JPH0364782B2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention instantaneously heats water with a burner, heater, etc.
This invention relates to prevention of after-boiling of instantaneous water heaters that supply hot water.

Conventional Structure and Problems There has been a conventional instantaneous water heater of this type as shown in Fig. 1.

In FIG. 1, the heat exchanger 1 includes water supply pipes 2,
2' is connected, and the water supply pipe 3 is also connected. A bypass pipe 4 branches off from the water supply pipe 2 and joins the hot water supply pipe 3 at a tank 5. Water is heated by a burner 6, turned into hot water by a heat exchanger 1, mixed with water in a tank 5 depending on conditions, and supplied from a faucet 7 or a shower 8 at the terminal. 9 is a drain pipe provided in the middle of the heat exchanger. Water supply pipe 2'
valve A10 is installed in the valve A10, and valve B is installed in the bypass pipe 4.
11, the drain pipe 9 is provided with a valve C12. These valves are adapted to move in conjunction with cams A44, B15, and C16 provided on the operating shaft 13. The operation of this conventional example is that when the operating shaft 13 is pressed and rotated at the pilot ignition position at the start of hot water supply, the valve C12 is initially closed by the cam C16, and the valve B11 of the bypass 4 is opened, so that water flows through the bypass passage. Go through 4 and enter tank 5. Thereafter, when the rotation is continued, the cam B15 closes the valve B11. At the same time, the valve A10 is opened by the cam A14, and water is passed to the water supply pipe 2' and the heat exchanger 1. At the same time, gas is supplied to the burner 6 and burned, and hot water flows from the hot water supply pipe 3 to the tank 5. The water is then supplied from the faucet 7 or the shower 8. To stop using hot water, press operation shaft 1.
3 is reversely rotated to cut off the gas supply to the burner 6, the valve A10 is closed, and at the same time, the valve B11 is opened to connect the bypass 4,
Eventually, at the pilot ignition position, valve B11 is closed and valve C12 is opened to drain water. For this reason, when starting to use the water heater, after water enters the tank 5 from the bypass pipe 4, the valve A10 is opened and the hot water is heated. The hot water is supplied at a lower temperature in the tank 5 to prevent the after-boiling phenomenon.

However, this conventional instant water heater had the following problems.

(1) The valves A, B, and C, the corresponding cams A, B, and C, and the tank 5 were required, resulting in a complicated configuration and poor reliability and cost.

(2) Every time the use is stopped, the valve C12 is opened and the water is drained, so there is heat loss, even if it is a small amount, and some parts of the tank 5, hot water pipes 3, and heat exchanger 1 are damaged when refilling hot water. Since the air that had been in the system is forced out and supplied to the faucet 7 and shower 8, hot water protrudes discontinuously, causing problems in terms of usability and safety.

Purpose of the Invention The present invention provides an instantaneous water heater that solves these conventional problems, and provides an instantaneous water heater that has a simple configuration, satisfies safety and energy savings, and prevents after-boiling. With the goal.

Structure of the Invention To achieve this object, the present invention provides a burner,
A heater that is heated by a heater, etc., a heat exchanger that is heated by this heater, a water supply pipe and a hot water supply pipe that are connected to this heat exchanger, and a system that branches off from the water supply pipe and bypasses the top of the heat exchanger. a bypass pipe that joins the hot water supply pipe; a check valve that closes the flow path of the bypass pipe by the water flow and opens the flow path by stopping the water flow; An instantaneous water heater is configured with a controller that controls the heater based on a signal from a check valve, and when hot water supply is stopped, hot water in the heat exchanger and water in the bypass pipe are mixed by natural circulation. By doing so, the temperature of the post-boiling hot water is lowered.

DESCRIPTION OF EMBODIMENTS Next, embodiments of the present invention will be described with reference to FIGS. 2 and 3.

FIG. 2 shows an example in which the present invention is applied to a gas instantaneous water heater. A burner 17 heats the heat exchanger 18. Water supply pipes 19, 19' and hot water supply pipes 20, 20' are connected to the heat exchanger 18. A bypass pipe 21 branches off from the middle of the water supply pipe 19, and this bypass pipe 21 detours above the heat exchanger 18 and joins the hot water supply pipe 20. The bypass pipe 21 is provided with a check valve 22 that serves as a means for detecting the presence or absence of hot water supply and a valve that closes the flow path by the water flow and opens the flow path by stopping the water flow. At this time, the bypass pipe 21 is opened. A temperature detector 23 is provided in the hot water pipe 20, and a gas proportional valve 27 is connected via a controller 26 to obtain the set temperature of a temperature setting device 25 provided near the faucet 24.
is adjusted. The check valve 22 is constructed as shown in FIG. Inside the valve frame body 28, a ball 29 and a ball receiver 30, which are check valve bodies, are provided. When hot water is being supplied, the ball 29 moves upward in the figure, and when hot water is not being supplied, it descends downward to open the bypass pipe 21. The check valve 22 also serves as a flow rate switch that detects the position of the ball 29.

As another embodiment of the check valve 22, for example, a structure may be considered in which a flow rate switch and an electric valve are combined, and the flow rate switch detects the stoppage of hot water supply, and the electric valve opens a bypass pipe.

In addition, as shown in FIG. 2, in this embodiment, the connection position of the hot water supply pipe 20' connected to the heat exchanger 18 is arranged above the connection position of the water supply pipe 19'. The structure has no downward slope section.

Next, the operation of this embodiment will be explained.

When the faucet 24 is opened, the burner 17 is ignited by a signal from the check valve 22 which also serves as a flow rate switch, and the temperature of the water is monitored by the temperature detector 23 so that the set temperature of the setting device 25 is obtained. The opening degree of the proportional valve 27 is adjusted. During hot water supply, the ball 2 of the check valve 22
9 rises to block the passage and throttle the flow of water through the bypass 21.

When the faucet 24 is closed and hot water supply is stopped, combustion in the burner 17 is stopped by a signal from the check valve 22, and the check valve 22 fully opens the bypass pipe 21. When combustion stops, the flow of water stops, so the heat exchanger 18
The water or hot water inside is gradually heated above the set value by the residual heat already added to the heat exchanger 18. A bypass pipe 21 provided above the heat exchanger 18 is filled with water, and the temperature at the inlet of the heat exchanger 18 is close to the water temperature. Since the check valve 22 of the bypass pipe 21 is open, the superheated water in the heat exchanger 18 flows into the hot water pipe 2 due to the difference in specific gravity.
0' to the bypass pipe 21, and conversely, the water in the bypass pipe 21 passes through the water supply pipe 19' to the heat exchanger 18.
, and a so-called natural circulation occurs.

Therefore, the hot water that has been heated to a fairly high temperature near the outlet of the heat exchanger 18 mixes with the low temperature portion and becomes below the set temperature. Therefore, when refilling hot water, the faucet 24
Even if the water is opened, hot water will not come out and after-boiling will be prevented. Furthermore, since the temperature within the heat exchanger 18 is cooled relatively gradually through natural circulation, cold water within the heat exchanger is supplied during reheating within a short period of time, compared to a method in which cold water is immediately replaced. Pre-chilling phenomenon can be prevented.

In addition, the ball 29 may be damaged by the bypass pipe 21 due to scale components or foreign matter contained in the water during hot water supply.
Even if the faucet is locked in the closed state and the after-boiling prevention function is impaired, the operation will not stop even if the faucet 24 is closed because the check valve 22 also serves as a means for detecting the presence or absence of hot water supply. If a dedicated display means is provided, the user can detect abnormalities according to the display, and can prevent the risk of being exposed to hot water after refilling.

If the ball 29 locks in the ball receiver 30 for the same reason while hot water supply is stopped, the heater will not operate even if the faucet 24 is opened, so the bypass pipe 21
Water flows through the burner, and even if the burner 17 is fully opened, only lukewarm water is obtained, and the user can avoid wasting time waiting for the temperature to reach an appropriate temperature without knowing that there is a malfunction.

Effects of the Invention The present invention provides a bypass pipe that bypasses a heat exchanger for post-boiling in an instantaneous water heater, and a hot water supply system that uses a water flow to close the flow path of the bypass pipe and opens the flow path by stopping the water flow. Since this is performed using a check valve that also serves as a means for detecting presence or absence, it has the following effects.

(1) By combining a bypass pipe and a check valve with a function to detect the presence or absence of water flow, it is possible to prevent after-boiling and control the heater at the same time, so the configuration is simple, compact, and inexpensive.

(2) Even if the check valve becomes locked due to scale components or foreign objects in the water while hot water is being supplied, the check valve also serves as a means of detecting the presence or absence of hot water supply, so the check valve will not close when the hot water supply is stopped. The user can be informed that an abnormality has occurred and the after-boiling prevention function is impaired, and the risk of being exposed to hot after-boiling water when refilling hot water can be prevented.

(3) If the check valve locks for the same reason while hot water supply is stopped, the check valve will not issue a signal indicating that hot water supply has started and the heater will not operate, so even if the heater is operated at full capacity, Water from the bypass pipe mixes with the system, making it impossible to obtain the proper temperature, which prevents the user from having to wait forever without knowing there is a malfunction.

(4) As the hot water stored in the heat exchanger is gradually cooled by natural convection, it is balanced with the residual heat gradually transferred from the heat exchanger, and cold water is temporarily supplied when hot water is reheated within a short time. This prevents the "pre-chilling" phenomenon.

[Brief explanation of drawings]

Figure 1 is a diagram of a hot water supply system using a conventional instantaneous water heater, Figure 2 is a diagram of a hot water supply system using an instantaneous hot water supply pipe, which is an embodiment of the present invention, and Figure 3 is a diagram of a hot water supply system using an instantaneous hot water supply pipe, which is an embodiment of the present invention. It is a sectional view of a stop valve. 17... Burner (heater), 18... Heat exchanger,
19, 19'...Water supply pipe, 20, 20'...Hot water supply pipe, 21...Bypass pipe, 22...Check valve (valve).

Claims (1)

[Claims] 1 A heater such as a burner or heater, a heat exchanger heated by this heater, a water supply pipe connected to this heat exchanger, a hot water supply pipe, and a heat exchanger branched from the water supply pipe at a position. A bypass pipe that detours above and joins the hot water supply pipe, and a means for detecting the presence or absence of hot water supply that closes the flow path of the bypass pipe by a water flow and opens a flow path by stopping the water flow. An instant water heater comprising: a check valve; and a controller that controls the heater based on a signal from the check valve.