1.
Industrial Salt, Sodium Chloride content ≥
94.5%, granular. White.2. English name:sodium chloride
3.
Molecular formula:NaCl
4.
Package: 25kg / bag or 1000kg/jumbo bag
5.
CAS:7647-14-5
6.
Delivery time:30 days
Use instructions:
Industrial
salt, also known as "sodium chloride", which more than 14,000 uses are found where you'd least expect
salt, these include:
·Treatment
·Freezing
Point depletion
·Skins
and Hides industry
·Fertilizer
applications
·Animal
health (animal feeds and supplements)
·Various
chemical and industrial applications
·Fishing
industry
·Food
ingredients
·De-icing
Abstract: Cable laying is a key construction project in electrical engineering, affecting the progress of the entire project. The laying of the entire cable is a system with numerous complicated procedures. It is easy to have some quality problems. Therefore, ensuring the quality of the cable laying process is the basis and key point for maintaining the operation of the power plant. This paper uses a power plant as a case study to discuss the cable laying process. Construction and quality control.
Foreword:
The entire cable laying project can be divided into three levels: (1) secondary design; (2) construction process control (3) finishing work. To do the above work, we must not only talk theoretically or make a hard copy. We must combine the reality of the project and proceed from the actual situation to make quality and quality projects.
1. Introduction to the basic situation of the case
The power plant laying range of the 2x200MW project of No.5 and No.6 units of a power plant includes: main plant, network control building and boosting station, auxiliary plant in the plant area, ash removal, electric dust removal, coal extraction system and so on. The whole plant cable auxiliary facilities include: installation and installation of cable tubes throughout the plant, installation and installation of cable brackets, installation of cable trays throughout the plant, and fireproof construction of cables.
2. Preparation before construction
Cable engineering is a systematic project. It is not possible to consider cable laying alone. The preparatory work in the early stage and the auxiliary facilities of the cable are also very important. After the construction drawings arrive at the site of the 2x200MW project of Units 5 and 6, immediately call the experienced technicians to carefully compare the cable laying diagram, cable inventory, and the secondary and secondary wiring diagrams and schematic diagrams, and reduce as much as possible. In the future, the design of the cable will be changed to prevent the overall layout from being damaged by a large number of cables. A small increase in cable is inevitable and will not affect the entire cable count process. Under the premise of ensuring that the design is basically correct, the secondary design is carried out. The auxiliary works of the cable mainly include cable casings, cable supports and cable trays. The installation of the cable casing is strictly in accordance with the specifications, and basically does not affect the process of cable laying. The cable branch and the bridge are the main passages of the cable. In order to lay the cable, the cable passage must be designed first.
3, cable laying steps and problems often encountered during construction
3.1 First find out the number of non-straight line segments with the largest number of cables, that is, intersections. This kind of place is the worst treatment in cable laying projects in the past. Accurately calculate the number of cables of various specifications in the lot, and calculate several cables on each shelf or bridge according to the cross-sectional area of ​​the cable of various specifications. This consideration must also strictly comply with the requirements of the specification. The cables are high-voltage power cables, low-voltage power cables, control cables, and signal cables from top to bottom , and the cable cross-sectional area on the same layer of brackets or bridges should be as close as possible or close to each other, so that it is more beautiful after laying. After the calculation, it can be seen whether the number and width of the original design of the bracket or the bridge layer meet the cable laying requirements, but in general, the theoretical calculation of the design is too small in the cable-intensive area, which cannot meet the requirements of on-site construction. In this case, it is necessary to partially modify or add a transition bracket to the bracket or the bridge according to the actual situation. A part of the pipe trench in the main tunnel of the power plant crosses the cable trench, which reduces the local height of the cable tunnel by half, the cable bracket cannot be installed, and the cable channel cannot meet the requirements of cable laying. This problem was solved by shortening the pitch of the cable support, and various types of transition brackets were also designed at the intersections in the main tunnel of the cable.
3.2 Cable entry into the cabinet and the entrance and exit of the cable shaft is also a difficult point of cable laying. It is also necessary to accurately calculate the number of cables at each disc and each shaft, and install it reasonably according to the calculation results and the actual situation on site. Transition bracket. The power plant is equipped with a cable ladder in the vertical direction at the upper panel of the cable mezzanine for use in the cable upper cabinet. At the bridge on the shaft, the shaft bracket is connected with the bridge by steel pipes to facilitate the entry and exit of the cable.
3.3 After the construction of the cable channel is completed, the secondary design of the cable is also completed at the same time, and the cable sectional view is drawn. In the case of the construction period, the high-voltage cable should be laid first, followed by the low-voltage power cable, and finally the control cable and signal cable. Try to avoid cross-construction of power cables and control cables. However, due to the construction period, it may be necessary to modify the secondary design in order to complete the image progress, and the secondary design should be modified to provide a passage for the subsequent cables.
3.4 Cable laying must be carried out according to the cable sectional view, according to the order in which the cables are arranged on the bridge and the bracket. If the secondary design is more accurate, then the cable should have little crossover. However, in the laying process, if some local parts do not conform to the secondary design or the cable is not good, the transition bracket should be added in time according to the actual situation. When the cable enters the cabinet or the pipe, if it is a cable bracket or ladder, the cable should be led down from the lower layer of the cable. If it is the bottom of the bridge, when the cable is less, the side of the bridge is opened. Holes are taken out; when there are many cables, it is considered to be led out in rows by the inside of the bridge.
3.5 The cable lashing work is to lay one and tie one in principle. After the cable is laid in place, the first end of the cable is trimmed back and forth. After the first binding, the cable can be shaped by wire and other materials. After the secondary finishing, the ligating material is replaced with a plastic wire and tied with a ruler.
4. Precautions during the construction process 13131636888
4.1 Before the cable is laid, check the cable thoroughly. The cable type, voltage and specifications should conform to the design. The cable should be in good condition, without damage and good insulation.
4.2 Check the cable layout, specifications and core number in the cable inventory according to the system wiring diagram, schematic diagram, wiring diagram of the panel, wiring diagram of the terminal box, etc.
4.3 According to the cable inventory, list the number, specification, starting point, end point, length and direction of each cable, and make a list according to the laying order for the actual laying.
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