Instruction Manual

Instruction Manual

D102803X012

249W Sensor

December 2012

CAUTION

If the displacer is to be disconnected from the displacer rod/driver assembly before being removed from the process vessel

or displacer cage, provide a suitable means of supporting the displacer to prevent it from dropping into the vessel or cage

and being damaged.

1. After following the proper procedure to remove the sensor and the displacer from the process vessel or displacer

cage, move the sensor assembly to a suitable maintenance area. Support the assembly to avoid damage to the

displacer, displacer stem, displacer rod assembly, and associated parts.

2. Remove the controller/transmitter and displacer (key 4). Then, remove the hex nuts (key 20) that hold the torque

tube arm (key 2) to the wafer body (key 1). Separate the torque tube arm from the wafer body.

3. Remove the nuts (key 18) and retaining flange (key 14) at the end of the torque tube arm.

4. Remove the positioning plate (key 15) by freeing its two lugs.

The vertical lug fits into a hole in the flange of the torque tube arm (top of figure 13, left). The horizontal lug (hidden

behind the screwdriver at the bottom of figure 13, left) fits into a slot in the outer tube end of the torque tube

assembly (the figure 13 exploded view shows this lug to the right of the outer tube end).

Place a screwdriver blade in the slots of the positioning plate and outer tube end as shown in figure 13. Slowly turn

the positioning plate to release its lug from the torque tube arm. Then carefully turn the plate back to allow the

displacer to come to rest, and slip the other lug of the plate from its slot in the outer tube end.

5. Pull the torque tube assembly out of the torque tube arm. Remove the tube end gasket (key 13) and discard (a new

gasket will be installed in step 9). Clean and inspect the gasket mating surfaces.

6. Using the proper tool, loosen and then remove the upper bearing driver bolt (key 8). Lift the displacer rod/driver

assembly from the knife edge of the driver bearing (key 7).

7. Visually inspect the bearing driver for corrosion or wear. If replacement is necessary, remove the bearing driver by

removing the lower bearing driver bolt. Install a new bearing driver and the lower bearing driver bolt.

8. Install the new displacer rod/driver assembly on the knife edge of the bearing driver. Install the upper bearing driver

bolt (key 8), but do not tighten.

9. Insert new tube end gasket into the recess in torque tube arm.

10. Insert the torque tube arm assembly and rotate until its socket mates with the displacer rod assembly and so that

the outer tube flange rests against the gasket.

11. With a thumb on the upper portion of the positioning plate and screwdriver in the slots as shown in figure 13,

rotate the plate and press the lug on the plate into the hole in the torque tube arm (this will preload the torque

tube).

12. Install the retaining flange and secure it with four nuts (key 18), being sure to tighten all nuts evenly.

13. Tighten the upper bearing driver bolt (key 8). It will be necessary to put slight pressure on the displacer rod/driver

assembly to access the upper bearing driver bolt.

14. Install the torque tube arm on the wafer body and secure it with the proper bolting (keys 19 and 20).

15. Install the sensor and controller/transmitter. Calibrate the controller/transmitter following the procedures given in

the controller/transmitter instruction manual.

Replacing the Torque Tube

Corrosion or leakage through the outer end of the torque tube is evidence of deterioration in the torque tube

assembly (key 3) or torque tube end gasket (key 13). Erratic or nonexistent rotary shaft output may occur if the socket

on the inner end of the torque tube assembly does not engage the bearing end of the displacer rod/driver assembly

(key 5).