WO2006012777A1

WO2006012777A1 - An integrated photoionization sensor

Info

Publication number: WO2006012777A1
Application number: PCT/CN2004/000905
Authority: WO
Inventors: Yongbiao Qian; Hongtao Sun; Weili Yeh; Aimin Su
Original assignee: Rae Systems (Shanghai) Inc.
Priority date: 2004-08-06
Filing date: 2004-08-06
Publication date: 2006-02-09
Also published as: CN101006339B; CN101006339A

Abstract

The invention provides an integrated photoionization sensor (10), which includes not only an ionization chamber (36), an ultraviolet (UV) lamp (32), driving electrodes (40, 42), and an ionization detector (48), but also general circuits, such as a lamp driving circuit (44) and a bias circuit (54). Said photoionization sensor of present invention includes a support element (230), which separates the space within a sensor housing into two parts. Said ionization chamber (36), said ultraviolet (UV) lamp (32), said driving electrodes (40, 42), and said ionization detector (48) are disposed in one of the two parts, and the general circuits are integrated in a circuit board (95) disposed in the other part. The space where the circuit board (95) lies is filled with a sealing adhesive to avoid contacting with the outwards. The top cover of he sensor housing is provided with a single big hole or fence or net shape ventilating window, so the sensor (10) fits both for a gas pumping mode, and for a diffusion mode. In the case that the sensor (10) s not taken apart, Said ventilating window permits the optical window (34) of UV lamp (32) being leaned without using an air pump. Said circuit board is also integrated with a photosensor (20), so the UV lamp's working states can be known without dismounting the sensor (10).

Description

Integrated photoionization sensor

The invention relates to a photoionization sensor, in particular to an integrated photoionization sensor. Background technique

A photoionization detector (PID) detects volatile organic gases or compounds. Figures 1 and 2 show a conventional PID 30. The PID 30 includes an ultraviolet (UV) lamp 32 that radiates UV photons or ultraviolet light into the ionization chamber 36 through the optical window 34. The UV photons collide with the volatile gas molecules in the ionization chamber 36, causing the ionization energy to ionize the molecules below the photon energy, producing detectable ions and electrons.

As shown in Figure 2, the UV lamp 32 includes a sealed bulb 38 which is preferably made of glass. The lamp tube 38 contains a mixed gas composed of a plurality of inert gases. For example, the mixed gas is at 25 Torr and contains 40% helium, 30% argon, and 30% helium. The tube has a diameter of 0.25-0.5 inches and a length of 0.5-1.5 inches. The optical window 34 is made of a single crystal material and is located at one end of the bulb 38. For example, the optical window 34 can be made of materials such as lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), barium fluoride (BaF ₂ ), or calcium fluoride (CaF ₂ ), which allow for 11.7 eV, respectively. , UV photon transmission of 10.6eV, 9.8eV and 9.2eV energy. The UV lamp 32 is located between the two sheet-like drive electrodes 40 and 42, and the drive electrode pads 40 and 42 are connected to the lamp drive circuit 44. The drive electrode sheets 40 and 42 may be made of a copper sheet and may have a size of about 0.20 inches by 0.20 inches. The lamp driving circuit 44 supplies an AC signal having a frequency of about 100 kHz and a voltage of about 650 to 1250 V to the driving electrode sheets 40 and 42. Thus, a strong electric field is generated in the bulb 38, and the inert gas in the tube is ionized into electrons and ions. Then, the electrons and ions in the tube recombine to produce UV photons. This process is called glow discharge. Based on the different choices of materials for the optical window 34, UV photons having a certain level of energy can pass through the optical window 34. The lamp drive circuit 44 produces a high voltage AC signal across the drive pads 40 and 42 which is described in U.S. Patent 5,773,883. U.S. Patent No. 5,773,883, the disclosure of which is incorporated herein by reference in its entirety in its entirety in its entirety in The microprocessor 46 can adjust the high voltage AC signal applied to the driving electrode sheets 40 and 42, and thereby adjust the intensity of the ultraviolet light of the UV lamp 32. Microprocessor 46 can also be used to minimize the energy consumption of UV lamp 32, as described in U.S. Patent 6,225,633. U.S. Patent No. 6,225,633, the disclosure of which is incorporated herein to

1 Confirmation here.

The UV photons from the UV lamp 32 ionize the volatile gas molecules within the ionization chamber 36. Ion detector 48 is located within ionization chamber 36 and is adjacent to optical window 34 for collecting ions and ions generated by ionization. The ion detector 48 includes a pair of electrodes which are a bias electrode 50 and a measuring electrode 52. The biasing electrode and the measuring electrode are in the form of a sheet, may be linear or stepped, and may be arranged in an interdigitated structure. The bias electrode 50 and the measuring electrode 52 may be made of various metals and alloys, preferably stainless steel.

Bias circuit 54 provides a bias voltage to bias electrode 50 (e.g., a DC voltage of about 4-120V). Thus, the bias electrode 50 repels the positive ions generated by photoionization. The measuring electrode 52 is close to the ground voltage and is spaced apart from the bias electrode 50, thus forming an electric field between the bias electrode 50 and the measuring electrode 52. The measuring electrode 52 absorbs positive ions and generates a measuring current. The measuring circuit 56 is connected to the measuring electrode 52 and measures the current generated by collecting the positive ions, that is, the current is measured. Microprocessor 46 is coupled to both bias circuit 54 and measurement circuit 56, on the one hand to adjust the bias voltage applied by bias circuit 54 to bias electrode 50 and, on the other hand, to receive measurement current from measurement circuit 56. Signal to determine the concentration of volatile gases. Since the value of the measured current depends on the amount of ions generated, it is related to the concentration of ionizable molecules in the ionization chamber 48 and the intensity of the UV light. If the UV light intensity is constant, then the measured current can be converted to a concentration of volatile organic gases (in parts per million, ppm)

In addition, ultraviolet light is emitted to the bias electrode 50 and the measuring electrode 52 to release electrons. The electrons released by the bias electrode 50 are generally absorbed by the bias electrode 50, so that no background current (i.e., current when no ionizable gas is present) is generated. However, the electrons released by the measuring electrode 52 cause a background current. The background current is a factor that must be considered when determining the concentration of volatile gases. Thus, it is recommended to mount a UV shield 62 between the optical window 34 and the measuring electrode 53 for preventing UV light from being incident on the bias electrode 50 and the measuring electrode 52.

The PID 30 also includes an air pump 74 that allows the airflow to exit the ionization chamber 36 through the inlet 114 and the outlet 116 at a rate of 200-600 ml/min. When the air pump is turned on, the ionization chamber 36 is an open container that can receive laminar gas. When the air pump is turned off, the ionization chamber 36 is a closed container and gas cannot enter or exit the ionization chamber. The air pump 74 is connected to the air pump drive circuit 76, and the air pump drive circuit 76 is connected to the microprocessor 46. The microprocessor 46 controls the opening, closing, and pumping speed of the air pump 74 through the air pump drive circuit 76.

Generally, the UV lamp 32, the driving electrodes 40 and 42, the ionization chamber 36, and the ion detector 48 are mounted in the casing 78 to constitute an integrated PID sensor element, and the lamp driving circuit, the air pump driving circuit, and the bias in the PID. Circuits, measuring circuits, microprocessors, and other circuit portions for operating the sensor elements form the PID body. The air pump can be built into the PID sensor element or it can be placed in the PID body. jobs When the PID sensor element is inserted into the PID body, it is in electrical contact with the circuit in the PID body. This is described in U.S. Patent No. 6,313,638, the disclosure of which is incorporated herein by reference.

As described above, when the UV light intensity is constant, the measured current can be converted into a concentration of a volatile gas. However, the UV light intensity is generally attenuated by various factors during operation of the PID 30, including degradation of the UV lamp 32, contamination of the optical window 34, and introduction of interfering substances into the ionization chamber 36. The contamination of the optical window 34 is typically during the normal use of the PID 30, a layer of polymer coating is formed on the window due to the deposition of metal atoms, oil films or dust particles. In order to clean the optical window 34, the user typically needs to disassemble the PID sensor element 30. In order to avoid disassembly of the PID sensor element, U.S. Patent 6,225,633 provides a self-cleaning PID system. In the self-cleaning system, when the air pump 74 is turned on, the ionization chamber 36 is an open container, and the pumping operation of the air pump introduces a gas containing oxygen into the ionization chamber 36. Then, the air pump 74 is turned off, and the ionization chamber 36 is turned into a closed container. The UV light of the UV lamp 32 is incident on the ionization chamber 36 to convert the oxygen therein into ozone. Ozone accumulates in the ionization chamber, thereby removing contaminants from the optical window 34.

The traditional PID has the following problems:

In the conventional PID, an integrated PID sensor component is composed of a UV lamp, a driving electrode, an ionization chamber, and an ion detector, and is composed of a lamp driving circuit, an air pump, a gas pump driving circuit, a bias circuit, a measuring circuit, a microprocessor, and Other circuit portions for operating the sensor elements form the PID body. When working, insert the PID sensor element into the PID body. The conventional design does not place the circuit portion within the PID sensor element. Thus, even if the user purchases a PID sensor component from the market, he must build the PID body portion himself. In the PID body section, in addition to the measurement circuitry and the microprocessor must be designed as needed, the lamp driver circuitry, bias circuitry, and other circuitry for operating the sensor components are common. Obviously, it is inconvenient for each user to establish or separately purchase a component containing a general circuit portion when constructing the PID body portion. Therefore, it is desirable to provide a PID sensor element that can include a general purpose circuit.

Conventional PID sensor components are approximately 1.4 inches in diameter and are large in size. When it is desired to include the general-purpose circuit portion in the PID sensor element, the size of the PID sensor element must be further increased. Therefore, it is desirable to provide a miniaturized PID sensor element.

Conventional PID sensor components form a self-cleaning system that uses ozone to clean the contamination on the optical window. When it is desired to include the general circuit portion in the PID sensor element, ozone can affect the operation of the general circuit portion. In addition, when the PID sensor component is used in some dangerous situations, for example, working at a high temperature In a wet environment, or in a place with high corrosive gases, the external environment will also affect the normal operation of the general circuit. Therefore, it is desirable to provide a novel type of PID sensor component that allows the general circuit portion to be unaffected by the outside world.

The traditional PID self-cleaning system does not require disassembly, and ozone is used to clean the contamination on the optical window. However, the self-cleaning system requires the aid of an air pump and a gas pump drive circuit. Whether the air pump and air pump drive circuit are placed in the PID sensor element or in the PID body will increase the cost and increase the component volume. Therefore, it is desirable to provide a novel PID sensor element that can be cleaned without disassembly and without the use of an air pump and air pump drive circuit.

Traditional PID sensor components encapsulate the UV lamp in a metal enclosure. Since the housing is opaque, the operator does not know when the UV lamp fails. Therefore, it is desirable to provide a PID sensor element that provides a signal indicative of whether the UV lamp is operational. Summary of the invention

In view of the above problems in the prior art, it is an object of the present invention to provide an integrated PID sensor element including a universal circuit portion. ,

Another object of the present invention is to provide a compact integrated PID sensor component that includes a general purpose circuit portion.

It is still another object of the present invention to provide an integrated PID sensor element including a common circuit portion that is not affected by the outside world.

It is still another object of the present invention to provide a novel integrated PID sensor element that can be cleaned without disassembly and that does not require the use of an air pump and air pump drive circuit.

Another object of the present invention is to provide a novel integrated PID sensor element that can be used to know if a UV lamp is operating without disassembly.

According to the present invention, there is provided an integrated photoionization sensor comprising:

An ionization chamber configured to allow gas to flow in and out;

An ultraviolet lamp for injecting ultraviolet light into the ionization chamber to ionize the gas;

a driving circuit for generating a high voltage alternating current signal;

Driving electrodes, which are located outside the ultraviolet lamp and connected to the driving circuit for applying the high voltage alternating current signal to the ultraviolet lamp;

An ion detector, located in the ionization chamber, and including a bias electrode and a measuring electrode; a bias circuit for providing a bias voltage to the bias electrode for the bias electrode absorber a particle having a charge symbol, the measuring electrode absorbing particles having opposite charge symbols and providing a measurement signal;

a sensor housing having a venting window allowing said gas to flow into and out of said ionization chamber, and wherein all of said components are mounted within said sensor housing;

A plurality of external pins extending from the sensor housing for transmitting signals to and from the sensor housing.

In the integrated photoionization sensor of the present invention, a support member is further included. The support includes: a substrate, all components in the photoionization sensor are located on the substrate, and a plurality of external pins pass through the substrate; and a spacer located on the substrate to divide the internal space of the photoionization sensor housing into the first chamber And a second chamber for placing an ionization chamber, an ion detector, an ultraviolet lamp, a drive electrode, a second chamber for placing a drive circuit and a bias circuit, the spacer providing a plurality of openings to allow the drive electrode to The driving circuit is electrically connected, the bias electrode is electrically connected to the bias circuit, and the measuring electrode is electrically connected to the measuring signal output pin of the plurality of external pins.

In the present invention, the spacer may be a spacer perpendicular to the substrate.

In the present invention, the substrate may be circular, and the spacer is a hollow longitudinal cylinder having a longitudinal direction perpendicular to the substrate. The first chamber is formed by the interior of the longitudinal cylindrical spacer, and the second chamber is formed by the exterior of the longitudinal cylindrical spacer. The hollow portion of the longitudinal cylindrical spacer extends longitudinally beyond the top surface of the spacer, and the ultraviolet lamp and the drive electrode are located in the hollow portion. Additionally, the top surface of the longitudinal cylindrical spacer has a first recessed portion for receiving an ion detector, the first recessed portion being positioned such that the ion detector is aligned with the exit window of the ultraviolet lamp.

In the present invention, the ion detector may further include an ultraviolet shield for avoiding formation of a substrate current. The ultraviolet shielding plate comprises: a longitudinal through hole, the longitudinal through hole is aligned with an exit window of the ultraviolet lamp; a plurality of lateral elongated holes for inserting the bias electrode and the measuring electrode; and a plurality of lateral slender strips, which are located In the longitudinal through hole, aligned with the bias electrode and the measuring electrode, and between the bias electrode and the measuring electrode and the exit window of the ultraviolet lamp.

In the present invention, the driving electrode includes first and second driving electrodes attached to the outer wall of the ultraviolet lamp; the plurality of openings for electrically connecting on the spacer include first and second lateral grooves, which are located in the longitudinal section a longitudinal section of the cylinder extending toward the hollow portion of the longitudinal cylinder; the photoionization sensor further includes first and second driving electrode lead lines, wherein the first driving electrode lead line is electrically connected to the first driving electrode, and One end of a driving electrode lead wire extends out of the first lateral groove and is connected to the driving circuit, the second driving electrode lead wire is electrically connected to the second driving electrode, and one end of the second driving electrode lead wire extends out of the second lateral groove , Connected to the drive circuit.

In one version, the first and second drive electrodes are annular, they are parallel to one another and are distributed along the longitudinal direction of the ultraviolet lamp. At least one of the first and second lateral grooves is aligned with the corresponding annular drive electrode. The first lateral groove is located below the longitudinal section of the longitudinal cylinder and is offset from the first annular drive electrode, and the first drive electrode lead line is spiral.

In another aspect, the first and second drive electrodes are strip-shaped and are located on either side of the outer wall of the ultraviolet lamp and extend in the longitudinal direction of the ultraviolet lamp.

In the present invention, the drive electrode is coated, or plated, or vacuum evaporated onto the outer wall of the ultraviolet lamp. The driving electrode may also be a metal film and attached to the outer wall of the ultraviolet lamp.

In the present invention, the substrate and the spacer may be integrally formed. The plurality of openings for electrical connection on the spacer further includes first and second longitudinal through holes, the first longitudinal through holes providing passages for electrically connecting the measuring electrodes and the measurement signal output pins, and the second longitudinal through holes are bias electrodes Electrical connection to the ground pin provides access.

In the present invention, the first and second lateral grooves are closed with an adhesive. The binder can be an epoxy resin. In the present invention, the driving circuit and the bias circuit can be integrated on a circuit board. It is also possible to integrate the photosensor on the board, and the photosensor is located near the UV lamp to detect if the UV lamp is in operation. The longitudinal side of the longitudinal cylindrical spacer further includes a second recessed portion that is aligned with the ultraviolet lamp and the photosensor.

In the present invention, the binder is potted in the second chamber. The binder may be epoxy or plastic, or it may be a silicate or a phosphate.

In the present invention, an air guiding plate may be further included, the air guiding plate is adjacent to the ionization chamber, and includes an air guiding port for introducing the gas into the ionization chamber.

In the present invention, the sensor housing includes an end cap having a top surface having a venting window for gas to flow into and out of the ionization chamber. The venting window can be one or two circular holes, or grid or mesh, with the grid or mesh window aligned with the exit window of the UV lamp.

In the present invention, the material constituting all the components of the integrated photoionization sensor is suitable for stirring or ultrasonic cleaning in an organic solvent. Preferably, the materials constituting all of the components of the integrated photoionization sensor are also ozone resistant. The outer casing may be made of a metal material, preferably one selected from the group consisting of aluminum, copper, and stainless steel. The material constituting the gas guide plate, the ionization chamber, the substrate, the separator and the ultraviolet shield is fluoroplastic, preferably selected from the group consisting of polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FEP), and tetrafluoroethylene perfluoropropane. One of the vinyl ether copolymers (PFA). DRAWINGS

Figure 1 shows a circuit block diagram of a conventional PID;

Figure 2 shows an exploded perspective view of a conventional PID sensor element;

3 is a circuit block diagram of a PID in accordance with an embodiment of the present invention;

4 is an exploded perspective view of an integrated PID sensor element in accordance with an embodiment of the present invention; FIG. 5 is a block diagram showing an ion detector in accordance with an embodiment of the present invention;

6 is a structural view showing a UV lamp and a driving electrode according to an embodiment of the present invention;

FIG. 7 is a structural view showing a UV lamp and a driving electrode according to another embodiment of the present invention; FIG.

Figure 8 shows a structural view of a support member in accordance with an embodiment of the present invention. detailed description

Preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. In all the drawings, the same or similar components are denoted by the same reference numerals.

3 is a circuit block diagram of a PID in accordance with an embodiment of the present invention. The circuit structure of the PID of the present invention is basically the same as that of the conventional PID. The difference is that the present invention integrates the UV lamp 32, the drive electrodes 40 and 42, the ionization chamber 36, the ion detector 48, the lamp drive circuit 44, and the bias circuit 54 in the PID sensor element, while the measurement circuit 56 and the micro The processor 46 is disposed within the PID body. In the present invention, the air pump 74 and the air pump drive circuit 76 are optional. Additionally, the PID circuit of the present invention further includes a photosensor 20 located within the PID sensor element and disposed adjacent the outside of the UV lamp 32. The photosensor 20 detects whether the UV lamp is operating normally, and transmits the detection signal to the microprocessor 46 through the photosensitive detecting circuit 20'. If the detection signal indicates that the UV lamp is not lit, the microprocessor 46 issues an alarm signal to notify the operator.

4 shows an exploded perspective view of an integrated PID sensor element in accordance with an embodiment of the present invention. Among them, the sensor element 10 includes a housing 78. A support member 230 is incorporated in the outer casing 78. The support member 230 includes a base 200 and a spacer 202 that is placed perpendicular to the substrate. Figure 8 is an enlarged view of the support member 230. In the embodiment illustrated in Figure 8, the substrate 200 is a circular base plate and the spacer 202 is a longitudinally-cut half cylinder having a radius of the bottom surface that is substantially the same as the radius of the substrate 200, occupying substantially half of the area of the substrate. The spacer 202 divides the space on the substrate 200 into two portions. Inside the spacer 202, a UV lamp 32, drive electrodes 40 and 42, an ion detector 48 and an ionization chamber 36 are placed. On the outside of the spacer 202, a lamp driving circuit 44, a bias circuit 54, and a photosensor 20 are placed. As shown in FIG. 4, the lamp driving circuit 44, the bias circuit 54, and the photosensor 20 are integrated on the circuit board 95.

The substrate 200 and the spacer 202 may be discrete components that are held together by an adhesive such as epoxy. It can also be integrated. In the embodiment shown in Figure 4, the substrate 200 and the spacer 202 are integrated. The substrate 200 and the spacer 202 may be made of plastic, preferably of fluoroplastic, preferably of polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FEP), tetrafluoroethylene perfluoropropyl ethylene. Made of a base ether copolymer (PFA).

The interior of the spacer 202 includes a hollow portion 214 that is cylindrical and extends longitudinally beyond the top surface 210 of the spacer 202. The UV lamp 32 is placed within the hollow portion 214 with its optical window 34 positioned adjacent the top surface 210. The invention has a novel structure of a UV lamp and a drive electrode. Figures 6 and 7 illustrate two scenarios. Unlike the prior art, in the present invention, the drive electrodes are not sheet electrodes located on both sides of the UV lamp. As shown in Fig. 6, the first and second driving electrodes 40, 42 are annular and distributed longitudinally on the outer wall of the UV lamp tube 38. The drive electrodes 40 and 42 may be directly coated on the outer wall of the UV lamp tube 38 by brushing a metal material such as platinum, gold or the like or other non-metal conductive material and then curing by heating. Of course, the drive electrodes 40 and 42 can also be formed on the outer wall of the UV lamp tube 38 by electroplating or vacuum evaporation. It is also possible to stick a metal film on the outer wall of the UV lamp tube 38 to form the drive electrodes 40 and 42. Fig. 7 shows the shape of another example of the driving electrodes 40 and 42. In Fig. 7, the drive electrodes 40 and 42 are strip-shaped, extending in the longitudinal direction of the tube, and attached to both sides of the outer wall. By forming the driving electrodes 40 and 42 as a coating or film and directly attaching it to the outer wall of the UV lamp tube 38, the space occupied by the driving electrodes 40 and 42 can be reduced, and the dielectric loss can also be reduced.

Referring to Figures 6 and 8, in order to draw drive electrodes 40 and 42 out of spacer 202 and to circuit board 95, the present invention provides two horizontal lateral grooves 222 and 224 on longitudinal side 220 of spacer 202. The grooves 222 and 224 extend toward the inside of the separator 202 and communicate with the hollow portion 214. The first lateral groove 224 is located at the junction of the spacer 202 and the substrate 200. As shown in FIG. 6, since the end of the UV lamp tube 38 away from the optical window 34 is tapered, in order to achieve stable electrical contact, it is preferable to apply the first driving electrode 42 to the cylindrical portion of the UV lamp tube 38, so this The position of the first lateral groove 224 is not aligned with the first drive electrode 42. The first drive electrode lead wire 35 is bent into a spiral shape by a wire, and at least a portion of the spiral wire has a radius of rotation substantially the same as a radius of the outer wall of the UV lamp tube 38. During installation, the spiral wire is first flattened and inserted into the first lateral groove 224. Then, the spiral wire 35 is restored to its original shape by elasticity in the hollow portion 214 of the spacer 202. When the UV lamp 32 is inserted into the hollow portion 214, the first drive electrode 42 located below the lamp tube 38 is electrically connected to the spiral wire 35. The helical wire 35 includes a terminal 98. After the first drive electrode lead 35 is inserted into the first lateral recess 224, the terminal 98 remains outside of the spacer 202 for connection to the high voltage contact 98' on the circuit board 95 (see Figure 4). The position of the second lateral groove 222 is aligned with the second drive electrode 40 on the UV lamp tube 38. Second drive The pole lead 33 is bent into a "concave" shape by a wire, and the wire portion located inside the "concave" shape protrudes further inwardly to make electrical contact with the second drive electrode 40. During the mounting process, the second drive electrode lead-out line 33 is inserted into the second lateral groove 222 such that the protruding portion inside the first drive electrode lead-out line 35 is in electrical contact with the second drive electrode 40 on the UV lamp tube 38. The second drive electrode lead line 33 includes a terminal 90. After insertion of the second drive electrode lead-out line 33, the terminal 90 remains outside of the spacer 202 to be connected to the ground point 90' on the circuit board 95 (see Fig. 4). The first drive electrode lead line 35 and the second drive electrode lead line 33 are electrically connected to the lamp drive circuit 44 on the circuit board 95 via the high voltage contact 98' and the ground point 90' on the circuit board 95.

In the embodiment shown in Fig. 7, in order to cooperate with the strip drive electrodes 40 and 42, the drive electrode lead wires 35 and 33 can be bent into a "convex" shape by a wire. Each of the "convex" shaped wires projects partially outwardly adjacent one side of the tube 38 to conform to the cylindrical surface of the tube 38 in electrical contact with one of the drive electrodes 40 and 42. Also, in order to achieve stable electrical contact, strip drive electrodes 40 and 42 are preferably applied to the cylindrical portion of the bulb 38. In a preferred embodiment, the drive electrode lead lines 35 and 33 are arranged in the same plane. At this time, on the longitudinal side 220 of the spacer 202, only one lateral groove needs to be provided. Similarly, the two drive electrode lead wires 35 and 33 have terminals 98 and 90, respectively, which expose the spacer 202 after the lead wire is inserted into the corresponding groove, and the position of the high voltage contact 98' and the ground point 90' on the circuit board can be They are designed to be easily connected to terminals 98 and 90, respectively. Obviously, in the present invention, the potentials of the first drive electrode lead line 35 and the second drive electrode lead line 33 can be interchanged.

After the first drive electrode lead line 35 and the second drive electrode lead line 33 are respectively inserted into the corresponding lateral recesses, it is preferable to seal the recesses with an adhesive such as an epoxy resin. Closing the groove with an adhesive on the one hand secures the lead wire in the groove, keeping the lead wire in stable contact with the drive electrode, and on the other hand preventing the lead wire from slipping out of the groove and coming into contact with the circuit board 95.

As shown in FIG. 8, the top surface 210 of the spacer 202 has a recessed portion 212. The shape of the recessed portion 212 matches the shape of the ion detector 48 for housing the ion detector 48 and its electrode lead wires. FIG. 5 shows an example of the structure of the ion detector 48. Ion detector 48 includes a biasing electrode 50 and a measuring electrode 52 for generating a biasing electric field. The ion detector 48 also includes a UV shield 62 for avoiding the background current formed by the ultraviolet light incident on the measuring electrode 52. The UV shield 62 includes a through hole 36 that is aligned with the optical window 34 of the UV lamp 32. The through hole 36 and the space between the UV shield 62 and the optical window 34 constitute an ionization chamber. The bias electrode 50 and the measuring electrode 52 are needle-shaped and arranged in an interdigitated shape. The bias electrode 50 and the measuring electrode 52 may also be formed into a sheet shape as needed, and/or they may be arranged in a mesh shape. A plurality of lateral elongated holes are formed in the side of the UV shield 62 for inserting the bias electrode 50 and the measuring electrode 52. In order to avoid electrical contact between the bias electrode 50 and the measuring electrode 52, it is preferable to insert the bias electrode 50 and the measuring electrode 52 into the UV shield 62 in opposite directions. The bias electrode 50 and the measuring electrode 52 may be in the same plane or may have a top and bottom structure, whereby the bias electric field formed may be perpendicular or parallel to the ultraviolet light from the UV lamp 32 or at any angle with the ultraviolet light. In order to measure the ionizable gas more accurately, it is preferable to make the direction of the bias electric field perpendicular to the propagation direction of the ultraviolet light. The UV shield 62 also includes a plurality of lateral elongate strips within its through-holes 36 between the bias electrode 50 and the measurement electrode 52 and the optical window 34 of the UV lamp 32. The position and shape of the elongated strip can prevent ultraviolet light from being incident on the bias electrode 50 and the measuring electrode 52. As shown in FIG. 5, the elongated strip is located below the bias electrode 50 and the measuring electrode 52. The UV shield 62 may be made of fluoroplastic, preferably one of polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FEP), and tetrafluoroethylene perfluoropropyl vinyl ether copolymer (PFA). Made of species. The bias electrode 50 and the measuring electrode 52 may be made of a metal material such as stainless steel, aluminum, copper or the like or other non-metal conductive material.

Referring now to Figure 4, the support member 230 has a first longitudinal through bore 218 extending through the spacer 202 and the base 200 for receiving the measurement signal output pin 104. The lead wire 94 of the measuring electrode 52 is electrically connected to the measuring signal output pin 104 in the first longitudinal through hole 218. The spacer 202 includes a second longitudinal through hole 216 (see FIG. 8) through which the lead line 91 of the bias electrode 50 passes through the second longitudinal through hole 216 and is connected to the ground point 90' on the electrode plate 95, thereby being connected to the circuit board. The bias circuits on 95 are connected. In one embodiment of the invention, the bias electrode '50 is grounded and a voltage of 30V is applied to the measuring electrode 52. The measuring electrode 52 provides a measurement signal by collecting positive ions. However, the user can also apply a voltage higher than the bias electrode to the measuring electrode as needed to provide a measurement signal by collecting electrons.

Referring to Figure 8, the longitudinal side 220 of the spacer 202 has a second recessed portion 228. The position of the second recessed portion 228 is aligned with the UV lamp 32 within the hollow portion 214. The second recessed portion 228 does not penetrate the longitudinal side 220 of the spacer 202, the recessed depth of which is adapted to allow ultraviolet light to pass out of the recessed window 228. A photosensor 20 (not shown) is integrated on the circuit board 95. The position of the photosensor 20 is aligned with the second recessed portion 228 for receiving ultraviolet light escaping from the recessed window 228, and then the detection signal is transmitted to the contact 92' through the photosensitive detecting circuit 20' integrated on the circuit board 95.

Referring to FIG. 4, the PID sensor element 10 of the present invention includes a ground pin 100, a photo signal output pin 102, and a power input pin 106 in addition to the measurement signal output pin 104. As described above, the measurement signal output pin 104 passes through the first longitudinal through hole 218 on the support member 230 and is connected to the measurement electrode lead line 94. The grounding pin 100 passes through the through hole 90" in the support member 230, and is connected to the grounding point 90' on the circuit board 95 through a conductive connecting member (not shown), thereby causing the second driving electrode 40 of the UV lamp and The bias electrode 50 of the ion detector 48 is grounded. The photosensitive signal output pin 102 passes through the through hole 92" on the substrate 200, And connected to the contact 92' on the circuit board 95 through a conductive connector (not shown), and further connected to the photosensor 20 on the circuit board 95. Power input pin 106 passes through via 96" in substrate 202 and is coupled to contact 96' on circuit board 95 for providing electrical power to circuit board 95.

Alternatively, two longitudinal grooves may be selectively formed in the longitudinal side 220 of the spacer 202 to prevent deformation of the spacer 202.

During installation, after the UV lamp 32, the drive electrode lead wires 33 and 35, the ion detector 48, the circuit board 95, and the four external pins 100-106 are mounted to the support member 230, and after the relevant circuit connections are completed, The integral support member 230 is placed into the outer casing 78. The four external pins 100-106 on the support member 230 pass through corresponding through holes in the housing 78 for insertion into the PID body portion (not shown) during use.

Then, the adhesive is filled into the outer casing 78, outside the spacer 202, and the space in which the circuit board 95 is placed. The binder may be an organic binder, preferably an epoxy resin or a plastic, the binder may be an il-free binder, preferably a silicate or a phosphate. The binder should not readily react with the gas in the working environment of the sensor element. If the PID sensor element of the present invention is to be cleaned using an organic solvent (described below), the binder should also not readily react chemically with the organic solvent for cleaning. Encapsulating the space around the circuit board 95 with an adhesive can effectively prevent the circuit board 95 from coming into contact with corrosive gases in the working environment and organic solvents for cleaning.

Referring to Fig. 4, the PID sensor element 10 of the present invention further includes an air guide plate 110. Air deflector 110 is optional and is located above ion detector 48. The air guide plate 110 has an opening for guiding the flow direction of the air flow. The shape of the opening can be designed as needed.

The PID sensor element 10 of the present invention also includes an end cap 112. The top surface of the end cap 112 has a venting window that allows ionizable gas to flow into and out of the ionization chamber 36. As shown in Figure 4, in one embodiment of the invention, the venting window is grid-like and is comprised of two elongated vents 114 and 116. The venting window can also be a grid-like window formed by two or more elongated vents. The grid window allows the ionizable gas to flow into and out of the ionization chamber 36 by means of an air pump. At the same time, it can also be applied to the traditional ozone self-cleaning method. Preferably, the widths of the vents 114 and 116 can be designed to be large. At this time, the PID sensor element 10 of the present invention can cause the ionizable gas to flow into and out of the ionization chamber 36 by means of gas diffusion without using an air pump to pump. At the same time, the larger vent allows direct removal of contaminants from the optical window 34 by a cotton swab dipped in an organic solvent, and also allows the PID sensor element 10 to be placed in an organic solvent to be removed by agitation or ultrasonic waves on the optical window 34. Contaminants.

It is also possible to design the venting window on the top surface of the end cap 112 as a single circular hole or mesh structure. Like the grid window, the PID sensor element can be made by appropriately designing the size of the single circular hole window and the mesh window. 10 Not only for air pumping mode, but also for gas diffusion mode. In addition, proper design of the single circular aperture window and the mesh window may also allow for the removal of contaminants from the optical window 34 with a cotton swab containing organic solvent, or by agitation in an organic solvent, or by ultrasonic cleaning with a solvent solvent.

Of course, the ventilation window can also adopt a small window composed of double circular holes. This PID sensor element is only suitable for pumping ionizable gas with a gas pump, as well as the traditional ozone self-cleaning method.

To this end, preferably, the structure of the PID sensor element of the present invention and the materials of its various components can be adapted to be stirred in an organic solvent or ultrasonically cleaned in an organic solvent. Most preferably, the material of each component also has ozone resistance characteristics. For example, the outer casing 78 and the end cap 112 may be made of a metal material. Preferably, the metallic material is selected from one of aluminum, copper and stainless steel. The gas guide plate 110, the support member 230, and the ultraviolet protection plate are made of fluoroplastic, preferably polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FEP), tetrafluoroethylene perfluoropropyl vinyl ether copolymer. One of (PFA).

As described above, the PID sensor element of the present invention includes a general circuit portion such as a lamp driving circuit 44, a bias circuit 54, and the like. Therefore, after purchasing the PID sensor component, the user can directly insert into the PID body of the self-designed body, without separately purchasing circuit components including the lamp driving circuit 44 and the bias circuit 54, and designing the lamp driving circuit 44 when designing the PID body. And a bias circuit 54.

In order to reduce the size, the PID sensor element of the present invention integrates a circuit common portion such as a lamp driving circuit 44 and a bias circuit 54 on a circuit board. The novel support structure, ion detector structure, drive electrode structure, and drive electrode lead-out are also provided to miniaturize the PID sensor element of the present invention. In a finished PID sensor component, the UV lamp has a diameter of about 0.25 inches and a length of less than 0.5 inches. The base diameter is slightly smaller than the outer casing diameter and the spacer height is less than 0.6 inches. The entire PID sensor element is approximately 0.8 inches in diameter and approximately 0.6 inches in height.

The novel venting window allows the PID sensor element to be used not only in the pumping mode but also in the gas diffusion mode. Therefore, the user can avoid the air pump and air pump drive circuit. On the other hand, when the PID sensor element is operated in the gas diffusion mode, the conventional ozone self-cleaning method is no longer feasible. The novel venting window design allows the PID sensor components to be cleaned by other mechanical or chemical means without disassembly.

In order to protect the circuit board from the corrosive gas in the working environment and the organic solvent for cleaning, the present invention fills the space of the circuit board with an adhesive to isolate the circuit board from the outside.

In order to understand the operation of the internal UV lamp without opening the PID sensor element, the present invention integrates a photosensor on the circuit board for monitoring whether the UV lamp is working normally, avoiding false alarms or missing measurement signals of the PID sensor component. . Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto. Various changes and modifications can be made by those skilled in the art based on the description below. For example, the shape of the substrate 200 can be selected in accordance with the shape of the outer casing 78, such as a square shape. The spacer 202 may be larger or smaller than a half cylinder, or may be combined with a square base to select a rectangle. In contrast to the preferred embodiment described above, the circuit board 95 can be placed inside the spacer 202 with the UV lamp 32, drive electrodes 40 and 42, ion detector 48 and ionization chamber 36 placed outside of the spacer 202. The spacer 202 can also be a simple spacer that divides the space on the substrate into two portions, a portion of which places the UV lamp 32, the drive electrodes 40 and 42, the ion detector 48, and the ionization chamber 36. Another portion of the space is used to place the circuit board 95. A plurality of openings for electrical connections are provided on the isolation panel. In the latter two cases, the UV lamp 32, the drive electrodes 40 and 42, the ion detector 48, and the ionization chamber 36 can be arranged in a conventional configuration.

Various changes and modifications may be made without departing from the spirit and scope of the invention. The scope of protection of the invention is defined by the appended claims.

Claims

Rights request

An integrated photoionization sensor, comprising:

An ionization chamber configured to allow gas to flow in and out;

An ultraviolet lamp for injecting ultraviolet light into the ionization chamber to ionize the gas; and a lamp driving circuit for generating a high voltage alternating current signal;

Driving electrodes, which are located outside the ultraviolet lamp and connected to the lamp driving circuit for applying the high voltage alternating current signal to the ultraviolet lamp;

An ion detector, located in the ionization chamber, and comprising a bias electrode and a measuring electrode; a bias circuit for providing a bias voltage to the bias electrode, so that the bias electrode absorbs a charge a symbolic particle, the measuring electrode absorbing particles having opposite charge symbols and providing a measurement signal;

2. The integrated photoionization sensor of claim 1 further comprising a support member, the support member comprising:

a substrate, all of the components in the photoionization sensor are located on the substrate, and the plurality of external pins pass through the substrate;

a spacer on the substrate, dividing an inner space of the photoionization sensor housing into a first chamber and a second chamber, the first chamber for placing the ionization chamber, the ion detector, The ultraviolet lamp, the driving electrode, the second chamber is for placing the lamp driving circuit and the bias circuit, and the spacer provides a plurality of openings to allow the driving electrode and the lamp driving circuit to be electrically Connected, the bias electrode is electrically connected to the bias circuit, and the measuring electrode is electrically connected to the measurement signal output pin of the plurality of external pins.

3. The integrated photoionization sensor of claim 2, wherein the spacer is a spacer perpendicular to the substrate.

4. The integrated photoionization sensor according to claim 2, wherein the substrate is circular, and the spacer is a hollow longitudinal cylinder having a longitudinal direction perpendicular to the substrate.

The integrated photoionization sensor according to claim 4, wherein an inner portion of the longitudinal cylindrical spacer constitutes the first chamber, and an outer portion of the longitudinal cylindrical spacer constitutes the Second room.

6. The integrated photoionization sensor of claim 4, wherein

a hollow portion of the longitudinal cylindrical spacer protrudes longitudinally from a top surface of the spacer, and the ultraviolet lamp and the driving electrode are located in the hollow portion;

The top surface of the longitudinal cylinder spacer has a first recessed portion for accommodating the ion detector, and the position of the first recessed portion is such that the ion detector and the exit window of the ultraviolet lamp quasi.

7. The integrated photoionization sensor of claim 6 wherein said ion detector further comprises an ultraviolet shield for avoiding the formation of a substrate current.

8. The integrated photoionization sensor of claim 7, wherein the ultraviolet protection panel comprises:

a longitudinal through hole, the longitudinal through hole being aligned with an exit window of the ultraviolet lamp;

a plurality of lateral elongated holes for inserting the bias electrode and the measuring electrode;

a plurality of lateral elongated strips located in the longitudinal through holes, aligned with the biasing electrodes and the measuring electrodes, and located at the exiting of the biasing electrodes and the measuring electrodes and the ultraviolet lamps Between windows.

The integrated photoionization sensor according to any one of claims 6 to 8, wherein the driving electrode comprises first and second driving electrodes attached to an outer wall of the ultraviolet lamp; The plurality of openings on the spacer for electrical connection include first and second lateral grooves that are located on a longitudinal section of the longitudinal cylinder and extend toward a hollow portion of the longitudinal cylinder;

The photoionization sensor further includes first and second driving electrode lead lines, wherein the first driving electrode lead line is electrically connected to the first driving electrode, and one end of the first driving electrode lead line protrudes from the a first lateral groove connected to the lamp driving circuit, the second driving electrode lead wire being electrically connected to the second driving electrode, and one end of the second driving electrode lead wire extending out of the second lateral groove , connected to the lamp drive circuit.

10. The integrated photoionization sensor according to claim 9, wherein the first and second driving electrodes are annular, which are parallel to each other and distributed along the longitudinal direction of the ultraviolet lamp.

11. The integrated photoionization sensor of claim 10, wherein at least one of the first and second lateral grooves is aligned with a respective annular drive electrode.

12. The integrated photoionization sensor of claim 11 wherein: said first cross The groove is located below the longitudinal section of the longitudinal cylinder and is offset from the first annular drive electrode, the first drive electrode lead line being spiral.

The integrated photoionization sensor according to any one of claims 9 to 12, wherein the first and second driving electrodes are strip-shaped, and they are located on both sides of the outer wall of the ultraviolet lamp. The longitudinal extension of the UV lamp.

14. The integrated photoionization sensor of claim 9, wherein the drive electrode is coated, or plated, or vacuum evaporated onto the outer wall of the ultraviolet lamp.

The integrated photoionization sensor according to claim 9, wherein the driving electrode is a metal thin film and is attached to an outer wall of the ultraviolet lamp.

16. The integrated photoionization sensor of claim 9 wherein:

The substrate is integral with the spacer;

The plurality of openings for electrical connection on the spacer further includes first and second longitudinal through holes, the first longitudinal through holes providing a channel for electrically connecting the measuring electrodes and the measurement signal output pins The second longitudinal through hole provides a channel for electrically connecting the bias electrode to the ground pin.

17. The integrated photoionization sensor of claim 9 wherein said first and second lateral grooves are closed with an adhesive.

18. The integrated photoionization sensor of claim 17, wherein the binder is an epoxy resin.

19. The integrated photoionization sensor of claim 2, 6-7 or 9, wherein said lamp driving circuit and said biasing circuit are integrated on a circuit board.

20. The integrated photoionization sensor of claim 19, further comprising: a photosensor integrated on the circuit board and located adjacent to the ultraviolet lamp for detecting whether the ultraviolet lamp is Is working.

21. The integrated photoionization sensor of claim 20, wherein the longitudinal side of the longitudinal cylindrical spacer further comprises a second recessed portion, the recessed portion and the ultraviolet lamp and the The photosensors are aligned.

The integrated photoionization sensor according to any one of claims 19 to 21, wherein an adhesive is potted in the second chamber.

23. The integrated photoionization sensor according to claim 22, wherein the binder is an epoxy resin or a plastic.

24. The integrated photoionization sensor of claim 22, wherein the binder It is a silicate or a phosphate.

25. The integrated photoionization sensor of any of claims 2, 6-7, 9 and 22, further comprising an air guide plate adjacent to said ionization chamber And including a gas guide for introducing a gas into the ionization chamber.

The integrated photoionization sensor according to any one of claims 2, 6-7, 9 and 22, wherein the sensor housing comprises an end cap, and a top surface of the end cap has the A venting window for the gas to flow into and out of the ionization chamber.

27. The integrated photoionization sensor of claim 26, wherein the venting window is one or two circular apertures.

28. The integrated photoionization sensor according to claim 26, wherein the vent window is in a grid shape, and the grid window is aligned with an exit window of the ultraviolet lamp.

29. The integrated photoionization sensor of claim 26, wherein the vent window is in the form of a mesh, the mesh window being aligned with an exit window of the ultraviolet lamp.

30. An integrated photoionization sensor according to any of the preceding claims, wherein the material constituting all of the components of the integrated photoionization sensor is adapted for agitation or ultrasonic cleaning in an organic solvent. .

31. An integrated photoionization sensor according to any of the preceding claims, wherein the material constituting all of the components of the integrated photoionization sensor has ozone resistance.

The integrated photoionization sensor according to claim 30 or 31, wherein the outer casing is made of a metal material.

The integrated photoionization sensor according to claim 32, wherein the metal material is one selected from the group consisting of aluminum, copper, and stainless steel.

The integrated photoionization sensor according to any one of claims 30 to 33, wherein the gas guide plate, the ionization chamber, the substrate, the spacer, and the The material of the UV protection board is fluoroplastic.

The integrated photoionization sensor according to any one of claims 34, wherein the fluoroplastic is selected from the group consisting of polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FEP), and tetrafluoroethylene. One of perfluoropropyl vinyl ether copolymers (PFA).