WO2020054881A1

WO2020054881A1 - Decanter-type centrifugal dehydrator capable of saving energy

Info

Publication number: WO2020054881A1
Application number: PCT/KR2018/010555
Authority: WO
Inventors: 박지훈
Original assignee: 주식회사 로얄정공
Priority date: 2018-09-10
Filing date: 2018-09-10
Publication date: 2020-03-19

Abstract

A disclosed decanter-type centrifugal dehydrator comprises: a rotating bowl; a scroll; a main motor for providing power to rotate the bowl; a differential-speed control motor which provides power to control the rotation speed of the scroll and is a generator-combined motor for generating electric energy while its own shaft rotates without consuming electric energy; a gear box mechanically connected to the bowl, the differential-speed control motor, and the scroll so as to determine the rotation speed of the scroll according to the rotation speed of the bowl and the rotation speed of the shaft of the differential-speed control motor; and an electric power storage unit which comprises a super capacitor and is a unit for storing surplus electric energy and supplying the electric energy as necessary.

Description

Energy-saving decanter type centrifugal dehydrator

The present invention relates to a decanter-type centrifugal dehydrator that solidifies and discharges sludge containing a lot of water through dehydration treatment, and more particularly, to an energy-saving decanter-type centrifugal dehydrator.

In general, sludges with an average water content of 75% are generated in industrial sites and sewage treatment processes. When sludge containing a large amount of water is buried or dumped into the sea, serious environmental pollution problems are caused. Industrial sludge must be landfilled or incinerated, as sludge marine dumping has been banned in recent years as part of efforts to prevent environmental pollution. Sludge containing a large amount of water greatly increases transportation costs for transporting to landfills or incinerators and makes incineration difficult. Therefore, first, a dewatering treatment using a decanter-type centrifugal dehydrator is performed to convert it into a sludge cake having a low water content.

A conventional decanter-type centrifugal dehydrator is provided with a bowl extending in a horizontal direction in a pipe form and rotating, and a scroll rotating at a rotational speed different from the rotational speed of the bowl inside the bowl. do. The rotational speed of the bowl is determined by the rotational speed of the main motor, and the rotational speed of the scroll is determined by the rotational speed of the bowl and the rotational speed of the vehicle speed control motor.

When the rotational speed of the bowl and the scroll is determined only by the power of the main motor, the deviation of the dewatering effect is increased depending on the amount of sludge to be input, thereby deteriorating the quality of the dewatering operation and actively dewatering effect, that is, the water content of the sludge cake Since it cannot be adjusted, the rotation speed of the scroll is controlled using a vehicle speed control motor. However, as the vehicle speed control motor is used, there is a problem in that power loss is increased and energy consumption is increased to increase driving costs.

The present invention provides an energy-saving decanter-type centrifugal dehydrator, which is a decanter-type centrifugal dehydrator equipped with a main motor and a vehicle speed control motor for rotating the bowl and the scroll, reducing energy consumption and resulting operating costs.

In the present invention, a rotating bowl, a scroll rotating inside the bowl, a main motor providing power to rotate the bowl, and if its own shaft rotates without consuming electrical energy A generator combined motor that generates electrical energy, and is mechanically connected to a differential-speed control motor, the bowl, the vehicle speed control motor, and the scroll that provides power to control the rotational speed of the scroll. , A gear box for determining the rotational speed of the scroll according to the rotational speed of the bowl and the rotational speed of the shaft of the vehicle speed control motor, and a unit that accumulates and supplies extra electrical energy when necessary In the meantime, it has a power storage unit including a super capacitor, and the main motor while sludge is supplied into the bowl. The voltage supplied is a normal voltage section supplied at a constant size greater than 0 V (volt), and a voltage cutoff section having a voltage magnitude of OV alternately exists, and during the voltage cutoff section, the bowl rotates inertia and the vehicle speed control motor Provides an energy-saving decanter-type centrifugal dehydrator that generates electrical energy, accumulates the electrical energy in the supercapacitor, and discharges the electrical energy accumulated in the supercapacitor during the normal voltage period to be supplied to the main motor. do.

The energy-saving decanter-type centrifugal dehydrator of the present invention includes a main motor inverter that supplies power to the main motor, a vehicle speed control motor inverter that supplies power to the vehicle speed control motor, and the main motor inverter and the vehicle speed control. A controller that controls the rotation speed of the bowl and the rotation speed of the scroll by controlling a common DC bus, and the main motor inverter and the vehicle speed control motor inverter to enable power distribution between motor inverters. ), And the controller controls the main motor inverter to control the voltage supplied to the main motor.

The power storage unit is connected to the common DC bus, and the power storage unit further includes a voltage measurement sensor that measures a voltage between a positive electrode and a negative electrode of the common DC bus, and the voltage measurement sensor. When the voltage measured at is greater than or equal to the preset reference voltage, electrical energy is accumulated in the super capacitor through the common DC bus, and when the voltage measured by the voltage measurement sensor is lower than the reference voltage, accumulation is accumulated in the super capacitor. The controller may control the power storage unit such that the electric energy discharged is discharged through the common DC bus.

The energy-saving decanter-type centrifugal dehydrator of the present invention further includes a main motor encoder that measures the rotational speed of the shaft of the main motor, and the controller measures the main motor encoder during the voltage cutoff period. When the rotational speed of the bowl calculated through the value reaches a predetermined lower limit speed, the main motor inverter may be controlled such that the voltage supplied to the main motor is switched from the voltage blocking section to the normal voltage section.

The lower limit speed may be a speed belonging to 85 to 90% of the rotation speed of the bowl in the normal voltage section.

The energy-saving decanter-type centrifugal dehydrator of the present invention further includes a main motor encoder for measuring the rotational speed of the shaft of the main motor, and a scroll encoder for measuring the rotational speed of the scroll, and the sludge ( sludge) is supplied, so that the difference between the rotational speed of the bowl calculated through the measurement value of the main motor encoder and the rotational speed of the scroll calculated through the measurement value of the scroll encoder does not exceed a preset allowable range. , The controller may control the vehicle speed control motor inverter in a feedback control method.

The allowable range belongs to 5 to 50 rpm, and the rotational speed of the scroll may be smaller than the rotational speed of the bowl.

According to the present invention, while the electric energy supply to the main motor is intermittently blocked, the electric energy generated by the vehicle speed control motor accumulates in the super capacitor, and when the electric energy supply to the main motor resumes, the electricity accumulated in the super capacitor Energy is discharged and supplied to the main motor. Therefore, while maintaining a good work quality of the sludge dewatering operation using a decanter-type centrifugal dehydrator, energy consumption input to the dewatering operation and the resulting operation cost can be reduced.

1 is a block diagram of a decanter-type centrifugal dehydrator according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of the charging unit of FIG. 1.

3 is a graph showing the magnitude of the voltage supplied to the main motor of FIG. 1.

4 is a graph showing the rotational speed of the bowl and scroll of FIG. 1.

5 is a block diagram of a decanter-type centrifugal dehydrator according to a second embodiment of the present invention.

6 is a configuration diagram of a decanter-type centrifugal dehydrator according to a third embodiment of the present invention.

Hereinafter, an energy-saving decanter-type centrifugal dehydrator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Terminology used in the present specification are terms used to properly express a preferred embodiment of the present invention, which may vary according to a user's or operator's intention or customs in the field to which the present invention pertains. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

1 is a configuration diagram of a decanter-type centrifugal dehydrator according to a first embodiment of the present invention, and FIG. 2 is a circuit diagram of the charging unit of FIG. 1. 1 and 2 together, the energy-saving decanter-type centrifugal dehydrator 10A according to the first embodiment of the present invention includes a rotating bowl 12 and a rotating bowl 12 inside. A rotating scroll (17), a feed pipe (11) for supplying a sludge having a high water content inside the scroll (17), and providing power to rotate the bowl (12) The main motor 21, the differential-speed control motor 26 that provides power for controlling the rotational speed of the scroll 17, the bowl 12, the vehicle speed control motor 26, and Mechanically connected to the scroll 17, to determine the rotational speed of the scroll 17 according to the rotational speed of the bowl 12 and the rotational speed of the shaft 27 of the vehicle speed control motor 26 A gear box 31 is provided.

The bowl 12 is a member extending in the form of a pipe in a horizontal direction, and a pulley 25 is coupled to one end of the bowl 12, and is also applied to the shaft 22 of the main motor 21. Pulleys 23 are coupled, and the pair of

pulleys

23 and 25 are wound and connected by a timing belt 24. Accordingly, the bowl 12 is rotated by the rotational power of the main motor 21. The rotational speed of the bowl 12 is determined by the rotational speed of the main motor shaft 22.

The scroll 17 is a member extending in a horizontal direction from inside the bowl 12, and includes a hollow central pipe and a screw blade 18 installed on the outer peripheral surface of the central pipe. The end of the feed pipe 11 is inserted up to the inside of the central pipe of the scroll 17.

One side of the gear box 31 is connected to the other side of the bowl 12. The pulley 30 is coupled to the other side of the gear box 31, the pulley 28 is also coupled to the shaft 27 of the vehicle speed control motor 26, and the pair of

pulleys

28, 30 is a timing belt ( 29). Accordingly, the rotational power of the vehicle speed control motor 26 is transmitted to the gear box 31. The output side shaft 31a of the gear box 31 is connected to the scroll 17. As a result, the rotation speed of the bowl 12, the rotation speed of the vehicle speed control motor shaft 27, and the rotation of the output shaft 31a and the scroll 17 by the gear ratio inside the gear box 31 Speed is determined. On the other hand, the vehicle speed control motor 26 is a so-called 'generator combined motor' with a built-in generator. Therefore, when the shaft 27 of the vehicle speed control motor 26 rotates without consuming electric energy, that is, without supplying electric energy, electric energy is generated in the vehicle speed control motor 26.

When the sludge with a high percentage of moisture content flows into the inner space of the scroll 17 through the feed pipe 11 when the bowl 12 and the scroll 17 rotate, the rotation centrifugal force of the scroll 17 By this, the sludge is discharged to the inner space of the bowl 12 through the sludge outlet 19. Since the rotary centrifugal force of the bowl 12 acts on the sludge discharged through the sludge outlet 19, water (H ₂ O) contained in the sludge is dehydrated and separated by a density difference.

The dewatered sludge being pushed by the rotating screw blade 18 of the scroll 17 is continuously dewatered and transferred to one side of the bowl 12 and discharged to the outside of the bowl 12 through the sludge outlet 14. The water dehydrated from the sludge is discharged by moving to the other side of the bowl 12.

The decanter-type centrifugal dehydrator 10A includes a main motor inverter 40 for supplying power to the main motor 21, a vehicle speed control motor inverter 42 for supplying power to the vehicle speed control motor 26, Rotational speed of the common DC bus (45) and the shaft (22) of the main motor (21) to connect power between the main motor inverter (40) and the vehicle speed control motor inverter (42). A main motor encoder (32) for measuring, and a scroll encoder (33) for measuring the rotational speed of the scroll (17), that is, the rotational speed of the output shaft (31a) of the gear box (31), and the main motor inverter (40) and a vehicle speed control motor controller (42) to control the rotational speed of the bowl (12) and the scroll (17) to further control the controller (55A).

The main motor inverter 40 and the vehicle speed control motor inverter 42 are connected to a three-phase AC power supply 5, and the AC (AC) supplied from the power supply 5 is connected to a common DC bus 45 to direct current (AC). DC). Direct current (DC) distributed to the main motor inverter 40 and the vehicle speed control motor inverter 42 through the common DC bus 45 is converted back to AC and supplied to the main motor 21 and the vehicle speed control motor 26 do.

The decanter-type centrifugal dehydrator 10A further includes a power storage unit 70 connected to a common DC bus 45 and a resistor 49 connected to at least one of the main motor inverter 49 and the vehicle speed control motor inverter 42. Be equipped. The power storage unit 70 is a unit that accumulates excess electrical energy and supplies it when necessary, a super capacitor 71, a voltage measurement sensor 73, a charge switch 75, and a discharge switch 80 It is provided.

The supercapacitor 71 is a capacitor having a greatly enhanced electric capacity than a normal capacitor to be usable as a secondary battery. The capacitance of a typical capacitor is 1 to several tens of μF (microfarad), whereas that of a supercapacitor ranges from 1 to 10 F (farad). The supercapacitor 71 can be charged and discharged much more repeatedly than the secondary battery, and thus has excellent durability, and is economical at a price of about 1/2 to 1/4 of the price of the secondary battery. In addition, the supercapacitor 71 has a characteristic of discharging and supplying large electric energy at the beginning of discharge, and is useful when it is necessary to generate a large amount of power at the beginning of operation using an electric motor.

Since the shaft 27 of the vehicle speed control motor 26 and the gear box 31 are connected to transmit rotational power, even if electric energy is not supplied to the vehicle speed control motor 26, when the bowl 12 rotates, the vehicle speed control motor The shaft 27 can rotate. For example, in the voltage blocking section (between T1 to T2) where the magnitude of the voltage supplied to the main motor 21 to be described later is 0V (see FIG. 3), even if electric energy is not supplied to the vehicle speed control motor 26, that is, Even if the magnitude of the voltage supplied to the vehicle speed control motor 26 is OV, the vehicle speed control motor shaft 27 rotates, so that electric energy may be generated in the vehicle speed control motor 26. The electric energy generated by the vehicle speed control motor 26 flows into the vehicle speed control motor inverter 42 and is accumulated in the super capacitor 71 of the power storage unit 70 through the common DC bus 45.

Then, when the normal voltage section (between T2 and T3) (see FIG. 3) in which a voltage of a constant magnitude is supplied to the main motor 21 after the voltage cutoff period (see FIG. 3) arrives, the supercapacitor 71 is provided during the normal voltage section. The accumulated electrical energy is discharged and supplied to the main motor 21 through the common DC bus 45 and the main motor inverter 40. On the other hand, when the electric energy generated by the vehicle speed control motor 26 and supplied through the common DC bus 45 exceeds the electric capacity of the super capacitor 71, the excess electric energy is consumed as heat energy in the resistor 49 Can be.

The voltage measurement sensor 73 is a sensor that measures the voltage between the positive electrode and the negative electrode of the common DC bus 45, and the measurement signal is transmitted to the controller 55A. When the decanter-type centrifugal dehydrator 10A starts to operate, the rotational speed of the bowl 12 gradually increases from 0 rpm to the normal operating rotational speed R1 rpm (see FIG. 4). After the rotation speed of the bowl 12 reaches the normal operation rotation speed, the voltage measured by the voltage measurement sensor 73, that is, the voltage calculated from the measurement signal of the voltage measurement sensor 73 by the controller 55A If it is greater than or equal to the preset reference voltage, the controller 55A controls the power storage unit 70 so that electrical energy is accumulated in the super capacitor 71 through the common DC bus 45. On the contrary, if the voltage measured by the voltage measurement sensor 73 is lower than the reference voltage, the controller 55A stores the electrical energy accumulated in the super capacitor 71 through the common DC bus 45 so that the power storage unit ( 70).

The charge switch 75 and the discharge switch 80 are on-off (ON-OFF) switches when the supercapacitor 71 is charged or discharged. In the example illustrated in FIG. 2, a solid state relay (SSR) is included. It is configured by. Specifically, the charging switch 75 and the discharging switch 80 respectively receive light emitting diodes (LEDs) 76 and 81 that emit light, and light reception of light emitted from the LEDs 76 and 81 ( Phototransistors 77 and 82 that open and close the current depending on whether or not the light is provided. The charge switch 75 and the

LEDs

76 and 81 of the discharge switch 80 are connected to the controller 55A to enable electrical signal transmission. The

photo transistors

77 and 82 of the charge switch 75 and the discharge switch 80 are connected in parallel between the anode and the cathode of the common DC bus 45, and the photo transistor 77 of the charge switch 75 The supercapacitor 71 and the photo transistors 82 of the discharge switch 80 are each connected in series.

If the voltage measured by the voltage measurement sensor 73 is greater than or equal to a preset reference voltage, the LED 76 of the charging switch 75 irradiates light by the control signal of the controller 55A, and the discharge switch 80 ) LED 81 does not emit light. Then, the current through the photo transistor 77 of the charge switch 75 is opened (ON), and the current through the photo transistor 82 of the discharge switch 80 is blocked (OFF). Accordingly, electric energy is charged in the supercapacitor 71. On the other hand, if the voltage measured by the voltage measurement sensor 73 is smaller than a preset reference voltage, the LED 76 of the charging switch 75 is not irradiated with light by the control signal of the controller 55A and discharges. The LED 81 of the switch 80 emits light. Then, the current through the photo transistor 77 of the charge switch 75 is cut off (OFF), and the current through the photo transistor 82 of the discharge switch 80 is opened (ON). Accordingly, electrical energy accumulated in the supercapacitor 71 is discharged.

The photo transistor 77 of the charge switch 75 and the photo transistor 82 of the discharge switch 80 are connected in series with

diodes

79, 84 and fuses 78, 83, respectively. . The

diodes

79 and 84 are elements for preventing the occurrence of a reverse current at the time of charging and discharging of the super capacitor 71, respectively, and the

fuses

78 and 83 are at the time of power supply of the super capacitor 71, respectively. And an element for preventing fire due to overcurrent or overvoltage during discharge.

The rotation speed measurement value of the main motor shaft 22 measured by the main motor encoder 32 is transmitted to the controller 55A, and the controller 55A calculates the rotation speed of the bowl 12 from this measurement value. In the scroll encoder 33, the rotational speed of the direct scroll 17 is measured, and this rotational speed measurement value is transmitted to the controller 55A. Meanwhile, as illustrated in FIG. 1, a decanter-type centrifugal dehydrator according to a modified embodiment of the present invention may include a vehicle speed control motor encoder that measures the rotational speed of the vehicle speed control motor shaft instead of the scroll encoder. In this case, the rotation speed measurement value of the vehicle speed control motor shaft is transmitted to the controller, and the controller calculates the rotation speed of the scroll 17 from the rotation speed measurement value of the main motor shaft and the rotation speed measurement value of the vehicle speed control motor shaft.

3 is a graph showing the magnitude of the voltage supplied to the main motor of FIG. 1, and FIG. 4 is a graph showing the rotational speed of the bowl and scroll of FIG. 1. 1 to 4 together, while the sludge is supplied into the bowl 12, that is, while the sludge is supplied to the interior space of the scroll 17 through the feed pipe 11, it is supplied to the main motor 21 The controller 55A controls the main motor inverter 40 such that a normal voltage section supplied with a constant size (V1) greater than 0V (volt) and a voltage blocking section having a voltage level of 0V alternately exist at the voltage to be applied. . In FIG. 3, the normal voltage section is a T0 to T1 section and a T2 to T3 section, and a voltage blocking section is a T1 to T2 section.

Since there is no electric energy supplied to the main motor 21 during the voltage cutoff period, electric energy is reduced compared to a conventional decanter type centrifugal dehydrator that continuously supplies electric energy of a normal voltage without a voltage cutoff period. The bowl 12 continues to rotate inertia even during the voltage cutoff period.

In Figure 4, the operation of the decanter-type centrifugal dehydrator 10A is started, and the rotational speed of the bowl 12 rises from 0 rpm to R1 rpm, which is the normal operation speed, through the feed pipe 11. No sludge is added. At a time T0 when the rotational speed reaches R1 rpm, the normal voltage section starts, and sludge input through the feed pipe 11 is started. For example, the R1 rpm may be 1800 to 3000 rpm. When the voltage cutoff period starts after the normal voltage period at time T1, the bowl 12 rotates by inertia, but the rotational speed gradually decreases due to the load of the gear box 31 and the friction load of the bearing (not shown). .

If the rotational speed of the bowl 12 is excessively reduced, the dehydration performance is adversely affected, so the elapsed time of the voltage blocking section is appropriately limited by the controller 55A. Specifically, as described above, the controller 55A periodically and repeatedly calculates the rotational speed of the bowl 12 through the measurement value of the rotational speed of the main motor shaft 22 measured in the main motor encoder 32. When the rotation speed of the calculated bowl 12 reaches a predetermined lower limit speed during the voltage blocking section, the controller 55A causes the voltage supplied to the main motor 21 to switch from the voltage blocking section to a normal voltage section. The motor inverter 40 is controlled.

3 and 4, the rotational speed R2 is the lower limit speed, and the time T2 is the time when the rotational speed of the bowl 12 becomes R2, from which the normal voltage section is resumed. Here, the lower limit speed R2 may be a speed belonging to 85 to 90% of the normal operation rotation speed R1 in the normal voltage section. For example, if R1 is 2000 rpm, R2 may be a specified work speed from 1700 to 1800 rpm. Even if the normal voltage section is resumed, the rotation speed of the bowl 12 is not immediately restored to the normal operation rotation speed R1, but after a slight delay, the rotation speed is restored to the normal operation rotation speed R1.

The ratio of the duration of the normal voltage section to the duration of the voltage cutoff period may be 1 to 3 times. 3 and 4, the ratio is a time between T0 and T1 to a time between T1 and T2. For example, the duration of the normal voltage section may be 5 minutes, and the duration of the voltage blocking period may be 5 minutes, in which case the ratio is 1 time. If the ratio is less than 1 time, the voltage cutoff section is started again after the transition from the voltage cutoff section to the normal voltage section and the bowl 12 does not recover enough rotational acceleration, so the bowl 12 rotates in the voltage cutoff section. The speed decreases drastically and can adversely affect sludge dewatering performance. Conversely, if the ratio is greater than 3 times, the total time of the voltage cut-off period is reduced, so that the energy saving effect may be insufficient.

Good sludge dewatering performance is maintained only when the difference between the rotational speed of the bowl 12 and the rotational speed of the scroll 17 does not exceed a preset allowable range while the sludge is supplied into the bowl 12 and the sludge is dewatered. . As described above, the controller 55A periodically calculates the rotational speed of the bowl 12 through the rotational speed measurement value of the main motor shaft 22 measured by the main motor encoder 32 repeatedly, and the The difference between the rotational speed of the bowl 12 and the rotational speed of the scroll 17 is calculated by comparing the measured rotational speed of the scroll 17 measured by the rotational speed and the scroll encoder 33. Then, the controller 55A controls the vehicle speed control motor inverter 42 by a feedback control method so that the difference between the rotational speed of the bowl 12 and the rotational speed of the scroll 17 does not exceed a preset allowable range. do.

In the decanter-type centrifugal dehydrator 10A, the rotational speed of the scroll 17 is kept smaller than the rotational speed of the bowl 12, for example, the allowable range of the rotational speed difference may be 5 to 50 rpm. In Fig. 4, the rotation speed R3 is the normal operation rotation speed of the scroll 17 when the bowl 12 is the normal operation rotation speed R1. As a specific example, assuming that R1 is 2000 rpm and the allowable range of the rotational speed difference between the bowl 12 and the scroll 17 is 30 rpm, the controller 55A periodically and repeatedly repeats the normal operating rotational speed R3 of the scroll 17. Calculate, and when it is determined that R3 is greater than or less than 1970 rpm, the vehicle speed control motor inverter 42 is controlled to converge R3 to 1970 rpm to adjust the voltage level supplied to the vehicle speed control motor 26. However, when it is determined that R3 is equal to 1970 rpm, the controller 55A maintains the voltage level supplied to the vehicle speed control motor 26 through the vehicle speed control motor inverter 42.

In FIG. 4, the rotation speed R4 is the lower speed of the scroll 17 when the bowl 12 is the lower speed R2 in the voltage cutoff period. In the voltage cutoff period, electric energy is not supplied to the vehicle speed control motor 26 as well as the main motor 26, and the rotational speeds of the bowl 12 and the scroll 17 gradually decrease. The difference between the rotational speed of the bowl (12) and the rotational speed of the scroll (17) gradually increases as time elapses after the start of the voltage blocking section, so that the difference in rotational speed between the two (12, 17) is the maximum value of the allowable range, For example, when it exceeds 50 rpm, it is switched to the normal voltage section (T2 to T3). The lower speed R2 of the bowl 12 and the lower speed R4 of the scroll 17 respectively rotate the bowl 12 when the difference in rotational speed between the bowl 12 and the scroll 17 reaches the maximum value of the allowable range. It becomes the speed and the rotation speed of the scroll 17.

When the rotational speed of the bowl 12 reaches the lower limit speed R2, the voltage supplied to the bowl 12 is switched from the voltage cutoff section to the normal voltage section, and the rotational speed of the bowl 12 gradually rises to the normal driving speed R1. , After the rotation speed of the scroll 17 also reaches the lower limit speed R4, it rises again to the normal operation rotation speed R3.

As described above, when the voltage cutoff period starts at time T1, the electric energy supply is also cut off to the vehicle speed control motor 26. Nevertheless, the shaft 27 of the vehicle speed control motor 26 rotates to generate electric energy. , This electrical energy is accumulated in the supercapacitor 71 of the charging unit 70. In addition, when the normal voltage section restarts at time T2, electrical energy accumulated in the supercapacitor 71 is discharged and supplied to the main motor 21. Unlike the secondary battery, the supercapacitor 71 has a characteristic of supplying discharge at the initial stage of discharge, so that the shaft 22 of the main motor 21 has a large torque at the beginning of the normal voltage period restarted after the voltage cutoff period. Rotates to Due to this, the rotational speed of the bowl 12 and the scroll 17 can be quickly recovered to the normal driving rotational speeds R1 and R3.

During the voltage cutoff period, the charging switch 75 is turned on so that current flows, and the discharge switch 80 is turned off so that the current is cut off, so that the supercapacitor 71 is charged, and during the normal voltage section The charging switch 75 is turned off so that the current is cut off, and the discharge switch 80 is turned on so that current flows, so that the electric energy accumulated in the supercapacitor 71 can be discharged. ), The reference voltage may be set to an appropriate value.

According to the decanter-type centrifugal dehydrator 10A described above, the electric energy generated by the vehicle speed control motor 26 is accumulated in the supercapacitor 71 while the electric energy supply to the main motor 21 is intermittently blocked, When the electric energy supply to the main motor 21 is restarted, the electric energy accumulated in the super capacitor 71 is discharged and supplied to the main motor 21. Therefore, while maintaining a good working quality of the sludge dewatering operation using the decanter-type centrifugal dehydrator 10A, it is possible to reduce the energy consumption and the operation cost resulting from the dewatering operation.

5 is a block diagram of a decanter-type centrifugal dehydrator according to a second embodiment of the present invention. 5, the decanter-type centrifugal dehydrator 10B according to the second embodiment of the present invention is a decanter-type centrifugal dehydrator 10A according to the first embodiment of the present invention described with reference to FIGS. 1 to 4 Since a configuration similar to that is provided, the following will be described in detail only for the configuration that is different. The same reference numbers in FIGS. 1 and 5 have the same configuration and function, and thus redundant description will be omitted. The decanter-type centrifugal dehydrator 10B according to the second embodiment of the present invention further includes a secondary battery 51 connected to the common DC bus 45 instead of the charging unit 70 of FIG. 1.

The electric energy generated by the vehicle speed control motor 26 which is a generator combined motor is stored in the secondary battery 51 through the common DC bus 45 and the vehicle speed control motor inverter 42. The electric energy stored in the secondary battery 51 is supplied to the main motor 21 through the common DC bus 45 and the main motor inverter 40. The controller 55B also functions to control charging and discharging of the secondary battery 51.

6 is a configuration diagram of a decanter-type centrifugal dehydrator according to a third embodiment of the present invention. 6, the decanter-type centrifugal dehydrator 10C according to the third embodiment of the present invention is a decanter-type centrifuge according to the first and second embodiments of the present invention described with reference to FIGS. 1 to 5 Since it has a similar configuration to the

separation dehydrators

10A, 10B, only the different configurations will be described in detail below. In FIG. 1, FIG. 5, and FIG. 6, the same reference numerals have the same configuration and function, and thus redundant description will be omitted. In the decanter-type centrifugal dehydrator 10C according to the third embodiment of the present invention, the main motor 56 is a motor that generates power to rotate the bowl 12.

On the other hand, the main motor 56 is a generator combined motor that generates electric energy when its shaft 57 rotates without consuming electric energy. Incidentally, since the decanter-type centrifugal dehydrator 10A according to the first embodiment of the present invention is described, the bowl 12 rotates by inertia in the voltage cutoff section after the normal voltage section mentioned, so that the main motor 56 Although the electric energy supply is cut off, the main motor shaft 57 continues to rotate, thereby generating electric energy.

The decanter-type centrifugal dehydrator 10C includes a power controller 58 and a secondary battery 52 in place of the power storage unit 70 of FIG. 1. The power controller 58 converts electrical energy from the main motor 56 when it is generated to direct it to the common DC bus 45. That is, when electric energy is generated from the main motor 56, the switch 59 electrically connects the main motor 56 and the power controller 58 as shown by a solid line in FIG. 6, so that the main motor 56 The generated electrical energy flows into the power controller 58, and AC power is converted into DC electricity in the power controller 58 and supplied to the common DC bus 45. On the other hand, when switching from the voltage cutoff section to the normal voltage section, the switch 59 electrically disconnects the main motor 56 and the power controller 58, as shown by the dashed line in FIG. 6, and the main motor inverter 40 Electrical energy is supplied to the main motor 56 through.

The secondary battery 52 is connected to a common DC bus 45. The secondary battery 52 stores electrical energy generated by the main motor 56 through the common DC bus 45 and supplies the stored electrical energy to the main motor inverter 40. Electricity supplied to the main motor inverter 40 is supplied to the main motor 21. The controller 55C also performs a function of controlling ON / OFF of the switch 59 of the power controller 58 and a function of controlling charging and discharging of the secondary battery 52.

The secondary battery 52, the power controller 58, and the switch 59 constitute a so-called 'energy storage system (ESS)' that stores excessively produced electrical energy and transmits it when it is temporarily insufficient.

According to the energy-saving decanter-type

centrifugal dehydrator

10B, 10C according to the second and third embodiments of the present invention described above, the voltage applied to the

main motors

21 and 56 is maintained while the sludge dewatering function is maintained. Intermittent shut-off can reduce energy consumption and reduce operating costs. In addition, during the voltage cutoff period, the electric energy generated by the vehicle speed control motor 26 or the main motor 56 is stored in the

secondary batteries

51 and 52, and the rotational power of the bowl 12 and the scroll 17 is stored. As it can be used, energy can be further reduced.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom. Therefore, the true protection scope of the present invention should be defined only by the appended claims.

The present invention can be used in the sewage treatment industry and the pollution prevention industry.

Claims

A rotating bowl; A scroll rotating inside the bowl; A main motor that provides power to rotate the bowl; A generator combined motor that generates electric energy when its shaft rotates without consuming electric energy, comprising: a differential-speed control motor that provides power to control the rotational speed of the scroll; A gear box mechanically connected to the bowl, the vehicle speed control motor, and the scroll to determine the rotation speed of the scroll according to the rotation speed of the bowl and the rotation speed of the shaft of the vehicle speed control motor. ); And a power storage unit including a super capacitor as a unit that accumulates and supplies extra electrical energy when necessary.

While the sludge is supplied into the bowl, the voltage supplied to the main motor alternates between a normal voltage section supplied at a constant size greater than 0 V (volt) and a voltage blocking section having a voltage magnitude of OV. ,

During the voltage cutoff period, the bowl rotates inertia and electrical energy is generated in the vehicle speed control motor to accumulate the electrical energy in the supercapacitor, and discharges the electrical energy accumulated in the supercapacitor during the normal voltage section Energy-saving decanter-type centrifugal dehydrator, characterized in that supplied to the motor.
According to claim 1,

A main motor inverter that supplies power to the main motor; A vehicle speed control motor inverter supplying power to the vehicle speed control motor; A common DC bus that connects the main motor inverter and the vehicle speed control motor inverter to enable power distribution; And, a controller for controlling the rotational speed of the bowl and the rotational speed of the scroll by controlling the main motor inverter and the vehicle speed control motor inverter;

Energy-saving decanter-type centrifugal dehydrator, characterized in that the controller controls the main motor inverter to control the voltage supplied to the main motor.
According to claim 2,

The power storage unit is connected to the common DC bus,

The power storage unit further includes a voltage measurement sensor that measures a voltage between a positive electrode and a negative electrode of the common DC bus,

When the voltage measured by the voltage measurement sensor is greater than or equal to a preset reference voltage, electrical energy is accumulated in the super capacitor through the common DC bus, and when the voltage measured by the voltage measurement sensor is lower than the reference voltage, the An energy-saving decanter-type centrifugal dehydrator, characterized in that the controller controls the power storage unit so that electric energy accumulated in a supercapacitor is discharged through the common DC bus.
According to claim 2,

Further comprising a main motor encoder (encoder) for measuring the rotational speed of the shaft of the main motor,

In the controller, when the rotational speed of the bowl, which is calculated through the measured value of the main motor encoder during the voltage blocking section, reaches a predetermined lower limit speed, the voltage supplied to the main motor is the normal voltage in the voltage blocking section. Energy-saving decanter-type centrifugal dehydrator, characterized in that to control the main motor inverter to switch to the section.
According to claim 4,

The lower speed is characterized in that the speed belongs to 85 to 90% of the rotational speed of the bowl in the normal voltage section, energy-saving decanter centrifugal dehydrator.
According to claim 2,

A main motor encoder for measuring the rotational speed of the shaft of the main motor; And a scroll encoder for measuring the rotational speed of the scroll.

While sludge is supplied into the bowl, a difference between the rotational speed of the bowl calculated through the measurement value of the main motor encoder and the rotational speed of the scroll calculated through the measurement value of the scroll encoder is previously set. In order not to exceed the set allowable range, the controller is characterized in that it controls the vehicle speed control motor inverter by a feedback control method, an energy-saving decanter-type centrifugal dehydrator.
The method of claim 6,

The allowable range belongs to 5 to 50 rpm, characterized in that the rotational speed of the scroll is smaller than the rotational speed of the bowl, energy-saving decanter centrifugal dehydrator.