JP2014218988A - Pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump device that can improve performance in a broad operation range from an operation region of low-pressure and large flow rate to an operation region of high-pressure and small flow rate while suppressing rating output of a motor used for driving a pump.SOLUTION: In the pump device, when a load on the motor 20 for driving a pump unit 10 is increased, the revolving speed of the motor is reduced, and when the load on that is reduced, the revolving speed of the motor is increased and the revolving speed of the motor 20 is controlled so that the load does not exceed a predetermined upper limit. Thus, compared with a conventional method that maintains the revolving speed of a motor constant, the pump device can be improved in the performance thereof in a broad operation range from an operation region of low-pressure and large flow rate to an operation region of high-pressure and small flow rate.

Description

  The present invention relates to a pump device provided with a prime mover for driving, and more particularly to a pump device having improved performance in an operation region where discharge pressure is high and flow rate is low.

  In general, a centrifugal centrifugal pump is a load (power required to drive a rotating shaft) in an operating region where the pressure is high and the amount of water is low (when the distance to the drainage site, the head is long, or when the discharge port is throttled). In contrast, it is known that the load is large in an operation region where the pressure is low and the amount of water is large (see the following patent document).

JP 2000-227084 A

  The prime mover used to drive the pump must be selected to meet the maximum power required for operation. In the case of the centrifugal centrifugal pump, since it has the above characteristics, the prime mover is selected in accordance with the maximum load at a low pressure and a large flow rate. However, even if a prime mover with large power is selected for low pressure and large flow rate, the power becomes excessive at high pressure and small flow rate. That is, although a prime mover with high power is selected, the power does not contribute to the performance of the pump in the high pressure / low flow operation region, and is wasted.

  The present invention has been made in view of such circumstances, and its purpose is wide from a low pressure / high flow rate operation region to a high pressure / low flow rate operation region while suppressing the rated output of the prime mover used to drive the pump. An object of the present invention is to provide a pump device capable of improving performance in the operating range.

  The pump device according to the present invention includes a pump unit, a prime mover that drives the pump unit, a rotational speed detection unit that detects a rotational speed of the prime mover, and the rotational speed detected by the rotational speed detection unit is a target rotation. A rotation speed control unit that controls the rotation speed of the prime mover so as to approach the speed, a load detection unit that detects a load of the prime mover, and the rotation speed becomes slow when the load increases, and the load decreases The target according to the detected value of the load in the load detection unit so as to approach a predetermined relationship between the load and the rotational speed at which the rotational speed is increased and an upper limit value of the load is determined. And a target rotation speed adjustment unit that adjusts the rotation speed.

  Preferably, the pump unit is a self-priming pump, and the target rotation speed adjustment unit receives the signal for instructing the pump unit to start, and is the fastest rotation speed defined in the predetermined relationship. A faster target rotational speed for self-priming operation is set in the rotational speed control section.

  Preferably, the target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then compares the detected value of the load with a predetermined lower limit value to detect the load. If the value exceeds the lower limit value, the adjustment of the target rotational speed according to the detected value of the load is performed.

  Preferably, the target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then the state where the detected value of the load is smaller than the lower limit value continues for a certain period of time. The rotation of the prime mover is stopped.

  Preferably, when the target rotational speed adjustment unit receives a signal instructing start of the pump unit, the target rotational speed adjustment unit sets a predetermined initial target rotational speed in the rotational speed control unit, and detects the load after the setting. If the detected value of the load is smaller than the lower limit value, the target rotational speed for the self-priming operation is set in the rotational speed control unit.

  Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the predetermined rotational speed corresponding to the detected value of the load in the predetermined relationship; A difference from the target rotational speed being set in the rotational speed control unit is calculated, and if the calculated difference exceeds a predetermined threshold value, a range from the predetermined rotational speed to the target rotational speed being set is set. A new target rotational speed that is included and has a difference from the predetermined rotational speed smaller than the calculated difference is set in the rotational speed control unit.

  Preferably, the target rotation speed adjustment unit sets an intermediate rotation speed in a range from the predetermined rotation speed to the target rotation speed being set in the rotation speed control unit as the new target rotation speed.

  Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, if the detected value of the load exceeds the upper limit value, the detected value of the load is The target rotational speed is decreased until it becomes smaller than the upper limit value.

  Preferably, the target rotational speed adjustment unit has a minimum rotational speed at which the detected value of the load exceeds the upper limit value and the target rotational speed set in the rotational speed control unit is defined in the predetermined relationship. If it is faster, the lowest rotational speed is set as the target rotational speed in the rotational speed control unit, and even after the setting, if the detected value of the load exceeds the upper limit value, the detected value of the load is The target rotational speed is decelerated by a predetermined change amount until it becomes smaller than the upper limit value.

  Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the target rotational speed set in the rotational speed control unit is defined in the predetermined relationship. If the detected value of the load is smaller than the upper limit value and the difference between the detected value of the load and the upper limit value exceeds a predetermined threshold value, the detected value of the load And the target rotation speed is increased until the difference between the upper limit value and the upper limit value becomes smaller than the threshold value.

  According to the present invention, when the load increases, the rotational speed decreases, and when the load decreases, the rotational speed increases, and the rotational speed is controlled so that the load does not exceed a predetermined upper limit. Performance can be improved over a wide operating range from low pressure / high flow rate operation range to high pressure / low flow rate operation range.

It is a figure which shows an example of the external appearance of the pump apparatus which concerns on embodiment of this invention. It is a figure which illustrates the internal structure of the pump part in the pump apparatus shown in FIG. It is a figure which shows an example of a structure of the control system in the pump apparatus which concerns on embodiment of this invention. It is a graph showing the relationship between the throttle opening and the rotation speed. It is a flowchart for demonstrating the adjustment operation of the rotational speed from the start of a pump to a stop. It is a flowchart for demonstrating the operation | movement in connection with adjustment of a target rotational speed. It is a figure for demonstrating the example which adjusts a target rotational speed so that the relationship between a predetermined load and rotational speed may be approached. It is a flowchart for demonstrating operation | movement when load exceeds an upper limit. 5 is a flowchart for explaining an operation when a load is smaller than an upper limit value and a target rotation speed is slower than a minimum rotation speed in FIG. 4. 4 is a graph showing the relationship between the discharge flow rate Q and the head H, and the relationship between the discharge flow rate Q and the throttle opening S. It is a flowchart for demonstrating adjustment operation | movement of rotational speed in the pump apparatus which concerns on other embodiment of this invention.

  Drawing 1 is a figure showing an example of the appearance of the pump device concerning the embodiment of the present invention. The pump device shown in FIG. 1 has a pump unit 10 and a prime mover 20. The pump unit 10 and the prime mover 20 are fixed in the frame 5.

  A prime mover 20 shown in FIG. 1 is an engine as an internal combustion engine. The prime mover 20 (engine) includes a device (such as an electronic governor) that adjusts the opening degree (throttle opening degree) of a throttle valve disposed in the intake passage so that a target rotational speed can be obtained.

  The pump unit 10 shown in FIG. 1 is a spiral centrifugal pump. FIG. 2 shows an example of the internal configuration of the pump unit 10. The pump unit 10 includes an impeller 14 coupled to a rotating shaft 21 of a prime mover 20 and a spiral casing 13 that houses the impeller 14. When the impeller 14 rotates, the water (fluid) in the suction port 11 is conveyed to the discharge port 12 through the spiral casing 13.

  The pump unit 10 is, for example, a self-priming pump, and can start the pump operation even when air is accumulated in the suction-side piping by being started with priming water inside. The filling tap 15 is used to fill the inside of the pump unit 10 with priming water at the time of starting.

FIG. 3 is a diagram illustrating a configuration example of a control system of the pump device according to the embodiment of the present invention.
In the example of FIG. 3, the pump device includes a rotation speed detection unit 30 that detects the rotation speed of the prime mover 20, a load detection unit 40 that detects a load of the prime mover 20 (power necessary for driving the rotary shaft 21), and a control. Part 50.

  For example, the rotation speed detection unit 30 converts a magnetic flux change of a magnet that rotates in conjunction with a gear inside the prime mover 20 into a pulse signal by a Hall sensor, and detects the rotation speed based on the frequency of the pulse signal.

  The load detection unit 40 is, for example, a sensor that detects the opening (throttle opening) of a throttle valve disposed in the intake passage of the prime mover 20 as a signal related to the load of the prime mover 20. This sensor includes, for example, a potentiometer.

  The control unit 50 is a device that controls the operation of the prime mover 20 and includes, for example, a microcomputer. The control unit 50 drives an actuator that adjusts the throttle valve and choke valve of the prime mover 20 in accordance with signals from the rotation speed detection unit 30 and the load detection unit 40 to obtain an appropriate rotation speed according to the load state. To control.

The control unit 50 includes a rotation speed control unit 51 and a target rotation speed adjustment unit 52 as functional components related to rotation speed control.
The rotation speed control unit 51 controls the rotation speed of the prime mover 20 so that the rotation speed detected by the rotation speed detection unit 30 approaches the target rotation speed Rt.
The target rotation speed adjustment unit 52 sets the load detection value (throttle opening S) in the load detection unit 40 so that the relationship between the load and the rotation speed of the prime mover 20 approaches a predetermined relationship (FIG. 4). Accordingly, the target rotational speed Rt is adjusted.

FIG. 4 is a graph showing the relationship between the throttle opening S and the rotation speed Ra. The rotational speed Ra in FIG. 4 indicates the rotational speed of the prime mover 20 determined with respect to the throttle opening S detected by the load detection unit 40. In the example of FIG. 4, the rotational speed Ra is determined so as to decrease substantially in proportion to the throttle opening S. The throttle opening S has, for example, a numerical range from “0” to “95”, where “0” indicates the fully closed state of the throttle valve and “95” indicates the fully open state.
The target rotation speed adjustment unit 52 may calculate the value of the rotation speed Ra corresponding to the throttle opening S based on, for example, a predetermined calculation formula, or correspond the throttle opening S and the rotation speed Ra. Then, it may be read from the data table stored in the storage device.

  The target rotation speed adjustment unit 52 adjusts the target rotation speed Rt so as to approach the relationship between the throttle opening S and the rotation speed Ra shown in FIG. In other words, the target rotational speed adjustment unit 52 adjusts the target rotational speed Rt so that the rotational speed decreases when the load of the prime mover 20 increases, and the rotational speed increases when the load decreases. Further, the target rotational speed adjustment unit 52 adjusts the target rotational speed Rt so that the load of the prime mover 20 does not exceed a predetermined upper limit value (throttle opening S = 80).

  Further, when a signal from a switch (not shown) for instructing the start of the pump unit 10 is input to the control unit 50, the target rotation speed adjustment unit 52 is related to the throttle opening S and the rotation speed Ra shown in FIG. The target rotational speed Rt (for example, 4000 rpm) for self-priming operation, which is faster than the fastest rotational speed (3800 rpm) in the above, is set in the rotational speed controller 51 (self-priming operation mode).

  After setting a high target rotation speed Rt for self-priming operation in the rotation speed control unit 51, the target rotation speed adjustment unit 52 compares the throttle opening S detected by the load detection unit 40 with a predetermined lower limit value. . When the throttle opening S exceeds this lower limit value, the target rotation speed adjustment unit 52 rotates from the self-priming operation mode in which a high target rotation speed Rt for self-priming operation is set to the throttle opening S and rotation shown in FIG. The operation mode (normal operation mode) for adjusting the target rotation speed Rt so as to approach the relationship with the speed Ra is shifted to.

  However, if the throttle opening S is smaller than a predetermined lower limit value even after a fixed time has elapsed since the target rotational speed Rt for self-priming operation is set in the rotational speed control section 51, the target rotational speed adjustment section 52 The rotation of the prime mover 20 is stopped. This prevents the self-priming mode from continuing for a long period of time and causing an excessive burden on the prime mover 20 and the pump unit 10 due to the high rotational speed state.

  When shifting from the self-priming operation mode to the normal operation mode, the target rotation speed adjustment unit 52 corresponds to the throttle opening S detected by the load detection unit 40 in the relationship between the throttle opening S and the rotation speed Ra shown in FIG. The predetermined rotational speed Ra is acquired, and a difference DR between the target rotational speed Rt currently set in the rotational speed control unit 51 and the rotational speed Ra is calculated. The target rotational speed adjustment unit 52 compares the difference DR with a predetermined threshold value, and if the difference DR exceeds the threshold value (the target rotational speed Rt is away from the rotational speed Ra), the target currently being set A new target rotation speed Rt closer to the rotation speed Ra than the rotation speed Rt is set in the rotation speed control unit 51. That is, the target rotational speed adjustment unit 52 is a new target rotational speed that is included in the range from the rotational speed Ra to the current target rotational speed Rt and that has a difference from the rotational speed Ra that is smaller than the current target rotational speed Rt. Rt is set in the rotation speed control unit 51. For example, the target rotational speed adjustment unit 52 sets an intermediate rotational speed in the range from the rotational speed Ra to the current target rotational speed Rt as the new target rotational speed Rt in the rotational speed control unit 51 (FIG. 7).

  When the throttle opening S of the load detection unit 40 exceeds the upper limit value (80) in the normal operation mode, the target rotational speed adjustment unit 52 causes the throttle opening S of the load detection unit 40 to be smaller than the upper limit value (80). Until the target rotational speed Rt is decreased. For example, the target rotational speed adjustment unit 52 performs a process of decelerating the target rotational speed Rt by a predetermined change amount according to a comparison result between the throttle opening S and the upper limit value (80). ) Repeat until smaller. The target rotational speed Rt may be reduced by, for example, subtracting a constant speed from the original speed, or by reducing the overall speed by a constant rate.

  Next, the rotation speed adjustment operation in the pump apparatus having the above-described configuration will be described with reference to a flowchart.

FIG. 5 is a flowchart for explaining the operation of adjusting the rotational speed from the start to the stop of the pump.
When a signal from a switch or the like (not shown) for instructing start of the pump unit 10 is input to the control unit 50 (ST105), the target rotation speed adjustment unit 52 sets the high target rotation speed Rt for self-priming operation to the rotation speed. The control unit 51 is set (ST125). Accordingly, the pump device starts operation at a high rotational speed for self-priming operation (self-priming operation mode).
On the other hand, when the pump is not started (for example, in the case of restarting or the like), the target rotation speed adjustment unit 52 proceeds to step ST140 described later.

  When the rotational speed of the prime mover 20 reaches the target rotational speed Rt for self-priming operation by the control of the rotational speed control section 51, the target rotational speed adjustment section 52 acquires the throttle opening S from the load detection section 40 (ST130). This is compared with a predetermined lower limit value (ST135). In the self-priming operation, the load on the prime mover 20 is significantly reduced, so that the throttle opening S is lower than the lower limit value.

  When the throttle opening S is smaller than the lower limit (when the self-priming operation continues), the target rotational speed adjustment unit 52 sets the target rotational speed Rt for the self-priming operation in the rotational speed control unit 51. It is determined whether or not the elapsed time has reached a certain time (ST180). When the elapsed time (time in the self-priming operation mode) is shorter than the predetermined time, the target rotational speed adjustment unit 52 returns to step ST130 and repeats the determination of whether or not the throttle opening S exceeds the lower limit value. When the elapsed time reaches a certain time, the target rotational speed adjustment unit 52 proceeds to step ST155 and stops the rotation of the prime mover 20. As a result, it is possible to prevent a high rotation speed in the self-priming operation mode from continuing for a long time and applying an excessive burden to the prime mover 20 and the pump unit 10.

  When the throttle opening S becomes larger than a predetermined lower limit value (when the self-priming operation ends and the pumping of water starts), the target rotational speed adjustment unit 52 shifts to the normal operation mode. The target rotation speed adjustment unit 52 sets the target rotation speed Rt to a predetermined initial value (eg, 3600 rpm) (ST140), and starts adjusting the target rotation speed according to the throttle opening S of the load detection unit 40 (ST145). ). In a normal operation mode, when a signal from a switch (not shown) that instructs to stop the pump is input to the control unit 50 (ST150), the target rotation speed adjustment unit 52 stops the rotation of the prime mover 20.

FIG. 6 is a flowchart showing details of the process in step ST145 of FIG. 5, and shows operations related to the adjustment of the target rotational speed Rt in the normal operation mode.
The target rotational speed adjustment unit 52 acquires the throttle opening S from the load detection unit 40 (ST205), and determines whether the throttle opening S is larger than the upper limit value (80) (ST210). When the throttle opening S is larger than the upper limit (80), the target rotational speed adjustment unit 52 proceeds to step ST305 (FIG. 8) described later. Further, it is determined whether or not the target rotational speed Rt currently set in the rotational speed control unit 51 is slower than the lowest rotational speed (3600 rpm) in the graph shown in FIG. The process proceeds to step ST405 (FIG. 9).

  When the throttle opening S is smaller than the upper limit value (80) and the target rotational speed Rt is faster than the lowest rotational speed (3600 rpm) in the graph shown in FIG. 4, the target rotational speed adjustment unit 52 is acquired in step ST205. A predetermined rotational speed Ra (FIG. 4) corresponding to the throttle opening S is acquired (ST220), and a difference DR between the target rotational speed Rt and the rotational speed Ra is calculated (ST225). When the difference DR is larger than the threshold value, the target rotational speed adjustment unit 52 sets the intermediate value between the target rotational speed Rt and the rotational speed Ra as a new target rotational speed Rt in the rotational speed control unit 51 (ST235). . When the difference DR is smaller than the threshold value, the target rotation speed adjustment unit 52 maintains the target rotation speed Rt being set.

  FIG. 7 is a diagram for explaining an example of adjusting the target rotational speed Rt so as to approach the relationship between the load (throttle opening S) and the rotational speed shown in the graph of FIG. The graph shown in FIG. 7 represents a part of the graph shown in FIG. “P1” to “P3” in FIG. 7 indicate operating points of the prime mover 20 represented by the throttle opening S and the target rotational speed Rt.

  The rotational speed Ra1 determined corresponding to the throttle opening S1 at the operating point P1 is faster than the target rotational speed Rt1 at the operating point P1, and the difference DR is larger than the threshold value. Therefore, an intermediate value Rt2 between the rotational speed Ra1 and the target rotational speed Rt1 is set as a new target rotational speed (ST235).

  Since the new target rotational speed Rt2 is faster than the original target rotational speed Rt1, the load on the prime mover 20 increases. Therefore, by changing the target rotational speed from “Rt1” to “Rt2”, the throttle opening becomes “S2” which is larger than the original “S1”. That is, the new operating point P2 (S2, Rt2) moves in the upper right direction of the original operating point P1 (S1, Rt1). As shown in FIG. 7, the operation P2 is closer to a graph line representing the relationship between the load (throttle opening S) and the rotation speed than the original operation point P1.

  In the example of FIG. 7, the operating point moves from “P2” to “P3” by further adjusting the target rotational speed Rt. Similarly to the above, the target rotational speed Rt3 at the operating point P3 is obtained as an intermediate value between the rotational speed Ra2 corresponding to the throttle opening S2 at the operating point P2 and the target rotational speed Rt2. The operating point P3 is closer to the line on the graph than the operating point P2.

  As described above, by repeating the processes of steps ST205 to ST235, the rotational speed of the prime mover 20 approaches the relationship between the load and the rotational speed shown in the graph of FIG. 4 until the difference DR becomes smaller than a predetermined threshold value. To be controlled.

FIG. 8 is a flowchart for explaining the operation when the load (throttle opening S) detected by the load detector 40 exceeds the upper limit value (80).
When it is determined in step ST210 (FIG. 6) that the throttle opening S is larger than the upper limit value (80), the target rotational speed adjustment unit 52 sets the target rotational speed Rt set in the rotational speed control unit 51 to 3600 rpm (FIG. 6). 4 is determined whether it is faster than the minimum rotational speed in the graph shown in FIG. 4 (ST305). When the target rotation speed Rt is slower than 3600 rpm, the target rotation speed adjustment unit 52 sets a new target rotation speed Rt obtained by decelerating the target rotation speed Rt by a predetermined change in the rotation speed control unit 51 (ST325).

  On the other hand, when target rotation speed Rt is faster than 3600 rpm, target rotation speed adjustment unit 52 sets target rotation speed Rt to 3600 rpm (ST310). When the rotational speed of the prime mover 20 reaches 3600 rpm, the target rotational speed adjustment unit 52 acquires the throttle opening S of the load detection unit 40 again (ST315) and compares it with the upper limit value (80) (ST320). If the throttle opening S exceeds the upper limit (80) even if the rotation speed is set to 3600 rpm, the target rotation speed adjustment unit 52 reduces the target rotation speed Rt by a predetermined change amount to a new target rotation speed Rt. Is set in the rotation speed control unit 51 (ST325).

By repeating the processes of steps ST305 to ST325 described above, the target rotational speed Rt of the prime mover 20 is decelerated until the throttle opening S becomes smaller than the upper limit value (80).
In the process shown in the flowchart of FIG. 8, when the load (throttle opening S) exceeds the upper limit (80) at a rotational speed faster than the lowest rotational speed (3600 rpm) in the graph shown in FIG. Rt is immediately decelerated to the lowest rotational speed (3600 rpm). Thereby, the time which an excessive load is applied to the prime mover 20 can be shortened.

9 shows a case where the load (throttle opening S) detected by the load detector 40 is smaller than the upper limit value (80) and the target rotational speed Rt is slower than the lowest rotational speed (3600 rpm) in FIG. It is a flowchart for demonstrating operation | movement.
In this case, the target rotational speed adjustment unit 52 calculates a difference DS between the throttle opening S detected by the load detection unit 40 and the upper limit value (80) (ST405), and this difference DS is calculated from a predetermined threshold value. It is determined whether it is larger (ST410). When the difference DS is larger than a predetermined threshold value, the target rotational speed adjustment unit 52 sets a new target rotational speed Rt obtained by increasing the target rotational speed Rt by a predetermined change in the rotational speed control unit 51 ( ST415). The target rotational speed Rt may be increased by, for example, adding a constant speed to the original speed, or by increasing the overall speed by a constant rate.

  By repeating the processes of steps ST405 to ST415 described above, the target rotational speed Rt of the prime mover 20 is increased until the difference DS between the throttle opening S and the upper limit value (80) becomes smaller than a predetermined threshold value. .

FIG. 10 is a graph showing an example of the performance of the pump device. Curves CV1 and CV2 represent the relationship between the discharge flow rate Q and the head H, and the curve CV3 represents the relationship between the discharge flow rate Q and the throttle opening S.
A curved line CV1 indicated by a dotted line represents characteristics when the rotational speed of the prime mover is maintained at a rated speed (3600 rpm), and a curved line CV2 indicated by a solid line shows the relationship between the load (throttle opening S) and the target rotational speed Rt. The characteristic at the time of performing the control mentioned above so that the relationship shown in 4 may be approximated is represented.
As can be seen by comparing the curves CV1 and CV2, the head H at the same discharge water amount Q is increased by controlling the target rotational speed Rt. Further, the load (throttle opening S) is restricted so as not to exceed the upper limit (80) in the operation region where the discharged water amount Q is larger than 300 [liter / min].

  As described above, according to the pump device according to the present embodiment, when the load of the prime mover 20 that drives the pump unit 10 is increased, the rotation speed is decreased, and when the load is decreased, the rotation speed is increased. The rotational speed of the prime mover 20 is controlled so that does not exceed a predetermined upper limit. Therefore, as shown in the graph of FIG. 10, the performance is improved over a wide operating range from the low pressure / large flow rate operation range to the high pressure / small flow rate operation range, compared to the conventional method of keeping the rotation speed of the prime mover constant. it can.

  Further, according to the pump device according to the present embodiment, in the self-priming operation mode at the time of starting the pump, since the rotational speed of the prime mover 20 is made higher than that in the normal operation mode, the substantial pump operation is started. Time can be shortened. Further, whether or not the self-priming operation has ended is determined based on the load of the prime mover 20 (throttle opening S), and when the end of the self-priming operation is determined, the mode automatically shifts to the normal operation mode. The pump operation can be started. Moreover, since the rotation of the prime mover 20 is stopped when the self-priming operation mode continues for a certain time, the excessive load on the prime mover 20 and the pump unit 10 due to the high rotational speed for the self-priming operation continues for a long time. It can be effectively prevented.

  In addition, this invention is not limited to embodiment mentioned above, Various modifications are included.

FIG. 11 is a flowchart for explaining a rotation speed adjusting operation in a pump device according to another embodiment of the present invention.
The flowchart shown in FIG. 11 is obtained by adding steps ST110 to ST120 between step ST105 and step ST125 in the flowchart shown in FIG.
In this case, the target rotational speed adjusting unit 52 receives an input of the pump start signal and sets the target rotational speed Rt to a high rotational speed (for example, 4000 rpm) for self-priming operation, so that the rotational speed slower than this is set. (For example, 3600 rpm) is set in the rotational speed control unit 51 as the initial target rotational speed Rt (ST110). Then, the target rotational speed adjustment unit 52 acquires the throttle opening S of the load detection unit 40 at this initial rotational speed (ST115), and determines whether the throttle opening S is smaller than a predetermined lower limit value (ST115). ST120). When the throttle opening S is smaller than the lower limit value, the target rotational speed adjustment unit 52 sets the target rotational speed Rt to a high rotational speed for self-priming operation (ST125).
As described above, according to the processing of the flowchart of FIG. 11, since the self-priming operation is confirmed at a relatively low rotational speed and then the rotational speed is changed to a high rotational speed, an excessive load is applied to the prime mover 20 and the pump unit 10. Can be effectively prevented.

  In the embodiment described above, the difference DR between the rotation speed Ra (FIG. 4) corresponding to the load detection value and the target rotation speed Rt in the normal operation mode in which the load detection value (throttle opening) is smaller than the upper limit value (80). Is larger than a predetermined threshold value, the rotational speed intermediate between the rotational speed Ra and the target rotational speed Rt is set as a new target rotational speed Rt (ST235, FIG. 6), but the present invention is limited to this. Not. That is, the new target rotational speed Rt is included in the range from the rotational speed Ra corresponding to the load detection value to the original target rotational speed Rt, and the difference DR from the rotational speed Ra is the original target rotational speed Rt. The rotation speed may be any lower speed than that of the rotation speed, and is not limited to an intermediate value between the rotation speed Ra and the target rotation speed Rt as described above.

  In embodiment mentioned above, although the case where the pump part 10 is a centrifugal pump is mentioned as an example, this invention is not limited to this. Various types of pumps other than centrifugal pumps may be used in the pump unit of the present invention.

  In the embodiment described above, a case where the prime mover 20 is an engine (reciprocating engine) is taken as an example, but the present invention is not limited to this. Various types of internal combustion engines may be used for the prime mover of the present invention. For example, an electric motor may be used as a power source other than the internal combustion engine.

DESCRIPTION OF SYMBOLS 5 ... Frame, 10 ... Pump part, 11 ... Suction port, 12 ... Discharge port, 13 ... Spiral casing, 14 ... Impeller, 15 ... Water filling stopper, 20 ... Motor | power_engine, 21 ... Rotating shaft, 30 ... Rotation speed detection part, DESCRIPTION OF SYMBOLS 40 ... Load detection part, 50 ... Control part, 51 ... Rotational speed control part, 52 ... Target rotational speed adjustment part.

  The present invention relates to a pump device provided with a prime mover for driving, and more particularly to a pump device having improved performance in an operation region where discharge pressure is high and flow rate is low.

  In general, a centrifugal centrifugal pump is a load (power required to drive a rotating shaft) in an operating region where the pressure is high and the amount of water is low (when the distance to the drainage site, the head is long, or when the discharge port is throttled). In contrast, it is known that the load is large in an operation region where the pressure is low and the amount of water is large (see the following patent document).

JP 2000-227084 A

  The prime mover used to drive the pump must be selected to meet the maximum power required for operation. In the case of the centrifugal centrifugal pump, since it has the above characteristics, the prime mover is selected in accordance with the maximum load at a low pressure and a large flow rate. However, even if a prime mover with large power is selected for low pressure and large flow rate, the power becomes excessive at high pressure and small flow rate. That is, although a prime mover with high power is selected, the power does not contribute to the performance of the pump in the high pressure / low flow operation region, and is wasted.

  The present invention has been made in view of such circumstances, and its purpose is wide from a low pressure / high flow rate operation region to a high pressure / low flow rate operation region while suppressing the rated output of the prime mover used to drive the pump. An object of the present invention is to provide a pump device capable of improving performance in the operating range.

A pump device according to a first aspect of the present invention includes a pump unit, a prime mover that drives the pump unit, a rotational speed detection unit that detects a rotational speed of the prime mover, and the rotational speed detection unit that detects the rotational speed. A rotation speed control unit that controls the rotation speed of the prime mover, a load detection unit that detects a load of the prime mover, and the rotation speed decreases as the load increases, so that the rotation speed approaches a target rotation speed, The detected value of the load in the load detecting unit approaches the predetermined relationship between the load and the rotational speed, in which the rotational speed increases as the load decreases and the upper limit value of the load is determined. And a target rotational speed adjusting unit that adjusts the target rotational speed according to the above.

  Preferably, the pump unit is a self-priming pump, and the target rotation speed adjustment unit receives the signal for instructing the pump unit to start, and is the fastest rotation speed defined in the predetermined relationship. A faster target rotational speed for self-priming operation is set in the rotational speed control section.

  Preferably, the target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then compares the detected value of the load with a predetermined lower limit value to detect the load. If the value exceeds the lower limit value, the adjustment of the target rotational speed according to the detected value of the load is performed.

  Preferably, the target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then the state where the detected value of the load is smaller than the lower limit value continues for a certain period of time. The rotation of the prime mover is stopped.

Preferably, when the target rotational speed adjustment unit receives a signal instructing start of the pump unit, the target rotational speed adjustment unit sets an initial target rotational speed slower than the target rotational speed for the self-priming operation in the rotational speed control unit. After the setting, the load detection value is compared with the lower limit value, and if the load detection value is smaller than the lower limit value, the target rotation speed for the self-priming operation is transferred to the rotation speed control unit. Set.

  Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the predetermined rotational speed corresponding to the detected value of the load in the predetermined relationship; A difference from the target rotational speed being set in the rotational speed control unit is calculated, and if the calculated difference exceeds a predetermined threshold value, a range from the predetermined rotational speed to the target rotational speed being set is set. A new target rotational speed that is included and has a difference from the predetermined rotational speed smaller than the calculated difference is set in the rotational speed control unit.

  Preferably, the target rotation speed adjustment unit sets an intermediate rotation speed in a range from the predetermined rotation speed to the target rotation speed being set in the rotation speed control unit as the new target rotation speed.

  Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, if the detected value of the load exceeds the upper limit value, the detected value of the load is The target rotational speed is decreased until it becomes smaller than the upper limit value.

  Preferably, the target rotational speed adjustment unit has a minimum rotational speed at which the detected value of the load exceeds the upper limit value and the target rotational speed set in the rotational speed control unit is defined in the predetermined relationship. If it is faster, the lowest rotational speed is set as the target rotational speed in the rotational speed control unit, and even after the setting, if the detected value of the load exceeds the upper limit value, the detected value of the load is The target rotational speed is decelerated by a predetermined change amount until it becomes smaller than the upper limit value.

  Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the target rotational speed set in the rotational speed control unit is defined in the predetermined relationship. If the detected value of the load is smaller than the upper limit value and the difference between the detected value of the load and the upper limit value exceeds a predetermined threshold value, the detected value of the load And the target rotation speed is increased until the difference between the upper limit value and the upper limit value becomes smaller than the threshold value.

The 2nd viewpoint of this invention is related with the control apparatus of the motor | power_engine which drives a pump. The control device includes: a rotation speed detection unit that detects a rotation speed of the prime mover; and a rotation speed that controls the rotation speed of the prime mover so that the rotation speed detected by the rotation speed detection unit approaches a target rotation speed. A control unit, a load detection unit for detecting the load of the prime mover, and the rotation speed decreases when the load increases, the rotation speed increases when the load decreases, and an upper limit value of the load is determined. A target rotational speed adjusting unit that adjusts the target rotational speed in accordance with a detected value of the load in the load detecting unit so as to approach a predetermined relationship between the load and the rotational speed.

Preferably, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the predetermined rotational speed corresponding to the detected value of the load in the predetermined relationship; A difference from the target rotational speed being set in the rotational speed control unit is calculated, and if the calculated difference exceeds a predetermined threshold value, a range from the predetermined rotational speed to the target rotational speed being set is set. A new target rotational speed that is included and has a difference from the predetermined rotational speed smaller than the calculated difference is set in the rotational speed control unit.

A third aspect of the present invention relates to a control method for a prime mover that drives a pump. The control method includes a first step of detecting the rotational speed of the prime mover, and a second step of controlling the rotational speed of the prime mover so that the rotational speed detected in the first step approaches a target rotational speed. The third step of detecting the load of the prime mover, the rotation speed becomes slow when the load becomes large, the rotation speed becomes fast when the load becomes small, and an upper limit value of the load is determined, And a fourth step of adjusting the target rotational speed of the second step in accordance with the detected value of the load in the third step so as to approach a predetermined relationship between the load and the rotational speed.

Preferably, in the fourth step, when the adjustment of the target rotational speed according to the detected value of the load is performed, a predetermined rotational speed corresponding to the detected value of the load in the predetermined relationship; Calculating a difference with the target rotational speed being set in the process, and if the calculated difference exceeds a predetermined threshold, it is included in a range from the predetermined rotational speed to the target rotational speed being set; In addition, a rotation speed whose difference from the predetermined rotation speed is smaller than the calculated difference is set as a new target rotation speed in the second step.

  According to the present invention, when the load increases, the rotational speed decreases, and when the load decreases, the rotational speed increases, and the rotational speed is controlled so that the load does not exceed a predetermined upper limit. Performance can be improved over a wide operating range from low pressure / high flow rate operation range to high pressure / low flow rate operation range.

It is a figure which shows an example of the external appearance of the pump apparatus which concerns on embodiment of this invention. It is a figure which illustrates the internal structure of the pump part in the pump apparatus shown in FIG. It is a figure which shows an example of a structure of the control system in the pump apparatus which concerns on embodiment of this invention. It is a graph showing the relationship between the throttle opening and the rotation speed. It is a flowchart for demonstrating the adjustment operation of the rotational speed from the start of a pump to a stop. It is a flowchart for demonstrating the operation | movement in connection with adjustment of a target rotational speed. It is a figure for demonstrating the example which adjusts a target rotational speed so that the relationship between a predetermined load and rotational speed may be approached. It is a flowchart for demonstrating operation | movement when load exceeds an upper limit. 5 is a flowchart for explaining an operation when a load is smaller than an upper limit value and a target rotation speed is slower than a minimum rotation speed in FIG. 4. 4 is a graph showing the relationship between the discharge flow rate Q and the head H, and the relationship between the discharge flow rate Q and the throttle opening S. It is a flowchart for demonstrating adjustment operation | movement of rotational speed in the pump apparatus which concerns on other embodiment of this invention.

  Drawing 1 is a figure showing an example of the appearance of the pump device concerning the embodiment of the present invention. The pump device shown in FIG. 1 has a pump unit 10 and a prime mover 20. The pump unit 10 and the prime mover 20 are fixed in the frame 5.

  A prime mover 20 shown in FIG. 1 is an engine as an internal combustion engine. The prime mover 20 (engine) includes a device (such as an electronic governor) that adjusts the opening degree (throttle opening degree) of a throttle valve disposed in the intake passage so that a target rotational speed can be obtained.

  The pump unit 10 shown in FIG. 1 is a spiral centrifugal pump. FIG. 2 shows an example of the internal configuration of the pump unit 10. The pump unit 10 includes an impeller 14 coupled to a rotating shaft 21 of a prime mover 20 and a spiral casing 13 that houses the impeller 14. When the impeller 14 rotates, the water (fluid) in the suction port 11 is conveyed to the discharge port 12 through the spiral casing 13.

  The pump unit 10 is, for example, a self-priming pump, and can start the pump operation even when air is accumulated in the suction-side piping by being started with priming water inside. The filling tap 15 is used to fill the inside of the pump unit 10 with priming water at the time of starting.

FIG. 3 is a diagram illustrating a configuration example of a control system of the pump device according to the embodiment of the present invention.
In the example of FIG. 3, the pump device includes a rotation speed detection unit 30 that detects the rotation speed of the prime mover 20, a load detection unit 40 that detects a load of the prime mover 20 (power necessary for driving the rotary shaft 21), and a control. Part 50.

  For example, the rotation speed detection unit 30 converts a magnetic flux change of a magnet that rotates in conjunction with a gear inside the prime mover 20 into a pulse signal by a Hall sensor, and detects the rotation speed based on the frequency of the pulse signal.

  The load detection unit 40 is, for example, a sensor that detects the opening (throttle opening) of a throttle valve disposed in the intake passage of the prime mover 20 as a signal related to the load of the prime mover 20. This sensor includes, for example, a potentiometer.

  The control unit 50 is a device that controls the operation of the prime mover 20 and includes, for example, a microcomputer. The control unit 50 drives an actuator that adjusts the throttle valve and choke valve of the prime mover 20 in accordance with signals from the rotation speed detection unit 30 and the load detection unit 40 to obtain an appropriate rotation speed according to the load state. To control.

The control unit 50 includes a rotation speed control unit 51 and a target rotation speed adjustment unit 52 as functional components related to rotation speed control.
The rotation speed control unit 51 controls the rotation speed of the prime mover 20 so that the rotation speed detected by the rotation speed detection unit 30 approaches the target rotation speed Rt.
The target rotation speed adjustment unit 52 sets the load detection value (throttle opening S) in the load detection unit 40 so that the relationship between the load and the rotation speed of the prime mover 20 approaches a predetermined relationship (FIG. 4). Accordingly, the target rotational speed Rt is adjusted.

FIG. 4 is a graph showing the relationship between the throttle opening S and the rotation speed Ra. The rotational speed Ra in FIG. 4 indicates the rotational speed of the prime mover 20 determined with respect to the throttle opening S detected by the load detection unit 40. In the example of FIG. 4, the rotational speed Ra is determined so as to decrease substantially in proportion to the throttle opening S. The throttle opening S has, for example, a numerical range from “0” to “95”, where “0” indicates the fully closed state of the throttle valve and “95” indicates the fully open state.
The target rotation speed adjustment unit 52 may calculate the value of the rotation speed Ra corresponding to the throttle opening S based on, for example, a predetermined calculation formula, or correspond the throttle opening S and the rotation speed Ra. Then, it may be read from the data table stored in the storage device.

  The target rotation speed adjustment unit 52 adjusts the target rotation speed Rt so as to approach the relationship between the throttle opening S and the rotation speed Ra shown in FIG. In other words, the target rotational speed adjustment unit 52 adjusts the target rotational speed Rt so that the rotational speed decreases when the load of the prime mover 20 increases, and the rotational speed increases when the load decreases. Further, the target rotational speed adjustment unit 52 adjusts the target rotational speed Rt so that the load of the prime mover 20 does not exceed a predetermined upper limit value (throttle opening S = 80).

  Further, when a signal from a switch (not shown) for instructing the start of the pump unit 10 is input to the control unit 50, the target rotation speed adjustment unit 52 is related to the throttle opening S and the rotation speed Ra shown in FIG. The target rotational speed Rt (for example, 4000 rpm) for self-priming operation, which is faster than the fastest rotational speed (3800 rpm) in the above, is set in the rotational speed control unit 51 (self-priming operation mode).

  After setting a high target rotation speed Rt for self-priming operation in the rotation speed control unit 51, the target rotation speed adjustment unit 52 compares the throttle opening S detected by the load detection unit 40 with a predetermined lower limit value. . When the throttle opening S exceeds this lower limit value, the target rotation speed adjustment unit 52 rotates from the self-priming operation mode in which a high target rotation speed Rt for self-priming operation is set to the throttle opening S and rotation shown in FIG. The operation mode (normal operation mode) for adjusting the target rotation speed Rt so as to approach the relationship with the speed Ra is shifted to.

  However, if the throttle opening S is smaller than a predetermined lower limit value even after a fixed time has elapsed since the target rotational speed Rt for self-priming operation is set in the rotational speed control section 51, the target rotational speed adjustment section 52 The rotation of the prime mover 20 is stopped. This prevents the self-priming mode from continuing for a long period of time and causing an excessive burden on the prime mover 20 and the pump unit 10 due to the high rotational speed state.

  When shifting from the self-priming operation mode to the normal operation mode, the target rotation speed adjustment unit 52 corresponds to the throttle opening S detected by the load detection unit 40 in the relationship between the throttle opening S and the rotation speed Ra shown in FIG. The predetermined rotational speed Ra is acquired, and a difference DR between the target rotational speed Rt currently set in the rotational speed control unit 51 and the rotational speed Ra is calculated. The target rotational speed adjustment unit 52 compares the difference DR with a predetermined threshold value, and if the difference DR exceeds the threshold value (the target rotational speed Rt is away from the rotational speed Ra), the target currently being set A new target rotation speed Rt closer to the rotation speed Ra than the rotation speed Rt is set in the rotation speed control unit 51. That is, the target rotational speed adjustment unit 52 is a new target rotational speed that is included in the range from the rotational speed Ra to the current target rotational speed Rt and that has a difference from the rotational speed Ra that is smaller than the current target rotational speed Rt. Rt is set in the rotation speed control unit 51. For example, the target rotational speed adjustment unit 52 sets an intermediate rotational speed in the range from the rotational speed Ra to the current target rotational speed Rt as the new target rotational speed Rt in the rotational speed control unit 51 (FIG. 7).

  When the throttle opening S of the load detection unit 40 exceeds the upper limit value (80) in the normal operation mode, the target rotational speed adjustment unit 52 causes the throttle opening S of the load detection unit 40 to be smaller than the upper limit value (80). Until the target rotational speed Rt is decreased. For example, the target rotational speed adjustment unit 52 performs a process of decelerating the target rotational speed Rt by a predetermined change amount according to a comparison result between the throttle opening S and the upper limit value (80). ) Repeat until smaller. The target rotational speed Rt may be reduced by, for example, subtracting a constant speed from the original speed, or by reducing the overall speed by a constant rate.

  Next, the rotation speed adjustment operation in the pump apparatus having the above-described configuration will be described with reference to a flowchart.

FIG. 5 is a flowchart for explaining the operation of adjusting the rotational speed from the start to the stop of the pump.
When a signal from a switch or the like (not shown) for instructing start of the pump unit 10 is input to the control unit 50 (ST105), the target rotation speed adjustment unit 52 sets the high target rotation speed Rt for self-priming operation to the rotation speed. The control unit 51 is set (ST125). Accordingly, the pump device starts operation at a high rotational speed for self-priming operation (self-priming operation mode).
On the other hand, when the pump is not started (for example, in the case of restarting or the like), the target rotation speed adjustment unit 52 proceeds to step ST140 described later.

  When the rotational speed of the prime mover 20 reaches the target rotational speed Rt for self-priming operation by the control of the rotational speed control section 51, the target rotational speed adjustment section 52 acquires the throttle opening S from the load detection section 40 (ST130). This is compared with a predetermined lower limit value (ST135). In the self-priming operation, the load on the prime mover 20 is significantly reduced, so that the throttle opening S is lower than the lower limit value.

  When the throttle opening S is smaller than the lower limit (when the self-priming operation continues), the target rotational speed adjustment unit 52 sets the target rotational speed Rt for the self-priming operation in the rotational speed control unit 51. It is determined whether or not the elapsed time has reached a certain time (ST180). When the elapsed time (time in the self-priming operation mode) is shorter than the predetermined time, the target rotational speed adjustment unit 52 returns to step ST130 and repeats the determination of whether or not the throttle opening S exceeds the lower limit value. When the elapsed time reaches a certain time, the target rotational speed adjustment unit 52 proceeds to step ST155 and stops the rotation of the prime mover 20. As a result, it is possible to prevent a high rotation speed in the self-priming operation mode from continuing for a long time and applying an excessive burden to the prime mover 20 and the pump unit 10.

  When the throttle opening S becomes larger than a predetermined lower limit value (when the self-priming operation ends and the pumping of water starts), the target rotational speed adjustment unit 52 shifts to the normal operation mode. The target rotation speed adjustment unit 52 sets the target rotation speed Rt to a predetermined initial value (eg, 3600 rpm) (ST140), and starts adjusting the target rotation speed according to the throttle opening S of the load detection unit 40 (ST145). ). In a normal operation mode, when a signal from a switch (not shown) that instructs to stop the pump is input to the control unit 50 (ST150), the target rotation speed adjustment unit 52 stops the rotation of the prime mover 20.

FIG. 6 is a flowchart showing details of the process in step ST145 of FIG. 5, and shows operations related to the adjustment of the target rotational speed Rt in the normal operation mode.
The target rotational speed adjustment unit 52 acquires the throttle opening S from the load detection unit 40 (ST205), and determines whether the throttle opening S is larger than the upper limit value (80) (ST210). When the throttle opening S is larger than the upper limit (80), the target rotational speed adjustment unit 52 proceeds to step ST305 (FIG. 8) described later. Further, it is determined whether or not the target rotational speed Rt currently set in the rotational speed control unit 51 is slower than the lowest rotational speed (3600 rpm) in the graph shown in FIG. The process proceeds to step ST405 (FIG. 9).

  When the throttle opening S is smaller than the upper limit value (80) and the target rotational speed Rt is faster than the lowest rotational speed (3600 rpm) in the graph shown in FIG. 4, the target rotational speed adjustment unit 52 is acquired in step ST205. A predetermined rotational speed Ra (FIG. 4) corresponding to the throttle opening S is acquired (ST220), and a difference DR between the target rotational speed Rt and the rotational speed Ra is calculated (ST225). When the difference DR is larger than the threshold value, the target rotational speed adjustment unit 52 sets the intermediate value between the target rotational speed Rt and the rotational speed Ra as a new target rotational speed Rt in the rotational speed control unit 51 (ST235). . When the difference DR is smaller than the threshold value, the target rotation speed adjustment unit 52 maintains the target rotation speed Rt being set.

  FIG. 7 is a diagram for explaining an example of adjusting the target rotational speed Rt so as to approach the relationship between the load (throttle opening S) and the rotational speed shown in the graph of FIG. The graph shown in FIG. 7 represents a part of the graph shown in FIG. “P1” to “P3” in FIG. 7 indicate operating points of the prime mover 20 represented by the throttle opening S and the target rotational speed Rt.

  The rotational speed Ra1 determined corresponding to the throttle opening S1 at the operating point P1 is faster than the target rotational speed Rt1 at the operating point P1, and the difference DR is larger than the threshold value. Therefore, an intermediate value Rt2 between the rotational speed Ra1 and the target rotational speed Rt1 is set as a new target rotational speed (ST235).

  Since the new target rotational speed Rt2 is faster than the original target rotational speed Rt1, the load on the prime mover 20 increases. Therefore, by changing the target rotational speed from “Rt1” to “Rt2”, the throttle opening becomes “S2” which is larger than the original “S1”. That is, the new operating point P2 (S2, Rt2) moves in the upper right direction of the original operating point P1 (S1, Rt1). As shown in FIG. 7, the operation P2 is closer to a graph line representing the relationship between the load (throttle opening S) and the rotation speed than the original operation point P1.

  In the example of FIG. 7, the operating point moves from “P2” to “P3” by further adjusting the target rotational speed Rt. Similarly to the above, the target rotational speed Rt3 at the operating point P3 is obtained as an intermediate value between the rotational speed Ra2 corresponding to the throttle opening S2 at the operating point P2 and the target rotational speed Rt2. The operating point P3 is closer to the line on the graph than the operating point P2.

  As described above, by repeating the processes of steps ST205 to ST235, the rotational speed of the prime mover 20 approaches the relationship between the load and the rotational speed shown in the graph of FIG. 4 until the difference DR becomes smaller than a predetermined threshold value. To be controlled.

FIG. 8 is a flowchart for explaining the operation when the load (throttle opening S) detected by the load detector 40 exceeds the upper limit value (80).
When it is determined in step ST210 (FIG. 6) that the throttle opening S is larger than the upper limit value (80), the target rotational speed adjustment unit 52 sets the target rotational speed Rt set in the rotational speed control unit 51 to 3600 rpm (FIG. 6). 4 is determined whether it is faster than the minimum rotational speed in the graph shown in FIG. 4 (ST305). When the target rotation speed Rt is slower than 3600 rpm, the target rotation speed adjustment unit 52 sets a new target rotation speed Rt obtained by decelerating the target rotation speed Rt by a predetermined change in the rotation speed control unit 51 (ST325).

  On the other hand, when target rotation speed Rt is faster than 3600 rpm, target rotation speed adjustment unit 52 sets target rotation speed Rt to 3600 rpm (ST310). When the rotational speed of the prime mover 20 reaches 3600 rpm, the target rotational speed adjustment unit 52 acquires the throttle opening S of the load detection unit 40 again (ST315) and compares it with the upper limit value (80) (ST320). If the throttle opening S exceeds the upper limit (80) even if the rotation speed is set to 3600 rpm, the target rotation speed adjustment unit 52 reduces the target rotation speed Rt by a predetermined change amount to a new target rotation speed Rt. Is set in the rotation speed control unit 51 (ST325).

By repeating the processes of steps ST305 to ST325 described above, the target rotational speed Rt of the prime mover 20 is decelerated until the throttle opening S becomes smaller than the upper limit value (80).
In the process shown in the flowchart of FIG. 8, when the load (throttle opening S) exceeds the upper limit (80) at a rotational speed faster than the lowest rotational speed (3600 rpm) in the graph shown in FIG. Rt is immediately decelerated to the lowest rotational speed (3600 rpm). Thereby, the time which an excessive load is applied to the prime mover 20 can be shortened.

9 shows a case where the load (throttle opening S) detected by the load detector 40 is smaller than the upper limit value (80) and the target rotational speed Rt is slower than the lowest rotational speed (3600 rpm) in FIG. It is a flowchart for demonstrating operation | movement.
In this case, the target rotational speed adjustment unit 52 calculates a difference DS between the throttle opening S detected by the load detection unit 40 and the upper limit value (80) (ST405), and this difference DS is calculated from a predetermined threshold value. It is determined whether it is larger (ST410). When the difference DS is larger than a predetermined threshold value, the target rotational speed adjustment unit 52 sets a new target rotational speed Rt obtained by increasing the target rotational speed Rt by a predetermined change in the rotational speed control unit 51 ( ST415). The target rotational speed Rt may be increased by, for example, adding a constant speed to the original speed, or by increasing the overall speed by a constant rate.

  By repeating the processes of steps ST405 to ST415 described above, the target rotational speed Rt of the prime mover 20 is increased until the difference DS between the throttle opening S and the upper limit value (80) becomes smaller than a predetermined threshold value. .

FIG. 10 is a graph showing an example of the performance of the pump device. Curves CV1 and CV2 represent the relationship between the discharge flow rate Q and the head H, and the curve CV3 represents the relationship between the discharge flow rate Q and the throttle opening S.
A curved line CV1 indicated by a dotted line represents characteristics when the rotational speed of the prime mover is maintained at a rated speed (3600 rpm), and a curved line CV2 indicated by a solid line shows the relationship between the load (throttle opening S) and the target rotational speed Rt. The characteristic at the time of performing the control mentioned above so that the relationship shown in 4 may be approximated is represented.
As can be seen by comparing the curves CV1 and CV2, the head H at the same discharge water amount Q is increased by controlling the target rotational speed Rt. Further, the load (throttle opening S) is restricted so as not to exceed the upper limit (80) in the operation region where the discharged water amount Q is larger than 300 [liter / min].

  As described above, according to the pump device according to the present embodiment, when the load of the prime mover 20 that drives the pump unit 10 is increased, the rotation speed is decreased, and when the load is decreased, the rotation speed is increased. The rotational speed of the prime mover 20 is controlled so that does not exceed a predetermined upper limit. Therefore, as shown in the graph of FIG. 10, the performance is improved over a wide operating range from the low pressure / large flow rate operation range to the high pressure / small flow rate operation range, compared to the conventional method of keeping the rotation speed of the prime mover constant. it can.

  Further, according to the pump device according to the present embodiment, in the self-priming operation mode at the time of starting the pump, since the rotational speed of the prime mover 20 is made higher than that in the normal operation mode, the substantial pump operation is started. Time can be shortened. Further, whether or not the self-priming operation has ended is determined based on the load of the prime mover 20 (throttle opening S), and when the end of the self-priming operation is determined, the mode automatically shifts to the normal operation mode. The pump operation can be started. Moreover, since the rotation of the prime mover 20 is stopped when the self-priming operation mode continues for a certain time, the excessive load on the prime mover 20 and the pump unit 10 due to the high rotational speed for the self-priming operation continues for a long time. It can be effectively prevented.

  In addition, this invention is not limited to embodiment mentioned above, Various modifications are included.

FIG. 11 is a flowchart for explaining a rotation speed adjusting operation in a pump device according to another embodiment of the present invention.
The flowchart shown in FIG. 11 is obtained by adding steps ST110 to ST120 between step ST105 and step ST125 in the flowchart shown in FIG.
In this case, the target rotational speed adjusting unit 52 receives an input of the pump start signal and sets the target rotational speed Rt to a high rotational speed (for example, 4000 rpm) for self-priming operation, so that the rotational speed slower than this is set. (For example, 3600 rpm) is set in the rotational speed control unit 51 as the initial target rotational speed Rt (ST110). Then, the target rotational speed adjustment unit 52 acquires the throttle opening S of the load detection unit 40 at this initial rotational speed (ST115), and determines whether the throttle opening S is smaller than a predetermined lower limit value (ST115). ST120). When the throttle opening S is smaller than the lower limit value, the target rotational speed adjustment unit 52 sets the target rotational speed Rt to a high rotational speed for self-priming operation (ST125).
As described above, according to the processing of the flowchart of FIG. 11, since the self-priming operation is confirmed at a relatively low rotational speed and then the rotational speed is changed to a high rotational speed, an excessive load is applied to the prime mover 20 and the pump unit 10. Can be effectively prevented.

  In the embodiment described above, the difference DR between the rotation speed Ra (FIG. 4) corresponding to the load detection value and the target rotation speed Rt in the normal operation mode in which the load detection value (throttle opening) is smaller than the upper limit value (80). Is larger than a predetermined threshold value, the rotational speed intermediate between the rotational speed Ra and the target rotational speed Rt is set as a new target rotational speed Rt (ST235, FIG. 6), but the present invention is limited to this. Not. That is, the new target rotational speed Rt is included in the range from the rotational speed Ra corresponding to the load detection value to the original target rotational speed Rt, and the difference DR from the rotational speed Ra is the original target rotational speed Rt. The rotation speed may be any lower speed than that of the rotation speed, and is not limited to an intermediate value between the rotation speed Ra and the target rotation speed Rt as described above.

  In embodiment mentioned above, although the case where the pump part 10 is a centrifugal pump is mentioned as an example, this invention is not limited to this. Various types of pumps other than centrifugal pumps may be used in the pump unit of the present invention.

  In the embodiment described above, a case where the prime mover 20 is an engine (reciprocating engine) is taken as an example, but the present invention is not limited to this. Various types of internal combustion engines may be used for the prime mover of the present invention. For example, an electric motor may be used as a power source other than the internal combustion engine.

DESCRIPTION OF SYMBOLS 5 ... Frame, 10 ... Pump part, 11 ... Suction port, 12 ... Discharge port, 13 ... Spiral casing, 14 ... Impeller, 15 ... Water filling stopper, 20 ... Motor | power_engine, 21 ... Rotating shaft, 30 ... Rotation speed detection part, DESCRIPTION OF SYMBOLS 40 ... Load detection part, 50 ... Control part, 51 ... Rotational speed control part, 52 ... Target rotational speed adjustment part.

  The present invention relates to a pump device provided with a prime mover for driving, and more particularly to a pump device having improved performance in an operation region where discharge pressure is high and flow rate is low.

  In general, a centrifugal centrifugal pump is a load (power required to drive a rotating shaft) in an operating region where the pressure is high and the amount of water is low (when the distance to the drainage site, the head is long, or when the discharge port is throttled). In contrast, it is known that the load is large in an operation region where the pressure is low and the amount of water is large (see the following patent document).

JP 2000-227084 A

  The prime mover used to drive the pump must be selected to meet the maximum power required for operation. In the case of the centrifugal centrifugal pump, since it has the above characteristics, the prime mover is selected in accordance with the maximum load at a low pressure and a large flow rate. However, even if a prime mover with large power is selected for low pressure and large flow rate, the power becomes excessive at high pressure and small flow rate. That is, although a prime mover with high power is selected, the power does not contribute to the performance of the pump in the high pressure / low flow operation region, and is wasted.

  The present invention has been made in view of such circumstances, and its purpose is wide from a low pressure / high flow rate operation region to a high pressure / low flow rate operation region while suppressing the rated output of the prime mover used to drive the pump. An object of the present invention is to provide a pump device capable of improving performance in the operating range.

Pump device according to the present onset Ming, a pump unit, and a prime mover for driving the pump portion, a rotation speed detector for detecting the rotational speed of the prime mover, the rotational speed of the target to be detected in the rotation speed detecting unit A rotation speed control unit that controls the rotation speed of the prime mover so as to approach the rotation speed, a load detection unit that detects a load on the prime mover, and the rotation speed becomes slower and the load becomes smaller as the load increases. According to the detected value of the load in the load detection unit so as to approach a predetermined relationship between the load and the rotational speed, where the rotational speed is increased and an upper limit value of the load is determined. A target rotation speed adjusting unit that adjusts the target rotation speed.

In the first aspect of the present invention, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, a predetermined value corresponding to the detected value of the load in the predetermined relationship. And the target rotational speed being set in the rotational speed control unit, and if the calculated difference exceeds a predetermined threshold, the target being set from the predetermined rotational speed is calculated. A new target rotation speed that is included in the range up to the rotation speed and that is smaller than the calculated difference is set in the rotation speed control unit.
For example, the target rotation speed adjustment unit sets an intermediate rotation speed in the range from the predetermined rotation speed to the target rotation speed being set to the rotation speed control unit as the new target rotation speed.

In the second aspect of the present invention, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the detected value of the load exceeds the upper limit value, and If the target rotational speed being set in the rotational speed control unit is faster than the minimum rotational speed defined in the predetermined relationship, the minimum rotational speed is set as the target rotational speed in the rotational speed control unit, If the detected load value exceeds the upper limit value even after the setting, the target rotational speed is decreased by a predetermined change amount until the detected load value becomes smaller than the upper limit value.

In the third aspect of the present invention, when the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the target rotational speed set in the rotational speed control unit is If it is slower than the minimum rotational speed defined in the predetermined relationship, the detected value of the load is smaller than the upper limit value, and the difference between the detected value of the load and the upper limit value exceeds a predetermined threshold value The target rotation speed is increased until the difference between the load detection value and the upper limit value becomes smaller than the threshold value.

Preferably, the pump unit is a self-priming pump, and the target rotation speed adjusting unit receives a signal instructing start of the pump unit from a maximum rotation speed defined in the predetermined relationship. The target rotational speed for the fast self-priming operation is set in the rotational speed control section.

Preferably, the target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then compares the detected value of the load with a predetermined lower limit value to detect the load. If the value exceeds the lower limit value, the adjustment of the target rotational speed according to the detected value of the load is performed.

Preferably, the target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then the state where the detected value of the load is smaller than the lower limit value continues for a certain period of time. The rotation of the prime mover is stopped.

Preferably, when the target rotational speed adjustment unit receives a signal instructing start of the pump unit, the target rotational speed adjustment unit sets an initial target rotational speed slower than the target rotational speed for the self-priming operation in the rotational speed control unit. After the setting, the load detection value is compared with the lower limit value, and if the load detection value is smaller than the lower limit value, the target rotation speed for the self-priming operation is transferred to the rotation speed control unit. Set.

  According to the present invention, when the load increases, the rotational speed decreases, and when the load decreases, the rotational speed increases, and the rotational speed is controlled so that the load does not exceed a predetermined upper limit. Performance can be improved over a wide operating range from low pressure / high flow rate operation range to high pressure / low flow rate operation range.

It is a figure which shows an example of the external appearance of the pump apparatus which concerns on embodiment of this invention. It is a figure which illustrates the internal structure of the pump part in the pump apparatus shown in FIG. It is a figure which shows an example of a structure of the control system in the pump apparatus which concerns on embodiment of this invention. It is a graph showing the relationship between the throttle opening and the rotation speed. It is a flowchart for demonstrating the adjustment operation of the rotational speed from the start of a pump to a stop. It is a flowchart for demonstrating the operation | movement in connection with adjustment of a target rotational speed. It is a figure for demonstrating the example which adjusts a target rotational speed so that the relationship between a predetermined load and rotational speed may be approached. It is a flowchart for demonstrating operation | movement when load exceeds an upper limit. 5 is a flowchart for explaining an operation when a load is smaller than an upper limit value and a target rotation speed is slower than a minimum rotation speed in FIG. 4. 4 is a graph showing the relationship between the discharge flow rate Q and the head H, and the relationship between the discharge flow rate Q and the throttle opening S. It is a flowchart for demonstrating adjustment operation | movement of rotational speed in the pump apparatus which concerns on other embodiment of this invention.

  Drawing 1 is a figure showing an example of the appearance of the pump device concerning the embodiment of the present invention. The pump device shown in FIG. 1 has a pump unit 10 and a prime mover 20. The pump unit 10 and the prime mover 20 are fixed in the frame 5.

  A prime mover 20 shown in FIG. 1 is an engine as an internal combustion engine. The prime mover 20 (engine) includes a device (such as an electronic governor) that adjusts the opening degree (throttle opening degree) of a throttle valve disposed in the intake passage so that a target rotational speed can be obtained.

  The pump unit 10 shown in FIG. 1 is a spiral centrifugal pump. FIG. 2 shows an example of the internal configuration of the pump unit 10. The pump unit 10 includes an impeller 14 coupled to a rotating shaft 21 of a prime mover 20 and a spiral casing 13 that houses the impeller 14. When the impeller 14 rotates, the water (fluid) in the suction port 11 is conveyed to the discharge port 12 through the spiral casing 13.

  The pump unit 10 is, for example, a self-priming pump, and can start the pump operation even when air is accumulated in the suction-side piping by being started with priming water inside. The filling tap 15 is used to fill the inside of the pump unit 10 with priming water at the time of starting.

FIG. 3 is a diagram illustrating a configuration example of a control system of the pump device according to the embodiment of the present invention.
In the example of FIG. 3, the pump device includes a rotation speed detection unit 30 that detects the rotation speed of the prime mover 20, a load detection unit 40 that detects a load of the prime mover 20 (power necessary for driving the rotary shaft 21), and a control. Part 50.

  For example, the rotation speed detection unit 30 converts a magnetic flux change of a magnet that rotates in conjunction with a gear inside the prime mover 20 into a pulse signal by a Hall sensor, and detects the rotation speed based on the frequency of the pulse signal.

  The load detection unit 40 is, for example, a sensor that detects the opening (throttle opening) of a throttle valve disposed in the intake passage of the prime mover 20 as a signal related to the load of the prime mover 20. This sensor includes, for example, a potentiometer.

  The control unit 50 is a device that controls the operation of the prime mover 20 and includes, for example, a microcomputer. The control unit 50 drives an actuator that adjusts the throttle valve and choke valve of the prime mover 20 in accordance with signals from the rotation speed detection unit 30 and the load detection unit 40 to obtain an appropriate rotation speed according to the load state. To control.

The control unit 50 includes a rotation speed control unit 51 and a target rotation speed adjustment unit 52 as functional components related to rotation speed control.
The rotation speed control unit 51 controls the rotation speed of the prime mover 20 so that the rotation speed detected by the rotation speed detection unit 30 approaches the target rotation speed Rt.
The target rotation speed adjustment unit 52 sets the load detection value (throttle opening S) in the load detection unit 40 so that the relationship between the load and the rotation speed of the prime mover 20 approaches a predetermined relationship (FIG. 4). Accordingly, the target rotational speed Rt is adjusted.

FIG. 4 is a graph showing the relationship between the throttle opening S and the rotation speed Ra. The rotational speed Ra in FIG. 4 indicates the rotational speed of the prime mover 20 determined with respect to the throttle opening S detected by the load detection unit 40. In the example of FIG. 4, the rotational speed Ra is determined so as to decrease substantially in proportion to the throttle opening S. The throttle opening S has, for example, a numerical range from “0” to “95”, where “0” indicates the fully closed state of the throttle valve and “95” indicates the fully open state.
The target rotation speed adjustment unit 52 may calculate the value of the rotation speed Ra corresponding to the throttle opening S based on, for example, a predetermined calculation formula, or correspond the throttle opening S and the rotation speed Ra. Then, it may be read from the data table stored in the storage device.

  The target rotation speed adjustment unit 52 adjusts the target rotation speed Rt so as to approach the relationship between the throttle opening S and the rotation speed Ra shown in FIG. In other words, the target rotational speed adjustment unit 52 adjusts the target rotational speed Rt so that the rotational speed decreases when the load of the prime mover 20 increases, and the rotational speed increases when the load decreases. Further, the target rotational speed adjustment unit 52 adjusts the target rotational speed Rt so that the load of the prime mover 20 does not exceed a predetermined upper limit value (throttle opening S = 80).

  Further, when a signal from a switch (not shown) for instructing the start of the pump unit 10 is input to the control unit 50, the target rotation speed adjustment unit 52 is related to the throttle opening S and the rotation speed Ra shown in FIG. The target rotational speed Rt (for example, 4000 rpm) for self-priming operation, which is faster than the fastest rotational speed (3800 rpm) in the above, is set in the rotational speed controller 51 (self-priming operation mode).

  After setting a high target rotation speed Rt for self-priming operation in the rotation speed control unit 51, the target rotation speed adjustment unit 52 compares the throttle opening S detected by the load detection unit 40 with a predetermined lower limit value. . When the throttle opening S exceeds this lower limit value, the target rotation speed adjustment unit 52 rotates from the self-priming operation mode in which a high target rotation speed Rt for self-priming operation is set to the throttle opening S and rotation shown in FIG. The operation mode (normal operation mode) for adjusting the target rotation speed Rt so as to approach the relationship with the speed Ra is shifted to.

  However, if the throttle opening S is smaller than a predetermined lower limit value even after a fixed time has elapsed since the target rotational speed Rt for self-priming operation is set in the rotational speed control section 51, the target rotational speed adjustment section 52 The rotation of the prime mover 20 is stopped. This prevents the self-priming mode from continuing for a long period of time and causing an excessive burden on the prime mover 20 and the pump unit 10 due to the high rotational speed state.

  When shifting from the self-priming operation mode to the normal operation mode, the target rotation speed adjustment unit 52 corresponds to the throttle opening S detected by the load detection unit 40 in the relationship between the throttle opening S and the rotation speed Ra shown in FIG. The predetermined rotational speed Ra is acquired, and a difference DR between the target rotational speed Rt currently set in the rotational speed control unit 51 and the rotational speed Ra is calculated. The target rotational speed adjustment unit 52 compares the difference DR with a predetermined threshold value, and if the difference DR exceeds the threshold value (the target rotational speed Rt is away from the rotational speed Ra), the target currently being set A new target rotation speed Rt closer to the rotation speed Ra than the rotation speed Rt is set in the rotation speed control unit 51. That is, the target rotational speed adjustment unit 52 is a new target rotational speed that is included in the range from the rotational speed Ra to the current target rotational speed Rt and that has a difference from the rotational speed Ra that is smaller than the current target rotational speed Rt. Rt is set in the rotation speed control unit 51. For example, the target rotational speed adjustment unit 52 sets an intermediate rotational speed in the range from the rotational speed Ra to the current target rotational speed Rt as the new target rotational speed Rt in the rotational speed control unit 51 (FIG. 7).

  When the throttle opening S of the load detection unit 40 exceeds the upper limit value (80) in the normal operation mode, the target rotational speed adjustment unit 52 causes the throttle opening S of the load detection unit 40 to be smaller than the upper limit value (80). Until the target rotational speed Rt is decreased. For example, the target rotational speed adjustment unit 52 performs a process of decelerating the target rotational speed Rt by a predetermined change amount according to a comparison result between the throttle opening S and the upper limit value (80). ) Repeat until smaller. The target rotational speed Rt may be reduced by, for example, subtracting a constant speed from the original speed, or by reducing the overall speed by a constant rate.

  Next, the rotation speed adjustment operation in the pump apparatus having the above-described configuration will be described with reference to a flowchart.

FIG. 5 is a flowchart for explaining the operation of adjusting the rotational speed from the start to the stop of the pump.
When a signal from a switch or the like (not shown) for instructing start of the pump unit 10 is input to the control unit 50 (ST105), the target rotation speed adjustment unit 52 sets the high target rotation speed Rt for self-priming operation to the rotation speed. The control unit 51 is set (ST125). Accordingly, the pump device starts operation at a high rotational speed for self-priming operation (self-priming operation mode).
On the other hand, when the pump is not started (for example, in the case of restarting or the like), the target rotation speed adjustment unit 52 proceeds to step ST140 described later.

  When the rotational speed of the prime mover 20 reaches the target rotational speed Rt for self-priming operation by the control of the rotational speed control section 51, the target rotational speed adjustment section 52 acquires the throttle opening S from the load detection section 40 (ST130). This is compared with a predetermined lower limit value (ST135). In the self-priming operation, the load on the prime mover 20 is significantly reduced, so that the throttle opening S is lower than the lower limit value.

  When the throttle opening S is smaller than the lower limit (when the self-priming operation continues), the target rotational speed adjustment unit 52 sets the target rotational speed Rt for the self-priming operation in the rotational speed control unit 51. It is determined whether or not the elapsed time has reached a certain time (ST180). When the elapsed time (time in the self-priming operation mode) is shorter than the predetermined time, the target rotational speed adjustment unit 52 returns to step ST130 and repeats the determination of whether or not the throttle opening S exceeds the lower limit value. When the elapsed time reaches a certain time, the target rotational speed adjustment unit 52 proceeds to step ST155 and stops the rotation of the prime mover 20. As a result, it is possible to prevent a high rotation speed in the self-priming operation mode from continuing for a long time and applying an excessive burden to the prime mover 20 and the pump unit 10.

  When the throttle opening S becomes larger than a predetermined lower limit value (when the self-priming operation ends and the pumping of water starts), the target rotational speed adjustment unit 52 shifts to the normal operation mode. The target rotation speed adjustment unit 52 sets the target rotation speed Rt to a predetermined initial value (eg, 3600 rpm) (ST140), and starts adjusting the target rotation speed according to the throttle opening S of the load detection unit 40 (ST145). ). In a normal operation mode, when a signal from a switch (not shown) that instructs to stop the pump is input to the control unit 50 (ST150), the target rotation speed adjustment unit 52 stops the rotation of the prime mover 20.

FIG. 6 is a flowchart showing details of the process in step ST145 of FIG. 5, and shows operations related to adjustment of the target rotational speed Rt in the normal operation mode.
The target rotational speed adjustment unit 52 acquires the throttle opening S from the load detection unit 40 (ST205), and determines whether the throttle opening S is larger than the upper limit value (80) (ST210). When the throttle opening S is larger than the upper limit (80), the target rotational speed adjustment unit 52 proceeds to step ST305 (FIG. 8) described later. Further, it is determined whether or not the target rotational speed Rt currently set in the rotational speed control unit 51 is slower than the lowest rotational speed (3600 rpm) in the graph shown in FIG. The process proceeds to step ST405 (FIG. 9).

  When the throttle opening S is smaller than the upper limit value (80) and the target rotational speed Rt is faster than the lowest rotational speed (3600 rpm) in the graph shown in FIG. 4, the target rotational speed adjustment unit 52 is acquired in step ST205. A predetermined rotational speed Ra (FIG. 4) corresponding to the throttle opening S is acquired (ST220), and a difference DR between the target rotational speed Rt and the rotational speed Ra is calculated (ST225). When the difference DR is larger than the threshold value, the target rotational speed adjustment unit 52 sets the intermediate value between the target rotational speed Rt and the rotational speed Ra as a new target rotational speed Rt in the rotational speed control unit 51 (ST235). . When the difference DR is smaller than the threshold value, the target rotation speed adjustment unit 52 maintains the target rotation speed Rt being set.

  FIG. 7 is a diagram for explaining an example of adjusting the target rotational speed Rt so as to approach the relationship between the load (throttle opening S) and the rotational speed shown in the graph of FIG. The graph shown in FIG. 7 represents a part of the graph shown in FIG. “P1” to “P3” in FIG. 7 indicate operating points of the prime mover 20 represented by the throttle opening S and the target rotational speed Rt.

  The rotational speed Ra1 determined corresponding to the throttle opening S1 at the operating point P1 is faster than the target rotational speed Rt1 at the operating point P1, and the difference DR is larger than the threshold value. Therefore, an intermediate value Rt2 between the rotational speed Ra1 and the target rotational speed Rt1 is set as a new target rotational speed (ST235).

  Since the new target rotational speed Rt2 is faster than the original target rotational speed Rt1, the load on the prime mover 20 increases. Therefore, by changing the target rotational speed from “Rt1” to “Rt2”, the throttle opening becomes “S2” which is larger than the original “S1”. That is, the new operating point P2 (S2, Rt2) moves in the upper right direction of the original operating point P1 (S1, Rt1). As shown in FIG. 7, the operation P2 is closer to a graph line representing the relationship between the load (throttle opening S) and the rotation speed than the original operation point P1.

  In the example of FIG. 7, the operating point moves from “P2” to “P3” by further adjusting the target rotational speed Rt. Similarly to the above, the target rotational speed Rt3 at the operating point P3 is obtained as an intermediate value between the rotational speed Ra2 corresponding to the throttle opening S2 at the operating point P2 and the target rotational speed Rt2. The operating point P3 is closer to the line on the graph than the operating point P2.

  As described above, by repeating the processes of steps ST205 to ST235, the rotational speed of the prime mover 20 approaches the relationship between the load and the rotational speed shown in the graph of FIG. 4 until the difference DR becomes smaller than a predetermined threshold value. To be controlled.

FIG. 8 is a flowchart for explaining the operation when the load (throttle opening S) detected by the load detector 40 exceeds the upper limit value (80).
When it is determined in step ST210 (FIG. 6) that the throttle opening S is larger than the upper limit value (80), the target rotational speed adjustment unit 52 sets the target rotational speed Rt set in the rotational speed control unit 51 to 3600 rpm (FIG. 6). 4 is determined whether it is faster than the minimum rotational speed in the graph shown in FIG. 4 (ST305). When the target rotation speed Rt is slower than 3600 rpm, the target rotation speed adjustment unit 52 sets a new target rotation speed Rt obtained by decelerating the target rotation speed Rt by a predetermined change in the rotation speed control unit 51 (ST325).

  On the other hand, when target rotation speed Rt is faster than 3600 rpm, target rotation speed adjustment unit 52 sets target rotation speed Rt to 3600 rpm (ST310). When the rotational speed of the prime mover 20 reaches 3600 rpm, the target rotational speed adjustment unit 52 acquires the throttle opening S of the load detection unit 40 again (ST315) and compares it with the upper limit value (80) (ST320). If the throttle opening S exceeds the upper limit (80) even if the rotation speed is set to 3600 rpm, the target rotation speed adjustment unit 52 reduces the target rotation speed Rt by a predetermined change amount to a new target rotation speed Rt. Is set in the rotation speed control unit 51 (ST325).

By repeating the processes of steps ST305 to ST325 described above, the target rotational speed Rt of the prime mover 20 is decelerated until the throttle opening S becomes smaller than the upper limit value (80).
In the process shown in the flowchart of FIG. 8, when the load (throttle opening S) exceeds the upper limit (80) at a rotational speed faster than the lowest rotational speed (3600 rpm) in the graph shown in FIG. Rt is immediately decelerated to the lowest rotational speed (3600 rpm). Thereby, the time which an excessive load is applied to the prime mover 20 can be shortened.

9 shows a case where the load (throttle opening S) detected by the load detector 40 is smaller than the upper limit value (80) and the target rotational speed Rt is slower than the lowest rotational speed (3600 rpm) in FIG. It is a flowchart for demonstrating operation | movement.
In this case, the target rotational speed adjustment unit 52 calculates a difference DS between the throttle opening S detected by the load detection unit 40 and the upper limit value (80) (ST405), and this difference DS is calculated from a predetermined threshold value. It is determined whether it is larger (ST410). When the difference DS is larger than a predetermined threshold value, the target rotational speed adjustment unit 52 sets a new target rotational speed Rt obtained by increasing the target rotational speed Rt by a predetermined change in the rotational speed control unit 51 ( ST415). The target rotational speed Rt may be increased by, for example, adding a constant speed to the original speed, or by increasing the overall speed by a constant rate.

  By repeating the processes of steps ST405 to ST415 described above, the target rotational speed Rt of the prime mover 20 is increased until the difference DS between the throttle opening S and the upper limit value (80) becomes smaller than a predetermined threshold value. .

FIG. 10 is a graph showing an example of the performance of the pump device. Curves CV1 and CV2 represent the relationship between the discharge flow rate Q and the head H, and the curve CV3 represents the relationship between the discharge flow rate Q and the throttle opening S.
A curved line CV1 indicated by a dotted line represents characteristics when the rotational speed of the prime mover is maintained at a rated speed (3600 rpm), and a curved line CV2 indicated by a solid line shows the relationship between the load (throttle opening S) and the target rotational speed Rt. The characteristic at the time of performing the control mentioned above so that the relationship shown in 4 may be approximated is represented.
As can be seen by comparing the curves CV1 and CV2, the head H at the same discharge water amount Q is increased by controlling the target rotational speed Rt. Further, the load (throttle opening S) is restricted so as not to exceed the upper limit (80) in the operation region where the discharged water amount Q is larger than 300 [liter / min].

  As described above, according to the pump device according to the present embodiment, when the load of the prime mover 20 that drives the pump unit 10 is increased, the rotation speed is decreased, and when the load is decreased, the rotation speed is increased. The rotational speed of the prime mover 20 is controlled so that does not exceed a predetermined upper limit. Therefore, as shown in the graph of FIG. 10, the performance is improved over a wide operating range from the low pressure / large flow rate operation range to the high pressure / small flow rate operation range, compared to the conventional method of keeping the rotation speed of the prime mover constant. it can.

  Further, according to the pump device according to the present embodiment, in the self-priming operation mode at the time of starting the pump, since the rotational speed of the prime mover 20 is made higher than that in the normal operation mode, the substantial pump operation is started. Time can be shortened. Further, whether or not the self-priming operation has ended is determined based on the load of the prime mover 20 (throttle opening S), and when the end of the self-priming operation is determined, the mode automatically shifts to the normal operation mode. The pump operation can be started. Moreover, since the rotation of the prime mover 20 is stopped when the self-priming operation mode continues for a certain time, the excessive load on the prime mover 20 and the pump unit 10 due to the high rotational speed for the self-priming operation continues for a long time. It can be effectively prevented.

  In addition, this invention is not limited to embodiment mentioned above, Various modifications are included.

FIG. 11 is a flowchart for explaining a rotation speed adjusting operation in a pump device according to another embodiment of the present invention.
The flowchart shown in FIG. 11 is obtained by adding steps ST110 to ST120 between step ST105 and step ST125 in the flowchart shown in FIG.
In this case, the target rotational speed adjusting unit 52 receives an input of the pump start signal and sets the target rotational speed Rt to a high rotational speed (for example, 4000 rpm) for self-priming operation, so that the rotational speed slower than this is set. (For example, 3600 rpm) is set in the rotational speed control unit 51 as the initial target rotational speed Rt (ST110). Then, the target rotational speed adjustment unit 52 acquires the throttle opening S of the load detection unit 40 at this initial rotational speed (ST115), and determines whether the throttle opening S is smaller than a predetermined lower limit value (ST115). ST120). When the throttle opening S is smaller than the lower limit value, the target rotational speed adjustment unit 52 sets the target rotational speed Rt to a high rotational speed for self-priming operation (ST125).
As described above, according to the processing of the flowchart of FIG. 11, since the self-priming operation is confirmed at a relatively low rotational speed and then the rotational speed is changed to a high rotational speed, an excessive load is applied to the prime mover 20 and the pump unit 10. Can be effectively prevented.

  In the embodiment described above, the difference DR between the rotation speed Ra (FIG. 4) corresponding to the load detection value and the target rotation speed Rt in the normal operation mode in which the load detection value (throttle opening) is smaller than the upper limit value (80). Is larger than a predetermined threshold value, the rotational speed intermediate between the rotational speed Ra and the target rotational speed Rt is set as a new target rotational speed Rt (ST235, FIG. 6), but the present invention is limited to this. Not. That is, the new target rotational speed Rt is included in the range from the rotational speed Ra corresponding to the load detection value to the original target rotational speed Rt, and the difference DR from the rotational speed Ra is the original target rotational speed Rt. The rotation speed may be any lower speed than that of the rotation speed, and is not limited to an intermediate value between the rotation speed Ra and the target rotation speed Rt as described above.

  In embodiment mentioned above, although the case where the pump part 10 is a centrifugal pump is mentioned as an example, this invention is not limited to this. Various types of pumps other than centrifugal pumps may be used in the pump unit of the present invention.

  In the embodiment described above, a case where the prime mover 20 is an engine (reciprocating engine) is taken as an example, but the present invention is not limited to this. Various types of internal combustion engines may be used for the prime mover of the present invention. For example, an electric motor may be used as a power source other than the internal combustion engine.

  DESCRIPTION OF SYMBOLS 5 ... Frame, 10 ... Pump part, 11 ... Suction port, 12 ... Discharge port, 13 ... Spiral casing, 14 ... Impeller, 15 ... Water filling stopper, 20 ... Motor | power_engine, 21 ... Rotating shaft, 30 ... Rotation speed detection part, 40 ... Load detection unit, 50 ... Control unit, 51 ... Rotation speed control unit, 52 ... Target rotation speed adjustment

Claims (10)

A pump section;
A prime mover for driving the pump unit;
A rotational speed detector for detecting the rotational speed of the prime mover;
A rotation speed control unit that controls the rotation speed of the prime mover so that the rotation speed detected by the rotation speed detection unit approaches a target rotation speed;
A load detector for detecting a load of the prime mover;
When the load increases, the rotation speed decreases, and when the load decreases, the rotation speed increases, and a predetermined upper limit value of the load is set and approaches a predetermined relationship between the load and the rotation speed. Thus, the pump apparatus which has a target rotational speed adjustment part which adjusts the said target rotational speed according to the detected value of the said load in the said load detection part. The pump unit is a self-priming pump,
When the target rotational speed adjustment unit receives a signal instructing start of the pump unit, the target rotational speed control unit sets a target rotational speed for self-priming operation faster than the fastest rotational speed defined in the predetermined relationship. Set
The pump device according to claim 1. The target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and then compares the detected value of the load with a predetermined lower limit value. If the lower limit is exceeded, the adjustment of the target rotational speed according to the detected value of the load is performed.
The pump device according to claim 2. The target rotational speed adjustment unit sets the target rotational speed for the self-priming operation in the rotational speed control unit, and if the state where the detected load value is smaller than the lower limit value continues for a certain period of time, the prime mover Stop rotating,
The pump device according to claim 3. The target rotation speed adjustment unit, when receiving a signal instructing the start of the pump unit, sets a predetermined initial target rotation speed in the rotation speed control unit, and after the setting, the detected value of the load and the load Comparing with a lower limit value, if the detected value of the load is smaller than the lower limit value, the target rotational speed for the self-priming operation is set in the rotational speed control unit,
The pump device according to claim 3 or 4. The target rotational speed adjusting unit, when performing the adjustment of the target rotational speed according to the detected value of the load, a predetermined rotational speed corresponding to the detected value of the load in the predetermined relationship, and the rotational speed control A difference with the target rotational speed being set in the part, and if the calculated difference exceeds a predetermined threshold, it is included in a range from the predetermined rotational speed to the target rotational speed being set, And, a new target rotational speed that is smaller than the calculated difference is set in the rotational speed control unit.
The pump apparatus as described in any one of Claims 1 thru | or 5. The target rotational speed adjustment unit sets an intermediate rotational speed in a range from the predetermined rotational speed to the target rotational speed being set to the rotational speed control unit as the new target rotational speed.
The pump device according to claim 6. When the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, if the detected value of the load exceeds the upper limit value, the detected value of the load becomes the upper limit value. Reducing the target rotational speed until it becomes smaller,
The pump apparatus as described in any one of Claims 1 thru | or 7. The target rotation speed adjustment unit is configured such that the detected value of the load exceeds the upper limit value and the target rotation speed set in the rotation speed control unit is faster than the minimum rotation speed defined in the predetermined relationship. For example, if the minimum rotation speed is set in the rotation speed control unit as the target rotation speed and the detected value of the load exceeds the upper limit value even after the setting, the detected value of the load is more than the upper limit value. Decrease the target rotational speed by a predetermined change until it becomes smaller,
The pump device according to claim 8. When the target rotational speed adjustment unit performs the adjustment of the target rotational speed according to the detected value of the load, the target rotational speed set in the rotational speed control unit is the lowest specified in the predetermined relationship. If the load detection value is lower than the rotation speed, the load detection value is smaller than the upper limit value, and the difference between the load detection value and the upper limit value exceeds a predetermined threshold, the load detection value and the upper limit Increasing the target rotational speed until the difference from the value is smaller than the threshold value,
The pump apparatus as described in any one of Claims 1 thru | or 9.