Patent Grant
10309726
This disclosure relates to the field of manufacturing, and more particularly, to autoclaves and associated manufacturing process that use autoclaves.
An autoclave is a device used in manufacturing of components, such as components made from composite materials. An autoclave includes a vessel where the pressure and temperature is controllable. Workpieces are placed inside the vessel, and the vessel is sealed. The vessel is then pressurized by pumping air or other gases through the vessel. The air enters the vessel through air inlets, and exits the vessel through air outlets. The temperature inside of the vessel may be controlled by the heating or cooling the air that is pumped through the vessel. The high-temperature and high-pressure capabilities of an autoclave make it useful for manufacturing processes, such as curing composite materials.
Although the pressure inside of the vessel is substantially uniform, the temperature of the workpiece being cured in the autoclave may not be uniform across its extent. This can be problematic when curing composite members, as some portions of a composite member may reach and maintain a proper cure temperature, while other portions may not. If portions of a composite member heat at different rates, the quality of the composite member may be compromised.
Embodiments herein describe a baffle that is deployable during a run cycle of an autoclave. One or more of the baffles are installed in the interior of the autoclave in a non-deployed or retracted position. During a run cycle, the baffle automatically deploys when a temperature within the autoclave reaches a target temperature. In a deployed position, the baffle alters the airflow through the autoclave, and consequently changes the heat transfer coefficient at the surface of a workpiece in the autoclave. Therefore, the local heat transfer coefficients within the autoclave can be changed at different locations during a run cycle by deploying the baffle(s).
One embodiment comprises an apparatus that includes a baffle located in an autoclave during a run cycle of the autoclave. The apparatus also includes a release mechanism that secures the baffle in a retracted position during the run cycle, and automatically releases the baffle to a deployed position during the run cycle when a temperature inside of the autoclave reaches a target temperature. In the deployed position, the baffle alters airflow within the autoclave.
In another embodiment, the baffle attaches to a location inside of the autoclave with a hinge mechanism, where the baffle is configured to pivot via the hinge mechanism from the retracted position to the deployed position.
In another embodiment, the release mechanism includes a material that melts at the target temperature to release the baffle to the deployed position.
In another embodiment, the release mechanism includes a material that softens at the target temperature, and flexes to release the baffle to the deployed position.
In another embodiment, the release mechanism includes a Shape-Memory Alloy (SMA) material that has a first shape to secure the baffle in the retracted position, and transforms to a second shape at the target temperature to release the baffle to the deployed position.
In another embodiment, the apparatus includes a spring mechanism that loads when the baffle is secured in the retracted position, and applies a return force to pivot the baffle to the deployed position when released by the release mechanism.
In another embodiment, the apparatus includes a stop device that stops rotation of the baffle at the deployed position.
In another embodiment, the apparatus includes an indicator mechanism that indicates when the baffle is released to the deployed position.
In another embodiment, the indicator mechanism includes a thermocouple wire installed in a path between the retracted position and the deployed position of the baffle. The baffle breaks a connection of the thermocouple wire when pivoting from the retracted position to the deployed position.
Another embodiment comprises an autoclave and one or more baffle elements installed within the autoclave. The baffle element includes a baffle, a hinge mechanism that attaches the baffle to a surface inside of the autoclave, and a release mechanism that secures the baffle in a retracted position during a run cycle of the autoclave. The release mechanism automatically releases the baffle to a deployed position during the run cycle when a temperature inside of the autoclave reaches a target temperature.
Another embodiment comprises a method of operating an autoclave. The method includes performing a thermal-analysis of an interior of the autoclave, selecting a location for a baffle element within the autoclave based on the thermal-analysis, and installing the baffle element at the location. The method includes selecting a target temperature for deploying a baffle of the baffle element during a run cycle of the autoclave, and securing the baffle in the retracted position with a release mechanism. The method further includes initiating the run cycle, and releasing the baffle to the deployed position with the release mechanism during the run cycle when a temperature inside of the autoclave reaches the target temperature.
In another embodiment, the method includes selecting the release mechanism that changes state at the target temperature.
In another embodiment, the method includes selecting a material for the release mechanism that melts at the target temperature to release the baffle to the deployed position.
In another embodiment, the method includes selecting a material for the release mechanism that softens at the target temperature, and flexes to release the baffle to the deployed position.
In another embodiment, the method includes selecting a Shape-Memory Alloy (SMA) material for the release mechanism that transforms shapes at the target temperature to release the baffle to the deployed position.
In another embodiment, the method includes installing an indicator mechanism that indicates when the baffle is released to the deployed position.
In another embodiment, the method includes installing a thermocouple wire in a path between the retracted position and the deployed position of the baffle, where the baffle breaks a connection of the thermocouple wire when pivoting from the retracted position to the deployed position.
Another embodiment comprises a method of controlling heat within an autoclave. The method includes initiating a run cycle of the autoclave, and deploying a device within the autoclave during the run cycle to alter the airflow within the autoclave and change the heat transfer to one or more regions of the workpiece.
The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.
Some embodiments of the present invention are now described, by way of example only, with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings.
The figures and the following description illustrate specific exemplary embodiments. It will be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles described herein and are included within the contemplated scope of the claims that follow this description. Furthermore, any examples described herein are intended to aid in understanding the principles of the disclosure, and are to be construed as being without limitation. As a result, this disclosure is not limited to the specific embodiments or examples described below, but by the claims and their equivalents.
For a typical run cycle of autoclave 100, one or more workpieces are loaded into vessel 102, and door 106 is sealed. Pressure is applied to vessel 102 by introducing air into air inlets 110, while the temperature in vessel 102 is ramped up to a hold temperature. The temperature within vessel 102 may be held at this temperature for a length of time to complete a process, such as a cure process. Although the pressure inside vessel 102 is uniform, the air speed may vary inside vessel 102. As hot air flows through vessel 102 from air inlets 110 to air outlets 112, the airflow may not have a consistent pattern throughout the volume of vessel 102. The uneven airflow leads to temperature variations across workpieces within vessel 102. The temperature variations may depend on the design of vessel 102, the shape of the workpiece(s), placement of the workpiece(s) within vessel 102, the shape of substructures within vessel 102, etc.
The following embodiments are able to compensate for the temperature variations within autoclave 100 and other types of autoclaves using one or more deployable baffle elements 150 that automatically deploy during a run cycle. As shown in
Baffle 201 is configured to transition from a retracted position to a deployed position at a certain temperature. Therefore, baffle element 150 further includes a release mechanism that is configured to hold baffle 201 in the retracted position, and to release baffle 201 to the deployed position during a run cycle at a certain temperature or temperature range, which is referred to as the “target” temperature.
In order to release baffle 201 at the target temperature, latch device 312 may include a material that melts or softens at the target temperature, such as a metal alloy that includes lead or tin, a thermoplastic, etc. When an operator of autoclave 100 determines the target temperature for baffle 201 to deploy, the operator may also select the type of material for latch device 312 that melts or softens at that target temperature. Latch device 312 will therefore secure baffle 201 in the retracted position as the temperature rises within autoclave 100 during a run cycle. When the temperature reaches the target temperature, latch device 312 will melt to release baffle 201, or will soften and flex to release baffle 201.
Latch device 312 may alternatively include a Shape-Memory Alloy (SMA) that transforms shapes at the target temperature, or a bimetal that flexes at the target temperature. SMAs are strong-lightweight alloys that can be programmed to remember different shapes at different temperatures. Examples of SMA materials include Nickel-Titanium (Ni—Ti), Nickel-Titanium-Hafnium (Ni—Ti—Hf), Copper-Aluminum-Nickel (Cu—Al—Ni), etc. SMAs display two distinct crystal structures or phases. Martensite form exists at lower temperatures, and austenite form exists at higher temperatures. When an SMA is in martensite form at lower temperatures, it can be easily formed to a desired shape. When the SMA is in austenite form at higher temperatures, it can be “trained” to transition into another shape. For example, the SMA may be bent, squeezed, twisted, or otherwise formed to have a different shape when in the austenite form. When made from SMA material, latch device 312 will therefore secure baffle 201 in the retracted position when the SMA material is in its low-temperature (martensite) shape. When the temperature reaches the target temperature, the SMA material in latch device 312 will transition from its low-temperature (martensite) shape to its high-temperature (austenite) shape and release baffle 201.
Release mechanism 310 may have other desired structures not shown so that latch device 312 releases baffle 201 at the target temperature. For example, latch device 312 may be coupled to an actuator. A controller may measure a temperature within autoclave 100 through a temperature sensor, and reposition latch device 312 through the actuator when the temperature reaches the target temperature in order to release baffle 201.
Baffle 201 may pivot from the retracted position to the deployed position due to gravity. The weight of baffle 201 may be selected so that it overcomes the force of airflow 330, and baffle 201 is able to pivot to and remain in the deployed position. Deployment of baffle 201 may also be assisted with a spring mechanism or the like.
In order to stop baffle 201 at the deployed position, baffle element 150 may include a stop mechanism that is used in conjunction with hinge mechanism 202. The stop mechanism may comprise any structure or device that stops the rotation of baffle 201 via hinge mechanism 202 at the deployed position.
An operator may not be able to see inside autoclave 100 during a run cycle to determine if or when baffle 201 deploys. Therefore, it may be advantageous to install a device in autoclave 100 that indicates when baffle 201 deploys.
The structure of indicator mechanism 702 as shown in
Multiple baffle elements 150 as described above may be installed within autoclave 100. The number and locations of the baffle elements 150 may depend on the temperature distribution within autoclave 100, and the airflow changes desired during a run cycle. The size and shape of each baffle element 150 may differ depending on the airflow changes desired in autoclave 100. Also, different baffle elements 150 may be utilized that deploy at different temperatures. For example, an operator of autoclave 100 may want one baffle element 150 to deploy at target temperature t1, another baffle element 150 to deploy at target temperature t2, and another baffle element 150 to deploy at target temperature t3, which are different temperatures. To do so, the release mechanism 310 for each baffle element 150 is configured to deploy at the different target temperatures.
An operator of autoclave 100 may use baffle element 150 in manufacturing processes, such as for curing composite materials.
Method 900 includes performing a thermal-analysis of autoclave 100 (step 902), and more particularly, a thermal-analysis of interior 104 of autoclave 100. For instance, a modeling program may be used to model the volume of autoclave 100, airflow patterns within autoclave 100, temperature variations within autoclave 100, etc. The modeling program may also be used to model the airflow with one or more workpieces loaded within autoclave 100. Because more airflow across a workpiece improves heat transfer to the workpiece, and less airflow across the workpiece decreases heat transfer to the workpiece, heat transfer from the airflow to regions of the workpiece may be identified or modeled. Different heat transfer characteristics may be more evident on larger workpieces.
Method 900 may further include selecting a location for a baffle element 150 within autoclave 100 based on the thermal-analysis (step 904). The location for baffle element 150 may be selected for altering the airflow 330 during a run cycle of autoclave 100 to change the heat transfer on one or more regions of the workpiece. For example, if the thermal-analysis indicates a faster airflow along one region of the workpiece and a slower airflow along another region, the location of baffle element 150 may be selected to change the airflow pattern with autoclave 100 so that these different regions of the workpiece are heated to similar temperatures. Baffle element 150 may be situated to deflect air from a faster-airflow area within autoclave 100 to slower-airflow areas within autoclave 100. Baffle element 150 is then installed at the selected location (step 906). The modeling program may also be used to select the location for baffle element 150, and to determine how baffle element 150 affects the airflow pattern within autoclave 100.
Method 900 further includes selecting a target temperature for deploying the baffle element 150 during a run cycle of autoclave 100 (step 908). Method 900 may further include selecting a release mechanism 310 that changes state at the target temperature (step 910). Step 910 is an optional step depending on the type of release mechanism 310 that is used. For example, the operator may select a material for release mechanism 310 that melts at the target temperature, changes shape (e.g., SMA) at the target temperature, or otherwise changes state at the target temperature. Method 900 further includes securing the baffle 201 of the baffle unit 150 in the retracted position with the release mechanism (step 912).
Steps 904-912 may be performed multiple times for multiple baffle elements 150 as desired.
With the baffle element(s) 150 installed within autoclave 100 at the desired location(s) and set in the retracted position, a run cycle for autoclave 100 may be initiated (step 914). It is assumed that workpieces are also loaded into autoclave 100 for the run cycle. The run cycle includes pressurizing autoclave 100, and ramping up the temperature within autoclave 100 to a hold temperature. When the temperature of airflow 330 proximate to or surrounding the release mechanism 310 of baffle element 150 reaches the target temperature, the baffle 201 is released and pivots from the retracted position to the deployed position (step 916). The deployment of baffle 201 changes the airflow within autoclave 100. This changes the heat transfer coefficient at various locations around workpieces within autoclave 100. By being able to change the heat transfer coefficient during a run cycle of autoclave 100, all regions of a workpiece (especially a large workpiece) are subjected to similar temperatures during the run cycle. For example, if the workpieces are composites that are being cured, all regions of the composite will be cured according to the desired cure specifications.
Deployment of a baffle element 150 during a run cycle of autoclave 100 enables control over heat within autoclave 100 on different regions of a workpiece.
The embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method 1100 as shown in
Each of the processes of method 1100 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
As shown in
Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method 1100. For example, components or subassemblies corresponding to production process 1108 may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft 1200 is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages 1108 and 1110, for example, by substantially expediting assembly of or reducing the cost of aircraft 1200. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while aircraft 1200 is in service, for example and without limitation, to maintenance and service 1116.
Any of the various elements shown in the figures or described herein may be implemented as hardware, software, firmware, or some combination of these. For example, an element may be implemented as dedicated hardware. Dedicated hardware elements may be referred to as “processors”, “controllers”, or some similar terminology. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, a network processor, application specific integrated circuit (ASIC) or other circuitry, field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), non-volatile storage, logic, or some other physical hardware component or module.
Also, an element may be implemented as instructions executable by a processor or a computer to perform the functions of the element. Some examples of instructions are software, program code, and firmware. The instructions are operational when executed by the processor to direct the processor to perform the functions of the element. The instructions may be stored on storage devices that are readable by the processor. Some examples of the storage devices are digital or solid-state memories, magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media.
Although specific embodiments were described herein, the scope is not limited to those specific embodiments. Rather, the scope is defined by the following claims and any equivalents thereof.
| Number | Name | Date | Kind |
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| 4974663 | Nakaji | Dec 1990 | A |
| 5203392 | Shea | Apr 1993 | A |
| Number | Date | Country |
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| 2471593 | Jul 2012 | EP |
| 2014179041 | Nov 2014 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20170089641 A1 | Mar 2017 | US |
