JPS61250388A - Method for preventing freezing of pump - Google Patents

Abstract

PURPOSE:To enable the freezing prevention in a pump to be performed efficiently and inexpensively by supplying electric power to a pump driving motor with its exhaust side passage closed so that the motor is set in motion and transmitting the motor rotation to the pump so as to force the pump to generate heat. CONSTITUTION:Ordinarily, a valve 11 is in the open state. When a switch 9 is closed under this state, electric power is supplied from a power supply 8 to a motor 2, which is rotated to operate a pumping means 3. Now, for example, when the temperature in the early morning falls to some sub-zero temperature and the pumping means 3 is in the stop state, the water in a pump 1 is likely to freeze. In this case, since a detection signal outputted from a temperature sensor 6A is below the set point for a level judging circuit 6B, said circuit 6B outputs a signal S to a heater controlling circuit 7. Herewith, said circuit 7 supplies appropriate electric power from the power supply 8 to freezing prevention heaters 5A, 5B so that these heaters become energized. Thereby, the pump 1 is warmed up through thermal conduction from the freezing prevention heaters 5A, 5B such that the water contained in it can be protected from freezing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for preventing water from freezing in a pump.

[Conventional technology]

Figure 3 is a diagram showing the configuration of the pump antifreeze device.
, In the figure, 1 is a pump that transports water when driven, lA
is the inlet side flange of the pump 10, 1B is the outlet side flange of the pump 1, and 2 is the flange provided integrally with the pump 1.
3 is a pump means consisting of pump 1 and motor 2, 4A is a water inlet pipe, 4B is a water outlet pipe, 5A
, 5B are antifreeze heaters placed near the flanges 1A and IB, 6A is a temperature detector that outputs a temperature detection signal in response to the external temperature around the pump 1, and 6B is a temperature detection signal whose temperature is a set value. 7 is a heater control circuit that controls the heating amount of the antifreeze heaters 4A and 4B according to the output signal from the level determination circuit 6B; 8 is a power source for the motor 2; 9 is a This is a manual switch for electrically connecting and disconnecting the power source 8 to the motor 2. Reference numeral 9 denotes a pump control panel, which is provided with a level determination circuit 6B, a heater control circuit 1, and a manual switch 9. FIG. 4 is an explanatory diagram of the operation of the conventional device.

Next, the operation will be explained. When the switch 9 is closed, power is applied from the power source 8 to the motor 2, and the rotation of the motor 2 causes the pump means 3 to operate. By this operation), water is transported in the direction of the arrow shown. Conversely, when the switch 9 is opened, the electrical connection between the power source a and the motor 2 is cut off, the pump means 3 is stopped, and the water is stopped. At times when the temperature is at its lowest, such as in the early morning, when the temperature is below 0° C. and the pump means 3 is stopped, the water in the pump 1 is likely to freeze. At this time, since the temperature detection signal 2L outputted from the temperature detector 6A is less than the set value of the level determination circuit 6B, the level determination circuit 6B outputs the signal 8 to the heater control circuit 7. At this point, the heater control circuit T supplies appropriate power from the power supply 8 to the anti-freezing heaters 5A and 5B.
Make the antifreeze heaters 5A and 5B generate heat [Step 82
]. The entire pump 1 is warmed by heat transfer from the antifreeze heaters 5A and 5B, and water in the pump 1 is prevented from freezing. Note that when it is determined in step 81 that the external temperature is high and the temperature detection signal exceeds the set value, the antifreeze heaters 5A and 5B are heated (step 83).

[Problem that the invention seeks to solve]

The conventional method for preventing freezing of pumps as described above requires an anti-freezing heater, a heater control circuit, and the associated wiring, so the equipment cost is high.
7 Even if an attempt is made to warm the pump by heat conduction from around the lunge, heat will escape to the water pipe side due to heat conduction and water convection, and the heat used to heat the pump will not be used efficiently to prevent freezing. There were problems such as:

This invention was made to solve the above-mentioned problems, and its purpose is to provide a method for preventing freezing of a pump that can effectively utilize existing equipment and efficiently use heat for freezing prevention. shall be.

[Means for solving problems]

The method for freezing a pump according to the present invention detects the temperature around the outside of a pump that transports liquid or the temperature inside the pump, and freezes the liquid inside the pump by heating the pump according to the level of the detected value. In a method for preventing freezing of a pump, the pulp installed on the discharge side of the pump is closed, power is supplied to the motor installed integrally with the pump, the motor generates heat, and this heat is transferred to the pump. It was designed to convey information efficiently.

[Effect]

The method for preventing freezing of a pump in this invention is to close the flow path on the discharge side of a pump that transports liquid, detect the temperature around the outer periphery of the pump or inside the pump, and use this detected value as the temperature of the liquid inside the pump. If it is determined that the value corresponds to the freezing temperature, power is supplied to the motor for driving the pump, but since the flow path is closed, the pump cannot pump, and the power given to the motor is not supplied to the motor. This heat is lost and consumed, and this heat is transferred to the liquid in the pump via the pump, thereby preventing the liquid in the pump from freezing.

[Metal practice]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the symbols 1, IA, IB, 2, 3.4.

4B, 6A, 6B, 8, 9.10 are completely the same as or equivalent to the conventional device, 11 is a pulp provided near the flange 1B and in the water outlet pipe 4B, 12 is a power source 8 and a level determination circuit This is a pump rotation control circuit that inputs the output of the pump 6B and controls the rotation of the motor 2 of the pump means 3. Note that 9A and 9B are fixed terminals of the switch 9, the terminals 9 are connected to the power supply 8, and the terminal 9B is connected to the pump rotation control circuit 12.
It is connected to the output side. The switching side of the switch 9 is connected to the input side of the motor 2. FIG. 2 shows a flow chart for explaining the operation of this embodiment.

Next, a method for preventing freezing of the pump in the pump device having the above configuration will be explained. When preventing the pump from freezing, the pulp 1lt is fully closed and the switch 9 is switched to the terminal 9B side. The temperature detector 6A detects the external ambient temperature of the pump 1.

The level determination circuit 6B determines whether the temperature detection signal output from the temperature detector 6A is below a set value [Step 8
1G),. If the temperature detection signal is below the set value, the level determination circuit 6B outputs the signal S.

The pump rotation control circuit 12 which receives this signal 8 supplies power to the motor 2 (by connecting the power supply 8 to the motor 2) and operates the pump means 3 only during the time t1.
Step 811]. Here, even if the pump means 3 operates, the flow rate is zero due to the closed state of the pulp 11, and the motor 2
Most of the input power is consumed as Joule heat due to the impedance within the motor 2. This heat warms the pump 1 directly from inside the pump means 3 and, by heat conduction, warms the water inside the pump 1 so as not to freeze. Next, when the operating time t1 of one pump means 3 has elapsed, the pump rotation control circuit 12 cuts off the connection between the power source 8 and the motor 2, stops the rotation of the motor 2 only for a time t2, and controls the pump means 3.
t- put into hibernation state [step 812]. Next, the process returns to step 810 described above, and the same operations as described above are repeated. If the level determination circuit 6B determines in step 810 that the above-mentioned temperature detection signal exceeds the above-mentioned set value, the level determination circuit 6B
- Since there is no output, the pump rotation control circuit 1 stops the pump means 3.

Here, the operating time t1 and rest time t2 of the pump means 3 are determined appropriately based on the rate of temperature rise of the water in the pump means 3 and pump i due to Joule heat generated by the motor 2, and the rate of temperature fall of the pump means 3 when it is stopped. is set to In addition, since the amount of heat accumulated in the pump 1 etc. warmed by the operation of the pump means 3 for the time t□ is very large,
Even if the pump means 3 is put into a rest state, the temperature of the pump 1 etc. does not drop suddenly. Therefore, even if the pump means 3 is operated intermittently as described above, freezing of the water in the pump 1 is effectively prevented. In the above embodiment, the six temperature detectors measure the external heat ambient temperature of the pump 1. However, the temperature can also be detected by providing the detection end inside the pump 1.Furthermore, in the above embodiment, when the pump 1 is protected from freezing, the power supply 8 is directly connected to the motor 2, and the motor 2 is In addition to this, by controlling the output of the power source 8, the heater control circuit 7 applies less electric power to the motor 2 than during the constant speed rotation described above to rotate the motor 2 at a variable speed. In this case, an unreasonable load is not placed on the motor 2, and the motor 2 can be used for a long time.

In addition, the level determination circuit 6B outputs a signal st- of a magnitude corresponding to the difference between the temperature detection signal and the set value.
The heater control circuit 7 adjusts the electric power given to the motor 2 according to the magnitude of the signal S, or adjusts the ratio between the operating time t1 and the rest time t2 of the motor 2 according to the magnitude of the signal S. By changing K, it is possible to cause the motor 2 to generate the lowest necessary amount of Joule heat to prevent the pump 3 from freezing depending on the low external temperature.

〔Effect of the invention〕

As described above, according to the present invention, the heat loss generated by closing the flow path of the pump discharge example and operating the pump means is used as a heat source for preventing freezing of the pump, so that the inside of the pump means can be used as a heat source. Thermal efficiency is good due to heating, and the use of existing equipment such as pump means has the effect of reducing the cost of anti-freezing.

[Brief explanation of drawings]

FIG. 1 is an apparatus system diagram for explaining the method for preventing freezing of a pump according to an embodiment of the present invention, FIG. 2 is a flow diagram for explaining the method for preventing freezing of a pump together with FIG. 1, and FIG.
The figure is an apparatus system diagram for explaining the conventional method, and FIG. 4 is a flow diagram for explaining the conventional method. In the figure, 1 is a pump, 2 is a motor, 3 is a pump means, 6A is a temperature detector, 6B is a level determination circuit, 8 is a power source, 9 is a switch, 11 is a pulp, and 12 is a pump rotation control circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] Freezing prevention for pumps that prevents the liquid inside the pump from freezing by detecting the external ambient temperature of a pump that transports liquid or the temperature inside the pump and heating the pump according to the level of this detected value. In the method, the motor generates heat by supplying electric power to the motor for driving the pump while the flow path of the discharge example of the pump is closed;
A method for preventing freezing of a pump, characterized by efficiently transmitting this heat to the pump to heat the pump.