Abstract:
A method of actively transporting atmosphere, including gases and other fluids, to and from an inner compartment of a sealed system. The purged atmosphere is replaced with another atmosphere having target characteristics. A vacuum purge system pulls atmosphere from the sealed system, while a pressure-based system pushes atmosphere into the sealed system. Humidity corrosion tests are accelerated over prior methods because purged atmosphere is actively transported out of the sealed system and characteristic atmosphere is actively transported into the sealed system.

Description:
FILED OF THE INVENTION  
         [0001]    This application relates generally to environmentally testing a sealed system. More particularly, the application relates to actively transporting atmosphere having target criteria into an internal compartment of the sealed system to rapidly expose the internal compartment to the target atmosphere.  
         BACKGROUND OF THE INVENTION  
         [0002]    Many electronic devices, such as disc drives, undergo performance tests. One type of performance test is an environmental test, wherein a device, including the device&#39;s internal components, is tested under predetermined environmental conditions. Environmental testing of these devices can occur at any point in the development process of the electronic device. Frequently testing occurs after a design stage and before a large-scale manufacturing stage to test the design of the device. Environmental testing may also occur as an ongoing quality assurance effort after large-scale manufacture begins. Regardless of where in the development process environmental testing occurs, makers of these devices are typically strongly motivated to reduce “time-to-market”; i.e., the time required from initial design to actual sales in the market. Additionally, in order for environmental tests to be of most value, the testing should be controllable and deliver consistent results.  
           [0003]    Many electronic devices are sealed or substantially sealed so that internal components of the electronic device are protected from potentially destructive elements. The sealed nature of many electronic devices, and disc drives in particular, often makes environmental testing difficult, uncontrollable, and time-consuming. Prior approaches to environmental testing of sealed devices incur a substantial time requirement that significantly increases the time-to-market beyond the time-to-market without such testing. The substantial time requirement is largely due to the sealed nature of many electronic devices.  
           [0004]    For example, in the disc drive industry, in order to test corrosive effects of humidity on internal components of a disc drive, the disc drive is placed in an environmental chamber and left in the chamber until the atmosphere in the internal compartment of the disc drive meets predetermined criteria. The environmental chamber modifies the atmosphere surrounding the disc drive in the chamber to meet a predetermined relative humidity. The disc drive cannot be tested until the internal compartment of the disc drive reaches the test relative humidity, to ensure that the inner components have been exposed to the humidity. Because disc drives are substantially sealed to protect the internal components, for some models of disc drives it takes several days to weeks for the inner compartment of the disc drive to reach the predetermined humidity level required for testing.  
           [0005]    Another problem is related to variability in designed-in diffusion paths. For example, some disc drives have a designed-in breather hole to allow equilibration of pressure between their interior and exterior environments. These breathers may include diffusion-limiting features. Manufacturing processes of the breather holes and their associated features create variability in their dimensions, creating variability in diffusion rates. Thus, using passive approaches to reach equilibration in disc drives having breather holes and diffusion features with wide variability lead to environmental test results with wide variability. The wide variability of results obtained using designed-in diffusion paths can make results interpretation, comparison, and decision-making difficult.  
           [0006]    A related problem is inconsistency of environmental test results. Because diffusion paths and their associated diffusion rates are largely random and variable as discussed above, test results are often inconsistent from device to device due to dissimilarity in exposure experienced by internal components. For example, one disc drive may have a higher diffusion rate, and thus have internal components more exposed to humidity than another disc drive that has a lower diffusion rate and thus less internal exposure to humidity. Differences in test results in the example most likely indicate a difference in diffusion rate, and not the ability of internal components to operate after exposure to humidity. The range of diffusion rates across different device designs or models is typically much greater than within a particular device design. Thus, inconsistencies in environmental test results are particularly pronounced when devices are from a different design or model.  
           [0007]    Accordingly there is a need for a system and method of controlling and/or accelerating environmental testing of substantially sealed devices.  
         SUMMARY OF THE INVENTION  
         [0008]    Embodiments of the present invention accelerate environmental testing of substantially sealed devices by creating a direct connection between a target environment and the inner compartment of the device. A port in a casing of the device allows for direct communication of a target environment to the inner compartment. Embodiments include a pressurization mechanism for pulling or pushing target atmosphere into the inner compartment, thereby accelerating equilibration of the inner compartment with the target atmosphere. In a particular embodiment, a substantially sealed device is placed in an environmental chamber, a pump is attached to a port in the casing of the device, and the pump is activated to pull a target atmosphere from the environmental chamber into the inner compartment of the device through a flow path, such as a breather hole.  
           [0009]    An embodiment of the present invention may be viewed as a method of environmentally testing a substantially sealed device by actively transporting atmosphere from a test environment into an internal compartment of the substantially sealed device. Actively transporting atmosphere may involve connecting a proximate end of an atmosphere transport connector to a port in a housing of the device and activating a pressurization mechanism to actively transport atmosphere out of the internal compartment via the atmosphere transport connector, and to actively transport the atmosphere from the test environment into the internal compartment of the device via a flow path in the housing.  
           [0010]    The method may further include placing the device in an environmental chamber having a target atmosphere meeting target criteria, and establishing the test environment in the environmental chamber. The method may further include connecting a pump to a distal end of the atmosphere transport connector, and activating the pump to pull atmosphere from the internal compartment of the substantially sealed device.  
           [0011]    Another embodiment may be viewed as an environmental test system for performing environmental tests on a device having a housing that forms a substantially sealed internal compartment, wherein the housing has a flow path allowing atmosphere to flow there through. The environmental test system includes a port module attached to an opening in the housing. In a particular embodiment, the port module is attached to an atmosphere transport connector to transport atmosphere to or from the internal compartment, and/or a pressurization mechanism in fluid communication with the internal compartment of the device and the atmosphere transport connector.  
           [0012]    One embodiment of the environmental test system includes a pump attached to a distal end of the atmosphere transport connector, whereby the pump can pull atmosphere out of the internal compartment. In another embodiment, spinning discs in a disc drive serve as the pressurization mechanism. In yet another embodiment, a controlled flow path module is included to create a desired flow rate in the device for simulating diffusion through the housing of the device.  
           [0013]    These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a plan view of a disc drive having a substantially sealed casing forming an inner compartment, which may be environmentally tested using an embodiment of the present invention.  
         [0015]    [0015]FIG. 2 is a perspective cutaway view of an environmental chamber having a target environment and a disc drive immersed therein in accordance with an embodiment of the present invention.  
         [0016]    [0016]FIG. 3 is a side-on sectional view of a disc drive in an environmental chamber in accordance with an embodiment of the present invention.  
         [0017]    [0017]FIG. 4 is a side-on sectional view of a disc drive in an environmental chamber having a controlled diffusion mechanism, a humidity sensor, and a valve in accordance with an embodiment of the present invention.  
         [0018]    [0018]FIG. 5 is a perspective view of a manifold that may be used to connect multiple devices to a pump for environmental testing in accordance with an embodiment of the present invention.  
         [0019]    [0019]FIG. 6 is a graph illustrating a response to application of a target environment in accordance with an embodiment of the present invention.  
         [0020]    [0020]FIG. 7 is an operation flow diagram illustrating exemplary operations performed in accordance with an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0021]    Exemplary embodiments of the present invention are described herein with reference to a series of figures. An embodiment of the present invention may be viewed as a method or system for performing an environmental test upon a substantially sealed device having a casing, housing components in an internal compartment. More particularly, an embodiment includes a method or system for actively transporting atmosphere into the internal compartment of the device. More particularly still, an embodiment includes forming a port in the casing, coupling a pressurization mechanism to the port, and activating the pressurization mechanism to actively transport atmosphere meeting target environmental criteria into or out of the internal compartment of the device. The method may further include closing the port. As a result of active transport of atmosphere, atmosphere in the internal compartment equilibrates quickly with respect to atmosphere outside the casing of the device.  
         [0022]    Embodiments of the testing system and method are described herein in an exemplary context of environmentally testing a disc drive. A disc drive is one particular type of substantially sealed device having a casing that houses components in an internal compartment. The components in the internal compartment may be electronic or otherwise, and typically exhibit a response to elements that enter the internal compartment. By way of example, and not limitation, humidity in the atmosphere in the internal compartment can cause a corrosive effect upon the components, and may cause the components to behave differently than a standard behavior. It is to be understood that other types of substantially sealed devices that have internal compartments may be tested using embodiments of the present invention, and that a disc drive is merely one example of one such device that may undergo testing. It is also to be understood that environmental testing using systems and methods described herein, may involve use of test atmosphere having any relevant testing parameters, and humidity is merely one example of one such testing parameter.  
         [0023]    A disc drive  100  constructed in accordance with a preferred embodiment of the present invention is shown in FIG. 1. The disc drive  100  includes a base  102  to which various components of the disc drive  100  are mounted. A top cover  104 , shown partially cut away, cooperates with the base  102  to form an internal, substantially sealed environment or compartment for the disc drive in a conventional manner. The top cover  104 , together with the base  102 , forms a casing or housing that contains the components in the internal compartment. The components include a spindle motor  106 , which rotates one or more discs  108  at a constant high speed. Information is written to and read from tracks on the discs  108  through the use of an actuator assembly  110 , which rotates during a seek operation about a bearing shaft assembly  112  positioned adjacent the discs  108 . The actuator assembly  110  includes a plurality of actuator arms  114  which extend towards the discs  108 , with one or more flexures  116  extending from each of the actuator arms  114 . Mounted at the distal end of each of the flexures  116  is a head  118  which includes an air bearing slider enabling the head  118  to fly in close proximity above the corresponding surface of the associated disc  108 .  
         [0024]    During a seek operation, the track position of the heads  118  is controlled through the use of a voice coil motor (VCM)  124 , which typically includes a coil  126  attached to the actuator assembly  110 , as well as one or more permanent magnets  128  which establish a magnetic field in which the coil  126  is immersed. The controlled application of current to the coil  126  causes magnetic interaction between the permanent magnets  128  and the coil  126  so that the coil  126  moves in accordance with the well-known Lorentz relationship. As the coil  126  moves, the actuator assembly  110  pivots about the bearing shaft assembly  112 , and the heads  118  are caused to move across the surfaces of the discs  108 .  
         [0025]    The spindle motor  106  is typically de-energized when the disc drive  100  is not in use for extended periods of time. The heads  118  are moved over park zones  120  near the inner diameter of the discs  108  when the drive motor is de-energized. The heads  118  are secured over the park zones  120  through the use of an actuator latch arrangement, which prevents inadvertent rotation of the actuator assembly  110  when the heads are parked.  
         [0026]    A flex assembly  130  provides the requisite electrical connection paths for the actuator assembly  110  while allowing pivotal movement of the actuator assembly  110  during operation. The flex assembly includes a printed circuit board  132  to which head wires (not shown) are connected; the head wires being routed along the actuator arms  114  and the flexures  116  to the heads  118 . The printed circuit board  132  typically includes circuitry for controlling the write currents applied to the heads  118  during a write operation and a preamplifier for amplifying read signals generated by the heads  118  during a read operation. The flex assembly terminates at a flex bracket  134  for communication through the base  102  to a disc drive printed circuit board (not shown) mounted to the bottom side of the disc drive  100 .  
         [0027]    A perspective view of an environmental test system  200  is illustrated in FIG. 2. The environmental test system includes an environmental chamber  202 . A top cover  201  of the chamber  202  is partially cut away to expose an internal cavity  203 , wherein a substantially sealed device, such as the disc drive  100 , is positioned. The cavity  203  of the environmental chamber  202  contains an atmosphere that substantially surrounds the disc drive  100 . The atmosphere is composed of any number of gases. The atmospheric gases generally refer to fluids in the gaseous state having neither independent shape nor volume and being able to expand indefinitely. A fluid refers generally to a continuous amorphous substance that tends to flow and to conform to the outline of its container, such as the environmental chamber  202 . By way of example, and not limitation, a gas includes an aerosol composition, which includes particles in a non-gaseous phase that are suspended in the gas.  
         [0028]    The atmosphere in the cavity  203  of the environmental chamber  202  is characterized by certain parameters, such as, but not limited to, a relative humidity, a temperature, aerosol composition, concentration of gases other than air, and density. The environmental chamber  202  is operable to modify one or more parameters of the atmosphere to reach predetermined target values. In one embodiment, the environmental chamber  202  is operable to adjust the temperature of the atmosphere in the cavity  203  to reach a predetermined target temperature. In another embodiment, the environmental chamber  202  is operable to adjust the relative humidity of the atmosphere in the cavity  203  to reach a predetermined target relative humidity. In yet another embodiment, the environmental chamber  202  is operable to maintain a target relative pressure within the cavity  203 . The target values for the atmosphere are typically chosen in accordance with environmental tests, which the disc drive  100  is to undergo.  
         [0029]    The environmental tests may be designed to test component behavior under anticipated operational conditions of the disc drive  100 . Alternatively, the environmental tests may test the disc drive  100  under stressed (non-operational) conditions. For example, an environmental test under operational conditions may include testing the disc drive  100  in atmosphere having a target relative humidity of 20%. An example of a stress test is one that tests the disc drive  100  in 80% relative humidity. The environmental chamber  202  is able to adjust the characteristics of the atmosphere that surrounds the disc drive  100  to meet target characteristics, but because of the substantially sealed nature of the disc drive  100 , the environmental chamber  202  may not be able to directly change the target characteristics of the atmosphere in the internal compartment of the disc drive  100 .  
         [0030]    In the particular embodiment illustrated in FIG. 2, a proximate end of a connector  204  is coupled to a port (not shown) in the casing of the disc drive  100 . The connector  204  is connected to a valve  206 , which can be opened and closed to start or stop air flow between the connector  204  and the disc drive  100 , respectively. The valve  206  is attached to a port module  208 , which includes a sensor connector  210  and a diffusion controller  212 . The port module  208  is affixed to the port (not shown) in the disc drive  100  casing to thereby hold the port  208 , the valve  206 , and the connector  204  in position to facilitate active transportation of atmosphere from the cavity  203  into the inner compartment of the disc drive  100 .  
         [0031]    In one embodiment, a distal end of the connector  204  extrudes outside a wall of the chamber  202  and connects to a pressurization mechanism, such as a pump. Via the connector  204 , fluid communication is established between the internal compartment of the disc drive  100  and the pump. When the pump is turned on, atmosphere is pulled out of the internal compartment of the disc drive  100 . In response, atmosphere in the cavity  203  is pulled into the internal compartment of the disc drive  100 . Thus, the internal compartment and components housed therein are rapidly exposed to the target environment created in the chamber  202 .  
         [0032]    In one embodiment, the sensor connector  210  is coupled to a humidity detector in the port module  208 . The humidity detector (not shown) detects humidity in the atmosphere of the internal compartment of the disc drive  100  and/or atmosphere flowing between the internal compartment and the connector  204 . A signal path  214  carries signals from the humidity detector. The signals from the humidity detector may be used for any number of purposes, including but not limited to, closing the valve  206 , turning off a pump, and/or any relevant analysis. The signal paths  214  include any communication mechanism, such as electrical wiring, or a wireless communication path.  
         [0033]    The connector  204  and the signal paths  214  extrude beyond walls of the environmental chamber  202  in a particular embodiment of the environmental testing system  200 . For example, the connector  204  in a preferred embodiment is connected to a pressurization mechanism, such as a pump, for pulling atmosphere out of the internal compartment of the disc drive  100 . While the pump pulls atmosphere out of the internal compartment of the disc drive  100 , a pressure is created that pulls atmosphere from the cavity  203  of the environmental chamber  202  into the internal compartment of the disc drive  100 . Points at which the connector  204  and the signal paths  214  leave the surface of the environmental chamber  202 , preferably include a sealing mechanism, such as a gasket, and/or o-ring, to prevent leaks in the system  200 . In one embodiment, the valve  206  is a solenoid valve powered by an electrical signal. In an alternative embodiment, the valve  206  is powered in a pneumatic fashion by atmosphere being pulled through the valve.  
         [0034]    [0034]FIG. 3 is a side-on sectional view  300  of a disc drive  100  in an environmental chamber  302  in accordance with an embodiment of the present invention. The disc drive  100  is positioned in a cavity  304  of the chamber  302 . The cavity  304  contains atmosphere meeting target criteria, such as, but not limited to, target humidity, temperature or gaseous contaminant. The chamber  302  includes a top wall  306 , a first side wall  308 , a second side wall  310 , and a bottom wall  312 . Together the walls  306 ,  308 ,  310 , and  312 , create the cavity  304 .  
         [0035]    In the particular embodiment shown in FIG. 3, the disc drive  100  rests on risers, such as shelves  314 , such that the disc drive  100  is substantially surrounded by atmosphere in the cavity  304 , including the bottom surface of the disc drive  100 . The risers raise the disc drive  100  off the bottom wall  312  of the environmental chamber  302 . Examples of other types of risers are raised platforms or shelves with aerated slots that allow the cavity atmosphere to contact the base  102  of the disc drive  100 . The disc drive  100  includes a flow path, such as a breather hole  316 . The breather hole  316  may be used for pressure equilibration and out-gassing undesirable gasses that often form during disc drive operation. In many disc drive designs, the breather hole  316  includes a filter and/or an absorbent material for filtering out undesirable contaminants that may harm the components in the disc drive  100 . In the disc drive industry the breather hole  316  may also include a diffusion-limiting feature, such as a labyrinth. Embodiments of the present invention overcome the filtering or absorbent nature of the breather hole for testing purposes. Via the breather hole  316 , atmosphere can be pulled into the inner compartment  320  to facilitate analysis of the response exhibited by components in the disc drive  100 .  
         [0036]    In a particular embodiment, a connector  318  connects the disc drive  100  to a pressurization mechanism, such as a pump  324 , in order to pull atmosphere from the cavity  304  into the inner compartment  320  of the disc drive  100  via the breather hole  316 . The connector  318  is connected to a port  322  on the top cover  104  of the disc drive  100 . The connector  318  may be attached by any means as may be known in the art, including, but not limited to, a threaded coupling, or a glue mount. The connection between the port  322  and the connector  318  is preferably sealed to prevent leakage. A pump  324  connected to the connector  318  creates a pressure or suction that pulls atmosphere out of the inner compartment  320  of the disc drive  100 , which in turn pulls atmosphere from the cavity  304  into the inner compartment  320  of the disc drive  100 . Consequently, by using the pump  324  or other pressurization mechanism, atmosphere is actively transported from the chamber cavity  304  into the internal compartment  320  of the disc drive  100 .  
         [0037]    By actively transporting atmosphere from the cavity  304  into the internal compartment  320  of the disc drive  100 , the atmosphere in the internal compartment  320  equilibrates quickly with the atmosphere in the cavity  304 . By rapidly equilibrating the atmosphere in the internal compartment  320  with the atmosphere in the cavity  304 , environmental testing can be greatly expedited over prior approaches that do not use active atmosphere transport. In addition, and in contrast to prior approaches, the process of filling the internal compartment  320  with target atmosphere is controllable. For example, the pump  324  connected to the disc drive  100  may be turned on or off at controlled times, or the pressure applied by the pump  324  may be controlled.  
         [0038]    In another embodiment, atmospheric pressure in the cavity  304  of the environmental chamber  302  is elevated with respect to the atmospheric pressure in the internal compartment  320  of the disc drive  100  to facilitate more rapid equilibration. In this embodiment, atmospheric flow generated by the pump  324  is increased due to the pressure differential. The pressure differential between the atmosphere in the cavity  304  and the compartment  320  essentially pushes the atmosphere from the cavity  304  into the internal compartment  320  via the breather hole  316 . Examples of chambers that may be used in this elevated pressure embodiment are an elevated pressure chamber and an autoclave, among others.  
         [0039]    [0039]FIG. 4 is a side-on sectional view  400  of a disc drive  100  in an environmental chamber  402  in accordance with another embodiment of the present invention. In this particular embodiment, the top surface  104  of the disc drive  100  includes a port  406  attached to a port module  408  that couples the internal compartment  410  of the disc drive  100  to an external connector  412 . Via the port  406 , the port module  408 , and the external connector  412 , atmosphere can flow from the internal compartment  410  out of the disc drive  100 .  
         [0040]    In a particular embodiment, the port module  408  has a controlled diffusion mechanism  414 , and a sensor  416  attached thereto. The controlled diffusion mechanism  414  is adjustable during testing to simulate an airflow path in the housing of the disc drive  100 . The sensor  416  is immersed in atmosphere from the internal compartment  410  and detects a predetermined atmospheric condition relevant to environmental testing. One embodiment of the sensor  416  is a humidity sensor that detects the level of relative humidity in the atmosphere of the internal compartment  410  of the disc drive  100 . Sensor signals from the sensor  416  are carried by signal paths  418 , and may be used during testing for a variety of purposes, examples of which are discussed below in detail. The particular placement of the port module  408 , controlled diffusion mechanism  414 , and the sensor  416  may be changed for any particular implementation without straying from the scope of the present invention.  
         [0041]    In another particular embodiment, the port module  408  has a valve  420  that couples the external connector  412  to the port module  408 . The valve  420  may be opened and closed to control airflow to and from the internal compartment  410  of the disc drive  100 . The valve  420  may be opened and closed electronically, manually, or pneumatically, or by any other mechanism as may be known in the art. One embodiment of the valve  420  is a solenoid valve. It is to be understood that FIG. 4 illustrates the controlled diffusion mechanism  414 , the sensor  416 , and the valve  420  in a particular embodiment of an environmental test system. Other embodiments may not have the controlled diffusion mechanism  414 , the sensor  416 , or the valve  420  or may have one or more of these features in any combination.  
         [0042]    As illustrated, the disc drive  100  rests on a riser, such as a platform  422 , such that atmosphere in the environmental chamber  402  substantially surrounds the bottom surface  102  of the disc drive  100 . In the particular embodiment shown in FIG. 4, the platform  422  has stand-offs  426  to create a void  428  between the bottom surface  102  and the platform  422 . Other types of risers as are known in the art may be used in any particular implementation.  
         [0043]    The disc drive  100  includes a flow path in the casing of the disc drive, such as a breather hole  430  in the bottom surface  102 . As discussed above, the breather hole  430  may contain a filter or absorbent material. The breather hole  430  allows atmosphere to flow in and out of the internal compartment  410  of the disc drive  100 . In a particular embodiment, the atmosphere in the environmental chamber  402  is pulled through the breather hole  430  and into the internal compartment  410  of the disc drive  100 . For example, atmosphere in the cavity of the chamber  402  can be pulled through the breather hole  430  into the internal compartment  410  by opening the valve  420  and spinning one or more discs  108  in the disc drive  100 . When the discs  108  spin, the target atmosphere is pulled into the internal compartment  410  via the breather hole  430 , and atmosphere is actively transported out of the internal compartment  410  via the atmosphere transport connector  412 .  
         [0044]    In an alternative embodiment, a pressurization mechanism, such as a pump (not shown), is connected to the atmosphere transport connector  412 . In this embodiment, the pump pulls atmosphere from the internal compartment  410  when the valve  420  is opened. In response to pulling atmosphere from the internal compartment  410 , atmosphere is pulled from the cavity of the environmental chamber  402  through the breather hole  430  and into the internal compartment  410 .  
         [0045]    When atmosphere flows past the sensor  416 , the sensor  416  detects an atmospheric condition, such as relative humidity in the atmosphere. In one embodiment, in response to detection of the relative humidity, a signal is sent via the signal paths  418  to a test module (not shown) that responds to the signal from the sensor  416 . In one embodiment, the test module may record the level of relative humidity sensed by the sensor  416 . In an alternative embodiment, the test module responsively initiates an action in the test process, such as, closing the valve  420 , or deactivating the pressurization mechanism (e.g., spinning down the discs  108  or turning off a pump) when the detected relative humidity reaches a threshold level.  
         [0046]    For example, when the relative humidity detected by the sensor  416  reaches a target relative humidity, the discs  108  may be spun down (deactivated) to stop active transport of atmosphere into the internal compartment  410  of the disc drive  100 . As another example, in response to detecting a target relative humidity by the sensor  416 , a pump connected to the atmosphere transport connector  412  may be deactivated to stop active transport of atmosphere into the internal compartment  410  of the disc drive  100 .  
         [0047]    In a particular embodiment, distribution connectors  432  are provided on the transport connector  412 . The distribution connectors  432  may be connected to multiple disc drives to allow for simultaneous equilibration of multiple disc drives for environmental testing. In this embodiment, a pressurization mechanism can be connected to a distal end of the connector  412  to facilitate active transport of target atmosphere into internal compartments of disc drives coupled to proximate ends of the distribution connectors  432 . Another embodiment may use distribution connectors  432  in combination with a manifold.  
         [0048]    [0048]FIG. 5 illustrates a manifold  500  that may be used to connect multiple sealed devices to one or more pumps to facilitate active transport of atmosphere into the devices in accordance with an embodiment of the present invention. In a particular embodiment of the manifold  500 , atmosphere pressure created by the pump is distributed among 16 connectors  502  and may allow for active transport of atmosphere into the internal compartments of 16 corresponding sealed devices simultaneously. As illustrated in FIG. 5, the manifold  500  includes 16 switches  504 , each switch  504  being associated with one of the atmosphere transport connectors  502 . A controller  506  controls atmosphere flow through the atmosphere transport connectors  504 . Although the manifold  500  is shown as having 16 connectors corresponding to 16 devices under test, it is to be understood that any number of connectors and devices may be connected through a manifold. The number of connectors in the manifold depends on the particular implementation.  
         [0049]    [0049]FIG. 6 illustrates a graph  600  having response curves related to responses to changes in relative humidity during environmental testing. The graph  600  includes a range of percent relative humidity values  602  on the vertical axis and a range of time values  604  on the horizontal axis. Thus, the graph  600  illustrates change in percent relative humidity over time.  
         [0050]    The graph  600  illustrates results from environmental testing for two environmental tests. In both tests, a disc drive was placed in an environmental chamber, and the environmental chamber was turned on to create a target relative humidity within the environmental chamber. The chamber response curve  606  illustrates the change in percent relative humidity within the environmental chamber over time in an apparatus constructed and operated in accordance with an embodiment of the present invention. When the environmental chamber was switched on, and within about the first hour, the percent relative humidity within the chamber changes from around 25% relative humidity to around 80% relative humidity, which, in this embodiment, is the target relative humidity. The chamber response curve  606  represents the environmental test conditions within the chamber, with which the internal compartment of the a disc drive is to equilibrate.  
         [0051]    In one environmental test, a disc drive was placed in the chamber and atmosphere was not actively transported into the internal compartment of the disc drive. During this test, the percent humidity within the internal compartment of the disc drive was monitored as it naturally changed in response to the relative humidity in the chamber. The result of this test is seen in a natural response curve  608 . The natural response curve  608  illustrates that at time 0, atmosphere in the internal compartment of the disc drive has a relative humidity of around 12% relative humidity. By diffusion through diffusion paths in the casing of the disc drive, such as the diffusion-limiting breather hole, the percent relative humidity of atmosphere in the internal compartment of the disc drive slowly increases to around 68% relative humidity after around 65 hours. As can be seen in the natural response curve  608 , using the natural, or passive, approach toward equilibration, the internal compartment of the disc drive does not reach the target percent relative humidity (i.e., 80%), within 65 hours of waiting.  
         [0052]    In a second test, a disc drive was placed in the chamber and atmosphere was actively transported into the internal compartment of the disc drive using methods and systems in accordance with an embodiment of the present invention. As a result of this test, a forced response curve  610  was generated. As illustrated, the forced response curve  610  jumps from around 25% relative humidity to around 80% relative humidity (i.e., the target relative humidity), within around the first hour of testing. After around the first hour of testing, the forced response curve  610  dips slightly to around 75% relative humidity but subsequently increases back to the target relative humidity; i.e., 80% relative humidity.  
         [0053]    After reaching 80% relative humidity, the atmosphere in the internal compartment of the disc drive substantially maintains the percent relative humidity as can be seen by the forced response curve  610 . Thus, as can be seen by the graph  600 , by using active atmosphere transport methods and systems as described herein, equilibration of atmosphere in the internal compartment of a substantially device and atmosphere outside the device occurs substantially more quickly than when these methods and systems are not used.  
         [0054]    An operation flow  700  is illustrated in FIG. 7 having exemplary operations that may be used in accordance with one embodiment of the present invention. In general, the operations illustrated in operation flow  700  may be used to expose components in an internal compartment of a device under test to target environmental parameters using active atmosphere transport methods. In this particular embodiment, a pump is used to actively transport atmosphere into the internal compartment of a device that is under test; however, it is to be understood that other pressurization mechanisms, other than a pump, may be used to perform the operations described herein. In addition, the operation flow  700  is easily adapted by one skilled in the art to facilitate environmental testing multiple substantially sealed devices simultaneously.  
         [0055]    After a start operation  702 , a fitting is attached to the device under test in an attach operation  704 . In one embodiment, the fitting is a threaded fitting that attaches an atmosphere transport connector to a port in a housing of the device under test. After the fitting is attached, the device under test is placed in an environmental chamber in a place operation  706 . In an attach operation  708 , a pump is attached to a fitting on a distal end of the atmosphere transport connector. After the pump is attached, an establish operation  710  establishes a target environment in the environmental chamber. The target environment may be established in a conventional environmental chamber that has adjustable settings related to target environmental parameters that may be set by an operator. In one embodiment, the target environment includes a target percent relative humidity. In other embodiments, target atmosphere criteria, in addition to or other than a target percent relative humidity, is established in the established operation  710 .  
         [0056]    An activate operation  712  activates the pump to begin pumping atmosphere into or out of the internal compartment of the device that is under test. In one embodiment of the activate operation  712 , activating the pump includes opening a valve disposed between the pump and the port in the device under test. After the pump is activated in the activate operation  712 , a pump operation  714  actively transports atmosphere from the environmental chamber into the internal compartment of the sealed device until the atmosphere in the internal compartment meets the target criteria for the test. The pump operation  712  may involve actively transporting atmosphere by using pressure or suction. Results of tests of disc drives using active atmosphere transport methods described herein show that the pump operation  714  can reach equilibration in around two hours for disc drives. The range of time for equilibration in the pump operation  714  may vary depending on the particular implementation. Tests indicate that by using active atmosphere transport as described herein, the time for equilibration in the pump operation  714  is substantially reduced over prior approaches wherein passive transport methods are used.  
         [0057]    After equilibration is established, a deactivate operation  716  deactivates the pump. The deactivate operation  716  may involve turning off the pump and/or closing a valve disposed between the pump and the port on the device under test. In a soak operation  718 , the device under test soaks in the target environment. In one embodiment, the device under test soaks in atmosphere that has a target humidity of 80% relative humidity in order to test a corrosive effect of humidity on components within the device under test. The soak operation  718  exposes internal components of the test device to the target environment for a predetermined amount of time. The amount of time that the device is soaked (in the soak operation  718 ) in the target environment depends on the type of test and the particular implementation.  
         [0058]    After the soak operation  718 , a ramp down operation  720  ramps the internal compartment of the device under test down to a non-target environment, such as the ambient atmosphere or the environment in the internal compartment prior to equilibration. In one embodiment of the ramp down operation  720 , the device under test is taken out of the environmental chamber, thus removing the device under test from the target environment. In this embodiment, the pump is then turned on to pump non-target environment atmosphere into the internal compartment of the device under test. The ramp down operation  720  is optional, and may greatly reduce the overall time for environmental testing.  
         [0059]    After the ramp down operation  720 , a run operation  722  runs tests on the device under test. The run operation  722  involves executing any relevant tests on the device under test and its internal components to determine how the device and its components respond to the effects of the target environment. Any tests may be run in the run operation  722 , and the particular tests that are run are not relevant to embodiments of the present invention. After the tests are run in the run operation  722 , an end operation  724  ends the operation flow  700 .  
         [0060]    In summary, an embodiment of the present invention may be viewed as a method of environmentally testing a substantially sealed device (such as  100 ) by actively transporting (such as  712 ,  714 ) atmosphere from a test environment (such as  304 ) into an internal compartment (such as  320 ) of the substantially sealed device (such as  100 ). Actively transporting atmosphere may involve connecting (such as  704 ,  708 ) a proximate end (such as  328 ) of an atmosphere transport connector (such as  318 ) to a port (such as  322 ) in a housing (such as  104 ,  102 ) of the device (such as  100 ) and activating (such as  712 ) a pressurization mechanism (such as  108 ,  324 ) to actively transport atmosphere out of the internal compartment (such as  320 ) via the atmosphere transport connector (such as  318 ), and to actively transport the atmosphere from the test environment (such as  304 ) into the internal compartment (such as  320 ) of the device (such as  100 ) via a flow path (such as  316 ) in the housing (such as  104 ,  102 ).  
         [0061]    The method may further include placing (such as  706 ) the device (such as  100 ) in an environmental chamber (such as  302 ) having a target atmosphere meeting target criteria, and establishing (such as  710 ) the test environment (such as  304 ) in the environmental chamber (such as  302 ). The method may further include connecting (such as  708 ) a pump (such as  324 ) to a distal end (such as  326 ) of the atmosphere transport connector (such as  318 ), and activating (such as  712 ) the pump (such as  324 ) to pull atmosphere from the internal compartment (such as  320 ) of the substantially sealed device (such as  100 ).  
         [0062]    Another embodiment may be viewed as an environmental test system (such as  300 ) for performing environmental tests on a device (such as  100 ) having a housing (such as  102 ,  104 ) forming a substantially sealed internal compartment (such as  320 ), the housing having at least one void (such as  316 ) forming a flow path (such as  316 ) allowing atmosphere to flow there through. The environmental test system (such as  300 ) includes a port module (such as  408 ) attached to an opening (such as  322 ,  406 ) in the housing (such as  102  and  104 ). In a particular embodiment, the port module (such as  408 ) is attached to an atmosphere transport connector (such as  318 ) transport atmosphere to or from the internal compartment (such as  320 ), and/or a pressurization mechanism (such as  324  and  108 ) in fluid communication with the internal compartment (such as  320 ) of the device (such as  100 ) and the atmosphere transport connector (such as  318 ).  
         [0063]    One embodiment of the environmental test system (such as  300 ) includes a pump (such as  324 ) attached to a distal end (such as  326 ) of the atmosphere transport connector (such as  318 ), whereby the pump (such as  324 ) can pull atmosphere out of the internal compartment (such as  320 ). In another embodiment, spinning discs (such as  108 ) in a disc drive (such as  100 ) serve as the pressurization mechanism. In yet another embodiment, a controlled flow path module (such as  414 ) is included to create a desired flow rate in the device (such as  100 ) for simulating diffusion through the housing (such as  102  and  104 ) of the device (such as  100 ).  
         [0064]    It will be clear that the present invention is well adapted to attain the ends and advantages mentioned as well as those inherent therein. While a presently preferred embodiment has been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope of the present invention. The present invention may be implemented to environmentally test any substantially sealed device. For example, the present invention may be implemented to test avionics equipment, medical equipment, or other equipment that has an internal compartment that is substantially sealed to reduce deterioration from destructive elements. The destructive elements may be humidity or any other airborne elements, such as chemicals. In addition, in order to conduct environmental testing, the device under test need not be place in an environmental chamber; the systems and methods may be practiced anywhere it may be desirable to cause equilibration between atmosphere in an internal compartment of the device and atmosphere outside the device. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the invention disclosed and as defined in the appended claims.