JP2673734B2 - Pump operating status detection method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for detecting the operating status of a pump.

[Conventional technology]

For example, as a bearing for a vertical shaft pump, a ceramic bearing, which is lubricated and cooled by self-pumping water and can continue stable operation, is adopted.

In this type of bearing, the dry operation is performed for a very short time immediately after the start of the pump, and after this short time elapses, lubrication and cooling are immediately performed by the self-lifting water, and stable operation is started. That is, in the ceramic bearing, the dry operation is limited to a short time.

On the other hand, with the rapid progress of urbanization, the inflow of rainwater to pumping stations installed in waterways is becoming large and rapid. In such a situation, even if the water level of the suction well at the pumping station drops below the pumping cutoff level of the vertical pump, the dry operation is continued and the preceding standby operation or air management operation that precedes the operating state of the pump is performed. It is handled by doing.

In the vertical shaft pump used for the preceding standby operation and the air management operation, the dry operation will be continued for a long time,
During this time, lubrication water is not supplied to the bearing. Therefore, it has not been possible to adopt a ceramic bearing having a dry operation time limited to a short time for a vertical shaft pump that performs the preliminary standby operation or the air management operation.

As a means for solving such a problem, it is possible to supply lubricating water from the outside to the bearing, but in this case it is not possible to continue supplying the lubricating water from the outside even during pumping operation. Is the meaning. Therefore, a method of supplying lubricating water to the bearing is adopted by measuring the water level of the water absorption well, and when the water level falls to a predetermined water level, that is, a water level lower than the pumping start water level of the vertical shaft pump. It had been.

[Problems to be solved by the invention]

However, in this way, in the method of supplying lubricating water to the bearing based on the water level of the water intake well, it is necessary to consider the case where the water surface of the water intake well is calm and the case where the water surface of the water well is undulating. Considering the case of standing, it was necessary to set the supply level of lubricating water to a high level with a margin.

However, according to such a control method, when the water surface is relatively calm, the lubricating water is supplied even during the pumping operation. In other words, it is not possible to accurately know the operating status of the pump, and therefore, the useless supply of lubricating water is continued for a long time, and it was not possible to prevent the useless injection of water to the bearing.

The present invention has been made in view of the above circumstances,
A method of detecting the operating status of a pump, which can accurately detect the pumping operation or the air operation and the pump discharge amount by using a low-cost detecting means regardless of the water surface condition of the intake well. Is intended to provide.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a transmission shaft that transmits the output of a prime mover to a pump, and first and second detected objects that are slits spaced apart in the axial direction. First with parts
And a second disc, and by irradiating the first and second discs with light, the times for which the light is transmitted to the first and second detected portions are detected, and the first and second detection signals are detected. By providing optical first and second detectors for outputting the lap times or phases of the first and second detection signals by the first and second detectors and comparing them with a predetermined value. It is characterized by detecting whether it is a pumping operation or an aerial operation and detecting the discharge amount of the pump.

[Operation] According to the present invention, during pumping operation, which is a high load operation, the shaft power of the pump is large and twist occurs in the transmission shaft that transmits the output of the prime mover to the pump, whereas it is a low load operation. During air operation, the shaft power of the pump is small and the transmission shaft does not twist. Paying attention to the fact that the twist of the transmission shaft varies between the pumping operation and the air operation, the first and second twists are provided so as to be separated from each other in the axial direction of the transmission shaft.
Use of a rotational speed detection device for a shaft or a high-frequency pulse light source required for torque measurement by detecting by comparing a lap time or a phase, which is a detection signal by each of the optical detection means, with a preset predetermined value. It is possible to accurately detect whether the pumping operation or the air operation is being performed, regardless of the water surface condition of the water intake well, while keeping the cost low by eliminating the need for a pump shaft. Since the power and the discharge rate have a constant relationship depending on the pump type and installation conditions, knowing the characteristics of the pump in advance will allow the discharge rate of the pump to be accurately detected and the overall operating status of the pump to be determined. It is possible to grasp accurately.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a vertical shaft pump to which the present invention is applied, in which the main shaft 2 of the vertical shaft pump 1 is a bearing 5 fixed to the base of a guide vane 4 above an impeller 3 and a floor surface 7 of an intake well 6.
Is rotatably supported by a bearing 8 fixed at substantially the same height level as, and is rotationally driven by a prime mover 10 such as a motor or an engine.

Each of the bearings 5 and 8 is formed of ceramics such as silicon carbide,
Is supplied with lubricating water for lubrication and cooling.

The lubricating water supply system 9 includes a lubricating water supply source 9A, a pipeline 9B for supplying lubricating water from the lubricating water supply source 9A to the bearings 5 and 8, and a solenoid valve or an electric ball installed in the pipeline 9B. It is composed of a valve 9C such as a valve. Therefore, when the valve 9C is opened, lubricating water is supplied to the bearings 5, 8 from the lubricating water supply source 9A, and when the valve 9C is closed, the supply of lubricating water to the bearings 5, 8 is stopped.

The transmission shaft 14 for transmitting the output of the prime mover 10 to the main shaft 2 of the pump 1 has a first disc 16 having a first detected portion 15 made of a slit and a second detected portion 17 made of a slit. The second disc 18 and the second disc 18 are provided apart from each other in the axial direction of the transmission shaft 14.

The first and second detected parts 15 and 17 are respectively provided with
The first and second detectors Ca and Cb are provided so as to face each other. The first and second detectors Ca and Cb detect the first and second detected parts 15 and 17, respectively, and are, for example, reflection type optical sensors integrally provided with a light projector and a light receiver. . The first and second detectors Ca and Cb are the transmission shaft 1
When the transmission shaft 14 is rotating in a state where no load is applied to 4, the first and second detection target parts 15 and 17 are respectively detected.
Are simultaneously detected, and output the first and second detection signals a and b to the detection circuit 19, respectively.

When a load is applied to the transmission shaft 14, the transmission shaft 14 is twisted, so that the first and second detection signals a and b detected by the first and second detectors Ca and Cb are as shown in FIG. Then, the phase shifts. The detection circuit 19 detects a lap time S in which the detection times Sa and Sb of the first and second detectors Ca and Cb wrap, and the lap signal c of the lap time S is detected.
Is output to the comparison circuit 21 of FIG.

A first set value S1 or a second set value S2 is input to the comparison circuit 21 from a setter 22 having a selector. The comparison circuit 21 compares the lap time S with the first set value S1, and when the lap time S is smaller than the first set value S1,
That is, the closing signal Sh for closing the valve 9C is output during the pumping operation, and at the same time, the display 33 indicates that "pumping". On the other hand, the comparison circuit 21 compares the lap time S with the second set value S2, and if the lap time S is larger than the second set value S2, that is, the valve 9C is opened during air operation. The valve signal Op is output, and at the same time, the display 33 indicates that "standby". The first set value S1 is smaller than the second set value S2.

The detection circuit 19, the comparison circuit 21, and the setting device 22 are incorporated in one control device 20.

In addition, in this vertical pump 1, the minimum water level LWL peculiar to the pump that sucks air when the depth of the water intake port is less than this
The impeller 3 is disposed above the
An intake pipe 13 is provided below the inlet of the valve, that is, in the impeller chamber, and an intake pipe 13 having an air / water switching intake valve 12 is provided in the middle thereof. Therefore, when the water level falls, when the water level reaches a predetermined level between the pumping start water level HWL at the impeller inlet level and the pump's lowest water level (pumping cutoff water level) LWL, the intake valve 12 is opened to the inlet of the impeller 3. When pumping air to switch from pumping operation to aerial operation, and when the water level rises, when the water level in the suction well 6 reaches the inlet level HWL of the impeller 3, the intake valve 12 is closed and the remaining air is sucked up. It is designed to switch from medium operation to pumping operation.

The intake valve 12 is opened and closed based on a signal output to the intake valve 12 from the pumping start water level HWL or LWL detected by a water level gauge (not shown).

Next, a method of detecting the operating condition of the vertical shaft pump 1 and a method of supplying lubricating water to the bearings 5 and 8 will be described.

In the operating state of the vertical shaft pump 1 in which the main shaft 2 is rotationally driven, if the water level of the suction well 6 is equal to or higher than the pumping start water level HWL, the intake valve 12 of the intake pipe 13 is closed, and the impeller 3
The pumping operation is performed because the water is sucked up.
In this case, since the shaft power of the main shaft 2 is larger than that during air operation, the twist of the transmission shaft 14 becomes large, and the two detected parts 1
The relative displacement of 5,17 becomes large. Therefore, the second
The wrap time S of the two detection signals a and b shown in the figure becomes shorter. The lap time S is detected by the detection circuit 19 of FIG. 1 and is displayed on the display 33 via the comparison circuit 21, so that it can be known that the vertical pump 1 is in the pumping operation.

Further, since the shaft power and the discharge amount of the main shaft 2 have a constant relationship depending on the type of pump and the installation conditions, the characteristics of the pump are checked in advance and input to the comparison circuit 21, so that the detection circuit 19 outputs The operating state of the pump can be known by converting the detection signal c into the axial power and the discharge amount on the display 33 via the comparison circuit 21 and displaying them digitally.

On the other hand, a comparison circuit that receives the detection signal c from the detection circuit 19
21 is the lap time S and the first set value S1 from the setter 22.
When the lap time S is smaller than the first set value S1, that is, during the pumping operation in which the shaft power is larger than a predetermined value, the closing signal Sh is output to the valve 9C and the valve 9C is closed. It In this case, the bearings 5 and 8 are lubricated and cooled by the self-lifted water sucked up by the impeller 3.

By continuing the pumping operation, even if the water level falls below the pumping start water level HWL, the closed state of the intake valve 12 is maintained until the pumping cutoff water level LWL falls, and the bearing 5 by self-pumping, 8 Lubrication and cooling continue.

When the water level drops near the pumping cutoff water level LWL, the intake valve 12
Is closed and air is sent to the inlet of the impeller 3 to switch from pumping operation to air operation. During this air operation, the torques of the main shaft 2 and the transmission shaft 14 are significantly reduced,
First and second detection signals output from both detectors Ca and Cb
The phases of a and b become smaller, and the lap time S in FIG. 2 becomes longer.

Here, the comparison circuit 21 of FIG. 1 has the lap time S of the wrap signal c from the detection circuit 19 and the second set value from the setter 22.
By comparing with S2, when the lap time is longer than the second set value S2, the valve opening signal Op is output to the valve 9C. This allows
When the valve 9C is opened, the lubricating water supply system 9 moves to the bearing of the pump main shaft 2.
Lubricating water is supplied to the bearings 5, 8 to lubricate and cool the bearings 5, 8 so that stable operation can be continued.

When the water level of the water intake well 6 rises to reach the pumping start water level HWL due to the continuation of the air operation, the pumping operation is switched to the pumping operation as described above, and the bearings 5 and 8 are lubricated by the self-pumping.

As described above, since the bearings 5 and 8 are lubricated and cooled by the lubricating water supplied from the lubricating water supply source 9 during the air operation of the vertical shaft pump 1, the preceding standby operation in which the dry operation is continued for a long time is performed. The ceramic bearings 5 and 8 can also be used for the vertical pump 1 that performs the air management operation.

Needless to say, the present invention can be applied not only to the vertical shaft pump 1 described in the above embodiment, but also to other pumps that can perform air operation.

Further, in the above embodiment, the first and second discs 16, 18 are
Although the first and second detected portions 15 and 17 formed of slits are provided in the above, both detected portions 15 and 17 may be formed of a reflecting plate or may be directly provided to the transmission shaft 14.

Further, in the above-mentioned embodiment, both detectors Ca and Cb are reflection type optical sensors, but both detectors Ca and Cb may be transmission type optical sensors.

Further, in the above embodiment, the operating condition is detected and the lubricating water is supplied based on the lap time S of both detection signals a and b in FIG. 2, but it is based on the phase φ of both detection signals a and b. You may go.

Further, in the above embodiment, the lap time S is set to the first value in FIG.
Although the comparison is made with the set value S1 and the second set value S2, S1 = S2 may be set. Further, the configuration of the control device 20 is not limited to that of the above embodiment.

〔The invention's effect〕

As described above, according to the present invention, during the pumping operation in which the axial power of the pump is large due to the high load operation, and in the air operation in which the axial power of the pump is small in the low load operation, the prime mover Paying attention to the fact that the twist generated in the transmission shaft that transmits the output to the pump fluctuates, the first and second optical detection means provided separately in the axial direction of the transmission shaft in order to effectively utilize this point. By detecting by comparing the lap time or phase, which is the detection signal by each, with a predetermined value set in advance, it is possible to eliminate the need for a shaft rotation speed detection device and a high-frequency pulse light source, which are necessary for torque measurement. It is possible to accurately detect whether the pumping operation or the air operation is performed regardless of the condition of the water surface of the suction well while keeping the cost down, and the pump has a certain relationship with the axial power of the pump. The discharge amount even to accurately detect an effect that it is possible to accurately grasp the operating conditions of the pump as a whole.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a vertical shaft pump to which the present invention is applied, and FIG. 2 is a characteristic diagram showing a relationship between first and second detection signals and a lap signal. 1 ... Pump (vertical shaft pump), 2 ... Main shaft, 5,8 ... Bearing, 9 ... Lubricating water supply system, 10 ... Motor, 14 ... Transmission shaft, 15 ... First detected part, 17 ...... Second detected part, Ca ......
1st detector, Cb ... 2nd detector, a ... 1st detection signal,
b ... Second detection signal.

Continuation of front page (56) References JP 62-237096 (JP, A) JP 61-207940 (JP, A)

Claims (1)

(57) [Claims] 1. A transmission shaft for transmitting the output of a prime mover to a pump is provided with first and second discs having first and second detected portions which are slits and are separated from each other in the axial direction thereof. An optical first and second optical type that outputs the first and second detection signals by irradiating the first and second discs with light to detect the time of light transmission to the first and second detected portions, respectively. Whether the pumping operation or the air operation is performed by providing a detector and comparing the lap time or phase of the first and second detection signals by the first and second detectors with a preset predetermined value. Is detected and the discharge amount of the pump is also detected.