JPH0820976A - Electric power saving unit for heater preventing water in service pipe from freezing - Google Patents

Abstract

PURPOSE:To improve the efficiency of electric power saving, and to prevent switching noise from occurring as much as possible, which noise is generated when an electric power saving unit is operated. CONSTITUTION:An electric power saving unit is composed of a temperaturedetecting means 2, a controlling means 3 for dividing temperature proportionally and a switching means 4. In a temperature range from an outside air temperature of 3 deg.C, at which an electric current begins to be applied to a heater 6, to an outside air temperature of -9 deg.C, at which the heater 6 is used at a rated power, according to the outside air temperature, the amount of the electric current being enough to be most suitable for the outside air temperature at that time is supplied to the heater 6 and the consumption power of the heater 6 per hour is reduced. Furthermore, switching noise is not generated by the switching means 4 since the electric current is outputted at the time when electric power lines are in zero volt phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power saving unit for a water freezing prevention heater, and reduces the power consumption of the heater per unit time by appropriately controlling an alternating current applied to a band-shaped heater wound around a water pipe. The present invention relates to a device that conserves power by making it.

[0002]

2. Description of the Related Art In cold regions in winter, the water temperature in water pipes is often below freezing, so that water in water pipes often freezes. When the water in the water pipe freezes, the volume of the frozen water increases and damages the water pipe, causing serious damage such as flooding. As one means for preventing such a situation, a flexible strip-shaped heater for preventing water from freezing is wound around the water pipe, and an alternating current is passed through this heater to generate heat, thereby appropriately heating the water pipe to keep it warm. However, there is something that prevents the water in the water pipe from freezing.

In this case, one heater is 100 to several 1
Since it consumes electric power of 00 W / h and generally uses about 5 heaters per house, using a heater throughout the winter requires a very high electricity charge. For this reason, generally, a power saving unit that energizes the heater only at a temperature equal to or lower than a preset outside temperature is also used.

There are various types of power saving units described above. For example, a semiconductor switch that is turned on and off by a temperature sensor is used, and the current flowing through the heater is half-wave rectified to generate a positive-phase or negative-phase half-wave current. It is known to drive a heater. That is, when the temperature sensor detects that the outside air temperature has dropped to 2 to 3 ° C., the heater is energized, but since the current applied to the heater is a half-wave current, it is possible to save about 50% in actual efficiency.

However, in the above-mentioned conventional example, after the heater is energized, it is used with about half the rated power regardless of the outside temperature, so that a sufficient amount of heat generation can be obtained when the outside temperature drops extremely. If not, there is a risk of damaging the water pipe in some cases. In order to solve this, the temperature sensor
A semiconductor switch that turns N-OFF is used to heat the heater with a half-wave current of only positive phase or negative phase up to a certain ambient temperature, and when the temperature falls, the current is switched to full-wave or both positive and negative phase current. There is something that causes heat.

This is because the temperature range in which the semiconductor switch is turned on is set in two stages, a weak freezing temperature range and a strong freezing temperature range, and when the outside air temperature falls to 2-3 ° C. (weak freezing temperature range) by a temperature sensor, for example. The heater is driven with a half-wave current, and the full-wave current is applied to the heater when the outside air temperature drops to -5 ° C or lower (strong freezing temperature range), and the actual efficiency is about 50% in the weak freezing temperature range. With a heater,
The heater is used at rated power in the strong freezing temperature range.

[0007]

However, since the above-mentioned conventional example has a fixed power saving rate, even at the upper limit temperature of the weak freezing temperature range, for example 2-3 ° C., the lower limit temperature of the weak freezing temperature range, for example − Even at 5 ° C., there is a problem that the same amount of electric power is supplied to the heater, and a sufficient power saving effect cannot be expected. In addition, since the output of the power saving unit in the weak freezing temperature range is a half-wave current, the heating speed of the heater is slow, which is an obstacle to the improvement of the power saving rate.

By the way, since a relatively large current flows through the heater, which is the load of the power saving unit, a very high level of switching noise is generated every time the heater operates and outputs the current supplied to the heater. This noise imposes a burden on each component of the power saving unit itself, shortens its life, and may cause a reception failure in a nearby television receiver or radio receiver. Further, if this noise is placed on the power supply line, it may cause inconvenience such as malfunction of various electronic application devices on the same line.

As described above, the heater for preventing water from freezing is used throughout the winter, and the improvement in the power saving rate is largely reflected in the electricity bill borne, so that the power saving unit with higher power saving efficiency and less switching noise is used. Development was desired. The present invention has been developed in view of the problems of the conventional example as described above, and an object of the present invention is to improve power saving efficiency and to minimize the occurrence of switching noise when the power saving unit operates. An object of the present invention is to provide a power saving unit for a suppressed water freezing prevention heater.

[0010]

In order to achieve the above object, the power consumption of the heater is reduced by connecting to a heater for preventing freezing of water, which is wound around a water pipe, and controlling an AC power supply supplied to this heater. In the power saving unit to be reduced, a configuration is adopted in which the voltage of the AC power supply supplied to the heater and the energization time are controlled according to changes in the outside air temperature.

In this case, temperature detecting means for detecting a change in temperature, temperature proportional frequency dividing control means for controlling the voltage and energizing time of an AC power supply for energizing the heater based on the output of the temperature detecting means, and to the heater When the switching means is 100% output, either full-wave current or positive / negative phase current output current is supplied to the heater to use the heater at rated output. Is less than 100%, the output current that is a combination of half-wave current and full-wave current or both positive and negative phase current is supplied to the heater at appropriate intervals to reduce the power consumption of the heater per unit time. It is preferable to configure so as to reduce.

Specifically, the temperature detecting means in which the first sensor is connected to the first differential amplifier circuit, and the second differential amplifier circuit is connected to the second differential amplifier circuit.
Each output of the temperature-proportional frequency division control means connected to the sensor and the lamp voltage generation circuit is connected to the switching means, and the switching circuit of the switching means is controlled by the pulse of the pulse generation circuit triggered by the 0 volt detection circuit. I am configuring.

In this case, a memory circuit is provided at the output of the first differential amplifier circuit and the pulse generated by the pulse generating circuit is managed every half cycle of the AC power supply frequency, so that the output of the switching means is less than 100%. At this time, it is preferable to supply the heater with an output current obtained by combining a half-wave current with either a full-wave current or both positive and negative phase currents. Also,
By providing a mode switching circuit in the lamp voltage generation circuit and changing the time constant of the lamp voltage generation circuit to an appropriate value, the time interval of the output of the temperature-proportional frequency division control means is changed to consume the heater per unit time. It is preferable to change the power saving rate by changing the power.

[0014]

In the power saving unit for a water anti-freezing heater of the present invention having the above-described structure, the temperature detecting means detects that the outside air temperature has dropped below a certain value, and then energization is started to detect a detection signal from the temperature detecting means. The heater supplies only the alternating current required to generate the amount of heat that does not freeze the water pipe in accordance with the change of the. That is, the power consumption of the heater per unit time is reduced by controlling the voltage of the AC power supply supplied to the heater and the energization time according to the decrease in the outside temperature.

Specifically, when the temperature detecting means detects that the outside air temperature has dropped considerably and the heater must be used at the rated power as before the dawn of the severe cold season, the output of the switching means is 100. %, And the output current of either full-wave current or positive / negative phase current is supplied to the heater.

On the other hand, when the temperature detecting means detects that the outside air temperature is not low enough to use the heater at the rated power, the switching means responds to a change in the detection signal of the temperature detecting means (change in outside air temperature). An output current of 0 to less than 100% is supplied to the heater to reduce the power consumption of the heater per unit time. In this case, the switching means constitutes a so-called zero-cross switch, but a memory circuit is provided at the output of the first differential amplifier circuit to manage the pulse generated by the pulse generating circuit every half cycle of the AC power supply frequency. Therefore, the output of the switching means outputs either a full-wave current or a positive and negative phase current, and a half-wave current is combined as necessary to output the current at the zero point of the alternating current.

As a result, the output current supplied to the heater can be continuously and finely controlled in the temperature range from the outside air temperature at which the heater is energized to the outside air temperature at which the heater is used at the rated power. That is, according to the condition of the outside air temperature, only the amount of current most suitable for the outside air temperature at that time is supplied to the heater to reduce the power consumption of the heater per unit time.

Further, since the switch circuit of the switching means is constructed so as to be turned on and off at the moment when the phase of the AC power source is 0 V, switching noise does not occur when the power saving unit operates, and the power saving unit is not generated. It does not put a burden on itself or cause radio interference or malfunction of various electronic devices.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power saving unit for a water supply antifreezing heater according to the present invention will be described below. FIG. 1 is a block diagram showing an embodiment of the configuration of a power saving unit for a water supply freeze prevention heater according to the present invention. According to this, the power saving unit 1 is composed of the temperature detecting unit 2, the temperature proportional frequency dividing control unit 3 and the switching unit 4, and is connected to the output outlet 1a provided in the housing (not shown) of the power saving unit 1.
It is used by connecting a power plug 7 of a heater 6 for preventing water from freezing, which is wound around a water pipe 5.

Specifically, the temperature detecting means 2 is provided with a first sensor 21 for detecting the outside air temperature in a first differential amplifier circuit 20 which is a comparator, a voltage limiter circuit 22 and a low voltage detecting circuit 23. A reference power supply circuit 24 is provided via the above. Further, the temperature detecting means 2 has a pulse generating circuit 25 for triggering the switching means 4 which will be described later, and the pulse generating circuit 25 has a half wave detecting circuit 26, a 0 volt detecting circuit 27 and a memory circuit 28. Is provided.

In the first sensor 21 of this embodiment, a temperature sensitive element such as a thermistor is assembled in a Wheatstone bridge,
The sensitivity of the sensing element is compensated for and the sampling sensitivity is improved. Other than the thermistor can also be used for this sensing element. The voltage limiter circuit 22 and the low voltage detection circuit 23 are the first differential amplifier circuit 20 due to the voltage drop of the line voltage and external noise.
The reference power supply circuit 24 determines the comparison level of the first differential amplifier circuit 20. In the present embodiment, the energization start temperature to the heater 6 is arbitrarily set by a variable resistor (not shown) or the like provided in the first differential amplifier circuit 20, and is set to, for example, 3 ° C.

The first differential amplifier circuit 20 as a comparator is composed of a general-purpose operational amplifier IC, the half-wave detection circuit 26 is composed of an appropriate rectifying element, and the 0 volt detection circuit 27 is composed of an appropriate gate. Memory circuit 2
Reference numeral 8 is composed of a sample and hold circuit and the like.

The temperature proportional frequency division control means 3 has a second differential amplification circuit 30 and a ramp voltage generation circuit 31, and the second differential amplification circuit 30 has a second differential amplification circuit 30 independently of the above-mentioned temperature detection means 2.
A sensor 32 is provided. The second sensor 32 uses, for example, a thermistor, but other sensing elements can also be used. The ramp voltage generation circuit 31 forms a kind of sweep oscillator together with the period tuning circuit 33 and outputs a sawtooth wave ramp voltage.

In this case, the lamp voltage generating circuit 31 includes
A mode switching circuit 34 for changing the lamp angle of the lamp voltage is provided. In this embodiment, for example, mode A
And a mode B two-stage switch (not shown),
The time constant and the like of the ramp voltage generation circuit 31 are switched to appropriate values. This makes it possible to change how many outside temperatures the output of the switching means 4 is set to 100%. In the present embodiment, in the mode A, the switching means 4 is set at −4 ° C.
Output can be set to 100%, and in mode B -9
The output of the switching means 4 can be set to 100% at 0 ° C. This temperature setting can be changed arbitrarily, and can be changed by setting the lamp voltage generating circuit 31 and the second reference power supply circuit 36. The mode can be switched in three or more stages.

Further, the second differential amplifier circuit 30 has a second 0
A second reference power supply circuit 36 is provided via the volt detection circuit 35. The second differential amplifier circuit 30, the second 0 volt detection circuit 35, and the second reference power supply circuit 36 in the temperature proportional frequency division control means 3 have the same configurations as those used in the temperature detection means 2. Is used.

The switching means 4 is a switching circuit 4
0, an output control circuit 41, and an output 0 volt switching circuit 42. In this embodiment, the switching means 4 is composed of a zero-cross switch so that no switching noise is generated when the power saving unit 1 is operated. In this case, a triac is used as the semiconductor switch in the output 0 volt switching circuit 42.

Since power is supplied to each of the above blocks without a transformer, the power saving unit 1 can be made compact and lightweight. When the power saving unit 1 of this embodiment is used in Japan, the voltage of the power supply line is AC100V.
However, it can be used at a line voltage of the standard of the country or region used, for example, AC200V. In this case, the frequency of the power supply line may be either 50 Hz or 60 Hz.

The power saving unit 1 of the present embodiment having the above-described structure is housed in a casing (not shown) formed of plastic or the like in an arbitrary shape, and is provided with an output outlet 1a. In this case, if a plurality of output outlets 1a are arranged in series, one power-saving unit 1 can provide a plurality of heaters 6a.
Can be connected conveniently.

Next, the operation of this embodiment will be described.
The power saving unit 1 of the present embodiment configured as described above,
When the first sensor 21 of the temperature detecting means 2 detects that the outside air temperature has dropped below a certain value, energization is started and the water pipe 5
Is supplied to the heater 6 only with an alternating current required to generate heat that does not freeze. That is, the power consumption of the heater per unit time is reduced by controlling the voltage of the AC power supply supplied to the heater 6 and the energization time according to the decrease in the outside temperature.

Specifically, when the first sensor 21 of the temperature detecting means 2 detects that the outside air temperature is 3 ° C. or higher, the first differential amplifier circuit 20 does not output a signal and the switching circuit 40 Since it cannot be turned on, power saving unit 1
No output current appears in the output outlet 1a of 1 and no current is supplied to the heater 6.

When the first sensor 21 of the temperature detecting means 2 detects that the outside air temperature is 3 ° C. or lower, the first differential amplifier circuit 20 outputs a signal and the pulse generated by the pulse generating circuit 25. Are sent to the switching circuit 40. In this pulse generation circuit 25, a half wave detection circuit 26 and a 0 volt detection circuit 27 generate a pulse for each half cycle of the 0 volt phase of the power supply line. In other words, if the frequency of the power supply line is 50Hz, 60Hz every 20ms
In that case, a pulse is generated every 16.66 ms, and the switching operation of the switching means 4 can be managed every half cycle.

Further, in the memory circuit 28, the output state of the first differential amplifier circuit 20 is temporarily held, and the 0 volt detection circuit 27 outputs it when the power supply line is in the 0 volt phase. Further, the memory circuit 28 can provide the first differential amplifier circuit 20 with a hysteresis characteristic, thereby stabilizing the power saving unit 1 near the operation start temperature. Note that the 0 volt detection circuit 27 outputs when the first differential amplifier circuit 20 is in the 0 volt phase of the power supply line, so that the load on the first differential amplifier circuit 20 is light and extremely stable operation can be obtained.

The voltage limiter circuit 22 and the low voltage detection circuit 23 provided in the first differential amplifier circuit 20 are the heater 6
The state of the voltage drop in the power supply line and the state of noise on the power supply line that occur when the plug 7 is inserted into and removed from the output outlet 1a is monitored. Thereby, when the voltage drop of the power supply line or the noise of the power supply line is extremely large, the output of the first differential amplifier circuit 20 is stopped to prevent the malfunction of the power saving unit 1.

On the other hand, in the ramp voltage generation circuit 31 of the temperature proportional frequency division control means 3, the sawtooth ramp voltage is swept and the second
It is sent to the differential amplifier circuit 30. This second differential amplifier circuit 3
The second sensor 32 of 0 detects the outside air temperature independently of the first sensor 21, and the second differential amplifier circuit 30 outputs a signal at an interval according to the outside air temperature detected by the second sensor 32. To do. That is, the interval of the output signal of the second differential amplifier circuit 30 becomes long when the outside air temperature is high, and the interval of the output signal becomes short when the outside air temperature is low. In the present embodiment, the mode switching circuit 34 causes the output of the second differential amplifier circuit 30 to be in a continuous state at -4 ° C in mode A, and the output of the second differential amplifier circuit 30 to be in a continuous state at -9 ° C in mode B. Becomes In addition, the second differential amplifier circuit 30 is provided with a second
The 0 volt detection circuit 35 of the second differential amplifier circuit 30
Is output when the power line is at 0 volt phase,
The load on the second differential amplifier circuit 30 is light and an extremely stable operation can be obtained.

The output signals of the temperature detecting means 2 and the temperature proportional frequency dividing control means 3 are sent to the switching means 4,
The switching circuit 40 is turned on to trigger the triac of the output 0 volt switching circuit 42 to supply current to the heater 6 connected to the output outlet 1a.
In this case, when the outside temperature is between 3 ℃ and -9 ℃ (Mode B)
An output current obtained by combining the positive and negative phase currents and the half-wave current is output at appropriate intervals. As a result, a current according to the outside air temperature can be supplied to the heater 6, so that the power consumption of the heater 6 per unit time can be reduced.

FIG. 2 shows the power saving characteristics of the power saving unit 1 of this embodiment. In the characteristic diagram, the horizontal axis represents the outside air temperature, and the vertical axis represents the percentage of the rated power consumption of the heater 6. Also,
The thick line shows the power consumption characteristic of the heater 6 alone, and the thin line shows the power consumption characteristic of the heater 6 when the power saving unit 1 is used. At this time, the mode switching circuit 3 of the power saving unit 1
4 is in the mode B state.

According to this, when only the heater 6 is used alone, the heater 6 starts energization when the outside air temperature is about 5 ° C., and the heater 6 has a rated power consumption due to the operation of the thermal switch built in the heater 6. It is driven with power consumption of about 80% of power. Then, when the outside air temperature falls below about 4 ° C., the heater 6 is driven with a rated power consumption of 100%.

On the other hand, when the power saving unit 1 of this embodiment is used, when the outside air temperature is around 2 ° C., the power consumption is about 40% of the rated power consumption. When the outside air temperature is around 0 ° C, it is about 52%, when the outside air temperature is around -5 ° C, it is about 62%, and when the outside air temperature is around -7 ° C, it is about 78%. Is driven, and when the outside air temperature falls below −9 ° C., the heater 6 is driven with rated power consumption. In this case, when the switch of the mode switching circuit 34 is set to the mode A, the power consumption characteristic of the heater 6 changes as shown by the thin line in FIG. 3, and the heater 6 is driven at the rated power consumption near -4 ° C. Become so.

The states of the output current with respect to changes in the outside air temperature in mode B are shown in FIGS. In each of these figures, the output state of the output 0 volt switching circuit 42 is shown by an oscillograph, the horizontal axis shows the time of 200 ms / div, and the vertical axis shows the voltage of 50 V / div. Further, FIG. 4 shows an output state near 2 ° C., FIG. 5 shows an output state near 0 ° C., FIG. 6 shows an output state near −5 ° C., and FIG. 7 shows −.
8 shows an output state near 7 ° C., FIG. 8 shows an output state near -9 ° C., and FIG. 9 shows an output state when the temperature is below -9 ° C.

From this, it can be understood that the interval until the current is output becomes shorter as the outside air temperature decreases. In addition, in the present embodiment, it is −9 from around 3 ° C.
In the temperature range up to about ℃, since the output current is obtained by combining the positive and negative phase currents with the half-wave current, the heating rate of the heater 6 is fast and a sufficient amount of heat can be obtained even with a small current. High power saving efficiency can be achieved. Further, since switching of the output current is performed when the power supply line has a phase of 0 volt, switching noise does not occur.

The circuit of this embodiment is an example, and it goes without saying that another circuit may be used as long as it has the same function.

[0042]

As described above, according to the power saving unit for a water supply antifreezing heater of the present invention, the following excellent effects are exhibited. That is, since only the alternating current required for the amount of heat generation that does not freeze the water pipe is supplied to the heater according to the change in the outside temperature, the power saving efficiency can be dramatically improved as compared with the conventional example. Further, since the output current is switched when the alternating current has a phase of 0 volt, switching noise does not occur, and there is no radio interference or influence on peripheral electronic devices. Further, the present invention can provide a product having a simple structure and high commercial value.

[Brief description of drawings]

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

FIG. 2 is a diagram showing power saving characteristics of a power saving unit of the present embodiment.

FIG. 3 is a diagram showing changes in power saving characteristics due to mode switching.

FIG. 4 is a diagram showing a state of an output current of the switching means near 2 ° C.

FIG. 5 is a diagram showing a state of an output current of the switching means near 0 ° C.

FIG. 6 is a diagram showing a state of an output current of the switching means near −5 ° C.

FIG. 7 is a diagram showing a state of an output current of the switching means near −7 ° C.

FIG. 8 is a diagram showing a state of an output current of the switching means near −9 ° C.

FIG. 9 is a diagram showing a state of an output current of the switching means at −9 ° C. or lower.

[Explanation of symbols]

 1 Power Saving Unit 2 Temperature Detection Means 3 Temperature Proportional Frequency Dividing Control Means 4 Switching Means 5 Water Pipe 6 Heater 20 First Differential Amplifier Circuit 21 First Sensor 25 Pulse Generation Circuit 27 0 Volt Detection Circuit 28 Memory Circuit 30 Second Differential Amplifier circuit 31 Lamp voltage generation circuit 32 Second sensor 34 Mode switching circuit

Claims (5)

[Claims] 1. A power-saving unit, which is connected to a heater for preventing water from freezing and which is wound around a water pipe, and controls AC power supplied to the heater to reduce power consumption of the heater, in response to changes in outside air temperature. A power saving unit for a water freezing prevention heater, characterized in that it is configured to control a voltage and an energization time of an AC power supply supplied to a heater by a heater. 2. A temperature detecting means for detecting a change in temperature,
Based on the output of the temperature detecting means, it comprises a temperature proportional frequency dividing control means for controlling the voltage and energization time of an AC power source for energizing the heater, and a switching means for controlling the energization of the heater. 100% output of the switching means Sometimes the output current of either full wave current or both positive and negative phase current is supplied to the heater to use the heater at the rated output. When the output of the switching means is less than 100%, the full wave current or positive and negative phase current By supplying an output current that is a combination of any current and half-wave current to the heater at appropriate intervals,
The power consumption of the heater per unit time is reduced.
A power saving unit for the water supply freeze prevention heater described. 3. A temperature detecting means in which a first sensor is connected to the first differential amplifier circuit, and a temperature proportional frequency dividing control means in which a second sensor and a ramp voltage generating circuit are connected to the second differential amplifier circuit. 3. The power saving unit for a water antifreezing heater according to claim 1, wherein the output is connected to the switching means, and the switching circuit of the switching means is controlled by the pulse of the pulse generating circuit triggered by the 0 volt detection circuit. 4. When the output of the switching means is less than 100%, a memory circuit is provided at the output of the first differential amplifier circuit, and the pulse generated by the pulse generating circuit is managed every half cycle of the AC power supply frequency. The heater reduces the power consumption of the heater per unit time by supplying an output current obtained by combining a half-wave current and a full-wave current or both positive and negative phase currents to the heater. The power saving unit for the water supply freeze prevention heater described in one. 5. The lamp voltage generating circuit is provided with a mode switching circuit, and by changing the time constant of the lamp voltage generating circuit to an appropriate value, the time interval of the output of the temperature proportional frequency dividing control means is changed to a unit time. The power saving unit for a water antifreezing heater according to claim 1, wherein the power consumption of the heater per hit is changed to change the power saving rate.