of urethane to be injected in the part to be high density is larger than the amount of urethane to be injected in the part to be low density with the mold open. Inject stock solution. After that, the mold is closed and molded.

1 heat pump unit 10 hot water storage tank 10a tank body 10b upper end plate 10c lower end plate 11 water supply pipe 12 hot water supply pipe 13a heat pump outgoing pipe 13b heat pump return pipe 14 bath outgoing pipe 15 mixing valve 16 tank upper pipe 30 outer case 30a inner wall 31 riser 32 top plate 35 support leg 40 hot water storage tank unit 50 hot water heater 60 upper heat insulator 60a inner wall 60b outer wall 60c inner surface 60d outer surface 60e raw material entrance portion 60f fitting portion 61 front heat insulating material 61a support portion 61b outer peripheral surface 61c low density portion 61d raw material entrance portion 61e fitting portion 61f low density portion 61g raw material entrance portion , 61h, 61i thin portion, 61j low density portion, 61k, 61m raw material entrance portion, 62 rear heat insulating material, 62a fitting portion, 62b low density portion, 62c raw material entrance portion, 62d, 62e thin portion, 62f low density portion, 62g, 62h raw material inlet portion 63 lower heat insulating material 63a inner wall portion 63b outer wall portion 63c inner surface 63d outer surface 63e raw material inlet portion

Claims (9)

A foamed polyurethane heat insulating material covering a hot water storage tank of a hot water storage type water heater,
The foamed polyurethane heat insulating material has a raw material inlet portion that is a portion that serves as an inlet for the urethane undiluted solution to the mold space,
A single piece of foamed polyurethane insulation comprising:
a low-density portion formed from the urethane undiluted solution ;
at least one high-density portion formed from the urethane undiluted solution and having a higher density than the low-density portion;
with
The at least one high-density portion includes a support portion that supports components of the storage-type water heater,
The low-density portion is a foamed polyurethane heat insulating material located farther from the raw material inlet portion than the support portion . A foamed polyurethane heat insulating material covering a hot water storage tank of a hot water storage type water heater,
The foamed polyurethane heat insulating material has a raw material inlet portion that is a portion that serves as an inlet for the urethane undiluted solution to the mold space,
A single piece of foamed polyurethane insulation comprising:
a low-density portion formed from the urethane undiluted solution ;
at least one high-density portion formed from the urethane undiluted solution and having a higher density than the low-density portion;
with
The at least one high-density portion includes an inner wall portion having an inner surface in contact with the surface of the hot water storage tank,
An outer wall portion having an outer surface opposite to the inner surface corresponds to the low-density portion,
The outer wall portion is a foamed polyurethane heat insulating material located farther from the raw material inlet portion than the inner wall portion . The foaming according to claim 1 or claim 2, wherein the at least one high-density portion includes a high-place portion located higher than the low-density portion with respect to a vertical position when the storage-type hot water heater is in use. Polyurethane insulation. The dimension of the foamed polyurethane heat insulating material in the radial direction of the hot water storage tank is the thickness dimension,
The foamed polyurethane heat insulating material according to any one of claims 1 to 3, wherein said at least one high density portion includes a thin portion having said thickness dimension smaller than said thickness dimension of said low density portion. . 5. The polyurethane foam according to any one of claims 1 to 4, wherein the at least one high-density portion includes a plurality of high-density portions provided at different positions of the single polyurethane foam heat insulating material. Insulation. The foamed polyurethane heat insulating material according to any one of claims 1 to 5, wherein the at least one high density portion includes a fitting portion that fits against another heat insulating material. The foamed polyurethane heat insulating material according to any one of claims 1 to 6,
the hot water storage tank;
Storage hot water heater. A low-place heat insulating material covering the hot water storage tank at a position lower than the polyurethane foam heat insulating material with respect to the vertical position when the hot water storage type water heater is in use,
8. The hot water storage type water heater according to claim 7, wherein said low-place heat insulating material has a higher thermal conductivity than said foamed polyurethane heat insulating material. An outer case for storing the hot water storage tank and the foamed polyurethane heat insulating material,
The distance between the tank surface, which is the surface of the hot water storage tank, and the inner wall of the outer case, measured along the normal line of the tank surface, is the facing distance,
9. The storage-type water heater according to claim 7, wherein said at least one high-density portion includes a thin-walled portion disposed at said facing distance that is smaller than said facing distance at said low-density portion.

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