This application claims priority to U.S. Provisional Patent Application No. 63/268,345 filed on Feb. 22, 2022, the contents of which are incorporated herein by reference in their entirety.
The following generally relates to sensing probes such as fiber optic temperature sensing probes used to measure the temperature of a surface, and more particularly to adjustable sensing probes.
Fiber optic temperature sensors, such as temperature probes, normally include optical fiber(s) which can deliver light to a sensing material (e.g., phosphor). The light illuminates the phosphor which, in turn, luminesces. The temperature of the phosphor can be determined by observing the changes in certain characteristics of the emitted light. Differences in temperature between the phosphor and the surface to be measured (i.e., the target surface) can create difficulties in calibrating the sensor to obtain accurate measurements.
Generally, a fiber optic temperature probe includes a base and a single tube extending therefrom within which an optical fiber is positioned. A sensing tip including the sensing material is attached to an end of the tube to contact the target surface. The tube is intended to provide the probe with mechanical strength and resistance to environmental conditions, while ideally reducing heat loss from the tip to maintain the sensing material as close to the temperature of the target surface as possible. To facilitate processes such as dry etching, in which materials are etched with corrosive chemicals under high temperature, the tube should be resistant to high temperatures and corrosion in addition to having the above qualities, making material selection challenging.
Sensing tips are typically rigidly aligned with their target surface and thus there is often a small angle preventing flush contact between the surfaces, particularly when a smooth, solid surface is being measured. Poor contact between the target surface and the tip of the sensor can reduce the rate of heat transfer between the target surface and the tip, thereby slowing temperature measurements. Poor contact may also introduce additional thermal resistance, resulting in an offset between the measured and actual temperature.
Temperature probe sensing tips may also be rigidly fixed to the tube using a bonding or mechanical structure. These configurations are known to create undesirable, and potentially problematic stresses on the components during both installation and use of the probe. Moreover, some applications include relatively small areas in which to install the probe, which can create difficulties during installation.
In one aspect, a fiber optic temperature sensing probe is described. The probe includes a probe shaft comprising a first portion comprising a first projection, and a cavity for having a fiber optic cable positioned therein. The probe includes a ferrule comprising a second projection, the second projecting cooperating with the first projection to prevent the ferrule and probe shaft from uncoupling from an assembled configuration. The probe includes a biasing member connected to, and encouraging displacement between, the ferrule and the first portion, The probe includes a sensing element positioned at a distal end of the ferrule and proximate to a surface to be measured, the sensing element configured to interact with light received from the fiber optic cable to measure a temperature of the surface to be measured.
In example embodiments, the sensing element snap-in fits with, or includes threading complementary to threading proximate to, an opening of the ferrule. In example embodiments, the opening has a chamfered lip to facilitate the snap-in fit of the sensing element.
In example embodiments, the second projection includes a chamfered lip to generate a snap-in fit with the first projection.
In example embodiments, the ferrule includes a first chamber extending from the sensing element to a wider second chamber thereby defining a shoulder, the shoulder restricting movement of the first projection towards the sensing element. In example embodiments, a minimum distance between the sensing element and the probe shaft in an optical axis is defined by the shoulder.
In example embodiments, the second projection includes an inner chamfer to interface with a rear shoulder of the first portion to impede disassembly of the probe shaft and the ferrule.
In example embodiments, the ferrule or the sensing element is coupled to the surface to be measured.
In example embodiments, a base portion of the probe shaft engages a seal to form a vacuum seal between the probe shaft and the surface to be measured. In example embodiments, the base portion of the probe shaft is separable from the first portion.
In example embodiments, the ferrule includes at least a first ferrule part and a second ferrule part different from the first ferrule part. In example embodiments, the first ferrule part can rotate with respect to the second ferrule part, or rotate with respect to the probe shaft.
In example embodiments, the probe further includes a seal, the seal interacting with a wall and the probe shaft to generate a vacuum seal.
In example embodiments, the sensing element includes one or more of diamond, aluminum, copper, gold, nickel or nickel alloy, aluminum nitride, and silicon carbide.
In example embodiments, a contact area between the sensing element and the ferrule is less than 2 mm2, or less than 1 mm2, or less than 0.5 mm2, or less than 0.25 mm2.
In example embodiments, the sensing element has a thermal conductivity greater than 20 W/m−1K, or greater than 150 W m−1/K, or greater than 225 W m−1/K, or greater than 300 W m−1/K.
In another aspect a fiber optic temperature sensing system is disclosed. The system includes a probe body. The probe body includes a base portion, a body extending from the base portion and terminating at a head portion, a passage through the base portion and the probe body, and a fiber optic cable within the passage. The system includes at least one ferrule including a first opening at a first end, the first opening providing a snap-in or threaded-in fit with the head portion. The system includes a biasing member positioned to apply force to the at least one ferrule towards a surface to be measured, and a sensing element positioned at a second end of the at least one ferrule, opposite the first end, the sensing element comprising a sensing material for interacting with light from the fiber optic cable positioned in the passage.
In example embodiments, wherein the sensing material is coupled to the surface to be measured.
In another aspect, a method of assembling a fiber optic temperature sensing probe is disclosed. The method includes providing a first part and a second part of a probe shaft, the first and second parts of the probe shaft including passages configured to receive fiber optic cables. The method includes providing a first fiber optic cable and a second fiber optic cable, and inserting the first fiber optic cable into the first part of the probe shaft. The method includes inserting the second fiber optic cable into the second part of the probe shaft, and providing a block. The method includes providing a cap, connecting the first part of the probe shaft to the block, and connecting the second part of the probe shaft within the cap. The method includes assembling the block to the cap, optically aligning the respective fiber optic cables of the first part of the probe shaft and the second part of the probe shaft.
In example embodiments, connecting the first part of the probe shaft to the block includes sealing the first part of the probe shaft to the block with a seal. In example embodiments, the first part of the probe shaft comprises a ferrule, the ferrule comprises at least a first ferrule part and a second ferrule part different from the first ferrule part and the first ferrule part is configured to rotate with respect to the second ferrule part, or rotate with respect to the probe shaft. In example embodiments, the first part of the probe shaft comprises a ferrule, the ferrule comprises at least a first ferrule part and a second ferrule part different from the first ferrule part and the first ferrule part is configured to rotate with respect to the first part of the probe shaft.
Embodiments will now be described with reference to the appended drawings wherein:
Turning now to the figures,
In the shown example, the temperature probe 12A is fitted into a cap block 18 by way of an O-ring 20. Other sealing mechanisms may be contemplated. A transition block 22 is secured to the cap block 18 and together the cap and transition blocks 18, 22 define a passage 24 through which a cable 26 (e.g., a fiber optic cable, and hereinafter referred to as optic cable 26 for ease of reference) can pass It can be appreciated that the delineation between the cap and transition blocks 18, and 22, respectively, in
It can be appreciated that in an environment having a sharp bend in the optic cable 26, a bundle of thin optical fibers can be used to permit bending. In various example embodiments, at least a portion of optic cable 26 may include one or more plastic fibers or one or more glass fibers or one or more silica fibers. For example, the individual fibers in such a bundle can slide relative to each other to accommodate bends more readily, and with reduced stress. In various example embodiments, the radius of curvature of the flexible portion of optic cable 26 can be less than about 50 mm, or less than about 25 mm, or less than about 15 mm, or less than about 5 mm. It can also be appreciated that the sensing environment 10 shown in
Upper and lower portions 13C and 13D can be separable and resealable (e.g., via mechanical couplings such as complementary fasteners, etc.), and the optic cable 26 can relatedly be separated into an upper cable portion 26A and a lower cable portion 26B. For example, the upper and lower portions 13C and 13D can include mating mechanical features, such as complementary threading, which permit the portions to engage and be assembled and separated. In other embodiments, upper and lower portions 13C and 13D may be configured to be positioned within cap and transition blocks 16 and 18, respectively such that they are not mechanically coupled but that the optical axes of cable portions 26A and 26B are colinear.
As alluded to above, one or more alignment features can be used to assemble the upper and lower portions 13C and 13D. The alignment features can enable (re) sealing and separation of portions 13C and 13D, and also (or in the alternative) facilitate optically aligning the ends of cable portions 26A and 26B. The alignment feature can be on either or both of portions 13C, and 13D. In respect of alignment, in various example embodiments, the optical co-linearity (the distance between the respective optical axes of the cable portions 26A, 26B, where an optical axis is defined by a direction of light exiting or entering the end of the optical fiber portion) between cable portions 26A, 26B may be less than 0.5 mm, or less than 0.25 mm or less than 0.1 mm, or less than 0.05 mm. In various example embodiments, the alignment feature(s) is one or more fastener(s) 29 that interacts with portions 13C, and/or 13D, and at least in part fixes the probe 12B with respect to one of the support block 16 or cap and transition blocks 18, 22, respectively. Example fasteners 29 can include adhesives, mechanical fasteners, etc.
The portions 13C and 13D can also be sealed with respect to the support block 16 or cap and transition block 18, 22. For example, a seal may be formed between upper portion 13C and support block 16 using an O-ring. In example embodiments, the alignment features at least in part responsible for sealing the portions to one of the blocks. In various embodiments such a seal may be a vacuum seal, for example to prevent a leak from within passage 17 to the exterior ambient.
For clarity, in an assembled configuration, the portions 13C and 13D allow light to pass bidirectionally between the cable portions 26A, 26B. The assembled configuration can include the cable portions 26A and 26B contacting one another, or the cable portions 26A and 26B being separated by a gap 27 that enables the cable portions 26A and 26B to pass light bidirectionally between themselves.
In example embodiments, the probe 12B can be assembled in a variety of different manners. For example, upper portion 13C can be attached to support block 16. This may permit installation of the lower portion 13D in cap and transition blocks 18 and 22, and separate installation of portion 13C in support block 16, such that support block 16 and cap and transition blocks 18, and 22 may be physically separated and mated without requiring additional support of either portions 13C and 13D and while providing optical alignment of cable portions 26A, 26B.
Temperature probes disclosed herein can be configured for ambient pressures less than atmospheric pressure.
Temperature probe 12C includes a seal 31 between optic cable 26 and lower portion 13B. For example, the seal 31 can be a metal seal (e.g., a metal seal enclosing opposing ends of a cavity), an adhesive (e.g., an epoxy or ceramic adhesive), a radial seal, or other seal, such as O-ring(s) on an end(s) of a gap between the optic cable 26 and the lower portion 13B. In at least some example embodiments, the assembled configuration of probe 12C includes a seal (not shown) between the lower portion 13B and cap block 18, similar to the seal 31 between the optic cable 26 and the lower portion 13B. In example embodiments, the seal 31 includes, or generates, a vacuum sealed cavity. Various methods of realizing the seal 31 are contemplated. It is understood that the term seal does not require a perfect seal. For example, the seal 31 may have a leak rate less than about 1E-8 torr-I/sec, or less than about 1E-9 torr-I/sec or less than about 1E-10 torr-I/sec.
A probe according to the disclosed embodiments can be sealed in cooperation with various features of the blocks 16, 18 and 22. For example,
It is understood that the probes 12A, 12B, 12C, and 12D, depicted in
Different sizing of probes and cables is contemplated. For example, referring to
A ferrule 42 or other tubular component is assembled with, or attached to, or connected with the upper portion 13A (e.g., at a distal end of the shaft 40). The ferrule 42 can be composed of various materials depending on the application. For example, the ferrule 42 can include a high temperature plastic, a ferrous or non-ferrous metal, or a ceramic for particularly high temperature applications. The ferrule 42 provides an opposing surface against which the spring 46 can engage so as to bias (or displace) the ferrule 42 away from the base portion 48 to force a sensing element 44 against a surface, such as the surface 15 of the measured object 14 as shown in
Referring now to
The ferrule 42 can be a tubular member or otherwise include a cavity or passage therethrough. In this example, the distal opening 56 leads to a first chamber 58. The first chamber 58 transitions to a wider second chamber 60 to define a shoulder 62. The second chamber 60 permits a head portion 66 of the probe shaft 40 to slide axially within the ferrule 42.
During assembly, the head portion 66 of the probe shaft 40 is inserted into the second chamber 60 by inserting outwardly facing projection(s) 73 (hereinafter referred to in the singular, for ease of reference) of the head portion 66 into an opening in the ferrule 42, the opening being defined at least in part by inwardly facing projection(s) 64A (hereinafter referred to in the singular, for ease of reference) in opposition to projection 73 to enable a snap-in fit. It is understood that the term projection can be defined at least in part by a direction radial to the optical path of the optic cable 26.
The projection 64A can include a chamfered inner surface 64B to facilitate the insertion of the projection 73 into the chamber 60. A chamfered extension 68 protrudes from the head portion 66 and is relatively narrower than the projection 73 to facilitate alignment of the probe shaft 40 and the opening defined by the chamfered surface 64B during assembly.
As alluded to above, the head portion 66 can include the projection 73 for impeding decoupling, or disassembly, of the probe shaft 40 from the ferrule 42. The projection 73 can include a polygonal outer surface to provide a snap-in feature to facilitate assembly of the sensing probe 12. For example, as shown in
The assembly of the ferrule 42 and the probe shaft 40 facilitates transmitting light towards the sensing element 44. In various example embodiments, sensing element 44 may include or consist of a material having a relatively high thermal conductivity, for example diamond, aluminum, copper, gold, nickel or nickel alloy, aluminum nitride, silicon carbide or the like. In various example embodiments, sensing element 44 may have a thermal conductivity, greater than about 20 W/m−1K (e.g., using alumina), greater than about 150 W m−1/K, or greater than about 225 W m−1/K or greater than about 300 W m−1/K.
In various example embodiments, ferrule 42 and sensing element 44 may be configured to reduce the thermal conductivity between sensing element 44 and ferrule 42. For example, the contact area between sensing element 44 and ferrule 42 can be reduced, or an insulator (e.g., low-conductivity coating) can be applied to the surface of one or both materials to increase the thermal resistance between sensing element 44 and ferrule 42. In various example embodiments, the contact area between sensing element 44 and ferrule 42 may be less than about 2 mm2, or less than about 1 mm2, or less than about 0.5 mm2, or less than about 0.25 mm2.
In various example embodiments, ferrule 42 may include or be composed of glass, aluminum oxide, aluminum, copper, aluminum nitride, silicon carbide, zirconia, polyetheretherketone (PEEK), polyimide, polyamide-imide (PAI), polybenzimidazole (PBI), Ultem, or the like.
As seen in
As discussed above, the configuration of the sensing probes 12 as shown in
In yet another configuration shown in
Referring now to
In various example embodiments, the rotating ferrule part 42B and the sliding ferrule part 42A have at least one snap or thread or other fastening feature that allows for installation to the main body 47 and then constrains the ferrule parts 42A, 42B to the main body 47 after installation.
An adjustable ferrule, such as ferrule 42 shown in
For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the examples described herein. However, it will be understood by those of ordinary skill in the art that the examples described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the examples described herein. Also, the description is not to be considered as limiting the scope of the examples described herein.
It will be appreciated that the examples and corresponding diagrams used herein are for illustrative purposes only. Different configurations and terminology can be used without departing from the principles expressed herein. For instance, components and modules can be added, deleted, modified, or arranged with differing connections without departing from these principles.
Although the above principles have been described with reference to certain specific examples, various modifications thereof will be apparent to those skilled in the art as outlined in the appended claims.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/CA2023/050222 | 2/22/2023 | WO |
Number | Date | Country | |
---|---|---|---|
63268345 | Feb 2022 | US |