US3643102A - Radiation-sensitive control for the concentration of a chemical - Google Patents

Radiation-sensitive control for the concentration of a chemical Download PDF

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Publication number
US3643102A
US3643102A US3643102DA US3643102A US 3643102 A US3643102 A US 3643102A US 3643102D A US3643102D A US 3643102DA US 3643102 A US3643102 A US 3643102A
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United States
Prior art keywords
disinfectant
concentration
indicator
controlling
chamber
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Expired - Lifetime
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English (en)
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Norman Craik Harper
John Henry Marshman
Henry Thomas Marshman
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Individual
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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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
    • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Definitions

  • the invention enables samples to be taken at regular intervals from a selected point, preferably a point downstream of a pump in a recirculating line for the water, where the concentration is likely to be as low as at any other point in the pool. Also the invention enables disinfectant to be injected in a controlled manner for example by continuously operating the injector which can be arranged to operate during one measuring cycle prior to the taking of the measurement in the next cycle.
  • the control is therefore conveniently an ON-OFF control in which disinfectant is added or not according as a measurement of a sample shows that the disinfectant concentration is low or not low.
  • One preferred method of measuring a sample is to inject a measured quantity of disinfectant indicator into a measured quantity of water constituting the sample.
  • the indicator may be one such as orthotolodyne which colors the water yellow with an intensity depending on the amount of chlorine present. This can be detected by shining light from a lamp through the water in the chamber on to a photoelectric cell, preferably a photovoltaic cell to obtain a high output signal which will be a measure of the amount of chlorine present. The signal can then be compared with a reference signal and be arranged to initiate operation of the injector or not depending on whether it indicates that the chlorine concentration is low or not.
  • This method uses the indicator economically because a small quantity of water can be used as the sample and the amount of indicator injected can be correspondingly low.
  • FIG. I is a diagrammatic elevation of a swimming pool having a chlorine control arrangement according to the invention.
  • FIG. 2 is an elevation showing the general arrangement of the chlorine sampling unit
  • FIG. 3 is a plan view of a sampling unit
  • FIG. 4 is a section on the line IV-IV in FIG. 3;
  • FIG. 5 is a section on the line V-V in FIG. 3;
  • FIG. 6 is a circuit diagram
  • FIGv 7 is a diagram of an alternative unit.
  • a swimming pool 11 has a pump I2 for continuously circulating water from a drain 13 through a filter 14 and back into the pool inlet 15.
  • a branch passage from the connection between the pump I2 and the inlet 15 as shown at 16 enables part of the water to be drawn off to a sampling unit 17, and after sampling, this drawn off water is allowed to run to waste. It will be seen that the sample is taken from just downstream of the pump 12 which is the point in the cycle where the chlorine level will be the lowest.
  • a signal from the sampling unit 17 is fed to a control circuit 18 which controls a servo-operated chlorine injector device 19 which can inject shots of chlorine either directly into the pool as shown at 21, or into the passage leading into the inlet 15 down stream of the sensing unit as shown at 22.
  • the sensing unit 17 is arranged to give an inject signal or not according as the chlorine level sensed is below or above 0.3 parts per million.
  • the unit is arranged to operate in continually recurring l5- minute cycles, and if the chlorine level is detected (near the beginning of the cycle) to be less than 0.3 parts per million.
  • the chlorine injector is switched on and held on for the remainer of the 15-minute cycle. Whether or not the injector will be switched on in the next cycle depends on the reading of the sampling unit when the next cycle commences.
  • the equipment is shown generally in FIG. 2.
  • the sampling unit 17 (shown in detail in FIGS. 3, 4 and 5) is mounted in an assembly which also includes an electrical supply and a transformer, a synchronous motor driving a cam shaft through a reduction gearbox at a speed of 4 revolutions per hour to determine the 15-minute cycle, a tank 26 containing a chlorine indicator liquid, orthotolodyne, and a printed circuit board 27 carrying components of an electronic circuit 18.
  • the board 27 can be removed for servicing and replaced.
  • the whole of the equipment shown in FIG. 2 is included in a glass fiber reinforced plastic case which also incorporates indicator switches and instruments.
  • the cam shaft can be rotated by hand for maintenance.
  • the sampling unit shown in FIGS. 3, 4 and 5 comprises essentially a glass block 31 having a metering chamber 32 through which the water bled off at 16 is passes through a ball valve 33, the sampling chamber 32 exhausting to waste at 34.
  • Water normally flows freely past the valve 33 and through the metering chamber 32 to keep it flushed, but when a cycle is to commence one of the cams 25 closes the valve 33 to keep the water static in the metering or viewing chamber 32, by means of a silicon rubber ball 35 being held down on its conical seat (FIG. 5).
  • the second cam then presses the plunger 37 of a chlorine indicator injector unit 30 so that a piston 39 supported on a p.t.f.e. diaphragm 41 displaces the indicator in the piston chamber 42 and forces it through a nonretum valve 43 of the bicycle tire kind having a radial opening in a metal shaft 44, which opening is normally covered by a rubber sleeve 45.
  • the mechanical action of the cam is sufficient to open this oneway valve 44-45.
  • the indicator is prevented from flowing back to the tank 26 by a light nonretum valve 46.
  • the piston 42 rises again after the cam has operated the plunger 37, due to the action of a spring 47, the light nonretum valve 46 can reopen to permit the chamber 42 to be recharged with indicator for a shot for the next cycle.
  • the piston chamber arrangement provides a precisely metered amount of indicator to be injected into the metered amount of water in the viewing chamber 32.
  • the cell 51 is of the photovoltaic type giving an output voltage dependent on the amount of light falling on the sensitive area.
  • the amount of light reaching the cell 51 through the blue filter will depend upon the yellowness of the liquid in the viewing chamber and this will in turn depend on the amount of chlorine in the water, since the indicator injected into the viewing chamber causes a yellowing of the chlorine with an intensity increasing with the amount present.
  • the lamp 49 is switched on by a cam when the indicator has been injected into the viewing chamber and the lamp remains on for about 20 seconds to enable a steady reading to be obtained.
  • the line from the pump 16 includes a restrictor 53 for preventing the pool from trying to empty itself to waste through the line 16.
  • the circuit diagram is shown in FIG. 6 and it will be seen that the mains supply 61 energizes the motor 24 and a neon indicator 62 and also the primary winding of the transformer 23.
  • One secondary winding of the transformer is a l-volt winding and is connected with the lamp 49 through a switch 60 operated by the first cam 25.
  • a second secondary winding 64 provides the supply to the photocell 51.
  • the photocell 51 is connected in series with a variable resistor 65, the two being in parallel with a potentiometer 66 connected across the photocell supply.
  • the variable resistor 65 and potentiometer 66 are adjusted so that the voltage between their wipers 67 and 68 will be zero for a chlorine level of 0.3 parts per million.
  • These wipers are connected to the respective bases of transistors 71 and 72 whose power supply is obtained conventionally from a fourth winding 73 on the transformer 23 through a switch 70 operated by the second cam.
  • the transistor 72 is normally biased ON while the transistor 71 is normally biased OFF.
  • the transistor 71 remains turned OFF, but as soon as the voltage at 68 becomes negative with respect to the voltage at 67 in response to a fall of the chlorine level below 0.3 parts per million, the transistor 71 is turned ON and its output signal is amplified through an amplifier shown generally at 73 to turn ON a silicon-controlled rectifier 74 connected in series with the coil 75 of an operating relay.
  • the relay coil When the relay coil is so energized its contact 76 closes to connect the mains to the servo unit for energizing the chlorine injector 19.
  • the transistor 71, its amplifier 73 and silicon-controlled rectifier 74 are duplicated as shown generally at 77 in FIG. 6
  • the cell 51 is a photovoltaic cell, the voltage change and resistance change in response to a change in the light level falling upon it act together so that a signal of reasonable magnitude can be obtained in response to a small change in brightness.
  • the response of the system will depend upon the conditions. For example, if there is a high bathing load, an injection of chlorine will be reflected more quickly in the sampling unit since the chlorine will be mixed more quickly. Again, the chlorine level will vary-at least near the surface-in response to the amount of sun falling on the surface of the water. What is important is that there should be free chlorine above the nominal 0.3 parts per million, and this is assured by sampling at the point of lowest intensity of chlorine.
  • FIG. 7 An alternative arrangement is shown in FIG. 7 in which similar components have been given the same reference numerals as in the other figures.
  • the chlorine indicator is injected into the tank 32 from the reservoir 26 by means of a peristaltic pump 82 driven by a motor 83 when this is switched on in a checking cycle.
  • the metered amount of indicator is thus injected into the tank 32 and because it is heavier than the water it is mixed by a mixing device consisting of a permanent magnet 84 extending along the bottom of the chamber 32 and vibrated by an electromagnetic device 85 energized during the measuring cycle.
  • the cyclic operation of the solenoid valve 81, peristaltic pump 82 and the electromagnet 85 are controlled by microswitches operated by cams generally shown at 86 driven by a motor 24 as described in relation to the first embodiment.
  • the water and indicator is eventually flushed out to waste when the next cycle commences.
  • the lamp and photocell arrangement is similar to that described in the first embodiment and they are positioned at opposite ends of the chamber 32.
  • each of the steps in the cycle is controlled by an electrical switch, operation of the switches being correctly timed in relation to each other by a motor.
  • a control for the disinfectant concentration in a swimming pool comprising; means for taking a sample of the water, a metering chamber for receiving said sample, a peristaltic pump for injecting a metered amount of indicator into the chamber, means within the chamber for stirring the contents of the chamber, electromagnetic means for operating said means for stirring, means for determining the color intensity of the sample and indicator after operation of said means for stirring, means for comparing a signal dependent on the color intensity with a reference signal, means for controlling a chlorine injector in dependence on the comparison, a motor, and cam-operated switches cyclically controlled by the motor for controlling the timed relationship between taking of the sample, injecting the indicator, and controlling the chlorine injector.
  • Apparatus for controlling the disinfectant infectant concentration in swimming pool water comprising;
  • the means for controlling said second means to inject a measured shot of disinfectant into said pool if the measured concentration of disinfectant is below a threshold concentration, and not to inject a shot if the said measured concentration is above the threshold concentration, the means for obtaining samples being inactive to take a successive sample until adelay time has elapsed since disinfectant was injected into the pool.
  • Apparatus for controlling disinfectant concentration as in claim 2 wherein said means for repetitively obtaining samplings includes means for flushing said means for receiving prior to each successive sample.
  • Apparatus for controlling disinfectant concentration as set forth in claim 2 further comprising means for discharging the measured amounts of sampled water and indicator to waste and not to the pool after measuring the disinfectant concentration.
  • Apparatus for controlling disinfectant concentration as set forth in claim 2 wherein said receiving means includes a stirrer and electromagnetic means for vibrating said stirrer to mix the water with the indicator prior to measuring.

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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)
  • Sampling And Sample Adjustment (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
US3643102D 1968-02-15 1969-02-10 Radiation-sensitive control for the concentration of a chemical Expired - Lifetime US3643102A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB753768A GB1245102A (en) 1968-02-15 1968-02-15 Automatic control of chemical concentration

Publications (1)

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US3643102A true US3643102A (en) 1972-02-15

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US3643102D Expired - Lifetime US3643102A (en) 1968-02-15 1969-02-10 Radiation-sensitive control for the concentration of a chemical

Country Status (7)

Country Link
US (1) US3643102A (de)
JP (1) JPS4828230B1 (de)
CH (1) CH508941A (de)
DE (1) DE1907486C3 (de)
ES (1) ES363675A1 (de)
FR (1) FR2001959A1 (de)
GB (1) GB1245102A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3776408A (en) * 1971-06-28 1973-12-04 Scott Paper Co Nursing unit
US3992109A (en) * 1973-03-15 1976-11-16 Calspan Corporation Cyclic colorimetry method and apparatus
US10191498B2 (en) * 2015-03-05 2019-01-29 Pentair Water Pool And Spa, Inc. Chemical controller system and method
US11610467B2 (en) 2020-10-08 2023-03-21 Ecolab Usa Inc. System and technique for detecting cleaning chemical usage to control cleaning efficacy

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016079A (en) * 1975-09-16 1977-04-05 Aquasol, Inc. Automatic chlorine and pH control apparatus for swimming pools
US4013039A (en) * 1976-09-02 1977-03-22 International Business Machines Corporation Wet processing PH control

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3776408A (en) * 1971-06-28 1973-12-04 Scott Paper Co Nursing unit
US3992109A (en) * 1973-03-15 1976-11-16 Calspan Corporation Cyclic colorimetry method and apparatus
US10191498B2 (en) * 2015-03-05 2019-01-29 Pentair Water Pool And Spa, Inc. Chemical controller system and method
US10990115B2 (en) 2015-03-05 2021-04-27 Pentair Water Pool And Spa, Inc. Chemical controller system and method
US11687103B2 (en) 2015-03-05 2023-06-27 Pentair Water Pool And Spa, Inc. Chemical controller system and method
US11610467B2 (en) 2020-10-08 2023-03-21 Ecolab Usa Inc. System and technique for detecting cleaning chemical usage to control cleaning efficacy

Also Published As

Publication number Publication date
FR2001959A1 (de) 1969-10-03
DE1907486C3 (de) 1979-11-22
DE1907486B2 (de) 1979-03-22
GB1245102A (en) 1971-09-08
DE1907486A1 (de) 1969-09-11
CH508941A (de) 1971-06-15
JPS4828230B1 (de) 1973-08-30
ES363675A1 (es) 1971-01-01

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