JPH08121867A - Hot water supply device - Google Patents

Abstract

PURPOSE: To ensure draining of each circuit to prevent freezing when the operation of a hot water supply device is suspended by a method wherein the opening/ closing control valves for a heating circuit and a bypass circuit are both opening/closing valve control device activated by a water flow stopping signal supplied from a water flow stopping detection means. CONSTITUTION: A water supply circuit 1 to a heat exchanger J heated by a gas burner B is branched off upstream of the heat exchanger J into a heating circuit 1a leading to the heat exchanger J and a bypass circuit 1b leading thereto. The heating circuit 1a and the bypass circuit 1b are joined downstream of the heat exchanger J. Opening/closing control valves 2a and 2b respectively are provided on these two circuits and are both opened by an opening/closing valve control device C activated by the water flow stopping signal supplied from a water flow stopping detection means 300. By this device draining of each circuit is surely effected to prevent its freezing, when the operation of the hot water supply device is suspended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply system, and more particularly to a hot water supply system having a bypass mixing type heat exchanger.

[0002]

2. Description of the Related Art In recent hot water supply devices, in order to prevent corrosion due to drainage of a heat exchanger, or in a cold water sand phenomenon at the time of re-leaving hot water (a phenomenon in which cold water temporarily comes out after hot water comes out at the time of re-leaving hot water). In order to prevent the water supply circuit to the heat exchanger,
A so-called bypass mixing method is adopted in which a circuit to be heated via a heat exchanger and a bypass circuit bypassing the heat exchanger are branched so as to be joined on the downstream side of the heat exchanger. By controlling the ratio of the flow rate of the circuit to be heated and the flow rate of the bypass circuit, the temperature of the heat exchanger section can be maintained at a relatively high temperature regardless of the amount of hot water discharged or the temperature of hot water discharged. Drain can be prevented from occurring in the heat exchanger. Further, the cold water sand phenomenon can be easily prevented depending on the control method.

However, in this type of water heater, the circuit to be heated and the bypass circuit are always open. on the other hand,
When the total flow rate is very small, the gas burner for heating the heat exchanger may be in a combustion stopped state, and in such a case, drainage is likely to occur in the heat exchanger.

In order to eliminate such inconvenience, a normally closed type control valve is inserted downstream of the branch point of the bypass circuit in the heated circuit, and a normally open type control valve is inserted in the bypass circuit. Japanese Patent Application Laid-Open No. 5-180510 proposes a system in which the control valve is controlled to open and close according to tapping conditions and the like. With this type, under a very small flow rate condition where the gas burner does not burn, the passage on the heat exchanger side is shut off by closing the control valve inserted in the heated circuit, so the drain in the heat exchanger concerned is closed. Can be prevented.

Further, since the control valve of the bypass circuit is of the normally open type and the control valve of the circuit to be heated is of the normally closed type, the cold water can be taken out from the hot water supply device as it is while the operation of the hot water supply device is stopped. . At this time, since cold water does not flow to the heated circuit side, it is possible to prevent drainage in this state. However, in this conventional device, since the upstream end of the heated circuit is closed by the normally closed control valve, even if water is drained to prevent freezing of the water circuit when the water heater is not operating. However, water cannot be drained from the portion of the circuit to be heated, and there is a risk of damage to the circuit portion due to freezing.

The present invention has been made in view of the above points, and it is a "heat exchanger heated by a gas burner (B)".
The water supply circuit (1) to (J) is connected to the heated circuit (1a) through the heat exchanger (J) and the heat exchanger (J) on the upstream side of the heat exchanger (J).
To a bypass circuit (1b) that bypasses the heat exchanger (J), and the heated circuit (1a) and the bypass circuit (1b) are merged on the downstream side of the heat exchanger (J). In a hot water supply system in which an open / close control valve is inserted and open / close control can be performed by the open / close control valve control device according to the hot water discharge condition, '' it is possible to reliably remove water to prevent freezing of each circuit in the operation stopped state. The task is to do.

[Invention of Claim 1]

[0008]

[Technical Means] A technical means of the present invention for solving the above-mentioned problem is to provide "a water flow stop detection means (300) for detecting a water flow stop state in a water heater, and the opening / closing valve control device. A means for opening both the open / close control valves of the heated circuit (1a) and the bypass circuit (1b) by the water flow stop signal output from the detecting means (300) is provided. (See Fig. 1)

[0009]

The above technical means operates as follows. Since the open / close control valves (2a) (2b) are controlled to open / close by the open / close control valve control device according to the hot water discharge condition, the open / close control is performed under various hot water discharge conditions, including the case of taking out cold water, as in the case of the conventional one. The control valves (2a) and (2b) are controlled, and depending on the control mode, the heat exchanger (J) can be used in a mode in which drainage does not occur.

Further, when the output from the water flow stop detecting means (300) is input, the opening / closing control valves (2a) and (2b) are both opened by the opening / closing control valve control device, so that the water heater is drained. In this case, both the circuit to be heated (1a) and the bypass circuit (1b) are kept in communication with the drainage section.

[0011]

[Effect] When draining water from the water heater, the heated circuit (1
Since both a) and the bypass circuit (1b) are maintained in communication with the drainage part, it is possible to drain the entire water circuit in the water heater when draining water to prevent freezing. There is no need to worry about death. Therefore, it is possible to surely prevent freezing.

[Other inventions] The invention defined in claim 2 is the "branch point (11) of the heated circuit (1a) and the bypass circuit (1b)"
A flow rate sensor (3) for measuring the total flow rate to the two circuits is installed on the upstream side of the flow rate sensor. This flow rate sensor (3) is used as the water flow stop detection means (300), and the zero output of the flow rate sensor (3) is provided. The signal was used as a water flow stop signal. "

The water flow stop detecting means in the invention of claim 1
As (300), a water flow switch that can only detect the presence / absence of water flow can be adopted, but in the invention of claim 2, a flow rate sensor for detecting the tapping condition.
Since (3) is the water flow stop detecting means (300), there is an advantage that the detecting means can be simplified. The invention defined in claim 3 is the same as that of the invention of claim 2, in which "gas burner (B)" is used.
Is configured so that its thermal power is controlled by the water flow detected by the flow rate sensor (3) and the set hot water temperature, and the combustion is stopped when the detected water flow rate is below the minimum set flow rate.The on-off valve control device uses the flow sensor (3) When the detected water volume is at least the minimum set water volume and the hot water outlet temperature is in the normal operating temperature range, the open / close control valve (2a) provided in the heated circuit (1a) and the open / close control valve (2b) provided in the bypass circuit (1b) are both In addition to opening the valve, only the open / close control valve (2b) is closed during high-temperature hot water supply, and the open / close control valve (2a) is opened in the set flow range in which the amount of water detected by the flow rate sensor (3) stops combustion in the gas burner (B). ) Only to close the valve.

This device operates as follows. When using hot water in the normal temperature range, both the open / close control valves (2a) and (2b) are maintained in the open state, and the hot water on the heated circuit (1a) side and the cold water on the bypass circuit (1b) side are separated. It is mixed and discharged at the confluence of these two circuits. On the other hand, at the time of hot water discharge, only the open / close control valve (2b) is closed and water is supplied only through the heated circuit (1a) side, so that the hot water on the heated circuit (1a) side is discharged as it is. When the amount of water detected by the flow rate sensor (3) reaches the minimum flow rate state, the output of this will close only the on-off control valve (2a), and the water at this flow rate will flow from the water heater via the bypass circuit (1b) side. Is discharged.

At this time, the gas burner (B) is not combusted and the heat exchanger is in a non-heated state, but since there is no water flow in the heated circuit (1a) including this heat exchanger, the drainage Can also be prevented. In the operation stopped state, the open / close control valve (2a) (2
Both b) are kept open, so when draining water to prevent freezing, the heated circuit (1a) and bypass circuit (1a)
If the upstream side of the branch point of b) is opened, water can be drained from the downstream side of the heated circuit (1a) and the bypass circuit (1b).

With the above operation, the following effect is obtained in addition to the effect of the invention of claim 2 described above. When the amount of water detected by the flow sensor (3) falls below the minimum set flow rate, the circuit on the heated circuit (1a) side is shut off, so the gas burner (B) does not burn, that is, the heat exchanger is not heated. Therefore, it is possible to prevent the generation of drain due to water being passed through the bypass circuit (1b).

[0017]

Embodiments of the present invention described above will now be described in detail with reference to the drawings. The first embodiment, as shown in FIG. 2, is a heat exchanger.
The proportional valve (V) controls the combustion amount of the gas burner (B) that heats (J). Also, the heated circuit (1a) and the bypass circuit (1b) in the water supply circuit (1) to the heat exchanger (J).
A flow sensor (3) is inserted upstream of the branch point (11) of
A main valve (31) is inserted in the inlet side circuit (10) connected to this water supply circuit (1) by a joint (32), and the amount of water supplied to the water supply circuit (1) is detected by the flow rate sensor (3). Has been done.

An open / close control valve (2a), which is a solenoid valve, is inserted in the heated circuit (1a) passing through the heat exchanger (J), and the bypass circuit (1b) bypassing the heat exchanger (J) is the same. An opening / closing control valve (2b), which is a solenoid valve, is inserted in the valve, and the opening / closing control valve is a normally open solenoid valve. And the heated circuit (1a)
A water faucet (13) is connected to the downstream side of the confluence point (12) of the bypass circuit (1b).

In this embodiment, the temperature on the downstream side of the confluence point (12) is detected by the temperature sensor (S), and as shown in FIG. 3, the detected temperature and the tapping temperature are 35 ° C to 85 ° C.
The set value from the tap water temperature setting device (4) and the amount of water detected by the flow rate sensor (3) are input to the control device (C), and the output from this control device (C) Proportional valve
The opening and closing control valves (2a) and (2b) are controlled while the (V) opening is controlled.

For example, when the hot water outlet temperature is set to the normal operating temperature, the opening / closing control valves (2a) and (2b) are maintained in the open state, and the amount of water detected by the flow rate sensor (3) and the above setting are set. The controller (C) calculates the combustion gas amount of the gas burner (B) from the relationship with the temperature and sets the opening of the proportional valve (V) to an opening corresponding to this. As a result, the hot water at the set temperature will meet (1
It can be taken out from 2). A faucet (1
Even if the opening degree of 3) is changed and the amount of tapping water changes, the control device (C) sequentially executes the above calculation in accordance with the change, so that the tapping temperature is maintained at the set temperature.

When the opening of the faucet (13) is extremely narrowed on the downstream side of the confluence point (12), and the detected water amount of the flow rate sensor (3) reaches the minimum set water amount, at this time, the control device (C) Depending on the output
The on-off control valve (2a) is in the conductive state and is closed, and only the on-off control valve (2b) is in the non-conductive state and is maintained in the open state, and the heat exchanger (J) is in a state in which water is not passed. . Therefore, it is possible to prevent the occurrence of drainage due to the passage of cold water with residual heat.

Next, the set temperature is a predetermined high temperature (for example, 8
If set to 0 ° C. or higher), the opening / closing control valve (2a) is made non-conductive and maintained in the open state, and the opening / closing control valve (2b) is made conductive and maintained in the closed state. As a result, water will be passed through only the heated circuit (1a) side, the combustion gas amount under this condition will be calculated, and the opening of the proportional valve (V) will be set to an opening corresponding to this. To be done.

When the operation is stopped, the open / close control valves (2a) and (2b) are both normally open solenoid valves, and thus the valve is returned to the open state. To drain water in this state to prevent freezing,
Close 1) and open faucet (13). The main valve (31) is of a known type in which the downstream side thereof communicates with the atmosphere side and the upstream side circuit is shut off in the closed state. Therefore, the faucet (1
Water in the circuit to be heated (1a) and the bypass circuit (1b) is discharged from 3). There is no need to worry about water remaining.

As shown by an imaginary line in FIG. 2, if the valve body (33) for sucking air is separately provided on the downstream side of the main valve (31), the main valve (31) is the above-mentioned. It is not necessary to have the special configuration as described above, and a normal on-off valve may be used. Further, for draining water, a drain valve dedicated to draining water may be provided separately from the faucet (13). Further, in the first embodiment, as shown in FIGS. 2 and 3, when the operation switch SW provided in the remote control device is turned on, the temperature sensor (S), the flow rate sensor (3) and the control device are controlled.
(C) becomes conductive, and the output of this control device (C) causes each part of the output device such as the on-off control valve (2a) to operate. Therefore, the flow rate sensor (3) becomes the water flow stop detection means (300) defined in claim 1, and the control device (C) defines the water flow stop signal from the water flow stop detection means (300) defined in claim 1. Output circuit to be heated (1a) and bypass circuit (1b)
The on-off valve control device equipped with a circuit for opening both the on-off control valve and the on-off control valve (2a) (2b) is a normally open type, so even when the operation switch SW is turned off. The control state by the control device (C) is maintained when the water flow is stopped.

Instead of the first embodiment, as shown in FIG. 4, the flow sensor (3) and the opening / closing control valve (2a) are provided with the operation switch.
The power supply is connected without SW and the flow rate sensor (3) constantly detects the flow rate.When the flow rate is detected, the open / close control valve (2a) inserted in the heated circuit (1a) is closed and closed. An auxiliary control device (C ₁ ) for operating the valve may be provided, and the auxiliary control device (C ₁ ) may also be constantly supplied with electricity.

In this embodiment, when the power plug is not pulled out or there is a power failure, regardless of whether the contacts of the operation switch SW are opened or closed, the power is always supplied, and after the hot water supply is stopped, the operation switch SW is turned on. Even if the faucet (13) is opened immediately after turning it off, the opening / closing control valve (2a) will be closed by the output of the auxiliary control unit (C ₁ ) that inputs the output of the flow sensor (3). The disadvantage that cold water flows into the non-heating circuit (1a) equipped with the heat exchanger (J) is avoided.

When water does not flow, that is, the flow sensor
When the output of (3) is "0", the opening / closing control valve (2a) is kept open together with the opening / closing control valve (2b). A water flow switch may be used instead of the flow rate sensor (3) as an input device to the auxiliary control device (C ₁ ) for determining the presence or absence of water flow. In this case, the control device
The combination of (C) and the auxiliary control device (C ₁ ) is the on-off valve control device defined in claim 1.

Further, the open / close control valves (2a) and (2b) may be pilot solenoid valves as shown in FIG. In the figure, the pilot solenoid valve is composed of an electromagnet (5) and a valve device.
(6) consists of and. A main circuit and a pilot circuit are formed in the valve box (60) of the valve device (6). A normally open diaphragm valve (62) is provided facing the valve seat (61) formed in the main circuit and spaced apart from the valve seat (61).
Due to the partition plate (63), the vacant space formed in the mounting part of (5) is
It is partitioned into a first chamber (64) on the electromagnet (5) side and a second chamber (65) on the diaphragm valve (62) side.

The first empty chamber (64) communicates with the upstream side of the valve seat (61), and the second empty chamber (65) has a bypass circuit (1) in this embodiment.
It is connected to the downstream side of the opening / closing control valve (2b) provided in b). Therefore, in the valve box (60), a leak hole (66) is formed in the peripheral wall of the second empty chamber (65).
Is formed, and the leak hole is communicatively connected to the downstream side of the opening / closing control valve (2b) provided in the bypass circuit (1b). Further, the partition plate (63) has a valve port (67) formed therethrough,
The valve body (52) attached to the tip of the rod (51) of the electromagnet (5) faces the valve opening (67). The rod (51) is biased by a spring in a direction to advance from the electromagnet (5), and is retracted by the biasing force of the spring when the electromagnet (5) is brought into conduction.

In this pilot type solenoid valve, the electromagnet (5)
The diaphragm valve (62) is open when is closed, but when the electromagnet (5) is turned on and the rod is closed,
Since the (51) is pulled up, the valve body (52) opens and the valve seat (61)
The pilot flow path of the path of the upstream side → the first vacant chamber (64) → the valve opening (67) → the second vacant chamber (65) → the leak hole (66) communicates with each other. The leak amount of the leak hole (66) is preset to a predetermined value in relation to the water absorption pressure, and the opening / closing control valve (2b)
Since there is an orifice (69) on the outlet side of the valve box (60)
The diaphragm valve (62) closes due to the differential pressure between the main circuit and the pilot circuit inside.

A differential pressure responsive pilot solenoid valve is also adopted for the opening / closing control valve (2b), and the leak hole (66) and the downstream side of the orifice (69) are connected to each other,
Similarly, the valve is closed when the electromagnet (5) becomes conductive. As described above, when the opening / closing control valves (2a) and (2b) are made to be differential pressure responsive pilot solenoid valves, the power consumption at closing is less than that of direct type normally open solenoid valves. .

In each of the above embodiments, the opening / closing control valve (2
As a) and (2b), a normally open solenoid valve is adopted, but both may be normally closed solenoid valves. In this case, it is assumed that each unit is always connected to the power supply. Then the flow sensor
(3) and water flow stop detection means (30
The output from (0) is always input to the on-off control valve control device, and when the water flow stop signal is input to the on-off control valve control device, the on-off control valve (2
When a) and (2b) are brought into conduction and both valves are opened, the same operation as in each of the above-described embodiments is performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the principle of the present invention.

FIG. 2 is an explanatory diagram of the entire apparatus according to the embodiment of the present invention.

FIG. 3 is a block diagram of a control system

FIG. 4 is a block diagram of another control system.

FIG. 5 is an overall schematic explanatory diagram when the opening / closing control valves (2a) and (2b) are pilot solenoid valves.

[Explanation of symbols]

 (B) ・ ・ ・ Gas burner (J) ・ ・ ・ Heat exchanger (1) ・ ・ ・ Water supply circuit (1a) ・ ・ ・ Heated circuit (1b) ・ ・ ・ Bypass circuit (11) ・ ・ ・ Branch point ( 3) ・ ・ ・ Flow sensor (2a) ・ ・ ・ Open / close control valve (2b) ・ ・ ・ Open / close control valve (300) ・ ・ Water flow stop detection means

Claims (3)

[Claims] 1. A water supply circuit (1) to a heat exchanger (J) heated by a gas burner (B) is provided with a heated circuit (1) upstream of the heat exchanger (J) via the heat exchanger (J). 1a) and the heat exchanger
(J) is branched to a bypass circuit (1b) that bypasses, and the heated circuit (1a) and the bypass circuit (1b) are merged on the downstream side of the heat exchanger (J). A water flow stop detector (300) for detecting the water flow stop state in the water heater is provided in the hot water supply device in which the open / close control valve is inserted in each of the A hot water supply apparatus in which the opening / closing valve control device includes means for opening both the opening / closing control valves of the heated circuit (1a) and the bypass circuit (1b) in response to the water flow stop signal output from the water flow stop detection means (300). . 2. A flow rate sensor (3) for measuring the total flow rate to the two circuits is provided upstream of the branch point (11) of the heated circuit (1a) and the bypass circuit (1b). The water heater according to claim 1, wherein the sensor (3) is a water flow stop detection means (300), and a zero output signal of the flow rate sensor (3) is a water flow stop signal. 3. A gas burner (B) is provided with this flow sensor (3).
The thermal power is controlled by the detected water flow and the set hot water temperature and the combustion is stopped when the detected water amount is less than the minimum set flow rate.The open / close valve controller controls the flow rate sensor (3) when the detected water amount is more than the minimum set water amount. In addition, when the set hot water temperature is in the normal operating temperature range, the open / close control valve (2a) provided in the heated circuit (1a) and the open / close control valve (2b) provided in the bypass circuit (1b) are both opened, and at the time of high temperature hot water supply. Only the opening / closing control valve (2b) is closed, and only the opening / closing control valve (2a) is closed in the set flow rate range where the combustion amount of the gas burner (B) is stopped by the flow rate sensor (3). The water heater according to claim 2.