TECHNICAL FIELD

The present invention relates to devices and methods for reducing the risk of cross contamination and disease propagation by hand contact with door handles.

BACKGROUND OF THE INVENTION

Door handles are probably among the objects that contribute the most to the dissemination of microbes by direct contact. The danger of cross contamination through contact with a door handle is particularly great in public places, for example in public toilets, hospitals, offices of medical practitioners, hotels, restaurants and coffee shops. A person gripping a door handle inevitably leaves behind on the handle and, possibly, the door rosette (a flat object that is mounted to a door and that has an opening through which the door handle is attached to the door) some of the microbes that are present on its hand. This is not only occurring if the person has not properly washed its hands prior to the contact with the door handle. Even washing using soap will not remove all microbes from the hands. A door handle that has been contaminated by a first person will be a source of contaminating microbes for the second person gripping the door handle. In this way, microbes are spread among large numbers of persons opening or closing the respective door. One might think that the danger of picking up microbes by contact with a contaminated door handle is particularly important when the contaminating microbes are bacteria or fungi, because these organisms are typically capable of persisting outside of their normal host or environment. However, even viruses are known to survive for considerable periods of time. The problem is exacerbated if the door handles contain crevasses and cracks that can be infiltrated by microbes and that thereby become more difficult to decontaminate.

Methods of sterilization of surfaces are well known in the art and are used routinely, e.g., in medical treatment rooms, operating theatres, food or drug production lines, etc. Methods used in the medical area include sterilization by autoclave, steam, flash, dry heat, moist heat and irradiation. Irradiation can be by ionizing radiation (e.g., gamma radiation) or by nonionizing radiation (UV). In cases where use of heat or radiation is not indicated, sterilization can be achieved by means of chemicals, used either in liquid or gaseous form. Frequently used chemical sterilants/high level disinfectants include ethylene oxide, nitrogen dioxide, ozone, glutaraldehyde or formaldehyde, hydrogen peroxide and peracetic acid. Perhaps, the most commonly used disinfectant is isopropyl alcohol (2-propanol). While often used as 91 + % isopropanol, it is considered to be more effective when used as 70% isopropanol, primarily because of the reduced rate of evaporation and the resulting extended exposure time of microbes. Isopropanol (70%) is also commonly used in alcohol-based hand rubs. Alcohols including isopropanol are known to be highly effective against mycoplasmas, gram-positive and gram-negative bacteria, including pseudomonads, rickettsiae and chlamydiae). They are also effective against acid-fast bacteria (which include mycobacteria such as Mycobacterium tuberculosis), enveloped viruses (that include influenza- and herpesviruses) and fungal spores. Other commonly used disinfectants are biguanides, halogens, phenolic compounds and quaternary ammonium compounds.

Short-wavelength ultraviolet light (UV-C) is absorbed by the DNA or RNA of microbes, causing damage to the nucleic acids, e.g., by dimer formation. As a result, the irradiated microbes become incapable of replicating. The wavelengths responsible for these effects are between 240 and 280 nanometers (nm), with a DNA absorption peak at 253.7 nm.

In air and surface disinfection applications, the UV effectiveness is estimated by calculating the UV dose which will be delivered to the microbial population. The UV dose is calculated as follows:

UV dose pWs/cm ² = UV intensity pW/cm ² x Exposure time (seconds)

The UV intensity is specified for each lamp at a distance of 1 meter. UV intensity is inversely proportional to the square of the distance so it decreases at longer distances. Alternatively, it rapidly increases at distances shorter than 1 m. In the above formula the UV intensity must always be adjusted for distance, unless the UV dose is calculated at exactly 1 meter from the lamp.

The destructive effects on microbes are dependent on the exposure dose: No/N = (0.1 ) ^D/K , whereby No is the number of microbes after treatment, N is the initial number of microbes targeted, K is a constant related to the type of microbe targeted, and D is the dose. A single dose will have a destructive effect of 90%, a double dose of 99% and a triple dose of 99.9%. Dosages for a 90% kill of most bacteria and viruses range from 2,000 to 8,000 pW-s/cm ² .

Suitable UV-C sources are

- Mercury-based lamps emitting UV light at the 253.7 nm line,

- Ultraviolet light-emitting diodes (UV-C LED) lamps emitting UV light at selectable wavelengths between 255 and 280 nm, and

- Pulsed-xenon lamps emitting UV light across the entire UV spectrum with a peak emission near 230 nm. Mercury-based lamps powered from about 120W to about 200W would be well suited for the disinfection of door handles, because the surface area of an average handle is about 100cm ² . The required degree of disinfection would be reached after one second of exposure.

SUMMARY OF THE INVENTION

The present disclosure relates to a device for the automatic disinfection of a door handle and a door rosette. The device comprises (a) a disinfection unit that when activated is capable of disinfecting the door handle, (b) a sensor that detects when the door handle is gripped and released, and (c) a controller that receives signals from the sensor and responds at least each time a user’s hand has been released from the door handle by optionally positioning the disinfection unit over the door handle, activating the disinfection unit, disactivating the disinfection unit after disinfection has been achieved and optionally returning the disinfection unit to its original position. The device is capable of being mounted on a door such that access to the door handle is unimpeded. Furthermore, the device is compact and of sufficiently light weight to not exert undue structural strain on door, hinges and frame. Moreover, the device is capable of carrying out at least 2,000 disinfection cycles without maintenance. The devices described for disinfection of a door handle can also advantageously be used for disinfection of any other door opening mechanisms or modalities that are actuated by a user such as door knobs.

A first type of device of the present disclosure comprises a housing that is mounted on the door adjacent to the door handle and is open or openable on the side proximal to the door handle. The disinfection unit contained in the housing comprises (a) a hollow-core UV-C lamp defining an interior irradiation chamber, whereby the UV-C lamp is indented so that it is capable of sliding over and past the door rosette, (b) a protective envelope for the UV-C lamp shaped to follow the contours of the UV-C lamp, (c) an interior wall shaped to surround the protective envelope and (d) a mechanism for laterally displacing the UV-C lamp and the protective envelope though the open end of the housing to position the UV-C lamp over the door handle and the door rosette. The controller controls the displacement of the UV-C lamp and the protective envelope as well as the operation of the UV-C lamp.

In a particular embodiment of the first type of device, the UV-C lamp is a cylindrical arrangement of multiple UV-C lamps.

In another particular embodiment of either of the latter devices, the mechanism for laterally displacing the UV-C lamp and the protective envelope (which elements move together and are also referred to as“UV-C lamp/protective envelope assembly”) comprises one or more screw slides that are mounted in the space between the interior wall and the protective envelope, and one or more micromotors that are engaged on the screw slides and are capable of effecting the lateral displacement.

The latter devices can be used in conjunction with a standard-sized door handle having a tubular shape and a polished surface and a standard-sized rosette having a polished surface. They can also be used in conjunction with a reflective walled cover that is mounted on the door on the device-distal side of the door handle and that abuts the end of the UV-C lamp when the lamp is positioned over the door handle and the door rosette. The reflective walled cover serves to prevent UV-C light emitted by the end of the UV-C lamp from escaping into the surroundings. The same purpose may be served by an openable shutter that is mounted in a terminal position on the protective envelope surrounding the UV-C lamp (i.e., a position that comes to lie behind the door handle assembly in the fully extended state of the UV-C lamp/protective envelope assembly). Consequently, the shutter is capable of being closed behind the door handle and the door rosette. The devices can further comprise a case detector integrated in the quartz glass of the UV-C lamp and/or an unlocking feature allowing manual lateral displacement the UV-C lamp/protective envelope assembly.

A second type of device of the present disclosure comprises a housing that defines an open space in its interior which open space is sufficiently large to accommodate the door handle and the door rosette, the housing being mounted on the door such that the door handle and the door rosette come to reside in the open space. The disinfection unit that is contained in the housing comprises (a) a reservoir for holding a disinfection solution, (b) one or more nozzles integrated in or mounted on a wall of the housing which wall defines the top of the open space, the nozzles having orifices protruding into the open space above the door handle and the door rosette and pointing downward towards the door handle and the door rosette, and (c) a pump that is connected by tubing to the reservoir and to the one or more nozzles. The controller controls the operation of the pump. In certain embodiments, the controller not only activates the disinfection unit each time the user’s hand has been released from the door handle but also each time the user’s hand grips the door handle.

In a particular embodiment of a device of the second type, the disinfection unit further comprises one non-return valve for each nozzle, the non-return valve being inserted/mounted adjacent to the nozzle in the tubing connecting the pump and the nozzle.

The disinfection solution used in the latter devices (referring to devices of the second type) can be an alcoholic solution. The most preferred disinfection solution is Sterillium.

The accessible front of the housing of the latter devices comprises or consists of a door that provides access to all components of the disinfection unit. Typically, a removable tray is provided at the bottom of the open space, i.e., below the door handle and the rosette that are sprayed with disinfectant. The tray serves to collect excess disinfection solution. Above the tray can be mounted a perforated grill through which excess disinfection solution passes before reaching the tray. In some embodiments, one or more sensors are provided for detecting when the reservoir is in need of refilling. As an alternative, a transparent window in the housing door in conjunction with a transparent reservoir will allow visual inspection of the level of disinfection solution in the reservoir.

Also encompassed is the use of the devices of this disclosure for the automated disinfection of a door handle and its door rosette.

BRIEF DESCRIPTION OF FIGURES

Fig.1 illustrates a device for UV-C-mediated disinfection of a door handle of the first type of embodiment showing the UV-C lamp/protective envelope assemby in the standby position.

Fig.2 illustrates the device of Fig.1 but with the UV-C lamp/protective envelope assembly shown in the fully extended (working) position. The front end of the UV-C lamp is protected by a walled cover that is affixed to the door on the device-distal side of the door handle.

Fig.3 illustrates another embodiment of the device in which the front end of the UV-C lamp is protected by a shutter.

Fig.4 illustrates a device for chemical disinfectant-mediated disinfection of a door handle of the second type of embodiment, the device having been properly mounted on a door.

Fig.5 provides a frontal view of the device of Fig.4 (with housing door removed).

Fig.6 provides a frontal view of aspects of the device of Fig.4 (with housing door removed).

Fig.7 provides a view from below of aspects of the device of Fig.4.

Fig.8 provides a perspective view of aspects of the device of Fig.4 (with aspects of the housing removed).

Fig.9 shows a frontal view of the device of Fig.4.

Fig.10 provides a view from below of a particular mounting of nozzles. DETAILED DESCRIPTION OF THE INVENTION

The aim of the present disclosure is to provide devices and methods for the disinfection of door handles so as to prevent contact transmission of microbes from one person to another. The devices share the following features or properties:

1. The device is capable of being mounted on a door in such a way that a person is not impeded in actuating the door handle to be disinfected by the device.

2. The device is compact and of a weight that does not affect the proper operation of a standard door on which it is mounted, i.e., no undue strain is exerted on door, hinges or frame.

3. The device is capable of disinfecting the nearby door handle after each actuation of the door handle (as well as, in some embodiments, during each actuation of the door handle).

4. The device comprises a disinfection unit that is capable of disinfecting the door handle when activated.

5. The device comprises a sensor that detects when the nearby door handle is gripped and released.

6. The device comprises a controller that receives signals from the sensor and activates the disinfection unit each time a user’s hand has been released from the door handle as well as disactivates the disinfection unit after disinfection is achieved. In some embodiments, the controller also activates the disinfection unit each time a user’s hand grips the handle. Depending on device configuration, the controller may also operate a mechanism that moves the disinfection unit from a standby position into a working position over the door handle and back.

7. The device is designed for autonomous operation. No maintenance is required prior to the completion of at least 2,000 disinfection cycles.

8. There are no impediments to the mass manufacture of the device.

9. When mass-produced, the cost of production of the device is preferably below about USD 1 ,000 per device and more preferably below about USD 500 per device.

A first type of embodiment of a device of the present disclosure employs UV-C light to disinfect. Reference is made to Figs. 1-3. The device comprises a housing (6/7) that is mounted on the door (21 ) on a level with and at an appropriate distance from the door handle to be disinfected (14). The housing contains a UV-C tubular lamp (1 1 ) covered by an external protection (10) (Fig.1 ). The UV-C tube and its protection can be caused to slide out of the housing to cover the door handle. Fig.2 shows the fully extended position. In this position the UV-C lamp is turned on to effect disinfection of the door handle. To ensure uniform effectiveness of disinfection the device is preferably used in conjunction with a door handle of standard dimensions and surface properties (which is mounted on the door in lieu of the previously installed handle). Subsequent to irradiation of the door handle, the UV-C tube and its protection are caused to slide back into the housing, attaining the position shown in Fig.1.

In more detail, the example device comprises a housing (6/7). The lamp compartment (7) comprises three tubular structures:

a UV-C lamp (1 1 )

a protective envelope of the UV lamp (10) and

an internal space (8) formed by a cylindrically shaped interior wall of the lamp compartment, which internal space surrounds the protective envelope.

Mounted in the internal space (8) are screw slides (5) that enable a lateral movement of the UV lamp (1 1 ) and its envelope (10) towards and from the door handle (14). In other embodiments, only one or more than two screw slides may be installed. Other equivalent means for enabling the lateral movement of lamp and envelope are encompassed in this disclosure.

The protective envelope of the UV lamp (10) is made of material that is impenetrable by UV light.

The UV lamp that is cylindrical in shape forms an irradiation chamber in its interior (13). Other designs would be feasible, e.g., an array of multiple lamps may be employed that are arranged to delimit an irradiation chamber.

The UV lamp (1 1 ) and its envelope (10) have at their door handle-proximal end (front end) a carve-out (12) that is adapted to the dimensions of the bent portion of the handle and the rosette (17), allowing the UV lamp/protective envelope assembly (10,11 ) to fully cover the entire handle and assembly in its fully extended position. The lamp may be of any suitable type, e.g., a low-pressure mercury lamp, an LED lamp or a pulsed xenon lamp. The lamp may be a single unit or a plurality of units/elements combined together.

The support bars (3) are secured to the UV lamp/protective envelope assembly (10,11 ) and allow its movement along the screw slides (5). The screw slides (5) are anchored in the end wall of the technical housing (6). A micromotor (1 ) is engaged on each screw slide (5). The two motors (1 ) are connected by a connecting bar (4) allowing synchronization of their movement along the screw slides (5). The motors (1 ) may or may not be integrated with or attached to the support bars (3). Other embodiments may employ only a single motor in combination with synchronization means to ensure coordinate movement of the UV lamp/protective envelope assembly (10,11 ) along the screw slides. It is noted that the lateral displacement of the UV lamp/protective envelope assembly (10,11 ) may be achieved by other means, e.g., by belt, rack, or pneumatic mechanism.

In the case the support bars (3) are integrated with or attached to the motors (1 ), the motors will move together with the UV lamp/protective envelope assembly (10,11 ) along the screw slides (5). The support bar (3) and the connecting bar (4) are attached to one another. If the two types of bars are not attached to one another, the motors (1 ) connected by the connecting bar (4) will remain in the technical housing (6), and lateral movement of the UV lamp/protective envelope assembly (10,11 ) is driven by the support bars (3) that are actuated by the screw slides (5).

The technical box (6) comprises a controller that receives signals from a sensor (19) that recognizes the presence or absence of a hand on the door handle (14), the sensor being any suitable sensor including an ultrasound-based sensor.

When the sensor signals that a hand has been removed from the handle, the controller activates the motors (1 ) to move the UV-C lamp/protective envelope assembly into its fully extended position,

activates and deactivates the UV-C lamp(s) in the fully extended position, and

reactivates the motors to retract the UV-C lamp/protective envelope assembly and return it to its standby position (lamp completely residing in the housing).

It is noted that the UV-C irradiation may be for a predetermined period of time. The preferred length of irradiation is between 1 and 10 seconds. Most preferred is an exposure time of one second. Alternatively, irradiation time may be made dependent on the level of contamination of the door handle. A fluorescence sensor may be employed to assess the level of contamination.

A protective walled cover (15) is used to cover the front end of the UV-C lamp (1 1 ) during its operation. This cover is mounted on the door on the device-distal side of the door handle and is intended to minimize the amount of UV-C light that escapes to the surroundings. The handle-proximal surface of the cover (16) is reflective and redirects UV-C light to the bent parts of the handle (14), optimizing disinfection efficiency.

The standard handle (14) used in conjunction with the device is preferably of solid tubular shape and has a polished surface to reduce as much as possible the surface to be disinfected. The rosette (17) preferably has a polished surface as well.

The device may contain additional useful features such as a case detector in the quartz glass of the UV lamp that makes it possible to monitor the operating efficiency of the lamp,

a manual unlocking system that is useful in the case of a mechanical failure in which the UV- C lamp/protective envelope assembly remains blocked in the fully extended position, and a shutter (24) that may be employed to prevent radiation emitted from the front end of the UV-C lamp to escape to the surroundings (Fig.3). This shutter may be employed instead of the walled cover (15) that is depicted in Figs. 1 and 2. The shutter may be operated manually, or by an electromechanical or pneumatic mechanism.

It is noted that the device as presented in the above description stipulates a horizontal displacement of the UV-C lamp/protective envelope assembly. The present disclosure also encompasses embodiments in which the latter displacement is vertical, which may be advantageous for certain door opener configurations.

The device operates as follows:

The device is in its (retracted) standby position. Sensor (19) senses that a person has released the door handle and transmits this information to the controller. The controller activates the motors (1 ) that drive the UV-C lamp/protective envelope assembly to its fully extended position in which the UV-C lamp is positioned over the door handle assembly and abutting the walled cover. The controller then turns on the UV-C lamp. After the time required for disinfection (e.g., the time needed to reduce the bacterial count by 4 log scales), the controller turns off the lamp and reactivates the motors that retract the UV-C lamp/protective envelope assembly back into the housing (7) until it has reached its standby position.

The device has several advantageous technical features:

Long operational life (about 4,000 hours)

The short duration of the irradiation cycles translates into low operating costs and long maintenance intervals.

No cooling is necessary when a low-pressure UV-C lamp is used.

Integrated case detector in quartz glass monitors UV-C lamp performance, ensuring proper disinfection.

The requirements of international protection class IP55 can be met.

Easy and precise installation of device and matching handle. Plug-in UV-C lamp is easily replaced.

Small size and small cost of manufacture of the device.

A second type of embodiment of a device of the present disclosure employs a chemical disinfectant to disinfect a door handle and its rosette. Reference is made to Figs. 4-9. Many different disinfectants can be dispensed by this type of device. Preferred are alcohol-based disinfectants. Most preferred is a disinfectant solution known as Sterillium, which product has been extensively used in hand rubs and for the disinfection of medical treatment rooms, laboratories, etc. Steillium which is commercially available comprises 45 g of isopropanol (2- propanol), 30 g of propanol (1 -propanol) and 0.2 g of quaternary ammonium compound mecetroniumetilsulfate per 100g of the composition.

The device is designed for the automated disinfection of a door handle and its rosette at least after each actuation of the door handle by means of a mist of a disinfectant solution that is sprayed onto the door handle and the rosette. Referring to Fig.4, the device is comprised of a housing (2) having an opening or space that is typically rectangular-shaped and is sufficiently large to accommodate a door handle and its rosette. The housing is mounted on a door (3) so that the door handle (1 ) including its rosette comes to reside unobstructed within the latter opening. It is noted that the device is capable of accepting door handles and rosettes of various shapes and sizes. Replacement of a door handle with a standard size handle is not required. It is further noted that, while its main function is to disinfect the door handle and its rosette, the device will also assist hand hygiene. The mist that has been sprayed on the door handle after an actuation will remain present on the door handle. The hand of next person gripping and depressing the door handle will inevitably come into contact with the residual disinfectant. Rubbing of the hands will distribute the disinfectant to both hands.

Referring to Fig.5, within the housing is found a reservoir (4) that is to hold the disinfectant solution. The reservoir that is made from a material that is resistant to the disinfectant solution used has a wide threaded neck (5) used for refilling the reservoir. The wide neck is usually covered by a lid. The reservoir additionally comprises a narrow, threaded neck (6) with a closure through which a tube (7) is inserted that connects with a pump (8). The tube is typically flexible and may be of a plastic material that is resistant to the disinfectant used. The pump can be a peristaltic pump, a diaphragm pump or any other suitable pump, the pump being powered by one or more DC batteries (14) or alternating current available at the location (e.g., 220V AC). When actuated, the pump removes disinfectant solution from reservoir (4) and pushes it against backpressure into one or more tubes (9) each of which feeds a nozzle (10). The nozzles are mounted in the bottom wall of the housing overlooking the opening such that they protrude into the opening and their orifices are directed towards the door handle and its rosette. A non-return valve (11 ) is placed in each feeding line (9), proximally to the nozzle, to prevent air intake through the nozzle and to ensure that the feeding line remains filled with disinfectant solution.

A sensor (12) is affixed to or inserted into the bottom wall of the housing overlooking the opening such that the sensor can detect whether a hand is present on the door handle. The sensor can be an ultrasonic, am infrared or a laser sensor, or any other suitable sensor. The typical position of the sensor (12) is shown in Figs.7 and 8. Sensor (12) sends its signals to a controller (13) (Fig.5). The controller is powered by one or more DC batteries (14) or alternating current available at the location (e.g., 220V AC). When receiving the appropriate signal from the sensor, the controller causes the pump to engage and operate for a predetermined duration, during which time disinfectant solution is sprayed through the nozzles onto the door handle and rosette. It is noted that the nozzles will directly spray the exposed (upper) surface of the door handle. The unexposed (lower) surface receives disinfectant solution from the exposed (upper) surface as a consequence of gravity and low surface tension. The predetermined duration is the minimal duration that results in the desired log reduction of the microbial, e.g., bacterial, count on door handle and rosette. Preferred is a reduction of the bacterial count by 4 log scales. The minimal duration is determined in appropriately powered experiments. Limiting the spray operation to the actual time required to achieve the desired decontamination effect will serve to minimize disinfectant use, battery depletion or other energy consumption and required maintenance.

The front of the housing is protected by a door (15) that typically is carried by hinges mounted on the top wall of the housing and opens upward (Fig.9). When the door is open, all components that may need to be serviced (7-12), refilled (4) or replaced (14) are freely accessible. On the bottom of the opening rests a removable tray (16) that is situated below a perforated grill (17) (Figs.5 and 9). The tray serves to collect any excess disinfection solution.

To facilitate maintenance, a liquid level sensor (e.g., an ultrasound or capacitance level sensor) may be mounted inside or outside the reservoir (4). Alternatively, the reservoir may be made of a transparent material, and device door (15) contains a window that allows visual inspection of the state of filling of the reservoir. It is noted that many of the components of the device are depicted in more than one of the views presented in Figs.5-9.

For optimal disinfection of door handles of different designs, it may be desirable to be able to adjust the position of the nozzles. In the simple arrangement shown in Fig.10, the nozzles are mounted on a nozzle holder (20) having channels (19). The nozzle holder is movably affixed by means of screws (18, 18’) to the open space-side of the housing wall overlooking the open space. When the screws are loosened, the nozzle holder can be displaced along the channels, i.e., along the y axis shown.

The device may be operated in at least two different modes. In a first mode, the device is so configured that the controller detects a sensor signal indicating that a person’s hand has been released from the door handle. With or without a delay, the controller then transiently activates the pump resulting in the dispensing of the disinfection liquid through the nozzles for the predetermined duration. In this mode, the door handle and rosette are disinfected after each actuation of the door handle. The disinfectant film remaining on the door handle also serves the hand hygiene of the next person actuating the door handle. In a second mode, the device is so configured that controller detects sensor signals indicating either that a person has gripped the door handle or that a person has released the door handle. Hence, disinfectant solution will be sprayed on the door handle after it has been released as well as on the back of a hand gripping the door handle. The sensation caused by the spraying of the hand will cause the person to rub the back of the hand in the hollow of the other hand, which will cause a disinfecting effect also on the hand that did not grip the handle.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein.

The description herein of any aspect or embodiment of the invention using terms such as reference to an element or elements is intended to provide support for a similar aspect or embodiment of the invention that“consists of,”“consists essentially of” or“substantially comprises” that particular element or elements, unless otherwise stated or clearly contradicted by context (e. g. , a device described herein as comprising particular elements should be understood as also describing a device consisting of the latter elements, unless otherwise stated or clearly contradicted by context).

This invention includes all modifications and equivalents of the subject matter recited in the aspects or claims presented herein to the maximum extent permitted by applicable law.

The example embodiments described herein are provided as illustrations of the present invention claimed and are not intended to be limiting of the present invention.