JP2013139888A - Storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a storage type water heater that can reliably prevent a part from being broken due to frozen water in a pipe in the water heater with no water remaining in a hot water storage tank.SOLUTION: A storage type water heater includes: a hot water storage tank; a water supply pipe 2b connected to the hot water storage tank and guiding water supplied from an external water source to the hot water storage tank; a decompression valve disposed in the middle of the water supply pipe 2b, and reducing the water pressure of the external water source; a check valve 15 provided upstream of the decompression valve and restricting a reverse flow; and a water drainage valve 17 provided in a flow path between the check valve 15 and the decompression valve, and configured to be closed when the water pressure of the external water source is applied, and to be opened when the water pressure is not applied, to thereby discharge the water in the flow path.

Description

  The present invention relates to a hot water storage type water heater.

  2. Description of the Related Art Hot water storage type water heaters that have a hot water storage tank that stores hot water boiled by heating means such as a heat pump are widely used. In general, since the main body of the hot water storage type hot water heater is installed outside the room, there is a possibility that the water in the pipe inside the hot water heater will freeze in winter.

  Patent Document 1 discloses a hot water supply device in which a hot water supply port having a drain plug, a water supply port, a bath connection port and a bath return connection port, and a heater for heating bath water are provided in an integrated case. Yes. In this hot water supply device, when there is a possibility that the water in the pipe may freeze, the water drainage tap is frozen due to the heat generated by the internal component parts for the water remaining in the drainage tap. It is supposed to be possible to prevent this.

Japanese Patent Laid-Open No. 7-120061

  Immediately after the installation is completed, the contractor who installs the water heater passes water through the water heater and checks for water leaks at the places where the pipes are constructed. After that, if the use of the water heater is not started immediately, the water in the hot water storage tank is drained and electricity is stopped. For this reason, when construction is performed in winter, water remaining in the piping may freeze and damage parts. In general, the water supply pipe connection port of a water heater to which an external water supply pipe that supplies water from a water source is connected so that the water in the water heater does not flow backward to the external water supply pipe and contaminate the water quality. A check valve is provided. In addition, a pressure reducing valve for reducing the water source water pressure to a constant pressure is installed in the middle of the water supply pipe in the water heater that guides the water supplied from the external water supply pipe to the hot water storage tank. In the water heater having such a configuration, it is particularly difficult to drain water from the flow path between the check valve and the pressure reducing valve, and when the water freezes, the pressure reducing valve and the water supply pipe connection port There is a possibility of damaging the parts.

  In the conventional water heater disclosed in Patent Document 1, the drain plug must be manually opened to drain the water in the pipe. Therefore, when the contractor does not perform the operation of opening the drain plug. It is impossible to prevent damage to parts due to freezing. Further, in this water heater, the internal component parts do not generate heat unless electricity is supplied, and it is not possible to prevent the water in the drain plug or the pipe from being frozen. For this reason, when electricity is stopped after construction, the antifreezing effect cannot be expected.

  The present invention has been made to solve the above-described problems, and reliably ensures that water in the piping inside the water heater freezes and damages parts when the water in the hot water storage tank is drained. It is an object of the present invention to provide a hot water storage type water heater that can be prevented.

  The hot water storage type hot water heater according to the present invention is provided in the middle of the hot water storage tank, the hot water tank connected to the hot water storage tank, and the water supply pipe for guiding the water supplied from the external water source to the hot water storage tank, and reduces the water pressure of the external water source. A pressure reducing valve that is provided upstream of the pressure reducing valve, and is provided in a flow path between the check valve and the pressure reducing valve, and when the water pressure of the external water source is applied. And a drain valve that opens and drains water in the flow path when the water pressure of the external water source is not applied.

  According to the present invention, when the water in the hot water storage tank is drained, the water in the flow path between the check valve and the pressure reducing valve can be automatically discharged. It is possible to reliably prevent water from freezing and damaging components in the water heater.

It is a block diagram which shows the hot water storage type water heater of Embodiment 1 of this invention. It is sectional drawing of the water supply piping connection port unit with which the hot water storage type water heater shown in FIG. 1 is provided.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a hot water storage type water heater according to Embodiment 1 of the present invention. As shown in FIG. 1, the hot water storage type water heater of this embodiment includes a hot water storage tank unit 100 in which a hot water storage tank 1 is mounted, and a heating means 50 that generates water by heating water by a heat pump cycle. The hot water storage tank unit 100 has an outer case 20 that houses the hot water storage tank 1 and other components. A water supply pipe connection port unit 4 is installed at the lower part of the outer case 20. The water supply pipe connection port unit 4 is connected to an external water supply pipe 3 for supplying water from an external water source such as water supply outside the outer case 20. On the external water supply pipe 3, a water supply stop cock 14 capable of stopping the supply of water is attached at the time of construction.

  The water supply pipe connection port unit 4 is connected to one end of the water supply pipe 2 b inside the outer case 20. The other end of the water supply pipe 2 b is connected to the pressure reducing valve 5. The pressure reducing valve 5 has a function of reducing the primary side water source water pressure and keeping the secondary side pressure constant. The water supply pipe 2 a on the downstream side of the pressure reducing valve 5 is branched into two, one connected to the lower part of the hot water storage tank 1 and the other connected to the mixing valve 11. The water supplied from the external water supply pipe 3 to the hot water storage tank unit 100 is supplied from the water supply pipe connection port unit 4 to the hot water storage tank 1 and the mixing valve 11 through the water supply pipe 2b, the pressure reducing valve 5, and the water supply pipe 2a. .

  The water stored in the hot water storage tank 1 is conveyed to the heating means 50 by the circulation pump 7 installed on the incoming water pipe 6 through the incoming water pipe 6 connected to the lower part of the hot water storage tank 1. The water heated by the heating means 50 becomes high-temperature hot water, and is conveyed from the heating means 50 to the hot water storage tank 1 via the hot water supply pipe 8 connected to the upper part of the hot water storage tank 1 and stored therein. A relief valve 9 for releasing the pressure in the hot water storage tank 1 is connected to the upper part of the hot water storage tank 1. Hot water stored in the hot water storage tank 1 is discharged through a hot water supply pipe 10 connected to the upper part of the hot water storage tank 1, and mixed with water supplied from the water supply pipe 2a by a mixing valve 11. The mixing valve 11 mixes hot water and water so that the temperature is preset by the user using an external instruction system such as a remote controller (not shown), and flows the mixed hot water into the hot water supply pipe 12. The hot water storage tank unit 100 is connected to an external hot water supply pipe 21 connected to a hot water supply terminal such as a bathtub, a shower, or a kitchen or a bathroom faucet. The mixed hot water supply pipe 12 is connected to the external hot water supply pipe 21. The hot water adjusted to the set temperature by the mixing valve 11 is supplied to the hot water supply terminal through the mixed hot water supply pipe 12 and the external hot water supply pipe 21.

  Further, a drain plug 13 is installed on the water inlet pipe 6 below the hot water storage tank 1. When the user does not use the water heater or performs maintenance, the water tap 14 on the external water supply pipe 3 is closed to stop the water supply, and then the drain tap 13 is opened to drain the water in the hot water storage tank 1. Can be removed.

  FIG. 2 is a cross-sectional view of the water supply pipe connection port unit 4. As shown in FIG. 2, the water supply pipe connection port unit 4 has a main body 41, a connection port 42 to which the water supply pipe 2b is connected, and a connection port 43 to which the external water supply pipe 3 is connected. The main body 41 includes a check valve 15, a strainer 16, and a drain valve 17. The check valve 15 has a function of preventing water from flowing backward from the water supply pipe 2b side to the external water supply pipe 3 side. By providing this check valve 15, it is possible to reliably prevent the water in the hot water storage tank 1 from flowing backward into the external water supply pipe 3 and contaminating the water quality. The strainer 16 has a function of removing small dust contained in water that is passed through the external water supply pipe 3.

  The water drain valve 17 has a function of allowing water in the flow path between the check valve 15 and the pressure reducing valve 5, that is, water in the water supply pipe 2b to be discharged. Although the detailed illustration of the drain valve 17 is omitted, a spring constant is set so that the valve is opened when the pressure in the internal space 44 of the water supply pipe connection port unit 4 (main body 41) becomes lower than a predetermined set pressure. And a packing as a seal member that ensures liquid tightness when the valve is closed. The set pressure is set to a pressure lower than the pressure of the external water source acting from the external water supply pipe 3. When this hot water storage type hot water heater is used, the water source pressure from the external water supply pipe 3 acts on the internal space 44 of the water supply pipe connection port unit 4, whereby the drain valve 17 is maintained in the closed state.

  In general, immediately after the hot water storage tank unit 100 is installed, a contractor who installs the hot water storage water heater passes water from the external water supply pipe 3 to the hot water storage tank unit 100 to fill the hot water storage tank 1, and the pipes in various places. Check if the connection is securely connected. After that, the contractor closes the water supply stop cock 14 on the external water supply pipe 3 in order to prevent water from staying in the hot water storage tank 1 for a long period of time, except when the hot water storage type hot water heater is started immediately. It is common to drain the water in the hot water storage tank 1 by opening the drain plug 13. Similarly, during maintenance of parts in the hot water storage tank unit 100, the water supply stop cock 14 is closed and the drain plug 13 is opened to drain the water in the hot water storage tank 1.

  If the water shut-off valve 14 is closed as described above and the water in the hot water storage tank 1 is drained from the drain plug 13, the pressure on the secondary side (downstream side) of the water shut-off tap 14 will drop, so the water supply pipe connection The pressure in the internal space 44 of the mouth unit 4 is lower than the set pressure of the drain valve 17. As a result, the drain valve 17 is opened by the spring force, and the water in the flow path between the check valve 15 and the pressure reducing valve 5, that is, the water in the water supply pipe 2b is discharged from the drain valve 17. The The drain valve 17 is located outside the outer case 20. For this reason, the water flowing out from the drain valve 17 is surely discharged to the outside of the outer case 20 and does not remain in the outer case 20.

  If the drain valve 17 is not provided, when the water in the hot water storage tank 1 is drained, the water in the flow path (in the water supply pipe 2b) between the check valve 15 and the pressure reducing valve 5 is not drained. Remain. For this reason, when the outside air temperature becomes low during the period after the hot water storage tank unit 100 is installed or during the maintenance period, water in the flow path (in the water supply pipe 2b) between the check valve 15 and the pressure reducing valve 5 is removed. Freezing and the expansion of the volume may damage parts such as the pressure reducing valve 5 and the water supply pipe connection port unit 4.

  On the other hand, in this hot water storage type hot water heater, as described above, when the water in the hot water storage tank 1 is drained, it is in the flow path (in the water supply pipe 2b) between the check valve 15 and the pressure reducing valve 5. Since water is automatically drained from the drain valve 17, no water remains in this flow path. Therefore, water in the flow path (inside the water supply pipe 2b) between the check valve 15 and the pressure reducing valve 5 also when the outside air temperature becomes low during the period after the hot water storage tank unit 100 is installed or during the maintenance period. Since the component does not freeze, it is possible to reliably prevent parts from being damaged by freezing.

  Moreover, it is preferable that the constituent material of the drain valve 17 is a material having a low thermal conductivity as compared with the constituent material of an adjacent component (for example, the main body 41) of the water supply pipe connection port unit 4. By comprising in this way, since the temperature fall rate of the drain valve 17 is suppressed at the time of outside temperature fall, it can prevent reliably that the drain valve 17 stops by freezing before water drains. .

  Furthermore, the drain valve 17 may be configured to be able to forcibly open by an external operation. In this case, the drain valve 17 may be configured to be electrically openable by a switch operation from the outside of the water supply pipe connection port unit 4, or the water drain valve 17 may be manually operated from the outside of the water supply pipe connection port unit 4. May be configured to be openable. With this configuration, even if the drain valve 17 is stuck and does not operate, the drain valve 17 is forcibly opened so that the check valve 15 and the pressure reducing valve 5 The water in the channel between them can be drained.

  In the present embodiment, the connection port 43 to which the external water supply pipe 3 is connected, the check valve 15, and the drain valve 17 are integrally provided in the water supply pipe connection port unit 4. , Reducing the number of parts, and facilitating assembly. However, in the present invention, these are not necessarily provided integrally.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2a Water supply piping 2b Water supply piping 3 External water supply piping 4 Water supply piping connection unit 5 Pressure reducing valve 6 Water supply piping 7 Circulation pump 8 Hot water discharge piping 9 Relief valve 10 Hot water supply piping 11 Mixing valve 12 Mixed hot water supply piping 13 Drain plug 14 Water supply stop Water faucet 15 Check valve 16 Strainer 17 Drain valve 20 Outer case 21 External hot water supply piping 41 Body 42, 43 Connection port 44 Internal space 50 Heating means 100 Hot water storage tank unit

Claims (6)

A hot water storage tank,
A water supply pipe connected to the hot water storage tank and guiding water supplied from an external water source to the hot water storage tank;
A pressure reducing valve provided in the middle of the water supply pipe for reducing the water pressure of the external water source;
Provided on the upstream side of the pressure reducing valve, and a check valve for regulating a backflow;
It is provided in the flow path between the check valve and the pressure reducing valve, and is closed when the water pressure of the external water source is applied, and is opened when the water pressure of the external water source is not applied. A drain valve for draining water in the flow path;
Hot water storage type water heater equipped with. An outer case for accommodating the hot water storage tank;
The hot water storage type water heater according to claim 1, wherein the water drain valve is located outside the outer case.   The hot water storage type hot water supply apparatus according to claim 1 or 2, wherein the drain valve can be forcibly opened by an external operation.   The hot water storage type hot water heater according to any one of claims 1 to 3, wherein a constituent material of the drain valve is a material having a lower thermal conductivity than a constituent material of a component adjacent to the drain valve.   The drain valve closes when the applied pressure is equal to or higher than a predetermined set pressure lower than the water pressure of the external water source, and opens when the applied pressure becomes lower than the predetermined set pressure. The hot water storage type hot water supply apparatus according to any one of claims 1 to 4, further comprising a spring having a spring constant set as described above.   The connection port to which an external water supply pipe that supplies water from an external water source is connected, the check valve, and the drain valve are integrally provided. Hot water storage water heater.

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