Method and system for limiting water in a photoionization detector

Abstract

Methods and systems for detecting and limiting water in a photoionization detector are provided. The method can include de-energizing a lamp configured to ionize particles of air. The method can also include monitoring a signal from the photoionization detector. The signal can be monitored based on a current between a signal electrode and a bias electrode. In an instance in which the signal is above a signal threshold, the method can also include electrolyzing one or more particles of water present in the photoionization detector by closing a leak switch to allow current to flow through the bias electrode and the signal electrode. In an instance in which the signal is below the signal threshold, the method can include energizing the lamp to begin photoionization detection. Corresponding systems are also provided.

Description

Technical Field

[0001] The present disclosure relates generally to methods, apparatus, and systems for limiting water accumulation in photoionization detectors (PIDs), and more particularly to methods and systems for detecting and removing accumulated water in PIDs. Background Art

[0002] Gas detectors can detect and / or measure the concentration levels of compounds (including, for example, organic and inorganic compounds) in gaseous substances. For example, a photoionization detector (PID) is a gas detector that can measure the concentration levels of volatile organic compounds in gaseous substances. The term "volatile organic compound" (or "VOC") refers to organic compounds that have a high vapor pressure at normal room temperature (i.e., they can readily transform into a gas or vapor). Exemplary chemical species within these VOCs include, for example, formaldehyde, methane, and benzene.

[0003] Typically, a PID consists of a short-wavelength ultraviolet (UV) lamp shining onto a small cell containing a gas sample. Within the cell is a set of electrodes, to which an electric potential is applied. The UV light photoionizes trace organic compounds (but not air), causing electrons to be emitted and forming positively charged molecules. The electrons and positive ions are driven toward the electrodes, and the resulting current is proportional to the gas or vapor concentration. In short, any compound with an ionization energy lower than the energy of the lamp's photons can be measured. High levels of volatile organic compounds (VOCs) in indoor or outdoor air can have adverse health and environmental impacts. For this reason, PIDs are used to measure and monitor VOC levels in a variety of indoor and / or outdoor locations.

[0004] As an industrial sensor, PID sensors may be exposed to high humidity environments. Humidity can lead to several issues, including sensor leakage. High humidity can also cause the current measured between the signal and bias electrodes during operation, leading to sensor inaccuracies. Through diligent effort, ingenuity, and innovation, many of these recognized issues have been addressed by developing solutions included in the embodiments of the present disclosure, many examples of which are described in detail herein. Summary of the Invention

[0005] Various embodiments described herein relate to methods, devices, and systems for limiting water accumulation in a PID. In an exemplary embodiment, a method for detecting water in a photoionization detector is provided. The method includes monitoring a signal from the photoionization detector. The signal is monitored based on a current between a signal electrode and a bias electrode. The method also includes electrolyzing one or more particles of water present in the photoionization detector by closing a leakage switch to allow current to flow through the bias electrode and the signal electrode when the signal is above a signal threshold.

[0006] In some embodiments, the method further comprises de-energizing a lamp configured to ionize airborne particles. In some embodiments, the method further comprises energizing a lamp configured to ionize airborne particles in the event that the signal drops below the signal threshold. In some embodiments, one or more particles of water present in the photoionization detector are electrolyzed within a housing of the photoionization detector.

[0007] In some embodiments, closing the leakage switch is configured to connect the signal electrode to at least one of a reference voltage or ground to allow current to flow through the bias electrode and the signal electrode. In some embodiments, the leakage switch is configured to be connected in parallel with the signal processing circuit. In some embodiments, de-energizing the lamp comprises opening a light switch, the light switch being configured to supply power to the lamp.

[0008] In some embodiments, the lamp is a short-wavelength ultraviolet (UV) lamp. In some embodiments, the photoionization detector is portable. In some embodiments, the method further comprises: while the lamp is powered off, closing a voltage bias switch configured to provide a voltage to a bias electrode. In some embodiments, monitoring the signal from the photoionization detector occurs while the lamp is powered off.

[0009] In another exemplary embodiment, a water detection system for a photoionization detector is provided. The water detection system includes a signal electrode configured to be proximate to a bias electrode such that, in the presence of at least one of an organic compound or water in the photoionization detector, current is passed from the bias electrode to the signal electrode. The water detection system also includes a signal monitor configured to monitor a signal from the system. The water detection system also includes a leak switch configured to allow charge to flow through any water present, thereby causing electrolysis, in the event that the signal is above a signal threshold.

[0010] In some embodiments, the water detection system further comprises a lamp configured to ionize airborne particles. In some embodiments, the water detection system may further be configured to energize the lamp configured to ionize airborne particles in the event that the signal drops below the signal threshold. In some embodiments, one or more particles of water present in the photoionization detector are electrolyzed within the housing of the photoionization detector.

[0011] In some embodiments, the leakage switch is configured to connect the signal electrode to at least one of a reference voltage or ground to allow current to flow through the bias electrode and the signal electrode to electrolyze one or more particles of water. In some embodiments, the leakage switch is configured to be connected in parallel with a signal processing circuit.

[0012] In some embodiments, the water detection system further comprises a light switch configured to supply power to the light, wherein the light switch is opened to de-energize the light. In some embodiments, the water detection system further comprises a voltage bias switch configured to provide a voltage to a bias electrode. In such embodiments, the voltage bias switch is closed when the light is de-energized. In some embodiments, the signal monitor is configured to monitor signals from the system when the light is de-energized.

[0013] The above summary of the invention is provided merely to summarize some exemplary embodiments, so as to provide a basic understanding of some aspects of the present invention. Therefore, it will be appreciated that the above-described embodiments are merely examples and should not be construed as narrowing the scope or spirit of the present invention in any way. It will be appreciated that the scope of the present invention encompasses many possible embodiments in addition to those summarized herein, some of which will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The description of the illustrated embodiments may be read in conjunction with the accompanying drawings. It will be appreciated that, for simplicity and clarity of illustration, the elements illustrated in the drawings are not necessarily drawn to scale unless otherwise indicated. For example, the dimensions of some elements may be exaggerated relative to other elements unless otherwise indicated. Embodiments incorporating the teachings of the present disclosure are shown and described with respect to the drawings presented herein, in which:

[0015] Figure 1 illustrates an exemplary schematic diagram showing an exemplary photoionization detector lamp according to various embodiments of the present disclosure;

[0016] Figure 2 is a flow chart illustrating various embodiments of the present disclosure (e.g. Figure 3-5 ) of PID operation;

[0017] Figure 3 illustrates a PID circuit diagram configured with a water detection system according to an exemplary embodiment of the present disclosure;

[0018] Figure 4 illustrates another PID circuit diagram configured with a water detection system according to an exemplary embodiment of the present disclosure;

[0019] Figure 5 illustrates yet another PID circuit diagram configured with a water detection system according to an exemplary embodiment of the present disclosure;

[0020] Figure 6 Another flow chart is shown that illustrates various embodiments of the present disclosure (e.g. Figure 7 ) of PID operation;

[0021] Figure 7 illustrates another PID circuit diagram configured with a water detection system according to an exemplary embodiment of the present disclosure;

[0022] Figure 8 is another flow chart illustrating the operation of a PID according to various embodiments of the present disclosure. DETAILED DESCRIPTION

[0023] Some embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the present disclosure. Indeed, the disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will satisfy applicable legal requirements. Throughout, like numbers refer to like elements.

[0024] The components illustrated in the drawings represent components that may or may not be present in the various embodiments described herein, such that an embodiment may include fewer or more components than those shown in the drawings without departing from the scope of the invention. Some components may be omitted from one or more of the drawings or shown in phantom to enable viewing of underlying components.

[0025] The phrases "in an exemplary embodiment," "some embodiments," "various embodiments," etc. generally mean that the particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of the present disclosure, and may be included in more than one embodiment of the present disclosure (importantly, such phrases are not necessarily referring to the same embodiment).

[0026] The word “example” or “exemplary” is used herein to mean “serving as an example, instance, or instance.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

[0027] If the specification indicates that a component or feature "may," "can," "could," "should," "might," "preferably," "likely," "usually," "optionally," "for example," "often," or "might" (or other such language) is included or has a characteristic, the particular component or feature is not required to be included or have that characteristic. Such a component or feature may optionally be included in some embodiments, or it may be excluded.

[0028] As mentioned above, exemplary PIDs can accumulate water due to condensation and humidity. Furthermore, using conventional methods to heat the sensor to remove the water can require significant and / or inefficient energy consumption. Because of this, and because water in the PID can affect signal readings during operation, removing the water can be beneficial to ensuring the accuracy and precision of the PID. Various exemplary embodiments of the present disclosure can eliminate the presence of water in the PID, thereby allowing for consistent signal readings while maintaining energy efficiency.

[0029] Now refer to Figure 1 , provides an exemplary schematic diagram illustrating an exemplary photoionization detector lamp 100 according to various embodiments of the present disclosure. Specifically, the exemplary photoionization detector lamp 100 may include a glass tube member 101 and a window member 103.

[0030] In some examples, glass tube member 101 may include a gaseous substance or a combination of gaseous substances, which may include, but are not limited to, inert gases such as argon (Ar), xenon (Xe), and / or krypton (Kr). In some embodiments, a single gas may be used in glass tube member 101. Alternatively, a mixture of gases may be used in glass tube member 101. The amount and type of gas in glass tube member 101 may be determined by the desired energy level of the UV lamp. The gaseous substance(s) in glass tube member 101 may be excited using any of a variety of excitation methods to generate an ultraviolet (UV) light source. For example, a voltage (e.g., an alternating current (AC) voltage) may be applied to glass tube member 101. In such examples, the AC voltage may cause the gaseous substance(s) in glass tube member 101 to ionize, resulting in a glow discharge. The glow discharge associated with the plasma may emit low-wavelength ultraviolet (UV) light.

[0031] Back to reference Figure 1, ultraviolet light can be transmitted through window member 103. In some examples, window member 103 may include material(s) that enable and / or facilitate the transmission of low-wavelength ultraviolet light, including, for example, salt crystal material. As ultraviolet light passes through window member 103, molecules in the gaseous substance may be exposed to the ultraviolet light and detected by the photoionization detector.

[0032] In some exemplary embodiments, a photoionization detector may be configured to detect volatile organic compounds (VOCs), such as in air. In this regard, an anode element (e.g., bias electrode 110) and a cathode element (e.g., signal electrode 115) are provided. In some examples, the anode element may be an electrode that attracts negatively charged electrons. In some examples, the cathode element may be an electrode that attracts positively charged electrons.

[0033] like Figure 1 As shown, air may flow through the photoionization detector in the direction indicated by arrow 105. The air may include VOC molecules 109 and non-VOC molecules 107. As the VOC molecules 109 and non-VOC molecules 107 pass through the photoionization detector, they may be exposed to the ultraviolet light generated by the photoionization detector lamp 100. Specifically and as shown Figure 1 As shown, ultraviolet light can cause photoionization of VOC molecules 109, which can cause electrons from the VOC molecules 109 to be emitted and form positively charged ions. The electrons can travel to an anode element (e.g., bias electrode 110), while the positively charged ions can travel to a cathode element (e.g., signal electrode 115). As the electrons and positively charged ions are driven to their respective electrodes, an electric current can be generated.

[0034] In contrast, UV light does not cause photoionization of non-VOC molecules (e.g., non-VOC air) 107. As a result, non-VOC molecules 107 do not generate an electrical current. In other words, the electrical current generated by UV light photoionization is proportional to the amount of VOC molecules 109 in the air. Because of this, the concentration level of volatile organic compounds (VOCs) can be determined, in some examples, using a photoionization detector based at least in part on electrical current.

[0035] In some exemplary embodiments, a photoionization detector relies at least in part on the photoionization of molecules by ultraviolet light generated by the photoionization detector lamp. However, for the photoionization detector to operate within desired tolerances, PIDs need to remove, limit, or account for false signals generated by leakage and / or noise from other sources. In particular, water accumulation within the system due to high humidity, for example, can cause inaccurate voltage readings. In this regard, various embodiments of the present disclosure may be embodied as systems and devices for limiting or otherwise eliminating water in the PID lamp 100.

[0036] Now refer to Figure 2 , provides a method according to an exemplary embodiment (e.g. Figure 3-5 Flowchart of the operation of the photoionization detector (PID circuit diagram shown in FIG) to detect and remove water in the PID using two switches. Unless expressly stated otherwise, Figure 2 The operation can be performed by Figure 3-5 Refer to the PID circuit diagram shown. Figure 2 At block 200, the method includes powering the photoionization detector. In some embodiments, the PID may already be powered (eg, during operation, which may be done intermittently).

[0037] Now refer to Figure 2 At block 210, the method includes turning on the light switch 320 to de-energize the lamp 100. In some embodiments, the lamp 100 may be configured to Figure 1 The lamp 100 described above operates in the same manner as described above. In the event that the lamp 100 is powered off, photoionization ceases and the current generated by the photoionization also ceases. In some embodiments, the light switch 320 can be configured to complete the lamp driver circuit 305. Figure 3 As shown, for example, the light switch 320 can be configured to complete the lamp driver circuit 305 so that the lamp receives voltage from the power supply. In some embodiments, the light switch 320 can be an analog switch implemented by an integrated circuit, a simple metal oxide semiconductor field effect transistor (MOSFET) circuit, or another circuit implemented by discrete components. Figure 1 As discussed, when the lamp is powered on, VOC molecules passing through the lamp may be photoionized, thereby creating an electrical connection between bias electrode 110 and signal electrode 115. When the lamp 100 is powered off, the photoionization of the VOC molecules ceases, and the electrical connection between bias electrode 110 and the signal electrode is terminated. However, in some examples, if water is present in the PID, the electrical connection between bias electrode 110 and the signal electrode may not be terminated.

[0038] Now refer to Figure 2 At block 220 , the method includes monitoring a signal from the photoionization detector. In some embodiments, the monitored signal may be a current, a voltage, or the like. In some embodiments, the signal may be determined by an analog-to-digital converter (ADC). For example, the ADC may read a varying voltage and output a signal indicating the voltage value. In some embodiments, the signal monitoring may be performed by the signal processing circuit 310 (e.g., the ADC may be part of the signal processing circuit 310). In some embodiments, the monitoring may be initiated after the lamp 100 has been powered off.

[0039] Now refer to Figure 2 At decision block 230 , the photoionization sensor determines, for example, via a processor, whether the signal exceeds a signal threshold. In some embodiments, when the lamp 100 is powered off, the PID signal (e.g., voltage) may be zero or near zero. In exemplary embodiments, the water detection system may be configured to determine whether the PID signal experiences any substantial increase when the lamp 100 is powered off. For example, an ADC may be configured to read the signal value, and the processor may be configured to determine whether the signal exceeds a signal threshold. In some embodiments, the signal threshold may be based on the PID device resolution during operation. For example, if the device resolution is 0.3 millivolts, the signal threshold may range from 3 millivolts to 300 millivolts. In some embodiments, the device resolution and / or signal threshold may be adapted for different gas concentration levels. In some embodiments, the water detection system may be configured with a signal threshold such that a signal above the threshold indicates the presence of water in the system. In some embodiments, the signal threshold may be set based on the amount of water allowed in the PID, the accuracy of the monitoring component, and / or similar factors. For example, the amount of signal increase may be correlated with the amount of water present in the PID.

[0040] Now refer to Figure 2 In block 240, in the event that the signal is determined to be above the signal threshold, the leakage switch 315 is closed. Figure 3 and Figure 4 As shown and in some exemplary embodiments, closing of leakage switch 315 connects signal electrode 115 to ground. In some embodiments, leakage switch 315 can be an analog switch implemented by an integrated circuit, a simple metal oxide semiconductor field effect transistor (MOSFET) circuit, or another circuit implemented by discrete components. In some embodiments, for example Figure 5 , the closure of the leakage switch 315 connects the signal electrode 115 to the reference voltage. In some embodiments, in the presence of water in the PID, the leakage switch 315 connects the signal electrode 115 to ground (e.g., Figure 3 and Figure 4 ) or a reference voltage (e.g. Figure 5 ) may allow current to flow from the bias electrode 110 (which is connected to the DC bias voltage 300 ) into the signal electrode 115 .

[0041] In some embodiments (e.g. Figure 5In the illustrated embodiment, the leak switch 315 can be configured in parallel with the signal processing circuit 310. When the leak switch 315 is closed, current is passed through the water 325 present in the PID, causing the water to be electrolyzed (e.g., H2O is converted to H2 and O2). In some embodiments, the converted H2 and O2 can be carried out of the PID through the PID outlet, much like other gases. For example, the PID can be configured with a gas passage 205 having an inlet and an outlet at each end of the PID, so that the converted H2 and O2 continuously flow out of the PID through the PID outlet. In some embodiments, after the water in the PID has been electrolyzed, a signal from the system (e.g., current or voltage) can be monitored to determine whether the signal is now below a signal threshold, indicating that the water has been eliminated.

[0042] In some exemplary embodiments, monitoring of the signal (e.g., such as shown in block 220) may continue during the electrolysis process. In some examples, electrolysis may be stopped once the signal falls below a signal threshold. However, in alternative embodiments, the signal may not be monitored during electrolysis, and monitoring may be resumed after the leak switch 315 is opened. In yet another alternative embodiment, the leak switch 315 may be closed for a set amount of time (e.g., 5 seconds). In various embodiments, the signal may be monitored during and / or after the electrolysis process to determine whether the signal is still above the signal threshold.

[0043] Now refer to Figure 2 In block 250 , if the signal is below the signal threshold, the leak switch is opened or remains open and the light switch is closed. That is, if the initial signal is below the signal threshold, the minimum amount of electrolyzed water is not present in the PID. In some embodiments, if the signal threshold has previously been monitored to be above the signal threshold, the leak switch 315 will remain open. In some embodiments, if the leak switch 315 has previously been closed (e.g., if water has already been electrolyzed by the PID), the leak switch 315 may be opened. In some embodiments, if the signal is below the signal threshold, the light switch 320 may be closed, thereby energizing the light.

[0044] Now refer to Figure 2 In block 260, with the light switch 315 closed, photoionization detection is resumed. In some embodiments, closing the light switch 315 energizes the lamp 100 and then allows the PID to perform photoionization detection. In some embodiments, Figure 2 The operations shown can be repeated, for example at regular intervals. In some embodiments, Figure 2The illustrated operation may be repeated based on user input (e.g., a user may be able to activate the water detection system). In various embodiments, the regularity of water detection may additionally or alternatively be based on the environment of use, water level tolerances, PID operation (e.g., the water detection system may be activated during short periods of low PID usage), and / or similar factors.

[0045] Now refer to Figure 3-5 , provides circuit diagrams of various exemplary embodiments according to the present disclosure. Unless otherwise indicated, various circuit configurations can be used, for example, water can be removed from a PID by relying on various combinations of the exemplary circuits discussed herein.

[0046] Now refer to Figure 3 , shows a simplified PID circuit diagram according to an exemplary embodiment. In various embodiments, the lamp driving circuit 305 may include a power source 335 (e.g., an alternating current (AC) power source), a lamp switch 320, a lamp driving converter 330, and a lamp 100, the lamp driving converter 330 being configured to convert AC to direct current (DC). Additionally, the PID may have a bias electrode 110 configured to be proximate to the lamp and in electrical communication with the DC bias voltage 300. In some embodiments, the PID may also have a gas passage 105 defined between the bias electrode 110 and a signal electrode 115. Additionally, the signal electrode 115 may be connected to the signal processing circuit 310 and a leakage switch 315, which may be connected to ground, as shown. Figure 3 As shown. When the leak switch 315 is closed, a current is generated between the bias electrode 110 and the signal electrode 115, allowing water present in the PID (e.g., water 325) to be electrolyzed. In some embodiments, the quality of the leak switch 315 can affect the time required to electrolyze any water present in the PID. For example, a higher quality leak switch can allow for faster electrolysis of water present in the PID.

[0047] Now refer to Figure 4, shows a PID circuit diagram according to an exemplary embodiment. In various embodiments, the lamp driving circuit 305 may include a power supply 335 (e.g., an alternating current (AC) power supply), a light switch 320, a lamp driving converter 330, and a lamp 100, the lamp driving converter 330 being configured to convert the AC to a direct current (DC), for example, the DC voltage may be relatively low, from 3 to 30 volts, while the AC voltage is relatively high, from 200 to 2000 volts. In some embodiments, the light switch 320 may be configured to allow the lamp 100 to be powered when the light switch 320 is closed. In addition, the PID may have a bias electrode 110, which is configured to be in proximity to the lamp 100 and electrically connected to the DC bias voltage 300. In some embodiments, the DC bias voltage may be from 10 to 100 volts. In some embodiments, the PID may also have a gas passage defined between the bias electrode 110 and the signal electrode 115. In addition, the signal electrode 115 may be connected to the signal processing circuit 310, including a leakage switch 315, which may be connected to ground, such as Figure 4 As shown. When the leakage switch 315 is closed, a current flows between the bias electrode 110 and the signal electrode 115, allowing water present in the PID to be electrolyzed. In some embodiments, the signal processing circuit 310 may further include an operational amplifier, a resistor (e.g., a resistor of 1 megohm to 1 gigaohm), and a capacitor (e.g., a capacitor of 100 picofarad to 100 nanofarad) for monitoring the PID. In some embodiments, the operational amplifier, resistor, and capacitor operate at high impedance, so that the system signal is low when the lamp is powered off. In some embodiments, the signal processing circuit 310 may further include a microcontroller and / or an integrated circuit. In such embodiments, the microcontroller and / or integrated circuit may allow the signal processing circuit 310 to integrate the signal within the PID. In some embodiments, the signal may be directly input to the signal processing circuit 310.

[0048] Now refer to Figure 5, shows a PID circuit diagram according to an exemplary embodiment. In various embodiments, the lamp driving circuit 305 may include a power supply 335 (e.g., an alternating current (AC) power supply), a lamp switch 320, a lamp driving converter 330, and a lamp 100, the lamp driving converter 330 being configured to convert AC to direct current (DC), for example, the DC voltage may be relatively low, from 3 to 30 volts, while the AC voltage is relatively high, from 200 to 2000 volts. In addition, the PID may have a bias electrode 110, which is configured to be in the vicinity of the lamp 100 and electrically connected to the DC bias voltage 300. In some embodiments, the DC bias voltage may be from 10 to 100 volts. In some embodiments, the PID may also have a gas passage defined between the bias electrode 110 and the signal electrode 115. In addition, the signal electrode 115 may be connected to the signal processing circuit 310, including a leakage switch 315. In some embodiments, the leakage switch 315 may be configured to be connected in parallel with the signal processing circuit 310, such as Figure 5 As shown. When leakage switch 315 is closed, a current flows between bias electrode 110 and signal electrode 115, allowing water present in the PID to be electrolyzed. In some embodiments, signal processing circuit 310 may further include an operational amplifier, a resistor (e.g., a resistor with a range of 1 megohm to 1 gigaohm), and a capacitor (e.g., a capacitor with a range of 100 picofarad to 100 nanofarad). In some embodiments, the operational amplifier, resistor, and capacitor operate at high impedance, ensuring that the system's signal is low when the lamp is powered off. In some embodiments, signal processing circuit 310 may further include a microcontroller and / or an integrated circuit. In such embodiments, the microcontroller and / or integrated circuit may allow signal processing circuit 310 to integrate the signal within the PID. In some embodiments, the signal may be directly input to signal processing circuit 310.

[0049] Now refer to Figure 6 , provides a method according to an exemplary embodiment (e.g. Figure 7 Flowchart of the operation of the photoionization detector (PID circuit diagram shown) to detect and remove water in the PID using three switches. Figure 7 The PID circuit diagram of FIG. 1 may be configured with a light switch configured to energize the lamp 100, a bias voltage switch 700 configured to electrically connect the DC bias voltage 300 to the bias electrode 110, and a leakage switch 315 configured to electrolyze water in the PID. Figure 6 The method includes energizing the photoionization detector at block 600. The operation of block 600 may be the same as that described above with respect to Figure 2 The same as discussed in block 200 .

[0050] Now refer to Figure 6At decision block 610, the method includes opening or leaving leakage switch 315 and light switch 320 open while simultaneously closing or leaving voltage bias switch 700 closed. In some embodiments, voltage bias switch 700 may be an analog switch implemented by an integrated circuit, a simple metal oxide semiconductor field effect transistor (MOSFET) circuit, or another circuit implemented with discrete components. In some embodiments, leakage switch 315 may remain open during the operations of block 610. In some embodiments, voltage bias 700 may already be closed when light switch 320 is closed, and the voltage bias switch may remain closed. In some embodiments, according to the systems and methods disclosed herein, the opening and / or closing of each switch may be performed immediately or continuously.

[0051] Referring now to block 620, the method includes monitoring a signal of the PID when the light switch 320 is on and the voltage bias switch is closed. In various embodiments, the monitoring of the signal may be similar to that discussed above with respect to Figure 2 The same as discussed in block 220 of FIG. Figure 6 At decision block 630, the method includes determining whether the signal is above a signal threshold. Figure 2 The signal threshold is set as discussed in decision block 230 of FIG.

[0052] In some embodiments, the method may include monitoring the PID signal when all three of the leakage switch 315, the light switch 320, and the voltage bias switch 700 are open. In some embodiments, a malfunction of the signal processing circuit 310 may generate a false signal. In the event that the leakage switch 315, the light switch 320, and the voltage bias switch 700 are open, a non-zero signal may indicate a malfunction of the signal processing circuit 310. In some embodiments, an error message may be displayed (visually, audibly, strategically, etc.) based on a possible signal processing circuit 310 malfunction.

[0053] Now refer to Figure 6 At block 640, in the event that the signal is above the signal threshold, the light switch 320 remains open, while the leakage switch 315 is closed and the voltage bias switch 700 remains closed. In various embodiments, in the event that the signal is above the signal threshold, an undesirable level of water may be present in the PID. In some embodiments, for example Figure 7In the PID circuit diagram shown, when both the leakage switch 315 and the voltage bias switch 700 are closed, water in the PID can be electrolyzed, as discussed herein. In some embodiments, only water between the bias electrode 110 and the signal electrode 115 may cause a false signal to be observed. In some embodiments, when both the leakage switch 315 and the voltage bias switch 700 are closed (if applicable), only water between the bias electrode 110 and the signal electrode 115 can be electrolyzed, as discussed herein.

[0054] Now refer to Figure 6 At block 650, the method includes closing the light switch 320 if the signal is not above the signal threshold. Figure 2 In some embodiments, when the light switch 320 is closed, the lamp 100 may be powered on and photoionization detection may be initiated and / or otherwise restored. Figure 6 The operation can be repeated intermittently, such as by user input or at a set time period. In some embodiments, the voltage bias switch 700 remains closed, thereby allowing ionization detection to occur.

[0055] Now refer to Figure 7 , a PID circuit diagram according to an exemplary embodiment is provided. Figure 7 The PID circuit diagram shown can be configured to perform Figure 6 The operation discussed. A PID circuit diagram according to an exemplary embodiment is shown. In various embodiments, lamp driver circuit 305 may include a power source 335 (e.g., an alternating current (AC) power source), a light switch 320, a lamp driver converter 330, and lamp 100. Lamp driver converter 330 is configured to convert AC to direct current (DC). For example, the DC voltage may be relatively low, ranging from 3 to 30 volts, while the AC voltage may be relatively high, ranging from 200 to 2000 volts. In some embodiments, light switch 320 may be configured to allow lamp 100 to be powered when light switch 320 is closed.

[0056] Additionally, the PID may include a bias electrode 110 configured to be positioned proximate to the lamp 100 and electrically connected to the bias voltage source 300. In some embodiments, the bias voltage source 300 may be an AC power source, and the bias converter 710 may be configured to convert the AC to DC. For example, the bias voltage supplied to the bias electrode 110 may be tens of volts. However, in some embodiments, such as battery-powered portable devices, the bias voltage source may operate at a lower voltage, allowing a converter to be used to achieve the desired voltage. Furthermore, the voltage bias switch 700 may be configured to allow current to reach the bias converter 710. In some embodiments, the PID may also include a gas path defined between the bias electrode 110 and a signal electrode 115. In some embodiments, the signal electrode 115 may be connected to the signal processing circuit 310, including a leakage switch 315, which may be connected in parallel with the rest of the signal processing circuit 310. When leakage switch 315 is closed and voltage bias switch 700 is closed, a current flows between bias electrode 110 and signal electrode 115, allowing water present in the PID to be electrolyzed. In some embodiments, signal processing circuit 310 may further include an operational amplifier, a resistor (e.g., a resistor of 1 megohm to 1 gigaohm), and a capacitor (e.g., a capacitor of 100 picofarad to 100 nanofarad) for monitoring the PID. In some embodiments, the operational amplifier, resistor, and capacitor operate at high impedance, so that the system signal is low when the lamp is powered off.

[0057] Now refer to Figure 8 , provides yet another flow chart illustrating the operation of a photoionization detector for detecting and removing water from a PID according to an exemplary embodiment. The operations discussed herein may include Figure 2 and Figure 6 Unless explicitly stated otherwise, the operations discussed in

[0058] Now refer to Figure 8 At block 800, the method includes de-energizing the lamp 100, which is configured to ionize air particles. As discussed above, de-energizing the lamp 100 can be achieved by turning on the light switch 315, which is connected to the lamp power supply 335. Figure 8 At block 810, the method includes monitoring a signal from a photoionization detector while the lamp is powered off. Various monitoring methods may be used, such as with respect to, for example, Figure 2 and Figure 6As discussed above. For example, a signal (e.g., a voltage from the signal processing circuit) can be monitored when the lamp 100 is powered off (e.g., the light switch 320 is turned on). In various embodiments, the signal can include current, voltage, etc. In some embodiments, when the lamp 100 is powered off and there is little or no water in the PID, the signal can be relatively low. For example, when the lamp 100 is powered off and there is no water in the PID, the voltage reading can be zero or close to zero. In some embodiments, the signal processing circuit 310 can be configured to monitor the signal at various times, including when the lamp 100 is powered off. When the monitored signal is above a signal threshold (e.g., indicating that a certain amount of water is present in the PID), the PID is configured to electrolyze the water present in the PID.

[0059] In some embodiments, the signal primarily comes from ions and electrons, such as in water. In such embodiments, the signal can be generated by a current passing through the bias electrode 110 and the signal electrode 115. In some embodiments, the signal current can be converted into a signal voltage by the signal processing circuit 310, and the signal voltage can be converted into a digital value, for example, by an ADC. In some embodiments, the signal processing circuit 310 may include a microcontroller or the like to process the digital value. For example, the microcontroller may process the digital value using firmware and / or software logic.

[0060] Now refer to Figure 8 At block 820 of the method, the method includes electrolyzing one or more particles of water present in the photoionization detector when the signal is above a signal threshold. The electrolysis of water molecules to convert H2O into H2 and O2 was discussed above. As discussed above, the electrolysis of water molecules can occur when a current is generated between the bias electrode 110 and the signal electrode 115. In an exemplary embodiment, a current is generated between the bias electrode 110 and the signal electrode 115 when water is present and the leakage switch 315 is closed such that the signal electrode 115 is connected to ground or a reference voltage. Additionally, in some embodiments, the PID may further include a voltage bias switch 700 configured to provide a voltage to the bias electrode 110. In such embodiments, both the voltage bias switch 700 and the leakage switch 315 may need to be closed in order to electrolyze water in the PID.

[0061] Now refer to Figure 8 At block 830, the method includes energizing a lamp configured to ionize particles of the air in the event that the signal drops below a signal threshold. Figure 2 and Figure 6 As discussed, the lamp 100 may be energized by closing the light switch 315. In some embodiments, energizing the lamp 100 may initiate photoionization detection of the PID, for example, by detecting a photoionization signal of the PID. Figure 1 The ionization in question.

[0062] In various embodiments, one or more of the operations discussed in blocks 800 through 830 may be repeated at various times to determine whether water is present in the PID. For example, the water level may be checked every minute or every hour of operation. In some embodiments, the length of time required for electrolysis may depend on the amount of time between detection and removal of water. For example, while monitoring a signal to determine whether it is above a signal threshold may take a similar amount of time to complete (e.g., detection of water may only take one minute), electrolyzing water in the PID may take longer if the time between water detections is longer (e.g., more water may have accumulated, thus taking longer to electrolyze more water).

[0063] Various embodiments of the present disclosure may be embodied as a method for providing a water detection system in a photoionization detector (PID) lamp. In this regard, Figure 2 、 Figure 7 and Figure 8 Each depicts a flowchart illustrating an exemplary method according to various embodiments of the present disclosure. In some examples, each block of the flowchart and combinations of blocks in the flowchart can be implemented by various means, such as hardware, firmware, circuits, and / or other devices associated with the execution of software (including one or more computer program instructions).

[0064] In some examples, Figure 2 、 Figure 7 and Figure 8 One or more of the steps described may be implemented by computer program instructions, which may be stored in a memory circuit (e.g., a non-transitory memory) of a system employing embodiments of the present disclosure and executed by a processing circuit (e.g., a processor) of the system. These computer program instructions may direct the system to operate in a specific manner such that the instructions stored in the memory circuit produce an article of manufacture, the execution of which implements the functions specified in the flowchart block(s). In addition, the system may include one or more other circuits. The various circuits of the system may be electrically coupled to each other and / or to each other to transmit and / or receive energy, data, and / or information.

[0065] In some examples, embodiments may take the form of a computer program product on a non-transitory computer-readable storage medium storing computer-readable program instructions (e.g., computer software). Any suitable computer-readable storage medium may be used, including a non-transitory hard disk, CD-ROM, flash memory, optical storage device, or magnetic storage device.

[0066] With the benefit of the teachings presented in the foregoing description and the associated drawings, many modifications and other embodiments of the inventions set forth herein will come to mind to those skilled in the art to which these inventions pertain. It should be understood, therefore, that these inventions are not limited to the specific embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated drawings have described exemplary embodiments in the context of certain exemplary combinations of elements and / or functions, it should be appreciated that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, combinations of elements and / or functions other than those explicitly described above are also contemplated as being illustrative in some of the appended claims. Although specific terms are employed herein, they are used in a broad and descriptive sense only and are not intended to be limiting.

Claims

1. A method for detecting water in a photoionization detector, the method comprising: monitoring a signal from the photoionization detector, wherein the signal is monitored based on a current between a signal electrode and a bias electrode; and In case the signal is above a signal threshold, one or more particles of water present in the photoionization detector are electrolyzed by closing a leakage switch so as to allow current to flow through the bias electrode and the signal electrode.

2. The method of claim 1, further comprising de-energizing a lamp configured to ionize particles of the air.

3. The method of claim 2, further comprising energizing the lamp in the event that the signal drops below the signal threshold, the lamp being configured to ionize particles of the air.

4. The method according to claim 1, wherein One or more particles of water present in the photoionization detector are electrolyzed in the housing of the photoionization detector.

5. The method according to claim 1, wherein Closing the leakage switch is configured to connect the signal electrode to at least one of a reference voltage or ground so as to allow current to flow through the bias electrode and the signal electrode.

6. The method according to claim 5, wherein: The leakage switch is configured to be connected in parallel with the signal processing circuit.

7. The method of claim 2, wherein: De-energizing the light includes turning on a light switch configured to supply power to the light.

8. The method of claim 2, wherein: The lamp is a short wavelength ultraviolet (UV) lamp.

9. The method of claim 1, wherein: The photoionization detector is portable.

10. The method of claim 2, further comprising: In a condition where the lamp is de-energized, a voltage bias switch is closed, the voltage bias switch being configured to provide a voltage to the bias electrode.

11. The method of claim 2, wherein: Monitoring the signal from the photoionization detector occurs with the lamp de-energized.

12. A water detection system for a photoionization detector, the water detection system comprising: a signal electrode configured to be proximate to a bias electrode such that, in the presence of at least one of an organic compound or water in the photoionization detector, current flows from the bias electrode to the signal electrode; a signal monitor configured to monitor a signal from the water detection system; and A leakage switch is configured to enable charge to flow through any water present, thereby causing electrolysis, in the event that the signal is above a signal threshold.

13. The water detection system of claim 12, further comprising a lamp configured to ionize particles of the air.

14. The water detection system of claim 13, further configured to energize the lamp in the event that the signal drops below the signal threshold, the lamp configured to ionize particles of the air.

15. The water detection system according to claim 12, wherein: One or more particles of water present in the photoionization detector are electrolyzed in the housing of the photoionization detector.

16. The water detection system according to claim 12, wherein: The leakage switch is configured to connect the signal electrode to at least one of a reference voltage or ground to allow current to flow through the bias electrode and the signal electrode to electrolyze one or more particles of water.

17. The water detection system according to claim 16, wherein: The leakage switch is configured to be connected in parallel with the signal processing circuit.

18. The water detection system of claim 13, further comprising a light switch configured to power the light, wherein The light switch is turned on to de-energize the light.

19. The water detection system of claim 13, further comprising a voltage bias switch configured to provide a voltage to the bias electrode, wherein In the event that the lamp is de-energized, the voltage bias switch is closed.

20. The water detection system of claim 13, wherein: The signal monitor is configured to monitor a signal from the system in a situation where the lamp is de-energized.

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