Abstract:
An ultraviolet radiation system to decontaminate small objects such as TV remote controls, hospital bed controls, cell phones, computer tablets and the like which are present in a hospital or other health care facility. The system includes a plurality of UVC lamps arranged in a table top sized housing and having a UVC transmissive shelf in the housing for support of objects to be decontaminated. The system has a microprocessor based controller and can kill  Clostridium difficile  and other pathogens to thereby decontaminate items in 30 seconds or less.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     N/A 
     BACKGROUND OF THE INVENTION 
     Hospital acquired infections can infect patients, healthcare providers and visitors in a hospital environment, and infections can be passed from one person to another by contact with contaminated fixtures, surfaces or other objects in a hospital or other healthcare facility. One product for addressing the matter of decontamination, particularly in a hospital setting, is described in U.S. Pat. No. 8,791,441 of the same inventor as the present invention. This patent shows a system for decontamination by UVC radiation of surfaces of a hospital room or other facility and of the air in the room. 
     There is a need for a convenient and cost effective manner to decontaminate small items typically found in a hospital environment such as hospital bed controls, TV remote controls, cellphones, computer tablets, and the like. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a UVC disinfection system housed in a tabletop enclosure similar in size to a toaster oven or microwave oven. A door permits access to a chamber in which small items to be decontaminated can be disposed. The system produces UVC radiation of sufficient dosage to kill pathogens including  Clostridium difficile  on the items in the chamber in a rapid, simple and reliable manner. The system in one embodiment comprises a housing containing a plurality of UVC lamps disposed at the top and bottom of the housing, a UVC transmissive shelf in the chamber for supporting items to be decontaminated and an electronic controller for control of the ballasts for the UVC lamps and for control of system operation. 
     The germicidal lamps are typically low pressure, high output mercury or amalgam lamps that have an extremely high conversion efficiency of 35% of input power to radiation at 253.7 nm (usually referred to as 254 nm). The UVC lamps are made of pure quartz designed to pass radiation at 253.7 nm but not cause ozone generation. The quartz is quite brittle and if accidently broken causes scatter of quartz particles over a wide area. To eliminate this potential problem, each lamp tube is encased in an FEP (Teflon) sleeve to contain any fragments of quartz if broken. FEP is one of the few plastics that have a very low attenuation of UVC radiation and is also unaffected by the temperature of the quartz envelope when the lamp is energized. The UVC lamps are driven by one or more electronic ballasts which can operate from a wide variety of AC power sources. In a preferred embodiment, the housing is made of aluminum with a hinged and locking front cover. A shelf of pure quartz is provided in the chamber and on which items to be decontaminated can be placed. 
     The system is controlled by an electronic controller which typically is a microprocessor based controller. The door has a locking mechanism to maintain the door in closed position and is associated with a safety switch to prevent operation of the system when the door is open. An alpha, numeric or alpha numeric display is provided on the housing to indicate time remaining for completion of a decontamination cycle and to indicate system status. Audible and/or visual indicators can also be provided to signify system conditions including error conditions if the lamps or the system are not operating properly. A single pushbutton switch is provided on a control panel to start a decontamination cycle. The pushbutton can be of the lighted type which illuminates to indicate that power is applied to the system. 
     The housing can include a side door or slot to enable wires or cords of devices being decontaminated to be threaded from outside the housing into the chamber. The wired or corded devices can be for example, a hospital telephone or hospital bed control. The side door may also have a safety switch to prevent operation of the system if the door is opened beyond a small amount necessary to accommodate the device cord. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention will be more fully understood from the following detailed description in conjunction with the drawings in which: 
         FIG. 1  is a pictorial view of one embodiment of a system in accordance with invention; 
         FIG. 2  is a diagrammatic view of a control panel of the embodiment of  FIG. 1 ; 
         FIG. 3  is a block diagram of a system in accordance with the invention; 
         FIG. 4  is an elevation view of the system illustrating an item in place for contamination; and 
         FIG. 5  is an elevation view of the system with a corded item in place for decontamination. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One embodiment of a UVC disinfection system in accordance with the invention is shown in  FIG. 1 . A housing or enclosure  10  contains a plurality of UVC lamps  12  at the top and bottom of a chamber  14 . In the illustrated embodiment three lamps are arranged at the bottom of the chamber and three lamps are arranged at the top of the chamber. The lamps are in the form of U shaped tubes having an electrical connector at one end thereof and which are pluggable at one end into associated sockets  16  positioned in the housing  10 . The lamps are typically high output, low pressure mercury or amalgam UVC generating lamps such as Light Sources model LTC 24W/2G11/FEP Coated. The length of the lamps is typically about 12 inches. In the illustrated embodiment sufficient UVC radiation is provided to kill 99% of pathogens in 30 seconds or less. Another lamp type is 20 inches long and has a 55 watt capacity 
     The housing  10  can be made of any suitable material and in the illustrated embodiment is aluminum which can be oxidized on the interior walls of the chamber to enhance the reflectance of UVC radiation from the lamps and heighten system efficiency. 
     Preferably each lamp is covered by a protective sleeve to avoid shattering of the lamp quartz glass in the event of breakage. FEP (Teflon) is preferred because it is UV transmissive with little attenuation and can easily withstand the operating temperature of the lamps. A door  18  is hinged to the housing  10  and when open permits access to the chamber  14  for placement and removal of items to be decontaminated. A quartz shelf  20  is provided in the chamber approximately midway of the chamber height. The quartz shelf is UV transmissive and provides support for items to be decontaminated. Such items are typically those found in a hospital or healthcare environment and include hospital bed controls, TV remote controls, cellphones, computer tablets, computer keyboards and the like. A side door  22  is provided on a side of enclosure  10  to provide access for device cords which may be attached to items to be decontaminated, such as for example hospital bed controls. The housing may include a handle  24  for carrying the system. 
     The UVC lamps are driven by a power source having electronic ballasts which start the lamps and regulate the current in each lamp to assure proper and safe operation. Each lamp may be driven by one electronic ballast or a single ballast may drive multiple lamps depending upon the particular lamps and ballasts employed. The electronic ballasts may operate from a standard 110 volt 60 Hz power source or from a 220 volt 50 Hz source or from a dual voltage or other suitable source. A removable power cord may be employed for convenience of system transport. 
     The system is controlled by a microprocessor based microcontroller typically contained on a control board disposed within the housing. The ballasts and power components in the illustrated embodiment are disposed on one side of the housing behind a control panel  26  which in the illustrated embodiment is on the right side of the front of the housing. The control panel  26  is illustrated diagrammatically in  FIG. 2  and includes a display  28  such as a two digit digital display to indicate countdown of remaining time during a decontamination cycle and to indicate system messages such as error conditions. An audio annunciator  30  such as a Sonalert is provided to audibly indicate, such as by a beep, that an operating cycle has ended. The annunciator can also provide distinguishable sounds to denote one or more error conditions. A control switch  32  is provided to activate the system. The control switch can be of the illuminated type which illuminates when actuated to start a decontamination cycle. 
     A block diagram of the system is illustrated in  FIG. 3 . AC input power is provided to a solid state relay  40  and thence to a controller  42  which governs system operation. The solid state relay is coupled to the lamp ballasts  50  which drive the UVC lamps  52 . Over current protection devices such a fuse or circuit breaker may be provided. The controller  42  is coupled to door switch  44 , to displays and controls  46  and to alarm indicators  48 . The display and controls  46  include the displays or indicators of system conditions and controls for system operation, such as those shown in the control panel of  FIG. 2 . The door switches  44  include a switch for door  18  and door  22 . Each of the switches will cause the controller to prevent system operation or shut down operation if a door is opened during an operating cycle. The door can include a locking mechanism which prevents opening of the door during system operation. The side door  22  can include a mechanism to limit the amount of door opening such that a minimal opening is provided that is sufficient to allow passage of an electrical cord to minimize leakage of UV radiation from the chamber  14  into the room in which the system is operating. The side door may have a slot or indented area to accommodate the cord of an item placed in the chamber. 
     The system typically operates for a predetermined period of time as governed by a time period set in the controller. Upon activation of the system by pushing the control switch  32 , the lamps are turned on for the specified period of time and are turned off when the time period ends. The countdown of the operating time is shown in display  28  on the front panel. 
     The controller monitors the current to each of the electronic ballasts to insure that all of the lamps are operating properly. If the current is less than the designated reference value, the controller will turn off the UVC lamps and display a message on front panel display  28 . Typically, the current monitor signal is converted to a digital signal by means of an analog to digital converter for comparison with a stored reference value. In order to determine which UVC lamp is not working properly, the system includes a diagnostic cycle by which the lamps can be turned on when the enclosure door is open. In this manner an operator can see which lamp is not working and have it replaced. A diagnostic cycle can be initiated for example by pressing the start button  32  multiple times within a designated period of time. For example, pressing the start button five times within 5 seconds will cause all of the lamps to be turned on for visual inspection. 
       FIG. 4  illustrates a computer keyboard supported on the quartz shelf disposed in the chamber  14  for decontamination. A device having an electrical cord as illustrated in  FIG. 5  is disposed on the shelf  20  and with the cord  60  threaded through a bottom opening in the side door  22  shown in its tilted open position. 
     It will be appreciated that the invention is not to be limited by the particular embodiment shown and that modifications and alternative implementations are contemplated and are within the intended scope of the invention. For example, the number and type of UVC lamps can vary and the physical configuration of the system may take different forms. Accordingly, the invention is not to be limited by what has been particularly shown and described except as defined by the appended claims.