The rotary drum vacuum filter invented in the early 20th century has realized the continuous operation of filtration. The real large-scale use of filters in electroplating enterprises should begin in the 1970s when bicycles entered ordinary families. Motorcycles and household appliances gradually became popular in the 1980s, and private cars in the 1990s promoted the popularization of filters. Under the action of vacuum negative pressure (0.04-0.07 MPa), the liquid in the suspension is removed through the filter medium (filter cloth), while the solid particles are intercepted by the medium, thus realizing the separation of liquid and solid. The same welding operation is then started on the other side of the sandwich plate. In order to avoid welding cracks, pulse mode is used in spot welding, and power slope is used at the end of the pulse to reduce cooling rate. Therefore, in the long run, the functions, forms and models of filters can meet the needs of domestic electroplating enterprises. The key point is to further improve the quality of the filters. With the improvement of electroplating technology, the filters'materials, processing technology and filter media are developed accordingly.
At present, the plating solution filters manufactured in China are mainly equipped with low-lift centrifugal pumps. The filter media used are filter paper, filter membrane, activated carbon, ceramics, etc. In the form of winding, stacking, carambola, bag and so on. The filtering accuracy can also be chosen according to the requirements of plating process. The amateur watches the busy and professional doorway. What arouses the experts'interest is how to deal with the shiny decorative parts of the car. So he visits the FAW car production line and finds that there are recycling filters imported from abroad on the plating production line.
Laser spot welding is carried out one by one from one side of sandwich plate in horizontal direction, and continuous welding operation is carried out by controlling the opening/closing time of grating at each line of spot welding. This operation is repeated until the welding of the other edge is completed, and then the other side of the sandwich plate is welded with the same operation as above. The weld seam is relatively smooth bead-like without surface defects. The welding speed can reach 2.6 mm/min, the laser power is 3 kW, and the wire feeding speed is 3 mm/min. At the same time, with the improvement of automation level of electroplating production line, the demand for filters has also increased and improved. Domestic filters have been developing domestically on the basis of importing and absorbing foreign products. This structure seems problematic to many engineers, especially when exposed to flame or immersed in water.
In ancient China, filter technology was used in production. Rubber belt vacuum filter was sold. Paper made of plant fibers was available in 200 B.C.
Most of the earliest filters were gravity filters. Later, pressure filters were used to improve the filtration speed, and then vacuum filters came into being.
Another demonstration plate for Ex-StructTM sandwich panels was fabricated by Nd:NAG laser buttress welding. The structure of the filter section is arranged along the horizontal length direction. The rubber belt vacuum filter can continuously complete the filtering, washing, drying and regeneration of the filter cloth.
According to the Welding Research Institute, they used laser spot welding and laser strut welding to demonstrate the feasibility of sandwich plate manufacturing and determine the key factors affecting welding quality and deformation. It is said that the use of 4047 alloy (Al-13%Si) filler wire with a diameter of 1.2 mm can reduce solidification cracks and obtain smooth Beaded surface. Functionally, there are ordinary electroplating solution filtration, pre-plating solution degreasing filtration, activated carbon filtration, as well as specific electroless plating, chromium plating filter.
The filter is a kind of equipment which uses porous filter medium to intercept solid particles in the mixture of liquid and solid particles and realize solid-liquid separation.
Rubber belt vacuum filter is a kind of equipment which uses vacuum negative pressure as driving force to realize solid-liquid separation. During this period, the demand for a large number of civilian products such as lamps, plumbing, decorative hardware and so on increased, which led to the rapid development of electroplating industry. At that time, there was a saying that "if we want to be rich in electroplating", we can see that. In terms of form and function, domestic filters are rich in varieties, but because of the weakness of basic industries, there is still a certain gap between quality and import filters. Therefore, the Ministry of Machinery and the Institute of Material Protection took the lead in organizing and tackling key problems. The crack sensitivity of weld can be reduced by controlling the slope of laser power. The hardness and strength of these materials are very important functions. At that time, the processing of parts and components in China's machinery manufacturing industry was still in the process of applying butter as rust prevention. Decorative electroplating parts were rarely used. There were only a few professional electroplating enterprises in the country, and a few electroplating parts were attributed to heat treatment workshop. It can be widely used in solid-liquid separation in metallurgy, mining, chemical industry, paper-making, food, pharmaceutical, environmental protection and other fields, especially in gypsum dehydration in flue gas desulfurization (FGD) has good application. At the beginning of this century, a large number of filters in Taiwan and other regions began to enter the mainland market. The Self-priming pumps mainly equipped with them have brought new impetus to the domestic filter manufacturers, and promoted the development and application of self-priming pumps in China.
Filters are widely used in chemical, petroleum, pharmaceutical, light industry, food, mineral processing, coal and water treatment and other parts.
The introduction and localization of filters have also undergone a long process. In 105 AD, the rubber belt vacuum filter joined Shan. Cai Lun improved the paper-making method. In the paper-making process, he poured the plant fiber pulp on the dense fine bamboo curtain. The water was filtered through the cracks in the bamboo curtain. A thin layer of wet pulp was left on the bamboo curtain surface and dried into paper.
Light aluminium sandwich panels have been widely used in a variety of transport vehicles with different speeds: Conggong