JPH0239167Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of instantaneous water heaters, and relates to the improvement of instantaneous water heaters. A temperature control valve having a through hole to the heat exchanger and a through hole to the bypass path is provided in a branch path of a bypass path that branches from the water supply path and communicates with the hot water outlet pipe, and A thermistor installed on the side for detecting hot water temperature and a fuel regulating valve provided in the fuel supply path are connected to a drive device for the throttle shaft of the temperature regulating valve through a controller, and the temperature regulating valve is rotationally driven at the initial stage of hot water discharging. Flow approximately the same small amount of water through the heat exchanger and the bypass path,
After a certain period of time (for example, several seconds) has elapsed, the temperature control valve is rotated to stop the water supply to the bypass path,
From then on, the water supplied only to the heat exchanger will be increased sequentially to a predetermined amount of water, and the after-boiling phenomenon of instantaneous water heaters (in the case of intermittent use of instantaneous water heaters that repeatedly start and stop hot water, the retained heat after combustion of the burner stops) will be avoided. is transferred to the endothermic part of the heat exchanger, excessively heating and raising the temperature of the residual water, causing abnormally high temperature hot water to be discharged at the beginning of hot water discharging), and pre-cooling phenomenon (the abnormally high temperature hot water is discharged at the beginning of hot water taping). Immediately after the cold water is discharged, until the heat exchanger reaches the required temperature and stabilizes, the cold water is barely heated and then flows out at a low temperature close to that of cold water, resulting in a sudden and abnormal drop in the outlet temperature. ). However, in this case, even if the amount of hot water dispensed, that is, the amount of water flowing through the water supply channel, is different, the passage to the bypass path of the temperature control valve is closed after a certain period of time (several seconds) has elapsed after hot water is dispensed, so the amount of water flowing through the water supply channel is When the flow rate is high, for example 10/min, the superheated water remaining in the heat exchanger flows out for a few seconds, during which time the necessary cold water is supplied to the bypass path, and the superheated water is mixed with cold water to prevent the after-boiling phenomenon. However, when the flow rate is low, e.g. 2/min, the superheated water will take a long time to flow out, and the mixing time will be longer than the above 10 minutes.
Since cold water cannot be supplied to the bypass path for the necessary time in the same number of seconds as in the case of /minute, superheated water remains and the after-boiling phenomenon cannot be sufficiently prevented, resulting in superheated water coming out. In addition, in order to prevent the after-boiling phenomenon when the flow rate of water in the water supply channel is low, the time required to close the passage to the bypass path of the temperature control valve is increased to, for example, 10 seconds, so that when the flow rate is low, cold water can flow to the bypass path for the required time. However, when the amount of water flowing is large, the mixing time becomes longer than necessary, resulting in a pre-cooling phenomenon.

This idea improves on this point by installing a temperature control valve in the water supply channel to open and close the flow of water to the bypass path and the heat exchanger, and a flow rate sensor to detect the flow rate in the water supply channel, which is controlled by a controller. The temperature control valve is linked to the drive device for the throttle shaft of the temperature control valve, and the opening and closing times of the through hole of the temperature control valve to the bypass path are changed according to the amount of water flowing in the water supply channel, and cold water is supplied from the bypass path to the hot water outlet pipe. The present invention relates to an instantaneous water heater which can prevent the after-boiling phenomenon in any water flow rate range by changing the mixing time, and also prevents the pre-cooling phenomenon from occurring.

This invention will be explained below based on embodiments shown in the drawings.

A is a fin-and-tube type heat exchanger, which is equipped with a thermistor T near the outlet of the heat exchanger A to detect the hot water temperature, and has a water supply pipe 1a on the inlet side of the heat exchanger A and a hot water outlet on the outlet side. Connect the tubes 2 respectively. Reference numeral B designates a gas burner for heating the heat exchanger A, and gas is supplied to the gas burner B through a fuel regulating valve _V1 provided in the gas supply path 3, with the amount thereof being regulated. V ₂ is installed in a branch path between a bypass passage 4 communicating from the water supply pipe 1 to the outlet pipe 2 and a water supply pipe 1a to the heat exchanger A,
The temperature control valve is equipped with a bypass passage 4 and a through hole to the water supply pipe 1a, and the throttle shaft of the temperature control valve is rotationally driven by a drive device M such as a motor to adjust the amount of water supplied to the heat exchanger A. The amount of water supplied to the bypass path 4 is adjusted. The drive unit M rotates the aperture shaft to adjust opening and closing.
Immediately after hot water is tapped, a small amount of water is flowed to both the heat exchanger A and the bypass path 4, and the bypass path ₄ of the temperature control valve V2 is passed after a necessary period of time according to the flow rate signal generated by the flow rate sensor E, which will be described later. The water supply to the bypass passage 4 is stopped by closing the through hole to the heat exchanger A, and a predetermined amount of water is supplied only to the heat exchanger A.

A flow rate sensor E for detecting the amount of water flowing is provided at a suitable location in the water supply channel 1 on the upstream side of the temperature control valve _V2 , and the flow rate sensor E is connected to the drive device M via the controller C. The throttle shaft of _{No. 2} is made proportional to the water flow rate of the water supply channel 1 and the rotation speed of the drive device M, so that when the flow rate is large, the rotation speed is controlled quickly, and when the flow rate is low, the rotation is controlled slowly. The time taken to close the hole leading to the bypass path 4 of the temperature control valve _V2 immediately after is changed, and the time for mixing from the bypass path 4 to the outlet pipe 2 is adjusted to be longer or shorter depending on the flow rate. The inverse proportionality coefficient between the water flow rate and the mixing time when the mixing time is shortened when the flow rate is high and the mixing time is long when the flow rate is low is set to an appropriate value depending on the temperature gradient, length, inner diameter, etc. of the heat absorption tube of heat exchanger A. It is determined. In the example, water supply channel 1
A governor valve 6 is provided on the upstream side of the temperature control valve _V2 , an automatic flow rate adjustment device D is provided to keep the water supply pressure on the secondary side always at a constant value, and a flow rate sensor E is provided at the inlet port 5. .

In addition, 7 is a connecting pipe that communicates the negative pressure side of the automatic flow rate regulator D with the ventilary section 8 provided in the water supply pipe 1a, F is a hot water outlet temperature setting device, and _V3 is a connecting pipe for connecting the fuel regulating valve _V1 to the gas supply pipe 3. This is a solenoid valve placed on the upstream side.
The automatic flow rate adjustment device D does not necessarily need to be installed. In addition, a thermistor T for detecting the hot water temperature, a fuel regulating valve V ₁ , a flow rate sensor E, a driving device M, a hot water tap temperature setting device F, etc. are connected to the controller C so that they are related to each other, and the hot water temperature detecting device is connected via the controller C. The opening degree of the fuel regulating valve _V1 is adjusted based on the sensing signal of the thermistor T and the water flow rate signal, so that the set hot water temperature can be controlled. Here, the fuel adjustment valve V ₁ corresponds to the flow rate Q detected by the flow rate sensor E,
Temperature difference T _{1 −T 0 between} the detected temperature T 1 of the thermistor T for detecting hot water temperature and the set temperature T ₀ of the hot water temperature setting device E
By multiplying by the calculated value, the opening degree is determined to be proportional to the calculated value, and the water supply is heated with the required heating capacity.

Since this device has the above-mentioned configuration, at the initial stage of hot water dispensing, the hole to the bypass path 4 of the regulating valve V ₂ is in communication with the bypass path 4, and the hole to the heat exchanger A is in communication with the water supply pipe 1a of the heat exchanger A. As a result, approximately the same amount of cold water is flowed into both the water supply pipe 1a of the heat exchanger A and the bypass path 4. A flow rate sensor E detects the flow rate of water in the water supply channel 1 immediately after hot water is discharged, and the flow rate signal is sent to a drive device M via a controller C.
The rotation speed of the throttle shaft of the temperature control valve _V2 is adjusted and controlled by changing the output of the temperature control valve V2. In other words, the output (voltage) of the drive device M is changed via the controller C according to the flow rate detected by the flow rate sensor E, and the throttle shaft of the temperature control valve _V2 is adjusted earlier when the flow rate is high and when the flow rate is low. By controlling the rotation slowly, the bypass passage 4 is supplied with just the right amount of cold water. The after-boiling phenomenon is appropriately prevented by mixing cold water and lowering the discharged boiling water to an appropriate temperature. Immediately after hot water is released, the flow rate sensor E in the water supply channel 1 indicates a flow rate of 10, for example.
/minute is detected, the time required to close the hole of the temperature control valve V ₂ to the bypass path 4 immediately after hot water is released is, for example, about 2 seconds, and the necessary cold water can be supplied to the bypass path 4.
For example, when detecting a flow rate of 2/min, the time until the hole in the bypass passage 4 is closed immediately after hot water is tapped is increased, for example, to about 10 seconds, and the necessary cold water is transferred to the bypass passage 4.
By mixing the amount of cold water necessary for the outflow of high-temperature boiling water in the heat absorption tube section or outlet pipe of the heat exchanger A, it is possible to eliminate the outflow of high-temperature boiling water, that is, the after-boiling phenomenon.

After tapping the hot water, the temperature control valve V ₂ is rotated quickly or slowly according to the flow rate detected by the flow rate sensor E to close the hole in the rear bypass path 4, stop the water supply to the bypass path 4, and then Normal hot water supply is performed by supplying water at a predetermined flow rate only to the boiler.

At the same time, a predetermined flow rate of water in the water supply pipe 1 is detected by a flow rate sensor E, and based on the output signal, a solenoid valve V ₃ is opened, gas is supplied to a gas burner B through a fuel adjustment valve V ₁ , and the gas burner B ignites and burns. Heat exchanger A
is heated and the temperature is gradually raised to a predetermined temperature and stabilized. At this point, the opening degree of the fuel regulating valve V ₁ is adjusted in proportion to the product of the flow rate of water flowing through the water supply pipe 1 and the temperature difference between the set temperature and the outlet temperature. Heating is performed with a heating capacity commensurate with the amount of water flowing, and the hot water temperature is controlled to the set temperature. When this heating capacity is exceeded, the degree of opening of the through hole of the temperature control valve _V2 to the water supply pipe 1a is reduced to maintain the heating capacity range of the gas burner B, thereby preventing the capacity from being exceeded. In this way, it is possible to eliminate the pre-chilling phenomenon due to overcapacity immediately after hot water is tapped.

When the hot water supply is stopped, the temperature control valve _V2 is rotated in the opposite direction to return it to its original state, and the bypass path returns to the state where it communicates with the water supply pipe and the hot water supply pipe, and is ready for the next hot water supply. Furthermore, when the water heater is stopped, the water supply pipe 1a, the hot water outlet pipe 2, and the bypass path 4 are in a closed loop, so that by heating the bypass path 4 with an appropriate means, the water accumulated in the water pipe can be circulated and heated. This can also be used to prevent water heaters from freezing during the winter.

According to the instantaneous water heater of this invention described above, the flow rate sensor installed in the water supply channel detects the flow rate of water immediately after hot water is released, and the temperature control valve installed in the water supply channel is activated according to the flow rate. By changing the output of the drive device and adjusting the length of time until the bypass path of the temperature control valve is closed, the required amount of cold water can be constantly supplied to the bypass path, which prevents the after-boiling phenomenon and prevents unnecessary mixing. Since there is no pre-chilling phenomenon, the temperature of the hot water is stable
It improves its reliability and is safe and useful in actual use.

[Brief explanation of drawings]

The drawing is a schematic diagram showing an embodiment of this invention. A...Heat exchanger, T...Thermistor for detecting hot water temperature, _V1 ...Fuel adjustment valve, _V2 ...Temperature control valve, C...
... Controller, E ... Flow rate sensor, 1 ... Water supply pipe, 2 ... Hot water outlet pipe, 3 ... Gas supply path, 4 ...
bypass road.

Claims (1)

[Scope of utility model registration request] A thermistor T for detecting hot water temperature provided near the outlet of the heat exchanger A, a fuel regulating valve _V1 provided in the fuel supply path of the gas burner B, a water supply waterway, and a bypass passage 4 that branches from the water supply waterway and communicates with the hot water exit pipe 2. A drive device M that drives the throttle shaft of the temperature control valve _V2 having a through hole to the
is connected via a controller C, a flow rate sensor E for detecting the flow rate is arranged at an appropriate location in the water supply channel, and this is connected to the drive device M via the controller C, and the temperature control valve V is connected immediately after hot water is tapped. ₂
The instant hot water boiler is configured such that the temperature of the hot water at the outlet can be adjusted by changing the driving speed of the throttle shaft in proportion to the flow rate and changing the time for mixing cold water from the bypass passage 4 immediately after hot water is discharged in accordance with the flow rate. vessel.