JPH0532957U - Electric water heater - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an electric water heater having a structure in which a hot water storage tank and a heating unit are separated, and in which maintenance of the hot water storage tank is unnecessary. [Structure] A pressure sensor and a temperature sensor for respectively detecting water pressure and water temperature on the suction port side of the pump of the heating unit are arranged, and the control unit determines the water level of the hot water storage tank from the pressure detected by the pressure sensor. The water temperature of the hot water storage tank is detected by guiding a part of the hot water in the hot water storage tank to a temperature sensor by a pump. With this configuration, it is not necessary to arrange sensors in the hot water storage tank, and the intended purpose can be achieved.

Description

[Detailed description of the device]

[0001]

[Field of Industrial Application] The present invention relates to an electric water heater used in a general house or the like.

[0002]

2. Description of the Related Art An electric water heater has a structure in which water stored in a hot water storage tank is heated by an electric heater arranged in the tank, and the natural convection caused by this heating causes the entire water in the hot water storage tank to boil. Things are common. However, electric water heaters with a general structure have the drawback that the installation space is quite large, and it is becoming difficult to install them in houses with small spaces due to rising land prices. Therefore, recently, the hot water storage tank and the heating section are separated, and the hot water storage tank is placed in a dead space such as under the floor to save the space for the electric water heater.

[0003]

[Problems to be Solved by the Invention] In a hot water storage tank, a sensor for detecting the water level and water temperature in the tank is usually arranged at an appropriate position, and the hot water storage tank is installed in a dead space such as under the floor. In this case, due to the maintenance of these sensors, the degree of freedom of the installation location is small, and it is necessary to provide an inspection port on the floor. Further, there is a problem that it becomes difficult to perform maintenance of the sensors.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric water heater that does not require maintenance of a hot water storage tank.

[0005]

Means for Solving the Problems A structure for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. The present invention goes to a hot water storage tank 1 and an inside of the tank 1. An electric heater 20 that communicates with the return pipes 11 and 12, and a heating unit 2 that has a pump 23 that is connected to the outgoing pipe 11 and that has a discharge port that communicates with the inside of the electric heater 20 through a check valve 26; The control unit 3 for controlling the driving of the heater 20 and the pump 23 is provided, and by these controls, the hot water from the electric heater 20 is guided to the hot water storage tank 1 and the hot water of the set volume is stored in the tank 1. In the water heater, a pressure sensor 24 and a temperature sensor 25 for detecting the water pressure and the water temperature on the suction port side of the pump 23 are arranged in the heating unit 2, and these two sensors 24 It is characterized in that the control unit 3 is configured to perform the above control based on the output of 5.

[0006]

The water level in the hot water storage tank 1 can be detected by the pressure sensor 24. The principle will be described with reference to FIG. First, the case where the hot water storage tank 1 is located above the pump 23 (a) and the pump 23 is in the OFF state will be described. When the pressure acting on the pressure sensor 24 when the water level of the hot water storage tank 1 is at the lower limit water level is P ₁ and the pressure at an arbitrary water level is P _X , (P _X −P ₁ ) You can know the water level. That is, at the time of initial water passage to the hot water storage tank 1, the detection value P ₁ of the pressure sensor 24 at the time when the water level reaches the lower limit water surface of the tank 1 is stored in the control unit 3, and thereafter, the pump 23 The water level in the hot water tank 1 can be obtained by calculating the difference between the detected value P _X by the pressure sensor 24 and the stored value P _{1 in the} stopped state by the control unit 3. Since the pressure P ₀ on the heater 20 side is stopped by the check valve 26, the pressure sensor 24 is not affected.

Next, when the water level in the hot water storage tank 1 is at the lower limit water level and the pump 23 is in the ON state, the pressure P _S acting on the pressure sensor 24 becomes (P ₁ −ΔP ₁ ). However, Δ P ₁ is the negative pressure of the pump 23. On the other hand, when the water level in the hot water storage tank 1 is an arbitrary level P _X , the pressure P _t acting on the pressure sensor 24 is (P _X −ΔP ₂ ), and the actual water level is P _t −P _S = (P _X −ΔP ₂ ) − (P ₁ −ΔP ₁ ). Here, since the negative pressure of the pump 23 is ΔP ₁ ≈ΔP ₂ , P _t −P _S = P _X −P ₁ . Therefore, also in this case, when the water level reaches the lower limit water level during the initial water flow to the hot water storage tank 1, the water flow is temporarily stopped and the pump 23 is driven, and the detected value by the pressure sensor 24 in this state. P _S is stored in the control unit 3, and thereafter, the difference between the detected value P _t by the pressure sensor 24 and the stored value P _S when the pump 23 is in a driving state is calculated to calculate the water level in the hot water storage tank 1. Can be asked. However, in this case, in order to avoid transient pressure fluctuation due to rotation / stop of the pump 23, the detection value of the pressure sensor 24 is sampled after the rotation of the pump is stabilized.

Here, when the hot water storage tank 1 is located below the pump 23, the pressures P ₁ and P _X acting on the pressure sensor 24 become negative pressures as shown in FIG. The water level can be calculated by the same arithmetic expression as. On the other hand, the water temperature in the hot water storage tank 1 can be detected by the temperature sensor 25 by pulling a part of it with the pump 23 because the water temperature in the tank 1 is uniform.

[0009]

Embodiment FIG. 1 is a piping system diagram showing a configuration of an embodiment of the present invention. The hot water storage tank 1 is a tank open to the atmosphere, and is arranged in a dead space such as under the floor. The heating unit 2 is composed of a hermetically sealed heating tank 21, a heater 20 having an electric heater 22 arranged inside the tank 21, a pump 23, and the like. The discharge port of the pump 23 communicates with the bottom of the heating tank 21 via a check valve 26, and the suction port is connected with the outflow pipe 11 whose end communicates with the bottom position of the hot water storage tank 1. It In addition, an upper end of the heating tank 21 is connected to a return pipe 12 whose end faces an upper part in the hot water storage tank 1 and which is provided with a flow switch 4 in the middle thereof. When driven, the water in the hot water storage tank 1 can be circulated through the heating tank 21. Further, the heating tank 21 is connected to a water supply pipe 13 which communicates with a bottom position inside thereof and is equipped with an electric valve 27, and the water supply pipe 13 is connected to a water supply device (not shown).

The heating unit 2 is provided with a pressure sensor 24 and a temperature sensor 25 for detecting the water pressure and the water temperature on the suction side of the pump 23, respectively. The output signal of the switch 4 is input to the control device 3. The control device 3 first opens the electric valve 27 during initial water flow. As a result, water is supplied into the heating tank 21 and the hot water storage tank 1. When the water level of the hot water storage tank 1 reaches the lower limit water level by this water supply, a command to collect the reference value is externally supplied to the control device 3. At the time when this command is input, the control device 3 closes the electric valve 27, collects and stores the value detected by the pressure sensor 24, and then when the pump 23 is driven to stabilize the rotation of this pump. After the detection value of the pressure sensor 24 is collected and the detected value is stored separately from the previous pressure detection value, the driving of the pump 23 is stopped.

By the above operation, the above-mentioned reference pressures P ₁ and P _S are stored in the control device 3, and thereafter, the control device 3 determines based on the detection value of the pressure sensor 24. When the pump 23 is OFF, the above (P _X -P ₁ ) calculation is performed, and when the pump 23 is ON (P _t -P _S ) calculation, the water level of the hot water storage tank 1 is calculated. Go on.

Further, the control device 3 controls the opening / closing of the electric valve 27 and the pump 23 and the electric device based on the water level obtained from the value detected by the pressure sensor 24 and the temperature detected by the temperature sensor 25 during the time period of the midnight electricity rate. The heater 22 is drive-controlled to boil a set volume of hot water in the hot water storage tank 1. Further, after the midnight power energization start time (11:00 pm), the pump 23 is driven, and after a certain time (at least the time during which the hot water in the hot water tank 1 is guided to the position where the temperature sensor 25 is arranged) has elapsed When the value detected by the temperature sensor 25 is below the boiling temperature, the electric heater 22 is driven, and when the sensor detected value reaches the boiling temperature, the driving of the electric heater 22 and the pump 23 is stopped. . When the flow switch 4 is turned off regardless of the fact that the pump 23 is being driven, the electric heater 22 and the pump 23 are interlocked with each other.

[0013]

As described above, according to the present invention, since the water level and the water temperature of the hot water storage tank can be detected on the heating unit side, the maintenance of the hot water storage tank is unnecessary. As a result, even if the hot water storage tank is installed in a dead space such as under the floor, the degree of freedom of its installation position is increased and it is not necessary to provide an inspection port for the hot water storage tank. Furthermore, since most of the control equipment can be placed in the heating section, it is possible to omit the wiring of the wires for the sensors and to maintain them easily.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of the present invention.

[Explanation of symbols]

 1 ...- Hot water storage tank 11 ... Outgoing pipe 12 ... Return pipe 2 ... Heating unit 20 ... Heating device 21 ... Heating tank 22 ... Electric heater 23 ··· Pump 24 ··· Pressure sensor 25 ··· Temperature sensor 26 ··· Check valve 27 ··· Electric valve 3 ··· Control device

Claims (1)

[Scope of utility model registration request] 1. A hot water storage tank and the inside of this tank
An electric heater communicating with the return pipe, and a heating unit having a pump connected to the outgoing pipe and having a discharge port communicating with the inside of the electric heater through a check valve; and a drive control of the electric heater and the pump. A water heater provided with a control unit, which controls the hot water from the electric heater into the hot water storage tank to store a set volume of hot water in the tank, wherein the heating unit includes the pump. An electric water heater characterized in that a pressure sensor and a temperature sensor for respectively detecting the water pressure and the water temperature on the suction port side are arranged, and the control section is configured to perform the control based on the outputs of these two sensors.