JPS62103494A - Device for detecting air-lock condition of pump - Google Patents

Abstract

PURPOSE:To accurately grasp an air lock condition and prevent the failure of a pump due to idle rotation of a rotor by judging a lower limit flow rate in addition to the pressure drop in a water feed pipe and detecting an air lock condition. CONSTITUTION:When a pump P in operating condition, first, a lower limit pressure judging means 13 receives a pressure signal S3 from a pressure detecting means 5, to judge whether a lower limit pressure is reached or not. When pressure is judged to have reached the lower limit, a lower limit flow rate judging means 14 receives a flow rate signal S5 from a flow rate detecting means 4 and judges whether a lower limit flow rate is reached or not. When both flow rate and pressure are judged to have reached their lower limits, an air lock condition signal S7 is outputted from the lower limit flow rate judging means 14, stopping a pump while giving a warning.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an aerodynamic ffl'+ detection device for a pump, and particularly to a device for detecting an aerodynamic condition ffl'+ when the load becomes large or during self-priming operation. Preventing 1
The present invention relates to an air condition detection device according to the present invention.

BACKGROUND ART Generally, when a water supply pump inhales a large amount of air bubbles during operation and reaches an aerodynamic state, the rotor will idle and cause failures such as seizing of the rotating shaft. The alarm system is activated as appropriate. Conventionally, the aerodynamic state detection device monitors the pressure in the water supply pipe on the discharge side of the pump.
When this pressure drops below a preset allowable lower limit pressure, a system has been adopted that detects this and issues an alarm.

However, the conventional aerodynamic condition detection device described above only checks the pressure drop in the water supply pipe.
When a large load is applied to the pump, that is, when a large amount of water is consumed, the pressure similarly becomes low, and this also has the drawback of being erroneously detected as an aerodynamic condition. Further, when the water supply pump is a self-priming type pump, there is also a drawback that a low pressure state during self-priming operation is mistakenly detected as an aerodynamic state.

Purpose 〉 The purpose of the present invention is to provide a lower limit flow rate determining means and an alarm signal generation means in view of the problems such as false detection during heavy loads or self-priming operation due to structural limitations of the aerodynamic state detection device based on the above-mentioned prior art. It is an object of the present invention to provide an aerodynamic condition detection device which can eliminate the above-mentioned drawbacks and accurately detect an aerodynamic condition by adding means.

Structure 〉 The structure of the present invention in accordance with the above object is to determine the operating state of the pump based on the drive signal to the switch means of the pump drive motor, obtain the operating state signal, and adjust the pressure according to the pressure in the water supply pipe. A pressure signal is output from the detection means, and a lower limit pressure signal is obtained by determining that the pressure represented by the pressure signal is below a preset lower limit pressure, while the flow rate detection means is configured to output a pressure signal according to the flow rate in the water supply pipe. outputs a flow rate signal, determines that the flow rate represented by the flow rate signal is below a preset lower limit flow rate, obtains a lower limit flow rate signal, and simultaneously outputs the above operating status signal, lower limit pressure belief, and lower limit flow rate signal. The gist of this invention is that the airlock condition is determined by the airlock condition determination means based on the airlock condition supplied, and an airlock condition signal is output. In response, the alarm signal generation means outputs an alarm signal or a stop command signal after a preset period has elapsed.

Embodiments Next, embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram simultaneously showing the hardware configuration and software "2" function realizing means, in which an electric motor M for driving a pump P is connected to a power source 2 via a switch means 1, On the other hand, a flow rate detection means 4 is provided in the water supply pipe 3 of the pump P, and a pressure detection means 5 is also attached thereto. 6 is a pressure adjustment tank.

Reference numeral 10 denotes an arithmetic processing unit, and its function implementation means include a drive signal generation means 11 that supplies a drive signal S1 to the switch means 1, and an operation state discriminator that receives the drive signal S1 and outputs an operation state signal S2. means 12, a lower limit pressure determining means 13 which outputs a lower limit pressure signal S4 upon receiving the pressure signal S3 from the pressure detecting means 5, and determining a lower limit flow rate upon receiving the flow rate signal S5 from the flow rate detecting means 4. The lower limit flow rate determining means 14 outputs the signal S8, and the operating state determining means 12, the lower limit pressure determining means 13, and the lower limit flow rate determining means 14 are followed by the operating state signal S2 and the lower limit pressure signal S.
4 and the lower limit flow rate signal S6, and outputs an airlock condition signal S7.
and an alarm signal generating means 16 following the aerodynamics state determining means 15 and outputting an alarm signal or a stop command signal S8 in response to the aerodynamics state signal S7.

The air condition determination signal S7 then reaches a display (not shown) and lights up a lamp. Further, the alarm signal S8 causes a buzzer (not shown) to sound, and the stop command signal S8 reaches the drive signal generation means 11, and forcibly eliminates the drive signal S1.

The operation of the above configuration will be described below with reference to FIGS. 2 and 3 showing flowcharts of the arithmetic processing section 10.

In the arithmetic processing unit 10 that has started (Fig. 2g), the operating state determining means 12 determines whether or not the pump P is in the operating state (Fig. 2 b), and when the determination result is YES, the pressure detecting means Upon receiving the pressure signal S3 from 5, the lower limit pressure determining means 13 compares and determines the magnitude relationship between the pressure and a preset lower limit pressure (FIG. 2C). When the determination result is YES, that is, when the medium pressure in the water supply pipe 3 has decreased to the lower limit pressure, the lower limit flow rate determining means 14 receives the flow rate signal S5 from the flow rate detecting means 4 and determines that the flow rate is Compare and judge the magnitude relationship with the preset lower limit flow rate (
Figure 2 d). When the determination result is YES, that is, when the medium flow rate in the water supply pipe 3 has decreased to the lower limit flow rate,
It outputs an aerodynamic status signal S7 (Fig. 2e). That is, when the pump P is in operation and the pressure of the medium in the water supply pipe 3 has decreased to the lower limit pressure and the flow rate has decreased to the lower limit flow rate, the aerodynamic condition is detected and the aerodynamic condition signal S7 is detected. is sent to a display (not shown) to light a lamp. The arithmetic processing unit IO then determines whether or not to continue the monitoring for detecting the aerodynamic condition (Fig. 2 f). If it is to be stopped, the detection work is finished (Fig. 2 g); if it is to be continued, it is determined whether the monitoring is to be continued or not. Return to the step in Figure 2 and repeat the subsequent steps (Figure 2 b-f). Incidentally, if any one of the determination of the operating state, the lower limit pressure, and the lower limit flow rate is No, the process skips to step f in FIG. 2 and performs the subsequent steps.

Next, the operation of the second invention will be explained based on FIG. 3. The steps from FIG. 3 g to FIG.
It is the same as the process. Then, when the aerodynamic status signal S7 is output (Fig. 3e), an internal timer is activated (Fig. 3f) to measure the duration of the aerodynamic status signal S7. When the internal timer times up beyond the self-priming period of the pump P, an internal interrupt occurs (Fig. 3g), and an alarm signal or stop command signal S8 is output from the alarm signal generation means 16 (Fig. 3h). . When outputting this signal S8 as an alarm signal, an alarm buzzer (not shown) is sounded, and when outputting it as a stop command signal, the signal S8 is sent to the drive signal generation means 11 to forcibly extinguish the drive signal S1. or a combination of both.

When the alarm signal or stop command signal S8 is output, the process returns (Fig. 3 i) and determines whether to stop monitoring (Fig. 3 j), but the subsequent operation is as in the case of Fig. 2. It is similar to Also, if any of the judgments of the operating state, lower limit pressure, and lower limit flow rate is No, the timer is reset (Fig. 3 1) and the process moves to Fig. 3 j step. be.

Second Embodiment> By the way, in the first embodiment of the second invention, the aerodynamic status signal S7 output from the aerodynamic status determining means 15 continues during the self-priming period of the pump P. The system is designed to output an alarm signal/stop command signal S8 only when the pump is in use, but normally, this type of water pump is operated for a long period of time, ranging from several tens of hours to several days or more. Since continuous operation of the pump is normal, it is only necessary to compare and determine whether the duration of the aerodynamic status signal S7 is longer than the self-priming period, for example, only when the pump is started once every few days. All that is needed is to avoid erroneously detecting the self-priming operation as an aerodynamic state. However, in the first embodiment, in which the self-priming period is used as the reference period when determining the duration of the aerodynamic status signal S7 that occurs thereafter for the purpose of detecting the aerodynamic status, the self-priming period is used as the reference period. Since the time required is longer, there is a risk that excessive force will be applied to each part of the pump, which may have an adverse effect.

Therefore, in the second embodiment shown in FIG. 4 and below, the self-priming period is used as the reference period for detecting the aerodynamic condition during the duration of the aerodynamic condition signal only when the pump is started, and thereafter, A predetermined period that is considerably shorter than the self-priming period is set, and this period is used as the reference period for the aerodynamic f
By determining the duration of the C1 signal, it is possible to prevent the aerodynamic state from continuing for an unnecessarily long period of time.

In the second embodiment, a long-time timer TM2 is internally set to a period slightly longer than the self-priming period;
A short-time timer TMI set to a period considerably shorter than the self-priming period is incorporated, and an auxiliary timer TM3 set to a period corresponding to the chattering period of the aerodynamic status signal is incorporated. , a second flag register is provided which sets a flag "1" when the completion of the self-priming operation is detected.

FIGS. 5 to 7 show time charts for detecting the aerodynamic state, and the three timers TM1, TM2,
The interrelationship of the states of TM3 and the second flag (the contents of the second flag register) over time is shown.

In Fig. 5, when the aerodynamic status signal S7 is output (Fig. 5 (A) a), the aerodynamic status is displayed (
In Fig. 5 CB) a), the long time timer TM2 and the short time timer TMI are set respectively to measure the duration of the aerodynamic status signal S7 (Fig. 5 (D) a).
(E) a), then when the aerodynamic status signal S7 disappears within the set period T2 of the long timer TM2 (i.e., the self-priming period of the pump) (Figure 5(A) b), the aerodynamic status is displayed. At the same time, the long-term timer TM2 and short-time timer TM1 are reset (FIG. 5(D)b, FIG. 5(E)b).
At the same time, the auxiliary timer TM3 is set and starts timing the chattering period T3 (FIG. 5(G)a).

If the disappearance of the airlock state signal S7 is due to chattering, the airlock state signal S7 is output again within the chattering period T3 (Fig. 5(A)C
), displays the aerodynamic status (Fig. 5(B)C), and displays the long timer TM2 and short timer TMI.
5(D)c, FIG. 5(E)c), and reset the auxiliary timer TM3 (FIG. 5(G)b).

Then, the aerodynamic status signal S7 indicates the long time timer TM.
If it disappears again within the set period 12 of 2 (Fig. 5 (A)
d), the auxiliary timer TM3 is set (see Figure 5 (G)
)C), when the timer TM3 measures the chattering period T3 (FIG. 5(G) d), the second flag rlJ is set in the second flag register (FIG. 5(G) d).
F)a) In this case, the fact that the aerodynamic status signal S7 is not re-generated due to chattering immediately after disappearance, and the long-term timer TM2 has not timed up indicates that the pump is self-priming. , that is, the continuation of the aerodynamic status signal S7 up to that point is due to self-priming operation and is not due to a true aerodynamic status. Even if the short-time timer TMI times up during this time (the fifth
(E) d), at this point, the second flag, which will be described later, is not set to "1" (FIG. 5F), so the alarm signal/stop command signal S8 is not output (FIG. 5C).

In this way, after the self-priming operation at the time of starting the pump is avoided from being erroneously detected as an aerodynamic state, the pump operates according to the time chart shown in FIG. 6.

When the aerodynamic status signal S7 is output (Fig. 6 (A)
a), the aerodynamic status is displayed (Fig. 6 (B) a).
), the long-term timer TM2 and the short-time timer TMI are set (Fig. 6 (D) a, Fig. 6 (E) a) The operation is similar to that in Fig. 5, but the aerodynamic status signal 5 is set.
During the 70m run, when the short-time timer TMI measures the set period T1 (Fig. 6 (E) b), it is checked whether the second flag is set to "1" or not, and the Since rlJ stands as a result of the operation (Fig. 6 (F)
)b), an alarm signal/stop command signal S8 is output (FIG. 6(C)a). , Incidentally, if there is a failure in the self-priming operation when the pump is started, and the long time timer TM2 times up without the second flag "l" being set, similar to the operation shown in FIG. As shown in the time chart of FIG. 7, when the long time timer TM2 fails to tie up (FIG. 7(D) b), the alarm signal/stop command signal S8 is output (FIG. 7(C) a). During this time, the short-time timer TMI has already timed out (t57 (E)b), but at this point, the timer TMI has already timed out twice.
Because the flag "l" is not set (Fig. 7 (F) C)
, the alarm signal/stop command signal S8 is never output.

Here, for example, the setting period T2 of the long timer TM2
By selecting approximately 10 minutes in relation to the self-priming period of the pump, and selecting the setting period Tl of the short-time timer TMI to approximately 1 degree, the time required to detect the aerodynamic state after the self-priming operation is completed can be reduced. It can be significantly shortened.

Next, the timers TMI, 1M2, T in the second embodiment
The overall operation of the arithmetic processing unit IO (also used in FIG. 1) for ensuring the above-mentioned operations of M3 and the second flag register will be explained based on FIGS. 4A to 4B showing its flowchart. It is as follows.

The steps from a to d in FIG. 4A are the same as the steps from a to d in FIG. 3. Then, the results of the operation status determination, lower limit pressure determination, and lower limit flow rate determination are all YES.
When S, reset the auxiliary timer TM3 and (
4A e), the 4th step is to output the aerodynamic status signal S7.
Figure A d), short-time timer TMI and long-time timer TM
2 and 2 simultaneously (Fig. 4A g) (Fig. 4A h
). Short time timer TM1. ! l:Long time timer TM
2 respectively measure the duration of the aerodynamic status signal S7, and the short time timer TMI measures the duration of the aerodynamic status signal S7.
When the time is counted, an internal interrupt occurs (Fig. 4B i), it resets itself (Fig. 4B j), and then it is determined whether the second flag is set to "1" (Fig. 4B k).

If the judgment result is NO, that is, if the self-priming operation of the pump has not been completed, return (Fig. 4B m).
, it is determined whether or not to stop monitoring (FIG. 4A p), and the subsequent operations are the same as those shown in flowchart 1 of FIG. 3.

Also, the second flag judgment result (Fig. 4B k) is YES,
That is, when the self-priming operation has already been completed, the alarm signal/stop command signal S8 is output (FIG. 4B, 1), and then the return is performed (FIG. 4B, m), while the timer TM2 is set for the set period, that is, When the self-priming period T2 is timed, an internal interrupt occurs and after resetting itself (Fig. 4B n),
8), outputs an alarm signal/stop command signal S8 (Fig. 4B, 1), and returns (Fig. 4B, m).

Determination of the operating state (Fig. 4A b), determination of the lower limit pressure (
If either of the judgment results of Fig. 4A c) or lower limit flow rate judgment (Fig. 4A d) is No, it is necessary to judge whether an alarm has already been issued or not (Fig. 4A r), and the judgment result When the result is No, it is determined whether the immediately previous state was an aerodynamic state (FIG. 4A, S). When the determination result (S in Fig. 4A) is YES, the auxiliary timer T
Set M3 (Fig. 4B j), aerodynamic status signal S
7 is extinguished (FIG. 4B, u), and then the short-time timer TMI and long-time timer TM2 are reset (FIG. 4B, v), and then the process moves to FIG. 4B, p. During this time, the 4th
In the process shown in Figure B, the auxiliary timer TM3 measures the duration of the extinction state of the airlock state signal S7.
When the set period, that is, the chattering period T3, was timed, an internal interrupt occurred (Fig. 4B W), the flag was set to "1" for the second time (Fig. 4B x), and the auxiliary timer TM3 was reset (Fig. 4B y), then returns (Z in Figure 4B).

On the other hand, the fourth A Ui! The judgment result in the Jr process is Y.
When it is ES, the process moves to step V in FIG. 4A, and the short-time timer TMI and long-time timer TM2 are reset.

If the determination result in step S in FIG. 4A is NO, the process moves to step U in FIG. 4A to eliminate the aerodynamic status signal.

Effects> As described above, according to the present invention, the operating state is determined by receiving a drive signal to the switch means for supplying power to the electric motor, and the operating state of the medium in the water supply pipe is determined by receiving the pressure signal from the pressure detection means. Determine whether the pressure has decreased to the lower limit pressure, determine whether the flow rate has decreased to the lower limit flow rate in response to the flow rate signal,
By adopting a configuration that outputs an aerodynamic status signal when all of the above judgment results are YES, even when a large load occurs and a large amount of water supply is consumed, resulting in a pressure drop and the pressure drops below the lower limit pressure, the flow rate If the flow rate is large, the result of the comparison with the lower limit flow rate is NO1, that is, it is determined that the flow rate has not decreased to the lower limit flow rate, so an aerodynamic status signal is not output, and an erroneous error occurs when a large load occurs. This has the excellent effect of not detecting an aerodynamic condition.

According to the second invention, the duration of the aerodynamic status signal is measured from the time when it is output, and the alarm signal or stop command signal is not issued until the duration exceeds the self-priming time of the pump. By outputting , even if the pressure and flow rate are low during the self-priming period in the self-priming pump, this is not erroneously detected as an aerodynamic state.

Furthermore, the device for detecting the aerodynamic condition can share a part of the on/off control device for keeping the water supply pressure of the pump constant, such as the drive signal generation means and the pressure detection means. It also has the advantage of being economical.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, and FIG. 1 is a block diagram, FIG. 2 is a flowchart I, FIG. 3 is a flowchart in the second embodiment of the invention, and FIG. This relates to another embodiment of the invention of FIGS. 4A to 4A.
FIG. 4B is a flowchart of the arithmetic processing unit 10, and FIGS. 5 to 7 are flowcharts of aerodynamic state detection. P... Pump M... Electric motor 1... Switch means 3... Water supply pipe 4... Flow rate detection means
5... Pressure detection means lO... Arithmetic processing section 11.
...Drive signal generation means 12...Operating state determination means 13...Lower limit pressure discrimination means 14...Lower limit flow rate discrimination means 15...Aerodynamic state discrimination means 16...Alarm signal generation means Sl... Drive signal S2... Idle state signal S3
...Pressure signal S4...Lower limit pressure signal S5...
・Flow rate signal S8...Lowest flow rate signal S7...Aerodynamic status signal

Claims (2)

[Claims] (1) A pump P that supplies water to the water supply pipe 3; an electric motor M that receives power and drives the pump P; a switch means 1 that receives a drive signal S1 and supplies power to the electric motor M; and a switch means an operating state determining means 12 that determines the operating state of the pump based on the supply of the drive signal S1 to the pump 1 and outputs an operating state signal S2; Pressure detection means 5 that outputs a pressure signal S3 and a pressure signal S3
A lower limit pressure determining means 13 is provided in the water supply pipe 3 and outputs a lower limit pressure signal S4 by determining that the pressure represented by is equal to or lower than a preset lower limit pressure. A lower limit flow rate determination means 14 that determines that the flow rate represented by the flow rate signal S5 is less than or equal to a preset lower limit flow rate and outputs a lower limit flow rate signal S6, an operating state signal S2, a lower limit pressure signal S4, and a lower limit flow rate signal. An airlock state detection device for a pump having an airlock state determination means 15 for determining an airlock state based on simultaneous supply with S6 and outputting an airlock state signal S7. (2) a pump P that supplies water to the water supply pipe 3; a motor M that receives power and drives the pump P; a switch means 1 that receives a drive signal S1 and supplies power to the motor M; and a switch means 1. an operating state determining means 12 that determines the operating state of the pump based on the supply of the drive signal S1 to the pump and outputs an operating state signal S2; Pressure detection means 5 that outputs pressure signal S3 and pressure signal S3
A lower limit pressure determining means 13 is provided in the water supply pipe 3 and outputs a lower limit pressure signal S4 by determining that the pressure represented by is equal to or lower than a preset lower limit pressure. a flow rate detection means 4 that outputs a corresponding flow rate signal S5; a lower limit flow rate determining means 14 that determines that the flow rate represented by the flow rate signal S5 is below a preset lower limit flow rate and outputs a lower limit flow rate signal S6; Airlock state determining means 15 that determines the airlock state based on the simultaneous supply of the operating state signal S2, the lower limit pressure signal S4, and the lower limit flow rate signal S6, and outputs the airlock state signal S7.
An airlock state detection device for a pump, comprising: and an alarm signal generating means 16 that outputs an alarm signal or a stop command signal S8 after a preset period has elapsed in response to the airlock state signal S7.