WO2002019049A2 - Time-based proportional control - Google Patents

Time-based proportional control Download PDF

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Publication number
WO2002019049A2
WO2002019049A2 PCT/US2001/026977 US0126977W WO0219049A2 WO 2002019049 A2 WO2002019049 A2 WO 2002019049A2 US 0126977 W US0126977 W US 0126977W WO 0219049 A2 WO0219049 A2 WO 0219049A2
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WO
WIPO (PCT)
Prior art keywords
setpoint
accordance
value
time
proportional control
Prior art date
Application number
PCT/US2001/026977
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French (fr)
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WO2002019049A3 (en
Inventor
Richard W. Ii Dennis
Original Assignee
United States Filter Corporation
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Publication date
Application filed by United States Filter Corporation filed Critical United States Filter Corporation
Priority to EP01968263A priority Critical patent/EP1314073A2/en
Priority to AU2001288521A priority patent/AU2001288521A1/en
Publication of WO2002019049A2 publication Critical patent/WO2002019049A2/en
Publication of WO2002019049A3 publication Critical patent/WO2002019049A3/en

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D21/00—Control of chemical or physico-chemical variables, e.g. pH value
    • G05D21/02—Control of chemical or physico-chemical variables, e.g. pH value characterised by the use of electric means

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Devices For Medical Bathing And Washing (AREA)
  • Orthopedics, Nursing, And Contraception (AREA)

Abstract

The instant invention is a method which includes the addition of a deviation compensation function effective to automatically adjust the offset used in time-based proportional control. Inclusion of this improvement finds particular utility in situations like public pools where daily bather load varies depending on weather and other unpredictable factors.

Description

Enhanced Time-Based Proportional Control
FIELD OF THE INVENTION This invention relates to time-based proportional control useful for chemical dosage control of water purification systems, such as the addition of chlorine to municipal swimming pools. The invention particularly relates to improvements in a time-based proportional control system for automating dosage control .
BACKGROUND OF THE INVENTION Virtually all chemical dosage controllers marketed by U.S. Filter/Stranco within the last 10-12 years for use in the aquatic and industrial/municipal markets include a form of proportional chemical dosage control commonly referred to as Time-Based Proportional Control. Time- based proportional control has demonstrated usefulness for applications in cooling towers and other recirculated or batch systems that may experience dramatic loading swings. Time-Based Proportional control was originally developed for use in spa applications where the chlorine demand will vary considerably due to small water volumes and the ratio of bodies/gallons of water in a spa. Standard on/off control for this application was inadequate, as the only adjustment was the chlorine feed rate. On/off only control suffers from overshooting in either low loading situations, or inability to reach setpoint in high loading situations. A common method of addressing said overshooting is to manually adjust feed rates upwardly during the day and downwardly at night . Time-Based Proportional control is basically a variation of on/off control which utilizes a relay output. Time-based proportional control utilizes a type of pulse width modulation effective to vary the duty cycle of the output relay on-time with respect to the deviation from setpoint . The duty cycle period is typically 30 seconds to one minute. As the sensor moves farther away from setpoint, the percentage of on-time per minute will increase. Conversely, the closer the sensor moves towards setpoint, the less the feeder operates per minute. Whenever the sensor of the controller exceeds setpoint, the feeder is always off. Recent improvements to this control have been the addition of an offset to keep the feeder from completely stopping until the setpoint is exceeded by some value and the ability to change the duty cycle period. A deficiency of the time-based proportional control function is that it fails to operate efficiently because it never reaches setpoint on high loading days-when it is needed the most . Thus, what is lacking in the art is an ability to incorporate a form of deviation compensation which could be described as time-based proportional control with automatic offset, to thus include a functionality, having a relatively small number of resets per minute and a low sensitivity which, when incorporated therein, would eliminate the systems failure to achieve setpoint on high loadings days .
SUMMARY OF THE INVENTION The instant invention is a device and method for its use which includes the addition of a type of deviation compensation function which, in effect, provides an automatic offset ability which is effective for automatically adjusting the offset used in time-based proportional control . In practice actual offset adjustment is not always necessary. An equivalent result is achievable by including a mathematical incrementation of the duty cycle ratio. Inclusion of this improvement finds particular utility in situations like public pools where daily bather load varies depending on weather and other unpredictable factors. Accordingly, it is an objective of the instant invention to teach a method and device to enhance time- based proportional dosing of chemical additives by inclusion of a form of deviation compensation effective to approximate an ideal proportional control response. It is a further objective of the invention to provide an ideal proportional control response by providing time based proportional control with automatic offset. It is yet another objective of the instant invention to provide an ideal proportional control response by mathematically incrementing the duty cycle ratio. It is a still further objective of the instant invention to provide ideal proportional control response by including integration of a measured signal . Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a graphical representation of prior art on/off control ; Figure 2 illustrates a typical on/off response curve; Figure 3 graphically illustrates chemical wastage; Figure 4 illustrates typical time-based proportional control; Figure 5, illustrates the ideal response of a Time Based Proportional control system; Figure 6 illustrates actual proportional control response with loading; Figure 7 shows the programmed response of the Time Based Proportional control with the addition of Integral response; Figure 8 is illustrative of the expected time-based proportional control with integral response in a typical HRR (High Resolution Redox) loading situation; Figures 9A through Figure 9C is an illustration of a feed up example utilizing timed base proportional logic; Figures 10A through Figure 10E modified the prior art proportional logic mode of operation by including integration of a measured signal .
DETAILED DESCRIPTION OF THE INVENTION Time-Based Proportional control devices, for example devices available from USFilter/Stranco under the name STRANTROL are an improvement of the On/Off control method. On/Off is commonly used for simple automatic process control . To explain the improvement Time Based Proportional control provides, it is best to first explain the On/ Off control method and its limitations-: Note that in Figures 1-8 the X-axis represents time and the Y-axis represents the stated value but is not unit dependent, e.g. for proportional band width (PB) , the graphical analysis is independent of whether the setpoint units are in mV, pH, microsiemens, or the like. Now referring to Figure 1, On/Off control, as the name implies, has only two control states, ON and OFF. A disinfection control system feeding a chemical like Sodium Hypochlorite can be used as a good example. When the measured signal (HRR) is below the desired value (setpoint) , the controller output is ON and stays on continuously until the measured signal meets or exceeds the setpoint. When the measured signal equals or exceeds the setpoint, the controller output changes to the OFF condition and the chemical feeder stops adding more chemical to the system. With respect to specific chemical feeders, the controlling limitation is the ability of the feed system to tolerate a power on duty cycle of fractions of a minute. High current rotational motor driven pumps can be damaged by short duty cycles such as 30 seconds on, 30 seconds off. Motor-operated ball valves also cannot tolerate short duty power applications. US Filter/Stranco utilizes Time-Based Proportional (TBP) control to regulate their patented CHF-150 Calcium Hypochlorite feeder, along with a variety of brands of solenoid-motor diaphragm metering pumps. It is likewise within the purview of the instant invention to utilize time based proportional control to regulate peristaltic pumps from various manufacturers, solenoid valves that control water flow to venturi-type ejectors used to feed gaseous and liquid chemicals into water such as Chlorine, Sulfur Dioxide, Carbon Dioxide, and the like. Additionally, the use of TBP to control special duty solenoid valves that operate under pressure or vacuum to control chemicals (liquid and gaseous) fed, for example,, to US Filter/Stranco' s patented WATER CHAMP gas induction feeders, C02 feeders and the like are also contemplated. As further illustrated in Figure 2, a typical on/off response curve is exemplified. The limitations of this control method are the system lag time and loading. In most industrial applications, ON/OFF control always overshoots the setpoint both on the increase and decrease of the measured signal. In the disinfection control example, when the HRR exceeds the setpoint, the chemical fed to the system stops, but the mixing and distribution of the chemical fed during the lag time continues to increase the system's HRR. This sinusoidal response is very typical for this control method. Restricting the flow rate of chemical to the system can minimize the sine wave amplitude, however during high load events the chemical feed will be unable to meet the demand. The result is that some overshoot is accepted as the limitation of an inexpensive (and simple) control method. As particularly illustrated in Figure 3, the height of the first peak will vary based upon the response time of the system, and the initial deviation from setpoint. The areas under the curve (above the setpoint) also represent wasted chemical. Now referring to Fig. 4, typically Time Based Proportional response improves upon the simple control method by adjusting the feed rate of chemical based upon the measured signal's deviation from setpoint. In Time Based Proportional control, the ON time per minute of the output relay is varied based upon the measured signal's distance from setpoint. This is very similar to the P of P. I. D. control, except the output is not continuous. The advantage can be seen using the same disinfection example. If one turns the Sodium Hypochlorite pump on for 10 seconds and off for 50 seconds when you are only 1 mV below the desired HRR, the rate of HRR rise will be far less per minute and the overshoot will be minimal . Figure 4 illustrates the output feed ratio of time based proportional control throughout the proportional band. The benefit of time based proportional control is a more consistent disinfection rate (less corrosion and fouling) , and chemical is conserved because chemical is not being fed to exceed the desired disinfection rate. With reference to Figure 5, the ideal response of a Time Based Proportional control system is illustrated. Proceeding to Figure 6, while Time Base Proportional control is an improvement over ON/OFF control, it still has certain limitations. With large fluctuations of loading, Time-based proportional control may not increase the output enough to compensate. Using the disinfection example again, when an increased loading condition occurs, the controller using Time Based Proportional control will proportion the output to increase the Sodium Hypochlorite feed rate to the system. But as the HRR starts to rise, the controller will reduce the output at the same ratio as the previous loading. The result is a setpoint that may never be achieved, because it now takes more Sodium Hypochlorite to maintain the same HRR (due to loading) . In order to address the inability of a time based proportional control system to achieve setpoint during a loaded condition, the instant invention incorporates an additional response into Time-based proportional control that will compare the measured signal to the setpoint with respect to time, and increase or decrease the output time ratio (duty cycle) to compensate for loading as needed. This is accomplished by increasing or decreasing an offset value applied to the control setpoint. Figure 7 depicts the programmed response of the Time Based Proportional control with the addition of selected time duration response. The rate of change would be tied proportionally to the deviation from setpoint and may be adjustable with software. The time base used for the selected time duration response would be different (usually longer) than the proportional time base, is generally set forth as a multiple thereof, and can also be adjustable. Typically, in the recirculated systems currently controlled by time based proportional control, the selected time duration response time base would about 5 minutes. Referring to Figure 8, the figure is illustrative of the expected time-based proportional control with selected time duration response in a typical HRR loading situation as described in the text above. As is readily appreciated, this curve closely mirrors the ideal proportional control response as set forth in Figure 5. Now referring to Figures 9A through Figure 9C and Figures 10A through Figure 10E, the inclusion of integration logic within the standard proportional logic feed up is exemplified. Figures 9A through Figure 9C is an illustration of a feed up example utilizing timed base proportional logic, absent selected time duration response logic. Figures 10A through Figure 10E, specifically the area within the block 1010, modifies the prior art proportional logic mode of operation by utilizing a form of deviation compensation, for example by including selected time duration response logic, which may be manifested as integration of a signal, so as to achieve an automatic offset of the time based proportional control function. The signal must first be verified to be residing within the chosen proportional band width, and it must be further confirmed that the signal is within a particular hysteresis value about the desired setpoint. If the signal is found to be outside of the hysteresis value of setpoint, then a determination must be made as to whether the signal falls within the category of being either steady or retreating from the setpoint during the integral time duration. If the determination is affirmative, then a change in the offset is carried out based upon selecting a value, herein termed the "offset sensitivity value" or OS and multiplying it by the value of deviation from setpoint. Inclusion of this subroutine idealizes the time based proportional response. Ranges of typical values for the calculation of the formulas are as follows: Proportional Band Width (PB) is typically 30 or 60 mV with an allowable range between about 5 and 500 mV. .50 pH units is typical with an adjustable range between about -10 and 5.00 pH units. From about 100 to 500 microsiemens is typical with an adjustable range between about 10 and 5000 microsiemens . Time Base (TB) : typically 30 or 60 seconds with an adjustable range between about 15 and 600 seconds Signal (SIG) : HRR typical range is 0-1000 mV with an instrument maximum range of -1500 to +1500, pH typical control range of 2-12 pH with an instrument maximum range of 0.00-14.00 pH. Conductivity typical range is 1000-5000 microsiemens with an instrument maximum range of 0-10,000 microsiemens. Setpoint (SP) : HRR is application dependent but is generally within the range of about 150 to 780. The pH will typically be between 2 and 12 pH with the greatest majority of applications (90%) within the 6.00-9.00 pH range. Conductivity setpoints are generally between 1000 and 4000 microsiemens. Hysteresis values for HRR are 0-1O mV with .02 typically used. Hysteresis for pH is typically .02 or .1 with a range of O.00- 1.0 pH. Conductivity hysteresis is usually 10 but can range from 0 - 1000. Offset Sensitivity Value (OS) is a percentage or fractional percentage with a range between 0 and 100%. The Setpoint Offset Value (SOV) is calculated by taking the Sustained Deviation From Setpoint (SD) as a fractional percentage of the Proportional Band (PB) multiplied by the Offset Sensitivity Value (OS) times the Proportional Band, according to the formula: SOV = (SD/PB) *OS*PB Example: SD= 10 mV; PB = 30 mV; % of PB =.33; if Offset Sensitivity Value = 1.00 then setpoint offset would change by .33 * OS * 30 or 10 mV. If OS=.5 then setpoint offset would be 5 mV. It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and drawings .

Claims

CLAIMS :
Claim 1. A process for time-based proportional control of chemical values in a water treatment system wherein a measured signal value is generated, comprising the steps: selecting an offset sensitivity value; and calculating a setpoint offset value (SOV) to determine said measured signal value; wherein said measured signal value approximates an ideal proportional control response.
Claim 2. A process in accordance with claim 1 wherein: said setpoint offset value is calculated according to the formula SOV = (SD/PB) * 'OS * PB where SD equal s the sust a ined deviat ion f rom setpoint PB equals Proportional Band Width OS equals Offset Sensitivity Value .
Claim 3 . In a process for time-based proportional control of chemical values in a water treatment system wherein a measured signal value is generated, the improvement comprising: modifying said measured signal value to be within a range defined by a particular proportional band width; verifying that said signal value lies within a hysteresis value about a particularly defined setpoint; measuring said signal value to confirm that said signal value is steady or retreating from said setpoint during a selected time duration ; selecting an offset sensitivity value; and calculating a setpoint offset value (SOV) according to the formula SOV = (SD/PB) * OS * PB where SD equals the sustained deviation from setpoint PB equals Proportional Band Width OS equals Offset Sensitivity Value;
wherein said measured signal value approximates an ideal proportional control response.
Claim 4. A process in accordance with claim 3 wherein: said particular proportional band width is between " about 5 and 500 mV.
Claim 5. A process in accordance with claim 3 wherein: said particular proportional band width is between about 0.1 and 5.0 pH units.
Claim 6. A process in accordance with claim 3 wherein: said particular proportional band width is between about 10 and 5000 microsiemens.
Claim 7. A process in accordance with claim 3 wherein: said time base is between about 15 and 600 seconds.
Claim 8. A process in accordance with claim 3 wherein: said selected time duration is a multiple of the time base.
Claim 9. A process in accordance with claim 3 wherein: said hysteresis value is between about 0 and 10 mV.
Claim 10. A process in accordance with claim 3 wherein: said hysteresis value is between about 0 and 1.0 pH units.
Claim 11. A process in accordance with claim 3 wherein: said particular proportional band width is between about 0 and 1000 microsiemens.
Claim 12. A process in accordance with claim 3 wherein: said setpoint is between about 150 and 780 mV.
Claim 13. A process in accordance with claim 3 wherein: said setpoint is between about 2 and 12 pH units.
Claim 14. A process in accordance, with claim 3 wherein: said setpoint is between about 1000 and 4000 microsiemens.
Claim 15. A process in accordance with claim 3 wherein: said offset sensitivity value is within the range of about 0 and 100 percent.
PCT/US2001/026977 2000-08-29 2001-08-29 Time-based proportional control WO2002019049A2 (en)

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EP01968263A EP1314073A2 (en) 2000-08-29 2001-08-29 Time-based proportional control
AU2001288521A AU2001288521A1 (en) 2000-08-29 2001-08-29 Time-based proportional control

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US09/650,456 2000-08-29
US09/650,456 US6716359B1 (en) 2000-08-29 2000-08-29 Enhanced time-based proportional control

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Families Citing this family (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7326340B2 (en) * 2003-03-05 2008-02-05 Siemens Water Technologies Holding Corp. System for controlling sulfide generation
US7285217B2 (en) 2003-12-02 2007-10-23 Siemens Water Technologies Corp. Removing odoriferous sulfides from wastewater
US20070241062A9 (en) * 2004-07-08 2007-10-18 Simpson Gregory D Synergistic composition and method for odor control
US7959780B2 (en) * 2004-07-26 2011-06-14 Emporia Capital Funding Llc Textured ion exchange membranes
US7390399B2 (en) * 2004-12-21 2008-06-24 Siemens Water Technologies Holding Corp. Water treatment control systems and methods of use
US20060169646A1 (en) * 2005-02-03 2006-08-03 Usfilter Corporation Method and system for treating water
US7780833B2 (en) 2005-07-26 2010-08-24 John Hawkins Electrochemical ion exchange with textured membranes and cartridge
US7905245B2 (en) 2005-09-30 2011-03-15 Siemens Water Technologies Corp. Dosing control system and method
US8562803B2 (en) 2005-10-06 2013-10-22 Pionetics Corporation Electrochemical ion exchange treatment of fluids
US10343939B2 (en) 2006-06-06 2019-07-09 Evoqua Water Technologies Llc Ultraviolet light activated oxidation process for the reduction of organic carbon in semiconductor process water
WO2007146671A2 (en) 2006-06-06 2007-12-21 Fluid Lines Ultaviolet light activated oxidation process for the reduction of organic carbon in semiconductor process water
US9725343B2 (en) 2007-04-03 2017-08-08 Evoqua Water Technologies Llc System and method for measuring and treating a liquid stream
US20080245737A1 (en) * 2007-04-03 2008-10-09 Siemens Water Technologies Corp. Method and system for providing ultrapure water
US8961798B2 (en) 2007-04-03 2015-02-24 Evoqua Water Technologies Llc Method for measuring a concentration of a compound in a liquid stream
US8753522B2 (en) 2007-04-03 2014-06-17 Evoqua Water Technologies Llc System for controlling introduction of a reducing agent to a liquid stream
US9365436B2 (en) 2007-04-03 2016-06-14 Evoqua Water Technologies Llc Method of irradiating a liquid
US8741155B2 (en) 2007-04-03 2014-06-03 Evoqua Water Technologies Llc Method and system for providing ultrapure water
US9365435B2 (en) 2007-04-03 2016-06-14 Evoqua Water Technologies Llc Actinic radiation reactor
US7799224B2 (en) * 2008-01-30 2010-09-21 Siemens Water Technologies Corp. Wastewater treatment methods
US8067917B2 (en) * 2008-04-08 2011-11-29 Liebert Corporation Hysteresis mitigation and control method
US8153010B2 (en) * 2009-01-12 2012-04-10 American Air Liquide, Inc. Method to inhibit scale formation in cooling circuits using carbon dioxide
US8591730B2 (en) 2009-07-30 2013-11-26 Siemens Pte. Ltd. Baffle plates for an ultraviolet reactor
US8430112B2 (en) 2010-07-13 2013-04-30 Siemens Industry, Inc. Slurry feed system and method
US8968646B2 (en) 2011-02-18 2015-03-03 Evoqua Water Technologies Llc Synergistic methods for odor control
EP2527301B1 (en) 2011-05-26 2016-04-27 Evoqua Water Technologies GmbH Method and arrangement for a water treatment
CA2918564C (en) 2015-01-21 2023-09-19 Evoqua Water Technologies Llc Advanced oxidation process for ex-situ groundwater remediation
US11161762B2 (en) 2015-01-21 2021-11-02 Evoqua Water Technologies Llc Advanced oxidation process for ex-situ groundwater remediation
JP5925371B1 (en) * 2015-09-18 2016-05-25 三菱日立パワーシステムズ株式会社 Water quality management device, water treatment system, water quality management method, and water treatment system optimization program
US10228359B2 (en) 2017-03-16 2019-03-12 Gecko Alliance Group Inc. Method, device and apparatus for monitoring halogen levels in a body of water

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3794817A (en) * 1972-10-31 1974-02-26 Foxboro Co Adaptive non-linear control system
US5262963A (en) * 1991-06-28 1993-11-16 Imc Fertilizer, Inc. Automatic control system for phosphoric acid plant
US5320748A (en) * 1993-09-02 1994-06-14 Dupuis Joseph A Acid dispensing system for a swimming pool

Family Cites Families (121)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2008684A (en) 1931-10-27 1935-07-23 Mixing Equipment Company Inc Emulsifying unit
US2249263A (en) 1937-09-20 1941-07-15 Laval Separator Co De Apparatus for treating oils
US2212260A (en) 1938-02-12 1940-08-20 Brothman Abraham Dispersion device and the like
US2268461A (en) 1940-11-06 1941-12-30 Jeffrey Mfg Co Apparatus for producing flocculation
US2556014A (en) 1948-04-23 1951-06-05 Jeffrey Mfg Co Water treating apparatus
US2686110A (en) 1951-02-15 1954-08-10 Standard Oil Dev Co Reactor
US2740696A (en) 1951-03-30 1956-04-03 Exxon Research Engineering Co Polymerization apparatus unit
US2651582A (en) 1952-12-22 1953-09-08 Cellulose Fibers Inc Method of making a cuprammonium cellulose solution
NL113908C (en) 1956-05-16
US3252689A (en) 1964-06-10 1966-05-24 Diamond Alkali Co Method and apparatus for mixing and distributing liquids
US3389970A (en) 1967-02-15 1968-06-25 Edward G. Scheibel Liquid-liquid extraction column having rotatable pumping impeller assemblies
US3536646A (en) 1967-03-13 1970-10-27 Dow Chemical Co Method for polymer dilution
OA03094A (en) 1968-07-11 1970-12-15 P P I South African Pulp And P Improvements to the delignification and bleaching of cellulose pulps with gaseous oxygen.
US3559959A (en) 1968-08-13 1971-02-02 Monsanto Co Impeller and mixer-settler apparatus
US3702298A (en) 1970-09-10 1972-11-07 Eco Sciences Inc Method of disinfecting with divalent and trivalent metal germicide
UST896051I4 (en) 1970-11-12 1972-03-28 Zjl fxx mss mss^h disperstbzg,osi for making microporous materials
US3747899A (en) 1971-08-16 1973-07-24 Monsanto Co Mixer
US3756570A (en) 1971-09-29 1973-09-04 W Buhner Apparatus for continuous dispersion and homogenization of predominantly viscous substances
US3852234A (en) 1972-02-28 1974-12-03 Nalco Chemical Co Process and apparatus for dissolving water soluble polymers and gums in water involving inversion of water-in-oil emulsions
US3965027A (en) 1974-03-11 1976-06-22 Calgon Corporation Scale inhibition and corrosion inhibition
US4016078A (en) 1975-03-06 1977-04-05 The Dow Chemical Company Header block for tubular membrane permeator modules
US4146676A (en) 1975-03-12 1979-03-27 Olin Corporation Granular calcium hypochlorite coated with a low melting inorganic salt by spray graining
DE2625149C3 (en) 1976-06-04 1981-01-08 Hoechst Ag, 6000 Frankfurt Process and device for the continuous production of vinyl chloride polymers in aqueous emulsion
US4217145A (en) 1977-01-12 1980-08-12 Gaddis Preston G Process for admixing polymer emulsions with water to produce highly viscous liquids
US4113688A (en) 1977-12-14 1978-09-12 Hercules Incorporated Process for rapidly dissolving gels of water-soluble polymers by extrusion, cutting and then slurrying under high shearing forces
JPS54109939A (en) 1978-02-15 1979-08-29 Mitsui Petrochem Ind Ltd Oxidation reactor for preparing aromatic carboxylic acid
US4171166A (en) 1978-06-26 1979-10-16 Morehouse Industries, Inc. Dispersing apparatus with grooved impeller
US4218147A (en) 1978-08-21 1980-08-19 Nalco Chemical Company Apparatus for diluting concentrated polymer solutions
US4234440A (en) 1979-01-02 1980-11-18 Basf Wyandotte Corporation Hydroxybenzoic acid as pH buffer and corrosion inhibitor for antifreeze containing organosilicone-silicate polymers
LU80951A1 (en) 1979-02-20 1979-06-18 Fospur Ltd PRODUCTION OF DANGEROUS CHEMICAL SUBSTANCES
US4233265A (en) 1979-07-25 1980-11-11 Olin Corporation Liquid polymer hydration
US4241016A (en) 1979-10-09 1980-12-23 Basf Wyandotte Corporation Hydroxybenzoic acid as pH buffer and corrosion inhibitor for antifreeze containing organosiloxane-silicate copolymers
US4300909A (en) 1980-08-22 1981-11-17 Krumhansl Mark U Process control
US4433701A (en) 1981-07-20 1984-02-28 Halliburton Company Polymer flood mixing apparatus and method
CA1178720A (en) 1981-12-16 1984-11-27 Walter Sencza Continuous polymer feed system for a waste water treatment plant
EP0084404B1 (en) 1982-01-05 1989-05-31 University Of Manchester Institute Of Science And Technology Corrosion monitoring
US4522502A (en) 1982-10-22 1985-06-11 Stran Corporation Mixing and feeding apparatus
US4581074A (en) 1983-02-03 1986-04-08 Mankina Nadezhda N Method for cleaning internal heat transfer surfaces of boiler tubes
US4550011A (en) 1983-07-01 1985-10-29 Mccollum Roy L Sample flow cell for automatic halogen and pH control for water reservoirs
US4913822A (en) 1983-10-26 1990-04-03 Betz Laboratories, Inc. Method for control of scale and inhibition of corrosion in cooling water systems
US4648043A (en) 1984-05-07 1987-03-03 Betz Laboratories, Inc. Computerized system for feeding chemicals into water treatment system
US4664528A (en) 1985-10-18 1987-05-12 Betz Laboratories, Inc. Apparatus for mixing water and emulsion polymer
US4701055A (en) 1986-02-07 1987-10-20 Fluid Dynamics, Inc. Mixing apparatus
GB8611518D0 (en) 1986-05-12 1986-06-18 Manchester Inst Science Tech Corrosion monitoring
US4752740A (en) 1986-05-19 1988-06-21 Steininger Jacques M Electronic water chemistry analysis device with linear bargraph readouts
US4778280A (en) 1986-06-25 1988-10-18 Stranco, Inc. Mixing apparatus
US4719252A (en) 1986-07-22 1988-01-12 Drew Chemical Co. Process and apparatus for forming polymeric solutions
US4747978A (en) 1986-08-07 1988-05-31 Ppg Industries, Inc. Calcium hypochlorite compositions
US5382367A (en) 1987-08-07 1995-01-17 Zinkan Enterprises Co. Method of treating cooling water systems
US5164429A (en) 1987-08-25 1992-11-17 Stranco, Inc. Polymer activation apparatus
US5061456A (en) 1987-08-25 1991-10-29 Stranco, Inc. Polymer activation apparatus
US5135968A (en) 1990-10-10 1992-08-04 Stranco, Ltd. Methods and apparatus for treating wastewater
US5316031A (en) 1987-08-25 1994-05-31 Brazelton Carl L Valve with independent control of discharge through plurality of orifices
US5018871A (en) 1989-07-19 1991-05-28 Stranco, Inc. Polymer dilution and activation apparatus
JPH01122903A (en) 1987-11-06 1989-05-16 Tosoh Corp Granular substance of calcium hypochlorite and production thereof
WO1989008728A1 (en) 1988-03-17 1989-09-21 Comalco Aluminium Limited Metallic surface protection
DE3851951T2 (en) 1988-03-31 1995-02-23 Orbisphere Lab Inc Wilmington Amperometric measurement method Amperometric measurement method.
GB8814222D0 (en) 1988-06-15 1988-07-20 Total Pool Chemicals Ltd Improvement in/relating to sanitation of swimming pool water
DE3914024A1 (en) 1989-04-28 1990-10-31 Bruno Bachhofer METHOD FOR TREATING WATER, IN PARTICULAR BATHING WATER
US5004549A (en) 1989-10-10 1991-04-02 Olin Corporation Method for inhibiting scale formation using calcium hypochlorite compositions
US5112521A (en) 1989-10-10 1992-05-12 Olin Corporation Calcium hypochlorite compositions containing phosphonobutane polycarboxylic acid salts
US4977292A (en) 1989-12-15 1990-12-11 W. R. Grace & Co.-Conn. 4-phosphonomethyl-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane N-oxide and water-soluble salts thereof
US5820823A (en) 1990-03-02 1998-10-13 Sievers Instruments, Inc. Method and apparatus for the measurement of dissolved carbon
US5000866A (en) 1990-03-26 1991-03-19 First Brands Corporation Antifreeze compositions containing alkane tetracarboxylic acid for use with hard water
CH681179A5 (en) 1990-04-24 1993-01-29 Ingold Messtechnik Ag
FR2672058B1 (en) 1991-01-24 1995-04-28 Univ Nancy COMPOSITION OF FERROUS METAL CORROSION INHIBITOR, PROCESS FOR PREPARING THE SAME, AND USE THEREOF.
IT1251524B (en) 1991-03-18 1995-05-16 Vincenzo Lagana METHOD FOR THE PASSIVATION OF METAL SURFACES AFFECTED BY CONDITIONS AND CORROSION PROMOTING AGENTS
US5213694A (en) 1992-04-08 1993-05-25 American Hydro Systems, Inc. Water treatment control system for treating cooling tower makeup water
ATE153319T1 (en) 1992-07-23 1997-06-15 Unilever Nv METHOD AND DEVICE FOR MONITORING MICROORGANISMS
EP0595582B1 (en) 1992-10-29 1996-04-17 THE BABCOCK & WILCOX COMPANY Passivation of metal tubes
US5422014A (en) 1993-03-18 1995-06-06 Allen; Ross R. Automatic chemical monitor and control system
DE4312417A1 (en) 1993-04-16 1994-10-20 Henkel Kgaa Method for increasing the corrosion resistance of stainless steel
US5332511A (en) 1993-06-25 1994-07-26 Olin Corporation Process of sanitizing swimming pools, spas and, hot tubs
US5972196A (en) 1995-06-07 1999-10-26 Lynntech, Inc. Electrochemical production of ozone and hydrogen peroxide
US5658467A (en) 1993-08-05 1997-08-19 Nalco Chemical Company Method and composition for inhibiting growth of microorganisms including peracetic acid and a non-oxidizing biocide
US5980758A (en) 1993-08-05 1999-11-09 Nalco Chemical Company Method and composition for inhibiting growth of microorganisms including peracetic acid and a non-oxidizing biocide
CA2129489C (en) 1993-08-05 2000-10-10 Judy G. Lazonby Method and composition for inhibiting growth of microorganisms including peracetic acid and a non-oxidizing biocide
US5785867A (en) 1993-08-05 1998-07-28 Nalco Chemical Company Method and composition for inhibiting growth of microorganisms including peracetic acid and a non-oxidizing biocide
US5306432A (en) 1993-08-09 1994-04-26 Great Lakes Biochemical Co., Inc. Water purification
GB2281742A (en) 1993-09-09 1995-03-15 Grace W R & Co Biocidal composition
US5575920A (en) 1994-03-11 1996-11-19 Betzdearborn Inc. Method of inhibiting scale and controlling corrosion in cooling water systems
WO1996030307A1 (en) 1995-03-30 1996-10-03 Bioquest Spa halogen generator
FR2742080B1 (en) 1995-12-07 1998-01-16 Lorraine Laminage AQUEOUS SOLUTION FOR TREATING STEEL SHEETS
JP3747504B2 (en) 1996-02-23 2006-02-22 栗田工業株式会社 Copper pitting corrosion prevention method
US5855791A (en) 1996-02-29 1999-01-05 Ashland Chemical Company Performance-based control system
US5683654A (en) 1996-03-22 1997-11-04 Nalco Chemical Co Process to manufacture stabilized alkali or alkaline earth metal hypobromite and uses thereof in water treatment to control microbial fouling
US5770039A (en) 1996-05-03 1998-06-23 Ecolab Inc. Method and apparatus for measuring and controlling active oxygen concentration in a bleach environment
US5820256A (en) 1996-05-30 1998-10-13 Stranco, Inc. Motorless mixer
US5895565A (en) 1996-10-04 1999-04-20 Santa Barbara Control Systems Integrated water treatment control system with probe failure detection
US5858246A (en) 1997-01-14 1999-01-12 Fountainhead Technologies, Inc. Method of water purification with oxides of chlorine
US5849985A (en) 1997-01-14 1998-12-15 Fmc Corporation Use of persulfate to destroy haloform
US5800732A (en) 1997-02-07 1998-09-01 Diversey Lever, Inc. All-in-one treatment agent for cooling water
US5858249A (en) 1997-02-21 1999-01-12 Higby; Loren P. Electrochemical insolubilization of anionic arsenic method and apparatus
US5783092A (en) 1997-03-18 1998-07-21 Bio-Lab, Inc. Water treatment method
US5888374A (en) 1997-05-08 1999-03-30 The University Of Chicago In-situ process for the monitoring of localized pitting corrosion
US5947596A (en) 1997-06-10 1999-09-07 U.S. Filter/Stranco Dry powder batch activation system
US5882526A (en) 1997-06-12 1999-03-16 Great Lakes Chemical Corporation Methods for treating regulated waters with low levels of oxidizing halogens and hydrogen peroxides
JP3398572B2 (en) 1997-07-11 2003-04-21 株式会社片山化学工業研究所 Failure prevention method for aluminum brass pipes serving as seawater flow paths
US6030842A (en) 1997-07-21 2000-02-29 Environmental Test Systems, Inc. Method, composition and device for the determination of free halogens in aqueous fluids
US5866013A (en) 1997-08-12 1999-02-02 Betzdearborn Inc. Method for inhibiting scale and controlling corrosion in cooling water systems
US6033302A (en) * 1997-11-07 2000-03-07 Siemens Building Technologies, Inc. Room pressure control apparatus having feedforward and feedback control and method
WO1999024369A2 (en) 1997-11-07 1999-05-20 Bioquest Llc Amperometric halogen control system
US5814233A (en) 1997-11-10 1998-09-29 Great Lakes Chemical Corporation Compositions and methods for treating water
US5985155A (en) 1997-11-14 1999-11-16 Autopilot Systems, Inc. Method and apparatus for automatic adjustment of halogen production in a water treatment system
US6015484A (en) 1997-11-26 2000-01-18 Gamry Instruments, Inc. Detection of pitting corrosion
CA2253679A1 (en) 1998-01-26 1999-07-26 Elf Atochem S.A. Stainless steel passivation in an organosulfonic acid medium
US6146538A (en) 1998-02-23 2000-11-14 United States Filter Corporation Method of inhibiting scale formation
US6120698A (en) 1998-05-15 2000-09-19 Advanced Water Technology, Inc. Balanced water purification composition
US6132593A (en) 1998-06-08 2000-10-17 Tan; Yong-Jun Method and apparatus for measuring localized corrosion and other heterogeneous electrochemical processes
IL125592A (en) 1998-07-30 2004-06-01 Argad Eyal Water Treat Technol Water treatment
US6045706A (en) 1998-08-19 2000-04-04 U.S. Filter/Stranco Calcium hypochlorite feeder
US6315950B1 (en) 1998-09-04 2001-11-13 Hach Company Controlling chlorination of wastewater and chloramination of drinking water
MXPA01005642A (en) 1998-12-10 2003-07-14 Baker Hughes Inc Electrochemical noise technique for corrosion.
US6068012A (en) 1998-12-29 2000-05-30 Ashland, Inc. Performance-based control system
US6159552A (en) 1999-01-14 2000-12-12 Rutgers, The State University Inorganic conversion coatings for ferrous substrate
US6143184A (en) 1999-03-02 2000-11-07 United States Filter Corporation Air and water purification using continuous breakpoint halogenation
US6409926B1 (en) 1999-03-02 2002-06-25 United States Filter Corporation Air and water purification using continuous breakpoint halogenation and peroxygenation
US6149819A (en) 1999-03-02 2000-11-21 United States Filter Corporation Air and water purification using continuous breakpoint halogenation and peroxygenation
US6535795B1 (en) * 1999-08-09 2003-03-18 Baker Hughes Incorporated Method for chemical addition utilizing adaptive optimization
US6419817B1 (en) 2000-06-22 2002-07-16 United States Filter Corporation Dynamic optimization of chemical additives in a water treatment system
CA2413888A1 (en) 2000-06-22 2001-12-27 United States Filter Corporation Corrosion control utilizing a hydrogen peroxide donor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3794817A (en) * 1972-10-31 1974-02-26 Foxboro Co Adaptive non-linear control system
US5262963A (en) * 1991-06-28 1993-11-16 Imc Fertilizer, Inc. Automatic control system for phosphoric acid plant
US5320748A (en) * 1993-09-02 1994-06-14 Dupuis Joseph A Acid dispensing system for a swimming pool

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1314073A2 *

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