Refrigeration Equipment Type Introduction(1)

Refrigeration equipment

Refrigeration equipment is a combination of a chiller and a facility that uses cold capacity. Refrigeration units are designed and constructed to efficiently use cold quantities to refrigerate food or other items; to perform product performance tests and scientific research tests at low temperatures; to achieve certain cooling processes in industrial production, or to perform air conditioning. When the item is cooled or frozen, a certain amount of heat is released, and the enclosure of the refrigeration unit also introduces a certain amount of heat when it is used. Therefore, in order to maintain the low temperature conditions in the refrigeration unit, it is necessary to install a refrigerator to continuously remove the heat, or to absorb the heat by melting the ice or sublimation of the dry ice.



Condenser

The high-pressure high-temperature refrigerant vapor sent from the compressor is condensed into a liquid. There are three types of commonly used condensers: 1 water-cooled. With water as the coolant, there are tube condensers, sleeve condensers and spiral plate condensers. 2 spray type. At the same time, water and air are used as coolants, there are spray condensers (air is natural convection) and evaporative condensers (air is forced convection). 3 air-cooled. Air is used as a coolant, ie an air condenser.







Tag: Refrigeration Equipment

The Necessity And Inspection Method Of PCBA Detection

As a platform for the transmission of many components and circuit signals, the printed circuit board (PCB) has always been regarded as a key part of electronic information products, and its quality determines the quality and reliability of the final product. Due to the development trend of high density, lead-free and halogen-free environmental requirements, if professional and timely inspections are not completed, various failure problems may occur, such as poor wettability, cracks, delamination, etc.
Detection Technology
Generally, PCBA assembly inspection technology is divided into two types: visual inspection and automatic process inspection.
A. Visual inspection
After a large number of steps in the PCB assembly process, visual inspection can be used, and the visual inspection equipment is selected according to the position of the inspection target. The effectiveness of the visual inspection depends on the competence of the inspectors, the consistency and applicability of the inspection standards.
Inspectors must be fully aware of the technical requirements for each type of solder joint, as each type of solder joint may contain up to 8 defect criteria, and there may be more than 6 solder joints on different assembly equipment. Therefore, visual inspection is not suitable for quantitative measurement of effective structural process control.
B. Structural Process Test System (SPTS)
Digitization and analysis systems for real-time and automatic video capture can significantly improve the tolerance and repeatability of visual inspection. Therefore, structural process test systems rely on certain forms of emitted light, such as visible light, laser beams, and X-rays. All of these systems process images to obtain information to identify and measure defects related to solder joint quality.
C. Automatic / Automatic Optical Inspection (AOI)
The AOI system relies on multiple light sources, a programmable LED library, and some cameras to illuminate the solder joints and shoot. Under reflected light, the leads and solder joints reflect, reflecting most of the light, while PCB and SMD reflect very little light. The light reflected from the solder joint does not provide actual height data, while the pattern and intensity of the reflected light provides information about the curvature of the solder joint. A professional analysis is then performed to determine if the solder joints are complete, whether the solder is sufficient, and if wetting has not occurred.
D. Automatic laser test (ALT) measurement
ALT is a more direct technique for testing height and shape solder joints or paste deposits. When the image of the laser beam is focused on one or more position-sensitive detectors at an angle to the laser beam, the system is used to measure the height and reflectance of some surface parts.
During the ALT measurement, the surface height is determined by the position of the light reflected by the position-sensitive detector, and the surface reflectance is calculated from the power of the reflected beam. Due to the secondary reflection, the beam may illuminate a position-sensitive detector at multiple locations, which requires a solution to distinguish the correct measurement.
In addition, when traveling along the light of the position sensitive detector, the reflected light beam may be shielded or interfered by interfering materials. To eliminate multiple reflections and prevent shielding, the system should test the reflected laser beam along an adjusted independent optical path.
How to determine the PCB assembly inspection method?
Despite the variety of detection methods, there is a big difference between AOI inspection and X-ray inspection. The three factors to consider when determining the inspection method are defect type, cost, and inspection speed. When it comes to defect types AOI and X-ray coverage, AOI is usually used for inner layer testing before lamination. Defect items include solder paste amount, component location, missing and polarity, and solder joint defects.
The above is a detailed introduction to the common methods of testing printed circuit boards. If you have any questions about our answer, you can contact us.

The Necessity And Inspection Method Of PCBA Detection

As a platform for the transmission of many components and circuit signals, the printed circuit board (PCB) has always been regarded as a key part of electronic information products, and its quality determines the quality and reliability of the final product. Due to the development trend of high density, lead-free and halogen-free environmental requirements, if professional and timely inspections are not completed, various failure problems may occur, such as poor wettability, cracks, delamination, etc.
Detection Technology
Generally, PCBA assembly inspection technology is divided into two types: visual inspection and automatic process inspection.
A. Visual inspection
After a large number of steps in the PCB assembly process, visual inspection can be used, and the visual inspection equipment is selected according to the position of the inspection target. The effectiveness of the visual inspection depends on the competence of the inspectors, the consistency and applicability of the inspection standards.
Inspectors must be fully aware of the technical requirements for each type of solder joint, as each type of solder joint may contain up to 8 defect criteria, and there may be more than 6 solder joints on different assembly equipment. Therefore, visual inspection is not suitable for quantitative measurement of effective structural process control.
B. Structural Process Test System (SPTS)
Digitization and analysis systems for real-time and automatic video capture can significantly improve the tolerance and repeatability of visual inspection. Therefore, structural process test systems rely on certain forms of emitted light, such as visible light, laser beams, and X-rays. All of these systems process images to obtain information to identify and measure defects related to solder joint quality.
C. Automatic / Automatic Optical Inspection (AOI)
The AOI system relies on multiple light sources, a programmable LED library, and some cameras to illuminate the solder joints and shoot. Under reflected light, the leads and solder joints reflect, reflecting most of the light, while PCB and SMD reflect very little light. The light reflected from the solder joint does not provide actual height data, while the pattern and intensity of the reflected light provides information about the curvature of the solder joint. A professional analysis is then performed to determine if the solder joints are complete, whether the solder is sufficient, and if wetting has not occurred.
D. Automatic laser test (ALT) measurement
ALT is a more direct technique for testing height and shape solder joints or paste deposits. When the image of the laser beam is focused on one or more position-sensitive detectors at an angle to the laser beam, the system is used to measure the height and reflectance of some surface parts.
During the ALT measurement, the surface height is determined by the position of the light reflected by the position-sensitive detector, and the surface reflectance is calculated from the power of the reflected beam. Due to the secondary reflection, the beam may illuminate a position-sensitive detector at multiple locations, which requires a solution to distinguish the correct measurement.
In addition, when traveling along the light of the position sensitive detector, the reflected light beam may be shielded or interfered by interfering materials. To eliminate multiple reflections and prevent shielding, the system should test the reflected laser beam along an adjusted independent optical path.
How to determine the PCB assembly inspection method?
Despite the variety of detection methods, there is a big difference between AOI inspection and X-ray inspection. The three factors to consider when determining the inspection method are defect type, cost, and inspection speed. When it comes to defect types AOI and X-ray coverage, AOI is usually used for inner layer testing before lamination. Defect items include solder paste amount, component location, missing and polarity, and solder joint defects.
The above is a detailed introduction to the common methods of testing printed circuit boards. If you have any questions about our answer, you can contact us.

How Thermoformed Waterproof Stone Paper Is Environmentally Friendly

Waterproof stone paper is particularly prominent in environmental protection. Compared with the traditional papermaking process, the production process does not produce waste water, waste gas, waste residue, and is a pollution-free green environmental protection project. In terms of water use, traditional papermaking consumes 100 tons of fresh water per ton of production, while the stone paper production process requires no water for the entire production.

In terms of raw materials, the main raw material of traditional papermaking is forest resources, while the main raw material of stone paper production process is coal gangue, slag and other stones, which do not consume forest resources. Traditional fiber paper can be recycled into recycled paper after use up to realize resource reuse. Thermoformed stone paper can also be recycled and reused. After recycling, it can produce dark-colored packaging paper, can also be made into various signs, flower pots, etc., and the used stone paper is recycled or treated as garbage.

When incinerated, only non-toxic resin can be burned. Stone powder can promote the contact between resin and air, accelerate the complete combustion, and avoid black smoke caused by suffocation due to lack of oxygen. There is no toxic exhaust gas after combustion. Helps mitigate and improve global warming caused by carbon dioxide.

Even if discarded outdoors, the stone paper will automatically embrittle into a broken eggshell shape after being exposed to sunlight for about 6 months, reducing the earth and returning to nature; it can be degraded into a powder (inorganic mineral powder) after being buried in the ground for 1 year. Will cause environmental pollution. It can replace a part of traditional wood papermaking.

In general paper, it may use a lot of water in the process of making it, but thermoforming stone paper hardly uses water, and the process does not bleach. So the biggest difference between us and ordinary paper is that the original color of stone powder will affect the color of paper. For example, coal gangue paper will be slightly black, depending on the purpose of the paper.

Functional Thermoformed Notebook Stone Paper

This project is dedicated to the development and research of functional thermoformed stone paper packaging materials. Applying the idea of ​​integrated innovation, using stone paper as the raw material, combining the excellent properties of stone paper with the mechanical properties of honeycomb paperboard and corrugated paperboard, the development of stone paper composite corrugated paperboard and stone paper honeycomb paperboard with various functions and its Related production processes, and creatively introducing foaming technology into the production of stone paper, reducing the proportion and cost of stone paper materials.

Through the research and development of stone paper production technology and the exploration of performance characteristics, the application of stone paper materials in the packaging field is promoted. The core layer of the stone paper honeycomb paperboard is formed by a chain compression molding process, that is, the core layer is pressed by the core paperboard through a chain molding device with a protruding honeycomb hexagonal prism structure, and then the prepared core layer and the stone paper are pressed. Tissue paper is melt-bonded at an instant high temperature.

Compared with the traditional corrugated cardboard of the same specification, the stone paper composite corrugated cardboard with a thickness of 4.50mm has a break resistance of at least 2.5 times and a puncture strength of 1.7 times. The core layer of the stone paper corrugated cardboard adopts the extrusion flow calendering molding process, that is, the stone paper is directly extruded and cooled in a molten state through a corrugated die to obtain a core layer. Each bonding surface is pre-heated and bonded by instantaneous high-temperature hot-melt bonding. Compared with the conventional honeycomb paperboard of the same specification, the prepared honeycomb paperboard with a basis weight of 202g / m2 has a flattening strength of 2.6 times that of the traditional honeycomb paperboard, and the burst resistance is at least 2.5 times that.

Lightweight stone paper, which is a light weight multi-layer stone paper composed of foamed stone paper and non-foamed stone paper. Foaming and hot-melt compounding are the key technologies. Multi-channel extrusion is used. Machine, followed by hot press foaming. During the production process of lightweight stone paper, AC foaming agent with a weight percentage of 0.1 ~ 0.7% is selected for the foaming process, and the temperature of the multi-layer runner of the extruder is 160 ~ 170 degrees Celsius, and the hot-pressing foaming temperature is 180- 200 degrees Celsius