A method for detecting pump shaft abnormalities

Abstract

This invention belongs to the field of water pump technology, specifically referring to a method for detecting pump shaft anomalies, including the following steps: S1: Initialization; S2: Other tasks; S3: Detecting the current motor current; S4: If I c >I0*x, execute S5; otherwise execute S6; S5: Increment the number of stalls, execute S10; S6: If I c >I T +I0*y, execute S7; otherwise execute S8; S7: Increase the number of times the valve is suddenly opened by 1, execute S10; S8: If I c If I > 0, execute S9; otherwise, execute S10; S9: cumulative time t i , t=t+t i Execute S10; S10: Calculate r, p(g), p(d), p(f); S11: Calculate P; S12: If P > P0, determine an anomaly and return to S2; otherwise, determine normal and return to S2. This invention can predict pump shaft anomalies so that timely countermeasures can be taken to avoid serious consequences such as mechanical damage, fluid leakage, and system failure caused by pump shaft breakage.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water pumps, in particular to a pump shaft abnormality detection method. BACKGROUND

[0002] In water pump applications, especially deep well pump applications, pump shaft breakage often occurs.

[0003] Due to the difficulty of using contact detection methods, and the deep well pump is submerged underwater, it is also difficult to be frequently lifted to the ground for maintenance, so a method is needed to predict the abnormality of the pump shaft, so as to take timely measures to avoid the serious consequences of pump shaft breakage, fluid leakage, system failure, etc. SUMMARY

[0004] The purpose of the present application is to provide a pump shaft abnormality detection method which can predict the abnormality of the pump shaft, so as to take timely measures to avoid the serious consequences of pump shaft breakage, fluid leakage, system failure, etc.

[0005] The present application is implemented as follows:

[0006] A pump shaft abnormality detection method, comprising the following steps:

[0007] S1: Initialize the single-chip microcomputer, set the rated current I0, constant s, multiple x, coefficient y, time average probability a of high-speed large torque leading to pump shaft abnormality, probability b of single blocked rotation leading to pump shaft abnormality, probability c of each sudden opening of large valve leading to pump shaft abnormality, pump shaft abnormality probability threshold P0, set the number of blocked rotations n=0, the number of sudden openings of large valves m=0, the high-speed large torque time t=0;

[0008] S2: Process other tasks;

[0009] S3: Detect the current motor current I c , and record the motor current before time T as I T ;

[0010] S4: If I c >I0*x, execute step S5; otherwise, execute step S6;

[0011] S5: Blocked rotation number n=n+1, continue to execute step S10;

[0012] S6: If I c >I T + I0*y, execute step S7; otherwise, execute step S8;

[0013] S7: The number of sudden openings of large valves m=m+1, continue to execute step S10;

[0014] S8: If Ic If I0, then step S9 is executed; otherwise, step S10 is executed.

[0015] S9: Accumulate I c Time t when I0 i High-speed large-torque time t=t+t i Continue to execute step S10.

[0016] S10: Calculate coefficient r according to formula r=I c / (I0*s); calculate probability p(g) of pump shaft abnormality in high-speed large-torque time according to formula p(g)=(1+r)*a*t; calculate probability p(d) of pump shaft abnormality in blocked-torque mutation time according to formula p(d)=b*n; and calculate probability p(f) of pump shaft abnormality in sudden opening of valve according to formula p(f)=c*m.

[0017] S11: Calculate pump shaft abnormality probability P according to formula P=p(g)+p(d)+p(f).

[0018] S12: If P>P0, then determine that the pump shaft is abnormal, and return to step S2; otherwise, determine that the pump shaft is normal, and return to step S2.

[0019] In the pump shaft abnormality detection method, in step S9, the time t when I0 c is accumulated. i The time t is obtained by a timer of the water pump controller.

[0020] In the pump shaft abnormality detection method, in step S3, the current of the motor is detected in real time by a current sensor.

[0021] In the pump shaft abnormality detection method, in step S3, the current of the motor is sampled by a current sampling resistor.

[0022] In the pump shaft abnormality detection method, in step S12, when the pump shaft is determined to be abnormal, a warning signal is sent, and the current pump shaft abnormality probability P value is sent to the user.

[0023] The present application has the following advantages over the prior art:

[0024] This invention determines the pump's status by monitoring the motor's current. It then calculates the probabilities of pump shaft abnormalities (p(g)) during high-speed, high-torque operation, (p(d)) during sudden changes in stall torque, and (p(f)) during sudden valve opening using formulas. Finally, it sums these probabilities and compares them with a pump shaft abnormality probability threshold (P0) to determine if the pump shaft is abnormal. This allows for prediction of pump shaft abnormalities and timely implementation of countermeasures to prevent serious consequences such as pump shaft breakage, mechanical damage, fluid leakage, and system failure. Attached Figure Description

[0025] Figure 1 This is a control flowchart of Embodiment 1 of the present invention.

[0026] Figure 2 This is a circuit schematic diagram of Embodiment 1 of the present invention.

[0027] Figure 3 This is the circuit principle of Embodiment 2 of the present invention. Figure 1 .

[0028] Figure 4 This is the circuit principle of Embodiment 2 of the present invention. Figure 2 . Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments. See also: Figures 1-4 :

[0030] Example 1: See Figure 1 , 2 :

[0031] A method for detecting pump shaft abnormalities includes the following steps:

[0032] S1: Initialize the microcontroller, set the rated current I0, constant s, multiple x, coefficient y, average time probability a of high speed and high torque causing pump shaft abnormality, probability b of a single stall causing pump shaft abnormality, probability c of each sudden valve opening causing pump shaft abnormality, pump shaft abnormality probability threshold P0, set stall number n=0, number of sudden valve openings m=0, and high speed and high torque time t=0;

[0033] S2: Handle other tasks;

[0034] S3: Detect the current motor current I c And let the motor current before time T be I. T ;

[0035] S4: If I c If the value is greater than I0*x, then proceed to step S5; otherwise, proceed to step S6.

[0036] S5: The number of stall attempts n = n + 1, continue to execute step S10;

[0037] S6: If I c >I T If I0*y is obtained, then proceed to step S7; otherwise, proceed to step S8.

[0038] S7: The number of times the valve is suddenly opened is m = m + 1, then continue to execute step S10;

[0039] S8: If I c If I > 0, proceed to step S9; otherwise, proceed to step S10.

[0040] S9: Cumulative I c Time t when > I0 i High-speed, high-torque time t = t + t i Continue with step S10;

[0041] S10: According to the formula r=I c / (I0*s), calculate coefficient r; according to the formula p(g)=(1+r)*a*t, calculate the probability p(g) of pump shaft abnormality when high speed and high torque occurs; according to the formula p(d)=b*n, calculate the probability p(d) of pump shaft abnormality when stall torque suddenly changes; according to the formula p(f)=c*m, calculate the probability p(f) of pump shaft abnormality when the valve is suddenly opened.

[0042] S11: Calculate the pump shaft abnormality probability P according to the formula P = p(g) + p(d) + p(f);

[0043] S12: If P > P0, then the pump shaft is determined to be abnormal, and the process returns to step S2; otherwise, the pump shaft is determined to be normal, and the process returns to step S2.

[0044] The main external factors affecting pump shaft abnormalities are: 1. High torque at high speeds; 2. Sudden torque changes when stall occurs; 3. Sudden torque changes when the user suddenly opens the valve.

[0045] The constant s, multiple x, coefficient y, average time probability a of high speed and high torque causing pump shaft abnormality, probability b of a single stall causing pump shaft abnormality, probability c of each sudden valve opening causing pump shaft abnormality, and pump shaft abnormality probability threshold P0 were all obtained through experiments.

[0046] The time-average probability 'a' of pump shaft abnormalities caused by high speed and high torque refers to the reciprocal of the average time of breakage of multiple shafts under high speed and high torque operation.

[0047] High torque is measured by the motor's operating current. When the current reaches or exceeds the motor's rated current I0, it indicates high torque operation.

[0048] In actual operation, the greater the torque, the greater the impact on the pump shaft. Therefore, the formula for calculating the probability p(g) of pump shaft abnormality at high speed and high torque needs to include a coefficient r related to the current.

[0049] Stalled rotor is measured by current. When the current reaches more than x times the rated current (e.g., x=2.5), it indicates that a stalled rotor has occurred.

[0050] When a valve suddenly opens from a very small size to a very large size, it is represented by a sudden change in the driving current. If the current increases by more than the rated current * y (e.g., y = 20%) within a time period T, it indicates that the valve has suddenly opened.

[0051] In this embodiment, a=0.000001, b=0.0022, c=0.00012, s=150, and P0=0.3.

[0052] This invention determines the pump's status by monitoring the motor's current. It then calculates the probabilities of pump shaft abnormalities (p(g)) during high-speed, high-torque operation, (p(d)) during sudden changes in stall torque, and (p(f)) during sudden valve opening using formulas. Finally, it sums these probabilities and compares them with a pump shaft abnormality probability threshold (P0) to determine if the pump shaft is abnormal. This allows for prediction of pump shaft abnormalities and timely implementation of countermeasures to prevent serious consequences such as pump shaft breakage, mechanical damage, fluid leakage, and system failure.

[0053] Furthermore, in step S9, the cumulative I c Time t when > I0 i The timing is obtained through the timer built into the water pump controller.

[0054] The current detection method is as follows: In step S3, the motor current is detected in real time by a current sensor.

[0055] Figure 2 The diagram shows the circuit schematic. The IGBT drive section and the motor drive section are conventional circuits. U2 in the diagram is a current sensor, which can directly convert the current signal into a voltage signal suitable for processing by the microcontroller's ADC. The current sensor U2 can be a CC6920 Hall effect current sensor.

[0056] Furthermore, in step S12, when the pump shaft is determined to be abnormal, a warning signal is issued and the current pump shaft abnormality probability P value is sent to the user, who can handle it uniformly during equipment maintenance as appropriate.

[0057] Example 2: See Figure 3 , 4 :

[0058] This embodiment is basically the same as the structure of the first embodiment above. The main difference is that in step S3, the current of the motor is sampled by a current sampling resistor.

[0059] For applications with low drive current (e.g., drive current of only a few amperes), the circuit schematic is as follows: Figure 3 As shown, the motor current is sampled through a current sampling resistor RS with a large resistance value. Then, the current signal is converted into a voltage signal. The microcontroller processes the signal through its internal ADC function module to obtain the current of the motor.

[0060] For applications with large drive current, the circuit schematic is as follows: Figure 4 As shown, a current sampling resistor RS with a small resistance is used. The sampled signal is amplified by an operational amplifier and then sent to the microcontroller ADC for processing.

[0061] The above embodiments are merely one of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes made in accordance with the shape, structure and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A pump shaft abnormality detection method characterized by comprising: Comprising the following steps: S1: initialize the single-chip microcomputer, set rated current I0, constant s, multiple x, coefficient y, time average probability a of high-speed large torque causing pump shaft abnormality, probability b of single blocked rotation causing pump shaft abnormality, probability c of each sudden opening of large valve causing pump shaft abnormality, pump shaft abnormality probability threshold P0, set blocked rotation times n=0, sudden opening of large valve times m=0, high-speed large torque time t=0; S2: process other tasks; S3: detect the current motor current I c and record the motor current I before T time T ; S4: if I c > I0*x, then perform step S5; Otherwise, execute step S6; S5: blocked rotation times n=n+1, continue to execute step S10; S6: If I c > I T + I0*y, then perform step S7; Otherwise, execute step S8; S7: sudden opening of large valve times m=m+1, continue to execute step S10; S8: if I c > I0, then perform step S9; Otherwise, execute step S10; S9: cumulative I c time t at I0 i , high-speed large-torque time t = t + t i , continue to step S10; S1 0: according to the formula r=I c (I0*s), calculate the coefficient r; according to the formula p(g)=(1+r)*a*t, calculate the probability p(g) of pump shaft abnormality when high speed and large torque occurs; according to the formula p(d)=b*n, calculate the probability p(d) of pump shaft abnormality when the locked-rotor torque suddenly changes; according to the formula p(f)=c*m, calculate the probability p(f) of pump shaft abnormality when the valve is suddenly opened. S11: calculate pump shaft abnormality probability P according to formula P= p(g)+ p(d)+ p(f); S12: if P>P0, determine pump shaft abnormality and return to step S2; otherwise, determine pump shaft normality and return to step S2.

2. The pump shaft abnormality detection method according to claim 1, characterized by: In step S9, I is accumulated c Time t when I0 i Obtained by a timer built into the water pump controller.

3. The pump shaft anomaly detection method of claim 1, wherein: In step S3, the current of the motor is detected in real time through a current sensor.

4. The pump shaft anomaly detection method of claim 1, wherein: In step S3, the current of the motor is sampled through a current sampling resistor.

5. The pump shaft anomaly detection method of claim 1, wherein: In step S12, when pump shaft abnormality is determined, an alarm signal is sent out and the current pump shaft abnormality probability P value is sent to the user.

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