When more and more SHOPPINGMALL exceeds 100,000 square meters, when more and more large indoor spaces are faced with large space and insufficient monitoring, when we have been supplemented by the heavy-duty indoor positioning system of WIFI, Bluetooth, etc. When there are frequent large errors, people are looking for indoor positioning technology that is more reasonable and more responsive to future developments. The rapid popularization of LED lights has made visible light communication technology (LED white light communication technology) the latest and most anticipated indoor positioning technology, solving the problem that has once plagued all indoor positioning technologies with a positioning accuracy of more than 5 meters. For the first time, the positioning accuracy is limited to 1 meter. ! Both foreign and domestic technology pioneers focus on LED white indoor positioning technology, but only China has taken the lead in completing the process from technology to commercialization. The accuracy of indoor positioning technology was as early as 2011. When Google [microblogging] mobile phone map version 6.0 was released, it has already added indoor navigation functions in some areas. This solution mainly relies on GPS (indoors, it can also search 2 to 3 satellites). ), wifi signal, mobile phone base station and local positioning according to the specific location of some blind spots (where there is no GPS, wifi or base station signal). Although this solution was not perfect at the time, there were obvious defects in both positioning accuracy and signal stability. Therefore, Google’s mobile phone map is more conceptual innovation, and it does not have technical operability. universality. However, it still caused a sensation at that time, and people felt the breakthrough progress of indoor positioning technology. In September 2013, Apple added a technology feature called iBeacon on the newly released mobile device, which caused the crazy pursuit of fruit powder. Although fruit powders are bought, the technology mainly uses Bluetooth technology to achieve indoor positioning. In the eyes of researchers, this is not the most accurate, nor is it the most stable indoor positioning technology. Because whether it is GPS or WIFI, or Bluetooth, the technical flaws are especially obvious in terms of accuracy. The positioning accuracy of GPS is 10 to 100 meters, and it has to be affected by the environment. It needs multi-point positioning and data matching to complete, and the reaction speed is relatively slow. Although the technology of WIFI and Bluetooth is relatively mature at present, by relying on the principle that the wireless signal of the mobile phone and the WiFi wireless network is attenuated in the air, the indoor position is determined by measuring the intensity of the wireless signal and calculating the attenuation distance. However, since the attenuation of wireless signals in the air is greatly affected by the environment inside the building, the positioning is very inaccurate. However, there is still no way to locate the accuracy less than 5 meters, and the floor recognition of the indoor space is not high, and the signal stability and confidentiality of information transmission are difficult to guarantee. Although many international universities, research institutes, and business circles such as Google, Nokia [microblogging], Motorola [microblogging], and Microsoft [microblogging] have conducted a lot of research, they have been unable to surpass theoretical obstacles. In the outdoor omnipotent traditional navigation, the indoor positioning of the last mile navigation has an insurmountable scale and precision. LED indoor positioning technology, however, as early as the early 21st century, technical experts in many countries saw another possibility, an environmentally friendly, energy-saving lighting new material LED, technical experts in fluorescent lights or LEDs The high-speed light and dark flickering signals that are invisible to the naked eye can not only be used to transmit information, but if positioned, the positioning accuracy can reach 1 meter! This completely overturns people's understanding of general lighting, so experts around the world are studying how to use the white light in the LED to transfer from information to information reception. In the end, people discovered the mystery from the smartphone. The camera of the smartphone can be used as a terminal to receive information. Tang Haijun, the deputy director of the operation of Huashiguang Communication Technology Co., Ltd., the first company in China that owns the independent property rights of LED white light indoor positioning technology and realizes commercial operation, said that this technology is not only a revolution of intelligent lighting, but also solved indoors. Positioning the precise problems in history. The principle of the technology is to compile the information to be transmitted into a modulated signal, and attach it to the driving current of the LED lamp by pulse width modulation, so that the ubiquitous light source in the user acts as a launching carrier, and when the user enters the lighting area of ​​the lamp, The smart signal received without any hardware receives and recognizes the optical signal, and resolves the unique identification information sent by the luminaire. The corresponding location information is determined in the map database by using the acquired identification information, and the positioning is completed. In the opinion of technical experts, this technology almost solves the shortcomings of all previous indoor positioning technologies: positioning accuracy reaches 1 meter, signal stability, high information confidentiality, and no environmental impact. Global technology research and development experts are looking at it. Aiming at visible light communication technology. Whether it is Japan, South Korea, the United States or China, it is committed to the practical use of the technology. Bytelight, a company established in the United States in 2011, is the most concerned company in the field. From the initial development stage to the completion of financing, the company will soon cooperate with lighting manufacturers to enter the actual production stage. In contrast, China's pace is moving faster. Huace Optical Communication Technology Co., Ltd., as a project in cooperation with the National Semiconductor Lighting Innovation Lab, independently developed a U-beacon indoor positioning system based on LED white light positioning technology, using a CMOS camera for visible light signal reception, unlike using a photodiode to receive Visible light compensates for the lack of interference from other surrounding light sources in other countries in terms of visible light signal reception. In the middle of this year, it realized commercial operation and launched the world's first application APP with 3D360 real-life maps. It has already started trial operation in Changzhou, Jiangsu. Of course, there are other possibilities for technicians to see from the Internet. Fudan University developed the Internet access technology under the optical positioning system based on this technology, but this is only a conceptual technology. Due to the influence of hardware and environment, it can only be realized in a small scope. The multi-dimensional application prospect of visible light communication is only the initial stage. For WIFI and Bluetooth positioning, using visible light for positioning, not only the initial installation cost is low, but also does not need to re-scan signal strength like WIFI and Bluetooth, and the maintenance cost is low, plus the advantage of positioning accuracy, people's future for visible light communication More optimistic. Not only technical improvement, but more multi-dimensional presentation at the application level. According to the report, as of January 2014, the total number of mobile Internet users in China reached 838 million, and the penetration rate among mobile phone users reached 67.8; the number of mobile Internet users reached 500 million, accounting for more than 80% of the total number of Internet users. Internet terminal status. The development of China's mobile Internet has entered the era of the whole people. At the same time, in China, LED has become the development trend of future lighting. According to research statistics, many company executives and industry experts believe that 2013-2015 will be a period of rapid growth in LED lighting penetration. In 2015, domestic LED penetration rate will be Up to 50. At present, the majority of commercial sites are replacing LED light sources. Ubeacon technology aims to add a low-cost original to the existing light source, which can be promoted along with the LED replacement wave. Tang Haijun, deputy general manager of Huace Optical Communication Technology Co., Ltd., believes that in the commercial operation, the role of visible light communication technology is more obvious, and the technology is combined with smart phones and networks, and through the panoramic display of indoor 3D360 real-life maps, It will provide significant support for the construction of the O2O platform for future physical businesses. Therefore, they are seeking cooperation in commercial projects in first- and second-tier cities across the country. LED lamps and smart phones, which are the two major hardware for realizing visible light communication, the large-scale popularization of hardware has given more possibilities to the intelligent development of LED indoor positioning technology to a certain extent. In the eyes of professional technicians and operational experts, the application of this technology is not only in the commercial field, but also in many industries, and its future development has a prospect that cannot be ignored. At present, the prototypes have been found in the underground positioning system and in the special industry. Both systems can confirm the relevant position information in real time through the accuracy, stability and convenience of optical positioning, and perform safety control and disaster warning. At the same time, one-to-one confidentiality of optical positioning transmission can be used. Information transmission in special industries. Of course, the bolder imagination is that, perhaps one day, the use of this optical positioning technology is not limited to indoor space, but it can even be used in certain outdoor environments in the case of extremely high LED penetration. Perhaps, not only the WIFI that is deeply dependent on today, but even the various outdoor LED displays can realize its intelligent application.

ALFA LAVAL Plate Heat Exchanger

Alfa Laval Heat Exchanger

Double-Wall Plate Heat ExchangerGasketed plate heat exchangers (PHE) meets almost all of heat transfer requirements. They are highly flexible with a wide range of models. Connection sizes range from 1″ to 16″. Plate materials are available in a wide variety such as stainless steel 316, 304 and titanium. Other alloys for corrosive applications such as Hastelloy, Nickel and monel are also available.

A flat Plate Heat Exchanger transfers heat between two different fluids using metal plates to separate the fluids. The fluids move between the gaps in the plates. The plates are corrugated in a chevron pattern causing high turbulence in the fluids. The high turbulence and high surface area of the plates results in a higher efficiency of heat transfer than conventional shell and tube heat exchangers.

Advantages of Plate Heat Exchangers:

Because the flow pattern causes high turbulence of the fluids through alternate channels – this results in a higher heat transfer rate allowing for a more compact design reducing material cost since the heat transfer surface requirement is much lower than a conventional heat exchanger.
High turbulence results in less fouling – therefore less down time for maintenance.
Easily add capacity as expansion is required by adding plates to the heat exchanger.
Can be opened without disturbing the piping.
Closer temperature approaches of up to 2°F maximizes heat recovery for a wide variety of applications.
Minimal space required for opening or closing the heat exchanger allows for easy maintenance.
Ideal for mounting on a skid.
Flow principle of Plate And Frame Heat Exchangers:

Plate and frame heat exchangers consists of a pack of thin metal plates with openings for the passage of the fluids. The plates are corrugated which means that each pair of adjacent plates in the heat exchanger forms a channel. Every second channel is open to the same fluid. Between each pair of plates there is a rubber gasket, which prevents the fluids from mixing and from leaking to the surroundings.

When the media enters the plate and frame heat exchanger via the connections in the frame, it`s directed through alternate channels by the gasket arrangement. The warm fluid flows through every other channel and the cold fluid through the channels in between. Heat is thus transferred from the warm fluid to the colder fluid via the dividing wall, i.e. the plate material. The corrugations support the plates against differential pressure and create a turbulent flow in the channels. In turn, the turbulent flow provides high heat transfer efficiency, making the plate heat exchanger very compact compared with the traditional shell-and-tube heat exchanger.

The Double-Wall Plate Heat Exchanger:

For fluids that must be kept separate

The Double-Wall Plate Heat Exchanger is a technical breakthrough for heat exchange for media between which a hostile or undesirable reaction can occur, if the two fluids should mix. The Double-Wall Plate Heat Exchanger is therefore a new alternative to traditional heat transfer equipment such as the double-wall shell-and-tube heat exchanger, the triple-tube shell-and-tube heat exchanger, the double-circuit intercooler, and coils for indirect heating.



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