New Generation Rotary Consistency Transmitter, 2005 Engineering, Pulping & Environmental Conference

The basic design of rotating consistency transmitters has remained the same over 40 years. The structure contains a squirrel cage motor which rotates a sensing element inside a process pipe through a drive belt. Over that period only electronics has been modernized, partly perforce because of obsolete components, partly to improve performance.

The drawbacks of the old design are related to installation and maintenance. Massive structure requires pipe expan-sions for less than 12" pipes, the motors are 3-phase motors and need high voltage supply with contactors and over-load protectors, drive belt wears and is a maintenance item, for service a user has to wait a stoppage and drain the line before removing the sensor.

In the new design by Kajaani Process Measurements Ltd. the squirrel cage motor is replaced with a direct drive servo motor which is integrated with the drive shaft. This has resulted in drastically smaller size, 60 % lower weight, and elimination of wearing drive belt and 3-phase high voltage in the sensor.

Perhaps the most important feature of the new KC/5 sensor is that it can be inserted in and removed from the process while process is running. The small size makes it possible to install the sensor through a gate valve.