JPH03204555A - Hot water supplying mechanism for instantaneous water heater - Google Patents

Abstract

PURPOSE:To shorten time of stabilizing an output hot water temperature by controlling a burner for heating a heat exchanger at a hot water temperature to a predetermined temperature higher than a set temperature based on the hot water temperature of a hot water passage, and controlling feed back so as to hold the set temperature based on the hot water temperature sensed by a temperature sensor of a confluent passage. CONSTITUTION:A mixing valve 4 is composed to move a valve body 8 by a heat responsive element 7 provided in a confluent passage to vary a flow rate ratio of a water passage 5 to a hot water passage 1, and provides an operating mechanism 9 for biasing the element. The mechanism 9 is composed to operate corresponding to the set temperature of an output hot water temperature setter 14, and temperature sensors 15a, 15b are provided at the downstream side of a heat exchanger 3 in the passage 1 and a confluent passage 6. A burner 12 for heating the exchanger 3 is so controlled for the hot water temperature as to be a higher predetermined temperature than the set temperature based on the hot water temperature sensed by the sensor 15a and the set temperature, and controlled to be fed back so as to hold the set temperature based on the hot water temperature sensed by the sensor 15b of the passage 6.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a hot water supply mechanism for an instantaneous water heater.

(Prior art and its problems) In a conventional instantaneous water heater, the temperature of the hot water is adjusted by changing the amount of combustion of a burner for heating a heat exchanger. Efforts have been made to widen the combustion range of the burner by using a plurality of burners, etc., but there is a limit, and if the maximum combustion amount is increased, the minimum combustion amount also increases. Therefore, when the temperature of tap water is high in the summer, it is difficult to obtain hot water at an appropriate temperature (for example, about 35° C.) with a small flow rate.

In addition, with this kind of adjustment of the hot water temperature, when used intermittently at relatively short time intervals, high temperature hot water (overshoot) due to after-boiling in the heat exchanger and ignition delay of the heat exchanger heating burner may occur. This caused problems such as cold water mixing (undershoot), and it took a long time for the tap water temperature to stabilize.

The present invention aims to solve this problem.

(Means for Solving the Problems) Means for solving the above problems will be described with reference to drawings corresponding to embodiments. In parallel with the hot water path 1 passing through the exchanger 3,
A water path 5 is provided which branches on the upstream side of the heat exchanger 3 and merges with the water through a mixing valve 4 on the downstream side. an actuating mechanism 9 configured to move to change the flow rate ratio of the water path 5 and hot water path 1 and to bias the thermally responsive element 7;
The operating mechanism 9 is configured to operate in accordance with the set temperature of the hot water outlet temperature setting device 14, and is connected to the downstream side of the heat exchanger 3 in the hot water path J and the +'+ij entry confluence path 6. Temperature sensors 15a and 15b are provided, and the RIIF heat exchanger 3
The burner 12 that heats the temperature sensor 15 of Moekiyu route 1
Based on the hot water temperature detected by a and the set temperature, the hot water temperature is controlled to be a predetermined temperature higher than the set temperature, and the hot water temperature is set based on the hot water temperature detected by the temperature sensor 15b of the merging path 6. The configuration is such that feedback control is performed to maintain the temperature.

(Function) The temperature of the hot water raised in the heat exchanger 3 by combustion in the burner 12 and flowing through the hot water path 1 is mixed with the clean water flowing through the water path 5 at the mixing valve 4, and the temperature is lowered. The hot water flows through the confluence channel 6 and is discharged from the hot water outlet 19. At this time, the thermally responsive element 7 provided in the merging channel 6 moves the valve body 8 in response to the temperature of the hot water in the merging channel 6, so that the flow rate ratio between the water path 5 and the hot water path l changes. In this way, the temperature of the hot water in the confluence channel 6 can be adjusted to a value corresponding to the bias amount of the thermally responsive element 7. This bias amount can be changed by the operating mechanism 9 in accordance with the set temperature of the hot water outlet temperature setting device 14, and thus the hot water temperature can be adjusted by the hot water outlet temperature setting device 14. In this way, the present invention allows hot water heated by the heat exchanger 3 to be cooled down by tap water and then discharged from the hot water outlet 19.
Even when the minimum combustion amount of the burner 12 is relatively large, hot water can be supplied at a low temperature with a small flow rate. In addition, when used intermittently at relatively short time intervals, the hot water in the hot water path 1 may be contaminated with hot water (overshoot) due to after-boiling in the heat exchanger 3 or cold water due to the ignition delay of the burner 12. Even if there is an undershoot, etc., it will not be transmitted to the hot water in the confluence channel 6. The burner 12 is connected to the temperature sensor 1 of the hot water path 1.
Based on the hot water temperature detected by 5a and the set temperature of the outlet temperature setting device 14, the hot water temperature is controlled to be a predetermined temperature higher than the set temperature, and the temperature is detected by the temperature sensor 15b of the confluence channel 6. Since feedback control is performed to maintain the set temperature based on the hot water temperature, the hot water temperature can be maintained at a constant temperature, and stable hot water supply can be performed.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

First, FIG. 1 shows the overall configuration of the present invention. Reference numeral 1 indicates a hot water path passing through a heat exchanger 3 of a water heater 2. A water path 5 is provided in which the water is branched on the L flow side and merged via a mixing valve 4 on the downstream side. As shown in FIG. 3, the mixing valve 4 has a structure in which a valve body 8 is moved by a thermally responsive element 7 provided in a merging channel 6 to change the flow rate ratio between the water path 5 and the hot water path 1. An actuation mechanism 9 such as an electric actuation mechanism for biasing the thermally responsive element 7 is provided. The thermally responsive element 7 is configured to thermally expand by enclosing wax, for example, and the movement direction of the valve body 8 due to the expansion is such that the amount of hot water in the hot water path 1 is decreased and the amount of water in the water path 5 is increased. This thermally responsive element 7 has a structure in which the amount of bias is adjusted by an actuating body 11 via a bias spring lO. It is configured to move in the middle and up and down directions. In the above configuration, Fig. 2(a) shows a state where the amount of hot water in hot water path 1 is large, and the wax expands in this state, causing a thermal response as shown in Fig. 2(b). When the element 7 thermally expands, the valve body 8 is moved downward to reduce the amount of hot water in the hot water path 1, and at the same time, increases the amount of water in the water path 5, causing the temperature of the hot water in the merging path 6 to decrease, and conversely, the temperature of the hot water decreases. When the temperature decreases too much and the thermally responsive element 7 contracts, the valve body 8 is moved upward to reduce the amount of water in the water path 5, and at the same time increase the amount of hot water in the production path 1 to raise the temperature of the hot water in the merging path 6. In this way, the temperature of the water flowing through the confluence channel can be controlled. When the thermally responsive element 7 is biased downward by the actuating mechanism 9, the set temperature can be lowered, and conversely, when the thermally responsive element 7 is biased upward, the set temperature can be increased.

Reference numeral 12 is a burner for heating the heat exchanger 3, 13 is a controller, 14 is a hot water temperature setting device, and 15a,
Reference numeral 15b indicates a temperature sensor such as a thermistor, which is provided downstream of the heat exchanger 3 in the hot water route 1 and at the merging route 6, respectively. Based on the detected hot water temperature and the set temperature of the outlet temperature setting device 14, the hot water temperature is controlled to a predetermined temperature higher than the set temperature, for example, 20 degrees Celsius higher than the set temperature, and The configuration is such that feedback control is performed to maintain the set temperature based on the hot water temperature detected by the temperature sensor 15b of the passage 6. In addition to controlling the combustion amount of the burner 12 as described above, the controller 13 operates the actuation mechanism 9 to set the bias to the thermally responsive element 7 as described above.

In the figure, reference numeral 16 is a water flow switch, 17 is a water flow restriction valve, 18 is a check valve, 19 is a tap hole, and 20 is a return spring, and these operations are the same as those of the conventional system. In addition to the above configuration, the configuration of the water heater 2 and the configuration of the mixing valve 4 are arbitrary, and their operation is also appropriate.

(Effects of the Invention) As described above, the present invention allows hot water heated by a heat exchanger to be cooled down by tap water and then discharged from the hot water outlet. This has the advantage that even when the temperature of tap water is high in the summer, it is easy to obtain hot water at an appropriate temperature (for example, about 35° C.) with a small flow rate. In addition, in the present invention, when used intermittently at relatively short time intervals, the hot water in the production path is exposed to high-temperature hot water (overshoot) due to after-boiling in the heat exchanger and ignition of the burner for heating the heat exchanger. Even if there is cold water mixing (undershoot) due to a delay, the hot water temperature can be maintained at a constant temperature without being transmitted to the hot water in the merging channel, resulting in stable hot water supply.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of the present invention, and FIGS. 2(a) and 2(b) are explanatory cross-sectional views showing the configuration and operation of the embodiment of a mixing valve. Code 1... Manufacturing route, 2... Water heater, 3... Heat exchanger, 4... Mixing valve, 5... Water route, 6... Merging channel,
7... Thermal response element, 8... Valve body, 9... Actuation mechanism,
1o...Bias spring, 11...Operating body, 12.Burner, 13.Controller, 14...Hot water temperature setting device, 15...Temperature sensor, 16...Water switch, 17
...Water flow rate restriction valve, 18...Check valve, 19...Tap water outlet, 20...Return spring. Figure 1

Claims (1)

[Claims] In parallel with a hot water path passing through a heat exchanger of a water heater, a water path is provided that branches on the upstream side of the heat exchanger and joins together via a mixing valve on the downstream side, and the mixing valve is provided in the merging path. The valve body is moved by a thermally responsive element to change the flow rate ratio between the water path and the hot water path, and an actuation mechanism is provided that biases the thermally responsive element, and the actuation mechanism adjusts to the set temperature of the hot water outlet temperature setting device. A temperature sensor is provided on the downstream side of the heat exchanger in the hot water path and the confluence path, and a burner that heats the heat exchanger is detected by the temperature sensor in the hot water path. Based on the hot water temperature and the set temperature, the hot water temperature is controlled to be a predetermined temperature higher than the set temperature, and the set temperature is maintained based on the hot water temperature detected by the temperature sensor in the merging channel. A hot water supply mechanism for an instantaneous water heater, characterized in that it is configured to perform feedback control on the