CN108547760B - Frequency follow-up control method for lift pump of water treatment - Google Patents
Frequency follow-up control method for lift pump of water treatment Download PDFInfo
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- CN108547760B CN108547760B CN201810351894.7A CN201810351894A CN108547760B CN 108547760 B CN108547760 B CN 108547760B CN 201810351894 A CN201810351894 A CN 201810351894A CN 108547760 B CN108547760 B CN 108547760B
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- liquid level
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- lift
- pump
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 26
- 239000007788 liquid Substances 0.000 claims abstract description 77
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 230000001681 protective effect Effects 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 3
- 230000003068 static effect Effects 0.000 claims description 3
- 238000010276 construction Methods 0.000 abstract description 4
- 238000012544 monitoring process Methods 0.000 abstract description 4
- 238000012423 maintenance Methods 0.000 abstract description 3
- 230000001131 transforming effect Effects 0.000 abstract description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 230000007774 longterm Effects 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/06—Control using electricity
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B23/00—Pumping installations or systems
- F04B23/04—Combinations of two or more pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B51/00—Testing machines, pumps, or pumping installations
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Positive-Displacement Pumps (AREA)
- Control Of Non-Positive-Displacement Pumps (AREA)
Abstract
The invention discloses a frequency follow-up control method for a lift pump for water treatment, which can adjust the flow by using the frequency adjusting function of a frequency converter, automatically control the change of the liquid level of a water collecting well caused by the change of the flow of a water inlet pipe network and continuously, timely and reliably realize the flow control function of the lift pump. The method of the invention requires few monitoring and execution devices, but is extremely easy to implement for automatic control. The operation process can be completely separated from the intervention operation of personnel, and the operation and maintenance cost is reduced. The system is suitable for newly designed systems in the construction period and is also suitable for transforming the original systems.
Description
Technical Field
The invention relates to the field of water treatment, in particular to a frequency follow-up control method for a lift pump of water treatment.
Background
The traditional control mode of the water treatment lift pump is generally divided into two modes of control with a variable frequency speed regulator and control without the variable frequency speed regulator.
The control mode of the non-variable frequency speed regulator basically controls the starting, stopping and quantity of the pumps by liquid level. For example, if the liquid level reaches a certain height, the first pump is started, and if the liquid level continues to rise, the second pump is started until the Nth pump. As the liquid level drops, the number of pumps started is reduced and all pumps are stopped when below the protection level. In this control mode, the number of the pumps is changed at intervals, or one pump is added or one pump is reduced. Therefore, the flow rate is changed, or a certain flow rate is increased or decreased, which causes the rear side control system to receive impact, and the stable operation of the system is affected.
Under the control mode of frequency conversion speed regulation, one or all of the pumps are frequency conversion speed regulation. Therefore, the flow of the pump can be continuously adjusted through variable frequency speed regulation so as to avoid impacting a following system. The control mode of the lifting pump with frequency conversion and speed regulation is divided into a single frequency converter control mode and a whole frequency converter control mode.
The single frequency converter control mode is that one frequency converter is used for adjusting the size of a part of flow, when the flow adjusting range of the frequency converter exceeds the rated flow of the pump, the pump is switched to a power frequency mode, and the frequency converter is used for adjusting the flow of the other pump. The method has the disadvantages of complicated control, complicated circuit and high cost. The impact of frequent switching of power frequency and frequency conversion on the power grid and the pump is also great.
All the frequency converters are controlled in a mode that all the pumps are provided with the frequency converters, and the rotating speed of the pumps is controlled through the frequency converters to adjust the flow rate. In the control mode, the operating frequency of each pump needs to be manually set, and then the number of the operating pumps is changed according to the requirements of the system, namely the number of the operating pumps is increased and decreased according to the height of the liquid level. There are several problems with this control approach:
1. each pump needs to be preset with a frequency, and the frequency needs to be changed according to experience and actual conditions, which is difficult to master and needs to be groped for a long time. And it is more difficult to follow the change in time when the amount of water changes.
2. Changing the number of pumps can also cause a flow surge that affects the subsequent system.
Regardless of the control with frequency conversion speed regulation and the control without frequency conversion speed regulation, the traditional control mode judges whether the pump to be added has faults in advance when the pumps are added and reduced, and switches the running pumps at regular time, so that the abrasion of each pump is uniform. This inevitably results in a complex system and increased cost.
In summary, there are various problems to be solved in the control method of the intrinsic lift pump.
Disclosure of Invention
The purpose of the invention is as follows: the frequency follow-up control method of the lift pump for water treatment can ensure that the requirement on the control of the water treatment pump is met by means of automatic control under the condition that a complex measuring instrument and an execution system are not needed, so that the operation and control system of the water pump becomes extremely simple and controllable. Meanwhile, the system can flexibly meet the requirements of various working conditions, fully exert the capacity of the existing water treatment facilities and improve the shock resistance of the system.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a frequency follow-up control method for lift pump of water treatment comprises the following steps
Step 1: all the lift pumps for water treatment are controlled by frequency conversion of a frequency converter, and a liquid level meter for continuously measuring the height of the liquid level is arranged in a water collecting well of the lift pumps;
step 2: the measured value of the liquid level meter is output to a frequency converter or a PLC, a control instrument or an industrial personal computer;
and step 3: setting the minimum output frequency of the corresponding frequency converter when the liquid level of the water collecting well is lower, setting the maximum output frequency of the corresponding frequency converter when the liquid level of the water collecting well is higher, and linearly changing the frequency of the frequency converter of the lift pump and the measurement value of the liquid level meter; the higher value of the water collecting well liquid level is called as a full frequency liquid level, and the full frequency liquid level is higher than the real highest liquid level of the water collecting well or lower than the real highest liquid level of the water collecting well;
and 4, step 4: controlling the frequency set value of the frequency converter according to the output value of the liquid level meter;
and 5: the water inlet flow is changed by adjusting the number of the started lifting pumps and the high-low set value corresponding to the full-frequency liquid level;
step 6: all the lift pumps automatically stop running below the protective liquid level of the lift pumps; and automatically starting the operation of the lift pump giving a starting command above the protective liquid level of the lift pump.
In the above method for controlling the frequency of the lift pump in water treatment, in step 1, all the lift pumps share one inverter control, or each pump uses a separate inverter control.
In the above method for controlling the frequency of the lift pump for water treatment in a follow-up manner, in step 1, the liquid level meter is an ultrasonic type, a static pressure type, a laser type, a sliding or rotating mechanism type liquid level meter.
In the above-mentioned lift pump frequency follow-up control method for water treatment, in step 6, in case of meeting the inflow rate, the redundant or backup or faulty lift pump is not activated.
The invention can adjust the flow by utilizing the frequency adjusting function of the frequency converter, automatically control the change of the liquid level of the water collecting well caused by the change of the flow of the water inlet pipe network, and continuously, timely and reliably realize the flow control function of the lift pump. The method of the invention requires few monitoring and execution devices, but is extremely easy to implement for automatic control. The operation process can be completely separated from the intervention operation of personnel, and the operation and maintenance cost is reduced. The system is suitable for newly designed systems in the construction period and is also suitable for transforming the original systems.
Detailed Description
A water treatment lift pump frequency follow-up control method comprises the following steps:
step 1: all lift pumps for water treatment are controlled by frequency conversion of a frequency converter, and a liquid level meter capable of continuously measuring the height of a liquid level is installed in a water collecting well of the lift pumps.
Step 2: the measured value of the liquid level meter is output to a frequency converter or a PLC, a control instrument or an industrial personal computer and other control systems.
And step 3: setting the minimum output frequency of the corresponding frequency converter when the liquid level of the water collecting well is lower, setting the maximum output frequency of the corresponding frequency converter when the liquid level of the water collecting well is higher, and linearly changing the frequency of the frequency converter of the lift pump and the measurement value of the liquid level meter; this higher value of the sump well level may also be referred to as a full frequency level. The full frequency liquid level may be higher than the highest liquid level of the real sump well or lower than the highest liquid level of the real sump well. The full frequency liquid level is set only for the requirement of adjusting the long-term water inlet flow. The larger this value, the less the inlet water flow.
And 4, step 4: the frequency set value of the frequency converter is controlled by the output value of the liquid level meter, so that the operating frequency of a single or all the lift pumps is changed.
And 5: the water inlet flow is changed by adjusting the number of the started lifting pumps and the high-low set value corresponding to the full-frequency liquid level.
Step 6: all the lift pumps automatically stop running below the protective liquid level of the lift pumps; and automatically starting the operation of the lift pump giving a starting command above the protective liquid level of the lift pump.
In step 1, all the lift pumps may share one frequency converter for control, or each pump may use a separate frequency converter for control.
In step 1, the liquid level meter may be an ultrasonic type, a static pressure type, a laser type, a sliding or rotating mechanism, or the like.
In step 6, when the inflow rate is satisfied, the redundant or standby lift pump may not be started, and the lift pump with the fault may not be started.
Example (b):
a lift pump system of a sewage treatment system comprises 3 lift pumps of 7.5kw, and the lowest liquid level protected by the lift pumps is 1.0 meter. Each frequency converter is provided with a frequency converter, and the frequency converters can be independently started and stopped. The three lift pumps share the ultrasonic liquid level meter of a water collecting well. The output of the liquid level meter is 4-20 milliampere signal, which is converted into 0-10 meter liquid level meter signal through conversion after being sent to the PLC. And the PLC outputs an analog quantity 4-20 milliampere signal to control the set frequency of the frequency converter after program calculation. The PLC is connected with the upper computer through configuration software, and various parameters are set through a human-computer interface of the upper computer.
Step 1: the liquid level corresponding to the lowest frequency of each lift pump is set to be 0.0 meter, and the full-frequency liquid level corresponding to the highest frequency of each frequency converter, namely 50 Hz, is set to be 8.0 meters. When the actual liquid level of the water collecting well is 6 meters, the operation set frequency of the lifting pump is 37.5 Hz.
Step 2: the liquid level of the pump is set to be 1.0 meter, and a lifting pump is started according to the requirement of the inflow.
And step 3: when the actual liquid level of the water collecting well is 7 meters, the operation set frequency of the lift pump is 43.75 Hz.
And 4, step 4: observing for a period of time, if the inflow water flow is sensed to be larger, the liquid level corresponding to the maximum frequency of 50 Hz of each frequency converter can be changed to 9.0 meters. When the actual liquid level of the water collecting well is 7 meters, the operation set frequency of the lifting pump is 38.8 Hz.
And 5: when the liquid level is lower than 0.9 m, the lift pump stops automatically. When the liquid level is higher than 1.0 m, the lift pump is automatically started.
Step 6: the lift pump can automatically find a balance point of frequency and liquid level after long-term operation, and basically stable water inlet is achieved.
The invention reasonably utilizes the continuous adjusting function of the water pump frequency converter and continuously controls and adjusts the liquid level of the water collecting well, so that the delivered water quantity is continuously changed without impact. Because the control variable is simpler, various monitoring and executing elements of the control system are fewer, and the operation and the control are greatly simplified.
Simultaneously, because the change volume of system is the liquid level of sump pit, this liquid level is positive correlation with the flow of inlet tube net, and when inlet tube net flow was big, the liquid level of sump pit was than higher, and the frequency of elevator pump is bigger, the corresponding increase of flow also. Otherwise, it is decreased. The process is automatically realized, is a follow-up process, and can be adjusted according to the liquid level value of the full-frequency liquid level. The system can timely and automatically adjust the frequency or the flow of the lift pump according to the change of the flow of the water inlet pipe network.
Meanwhile, the invention can properly reduce the design capacity of the regulating tank or cancel the sedimentation tank by utilizing the buffer function of the volume of the longer pipe network, thereby reducing the construction cost.
The water treatment lift pump of the method can meet the requirements of various water treatment industries, and has the advantages of simple control, stability, reliability, economy, impact resistance and wide application range.
In conclusion, the frequency adjusting function of the frequency converter can be utilized to adjust the flow, the automatic control can be realized according to the change of the liquid level of the water collecting well caused by the change of the flow of the water inlet pipe network, and the flow control function of the lift pump can be continuously, timely and reliably realized. The method of the invention requires few monitoring and execution devices, but is extremely easy to implement for automatic control. The operation process can be completely separated from the intervention operation of personnel, and the operation and maintenance cost is reduced. The system is suitable for newly designed systems in the construction period and is also suitable for transforming the original systems.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification, or any direct or indirect application attached to other related technical fields, are included in the scope of the present invention.
Claims (4)
1. A water treatment lift pump frequency follow-up control method is characterized in that: the method comprises the following steps:
step 1: all the lift pumps for water treatment are controlled by frequency conversion of a frequency converter, and a liquid level meter for continuously measuring the height of the liquid level is arranged in a water collecting well of the lift pumps;
step 2: the measured value of the liquid level meter is output to a frequency converter or a PLC, a control instrument or an industrial personal computer;
and step 3: setting the minimum output frequency of the corresponding frequency converter when the liquid level of the water collecting well is lower, setting the maximum output frequency of the corresponding frequency converter when the liquid level of the water collecting well is higher, and linearly changing the frequency of the frequency converter of the lift pump and the measurement value of the liquid level meter; the higher value of the water collecting well liquid level is called as a full frequency liquid level, and the full frequency liquid level is higher than the real highest liquid level of the water collecting well or lower than the real highest liquid level of the water collecting well;
and 4, step 4: controlling the frequency set value of the frequency converter according to the output value of the liquid level meter;
and 5: the water inlet flow is changed by adjusting the number of the started lifting pumps and the high-low set value corresponding to the full-frequency liquid level;
step 6: all the lift pumps automatically stop running below the protective liquid level of the lift pumps; and automatically starting the operation of the lift pump giving a starting command above the protective liquid level of the lift pump.
2. The lift pump frequency follow-up control method of water treatment according to claim 1, characterized in that: in step 1, all lift pumps share one inverter control, or each pump uses a separate inverter control.
3. The lift pump frequency follow-up control method of water treatment according to claim 1, characterized in that: in the step 1, the liquid level meter is an ultrasonic type, static pressure type, laser type, sliding or rotating mechanism type liquid level meter.
4. The lift pump frequency follow-up control method of water treatment according to claim 1, characterized in that: in said step 6, in case of a sufficient inflow, the redundant or backup or faulty lift pump is not activated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810351894.7A CN108547760B (en) | 2018-04-19 | 2018-04-19 | Frequency follow-up control method for lift pump of water treatment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810351894.7A CN108547760B (en) | 2018-04-19 | 2018-04-19 | Frequency follow-up control method for lift pump of water treatment |
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| Publication Number | Publication Date |
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| CN108547760A CN108547760A (en) | 2018-09-18 |
| CN108547760B true CN108547760B (en) | 2019-12-31 |
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| CN201810351894.7A Active CN108547760B (en) | 2018-04-19 | 2018-04-19 | Frequency follow-up control method for lift pump of water treatment |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112682300A (en) * | 2020-12-30 | 2021-04-20 | 上海远动科技有限公司 | Control method of variable-frequency lift pump based on liquid level regulation |
| CN114198293A (en) * | 2022-01-24 | 2022-03-18 | 高格立节能科技(海南)有限公司 | Variable frequency control method and controller of sewage lift pump |
| CN114810573B (en) * | 2022-04-29 | 2023-07-21 | 扬州大学 | Be used for water pump air suction rate survey device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09160654A (en) * | 1995-12-13 | 1997-06-20 | Nissin Electric Co Ltd | Method and device for water level control |
| CN101761490A (en) * | 2009-12-23 | 2010-06-30 | 北京吉源汇远科技有限公司 | Control method and system for inlet water lifting pumps of sewage plant |
| CN101922443A (en) * | 2009-06-15 | 2010-12-22 | 上海远动科技有限公司 | Control method of variable frequency lift pump based on liquid level adjustment |
| CN204941881U (en) * | 2015-08-07 | 2016-01-06 | 南京贝德环保设备制造有限公司 | A kind of constant pressure water supply automatical control system |
| CN107376456A (en) * | 2017-08-17 | 2017-11-24 | 桑德集团有限公司 | A kind of sewage disposal filtering cloth filtering pool autocontrol method |
-
2018
- 2018-04-19 CN CN201810351894.7A patent/CN108547760B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09160654A (en) * | 1995-12-13 | 1997-06-20 | Nissin Electric Co Ltd | Method and device for water level control |
| CN101922443A (en) * | 2009-06-15 | 2010-12-22 | 上海远动科技有限公司 | Control method of variable frequency lift pump based on liquid level adjustment |
| CN101761490A (en) * | 2009-12-23 | 2010-06-30 | 北京吉源汇远科技有限公司 | Control method and system for inlet water lifting pumps of sewage plant |
| CN204941881U (en) * | 2015-08-07 | 2016-01-06 | 南京贝德环保设备制造有限公司 | A kind of constant pressure water supply automatical control system |
| CN107376456A (en) * | 2017-08-17 | 2017-11-24 | 桑德集团有限公司 | A kind of sewage disposal filtering cloth filtering pool autocontrol method |
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