Patent Description:
This application relates to further developments relative to the contents of <CIT>, the contents of which are published in <CIT>.

The above referenced publication discloses a sterilization container with a set of sensors and a processor. The sensors are configured to measure the characteristics of the environment in the antimicrobial barrier container. Signals representative of these measurements are sent to the processor. The processor evaluates these container environmental measurements. Using methods disclosed in the referenced publication, the processor verifies whether or not the instruments were properly sterilized. The processor then causes an indication regarding the sterilization state of the instruments to be output.

By using the above-described container, a medical facility is able to essentially almost immediately after the sterilization process, know whether or not the instruments were properly sterilized. This is more efficient than many sterilization systems which require the instruments to be held in quarantine for periods ranging from <NUM> to <NUM> hours in order to obtain the results of tests run to determine the state of sterilizing machine's operating characteristics that affect instrument sterility.

The above-described container includes a battery. The battery supplies the charge required to activate the processor as well as the typically one or more sensors that require electrical power to function. The system of the above referenced publication does not disclose any means to minimize the current draw on the battery. This would lead to having to take the sterilization container out of service on a frequent basis in order to either replace or recharge the battery.

Further, for some sterilization processes it is desirable to determine whether or not the instruments in the container are in a saturated steam environment. A saturated steam environment is one in which the majority of the gas in the chamber is water vapor (steam) with only trace amounts of the gases that normally make up air.

This determination is desirable because many instruments do not have unbroken smooth outer surfaces. An instrument may have one or more bores, notches or slots that have a closed end. These closed ends reduce contact with saturated steam on all surfaces of the instrument. Owing to the closed end nature of these void spaces, air may become trapped in these spaces. Due to the tendency of the air to be trapped in these spaces, it has proven difficult to determine whether or not an instrument is therefore completely surrounded by saturated steam.

<CIT> relates to a method for determining the sterilization conditions for surface sterilization adjacent a reference surface which is in communication with a sterilization space. The sterilant has only limited access to the reference surface, which for example inside an instrument, such as a lumen.

<CIT> relates to a disinfestation system for agricultural products, for example recovered tobacco, comprises a disinfestation unit which is releasably connected to plural containers.

Finally, <CIT> relates to a device for testing the effectiveness of a steam sterilization process in an autoclave using temperature measurements, comprising a base connected to sensors for determining the temperatures in the sterilization zone and in a measuring chamber, which is in air contact with the sterilization zone, respectively, the measuring chamber is at least partially reversibly removable from the base.

Herein below, several exemplary features are disclosed in relation to <FIG> to enhance better understanding of features of embodiments of the present disclosure according to the appended independent claim in <FIG>, in particular. Other examples than the embodiments of <FIG> may exhibit some, not all or none of the features according to the appended claims, but may still contribute to general principles underlying the claimed features.

An exemplary sterilization container <NUM> is now described by initial reference to <FIG> and <FIG>. The container <NUM> is formed from material that can be placed in a sterilizer and withstand the exposure to sterilants used to Sterilize surgical instruments. Container <NUM> includes a body <NUM> that is generally rectangularly shaped. Not identified are the front, rear, side and bottom panels that form the body <NUM>. The body <NUM> is closed at the bottom and open at the top. The body <NUM> is shaped to hold one or more surgical instruments <NUM>. The instruments <NUM> are seated on a rack <NUM> that is removably seated in the body <NUM>. A lid <NUM> is removably latched over the open top end of the body <NUM>. The lid <NUM> is formed with openings <NUM>. The openings <NUM> are openings into the container interior where sterilant is able to flow into and be withdrawn out of the container <NUM>. Not shown is the filter assembly mounted to the inner surface of lid <NUM>. This filter assembly is designed to allow the flow of sterilants in and out of the openings <NUM> while preventing airborne contaminates from entering the container <NUM> through the openings. The lid <NUM> is formed with an additional opening <NUM> that is spaced from the openings <NUM>. A window is disposed in opening <NUM> that allows transmission of visible light. The container <NUM> system described forms a barrier around the instruments that allows sterilant to enter and exit the container interior but prevents containments from entering the container. This barrier can be characterized as an anti-microbial barrier or a Sterile Barrier System (SBS).

The sterilization container <NUM> includes a sensor module <NUM>. In the illustrated version as seen in <FIG>, the sensor module <NUM> is shown attached to the inner surface of the container lid <NUM>. In <FIG>, for ease of understanding, the sensor module <NUM> is shown inverted from the position of the module when mounted to the container lid <NUM>. The sensor module <NUM> has a shell or frame <NUM>. Frame <NUM> consists of a number of panels that define the perimeter of the frame. Arbitrarily these panels include opposed front and rear panels <NUM> and <NUM>, respectively. Front panel <NUM> is longer in length and parallel to rear panel <NUM>. A substantially planar first side panel <NUM> extends between front panel <NUM> and rear panel <NUM> on one side of the frame <NUM>. Three side panels <NUM>, <NUM> and <NUM> form the side of the frame <NUM> opposite panel <NUM>. Panel <NUM> extends perpendicularly rearwardly away from the front panel <NUM>. Panel <NUM> extends approximately one-fifth the length of the frame <NUM>. Panel <NUM> tapers inwardly from the rear end of panel <NUM>. Collectively panels <NUM> and <NUM> extend approximately one-third the length of the frame <NUM>. Side panel <NUM> extends rearward from the free end of side panel <NUM> to rear panel <NUM>. The frame <NUM> is formed so that side panel <NUM> is parallel to side panel <NUM> and perpendicular to the rear panel <NUM>.

The frame is formed so that the bottom edges of the side panels <NUM> and <NUM> are elevated. More particularly, these edges are elevated where the panels extend over the lid openings <NUM>. This dimensioning facilitates the insertion and removal of the filter elements over the openings, as seen in <FIG> and <FIG>. The void space between the inner surface of lid <NUM> and panels <NUM> and <NUM> also functions as a through path that allows sterilant to flow through lid openings <NUM> over the sensor module <NUM> and into container body <NUM>.

The frame <NUM> is further formed to have a web <NUM>. The web <NUM> extends laterally across the frame between opposed side panels <NUM> and <NUM>. The web <NUM> is located immediately rearward of where panel <NUM> extends rearward from panel <NUM>. In some versions, the frame is formed as a two piece structure where two planar panels form abutting portions of web <NUM>. Not shown are the fasteners that hold the panels together.

Frame <NUM> further includes two base panels. A first base panel, panel <NUM>, extends between front panel <NUM> and web <NUM> and between side panel <NUM> and side panels <NUM> and <NUM>. Base panel <NUM> is formed to have a foot <NUM> that, as seen in <FIG>, that is recessed relative to the main portion of the base panel.

The second base panel, panel <NUM>, extends rearward from web <NUM> towards rear panel <NUM>. Base panel <NUM> extends between side panels <NUM> and <NUM>. While the base panel <NUM> extends towards the rear panel <NUM>, base panel <NUM> does not abut the rear panel <NUM>. Instead, the base panel <NUM> stops at a location forward of the rear panel <NUM> so as to define a gap <NUM>, identified in <FIG>, in the frame between the two panels <NUM> and <NUM>. Gap <NUM> allows the circulation of gases and liquids in the sterilization container into the portion of module <NUM> defined by panels <NUM>, <NUM>, <NUM>, <NUM> and web <NUM>.

Two tabs <NUM>, one seen in <FIG>, extend forward from the bottom edge of rear panel <NUM>. Each tab <NUM> is formed with two parallel slots <NUM>. Slots <NUM> terminate at a location rearward of the forwardly directed free ends of the tabs <NUM>.

When the sensor module <NUM> is mounted to the container lid <NUM>, the bottom surfaces of the front panel <NUM>, side panel <NUM>, the rear section of side panel <NUM>, the rear panel <NUM> and foot <NUM> are disposed against the inner surface of the lid <NUM>. The means by which the sensor module <NUM> is attached to the lid <NUM> is neither illustrated nor part of the present invention.

The frame <NUM> is formed with a number of openings. A number of these openings are in the frame side panel <NUM>. Two of the frame side panel <NUM> are openings are seen in <FIG>. A first one of the openings, opening <NUM>, extends laterally through the side panel. Opening <NUM> is threaded. A screw <NUM> seen in <FIG> is normally seated in opening <NUM> so as to seal the opening closed. The second opening seen in <FIG> includes a port <NUM>. Port <NUM> is circular in diameter and extends inwardly from the outer face of the side panel <NUM>. Port <NUM> opens into a bore <NUM> that extends to the inner surface of side panel <NUM>. Bore <NUM> has a cross sectional area greater than then that of port <NUM>.

A third opening in side panel <NUM> is seen in <FIG>. This third opening consists of four contiguous bores <NUM>, <NUM>, <NUM> and <NUM> that extend coaxially and diagonally through the side panel <NUM>. Bore <NUM> extends downwardly and outwardly from the inner surface of the side panel <NUM>. While not illustrated, the surface of the panel <NUM> that forms bore <NUM> is threaded. Bore <NUM> extends inwardly from the end of bore <NUM>. The side panel <NUM> is formed so that bore <NUM> is smaller in diameter than bore <NUM>. Bore <NUM> is smaller in diameter than bore <NUM> and extends outwardly and downwardly from bore <NUM>. Bore <NUM> extends from bore <NUM> to the outer surface of the side panel <NUM>. More particularly bore <NUM> opens up in the corner of the frame defined by the outer surface of the side panel and the adjacent perpendicular surface of the bottom of the panel. The side panel <NUM> is formed so that bore <NUM> has a diameter that is larger than the diameter of bore <NUM>.

From <FIG> it can be seen that side panel <NUM>. includes a fourth opening. This opening consists of a set of contiguous bore sections that collectively are identified as a single bore <NUM>. The adjacent bore sections that form bore <NUM> differ regarding whether or not they are threaded or smooth and in diameter. The bores of bore <NUM> are formed in a section of the side panel <NUM> that is stepped so as to have a lower top than the outer section of the panel. Bore <NUM> opens into the bottom of the side panel. A groove <NUM> in the undersurface of the side panel extends from the base of bore <NUM> to the outer surface of the side panel.

Three openings extend through web <NUM> as seen in <FIG>. Each opening consists of a bore <NUM> and a recess <NUM>. Only one of each of the bores <NUM> and recesses <NUM> are identified. The bores <NUM> extend rearward from the surface of the web that faces front panel <NUM>. The recesses <NUM> extend forward from the surface of the web <NUM> that faces the rear panel <NUM>. Each recess <NUM> extends to a complementary bore <NUM>. Each recess <NUM> subtends a cross sectional area greater than that of the complementary bore <NUM> In version, wherein web is formed from two abutting panels, bores <NUM> are formed as through openings in one panel and recesses <NUM> are formed as through openings in the second panel.

The frame base panel <NUM> is formed with an opening <NUM> seen in <FIG>. The opening <NUM> is formed in the panel foot <NUM>. The sensor module <NUM> is formed so that when the module is attached to the complementary container lid <NUM>, the opening <NUM> is in registration with the complementary sealed window <NUM> in the lid <NUM>. A window <NUM> is sealed to frame to prevent sterilant from entering the void space <NUM> defined partially by the base panel <NUM>. Window <NUM> is transparent to the type of energy emitted by a transmitter integral with the module. In the currently described version, this energy is photonic energy, namely visible light. Accordingly, in this version the window <NUM> is transparent to visible light.

Frame <NUM> is formed with additional openings that accommodate fasteners. Some of these fasteners hold panels and other parts of the frame <NUM> to each other. Other ones of these fasteners hold components mounted in the frame <NUM> to the frame. The openings in which these fasteners are fitted are neither described nor identified. Also not called out are the sections of the frame where the panels are relatively thick in order to accommodate these openings and provide added structural strength to the frame.

Two covers <NUM> and <NUM> are secured over the frame <NUM>. When the module <NUM> is disposed in the sterilization container with which the module is used it is understood that the covers <NUM> and <NUM> project downwardly from the container lid <NUM>. Cover <NUM> extends over the void space <NUM> in the frame defined by the front panel <NUM>, the portion of side panel <NUM> adjacent the front panel, side panel <NUM> and web <NUM>. Cover <NUM> is removably held to the frame by fasteners not identified. The cover <NUM> is held to the frame so that the void space below the cover is sealed from exposure to gases that are introduced into the container during a sterilization process. These gases, depending on the sterilization process, can include one or more of the following: water vapor (steam); hydrogen peroxide; ethylene oxide; and ozone. To provide this seal an O-ring <NUM>, identified in <FIG>, is sandwiched between the frame <NUM> and the cover <NUM>.

Cover <NUM> extends over the portion of the frame that extends rearward from web <NUM>. Thus the cover <NUM>, front-to-rear, extends between web <NUM> and rear panel <NUM>. Side-to-side the cover <NUM> extends between the portion of side panel <NUM> located rearward of web <NUM> and side panel <NUM>. Cover <NUM> is formed with openings <NUM>. Openings <NUM> and gap <NUM> adjacent frame panels <NUM> and <NUM> allow sterilants introduced into the sterilization container to circulate the space <NUM> in the container defined by panels <NUM>, <NUM>, <NUM> and web <NUM>. The cover <NUM> also prevents inadvertent contact with the components of the sensor of module <NUM> disposed in the space <NUM>.

Sensor module <NUM> includes a temperature sensor the assembly of which is now described by reference to <FIG>. The actual temperature sensitive transducer is a thermistor <NUM>. Thermistor <NUM> is encased in a tube <NUM> formed from material that is thermally conductive and will not corrode when exposed to the sterilants introduced into the sterilization container. In some versions, tube <NUM> is formed from aluminum. Tube <NUM> is closed at the outer end, the end of the tube that projects out of frame <NUM>. The tube <NUM> also has a diameter less than the diameter of frame bores <NUM>, <NUM>, <NUM> and <NUM>. The tube <NUM> has a wall thickness that is relatively thin so as to facilitate the rapid conduction of heat through the tube and to the thermistor. In versions, in which the tube is formed from aluminum, the tube may have a maximum wall thickness of <NUM>. In another embodiment, the thermistor is potted to the tube walls with a thermally conductive material.

Thermistor <NUM> and tube <NUM> are seated in frame bores <NUM>, <NUM>, <NUM> and <NUM>. Not identified is the wire that extends from thermistor <NUM> out of the open end of tube <NUM>. More particularly, tube <NUM> extends through a ferrule <NUM> and a fitting <NUM>, both of which are made from plastic with a low thermal conductivity, a thermal conductively lower than that of tube <NUM>. Ferrule <NUM> has a circular base, not identified, that is seated against the step that forms the transition between bores <NUM> and <NUM>. The ferrule has a head that is conically shaped that extend from the base into bore <NUM>. A bore, not identified, extends through the ferrule. The fitting <NUM> has a threaded stem and a head that is larger in diameter than the stem. The fitting stem is dimensioned so the fitting threading can engage the threading around bore <NUM>. A bore, not identified, extends axially through the fitting <NUM>. The fitting <NUM> is further formed so that at the end of the stem, the bore opens into a conically shaped counterbore.

The temperature sensor assembly is attached to the sensor module <NUM> by placing the thermistor <NUM> in the closed end of tube <NUM>. Not seen are the conductors that extend to the thermistor. The ferrule <NUM> is seated in bore <NUM> and tube <NUM> inserted through the bore in the ferrule <NUM>. Fitting <NUM> is threaded into bore <NUM>. The initial positioning of the fitting <NUM> in bore <NUM> results in the positioning of the tube <NUM> in the bore that runs through the fitting. The screwing of the fitting <NUM> into bore <NUM> compresses the fitting against the ferrule <NUM>. The compression of fitting <NUM> against the ferrule causes the ferrule <NUM> to both compress inwardly around tube <NUM> and outwardly against the wall of the frame <NUM> that defines bore <NUM>. This compression of the ferrule <NUM> thus creates a vacuum tight seal between the frame <NUM> and the tube <NUM> and securely holds the tube to the frame.

When sensor module <NUM> is assembled, the closed end of the tube <NUM> is spaced inwardly from the inner cylindrical wall of the frame <NUM> that defines bore <NUM>. This ensures that sterilant circulates freely around the end of the tube, the portion of the tube in which the thermistor <NUM> is located. Further, owing to ferrule <NUM> and fitting <NUM> being formed of material that has a relatively low thermal conductivity, tube <NUM> is to some extent thermally isolated from module frame <NUM>. This minimizes the extent to which the temperature of the thermistor is affected by the temperature of the frame <NUM>. The thermistor <NUM> acquires a temperature that essentially is identical to the temperature of the environment inside the sterilization container. Also, when the sensor module <NUM> is assembled, the tube <NUM> in most versions does not project outside of bore <NUM>. This substantially eliminates the likelihood that an instrument in the container or the misplacement of finger can potentially damage the tube that, owing to the thinness of its wall, is relatively fragile.

Two pressure sensitive transducers <NUM> and <NUM>, manometers, are mounted to the inner surface of frame side panel <NUM> as seen in <FIG>. Transducers <NUM> and <NUM> are located adjacent panel bore <NUM>. A shell <NUM> is disposed around the transducers <NUM> and <NUM>. The shell <NUM> is secured to the side panel <NUM> so there is a hermetic seal at the interface between the surface of the panel and the shell. Since the seal extends circumferentially around the portion of the panel <NUM> that defines bore <NUM>, the seal prevents the fluids (liquid and gaseous) in the container from entering the void space in the module beyond the shell <NUM>.

In some versions, both pressures sensors <NUM> and <NUM> are capacitor type transducers. The capacitance of the sensor <NUM> or <NUM> varies as a function of the ambient absolute pressure. A first one of the sensors, arbitrarily sensor <NUM>, provides relatively accurate measurements of ambient absolute pressure for relatively high pressures. For the desired purposes a high pressure is a pressure above a minimum pressure of <NUM> mBar to <NUM> mBar (<NUM> to <NUM> Torr). The second pressure sensor, sensor <NUM>, provides relatively accurate measurements of absolute pressure for relatively low pressures. For the desired purposes, a relatively low pressure is a pressure below a maximum pressure of between <NUM> mBar and <NUM> mBar (<NUM> and <NUM> Torr). Pressure sensor <NUM> provides accurate measurements of pressure to a pressure of <NUM> mBar (<NUM> Torr), more ideally to at least <NUM> mBar (<NUM> Torr) and more ideally still to <NUM> mBar (<NUM> Torr). Not shown are the conductors that extend from sensors <NUM> and <NUM> through shell <NUM>.

A one-way pressure-trigged valve <NUM>, seen in <FIG> is mounted in the bores that collectively form bore <NUM>. Valve <NUM> opens when the pressure in frame void space <NUM> is greater than the ambient pressure. In some versions, the valve <NUM> is set to open when the pressure difference is between <NUM> and <NUM> Atmospheres. In other versions, valve <NUM> is set to open when the pressure difference is between <NUM> and <NUM> Atmospheres.

Valve <NUM> opens when, during a sterilization process, the container is exposed to an environment in which the pressure is substantially below atmospheric pressure. The opening of valve at least partially reduces the pressure differential between the environment and void space <NUM>. This reduction in pressure difference reduces the mechanical stress on the components forming the sensor module as well as the seals between these components.

After sterilization of the contents of the container is complete, the container is returned to the ambient, room, environment. When the container is in this environment, the pressure in void space <NUM> is less than the ambient pressure. This pressure difference is typically less than <NUM> to <NUM> Atmospheres. This pressure difference does not induce appreciable mechanical stress in the components forming the sensor module <NUM>.

There may be times during the life of the sensor module <NUM> when it is necessary to access the components in void space <NUM>. To so access these components, screw <NUM> is removed from bore <NUM>. The removal of screw <NUM> allows the pressure in the void space to equalize with the ambient air pressure. This reduces the effort required to remove cover <NUM>.

Two light emitting devices <NUM> and <NUM>, are attached to web <NUM>. In some versions, devices <NUM> and <NUM> are LEDs. The LEDs <NUM> and <NUM> are each mounted in a separate one of the bores <NUM> formed in the web <NUM>. Each LED emits light that includes light at wavelength that is absorbed by one of the gases or vapors that may be present inside the container <NUM> during a sterilization process. Two gases, vapors, that may be introduced into the container may be vaporized water and vaporized hydrogen peroxide. Versions of the sensor module <NUM> designed for use with this container will have one LED, arbitrarily LED <NUM> capable of emitting light within a range that includes the <NUM> wavelength, the wavelength of light absorbed by water vapor. The second LED <NUM> emits light within a range that includes the <NUM> wavelength, the wavelength of light absorbed by vaporized hydrogen peroxide. Both LEDs <NUM> and <NUM> are oriented to emit light towards the frame rear panel <NUM>.

A photodetector <NUM> is also attached to web <NUM>. The photodetector <NUM> is seated in the center located bore in the web <NUM>. Photodetector <NUM> is capable of emitting a signal that varies as a function of the intensity of the light at wavelengths of the light absorbed by the gases/vapors the concentrations of which are to be measured. The photodetector <NUM> is positioned in the block so the light detecting surface of the sensor is oriented towards the rear panel <NUM>.

Three temperature-sensitive transducers <NUM>, <NUM> and <NUM>, shown only in the block diagram of <FIG> are also mounted to web <NUM>. In some versions, transducers <NUM>, <NUM> and <NUM> are thermistors. Transducer <NUM> is mounted to web <NUM> to provide a measurement representative of the temperature of LED <NUM>. Transducer <NUM> is mounted to the web <NUM> to provide a measurement of the temperature of photodetector <NUM>. Transducer <NUM> is mounted to the web <NUM> to provide a measure of the temperature of LED <NUM>.

A window is seated in each of the recesses <NUM> formed in web <NUM> as seen best in <FIG>. Each window is mounted to the web <NUM> in such a way that the window provides a transparent barrier between space <NUM> and LED <NUM> or <NUM> or photodetector <NUM> covered by the window. A first window, window <NUM>, is seated in the recess <NUM> disposed around LED <NUM>. Window <NUM> is formed of material that filters outs substantially all light other than the light absorbed by water vapor. Window <NUM> is seated in the recess disposed around the photodetector <NUM>. Window <NUM> is formed from material that is highly transparent to range of wavelengths of the light absorbed by water vapor and the vaporized hydrogen peroxide. Window <NUM> is seated in the recess <NUM> disposed around LED <NUM>. In some embodiments, the window <NUM> is formed from material that filters out substantially all light other than light of the wavelength absorbed by vaporized hydrogen peroxide.

A heating element <NUM>, represented by a resistor in <FIG>, is mounted to web <NUM>.

Two concave mirrors <NUM> and <NUM> are adjustable mounted to the rear panel <NUM> of the frame <NUM>. As identified with respect to mirror <NUM>, a fixed plate <NUM> and a moving plate <NUM> is associated with each mirror. Each pair of plates <NUM> and <NUM> are disposed over one of the tabs <NUM> that project forward of the rear panel <NUM>. The position of the plates along the tab <NUM> is adjustably locked by means of set screws (not illustrated) that seats in the tab slots <NUM>. Rigid plate <NUM> is located between the rear panel <NUM> and the moving plate <NUM>. Adjustment screws <NUM> (two screws identified) that extend between plates <NUM> and <NUM> allow the angular orientation of the moving plate <NUM> to be adjusted relative to the fixed plate <NUM>. Each mirror is bonded to, attached to or formed as part of the moving plate with which the mirror is associated. The ability to move the plates along the tabs allows the positions of the mirrors within space <NUM> to be adjusted. The ability to set the orientation of the moving plates relative to the rigid plates allows the orientation of the mirrors to be adjusted.

Mirror <NUM> is positioned to reflect the light emitted by LED <NUM> to the photodetector <NUM>. Mirror <NUM> is positioned to reflect the light emitted by LED <NUM> to the photodetector <NUM>. Generally, the components forming the sensor module <NUM> are selected so that mirrors have focal points that are one-half the distance from where the LEDs <NUM> and <NUM> are located to the mirrors.

A heating element <NUM> is attached to each moving plate <NUM>. In the drawings the heating elements <NUM> are represented by a single resistor in <FIG>. The means by which the heating elements <NUM> are attached to moving plate <NUM> is not part of the present invention.

<FIG> and <FIG>, when assembled together, form a block and partial schematic diagram of the components of the sensor module <NUM>. These components include a battery <NUM>. The battery <NUM> that provides the power to the other components of the module. The battery <NUM> may consist of plural cells, (individual cells not identified.

A voltage regulator <NUM> is connected to the battery <NUM>. Voltage regulator <NUM> provides constant voltages at the appropriate voltage levels to the components internal the module that require these voltages. To avoid the complexity of the Figures, with one exception discussed below, the connections from which the voltages are supplied to the components internal to the module <NUM> are not illustrated.

Two constant current sources <NUM> and <NUM> are also connected to battery <NUM>. Current sources <NUM> and <NUM> selectively turned on and off. Current source <NUM> is the source of the current that is applied to LED <NUM>. Current source <NUM> is the source of current that is applied to LED <NUM>. Not shown are the load resistors in series with the LEDs <NUM> and <NUM>.

A selectively turned on/off voltage source <NUM> is also connected to the battery. The voltage output by source <NUM> is supplied to heating elements <NUM> and <NUM>.

Sensor module <NUM> also contains a processor <NUM>. Processor <NUM> monitors and records the environmental measurements made by the module transducers. Not identified is the memory integral with the processor <NUM> in which these measurements are stored. The processor also controls the operation of at least some of the electrically activated components of the module. In some versions, the processor monitors the environmental characteristics measured by the sensors. Based on the measured environmental characteristics, the processor <NUM> provides an indication regarding whether or not the surgical instruments disposed in the container <NUM> were properly sterilized.

In Figures the signals representative of temperatures measured by thermistors <NUM>, <NUM>, <NUM>, and <NUM> are shown as being applied to processor <NUM> as input signals. Also applied to the processor as input signals are signals representative of container pressure as output by the pressure transducers, <NUM> and <NUM>. The signal representative of the light measured photodetector <NUM> is also sourced to the processor as an input signal.

In the Figures, a connection is shown from voltage source <NUM> to pressure transducer <NUM>. This is to represent that for each of thermistors <NUM>, <NUM><NUM> and <NUM> as well as the remaining pressure transducer <NUM> and photodetector <NUM>, a potential is supplied to the transducer in order for the transducer to operate. A switch, represented by MOSFET <NUM>, is in series between the voltage source <NUM> and the pressure transducer <NUM>. This switch controls the application of the potential required to activate the transducer <NUM>. Processor <NUM> is shown connected to the gate of MOSFET <NUM>. This is to represent that the processor <NUM> controls the application of the potential to the pressure transducer <NUM>. While not shown it should be understood that the processor <NUM> controls the application of the potentials required to energize the transducers and sensor components.

Connections are also shown extending from the processor <NUM> to current sources <NUM> and <NUM> and voltage source <NUM>. These connections represent that the processor <NUM> controls the sourcing of the current from the current sources <NUM> and <NUM> and the on/off state of voltage source <NUM>. The on/off state of voltage source <NUM> is controlled to, by extension, control the energization of heating elements <NUM> and <NUM>.

The processor <NUM> is configured to source data to outside of the sterilization container <NUM>. These data are based on the measurements made by the transducers integral with the sensor module <NUM>. In the illustrated version, these data are sourced by the selective actuation of two LEDs <NUM> and <NUM>. LEDs <NUM> and <NUM> are mounted in void space <NUM> so that light they emit is visible through module window <NUM> and lid opening <NUM>. The LED <NUM> emits green light. The LED <NUM> emits red light.

The initial operation of sensor module is now explained by reference to <FIG>. For the majority of the time the container <NUM> and, by extension, the module <NUM>, are in an ambient room environment. To conserve the draw of charge from battery <NUM>, the module operates in a sleep state, represented by step <NUM>. When in the sleep state the processor <NUM> operates in a state in which only minimal power is drawn by the components internal to the module <NUM>. One subcircuit integral with the processor that does receive power is the clock circuit (circuit not illustrated). When the module is in the sleep state, the potentials needed to activate the temperature, pressure and light transducers are not sourced. Current sources <NUM> and <NUM> are in the off state.

Periodically, based on the elapsed time indicated by the clock circuit, the module enters a peek state, step <NUM>. When the module <NUM> is in the peek state, the processor enters a higher power consuming state than when in the sleep state. When in the peek state, the processor <NUM> actuates the transducers that provide an indication regarding whether or not the sterilization container <NUM> may have been placed in a sterilizer and is being subjected to a sterilization process. The transducers that are actuated when the module <NUM> is in the peek state are the sensors that would provide measurements indicating that, as a result of the initiation of the sterilization process, the environment inside the sterilization container <NUM> has significantly changed from the room temperature environment. A typical sterilization process starts with either the heating of gases inside the sterilization container <NUM> or the drawing down of the pressure inside the container. Accordingly, in the execution of the peek state step of this type of the container the processor asserts the command that results in the activation of either the thermistor <NUM> or pressure transducer <NUM>. The signal representative of the sensed environmental characteristic is applied to the processor <NUM>.

Step <NUM> represents the evaluation by the processor of the environmental measurement made when the module is in the peek state. For example, if the sterilization process is one in which the initial step of the process is the heating of the container, step <NUM> is the determining whether or not the container temperature, as measured by thermistor <NUM> is appreciably above room temperature, for example greater than <NUM>. If the sterilization process is one in which the initial step of the process is the drawing of a vacuum in the sterilization container <NUM>, step <NUM> is the determining whether or not the signal from pressure transducer <NUM> indicates that the container absolute pressure has dropped to below <NUM> mBar (<NUM> Torr), approximately <NUM> mBar (<NUM> Torr) below atmospheric pressure.

Processor <NUM> interprets the evaluation of step <NUM> testing false as an indication that the sterilization container is not being subjected to a sterilization process. The processor <NUM> then returns to the sleep state as represented by the loop back to step <NUM>. As part of this loop back the transducer used to determine whether or not the container <NUM> is being sterilized is turned off and the processor returns to the low power consuming mode. In many versions, it is anticipated that the module will enter transition from the sleep state to the peek state once every <NUM> to <NUM> minutes. The processor will take approximately <NUM> to <NUM> milliseconds to make the determination regarding whether or not the sterilization container is being subjected to a sterilization process.

Alternatively, the environmental analysis of step <NUM> may indicate that the sterilization container is being subjected to a sterilization process. If this analysis tests true, the sensor module <NUM> enters an active state, step <NUM>. In the active state the processor <NUM> is in a state in which the processor draws more charge than when in the sleep state. When in the active state, the processor may draw more power than when in the peek state. Also, depending on the time it takes a particular transducer to enter a stable state after being actuated, the processor may assert the control signals that result in the simultaneous application of activation voltages to different transducers. Thus, thermistors <NUM>, <NUM>, <NUM> and <NUM> and pressure transducers <NUM> and <NUM> may each need to be turned on for a period of at least <NUM> second before they output steady state signals. In this situation, the processor asserts the signals that cause the simultaneous application of the potentials needed to turn on these transducers simultaneously.

Also as part of the entry into the active state, the processor actuates the heating elements <NUM> and <NUM>. The heating elements <NUM> and <NUM> are actuated by the assertion of command to voltage source <NUM> that results in the voltage source sourcing energization signals to the heating element <NUM> and <NUM>. The thermal energy output by heating elements <NUM> heats the windows <NUM>, <NUM> and <NUM>. The thermal energy output by heating elements <NUM> heats the mirrors <NUM> and <NUM>. The heating of windows <NUM>, <NUM> and <NUM> and mirrors <NUM> and <NUM> places these components of the module at a temperature that is above the condensation temperature of the vapors inside the container <NUM>. When vapors (gases) are introduced into space <NUM> the fact that these components are at a temperature above the condensation temperature substantially eliminates the condensation of these vapors on these components.

<FIG> represents the monitoring of the environment inside the container <NUM> when module <NUM> is in the active state. Step <NUM> represents the reading of the signal output from thermistor <NUM> to determine temperature inside the container <NUM>. Step <NUM> represents the reading of the signal output from pressure transducer <NUM> or <NUM> to determine pressure in the container <NUM>. The pressure reading accepted as container pressure by the processor is a function of the predetermined low boundary pressure. If the pressure is above the low boundary, the signal representative of pressure from transducer <NUM> is employed as the signal representative of container pressure. If the pressure appears to be at or below the low boundary, the signal representative of pressure sourced by transducer <NUM> is employed as the signal representative of container pressure.

During a sterilization process different gases may be simultaneously or consecutively introduced into the sterilization container <NUM>. For one sterilization process, it is necessary to obtain essentially simultaneous measurements of the concentrations of water vapor and vaporized hydrogen peroxide in the container. It should be understood that each of the gases for which a concentration measurement may be required may not actually all be sterilants. A particular gas may be a byproduct of the production of the sterilant. Alternatively, the gas may be a gas that exists in the ambient environment. However, to verify the effectiveness of some sterilization processes, it is necessary to know the concentration levels of these gases that do not contribute to the sterilization process. For example, to determine the effectiveness of a process in which hydrogen peroxide is the sterilant, it is desirable to know the essentially simultaneous concentration levels of both the vaporized hydrogen peroxide and the vaporized water in the sterilization case.

The concentration of gas in a space is related to the fraction of light absorbed by the gas in the space at a specific wavelength for that gas. Module <NUM> measures the absorption of light at the specific and different wavelengths associated with gases for which it is necessary to determine their concentrations. These measurements start with the not illustrated step of the application of a potential from voltage source <NUM> to the photodetector <NUM> to turn on the photodetector. Depending on the particular structure of the photodetector <NUM>, the photodetector may be turned and held on as part of the placing of the sensor module in the active state. Alternatively, as part of the below described steps <NUM> and <NUM> the photodetector may be momentarily turned on when each of LEDs <NUM> and <NUM> are turned on. In these versions, the photodetector is typically turned on for at least <NUM> milliseconds prior to the turning on of the LED <NUM> or <NUM>.

Step <NUM> represents the measuring of the concentration of the first gas, here water vapor. Step <NUM> is executed by processor <NUM> asserting a signal to the current source <NUM> that results in the source apply current to LED <NUM> that results in the emission of light by the LED. The emitted light is transmitted through web <NUM> and window <NUM>. From window <NUM> the light is applied to mirror <NUM>. From mirror <NUM> the light is reflected through window <NUM> to photodetector <NUM>. The quantity of the light that strikes the photodetector is inversely related to the absorption of light by the water vapor. Therefore, the signal output by the photodetector in step <NUM> represents a measurement of the concentration of water vapor in the sterilization container. The execution of step <NUM> concludes with the turning off of current source <NUM> and the resultant turning off of LED <NUM>.

During the execution of step <NUM>, the processor <NUM> also asserts the appropriate control signals so the processor is able to obtain the temperature measurements from thermistor <NUM>, the temperature sensor associated with LED <NUM> and thermistor <NUM>, the temperature sensor associated with the photodetector <NUM>. During the processing of the signal from the photodiode <NUM>, the processor <NUM> uses these temperature measurements to compensate for variations in the light emitted and the light detected as a result of variations in temperature of the components with which these temperature sensors are associated.

A step <NUM> is the measuring of the concentration of a second gas, in this example vaporized hydrogen peroxide. In step <NUM> the processor <NUM> asserts the command signal to current source <NUM> that results in the current source turning on. Current source <NUM>, when active, asserts the current to LED <NUM> required to cause the LED to emit light in the wavelength that is absorbed by vaporized hydrogen peroxide. The light emitted by LED <NUM> passes through the web <NUM> and window <NUM> to mirror <NUM>. The light is reflected by the mirror <NUM> through window <NUM> to the photodetector <NUM>. In step <NUM> the signal output by the photodetector <NUM> and applied to the processor <NUM> functions as a measure of concentration of vaporized hydrogen peroxide in the sterilization container <NUM>. Step <NUM> concludes with the negating of the command signal from the processor <NUM> that holds current source <NUM> in the on state. The turning off of the current source <NUM> results in the turning off of LED <NUM>.

During the execution of steps <NUM> and <NUM> processor <NUM> also asserts the appropriate control signals so the processor is able to obtain the temperature measurements from thermistor <NUM> and thermistor <NUM>, the temperature sensor associated with the LED <NUM>. During the processing of the signal from the photodiode <NUM>, the processor uses these temperature measurements to compensate for variations in the light emitted and the light detected as a result of variations in temperature.

The sensor module repeatedly makes the above-described measurements of the characteristics of the environment internal to the sterilization container <NUM>. In <FIG> this is represented by the loop back from step <NUM> to step <NUM>-. In practice, the measurements taken during steps <NUM>-<NUM> are taken with a frequency of between <NUM> and <NUM> and more often at a frequency between <NUM> and <NUM>. In the period in which any single set of measurements are taken, each LED <NUM> and <NUM> is turned on for a phase that last less than <NUM>% of the total period, usually less than <NUM>% of the total period and more ideally less than <NUM>% of the total period. The frequency with which these measurements are taken are understood to be greater than the frequency at which the processor transfers from the sleep state to the peek state.

The evaluation of the container environmental characteristics is now explained by reference to the flow chart of <FIG>. Initially it should be understood that the steps of evaluating the characteristics are typically integrated with the above-described steps of measuring the environmental characteristics.

Step <NUM> is the step of evaluating the measured environment characteristics to determine whether or not the sterilization process was satisfactorily completed. The specific sub-steps of step <NUM> are not part of the present invention. For the purposes of understanding how module <NUM> function it can be generally understood that the one or more sub-steps of step <NUM> often involves making at least one comparison of an environmental measurement made by one of the module sensors to a validated process measurement. A "validated sterilization process" is understood to be a sterilization process that, based on past testing, is known to sterilize a particular instrument to a sterility assurance level that essentially ensures any microbial material on the instrument would be innocuous. A surgical instrument is often considered sterilized if the instrument has a sterility assurance level (SAL) of <NUM>-<NUM>. This means there likelihood that if the microorganism population on the instrument was reduced by at least <NUM>%. The above referenced <CIT>, provides an explanation of how to obtain environmental measurements for a validated sterilization process.

A validated sterilization process for the instrument in the container <NUM> may be one which the instrument is subjected to concentration of <NUM>/l vaporized hydrogen peroxide at a temperature of at least <NUM> for a period of at least <NUM> minutes. As described in the above referenced <CIT> the data describing these validated sterilization process measurements are preloaded into the memory integral with the processor <NUM> prior the start of the sterilization process. The means of loading these data are not part of the present invention.

When the above measurements are the validated sterilization process measurements for the instrument, in step <NUM> the processor evaluates the environmental measurements made by the sensors to determine, if for a period of at least <NUM> minutes, the vaporized hydrogen peroxide in the container was measured to have a concentration of at least <NUM>/l while the temperature inside the container was at least <NUM>.

Step <NUM> represents the outputting of information by the module based on the evaluations performed in step <NUM>. In the described version, the processor <NUM> outputs the information by selectively turning on one of the two LEDs <NUM> or <NUM>. If the evaluation of step <NUM> tests positive, then the instrument in the container <NUM> was sterilized to an acceptable SAL. In this situation the processor <NUM> asserts the command signal that results the LED <NUM> emitting green light. A negative result for the evaluation of step <NUM> is an indication that the there is a likelihood that instrument in the container <NUM> was not sterilized to an acceptable SAL. In this situation, processor <NUM> asserts the command signal that results in LED <NUM> emitting red light. The light the facility personnel see emitted through module window <NUM> and lid opening <NUM> thus provides an indication regarding whether or not the instrument in the container was acceptably sterilized.

Step <NUM> is the evaluation by the processor to determine whether or not the sterilization container <NUM> was removed from the sterilizer and return to an ambient environment, sometimes called a room environment. The evaluation of step <NUM> may be performed by the continued measuring of the container temperature and pressure. In one implementation the processor interprets environmental measurements that the container has been at room temperature and room pressure for a period of time of at least <NUM> minutes as an indication that the sterilization process is completed and the container and the instrument in the container back in a room environment. The loop back if this evaluation tests negative represents that the processor <NUM> repetitively makes the evaluation of step <NUM> until the evaluation tests positive.

After some elapse of time after the sterilization process is completed, the evaluation of step <NUM> tests positive. Processor <NUM> responds to this positive test by in step <NUM> by placing the module in the sleep state. The module returns to step <NUM>. The processor stops the sourcing of power to the transducers that is required in order for the sensors to make the required active state environment measurements. After a sterilization process is completed and the module returns to the sleep state the appropriate LED <NUM> or <NUM> remains on. This provides an indication of whether or not the instrument <NUM> in the container <NUM> has been properly sterilized.

Sterilization container <NUM> provides data regarding the environment inside the container while the container and the one or more instruments in the container are being sterilized. The container relies on a battery <NUM> integral with the container source the power needed to operate the sensors and data logging components in the container. This eliminates the need to, when the container is in a sterilizer, provide a power connection from the sterilizer to the container. During the large blocks of time the sterilization container is not subjected to a sterilization process, the power drawn by the power consuming components in the container is kept to a minimum. When the container is subjected to a sterilization process, the power required to actuate at least some of the environmental sensors is only supplied to these sensors in spaced apart duty cycles. The cumulative time of these individual duty cycles is less than the time period required to perform the sterilization process. This regulating of when the sensors internal to the sterilization case are energized conserves the charge stored in the battery <NUM>. The conservation of battery charge reduces the frequency with which the battery <NUM> needs to be replaced or recharged.

Further some light emitting components have a life time that is at least partially a function of the amount of time the components are actuated. By not always actuating the light emitting components associated with vapor measuring assemblies, the lifetimes of the components can be extended.

Container <NUM> is further designed so that a single photodetector <NUM> is all that is required to measure the concentrations of plural different gasses and vapors. This version eliminates the need to provide a separate photodetector for each wavelength of the light that intensity of which should be measured. This feature eliminate more than the cost of the plural photodetectors. This feature also eliminates the need to provide space for plural light paths so the light emitted by each light source travels to a detector specific for that light source.

An alternative means of determining the concentration of the gas (or gasses) for which this information is needed to evaluate the effectiveness of the sterilization process is now described by reference to <FIG>. The process of <FIG> is explained by reference to how the concentration of hydrogen peroxide gas can be determined. The method may be integrated with the methods of <FIG>. In this method, the sterilization container <NUM> is initially placed in the sterilizer (step not shown). Prior to the introduction of any sterilizing gases, a vacuum is drawn on the sterilizer chamber in which the container <NUM> is placed, step <NUM>. More particularly, in step <NUM>, the vacuum is drawn so the chamber is close to gas free as possible, a chamber pressure of <NUM> mBar (<NUM> Torr) or less. This results in the evaluation of steps <NUM> and <NUM> placing the sensor module in the active state.

Once the vacuum is drawn, in a step <NUM>, a measurement is made of the intensity of the light emitted by LED <NUM>. Step <NUM> is executed by turning on LED <NUM> and the photodetector using the sub-steps described with regard to step <NUM>. This initial measurement of detected light is referred to as I<NUM>.

After the initial measurement of light intensity is made the sterilization process proceeds, step <NUM>. Step <NUM> it is understood includes the introduction of the sterilant into the sterilization chamber.

Step <NUM> is the measurement of the gas to determine the concentration of the gas during the actual sterilization process. This process is a re-execution of the sub-steps performed in step <NUM> in order to determine the intensity of the light sensed by the photodetector. This measurement of light intensity is referred to as IA.

Step <NUM> is the calculation of the concentration of gas measured in step <NUM>. More particularly, in step <NUM> the processor using the Beers-Lambert law where C, the concentration of gas is determined according to the following formula: <MAT> where K is a constant.

As discussed above, in most sterilization processes it is anticipated that it is necessary to determine the concentration of one or more gases repeatedly over time period. To make these plural determinations of gas concentration, steps <NUM> and <NUM> are repeatedly executed. This is represented by the loop back from step <NUM> to step <NUM>. Not shown are the process steps executed by the processor <NUM> to determine that it is no longer required to make the measurements needed to determine gas concentration. One variable that may be employed to make this determination is the elapsed time since the occurrence of some event during the sterilization process.

The method of determining gas concentration according to the method of <FIG> is not based on an absolute measurement of light intensity. Instead, this method is based on the relative difference between two measurements made during the same sterilization cycle. This method compensates for changes in the characteristics of the light emitted by the LED <NUM> and changes in the sensitivity of the photodetector <NUM>. The method also compensates for changes in the physical structure of the components that reflect the light, mirror <NUM>, and through which the light travels, window <NUM>.

The same method may be used for determining the concentration of water vapor. In this execution of steps <NUM> and <NUM>, the measurements of intensity of the light emitted by LED <NUM> are the measurements used to determine variables I<NUM> and IA.

It is a further feature of this version that each execution of step <NUM> to determine the intensity of the light when gas is present does not have to be immediately followed by the companion execution of step <NUM>. In some versions, the plural measurements of light intensity IA obtained in the plural executions of step <NUM> are stored. Each one of these measurements may be stored with a time stamp indicating the time the measurement was made. After the sterilization cycle is completed, the processor <NUM>, in the plural executions of step <NUM> uses the plural IA values and the single I<NUM> value to calculate the concentration of gas during the time period of interest.

By not executing step <NUM> after each execution of step <NUM> the sensor module does not have to be run in the fully active mode for the time needed to execute step <NUM>. Here the fully active mode is understood to be the mode in which not only the processor <NUM> is fully operational but the components used to determine light concentration are also actuated. But not having to run in the fully active mode when performing the processing steps needed to determine gas concentrations the module draws less charge on the battery <NUM> than would be drawn if these determinations are made when the module <NUM> is in the fully active mode.

While not illustrated in <FIG> as part of executing step <NUM>, the temperatures of the LED <NUM> or <NUM> is measured and recorded. The temperature of photodetector <NUM> is also measured and recorded. Each time a step <NUM> is executed the temperatures of the LED <NUM> and <NUM> and the photodetector <NUM> are also measured and recorded. As part of the process of generating the IA values the difference in LED and photodetector temperatures between when the I<NUM> and IA measurements are made are used to adjust for differences in the output of LED and the sensitivity of the photodetector.

In the first described method of determining light intensity, the output signal from the photodetector <NUM> is adjusted to compensate for variations in signal strength due to variations in temperature of the photodetector. The temperature signal from thermistor <NUM> is employed as a measure of the temperature when these calculations are performed.

In an alternative version, variations in signal strength of the photodetector <NUM> may be compensated for without using a measure of photodetector temperature as an input variable. In this version, as represented by step <NUM> of <FIG>, prior to the introduction of any sterilant into the container and prior to the actuation of LED <NUM> or LED <NUM> that emits light the concentration of which is measured, the signal output from the photodetector <NUM> is read. This signal is considered to have a strength D0 • The LED <NUM> or <NUM> is then actuated. If the process of <FIG> is combined with the process of <FIG>, step <NUM> would be the next executed step. In other words, as a result of the actuation of the LED <NUM> or LED <NUM> the necessary I<NUM> measurement is obtained.

During the sterilization process it is still necessary to obtain the IA measurements of light intensity in order to determine gas concentration. Prior to making each one of these measurements, prior to each execution of step <NUM>, a step <NUM> is executed. In step <NUM> the signal output by the photodetector without any light being shined directly on the photodetector is measured. This signal is considered to have strength of D<NUM>. After the DA measurement is obtained, the LED <NUM> or <NUM> is actuated and the signal output by the photodetector <NUM> is considered to be the IUNCOMP measure of light intensity. Here the measure of intensity includes the subscript "uncomp" because this measurement that has not yet been compensated for temperature induced variations in the signal from the photodetector. Since this measurement of light intensity is essentially the same measurement that is made in step <NUM> it is identified as the execution of step 346a in <FIG>. Then the processor, in a step <NUM>, based on the above variables determines the IA the temperature compensated measurement of light intensity. Specifically, in step <NUM> the uncompensated measure of light intensity from photodetector <NUM> is converted into the temperature compensated measurement according to the following equation: <MAT>.

This version eliminates the need to provide a temperature sensor adjacent the photodetector <NUM> in order to light intensity measurements that are compensated to account for temperature induced changes in the sensitivity of the photodetector.

It should be appreciated that step <NUM> could be performed immediately before or after step <NUM> of <FIG> is performed. Step <NUM> can likewise be performed immediately after step 346a is executed. Likewise there is no requirement that each execution of step 346a be immediately followed by the execution of the companion step <NUM>. Thus, at the end of the sterilization process each of the IUNCOMP uncompensated measurements of light intensity may be converted into the IA temperature compensated versions of these measurements. The temperature compensated measurements are then, in the plural executions of step <NUM> be used to determine concentration of the gas of interest.

It should be understood that the sterilization container with sensor module may have features different from what has been described.

For example, alternative assemblies may be employed to measure the environmental characteristics that need to be measured in order to evaluate the effectiveness of the sterilization process. Thus, when it is necessary to measure the absorption of light at different wavelengths to measure the concentration of different gases, it may be desirable to provide plural photodetectors. Each one of the plural photodetectors is sensitive to a specific one of the wavelengths of the light the absorption of which is being measured. A benefit of this version is that, by making the plural measurements simultaneously, it is possible to determine for a given moment in time the concentrations of the plural gases of interest.

In still another version, the sensor assembly used to measure the concentrations of plural gases may include a single light source and/or a single light sensitive transducer. More specifically, the light source may emit light over a range of wavelengths. This range of wavelengths it is understood includes the wavelengths of light that are absorbed by the gases for which the concentration measurements are required. Thus, the light source could emit white light, light over the full range of the wavelengths of visible light.

The single transducer could be a spectrometer or an FTIR. The output from the spectrometer or FTIR is a measure of light intensity over a range of frequencies. Based on a measurement, the processor <NUM> determines the intensity of light for the frequencies of interest. This version can, like the version with plural photodetectors, be used to determine, at a given moment in time, the concentrations of the plural gases of interest.

Likewise there is no requirement that in all versions, the light the absorption of which being measured must be reflected or when reflected be reflected on a single back-and-forth path. In some versions, the light emitter (emitters) and complementary detector (detectors) may be spaced apart from each other. The light may travel along a single line path from the emitter to the detector. In this version, the sensor module is not provided with an assembly for reflecting the light.

As depicted in <FIG>, the module may be constructed so that the light as it travels between the emitter <NUM> and detector <NUM> is reflected a number of times. In <FIG> installed in the sensor module are two parallel mirrors <NUM> and <NUM>. Mirror <NUM> is depicted as longer than mirror <NUM>. The light beam <NUM> emitted by emitter <NUM> strikes mirror <NUM> and then strikes mirror <NUM>. The light then is repeatedly reflected back and forth between mirrors <NUM> and <NUM>. After reflecting off mirror <NUM> one last time the light strikes the detector <NUM>.

In this version, the path of travel of the light is greater than the distance along the length of the mirrors <NUM> and <NUM>. This makes it possible to, in a given volume have the light travel along a path that is greater than the length of the major axis through the volume. This is advantageous because the longer the path of the light through the volume in which the gas is present, the more light will be absorbed by the gas. This makes it possible to, based on a measure the absorbed gas, provide a measure of gas concentration.

As depicted in <FIG>, in still another version, a beam of light <NUM> emitted by an emitter is applied to a collimator <NUM>. The collimator narrows the light beam. The reflector <NUM> that reflects the light to detector <NUM> is a prism like assembly with plural reflective surfaces. The light beam is reflected onto one of the surfaces, continues to transit through the reflector <NUM> before being reflected off a second surface and out of the reflector. The light beam <NUM> passes through a filter <NUM> before striking the detector <NUM>. A benefit of providing these components internal to the sensor module is that the light beam <NUM> that strikes the detector <NUM> should consist of photons that are both focused on the detector and essentially all at the wavelength the measurement of which is use for determining gas concentration.

In still other versions, the path along which the beam of light the intensity of which is measured is bent or curved with the use of concave mirrors or fiber optic cables.

If appropriate, the sensor module of the sterilization container may be provided with plural collimators <NUM> of filters <NUM>. In versions, wherein the light emitter is a coherent light source, a laser, it be possible to eliminate these components.

Likewise, it should be understood that in other versions of the sterilization case, sensors other than light intensity sensors may be used to monitor gas concentration. For example, passive components the characteristics of which vary as function of gas concentration may be employed as these transducers. Thus, resistors or capacitors, the characteristics of which may change as a function of gas concentration, may be employed as the sensors.

Similarly there is no requirement that in all versions, the sensor module must be mounted to the container lid. In alternative versions, the sensor module is mounted to the bottom, front, rear or one of side panels of the case of the container.

The number and type of sensors are understood to be a function of the potential sterilization processes to which the sterilization container can be subjected. For example, if ethylene oxide is one of the sterilizing gases to which container could be exposed, then the sensing module includes sensing components that provide signals representative of the concentration of this gas. Some versions may have plural sensors for monitoring the temperature within the container. These plural sensors are typically located so that at least one sensor is positioned in a space in which there is relatively unimpeded gas flow. The second sensor is located within a space in which structural features impede the flow of gas around the sensor. Alternatively, in terms of gravity, the sensors are spaced apart from each other so that one sensor is located above the other sensor. The signals representative of container temperature output by these signals are used by the processor to determine whether or not the container is saturated with steam.

Not all versions may have all of the above described components. For example, it may not be necessary to provide the heating elements adjacent the windows through which the light emitted as part of the gas measurement process or the mirrors that reflect this light.

In some versions, it may not be possible to provide the emitter/emitters that emit light for the gas/vapor measurement process and the complementary detectors in the same sealed housing. These versions may not include any mirrors for reflecting light.

Alternative means may be provided for outputting the data and information generated by the sensor. For example, the sensor module may be provided with a transmitter. Typically this transmitter is wireless. In some versions ,in which the transmitter is an RF transmitter, the transmitter is also able to receive signals. In this version, processor <NUM> may perform evaluations to determine whether or not the sterilization process as a whole or a particular phase (step) has been completed. If this evaluation tests true, the processor causes the transmitter to transmit this information to a complementary receiver integral with the sterilizer. The sterilizer, upon receipt of this information advances to the next step of the sterilization process or presents this information on a display.

In some versions, the module components that present information regarding the sterilization state of the instruments in the module may only be pulse on. This again is to minimize the drain of charge on the battery.

Some sterilization containers may include one or more valves. These valves open and close inlet ports into the container with which the valves are integral. In these versions, the processor, based on whether measurements indicating whether or not the container is being subjected to a sterilization process, asserts the command signals that open and close these valves. Similarly, there is no requirement that in all versions, the sensor module must be mounted to the lid. In alternative versions, the module may be mounted to one of the panels that form the container body.

Likewise, while it is believed preferred that sensor and other components of the sensor module be located inside the container, it is within the possibilities that anywhere from one to all of the components of the sensor module may be mounted to the container to be located outside of the container. In these versions, typically at least some if not all of the sensors will be disposed inside the container. Some of these versions will include components that facilitate the communication of the signals from the sensors inside the container to the components located outside of the container.

Alternative constructions of physical features may also vary from what has been described. For example, the temperature sensitive transducers <NUM>, <NUM> and <NUM> may be mounted directly to the photodetectors or LEDs the temperatures of which the transducers monitor.

Likewise it may be desirable to adjust the levels of the currents applied to the light emitters <NUM> and <NUM>. This adjustment would compensate for changes in the ability of the light emitters to emit substantially the same quantity of light over the life time of the emitters. This helps maintain the I<NUM> values of light substantially constant.

<FIG> depicted a portion of a sterilization container with features according to the appended claims. This sterilization container includes a sensor module <NUM>. The sensor module <NUM> is attached to one of the panels <NUM> of a sterilization container. Sensor module <NUM> includes a shell <NUM> that functions as the outer body of the module. The shell <NUM> is generally rectangularly shaped. Shell <NUM>, like other components exposed to sterilant, is formed from a material able to withstand the corrosive effects of the sterilant.

Feet <NUM> (two identified) project outwardly from one of the major outer surfaces of shell <NUM>. Feet <NUM> are the elements of the module <NUM> that abut the panel <NUM> to which the module is attached. Feet <NUM> are made from material that has relatively low thermal conductivity, typically at or less than <NUM> Watts/m-°K. Feet <NUM> are formed from material of low thermal conductive to minimize the extent to which there is an exchange of thermal energy between sterilization container <NUM> and sensor module <NUM>.

Shell <NUM> is formed to define three internal voids. A primary void, void <NUM>, in terms of surface area is the largest of the three voids. There are two additional voids <NUM> and <NUM> located immediately inward of one of the outer walls of the shell. A web <NUM> internal to the shell separates void <NUM> from voids <NUM> and <NUM>. Voids <NUM> and <NUM> are open to the environment in the sterilization container <NUM> through an opening <NUM> in the shell. The space in the shell above the opening <NUM> is considered to be void <NUM>. The space below opening <NUM>, void <NUM>. A T-shaped flow diverter <NUM> is located internal to the shell <NUM> immediately inward of opening <NUM>. Diverter <NUM> is the mechanical component of sensor module <NUM> that separates void <NUM> from void <NUM>.

Four bores are formed in web <NUM>. Two of the bores, bores <NUM><NUM><NUM>, ( one identified) are located on opposed sides of opening <NUM> and diverter <NUM> and are relatively close to the diverter. One bore <NUM> extends from void <NUM> to void <NUM>. The second bore <NUM> extends from void <NUM> to void <NUM>. The remaining two bores, bores <NUM>, (one identified) are also located on opposed sides of opening <NUM> and diverter <NUM>. Bores <NUM> are spaced distal to the diverter <NUM>. One bore <NUM> extends from void <NUM> to void <NUM>. The second bore <NUM> extends from void <NUM> to void <NUM>.

Module <NUM> is further formed to have an outlet port <NUM>. The outlet port <NUM> is formed in the outer wall of the shell so as to open from the lowest portion of void <NUM>. A valve <NUM> is mounted to the module <NUM> so as to extend over the outlet port <NUM>. Valve <NUM> normally closes the portal between outlet port <NUM> and the adjacent environment internal to the container <NUM>. When valve <NUM> is closed, gaseous state fluid is not able to pass through port <NUM>. Thus, it should be appreciated the sensor module is designed so that gas cannot normally flow between the space within the sterilization container and the base of void <NUM>. The valve <NUM> is set to open when liquid is in the base of void <NUM>. In the depicted version, the valve <NUM> is a float valve. In other words in the absence of valve <NUM> being open, void <NUM> is a closed end void.

A pressure sensor <NUM> (one identified) is mounted in each of the bores <NUM>. A temperature sensor <NUM>, shown symbolically, is disposed in void <NUM>. Temperature sensor <NUM> sources a signal representative of the temperature at or near the pressure sensors <NUM>. In some versions, integral with each pressure sensor <NUM> is a temperature sensor <NUM> that provides an indication of temperature of the pressure sensor <NUM>.

A temperature sensor <NUM> (one identified) is disposed in each of the bores <NUM>. Given that bores <NUM> are spaced away from opening <NUM> it should be understood that one temperature sensors <NUM> is spaced above opening <NUM> and located in void space <NUM>. The second temperature sensor is located below the opening <NUM> so as to be located in void space <NUM>. The second temperature sensor <NUM> is further understood to be located above the base of void space <NUM>. Each temperature sensor <NUM> includes a closed end sleeve <NUM> in which the actual temperature sensitive transducer is seated. (Transducer not illustrated. ) The sleeves <NUM> are positioned to be spaced away from the walls that define the perimeters of the void <NUM> and <NUM> into which the sleeves protrude.

It is understood that sensors <NUM> and <NUM> are mounted to web <NUM> in such a manner that fluids, including pressurized steam, cannot enter void <NUM>. This substantially eliminates the likelihood that gases and vapors that surround the shell and enter voids <NUM> and <NUM> can adversely affect the components disposed in void <NUM>.

The components that monitor the signals output be sensors <NUM> and <NUM> and that evaluate the measurements made by the sensors are disposed in void <NUM>. As the structures of these components are not features defined in the appended claims, they are not illustrated. It should be understood that these components include a processor similar to previously described processor <NUM>. The temperature measurements made by the one or more temperature sensors <NUM> are employed by the processor to generate pressure measurements that are compensated to adjust for changes in the temperature of the pressure sensors <NUM>.

Also disposed in void <NUM> are cells <NUM>. Cells <NUM> supply the charges required to energize both the sensor <NUM> and the components internal to the module that store and evaluate the signals representative of the container environment.

A sterilization container <NUM> that includes sensor module <NUM> is used in a manner identical to how a conventional sterilization container is used. During a sterilization process, sterilant enters voids <NUM> and <NUM> through opening <NUM>. Some sterilization processes include at least one step in which the instruments being sterilized must be in a saturated steam environment.

To determine whether or not instruments are in a saturated steam environment, the processor internal to the module <NUM> first reads the pressure as measured by one of the pressure sensors <NUM> and the temperature as indicated by the upper of the two temperature sensors <NUM>. By reference to steam data tables, these data indicate the state of the steam in void <NUM>. These data may indicate that steam is present in void <NUM>. However, this data does not indicate if the steam is in the same state throughout the whole of the container.

To make this determination, the processor evaluates whether or not the environmental temperatures as measured by both temperature sensors <NUM> are substantially equal and near a target temperature. This target temperature is the temperature of saturated steam at a given absolute pressure. Generally, this target temperature is near <NUM>. As a result of this evaluation it may be determined that the temperature of void <NUM> is less than the temperature of void <NUM>. When the gases in the sensor module <NUM> are in this state, there is high likelihood that the gas in void <NUM> includes a sizeable fraction of air. This means closed ended voids defined by the instruments in the container may still contain a sizeable fraction of air. Accordingly, should the processor determine that the temperatures in voids <NUM> and <NUM> are in this state, the processor considers the environment in the container to be one in which the instruments are not essentially surrounded by saturated steam.

Alternatively, the evaluation may indicate that the gases in voids <NUM> and <NUM> are essentially equal and near the target temperature. When the gases are in this state void <NUM> is essentially entirely filed with vaporized water vapor (saturated steam). Accordingly, the sensor module processor interprets this result as indicating that the instruments in the sterilization container are essentially completely surrounded by saturated steam.

There may be times the steam in the void <NUM> condenses. When this event occurs, the now liquid state water flows towards outlet port <NUM>. The liquid-state water valve causes the valve <NUM> to open. The liquid state water thus flows out of the void space <NUM>. This prevents the pooling of water in the sensor module.

It should be understood that sensor module <NUM> is often mounted immediately above the bottom panel of the container body <NUM>. For example less than <NUM> above the bottom panel and often <NUM> or less above this panel. This is because owing to water vapor being less dense than air, it is bottom of the container body <NUM> that is the last portion of the container to fill with saturated steam. By placing module <NUM> adjacent the bottom of the container, the signals from the module provide measurement upon which it can be determined whether or not this portion of the container has filled with steam.

An alternative sensor module <NUM> that can be mounted to a panel <NUM> (<FIG>) of a sterilization container is now described by reference to <FIG>. Sensor module <NUM> includes many of the same components of sensor module <NUM>. To reduce redundancy, these components will not be redescribed unless necessary.

Sensor module <NUM> includes a web <NUM> that is substitute for web <NUM> of sensor module <NUM>. Web <NUM> includes the previously described bores <NUM> and <NUM>, one of each identified. Web <NUM> is formed with two additional bores, bores <NUM> one identified. A first one of the bores <NUM>, extends between void <NUM> and void <NUM>. The second bore <NUM> extends between void <NUM> and void <NUM>.

An elongated, rod-like thermal mass is disposed in each bore <NUM>. A first thermal mass, mass <NUM>, protrudes into the void <NUM> associated with the bore <NUM> that opens into void <NUM>. The second thermal mass, mass <NUM>, protrudes into void <NUM> associated with the bore <NUM> that opens into void <NUM>. The opposed ends of both thermal masses <NUM> and <NUM> extends into void <NUM>. The thermal masses <NUM> and <NUM> are both formed from material that has a relatively high specific heat per unit volume. One definition of specific heat per unit volume for thermal masses <NUM> is that they have a higher specific heat per unit volume than the specific heat per unit volume of the surrounding structural features of the sensor module <NUM>. Thus if web <NUM> is formed from aluminum, thermals masses <NUM> and <NUM> may be formed from stainless steel. While not illustrated, in some versions each thermal mass <NUM> and <NUM> is encased in a tube like insulating sleeve. The sleeve extends between the inner surface of the web <NUM> that defines the bore <NUM> in which the thermal mass is seated and the mass. The sleeves are formed from material that is less thermally conductive than either the web <NUM> or the thermal masses <NUM> and <NUM>.

In the depicted version, each thermal mass <NUM> and <NUM> is formed to have a closed end bore <NUM>. The bore <NUM> extends inwardly from the end of the mass <NUM> or <NUM> seated in void <NUM>. A temperature sensor is mounted in each bore <NUM>. In <FIG>, temperature sensor <NUM> is seated in the thermal mass <NUM>. Temperature sensor <NUM> is seated in the thermal mass <NUM>.

Sensor module <NUM> is used to determine state of the steam in the sterilization container in which the module is mounted. Sensor module <NUM>, like sensor module <NUM>, is mounted to one of the vertically oriented panels of the container body <NUM> so that by reference to gravity void <NUM> is above void <NUM>.

The sensor module <NUM> operates based on the principle that saturated steam is more thermally conductive than either condensate, (liquid state water) or superheated steam at the same temperature and pressure. Superheated steam it is understood, is steam that is at a temperature greater than the vaporization pressure at the absolute pressure at which the temperature is measured. When the sterilization container starts to fill with steam, void <NUM>, being above void <NUM> fills with the seam prior to void <NUM> filling with steam. During this time period, time period A in <FIG>, owing to the saturated steam in the upper void <NUM> having a higher thermal conductivity than unsaturated or superheated steam in lower void <NUM>, the transfer of thermal energy into the topmost thermal mass <NUM> results in the temperature of this mass increasing at a relatively high rate, mathematically, dTU /dt where dTU is the change of temperature of mass <NUM> as measured by sensor <NUM> per unit of time dt. During time period A the air and unsaturated steam in lower located void <NUM> is less thermally conductive. Accordingly, during time period A, dTL/dt is less than dTU /dt. Here TL is the temperature of mass <NUM> as measured by sensor <NUM>. In <FIG> this is graphically depicted by during time period A the slope of the temperature change of mass <NUM>, represented by solid line <NUM>, is greater than the slope of the temperature change of mass <NUM>, represented by dashed line <NUM>.

Eventually the whole of the sterilization container fills with steam. This means that both module voids <NUM> and <NUM> are filed with saturated steam. When the sterilization container is in this state, the rate of heat transfer from the steam in void <NUM> to thermal mass <NUM> and from the steam in void <NUM> to thermal mass <NUM> should be substantially identical. During this time period, time period Bin <FIG>, dTL/dt should therefore substantially equal dTU /dt.

Accordingly, in this version, the processor, that receives the signals from temperature sensors <NUM> and <NUM>, continually uses these signals to determine the temperatures of the upper thermal mass <NUM> and the lower thermal mass <NUM>. The processor uses these signals to determine dTU /dt for upper void <NUM> and dTL/dt for lower void <NUM>. The processor compares the rates of dT0 /dt and dTL/dt for the same time periods. Based on this comparison, the processor determines whether or not the serialization container to which sensor module <NUM> is mounted can be considered essentially filed with saturated steam. The results of this evaluation is used as one of the inputs to determine whether or not the articles in the containers have been subjected to a validated sterilization process.

There may be a possibility that the steam in the sterilization containers enters superheated state. As mentioned above, the thermal transfer properties of superheated steam less than that of saturated steam. The processor uses the signals from the pressure sensors <NUM> to determine the vaporation (boiling) point of the water vapor based on these pressure measurements. The temperature measurements from sensors <NUM> can be used to determine if the steam is at a temperature of the boiling point. If this evaluation tests true, the processor can use this result as indication that the sterilization container, as opposed to be filled with saturated steam, is filled with superheated steam. The fact that the sterilization container may be in this state can be used as another input variable to determine whether or not the article in the container have been subjected a validated sterilization process.

Variations of this evaluation of steam state are possible. Most significantly, even in a saturated steam environment, dT/dt is a function of the current temperature. The temperature of the bottom thermal mass <NUM> may be less than that of the upper thermal mass <NUM> even when both masses are surrounded by saturated steam. This means during these time periods dTU /dt and dTL/dt may not be equal even though both masses are surrounded by saturated steam. To compensate for this fact, the processor may not compare the simultaneous values for these rates. Instead, the processor may compare these rates when the masses <NUM> and <NUM> are at the same temperature. Again, before the conditions in the sterilization container stabilize, the temperature of the lower thermal mass <NUM> is often below that upper thermal mass <NUM>. This means that the processor does not perform the dTU /dt to dTL/dt comparson until after lower thermal mass <NUM> reaches a temperature that was previously reached by the upper thermal mass <NUM>.

In some versions of this module, the exposed surfaces of the thermal masses may not be disposed within void spaces of the sensor module. Instead the thermal masses may simply form exposed faces of the sensor module. Thus, in some versions of the exposed faces of the thermal masses may even be flush with or recessed relative to the adjacent surfaces of the sensor module.

In some versions. it may also be necessary to compare one or both of dTU /dt or dTL/dt to calibrated temperature rates of change to determine whether or not the articles in the sterilization container were properly sterilized.

A second alternative sensor module <NUM> able to module steam state for incorporation into a sterilization container is now described by reference to <FIG> which is encompassed by the appended claims. Module <NUM> is based on module <NUM>. To reduce redundancy components common to both modules <NUM> and <NUM> where possible are not described again.

One difference between modules <NUM> and <NUM> is that module <NUM> does not include a diverter. Thus in this version, web <NUM> separates void <NUM> from a single void <NUM>. Opening <NUM> opens into void <NUM>. Further in this version, valve <NUM> is spaced away from the section of void <NUM> that extends top-to-bottom along the length of the module <NUM>.

Two transducers are mounted in module <NUM> so as to be located at opposed ends of void <NUM>. A first transducer, transducer <NUM> is mounted in side module <NUM> so as to be located a top end of void <NUM>. Transducer <NUM> emits a signal either the sonic or ultrasonic wavelengths. The second transducer, transducer <NUM>, is mounted inside module adjacent the bottom end of void <NUM>. Transducer <NUM> is positioned so that the energy emitted by transducer <NUM> will strike transducer <NUM>. Transducer <NUM> is a receiver that generates a variable signal as a function of the amount of energy emitted by transducer <NUM> that strikes transducer <NUM>.

This version is also used to determine the extent to which the sterilization container to which module <NUM> is attached is filled with saturated steam. To use module <NUM>, the time between when the sonic or ultrasonic energy emitted by transducer <NUM> and received by transducer <NUM> is measured. This signal is measured because the speed of sound is greater in volume filled with saturated steam in comparison to the same volume filled with less than saturated steam or superheated steam. This difference in the speeds sound means that the sound will travel faster through void <NUM> when the void is filled with steam in this state. The times of flight of these energy emissions are compared to a table of stored references times for these signals. Based on these comparisons the processor determines the extent to which the sterilization container is filled with <NUM>% saturated steam.

In some versions, in which the sensor module is provided with two thermal masses <NUM> and <NUM>, it is likewise only necessary that one of the thermal masses be contained in the closed end void space. In these versions, the thermal mass <NUM> not in the closed end void space can be located at or below the thermal mass <NUM> in the void space. In some versions of the invention the sensor module may only contain a single thermal mass. This would be the thermal mass the exposed end of which is the closed end void space.

Alternative versions of module <NUM>, <NUM> and <NUM> are possible while having features as defined in the appended claims. For example, the readings from the plural pressure sensors <NUM> should be identical. Therefore, one of the pressure sensors <NUM> can be omitted. When plural pressure sensors are provided, one sensor can serve as a check on the other sensor or be present as a back-up sensor.

Likewise, there is no requirement that in these versions, both temperature sensors <NUM> must be located in the enclosed void space. For the signals from the sensors to be used to evaluate the state of steam, at least one of the sensors needs to be located in the enclosed void space so as to be located below the opening into the void space. This is because if the contents of the sterilization container are filled with less than saturated steam, the void space will most likely be at least partially filled with gas other than saturated steam. This means that when the temperature inside the void space is compared to the temperature of the surrounding environment, the temperature in the void space will be less than that of the surrounding environment. If the sterilization container is filled with saturated steam, than the steam will have forced the other gases out of the void space and substantially have filled the void space. The temperature of the void space as measured by the sensor in the void space should be substantially equal to the reference temperature measured by the second sensor. Here, "reference temperature" is understood to be the temperature in the upper located void space or the temperature of the unenclosed environment inside the container as measured by the second sensor.

According to the appended claims, the sensor contained in the enclosed void space is, relatively to gravity, below the opening <NUM> while the temperature sensor located within the unenclosed environment inside the container is above the one inside the enclosed space.

An advantage of enclosing both sensors is that the structural components forming the sensors, the sleeves <NUM>, tend to be fragile. Enclosing both temperature sensors <NUM> reduces the likelihood that unintended contact with the sensors can result in their breakage.

In versions wherein the plural temperature sensors are enclosed in the void space, there may be plural openings into the void space. The temperature sensor <NUM> located in the enclosed void space is, relative to gravity, located below the opening into the void space.

It is further possible that three or more sensors be provided to measure container temperature in order to determine steam state. Thus with a three temperature sensor <NUM> version, two of the sensors may be located at different heights within the enclosed void space. These sensors would then provide an indication when the sterilization container is first partially filled and then, secondly, substantially filled with saturated steam.

In some versions the valve the allows the flow of liquid out of the closed end void space may be omitted. A screw may substitute for this valve. Alternatively, if the sensor module is removably mounted to the sterilization container, condensate can be cleaned out of the void space during the process of cleaning the module.

The above is directed to specific versions and embodiments. The container may have features different from what has been described.

Thus, the features of the different versions can be combined. For example, the feature of normally having the sensor module in the sleep state, periodically transitioning to a peek state and, when appropriate, transitioning to an active state, can be incorporated into each of the sensor modules. Likewise the feature of, when in the active state, only periodically measuring the characteristics of the environment inside or adjacent the sterilization container may be incorporated into each sensor module.

Similarly, there is no requirement that all features of each described version must be incorporated in any particular version. For example, in the versions wherein thermal masses <NUM> and <NUM> and temperature sensors <NUM> and <NUM> attached to these masses are mounted to the sensor module to determine the presence of saturated steam, it may not be necessary to provide the module with additional temperature sensors.

Likewise the sterilization containers may have features different than what has been described. For example, the vent holes and filter assembly may be mounted to the body of the container instead of the lid. In some versions, both the body container and the lid are provided with vent holes and filter assemblies.

It should likewise be understood that the structure of the sensors integral with the modules may vary from what has been described. Thus, it is possible that a single pressure sensor provides the signals representative of container pressure for the whole range of pressure for which this measurement is needed. It is further possible, that if there are plural pressure sensors that each pressure sensor be contained in its own chamber. In some sub-species of this version, a single sensor frame or shell may be shaped to define these individual chambers.

In still other versions, the transducer employed to generate signals representative of container temperature may not be a thermistor. In alternative versions of the invention, one or more thermocouples may perform this function. Thus, it is possible that a first transducer provides a measure of temperature over a first range of temperatures and a second transducer provides a signal representative of temperature over a second range of temperatures.

In further versions in which a component integral with the sensor module provides information regarding the effectiveness of the sterilization process, this component may not always be a selectively actuated light. The component may be a RF transmitter. In these versions, a low powered receiver is also integral with the sensor module. In response to an interrogation signal received by the receiver, the transmitter outputs data from the processor <NUM> regarding the effectiveness of the sterilization process. In these versions, the window through the container body or lid through the RF energy is transmitted may not be transparent to light. Instead, this window is formed of material that does not absorb the transmitted RF energy to a level at which it can not be effectively processed by the components both internal to and external from the container.

Likewise there is no requirement that in all versions, the sensor modules must be mounted inside the containers with which the modules are integral. In some versions sensor modules are mounted to an outer surface of the container base or lid. Ports in the structural member to which the module <NUM>, <NUM>, <NUM> or <NUM> is mounted expose the sensor module sensors to the environment internal to the container. Some if not all of the sensors may be disposed inside the container.

Claim 1:
A sterilization container, (<NUM>), said sterilization container including:
a body (<NUM>) shaped to hold surgical instruments (<NUM>) and adapted to allow steam to enter the body in order to sterilize the surgical instruments; and
a sensor module (<NUM>, <NUM>, <NUM>) mounted to the body, the sensor module including:
- a pressure sensor (<NUM>) for sensing the pressure inside the body,
- a first temperature sensor (480a, <NUM>) for sensing the temperature inside the body, -
a void space (<NUM>, <NUM>, <NUM>) configured to define a closed end and at least one opening (<NUM>) that forms a fluid communications path from an interior of the container body (<NUM>) into said void space;
- a second temperature sensor (480b, <NUM>) mounted to the module (<NUM>, <NUM>, <NUM>) so as to sense the temperature in said void space (<NUM>, <NUM>),
characterized in that
said second temperature sensor (480b, <NUM>) is, relative to gravity, located below the at least one opening (<NUM>) into said void space (<NUM>, <NUM>); and
the sensor module (<NUM>, <NUM>, <NUM>) is further constructed so that the first temperature sensor (480a, <NUM>) is, relative to gravity, located above the second temperature sensor (480b, <NUM>).