Abstract:
The present invention provides a system and method for transmitting information between a device within a housing to a second device, preferably a test or monitoring unit, outside of the housing. There are numerous issues associated with transferring information from within a sealed housing to an external device. In some cases, the use of wires inside the housing may be impractical, due to internal conditions, such as fluid flow, pressure or temperature. In one embodiment, the antenna of the external RF reading device is electrically connected to the dome of the housing. In another embodiment, the device within the housing is electrically connected to a housing component. In another embodiment, the gasket is used to pass information from within the housing to an external device.

Description:
This application is a divisional application of U.S. patent application Ser. No. 13/342,413, filed Jan. 3, 2012, which is a divisional application of U.S. patent application Ser. No. 12/879,674, filed Sep. 10, 2010, granted as U.S. Pat. No. 8,114,204, which is a continuation of U.S. patent application Ser. No. 11/581,618, filed Oct. 16, 2006, granted as U.S. Pat. No. 7,811,365, the contents of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The use of wireless communication has become prevalent, especially in the management of assets, particularly those applications associated with inventory management. For example, the use of RFID tags permits the monitoring of the production line and the movement of assets or components through the supply chain. 
     To further illustrate this concept, a manufacturing entity may adhere RFID tags to components as they enter the production facility. These components are then inserted into the production flow, forming sub-assemblies in combination with other components, and finally resulting in a finished product. The use of RFID tags allows the personnel within the manufacturing entity to track the movement of the specific component throughout the manufacturing process. It also allows the entity to be able to identify the specific components that comprise any particular assembly or finished product. 
     In addition, the use of RFID tags has also been advocated within the drug and pharmaceutical industries. In February 2004, the United States Federal and Drug Administration issued a report advocating the use of RFID tags to label and monitor drugs. This is an attempt to provide pedigree and to limit the infiltration of counterfeit prescription drugs into the market and to consumers. 
     Since their introduction, RFID tags have been used in many applications, such as to identify and provide information for process control in filter products. U.S. Pat. No. 5,674,381, issued to Den Dekker in 1997, discloses the use of “electronic labels” in conjunction with filtering apparatus and replaceable filter assemblies. Specifically, the patent discloses a filter having an electronic label that has a read/write memory and an associated filtering apparatus that has readout means responsive to the label. The electronic label is adapted to count and store the actual operating hours of the replaceable filter. The filtering apparatus is adapted to allow use or refusal of the filter, based on this real-time number. The patent also discloses that the electronic label can be used to store identification information about the replaceable filter. 
     A patent application by Baker et al, published in 2005 as U.S. Patent Application Publication No. US2005/0205658, discloses a process equipment tracking system. This system includes the use of RFID tags in conjunction with process equipment. The RFID tag is described as capable of storing “at least one trackable event”. These trackable events are enumerated as cleaning dates, and batch process dates. The publication also discloses an RFID reader that is connectable to a PC or an internet, where a process equipment database exists. This database contains multiple trackable events and can supply information useful in determining “a service life of the process equipment based on the accumulated data”. The application includes the use of this type of system with a variety of process equipment, such as valves, pumps, filters, and ultraviolet lamps. 
     Another patent application, filed by Jornitz et al and published in 2004 as U.S. Patent Application Publication No. 2004/0256328, discloses a device and method for monitoring the integrity of filtering installations. This publication describes the use of filters containing an onboard memory chip and communications device, in conjunction with a filter housing. The filter housing acts as a monitoring and integrity tester. That application also discloses a set of steps to be used to insure the integrity of the filtering elements used in multi-round housings. These steps include querying the memory element to verify the type of filter that is being used, its limit data, and its production release data. This application also describes an internal transponder for relaying information to an external monitoring and test unit. An antenna is arranged adjacent to the transponder on the filter housing. 
     Despite the improvements that have occurred through the use of RFID tags, there are additional areas that have not been satisfactorily addressed. For example, there are issues associated with the ability to transmit data from within a filter housing to an external test or monitoring device. 
     SUMMARY OF THE INVENTION 
     The shortcomings of the prior art are overcome by the present invention, which describes a system and method for transmitting information between the interior of a housing and the exterior of that housing, such as between a device within the housing to a second device, preferably a test or monitoring unit, outside of the housing. There are numerous issues associated with transferring information from within a sealed housing to an external device. In some cases, the use of wires inside the housing may be impractical, due to internal conditions, such as fluid flow, pressure or temperature. In one embodiment, the antenna of the external RF reading device is electrically connected to a portion of the housing, such as the dome of the housing, such that the portion of the housing acts as the antenna. In another embodiment, the device within the housing is electrically connected to a housing component. In another embodiment, a gasket, typically located between the housing dome and the housing base, is used to pass information from within the housing to an external device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a first embodiment of the present invention; and 
         FIG. 2  illustrates a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a representative filtering system in accordance with the present invention, such as that commercially available from Millipore Corporation and sold under the name Filter Cartridge Housing Series 2000. The filter assembly (not shown) is enclosed with a housing dome  40 . The filter assembly has a porous membrane, through which certain materials are able to pass, and the corresponding structure or frame necessary to support this membrane. In certain embodiments, the housing dome is constructed of a non-corrosive, durable material, such as but not limited to stainless steel and other metals or an assembly of conductive and insulative materials. Typically, the housing dome  40  has an opening at the lower end, so that it can be connected to a suitable housing base  70 . The housing base  70  usually contains the various inlets and outlets that allow fluid communication with the filter assembly. For example, fluids can flow into the housing, pass through the membrane of the filter assembly to be filtered and then be drained from the filter assembly through the housing base. Like the housing dome, the base is typically constructed of a non-corrosive material, such as stainless steel. The housing dome  40  is attached to the housing base  70  so as to form a liquid-proof and airtight seal. In some embodiments, the dome  40  is screwed into the housing base  70 . In other embodiments, the housing dome  40  is secured to the housing base  70  through the use of a bottom clamp  50 . The bottom clamp can be constructed of any suitable material, capable of holding these two components together. Typically, a bottom gasket  60  is positioned between the housing dome  40  and the housing base  70  to insure the integrity of the seal between these components. Preferably, the bottom gasket  60  is constructed using a flexible material, such as but not limited to rubber. 
     In one embodiment, the housing dome  40  may also have an opening at the upper end. In this embodiment, a top connector  10  is used to seal this opening. This connector is constructed from a suitable non-corrosive material. As with the bottom opening, the top connector may be screwed to the housing dome, or held in place using a top clamp  30 . The top clamp can be constructed of any suitable material, capable of holding these two components together. Typically, a top gasket  20  is positioned between the housing dome  40  and the top connector  10  to insure the integrity of the seal between these components. Preferably, the top gasket  20  is constructed using a flexible material, such as but not limited to rubber. 
     As described above, within the housing dome are one or more filter assemblies (not shown). These filter assemblies can be simply a porous material, such as pleated paper. Alternatively, the filter assembly may be more complex; for example, comprising a frame, such as of plastic, and a porous material. Within the housing are electronic circuits, such as RFID tags, which can be used to store various types of information about the components. For example, the electronic circuit may include information such as the lot number, production date, test parameters, number of cycles used and other characteristics, properties, operating parameters and/or metrics. For example, these electronic circuits may be attached or embedded in the filter assemblies, and supply data associated with the filter assembly. 
     Outside of the housing dome is a device capable of communicating with these electronic circuits, or tags. In one embodiment, a device  100 , such as an RFID reader, is utilized. This device can be any RFID reader, commercially available from a number of companies. Alternatively, it can be a proprietary reader. The device  100  is in communication with, either directly via a wired connection, or indirectly via a wireless connection, a computer  110 . Alternatively, the device may only be in contact with the computer  110  intermittently. For example, the device may collect a variety of data and store that information internally. At some later time, the device is in communication with (either via a wired or wireless connection) a computer  110 . At this time, the device transfers internally stored data to the computer. The actual interaction between the device  100  and the computer  110  is not critical and a variety of methods are possible and known to those skilled in the art. Consequently, the present invention is not limited to any particular embodiment. 
     Attempting to pass a signal through the housing dome, especially if it is constructed from stainless steel, can be difficult, if not impossible. However, the issue of transmitting information from within the housing dome  40  to the external reader  100  is resolved in a number of ways by the present invention. 
     In a first embodiment, housing dome  40  is electrically isolated from housing base  70 , preferably by utilizing an electrically nonconductive gasket, such as one constructed from rubber. In addition, the means for attaching the dome to the housing base is also non-conductive. For example, the bottom clamp  50  is constructed from non-conductive material, such as thermoplastic or other suitable materials. In this way, the housing base can be grounded, if desired, while the housing dome is kept electrically isolated from it. The dome is preferably constructed of an electrically conductive material, such as copper or stainless steel. 
     Since the housing dome is not grounded or electrically connected to any other components, it can be used to assist in transmitting signals from within the dome to the external device, and vice-versa. In one embodiment, the device, or RF reader,  100  is physically in contact with the housing dome  40 , so that the housing dome serves as the antenna for the device. Thus, the housing dome serves to transmit signals from the device or RF reader to inside the housing, and also serves to receive any signals transmitted from within the housing. In this embodiment, the dome is configured as a ¼ wave antenna installment. In this case, the antenna is configured as a monopole, or whip antenna, wherein only one end of the traditional dipole antenna is used. Those of ordinary skill in the art appreciate that some tuning of the amplitude of the transmitted signals may be required to optimize performance. The embodiments do not limit the shape or materials of construction of the dome to allow someone skilled in the art to tune the effective antennas for optimum performance. 
     In a second embodiment, the housing dome and housing base are isolated from one another, as described above, and both are also isolated from ground. As in the first embodiment, the housing dome is connected to one pole of the device or reader antenna. However, since the housing base is also isolated from ground, it can function as the other pole. Thus, the housing dome and the housing base each function as a pole for a dipole antenna. This is a double electrically floating installment, or a standard dipole antenna. The housing dome and the housing base are each energized by the reader and transmit and receive signals from within the housing. 
     In a third embodiment, the dome is kept electrically isolated from the base as described above. As above, the dome is preferably constructed of an electrically conductive material, such as stainless steel. The dome is then used as an electrical conduit to transmit information from the embedded device directly to the external reader, as though there were a wire between the devices. Preferably, a serial communication protocol is employed between the circuitry within the housing and the external reader. By having both the reader and the circuitry in physical contact with the housing dome, an electrical connection can be made between the internal circuit and the reader. 
     Alternatively, the gasket, which is in the shape of an “O”, that separates the housing dome from the housing base can be used to pass signals from within the housing to the external environment. In one embodiment, a channel or feed through exists in the gasket, in which electrical wires can be placed. This channel, or feedthrough, extends from the portion of the gasket that forms the inner circumference, to the portion of the gasket that forms the outer circumference. Referring to  FIG. 2 , the channel is visible at the outer edge of the gasket. Thus, rather than having the circuitry in physical contact with the housing dome, as described above, a wire, or set of wires, is used to connect the internal circuitry to the external device or reader. The type of communication used and the particular protocol are implement decisions and are all within the scope of the present invention. 
     As a modification to the above embodiments, the electrical connection within the gasket is attached to the housing components. Since the gasket is typically under compression when in use, it is possible to guarantee a connection between the gasket and the housing dome (and housing base). In one embodiment, shown in  FIG. 2 , a small spring or springs is added to the gasket  210  to insure that the electrical connections are in physical contact with the dome. In another embodiment, raised contact pads are located on the gasket and a physical connection is created because of the compression force exerted by the clamps. In the preferred embodiment, the channel does not extend completely through the gasket. Rather, it extends a portion of the way into the gasket, where it is then made to contact with the dome or base. This mechanism provides a simpler method of attaching the antenna of the external device to the dome. For example, the antenna of the external device is connected to the gasket only, with the gasket providing the connection to the dome. In this way, the dome is unfettered by wires or other connection means. This allows the dome to be easily removed from the housing base, and later replaced. In one embodiment, the gasket includes a connector on the outer circumference, suitable for an antenna connection. The antenna of the external device is then connected to this connector, typically by a cable or other suitable means. Within the gasket, the signal is passed, preferably via one or more wires, to a location where it is guaranteed to contact the housing dome, thereby making the connection between the housing dome and the antenna of the external device. Similarly, two separate sets of contact mechanisms, one on the upper side of the gasket facing the housing dome, and one on the lower side of the gasket, facing the housing base, can be utilized. In this way, separate (or the same) signals can be supplied to the housing dome and the housing base, in accordance with an earlier embodiment.