Patent Application
20250154709
The present invention relates generally to processes and apparatuses for laundering textiles, and more particularly to controlling microbial growth in such processes and apparatuses.
Microbial control within numerous industries is paramount as a means of controlling product quality and operational efficiency. As one such example, within the food processing market, microbial control prevents spoilage of food stuffs. Within the dairy industry, control of both free viable microorganisms and microbial biofilms within process piping is instrumental in maintaining a quality milk supply. In this example, Clean In Place (CIP) chemical/mechanical programs serve to remove microbial “slimes” which may occur on the piping side-walls. Such control of microbial slimes is further necessary in Water For Injection (WFI) systems which produce sterile water for medicinal purposes. Further still, it is known that microbial control within Evaporative Cooling Towers and other Recirculation Water systems is paramount in preventing biofouling, a physical build-up of microbial populations on mechanical process equipment, which impedes operational efficiency and can lead to corrosion of the equipment. Other examples where microbial control in process waters include but are not limited to swimming pools, municipal water fountains and the pulp and paper industry.
Within the professional laundry space, both rental textile and contract processing, a significant volume/proportion of the textile inventory is processed within Tunnel Washers (e.g., Continuous Batch Washers, Batch Washers). These high-capacity laundry machines are responsible for producing tens of thousands of pounds of clean laundry per day, with much of the processed textiles being serviced to the healthcare market, and other marketplaces where microbial integrity of the finished textile is important. Example of the criticality of the microbial integrity of the laundered and customer-ready textiles are the TRSA Hygienically Clean programs which target the Healthcare, Food Service, Food Processing and Hospitality market spaces, along with the NSF Protocol P467 on Hygienically Clean Healthcare Textiles.
The efficacy of the modern tunnel washer is contingent upon the judicial use of water, chemistry, and utilities such as electricity and natural gas to thoroughly clean physical soils, remove and/or destroy microbial loads, and render the organoleptically “clean” fabrics as being “Hygienically Clean.” Whereas a conventional washer/extractor machine may require 2.0, 2.5, or 3.0 gallons of fresh potable water to process one pound of soiled textiles, tunnel washers can effectively process the same pound of soiled textiles with reduced water consumptions of 1.0, 0.75, or 0.5 gallons of fresh potable water by recirculating and reusing the drain waters for subsequent washing. Further, unlike a conventional washer extractor, tunnel washers typically retain a stored water overnight. or even over a multiple day duration as a means of controlling water usages.
While effective for their intended purposes, it has become known that microbial blooms and microbial biofilms can develop and thrive within the process waters of a tunnel washer and within the water tankage and piping of the process equipment. Indeed, microbial counts for sour bath waters from numerous tunnel washers have shown total aerobic plate counts to be over 1000 cfu/ml in some instances. In other words, even though the processes may inject chemical or otherwise treat water that sanitizes textiles, the amount, location, and use of the treatments are not effective to reduce the microbial load of the process waters.
It would therefore be advantageous to both control and monitor the microbial load of the finished laundered textiles as being “Hygienically Clean” while concurrently monitoring and treating the recirculation process waters to minimize microbial proliferation.
As discussed in more detail below, processes and apparatuses have been invented which utilize antimicrobial chemistries to effectively control microbial proliferation of the microbial ecology within tunnel washers. In the present inventions, various chemistries, at application rates and dosages, may effectively destroy a microbial load of a commercial tunnel washers. Thus, microbial biofilms can be permeated, and the viable microbial population reduced through application of antimicrobial chemistries. Further still, various chemistry selections and applications have been made such that colorfastness of the subsequently laundered textiles is not compromised and the end user/wearer of the textiles laundered in the process waters will not experience dermal irritations any more so that when wearing textiles which are routinely professionally laundered. Accordingly, in this application, microbially inhibitive chemistry may be utilized to control the proliferation and biofilm formation within tunnel washer process waters, tankage, and piping.
Accordingly, in one aspect the present invention may be characterized as providing a process for sanitizing a tunnel washing system by: treating water from the tunnel washing system in order to reduce a microbial load of the water.
The treating may include injecting a chemical into the water. The chemical may be selected from a group consisting of: sodium hypochlorite, sodium chlorite, chlorine dioxide, hydrogen peroxide, peracids, phthalimido-peroxy-hexanoic acid, magnesium monoperoxyphthalate (mmpp), sodium percarbonate/sodium perborate, quaternary ammonium chlorides, poly(oxyethylene(dimethyliminio)ethylene (dimethyliminio) ethylene dichloride, tributyl tetradecyl phosphonium chloride, silver nitrate, copper salts, 2,2-dibromo-3-nitriloproprionamide, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 2-bromo-2-nitro-1,3-propanediol, other known antimicrobial compounds, and mixtures thereof.
The treating may occur between wash cycles of the tunnel washer system.
Additionally, it is contemplated that the treating occurs continuously or at intervals.
The process may also include determining a microbial load of the water and determining a treatment based on the determined microbial load. Determining the microbial load of the water may include obtaining a measurement of a parameter of the water, the measurement being utilized to determine the microbial load. When the determined microbial load exceeds a predetermined value, the process may include injecting a chemical into the water to reduce the microbial load of the water. The process may also include determining an amount of the chemical to inject based on the determined microbial load. The measurement may be obtained at regular intervals. The measurement may be obtained online.
In another aspect, the present invention may be characterized as providing a process for controlling microbial proliferation in a tunnel washing system by: washing textiles in a tunnel washing system with at least water; determining a microbial load of the water from the tunnel washing system; and, injecting a chemical into the water of the tunnel washing system in order to reduce a microbial load of the water when the determined microbial load exceeds a predetermined value.
Determining the microbial load of the water further may include obtaining a measurement of a parameter of the water. The measurement is utilized to determine the microbial load. The measurement may be obtained at regular intervals. Additionally, the measurement may be obtained online.
The step of injecting may occur between wash cycles of the tunnel washer.
The process may also include determining an amount of the chemical to inject based on the determined microbial load. The chemical may be selected from a group consisting of: sodium hypochlorite, sodium chlorite, chlorine dioxide, hydrogen peroxide, peracids, phthalimido-peroxy-hexanoic acid, magnesium monoperoxyphthalate (mmpp), sodium percarbonate/sodium perborate, quaternary ammonium chlorides, poly(oxyethylene(dimethyliminio)ethylene (dimethyliminio) ethylene dichloride, tributyl tetradecyl phosphonium chloride, silver nitrate, copper salts, 2,2-dibromo-3-nitriloproprionamide, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 2-bromo-2-nitro-1,3-propanediol, other known antimicrobials and mixtures thereof.
In still another aspect the present invention may be characterized as providing a tunnel washing system having: a tunnel washer configured to received soiled textiles and water and provide laundered textiles; a tank configured to store the water to be recycled to the tunnel washer; a source of a chemical, the chemical configured to reduce the microbial load of the water when the chemical is introduced to the water; and, a line configured to provide the chemical from the source of the chemical to the tunnel washer.
The system may also include a sensor configured to obtain at least one measurement relating to a parameter of the water, a controller configured to receive the at least one measurement and determine a microbial load of the water, and a pump provided in the line. The pump may be in communication with the controller and configured to respond to signals from the controller to adjust an introduction of the chemical to the tunnel washer.
These and other aspects and embodiments of the present invention will be appreciated by those of ordinary skill in the art based upon the following description of the drawings and detailed description of the preferred embodiments.
The attached drawings will make it possible to understand how the invention can be produced and practiced, in which:
As mentioned above, the present invention provides processes and apparatuses for controlling microbial growth within continuous batch washers, or tunnel washers. These inventions aide in producing “Hygienically Clean” textiles via the laundering process, while concurrently attaining the resource conservation objectives of the tunnel washer. Contrary to conventional tunnel washers and processes which recycle waters, the present inventions maintain an aseptic quality of the process waters, minimizing microbial blooms within the process water, and maintaining a process water quality which is microbiologically sanitary such as to generate a “Hygienically Clean” textiles for delivery to an end-user.
Laundry Tunnel Washers are highly efficient production machines which have the ability to process thousands of pounds of soiled laundry while utilizing significantly less consumable resources (water, electricity, natural gas) as compared to single wash-load machines exemplified by washer/extractors. The laundry process waters within a tunnel washer are known to support microbial growth. Such microbial growth is influenced by conditions and factors including:
It can be generally accepted as being true that microbial growth within a tunnel washer is acknowledged by the fact that some/many/most tunnel manufacturers will program a Tunnel Sanitation formula within the operation formula configurations. Further, some tunnel manufacturers and chemical providers to the industry have developed chemical sanitation processes which are to be executed at a time deemed appropriate. The primary drawback to these operations is that they are single point-in-time events which can be compromised soon-after by the environmental and operational conditions conducive to microbial growth noted previously.
Similar to domestic laundry, an objective of the wash process is to remove soils and stains from the used/worn/serviced textile items such that the processed garments/linens are suitable for rewear/reuse. Such organoleptically clean standards are appropriate for select classifications of reusable textiles, including most domestic laundry and some textiles which are processed on a commercial basis. Other classifications of textiles require a microbiological aspect of the cleanliness criteria, wherein the laundered and finished textiles are to meet established criteria for recoverable viable bioburden. Such classifications include reusable healthcare textiles exemplified by patient gowns, healthcare scrubs, patient bedding and toweling, and textiles used in the administration of medical services such as surgical gowns and drapes. Further, other industries including Food Processing, Pharmaceutical, Cosmetic, Restaurants and Food Service have accepted the principles of microbial monitoring of textiles as a means of monitoring their process quality. Thus, microbiology of the professionally processed laundry differs from organoleptic cleanliness evaluations with microbial integrity of the laundered items being paramount.
The terminal operational steps of the tunnel washing process are the souring and finishing of the textiles in the last/end module; and the press or centrifugal extraction of waters out of the laundered textiles. These actions serve to:
Thus, these final waters, both sour water and extraction water can have profiles which are conducive to microbial growth. Indeed, it is believed by some that the textiles cannot be significantly cleaner than the last waters that they were processed/submerged in. For this reason, one part of a “Hygienically Clean” laundering program is to monitor the microbial quality of the waters.
Moreover, it is known in various tunnel washers to use chemistries to sanitize the textiles. However, despite the use of chemistries that are antimicrobial, it is has been shown, based on the continued proliferation of microbial growth, that these amounts which are added to sanitize the textiles are insufficient to reduce or control the microbial load of the water. This attribute may be due in part to the substantivity of select antimicrobial treatments to the laundered textiles. Indeed, if the injected chemicals were sufficient, such a problem would not exist in the industry. Nevertheless, the problem of microbial growth and biofilm formation does exist, and the present invention seeks to address it.
Accordingly, with reference the attached drawings, one or more embodiments of the present invention will now be described with the understanding that the described embodiments are merely preferred and are not intended to be limiting.
With reference to
Although not depicted as such, the tunnel washer 12 includes a plurality of modules, or zones, and a means for moving the textiles through the modules, such as a helix.
Fresh water 16, as well as recirculated or recycled water 18, are provided to the tunnel washer 12. Additionally, various chemicals 20 are provided to the various modules of the wash tunnel. For example, detergents, sanitizers, sours, and others may be injected at desired stages in desired amounts to obtain laundered textiles.
As is known, a press (not shown) may be positioned at the end of the tunnel washer 12. Laundry exits the last module, typically a rinse zone, and enters the press which is generally used to remove excess rinse water from the laundry prior to transporting the laundry to a dryer. The press removes excess water by compressing or squeezing the laundry to expel excess water using hydraulic mechanisms or the like. This press water may be passed to a tank 25 and withdrawn later as the recycled water 18.
It should be appreciated and understood by those of ordinary skill in the art that the tunnel washing system 10 is a schematic drawing and that various other components such as valves, pumps, filters, coolers, tanks, etc. were not shown in the drawings as it is believed that the specifics of some are well within the knowledge of those of ordinary skill in the art and a description of same is not necessary for practicing or understating the embodiments of the present invention. A more detailed description of the tunnel washer 12 is described in, for example, U.S. Pat. No. 11,198,968.
As discussed above, while some of the chemicals 20 injected into the tunnel washer 12 are antimicrobial, the position, amount, and type of chemistries have not sufficiently reduced the microbial load of the water. Moreover, conventional processes and devices only inject such chemicals while the tunnel washer 12 is operating. During downtimes, for example, over night or on the weekends, the microbes in the water may multiply.
Thus, the present invention seeks to address this problem by treating water from the tunnel washing system in order to reduce a microbial load of the water. As shown in
The chemical 22 may be a quaternary ammonium compound, isothiazolin-3-ones, or a peracid. For example, the chemical 22 may be selected from a group consisting of: sodium hypochlorite, sodium chlorite, chlorine dioxide, hydrogen peroxide, peracids, phthalimido-peroxy-hexanoic acid, magnesium monoperoxyphthalate (mmpp), sodium percarbonate/sodium perborate, quaternary ammonium chlorides, poly(oxyethylene(dimethyliminio)ethylene (dimethyliminio) ethylene dichloride, tributyl tetradecyl phosphonium chloride, silver nitrate, copper salts, 2,2-dibromo-3-nitriloproprionamide, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 2-bromo-2-nitro-1,3-propanediol, other known antimicrobial compounds, and mixtures thereof.
The chemical 22 may be injected during a wash cycle, or between wash cycles. Additionally, the chemical 22 may be injected continuously or intermittently.
In order to ensure the appropriate amount of treating occurs, a microbial load of the water may be determined. Microbial monitoring is known as detailed under RAL-GZ 992 Quality Certification, Professional Textile Services.
For example, a sensor 24 may be in the line of the recycled water 18 and/or in the tank 25 for the water, and be configured to take a measurement of a parameter of the water that may be utilized to determine a microbial load. The use of the sensor(s) 24 allows for an online measurement—in contrast with an offline measurement which may include removing water and running a test in a lab. The measurement may be continuous, or it be performed at various intervals.
The sensor(s) 24 are in communication with a controller 26 which may be configured to determine the microbial load from the measurement. For example, the controller 26 may store a look up table that contains previous data points and past conditions which may be used to correlate current data points and determine a present condition.
Once the microbial load has been determined, the controller 26 may determine a treatment based on the determined microbial load. For example, an amount of a chemical to inject may be determined. Again, a lookup table may be used to determine the amount of the chemical 22 to inject based on the determined microbial load.
The controller 26 may be in communication with a pump 28 which is configured to receive signals or commands from the controller 26 to inject the chemical 22. For example, the pump 28 be respond to a command to turn on, to turn off, to increase injection rate, or to decrease injection rate. Any of these would adjust the introduction of the chemical 22 to the water and thus, the tunnel washer 12.
The systems and devices described herein may include a controller or a computing device comprising a processing and a memory which has stored therein computer-executable instructions for implementing the processes described herein. The processing unit may comprise any suitable devices configured to cause a series of steps to be performed so as to implement the method such that instructions, when executed by the computing device or other programmable apparatus, may cause the functions/acts/steps specified in the methods described herein to be executed. The processing unit may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.
The memory may be any suitable known or other machine-readable storage medium. The memory may comprise non-transitory computer readable storage medium such as, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory may include a suitable combination of any type of computer memory that is located either internally or externally to the device such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. The memory may comprise any storage means (e.g., devices) suitable for retrievably storing the computer-executable instructions executable by processing unit.
The methods and systems described herein may be implemented in a high-level procedural or object-oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of the controller or computing device. Alternatively, the methods and systems described herein may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems described herein may be stored on the storage media or the device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein.
Computer-executable instructions may be in many forms, including modules, executed by one or more computers or other devices. Generally, modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically, the functionality of the modules may be combined or distributed as desired in various embodiments.
It will be appreciated that the systems and devices and components thereof may utilize communication through any of various network protocols such as TCP/IP, Ethernet, FTP, HTTP and the like, and/or through various wireless communication technologies such as GSM, CDMA, Wi-Fi, and WiMAX, is and the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.
Laundry press waters were collected and tested for viable microbial load. Examples of such laundry press water microbial loads are presented in the reference Laboratory Book pages (attachment). With 1 fluid ounce approximating 30 milliliters, and 1 pound of a blended polyester/cotton textile having an approximate 1.5 pounds of saturation water, one or ordinary skill in the art would appreciate that 102 to 104 colony forming units (cfu's) per milliliter could lead to a clean dry textile with a viable recoverable microbial limit in excess of 20 cfu per square decimeter (near 16 square inches), the existing certification pass/fail acceptance criteria for Hygienically Clean status.
Using a Milnor standalone washer/extractor, 35 patient gowns were laundered to generate water equivalent to approximately 125 gallons of dirty water from a conventional tunnel washer.
The following day, the dirty water was circulated for approximately 2 hours. A 20 mL sample of the dirty water was taken. Then, the patient gowns, along with a pillowcase, terry bath towel, and scrubs were subject to a low temperature washing cycle with no chemicals used. For the sour step, the dirty water was utilized. A sample of the dirty water was collected. The textiles were dried on high heat, and the pillowcase, terry bath towel, and scrubs were put into bags for RODAC testing. The two dirty water samples were diluted and tested on TSA plates. The results of the tests are shown in TABLES 1 and 2 below.
Using a Milnor standalone washer/extractor, 35 patient gowns were laundered to generate water equivalent to approximately 125 gallons of dirty water from a conventional tunnel washer. The dirty water was then circulated for 1 hour. Subsequently, 4, 30 mL tubes containing bioload cultures previously incubated for 48 hours were added to the dirty water and circulated for another 45 minutes.
The following day, the dirty water was circulated for approximately 2.5 hours. A 20 mL sample of the dirty water was taken. Then, the patient gowns, along with a pillowcase, terry bath towel, and scrubs were subject to a low temperature washing cycle with no chemicals used. For the sour step, the dirty water with microbial load was utilized. A sample of the dirty water was collected. The textiles were dried on high heat, and the pillowcase, terry bath towel, and scrubs were put into bags for RODAC testing. The two dirty water samples were diluted and tested on TSA plates. The results of the tests are shown in TABLES 3 and 4 below.
Using a Milnor standalone washer/extractor, 35 patient gowns were laundered to generate water equivalent to approximately 125 gallons of dirty water from a conventional tunnel washer.
The following day, the dirty water was circulated for approximately 2.5 hours. Subsequently, 4, 30 mL tubes containing bioload cultures previously incubated for 48 hours were added to the dirty water and circulated for another hour.
The following day, the dirty water was circulated again for approximately 2.5 hours. A 20 mL sample of the dirty water was taken.
A treatment of 60 milliliters (approximately 2 oz.) of a biocide containing 20% active 2,2-dibromo-3-nitrilopropionaminde (DBNPA) was injected into the tank containing the dirty water and the water was recirculated. The patient gowns, along with a pillowcase, terry bath towel, and scrubs were subject to a low temperature washing cycle with no chemicals used. For the sour step, approximately 8-9 inches of dirty and chemically treated water was utilized. A sample of the dirty water was collected. The textiles were dried on medium heat, and the pillowcase, terry bath towel, and scrubs were put into bags for RODAC testing. The two dirty water samples were diluted and tested on TSA plates. The results of the tests are shown in TABLES 5 and 6 below.
Using a Milnor standalone washer/extractor, 35 patient gowns were laundered to generate water equivalent to approximately 125 gallons of dirty water from a conventional tunnel washer.
The following day, the dirty water was circulated for approximately 2 hours. Subsequently, 4, 30 mL tubes containing bioload cultures previously incubated for 48 hours were added to the dirty water and circulated for another hour.
The next day, the dirty water was circulated again for approximately 2.5 hours. A 20 mL sample of the dirty water was taken.
A treatment of 60 milliliters of a biocide containing 20% active 2,2-dibromo-3-nitrilopropionaminde (DBNPA) was injected into the tank containing the dirty water and circulated for approximately 3 hours. The patient gowns, along with a pillowcase, terry bath towel, and scrubs were subject to a low temperature washing cycle with no chemicals used. For the sour step, approximately 8-9 inches of dirty and anti-microbially treated water was utilized. A sample of the dirty water was collected. The textiles were dried on medium heat, and the pillowcase, terry bath towel, and scrubs were put into bags for RODAC testing. The two dirty water samples were diluted and tested on TSA plates. The results of the tests are shown in TABLES 7 and 8 below.
Using a Milnor standalone washer/extractor, 35 patient gowns were laundered to generate water equivalent to approximately 125 gallons of dirty water from a conventional tunnel washer.
The following day, the dirty water was circulated for approximately 3 hours. Subsequently, 4, 30 mL tubes containing bioload cultures previously incubated for 24 hours were added to the dirty water and circulated for another 2 hours.
The next day, the dirty water was circulated again for approximately 2.5 hours. A 20 mL sample of the dirty water was taken. The patient gowns, along with a pillowcase, terry bath towel, and scrubs were subject to a low temperature washing cycle with no chemicals used. For the sour step, approximately 8-9 inches of dirty water was utilized. A sample of the dirty water was collected. The textiles were dried on medium heat, and the pillowcase, terry bath towel, and scrubs were put into bags for RODAC testing. The two dirty water samples were diluted and tested on TSA plates. The results of the tests are shown in TABLES 9 and 10 below.
A summary of the results of the experiments is shown in TABLE 11 on
Based on the foregoing experiments, one of ordinary skill in the art would understand and appreciate that:
As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.
This application claims priority to U.S. Provisional Patent Application No. 63/599,218, filed on Nov. 15, 2023, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63599218 | Nov 2023 | US |
