In response to the testing and R&D requirements of electronic components such as semiconductors and automotive electronics, Lab Companion has developed a smaller capacity small rapid temperature change (wet heat) test chamber. While maintaining the advantages of standard rapid temperature change test chambers, it can also meet the needs of customers who have requirements for space size, with a single-phase 220VAC voltage specification. It can also meet the equipment usage requirements of customers in civilian office areas such as research institutions and universities.
Its main features are as follows:
1. It has powerful heating and cooling performance
2. Heating rate: 15℃/min; Cooling rate: 15℃/min
3. (Temperature range: -45℃ to +155℃)
4. Single-phase 220VAC, meeting the electricity demands of more customers
5. Single-phase 220VAC, suitable for industrial and civil power supply specifications, can meet the equipment power demands of customers in civil office areas such as research institutions and universities.
6. The body is small and exquisite, with a compact structure and easy to move
7. The miniaturized structure design of the test chamber can effectively save configuration space.
8. The inner tank volume is 100L, the width is 600mm, the depth is less than 1400mm, and the product volume is less than 1.1m ³. It is suitable for the vast majority of residential and commercial elevators in China (GB/T7025.1).
9. The standard universal wheels enable the product to move freely at the installation site.
10. Standard air-cooled specification is provided, facilitating the movement and installation of the product
11. At the same time, it saves customers the cost and space of configuring cooling towers.
12. A more ergonomic operation touch screen design
13. Through the multi-angle adjustment of the touch screen, it can meet the operation needs and provide the best field of vision for users of different heights, making it more convenient and comfortable.
14. Energy-saving cold output temperature and humidity control system, with dual PID and water vapor partial pressure control, features mature technology and extremely high precision.
15. Network control and data acquisition can be carried out through the interface (RS-485/GPIB/Web Lan/RS-232C).
16. It is standard-equipped with left and right cable holes (50mm), which facilitates the connection of power on the sample and the conduct of multiple measurements.
17. The controller adopts a color LCD touch screen, which is simple and convenient to operate
18. Through the controller, two control methods, fixed value and program, can be selected to adapt to different applications.
19. The program control can be set to 100 modes, with 99 steps for each mode. Repeat the loop up to 999 times.
20. Multiple languages can be easily switched (Simplified Chinese, English), and test data can be stored on a USB flash drive.
When conducting low-temperature tests in a temperature test chamber, preventing condensation is a crucial and common issue. Condensation not only affects the accuracy of test results, but may also cause irreversible damage to products, such as short circuits, metal corrosion, and degradation of material performance.
The essence of condensation is that when the surface temperature of the product drops below the "dew point temperature" of the ambient air, water vapor in the air condenses into liquid water on the product surface. Based on this principle, the core idea for preventing condensation is to avoid the surface temperature of the product being lower than the dew point temperature of the ambient air. The specific methods are as follows:
Controlling the rate of temperature change is the most commonly used and effective method. By slowing down the rate of cooling or heating, the temperature of the product can keep up with the changes in ambient temperature, thereby reducing the temperature difference between the two and preventing the surface temperature of the product from falling below the dew point.
2. Use dry air or nitrogen to directly reduce the absolute humidity of the air inside the test chamber, thereby significantly lowering the dew point temperature. Even if the surface of the product is very cold, as long as the dew point of the ambient air is lower, condensation will not occur. It is usually used for products that are extremely sensitive to moisture, such as precision circuit boards and aerospace components, etc.
3. Local heating or insulation can ensure that the surface temperature of key components (such as circuit boards and sensors) is always above the dew point, which is more suitable for products with complex structures where only certain areas are sensitive to humidity.
4. Skillfully arrange the temperature cycle through programming to avoid exposing the product at the stage when condensation is most likely to occur. After the test is completed, do not directly open the box door in a normal temperature and humidity environment. Dry gas should first be introduced into the box and the temperature should be slowly raised to room temperature. After the product temperature has also risen, the box can be opened and taken out.
For a typical low-temperature test, the following process can be followed to prevent condensation to the greatest extent
First, place the product and the test chamber in a standard laboratory environment for a sufficient period of time to stabilize their condition. Subsequently, within the range close to room temperature to "0°", set up one or more short-term insulation platforms. Or maintain it at the target low temperature for a sufficient period of time, during which the temperature inside and outside the product is consistent, and usually no new condensation will form. Also, set a heating rate that is slower than the cooling rate. Set up an insulation platform at the initial stage of temperature rise and when approaching the ambient temperature. After the temperature rise is completed, do not open the door immediately. Keep the box door closed and let the product stand in the box for "30 minutes to 2 hours" (depending on the heat capacity of the product), or introduce dry air into the box to accelerate the equalization process. After confirming that the product temperature is close to the ambient temperature, open the box door and take out the product.
The best practice is to use the above methods in combination. For instance, in most cases, "controlling the temperature variation rate" combined with "optimizing the test program (especially during the recovery stage)" can solve 90% of the condensation problems. For military or automotive electronics tests with strict requirements, it may be necessary to simultaneously stipulate the temperature variation rate and require the introduction of dry air.
Polypropylene (PP) itself is a highly flammable hydrocarbon with a limiting oxygen index (LOI) of only 17.8%. It will continue to burn even after being removed from the fire source. The core principle of flame-retardant PP is to interrupt or delay its combustion cycle through physical and chemical means. Combustion requires the simultaneous existence of three elements: combustible material, heat and oxygen. The function of flame retardants is to destroy this "burning triangle".
In industry, flame retardancy is mainly achieved by adding flame retardants to PP. Different types of flame retardants function through the following mechanisms:
1. Gas-phase flame retardant mechanism
This is one of the most common mechanisms, especially applicable to traditional halogen-based flame retardants. When flame retardants are heated and decomposed, they can capture the free radicals (such as H· and HO·) that maintain the combustion chain reaction in the combustion reaction zone (flame), causing their concentrations to drop sharply and thus interrupting the combustion.
2. Condensed phase flame retardant mechanism
This is the most mainstream mechanism of halogen-free flame-retardant PP. Flame retardants promote the formation of a uniform and dense carbon layer on the surface of polymers. This layer of carbon has three major functions. The first step is to prevent external heat from entering the interior of the polymer. Secondly, it prevents the escape of flammable gases inside and the entry of external oxygen. Finally, it inhibits the further pyrolysis of the polymer and the generation of smoke.
When a fire occurs, the acid source promotes the dehydration, cross-linking and carbonization of the carbon source. Meanwhile, the large amount of gas produced by the decomposition of the gas source causes the softened carbon layer to expand, eventually forming a porous, dense and strong foam carbon layer, which protects the underlying PP like "armor".
3. Cooling/heat absorption mechanism
Flame retardants absorb a large amount of heat during the decomposition process, reducing the surface temperature of polymers and making it difficult for them to continuously pyrolyze and produce flammable gases. Typical representatives include aluminium hydroxide (ATH) and magnesium hydroxide (MH). When they decompose, they absorb a large amount of heat (endothermic reaction) and release water vapor. The water vapor can not only dilute flammable gases but also play a cooling role.
4. Dilution mechanism
Flame retardants decompose to produce a large amount of non-flammable gases (such as water vapor and CO₂, etc.), which can dilute the concentration of flammable gases and oxygen near the polymer surface, making combustion unsustainable. Both the gas sources of metal hydroxides and intumescent flame retardants have this function.
In conclusion, the working principle of flame-retardant PP in industry is a complex process involving the synergy of multiple mechanisms. Modern flame-retardant PP technology is developing towards halogen-free, low smoke, low toxicity and high efficiency. Among them, the condensed phase flame-retardant mechanism represented by intumescent flame retardants (IFR) is the core of current research and application. By carefully designing flame-retardant formulas, the best balance can be achieved among flame-retardant efficiency, material mechanical properties, processing performance and cost.
The core of the thermal resistance induction in high and low temperature test chambers also utilizes the physical property that the resistance value of platinum metal changes with temperature. The core logic of the control system is a closed-loop feedback control: measurement → comparison → regulation → stability
Firstly, the thermal resistance sensor senses the current temperature inside the chamber and converts it into a resistance value. The measurement circuit then converts the resistance value into a temperature signal and transmits it to the controller of the test chamber. The controller compares this measured temperature with the target temperature set by the user and calculates the deviation value. Subsequently, the controller outputs instructions to the actuator (such as the heater, compressor, liquid nitrogen valve, etc.) based on the magnitude and direction of the deviation. If the measured temperature is lower than the target temperature, start the heater to heat up; otherwise, start the refrigeration system to cool down. Through such continuous measurement, comparison and adjustment, the temperature inside the box is eventually stabilized at the target temperature set by the user and the required accuracy is maintained.
Due to the fact that high and low temperature test chambers need to simulate extreme and rapidly changing temperature environments (such as cycles from -70°C to +150°C), the requirements for thermal resistance sensors are much higher than those for ordinary industrial temperature measurement.
Meanwhile, there is usually more than one sensor inside the high and low temperature test chamber.
The main control sensor is usually installed in the working space of the test chamber, close to the air outlet or at a representative position. It is the core of temperature control. The controller decides on heating or cooling based on its readings to ensure that the temperature in the working area meets the requirements of the test program.
The monitoring sensors may be installed at other positions inside the box to verify with the main control sensors, thereby enhancing the reliability of the system.
Over-temperature protection is independent of the main control system. When the main control system fails and the temperature exceeds the safety upper limit (or lower limit), the monitoring sensor will trigger an independent over-temperature protection circuit, immediately cutting off the heating (or cooling) power supply to protect the test samples and equipment safety. This is a crucial safety function.
Lab thermal resistance sensor is a precision component that integrates high-precision measurement, robust packaging, and system safety monitoring. It serves as the foundation and "sensory organ" for the entire test chamber to achieve precise and reliable temperature field control.
Standar Uji Suhu Tinggi dan Rendah Bahan Plastik PC1. Uji suhu tinggi Setelah ditempatkan pada suhu 80±2℃ selama 4 jam dan pada suhu normal selama 2 jam, dimensi, resistansi isolasi, resistansi tegangan, fungsi tombol, dan resistansi loop memenuhi persyaratan normal, dan tidak ada fenomena abnormal seperti deformasi, lengkungan, dan pengelupasan pada tampilan. Titik cembung tombol runtuh pada suhu tinggi dan gaya tekan menjadi lebih kecil tanpa penilaian.2. Uji suhu rendahSetelah ditempatkan pada suhu -30±2℃ selama 4 jam dan pada suhu normal selama 2 jam, dimensi, resistansi isolasi, resistansi tegangan, fungsi kunci, dan resistansi loop memenuhi persyaratan normal, dan tidak ada fenomena abnormal seperti deformasi, lengkungan, dan pengelupasan pada tampilan.3. Uji siklus suhuMasukkan ke dalam lingkungan 70±2℃ selama 30 menit, keluarkan pada suhu ruangan selama 5 menit; Biarkan di lingkungan -20±2℃ selama 30 menit, keluarkan dan biarkan pada suhu ruangan selama 5 menit. Setelah 5 siklus tersebut, dimensi, resistansi isolasi, resistansi tegangan, fungsi kunci, resistansi sirkuit memenuhi persyaratan normal, dan tidak ada deformasi, lengkungan, pengelupasan, dan fenomena abnormal lainnya. Titik cembung kunci runtuh pada suhu tinggi dan gaya tekan menjadi lebih kecil tanpa penilaian.4. Tahan panasSetelah ditempatkan di lingkungan dengan suhu 40±2℃ dan kelembaban relatif 93±2%rh selama 48 jam, dimensi, resistansi isolasi, resistansi tegangan, fungsi tombol, dan resistansi loop memenuhi persyaratan normal, dan tampilannya tidak berubah bentuk, melengkung, atau terkelupas. Titik cembung tombol akan runtuh pada suhu tinggi dan gaya tekan akan menjadi lebih kecil tanpa penilaian.Nilai standar nasional untuk pengujian plastik:Gb1033-86 Metode pengujian kepadatan plastik dan kepadatan relatifGbl636-79 Metode pengujian kepadatan nyata plastik cetakanGB/ T7155.1-87 Penentuan kepadatan pipa dan alat kelengkapan pipa termoplastik bagian: penentuan kepadatan referensi pipa dan alat kelengkapan pipa polietilenGB/ T7155.2-87 Pipa dan fitting termoplastik -- Penentuan kepadatan -- Bagian L: Penentuan kepadatan pipa dan fitting polipropilenaGB/T1039-92 Aturan umum untuk menguji sifat mekanik plastikGB/ T14234-93 Kekasaran permukaan bagian plastikMetode uji kilap cermin plastik Gb8807-88Metode pengujian sifat tarik film plastik GBL3022-9LGB/ TL040-92 Metode pengujian sifat tarik plastikMetode pengujian sifat tarik pipa termoplastik GB/T8804.1-88 pipa polivinil kloridaGB/ T8804.2-88 Metode pengujian sifat tarik pipa termoplastik Pipa polietilenMetode uji perpanjangan suhu rendah plastik Hg2-163-65GB/ T5471-85 Metode untuk menyiapkan spesimen cetakan thermosettingMetode persiapan sampel termoplastik HG/T2-1122-77GB/ T9352-88 persiapan sampel kompresi termoplastikwww.oven.cclabcompanion.cn Lab Companion Tiongkoklabcompanion.com.cn Lab Companion Tiongkoklab-companion.com Lab Companion labcompanion.com.hk Lab Companion Hong Konglabcompanion.hk Lab Companion Hong Konglabcompanion.de Lab Companion Jerman labcompanion.it Lab Companion Italia labcompanion.es Lab Companion Spanyol labcompanion.com.mx Lab Companion Meksiko labcompanion.uk Lab Companion Inggris Rayalabcompanion.ru Lab Companion Rusia labcompanion.jp Lab Companion Jepang labcompanion.in Lab Companion India labcompanion.fr Lab Companion Prancislabcompanion.kr Lab Companion Korea
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