| 摘要 |
Concentration sensor for fibre suspension in a closed system. Measuring of the concentration in a closed system provides some difficulties. For example, friction variations in supports for the sensor and irregular movements of the fibre suspension may give serious disturbances of the measuring result. Through the present invention these disturbances have been eliminated. In a known way at the side of a suspension containing pipe (1) a niche (2) has been connected having an opening against the pipe. In the niche a rotatable stirrer and a not rotatable sensor have been arranged. The stirrer has its shaft preferably perpendicular against the pipe and near the opening of the niche. The sensor is located behind the stirrer in the niche. The stirrer is rotatable by means of a motor. The sensor has been elastically suspended so that it may be provided a tendency for turning. When the stirrer is rotating it will create a whirl of the suspension in the niche which whirl partly prevents the suspension in the pipe to freely flow into the niche, partly influences the sensor by means of a torque which mirrors the concentration of the suspension, which means that a higher concentration creates a higher torque. The torque of the sensor is measured by means of a shaft or three pins which extend out of the niche through elastic rubber bushings. |
