Our Diesel Generators has high quality and smart
appearance, as well as low noise and fuel consumption, stable power
supplying ,easy to start and maintenance.
Diesel Generators Diesel Generators, Portable Diesel Generators, Diesel Generator Set, Diesel Power Generator Zhejiang Taizhou Wangye Power Co., Ltd , http://www.wyengine.com
Non-contact infrared radiation temperature measurement products include portable, online and scanning three series, and with a variety of optional accessories and corresponding computer software, each series in a variety of models and specifications. In various specifications of various types of thermometers, the correct selection of infrared thermometer model is very important for the user. Here only the thinking steps of how to correctly select the thermometer model are provided for the buyer's reference.
External thermometer working principle
Understanding the working principle, technical indicators, environmental working conditions, and operation and maintenance of the external thermometer is to help the user to select and use the infrared thermometer correctly.
All objects above absolute zero emit infrared radiation energy to the surrounding space. The infrared radiation characteristics of an object—the size of the radiation energy and its distribution by wavelength—are closely related to its surface temperature. Therefore, by measuring the infrared energy emitted by the object itself, the surface temperature of the object can be accurately measured. This is the objective basis on which the infrared radiation temperature measurement is based.
Black body radiation law:
Blackbody is an idealized radiator that absorbs all wavelengths of radiant energy, no energy is reflected and transmitted, and its surface has an emissivity of 1. It should be pointed out that there is no real black body in nature, but in order to understand and obtain the infrared radiation distribution law, a suitable model must be selected in theoretical research. This is Planck's quantum oscillator model of body cavity radiation, which is derived. Planck's law of blackbody radiation, which is the wavelength of the blackbody spectral irradiance, is the starting point of all infrared radiation theory, so called the blackbody radiation law.
Effect of object emissivity on radiation temperature measurement:
The actual objects that exist in nature are hardly black. The radiation amount of all actual objects depends on the wavelength of the radiation and the temperature of the object, and also relates to the types of materials constituting the object, the preparation method, the thermal process, and the surface conditions and environmental conditions. Therefore, in order for the law of blackbody radiation to apply to all real objects, a proportional coefficient, namely the emissivity, must be introduced in relation to the properties of the material and the surface state. The coefficient represents the degree of closeness of the thermal radiation of the actual object to blackbody radiation, with values ​​between zero and less than one. According to the law of radiation, as long as the emissivity of the material is known, the infrared radiation characteristics of any object are known.
The main factors affecting emissivity are:
Material type, surface roughness, physical and chemical structure and material thickness.
When measuring the target temperature with an infrared radiation thermometer, the infrared radiation amount of the target in its band is first measured, and then the temperature of the measured target is calculated by the thermometer. The monochromatic thermometer is proportional to the amount of radiation in the band: the two-color thermometer is proportional to the ratio of the radiation in both bands.
Infrared system:
Infrared thermometer consists of optical system, photodetector, signal amplifier, signal processing and display output. The optical system converges the target infrared radiation energy within its field of view. The size of the field of view is determined by the optical components of the pyrometer and its position. The infrared energy is focused on the photodetector and converted to a corresponding electrical signal. The signal passes through the amplifier and the signal processing circuit, and is converted into the temperature value of the measured target after being corrected according to the algorithm and target emissivity of the internal therapy of the instrument.
Select infrared thermometer can be divided into three aspects:
Performance indicators, such as temperature range, spot size, working wavelength, measurement accuracy, response time, etc.; environment and working conditions, such as ambient temperature, window, display and output, protection accessories, etc.; other options, such as ease of use, maintenance And calibration performance and price, etc., also have a certain influence on the choice of thermometer. With the development of technology and continuous development, the best design and new progress of infrared thermometers have provided users with various functions and multi-purpose instruments, which has expanded the choice.
Determine the temperature range:
The temperature measurement range is the most important performance indicator of the thermometer. For example, Raytek products range from -50°C to +3000°C, but this cannot be done with a model infrared thermometer. Each type of thermometer has its own specific temperature range. Therefore, the user's measured temperature range must be considered accurate and comprehensive, neither too narrow nor too wide. According to the law of black body radiation, the change of the radiant energy caused by temperature in the short wavelength band of the spectrum will exceed the change of the radiant energy caused by the emissivity error. Therefore, it is better to use short waves as much as possible when measuring temperature.
Determine the target size:
Infrared thermometer based on the principle can be divided into monochrome thermometer and two-color thermometer (radiometer colorimeter). For monochromatic thermometers, when measuring temperature, the measured target area should be full of thermometer field of view. It is recommended that the measured target size exceed 50% of the size of the field of view. If the target size is smaller than the field of view, background radiation energy will enter the thermometer's visual symbol and interfere with the temperature readings, causing errors. On the contrary, if the target is larger than the field of view of the thermometer, the thermometer will not be affected by the background outside the measurement area.
For dual-color thermometers, the temperature is determined by the ratio of the radiant energy in two separate wavelength bands. Therefore, when the target to be measured is small and there is no full scene, smoke and dust on the measurement path and the attenuation of radiation energy will not affect the measurement result. Even in the case of 95% energy reduction, the required accuracy of temperature measurement can still be guaranteed. Targets that are small and are in motion or in vibration; sometimes moving in the field of view, or may be partially out of the field of view. Under these conditions, using a two-color thermometer is the best choice. If it is impossible to aim directly between the pyrometer and the target, and the measurement channel is bent, narrow, and obstructed, the bicolor optical fiber pyrometer is the best choice. This is due to its small diameter, flexibility, and ability to transmit optical radiation energy in curved, blocked, and folded channels, and therefore can measure targets that are difficult to access, have harsh conditions, or are near an electromagnetic field.
Determine optical resolution (distance and sensitivity)
The optical resolution is determined by the ratio of D to S, which is the ratio of the distance D from the pyrometer to the target and the diameter S of the measurement spot. If the pyrometer must be installed far away from the target due to environmental conditions, but also to measure a small target, you should choose a high-resolution optical thermometer. The higher the optical resolution, ie the increase in the D:S ratio, the higher the cost of the pyrometer.
Determine the wavelength range:
The emissivity and surface properties of the target material determine the spectral response or wavelength of the pyrometer. For high reflectivity alloy materials, there are low or varying emissivities. In the high temperature area, the best wavelength for measuring metal materials is near infrared, and 0.18-1.0 μm wavelength can be selected. Other temperature zones are available with wavelengths of 1.6μm, 2.2μm and 3.9μm. Since some materials are transparent at a certain wavelength, infrared energy penetrates these materials, and special wavelengths should be selected for this material. Such as measuring the internal temperature of glass use 10μm, 2.2μm and 3.9μm (tested glass to be very thick, otherwise it will be through) wavelength; measuring the internal temperature of the glass using 5.0μm wavelength; low-zone selection of 8-14μm wavelength is appropriate; The wavelength of 3.43 μm is used for the measurement of polyethylene plastic film, and the wavelength of 4.3 μm or 7.9 μm is used for polyesters. Thickness of more than 0.4mm choose 8-14μm wavelength; Another example is to measure the flame in the C02 with a narrow band 4.24-4.3μm wavelength, measuring the flame in the C0 with a narrow band 4.64μm wavelength, measuring N02 flame with a wavelength of 4.47μm.
Determine response time:
The response time indicates the reaction speed of the infrared thermometer to the measured temperature change and is defined as the time required to reach 95% of the final reading. It is related to the time constant of the photodetector, the signal processing circuit and the display system. Bytek's new infrared thermometer has a response time of up to 1ms. This is much faster than contact temperature measurement. If the target's moving speed is fast or the target of rapid heating is measured, a fast-response infrared thermometer should be selected, otherwise, insufficient signal response can be achieved, which will reduce the measurement accuracy. However, not all applications require a fast-response infrared thermometer. When there is thermal inertia for a stationary or target thermal process, the response time of the thermometer can be relaxed. Therefore, the choice of response time of the infrared thermometer should be compatible with the situation of the target being measured.
Signal processing function:
Different from discrete processes (such as part production) and continuous processes, infrared thermometers are required to have signal processing functions (such as peak hold, valley hold, and average). When measuring the temperature of the glass on the conveyor belt, peak hold is used and the temperature output signal is sent to the controller.
Environmental conditions consider:
The environmental conditions in which the thermometer is located have a great influence on the measurement results and should be considered and properly addressed. Otherwise, the accuracy of the temperature measurement may even affect the damage of the thermometer. When the ambient temperature is too high, dust, smoke and steam are present, accessories such as protective covers, water cooling, air cooling systems, and air purifiers supplied by the manufacturer may be used. These accessories can effectively solve the environmental impact and protect the thermometer to achieve accurate temperature measurement. When determining attachments, standardized services should be required as much as possible to reduce installation costs. Dual-color thermometers are the best choice when smoke, dust or other particles lower the measured energy signal. Fiber optic dual-color thermometers are the best choice for noise, electromagnetic fields, vibration or inaccessible environmental conditions, or other harsh conditions.
In sealed or hazardous material applications (such as containers or vacuum boxes), the pyrometer observes through the window. The material must have sufficient strength and pass the operating wavelength range of the thermometer used. It is also necessary to determine whether the operator also needs to observe through the window, so choose the proper installation position and window material to avoid mutual influence. In cryogenic measurement applications, Ge or Si material is usually used as a window, not visible light, and the human eye cannot observe the target through the window. If the operator needs to pass through the window target, an optical material that transmits both infrared radiation and visible light should be used. For example, an optical material that transmits both infrared radiation and visible light, such as ZnSe or BaF2, should be used as a window material.
Simple operation, easy to use:
The infrared thermometer should be intuitive, easy to use, and easy to use by the operator. The portable infrared thermometer is a compact, lightweight, portable instrument that measures temperature and display output. The display panel can display temperature and output various temperature information, and some can be controlled by remote control or through a computer software program.
In the case of harsh and complex environmental conditions, it is possible to select a system in which the temperature measuring head and the display are separated to facilitate installation and configuration. The signal output form that matches the current control equipment can be selected.
Infrared radiation thermometer calibration:
The infrared thermometer must be calibrated so that it can accurately display the temperature of the target under test. If the thermometer used in the use of temperature measurement error occurs, you need to return to the manufacturer or repair center re-calibration.
A Diesel Generator is the combination of a Diesel Engine with an electrical generator (often an alternator) to generate electrical energy. Diesel generating sets are used in places without connection to the power grid, as emergency
power-supply if the grid fails, as well as for more complex applications
such as peak-lopping, grid support and export to the power grid. Sizing
of Diesel Generators is critical to avoid low-load or a shortage of
power and is complicated by modern electronics, specifically non-linear
loads.
Infrared temperature measurement technology is playing an important role in product quality control and monitoring, equipment online fault diagnosis, safety protection, and energy conservation. In the past two decades, non-contact infrared thermometers have been rapidly developed in technology, performance has been continuously improved, and the scope of application has also been continuously expanding. Market share has increased year by year. Compared with contact temperature measurement methods, infrared temperature measurement has the advantages of fast response time, non-contact, safe use, and long service life.