JPH09195919A - Back flow judging method for pumping machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting the operating point of a pumping machine and the allowance to the back flow range as dynamic characteristics. SOLUTION: The states of at least three elements out of water pressure H to be applied to a pumping machine, the pumping amount Q, input torque T, the rotational speed N, pump input P and the guide valve opening Y are detected (step S71), a coordinate system for taking at least two of three elements as a parameter is set, the operating point of the pumping machine is determined (step 72, 73) from the detected states, the back flow rushing position (step S75) specified by the coordinate system and the operating point of the pumping machine are compared with each other (step S76), and the allowance of the present operating point in relation to the back flow rushing position is judged (step S77).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the operation of a pump having a relatively large capacity, and more particularly to a method for determining a backflow for operating so that the backflow does not occur.

[0002]

2. Description of the Related Art It is known that a pump has a characteristic (a phenomenon) of backflow. The backflow characteristics are, for example, as shown in FIG. 4, when the horizontal axis is the pumping quantity Q and the vertical axis is the total head H or pump input P, as shown in FIG. 4, the pumping quantity Q−the total head H, the pumping quantity Q. -It is the characteristic that there is a minimum value in the relation of the pump input P. In FIG. 4, the total head H-
The backflow region Rw is on the left side from the maximum value Max in the characteristic of the pumped water amount Q, and on the left side from the minimum value Min in the characteristic of the pump input P-pumped water amount Q, which is the backflow region Rw.
From the viewpoint, the positions of the maximum value Max of the total head H and the minimum value Min of the pump input P coincide. When operating in this backflow region Rw, vibration and noise that are several times or more that of normal operation occur. Therefore, the pumping operation in the reverse flow region Rw imposes a burden on the pump and the attached machines including the pump may be damaged. Therefore, pumping operation is performed so as not to enter this backflow region.

In order to operate the vehicle without entering the backflow region, it is necessary to detect the backflow. A conventional backflow detection method is disclosed in, for example, Japanese Patent Publication No. 7-37791. , A method to detect that the pump is operating in the reverse flow area by detecting the vibration and noise that appear when it falls into the reverse flow area, and a decrease in pump input that appears when the pump is dropped into the reverse flow area It is known how to do it.

[0004]

However, these methods can detect whether or not the pump is falling into the backflow region, but can evaluate the risk of the pump falling into the backflow region, that is, the backflow region. I couldn't detect the margin until I fell into. Therefore, in the conventional technology, since it is detected that the reverse flow operation is started only after falling into the reverse flow region, the pumping machine itself is already in an abnormal operating state at that time, and there is a risk of damage. The pumping machine will be operated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for detecting a margin between an operating point of a pump and a reverse flow region as a dynamic characteristic.

[0006]

In order to achieve the above object, the present invention sets a coordinate system suitable for detecting the operating point of a pump and the margin to the backflow region, and sets the operating point of the pump. Detecting the signals necessary to fit the coordinate system,
Determine the operating point of the pump. Find the backflow entry position specified by the set coordinate system. Create an evaluation function that defines the margin until backflow entry based on the coordinate relationship between the operating point of the pump and the backflow entry position. The positional relationship between the two is also compared.

Specifically, the present invention detects the state of at least three of the water pressure applied to the pump, the pumping amount, the input torque, the rotation speed, the pump input, and the guide valve opening degree, and And a coordinate system having two of the three elements as parameters are set, the operating point of the pump is determined from the detected state, and the reverse flow plunge position and the operation of the pump defined by the coordinate system are set. It is characterized in that the margin for the current regurgitation position of the current operating point is determined by comparing with the point.

In this case, the element is selected from water pressure, pumping amount, input torque, rotation speed, pump input, and guide valve opening in the model pumping machine. The determination is performed by calculating the state of the actual machine from the elements detected based on the model pumping machine.

Further, the coordinate system is composed of a coordinate system in which the number of rotations of the model pumping machine is normalized and the amount of pumped water is used as a parameter. In this coordinate system, the determination is made as a backflow inrush position based on the amount of pumped water. This can be done based on the difference between the operating point or the difference between the backflow entry position as seen from the water level and the operating point.

Further, the coordinate system is composed of a pump input in which the number of rotations of the model pump is normalized and a coordinate system in which the pumping amount is used as a parameter, and in this coordinate system, the backflow entry position where the judgment is viewed from the pump input. And the operating point. When detecting the reverse flow entry position,
The guide valve opening is used as a parameter.

Further, the coordinate system is set by using the pump input and the water level as parameters without normalizing the rotation speed of the model pumping machine, and in this coordinate system, the above-mentioned judgment is viewed from the pump input and the backflow inrush position and the operating point are set. It can be performed based on the difference between the operating point and the backflow entry position as seen from the water level.

Further, the coordinate system is set by using the pumped water amount and the water level as parameters without normalizing the rotation speed of the model pumping machine, and in this coordinate system, the judgment is made from the pumped water amount and the backflow inrush position and the operation are determined. It can be performed based on the difference between the operating point and the backflow entry position as seen from the water level. The detection of the backflow inrush position is performed by using the guide valve opening degree or the rotation speed as a parameter. The determination of the margin is performed in real time according to the input from each element.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

1. First Embodiment <Outline Process of Backflow Margin Detection> FIG. 1 is a flowchart showing a general process procedure of backflow margin detection in the first embodiment of the present invention. In this processing procedure, first, the water pressure (total head) H applied to the pump, the pumping amount Q, the input torque T, the rotation speed N, and the guide valve opening Y are detected (step S1), and the backflow inrush position is model tested. Etc., and apply the operating point of the pump and the reverse flow entry position to the set coordinate system (steps S2, S3, S4),
The backflow margin is detected (step S
5).

The detection procedure when H is the total head will be described. In this process, first, the differential pressure of iron pipe water pressure-draft water pressure is obtained. In order to obtain the total head H, it is necessary to consider the velocity head from the differential pressure, and when the pumping amount Q is detected, the velocity head can be directly calculated.
When the pumped water amount Q is not detected, the pumped water amount Q may be estimated based on the differential pressure. As an example, FIG. 2 shows a processing procedure for estimating the total head.

In this processing procedure, first, as described above, the pressure difference between the iron pipe water pressure and the draft water pressure (iron pipe water pressure-draft water pressure) H is calculated (step S21), and the pressure difference H is regarded as the total head H '. ₁₀₀₀ is obtained (step S22). In addition, "'" of H'here shows the value when converting into a model base, and the subscript " ₁₀₀₀ " shows the rotation speed of a pump. Therefore, H1000 indicates the total head of the model pump (model) converted to ₁₀₀₀ rpm. And
Model-based 1000 rp created in advance
Graph of total head and pumped water at m (H ' ₁₀₀₀ -Q'
₁₀₀₀ graphs) reads the model-based pumping amount Q _'1000 from (step S23). In this way, the model-based total head Q _'1000 from below (3) read seek pumping amount Q based on the equation (step S24). When the estimated pumping rate is obtained in this way, the total head is determined in consideration of the velocity head calculated from the estimated pumping rate (step S25).

[0017] The total head H is, H = H + (1/2) - is obtained as ^{_{{(Q / A 1) 2}} (Q / A 2) 2} ... (1). Here, A ₁ indicates the cross-sectional area of the iron pipe water pressure measurement point, and A ₂ indicates the cross-sectional area of the draft water pressure measurement point.

The total head H thus obtained is substituted into step S22 again, and the subsequent processing is repeated to check whether H has converged to a certain value (step S2).
6) The converged value is used as the total head (step S27).

<Setting of Coordinate System> Next, setting of the coordinate system will be described. Coordinate systems can be roughly divided into model-based and actual machine-based. Furthermore, it is also divided depending on whether each is normalized by the rotation speed or not. These relationships are shown in FIG. Regarding the normalization of the rotation speed in the figure, the normalization at 1000 rpm is used as an example. In addition, as I touched on before, ""
Those with "" are model bases (measured with a model pump), and those without "'" are actual machine-based coordinate systems. That is, the coordinate system 31 'set on the model base is "H' _1000- " depending on whether the rotation speed is normalized (32 ') or not (33').
"Q ' ₁₀₀₀ coordinate system"34',"P' _1000- Q' ₁₀₀₀ coordinate system" 35 ', "P'-H' coordinate system" 36 'and "Q'
-H 'coordinate system "37', and the coordinate system 31 set on the basis of the actual machine is" H ₁₀₀₀ -Q "depending on whether the rotation speed is normalized (32) or not (33).
₁₀₀₀ coordinate system "34," P ₁₀₀₀ -Q ₁₀₀₀ coordinate system "35,
It is divided into a "PH coordinate system" 36 and a "QH coordinate system" 37.

<< H ' ₁₀₀₀ -Q' ₁₀₀₀ coordinate system >> where
H _'1000 -Q' ₁₀₀₀ - a (rams amount) coordinate system 34 'shown in FIG. 5 will be described with the detection of reverse flow inrush margin in normalized model-based coordinate system in this 1000 rpm.

The vertical axis represents water pressure _H'1000 , and the horizontal axis represents pumping volume Q '.
Taking ₁₀₀₀ and taking the locus of the operating point of the pump for a certain guide valve opening Y, a characteristic having an inflection point as shown in the figure can be obtained. A region where the pumped water amount Q ′ ₁₀₀₀ is smaller than the maximum point Max in the characteristic diagram, in other words, a region on the left side of the dotted line D ₁ is the backflow region Rw.

[0022] Q 'thinking ₁₀₀₀ axially back flow rush position Q' _c1000, the operating point of the water elevator 'is defined as _1000, the evaluation function regarding allowance of up to reflux (Q' Q ₁₀₀₀ -
If defined as _Q'c1000 ), it is possible to manage (evaluate backflow) with this size. In addition it can be determined that fell to the back flow if the Q _'1000 <Q' _c1000.

FIG. 6 shows what is considered in the _H'1000 axis direction in the same coordinate system. Backflow rush position Q by defining _'c1000, the operating point of the pumping unit H' ₁₀₀₀ and the evaluation function regarding allowance of up to reflux (H _'1000 -H ' _c1000 ) and can be managed (evaluate backflow) with this size. See you H '
_{If 1000} >_H'c1000, it can be determined that the flow has fallen into the backflow. However, when considering in the H ′ ₁₀₀₀ axis direction, there are a plurality of solutions in the section from the minimum value Min to the maximum value Max of the operation locus, for example, A as shown in the figure,
Since points B and C are considered, the operating point cannot be specified. B of these
Driving at the point is unstable and cannot be the driving point.
Therefore, points A and C are candidates for driving points, but Q '
₁₀₀₀ or P _'1000 data using the operating point of the can be easily identified. The operating point _H'1000 is the dotted line D ₁
If it is on the left side, the operating point is in the backflow region, so the definition of the margin does not hold.

Here, the processing for determining the operating point in accordance with the above characteristics will be described with reference to the flowchart of FIG.

In order to specify the operating point, one or two of the pumped water amount Q, the water level (water pressure) H, and the pump input P (actually, the torque T is detected) must be detected. Theoretically, as shown as step S71, the pumped water amount detecting means detects the pumped water amount Q.

The water level H is detected by the water level (water pressure) detecting means.

The water level H and the pumped water amount Q are detected by the water level (water pressure) detecting means and the pumped water amount detecting means.

The water level (water pressure) detecting means and the pump input (or torque) detecting means detect the water level H and the pump input P (or torque T).

There are four possible detection cases.

In the case of (1), that is, when the water level H is detected and the operating point is calculated, a. Start the backflow margin detection from the steady pumping operation (the area to the right of the backflow entry position), b. The processing is canceled when placed in the left region (the backflow region) than backflow rush position of if limiting the two points (i.e., using only the linear part of the H _'1000 -Q' ₁₀₀₀ curve), the operating point Since the operating point can be determined even in the case where there are three solutions, the backflow margin can be detected.

[0031] of the case, ie, in the case of detecting a back flow margin by detecting the pumping amount, the backflow rush position Q _'1000
Set it on the base, and in the cases of to, set the backflow entry position on the _H'1000 base. In this case, that is, in the case where the backflow margin is detected by detecting the water level and the amount of pumped water, it is possible to set the _Q'1000 base. In this way, when the above parameters are detected by any of the above-mentioned means, step S7 is carried out in consideration of the number N of rotations of the water pump detected in step S72.
At 3, the operating point is calculated. The calculated operating point depends on the guide valve opening Y detected in step S74.
Is compared with H is called on a 75 _'1000 -Q' backflow rush position data and step S76 of ₁₀₀₀ coordinate system margin is detected with respect to inrush position to reflux (step S77).
It should be noted that this detection can be carried out in real time when the necessary parameters are fetched.

[0032] "P _'1000 -Q' ₁₀₀₀ coordinate system" P _'1000 -
Q _'1000 - a (pump input pumping amount) coordinate system shown in FIG. 8,
The detection of the backflow entry margin in the model-based coordinate system normalized at 1000 rpm will be described.

[0033] take the ₁₀₀₀ to the vertical axis P 'Q _1000, the horizontal axis',
The characteristic as shown in the figure can be obtained by taking the locus of the operating point of the pump for a certain guide valve opening Y. The backflow region Rw is on the left side of the dotted line D ₂ . P 'think ₁₀₀₀ axially back flow inrush position P' _c1000, 'by defining ₁₀₀₀ a, evaluation of margin to reflux function (P' the operating point of the water elevator P ₁₀₀₀ -
_P'c1000 ) and can be managed with this size. In addition, it can be determined that fell to the back flow if the P _'1000 <P' _c1000.

However, when considering the _P'1000 axis direction,
There are a plurality of solutions in the section from the minimum value Min to the maximum value Max of the driving locus, and, for example, A, B, and
The C point is considered and the operating point cannot be specified. Of these, driving at point B is unstable and cannot be the driving point. Therefore, A point, but the point C becomes a candidate of the operating point, it is possible to easily determine the operating point using the data of the Q _'1000 or H' _1000. If the operating point is on the left side of the dotted line D ₂ , the definition of the margin does not hold because it is the backflow region Rw.

Here, the processing for determining the operating point corresponding to the above characteristics will be described with reference to the flowchart of FIG.

In order to determine the operating point, one or two of the pumping quantity Q, the water level H, and the pump input P (actually, the torque T is detected) must be detected as described above. Theoretically, as shown as step S91, the pumped water amount detecting means detects the pumped water amount Q.

The pump input (or torque) detecting means detects the pump input P (or torque T).

The pump input (or torque) and the pumped water amount detecting means detect the pump input P (or torque T) and the pumped water amount Q.

The water level H and the pump input P (or torque T) are detected by the water level (water pressure) detecting means and the pump input (or torque) detecting means.

There are four possible detection cases.

The case, i.e., when detecting pump input P (or torque T) by a pump input (or torque) detecting means, the aforementioned H _'1000 -Q'
₁₀₀₀ coordinate system 34 may mean, the limitation of using only the linear part of the 'case as well as P' ₁₀₀₀ -Q _'1000 curve. For, i.e., in the case of detecting the pumping amount Q by pumping amount detecting means sets a backflow rush position Q 'in ₁₀₀₀ based. In case of ~, set the reverse flow entry position to _P'1000
Set at the base. Incidentally, the case, i.e., when detecting pump input P (or torque T) and pumping amount Q by pump input (or torque) and pumping amount detecting means, it is possible to set at Q _'1000 base . If the above parameters are detected by any of the above means and step S9, step S9
The operating point is calculated in step S93 in consideration of the number N of rotations of the water pump detected in 2. Calculated operating point is compared with P _'1000 -Q' ₁₀₀₀ backflow rush position data and step S96 of the coordinate system that is called in step S95 in accordance with the detected guided valve opening Y in step S94, the reverse flow The margin for the entry position is detected (step S97).

<<P'-H'Coordinate System >> The P'-H' (pump input-water level) coordinate system is shown in FIG. 10, and the detection of the backflow inrush margin in the model-based coordinate system not normalized by this rotation speed is shown. explain. The figure is an example of the characteristics of the variable speed pumping machine.

When P'is plotted on the vertical axis and H'on the horizontal axis, the operating point E is represented by a trapezoid, and the backflow entry position is represented by the line segment D ₃ . In this case, the lower part of the reverse flow entry position D ₃ is the reverse flow region Rw.
It is. In the P'-H 'coordinate system, the concept of margin is planar, so some evaluation functions can be defined. As an example, the total head H'on the horizontal axis is fixed and only the pump input P'direction is considered. If the backflow entry position is defined as P'c and the operating point of the pump is defined as P ', the evaluation function can be defined as (P'-P'c) and can be managed with this size. Similarly, pump input P '
When the water level is H ', the backflow entry position is H'c, and the operating point of the pump is H', the evaluation function can be defined as (H'-H'c). Can be managed with. Further, by comparing P'and P'c and H'and H'c, it is possible to determine the backflow drop.

When plotting the relationship between N (rotation speed) and Y (guide blade opening) on the P'-H 'coordinate, the characteristic generally becomes as shown in FIG. Therefore, in order to specify the operating point, the pump input P, the water level H, the rotation speed N, and the guide valve opening Y
Any two of them will be detected, and processing will be performed based on the detected parameters. The processing procedure is shown in the flowchart of FIG. 12 and will be described with reference to this flowchart.

In this processing procedure, first, P, H, N, Y
Any two of them are detected (step S1201).
Theoretically, the pump input (or torque) detecting means and the water level (water pressure) detecting means detect the pump input P (or torque T) and the water level H.

The pump input (or torque) detecting means and the rotational speed detecting means detect the pump input P (or torque T) and the rotational speed N.

The pump input (or torque) detecting means and the guide valve opening degree detecting means detect the pump input P (or torque T) and the guide valve opening degree Y.

The water level H and the rotation speed N are detected by the water level (water pressure) detection means and the rotation speed detection means.

The water level (water pressure) detecting means and the guide valve opening degree detecting means detect the water level H and the guide valve opening degree Y.

The rotation speed N and the guide valve opening Y are detected by the rotation speed detecting means and the guide valve opening detecting means.

There are six types of detection cases.

Then, the operating point is calculated from the parameter detected by any of these (step S120).
2). On the other hand, at least three kinds of setting methods can be considered as the backflow entry position. For example, in the case of detecting the pump input P and the water level H, a. Set on P'base (fixed to H ') b. Set on H'base (fixed at P ') c. The distance is calculated from P'and H'and there are three settings. The backflow inrush position data set in this way (step S1203) is compared with the operating point calculated in step S1202 in step S1204 to detect a margin for the backflow inrush position (step S12).
05).

<Q'-H 'Coordinate System> FIG. 13 shows the Q'-H' (pumping-water level) coordinate system, and the detection of the backflow rush margin in the model-based coordinate system which is not normalized by this rotation speed. explain. The figure is an example of the characteristics of the variable speed pumping machine.

When the vertical axis is Q'and the horizontal axis is H ', the operating point F is represented by the region as shown in the figure. The backflow entry position is line segment D
Represented by ₄ . The lower part of the reverse flow entry position D ₄ is the reverse flow region Rw.
It is. In the Q'-H 'coordinate system, the concept of margin is planar, so some evaluation functions can be defined. As an example, the water level H ′ is fixed and only the pumped water amount Q ′ direction is considered.
If the backflow entry position is defined as Q'c and the operating point of the pump is defined as Q ', the evaluation function can be defined as (Q'-Q'c) and can be managed with this size. Similarly, the amount of pumped water Q'is made constant and only the direction of the water level H'is considered. If the backflow entry position is defined as H'c and the operating point of the pump is H ', the evaluation function is (H'-H'
It can be defined as c) and can be managed with this size. Also, Q '
And Q'c, and H'and H'c are compared, it is possible to determine the depression in the backflow.

FIG. 14 is a plot of the relationship between N (rotational speed) and Y (guide blade opening) on the Q'-H 'coordinate. Therefore, in order to determine the operating point, any two of the pumped water quantity Q, the water level H, the rotation speed N, and the guide valve opening Y are detected, and the processing is performed based on the detected parameters. The processing procedure is shown in the flowchart of FIG.
This will be described with reference to this flowchart.

In this processing procedure, first, Q, H, N, Y
Any two of them are detected (step S1501).
Theoretically, the pumped water quantity Q and the water level are detected by the pumped water quantity detecting means and the water level (water pressure) detecting means.

The pumped water amount Q and the rotational speed N are detected by the pumped water amount detecting means and the rotational speed detecting means.

The pumped-up amount Q and the guide valve opening Y are detected by the pumped-up amount detecting means and the guide valve opening detecting means.

The water level H and the rotation speed N are detected by the water level (water pressure) detection means and the rotation speed detection means.

The water level H and the guide valve opening Y are detected by the water level (water pressure) detecting means and the guide valve opening detecting means.

The rotation speed N and the guide valve opening Y are detected by the rotation speed detecting means and the guide valve opening detecting means.

There are six types of detection cases:

Then, the operating point is calculated from the parameter detected by any of these (step S150).
2). On the other hand, at least three kinds of setting methods can be considered for the backflow entry position. For example, in the case of detecting Q and H, a. Set based on Q '(fixed at H') b. Set based on H '(fixed at Q') c. There are three settings, the distance calculated from Q'and H '. The backflow inrush position data set in this way (step S1503) and the operating point calculated in step S1502 are compared in step S1404 to detect a margin for the backflow inrush position (step S15).
05) In these cases, the water level (water pressure) H
The detection of: a. Detect the total head.

B. Detect the total head.

There are two possible cases. When detecting the total head, it is sufficient to detect the iron pipe water pressure and the draft water pressure, and to estimate the total head according to the flow chart shown in Fig. 2. When detecting the total head, The pond water level is detected, and the total head is calculated by total head = upper pond water level-lower pond water level. Not surprisingly, FIG.
Further, in the processing based on the flowchart of FIG. 15, there are a total head-based processing and a total head-based processing, and it is necessary to correspond to the water level being considered.

Although the model-based coordinate system has been described above, the same discussion can be made for the actual machine-based coordinate system.

That is, the following equation is used to correspond the model base to the actual machine base.

H = H ′ ₁₀₀₀ × MR ² × (N / 1000) ² × √ (η _pmax / η ′ _pmax ) ... (2) Q = Q ′ ₁₀₀₀ × MR ³ × (N / 1000) × √ (η _pmax / _η'pmax ) (3) P = P ' ₁₀₀₀ × MR ⁵ × (N / 1000) ³ × (γ / 1000) (4) where MR: model ratio η _pmax : maximum efficiency of actual pumping machine _η'pmax : Maximum efficiency of model (model) pumping machine γ: Specific weight N: Rotational speed Therefore, if the water level H ', pumping volume Q', and pump input P'are known in the model (model), the total head H of the actual machine , The pumped water amount Q and the pump input P can be easily known.

[Second Embodiment] In the first embodiment, the backflow margin is detected, but instead of this structure, it may be configured to determine whether or not the backflow has dropped. This processing procedure is shown in FIG. In this process, instead of the process for detecting the backflow margin in FIG. 1, that is, in place of step S5, a process for determining whether or not the backflow has dropped is performed (step S6). In this processing, as in the first embodiment, the relationship between the backflow entry position and the operating point is not checked, but only whether or not the operating point is in the backflow region is determined. In addition, since each procedure and detection method not particularly described are configured in the same manner as in the first embodiment, description thereof will be omitted.

[0070]

As is apparent from the above description, according to the present invention, it is possible to detect the operating point of the pump and the margin up to the reverse flow region as a dynamic characteristic. As a result, the operation state can be easily grasped, and it is possible to perform processing before falling into the backflow region and control so that the backflow operation is not performed, and as a result, an accident can be prevented.

Further, since it is possible to detect the margin up to the backflow region, the behavior of the pumping machine to the backflow region and the operating point of the pump when it is operated by an external command, and other units in the water pump that share the pipeline. It is possible to add a quantitative evaluation to the behavior of the pumping machine up to the operating point and the backflow region due to the disturbance from. As a result, it is possible to execute highly accurate backflow inrush avoidance control.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing procedure of backflow margin detection according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for estimating the total head.

FIG. 3 is a diagram showing types and classifications of set coordinates.

FIG. 4 is a diagram showing characteristics of a backflow phenomenon.

FIG. 5 is an explanatory diagram for determination of a backflow margin based on Q ′ ₁₀₀₀ in an H ′ ₁₀₀₀ −Q ′ ₁₀₀₀ coordinate system.

FIG. 6 is an explanatory diagram for determination of a backflow margin based on H ′ ₁₀₀₀ in an H ′ ₁₀₀₀ −Q ′ ₁₀₀₀ coordinate system.

FIG. 7 is a flowchart showing a processing procedure for determining a backflow margin in the H ′ ₁₀₀₀ −Q ′ ₁₀₀₀ coordinate system.

FIG. 8 is an explanatory diagram for determination of a backflow margin based on P ′ ₁₀₀₀ in a P ′ ₁₀₀₀ −Q ′ ₁₀₀₀ coordinate system.

FIG. 9 is a flowchart showing a processing procedure for determining a backflow margin in a P ′ ₁₀₀₀ −Q ′ ₁₀₀₀ coordinate system.

FIG. 10 is an explanatory diagram for determination of a backflow margin in a P′-H ′ coordinate system.

FIG. 11 is a diagram showing a relationship between a rotation speed and a guide plate opening in a P′-H ′ coordinate system.

FIG. 12 is a flowchart showing a processing procedure for determining a backflow margin in a P′-H ′ coordinate system.

FIG. 13 is an explanatory diagram for determining a backflow margin in the Q′-H ′ coordinate system.

FIG. 14 is a diagram showing a relationship between a rotation speed and a guide plate opening in a Q′-H ′ coordinate system.

FIG. 15 is a flowchart showing a processing procedure for determining a backflow margin in the Q′-H ′ coordinate system.

FIG. 16 is a flowchart showing a processing procedure for backflow drop determination in the second embodiment.

[Explanation of symbols]

H Total pumping height of actual pumping machine Q Pumping amount of actual pumping machine P Pump input of actual pumping machine N Rotation speed Y Guide valve opening T Torque H ₁₀₀₀ Total pumping head of actual pumping machine converted to ₁₀₀₀ rpm Q ₁₀₀₀ Converted to ₁₀₀₀ rpm Pumped volume of actual pump P ₁₀₀₀ Pump input of actual pump converted to ₁₀₀₀ rpm H'Total pump head of model pump Q'Pump of model pump P'Pump of model pump H'1000 Converted to ₁₀₀₀ rpm total head Q in is the model water elevator total head Q _'1000 1000 rpm in terms have been model pumping machine pumping quantity P' ₁₀₀₀ 1000 rpm in terms has been a model water elevator backflow rush position of the pump input H'c model pumping machine of 'c Pumping volume at the reverse flow entry position of the model pumping machine P'c Pump input at the reverse flow entry position of the model pumping machine H'c ₁₀₀₀ Model pumping machine converted to ₁₀₀₀ rpm Pumping amount at the reverse flow plunge position of the model pumping machine converted to P'c _{1000 1000} rpm. Total pumping height at the reverse flow plunge position of Q'c _{1000 1000} rpm.

Claims (17)

[Claims] 1. A backflow determination method for a pump, which determines an operating state with respect to a backflow generation point of the pump, comprising: a water pressure applied to the pump, a pumping amount, an input torque, a rotation speed, a pump input, and a guide valve opening degree. Detecting a state of at least three of the elements, setting a coordinate system having two of the at least three elements as parameters, and determining an operating point of the pump from the detected state, A backflow determining method for a water pump, comprising: comparing a backflow inrush position defined by a coordinate system with an operating point of the pump to determine a margin of the operating point with respect to the backflow inrush position. 2. The element is water pressure in a model water pump,
The backflow determination method for a pump according to claim 1, wherein the pumping amount, input torque, rotation speed, pump input, and guide valve opening degree are selected. 3. The backflow determination method for a pump according to claim 1, wherein the determination is performed by calculating a state of an actual machine from the elements detected based on a model pump. 4. The backflow determination method for a water pump according to claim 1, wherein the coordinate system comprises a coordinate system having parameters such as a water level and a pumping amount obtained by normalizing the number of revolutions of the model water pump. 5. The backflow determination of the pumping machine according to claim 4, wherein the determination of the margin for the backflow inrush position of the operating point is performed based on the difference between the backflow inrush position and the operating point viewed from the pumping amount. Method. 6. The backflow determination method for a pump according to claim 4, wherein the determination of the margin for the backflow inrush position of the operating point is performed based on the difference between the backflow inrush position viewed from the water level and the operating point. . 7. The backflow determination method for a water pump according to claim 1, wherein the coordinate system includes a pump input that normalizes the number of revolutions of the model water pump and a coordinate system that has a pumping amount as a parameter. 8. The backflow determination of a pumping machine according to claim 7, wherein the determination of the margin with respect to the backflow inrush position of the operating point is performed based on the difference between the backflow inrush position as seen from the pump input and the operating point. Method. 9. The detection of the backflow entry position is performed using a guide valve opening as a parameter.
The backflow determination method for a water pump according to any one of 6 and 8. 10. The backflow determination method for a water pump according to claim 1, wherein the coordinate system is set using the pump input and the water level as parameters without normalizing the rotation speed of the model water pump. 11. The backflow determination of a pumping machine according to claim 10, wherein the margin of the operating point with respect to the backflow inrush position is determined based on the difference between the backflow inrush position viewed from the pump input and the operating point. Method. 12. The backflow determination method for a pump according to claim 10, wherein the margin of the operating point with respect to the backflow entry position is determined based on the difference between the backflow entry position viewed from the water level and the operating point. . 13. The backflow determination method for a pump according to claim 1, wherein the coordinate system is set by using the pumping amount and the water level as parameters without normalizing the rotation speed of the model pump. 14. The backflow determination of a pumping machine according to claim 13, wherein the margin of the operating point with respect to the backflow inrush position is determined based on the difference between the backflow inrush position and the operating point as seen from the pumping amount. Method. 15. The backflow determination method for a pump according to claim 13, wherein the margin of the operating point with respect to the backflow entry position is determined based on the difference between the backflow entry position seen from the water level and the operating point. . 16. The backflow of the pumping machine according to claim 11, wherein the detection of the backflow inrush position is performed by using a guide valve opening degree or a rotation speed as a parameter. Judgment method. 17. The determination of the margin is performed in real time, as set forth in claim 1, 5, 6, 8, 11,
The backflow determination method for a pump according to any one of 12, 14, and 15.