According to different characteristics, such as function, detection and control object, structure, principle, etc. All kinds of instruments and meters are divided into several small classes or classes. Industrial automation instruments are divided into detection instruments, display instruments, adjustment instruments and actuators according to their functions. Among them, measuring instruments are divided into temperature measuring instruments, pressure measuring instruments, flow measuring instruments, liquid level measuring instruments and mechanical measuring instruments according to the measured physical quantities. Temperature measuring instrument and mechanical quantity measuring instrument. Temperature measuring instruments are divided into contact temperature measuring instruments and non-contact temperature measuring instruments according to measuring methods. Contact thermometers are divided into thermoelectric type, expansion type and electric cathode type. The classification of other instruments and meters is similar, mainly related to the development process, usage habits and classification of related products. There is no uniform standard for converting instruments into steel, and there is a similar situation in the naming of instruments.
Shared species
As a basic and important category of analytical instruments, chromatographic instruments have a wide range of applications and a high penetration rate, which has always been one of the focuses of analytical instrument users and manufacturers.
Environmental monitoring instruments are the general name of instruments specially used to monitor indoor and outdoor environmental parameters. By measuring the representative values of factors affecting environmental quality, the environmental quality or pollution degree and its changing trend are determined.
Molecular spectrometer, including ultraviolet visible, molecular fluorescence, Raman spectrum, infrared spectrum, spectral imaging technology, etc. , is a commonly used analytical tool in the laboratory. With the progress of hardware and software technology, molecular spectroscopy instrument technology is constantly improving, and has become an effective means to solve various technical problems of molecular analysis. Its application fields are also expanding, especially in food safety, drug detection and life sciences, and various on-site rapid analysis.
The development trend of molecular spectroscopy instrument technology is mainly miniaturization and increasing its stability, from laboratory analysis to on-site detection; It is also an important development direction of molecular spectroscopy to study analytical methods and broaden application fields. In addition to technological progress, the requirement of simple and convenient operation has also brought the intelligent development of the instrument, and the addition of large-size color touch screen and tablet computer has also increased the user's operating experience.
Electrochemical analysis is an important part of instrumental analysis, which, together with spectral analysis and chromatographic analysis, constitutes three important pillars of modern analytical instruments. Electrochemical analysis has high sensitivity, accuracy and selectivity. Electrochemical instruments and devices are relatively simple, easy to operate and widely used.
Electrochemical analysis is rich in content, and a relatively perfect theoretical system has been established in recent years. It is widely used in modern chemical industry, biological and pharmaceutical analysis, environmental analysis and other fields, especially in the field of life science, and plays an irreplaceable role in other analytical methods. With the rapid development of environmental monitoring, biomedicine and other fields, the demand for electrochemical instruments is increasing.
Commonly used laboratory equipment mainly involves sample pretreatment, laboratory furniture, providing the environment needed for synthesis/reaction and providing the consumables needed for the laboratory.
Gas thermometer: Hydrogen or helium is often used as temperature measuring material, because the liquefaction temperature of hydrogen and helium is very low, close to absolute zero, so its temperature measuring range is very wide. This kind of thermometer has high accuracy and is mostly used for precise measurement.
Resistance thermometer: divided into metal resistance thermometer and semiconductor resistance thermometer, both of which are made according to the characteristics of resistance changing with temperature. Metal thermometers are mainly made of pure metals such as platinum, gold, copper and nickel and alloys of rhodium, iron and phosphor bronze. Semiconductor thermometers mainly use carbon and germanium. Resistance thermometer is convenient and reliable to use, and has been widely used. The measuring range is about -260℃ to 600℃. ?
Thermocouple thermometer: It is a kind of temperature measuring instrument widely used in industry. Composed of thermoelectric phenomena. Two different metal wires are welded together to form a working end, and the other two ends are connected with a measuring instrument to form a circuit. When the working end is placed at the temperature to be measured, when the temperatures of the working end and the free end are different, electromotive force will appear, so there is current in the circuit. By measuring the electric quantity, we can use the temperature of a known place to measure the temperature of another place. This thermometer consists of copper-constantan, iron-constantan, nickel-constantan, gold-cobalt-copper, platinum-rhodium and so on. It is suitable for measuring high temperature and low turbidity between two substances with large temperature difference. Some thermocouples can measure high temperatures as high as 3000℃, while others can measure low temperatures close to absolute zero. ?
High temperature thermometer: refers to the thermometer specially used to measure the temperature above 500℃, including optical thermometer, colorimetric thermometer and radiation thermometer. The principle and structure of high temperature thermometer are complicated, so I won't discuss it here. Its measuring range is above 500℃ to 3000℃, so it is not suitable for measuring low temperature.
Pointer thermometer: It is a thermometer that looks like a dashboard, also called thermometer. It is used to measure room temperature, and is made according to the principle that metal expands when heated and contracts when cooled. It uses bimetal as a temperature sensing element to control the pointer. Bimetal sheets are usually riveted together with copper sheets and iron sheets, with copper sheets on the left and iron sheets on the right. Because the thermal expansion and contraction of copper is much more obvious than that of iron, when the temperature rises, the copper sheet pulls the iron sheet to bend to the right, and the pointer deflects to the right (pointing to high temperature) driven by bimetal; On the contrary, when the temperature becomes low, the pointer deflects to the left (pointing to low temperature) driven by bimetal.
Glass tube thermometer: Glass tube thermometer uses the principle of thermal expansion and contraction to measure temperature. Because the expansion coefficient of temperature measuring medium is different from boiling point and freezing point, our common glass tube thermometers mainly include kerosene thermometer, mercury thermometer and red pen water thermometer. Its advantages are simple structure, convenient use, high measurement accuracy and low price. The disadvantage is that the upper and lower limits and accuracy of measurement are limited by the quality of glass and the properties of temperature measuring medium. And can't spread very far, fragile.
Pressure thermometer: A pressure thermometer uses the volume expansion or pressure change of liquid, gas or saturated steam in a closed container after being heated as a measuring signal. Its basic structure consists of three parts: temperature bag, capillary and indicator. It is one of the earliest methods applied to temperature control in production process. Pressure temperature measurement system is still a widely used measurement method to indicate and control temperature on site. The advantages of pressure thermometer are simple structure, high mechanical strength and no fear of vibration. The price is low and no external energy is needed. Disadvantages are: the temperature measuring range is limited, generally at-80 ~ 400℃; Large heat loss and slow response time; The instrument sealing system (bulb, capillary tube and spring tube) is difficult to maintain and must be replaced; The measurement accuracy is greatly influenced by the ambient temperature and the installation position of the heat pack, and the accuracy is low; Capillary transmission distance is limited.
Thermocouple thermometer: Thermocouple thermometer is made of two different metals connected to a sensitive voltmeter. Metal contacts will produce different potential differences at both ends of the metal at different temperatures. The potential difference is so small that a sensitive voltmeter is needed to measure it. We can know what the temperature is from the reading of the voltmeter.
Liquid crystal thermometer: Liquid crystals made of different formulations have different phase transition temperatures, and their optical properties will also change during phase transition, making the liquid crystals look discolored. If liquid crystals with different phase transition temperatures are coated on a piece of paper, the temperature can be known from the change of liquid crystal color. The advantage of this thermometer is that it is easy to read, but the disadvantage is that it is not accurate enough. Often used to watch fish tanks, indicating water temperature.
Experimental instruments: multimeter, desktop multimeter, pointer instrument, oscilloscope, signal generator, LCR bridge, frequency meter, withstand voltage tester, desktop insulation resistance tester, desktop leakage current tester, desktop grounding resistance tester, power supply, electrical parameter tester, audio and video tester, digital equipment tester, distorter, electrostatic discharge tester, automatic component analyzer, coil number tester and transformer automatic test system;
Thermal instruments: infrared thermometer, infrared thermal imager, contact thermometer, temperature and humidity tester, online infrared thermometer and online infrared thermal imager;
Environmental protection instruments: noise measuring instrument, wind speed tester, toxic gas tester, halogen gas tester, smoke analyzer, temperature and humidity meter, airtight leak detector, gas detector and illuminance meter;
Optical communication measuring instruments: spectrum analyzer, optical time domain reflectometer, optical fiber docking device, optical fiber visual fault locator, optical fiber welding machine, optical fiber cutting machine, light source, optical power meter, optical fiber multimeter, optical return loss tester and error tester;
Non-destructive testing instruments: tachometer, vibrometer, ultrasonic coating thickness gauge, rangefinder, hardness tester, roughness gauge, ultrasonic flaw detector, laser caliper, coating thickness gauge, hand-held alloy analyzer, metal equipment defect diagnostic instrument, portable cable flaw detector, radar velocimeter, anticorrosive coating condition detector and electric spark tester;
Power instruments: clamp meter, megger, leakage current clamp meter, clamp grounding resistance tester, high-voltage insulation resistance tester, cable altimeter, grounding resistance tester, power factor meter, non-contact phase detector for power, leakage switch tester, loop impedance tester, power comprehensive tester, line tracker and power quality analyzer.