EP0287761A2 - Vorrichtung und Verfahren zum Neutralisieren von oxidierenden Mitteln in einer Waschmaschine - Google Patents

Vorrichtung und Verfahren zum Neutralisieren von oxidierenden Mitteln in einer Waschmaschine Download PDF

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Publication number
EP0287761A2
EP0287761A2 EP88102045A EP88102045A EP0287761A2 EP 0287761 A2 EP0287761 A2 EP 0287761A2 EP 88102045 A EP88102045 A EP 88102045A EP 88102045 A EP88102045 A EP 88102045A EP 0287761 A2 EP0287761 A2 EP 0287761A2
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EP
European Patent Office
Prior art keywords
bath
agent
oxidizing agent
neutralizing
injection
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Granted
Application number
EP88102045A
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English (en)
French (fr)
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EP0287761A3 (en
EP0287761B1 (de
Inventor
Daniel F. Brady
Peter W. Rauen
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Ecolab Inc
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Ecolab Inc
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/14—Arrangements for detecting or measuring specific parameters
    • D06F34/22—Condition of the washing liquid, e.g. turbidity
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2105/00—Systems or parameters controlled or affected by the control systems of washing machines, washer-dryers or laundry dryers
    • D06F2105/38—Conditioning or finishing, e.g. control of perfume injection
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2105/00—Systems or parameters controlled or affected by the control systems of washing machines, washer-dryers or laundry dryers
    • D06F2105/42—Detergent or additive supply

Definitions

  • the present invention relates generally to the neutralization of oxidizing agents in a laundry solution, and more particularly to apparatus and a method for automatically monitoring and precisely controlling the concentration of oxidizing and reducing agents in the final rinse step of a laundry cycle.
  • oxidizing agents such as destainers and bleaches for treating laundry during a wash formula or cycle is commonplace today in both residential and commercial laundering operations.
  • the most commonly used strong bleaching agents are sodium hypochlorite (chlorine bleach) and potassium permanganate.
  • Chlorine bleach is more popular than the other major type of bleach, hydrogen peroxide, because it costs significantly less, is more effective at removal of certain types of stains, and is a better sanitizer.
  • a disadvantage of using destainers such as chlorine bleach is that fabric damage can result if the bleach is overused or if the bleach is not thoroughly rinsed from the fabric.
  • Chlorine bleach is an example of an oxidizing agent that works by releasing "free" oxygen which, in turn, reduces stains. If residual chlorine is allowed to remain in the fabric as a result of the laundering cycle, the oxygen-producing agent of the bleach will continue to attack the fabric's fibers which are converted into oxidized cellulose known as oxycellulose. As a result, the fabric may develop holes or tears in weakened areas. Because the tensile strength of the fabric decreases, the fabric's wear life is shortened and the fabric tears more easily. The damage caused is irreversible. Further, even a relatively small amount of residual chlorine, for example 1 to 2 parts per million, is sufficient to cause fabric damage.
  • chlorine bleach oxidizing agents For the sake of simplification, the remainder of the discussion will address only chlorine bleach oxidizing agents; however, it will be understood that the general problems and principles discussed with regard to chlorine bleach oxidizing agents apply equally well to other types of destainers and oxidizing agents and to their respective neutralizing or reducing agents, when discussed.
  • tunnel washers are becoming increasingly popular in industrial laundry applications, particularly for such applications as the processing of hospital, hotel and other linen supply works, where large quantities of laundry must be cleaned daily.
  • tunnel washers include a series of individual modules or compartments each of which corresponds to a different step in the wash formula or cycle.
  • the textiles to be washed are automatically transported through a continuous loading, washing, rinsing, conditioning and extracting process as they progress from the input to the output of the tunnel washer.
  • the tunnel washing technique significantly reduces labor, since once the laundry is sorted into batches which are successively loaded into the input hopper of the tunnel washer, they are not handled again until they have been conditioned or dried.
  • Utility costs associated with tunnel washers are lower than conventional-type washing systems and processing time is significantly reduced since there is no delay time for water filling of the machine or waiting time for drying or extracting operations.
  • Tunnel washers are basically constructed in either double drum (modular) configuration or single drum (monoshell) configuration.
  • the modular washers have adjacent but separately defined individual compartments each of which performs a different function.
  • the laundry batches progressively move through the compartments which form an inner cylinder of the machine, and are successively transferred from module to module upon completion of the process step therein by raising the laundry batches above the center line of the washer and sliding them through a central connection between the modules.
  • the single drum tunnel washers typically use an Archimedes' screw principle which uses a screw member that extends longitudinally through the drum for defining the various steps of the wash formula and for moving the batches of laundry forward through the drum.
  • each turn or segment of the spiral screw defines a laundry compartment, and the transfer action is achieved when the cylinder or screw rotates through one complete revolution, to move the textiles forward into the next compartment.
  • Tunnel washing apparatus is well known in the art, and a complete description of such apparatus will not be defined herein. The foregoing merely serves as a brief introduction of the advantages to be achieved by the use of tunnel washers in commercial laundering applications, and as a prelude to the problems created by such washing systems in the neutralization of excess oxidizing agents in laundry processed thereby.
  • a tunnel washer apparatus requires approximately three times the amount of bleach for effectively treating a batch of laundry, than does a washer of "conventional" tub design.
  • One reason for the excessive bleach requirement is that the bleach to be effective, is typically added during the wash cycle in a tunnel washer, in which the presence of detergents and alkalines significantly raise the pH levels of the solutions in the washing chambers. Even if the bleach is added during a rinse cycle in a tunnel washing system, a significant amount of bleach is required because of the relatively low temperatures involved at that stage and the relatively high flow rate of water in the rinse zone.
  • the industry has typically resorted to adding neutralizing agents, typically at the final "rinse" stage of the laundry cycle for neutralizing the excess chlorine.
  • the neutralizing agent is typically referred to as an antichlor product.
  • a common antichlor is sodium thiosulfate.
  • the final cycle step is typically used to recondition the laundry to add such conditioning chemicals as softeners, sours and the like, that had been previously stripped from the laundry, back into the textiles.
  • the antichlor or neutralizing agent that is added to the final rinse step for neutralizing excess chlorine in the fabric has been added on a "timed-feed" basis. That is, a fixed, predetermined amount of antichlor has typically been added to each batch of laundry at the final rinse cycle, regardless of the actual amount of residual chlorine in the laundry requiring neutralization.
  • the amount of antichlor added to the rinse has on occasion been varied from cycle to cycle depending upon the type of fabric within the rinse compartment, which may, for example, have a history of retaining more or less chlorine.
  • the "timed-feed" technique for adding antichlor neutralizer into the rinse container is a highly speculative technique based on the best guess of the operator or manufacturer of the washing apparatus as to how much neutralizer should be added.
  • the actual amount of oxidizing agent that requires neutralization in the rinse compartment of a washer is highly variable.
  • the residual chlorine level in the rinse solution depends upon a plethora of variables such as on the amount of chlorine added during the wash cycle, on the type of fabric, on the amount of soil present, on the temperature, on the pH level, on the detergent and alkaline level, on how long the laundry has been subjected to the destainer solution, on the amount of iron in the water, and on the type of destainer/oxidizing agent solution that had been used.
  • the presently practiced method of injecting a fixed amount of neutralizing/antichlor agent on a timed­feed basis into the rinse solution, to neutralize the oxidizing agents therein results in a poor solution to the problem.
  • the present invention addresses these problems associated with present-day techniques for neutralizing excessive oxidation agent retention in laundered textiles, by providing an automated method and apparatus for accurately neutralizing only that amount of oxidizing agent actually present in the laundry solution during any given laundry cycle and which prevents the overinjection of neutralizing or reducing agents into the laundry cycle that can lead to fabric damage.
  • the present invention provides an automated method and apparatus for neutralizing excess oxidizing agents such as destainer chemical additives in a laundering solution such as at the final rinse stage of a wash formula.
  • the oxidation reduction potential of the solution to be neutralized is constantly monitored in a closed loop system.
  • the monitored oxidation reduction potential signal is compared with a signal representing the desired neutralization level of the solution and enables injection of neutralizing agents to the solution in response to the compared signals, until the measured oxidation reduction potential signal indicates oxidation agent neutrality within the solution.
  • the neutralization agent injection is performed on a periodic pulsed basis with an interpulse duty cycle sufficiently long to enable the last-injected measure of neutralizing agents to thoroughly disperse and react in the solution, before injection of additional neutralizer agent is permitted.
  • Injection of neutralizer reduction agents into the solution is accurately controlled such that once neutralization of the oxidizing agents present in the solution is achieved, injection of additional neutralizing reduction agents is prevented, so as to maintain the concentration of both reduction and oxidation agents in the solution preferably to within approximately 1 part per million.
  • the invention effectively regulates the oxidation and reduction agents so as to practically eliminate 100% of their residual remains in the fabric following a treatment cycle.
  • the present invention also reduces the cost of neutralization treatments by eliminating overinjection of expensive reducing agents to the bath and extends the fabric-wear life by reducing retained oxidation agents and salts therein.
  • a method of neutralizing oxidation agents in a laundry bath comprising:
  • the neutralization process more preferably terminates the neutralizer injection procedure when the amount of oxidizing agent to be neutralized which remains in the bath is less than 2 parts per million and even more preferably when it is less than 1 part per million, or most preferably only after the neutralizing agent totally neutralizes the oxidizing agent in the bath.
  • the above injection process further controls injection of the neutralizing agent into the bath so as to prevent undesirable overinjection of the neutralizing agent above a level of 20 parts per million level of unreacted neutralizing agent and more preferably still so, as to prevent overinjection of the neutralizing agent above a 1 part per million level of unreacted neutralizing agent.
  • such injection is performed on an intermittent periodic pulsed basis, by a pump which is selectively and periodically energized in response to the real-time measured amount of oxidizing agent present in the bath at any particular instant of time.
  • a method of automatically neutralizing an oxidizing agent in a laundry bath which comprises the steps of:
  • a method of laundering a textile including the steps of:
  • apparatus for performing the above­described methods of neutralizing oxidizing agents in a laundry bath comprises:
  • such apparatus which also includes means for terminating the injection of neutralizing agents into the bath before excess unreduced neutralizing agent being introduced into the bath exceeds 20 parts per million, and still more preferably before such excess unreduced neutralizing agent in the bath exceeds 5 parts per million and most preferably before they exceed 1 part per million.
  • apparatus for automatically neutralizing oxidizing agents in a laundry bath comprising:
  • While the present invention can be used to neutralize the contents of a container of any type of laundry machine, its preferred use is with commercial laundry machines, and particularly with those typically referred to as batch washer systems and to continuous batch washer systems referred to as "tunnel washers".
  • the preferred embodiment of the invention will be described with respect to its application with a tunnel washer system.
  • a diagrammatic illustration of a typical continuous batch tunnel washer system is schematically illustrated in Fig. 1.
  • Such tunnel washers are well known in the art, and the details of construction thereof will not be set forth herein. Rather, a brief functional description of a tunnel washing system should suffice to illustrate how the present invention can be used to advantage therewith in commercial laundry applications.
  • Typical of such a washer system would be the double-shell tunnel washer as, for example, manufactured by Pellerin Milner Corporation of Kenner, Louisiana, under its Model CBW label.
  • the tunnel washer contains ten separate laundry processing modules or containers, generally indicated at 11-20.
  • Each of the modules is associated with a portion of the complete laundering cycle. While ten such modules and laundry functions are illustrated in Fig. 1, it will be .understood that the number of steps in the laundering cycle and modules employed therefor can widely vary, depending upon the particular laundering requirements of the equipment.
  • the various modules and laundering functions are indicated as: Flush (11), Break (12), Break (13), Suds (14), Flush (15), Bleach (16), Rinse (17), Rinse (18), Rinse (19) and Conditioning (20).
  • each of the modules 11-20 is uniquely associated with performing its associated "function" on a batch of laundry contained in that module.
  • Each of the modules 11-20 is operatively connected with one another, generally in longitudinal alignment such that a batch of laundry can progressively move through the tunnel washer 10 during a complete laundering cycle, from the first module 11 to the final module 20.
  • Each module is sized to contain a "batch" of laundry, generally illustrated at "L" in Fig. 1.
  • the batches of laundry are introduced into the input hopper 10A of the washer 10, and are withdrawn from the exit end 10B of the washer, where the laundry is typically conveyed to extraction and drying apparatus (not illustrated).
  • Means (not illustrated) typically in the form of a large auger which longitudinally extends from the input end 10A to the output end 10B of the washer 10 simultaneously successively moves the batches of laundry from module to adjacent module during the laundering cycle.
  • the length of time that a batch of laundry remains in any particular module varies depending upon the design of the tunnel washer, and is typically from three to ten minutes depending on the chemical additive formulas, and the type and amount of laundry being processed.
  • the various laundry processing steps performed within the modules 11-20 of the tunnel washer are typically under microprocessor or computer control (not illustrated) which provide for the proper addition and extraction of water and additives including such things as detergent, bleach, softeners and the like as the batches of laundry automatically progress through the tunnel washer.
  • the primary control network also controls the reuse of solutions, where appropriate, between adjacent modules and the reuse of recovered water from, for example, extraction or drying processes.
  • the primary control network is also responsible for properly timing the movement of batches of laundry "L" between modules at the completion of steps of the cycle and can typically be programmed to distinguish between incompatible batches of laundry that have been successively loaded into adjacent modules of the washer so that cross-contamination between such incompatible batches of laundry is avoided (as for example, when "white” clothes follow “colored” clothes).
  • the primary control network also is responsible for determining the type and quantity of chemicals that will be added to each module for the particular batch of laundry being processed thereby, for determining whether the modules will be filled rapidly or slowly, and for determining the mode of drainage of the respective modules.
  • Fig. 1 the various means for filling the respective module containers of the washer 10 are schematically illustrated near the upper portions of the respective modules by arrows with the following designations: "CA” meaning Chemical Augmentation; "FF” meaning Fast Fill; and “SF” meaning Slow Fill. Draining of the module containers is schematically illustrated by arrows exiting from the lower portions thereof with the following designations: “FD” meaning Fast Drain; “SD” meaning Slow Drain; and “TD” meaning Transfer Drain.
  • Each of the modules which has a Transfer Drain outlet includes a transfer conduit which flows back into the immediately preceding adjacent module, providing an inlet thereto, designated in Fig. 1 as "TI" meaning Transfer Inlet.
  • Each of the "TI/TD” conduit arrangements has associated therewith a pair of valves (generally designated at “V” in Fig. 1) operatively controlled by the laundry machine primary control network (not illustrated) for directing solution counterflow between adjacent modules, as dictated by the laundering requirements.
  • the tunnel washer 10 of the embodiment illustrated also includes a pump “P” for pumping water from a “Reuse Water Tank” 22 through, a filter 23 to a fill inlet (generally designated at "F") leading into the input hopper 10A of the washer 10. Water recovered from various operations such as extraction and drying stages may provide a source of input water for the tank 22.
  • a batch of laundry "L” is indicated in Fig. 1 as resting on a conveyor 24 adjacent the inlet hopper 10A, awaiting introduction to the tunnel washer 10.
  • the conveyor 24 is also under control of the primary control network of the washer 10.
  • tunnel washer described above is merely illustrative of one configuration of many possible variations of such continuous batch washing systems currently found in the art and of others that fall within the broad description of such systems.
  • the present invention provides an automated method and apparatus for removing excess oxidizing agents such as destainer chemical additives from the laundry solution at the final rinse stage or process of the laundering cycle, to thereby, remove excess oxidizing agents from the laundry being processed at that stage.
  • the present invention not only automatically removes the excess oxidizing agents from the laundry but also safeguards against the addition of excess neutralizer chemicals, which can also have a detrimental effect on the laundry as well as inflating the cost of the neutralizing process. While the principles of this invention could be applied to any of the processing steps in a washing cycle, they are most practically applied at the "Final Rinse" stage in a laundering cycle, just prior to the "reconditioning" of the laundry by the addition of such additives as starch, sours, etc.
  • the neutralizer additives supplied to the Rinse module 19 are provided through an inlet port designated as "NA" (meaning Neutralizer Additive).
  • the neutralizer additive is provided from an appropriate Neutralizer Supply Source 26, and is transmitted to the "NA" input port by means of a pump 27.
  • the pump may be of any configuration well known in the art which is suitable when energized to deliver a known quantity of pumped liquid to its outlet port per given period of pumping time.
  • the pump is a peristaltic type, as for example manufactured by the assignee hereof, Ecolab Inc., under its DRYMASTERTM Model P pump designation.
  • the pump is controlled by an Automatic Neutralizer Control Circuit, hereinafter described in more detail and generally illustrated at 30, which receives input signals by means of a signal flow path 32 from a pair of sensor probes, positioned within the Rinse module 19 and generally illustrated at 34 in Fig. 1.
  • the control signal from the Automatic Neutralizer Control Circuit 30 to the pump 27 is provided by means of a signal flow path generally designated at 36.
  • the Automatic Neutralizer Control Circuit 30 is illustrated in functional block diagram form.
  • the terminology "signal flow path" will be used to refer to that "course" traversed by signals between functional blocks of a circuit.
  • Such signal flow paths can in reality comprise one or a plurality of actual conductors, connectors and the like.
  • the conductors will bear the same reference numeral as the signal flow path, wherein individual conductors thereof will be further designated by subdivisional characters.
  • each of the electrical components is properly connected to appropriate supply and ground and bias sources in order to properly operatively energize the respective circuits.
  • the Automatic Neutralizer Control Circuit 30 is illustrated as it would typically functionally appear when connected to neutralize oxidation agents in solution 15 in a container such as a solution carrying laundry container 19 ⁇ as it might appear during the "Rinse" portion of a laundry cycle.
  • the sensor probe member 34 is operatively disposed within or in relation to the container 19 ⁇ so as to sense the electrical characteristics of the oxidation agents within the solution 15 to be neutralized.
  • the probe 34A is, in the preferred embodiment, a platinum electrode suitable for measuring the "oxidation reduction potential" of the solution 15, and the probe 34B comprises a reference electrode.
  • the oxidation reduction potential electrode 34A determines the level of oxidizing agents present in the solution 15.
  • chlorine is the oxidizing agent.
  • the structure and use of such electrodes is well known in the art, and will not be detailed herein. It will be understood that while a platinum O.R.P. Electrode is disclosed with respect to the preferred embodiment, other appropriate probe materials of inert metals as well as other types of sensors for determining the level of oxidizing agents present in the solution 15 could equally well be employed.
  • the signal output from electrodes 34A and 34B are respectively transmitted by means of signal flow paths 32A and 32B respectively to an Amplifier and Signal Conditioning functional block 37.
  • the reference electrode 34B is connected to and forms the reference potential bus, hereinafter referred to throughout the drawing as 100.
  • the signal output from the Amplifier and Signal Conditioning functional block 37 is applied by means of a signal flow path 38 to one signal input 40a of a Comparator network 40.
  • the output signal from the Amplifier and Signal Conditioning functional block 37 can also be applied to an appropriate Display, generally illustrated at 39.
  • a second input signal is applied to a second input terminal 40b of the comparator 40 from a functional block generally designated as a Set Point Adjustment block 42 by means of a signal flow path 41.
  • the output signal from the Comparator 40 is applied by means of a signal flow path 43 to an Adjustable Pulse Control functional block 44.
  • the signal output from the Adjustable Pulse Control block 44 is carried by means of the signal flow path 36 to energize the Pump 27.
  • the Pump 27 is operative to pump neutralizing agent (in the preferred embodiment "antichlor") from a source of such neutralizing agent 26 which is carried by means of the supply lines 28 and 29 to the Neutralizer Additive (NA) inlet port to the container 19 ⁇ .
  • neutralizing agent in the preferred embodiment "antichlor”
  • the Amplifier and Signal Conditioning functional block 37 is operative to receive the sensed signal provided by the O.R.P. Electrode 34A and to provide a clean representation thereof to the Comparator network 40.
  • the Amplifier and Signal Conditioning functional block 37 is illustrated in more detail in Fig. 3.
  • the Reference Electrode 34B is illustrated as being operatively connected to the reference bus 100.
  • the sensed signal output from the O.R.P. Electrode 34A is carried by means of the signal flow path 32A to the noninverting input terminal of an operational amplifier 37.1.
  • the amplifier 37.1 is appropriately connected to positive and negative supply potentials indicated by (+V) and (-V) respectively.
  • the positive and negative supply potentials (+V) and (-V) respectively represent regulated voltage supply buses appropriately connected to an appropriate supply power source.
  • the supply potentials (+V) and (-V) are (+12 volts) and (-12 volts) respectively.
  • the inverting input terminal of amplifier 37.1 is connected by means of a resistor 37.2 to the wiper arm of a variable resistor 37.3.
  • the respective ends of variable resistor 37.3 are connected between the positive and negative supply voltages (+V) and (-V) respectively.
  • a feedback resistor 37.4 is connected between the signal output of amplifier 37.1 and its inverting input terminal.
  • the output terminal of amplifier 37.1 is directly connected to the noninverting input terminal of a second operational amplifier 37.6.
  • the amplifier 37.6 is properly operatively connected to the positive and negative supplies (+V) and (-V) respectively, and has its noninverting input terminal connected by means of a resistor 37.5 to the reference bus 100.
  • a variable resistor 37.7 is connected in series with a fixed resistor 37.8 in the feedback loop between the signal output terminal and the inverting input terminal of amplifier 37.6.
  • a feedback capacitor 37.9 is also connected in the feedback loop of amplifier 37.6, in parallel with resistors 37.7 and 37.8.
  • the output of amplifier 37.6 provides the signal output for the Amplifier and Signal Conditioning functional block 37, and is directly connected to the signal flow path 38.
  • the amplifiers 37.1 and 37.6 are type TL 084 operational amplifiers.
  • the invention is not to be construed as limited in any manner by the particular type of circuit components herein described. Rather, such circuit components are merely typical of particular circuit components that have been found to function satisfactorily in the circuit configurations illustrated.
  • the amplifiers 37.1 and 37.6 function as unity gain amplifiers to condition and stabilize the sensed signal (which can be in the low millivolt range) received from the O.R.P. Electrode 34A.
  • the variable resistor 37.3 "zeros out" imbalances in the sensor electrodes 34.
  • Amplifier 37.6 provides a damping influence to the sensed signal with capacitor 37.9 acting to eliminate signal discrepancies which may appear in the sensed signal as a result of turbulence, bubbles or the like in the solution 15. It should also be noted that the signal flow paths leading from the sensor electrodes 34 to the Amplifier and Signal Conditioning circuits 37 are shielded to eliminate extraneous noise and interference signals.
  • the signal output from the Amplifier and Signal Conditioning circuit 37 is applied by means of the signal flow path 38 to the Comparator network 40.
  • the signal flow path 38 is connected by means of a resistor 40.1 to the inverting input terminal of an operational amplifier 40.2.
  • the noninverting input terminal of amplifier 40.2 is connected to the reference bus 100.
  • a resistor 40.3 and a capacitor 40.4 are connected in parallel in the feedback loop between the signal output and inverting input terminals of amplifier 40.2.
  • the signal output and inverting input terminals of 40.2 also form input terminals 40b1 and 40b2 for connection to receive signals from the signal flow path 41 (see Fig. 2), which will be described in more detail hereinafter.
  • amplifier 40.2 is a type TL 082 operational amplifier.
  • amplifier 40.5 is a type LM 311 open collector output comparator amplifier.
  • the positive bias terminal of amplifier 40.5 is connected to the reference bus 100, and its negative bias terminal is connected to the negative bias supply (-V).
  • the emitter of the output transistor of amplifier 40.5 is also connected to the negative bias supply (-V).
  • a resistor 40.6 is connected between the signal output and the noninverting input terminals of amplifier 40.5.
  • the noninverting input terminal of amplifier 40.5 is also connected to the inverting input terminal of a second open collector output comparator amplifier 40.7 and provides a third input terminal 40b3 for receiving signals from the signal flow path 41 from the Set Point Adjustment functional block 42.
  • amplifier 40.7 is also a type LM 311 operational amplifier, which has its positive bias terminal connected to the reference bus 100 and its negative bias terminal and the emitter of its output transistor connected to the negative bias supply (-V).
  • the signal output of amplifier 40.5 is connected by means of a resistor 40.8 to the noninverting input terminal of amplifier 40.7.
  • the noninverting input terminal of amplifier 40.7 is also connected by means of a resistor 40.9 to the reference bus 100, and is connected by means of a capacitor 40.10 to the negative bias supply potential (-V).
  • the signal output from amplifier 40.7 is directly applied to the signal flow path 43 for providing an input reset signal to the Adjustable Pulse Control network 44, as hereinafter described in more detail.
  • the Set Point Adjustment functional block 42 (see Figs. 2 and 4) comprises a plurality of resistors and capacitors that can be adjusted (as hereinafter described) to vary the various signals applied to amplifiers 40.2, 40.5 and 40.7 of the Comparator network 40.
  • a plurality of resistors 42.1-­42.8 are switchably connected in parallel by means of the conductors 41A and 41B with resistor 40.3 and capacitor 40.4 in the feedback loop of amplifier 40.2, to selectively vary the gain of amplifier 40.2.
  • Each of the resistors 42.1-42.8 is respectively connected in series with a switch 42.11-42.18 which can be selectively opened or closed to connect the desired resistor(s) in parallel in the feedback loop of amplifier 40.2.
  • the switches 42.11-42.18 are, in the preferred embodiment, comprise thumb-wheel switches operatively connected to provide a binary coded two digit decimal number, wherein resistors 42.1-42.4 and their accompanying switches 42.11-42.14 are associated with the "one's digit" of the number, and wherein resistors 42.5-42.8 and their associated switches 42.15-42.18 are associated with the "ten's digit" of the number.
  • the binary coded decimal output designations of the various resistor/switch pairs are indicated to the right of the respective switches in Fig. 5.
  • the second portion of the Set Point Adjustment network 42 comprises a resistor/capacitor network that provides in the preferred embodiment, a fixed bias potential to the noninverting input terminal of amplifier 40.5 by means of the conductor 41C through the input terminal 40b3.
  • a capacitor 42.20 is connected in parallel with a resistor 42.21 between the negative bias supply potential (-V) and the conductor 41C.
  • a pair of resistors 42.22 and 42.23 are also connected in parallel between the reference bus 100 and the conductor 41C.
  • the pair of parallel circuits just described provides a constant 5 volt reference signal to the noninverting input terminal of amplifier 40.5.
  • the signal output of Comparator 40 is carried by means of the signal flow path 43 to a "reset" input terminal of a Timer circuit 44.1 of the Adjustable Pulse Control network 44.
  • the Timer 44.1 is a type 555 timer having its V cc input terminal connected to the reference bus 100 and its reference or (GND) terminal connected to the negative bias supply potential (-V).
  • the timer also has a "threshold” terminal designated as (THD), a “trigger” terminal designated as (TRIG) and a “discharge” terminal designated as (DISCHG).
  • the threshold (THD) and trigger (TRIG) input terminals are commonly connected and are connected by means of a capacitor 44.2. to the negative bias potential (-V).
  • the (THD) and (TRIG) terminals are also connected by means of a variable resistor 44.3 and a fixed resistor 44.4 to the reference bus 100.
  • the movable wiper of variable resistor 44.3 is connected to the discharge (DISCHG) terminal of Timer 44.1, and is also connected by means of a diode 44.5 to the (THD) and (TRIG) terminals.
  • Timer 44.1 The signal output of Timer 44.1 is connected by means of a resistor 44.6 to the base of an npn transistor 44.7.
  • the emitter of transistor 44.7 is directly connected to the negative bias potential (-V) and its collector is connected to the cathode of a light emitting diode 44.8.
  • the anode of diode 44.8 is connected to the stationary contact of a switch 44.9.
  • the movable wiper of switch 44.9 moves between a pair of contacts designated at (x1) and (x2) in Fig. 4.
  • Contact (xl) of switch 44.9 is connected by means of a resistor 44.10 to an unregulated power supply source, generally designated at "PS" in Fig. 4, and it is also directly connected to a first input terminal of a triac driver network 44.11.
  • driver network 44.11 is a type MOC 3030 optically coupled triac driver network.
  • the switch When the movable wiper of switch 44.9 is positioned in engagement with contact (x1), the switch disables the optical coupler driver 44.11.
  • the optical coupler When positioned with movable wiper in engagement with contact (x2), the optical coupler is enabled for operation, upon further conduction of transistor 44.7, as hereinafter described.
  • Driver 44.11 has a first output terminal connected by means of a resistor 44.12 to a first power terminal of a triac 44.13, and closes an enabling supply path for Pump 27 by means of a conductor 36A of signal flow path 36.
  • the second output terminal of the triac Driver 44.11 is connected to the gate terminal of triac 44.13 and is also connected by means of a resistor 44.14 to the second power terminal of triac 44.13, and to a second conductor 36B of the signal flow path 36 leading to the Pump 27.
  • a capacitor 44.15 is connected in series with a resistor 44.16 across the power terminals of triac 44.13 and between the conductors 36A and 36B providing filtering of the triac generated signals.
  • the circuitry described above enables accurate, automatic neutralization of oxidizing agents in a laundry bath, with practically zero residual neutralizing agent carryover remaining in the bath after the neutralization process.
  • the Amplifier and Signal Conditioning Network 37 provides a clean sensed signal from the input probes 34 which accurately reflects the measured oxidation reduction potential levels of the solution 15 and which accounts for perturbations within the solution caused by turbulence, bubbles or the like.
  • ppm parts per million
  • the measured oxidation reduction potential as it correlates to parts per million of the oxidizing agents in the bath varies as a function of the pH level of the bath. For example, in contrast to the above example wherein a pH level of 10 was assumed for the bath 15, if the pH level of the bath 15 were to change to a different level such as to a pH of 9, there would be a corresponding change in the measured oxidation reduction potential level at the probes 34 as well as in the correlation factor of such measured oxidation reduction potential to the actual level of oxidizing agents appearing in the bath.
  • a 1.0 millivolt change in the measured oxidation reduction potential level at the probes 34 might now represent a change in the level of oxidizing agents in the bath by 1 ppm (in contrast to the 0.1 millivolt per 1 ppm example that existed for a pH level of 10).
  • a typical pH value for a laundry solution in a tunnel washer final rinse stage is between 9 and 11.
  • a typical level of excess chlorine appearing in such bath before neutralization may be on the order of 10 to 50 parts per million.
  • the measured oxidation reduction potential values as correlated to the amount of oxidizing agents (in ppm) in a bath for any given pH value can be empirically determined.
  • the values of the components in the Comparator 40 network and in the Set Point Adjustment 42 network have been selected for use with a tunnel washer apparatus wherein the pH of the solution in the final Rinse module in which the solution is being neutralized, is relatively constant from batch to batch, at a pH level of approximately 9. Therefore, once the Set Point Adjustment selections (as hereinafter described) are made for a desired percentage of neutralization in a given system, such settings do not require change from day to day or from batch to batch as the laundry machine performs successive laundering cycles.
  • the gain of amplifier 40.2 can be selected by means of the thumb­wheel switches 42.11-42.18 and their associated resistors 42.1-42.8 to provide the desired output operating level from amplifier 40.2 that will be compared against the reference signal applied to comparator amplifiers 40.5 and 40.7.
  • the gain of amplififier 40.2 will be set such that its output voltage at the "neutral" oxidation reduction potential measurement of the bath, identically equals the reference voltage level applied to conductor 41C.
  • the output signal from amplifier 40.2 should equal the value of the reference signal applied by means of the conductor 41C to the comparator amplifiers 40.5 and 40.7, at such zero ppm level.
  • a constant reference voltage level applying on conductor 41C
  • 5 volts has been selected as an optimum operating level for the comparator amplifiers 40.5 and 40.7.
  • the signal output of amplifier 40.2 should also be 5 volts, by proper selection of the nominal gain of the amplifier 40.2 with the resistor/switching network. Any deviation from the measured "neutral" oxidation reduction potential value of 400 mv measured at the probes 34 represents an undesirable excess of chlorine in the solution, or conversely an excess of antichlor in the solution.
  • the amplification level of the measured deviations from the neutral 400 mv level are multiplied by the gain selection entered into the Set Point Adjustment 42 network by means of the resistors 42.1-42.8 and their associated switches 42.11-42.18.
  • the resistor 42.1-42.8 values have been selected such that their binary coded decimal representations set by switches 42.11-42.18 indicate a multiple of the "neutral" millivolt value of the oxidation reduction potential measurement of the solution.
  • a switch selection reading of "01” would correspond to a "neutral” reading of 10 mv, a reading of "13” to a “neutral” reading of 130 mv, etc.; wherein the output voltage from amplifier 40.2 at the respective "neutral” gain settings would be 5 volts, to match the selected reference voltage level of the preferred embodiment circuit configuraiton.
  • a typical chlorine content within the solution 15 which is to be neutralized at the final Rinse station can typically vary from 10 to 50 parts per million. It is desirable to reduce such residual chlorine content to as near zero ppm as possible, without introducing excessive or residual antichlor to the solution which can be as undesirable as the chlorine itself.
  • the Automatic Neutralizer Control Circuit 30 operates in closed loop manner to add antichlor to the rinse solution 15 in measured increments by operating the Pump 27 on a pulsed basis, in response to the actual measured oxidation reduction potential value by the probes 34. The determination as to whether antichlor injection to the solution 15 is necessary, is made by the Comparator network 40.
  • the comparator amplifier 40.5 continuously monitors the measured oxidation reduction potential signal provided by amplifier 40.2 against the fixed reference level on conductor 41C established by the reference potential circuit of the Set Point Adjustment network 42. If the measured oxidation reduction potential signal exceeds the fixed reference signal at the input to amplifier 40.5, an output signal is provided by comparator amplifier 40.5 to the noninverting input of comparator amplifier 40.7.
  • comparator amplifier 40.7 acts as a "delay" comparator which ensures that the signal received from amplifier 40.2 must exceed the fixed reference level on conductor 41C for at least a continuous predetermined period of time before the comparator network 40 will provide a reset signal to Timer 44.1.
  • the "delay" function has been set for a turn-on delay of 2 seconds and a turn-off delay of 0.1 seconds. The turn-on delay is established by the charging time constant of capacitor 40.10. The turn-off delay is provided by discharge of capacitor 40.10 through resistor 40.8 and the open collector output terminal of amplifier 40.5 to the negative bias supply bus (-V).
  • the comparator network 40 provides a logical "high” reset signal to the "reset" input terminal of Timer network 44.1.
  • Timer 44.1 is operative to establish a pulsed duty cycle for activating the Pump 27 so as to inject a predetermined amount of antichlor into the solution bath 15 on each energized cycle of the Pump.
  • the Timer 44.1 takes approximately 20 seconds to charge following receipt of a reset signal from the comparator 40, and approximately 1 second to discharge before it can be reset again by the comparator 40.
  • the capacitor 44.2 of Timer 44.1 is charged by the circuit path established from the reference 100, through resistor 44.4, the left portion of resistor 44.3 (as viewed in Fig. 4), and the diode 44.5.
  • Pump 27 operates to inject a measured amount of antichlor additive to the solution bath 15.
  • an injection of antichlor to the solution bath 15 during one pulsed interval of pump operation operates to reduce the measured oxidation reduction potential by approximately 2-3 millivolts.
  • a change in 1.0 mv has been found to correlate to approximately a 1 ppm change in the presence of unreduced oxidizing agents in the bath.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Detail Structures Of Washing Machines And Dryers (AREA)
  • Detergent Compositions (AREA)
  • Accessory Of Washing/Drying Machine, Commercial Washing/Drying Machine, Other Washing/Drying Machine (AREA)
EP88102045A 1987-04-24 1988-02-12 Vorrichtung und Verfahren zum Neutralisieren von oxidierenden Mitteln in einer Waschmaschine Expired - Lifetime EP0287761B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4216387A 1987-04-24 1987-04-24
US42163 1987-04-24

Publications (3)

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EP0287761A2 true EP0287761A2 (de) 1988-10-26
EP0287761A3 EP0287761A3 (en) 1988-11-30
EP0287761B1 EP0287761B1 (de) 1992-09-09

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EP88102045A Expired - Lifetime EP0287761B1 (de) 1987-04-24 1988-02-12 Vorrichtung und Verfahren zum Neutralisieren von oxidierenden Mitteln in einer Waschmaschine

Country Status (5)

Country Link
EP (1) EP0287761B1 (de)
JP (1) JPS63283700A (de)
AU (1) AU597474B2 (de)
DE (1) DE3874391T2 (de)
NZ (1) NZ223338A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120233785A1 (en) * 2011-03-14 2012-09-20 Herbert Kannegiesser Gmbh Method and apparatus for washing in particular items of laundry
EP2789723A1 (de) * 2013-04-11 2014-10-15 Herbert Kannegiesser GmbH Verfahren zum Nassbehandeln, vorzugsweise Waschen, von Wäsche
US10995305B2 (en) 2012-08-20 2021-05-04 Ecolab Usa Inc. Method of washing textile articles

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6945324B2 (ja) * 2016-04-01 2021-10-06 ライオンハイジーン株式会社 洗濯方法及び中和組成物

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2920492A1 (de) * 1978-06-12 1979-12-20 Schwarzenberg Waschgeraete Verfahren und einrichtung zur steuerung des waschprozesses in haushaltwaschgeraeten
FR2455648A1 (fr) * 1979-05-03 1980-11-28 Licentia Gmbh Procede pour la surveillance et la commande du programme, notamment l'admission de l'eau et/ou l'addition de l'agent nettoyant ou de l'agent de rincage dans des machines automatiques a laver le linge ou la vaisselle

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2920492A1 (de) * 1978-06-12 1979-12-20 Schwarzenberg Waschgeraete Verfahren und einrichtung zur steuerung des waschprozesses in haushaltwaschgeraeten
FR2455648A1 (fr) * 1979-05-03 1980-11-28 Licentia Gmbh Procede pour la surveillance et la commande du programme, notamment l'admission de l'eau et/ou l'addition de l'agent nettoyant ou de l'agent de rincage dans des machines automatiques a laver le linge ou la vaisselle

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120233785A1 (en) * 2011-03-14 2012-09-20 Herbert Kannegiesser Gmbh Method and apparatus for washing in particular items of laundry
US10995305B2 (en) 2012-08-20 2021-05-04 Ecolab Usa Inc. Method of washing textile articles
US11773350B2 (en) 2012-08-20 2023-10-03 Ecolab Usa Inc. Method of washing textile articles
EP2789723A1 (de) * 2013-04-11 2014-10-15 Herbert Kannegiesser GmbH Verfahren zum Nassbehandeln, vorzugsweise Waschen, von Wäsche
US20140304925A1 (en) * 2013-04-11 2014-10-16 Herbert Kannegiesser Gmbh Method for the wet-treatment, preferably the washing, of laundry
US10619283B2 (en) 2013-04-11 2020-04-14 Herbert Kannegiesser Gmbh Method for the wet-treatment, preferably the washing, of laundry

Also Published As

Publication number Publication date
EP0287761A3 (en) 1988-11-30
AU597474B2 (en) 1990-05-31
JPS63283700A (ja) 1988-11-21
DE3874391D1 (de) 1992-10-15
AU1136688A (en) 1988-10-27
NZ223338A (en) 1991-01-29
DE3874391T2 (de) 1993-04-22
EP0287761B1 (de) 1992-09-09

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