CN116735462A

CN116735462A - Real-time microorganism particle counter

Info

Publication number: CN116735462A
Application number: CN202310615597.XA
Authority: CN
Inventors: 羊强; 郑轶; 汪鑫; 绪明; 贺琨; 王小敏; 宋晓东
Original assignee: Mianyang Science And Technology City Advanced Technology Research Institute
Current assignee: Mianyang Science And Technology City Advanced Technology Research Institute
Priority date: 2023-05-29
Filing date: 2023-05-29
Publication date: 2023-09-12

Abstract

The application discloses a real-time microorganism particle counter.A laser emitter emits laser, a collimating mirror collimates the laser and sends the laser to a first resonant cavity lens, the first resonant cavity lens and a second resonant cavity lens reflect the collimated laser back and forth in a resonant cavity, a concave light collecting mirror reflects light emitted by laser irradiating microorganisms to a transmission mirror, the transmission mirror reflects the light to a grating lens and sends the light to a collecting mirror through a light filter, the grating lens interferes and diffracts the light and sends the light to a signal analysis system to convert the light into a first electric signal, the collecting mirror collects photons in the light to the signal analysis system to form a second electric signal, the signal analysis system comprehensively analyzes the first electric signal to obtain microorganism types, and the second electric signal is comprehensively analyzed to obtain the particle size of microorganisms and the number of microorganisms. The counter is compact in structure and high in sensitivity by removing unnecessary components. The resonant cavity enables laser to reflect back and forth in the cavity, so that the efficiency of laser-induced fluorescence is enhanced, and the light path is optimized.

Description

Real-time microorganism particle counter

Technical Field

The application relates to the field of suspended microorganism detection, in particular to a real-time microorganism particle counter.

Background

Microorganisms in the air are often the cause of various diseases, and are dispersed in the air in the form of aerosol, and are mainly divided into two forms: when sneeze, cough, singing or talking, the droplets are sprayed from the mouth and nose, and the microorganisms are attached to the droplets or form "droplet nuclei" by the evaporation of the droplets, and the droplets are rapidly dispersed in the room and float in the air for a long time. Secondly, the particles with the aerodynamic diameter of more than 10 mu m are attached to air particles, most of the particles with the aerodynamic diameter of less than 10 mu m can fall on the ground together with microorganisms, most of the particles (PM 10) with the aerodynamic diameter of less than 10 mu m float in the air for a long time, and most of the PM10 can enter the respiratory tract of a human body to cause harm to the health of the human body, so that the air quality is necessary to be detected.

The existing air microorganism detection method mainly adopts a microorganism culture method, the traditional microorganism culture method needs to sample air firstly, then culture the sampled air, and judge the type and the quantity of microorganisms in the detection air according to the number of bacterial colonies in a culture medium after a period of culture. The test method has the defects of complicated detection steps and long detection period, and also has the defect that some microorganisms which cannot be artificially cultured in a culture medium cannot be detected.

Therefore, in order to solve the problems of slow effect and low accuracy of the conventional microorganism culture method, a person skilled in the art develops a microorganism real-time detection device by using a laser-induced fluorescence technology, but after experimental verification, the detection device is found to have a series of problems of complex light path, huge overall structure, low sensitivity and the like, and cannot be well put into production and application, so how to provide a microorganism counting device with compact structure, small volume and high sensitivity according to actual production needs becomes a problem to be researched by a person skilled in the art.

Disclosure of Invention

The application aims to overcome the defects of the prior art and provide a real-time microorganism particle counter which adopts a novel light path and a novel photon counter, so that compared with the prior equipment, the real-time microorganism particle counter has the advantages of more compact structure, smaller volume and higher sensitivity. The aim of the application is achieved by the following technical scheme:

in a first aspect, the present application proposes a real-time microbial particle counter comprising: the system comprises an optical path system, an air path system and a signal analysis system;

the optical path system comprises a laser emitter, a collimating mirror, a first resonant cavity lens, a second resonant cavity lens, a concave light collecting mirror, a transmission mirror, a grating lens, an optical filter and a light collecting mirror;

the laser transmitter is used for emitting a plurality of lasers, the collimating mirror is used for collimating the lasers and then transmitting the lasers to the first resonant cavity lens, and the first resonant cavity lens and the second resonant cavity lens are used for reflecting the collimated lasers back and forth in the resonant cavity;

the air path system comprises an air inlet air tap and an air outlet air tap which are arranged in a straight line, microorganisms are arranged in air flow between the air inlet air tap and the air outlet air tap, and the air flow is perpendicular to laser in the resonant cavity;

the concave light collecting lens is used for reflecting light diffused by the laser irradiation microorganisms to the transmission lens, the transmission lens is used for respectively reflecting the light diffused by the laser irradiation microorganisms to the grating sheet and transmitting the light to the light collecting lens through the optical filter, the grating sheet is used for carrying out interference and diffraction on the light diffused by the laser irradiation microorganisms and transmitting the light to the signal analysis system to be converted into a first electric signal, and the light collecting lens is used for collecting photons in the received light diffused by the laser irradiation microorganisms to the signal analysis system to be converted into a second electric signal;

the signal analysis system is used for comprehensively analyzing the first electric signal to obtain microorganism types, and comprehensively analyzing the second electric signal to obtain the microorganism grain size and the microorganism quantity.

In one possible embodiment, the real-time microorganism particle counter further comprises a black body for absorbing the laser light in the resonator.

In one possible embodiment, the number of filters is two, for attenuating the fluorescence emitted by the laser-irradiated microorganisms and absorbing the laser light present.

In one possible embodiment, the real-time microorganism particle counter further comprises an external air pump that sends an air flow containing microorganisms from the air inlet air tap to the air outlet air tap.

In one possible implementation manner, the signal analysis system comprises a CCD image sensor and a solid single photon detection chip, wherein the CCD image sensor is used for obtaining the microorganism types according to the first electric signals, and the solid single photon detection chip is used for obtaining the microorganism particle size and the microorganism quantity according to the second electric signals.

In one possible embodiment, the solid state single photon detection chip comprises a single photon detector.

In one possible embodiment, the real-time microbial particle counter further comprises a housing employing a combination of threaded washer, pin.

In one possible embodiment, the focal length of the collimating lens, the concave collecting lens and the collecting lens is 8-10 mm, respectively and independently.

In one possible embodiment, the center of the air flow between the air inlet air tap and the air outlet air tap is at the focus of the collimating mirror.

In one possible embodiment, the signal analysis system further comprises a light sensitive element, which is located at the lower part of the solid single photon detection chip and is used for converting photons in light emitted by the microorganism irradiated by the received laser into a second electrical signal.

The above-mentioned main scheme of the application and its various further alternatives can be freely combined to form multiple schemes, which are all the schemes that the application can adopt and claim; and the application can be freely combined between the (non-conflicting choices) choices and between the choices and other choices. Various combinations will be apparent to those skilled in the art from a review of the present disclosure, and are not intended to be exhaustive or all of the present disclosure.

Drawings

Fig. 1 shows a schematic structure of a real-time microorganism particle counter according to an embodiment of the present application.

Icon: 001-a laser emitter; 002-collimator lens; 003-a first resonator lens; 004-concave collector mirror; 005-air tap; 006-a second resonator lens; 007-black body; 008-a first filter; 009-a second filter; 010-focus mirror; 011-a transmission mirror; 012-grating sheet; 013-CCD image sensor; 014—solid state single photon detection chip.

Detailed Description

Other advantages and effects of the present application will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present application with reference to specific examples. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.

All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

An optical resonant cavity: called resonant cavities, miniaturization, integration and versatility of the optical device can be achieved. The partial resonant cavity can realize the micro-nano level size and can meet the requirement of micro-integration. The optical resonator is formed by two planar or concave spherical mirrors perpendicular to the working medium axis, one of which has a slightly lower reflectivity, and if the transmissivity of this mirror is increased and the laser light is emitted from this side, it is called an output mirror. The reflectivity of the other mirror is higher and is close to 100%, the other mirror is called a total reflection mirror, and the two mirrors can be called a high reflection mirror and a low reflection mirror due to the high and low emissivity. The resonant cavity has two main characteristics: the optical gain is continuously carried out in the cavity by 'amplification', and the direction and the frequency of the light waves are directionally selected. The application adopts the resonant cavity to increase the action time and path of the laser and the sampling gas, mainly adopts the characteristic of amplification, and can lead the amplification of the resonant cavity to be thousands of times, so that the laser can be contacted with the sampling gas back and forth thousands of times even in a very short optical path range, and the generated fluorescence intensity is greatly increased.

CCD image sensor: the optical signal can be directly converted into an analog electronic signal by being applied to digital photography, astronomy, optical telemetry, high-speed photography and other technologies. The current signal is amplified and analog-to-digital converted to realize image acquisition, transmission, processing and reproduction. In the present application, the type of microorganism is identified by comparing the obtained fluorescence spectrum with the spectrum in the program setting by utilizing the characteristics and combining the interference and diffraction of the fluorescence spectrum induced by the laser by the grating sheet.

The solid single photon detection chip used in the application is a single photon detector, and specifically includes, but is not limited to, a SIPM solid single photon detection chip. The SIPM solid state single photon detection chip, also known as a silicon photomultiplier, is a solid state high gain radiation detector that produces an output current pulse after absorbing photons. These PN junction based sensors have single photon sensitivity that can detect wavelengths of light from near ultraviolet to near infrared. The high-sensitivity high-gain optical fiber sensor has the advantages that the high-sensitivity high-gain optical fiber sensor can bear the impact of a large load due to the compact structure, can realize high gain under the condition of low voltage, can realize the induction of single photons, and can meet the real-time monitoring requirement from single photons to thousands of photons. Because the number and the concentration of the microorganisms in the sampling gas can be induced by the laser to obtain photons with different numbers and concentrations, the photons can be reversely deduced out of the concentration of the microorganisms in the sampling gas according to the set proper proportionality coefficient after being captured by the SIPM solid single photon detection chip and converted into an electric signal, so that the particle size and the number of the microorganisms in the detection object can be monitored in real time.

Existing microorganism counting devices often suffer from the following problems:

firstly, in order to ensure the detection accuracy, a complex light path is often adopted, so that the optical signals are better concentrated in a sampling area of a sampling component. However, this tends to increase the volume of the whole module greatly, and the device to which the module is applied cannot be miniaturized, so that portability of the whole device is lost.

Secondly, in order to ensure the detection accuracy, various methods are often adopted to enhance various optical signals, and a high-power laser is generally adopted to enlarge the contact volume range of the sampling object and the laser, so that the sampling object can absorb specific wavelengths in the laser more, and fluorescence required by monitoring is better emitted. However, if a high-power laser is used, the more heat is dissipated as the power of the laser is higher. If not timely radiating and working light for a long time, the laser wavelength and output power can change, thereby affecting the stability. The heavy weight will not light or even burn out the entire laser. The detection device generally only radiates heat naturally, which is particularly serious. Meanwhile, the influence caused by manual operation errors such as a focusing position and the like in the assembly process can be increased along with the increase of the volume, and the working efficiency and the precision of the whole system can be influenced. The above drawbacks have a serious influence on the production and miniaturization of the detection apparatus.

Thirdly, the intuitiveness is insufficient. The principle of the laser-induced fluorescence technology for identifying microorganisms is as follows: some of the characteristic biomass of the microorganism, such as tyrosine, tryptophan, riboflavin, etc., is induced by laser light to generate fluorescence, and the fluorescence spectrum generated by these biomass is analyzed to obtain the information of the sampled particles. Laser-induced fluorescence techniques essentially detect characteristic biomass, thereby identifying microorganisms. Fluorescence has two types of characteristics, one is fluorescence spectrum, which is determined by the type of biomass and does not change with the concentration and quantity of microorganisms in the sampled gas. And the fluorescence intensity, the characteristics are determined by the concentration of biomass, namely the concentration and the quantity of the monitored microorganisms.

Typically, such devices employ only one second type of receiver, which recognizes the size and number of microorganism particles in the sample by receiving the number and concentration of photons to determine the intensity of the fluorescence distribution. Although the method can also complete auxiliary judgment of the microorganism types in an algorithm by combining the concentration interval of the biomass in the microorganism and the microorganism size interval corresponding to the biomass, the judgment method is not intuitive, and because the biomass characteristic intervals of the microorganisms are partially overlapped, misjudgment is caused in some cases. In view of the disadvantages of complex light path, huge overall structure and low sensitivity of the existing microorganism detection equipment, the existing microorganism detection equipment cannot be well put into practical production and application, and therefore, the application correspondingly improves the existing microorganism detection equipment based on the disadvantages.

The real-time microorganism particle counter provided by the embodiment of the application is based on the technical principle of laser-induced fluorescence biological detection, when microorganism particles pass through a gas circuit supplemented with a gas pump, fluorescence signals are generated by laser induction, and then the fluorescence signals are converted into different electrical signals through a signal processing system and then are analyzed and processed, so that the types, the particle sizes and the number of microorganisms are counted in real time. The real-time microorganism particle counter adopts a novel light path and a novel photon counter, and compared with the prior equipment, the real-time microorganism particle counter has the advantages of more compact structure, smaller volume and higher sensitivity, and is described in detail below.

Referring to fig. 1, fig. 1 shows a schematic structural diagram of a real-time microorganism particle counter according to an embodiment of the application, where the real-time microorganism particle counter includes: the optical path system comprises a laser transmitter 001, a collimating lens 002, a first resonant cavity lens 003, a second resonant cavity lens 006, a concave light collecting lens 004, a transmission lens 011, a grating lens 012, an optical filter and a light collecting lens 010. The light path system is used for exciting and separating fluorescence of microorganisms in the gas, and then the fluorescence is transmitted into the signal analysis system.

The laser transmitter 001 has low power and power consumption of less than 1w, can continuously work for 24 hours and still maintain the accuracy, and does not generate larger power floating. The collimator 002 is used for adjusting and precisely positioning the light beam, and its working principle is based on the law of reflection and refraction of light, and is generally composed of two parallel glass plates, the medium between which a transparent optical medium is sandwiched can be air, water or other transparent liquid, and the surfaces of both glass plates are coated with metal with high reflectivity, which can be silver or aluminum.

When light rays vertically enter the collimator 002, the light beam proceeds in the advancing direction due to the law of refraction of the light. However, when light enters the collimator 002 at a certain angle, the light beam is reflected back due to the law of reflection of the light. The reflected light is directed in the same direction as the incident light but in the opposite direction. The collimator mirror 002 can also change the deflection angle of the light by adjusting the distance between the two glass plates, which can be achieved by rotating or moving one or both glass plates. In addition, by changing the refractive index of the intermediate medium, the angle of deflection of the light can also be changed.

The laser emitter 001 is used for emitting most laser, the collimating mirror 002 is used for transmitting most laser to the first resonant cavity lens 003 after being collimated, the first resonant cavity lens 003 and the second resonant cavity lens 006 are used for reflecting the collimated laser back and forth in the resonant cavity, the resonant cavity lens does not need to generate laser, and a high-reflection lens (lens with more than 95% reflectivity) can be adopted. The resonant cavity lens can also be an F-P cavity formed by two plane mirrors, so that larger energy loss and larger error of the whole system caused by errors generated by misalignment of the lens in the assembly engineering can be avoided. The resonant cavity formed by the first resonant cavity lens 003 and the second resonant cavity lens 006 enables the laser light path to emit back and forth in the cavity, so that the efficiency of laser induced fluorescence is enhanced, and the working efficiency of the laser emitter 001 is higher.

Since the system operating temperature is primarily determined by the power of the laser transmitter 001, the high temperature for a long period of time will cause the power of the laser transmitter 001 to spontaneously decrease, while also affecting the operating life. The laser emitter 001 with lower power is adopted in the application, so that the working temperature of the system is lower without arranging a cooling system, and the normal working time of the whole detection equipment is longer on the premise of small volume. On the basis of ensuring the functions, the generated fluorescence has higher intensity compared with the fluorescence generated by the same power, and the detection sensitivity is further improved.

The concave light collecting mirror 004 is used for sending light diffused by the laser irradiation microorganisms to the transmission mirror 011, the transmission mirror 011 is used for respectively emitting the light diffused by the received laser irradiation microorganisms to the grating sheet 012, or reflecting to the light collecting mirror 010 through the optical filter, the grating sheet 012 is used for carrying out interference and diffraction on the light diffused by the laser irradiation microorganisms and sending the light to the signal analysis system to be converted into a first electric signal, and the light collecting mirror 010 collects photons in the light diffused by the received laser irradiation microorganisms into the signal analysis system to be converted into a second electric signal.

The signal analysis system is used for respectively carrying out comprehensive analysis on the first electric signals to obtain microorganism types, and carrying out comprehensive analysis on the second electric signals to obtain the microorganism grain size and the microorganism quantity. The signal analysis system may be composed of a CCD image sensor 013 and an integrated solid-state single photon detection chip 014, wherein the CCD image sensor 013 obtains the microorganism type according to the first electric signal, and the solid-state single photon detection chip 014 obtains the microorganism particle size and the microorganism number according to the second electric signal and further outputs to the display device. The main functional component of the solid single photon detection chip 014 is a single photon detector (SIPM), and the single chip microcomputer integrated with the SIPM chip is self-designed and manually adjusts errors through an adjusting comparator.

The gas circuit system comprises two gas nozzles 005, wherein the two gas nozzles 005 are arranged in a straight line and are divided into a gas inlet gas nozzle and a gas outlet gas nozzle, microorganisms are arranged in gas flow between the gas inlet gas nozzle and the gas outlet gas nozzle, and the gas flow is perpendicular to laser in the resonant cavity.

The real-time microorganism particle counter also comprises an external air pump, and the external air pump sends the air flow containing microorganisms from the air inlet air tap to the air outlet air tap to provide sampling gas for the real-time microorganism particle counter.

The real-time microorganism particle counter further comprises a black body 007, the black body 007 being for absorbing the laser light in the resonator. Since the laser light in the resonant cavity cannot be totally used for reflecting microorganisms to generate fluorescence, in order to avoid interference signals caused inside the real-time microorganism particle counter, the redundant laser light in the resonant cavity formed by the first resonant cavity lens 003 and the second resonant cavity lens 006 is reflected to the black body 007 to be absorbed. The black body 007 is a structure capable of absorbing the unnecessary laser wave without reflection, and should be miniaturized as much as possible.

The optical filters are used for attenuating and absorbing light emitted by microorganisms irradiated by laser, and filtering out other unnecessary light, so that the effect is better.

Compared with the traditional scattering light detector, the single photon detector in the embodiment of the application has the advantages of high sensitivity, high time resolution, multi-parameter detection, microminiaturization design and the like, so that the single photon detector can realize the rapid, accurate and real-time monitoring of the microorganism aerosol on the premise of ensuring the normal action of a light path, and in addition, after the single photon detector is used as a core to integrate and design a singlechip and a corresponding burning-in algorithm, the design of the expected size and function can be well completed, and the sensitivity of the whole real-time microorganism particle counter can be improved.

The real-time microbial particle counter according to the embodiments of the present application eliminates unnecessary optical components and includes only a few necessary components, 1 non-necessary component (black body 007) and a housing without changing the power and other conditions of the laser transmitter 001. The collimating lens 002, the concave light collecting lens 004 and the light collecting lens 010 all adopt small focal lengths, the focal lengths of the collimating lens 002, the concave light collecting lens 004 and the light collecting lens 010 are respectively and independently preferably 8-10 mm, such as 8mm, 9mm and 10mm, and the problem of short optical path caused by miniaturization of equipment and insufficient fluorescent light intensity can be well solved by adopting the lens in the range. In addition, the real-time microorganism particle counter also comprises a shell, the shell adopts the combination of threads, gaskets and pins, the size of a final finished product is extremely small on the premise of ensuring the adjustable light path through a mechanical structure, and the final finished product can be used as a detection module to be placed in various instruments, so that the real-time microorganism particle counter has extremely high practicability and use value.

The working flow of the real-time microorganism particle counter provided by the embodiment of the application is as follows: the outside air pump sends the sampling gas that contains microorganism to the gas outlet air cock from the air inlet air cock, has formed a stable air current between two air cock, calculates the design in advance to the air current for the center of air current just is in the focus department of collimating mirror, and laser simultaneously launches from laser emitter, focuses on in the air current through collimating mirror and resonant cavity lens.

When laser passes through the airflow, one part of laser with specific wavelength induces microorganisms in the airflow to generate fluorescence and diverges to the concave light collecting lens, the other part of laser is reflected back and forth in the resonant cavity to continuously enhance optical signals, and finally the rest laser is transmitted through the second resonant cavity lens and directly irradiates into the blackbody to be absorbed, so that interference signals caused by reflection in the equipment are avoided. The fluorescence generated by sampling gas sucked by the air tap is collected and reflected by the concave light collecting lens to change the light path, light emitted by laser irradiation microorganisms is reflected to the grating sheet through the transmission lens, the grating sheet interferes and diffracts the light emitted by the laser irradiation microorganisms and sends the light to the signal analysis system to be converted into a first electric signal, the light emitted by the laser irradiation microorganisms is attenuated and absorbed by the transmission lens through the first optical filter and the second optical filter to avoid light intensity and other unnecessary light, the light is collected and focused in a photosensitive part at the lower part of the solid single photon detection chip through the light collecting lens, the photosensitive part converts the light signal into a second electric signal and sends the second electric signal to the solid single photon detection chip, the first electric signal is processed by the CCD image sensor to obtain microorganism types, the second electric signal is processed by the solid single photon detection chip to obtain microorganism particle size and microorganism number, the microorganism particle size and microorganism number are jointly displayed on the output equipment, and finally a user can know the microorganism types, the particle size and the microorganism number in the current environment in real time.

Compared with the prior art, the embodiment of the application provides the real-time microorganism particle counter with the following beneficial effects:

first, unnecessary optical components are removed, and only a few necessary components, 1 unnecessary component, and a housing are included without changing the power and other conditions of the laser transmitter 001. The optical path is optimized, and the optimized optical path has no mandatory requirements on the focal length and the size of the lens, so that the lens with the short focal length and the small size is selected as far as possible in the structural design, and the whole structural design is more compact.

Secondly, select single photon detector (SIPM) to design the singlechip as the basis, compare traditional scattered light detector has the advantage: high sensitivity, high time resolution, multiparameter detection, and miniaturized design. On the premise of ensuring the normal action of the light path, the detector can realize the rapid, accurate and real-time monitoring of the microorganism aerosol. In the working links of excitation, generation, reception and processing of the whole system, the resonant cavity structure is combined, so that the efficiency of the two links is greatly improved, the two links act together, the power of a laser and the requirement on the accuracy of an optical path are reduced, and the problem of error loss possibly caused by a simple optical path is solved on the premise of reducing the power of the laser by using the power, so that the working efficiency of the whole system is greatly improved.

Thirdly, two different optical signal receivers, namely an SIPM solid single photon detection chip and a CCD image sensor, are adopted, the two optical signal receivers can simultaneously analyze fluorescence spectra from two different angles of fluorescence intensity and fluorescence distribution, and the information of the quantity, concentration and the like of received photons is obtained through spectrum comparison, so that the different information of the types, particle size, quantity and the like of microorganisms can be obtained more intuitively and accurately, and a user can obtain the microorganism information in the gas to be detected more comprehensively and accurately.

In summary, the application is further optimized in terms of miniaturization, continuous workability, user visualization and high precision, so that the equipment can meet the practical production requirements.

The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.

Claims

1. A real-time microbial particle counter, the real-time microbial particle counter comprising: the system comprises an optical path system, an air path system and a signal analysis system;

2. The real-time microbial particle counter of claim 1, further comprising a blackbody for absorbing the laser light in the resonant cavity.

3. The real-time microbial particle counter of claim 1, wherein the number of filters is two for attenuating fluorescence emitted by the laser-irradiated microbes and absorbing the laser light present.

4. The real-time microbial particle counter of claim 1, further comprising an external air pump that sends a microbial-laden air stream from the air inlet air tap to the air outlet air tap.

5. The real-time microbial particle counter of claim 1, wherein the signal analysis system comprises a CCD image sensor for obtaining a microorganism type from the first electrical signal and a solid state single photon detection chip for obtaining a microorganism particle size and a microorganism number from the second electrical signal.

6. The real-time microbial particle counter of claim 5, wherein the solid state single photon detection chip comprises a single photon detector.

7. The real-time microbial particle counter of claim 1, further comprising a housing employing a combination of threaded washer and pin.

8. The real-time microbial particle counter according to claim 1, wherein the focal length of the collimating lens, the concave condensing lens and the condensing lens are each independently 8-10 mm.

9. The real-time microbial particle counter of claim 1, wherein a center of airflow between the air inlet air tap and the air outlet air tap is at a focal point of the collimating mirror.

10. The real-time microbial particle counter of claim 1, wherein the signal analysis system further comprises a light sensitive member located at a lower portion of the solid state single photon detection chip for converting photons in light emitted by the received laser-irradiated microbes into the second electrical signal.