EA011044B1 - Control system for a pump - Google Patents

Abstract

The present invention relates to pumps comprising variable frequency drive means and methods for operating such pumps. The inventive method for operating a pump (1) comprises the steps of, obtaining values of operating parameters of the pump (1) indicating pump conditions, communicating said values of operating parameters from variable frequency drive means (2) to a control device (11), determining if a predetermined condition is full-filled, communicating instructions from the control device (11) to the variable frequency drive means (2), based on the fulfilment of said predetermined condition. Furthermore, a computer program product loadable into a memory of a digital computer device, including software code portions for performing the inventive method, a pump (1) , a pump system and a control device (11) for a pump are described.

Description

Technical field

The present invention relates to pumps, in particular to pumps comprising a variable frequency drive means. In addition, the present invention also relates to a method of operating such pumps.

State of the art

Pumps containing variable speed drives, such as sewage pumps, drainage pumps and sump pumps, as well as submersible pumps, are typically used to pump liquids in the mining industry, in applications such as mines, wells (wells), on construction sites, or in other applications. Typically, submersible pumps are immersed, in whole or in part, for extended periods of time both in operation mode and in idle mode.

With pumps in general and with submersible pumps, in particular, a problem often arises, which is called the ratchet of the pump, namely that the pump draws in partially liquid and partially air. This is due to the fact that the liquid level falls below the required level, and, as a result, the pump partially sucks in air. From this moment on, the pump loses productivity and unnecessarily wastes energy. Silt usually remains in the shaft or well, and its particles penetrate and accumulate in the hydraulic system of the pump. When the pump is in a ratchet state, these particles remain in the hydraulic system and lead to additional wear of the impeller, the cover of the suction channel, seals, etc. Work in such an inefficient mode significantly affects the increase in the total operating costs of the pump. In addition, snoring can damage the pump motor due to overheating. Certain applications use sensors, such as level switches, to detect the level of fluid in a well to eliminate snoring problems. However, these level switches may, for example, become blocked or undergo level drift due to collisions with objects in the fluid, such as tree branches, and in such cases they give an erroneous signal.

In the patent I8 6481973 disclosed a pumping system, which is aimed at solving part of the above problems. Despite the fact that this pump system contains a variable frequency drive means, it uses a different control method to detect a drop in the liquid level below a preset level, in addition to a level switch. In particular, this pumping system determines whether there has been a sudden increase in engine speed or a sudden drop in torque. Monitoring of engine operation is performed by a sensor connected to an alternating current output line passing from a variable frequency drive means to the engine. However, this pumping system has serious drawbacks. In cases where the increase in engine speed is slow, the system may not recognize the change as an indication of dry engine running. In another case, this pumping system will not be able to detect whether the water level is sufficient for the pump to operate when the pump starts, since in this state there cannot be a sudden increase in engine speed or a sudden drop in torque.

Therefore, in this case, the pump will run for a considerable time until it shuts off due to overheating, and, in addition, the pump will run with a greater risk of serious damage.

In many applications, such as the aforementioned applications, the pump operates in dynamically changing conditions, and accordingly, the pump must operate efficiently over a wide head / pressure range. The pump head corresponds to the height by which the pump can lift a given amount of liquid, such as water, using a given power; a typical pump head diagram is shown by line 30 in FIG. 3. The degree of use of pump power can be reduced at low flow rates (O). So, it is advisable to obtain a pump capable of pumping with a high (or increased) degree of use of pump power even at low costs.

Another common problem, especially when the pump is idle for a sufficiently long period, is the clogging of the inlet channel and / or the impeller, which is mainly caused by particles in the liquid that settle in the inlet channel and in the impeller and form sludge that is relatively thick or solid consistency. In turn, this entails the need for a large starting torque of the engine to start the rotation of the pump impeller. Often even the maximum starting torque is required to start rotation, and the engine must operate at maximum torque for a considerable period of time. In this case, a large amount of energy is consumed, and the impeller of the pump and the engine wear out. When the pump has been idle for a very long time, even the maximum starting torque may not be enough, and in such cases manual cleaning of the pump is required. In addition, the pump may also become clogged during operation, for example, by particles entering the impeller. Accordingly, the reliability of pumps operating under such conditions is low.

The aforementioned pumping system according to patent ϋδ 6481973 is also aimed at solving this problem. However, this method is erroneously aimed at keeping the engine running, even if it is determined that the pump is clogged. In particular, if at a given engine speed it is unacceptably detected

- 1 011044 high engine torque, the pump system will reduce engine speed and at the same time increase the level of available engine torque. The goal is to get a more powerful pump, which is able to overcome the resistance of a solid substance, however, the combination of a powerful engine and solid pollutant can lead to damage to the impeller, impeller support, pump housing, etc.

Another known problem with pumps containing conventional means of variable frequency drive, is that the latter is usually installed away from the pump, in a dry place located above the ground. In particular, this necessitates the use of a long supply cable extending from the variable frequency drive means to the pump motor, which for a conventional variable frequency drive means can lead to serious problems associated with electromagnetic interference. In the aforementioned I8 patent 6481973, a variable frequency drive means is installed inside the pump housing, more specifically, on a plate connected to the motor. However, the operation of the variable frequency drive means in this case is negatively affected by the heat radiated from the engine, which may lead to erroneous operation of the variable frequency drive means.

Accordingly, there is a need for an improved pump and an improved control method for controlling such a pump in an efficient manner with respect to power consumption and pump durability.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved pump, a pumping system including such a pump, a computer program, a control device for such a pump, and methods for controlling such a pump and pumping systems in an efficient manner with respect to pump capacity at variable pump head.

Another objective of the present invention is the creation of an improved pump, a pumping system including such a pump, a computer program, a control device for such a pump and methods for controlling such a pump and pumping systems in an efficient manner with respect to energy consumption.

Another objective of the present invention is to provide an improved pump, a pumping system including such a pump, a computer program, a control device for such a pump, and methods for controlling such a pump and pumping systems in an efficient manner with respect to pump durability.

Another objective of the present invention is to provide an improved pump, a pumping system including such a pump, a computer program, a control device for such a pump and a method for controlling such a pump and pumping systems in such a way as to reduce pump wear and extend the life of the pump.

Another objective of the present invention is to provide an improved pump, a pumping system including such a pump, a computer program, a control device for such a pump and a method for controlling such a pump and pumping systems in an efficient manner in relation to the environment.

Another objective of the present invention is to provide an improved pump, a pumping system including such a computer program pump, a control device for such a pump and a method for controlling such a pump and pumping systems in an efficient manner with respect to startup reliability as well as operational reliability.

These and other objectives are achieved according to the present invention by creating an improved pump, a pumping system including such a pump, a computer program and methods for controlling such a pump and pumping systems that have the distinguishing features defined in the independent claims. Preferred embodiments are defined in the dependent claims.

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 a variable frequency drive means, which is designed to control the operation of the motor when connected to a motor and a pump power cable and comprises a rectifier, an inverter and a direct current line passing between them, the pump being connected with a control device.

The specified method comprises the steps of obtaining the values of the operating parameters of the pump, indicating the status of the pump, by means of a sensor means, which is part of the means of the variable frequency drive and connected to the DC line, transmit the values of the operating parameters from the means of the variable frequency drive to the control device determine whether a given condition is satisfied based on the obtained values of the working steam

- 2 011044 meters by means of a control device and, based on the fulfillment of a predetermined condition, instructions are transmitted from the control device to the frequency-controlled drive means to control the operation of the motor in accordance with the mentioned pump conditions.

According to a second aspect of the present invention, there is provided a pump for operating in accordance with the aforementioned method.

According to a third aspect of the present invention, there is provided a computer program product loaded into a memory of a digital computer device, which includes pieces of program code for executing the method according to the first aspect of the present invention, when the computer program product is executed on a computer device.

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

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

Thus, the present invention is based on the idea of essentially continuously obtaining values of the pump operating parameters from a variable frequency drive means, these operating parameters indicating the state of the pump, and they are measured in an easy and inexpensive way and, at the same time, with high accuracy , and controlling the means of the variable frequency drive based on the obtained values of the operating parameters, and the operation of the motor is regulated according to the mentioned states of the pump. Thereby, the pump operates in an efficient manner with respect to productivity with variable costs, energy consumption and pump durability. Moreover, as wear on pump parts such as impellers and seals is reduced, pump life can be extended. Due to the fact that all the information necessary to control the pump, the pump motor and the variable frequency drive means is obtained from the variable frequency drive means, there is no need for external sensors.

According to a preferred embodiment of the present invention, the operating parameters may be: voltage in the direct current line of the variable frequency drive means, current of the direct current line of the variable frequency drive means, motor speed or the like. By means of these operating parameters, the motor torque can be determined engine torque or other suitable quantities.

In a preferred embodiment of the present invention, the dry running event is determined based on a comparison of the obtained values of the operating parameters, for example, engine power at various engine speeds, with a predetermined base value. If it is determined that the engine power is less than a predetermined base level, then the operation of the pump motor is suspended for a period of time from a certain duration. Moreover, the engine restarts when a certain period of time has elapsed, and the same test is performed again until a certain condition is satisfied. In this way, the ratchet problem is solved, which, as described above, leads to additional wear of the motor and, in particular, the impeller and can cause overheating of the pump motor and also leads to excessive energy consumption, and by this an efficient method of operation of a pump containing means can be obtained variable frequency means, regarding energy consumption and durability. In addition, the life of the pump can be extended by significantly reducing wear on engine parts such as the impeller, seals and inlet cover.

In an alternative embodiment of the present invention, engine power is maintained at a substantially constant level. The obtained value of the working parameter is compared with a given basic level of the working parameter; if the value of the operating parameter is less than a given base level, then the engine speed required to obtain a given power level is calculated; and the engine runs at calculated speed. Preferably, the calculated speed is compared with a predetermined maximum allowed speed of the pump, and if the calculated speed is higher than a predetermined maximum speed of the pump, then the pump operates at a predetermined maximum speed. Thus, the problem of maintaining a high degree of use of pump power in a wide range of costs is solved. As shown in FIG. 3 by line 32, by means of the method according to the second aspect, the head / pressure of the pump can be increased by 20-30%. Compared to a conventional pump, by increasing the speed of the motor, the pump will achieve a higher head at lower costs. Accordingly, an effective method of operating a pump comprising a variable frequency drive means has been obtained with respect to pump capacity at variable pressure.

According to another embodiment of the present invention, clogging of the pump is determined, and if it is detected that the pump is clogged, the pump starts in the opposite direction at a given speed for a period of time of a certain duration. Later, the pump stops and starts in the normal direction. Moreover, the step of rotating the pump impeller in the opposite direction, stopping it and changing the direction of rotation is repeated until it is determined that the clogging state has been removed. Thus, the problem of clogging or jamming of the inlet channel of the pump and / or pump housing, which can be caused by particles in the liquid that settle in

- 3 011044 inlet channel and on the impeller and form a sludge having a relatively thick or solid consistency. Due to the fact that the pump rotates back and forth again and again, clogging can be removed efficiently. This improves reliability during start-up. This embodiment provides an efficient method of operating a pump comprising a variable frequency drive means with respect to power consumption and durability, since wear, mainly of the pump impeller, is reduced. Moreover, since the clogging state can be eliminated in an efficient manner, the energy consumption of the pump can also be reduced.

It will be apparent to those skilled in the art that the method of the present invention, as well as its preferred embodiments, are suitable for implementation or implementation in the form of a computer program or computer-readable medium, preferably inside a control device or processing means for a pump or pump system.

Distinctive features of the invention, both in structure and method of operation, together with additional objectives and advantages will become apparent from the following description and the accompanying drawings. It should also be clearly understood that the drawings are intended to illustrate and describe, and not to define the boundaries of the present invention.

Brief Description of the 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 illustrative, with reference to the accompanying drawings, in which FIG. 1 is a diagram of an embodiment of a pump according to the invention;

FIG. 2 is a diagram of an embodiment of a pumping system according to the present invention;

FIG. 3 is a characteristic diagram of a conventional pump and a pump operating in accordance with the present invention;

FIG. 4 is a flowchart of a method according to the present invention;

FIG. 5 is a flowchart of another embodiment of the invention;

FIG. 6 is a flowchart of a still another embodiment of the invention;

FIG. 7 is a diagram of a further embodiment of a pump and a control device for such a pump according to the invention;

FIG. 8 is a diagram of another embodiment of a pump and a control device for such a pump according to the invention;

FIG. 9 is a diagram of another embodiment of a pump and pump system according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the method of operation of the pump and pump system are disclosed below.

With reference to FIG. 1, a first embodiment of a pump according to the present invention is described. For purposes of illustration, the described embodiments of the present invention are used in existing submersible pumps containing variable frequency drive means. However, it will be apparent to those skilled in the art that the present invention can also be used in other types of pumps, such as sewage pumps, drainage pumps, sump pumps, etc.

The submersible pump 1 (Fig. 1) contains a variable speed drive unit 2, preferably a variable frequency drive means (VFD unit) connected via a cable 3 to a power source (not shown) supplying, for example, a single-phase voltage or a three-phase voltage. Unlike the known VFD-containing pumps that are designed to receive power in the range of about 200 V to about 250 V, the pump 1 according to the present invention is capable of receiving power in the range of about 90 V to about 250 V. Thus, the pump 1 can used both in countries / regions with a voltage standard of 110 V, and in countries / regions with a voltage standard of 230 V. In addition, pumps according to the prior art are designed to receive power at a frequency of 50 Hz or 60 Hz, which is and Vestnik standard for different countries and / or different regions in the same country. The claimed pump is intended for use in many countries, that is, the input frequency can be at least in the range of 50-60 Hz, but in reality the claimed pump can operate at any available frequency. Thus, this pump can be used with many different power networks, that is, this pump is a pump suitable for operation on a global scale, which can be immediately put into operation.

Node 2 VFD contains an electromagnetic interference filter 4 (EMF filter) mounted on the connecting cable 3 to filter out electromagnetic interference at the input.

The connecting cable 3 is connected to the supply cable of the pump 1. The EMF filter 4 is connected to

- 4 011044 with a rectifier 5, which, in turn, is connected to the converter or inverter 7 through a direct current line 10 including a capacitor 6. An inverter 7 converts direct current into a three-phase current, which is supplied to the pump motor 9 through a connection 8. Function and the components and details of the VFD assembly 2 are well known to those skilled in the art, and therefore are not disclosed in more detail herein.

It is important that the VFD unit 2 is installed with heat shielding from the engine 9 and, at the same time, it is installed with the possibility of heat exchange with the pumped liquid, so that during operation the temperature of the VFD unit 2 is kept at a low level, which eliminates the source of error.

The control device 11 is connected to the pump 1 and is in communication with the VFD unit 2 through a communication bus (not shown) and controls or activates the pump 1, for example, to increase or decrease the speed of the engine 9, to pump more or less liquid, such as water. In addition, the VFD unit 2 comprises a sensor means 16, which is connected to a direct current line 10 and which is designed to obtain the value of the operating parameters of the pump 1 indicating the status of the pump.

The VFD unit 2 transmits to the control device 11 the mentioned values of the operating parameters, which according to a preferred embodiment of the present invention can be a direct current line voltage, a direct current line current, a motor speed or the like. Using these operating parameters, the power of the pump 1 or engine 9, engine torque 9, or other suitable quantities. The control device 11 is arranged so that on the basis of the aforementioned received values of the operating parameters, it is determined whether a predetermined condition is fulfilled, and so that, on the basis of the fulfillment of the aforementioned predetermined condition, to transmit instructions to the VFD unit 2 for controlling the operation of the motor 9 in accordance with the pump conditions.

The control device 11, in turn, is controlled by the processing means 12, which includes the storage means 13. The storage means 13 may include random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM). In this embodiment, the storage means 13 comprises a computer program 14 comprising instructions for turning on a computer or microprocessor, such as processing means 12, for performing the steps of the method according to the present invention. One of ordinary skill in the art will recognize that the storage medium may include various types of physical devices for temporarily and / or permanently storing data, which include semiconductor, magnetic, optical, and combined devices. For example, the storage medium may be implemented using one or more physical devices, such as dynamic RAM, SH1ZU, LOWER. EEPROM, flash memory, etc.

With reference to FIG. 2, an alternative embodiment of the present invention is described. In this embodiment, the control device 11 is connected via an interface node (not shown) to the operator node 22, including keyboard input means 24, which enables the operator to enter, for example, control commands, and a display means or screen 26 for presenting information related to the operation of the pump, such as a history of operating parameters or information about the status of the pump. In one embodiment, the operator unit 22 is a personal computer. The communication line between the pump 1 and the node 22 of the operator may be a wireless line or a wired line. In addition, the operator node 22, in turn, may be connected to a communication network such as the Internet. By means of the operator unit 22, the operator is able to monitor the operation of the pump, as well as various operating parameters associated with its operation, through the display 26. According to another embodiment, the display is a touch screen, in which case several soft keys can be arranged on the screen to enter various commands into the various interfaces 26 shown on the display. In addition, the operator unit may comprise memory means (not shown), which, in turn, may include random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM). It will be apparent to those skilled in the art that the storage medium may include various types of physical devices for temporarily and / or permanently storing data, which include semiconductor, magnetic, optical, and combined devices. For example, the storage medium may be implemented using one or more physical devices, such as dynamic RAM, ROM, EPROM, EEPROM, flash memory, etc.

Data on the operation of pump 1, such as operating parameters, for example, operating time, number of starts, power consumption and alarm data, as well as service records, can be obtained and stored in the registration file in the storage medium 13. The registration file can be presented to the operator through the node 22 of the operator. Moreover, the registration file can be uploaded to the operator unit 22, for example, for storage.

Of course, there are a number of potential design options for the control device 11, for example, the control device may be implemented by a processor including, in particular, programmable instructions for performing the methods of the present invention.

- 5 011044

According to another embodiment, the control device is implemented in the form of a microcircuit or the like of a data medium containing software for performing the functions described herein. In FIG. 7-9 show alternative embodiments of the present invention. In FIG. 7, a control device 11, which can be enclosed in a sealed housing, is mounted on the outer surface of the pump housing. The control device 11 may be attached or fixed to the housing in several possible ways. For example, the device 11 can be fixed by means of screws. In FIG. 8, the control device 11 is in the form of a removable assembly for insertion into the receiving hole 15 of the control device. In FIG. 9, the control device 11 is arranged in the control panel 22.

Below, with reference to FIG. 4, general operations of a pump operation method according to a first aspect of the present invention are described. The first aspect of the method according to the present invention solves the ratchet problem or the dry running problem, which, as described above, leads to increased wear of pump parts such as the impeller and seals, can cause the motor to overheat, and also leads to excessive energy consumption. In addition, pump motors are designed to provide optimum performance when swinging and working in liquids, and, accordingly, prolonged dry running can damage the pump motor. Thus, a first aspect of the present invention provides an efficient method of operating a pump 1 comprising a VFD unit 2, as described with reference to FIG. 1-2 or 7-9, regarding energy consumption, pump life and durability.

First, at step 40, pump operation is initiated, that is, the pump starts. Next, at steps 42 and 44, it is determined whether the predetermined condition is satisfied. For example, in step 42, the pump operates at a first speed level for a predetermined time period and at a second speed level for a predetermined time period. Preferably, the first speed level and the second speed level are low speed levels. For each speed level, the power of engine 9 is determined and later, at step 44, it is checked whether the relation between the speed of engine 9 and engine power is approximately a cubic function (whether the power of the engine is proportional to the cube of the engine speed) using two speed levels and the resulting powers for each of these speed levels. If the ratio is a cubic function, then the pump can operate in normal mode, and if the ratio is not a cubic function, this indicates that pump 1 draws in air and it is determined that the liquid level is too low and the pump cannot work at the desired level speed. This determination is made in the control device 11, for example, in the processing means 12. It should be noted that the relationship between the speed level and the resulting power need not be cubic, and other exponents may be suitable for other mixtures of liquids, i.e. liquids and gases.

If at step 44 it is determined that the fluid level is insufficient, the algorithm proceeds to step 46, where the control device 11 transmits instructions to the VFD unit 2 to stop / suspend the pump for a given period of time, for example, for several minutes, maybe 2 min After this period of time, the algorithm returns to step 42.

On the other hand, if it is determined in step 44 that the liquid level is sufficient, the algorithm proceeds to step 48, in which the speed of pump 1 is increased to the desired level. Thus, pump 1 is now operating normally.

In order to prevent ratchet operation, a check is essentially carried out continuously so that the pump 1 does not suck in air during operation. Therefore, in step 50, by determining whether the second predetermined condition is fulfilled, it is checked whether the liquid level is still sufficient, that is, whether the pump 1 partially or completely sucks air or pumps the liquid. This is done in a substantially continuous manner. In order to perform this check, a suitable working parameter value is obtained by means of the sensor means 16 of the VFD unit 2, and this value is transmitted to the control device 11. For example, DC line voltage, DC current, or the like. can be used directly or can be used to determine, for example, the torque of the engine 9 or preferably the power of the engine 9. A sudden drop in the power of the engine 9 during operation indicates that the pump 1 pumps air instead of liquid.

For example, the second condition is a comparison between the power of the engine 9 and a predetermined base level that can be stored in the storage medium 13, and if the engine power is below a predetermined base level, it is determined that the liquid level is too low. Preferably, the predetermined level may be 70% of the maximum engine power for the current engine speed 9. Alternatively, a step comparable to step 42 may be regularly performed between steps 48 and 50 to determine if liquid is present in the inlet of the pump 1.

If it is determined that the liquid level at the inlet of the pump is sufficient, that is, the power of the engine 9 is higher than the specified level, then the algorithm returns to step 48. On the other hand, if it is determined that the liquid level at the inlet of the pump is too low, that is, the power of the engine 9 below a given level, instead, the algorithm proceeds to step 52, where the pump stops. Subsequently, the algorithm proceeds to step 46, where the pump remains off for a predetermined period of time. After this suspension period, the algorithm returns to step 42.

- 6 011044

Below, with reference to FIG. 5 describes the general principles of a method of operating a pump according to a second aspect of the present invention. The second aspect of the method according to the present invention solves the problem of maintaining the pump power at a substantially constant level over a wide range of flow rates. As shown in FIG. 3 by line 32, by means of the method according to the second aspect, the head / pressure of the pump can be increased by 20-30%. The pump power is maintained at a substantially constant level with a variable pump head by adjusting the speed of the engine. Due to the fact that the pump works more efficiently at low flow rates, a small pump can be used to pump a given amount of fluid, and pump wear can also be reduced. The claimed pump is a universal pump that is designed to be used in many different applications with different requirements. For a given head, high pump capacity can be achieved by adjusting the speed of the pump. A second aspect of the present invention provides an efficient method of operating a pump 1 comprising a VFD unit 2, as described with reference to FIG. 1-2 and 7-9, regarding power consumption and durability.

First, at step 60, the operation of pump 1 is initiated, that is, pump 1 is started. Next, at step 62, the pump operates at the desired speed level. Essentially continuously monitoring the operating parameter of the pump, and the values corresponding to the operating parameter are obtained through the sensor means 16 of the VFD unit 2, these values are transmitted to the control device 11. For example, DC line voltage, DC line current, or the like. can be used directly or can be used to determine, for example, the torque of the engine 9 or preferably the power of the engine 9. At step 64 in the control device 11, for example, the power of the engine 9 is compared with a predetermined base level, for example, the rated power of the engine 9, which may be stored in a storage medium 13, for example in a processing means 12. If it is determined in step 64 that the engine power level is above a predetermined base level, then the algorithm returns to step 62, and the pump is maintained at the desired speed level. On the other hand, if it is determined that the engine power level is below a predetermined level, the algorithm proceeds to step 66, in which the speed required to reach the specified power level is calculated in the processing means 12.

Next, at step 68, the calculated speed is compared with a predetermined maximum speed. If it is determined that the calculated speed is higher than the specified maximum speed, the algorithm proceeds to step 70, where the control device 11 transmits instructions to the VFD unit 2 so that the engine 9 runs at a given maximum speed, and the algorithm returns to step 64. If it is determined that if the calculated speed is lower than the specified maximum speed, the algorithm proceeds to step 72, in which the control device 11 sends instructions to the VFD unit 2 so that the engine 9 runs at the calculated speed. After that, the algorithm proceeds to step 64, where the procedure continues. By maintaining the engine power at a substantially constant level, the head / pressure can be increased at low flow rates, as shown by line 32 in FIG. 3.

Below, with reference to FIG. 6 describes the general principles of a pump operation method according to a third aspect of the present invention. A third aspect of the method according to the present invention solves the problem of clogging or jamming of the inlet channel and / or impeller of the pump 1, which may be caused by particles in the liquid that settle in the inlet channel and in the impeller and form a sludge of a relatively thick or solid consistency. In turn, this entails the need for a large starting torque of the engine in order to start the rotation of the pump impeller. In this case, a large amount of energy is consumed, and the impeller of the pump and the engine wear out. When the pump is idle for a long period of time, even the maximum starting torque may not be enough, and in such cases manual cleaning of the pump is required, and therefore, the reliability when starting pumps operating in such conditions will be low. Thus, a third aspect of the present invention provides an efficient method of operating a pump 1 comprising a VFD unit 2, as described with reference to FIG. 1-2 and 7-9, regarding power consumption, durability and reliability at startup.

First, at step 80, the operation of pump 1 is initiated, that is, pump 1 is started. Next, at 82, the pump is operating at the desired speed level. Next, at step 84, a check is made to see if the pump is clogged / stuck. This can be accomplished, for example, in the following two ways. One way is to measure the operating parameter of the pump and compare it with a given base level, for example, by determining the power of the engine 9 and compare it with a given base level of the power of the engine 9, for example, with the rated power of the engine 9. If the measured engine power is higher than the specified base level , this is an indication of the condition of clogging / seizing. The second method is to monitor the alarm function of the variable-frequency drive means 2, and an alarm indicating the overcurrent of the DC line is used as an indication of a clogged / stuck condition.

If it is determined at step 84 that the pump 1 is not clogged, then the algorithm returns to step 82, which supports the operation of the pump 1. On the other hand, if it is determined that the pump 1 is clogged, the algorithm proceeds to step 86, where the control device 11 sends instructions to the node 2 VFD,

- 7 011044 to start the rotation of the impeller in the opposite direction at a first speed for a predetermined period of time. After a predetermined period of time, pump 1 stops and starts again in the forward direction of rotation.

Preferably, this cycle lasts about 1-10 seconds. Further, in the same manner as in step 84, in step 88 it is checked whether the clogging state has been eliminated. If not, the procedure returns to step 86. This cycle is repeated until the clogging state is cleared. If the clogging state has been eliminated, the algorithm returns to step 82.

To prevent clogging during normal operation, the following procedure can be performed at regular intervals: pump 1 is rotated in the opposite direction at a given speed for a period of time of a given duration, pump 1 is stopped after this period and pump 1 is rotated in the normal rotation direction. Thus, the operational reliability of the pump can be further improved.

The following is a link to FIG. 3. Lines 30 and 32 are examples of the ratio of fluid flow and pressure for a specific pump 1, which is fed by a three-phase voltage of 60 Hz from the VFD unit 2. A frequency of 60 Hz is the standard frequency in electrical networks of some countries, however, through the VFD node 2, this level can be significantly increased, for example, to 150 Hz, and due to this, the lines 30, 32 will be more or less shifted towards the top of the diagram in FIG. 3, and a specific pump can be used for very variable applications and conditions.

Possible modifications of the present invention

Although specific embodiments have been shown and described for purposes of illustration and examples, it will be apparent to those skilled in the art that the particular embodiments shown and described may be superseded by a wide variety of alternative and / or equivalent implementations within the scope of the present invention. Those skilled in the art will appreciate that the present invention may be implemented in a variety of embodiments, including hardware and software implementations, or combinations thereof. For example, many of the functions described herein can be obtained and performed using suitable software in a chip or other storage medium. This application is intended to cover any adaptations or variations of the preferred embodiments described herein. Therefore, the present invention is defined by the wording of the attached claims and its equivalents.

Claims (31)

CLAIM 1. The method of operation of the pump (1), containing the motor (9) and means (2) of a variable frequency drive, designed to control the operation of the motor (9) when connected to the motor (9) and the power cable of the pump (1) and containing a rectifier ( 5), an inverter (7) and a direct current line (10) passing between them, while the pump (1) is connected to a control device (11), characterized in that the values of the operating parameters of the pump (1) indicating the status of the pump are obtained by sensory means (16), which is part of the means (2) frequency-controlled drive and is connected to a direct current line (10), transmit the values of the operating parameters from the means (2) of the variable frequency drive to the control device (11), determine (44, 64, 84) whether the specified condition is fulfilled by means of the device (11 ) control on the basis of the obtained values of the operating parameters and on the basis of the fulfillment of a given condition, transmit instructions from the control device (11) to the variable-frequency drive means (2) in order to control the operation of the motor (9) in accordance with the mentioned states of the pump. 2. The method according to claim 1, characterized in that at the stage of obtaining the operating parameters of the pump (1), at least one of the operating parameters selected from the group consisting of the voltage level of the direct current line, the current level of the direct current line, speed is obtained engine (9) or engine torque (9). 3. The method according to any one of claims 1 or 2, characterized in that it further detects (44, 64, 84) the state of the pump by using the at least one operating parameter. 4. The method according to claim 3, characterized in that the condition of the pump refers to the presence of liquid in the inlet of the pump (1). 5. The method according to claim 4, characterized in that, at the stage of determining the fulfillment of a given condition, start (42) the pump (1) at the first speed level for a given period of time, start (42) the pump (1) at the second speed level for a given period time, it is determined (44) whether the power of the engine (9) is proportional to the cube of the engine speed (9) based on the values of the operating parameters obtained by the sensor means (16) for the first speed level and the second speed level, respectively. 6. The method according to any one of paragraphs.4-5, characterized in that as instructions transmitted from the control device (11) to the variable-frequency drive means (2), use the instruction - 8 011044 start (48) the pump (1) at the desired speed level, if it is determined that the specified condition is fulfilled, or stop (46) the pump (1) for the specified period of time, if it is determined that the specified condition is not fulfilled. 7. The method according to claim 6, characterized in that if the pump (1) is operating at the desired speed level, check (50) for the presence of fluid in the pump inlet (1), for which the values of the operating parameters of the pump (1) are obtained by means of a sensor (16), the aforementioned values of the operating parameters are transferred from the means (2) of the variable frequency drive to the control device (11), it is determined whether the second predetermined condition is met, by means of the control device (11) based on the obtained values of the operating parameters, instructions are transmitted from the device (11) y systematic way in means (2) variable frequency drive on the basis of a predetermined performance condition to control operation of the motor (9) in accordance with said pump conditions. 8. The method according to claim 7, characterized in that to determine the fulfillment of the second predetermined condition, the (50) obtained values of the operating parameters are compared with a given base level. 9. The method according to any one of claims 7 to 8, characterized in that as instructions transmitted from the control device (11) to the variable-frequency drive means (2), use the instruction to start the pump (48) at the desired level speed, if it is determined that the second predetermined condition is satisfied, and stop (52) the pump (1) for a predetermined period of time, if it is determined that the second predetermined condition is not fulfilled. 10. The method according to claim 2, characterized in that it further maintains the value of at least one operating parameter at a substantially constant level. 11. The method according to claim 10, characterized in that, at the stage of determining the fulfillment of a given condition, the pump (1) is started (62) at the desired speed level, based on the engine power values (9) obtained by means of the sensor means (16) for the desired level speed, determine (64) whether the engine power (9) is less than a given basic engine power level (9). 12. The method according to any one of claims 10-11, characterized in that as instructions transmitted from the control device (11) to the variable-frequency drive means (2), use the instruction to start the pump (1) (62) at the desired level speed, if it is determined that the specified condition is not fulfilled, or calculate (66) the engine speed (9) required to achieve the specified basic engine power level (9), if it is determined that the specified condition is satisfied, and start the pump (1) on the aforementioned calculated speed. 13. The method according to p. 12, characterized in that in addition, if the pump (1) operates at a calculated speed, compare (68) the calculated speed of the pump (1) with a given maximum speed of the pump (1), start (70) the pump (1 ) at said calculated speed, if the calculated speed is less than a predetermined maximum speed, or start (72) the pump (1) at said predetermined maximum speed, if the calculated speed is higher than a predetermined maximum speed. 14. The method according to claim 3, characterized in that said condition of the pump relates to blockage of the pump (1). 15. The method according to 14, characterized in that, at the stage of determining the fulfillment of a given condition, the pump (1) is started (82) at the desired speed level, it is determined (84) whether the engine power is (9) higher than the predetermined base engine power level (9) based on engine power values (9) obtained by the sensor means (16) for the desired speed level. 16. The method according to any one of paragraphs.14-15, characterized in that as instructions transmitted from the control device (11) to the variable-speed drive means (2), instructions are used to start the pump (1) (82) at the desired level speed, if it is determined that the specified condition is not fulfilled, or start (86) the pump (1) in the opposite direction at the specified speed for a specified period of time, and start the pump (1) in its normal direction of operation at the desired speed level after a specified period of time work in the opposite direction if Leno that the predetermined condition is satisfied. 17. The method according to p. 16, characterized in that it further repeats (88) the step of determining whether the engine power (9) is higher than a predetermined base level of engine power (9), and repeat the steps specified in clause 16. 18. The method according to 14, characterized in that during operation of the pump (1) at regular intervals, the following steps are performed: start the pump (1) in the opposite direction at a given speed for a given period of time and start the pump (1) in it normal direction of operation at the desired speed level after a specified period of time in reverse. 19. A computer program product (14) loaded into the memory (13) of a digital computing device and containing portions of program code for executing the method according to one of claims 1 to 18, when the computer program product (14) is executed on a digital computing device. 20. A pump containing a motor (9) and means (2) of a variable frequency drive designed to control the operation of the motor (9) when connected to a motor (9) and a pump power cable (1), and containing a rectifier (5), an inverter (7) and the line passing between them (10) is constant - 9 011044 current, while the pump (1) is connected to the control device (11), characterized in that it contains sensor means (16), which is part of the means (2) of the variable frequency drive and connected to the direct current line (10) and designed to obtain the values of the operating parameters of the pump (1) indicating the status of the pump, while the means (2) of the variable frequency drive is designed to transmit to the control device (11) the mentioned values of the operating parameters, while the control device (22) is designed to determine , Follow the important whether a predetermined condition, based on said values of operating parameters, and for transmitting to the means (2) variable frequency drive instruction on the basis of execution of said predetermined condition, to control the operation of the engine (9) according to the states of said pump. 21. The pump according to claim 20, characterized in that the control device (11) is designed to obtain values of at least one of the following operating parameters from the group consisting of the voltage level of the direct current line, the current level in the direct current line, engine torque (9) or engine speed (9). 22. The pump according to item 21, wherein the control device (11) is designed to start the pump (1) at the first speed level for a predetermined period of time, start the pump (1) at the second speed level for a predetermined time period, and determine whether the power of the engine (9) is proportional to the cube of the engine speed (9), based on the values of at least one operating parameter obtained by means of the sensor means (16) for the first speed level and the second speed level, respectively. 23. A pump according to claim 22, characterized in that the control device (11) is designed to start the pump (1) at the desired speed level, if it is determined that the predetermined condition is satisfied, or to stop the pump (1) for a predetermined period of time if it is determined that the specified condition is not satisfied. 24. A pump according to claim 21, characterized in that the control device (11) is designed to maintain the value of at least one operating parameter at a substantially constant level. 25. The pump according to paragraph 24, wherein the control device (11) is designed to start the pump (1) at the desired speed level, determining (64) whether the engine power (9) is less than a given basic engine power level (9) ), based on the engine power values (9) obtained by the sensor means (16) for the desired speed level. 26. A pump according to any one of paragraphs.24 or 25, characterized in that the control device (11) is designed to start the pump (1) at the desired speed level, if it is determined that the specified condition is not satisfied, or calculate (66) the engine speed ( 9) required to achieve a predetermined base level of engine power (9), if it is determined that the predetermined condition is satisfied, and start the pump (1) at said calculated speed. 27. The pump according to p. 26, characterized in that the control device (11) is designed to compare (68) the calculated speed of the pump (1) with a given maximum speed of the pump (1) and start (70) of the pump (1) at the calculated speed, if the calculated speed is less than the set maximum speed, or start (72) of the pump (1) at the set maximum speed, if the calculated speed is higher than the set maximum speed. 28. The pump according to item 21, wherein the control device (11) is designed to start (82) the pump (1) at the desired speed level, determine (84) whether the engine power (9) is higher than the specified base power level the engine (9) based on the engine power values (9) obtained by the sensor means (16) for the desired speed level. 29. The pump according to p. 28, characterized in that the control device (11) is designed to start the pump (1) at the desired speed level, if it is determined that the specified condition is not satisfied, or start (86) the pump (1) in the opposite direction at a given speed for a predetermined period of time, and starting the pump (1) in its normal direction of operation at a desired speed level after said predetermined period of time in reverse direction, if it is determined that the specified condition is satisfied. 30. A pump according to claim 21, characterized in that the control device (11) is designed to start the pump (1) in the opposite direction at a given speed for a predetermined period of time during equal intervals of time, and start the pump (1) in its normal direction of operation at the desired speed level after said predetermined period of time of operation in the opposite direction. 31. A pump station comprising a pump (1) according to any one of claims 20-30 and further comprising an operator assembly (22) comprising input means (24) and display means (26) for presenting information related to the operation of the pump ( one).