Integrated Solution of Power Supply and Water Supply for Mobile Bulk Yard Machinery

In the process of material handling, dust will be inevitably produced by the mobile bulk yard machinery, and this is criticized for the increasing requirements of environmental protection currently. The equipment managers have been using methods such as dry method, dry mist or spraying method to cloud vacuum or press dust, but due to problems in cost, environment, technology and many other aspects, the above methods have not been used normally. At present, the issue of environmental protection has been upgraded to an issue related to the people's livelihood, which has received great attention from the state. Dust generated by the materials on mobile bulk yard machinery must be effectively dealt with. Due to the high investment cost and use cost and high failure rate of dry dust removal, general users will not accept it. Although dry mist and spraying methods are feasible dust control methods, they need to rely on water resources to solve the problem of water supply on the machine, which must be realized with the help of external equipment. This article discusses the power supply problem while discussing the water supply method, which is helpful to analyze the advantages and disadvantages of each solution.

1. Solution to power supply and water supply for mobile bulk yard machinery

There are three kinds of power supply and water supply solutions for mobile bulk yard machinery: cable reel + water cable drum, cable reel + ground water tank, and integrated power supply and water supply with drag chain.

1.1 Solution to power supply with cable drum reel + water supply with water cable reel (drum)

In this solution, the mobile equipment is supplied power and water through cable reels and water cable reels (drums) respectively. These two systems are relatively independent. Power supply with cable reel is a conventional method for power supply. If the cable adopts the form of two-in-one or three-in-one, only one cable reel is required; if the power and control are separated, there are power reels and control reels respectively. If the equipment traveling distance is not long, the water cable reel can be used for water supply; if the equipment traveling distance is long, the water cable drum is needed for water supply. In terms of the overall solution of power supply and water supply, this method requires sufficient installation space on the machine. There are also many ways to drive the reel, such as hysteresis, torque motor, and frequency conversion ways, which involves many parts, including motor, reducer, coupling, slip ring box and optical cable coupler, which also means more failure points. In addition, the cable and water cable need to be maintained a certain tension in the coiling process. Otherwise, in cold seasons and regions, the cable or water cable is easy to be fractured.

1.2 Solution to power supply with cable reel + water supply with ground water tank

In this solution, the mobile equipment is supplied power and water through cable reels and ground water tanks respectively. These two systems are relatively independent. The power supply method of the cable reel is the same as that in Section 1.1. According to customer requirements, power / control cable reel or two-in-one / three-in-one cable reel is used for power supply. This part of the cable may be affected by seasons and regions, resulting in cable fracture. The water supply method in this solution adopts ground water tanks, which is more conducive to continuous water supply than the water cable reel method, but there is a sealing problem of the water tank. Since there are dust particles floating in the atmosphere at the scene, they are likely to fall into the tank, and over a long time, the dust will accumulate and is more difficult to clean. In cold seasons and regions, the heat preservation of the water tank is also a problem, and it is necessary to avoid the problem of water freezing when the temperature is below 0℃. In addition, it is also faced with the adaptability of foundation settlement.

1.3 Integrated solution of power supply and water supply with drag chain system

This solution is to integrate the power supply and water supply of the equipment into one by using a set of drag chain system. As we all know, the drag chain system originated in the machine tool industry as a mobile power supply method. As a machine tool accessory, the drag chain product made of engineering plastics is designed and produced to protect the pipelines of different media required by various moving mechanisms of machine tools. As the functions of engineering-plastic drag chain are recognized and various advantages are found, the drag chain system today is found in almost all walks of life, such as crane, metallurgy, shipbuilding, automobile, entertainment, logistics, automation, aerospace, energy, and marine engineering. Compared with the traditional mobile power supply system such as festoon, drum and sliding wire, the unique advantage of the drag chain system is that it can integrate all kinds of media and needs to achieve all requirements. Whether it is high pressure, low pressure, control, data, optical cable or water pipe, gas pipe and hydraulic pipe, all functions can be achieved through one system.

The drag chain system itself does not need power, and there is no driving mechanism. The drag chain is driven by the power of the traveling mechanism, so there is no need to consider the installation of the equipment. At the same time, it has better protection for cables and water cables, which improves the reliability of power supply and water supply, reduces maintenance downtime caused by failure and improves equipment utilization. On the other hand, the tow chain system is easy to be maintained with less workload. The drag chain system eliminates the need for two-in-one or three-in-one cables, greatly reducing the risk and cost of cable replacement. Of course, if there is more equipment on the track, the space that needs to be arranged will be larger, which is the disadvantage of the drag chain system.

With the development of automation technology, more and more terminals are realizing or preparing to realize automation, which requires equipment-related accessories or mechanisms to have high reliability, less maintenance workload and good controllability. The drag chain system can also use PPDS and other functions to monitor the running state of the drag chain in real time.

Many years ago, an integrated solution of power supply and water supply was provided for a coal terminal of a foreign power plant. The drag chain system for power supply and water supply of this equipment not only includes water pipes, but also power cables, control cables and optical cables. After more than 10 years of use, it still has high reliability and less maintenance workload. The customer is very satisfied with this integrated solution, and all equipment of the subsequent terminals adopts this integrated solution.

2. Comparison of three solutions to power supply and water supply for mobile bulk yard machinery

  The above three solutions have their own advantages and disadvantages. Customers need to choose the most appropriate solution according to their own situation with overall consideration of various factors. See the following table for the advantages and disadvantages of the three solutions

3. Conclusion

The environmental protection situation is becoming more and more severe, and the water supply of mobile bulk yard equipment has become indispensable. Based on the above analysis, the integrated solution of power supply with the drag chain system is better. In the life cycle of the equipment, its cost is the lowest, the reliability is the highest, and the maintenance is the least. It is hoped that users can fully consider these key indicators when choosing a solution and make the right choice.

Abstract: Hoisting and Conveying Machinery

July 2018