52results about How to "Low measurement limit" patented technology

The invention discloses a measuring device and a measuring method of light scattering particles. The measuring device successively comprises a divergent beam module, a measurement zone, a receiving lens, a multielement photodetector, a transmission light detector, a signal processing circuit, and an analog-to-digital converter. The method comprises the following steps that: particles in the measurement zone are illuminated by the divergent beam, the scattered light and transmission light are collected by the receiving lens simultaneously, the scattered light is projected on each detection unit of the multielement photodetector to obtain a scattered light distribution signal, the un-scattered part of the incident light is received by the transmission light detector to obtain a transmissionlight signal, the scattered light distribution signal and transmission light signal are amplified, collected and converted by the signal processing circuit and the analog-to-digital converter, and particle size distribution and concentration information are calculated according to the scattered light distribution signal and transmission light signal. According to the invention, the problem of signal interference caused by close distance between the measurement zone and the detector is solved, the lower limit of the particle measurement is lowered, and the invention can be applied in a plurality of areas of particle measurement.

The invention discloses a gas concentration measuring method based on spectral absorptivity second harmonics feature extraction. The method disclosed by the invention realizes calculation of integralabsorbance by virtue of harmonic characteristics by building a spectral absorptivity second harmonics peak height-peak width characteristic relation applicable to any modulation coefficient and considering a Voith line type, thus gas parameter information is obtained; meanwhile, in an implementation process of the method, a logarithm processing technology is adopted, influence of residual amplitude modulation on harmonic signal distortion is directly eliminated, and measurement accuracy is improved; the measuring method disclosed by the invention does not need to perform complex least-squaresiteration fitting calculation and only needs to perform filtering processing once, thus requirements on a hardware system are reduced; information of feature points of a waveform still can be relatively accurately extracted when a complete harmonic signal can not be obtained, and a lower measurement limit is lower; and excessive parameters such as a self-broadening coefficient, collision broadening coefficients of various other components and a temperature-dependent index in a database do not need to be utilized, dependence on database parameters is reduced, and application range is wider.

The method of detecting multiple heavy metal elements simultaneously is one combined ion selecting electrode and leaching voltage-current method. In the detecting system, the electrode combination of several selecting electrodes, reference electrodes and working electrodes is adopted. For practical solution with several kinds of heavy metal elements in wide dynamic content range, the selecting ion electrodes are first used to detect heavy metals in high content, and leaching voltage-current method is then adopted. The present invention has simple sample processing program, is suitable for automatic measurement, and may be used in various fields.

The invention relates to a broadband fluorescence spectrum strain sensing method. The method comprises steps that, a broadband spectrum of a fluorescent material is utilized to carry out for strain measurement, intensity integration and spectrum band medium division processing on fluorescence spectrum band data in wave number distribution are sequentially carried out to acquire a gravity center wave number value of the fluorescence spectrum band, the gravity center wave number value is taken as the position of the spectrum band, and thereby a sensing function relation between the spectrum band gravity center and strain is acquired. Through the method, physical meaning of the spectrum band gravity center is explained, strain measurement feasibility through the spectrum band gravity center method is approved through examples, and stress magnitude can be reckoned according to a strain value and a material mechanical strength value.

The invention discloses an electromagnetic jet flow flowmeter. It discloses a resist flow piece installs in the measuring tube of the jet flow flowmeter and a U type electromagnetism structure installs on the measuring tube, the first electrode, the second electrode, the third electrode installs on the measuring tube and resist flow side of the inferior of the U type electromagnetism structure. The U electromagnetism structure is composed by pair of permanent magnet and an exciting coil, controls by monolithic integrated circuit to strengthen or weaken the measuring tube magnetic field. The second electrode connects the grounding of the difference enlarge electric circuit by the wire, the first electrode, the third electrode connect the difference enlarge electric circuit input end by the wire, the difference enlarge electric circuit out-port connect the comparator electric circuit, the monolithic integrated circuit electric circuit in turn. The monolithic integrated circuit electric circuit also provides LCD monitor, pressed key input and so on electric circuit. The entire electric circuit uses a battery power supply. The merit of jet flow flowmeter is that the low power loss, the wide measuring range, the high exempt maintenance, reliable, high accuracy and so on.

The invention provides a monitoring device and a monitoring method for ultralow emission smoke. The monitoring device is used for monitoring particle size distribution and concentration of smoke in a smoke measuring area. The monitoring device comprises a multi-wavelength laser light source part and a multi-angle photoelectric detection part, wherein the multi-wavelength laser light source part comprises a plurality of laser devices, a coupler and a collimator; the laser devices are used for emitting the laser light in different wavelengths; the coupler is used for coupling the laser light in different wavelengths; the collimator is used for collimating the laser light after being coupled and acquiring the multi-wavelength laser light used for irradiating the smoke measuring area; the multi-angle photoelectric detection part comprises a plurality of photoelectric detectors, a signal modulator and a signal processor; the photoelectric detectors are respectively arranged at certain angles with the collimator and are used for distinguishing the strength of laser light with different wavelengths, receiving the multi-wavelength laser light after smoke particle scattering and converting into an electric signal; the signal modulator is used for receiving the electric signal and modulating; the signal processor is used for processing the electric signal after being modulated, so as to acquire the particle size and concentration of the smoke.

A large-caliber vortex follow meter comprises a large-caliber measuring tube and a small-caliber magneto-electric vortex follow meter, which is characterized in that the small-caliber magneto-electric vortex follow meter is inserted in the large-caliber measuring tube, wherein the caliber of the large-caliber measuring tube can be up to DN600, even be much larger. Compared with an original vortex follow meter under the same caliber and the same flow velocity, the invention can release higher frequency and stronger signals, namely that the novel flow meter has the advantages of high measuring precision, low measuring lower limit and short length of straight tube sections installed back and forth. And the core portion of a small-caliber sensor can return the factory or the monitoring management office at the premise that measuring tubes with the same specification are ensured to exchange (the measuring tube for the detection is consistent with user measuring pipes) under the condition of guaranteeing the installation direction of the small-caliber sensor consistent, and the problem that the magneto-electric vortex follow meter is difficult to deliver to be detected is solved, and the installation and detachment costs in detection is greatly reduced.

The invention discloses a piezoelectric fluidic heat meter, in particular to a fluidic heat meter made of engineering plastic polyphenylene oxide (PPO). A flow choking part is installed in a measuring tube of the fluidic heat meter, two piezoelectric sensors are installed in feedback channels at both sides of the measuring tube and are connected to the input end of a differential amplification circuit, and the output end of the differential amplification circuit is sequentially connected to a comparator circuit and a singlechip circuit. The microcontroller circuit also provides circuits, such as an LCD display circuit, an infrared communication circuit, a temperature measurement circuit, and the like. A whole circuit uses one battery to supply power. The fluidic heat meter has the advantages of low power consumption, wide measuring range, free maintenance, high reliability, high accuracy, and the like.

The invention discloses a weak signal extraction system for a fluidic flowmeter based on a related amplification technology and a method. The system adopts the related amplification technology as a signal processing mode of the fluidic flowmeter. A flow choking part is installed in a measuring tube; a first electrode, a third electrode and a second electrode are respectively installed at the front side and the back side of the flow choking part; a U-shaped excitation structure is installed on the measuring tube and can carry out excitation control by being connected with an excitation drive circuit; the second electrode is connected with the ground end of a related amplification circuit through a wire; the first electrode and the third electrode are connected to a differential amplification input end of the related amplification circuit; the output end of the related amplification circuit is respectively connected with an AD conversion circuit and a singlechip circuit, and the AD conversion circuit is connected to the singlechip circuit; and the singlechip circuit also fulfills the functions of LCD display and the like. By adopting the method, the fluidic flowmeter has the advantages of lower limit, wide measurement range, high accuracy, and the like.

The invention discloses a device and method for measuring the gas pressure and components of the cavity of an extremely-small sealing device. With the device and method of the invention adopted, the measurement of the gas pressure and component content of the cavity of an extremely-small sealing device of which the gas sealing device inner cavity volume ranges from 0.005-0.1 cm <3> can be realized. The method of the invention is a measurement method combining static expansion and dynamic flow mass spectrometry. With a double-small-hole structure adopted, not only can a gas sampling quality discrimination effect be overcome, but also the pressure stability of a pressure measurement cavity and a component measurement cavity can be ensured. According to an existing method, problems exist, in a measurement process, that the pressure attenuation of the cavity of a measured sealing device is fast, mass spectrometry time sequence response is slow, and the accurate measurement of the gas components of a product of which the sealing device inner cavity volume is very small cannot be achieved. With the device and method of the invention adopted, the problems in the prior art can be solved.

The invention discloses a large-caliber magnetoelectric vortex shedding flowmeter which comprises a large-caliber sounding pipe and a small-caliber magnetoelectric vortex shedding flowmeter and is characterized in that the small-caliber magnetoelectric vortex shedding flowmeter is inserted into the large-caliber sounding pipe. The caliber of the large-caliber magnetoelectric vortex shedding flowmeter of the invention can achieve DN600 at most, even larger. Under the situation of the same caliber and flow speed, compared with the original magnetoelectric vortex shedding flowmeter, the flowmeter of the invention can release with high frequency and strong signals, that is, the novel flowmeter has the advantages of high measuring accuracy, low measurement lower limit, and short straight pipe sections installed at the front and the back; under the premise of guaranteeing the sounding pipes with the same specification are interchangeable (guaranteeing that the sounding pipe used for detection and the sounding pipe of a user are consistent), and under the situation of keeping the direction of installing the small-caliber sensor to be consistent, the core part of the small-caliber sensor is returned to the OEM or the monitoring and managing department, thus solving the problem of the difficult sending for detection of the large-caliber magnetoelectric vortex shedding flowmeter and greatly reducing the assembly and disassembly cost of the sending for detection.

The invention discloses a photoelectric sensing system applied to rotation speed measurement. The system comprises a photoelectric sensor, a motor to be measured, a power supply module and a supporting base; the power supply module is in bidirectional connection with the photoelectric sensor, a display unit and the motor to be measured through wires; and the photoelectric sensor is in bidirectional connection with the display unit through a wireless transmit-receive module. The invention belongs to the technical field of rotation speed measurement. According to the photoelectric sensing systemapplied to the rotation speed measurement, the optical fiber sensor is adopted as a measuring main body; the short testing time of the optical fiber sensor is short; and the optical fiber sensor doesnot need to be in direct contact with the object to be measured, and has high stability. The test time of an existing optical sensor is long; if the existing optical sensor is used for rotation speedmeasurement, the measurement limit of the existing optical sensor is low; the existing optical sensor is only applicable to some motors, and fails to realize measurement for some special motors; andexisting optical sensing equipment has low stability and needs to be in actual physical contact with a object to be measured during measurement, and as a result, measurement deviation will be broughtabout easily. With the photoelectric sensing system of the invention adopted, the above problems can be solved.

The invention belongs to the technical field of weak current measurement, and particularly relates to a low leakage current resetting device applied to a capacitive integrating weak current measuringcircuit. The resetting device is connected with a capacitance integrating weak current measuring circuit (2) used for measuring weak current to be measured (1). The resetting device comprises a resetcurrent circuit (3), a multiplexer (4), a D/A converter (5), a voltage follower (6) and a logic control unit (7). The voltage follower (6) can copy the voltage of the weak current to be measured (1) as the turn-off voltage of the reset current circuit (3). The D/A converter (5) can provide turn-on voltage with adjustable polarity and magnitude for the reset current circuit (3). The resetting device further comprises a logic control unit (7) which controls the multiplexer (4) to select to output turn-off voltage or turn-on voltage, and controls the polarity and magnitude of the turn-on voltageoutput by the D/A converter (5). According to the invention, the measurement lower limit and the minimum resolution of the capacitive integrating weak current measuring circuit system can be greatly improved.

The invention discloses an ultrahigh-spectral transmittance etalon, which comprises a fixed part and light filters, wherein the light filters are of a sector structure, are alternately arranged on thefixed part and are used for filtering or shielding continuous light emitted from a light source. The upper limit of measurement of the transmittance is improved or the lower limit of measurement of the transmittance is reduced through alternately arranging at least one light filter with fixed transmittance on the fixed part and setting the sector area/central angle ratios of the light filters, the measurement range of the spectral transmittance etalon is greatly improved, meanwhile, the measurement uncertainty on the transmittance is greatly reduced, the spectral flatness of a transmittance curve is improved and the measurement uniformity on the transmittance is improved.

The invention discloses an intrinsic safety type vortex street flow sensor for oiling machine gas phase recovery measurement. The intrinsic safety type vortex street flow sensor comprises a sensor body and a safety barrier with an explosion-proof function. The sensor body comprises a shell; the circulation cavities in the inlet end and the outlet end are both of a structure which is gradually necked down from outside to inside; a piezo-electric crystal is arranged at the top of the circulation cavity in the middle of the shell, and a vertically-arranged turbulence column is arranged in the circulation cavity between the piezo-electric crystal and the inlet end; the shell provided with the turbulent flow column, the inlet end and the outlet end is of an integrally formed structure; the piezo-electric crystal is electrically connected with a filtering and amplifying circuit arranged on the circuit board; and a top cover is arranged on the shell at the upper part of the circuit board. After the gas phase entering the device passes through the turbulent flow column, Karman vortexes are formed at the circulation cavity at the lower part of the piezoelectric crystal, and weak pulse charge signals formed by the Karman vortexes are detected through the high-sensitivity piezoelectric crystal so that the detection of gas phase flow is realized, and the sensitivity is high and the reaction speed is high.

The invention proposes a method and device for measuring the speed of fluid inside of the container or pipe. The invention uses pitot tube as the testing device of total pressure and the static pressure, uses scale pressure testing double-tube as the testing device of pressure difference, uses the reading mricoscope as the reading device of water head in the testing tube.

The invention relates to the technical field of environmental monitoring, in particular to a parallel air pollutant detection device based on mass spectrometry and a method for detecting air pollutants by using the same. The device comprises a mass spectrometer, an air distribution device, a carrier gas balancing device and a plurality of gas exchange devices. The air distribution device and the carrier gas balancing device respectively distribute the detected air and the carrier gas, and the air enters each gas exchange device for gas exchange, so that the gas exchange efficiency is improved.And compared with a single gas exchange device, the equipment space is greatly saved, the accuracy of mass spectrum detection is not influenced, and the detection limit is low.