Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-06-08
2001-12-11
Thompson, Gregory (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C165S080400, C165S061000, C165S104330, C062S259200, C174S034000, C174S050510, C361S699000, C361S695000, C361S818000, C219S209000, C219S400000, C219S553000, C055S385200
Reexamination Certificate
active
06330152
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to apparatus for mounting electronic components, and more particularly to such apparatus which is capable of controlling the environment, including temperature, shock and vibration, environmental contaminants, and/or radiation, so as to permit commercial-off-the-shelf (COTS) electronics to be utilized in harsh environments for which such electronics are not designed.
BACKGROUND OF THE INVENTION
In various application, including military, space, commercial and recreational applications, there is a need to operate in harsh and hostile environments where ambient temperature may vary from for example −54° C. to +71° C., ambient pressures may vary from near vacuum condition in for example space applications to 30 psia (i.e. two atmospheres) for underwater applications, the vehicle or other container for the election components may experience significant shock and vibration, the environment may contain contaminants such as salt and various environmental pollutants and the environment may also contain various types of electromagnetic radiation. Such applications include military aircraft, including fixed wing and helicopters, commercial aircraft, space vehicles, military and commercial ships, various military and commercial land vehicles, temporary shelters, docks, offshore platforms, various unmanned remote monitoring stations and the like. Since COTS electronics is normally designed for operation in an office environment between +10° C. and +40°C., it has heretofore been possible to operate electronics in such environments only if the electronics is specially designed for such applications or is either individually packaged or packaged in small functional units designed for such applications. Since the cost of components specially designed for such application is high, few components are available which can operate in such environments and such components are typically far behind the current state of the art. Environmentally packaging components, or small groups of components, can also be expensive and results in a final product which is generally bulky, heavy and expensive. Such packaging may also have significant power requirements. Costs are further increased by the fact that it is frequently necessary to custom design the packaging or box for each unit being packaged.
A need therefore exists for a packaging technique which permits COTS electronics, including the most up-to-date, high performance COTS electronics, to be used in the various hostile environments indicated above without requiring customization of the electronic component itself or custom packaging for the components or units in which it is used, and which thus permits such components to be used in hostile environments at lower cost, with less added size and weight and with greater flexibility than is possible with existing environmental packaging techniques. Further reductions in cost, size, and weight may also be achieved by taking advantage of relaxed environmental specifications for some applications. For example, where the only environment for the application is a low temperature environment, operation in the range of −54° C. to +40° C. may be adequate, rather than requiring operation of up to +71° C.
SUMMARY OF THE INVENTION
In accordance with the above, this invention provides apparatus for permitting commercial-off-the-shelf (COTS) electronics to be utilized in harsh environments for which the COTS electronics are not designed, which apparatus includes an environmentally sealed enclosure; mounts in said enclosure for holding the COTS electronics; a temperature sensor within the enclosure; an environmental control unit (ECU) in said enclosure, said ECU including a cooler which, when operated. cools fluid passing thereover, a heater which, when operated, heats fluid passing thereover, and controls operative at least in part in response to said temperature sensor for selectively operating said cooler and said heater; and a mechanism for circulating fluid in said enclosure through said mounts and said ECU, the temperature of the fluid being appropriately controlled as it circulates through the ECU. The cooler is preferably a compressor, the enclosure including a channel sealed from the remainder of the enclosure through which ambient external fluid (generally air, or water, or two phase coolant) is circulated to cool the compressor. The walls of such channel may be formed of a corrosion-resistant material, as may the walls of the entire enclosure. The apparatus may include a mechanism which circulates air through the channel at least when the compressor is being operated, which mechanism may, but need not, be turned off when the heater is operated or when neither the heater nor the compressor are being operated. The channel may also be closed when the heater is operated to reduce heat loss.
The walls of the enclosure are preferably thermally insulated; the ECU and/or the mounts may also be thermally insulated. The apparatus may also include a mechanism for inhibiting vibration and/or shock for the COTS electronics. For example, an adapter plate may be provided for mounting the enclosure and the vibration inhibiting mechanism may include shock mounts between the adapter plate and the enclosure. Alternatively, the vibration inhibiting mechanism may include shock mounts between the mounts and the enclosure either in addition to or instead of shock mounts external to the enclosure. The enclosure must maintain structural integrity during shock impulses encountered during for example a crash for airborne applications to ensure the safety of the crew.
The enclosure may also have a removable panel through which access to the enclosure is provided, said panel being attached and sealed to the remainder of the enclosure when the apparatus is in use. This seal is preferably both an environmental and an electromagnetic seal.
The fluid circulating in the enclosure is normally a gas, for example air. A mechanism may be provided for removing moisture from the enclosure, which mechanism, for many embodiments, is operated at start-up or at other times when the system is off-line. Alternatively, a dry gas such as dry nitrogen, may be utilized as the recirculating gas to substantially eliminate moisture from the enclosure.
The apparatus may also be sealed to operated in an explosive environment, this generally involving hermetically sealing each element, such as switches, in the enclosure which might potentially generate a spark. The temperature sensor in the enclosure may include at least one on/off switch and preferably includes a first on/off switch for controlling the cooler and a second on/off switch for controlling the heater. The on/off switches may for example be bimetallic switches. Further, where the cooler utilizes a fluid refrigerant flowing through piping, such piping may also be hermetically sealed. particularly at its joints, to prevent leakage of the refrigerant into the enclosure.
The sealed enclosure may also be shielded and/or sealed to inhibit electromagnetic radiation passing therethrough in either direction, and may also include an RFI filter on the ECU and/or electronics. The ECU controls may also be operative for reducing power usage and/or acoustic noise. For preferred embodiments, the mounts are racks which are adapted for holding a plurality of COTS circuit boards.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings.
REFERENCES:
patent: 5160357 (1992-11-01), Faber
patent: 5202815 (1993-04-01), Le Boennec et al.
patent: 5801632 (1998-09-01), Opal
patent: 5808866 (1998-09-01), Porter
patent: 5894407 (1999-04-01), Aakalu et al.
patent: 6127663 (2000-10-01), Jones
Feduke Ronald J.
Jennings Robert L.
Nielsen Jan M.
Vos David L.
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