Application of a novel linkage design for the concentration sensing system

In industrial applications, copper wire is often used in the cable core or the motor armature. These copper wires are made by passing copper rods through the round-hole mold in a wire drawing machine. To reduce friction, it is necessary to use a lubricant mixed with oil and water for lubrication. The oil would be consumed over time, so it is required to add oil in a while to maintain lubrication. Generally, concentration sensors are used to monitor the concentration of lubricant to determine the timing of replenishing the oil. The principle of the sensor is by the intensity change of optical reflection to detect the concentration. However, copper chips scraped off from the wire during the drawing process will gradually accumulate on the surface of the sensor, thus causing sensor misdetection due to the shading of the light source. In this paper, an improved concentration sensing system is proposed to solve this problem. In the proposed system, a clean water tank is placed beside the oil tank, and the sensor is located in the clean water tank most of the time and is moved to the oil tank for measurement only at a specific time. After the measurement is completed, it will return to the clean water tank. This can greatly reduce the time the sensor is immersed in the oil tank, minimizing the chance that the sensor is shielded by copper scraps. To enable the sensor to move in this manner, a novel linkage design is proposed to meet several requirements in the movement of the mechanism. The mechanism is featured by its simple structure and only one driving device is needed. Furthermore, motion analyses of the mechanism are provided. Finally, we explain the working principle of the measurement system where the proposed linkage and the concentration sensing system are combined. To sum up the results, the proposed method can effectively expand the frequency of on-site maintenance from monthly to annual, which greatly reduces manpower requirements and effectively improves stability.