System and method for calibrating volatile organic compound detection instruments

Abstract

The present application relates to systems and methods for calibrating volatile organic compound detection instruments. Embodiments generally relate to systems and methods for calibrating gas detectors. Some embodiments may include a gas detector comprising one or more sensing elements configured to detect volatile organic compounds (VOCs), and a probe configured to provide an air flow into the gas detector, wherein the probe comprises: a housing configured to be connected to the body of the gas detector and configured to accommodate a calibration tube during calibration of the gas detector; a cap configured to be connected to the housing and configured to be sleeved on and cover the calibration tube; and one or more inlets, wherein when the calibration tube is inserted into the probe, air flows through the calibration tube. In some embodiments of the gas detector, the calibration tube inserted into the probe contains an activated carbon fiber (ACF) filter material.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a divisional application of an invention patent application with an application date of June 15, 2017, application number 201710450789.4, and titled “System and method for calibrating a volatile organic compound detection instrument”. This application claims priority to U.S. patent application serial number 15 / 184,388 filed by Shao Chunyu et al. on June 16, 2016 and titled “System and method for calibrating a volatile organic compound detection instrument”, which is incorporated into this application by reference as if it were fully reproduced.

[0003] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0004] not applicable

[0005] Reference to Microfilm Appendix

[0006] not applicable Technical Field

[0007] The present application relates to systems and methods for calibrating volatile organic compound detection instruments. Background Art

[0008] Gas detectors may be carried by workers and / or placed throughout the workplace and may detect gases in the environment. Gas detectors may be configured to alert users and / or supervisors when hazardous gases or gas levels are detected. To ensure that the gas detectors are functioning properly, the detectors may be calibrated (or zeroed) periodically. Some calibration methods may include providing purified or filtered air to the gas detectors and calibrating the resulting readings to a zero reference point. Summary of the invention

[0009] The present invention includes a gas detector, a method for completing a calibration process for a gas detector, and a method for preparing a calibration tube for a gas detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a more complete understanding of the present disclosure, reference is now made to the following brief description taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0011] Figure 1 A calibration tube according to one embodiment of the present disclosure is shown;

[0012] Figure 2A-2B shows a calibration tube and packaging according to one embodiment of the present disclosure;

[0013] Figure 3 A method according to an embodiment of the present disclosure is shown;

[0014] Figure 4 A gas detector according to one embodiment of the present disclosure is shown;

[0015] Figure 5 A probe according to one embodiment of the present disclosure is shown; and

[0016] Figure 6 A device connected to a gas detector according to an embodiment of the present disclosure is shown. Figure 5 probe. DETAILED DESCRIPTION

[0017] It should first be understood that although the following describes illustrative implementations of one or more embodiments, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or not yet available. The disclosure should not be limited in any way to the illustrative implementations, drawings, and techniques described below, but may be modified within the scope of the appended claims and their full scope of equivalents.

[0018] The following brief definitions of terms should apply throughout this application:

[0019] The terms "includes / comprising / containing" mean including but not limited to, and should be interpreted in the manner typically used in a patent context;

[0020] The expression "in one embodiment," "according to one embodiment," and the like generally means that a particular feature, structure, or characteristic following the expression may be included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention (importantly, these expressions are not necessarily referring to the same embodiment);

[0021] If the specification describes something as "exemplary" or "example", it should be understood to refer to non-exclusive examples;

[0022] The terms "about" or "approximately" and the like, when used in conjunction with a numerical value, can mean that specific numerical value, or can mean a range around that specific numerical value, as understood by those skilled in the art; and

[0023] If the specification states that a component or feature "may", "can", "may", "should", "would", "preferably", "perhaps", "typically", "optionally", "for example", "usually", or "might" (or other similar language) be included or have a property, that particular component or feature is not required to be included or have that property. These components or features may optionally be included in some embodiments, or they may be excluded.

[0024] Embodiments of the present disclosure include systems and methods for calibrating gas detectors. Some gas detectors can be configured to detect volatile organic compounds (VOCs). Indoor and outdoor VOCs are harmful to human health, and increased VOC concentrations in production environments can reduce product quality and yield. In order to ensure safety and efficiency, it is important to quickly and accurately detect trace total VOC (TVOC) concentration levels (e.g., expressed in parts per million (ppm) and / or parts per billion (ppb)). Photoionization detectors (PIDs) (which may also be more generally referred to as "gas detectors") can typically be used for TVOC detection and can be characterized by high sensitivity (achieving ppb level resolution), fast response time (generally seconds), and a wide range of detectable substances (most VOCs can be detected by PIDs). However, there are some problems with current PID rapid detection. Because of the zero drift trend in the sensor, PIDs require regular zero calibration. Optional methods for zero calibration include using cylinder clean air and / or using filters, but both solutions have disadvantages. When using cartridges of clean air, preparing and storing very pure air can be cumbersome and it can be inconvenient and costly.

[0025] When a filter is used during calibration, activated carbon can be used as an adsorbent to prepare a VOC zeroing tube. The filter purifies the ambient air for zero calibration and provides a zero standard, and can be low-cost and easy to use. However, a typical calibration tube with an activated carbon filter not only removes VOCs from the ambient air, but also removes water vapor. This causes the humidity of the calibration gas to be different from the humidity of the sample gas, which may affect the accuracy of the PID reading. For some rapid detection methods, such as PID, water vapor will affect the response. Therefore, the humidity difference between the filtered calibration gas and the sample gas will cause a reading deviation.

[0026] The disclosed embodiments may include systems and methods for humidifying filter materials in calibration tubes used by PIDs. The calibration filter material may be pre-treated to maintain the humidity level of the surrounding air. The absorbent material used for the calibration tube may include a porous material with a large specific surface area, and the material may not be strongly polar or absolutely non-polar (wherein strongly polar materials can absorb too much water from the filtered gas, and non-polar materials cannot absorb polar VOCs). In addition, the material may be stable in nature, configured to quickly absorb VOC gases and not release the absorbed VOCs.

[0027] In some embodiments of the calibration tube, the filter material may include activated carbon fiber (ACF), which may have high adsorption efficiency and fast humidity equilibrium speed compared to granular activated carbon due to its unique mesh fabric structure and micropores. The ACF is designed to quickly produce relatively pure gas through special pretreatment methods described herein. Embodiments of the calibration tube may include activated carbon fiber as the adsorbent material, wherein the ACF may be pretreated to humidify the adsorbent.

[0028] In some embodiments, the humidity of the gas entering the PID can be maintained at about 50% relative humidity (RH) by the calibration tube. In other embodiments, the humidity can be maintained at any point between about 10-90% RH by the calibration tube, depending on the purpose and application of the calibration tube.

[0029] See now Figure 1 , shows an exemplary embodiment of a calibration tube 100. The calibration tube 100 may include a glass shell 102, wherein a portion of the glass shell 102 may be broken before the tube 100 is used. In one embodiment, the calibration tube 100 may include a filter material 104, wherein the calibration tube 100 may be configured to filter ambient air to produce a zero standard for calibrating a gas detector. In some embodiments, the filter material 104 may include ACF (as described above). In some embodiments of the calibration tube 100, the ACF filter material 104 may be pretreated so that the filter material can maintain a humidity level greater than zero and close to the ambient humidity level. The calibration tube 100 may include a first end 106 and a second end 108. The ends 106 and 108 of the calibration tube may be broken before the tube is used to allow air to flow into the calibration tube 100 and then into the gas detector (or PID) to calibrate the gas detector.

[0030] Figure 2A-2BA method of breaking a portion of the calibration tube 100 (e.g., one or more of the ends 106 and 108) is shown. The calibration tube 100 can be packaged with other tubes in a packaging box 200, wherein the tubes can be delivered to the user in these boxes 200. In one embodiment, the box 200 can include a "tube end breaker" 202 located on the exterior of the box 200. The tube end breaker 202 can include a metal ring, a hole, or other similar material configured to break the glass material of the tube 100. The tube 100 can be inserted into the tube end breaker 202 by the user and twisted, turned and / or bent by the user (e.g., in the direction indicated by arrow 210). The first end 106 of the tube 100 inserted into the tube end breaker 202 can be broken, allowing air to flow into and / or out of the calibration tube 100. Figure 2B A close up view of the tube end breaker 202 is shown. In some embodiments, this method can be used to break both ends 106 and 108 of the tube 100 before using the calibration tube in a gas detector.

[0031] See also Figure 3 , a method 300 for assembling a calibration tube (described above) is shown. In step 302, a pre-treated saturated solution of sodium bromide (NaBr) can be prepared. In some embodiments, the NaBr solution can be prepared as a slushy mixture of distilled water and chemically pure salt. In step 304, the NaBr solution can be encapsulated in a sealed clean glass chamber, keeping the surface area of ​​the solution as large as possible. In step 306, the ACF can be desorbed in an oven at about 160°C and kept heated at this temperature for about 1.5 hours. In step 308, the heated ACF can be transferred to a glass chamber containing the NaBr solution, wherein the glass chamber can be sealed. The ACF and NaBr solution mixture can be allowed to equilibrate humidity for about 40-48 hours. In some embodiments, the ACF and NaBr solution mixture can be allowed to equilibrate for at least 24 hours. Then, in step 310, the ACF that has been pre-treated with the NaBr solution can be placed in a glass calibration tube, which can be immediately sealed in step 312.

[0032] In order to complete the calibration of a gas detector (e.g., a PID) using a calibration tube, both ends of the glass calibration tube can be broken (as described above), and the calibration tube can be inserted into the air flow entering the gas detector. In some embodiments, the gas detector may include a probe that provides an air flow to the sensor element of the gas detector. Typically, an adapter can be used to connect the calibration tube to the probe so that the air entering the probe first passes through the calibration tube. However, the process of connecting the tube can be complicated, requiring multiple separate components, and one end of the broken glass tube is exposed, creating the possibility of accidentally cutting the user's hand when completing the calibration.

[0033] Embodiments of the present disclosure include a probe structure that allows for an efficient and safer calibration process using a glass calibration tube.

[0034] Figure 4 An exemplary embodiment of a gas detector 600 is shown, wherein the gas detector 600 includes a probe portion 400. During normal use, gas sensed by the gas detector 600 may enter the gas detector 600 through the probe 400. In the illustrated embodiment, the probe 400 may include an elongated thin member extending from the body of the gas detector 600. Typically, to calibrate the gas detector 600, a calibration tube (such as the calibration tube 100 described above) may be connected to the probe 400 in some manner so that the gas sensed by the gas detector 600 is filtered by the calibration tube and / or is only received from the calibration tube.

[0035] Figure 5 An exemplary embodiment of a probe 400 is shown, wherein the probe 400 is configured to be connected to a gas detector (e.g., the gas detector 600 described above). The probe 400 may include a housing 402 and a cap 404, wherein the housing 402 may be configured to be connected to a gas detector, and the cap 404 may be configured to be threadedly mounted to and threadedly disengaged from the housing 402 via threads 403 and 405. In some embodiments, the cap 404 and the housing 402 may be connected by other connection means, such as a clip, an adhesive, a snap mechanism, and the like. The connection between the housing 402 and the cap 404 may allow the cap 404 to be simply and efficiently removed from the housing 402 and simply and efficiently reconnected to the housing 402. In some embodiments, the housing 402 and / or the cap 404 may include grooves 414 and 416 (or other gripping features) to provide a user with a secure gripping surface.

[0036] The probe 400 may include an inlet 411 near the top of the probe 400. In some embodiments, the probe 400 may include a second inlet 412 and 410 located on at least one of the housing 402 and / or the cap 404, configured to allow gas to enter the probe 400, particularly if something blocks the top inlet 411 of the probe 400. In some embodiments, the housing 402 may include the inlet 410, and the cap 404 may include the inlet 412. In some embodiments, only the cap 404 may include the inlet 412. In some embodiments of the probe 400, the housing 402 may be connected to a gas detector, and the probe 400 may include an O-ring 408 and / or a support block 406 located at the connection with the gas detector. In some embodiments, the support block 406 may include a PTFE material. In some embodiments, the O-ring 408 may be configured to seal the end of a calibration tube inserted into the housing 402.

[0037] Figure 6 Another view of the probe 400 connected to the gas detector 600 via the connection point 602 is shown. Figure 6 In the embodiment shown in FIG. 1 , the calibration tube 500 (similar to Figure 1 400) can be inserted directly into the housing 402 of the probe 400. In some embodiments, the end (or tip) 508 of the calibration tube 500 can be broken before the calibration tube 500 is inserted into the probe 400 so that the air flow entering the gas detector 600 can pass through the calibration tube 500. To protect the probe 400, and to protect the user from the broken glass end 508 of the tube, a cap 404 can be connected to the housing 402 over the calibration tube 500, covering the tube 500. Then, the calibration of the gas detector 600 can be completed, and the calibration tube 500 can be securely and safely contained within the probe 400. In some embodiments, the calibration tube 500 can contain a filter material 504 (similar to the filter material 104 described above).

[0038] When calibration is complete, the calibration tube 500 can be removed from the probe, the cap 404 can be reattached to the housing 402, and normal detection can be performed by the gas detector 600. In an alternative embodiment, normal detection by the gas detector 600 can be performed only when the housing 402 is connected to the gas detector 600. In another embodiment, the probe 400 can include a "calibration" cap used during calibration and a "detection" cap used during normal detection, which provide different functions to the probe 400 depending on the application.

[0039] Some embodiments of the present disclosure may include a gas detector comprising one or more sensing elements configured to detect volatile organic compounds (VOCs) and a probe configured to provide an air flow into the gas detector, wherein the probe comprises: a housing configured to be connected to a body of the gas detector and configured to accommodate a calibration tube during calibration of the gas detector; a cap configured to be connected to the housing and configured to be fitted over and cover the calibration tube; and one or more inlets, wherein air flows through the calibration tube when the calibration tube is inserted into the probe.

[0040] In one embodiment of the gas detector, the calibration tube inserted into the probe comprises an activated carbon fiber (ACF) filter material. In one embodiment of the gas detector, the calibration tube inserted into the probe comprises an ACF filter material that has been pretreated with a sodium bromide (NaBr) solution. In one embodiment of the gas detector, the calibration tube inserted into the probe comprises a broken glass end to allow air to flow into and out of the calibration tube. In one embodiment of the gas detector, the probe further comprises a thread between the housing and the cap. In one embodiment of the gas detector, the probe further comprises a clamping element on the exterior of at least one of the housing and the cap. In one embodiment of the gas detector, the probe further comprises an O-ring configured to seal with one end of the calibration tube when the calibration tube is inserted into the housing. In one embodiment of the gas detector, the probe further comprises an air inlet on the housing. In one embodiment of the gas detector, the probe further comprises an air inlet on the cap. In one embodiment of the gas detector, the probe further comprises a support block configured to seal the probe to the gas detector.

[0041] Some embodiments of the present disclosure may include a method for completing a calibration process for a gas detector, comprising providing a gas detector comprising a probe, wherein the probe comprises a housing configured to be connected to a body of the gas detector and configured to accommodate a calibration tube during calibration of the gas detector; a cap configured to be connected to the housing and configured to fit over and cover the calibration tube; and one or more inlets, wherein air flows through the calibration tube when the calibration tube is inserted into the probe; breaking a portion of the calibration tube to allow air to flow through the calibration tube; inserting the calibration tube into the housing of the probe; connecting the cap of the probe to the housing, wherein the cap covers the calibration tube; completing calibration of the gas detector during insertion of the calibration tube into the probe; removing the calibration tube from the probe; and receiving a gas reading by the gas detector.

[0042] In one embodiment of the method, the method may further include providing an activated carbon fiber (ACF) filter material; pretreating the ACF filter material with a sodium bromide (NaBr) solution; placing the ACF filter material in the calibration tube; and sealing the calibration tube. In one embodiment of the method, pretreating the ACF filter material includes heating the ACF to 160°C for approximately 1.5 hours; encapsulating the ACF filter material in a glass chamber with a NaBr solution; and allowing the ACF filter material and the NaBr solution to equilibrate for at least 24 hours. In one embodiment of the method, the gas detector is configured to detect volatile organic compounds (VOCs). In one embodiment of the method, breaking a portion of the calibration tube includes breaking a first tip on one end of the tube and breaking a second tip on the other end of the tube. In one embodiment of the method, connecting the cap of the calibration tube to the housing includes threading the cap onto the housing.

[0043] Some embodiments of the disclosure may include a method for preparing a calibration tube for a gas detector, comprising providing an activated carbon fiber (ACF) filter material; pretreating the ACF filter material with a sodium bromide (NaBr) solution; placing the ACF filter material in the calibration tube; and sealing the calibration tube.

[0044] In one embodiment of the method, pretreating the ACF filter material includes heating the ACF to 160°C for approximately 1.5 hours, encapsulating the ACF filter material in a glass chamber with a NaBr solution, and allowing the ACF filter material and the NaBr solution to equilibrate for at least 24 hours. In one embodiment of the method, the method may further include breaking a portion of the calibration tube to allow air to flow through the calibration tube; inserting the calibration tube into a first portion of a probe connected to a gas detector; connecting a second portion of the probe to the first portion, wherein the second portion covers the calibration tube; and completing calibration of the gas detector during the insertion of the calibration tube into the probe. In one embodiment of the method, the method may further include using the gas detector to detect volatile organic compounds (VOCs).

[0045] In a first embodiment, a gas detector may include one or more sensing elements configured to detect volatile organic compounds (VOCs); and a probe configured to provide an air flow into the gas detector, wherein the probe includes: a housing configured to be connected to a body of the gas detector and configured to accommodate a calibration tube during calibration of the gas detector; a cap configured to be connected to the housing and configured to fit over and cover the calibration tube; and one or more inlets, wherein when the calibration tube is inserted into the probe, air flows through the calibration tube.

[0046] A second embodiment may include the gas detector of the first embodiment, wherein the calibration tube inserted into the probe comprises an activated carbon fiber (ACF) filter material.

[0047] A third embodiment may include the gas detector of the second embodiment, wherein the calibration tube inserted into the probe contains ACF filter material that has been pre-treated with a sodium bromide (NaBr) solution.

[0048] A fourth embodiment may include the gas detector of any of the first to third embodiments, wherein the calibration tube inserted into the probe includes a broken glass end to allow air to flow into and out of the calibration tube.

[0049] A fifth embodiment may include the gas detector of any one of the first to fourth embodiments, wherein the probe further includes threads between the housing and the cap.

[0050] A sixth embodiment may include the gas detector of any one of the first to fifth embodiments, wherein the probe further includes gripping elements on an exterior of at least one of the housing and the cap.

[0051] A seventh embodiment may include the gas detector of the sixth embodiment, wherein the probe further includes an O-ring configured to seal one end of the calibration tube when the calibration tube is inserted into the housing.

[0052] An eighth embodiment may include the gas detector of any one of the first to seventh embodiments, wherein the probe further includes an air inlet on the housing.

[0053] A ninth embodiment may include the gas detector of any one of the first through eighth embodiments, wherein the probe further includes an air inlet on the cap.

[0054] A tenth embodiment may include the gas detector of any one of the first to ninth embodiments, wherein the probe further includes a support block configured to seal the probe to the gas detector.

[0055] In an eleventh embodiment, a method for completing a calibration process of a gas detector may include providing a gas detector comprising a probe, wherein the probe comprises: a shell configured to be connected to a body of the gas detector and configured to accommodate a calibration tube during calibration of the gas detector; a cap configured to be connected to the shell and configured to be fitted over and cover the calibration tube; and one or more inlets, wherein air flows through the calibration tube when the calibration tube is inserted into the probe; breaking a portion of the calibration tube to allow air to flow through the calibration tube; inserting the calibration tube into the shell of the probe; connecting the cap of the probe to the shell, wherein the cap covers the calibration tube; completing calibration of the gas detector during insertion of the calibration tube into the probe; removing the calibration tube from the probe; and receiving a gas reading by the gas detector.

[0056] A twelfth embodiment may include the method of the eleventh embodiment, further comprising providing an activated carbon fiber (ACF) filter material; pretreating the ACF filter material with a sodium bromide (NaBr) solution; placing the ACF filter material in the calibration tube; and sealing the calibration tube.

[0057] A thirteenth embodiment may include the method of the twelfth embodiment, wherein pretreating the ACF filter material comprises heating the ACF to 160° C. for approximately 1.5 hours; encapsulating the ACF filter material in a glass chamber with a NaBr solution; and equilibrating the ACF filter material and the NaBr solution for at least 24 hours.

[0058] A fourteenth embodiment may include the method of any of the eleventh to thirteenth embodiments, wherein the gas detector is configured to detect volatile organic compounds (VOCs).

[0059] A fifteenth embodiment may include the method of any of the eleventh to fourteenth embodiments, wherein breaking the portion of the calibration tube includes breaking a first tip on one end of the tube and breaking a second tip on the other end of the tube.

[0060] A sixteenth embodiment may include the method of any of the eleventh to fifteenth embodiments, wherein connecting the cap of the calibration tube to the housing includes threading the cap onto the housing.

[0061] In a seventeenth embodiment, a method for preparing a calibration tube for a gas detector may include providing an activated carbon fiber (ACF) filter material; pretreating the ACF filter material with a sodium bromide (NaBr) solution; placing the ACF filter material in the calibration tube; and sealing the calibration tube.

[0062] An eighteenth embodiment may include the method of the seventeenth embodiment, wherein pretreating the ACF filter material comprises heating the ACF to 160° C. for approximately 1.5 hours; encapsulating the ACF filter material in a glass chamber with a NaBr solution; and equilibrating the ACF filter material and the NaBr solution for at least 24 hours.

[0063] A nineteenth embodiment may include the method of the seventeenth or eighteenth embodiment, further comprising breaking a portion of the calibration tube to allow air to flow through the calibration tube; inserting the calibration tube into a first portion of a probe connected to a gas detector; connecting a second portion of the probe to the first portion, wherein the second portion covers the calibration tube; and completing calibration of the gas detector during insertion of the calibration tube into the probe.

[0064] A twentieth embodiment may include the method of any one of the seventeenth to nineteenth embodiments, further comprising using the gas detector to detect volatile organic compounds (VOCs).

[0065] Although various embodiments according to the principles disclosed herein have been shown and described above, changes can be made to them by those skilled in the art without departing from the spirit and teachings of the present disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations and changes are possible and within the scope of the present disclosure. Alternative embodiments derived from the combination, integration and / or omission of features of one or more embodiments are also within the scope of the present disclosure. Therefore, the scope of protection is not limited by the description given above, but by the claims that follow, which include all equivalents of the subject matter of the claims. Each claim is incorporated into the specification as further disclosure, and the claims are one or more embodiments of one or more of the present invention. Further, any advantages and features described above may relate to specific embodiments, but the application of the claims issued in this way should not be limited to methods and structures that achieve any or all of the above advantages or have any or all of the above features.

[0066] In addition, the section titles used herein are provided to be consistent with the recommendations under 37 CFR 1.77 or to provide organizational clues. These titles should not limit or characterize the one or more inventions stated in any claims that may be issued according to the present disclosure. Specifically and as an example, although the title may be called "technical field", the claims should not be limited by the language selected under the title to describe the so-called field. Further, the description of the technology in "background technology" should not be interpreted as admitting that a certain technology is the prior art of any one or more inventions in the present disclosure. "Summary of the invention" should not be regarded as a limiting characterization of one or more inventions set forth in the claims issued. Further, any reference to "invention" in the singular in the present disclosure should not be used to argue that there is only a single novel point in the present disclosure. Multiple inventions can be set forth according to the limitations of multiple claims issued from the present disclosure, and such claims accordingly define the one or more inventions and their equivalents protected thereby. In all cases, the scope of the claims should be considered on their own value according to the present disclosure, and should not be constrained by the titles set forth herein.

[0067] The use of broader terms such as "comprising," "including," and "having" should be understood to provide support for narrower terms such as "consisting of," "consisting essentially of," and "composed substantially of." The use of the terms "optionally," "may," "might," "could," and the like with respect to any element of an embodiment means that the element is not required or, alternatively, is required, both options are within the scope of the one or more embodiments. Moreover, references to examples are provided for illustrative purposes only and are not intended to be exclusive.

[0068] Although several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The examples of the present disclosure are to be considered illustrative rather than restrictive, and are not intended to be limited to the details given herein. For example, various elements or components may be combined or integrated in another system, or certain features may be omitted or not implemented.

[0069] Moreover, the techniques, systems, subsystems and methods described and illustrated as discrete or separate in the various embodiments may be combined or integrated with other systems, modules, techniques or methods without departing from the scope of the present disclosure. Other items shown or discussed as being directly coupled or communicating with each other may be indirectly coupled or communicated through certain interfaces, devices or intermediate components, whether electrically, mechanically or otherwise. Other examples of changes, substitutions and alterations are ascertainable by those skilled in the art and may be made without departing from the spirit and scope disclosed herein.

[0070] The present application may also include the following implementation schemes.

[0071] 1. A gas detector (600), comprising:

[0072] one or more sensing elements configured to detect volatile organic compounds (VOCs); and

[0073] A probe (400) configured to provide air flow into the gas detector (600), wherein the probe (400) comprises:

[0074] a housing (402) configured to be connected to a body of the gas detector (600) and configured to house a calibration tube (500) during calibration of the gas detector (600);

[0075] a cap (404) configured to be connected to the housing (402) and configured to fit over the calibration tube (500) and cover the calibration tube (500); and

[0076] One or more inlets (410, 411, 412) wherein air flows through the calibration tube (500) when the calibration tube (500) is inserted into the probe (400).

[0077] 2. The gas detector (600) of claim 1, wherein the calibration tube (500) inserted into the probe (400) comprises an activated carbon fiber (ACF) filter material.

[0078] 3. The gas detector (600) of claim 2, wherein the calibration tube (500) inserted into the probe (400) comprises an ACF filter material that has been pre-treated with a sodium bromide (NaBr) solution.

[0079] 4. The gas detector (600) of claim 1, wherein the calibration tube (500) inserted into the probe (400) includes a broken glass end (508) to allow air to flow into and out of the calibration tube (500).

[0080] 5. The gas detector (600) of claim 1, wherein the probe (400) further comprises threads (403, 405) between the housing (402) and the cap (404).

[0081] 6. The gas detector (600) of claim 1, wherein the probe (400) further comprises a clamping element (414, 416) on the exterior of at least one of the housing (402) and the cap (404).

[0082] 7. The gas detector (600) of claim 1, wherein the probe (400) further comprises an O-ring (408) configured to seal one end of the calibration tube (500) when the calibration tube (500) is inserted into the housing (402).

[0083] 8. A method for completing a calibration process of a gas detector, comprising:

[0084] There is provided a gas detector comprising a probe, wherein the probe comprises:

[0085] a housing configured to be coupled to a body of the gas detector and configured to house a calibration tube during calibration of the gas detector;

[0086] a cap configured to be connected to the housing and configured to fit over and cover the calibration tube; and

[0087] one or more inlets, wherein air flows through the calibration tube when the calibration tube is inserted into the probe;

[0088] breaking a portion of the calibration tube to allow air to flow through the calibration tube;

[0089] inserting the calibration tube into the housing of the probe;

[0090] connecting the cap of the probe to the housing, wherein the cap covers the calibration tube;

[0091] completing calibration of the gas detector during the insertion of the calibration tube into the probe;

[0092] removing the calibration tube from the probe; and

[0093] A gas reading is received by the gas detector.

[0094] 9. The method of scheme 8 further comprises:

[0095] Provide activated carbon fiber (ACF) filter materials;

[0096] pretreating the ACF filter material with a sodium bromide (NaBr) solution;

[0097] placing the ACF filter material into the calibration tube; and

[0098] The calibration tube is sealed.

[0099] 10. The method of claim 9, wherein pretreating the ACF filter material comprises:

[0100] heating the ACF to 160° C. for about 1.5 hours;

[0101] encapsulating the ACF filter material in a glass chamber with the NaBr solution; and

[0102] The ACF filter material and NaBr solution were allowed to equilibrate for at least 24 hours.

Claims

1. A method for preparing a calibration tube for a gas detector, comprising: Provide activated carbon fiber (ACF) filter materials; Pre-treating the activated carbon fiber (ACF) filter material with a sodium bromide (NaBr) solution to enable the activated carbon fiber (ACF) filter material to maintain a humidity level greater than zero, wherein pre-treating the activated carbon fiber (ACF) filter material comprises: heating the activated carbon fiber (ACF) filter material to 160° C. for approximately 1.5 hours; encapsulating the activated carbon fiber (ACF) filter material in a glass chamber with a salt bath solution; and allowing the activated carbon fiber (ACF) filter material and the salt bath solution to equilibrate for at least 24 hours; placing the activated carbon fiber (ACF) filter material into the calibration tube; and The calibration tube is sealed.

2. The method of claim 1, wherein the salt bath solution comprises an alkali metal halide solution, potassium carbonate, magnesium nitrate or potassium sulfate.

3. The method of claim 1, further comprising: breaking a portion of the calibration tube to allow air to flow through the calibration tube; inserting the calibration tube into a first portion of a probe connected to the gas detector; connecting a second portion of the probe to the first portion, wherein the second portion covers the calibration tube; and Calibration of the gas detector is completed during the insertion of the calibration tube into the probe.

4. The method of claim 1, wherein the gas detector is operable to detect volatile organic compounds (VOCs).

5. A calibration tube for calibrating a gas detector, the calibration tube comprising: a cylindrical glass shell that defines the interior space; An activated carbon fiber (ACF) filter material is disposed within the interior space of the cylindrical glass shell, wherein the activated carbon fiber (ACF) filter material is pre-treated with a sodium bromide (NaBr) solution by a method comprising the steps of: heating the activated carbon fiber (ACF) filter material to 160° C. for approximately 1.5 hours; Encapsulating the activated carbon fiber (ACF) filter material in a glass chamber with a salt bath solution; and allowing the activated carbon fiber (ACF) filter material and the salt bath solution to equilibrate for at least 24 hours; a first breakable end configured to seal against a first end of the cylindrical glass envelope; and A second breakable end is configured to seal the second end of the cylindrical glass envelope.

6. The calibration tube of claim 5, wherein the salt bath solution comprises an alkali metal halide solution, potassium carbonate, magnesium nitrate, or potassium sulfate.

7. The calibration tube of claim 6, wherein the calibration tube is configured to be received into a calibration device, wherein the calibration device comprises: a housing configured to be coupled to a body of the gas detector and configured to house a calibration tube during calibration; a cap configured to be connected to the housing so as to fit over the calibration tube and cover the calibration tube; and One or more inlets are configured to allow air to flow through the calibration tube when the calibration tube is received in the calibration apparatus.

8. A calibration device comprising: a housing operatively connected to a body of the gas detector and operative to receive a calibration tube during calibration; a cap operatively connected to the housing and operable to fit over and cover the calibration tube; and one or more inlets, wherein air flows through the calibration tube when the calibration tube is inserted into the calibration apparatus, and wherein the calibration tube contains an activated carbon fiber (ACF) filter material that is pretreated with a sodium bromide (NaBr) solution to enable the activated carbon fiber (ACF) filter material to maintain a humidity level greater than zero, wherein the activated carbon fiber (ACF) filter material is pretreated by a method comprising the steps of: heating the activated carbon fiber (ACF) filter material to 160° C. for approximately 1.5 hours; Encapsulating the activated carbon fiber (ACF) filter material in a glass chamber with a salt bath solution; and The activated carbon fiber (ACF) filter material and the salt bath solution were allowed to equilibrate for at least 24 hours.

9. The calibration apparatus of claim 8, wherein the gas detector is operable to detect volatile organic compounds (VOCs).

10. The calibration device of claim 8, wherein the calibration tube further comprises a first tip on one end of the calibration tube and a second tip on the other end of the calibration tube, wherein the first tip and the second tip are broken during calibration of the gas detector.

11. The calibration apparatus of claim 8, wherein the salt bath solution comprises an alkali metal halide solution, potassium carbonate, magnesium nitrate, or potassium sulfate.

12. The calibration apparatus of claim 8, wherein a probe is connected to the gas detector and the calibration tube is inserted into the probe.

13. The calibration apparatus of claim 12, wherein the calibration tube inserted into the probe comprises a broken glass end, and wherein the broken glass end allows air to flow into and out of the calibration tube.

14. The calibration apparatus of claim 8, wherein the calibration tube comprises a glass shell.

15. The calibration device of claim 8, wherein the calibration tube maintains humidity at a point between 10-90% relative humidity RH.

16. The calibration apparatus of claim 8, wherein the calibration tube is packaged in a packaging box, wherein the packaging box includes a tube end breaker located on an exterior of the packaging box.

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