Improvements in and relating to bleach dispensing systems

Abstract

A bleach dispensing system comprising: a sodium hypochlorite generator; a diluent storage; and a dispenser in fluid communication with the sodium hypochlorite generator and, wherein sodium hypochlorite from the sodium hypochlorite generator and diluent from the diluent storage are combinable to provide a bleach solution, the dispenser being configured to dispense the bleach solution in a predetermined volume of 200 mL- 5 L and to automatically terminate dispensing of the bleach solution when the predetermined volume is dispensed.

Description

[0001] Improvements in and Relating to Bleach Dispensing Systems

[0002] Field of the Invention

[0003] The present invention relates to bleach dispensing systems and to methods of operating the same.

[0004] Background to the Invention

[0005] The Covid-19 pandemic created a surge in demand for a number of healthcare related products. One such product is dilute sodium hypochlorite, commonly referred to as “bleach” or “liquid bleach”. According to World Health Organisation guidelines a 0.15% by volume (1500 PPM) bleach solution (sodium hypochlorite in water) is recommended forwipe down applications (“Cleaning and disinfection of environmental surfaces in the context of COVID-19”; WHO / 2019- nCoV / Disinfection / 2020.1).

[0006] Bleach is available in a number of concentrations. Commercially available bleach for industrial or potable water treatment applications can be in the range of 10-14%. This is normally diluted for use in these processes which are high-volume applications and is a specialist application. Bleach available for general public use is typically 5% or less and is used in homes etc by basic dilutions (around 5 to 10:1) for general disinfection of surfaces.

[0007] In environments in which bleach wipe down applications are prevalent, such as in a hospital, school, leisure centre, factory, office, leisure facility, restaurant, cafe etc, relatively large amounts of liquid bleach can be used. Generally, such liquid bleach is acquired in containers that contain 750mL of liquid bleach. This means that sites such as these go through high volumes of such containers, resulting in significant cost, large amounts of waste and ongoing inefficiencies.

[0008] Summary of the Invention

[0009] According to the present invention in a first aspect, there is provided a bleach dispensing system comprising: a sodium hypochlorite generator; a diluent storage; and a dispenser in fluid communication with the sodium hypochlorite generator and, wherein sodium hypochlorite from the sodium hypochlorite generator and diluent from the diluent storage are combinable to provide a bleach solution, the dispenser being configured to dispense the bleach solution in a predetermined volume of 200 mL- 5 L and to automatically terminate dispensing of the bleach solution when the predetermined volume is dispensed.

[0010] Suitably, the bleach concentration is of a predetermined concentration. The predetermined concentration may have a concentration of up to 0.7% sodium hypochlorite to diluent. Alternatively, the predetermined concentration may have a concentration up to 1 .25% sodium hypochlorite to diluent. Suitably, the system is configured whereby the predetermined bleach concentration can be adjusted.

[0011] Suitably, the system further comprises a low salt level detector configured to emit an alert if a low salt level is detected.

[0012] Suitably, the system further comprises a reader for detecting a user identity device, whereby the system is configured only to operate when a user identity device has been read and identified as that of a user.

[0013] Suitably, the dispenser comprises a container reader for detecting a machine-readable identifier on or in the container and the dispenser is configured to only operate upon detection of the machine-readable identifier. The machine-readable identifier may be a barcode or QR code, typically.

[0014] Suitably, the system further comprises a bleach container proximity sensor, whereby the system is configured only to dispense bleach solution when a bleach container is detected by the bleach container proximity sensor.

[0015] Suitably, the system further comprises a flow switch for monitoring flows into the bleach container. Suitably, the flow switch comprises a flow sensor and is configured whereby the flow sensor is flushed by the flow of diluent. Suitably, the system is configured to dispense diluent past the flow sensor after dispensing of the bleach fluid is terminated for each dosage. Suitably, a single flow sensor measures the flow of both bleach fluid and diluent.

[0016] Suitably, the system further comprises a scent dispenser configured to dispense a scented additive into the bleach solution.

[0017] Suitably, the system further comprises a surfactant dispenser configured to dispense a surfactant into the bleach solution. Suitably, the surfactant is combined with the diluent then added to the bleach solution. A single dispenser may contain both the scented additive and the surfactant. According to the present invention in a second aspect, there is provided a method of operating a bleach dispensing system according to the first aspect of the present invention, which method comprises dispensing bleach solution from the dispenser.

[0018] Brief Description of the Drawings

[0019] The present invention will now be described, by way of example only, with reference to the accompanying drawings; in which:

[0020] Figure 1 is a schematic illustration of a bleach dispenser installation incorporating a bleach dispensing system according to an embodiment of the present invention;

[0021] Figure 2A is a schematic front view of a bleach dispenser of Figure 1 ;

[0022] Figure 2B is a schematic side view of the bleach dispenser of Figure 2A;

[0023] Figure 3 is a schematic overview illustration of the components of a bleach dispensing system according to an embodiment of the present invention;

[0024] Figure 4 is a process and instrumentation diagram showing the components and functional operation of the bleach dispensing system of Figure 1 ; and

[0025] Figure 5 is a flow diagram illustrating a method of operation of the bleach dispensing system.

[0026] Description of the Preferred Embodiments

[0027] Referring to Figure 1 of the accompanying drawings, there is shown a building 100, in this case illustrated as a part of a hospital, the building comprising a number of rooms, in this case including wards 102A and 102B. Each ward 102A and 102B includes a bleach dispenser station 104A, 104B according to the present invention. The bleach dispenser stations 104 are in fluid communication with a water source 106, typically a mains supply. The bleach dispenser stations 104 are shown as wall-mounted units, but can be located in alternative locations, such as floor mounting or free-standing. Power is provided to the system by external mains supply (not shown).

[0028] Referring to Figures 2A and 2B of the accompanying drawings, there is shown a bleach dispenser station 104 according to an embodiment of the present invention. Each bleach dispenser station 104 comprises a housing 200, a bleach container platform 202 and a bleach dispensing tube 204. Also shown is a bleach container 206 into which the bleach dispensing tube 204 is inserted as described in more detail below. A reader 208 is mounted on the exterior of the housing 200. A display screen 210 is disposed on the front of the housing 200. A water inlet 212 is provided on one side of the housing 200. A salt loading chute 214 is provided on the other side of the housing 200 to the water inlet 212.

[0029] In an alternative embodiment, the dispensing tube 204 may be replaced by a pressure Venturi, which can help ensure that a homogeneous solution is obtained.

[0030] The bleach container platform 202 is mounted within a dispensing cavity 216 within the housing 200. An interlocked splashguard (not shown) is provided to block off the dispensing cavity 216 when sodium hypochlorite is being dispensed.

[0031] Referring to Figure 3 of the accompanying drawings, there is shown schematically a bleach dispensing system 300 comprising a bleach generator 302, one of the bleach dispensing stations 104 and a vent system 304.

[0032] The bleach generator 302 comprises a water storage tank 306 in which is included a salt container 308. Bleach generator 302 further comprises a sodium hypochlorite generator 310. Lines connecting the components in Figure 3 show fluid communication therebetween, typically via plastic pipework.

[0033] Referring to Figure 4 of the accompanying drawings, there is shown a process and instrumentation diagram corresponding to the schematic diagram of Figure 3.

[0034] The bleach dispensing system 300 comprises a connector 400 to connect the bleach dispensing system 300 to a mains water supply (not shown) via a pressure reducing valve 402. The connector 400 feeds to the water storage tank 306. Included in the water storage tank 306 is a brine tank 404 incorporating a salt block 406 and a salt proximity sensor 408.

[0035] The water storage tank 306 is in fluid communication with the sodium hypochlorite generator 310 via a first Venturi induction tee 410. The brine tank 404 is also in fluid communication with the sodium hypochlorite generator 310 via the first Venturi induction tee 410.

[0036] The venting system 304 comprises an air vent fan 412, an air flow sensor 414 and a second Venturi induction tee 416. In Figure 4, the bleach container 206 is shown mounted in a bleach container platform 202 (see Figure 2). The bleach container 206 has the bleach dispensing tube 204 located within its inlet. A proximity sensor 418 detects the presence or absence of the bleach container 206.

[0037] In Figure 4 there is further shown a combined scent additive and surfactant container 419. Although shown as a single container, the scent additive can be provided in a separate container from the surfactant. A bleach solution will disinfect but, of itself, will not clean effectively. The addition of a surfactant means that the dispensed solution can act as a combined disinfectant and cleaner. The scent additive enhances the aroma during and after application for users and others. The dosing of surfactant and / or scent is facilitated by a dedicated dosing pump 421 .

[0038] Additional components within Figure 4 are identified in Table 1 below:

[0039] TABLE 1

[0040] Referring to Figure 5 of the accompanying drawings, there is illustrated a method of operation of the dispensing system 300.

[0041] The dispensing process is initiated by a user identity device 436 being presented to the reader 208 in step 500. The user identity device 436 can be any machine-readable identity device, such as an RFID tag, a picture ID, a QR code, a mobile phone or anything similar. The reader 208 is a corresponding detection / reading device. In a preferred embodiment, the user identity device is a proximity card incorporating an RFID tag and the reader 208 is a FOB reader. Once an operator user identity device has been detected, the bleach dispensing system 300 will display instructions to the operator to define the sequence of dispensing and start function specific countdown timers. In the absence of a recognised user identity device, the system will not dispense. Alternatively, or in addition, a reader 208 may require a machine-readable identifier to be present on the container, typically a bar-code or QR code, for the dispenser to operate.

[0042] In step 502 the bleach container 206 is placed into the bleach container platform 202. The presence of the bleach container 206 on the bleach container platform 202 is detected by the proximity sensor 418. In the absence of the detection of the bleach container 206 by the proximity sensor 418, bleach dispensing will not commence. Bleach dispensing tube 204 is located within the inlet of the bleach container 206.

[0043] When, in combination, the bleach container 206 is detected in position by the proximity sensor 418 and the user identity device 436 is detected by the reader 208, the splashguard is deployed to prevent excess bleach being ejected into a potentially occupied area during dispensing.

[0044] In step 504 dosing to the bleach container 206 is commenced. To control dispensing and ensure repeatability of chemical dosing, primary dosing to the bleach container 206 is made by the dosing pump 426. To dose a controlled volume of sodium hypochlorite, while dosing the flow switch 424 monitors flow of liquid into the bleach container 206 using a flow sensor 425. Once a controlled volume of sodium hypochlorite is dosed, the softened water dispensing solenoid 430 opens to fill a controlled volume of softened water into the bleach container 206. Once again, the flow switch 424 monitors flow into the bleach container 206. The flow switch 424 is configured to be flushed by the softened water to ensure crystallisation of the sensor incorporated in the flow 424 does not take place. Advantageously, a single flow sensor 424 is used constantly to monitor the correct flow of both the diluent water and concentrated bleach fluid to ensure the correct concentration of final product.

[0045] In a preferred embodiment, prior to dispensing to the container 206, the hypochlorite dosing pump 426 is engaged for a first predetermined time (typically 2 seconds) and flow monitor that the flow switch 424. Hypochlorite dosing is then paused, and softened water dosed for a second predetermined time (typically 2 seconds) and the flow monitored again at the flow switch 424. Once flow of both hypochlorite and softened water has been confirmed, both pumps resume for a third and fourth period of time respectively. That is, the hypochlorite pump is dosed for the third period of time and the softened water pump is dosed for the fourth time period. The fourth time period is set to be longer than the third time period to flush the flow switch 424. Typically, the third time period is 11 seconds and the fourth time period 13 seconds. Throughout the entire dosing process, the proximity sensor 418 ensures the bleach container 206 remains in position. Removal of the bleach container 206 or failure of the sensor will result in the filling operation pausing. A filling timer runs during the dosing process. If the filling timer elapses, the dosing operation is reset.

[0046] Once the bleach container 206 has been loaded into position, a predetermined volume of bleach solution is dispensed into the bleach container 206. Currently, the predetermined volume to be dispensed is preferred to be 750 mL. However, the predetermined volume to be dispensed can vary and be varied according to device settings. The predetermined volume can have a lower limit of any of 400 mL, 300 mL or 200 mL. The predetermined volume can have an upper limit of any of 600 mL, 700 mL, 800 mL, 900 mL,1000 mL or 5000mL (i.e. 5 L). Any combination of the upper and lower limits for the predetermined volume is possible and can be adjusted in a system processor and optionally programmed into the fob reader.

[0047] The sodium hypochlorite and diluent is dispensed to provide a controlled strength of 0.15% or 1.5 g / L of sodium hypochlorite to diluent.

[0048] The preferred diluent is water and can simply be water from the mains supply. Provision is made for additional softening of the supplied water if required.

[0049] Step 504 can include the additional dosing of a scent additive and / or a surfactant into the bleach solution from the container 419. When used, the surfactant is combined with the diluent then added to the bleach solution. A user can control whether the scent additive and / or surfactant is dispensed.

[0050] In step 506, when the predetermined volume of liquid bleach has been dispensed, the dispensing operation is terminated and a suitable indication is provided to the user. Typically, the indication will be one or both of a visual or audible signal. The bleach container 206 can then be removed from the bleach container platform 202 and used.

[0051] Further details are now provided regarding the generation of sodium hypochlorite locally within the bleach dispensing system.

[0052] The sodium hypochlorite is evolved from the electrolysis of a brine solution in an inline monopolar electrolytic cell constructed from titanium anodes and coated titanium cathodes in upVC cell with clear acrylic cover. The cathodes are coated with a Mixed Metal oxide coating derived from iridium and ruthenium. The electrolytic cell is a dual chamber sodium hypochlorite is generated in the first chamber, and weirs into the second chamber, which has a dual purpose. The second chamber acts as a storage vessel and degassing vessel where evolved hydrogen can degas from the sodium hypochlorite solution. The hydrogen gas is allowed to exit the second chamber from a port where is mixed with air and released to atmosphere.

[0053] On receiving a demand signal from the sodium hypochlorite generator 310, water flow to the generator is initiated at the water feed control solenoid valve 432. The water feed control solenoid valve 432 opens and allows regulated mains pressure, via the pressure reducing valve 402 through the water softening cartridge 428 treating the water. Softened water is automatically fed to the small volume integral brine tank 404 via the automatic float valve 438. In a preferred embodiment, the brine tank 404 is sized for a single 4 kg salt block. The float valve 438 is positioned and configured to remove the possibility of overflowing the tank when salt is loaded.

[0054] The first Venturi induction tee 410 in the softened water feed line draws brine from the brine tank 404 and mixes the drawn brine before entering the sodium hypochlorite generator 310. The brine line is fitted with a foot valve offering salt particle filtration and a check valve to keep the brine line primed, and to ensure dilution of softened water and brine into the sodium hypochlorite generator 310.

[0055] The integral salt level proximity sensor 408 is fitted within the brine tank 404 to detect a low salt level within the brine tank 404. The brine tank 404 is also fitted with a salt block loading chute (not shown) to ensure correct loading of salt blocks.

[0056] Upon initiation of flow at either the water feed solenoid valve 432 or the brine tank float valve 438 water under mains pressure will flow directly through the water softener cartridge 428 ensuring all water used in the system is correctly softened.

[0057] A watchdog on time system on both the hypochlorite dosing pump 426 and the softened water control valve 432 records the total operating flow of each to calculate a total softened water flow volume and a total brine flow volume. These values are used to prompt the operator on the remaining operating hours before salt needs to be refilled all water softener cartridges 428 need to be replaced. Volumetric flow calculators can then be reset automatically by the salt level proximity sensor 408 in the brine tank 404, which will also interlock the system when salt has run out, and manually by a service engineer on successful replacement ofthe water softener cartridge 428.

[0058] The system is fitted with an integral chemical and scratch resistant polypropylene bund 434 fitted with a bund flood alarm (not shown) to detect any leaks within the system. If any leakages are detected, an alarm is emitted. On a falling degassing tank signal, electrolyte flow into the electrolytic cell is introduced, naturally forcing the already generated sodium hypochlorite in the electrolytic cell to the vent system acting as a degassing column. Once a degassing tank full signal is detected the system interlocks the flow of electrolyte into the cell and applies DC power across the cell for 90 seconds. Once the generation time has elapsed, the interlock on the electrolyte flow is removed and the generation cycle is completed. The degassing tank is also fitted with a low level switch 422 to inhibit dosing that tank low level, to prevent air locking of the dosing pump and ensuring the electrolytic cell is completely submerged at all times.

[0059] Immediately on introduction of DC power to the cell, the air ventilation fan is initiated ensuring the DC cell power supplies consistently cooled. The airflow exits the control enclosure at high level and via a Venturi induction to the draws the generated hydrogen from the electrolytic cell and dilutes it to 1 :10 of the hydrogen lower explosive limit before exiting the system.

[0060] Accordingly, according to preferred embodiments of the present invention, a self- contained bleach dispensing system is provided which can dispense relatively low volumes of bleach solution into a suitably sized bleach container on demand. The bleach dispensing system is self-contained, requiring only a water supply connection and the occasional refilling of consumables.

[0061] Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0062] At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as ‘component’, ‘module’ or ‘unit’ used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.

[0063] Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of others.

[0064] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0065] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0066] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0067] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims1 . A bleach dispensing system comprising: a sodium hypochlorite generator; a diluent storage; and a dispenser in fluid communication with the sodium hypochlorite generator and, wherein sodium hypochlorite from the sodium hypochlorite generator and diluent from the diluent storage are combinable to provide a bleach solution, the dispenser being configured to dispense the bleach solution in a predetermined volume of 200 mL- 5 L and to automatically terminate dispensing of the bleach solution when the predetermined volume is dispensed.

2. A bleach dispensing system according to claim 1 , wherein the bleach concentration is of a predetermined concentration.

3. A bleach dispensing system according to claim 2, wherein the predetermined concentration is of up to 0.7% sodium hypochlorite to diluent or 1.25% sodium hypochlorite to diluent.

4. A bleach dispensing system according to any preceding claim, wherein the system is configured whereby the predetermined bleach concentration can be adjusted.

5. A bleach dispensing system according to any preceding claim, wherein, the system further comprises a low salt level detector configured to emit an alert if a low salt level is detected.

6. A bleach dispensing system according to any preceding claim, wherein the system further comprises a reader for detecting a user identity device, whereby the system is configured only to operate when a user identity device has been read and identified as that of a user.

7. A bleach dispensing system according to claim 6, wherein the dispenser comprises a container reader for detecting a machine-readable identifier on or in the container and the dispenser is configured to only operate upon detection of the machine-readable identifier.

8. A bleach dispensing system according to claim 7, wherein the machine-readable identifier is a barcode or QR code.

9. A bleach dispensing system according to claim 1 , wherein the system further comprises a bleach container proximity sensor, whereby the system is configured only to dispense bleach solution when a bleach container is detected by the bleach container proximity sensor.

10. A bleach dispensing system according to any preceding claim, wherein the system further comprises a flow switch for monitoring flows into the bleach container.11 . A bleach dispensing system according to claim 10, wherein the flow switch comprises a flow sensor and is configured whereby the flow sensor is flushed by the flow of diluent.

12. A bleach dispensing system according to claim 1 1 , wherein the system is configured to dispense diluent past the flow sensor after dispensing of the bleach fluid is terminated for each dosage.

13. A bleach dispensing system according to claim 1 1 or claim 12, wherein a single flow sensor measures the flow of both bleach fluid and diluent.

14. A bleach dispensing system according to any preceding claim, wherein the system further comprises a scent dispenser configured to dispense a scented additive into the bleach solution.

15. A bleach dispensing system according to any preceding claim, wherein the system further comprises a surfactant dispenser configured to dispense a surfactant into the bleach solution.

16. A bleach dispensing system according to claim 15, wherein the surfactant is combined with the diluent then added to the bleach solution.

17. A method of operating a bleach dispensing system according to any one of claims 1-16, which method comprises dispensing bleach solution from the dispenser.

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