The Measuring Principle of Hygrometer in High and Low Temperature Test Chamber

Temperature and humidity is the percentage of the amount of water vapor (vapor pressure) contained in a gas (usually air) and the amount of saturated water vapor (saturated vapor pressure) in the same case as the air, expressed in RH%. Humidity long ago had a close relationship with life, but it was difficult to quantify it. The expression of humidity is humidity, relative humidity, dew point, ratio of moisture to dry gas (weight or volume), and so on.

Humidity measurement method hygrograph humidity measurement from the principle of the division of twenty or thirty. But humidity measurement is always one of the difficult problems in the world measurement field. A seemingly simple quantity value, in depth, involves quite complex physico-chemical theoretical analysis and calculation, beginners may ignore many factors that must be paid attention to in humidity measurement, thus affecting the reasonable use of sensors.

Common humidity measurement methods are: dew point method, wet and dry bulb method and electronic sensor method, dynamic method (double pressure method, double temperature method, shunt method), static method (saturated salt method, sulfuric acid method)

1, Dew point method hygrograph: is to measure the temperature when the wet air reaches saturation, is a direct result of thermodynamics, high accuracy, wide measurement range. Precision dew point instrument for measurement can reach ±0.2°C or even higher accuracy. However, the cold mirror dew-point meter with modern optoelectric principle is expensive and often used with standard humidity generators.

2, Wet and dry bulb hygrometer: this is a wet measurement method invented in the 18th century. It has a long history and is widely used. Wet and dry bulb method is an indirect method, which converts the humidity value from the wet and dry bulb equation, and this equation is conditional: that is, the wind speed near the wet bulb must reach more than 2.5m/s. The common wet and dry bulb thermometer simplifies this condition, so its accuracy is only 5~7%RH, and the wet and dry bulb does not belong to the static method, do not simply think that improving the measurement accuracy of the two thermometers is equal to improving the measurement accuracy of the hygrometer.

3, Electronic humidity sensor method hygrometer: electronic humidity sensor products and humidity measurement belong to the industry that rose in the 1990s in recent years, at home and abroad in the field of humidity sensor research and development has made great progress. Humidity sensors are developing rapidly from simple humidity sensors to integrated, intelligent, multi-parameter detection, creating favorable conditions for the development of a new generation of humidity measurement and control systems, and also raising humidity measurement technology to a new level.

4, Double pressure method, double temperature hygrometer: is based on the thermodynamic P, V, T balance principle, the balance time is longer, shunt method is based on the precise mixing of moisture and dry air. Due to the use of modern measurement and control means, these devices can be quite precise, but because of the complex equipment, expensive, time-consuming operation, mainly used as standard measurement, its measurement accuracy can reach ±2%RH or more.

5, Static method of saturated salt hygrometer: is a common method in humidity measurement, simple and easy. However, the saturated salt method has strict requirements for the balance of liquid and gas two phases, and high requirements for the stability of ambient temperature. It requires a long time to balance, and low humidity points require even longer. Especially when the humidity difference between the indoor and the bottle is large, it needs to be balanced for 6 to 8 hours each time it is opened.

The Role of High and Low Temperature Test Chamber for Electronic Component Testing

High and low temperature test chamber is used for electronic and electrical components, automation parts, communication components, automotive parts, metal, chemical materials, plastics and other industries, national defense industry, aerospace, military, BGA, PCB substrate wrench, electronic chip IC, semiconductor ceramic magnetic and polymer material physical changes. Testing the performance of its material to withstand high and low temperatures and the chemical changes or physical damage of the product in thermal expansion and contraction can confirm the quality of the product, from precision ics to heavy machinery components, will be an essential test chamber for product testing in various fields.

What can the high and low temperature test chamber do for electronic components? Electronic components are the foundation of the whole machine and may cause time - or stress-related failures during use due to their inherent defects or improper control of the manufacturing process. To ensure the reliability of the entire batch of components and meet the requirements of the entire system, you need to exclude the components that may have initial faults under operating conditions.

1. High temperature storage

The failure of electronic components is mostly caused by various physical and chemical changes in the body and surface, which are closely related to temperature. After the temperature rises, the chemical reaction speed is greatly accelerated, accelerating the failure process. The defective components can be exposed in time and eliminated.

High temperature screening is widely used in semiconductor devices, which can effectively eliminate failure mechanisms such as surface contamination, poor bonding and oxide layer defects. Generally stored at the highest junction temperature for 24 to 168 hours. High temperature screening is simple, inexpensive and can be carried out on many parts. After high temperature storage, the parameter performance of components can be stabilized and the parameter drift in use can be reduced.

2. Power test

In the screening, under the combined action of thermoelectric stress, many potential defects of the body and surface of the component can be well exposed, which is an important project of reliability screening. Various electronic components are usually refined for a few hours to 168 hours under rated power conditions. Some products, such as integrated circuits, can not arbitrarily change the conditions, but can use high temperature working mode to increase the working junction temperature to achieve a high stress state. Power refining requires special test equipment, high and low temperature test chamber, high cost, screening time should not be too long. Civilian products are usually a few hours, military high-reliability products can choose 100,168 hours, and aviation-grade components can choose 240 hours or longer.

3. Temperature cycle

Electronic products will encounter different ambient temperature conditions during use. Under the stress of thermal expansion and contraction, components with poor thermal matching performance are easy to fail. Temperature cycle screening utilizes the thermal expansion and contraction stress between extreme high temperature and extreme low temperature to effectively eliminate products with thermal performance defects. The commonly used component screening conditions are -55~125℃, 5~10 cycles.

Power refining requires special test equipment, high cost, screening time should not be too long. Civilian products are usually a few hours, military high-reliability products can choose 100,168 hours, and aviation-grade components can choose 240 hours or longer.

4. The necessity of screening components

The inherent reliability of electronic components depends on the reliability design of the product. In the manufacturing process of the product, due to human factors or fluctuations in raw materials, process conditions, and equipment conditions, the final product can not all achieve the expected inherent reliability. In every batch of finished products, there are always some products with some potential defects and weaknesses, which are characterized by early failure under certain stress conditions. The average life of early failed parts is much shorter than normal products.

Whether electronic equipment can work reliably depends on whether electronic components can work reliably. If the early failure parts are installed together with the whole machine equipment, the failure rate of the early failure of the whole machine equipment will be greatly increased, and its reliability will not meet the requirements, and it will also pay a huge price to repair.

Therefore, whether it is a military product or a civilian product, screening is an important means to ensure reliability. High and low temperature test chamber is the best choice for the environmental reliability test of electronic components.

What are the Reliability Tests for Light Emitting Diodes for Communication?

Failure determination of light emitting two tubes for communication:

Provide a fixed current to compare the optical output power, if the error is greater than 10%, the failure is determined.

Mechanical stability test:

Shock test: 5tims/axis, 1500G, 0.5ms Vibration test: 20G, 20 ~ 2000Hz, 4min/cycle, 4cycle/axis Liquid thermal shock test: 100℃(15sec)←→0℃(5sec)/5cycle

Durability test:

Accelerated aging test: 85℃/ power (maximum rated power)/5000 hours, 10000 hours

High temperature storage test: maximum rated storage temperature /2000 hours

Low temperature storage test: maximum rated storage temperature /2000 hours

Temperature cycle test: -40℃(30min)←85℃(30min), RAMP: 10/min, 500cycle

Moisture resistance test: 40℃/95%/56 days, 85℃/85%/2000 hours, sealing time

Communication diode element screening test:

Temperature screening test: 85℃/ power (maximum rated power)/96 hours screening failure determination: Compare the optical output power with the fixed current, and determine failure if the error is larger than 10%

Communication diode module screening test:

Step 1: Temperature cycle screening: -40℃(30min)←→85℃(30min), RAMP: 10/min, 20cycle, no power supply

Second: Temperature screening test: 85℃/ power (maximum rated power)/96 hours

Working Principle and Classification of Vacuum Pump in Vacuum Drying Oven

1, The working pressure of the vacuum pump should meet the limit vacuum and working pressure requirements of the vacuum equipment, and the best value of the vacuum degree of the selected vacuum pump is 133pa=-0.1 mpa. Usually, the vacuum degree of the selected pump is half to an order of magnitude higher than the vacuum degree of the vacuum equipment.

2, Correctly select the working point of the vacuum pump. Each pump has a certain operating pressure range.

3, The vacuum pump under its working pressure, should be able to discharge all the gas generated in the process of vacuum equipment.

4, Correctly combine the vacuum pump. Because the vacuum pump has selective pumping, sometimes a pump can not meet the pumping requirements, and several pumps need to be combined to complement each other to meet the pumping requirements, such as titanium sublimation pump has a high pumping speed for hydrogen, but can not pump helium, and the three-pole sputtering ion pump, (or bipolar asymmetric cathode sputtering ion pump) has a certain pumping speed for argon, the combination of the two, It will make the vacuum device get a better vacuum degree. In addition, some vacuum pumps can not work at atmospheric pressure, need pre-vacuum; Some vacuum pump outlet pressure is lower than atmospheric pressure, the need for the front pump, so it is necessary to combine the pump to use.

5, Vacuum equipment for oil pollution requirements. If the equipment is strictly required to be oil-free, a variety of non-oil pumps should be selected, such as: water ring pumps, molecular sieve adsorption pumps, sputtering ion pumps, cryogenic pumps, etc. If the requirements are not strict, you can choose to have a oil pump, plus some anti-oil pollution measures, such as cooling trap, baffle, oil trap, etc., can also meet the clean vacuum requirements, our company's vacuum drying oven selection is rotary vane oil pump, its main characteristics: large force, fast speed, high efficiency.

6, Understand the composition of the gas being pumped, whether the gas contains condensable steam, whether there is particulate dust, whether there is corrosion, etc. When selecting a vacuum pump, you need to know the gas composition, select the appropriate pump for the gas being pumped. If the gas contains steam, particles, and corrosive gases, it should be considered to install auxiliary equipment on the pump inlet line, such as condenser, dust collector, or liquid water filter.

7, What is the impact of the oil steam discharged from the vacuum pump on the environment? If the environment is not allowed to have pollution, you can choose an oil-free vacuum pump, or exhaust the oil steam to the outside.

8, Whether the vibration generated by the vacuum pump during operation has an impact on the process and the environment. If the process does not allow, should choose non-vibration pump or take anti-vibration measures.

9, The price of vacuum pump, operation and maintenance costs.

  On November 30th, 2024, the Academic Committee of Building Electrical and Intelligent Building of Wuxi Civil Engineering Society was held in Wuxi Picturesque Hotel, representatives from more than 20 electrical equipment manufacturers attended the annual meeting.

  Anhui Jinli Electric is a technical service company specializing in the research and development, manufacturing, sales and overall lightning protection solutions of lightning protection products, and had a good interaction with the visiting representatives at the venue. The exhibits included sugre protection devices,  SPD backup protectors, backup integrated SPDs, signal surge protectors and intelligent lightning protection system, which attracted the attention and consultation of many representatives. As a professional lightning protection manufacturer, our company was also invited to make a company introduction at the conference.

  With the approval of the Wuxi Civil Engineering Society and the Building Electrical and Intelligent Building Professional Academic Committee, Anhui Jinli officially became a member unit of the Wuxi Civil Engineering Society and the Building Electrical and Intelligent Building Professional Academic Committee.

  Based on the corporate development philosophy of "protecting users from lightning", we are committed to the safety of electricity use in electrical systems, focusing on lightning protection technology for electrical systems, and independently developing lightning warning systems and intelligent lightning protection systems. We transform passive lightning protection into active protection, and decentralized protection into full-system intelligent protection, and establish a three-dimensional lightning protection and operation and maintenance management system. Creating the world's best lightning protection brand is our driving force for continuous progress, and we provide global customers with safer and more efficient lightning protection solutions.

As photovoltaic (PV) systems become more widespread, ensuring their safety and reliability is essential, especially in preventing lightning and surge interference. Low Voltage Surge Protection Device (SPD) play a critical role in PV systems by reducing the risk of equipment damage. Here are some important considerations for applying SPD in PV systems.

Ⅰ. Selection of SPD

PV systems have relatively high DC voltages, so it’s essential to choose SPD  that match the system’s voltage level. Ensure that the Voltage Protection Rating (VPR) of the SPD meets the safety requirements of the equipment. Pay special attention to the differences between DC and AC SPD.

Ⅱ. Installation Location of SPD

The installation location of the SPD is crucial; it should be as close as possible to key equipment like inverters and controllers. Additionally, SPD need to be installed at the equipment input to ensure that surges are suppressed before reaching the devices.

The proper design and installation of the grounding system in a PV system contribute to the effective performance of the SPD. It’s recommended to use a low-impedance grounding system to ensure that surge currents can be quickly dissipated, reducing the impact on the system.

Ⅳ. Regular Maintenance and Inspection

To maintain the effectiveness of SPD, regular inspections and maintenance are necessary. After stormy seasons, promptly replace any aged or failed SPDs to ensure the safe operation of the PV system.

With proper surge protector selection, installation, and maintenance, the surge resistance of PV systems can be significantly enhanced, extending their lifespan and ensuring stable operation.

  In this season full of vitality and innovation, we welcome the first Jinli Lightning Protection Production Skills Competition whichaims to stimulate employees' enthusiasm for learning professional skills through a series of carefully designed competition projects, promote the collaboration ability and technical level among teams, and also build a good platform for knowledge exchange and technology sharing within the company.

  This competition has five projects, covering multiple key links from varistor assembly to manual circuit board insertion, the process for producing surge protection device, including https://www.jinlispd.com/ac spd, dc spd, pcb spd etc.  

  The competition attracted 145 participants from different departments. They not only demonstrated their own methods and skills, but also promoted knowledge exchange and technology sharing within the company through cross-departmental communication and collaboration. In the intense and orderly competition, the contestants showed a strong sense of responsibility and high technical level, which fully demonstrated Jinli Lightning Protection's pursuit of excellence and strong corporate culture to ensure quality.

  Through this skills competition, we have seen the efforts and dedication of each participant, and also witnessed their breakthroughs in skills and efficiency. This is not only a display of personal ability, but also a reflection of teamwork spirit.

Choosing the best casters for outdoor use involves considering durability, load capacity, maneuverability, and resistance to outdoor elements. Outdoor casters are essential for applications like moving furniture, equipment, or garden structures, where they need to withstand uneven surfaces, moisture, and temperature changes. Here’s a quick guide to choosing the right caster for outdoor use.

Material

Outdoor casters are typically made from durable materials that can endure harsh environments. Swivel stainless steel casters, for example, are corrosion-resistant and can withstand moisture, while polyurethane casters provide a smooth roll over rough surfaces and resist damage from chemicals, oils, and abrasions.

Industrial rubber casters are also popular for outdoor use due to their flexibility and ability to handle rough and uneven ground. Hence, cast iron casters are not suitable for outdoor use.

Tread Type

A soft-tread one, such as rubber or polyurethane, shock absorbing casters from uneven surfaces, making it suitable for outdoor use. Soft-tread casters also provide good traction on wet surfaces, reducing the risk of slipping. For heavy-duty tasks, consider casters with pneumatic (air-filled) tires, which offer excellent cushioning and grip on varied terrains.

Top Recommendations

Polyurethane Casters: Known for durability and smooth operation, polyurethane casters handle rough outdoor surfaces well and are resistant to various chemicals, making them ideal for gardens and outdoor warehouses.

Stainless Steel Casters: Perfect for environments where moisture is a concern, these casters resist rust and are suited for outdoor furniture and equipment that might be exposed to rain or snow.

Pneumatic Casters Wheels: Equipped with air-filled tires, these are ideal for heavy-duty applications on rough or uneven ground. They offer great shock absorption, making them suitable for outdoor activities and construction sites.

When selecting casters for outdoor use, consider the specific environment and load requirements to ensure safety and longevity.

When choosing a Heavy Duty Outdoor Caster Wheels, there are several important factors to consider:

Wheel Grip

Excellent grip is essential when choosing wheels that can carry heavy loads outdoors,such as Heavy Duty Industrial Trolley Wheels. These wheels are usually designed for high performance, have excellent shock absorption, and can easily navigate rough or uneven surfaces.

Turning Radius

The turning radius refers to the amount of space required for the reel to swing or turn. For Outdoor Industrial Metal Casters, choosing a larger turning radius reduces the force required to change direction, providing smoother, more efficient movement.

Maneuverability

Efficient maneuverability is especially important for outdoor spaces. Heavy-duty swivel wheels allow for greater flexibility and smoother movement than fixed casters. For precise control, consider a swivel lock or heavy duty kingpinless casters design that eliminates pan head errors and provides greater steering accuracy.

Load Capacity

Before choosing a heavy duty caster, it is important to understand the total load capacity of the caster set. This includes not only the weight of the object, but also the weight of the cart or equipment the pulley is attached to.

Conclusion

These are the most important considerations when choosing a heavy-duty outdoor caster. YLcaster is one of the leading industrial casters and wheels manufacturers in China, offering a wide range of options to suit every need.

Visit our website to learn more about our quality casters and feel free to contact us for expert advice and recommendations on the solution that best suits your industrial needs.

The latest trends in furniture caster wheels revolve around smart features, sustainability, customization, and functionality. Smart casters integrate sensors for motion detection and automatic locking, while eco-friendly materials like recycled plastics and bamboo are increasingly used to align with sustainability goals. Customization options such as varied colors and designs cater to individual tastes and interior decor styles.

Furniture casters for hardwood floors with noise reduction features like rubberized treads or specialized designs aim to minimize disturbances. Multi-functional casters enable furniture pieces to transform easily, optimizing space in smaller living environments. Minimalist designs with clean lines are favored, ensuring casters blend seamlessly with modern furniture aesthetics.

In industrial and commercial settings, heavy-duty casters made from advanced materials like high-strength steel alloys cater to transporting heavy loads, often incorporating swivel locks and brake systems for safety. Additionally, there's a growing demand for antimicrobial casters, particularly in healthcare and hospitality sectors, to enhance hygiene and reduce the spread of pathogens. These trends reflect a combination of consumer preferences, technological advancements, and a focus on sustainability and functionality in furniture design.