Technical Field

The present disclosure relates to apparatuses, systems, and methods for humidity sensing.

Background

Humidity sensors may be used in industrial and domestic applications for environmental control. Some humidity sensors include a polymeric sensing layer (e.g., polyimide (PI)) having a dielectric constant that changes relative to humidity.

During its use under previous approaches to humidity sensing, a humidity sensor may be exposed to cleaners and/or disinfectants containing a number of chemicals (e.g., volatile organic compounds (VOCs), ammonia, etc.) As one example, medical applications, for instance, may involve cleaning and/or disinfecting using chemicals.

These chemicals may enter the ambient air to which the sensor is exposed.

The chemicals may react with the polymeric sensing layer of the sensor thereby leading to the degradation (and/or delaminating) of the sensing layer. The rate of the degradation may increase with high levels of relative humidity. As a result, the sensor's functionality and/or accuracy may be affected. In some instances, the sensor's lifetime may be reduced.

Brief Description of the Drawings

Figure 1 illustrates a cross-sectional view of a humidity sensing apparatus in accordance with one or more embodiments of the present disclosure.

Figure 2 illustrates a humidity sensing system in accordance with one or more embodiments of the present disclosure. Figure 3 illustrates a method of making a humidity sensing apparatus in accordance with one or more embodiments of the present disclosure. Detailed Description

Apparatuses, systems, and methods for chemical resistant humidity sensing are described herein. For example, one or more embodiments include a casing, a humidity sensor encased in the casing, a cap fastened to the casing, a particulate filter between the cap and the humidity sensor, and a sorbent between the filter and the humidity sensor.

Humidity can be sensed (e.g., determined, acquired, etc.), in accordance with one or more embodiments of the present disclosure, with a reduction of (e.g., an elimination of) the harmful effects of harsh chemicals on a humidity sensor. According to the present disclosure, a humidity sensor can be encased in a protective casing filled (e.g., completely or partially filled) with a sorbent. The sorbent can serve to adsorb one or more airborne chemicals from the ambient air before they reach the humidity sensor. As a result, the sensor can be protected from the deleterious effects of the airborne chemicals.

The term "sensor" is used herein to refer to a humidity sensor and/or a relative humidity sensor. The sensor can include a polymeric sensing layer (e.g., polyimide (PI)) having a dielectric constant that changes relative to humidity, though embodiments of the present disclosure are not so limited.

The protected sensor may function for a longer period of time than an unprotected sensor (i.e., an unprotected sensor embodying previous approaches to humidity sensing). In addition, the accuracy and/or efficacy of the protected sensor may endure longer than previous approaches. Thus, maintenance and replacement costs can be reduced using one or more embodiments of the present disclosure.

The sorbent used to protect the sensor can be selected based on the identity and/or type of chemical(s) in (or likely to be in) the ambient air which the sensor is used to sense. For example, chemicals can include ammonia and/or volatile organic compounds (VOCs). A non-limiting list of VOCs can include, for example, acetone, benzene, butane, carbon tetrachloride, ethanol, formaldehyde, hexane, methyl methacrylate, naphthalene, trichloroethene, and many others.

A sorbent can be selected to adsorb one or more chemicals.

Though the singular term "sorbent" is used herein, those of ordinary skill in the art will appreciate that "sorbent" can refer to a single sorbent (i.e., a single element or compound) and/or a combination of more than one sorbent. Some sorbent combinations are manufactured and distributed as brand name products, some of which are shown in Table 1 below.

Embodiments of the present disclosure can include a removable cap (e.g., a screw-on cap). If the sorbent is saturated with one or more chemicals, for instance, or if the sorbent is to be changed, the cap can be removed to allow access to the sorbent. In some embodiments, a user may visualize that the sorbent has become saturated with one or more chemicals. For example, the sorbent can change color responsive to saturation by one or more chemicals.

The cap may include one or more openings to allow the flow of ambient air therethrough. Embodiments of the present disclosure can include a filter (e.g., a particulate filter), which may be integrated into the cap. The filter can block particulate access to the sorbent while allowing the flow of ambient air therethrough.

In the following detailed description, reference is made to the accompanying drawings that form a part hereof. The drawings show by way of illustration how one or more embodiments of the disclosure may be practiced.

These embodiments are described in sufficient detail to enable those of ordinary skill in the art to practice one or more embodiments of this disclosure. It is to be understood that other embodiments may be utilized and that process changes may be made without departing from the scope of the present disclosure. As will be appreciated, elements shown in the various

embodiments herein can be added, exchanged, combined, and/or eliminated so as to provide a number of additional embodiments of the present disclosure. The proportion and the relative scale of the elements provided in the figures are intended to illustrate the embodiments of the present disclosure, and should not be taken in a limiting sense.

The figures herein follow a numbering convention in which the first digit or digits correspond to the drawing figure number and the remaining digits identify an element or component in the drawing. Similar elements or components between different figures may be identified by the use of similar digits.

As used herein, "a" or "a number of something can refer to one or more such things. For example, "a number of pins" can refer to one or more pins. Figure 1 illustrates a cross-sectional view of a humidity sensing apparatus 100 in accordance with one or more embodiments of the present disclosure. As shown, the apparatus 100 includes a humidity sensor 104 encased in a casing 102, the casing 102 capped by a cap 106. The casing 102 can be cylindrical in shape (e.g., substantially cylindrical) and defined by a side surface 102-1 and a bottom surface 102-2, though embodiments of the present disclosure are not so limited. As an example, in some embodiments the casing can be a rectangular prism (e.g., a box). The cap 106 can be fastened (e.g., removably fastened) to the casing 102. In embodiments where the casing 102 is cylindrical, the cap 106 can be circular (e.g., substantially circular) and can be fastened (e.g., screwed on) to the casing 102 via a plurality of threads 120.

The threads 120 can be formed to precise standards such that ambient air is prevented from passing through the threads 120 to the interior of the casing 102. In other embodiments, the cap 106 can be fastened to the casing 102 by other means. For example, the cap 106 can be latched, clamped, clipped, pinned, and/or otherwise fastened (e.g., removably fastened) to the casing 102. In some embodiments, it may be desirable to allow removal of the cap from the casing without the use of additional devices. The cap 106 can include one or more surfaces defining one or more openings 1 12. Ambient air can pass through the openings 1 12 of the cap 106. Embodiments of the present disclosure do not limit the openings 1 12 to a particular quantity, size, and/or shape.

The sensor 104 can be attached to the casing 102 (e.g., an inner surface of the casing 102). For example, in the embodiment illustrated in Figure 1 , the sensor 104 is attached to the bottom surface 102-2 of the casing 102 by an adhesive 1 13.

The adhesive 1 13 can be room temperature vulcanization (RTV) adhesive (e.g., RTV silicone), for instance, though embodiments of the present disclosure are not so limited. Further, the sensor 104 can be attached to the casing 102 by other means (e.g., one or more fastener(s) allowing the sensor 104 to be attached to the casing 102).

The apparatus 100 can include a filter 108 (e.g., a particulate filter) between the cap 106 and the sensor 104. In some embodiments, the filter 108 can be integrated into, and/or attached to, the cap 106.

The filter 108 can filter out particulate matter from the ambient air such that particulate matter is prevented (e.g., substantially prevented) from passing through the filter 108. The filter can be a P100 filter, for instance, adapted to filter at least 99.97% of airborne particles. The casing can be filled (e.g., at least partially filled) with a sorbent

1 10. The sorbent 1 10 can be selected based on the identity and/or type of chemical(s) in (or likely to be in) the ambient air which the sensor 104 is used to sense.

For example, in some embodiments the sorbent 1 10 can be selected based on a molecular weight of chemical(s) in (or likely to be in) the ambient air which the sensor 104 is used to sense. In some embodiments, the sorbent can be adapted to adsorb ammonia. In other embodiments, the sorbent can be adapted to adsorb at least one VOC.

The sorbent 1 10 can be a powder, a porous resin, a

nanocrystalline and/or amorphous structure, etc. In some embodiments, the sorbent can be included in a cartridge and the cartridge can be placed into the casing. In some embodiments, the filter 108 can include a sorbent.

Table 1 includes a short list of some example sorbents along with related information. Tablel

Those of ordinary skill in the art will appreciate that particular sorbents can be selected to adsorb particular chemicals and that Table 1 is not intended to be taken in a limiting sense. For example, if the ambient air is likely to contain ammonia, titanium dioxide impregnated with zinc chloride can be used as the sorbent 1 10. Other sorbents can be used; embodiments of the present disclosure are not limited to a particular type of sorbent.

In any case, the sorbent 1 10 should not be a sorbent with a high affinity for water. That is, embodiments of the present disclosure do not include hydrophilic sorbents as the sorbent 1 10 as such sorbents would be likely to alter the humidity of the ambient air sensed by the sensor 104.

A distance 1 18 between the sensor 104 and the filter (e.g., a depth and/or amount of the sorbent) can be selected. In some embodiments, the distance 1 18 can be selected based on a type of the sorbent 1 10, an adsorption rate of the sorbent, a likely humidity level of the ambient air, a type of the chemical(s) to be adsorbed, a concentration of one or more chemicals in the ambient air, and/or a desired length of time before the sorbent is to be changed (or the apparatus 100 discarded). The sorbent 1 10, over the distance 1 18, can adsorb one or more chemicals from the ambient air such that the sensor 104 is prevented from being exposed to (e.g., contacting) the one or more chemicals. In some embodiments, the sorbent 1 10 can prevent a threshold amount of one or more chemicals from reaching the sensor 104. Ambient air (minus any chemicals adsorbed by the sorbent 1 10) can pass through one or more of the openings 1 12, then through the filter 108, then through the sorbent 1 10, and then come into contact with the sensor 104. The sensor 104 can sense a humidity of the ambient air and produce an output through one or more pins 1 14. In some embodiments, the output can be a particular voltage. For instance, the output can be a linear (e.g., near-linear) voltage output as a function of relative humidity percentage.

The output of the sensor 104 can be received by a controller and/or a computing device (discussed in connection with Figure 2) from the sensor 104 via the pins 1 14. As shown, the pins 1 14 can pass through the casing 102 (e.g., the bottom surface 102-2 of the casing 102) though one or more openings 1 16.

The openings 1 16 can be sealed such that ambient air is prevented from passing therethrough. In some embodiments, the openings 1 16 can be sealed with an adhesive, such as RTV adhesive (e.g., RTV silicone), for instance, though embodiments of the present disclosure are not so limited.

In some embodiments, material(s) used for the cap 106 and/or the casing 102 may be selected for their non-reactiveness with one or more of the chemicals in the ambient air. For example, the cap 106 and/or the casing 102 may be composed of a polymer, such as

polytetrafluoroethylene (PTFE) (Teflon), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and/or polypropylene. In some embodiments, polypropylene may be used in the presence of ammonia and Teflon, PVC, and/or PET may be used in the presence of one or more VOCs. Figure 2 illustrates a humidity sensing system 222 in accordance with one or more embodiments of the present disclosure. The system 222 can include a humidity sensing apparatus 200. The apparatus 200 can be analogous to the apparatus 100 previously described in

connection with Figure 1 , for instance, though embodiments of the present disclosure are not so limited. The apparatus 200 can be connected (e.g., wired and/or wirelessly connected) to a controller 224. As shown in the embodiment illustrated in Figure 2, the apparatus 200 can be connected to the controller 224 via a plurality of pins 214. The controller 224 can include logic. As used herein, "logic" is an alternative or additional processing resource to execute the actions and/or functions, etc., described herein, which includes hardware (e.g., various forms of transistor logic, application specific integrated circuits (ASICs), etc.), as opposed to computer executable instructions (e.g., software, firmware, etc.) stored in memory and executable by a processor.

For instance, the controller 224 can include logic to receive an output of the humidity sensor 104 and determine a humidity of the ambient air based on the output. However, in some embodiments, the controller can have memory that can be used to store data and can include functionality to transfer the data to a user or apparatus external to the controller.

Though not shown in Figure 2, in addition to, or in lieu of, the controller 224, the system 222 can include a computing device. The computing device can include a memory and a processor coupled to the memory.

In some embodiments, the processor can be a controller (e.g., a micro controller). The memory can be any type of storage medium that can be accessed by the processor to perform various examples of the present disclosure. For example, the memory can be a non-transitory computer readable medium having computer readable instructions (e.g., computer program instructions) stored thereon that are executable by the processor to determine humidity in accordance with one or more embodiments of the present disclosure. The memory can be volatile or nonvolatile memory. The memory can also be removable (e.g., portable) memory, or non-removable (e.g., internal) memory. For example, the memory can be random access memory (RAM) (e.g., dynamic random access memory (DRAM) and/or phase change random access memory (PCRAM)), read-only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM) and/or compact-disc read-only memory (CD-ROM)), flash memory, a laser disc, a digital versatile disc (DVD) or other optical disk storage, and/or a magnetic/solid state medium such as magnetic cassettes, tapes, compact memory cards (flash, secure digital), or disks, among other types of memory. The memory may be located in the computing device, though embodiments of the present disclosure are not so limited. For example, the memory can also be located internal to another computing resource (e.g., enabling computer readable instructions to be downloaded over the Internet or another wired or wireless connection). The computing device can include a user interface. A user of the computing device can interact with the computing device and/or the sensor 104 via the user interface.

For example, the user interface can provide (e.g., display and/or present) information to the user of the computing device, and/or receive information from (e.g., input by) the user of the computing device. For instance, in some embodiments, the user interface can be a graphical user interface (GUI) that can include a display (e.g., a screen) that can provide and/or receive information to and/or from the user of the computing device. The display can be, for instance, a touch-screen (e.g., the GUI can include touch-screen capabilities). As an additional example, the user interface can include a keyboard and/or mouse the user can use to input information into the computing device. Embodiments of the present disclosure, however, are not limited to particular types of user interface. Figure 3 illustrates a method 326 of making a humidity sensing apparatus in accordance with one or more embodiments of the present disclosure. The humidity sensing apparatus made using method 326 can be analogous to the humidity sensing apparatus 100 previously described in connection with Figure 1 , for instance, though embodiments of the present disclosure are not so limited.

At block 328, method 326 includes adhering a humidity sensor to an interior surface of a casing. The humidity sensor can be a relative humidity sensor, for instance. As previously discussed, the humidity sensor can be adhered to a bottom interior surface of the casing.

The casing can be a cylindrical (e.g., tubular) casing, for instance, though embodiments of the present disclosure are not so limited. One suitable adhesive for adhering the sensor to the casing is RTV silicone, though embodiments according to the present disclosure can include alternative or additional adhesives.

At block 330, method 326 includes forming at least one opening through the casing. The at least one opening can be formed by drilling and/or etching through the casing, for example. In some embodiments, the casing can be produced via a 3D printing process or any other additive technology process.

In some embodiments, the at least one opening can be formed on a same surface of the casing to which the sensor is adhered. In other embodiments, the at least one opening can be formed on a different surface of the casing to which the sensor is attached. In other embodiments, a portion of the at least one opening (e.g., one or more openings) can be formed one a first surface of the casing and another portion of the at least one opening (e.g., one or more openings) can be formed on a second surface of the casing.

At block 332, method 326 includes passing at least one pin of the humidity sensor through the at least one opening. Sensors herein are not limited to a particular number of pins. In addition, a quantity of pins passing through each of the at least one opening is not intended to be limited by embodiments described herein. In some embodiments, each pin of the sensor passes through a respective opening (e.g., each of three pins passes through a respective one of three openings).

Passing the at least one pin of the humidity sensor though the at least one opening can include modifying the at least one pin. For example, the at least one pin can be bent and/or lengthened such that it is able to be passed through the at least one opening.

At block 334, method 326 includes sealing the at least one opening having the at least one pin therethrough. The at least one opening can be sealed using RTV silicone, though embodiments of the present disclosure are not so limited. Sealing the at least one opening can include sealing the at least one opening such that ambient air is prevented from passing through the at least one opening.

At block 336, method 326 includes filling the casing at least partially with a sorbent. In some embodiments, the sorbent can be poured into the casing (e.g., as a powder). In other embodiments, the sorbent can be included in a cartridge and the cartridge can be placed into the casing.

The particular sorbent used to fill the casing (at least partially) can be selected based on the identity and/or type of chemical(s) in (or likely to be in) the ambient air which the sensor is used to sense. For example, in some embodiments the sorbent can be selected based on a molecular weight of chemical(s) in (or likely to be in) the ambient air which the sensor is used to sense. At block 338, method 326 includes fastening a cap provided with one or more openings to the casing. The cap is provided with one or more openings for ambient access to the sorbent, for instance. In some embodiments, the cap can be produced via a 3D printing process or any other additive technology process. The cap fastening can also be accomplished via these types of processes. As previously discussed, some embodiments include a threaded cap. In such embodiments, fastening the cap to the casing can include aligning the threads of the cap with corresponding threads on the casing and rotating the cap with respect to the casing until the cap is fastened to the casing.

However, embodiments of the present disclosure are not limited to particular fasteners or to particular manners of fastening the cap to the casing. In some embodiments, the cap is removably fastened to the casing such that the cap can be subsequently removed (e.g., unfastened) to change the sorbent or access the sensor, for instance.

Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art will appreciate that any arrangement calculated to achieve the same techniques can be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments of the disclosure.

It is to be understood that the above description has been made in an illustrative fashion, and not a restrictive one. Combination of the above embodiments, and other embodiments not specifically described herein will be apparent to those of skill in the art upon reviewing the above description.

The scope of the various embodiments of the disclosure includes any other applications in which the above structures and methods are used. Therefore, the scope of various embodiments of the disclosure should be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled.

In the foregoing Detailed Description, various features are grouped together in example embodiments illustrated in the figures for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the embodiments of the disclosure require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.