CN106365381A - Reflux pump control method in sewage treatment plant - Google Patents

Abstract

The invention discloses a reflux pump control method in a sewage treatment plant. The reflux pump control method comprises automatic outer reflux pump control and automatic inner reflux pump control, wherein during the automatic outer reflux pump control, the reflux pump refers to a variable frequency speed-regulation pump, and the operation can be independently performed locally by virtue of a local/remote selection switch or automatic/manual and start/stop buttons on an upper computer; and in an automatic computer control mode, start/stop of the reflux pump depends on the on/off state of the biological tank series as well as the liquid level of the biological tank. The sewage treatment effect is good.

Description

Sewage treatment plant's backflow method for controlling pump

Technical field

The invention belongs to environmental area, particularly to a kind of sewage treatment plant backflow method for controlling pump.

Background technology

The Chinese government began to focus on problem of environmental pollution in the last few years, after particularly proposing the strategy of sustainable development, government Protection and the improvement of environment is also noted that while rapid economic development.Environmental conservation oneself become one of sill state basic policy of China. From the point of view of environmental improvement in recent years, the environmental protection of China is theoretical, technical study and application are little with external gap, and gap is than larger It is environmental unit equipment and automatic control system.The present situation of wastewater treatment in China factory robot control system(RCS) is: all standby with automatic manually, from System and introduction develop simultaneously.The instrumentation major part that some sewage disposals are adopted is the poor offline instrument of accuracy and reliability Table, monitoring meanss are also to measure by after sampling, then go adjusting device running status according to measurement result.Therefore it is difficult to carry out soon Fast and effective on line real time control, often leads to the unstable of effluent quality.Biochemical processing procedure of sewage is typical non-thread Property, the complex large system of time-varying, uncertainty, large time delay, its modeling with control to control boundary be proposed severe challenge.Herein The control situation of sewage disposal process is summarized as follows: 1) simple due to controlling, traditional control method (conventional control, optimization Control, Self Adaptive Control) still it is widely used, but it is because that sewage disposal process variable is many, process has non-linear, close coupling The features such as, and various parameters there is also time variation, therefore is difficult to obtain reason based on the traditional control method of mathematical models The control effect thought；2) although Based Intelligent Control has become forward position and focus in the research and application of sewage disposal, both at home and abroad Still in the wide variety of primary stage.

Content of the invention

For the defect of prior art, the invention provides a kind of sewage treatment plant backflow method for controlling pump.

A kind of sewage treatment plant backflow method for controlling pump automatically controls and internal reflux it is characterised in that including external reflux pump Originally automatically control；

External reflux pump automatically controls: reflux pump is variable-frequency control pump, its operation can by field control case " just Ground/far control selecting switch, individually operated on the spot, or pass through " automatic/hand " on host computer, " starting/stopping " button is grasped Make；Under computer controlled automatic pattern, the start-stop of reflux pump depends on " run/stop " state of residing biological tank series, with And biology pit level, and motor speed is adjusted according to flow of inlet water；Under computer controlled automatic mode, confirm existing in operator Field manual operation equipment is normal and " on the spot/remote control " permutator is beaten to when far controlling position, on computers by residing biological tank The conversion of serial " automatic/hand " switch to automatic, completes automatically controlling of reflux pump by plc internal processes, control logic includes:

The state of biological tank series residing for judgement, if state is " RUN ", and biological pit level is higher than 3.0m, then start Reflux pump, and backflow pump discharge f is calculated according to formula below_ppux04, adjust motor speed sp_ppux04, the counting period (can for 1min Adjust)；

$f_{ppux04}=\frac{f_{ma004}}{{\mathrm{aer}}_{op}}\×1.2\×c_{spx04}$

${\mathrm{sp}}_{ppux04}=\frac{f_{ppux04}}{750}\×945$

Wherein: f_ppux04For 1 minute average flow of inlet water (m³/ h), aer_opFor the biological tank number of series run, c_spx04For Correction coefficient, is preset as 1.0, data is adjustable on plc.When calculating rotating speed higher than 950, take 950rpm；When value of calculation is less than When 700, take 700rpm.And report to the police on host computer；

If residing biological tank sequence of states is " standby ", or biological pit level is less than 3m, then stop reflux pump；

Internal reflux the automatic control of pump: internal reflux pump is variable-frequency control pump, its operation can by field control case " just Ground/far control selecting switch, individually operated on the spot, or pass through " automatic/hand " on host computer, " starting/stopping button " is grasped Make, under computer controlled automatic pattern, the start-stop of internal reflux pump depend on residing biological tank series " run/stop " state and Biological pit level, and motor speed is adjusted according to flow of inlet water.Under computer controlled automatic mode, confirm scene in operator Manual operation equipment is normal and " on the spot/remote control " permutator is beaten to when far controlling position, on computers by residing biological tank system Row " automatic/hand " switch conversion, to automatic, completes automatically controlling of internal reflux pump by plc internal processes.Control logic includes:

The state of biological tank series residing for judgement, if state is " RUN ", and biological pit level is higher than 3.0m, then start Internal reflux pump, and internal reflux pump discharge f is calculated according to formula below_ppux09, adjust motor speed sp_ppux09, the counting period be 1 point Clock (adjustable)；

$f_{ppux09}=\frac{f_{ma004}}{{\mathrm{aer}}_{op}}\×5.25\×c_{spx09}$

${\mathrm{sp}}_{ppux09}=\frac{f_{ppux09}}{3300}\×1465$

Wherein: f_ma004For 1 minute average flow of inlet water (m³/ h), aer_opFor the biological tank number of series that works, c_spx09It is strong Positive coefficient, is preset as 1.0, data is adjustable on plc.When calculating rotating speed higher than 1676, take 1676rpm；When value of calculation is less than When 1059, take 1059rpm.And report to the police on host computer；

If residing biological tank sequence of states is " standby ", or biological pit level is less than 3.0m, then stop internal reflux pump.

The invention has the beneficial effects as follows: the system is a set of perfect control integration system.This control system has height Degree automatization level, controls Parameters variation, it has wide practical use at home well.

Brief description

The flow chart of Tu1Shi sewage treatment plant of the present invention sewage disposal；

Fig. 2 a is the flow chart that single biological tank runs；

Fig. 2 b is the flow chart that single series stops；

Fig. 2 c is the flow chart that biological tank series comprehensive runs.

Specific embodiment

Understandable for enabling the above objects, features and advantages of the present invention to become apparent from, below in conjunction with the accompanying drawings to the present invention Specific embodiment be described in detail, so that above and other purpose, feature and the advantage of the present invention will be become apparent from.Complete Identical reference instruction identical part in portion's accompanying drawing.Not deliberately accompanying drawing drawn to scale, it is preferred that emphasis is illustrate this Bright purport.

First the waste water processes of the present invention are introduced, refer to Fig. 1, the sewage in sewage treatment plant basin passes through Back with water inlet line accesses the sump of lift pump room, and by between 2 grids equipped with 8mm coarse rack, here intercepts larger in sewage Enter sewage pump room after impurity, flow into aerated grit chamber after sewage lifting and remove sand grains, be divided into 2 systems since then backward: One system 60,000 m³The sewage of/d, after 1mm fine fack, by biological tank, subsequently into mbr membrane biological reaction pond, removes The pollutant such as cod, bod5, n, p, wherein 50,000 m³The water outlet of/d, after uv sterilization, flows into mbr clear water reserviors, before entering clear water reserviors Add chlorine dioxide, to ensure that the chlorine residue in pipe network requires.Deliver to reclaimed wastewater reuse pipe outside factory finally by the lifting of water distribution pump house Net supplies water to user.Other 10,000 m³The mbr membrane biological reaction pond water outlet of/d, after uv sterilization, enters ro counter-infiltration system and carries out Advanced treating, subsequently into ro clear water reserviors, delivers to high-quality waterpipe outside factory finally by water distribution pump house and supplies water.Another system 4 Ten thousand m³The sewage of/d, after 3mm fine fack, by effusion meter metering water quantity, then passes through anaerobic/anoxic pond, enters Aeration tank, go Except pollutant such as cod, bod5, n, p, add chemical dephosphorization medicament according to water outlet situation, after through sedimentation tank precipitate and separate, water outlet converges Enter treatment plant's water-break main, after uv sterilization, through bar formula measuring tank metering water quantity, be ultimately discharged into river course.Two systems surplus Remaining mud all delivers to mud storage pool, after being processed by the dewaterer with pre-concentration function, then carries out harmlessness disposing.Different using two sets Processing system sewage is respectively processed, that is, reduce the cost of sewage disposal, the process of different qualities can be generated again Water, the sewage after process can do different purposes according to the difference of quality.

Need automatically controlling of following part: (1) water inlet the automatic control of pump in sewage disposal, automatically controlled according to collecting-tank The startup of intake pump processed and the number of units of water inlet pump startup, limit the number of starts in separate unit water pump certain time, accumulation water simultaneously The pump operation time, the boot sequence of water pump was arranged from small to large by the automatic water pump operation time, during stopping sequentially in contrast. The automatic alternate of achievable water pump is it is ensured that water pump is always at optimal operational condition.When dry running protection water level switch action, All water pumps are out of service.(2) thick, fine fack automatically controls, and the operation of grid to be automatically controlled by liquid level difference before and after grid, when After interval exceedes certain time, switch to time control.The boot sequence of system is: first starts auger conveyor, Ran Houqi Dynamic grid, during stopping, first freeze-frame grid, stop auger conveyor after grid all discharges into slag bucket again.Water-head setting value, grid Run time and cycle of operation adjustable.(3) aerated grit chamber automatically controls, and controls removing of aerated grit chamber according to temporal sequence The operation of sand machine and the operation (continuously being supplied by the air compressor machine on sand removing machine) of air-lift device, grit water separator is joined with sand removing machine Lock, completes the girt-water separation after air stripping.Aeration tank dissolved oxygen automatically controls, setting dissolved oxygen analytic instrument, each air in Aeration tank On arm, the gas flowmeter of setting, automatically adjusts the aperture of Aeration tank air inlet adjustment valve according to dissolved oxygen setting value in Aeration tank To keep dissolved oxygen in required set point.(4) sludge reflux amount automatically controls, according to the inflow of Aeration tank, from The operating number of dynamic control loop sludge pump by the flow of Frequency Converter Control return sludge pump, is realized inflow and is returned with mud The rational proportion of flow it is ensured that in Aeration tank biological treatment steady quality.(5) sludge concentration and dewatering system automatically controls, dirty Mud thickening machine controls and includes that necessary order is chain and programming in logic controls, and (mud chipper, enters mud with auxiliary equipment Pump, flocculant prepare dosing system, mud cake conveyer, flushing water pump etc.) coordinated signals." step " operation can be realized. (6) mbr membrane biological reaction pond automatically controls: setting dissolved oxygen analytic instrument in biological reaction pool, and Aeration tank each air arm sets Put gas flowmeter, the aperture of Aeration tank intake valve is automatically adjusted to keep dissolved oxygen being wanted according to dissolved oxygen setting value in pond In the set point asked.Liquidometer is set in pond simultaneously, in order to monitor the fluctuating liquid level in pond, and the suction pump connection with membranous system Lock control.Membranous system is according to the aquifer yield of system water flow-control membranous system.Membrane cisterna liquid level is also entered with frequency conversion suction pump simultaneously Row interlocked control, makes film surface be exposed in the air so that the liquid level that prevents membrane cisterna is too low.Film recoil and Chemical cleaning automatically control: Automatically control backwashing period and the chemical flush cycle of membrane component according to temporal sequence.(7) ro system automatically controls: ro system According to the ruuning situation of ro clear water pit level and distribution pump, control the aquifer yield of membranous system.(8) chlorination automatically controls: according to Water ratio flow control chlorine dosage, and water outlet chlorine residue is measured.(9) water distribution the automatic control of pump, according to water distribution water pump outlet pipe The road i.e. pressure set points of the middle water distribution system of water supply automatically adjust number of units and the rotating speed of distribution pump, permanent with the pressure of grid in ensureing Fixed.(10) power monitoring, to whole engineering construction power monitoring.Built-in power monitoring program, shows the main electricity of power system Parameter such as on off state, electric current, voltage, power, electric degree etc., realize monitoring, manage the power consumption of this engineering.(11) electrically set Standby control, motor can by automatically/control on the spot or remote manual control in the way of operate.Mode selects to pass through electric at each --- stop --- automatic selector switch to select on equipment control case/cabinet on the spot.Under mode on the spot, electrical equipment operating is not subject to Robot control system(RCS) controls；Under automated manner, electrical equipment is automatically controlled by affiliated field control station；Under soft manual mode, electricity Gas equipment carries out soft manual operation by operator in monitoring station.Major control mode includes, manual mode: by local control box Or the start stop operation to equipment for the button realization on mcc.Soft manual mode: i.e. remote manual control mode.Operator pass through The monitored picture of operation terminal or active station controls field apparatus with Genius mouse or keyboard.Automated manner: the operation of equipment is complete Full the on off control to equipment is completed according to the operating mode of sewage treatment plant and technological parameter by each plc, without manually doing In advance.The control hierarchy of three kinds of modes is from high to low: Non-follow control, soft Non-follow control, automatically controls.

Counted by remote input output unit (ri/o), field control station (lcs), CSRC work station (ccs) and factory Calculate the full factory robot control system(RCS) that machine management system (cms) forms.It is to be system network with fiber optic Ethernet, optical fiber industry Ethernet Network, is equipped with high-performance, highly reliable plc control station, and has the control system of the latest generation of server capability.System by with Under several parts composition:

Computer management system (mcs), computer management system is by director's office computer, chief engineer room computer, laboratory Computer and projector demonstrating computer etc. form, and four computers are connected with 100,000,000 grades of Ethernets, are equipped with printer, ups not The equipment such as uninterruptible power, projector.It is mainly used in completing the management to factory, scheduling and function for monitoring.Arrange one in meeting room Platform high-definition large-screen digital projection instrument.Projector full plant process flow capable of enlarged displaying, capital equipment operational factor and institute The data of the whole monitoring computer acquisitions needing.It is management personnel and start-up's real-time, detailed production process data of offer. By Ethernet switch, the Ethernet system of office is connected with the Ethernet system of total electric substation Central Control Room, reaches data The functions such as shared, supervision.

CSRC work station (ccs), is arranged on CSRC work station in the Central Control Room of main sub-station by two sets each other Hot standby monitoring computer, server, printer, ups uninterrupted power source, Ethernet switch and portable programmed computer etc. Composition.It is online that it is mainly used in completing the management to factory, scheduling, centralized operation, supervision, systemic-function configuration, control parameter Modification and setting, record, report generation and the function such as printing, fault alarm and printing.Can intuitively be shown by liquid crystal display The real-time working condition of Shi Quan factory each technological process section, the trend picture of each technological parameter, make operator grasp full factory in time and run Situation.Two sets of computers are hot standby each other.It is additionally provided with a set of dlp optical projection system in Central Control Room.This system mainly by projecting cell, Tiled display controller, central control system, hard-disc storage, matrix switcher and giant-screen application control software etc. form.Greatly Screen prjection system is connected with Central Control Room monitoring computer, can be shown on giant-screen for information about.By matrix switcher Also the video signal of industrial tv monitoring system can be accessed optical projection system to show on giant-screen, 12 road videos can be shown simultaneously Monitored picture.Computer digit and analogue signal can be shown with arbitrary size windowing optional position on giant-screen, windowing Quantity is unrestricted.

Field control station (lcs), by Siemens's plc-400 programmable controller, distributed i/o unit and associated satellite Equipment forms.Configurable industrial level Network Interface Module, fieldbus interface module, serial data communication (rs- as needed 232/485) interface module, and install Siemens's touch screen at the scene in control station, completes some at the scene and simply grasps to facilitate Make.

Network system, standard fiber Ethernet: responsible complex building computer management system and the monitoring of total transformer room Central Control Room Data communication between work station.Industrial optical fiber Ethernet: responsible Central Control Room monitor workstation and each field control station plc controller Between data communication.Field high-speed data communication network: using profibus-dp network, responsible plc controller main website and slave station And the data communication between plc and remote distributed i/o.

Full factory robot control system(RCS) (1) can in real time, continuously record important parameter.To important technical parameter in sewage disposal process As in dissolved oxygen (do) concentration in irrigation channel ph value, biological tank, biological tank, suspended sediment concentration etc. carries out real-time, continuous note Record, and the inquiry of historical data can be carried out.(2) automatically process alarm signal.When scene occur report to the police when, in real time display and Jingle bell, and display and writing function are provided；For great alarm signal (as ultralow in motor stall, liquid level or superelevation etc.), Computer capacity automatically sends control instruction and ensures system safety operation and record.(3) automatic report generation.Each plc in system Operation conditions often can show, each serial operation conditions of each order of classes or grades at school is aobvious in form in real time every other hour in real time in form Show, and can format print on request.

Separately below each automatic control section is described in further detail.

(1) biological tank automatically controls.Sewage treatment plant is provided with four series of biologic ponds altogether, in computer controlled automatic mould Under formula, job family columns depends on flow of inlet water, and corresponding relation see table:

Table 1 needs work biological tank series number

The control of each series is described as follows: under computer controlled automatic mode, operator confirm institute in certain series There is the manual normal operation of control device and " on the spot/remote control " permutator is beaten to when far controlling position, on computers by this series The conversion of " automatic/hand " switch to automatic, then it is all in series that " ready " equipment enters " " control models automatically.Hereafter each list Solely equipment can switch to " manual " pattern, and handoff procedure does not affect the current operating conditions of residing series.When all in series When equipment is " automatic " pattern, this sequence of states is shown as " ready ".Control process is as shown in Fig. 2 a, 2b, 2c:

Every 10 minutes (interval is adjustable), judge the serial number needing to run according to table 1；If desired the quantity run is big In " ready " number of series, then " ready " series is all put into operation and produce on host computer and report to the police.If desired run system Number of columns is less than " ready " series, then unnecessary series is set to " standby ".

If raw water flow signals collecting is less than biological tank series maintains the original state, and produces warning on host computer.

For ensureing the balanced operation time of each series, " ready " series will " RUN " and " standby " in turn, the time in turn It is set to 2 hours (adjustable).

When needing to reduce work number of series, from last time " standby ", stream time series the longest will select afterwards As " standby " series；

When needing to increase work number of series, this " standby " time the longest series will be put into operation.

If having device fails in certain work series, alarm signal will be produced on host computer, faulty equipment is by certainly Dynamic isolation, remaining equipment keeps former running status to change until chain condition.Operator may determine whether to terminate this series Run；

After fault-signal disappears, through operator's accreditation, (on-site manual normally adopts computer Non-follow control afterwards Mode normal operation), equipment is set to " automatic ", comes back in series.

(2) external reflux pump automatically controls, and reflux pump is variable-frequency control pump, and its operation can be by field control case " on the spot/and far control selecting switch, individually operated on the spot, or pass through " automatic/hand " on host computer, " starting/stopping " button Push-botton operation.Under computer controlled automatic pattern, the start-stop of reflux pump depends on " run/stop " shape of residing biological tank series State, and biological pit level, and motor speed is adjusted according to flow of inlet water.Under computer controlled automatic mode, in operator Confirm that on-site manual runs equipment normal and when " on the spot/remote control " permutator is beaten to remote control position, on computers will be residing Biological tank series " automatic/hand " switch conversion, to automatic, completes automatically controlling of reflux pump by plc internal processes.Control is patrolled Collect and include:

The state of biological tank series residing for judgement, if state is " RUN ", and biological pit level is higher than 3.0m, then start Reflux pump, and backflow pump discharge f is calculated according to formula below_ppux04, adjust motor speed sp_ppux04, the counting period (can for 1min Adjust).

$f_{ppux04}=\frac{f_{ma004}}{{\mathrm{aer}}_{op}}\×1.2\×c_{spx04}$

${\mathrm{sp}}_{ppux04}=\frac{f_{ppux04}}{750}\×945$

Wherein: f_ppux04For 1 minute average flow of inlet water (m³/ h), aer_opFor the biological tank number of series run, c_spx04For Correction coefficient, is preset as 1.0, data is adjustable on plc.When calculating rotating speed higher than 950, take 950rpm；When value of calculation is less than When 700, take 700rpm.And report to the police on host computer.

If residing biological tank sequence of states is " standby ", or biological pit level is less than 3m, then stop reflux pump.

(3) internal reflux the automatic control of pump.Internal reflux pump is variable-frequency control pump, and its operation can be by field control case " on the spot/and far control selecting switch, individually operated on the spot, or pass through " automatic/hand " on host computer, " starting/stopping " button Push-botton operation.Under computer controlled automatic pattern, the start-stop of internal reflux pump depends on " run/stop " of residing biological tank series State and biological pit level, and motor speed is adjusted according to flow of inlet water.Under computer controlled automatic mode, true in operator Recognize on-site manual operation equipment normally and " on the spot/remote control " permutator is beaten to when far controlling position, on computers by residing life Thing pond series " automatic/hand " switch conversion, to automatic, completes automatically controlling of internal reflux pump by plc internal processes.Control is patrolled Collect and include:

The state of biological tank series residing for judgement, if state is " RUN ", and biological pit level is higher than 3.0m, then start Internal reflux pump, and internal reflux pump discharge f is calculated according to formula below_ppux09, adjust motor speed sp_ppux09, the counting period be 1 point Clock (adjustable).

$f_{ppux09}=\frac{f_{ma004}}{{\mathrm{aer}}_{op}}\×5.25\×c_{spx09}$

${\mathrm{sp}}_{ppux09}=\frac{f_{ppux09}}{3300}\×1465$

Wherein: f_ma004For 1 minute average flow of inlet water (m³/ h), aer_opFor the biological tank number of series that works, c_spx09It is strong Positive coefficient, is preset as 1.0, data is adjustable on plc.When calculating rotating speed higher than 1676, take 1676rpm；When value of calculation is less than When 1059, take 1059rpm.And report to the police on host computer.

If residing biological tank sequence of states is " standby ", or biological pit level is less than 3.0m, then stop internal reflux pump.

(4) submersible agitator.Under computer controlled automatic pattern, the start-stop of submersible agitator depends on residing biological tank system The liquid level of row.For the submersible agitator of variation zone, it runs premise is that variation zone is chosen as " anoxic zone " by operator.? Operator's confirmation on-site manual operation equipment is normal and " on the spot/remote control " permutator is beaten to when far controlling position, in computer On by residing biological tank series " automatic/hand " switch conversion to automatic, by plc internal processes, according to biological tank level condition Start (>3.0m)/stop (<3.0m) submersible agitator.Agitator to variation zone, it automatically controls premise is that variation zone is grasped Making personnel selection is " anoxic zone ", otherwise keeps halted state.

Elaborate a lot of details in order to fully understand the present invention in the above description.But above description is only Presently preferred embodiments of the present invention, the present invention can be much to implement different from alternate manner described here, therefore originally Invention is not embodied as being limited by disclosed above.Any those skilled in the art are without departing from the technology of the present invention simultaneously In the case of aspects, all can be utilized the methods and techniques content of the disclosure above that technical solution of the present invention is made many possible Change and modify, or the Equivalent embodiments being revised as equivalent variations.Every content without departing from technical solution of the present invention, according to this The technical spirit of invention, to any simple modification made for any of the above embodiments, equivalent variations and modification, all still falls within skill of the present invention In the range of the protection of art scheme.

Claims (1)

1. a kind of sewage treatment plant backflow method for controlling pump automatically controls with internal reflux originally it is characterised in that including external reflux pump Automatically control；

External reflux pump automatically controls: reflux pump is variable-frequency control pump, its operation can by field control case " on the spot/remote Control selecting switch, individually operated on the spot, or pass through " automatic/hand " on host computer, " starting/stopping " push-botton operation；Meter Under calculation machine automatic control mode, the start-stop of reflux pump depends on " run/stop " state of residing biological tank series, and biological Pit level, and motor speed is adjusted according to flow of inlet water；Under computer controlled automatic mode, confirm on-site manual in operator Operation equipment is normal and when " on the spot/remote control " permutator is beaten to remote control position, on computers by residing biological tank series " from Dynamic/manually " switch conversion to automatic, completes automatically controlling of reflux pump by plc internal processes, control logic includes:

The state of biological tank series residing for judgement, if state is " RUN ", and biological pit level is higher than 3.0m, then start backflow Pump, and backflow pump discharge f is calculated according to formula below_ppux04, adjust motor speed sp_ppux04, the counting period is 1min (adjustable)；

$f_{ppux04}=\frac{f_{ma004}}{{\mathrm{aer}}_{op}}\&times;1.2\&times;c_{spx04}$

${\mathrm{sp}}_{ppux04}=\frac{f_{ppux04}}{750}\&times;945$

Wherein: f_ppux04For 1 minute average flow of inlet water (m³/ h), aer_opFor the biological tank number of series run, c_spx04For correction Coefficient, is preset as 1.0, data is adjustable on plc.When calculating rotating speed higher than 950, take 950rpm；When value of calculation is less than 700 When, take 700rpm.And report to the police on host computer；

If residing biological tank sequence of states is " standby ", or biological pit level is less than 3m, then stop reflux pump；

Internal reflux the automatic control of pump: internal reflux pump is variable-frequency control pump, its operation can by field control case " on the spot/ Remote control selecting switch, individually operated on the spot, or pass through " automatic/hand " on host computer, " starting/stopping button " operates, Under computer controlled automatic pattern, the start-stop of internal reflux pump depends on " run/stop " state and the life of residing biological tank series Thing pit level, and motor speed is adjusted according to flow of inlet water.Under computer controlled automatic mode, confirm live handss in operator Dynamic operation equipment is normal and " on the spot/remote control " permutator is beaten to when far controlling position, on computers by residing biological tank series The conversion of " automatic/hand " switch, to automatic, completes automatically controlling of internal reflux pump by plc internal processes.Control logic includes:

The state of biological tank series residing for judgement, if state is " RUN ", and biological pit level is higher than 3.0m, then return in startup Stream pump, and internal reflux pump discharge f is calculated according to formula below_ppux09, adjust motor speed sp_ppux09, the counting period is 1 minute (adjustable)；

$f_{ppux09}=\frac{f_{ma004}}{{\mathrm{aer}}_{op}}\&times;5.25\&times;c_{spx09}$

${\mathrm{sp}}_{ppux09}=\frac{f_{ppux09}}{3300}\&times;1465$

Wherein: f_ma004For 1 minute average flow of inlet water (m³/ h), aer_opFor the biological tank number of series that works, c_spx09For correcting system Number, is preset as 1.0, data is adjustable on plc.When calculating rotating speed higher than 1676, take 1676rpm；When value of calculation is less than 1059 When, take 1059rpm.And report to the police on host computer；

If residing biological tank sequence of states is " standby ", or biological pit level is less than 3.0m, then stop internal reflux pump.