JPS63138193A - Pump operating condition monitor - Google Patents

Abstract

PURPOSE:To obtain sure monitoring of the pump operating condition, by judging the pump operating condition after comparing detected values on the discharge pressure, suction pressure, flow rate, and pump shaft power with the set values for the normal operation. CONSTITUTION:The detected signals from a discharge pressure detector 12, a shaft power detector 13, a suction pressure detector 14, and a suction flow rate detector 15 are input into a judgement device 16. The judgement device 16 compares the signals input from respective detectors 12-15 with the corresponding set signals for the normal operation of the pump. Thus, all the condition-values concerning the operating condition of the pump can be compared, taking their interrelation into account. As a result, the abnormal operating condition of the pump can be detected without fail.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a monitoring device for monitoring the operating state of a water pump.

(Prior art) In general, the operating condition of a water pump can be determined by the actual pump stroke, pump flow rate, pump shaft power, pipe resistance, etc., and the correlation between these can be expressed as a curve as shown in Figure 3. It has become.

FIG. 3 shows the relationship between the pump flow rate Q1 on the horizontal axis and the pump actual stroke H and pump shaft power on the vertical axis. Curve 1 shows the relationship between Q and H and is called a Q-H characteristic curve, and curve 2 shows the relationship between Q and L.

The pipe line resistance R caused by the installation state of the pump changes depending on the flow rate flowing in the pipe line. Curve 3 shows the relationship between Q and R.

The intersection of these curves 3 and 1 is the pump operating point (pump operating point), and the normal pump operating state values are the pump flow rate q1, the pump actual lift, and the pump shaft power g.

FIG. 4 shows an operating characteristic curve when pump performance deteriorates due to wear of the pump blades and bushings.

When the performance of the pump deteriorates, the Q-H characteristic curve decreases compared to curve 1 during normal operation, as shown by the solid line. The pump operating point in this case is l'11. Qt is 47. Also,
The shaft power for outputting the flow aq during normal operation is gl, and the QL characteristic increases compared to curve 2 during normal pump operation, as shown by the solid line. As a result, at the pump operating point when pump performance deteriorates, the shaft power remains constant and the flow rate and actual stroke decrease.

Furthermore, when attempting to obtain q during normal operation, the shaft power is g1 and the actual stroke is h1'.

To summarize these phenomena, when the pump performance deteriorates, the pump Q-H-11) characteristics are that the flow rate and actual stroke decrease,
It is characterized by an increase in shaft power.

FIG. 5 shows the operating characteristic curve of the pump when the resistance of the pipe increases due to scale buildup in the pipe or clogging of the strainer.

When the pipe resistance increases, the pipe resistance curve increases compared to curve 3 during normal operation, as shown by the solid line.

Assuming that the performance of the pump is normal, the operating characteristic curves 1 and 2 of the pump do not change. The operating point of the pump in this case is q2. h2' Ω2. As a result, at the pump operating point when the pipe resistance increases, the flow rate decreases, the actual stroke increases, and the shaft power decreases.

FIG. 6 shows the operating characteristic curve of the pump when the resistance of the pipe decreases due to wear of the pipe or leakage of the pipe.

When the pipe resistance decreases, the pipe resistance curve decreases compared to curve 3 during normal operation, as shown by the solid line.

Assuming that the performance of the pump is normal, the operating characteristic curves 1 and 2 of the pump do not change. In this case, the pump operating point is q
It becomes 3”3”3. As a result, at the pump operating point when the pipe resistance decreases, the flow rate increases, the actual stroke decreases, and the shaft power increases.

As described above, various characteristics appear on the pump operation characteristics at the pump operation point depending on the operation state of the pump, and when these characteristics are organized, a matrix as shown in Table 1 is obtained.

Table 1 (Problems to be Solved by the Invention) Conventionally, in order to monitor whether a pump is operating in a normal state, it has been necessary to measure vibrations of the pump and determine whether there is an abnormality. It is. However, this has the disadvantage that it cannot be determined unless an abnormality occurs in the pump.

Furthermore, state values such as pump discharge pressure and suction flow rate are detected, and the operating state of the pump is monitored based on the detected values. However, this monitoring means only monitors the operating state value and limit value, and cannot monitor changes in the operating state.Furthermore, there is an increase in loss due to scale build-up in the pipes, and the pump blades and bushings. The drawback was that it was difficult to detect performance deterioration due to wear and other factors.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a monitoring device that detects all of the above-mentioned status values regarding the operating status of a pump, grasps the correlation between them, monitors the operating status in real time, and determines changes over time. It's about doing.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a detector capable of detecting each of discharge pressure, suction pressure, flow rate and pump shaft power during operation of a pump, and a detector capable of detecting these. The present invention is characterized by comprising a determination device that determines the operating state of the pump by comparing a value detected by the pump with a set value during normal operation of the pump.

(Function) According to the present invention, the discharge pressure, suction pressure, flow rate, and pump shaft power are always detected during pump operation, and these detected values are compared with the set value during normal pump operation to determine the pump operating status. be judged. Therefore, if there is any abnormality in the pump, it can be known in advance, and appropriate measures can be taken depending on the type of abnormality.

(Embodiment) Hereinafter, an embodiment of a pump monitoring device according to the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 11 indicates a pump for water supply, and this pump 11 is configured to forcefully transport water from the suction pipe 8 side to the discharge pipe 9 side. The discharge pipe 9 has a discharge pressure detector 12 that detects the discharge pressure of the pump 11, the pump 11 (this is a shaft power detector 13 that detects the shaft power), and the suction pipe 8 has a discharge pressure detector 12 that detects the discharge pressure of the pump 11. A suction pressure detector 14 for detecting the suction flow rate and a suction flow rate detector 15 for detecting the suction flow rate are connected.On the other hand, each of the above-mentioned detectors 12, 13.
14.15 is connected to the judgment device 16, and this judgment device 1
6 monitors the operating state of the pump 11 based on detection signals from the respective detectors 12, 13, 14 and 15. Although this embodiment is configured to detect the flow rate on the suction pipe 8 side, it is also possible to configure the flow rate to be detected on the discharge pipe 9 side.

Next, the present invention will be explained in detail.

The judgment device 16 detects the detected values of pump flow, actual stroke, and shaft power inputted from each detector 12, 13, 14, and 15, and Q, H, and L at the pump operating point measured at the time of pump installation.
(Or the same Q when designing a pump.

H, L) is compared with the reference value determined based on the reference value.

The results of this comparison are compared with the matrix in Table 1 to determine the pump operating status. Note that the above actual stroke is the value obtained by subtracting the suction pressure from the discharge pressure.

FIG. 2 shows a flowchart for executing the above-described process. Note that R1 to R9 in the figure indicate each step of the flowchart.

In step R, suction pressure P 1 discharge pressure P2, suction flow *
The detected values of q and shaft power g are manually input, and in step R, Pl is subtracted from Pl in order to calculate the actual distance.

In step R4, the reference value Q and the detected flow mq are compared, and if Q>q, the value 5 is stored in the register A.
<q, the value 0 is input to register A.

In step R5, H, which is a reference value, is compared with the detected actual degree. If H>h, a value 3 is input to register B, and if H<h, a value O is input to register B.

In step R6, the detected shaft power ρ becomes the reference value.
are compared, and if L>g, the value 2 is stored in register C, and Lu
At l+, the value 0 is input to register C.

In step R7, the values in registers A, B, and C are added, and this total value is input to register p.

The value in this register D indicates the operating state of the pump.

In step R8, the value in register D is determined. That is, when the value of register D is 9 or 0, it corresponds to case 1 shown in Table 1 above, and it is determined that the pump is normal but the system is abnormal. However, q, hl
! If it is the same as Q, H, and L, it is determined that the pump is normal.

If the value of register D is 6, this corresponds to case 3, and it is determined that the pipe resistance has decreased (pipe leak).

If the value of register D is 3, it corresponds to case 4, and it is determined that the pipe resistance has increased (pipe scale adhesion).

If the value of register D is 1, this corresponds to case 5, and it is determined that the performance has deteriorated. The value in register D is 9°6.3,1
．． If it is other than 0, it corresponds to Case 2 and is determined to be a pump abnormality or a detector abnormality. In step R9, the results determined through such processing are displayed on a CRT or printed on a typewriter.

In addition, in a variable speed pump that controls the flow rate by changing the rotation speed of the pump, Q-H is calculated using the rotation speed as a parameter.
By determining the characteristic curve, applications similar to those described above become possible.

In addition, the shaft power can be substituted by measuring and converting the motor current in the case of a motor-driven pump, the steam control valve opening in the case of a turbine-driven pump, the turbine flow rate steam amount, and the steam condition. .

〔Effect of the invention〕

According to the monitoring device of the present invention, the actual stroke, flow rate, and shaft power during actual operation can be compared while correlating with the flow rate, actual stroke, and shaft power during normal operation of the pump as a reference. Abnormal operating conditions can be reliably monitored, and by monitoring and making judgments in real time, the pump can be stopped before large losses occur.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the monitoring device according to the present invention, Fig. 2 is a processing flowchart of the monitoring device, Fig. 3 is a diagram showing a pump operating characteristic curve, and Fig. 4 is a diagram showing pump performance deterioration. FIG. 5 is a diagram showing the operating characteristic curve when the pipe resistance increases, and FIG. 6 is a diagram showing the operating characteristic curve when the pipe resistance decreases. DESCRIPTION OF SYMBOLS 1... Pump line resistance curve, 2... Pump line resistance curve, 3... Pump line resistance curve, 11... Pump, 12... Discharge pressure detector, 13... Axis Power detector, 14... Suction pressure detector, 15... Suction flow rate detector, 16... Judgment device. Applicant's agent Mr. Sato Figure 1 Figure 2

Claims (1)

[Claims] Detectors that can detect discharge pressure, suction pressure, flow rate, and pump shaft power during pump operation, and compare the values detected by these detectors with the set values during normal pump operation to operate the pump. 1. A pump operating state monitoring device comprising: a determining device for determining a state.