JPH029263B2 - - Google Patents

Description

[Detailed description of the invention] This invention is based on the after-boiling phenomenon (a phenomenon in which residual water is heated to an abnormally high temperature due to the retained heat after combustion stops when the burner is used intermittently and becomes abnormally high-temperature water, and the high-temperature water is discharged when hot water is tapped). It prevents the cooling phenomenon (immediately after high-temperature water is discharged when hot water is discharged, the heat exchanger hardly raises the temperature until it reaches the required temperature and stabilizes, and the water flows out in a state close to cold water), and the burner can be heated by adjusting the water flow rate. Regarding an effective instantaneous water heater that enables highly accurate temperature control that accurately corrects excess heating capacity of It is equipped with a regulating valve and a second flow rate regulating valve, and has a configuration such as via a ventilly to adjust the amount of water flowing to the heat exchanger, and a bypass channel that opens and closes a branching path that branches from the downstream side of the ventilary, leading from the branching channel to the hot water outlet pipe. The first flow regulating valve and the second flow regulating valve are set in an open state at a starting position by a drive device that drives and operates the first flow regulating valve and the second flow regulating valve. In preparation for water supply, a small amount can be distributed to the heat exchanger and bypass path at the beginning of hot water supply, and after a certain period of time, the second flow rate adjustment valve in the branch path is closed, and the first flow rate adjustment valve is set to a predetermined maximum. The opening of the first flow rate regulating valve can be adjusted to the desired opening so that the maximum heating capacity of the water heater can be obtained, and when the heating capacity of the burner is exceeded, the first flow rate regulating valve can be adjusted to the opening of the desired opening in order to control the hot water temperature to the set temperature. To provide an instantaneous water heater which can reliably prevent post-boiling phenomena and pre-cooling phenomena, correct over-capacity states, and stabilize the outlet temperature.

The present invention will be described below based on embodiments shown in the drawings.

1 to 3 show the case where the present invention is applied to an instantaneous gas water heater. A is a fin-and-tube type heat exchanger, in which a valve chamber 2 is connected to the outflow side of a water supply pressure automatic adjustment device D provided in a water supply channel 1 to the heat exchanger, and an automatic vent 3 is connected to the valve chamber 2. At the same time, the branch passage 4 provided on the downstream side of the ventilate 3 is opened to the valve chamber 2, and the outlet pipe 5 is opened to the valve chamber 2.
The bypass passage 6 leading to the valve chamber 2 is opened, and the valve chamber 2 is opened.
The valve 7 is provided with a first flow regulating valve V ₁ (to be described later) that adjusts the opening degree on the inflow side of the ventilate 3 and a second flow regulating valve V ₂ (to be described later) that adjusts the opening degree of the bypass passage 6. , one end of the pot 7 is connected to a drive shaft 8 of a servo motor M, and a cam plate 9 connected to rotate together with the drive shaft 8 determines the starting position of the pot 7 and the maximum opening of the first flow rate regulating valve _V1. two switches S ₁ and S ₂ at the position and minimum opening position.
This is an instantaneous gas water heater that operates ON and OFF and detects the difference in the combined signal of ON and OFF states to detect each position. In the example, the water supply pressure automatic adjustment device D is a diaphragm type, and a governor type 1 is used.
Acts on the pressure of flowing water entering from the water inlet 11 through 0,
Turn on the water flow switch S via the diaphragm,
Turn it off. The automatic ventilator 3 has a structure in which the valve body 12 is biased in the closing direction by a spring 13, and when the flow rate is small, the throttle becomes large, and when the flow rate is large, the throttle becomes small.

At the front of the pot 7, there is a circular hole 14 forming a first flow rate regulating valve V ₁ to obtain the maximum amount of water flowing in the circumferential direction, and a tapered hole 1 that gradually narrows down to the minimum amount of water flowing.
5 in series, and a second flow rate adjustment valve at the rear.
A notch 16 with a semicircular cross section is provided to form the V ₂ and open/close the branch path 4, and the rear end of the cutout 7 is connected to the drive shaft 8 of the servo motor M. The device is equipped with a cam plate 9, and the cam plate 9 is associated with limit switches S ₁ and S ₂ provided oppositely above and below the container body 17, and turns ON and OFF respectively. That is, limit switches S ₁ and S ₂ are activated by the cam plate 9 at the starting position.
Both are turned on, and the second flow rate regulating valve _V2 is opened (as shown in Fig. 3 _a1 and _a2 ). Water flow switch S turns on and gas burner B heats heat exchanger A.
When igniting, the servo motor M is rotated for a certain period of time (for example, 5 seconds) until the limit switch S ₂ turns OFF, and the limit switches S ₁ and S ₂ are turned off.
ON and OFF, and by detecting the state, it is stopped at that position, and at the stopped position, the notch 16 of the second flow regulating valve V ₂ is closed, and the circular hole 14 of the first flow regulating valve V ₁ is open at the center. (shown in Figure 3 b ₁ and b ₂ ). Then, the opening degree of a fuel regulating valve _V3 , which will be described later, is varied to control the outlet hot water temperature to a set temperature. Therefore, if the heating capacity of the gas burner B is exceeded and the hot water temperature does not reach the set temperature, the servo motor M is rotated in the forward direction, and the taper hole 15 is gradually narrowed from the maximum flow circular hole 14 of the first flow rate regulating valve _V1 . is opened, stopped at the required opening position, and supplied to the heat exchanger with a flow rate suitable for the set temperature.Furthermore, if the heating capacity of gas burner B is exceeded, servo motor M is further rotated, and finally Limit switch S ₁ is OFF, limit switch S ₂ is ON
The terminal end of the tapered hole 15 opens and the minimum opening degree of the first flow rate regulating valve _V1 is reached (the third
(shown in Figures c ₁ and c ₂ ). That is, when the capacity is exceeded, the servo motor M is rotated in a direction to reduce the amount of water, and the temperature is raised to a set temperature range, thereby controlling the outlet temperature to the set temperature.

In addition, the above starting position, maximum water flow position and minimum water flow position to heat exchanger A are set using two limit switches.
Although detection was performed in different combinations of ON and OFF of S ₁ and S ₂ , three limit switches may also be used.

Figure 4 shows the flow rate at the starting position, maximum opening position, and minimum opening position of the flow regulating valve at the solid line point Qa,
The flow rate of the first flow rate regulating valve and the flow rate of the second flow rate regulating valve are indicated by Qv ₁ and Qv ₂ of broken lines. That is, the flow rate is gradually increased from the state where it is throttled at the starting position, and the first flow rate regulating valve V ₁ is fully opened to reach the maximum flow rate (at this point, Qv ₂ is 0).
Thereafter, the first flow rate regulating valve _V1 is gradually throttled down to reduce the water flow to the minimum flow rate. Further, the servo motor M, a thermistor T provided near the outlet of the heat exchanger A to detect the hot water temperature, and a gas supply pipe 18 to the gas burner B that heats the heat exchanger A.
The fuel regulating valve V ₃ installed in the hot water outlet temperature setting device E is connected via the controller C, and the controller C adjusts the temperature in proportion to the temperature difference between the set temperature set by the hot water temperature setting device E and the hot water temperature. The amount of gas supplied to gas burner B is adjusted by adjusting the opening degree of fuel adjustment valve V ₃ , and when the amount of water flowing exceeds the heating capacity of burner B [flowing water amount x (set temperature - hot water temperature)] As described above, the controller C rotates the servo motor M so that the first flow valve V ₁ has an opening between the maximum opening and the minimum opening, and the required water flow rate is determined by rotating the knob. The temperature is controlled within the temperature range of ±2°C as described below. That is, in FIG. 5, the voltage applied to the servo motor M is changed stepwise according to the temperature difference (output temperature - set temperature), and the rotational speed of the servo motor M is changed stepwise within a range of ±2°C. 0, the servo motor M is stopped, and then the fuel adjustment valve _V3 is adjusted to the required opening degree to adjust the calorific value of the gas burner B to the required amount, thereby enabling automatic control. In addition, 19 is a communicating hole that communicates the negative pressure side of the automatic water supply pressure adjustment device D with the automatic ventilator 3, and 20 is a return spring of the diaphragm.

With the above configuration, when the instantaneous gas water heater is repeatedly used intermittently, the first flow rate regulating valve _V1 is slightly throttled to a constant opening at the starting position of the pot 7, as shown in Figure _3a2 . In addition, the second flow rate adjustment valve V ₂ is set at a constant opening degree that is almost the same as the first flow rate adjustment valve V ₁ , and from the time when the water flow switch S is activated by the flow water pressure at the beginning of hot water dispensing, there is a certain period of time for pre-purge etc. For example, for 5 seconds), a small amount of cold water of approximately the same amount is flowed from the automatic ventilator 3 to the heat exchanger A and the bypass path ₆ via the first flow rate regulating valve V ₁ and the second flow rate regulating valve V 2. The boiling water that has reached a high temperature due to the after-boiling phenomenon is mixed in the middle of the outlet pipe 5, and the temperature of the boiling water etc. discharged from the heat exchanger A is lowered to an appropriate temperature, thereby appropriately preventing the after-boiling phenomenon.
Here, approximately 2/min of water flows into the heat exchanger A and the bypass path 4, respectively, and the residual water in the heat exchanger A when the water is stopped after hot water supply is superheated and its temperature reaches, for example, 70°C. Moreover, assuming that the incoming water temperature is 25°C, the temperature of hot water exiting from the hot water outlet pipe 5 decreases to 70°C x 2 + 25°C x 2/4 = 47.5°C. Moreover, at the beginning of hot water dispensing, during a certain period of time such as pre-barge, only approximately 4/min of water flows, and the amount of water flowing into the heat exchanger and the amount of water flowing to the bypass path are approximately 1/2, and the amount of water flowing to the heat exchanger is approximately 2/min. /min, the water flow rate in the heat exchanger A becomes considerably slow, and the passing time becomes long, so that the temperature of the cold water can be sufficiently raised, and the pre-cooling phenomenon can be eliminated. When the water flow switch S is activated and the gas burner B is ignited after a certain period of time in the initial stage of hot water dispensing, the cam plate 9 is rotated by the rotational drive of the servo motor M, and the limit switch S ₁ is ON and the limit switch S ₂ is turned on.
Detects that the servo motor M has turned OFF, stops the servo motor M at that position, sets the first flow rate adjustment valve _V1 to the maximum opening, closes the second flow rate adjustment valve _V2 , and supplies the predetermined maximum flow rate to the heat exchanger A. After water is passed through, normal hot water supply begins (see b ₁ and b ₂ in Figure 3 and point Qb in Figure 4). If the amount of water flowing through the heat exchanger A exceeds the heating capacity of the gas burner B, the set hot water temperature cannot be obtained, so the servo motor M is rotated in the forward direction and the first flow rate regulating valve is turned on.
Reduce the flow rate of _V1 and stop at the required water flow rate position as described above. For example, the inlet water temperature is 10℃, the set water outlet temperature is 50℃, and the maximum heating capacity of burner B is
Assuming 400Kcal/min, the flow rate obtained is: 400Kcal/min/50℃-10℃=400×℃/min/40℃=10
/min, and the flow rate is set to 10 at an appropriate position of the taper hole 15 to obtain a hot water temperature of 50°C. As mentioned above, the servo motor M is rotated forward and backward until the temperature difference between the outlet hot water temperature and the set temperature is, for example, within the range of ±2°C. After the temperature difference reaches ±2°C, only the fuel regulating valve _V3 is adjusted to the above temperature range. The opening degree is adjusted in proportion to the temperature to accurately and stably control the hot water temperature. The above temperature difference is ±2℃
As the size increases, the rotational speed of the servo motor M is increased to increase the adjustment speed of the water flow rate of the heat exchanger, thereby eliminating delay in response speed. Here, it is of course possible to control the outlet temperature to the set temperature as the required flow rate only by rotating the pot 7 by the servo motor M. Furthermore, if the heating capacity of the gas burner B is exceeded, the servo motor M is further rotated to drive the limit switches S ₁ and S ₂ until they are turned OFF and ON, respectively, and then stopped.
V ₁ is set to the minimum opening degree to allow the minimum amount of water to flow into heat exchanger A (see c ₁ and c ₂ in Figure 3 and point Qc in Figure 4). As is clear from the above description, the water flow switch S is activated by the hot water discharge, and after the above-mentioned certain period of time has elapsed, gas is supplied to the gas burner B through the fuel adjustment valve _V3 , the gas burner B ignites, burns at full input, and performs heat exchange. Heater A is heated and the temperature is gradually raised to a constant temperature and stabilized, but during that time the flow rate of heat exchanger A is gradually increased, so heating is performed with a heating capacity commensurate with the flow rate, and at first it remains at a constant temperature for a certain period of time. Since the amount of water flowing into the heat exchanger is small, the temperature of the hot water does not drop drastically and the pre-chilling phenomenon can be prevented. When you stop participating, the servo motor M
rotates in the opposite direction and limit switches S ₁ and S ₂ are both turned on.
When this is detected, the servo motor M stops and returns to the original starting position (Fig. 3 a ₁ , a ₂ and Fig. 4).
(See point Qa) 1st flow regulating valve V ₁ and 2nd flow regulating valve
Return V ₂ to the starting position to prepare for the next tap. The degree of opening (cross-sectional area) of the circular hole 14 that regulates the predetermined minimum amount of water in the heat exchanger A at the initial stage of hot water tapping is the same as that of the heat exchanger A.
Depending on the inner diameter and length of the heat absorption pipe, the pre-purge time, etc., the heat capacity of heat exchanger A, etc., appropriate measures should be taken to ensure that the supplied water does not leave heat exchanger A as cold water or in an extremely low temperature state. Determine the size. Furthermore, although the case where the cock 7 is rotated by a servo motor is illustrated, it may be moved forward and backward, and in that case, it is necessary to form the circular hole 14 and the tapered hole 15 to extend continuously in the axial direction. it is obvious.

As described above, in the water heater according to the present invention, the above-mentioned holding control for a certain period of time, control of water supply amount by rotating operation of the pot 7, etc. are performed appropriately according to a preset program by the controller C. The hot water temperature and the amount of hot water are also adjusted via the controller C, and the taper hole 15 of the tap 7 and the opening degree of the fuel regulating valve _V3 are adjusted and controlled by the thermistor T for detecting the hot water temperature. By adjusting and controlling the opening degree of the first flow rate regulating valve _V1 to a required value within the heating capacity range of the heat exchanger A, it is possible to automatically control the outlet hot water temperature to the set outlet temperature. .

According to the instantaneous water heater of the present invention, when the hot water supply is stopped, the bypass pipe 6 and the water supply pipe 1 to the heat exchanger A are connected to each other.
and hot water outlet pipe 5 from heat exchanger A are connected in a closed loop through the second flow rate adjustment valve V ₂ , so if the bypass pipe 6 is heated with an electric heater etc. in severe cold, the residual water in the vessel will be heated. Since it is circulated and can heat most of the water pipes, it has the effect of effectively preventing freezing.

The case where the water supply amount (hot water output amount) characteristic has a chevron shape has been described above, but as shown in Fig. 6, the graph of the flow rate characteristic has an upward slope in the right half, and the rotation end of the first flow rate control valve V ₁ is shown. The first flow regulating valve V ₁ is rotated in the opposite direction from the maximum opening position to the minimum opening position (indicated by the water flow rate Qc point), and this angle is Qv ₂ is O.). In this case, the hole 7 needs to have a circumferentially extending through hole 21 whose opening degree gradually changes from small to large (see FIG. 7). Further, although the case has been described in which the first flow rate regulating valve V ₁ and the second flow rate regulating valve V ₂ are integrally molded, they may be formed as separate bodies and driven (rotated) synchronously.

According to the above-mentioned invention, a flow rate regulating valve for regulating the amount of water flowing to the heat exchanger and the bypass passage is disposed in the water supply channel, and a switch is connected to the cam plate provided on the drive shaft to adjust the flow rate. starting position of the valve,
The position of the maximum water flow to the heat exchanger and the position of the minimum water flow can be determined.In the initial stage of hot water dispensing, a small amount of water is diverted to the heat exchanger and the bypass path for a certain period of time (several seconds) through the flow rate adjustment valve, and then the heat By setting the appropriate amount of water to the exchanger, the after-boiling phenomenon and pre-cooling phenomenon can be reliably prevented with a simple configuration, and when the capacity is exceeded, the flow rate adjustment valve can be appropriately throttled to maintain the required water flow rate. By adjusting the temperature, it is possible to correct the unintentional drop in the hot water temperature due to overcapacity as in the past, and to control the hot water temperature accurately, quickly, and with high precision, and to stabilize the hot water temperature.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of this invention, Fig. 2 is a perspective view showing an embodiment of the same flow regulating valve (Kotoku), and Fig. 3 shows the rotation (stop) angle of the flow regulating valve. Explanatory diagram showing the opening degree of the flow rate adjustment valve, No. 4
The figure is a graph showing the flow rate (output amount) characteristics of the same flow rate adjustment valve, Figure 5 is a graph showing the outline of the applied voltage characteristics of the servo motor, and Figure 6 is a graph showing the flow rate (output amount) of another flow rate adjustment valve. Graph showing the characteristics, Figure 7 is the 6th
It is a perspective view which shows one Example of the flow regulating valve in a figure. DESCRIPTION OF SYMBOLS 1... Water supply channel, 2... Valve chamber, 3... Automatic ventilate, 4... Branch path, 5... Hot water outlet pipe, 6... Bypass path, 7... Kotoku, 8... Drive shaft, 9...
Cam plate, A...heat exchanger, _V1 ...first flow rate regulating valve, _V2 ...second flow rate regulating valve, M...servo motor.

Claims (1)

[Claims] 1. A water supply pipe to the heat exchanger is provided with a first flow rate adjustment valve for adjusting the amount of water flowing to the heat exchanger, and a bypass pipe connected from the water supply pipe to a hot water outlet pipe is provided. Equipped with a second flow rate adjustment valve that supplies and disconnects water flow to the hot water tap pipe,
A drive device is provided to drive the first and second flow rate regulating valves in conjunction with each other, and the drive device includes a hot water temperature detector installed in a hot water tap near the outlet of the heat exchanger, and a fuel installed in the fuel supply path of the gas burner. The regulating valve and hot water temperature setting device are connected via a controller, and the first and second flow rate valves are driven by a drive device to maintain a constant opening for a predetermined time at the start of hot water tap to exchange heat in small amounts of flowing water. After a predetermined time, the second flow rate adjustment valve is closed, and the first flow rate adjustment valve is set to the maximum opening to maximize the amount of hot water flowing into the heat exchanger, and the burner is An instantaneous water heater characterized in that if the heating capacity is outside the range, the hot water temperature can be controlled to a set hot water temperature by adjusting the opening degree to a required degree. 2. In adjusting the opening degree of the first flow rate regulating valve after a predetermined period of time after the start of hot water dispensing, a servo motor that drives the regulating valve is operated according to the temperature difference between the discharging hot water temperature detected by the dispensing hot water temperature sensor and the discharging hot water temperature set by the dispensing hot water temperature setting device. 2. The instantaneous water heater according to claim 1, wherein the driving speed of the flow rate regulating valve is increased as the temperature difference increases by varying the applied voltage.