JP2009510299A - Pump control system - Google Patents

Abstract

  The present invention relates to a pump comprising variable frequency drive means and a method of operating such a pump. The method of the present invention for operating the pump (1) includes the step of obtaining the value of the operating parameter of the pump (1) indicating the pump state, and the value of the operating parameter from the variable frequency driving means (2) to the control device ( 11) communicating to the variable frequency driving means (2) from the control device (11) based on the achievement of the predetermined state, the step of communicating to 11), the step of determining whether or not the predetermined state is satisfied And a step of performing. Furthermore, a computer program product that can be loaded into the memory of a digital computer device, comprising a software code part for performing the method of the invention, a pump (1), a pump system, and a pump A control device (11) for is described.

Description

  The present invention relates generally to the field of pumps, and more particularly, the invention relates to pumps with variable frequency drive means. Furthermore, the invention also relates to a method for operating such a pump.

  Pumps with variable frequency drive means, such as sewage pumps, drainage and dehydration pumps, and submersible pumps, are fluids in mining applications such as mining shafts, wells, construction sites, or other applications. Is commonly used for pumping. Typically, submersible pumps are submerged in whole or in part for an extended period of time, both when they are operating and when they are off.

  In general, a problem that pumps and especially submersible pumps often encounter is the so-called snowing operation, which means that the pump draws some liquid and some air. This is due to the liquid level dropping below the required level of the pump and starting to draw some air into the pump. From this moment the pump is no longer successful and uses energy unnecessarily. The water silt remains in the mining shaft or well and the particles will settle and begin to deposit in the pump's hydrodynamics. As long as the pump is in this snowing condition, these particles remain in hydrodynamics and cause extra wear on the impeller, suction cover, seals, etc. This inefficient pump delivery contributes significantly to increasing the overall operating cost of the pump. In addition, this snowing action may damage the pump motor due to overheating. In certain applications, to overcome this snowing problem, a sensor such as a level switch is used to sense the fluid level in the well. However, these level sensors may be blocked or subject to level shifts, for example, due to collisions with objects such as tree branches in the fluid, and thus In case you supply the wrong signal.

  U.S. Pat. 6481973 presents a pump system that addresses some of the aforementioned problems. Even though this pump system includes variable frequency drive means, it uses another control method to detect whether the liquid level has dropped below a preset level as a complement to the level switch. More precisely, the pump system detects whether there is a sudden increase in motor speed or a sudden drop in motor torque. The operation of the motor is monitored by a sensor connected to an AC output link extending from the variable frequency drive means to the motor. However, this pump system has major drawbacks. If the motor speed increases slowly, the system recognizes the change as an indication of the pump's dry running. In other cases, the pump system cannot detect whether the water level is high enough for pump operation at the start of the pump. This is because in this state there can be no sudden increase in motor speed or sudden drop in motor torque. Thereby, the pump will run for a significant amount of time until it is switched off due to overheating, and the pump will run the risk of serious damage.

  In many applications, as described above, the pump operates in a dynamic environment, so the pump should be able to operate efficiently with a large range of heads / pressures. The lift corresponds to the height, and the pump can use a given power to lift a given amount of liquid, for example water. See FIG. 3 where a typical pump curve is indicated by line 30. The degree of pump power utilization is reduced with low flow (Q). Thus, it would be advantageous to have a pump that can deliver at a higher (or increased) degree of pump power and at lower flow rates.

  Another problem that occurs frequently, especially when the pump has been off for a very long time, is intake and / or impeller clogging, which is settled at the intake and in the impeller. And mainly caused by particles in the fluid that make up the silt with a relatively thick or dense consistency. This then entails that a large starting torque of the pump motor is then required to start the rotation of the pump impeller. In many cases, a maximum starting torque is further required to initiate rotation, and the motor must be operated at maximum torque for a considerable period of time. This consumes a large amount of energy and also wears the pump impeller and motor. When the pump has been off for an extended period of time, even the maximum starting torque may not be sufficient, and in such a case the pump must be cleaned manually. In addition, the pump may also become clogged during operation, for example due to particles sucked into the impeller. Therefore, the reliability of a pump operated in such an environment is low.

  U.S. Pat. The aforementioned pump system according to 6481973 also addresses this problem. However, this method is incorrectly oriented to keep the motor running even if it is determined that the pump is clogged. More precisely, if an unacceptably high motor torque is detected for a given speed of the motor, the pump system will reduce the speed of the motor and simultaneously increase the level of acceptable motor torque. . Its purpose is to obtain a stronger pump that can overcome the strength of solids, but a stronger motor combined with hard dirt will damage the impeller, impeller seat, pump housing, etc. There is.

  Another known problem with pumps with conventional variable frequency drive means is that the variable frequency drive means is usually installed in a dry place above the ground away from the pump. More precisely, this requires a long power cable leading from the variable frequency drive means to the pump motor, which for variable frequency drive means poses severe problems with electromagnetic interference. The aforementioned U.S. Pat. In 6481973, variable frequency drive means are mounted in the pump casing, more precisely on a plate connected to the motor. However, the operation of the variable frequency drive means is in this case adversely affected by the heat released from the motor, which can lead to incorrect operation of the variable frequency drive means.

Accordingly, there is a need for improved pumps and improved control methods that efficiently control such pumps with respect to energy consumption and pump durability.
Accordingly, it is an object of the present invention to provide an improved pump, a pump system including such a pump, a computer program, a controller for such a pump, and a head for changing such a pump and pump system. It is to provide a method for controlling the pump capacity in an efficient manner.

  Another object of the present invention is to provide an improved pump, a pump system including such a pump, a computer program, a controller for such a pump, and an efficient use of such a pump and pump system for energy consumption. It is to provide a method of controlling by a simple method.

  Another object of the present invention is to provide an improved pump, a pump system including such a pump, a computer program, a controller for such a pump, and such a pump and pump system with regard to pump durability. The object is to provide a method of controlling in an efficient manner.

  It is a further object of the present invention to provide improved pumps, pump systems including such pumps, computer programs, controllers for such pumps, and pumps and pump systems to reduce pump wear and It is to provide a method of controlling to extend the pump life.

  Yet another object of the present invention is to provide an improved pump, a pump system including such a pump, a computer program, a controller for such a pump, and a pump and pump system that are environmentally efficient. It is to provide a method of controlling by a technique.

  Another object of the present invention is to provide an improved pump, a pump system including such a pump, a computer program, a controller for such a pump, and the reliability of starting such a pump and pump system. Another object of the present invention is to provide a method for controlling the reliability during operation in an efficient manner.

  These and other objects are in accordance with the present invention an improved pump, such a pump, a computer program, and the features having the characteristics defined in the so-called independent claims in the appended claims. This is accomplished by providing a method for controlling such a pump and pump system.

In the context of the present invention, the term “pump speed” is defined as the number of revolutions of the pump per unit time.
According to a first aspect of the present invention, there is provided a method of operating a pump comprising a motor and variable frequency driving means, wherein the variable frequency driving means is connected to a feeder cable of the motor and the pump, thereby the motor. The variable frequency drive means comprises a rectifier, an inverter, and a DC link extending between the rectifier and the inverter, and the pump is operable to the controller. Connected, the method is provided. This method
Obtaining a value of an operating parameter of the pump indicating a pump state by a detecting means configured in the variable frequency driving means and operably connected to the DC link;
Communicating the value of the operating parameter from the variable frequency drive means to the controller;
Determining by the controller whether a predetermined condition is satisfied based on the acquired value of the operating parameter;
Communicating a command from the controller to the variable frequency drive means based on the achievement of the predetermined state to control the operation of the motor according to the pump state.

According to a second aspect of the present invention, there is provided a pump configured to operate according to the above method.
According to a third aspect of the present invention, there is provided a computer program product that can be loaded into a memory of a digital computer device when the computer program product is operated on the digital computer device. A computer program product is provided that includes software code portions for performing a method according to the above aspects.

According to a fourth aspect of the present invention there is provided a pump system comprising a pump according to the second aspect of the present invention.
According to a further aspect of the present invention, a pump control device according to the second aspect of the present invention is provided.

  Therefore, the present invention obtains from the variable frequency drive means the value of the pump operating parameter indicating the pump state substantially continuously, and the operating parameter is measured easily, inexpensively and at the same time with high accuracy; And based on the idea that the variable frequency drive means is controlled based on the obtained value of the operating parameter, where the rotation of the motor is adjusted according to the pump condition. Thereby, the pump is operated in an efficient manner with respect to output capacity at varying flow rates, energy consumption and pump pump durability. In addition, wear of pump parts such as impellers and seals is reduced, so that pump life can be extended. No external sensor is required because all information required for control of the pump, pump motor and variable frequency drive means is obtained from the variable frequency drive means.

  In accordance with a preferred embodiment of the present invention, the operating parameter may be the DC link voltage of the variable frequency drive means, the DC link current of the variable frequency drive means, the speed of the motor, or the like. These operating parameters may determine motor power, motor torque, or other suitable amount.

  In accordance with a preferred embodiment of the present invention, a pump dry running event is determined based on the obtained value of the operating parameter, e.g., the power of the motor at different motor speeds is compared to a predetermined reference value. The If it is determined that the power of the motor is below a predetermined reference level, the pump motor operation is stopped during a period having a predetermined length. In addition, the motor is started again when the predetermined period has elapsed and the same check is performed once again until the predetermined condition is met. Thus, as mentioned above, the problem of snowing operation which causes unnecessary wear of the pump, in particular the impeller and which leads to unnecessary energy consumption is addressed, so that variable frequency drive means in terms of energy consumption and durability. An efficient method of operating a pump comprising In addition, pump life can extend pump life as a result of significantly reduced wear of pump components such as impellers, seals and suction covers.

  In an alternative embodiment of the invention, the power of the motor is maintained at a substantially constant level. The acquired operating parameter is compared with a predetermined reference level of the operating parameter, and if the operating parameter value is lower than the predetermined reference level, the motor speed required to acquire the predetermined power level is calculated. And the pump is operated at its calculated speed. The calculated speed is compared to the preset maximum allowable speed of the pump, and if the calculated speed is higher than the preset maximum allowable speed of the pump, the pump is preferably operated at the preset maximum allowable speed. Thus, the problem of maintaining a high degree of pump power utilization over a large flow range is addressed. As shown by line 32 in FIG. 3, the lift / pressure can be increased by 20% to 30% by the method according to the second aspect described above. Thus, by increasing the speed of the motor, the pump will reach a higher lift at a lower flow rate than a conventional pump. Thus, an efficient way of operating a pump with variable frequency drive means is obtained with respect to pump capacity at varying heads.

  According to another embodiment of the present invention, detection of whether the pump is clogged is performed, and if it is detected that the pump is clogged, the pump is over a period of time having a predetermined length. Operated in the opposite direction at a predetermined speed. The pump is then stopped and started in the normal direction. Further, the steps of operating the pump impeller in the reverse direction, then stopping it, and further changing the direction of operation are repeated until it is detected that the clogging condition has stopped. Accordingly, clogging or jamming of the intake and / or pumping house caused by particles that settle at the intake and on the impeller and produce a silt having a relatively thick or hard consistency. The problem is dealt with. As a result of the pump being repeatedly operated in the reverse direction and again in the forward direction, clogging can be effectively removed. Thereby, the starting reliability is increased. Moreover, this embodiment provides an efficient way of operating a pump with variable frequency drive means, in terms of energy consumption and durability, in particular because the wear of the pump impeller is reduced. Furthermore, since the clogged state is efficiently removed, the energy consumption of the pump can be reduced.

  As will be appreciated by those skilled in the art, the method according to the present invention, as well as preferred embodiments of the method, is preferably a computer program or computer readable medium, preferably in the contents of a controller, or a pump or pump pump. Suitable for implementation or execution within the processing means of the system.

  The features that characterize the present invention both in terms of structure and method of operation, together with further objects and advantages of the present invention, will be better understood from the following description read in conjunction with the accompanying drawings. It will be expressly understood that the drawings are for illustrative purposes and are not intended as a definition of the limits of the invention. These and other objects and advantages provided by the present invention will become more fully apparent as the following description is read in conjunction with the accompanying drawings.

  The above and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments, which are merely illustrated in connection with the accompanying drawings.

In the following, preferred embodiments of the method of operating the pump and pump system will be disclosed.
Referring to FIG. 1, a first embodiment according to the present invention is shown. For illustrative purposes, the embodiments of the invention described below are utilized in current submersible pumps with variable frequency drive means. However, as those skilled in the art will readily recognize, the present invention can also be utilized with other types of pumps such as sewage pumps, drainage pumps, dewatering pumps, and the like.

  The submersible pump 1 in FIG. 1 is connected to a power supply (not shown) for supplying, for example, a single-phase voltage or a three-phase voltage via a connection cable 3, preferably a variable frequency drive means (VFD unit). Is provided. Unlike a prior art pump with a VFD unit, which is simply designed to receive a power supply in the range of approximately 200V to approximately 250V, the pump 1 according to the present invention is from approximately 90V A supply power in the range of approximately 250V can be received. Thereby, the pump 1 of the present invention can be used in both a country / region having a standard supply power of approximately 110V and a country / region having a standard supply power of approximately 230V. Moreover, the prior art pumps are designed to be supplied with electricity having a frequency of 50 Hz or 60 Hz, which is known as standard for different countries and / or different regions of the country. However, the pump of the present invention is designed to be used in many different countries. That is, the input frequency is in the range of at least 50-60 Hz, but in practice the pump of the present invention can successfully cope with any available frequency. Thus, a given pump can be used connected to many different power trunks. That is, a given pump is a globally usable pump that can be put into operation immediately.

  The VFD unit 2 includes an electromagnetic interference filter 4 (EMI filter) disposed in the connection cable 3 to filter out electromagnetic interference at the input. The connection cable 3 is connected to the feeder cable of the pump 1. The EMI filter 4 is connected to a rectifier 5, which is then connected to a transducer or inverter 7 via a DC link 10 that includes a capacitor 6. The inverter 7 converts the DC current into a three-phase current, and the three-phase current is supplied to the pump motor 9 via the connection portion 8. The functions, components and parts of the VFD unit 2 are well known to those skilled in the art and will therefore not be described in further detail here.

  The VFD unit 2 is mounted to be thermally shielded from the pump motor 9 and at the same time mounted in a configuration that can conduct heat with the fluid delivered by the pump so that the temperature of the VFD unit 2 is lowered to a low level during operation. It is important that it is kept and that it eliminates the cause of the error.

  The controller 11 is operably connected to the pump 1 and configured to communicate with the VFD unit 2 via a connection bus (not shown) and controls or drives the pump 1, for example, more or more Increase or decrease the speed of the pump motor 9 to deliver a small amount of liquid, for example water. Further, the VFD unit 2 includes a detecting means 16 that is operatively connected to the DC link 10 and configured to obtain a value of an operating parameter of the pump 1 indicating a pump state. Yes.

  The VFD unit 2 is configured to communicate the values of the operating parameters to the control device 11. It should be noted that the above operating parameters according to preferred embodiments of the present invention may be DC link voltage, DC link current, motor speed, or the like. These operating parameters determine the power of the pump 1 or motor 9, the torque of the motor 9, or other suitable amount. The control device 11 determines whether or not the predetermined state is satisfied based on the acquired value of the operation parameter, and controls the operation of the motor 9 according to the pump state. An instruction is configured to communicate to the VFD unit 2 based on the achievement.

  Next, the control device 11 is controlled by the processing means 12 including the storage means 13. The storage means 13 may include non-volatile memory such as random access memory (RAM) and / or read only memory (ROM). In this embodiment, the storage means 13 comprises a computer program 14 having instructions for causing a computer or microprocessor such as the processing means 12 to perform the method steps according to the present invention. As will be appreciated by those skilled in the art, the storage means 13 may include various types of physical devices for temporary and / or permanent data storage, including solid state, magnetic, optical, and combinations thereof. May be included. For example, the storage means 13 can be implemented using one or more physical devices such as DRAM, PROMS, EPROMS, EEPOMS, flash memory, and the like.

  With reference now to FIG. 2, an alternative embodiment of the present invention will be described. In this embodiment, the controller 11 is configured to communicate with the operator unit 22 via an interface unit (not shown). The operator unit 22 includes input means in the form of a keyboard 24 that allow the operator to enter control commands, for example, and information related to the operation of the pump, eg time history of operating parameters or pump status information. Display means or a screen 26. In one embodiment, operator unit 22 is a personal computer. The communication link between the pump 1 and the operator unit 22 can be a radio link or a hard wired link. Furthermore, the operator unit 22 can then be connected to a communication network such as the Internet. The operator unit 22 allows the operator to monitor the operation of the pump as well as various operating parameters associated with that operation via the display 26. According to another embodiment, the display 26 is a touch-sensitive screen, and in this case, a number of soft keys are arranged on the screen to provide various commands with various interfaces provided on the display 26. Can do. Further, the operator unit 22 may be provided with a storage means (not shown). The storage means may then include non-volatile memory such as random access memory (RAM) and / or read only memory (ROM). As will be appreciated by those skilled in the art, the storage means may include various types of temporary physical devices and / or permanent data storage, including solid state, magnetic, optical and combinations thereof. . For example, the storage means may be implemented using one or more physical devices such as DRAM, PROMS, EPROMS, EEPOMS, flash memory, and the like.

  Pump 1 operating data such as operating time, number of starts, energy consumption and warning data, and operating parameters such as service records can be obtained and stored in a logging file in storage means 13. it can. The logging file can be provided to the operator by the operator unit 22. Furthermore, the logging file can be downloaded to the operator unit 22 for storage, for example.

  Of course, there are many possible designs for the control device 11. For example, the control device 11 can be realized, inter alia, by a processor including programmable instructions for performing the method according to the invention. According to another embodiment, the controller 11 is implemented in the form of a microchip or similar data carrier with software adapted to perform the functions described above and below. Furthermore, an alternative embodiment of the present invention is shown in FIGS. Similar or similar components and / or devices in FIGS. 1, 2, and 7-9 are indicated with the same reference numerals. In FIG. 7, the control device 11 may be enclosed in a hermetically sealed housing, but the control device 11 is located on the outer surface of the pump housing. The control device 11 can be mounted or fixed to the housing in a number of ways. For example, the control device 11 can be fixed by screws. In FIG. 8, the control device 11 is in the form of a plug-in unit adapted to be inserted into the control device receiving recess 15. In FIG. 9, the control device 11 is disposed on the control panel 22.

  Referring now to FIG. 4, the general principle of a method for operating a pump according to the first aspect of the present invention is shown. This first aspect of the method according to the present invention addresses the snowing problem or the dry running problem. These problems inevitably lead to increased wear of pump parts such as impellers and seals, causing the pump motor to overheat and also consume unnecessary energy. In addition, the pump motor is designed to deliver optimal performance when delivering and operating on liquids, thereby damaging the pump motor by prolonging the dry running operation. Accordingly, a first aspect of the invention relates to energy consumption, pump life and durability as described with reference to any one of FIGS. An efficient way of operating a pump 1 comprising a unit 2 is provided.

  Initially, at step 40, the operation of the pump is started, i.e. the pump is started. Steps 42 and 44 then determine whether the predetermined condition has been met. For example, in step 42, the pump is operated for a predetermined period at a first speed level and for a predetermined period at a second speed level. The first speed level and the second speed level are preferably low speed levels. For each speed level, the power of the motor 9 is determined, and then, at step 44, the relationship between the speed of the motor 9 and the power of the motor uses the two speed levels and the resulting power from each of them. Thus, it is checked whether or not it is approximately a cube function (when the motor power is proportional to the cube of the motor speed). If the relationship is a cube function, the pump can operate in normal operation, and if the relationship is not a cube function, it is an indication that the pump 1 is delivering air, and It is determined that the liquid level is too low and the pump cannot operate at the desired speed level. This determination is executed by the processing means 12 in the control device 11, for example. It is pointed out that the relationship between the velocity level and the resulting power does not necessarily have to be the third power, but other exponential functions may be appropriate for other mixtures of fluids, ie liquids and gases. Should be kept.

  If it is determined at step 44 that the liquid level is not sufficient, the algorithm proceeds to step 46 where the controller 11 sends a command to the VFD unit 2 to operate the pump over a predetermined period of time, for example , Number of minutes, maybe pause / pause for about 2 minutes. When this period has elapsed, the algorithm returns to step 42.

  On the other hand, if it is determined at step 44 that the liquid level is sufficient, the algorithm proceeds to step 48 where the speed of pump 1 is increased to the desired speed. Accordingly, the pump 1 is now operated in a normal manner.

  In order to avoid snowing movements, it is checked substantially continuously that the pump 1 is not delivering air during operation. Thus, in step 50, whether the liquid level is still sufficient, i.e. whether the pump 1 is partially or primarily sucking air or whether the pump 1 is delivering liquid is a second predetermined. Is checked by determining whether the condition of is satisfied. This is performed on a substantially continuous basis. In order to perform this check, an appropriate operating parameter value is obtained by the detection means 16 of the VFD unit 2 and the value is communicated to the control device 11. For example, a DC link voltage, a DC link current, or the like can be used directly or can be used to determine, for example, the torque of the motor 9, or preferably the power of the motor 9. A sudden drop in the power of the motor 9 during operation indicates that the pump 1 is delivering air instead of liquid.

  For example, the second state is a comparison of the power of the motor 9 with, for example, a predetermined reference level that can be stored in the storage means 13, and if the power of the motor 9 is lower than the predetermined reference level, the liquid level Is determined to be too low. This predetermined level is preferably about 70% of the maximum power of the motor 9 with respect to the current speed of the motor 9. Alternatively, a step comparable to step 42 may be performed periodically between step 48 and step 50 to determine if liquid is present at the inlet of pump 1.

  If it is determined that the liquid level at the inlet of the pump 1 is sufficient, ie the power of the motor 9 is higher than a predetermined level, the algorithm proceeds to step 48. On the other hand, if it is determined that the liquid level at the inlet of the pump 1 is too low, i.e. the power of the motor 9 is lower than the predetermined level, the algorithm instead proceeds to step 52 where the operation of the pump 1 Is stopped. Subsequently, the algorithm proceeds to step 46 where the operation of the pump 1 continues to be stopped for a predetermined period. When this pause period has elapsed, the algorithm proceeds to step 42.

  Referring now to FIG. 5, the general principle of a method for operating a pump according to the second aspect of the present invention will be described. This second aspect of the method according to the invention addresses the problem of maintaining pump power at a substantially constant level over a large range of flows. As shown by line 32 in FIG. 3, the lift / pressure can be increased by 20% to 30% by the method according to the second aspect. The pump power is maintained at a substantially constant level with varying heads by adjusting the speed of the motor. Due to the pump being operated more efficiently at lower flow, a smaller pump can be used to deliver a given amount of liquid and pump wear can also be reduced. it can. The pump of the present invention is a general purpose pump designed to be used in many different applications with varying demands. A high pump capacity is achieved for a given pump that changes the head by adjusting the speed of the motor. Accordingly, a second aspect of the present invention is a pump comprising a VFD unit 2 as described with reference to FIGS. 1, 2 and any of FIGS. 7-9 in terms of energy consumption and durability. Provides an efficient way to operate.

  First, in step 60, the operation of the pump 1 is started, i.e. the pump 1 is started. Then, at step 62, the pump 1 is operated at the desired speed level. The operating parameters of the pump are monitored substantially continuously, and values corresponding to the operating parameters are obtained by the detection means 16 of the VFD unit 2 and the values are communicated to the control device 11. For example, DC link voltage, DC link current, or the like can be used directly or used to determine, for example, the torque of the motor 9 or preferably the power of the motor 9. In the control device 11, the power of the motor 9 is compared with a predetermined reference level, for example the rated power of the motor 9, for example in step 64, which is stored in the storage means 13 in the processing means 12, for example. If it is determined at step 64 that the power level of the motor 9 is higher than the predetermined reference level, the algorithm returns to step 62 and the operation of the pump 1 is maintained at the desired speed level as described above. On the other hand, if it is determined that the power level of the motor 9 is lower than the predetermined reference level, the algorithm proceeds to step 66 where the speed required to reach the predetermined power level of the motor 9 is Calculated by the processing means 12.

  Thereafter, at step 68, the calculated speed is compared to a preset maximum speed. If it is found that the calculated speed is higher than the preset maximum speed, the algorithm proceeds to step 70 where the controller 11 communicates a command to the VFD unit 2 to operate the motor 9 at the preset maximum speed. And the algorithm returns to step 64. If it is found that the calculated speed is lower than the preset maximum speed, the algorithm proceeds to step 72 and the controller 11 communicates a command to the VFD unit 2 to operate the motor 9 at the calculated speed. . The algorithm then proceeds to step 64 where the processing procedure continues. By maintaining the motor power at a substantially constant level, the lift / pressure can be increased with low flow, as shown by line 32 in FIG.

  Referring now to FIG. 6, the general principle of a method for operating a pump according to the third aspect of the present invention will be described. This third aspect of the method according to the invention addresses the problem of clogging or jamming of the intake of the pump 1 and / or impeller, which settles at the intake and is relatively thick or dense. Caused by particles in the fluid that make up silt with consistency. Therefore, a large starting torque of the pump motor is required to start the rotation of the pump impeller. This consumes a large amount of energy and also wears the pump impeller and motor. When the pump has been in the off state for a long time, even the maximum starting torque is not sufficient, and in such a case the pump must be manually cleaned and subsequently operated in such an environment The starting reliability of the pump will be low. Accordingly, the third aspect of the present invention, as described with respect to energy consumption, durability and start-up reliability, will be described with reference to FIGS. 1, 2 and any of FIGS. 7-9. An efficient method of operating a pump comprising a VFD unit 2 is provided.

  First, in step 80, the operation of the pump 1 is started, i.e. the pump 1 is started. Then, at step 82, the pump 1 is operated at the desired speed level. Thereafter, at step 84, a check is performed to see if the pump has clogged / jammed. As an example, this can be performed in the following two ways. One method is to measure the operating parameter of the pump and compare it with, for example, a predetermined reference level to determine the power of the motor 9 and to determine it at a predetermined reference level of the power of the motor 9, for example, the motor. This is a method for comparison with the rated power of 9. If the measured power of the motor is higher than this predetermined reference level, it is an indication of a clog / jam condition. The second method is a method of monitoring the warning function of the variable frequency driving means 2, and a warning indicating a DC link overcurrent is used as an indication of a clog / jam condition.

  If at step 84 it is determined that the pump 1 is not clogged, the algorithm returns to step 82 where the operation of the pump 1 is maintained. On the other hand, if it is determined that the pump 1 is clogged, the algorithm proceeds to step 86 where the controller 11 communicates a command to the VFD unit 2 to set the impeller at a first speed. Drive in the reverse direction during the period. After a predetermined period, the pump 1 is stopped and then operated again in the forward direction. Such a cycle preferably lasts approximately 1-10 seconds. Then, in step 88, it is checked whether the clogging condition has stopped as performed in step 84 above. If the clogging state has not stopped, the processing procedure returns to step 86. This cycle is repeated until the clogging condition is removed. If the clogging condition stops, the algorithm returns to step 82.

  In order to prevent clogging during normal operation of the pump 1, the following processing procedure is periodically executed. The processing procedure is to operate the pump 1 in a reverse direction at a predetermined speed for a period having a predetermined length, then stop the pump 1 after the above period, and further stop the pump 1 in its normal direction of rotation. It is a procedure to operate. Thereby, the operational reliability of the pump can be further improved.

  Reference is now made to FIG. The lines indicated by reference numerals 30 and 32 are examples of liquid flow rate and head for a given pump 1, which is supplied with a three-phase voltage having a frequency of 60 Hz from the VFD unit 2. . 60 Hz is the standard frequency on some national power trunks, but with VFD unit 2 this level can be increased considerably, for example up to 150 Hz, and by doing so the above line 30, 32 are more or less offset upward in the chart of FIG. 3, and certain pumps can be used for highly fluctuating applications and conditions.

While specific embodiments of the invention have been described and described for purposes of illustration and illustration herein, the specific embodiments shown and described may be varied in many ways without departing from the scope of the invention. It will be appreciated by those skilled in the art that alternative embodiments and / or equivalent embodiments may be substituted. Those skilled in the art will readily appreciate that the present invention may be implemented in a wide variety of embodiments, including hardware and software implementations, or combinations thereof. As an example, many of the functions described above can be obtained and performed by suitable software on a microchip or similar data carrier. This application is intended to cover any adaptations or variations of the preferred embodiments described herein. Therefore, the present invention is defined by the terms of the appended claims and equivalents thereof.

FIG. 1 schematically shows an embodiment of a pump according to the invention. FIG. 2 schematically illustrates one embodiment of a pump system according to the present invention. FIG. 3 shows the pump curves for a conventional pump and a pump operated according to the present invention. FIG. 4 illustrates the principle of the method of one embodiment according to the present invention. FIG. 5 illustrates the principle of another embodiment method according to the present invention. FIG. 6 illustrates the principle of the method of yet another embodiment according to the present invention. FIG. 7 schematically shows another embodiment of a pump according to the invention and a control device for such a pump. FIG. 8 schematically shows a further embodiment of a pump according to the invention and a control device for such a pump. FIG. 9 schematically illustrates yet another embodiment of a pump and pump system according to the present invention.

Claims (31)

A method of operating a pump (1) comprising a motor (9) and a variable frequency drive means (2), wherein the variable frequency drive means (2) is a feeder of the motor (9) and the pump (1). The operation of the motor (9) is controlled by being connected to a cable, and the variable frequency driving means (2) includes a rectifier (5), an inverter (7), and the rectifier (5) and an inverter. In the method, comprising a DC link (10) extending between (7) and further wherein the pump (1) is operatively connected to a controller (11)
The value of the operating parameter of the pump (1) that indicates the pump status by the detecting means (16) that is configured as part of the variable frequency driving means (2) and is operatively connected to the DC link (10) Step to get the
Communicating the value of the operating parameter from the variable frequency drive means (2) to the controller (11);
Determining (44, 64, 84) by the control device (11) whether a predetermined state is satisfied based on the obtained value of the operating parameter;
Communicating the command from the controller (11) to the variable frequency drive means (2) based on the achievement of the predetermined state to control the motor (9) according to the pump state. Feature method.   The step of obtaining the value of the operating parameter of the pump (1) comprises the following operating parameters: DC link voltage level, DC link current level, torque of the motor (9) and power of the motor (9). 2. A method according to claim 1, comprising the step of obtaining at least one of the values.   The method according to claim 1 or 2, further comprising the step of detecting (44, 64, 84) a certain condition by using the at least one operating parameter.   The method according to claim 3, wherein the pump condition is related to the presence of liquid at the inlet of the pump (1). Said step of determining whether a predetermined condition is satisfied,
Operating the pump (1) at a first speed level for a predetermined period;
Operating the pump (1) at a second speed level for a predetermined period of time;
Whether the power of the motor (9) is proportional to the cube of the speed of the motor (9) is acquired by the detection means (16) for each of the first speed level and the second speed level. The method of claim 4, further comprising the step of determining based on the value of the operating parameter. The communicated command from the control device (11) to the variable frequency drive means (2) is:
Operating the pump (1) at a desired speed level (48) if it is determined that the predetermined condition is satisfied, or the pump (1) if it is determined that the predetermined condition is not satisfied 6. The method according to claim 4, wherein the operation of 1) is stopped (46) for a predetermined period. When the pump (1) is operated at a desired speed level,
Checking the presence of liquid at the inlet of the pump (1) (50);
Obtaining a value of an operating parameter of the pump (1) by the detecting means (16);
Communicating the value of the operating parameter from the variable frequency drive means (2) to the controller (11);
Determining by the control device (11) based on the acquired value of an operating parameter whether a second predetermined state is satisfied;
Communicating an instruction from the controller (11) to the variable frequency drive means (2) based on the achievement of the second predetermined state to control the operation of the motor (9). The method of claim 6.   The method of claim 7, wherein the step of determining whether a second predetermined condition is satisfied comprises comparing the obtained value of an operating parameter to a predetermined reference level. The communicated command from the controller (11) to the variable frequency drive means (2) is:
Operating the pump (1) at a desired speed level (48) if it is determined that the second predetermined condition is satisfied, or determining that the second predetermined condition is not satisfied 9. A method as claimed in claim 7 or 8, characterized in that the operation of the pump (1) is stopped (52) for a predetermined period when it is done.   The method of claim 2, further comprising maintaining a value of the at least one operating parameter at a substantially constant level. Said step of determining whether a predetermined condition is satisfied,
Operating the pump (1) at a desired speed level (62);
Based on the power value of the motor (9) acquired by the detection means (16) with respect to the desired speed level, the power of the motor (9) is more than a predetermined reference level of the power of the motor (9). 11. The method of claim 10, comprising determining whether it is low. The communicated command from the controller (11) to the variable frequency drive means (2) is:
Operating the pump (1) at the desired speed level (62) if it is determined that the predetermined condition is not satisfied, or if it is determined that the predetermined condition is satisfied, Calculate (66) the speed of the motor (9) required to reach a predetermined reference level of power of the motor (9) and operate the pump (1) at the calculated speed The method according to claim 10 or 11, wherein When the pump (1) is operated at the calculated speed,
Comparing the calculated speed of the pump (1) with a preset maximum speed of the pump (1);
(70) operating the pump (1) at the calculated speed if the calculated speed is lower than the preset maximum speed;
The method of claim 12, further comprising the step of operating the pump (1) at the preset maximum speed if the calculated speed is higher than the preset maximum speed.   The method according to claim 3, wherein the pump condition relates to clogging of the pump (1). Said step of determining whether a predetermined condition is satisfied,
Operating the pump (1) at a desired speed level (82);
Based on the power value of the motor (9) acquired by the detection means (16) with respect to the desired speed level, the power of the motor (9) is more than a predetermined reference level of the power of the motor (9). 15. The method of claim 14, comprising determining whether it is high. The communicated command from the controller (11) to the variable frequency drive means (2) is:
If it is determined that the predetermined condition is not satisfied, the pump (1) is operated at the desired speed level (82), or the pump (1) is reversed at a predetermined speed for a predetermined period. Operating (86), and if it is determined that the predetermined condition is met, after the predetermined period of reverse operation, the pump (1) in the normal operating direction is at the desired speed level. 16. A method according to claim 14 or 15, wherein Repeating the step (88) of determining whether the power of the motor (9) is higher than a predetermined reference level of power of the motor (9);
The method of claim 16, further comprising repeating the steps according to claim 16. The following steps are performed at regular intervals during the operation of the pump (1):
Operating the pump (1) in a reverse direction at a predetermined speed for a predetermined period;
15. The method according to claim 14, wherein after said predetermined period of reverse operation, the pump (1) is operated at a desired speed level in its normal operating direction.   19. A computer program product (14) loadable into a memory (13) of a digital computer device, wherein the computer program product (14) is run on the digital computer device. A computer program product (14) comprising software code portions for performing the method according to any one of the preceding claims. A pump (1) comprising a motor (9) and variable frequency driving means (2), wherein the variable frequency driving means (2) is connected to a feeder cable of the motor (9) and the pump (1). The operation of the motor (9) is thereby controlled, and the variable frequency driving means (2) includes a rectifier (5), an inverter (7), and the rectifier (5) and the inverter (7). In the pump (1), comprising a DC link (10) extending between and wherein the pump (1) is operatively connected to a control device (11)
The detection means (16) is configured as a part of the variable frequency drive means (2),
The sensing means (16) is operatively connected to the DC link (10);
The detection means (16) is configured to obtain a value of an operating parameter of the pump (1) that indicates a pump state;
The variable frequency driving means (2) is configured to communicate the value of the operating parameter to the control device (11);
For the control device (11) to determine whether a predetermined state is satisfied based on the acquired value of the operating parameter and to control the operation of the motor (9) according to the pump state A pump configured to communicate a command to the variable frequency drive means (2) based on the achievement of the predetermined condition.   The controller (11) obtains at least one value of the following operating parameters: DC link voltage level, DC link current level, torque of the motor (9) and power of the motor (9). 21. A pump according to claim 20, adapted to The control device (11)
Operating the pump (1) at a first speed level for a predetermined period of time;
The detection means (16) determines whether the pump (1) is operated at a second speed level for a predetermined period and whether the power of the motor (9) is proportional to the cube of the speed of the motor (9). 23. The pump of claim 21, wherein the pump is configured to determine based on a value of at least one operating parameter obtained for each of the first speed level and the second speed level. The control device (11)
Operate the pump (1) at a desired speed level if it is determined that the predetermined condition is satisfied, or operate the pump (1) if it is determined that the predetermined condition is not satisfied 23. A pump according to claim 22 adapted to stop the for a predetermined period of time.   The pump of claim 21, wherein the controller (11) is adapted to maintain a value of the at least one operating parameter at a substantially constant level. The control device (11)
Operating said pump (1) at a desired speed level;
Based on the power value of the motor (9) acquired by the detection means (16) with respect to the desired speed level, the power of the motor (9) is more than a predetermined reference level of the power of the motor (9). 25. A pump according to claim 24 adapted to determine whether it is low. The control device (11)
When it is determined that the predetermined state is not satisfied, the pump (1) is operated at the desired speed level, or when it is determined that the predetermined state is satisfied, the motor (9) Adapted to calculate (66) the speed of the motor (9) required to reach a predetermined reference level of power and to operate the pump (1) at the calculated speed The pump according to claim 24 or 25. The control device (11)
Comparing (68) the calculated speed of the pump (1) with a preset maximum speed of the pump (1);
If the calculated speed is lower than the preset maximum speed, operate the pump (1) at the calculated speed (70), or the pump if the calculated speed is higher than the preset maximum speed Operate (1) at the preset maximum speed (72)
27. A pump according to claim 26, adapted to The control device (11)
Operating the pump (1) at a desired speed level (82);
Based on the power value of the motor (9) acquired by the detection means (16) with respect to the desired speed level, the power of the motor (9) is more than a predetermined reference level of the power of the motor (9). Determine if it is high (84)
24. A pump according to claim 21 adapted to be adapted. The control device (11)
If it is determined that the predetermined condition is not satisfied, the pump (1) is operated at a desired speed level (82), or the pump (1) is operated at a predetermined speed in a reverse direction for a predetermined period. (86) and if it is determined that the predetermined condition is satisfied, the pump (1) is operated in the normal operating direction at the desired speed level after the predetermined period of reverse operation. 29. A pump according to claim 28 adapted to The control device (11) at regular intervals during the operation of the pump (1),
Operating the pump (1) in a reverse direction at a predetermined speed for a predetermined period;
A pump according to claim 21, adapted to operate the pump (1) in the normal operating direction at the desired speed level after the predetermined period of reverse operation. A pump station comprising a pump (1) according to any one of claims 20 to 30, comprising
An operator device (22) comprising input means (24) and display means (26);
A pump station adapted to present information related to the operation of the pump (1).

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