Preface

Those years as the increasing pressure by national control for environmental protection, government requires more and more strictly for dust-cleaning devices closed silos, tanks in mining industry. All stock grounds need to update into large tanks, so the level measurement requirements of such tanks is becoming more and more. Based on this, we designed and offered below solution of feeding for one raw coal tank in Gansu province. 

1. Project overview

This project is feeding system for material silos, the hardware we used Siemens PLC control module, IPC and Radar level sensors; the software we used Siemens programming software and its configuration software of WINCC7.0 version. The details as follows:

General process of feeding method is using conveyor with distributors. Adding 5 distributors on each conveyor in order to reach the uniform feeding of materials. Each distributor coupled with a radar level sensor at close position. And the distributors are controlled by the radar sensors. During the feeding procedure, radar sensors detect the feeding continuously. PLC is working by the signal output of radar level sensor(4-20mA), it judges the feeding max limit of distributor and stop it when it reaches max. and so on until the last feeding point ends.

2. Final solution and main ideas for this design

The automation control target of this project is operated on IPC by operator. Press the start button on the screen, system will judge the level data of each level sensors and give order to each distributor to finish feeding by sequences. When the main conveyor is started, the 1^st distributor will turns downward and be ready to feed for the 1^st feeding point, when it finishes the level settled the 1^st distributor will turns up and the 2^nd distributor will go down. Thus the material will pass the 1^st feeding point and be kept at the 2^nd distributor , it will feed the 2^nd feeding point. Through control like this way, after all distributors finish working, all feeding points will be fed to the level preset. System will stop the machine, the conveyor will empty the materials on it and stop loading.

In order to ensure the time and quantity of project construction, our company sent the experienced technique to participate in this project with license, communicate with field contact persons and done every job very well.

3. Devices and documents 

1. Devices list:

2. Documents:

2.1 operation manual

2.2 instructions of radar level sensor and maintenance instructions

2.3 party B provide training for workers of party A

4. Standards

GBJ147－90  Electrical installation works Specification for construction and

acceptance of low voltage electrical appliances.

GB50150－91  Electrical installation works Electrical equipment handover test standard.

GB50169－92  Electrical installation works Specification for construction and acceptance of grounding devices.

ZE-1.12-2003  Lightning protection grounding device and electrical grounding device construction technology.

JGJ46-2005    Technical specification for temporary electricity safety in construction site.

GB50231-98    General specification for construction and acceptance of mechanical equipment installation works.

5. Field photos