Emerson 249P Manual de Instruções descarregar pdf (Página 9)

Instruction Manual

D200100X012

249 Cageless Sensors

December 2012

2. Remove the controller/transmitter and displacer (key 10). Then, remove the hex nuts (key 20) that hold the torque

tube arm (key 3) to the sensor head (key 2). Separate the torque tube arm from the sensor head.

3. Remove the nuts (key 18) and retaining flange (key 6) holding the positioning plate (key 8) at the end of the torque

tube arm.

CAUTION

If the displacer is still attached to the displacer rod at this point, be careful not to let the torque tube assembly slip when

using the screwdriver leverage procedure in steps 4 and 6. Sudden release of the displacer could cause damage.

4. Remove the positioning plate (key 8) by freeing its two lugs.

The vertical lug fits into a hole in the flange of the torque tube arm (top of figure 4). The horizontal lug (hidden

behind the screwdriver at the bottom of figure 4) fits into a slot in the outer tube end of the torque tube assembly

(the figure 4 exploded view shows this lug to the right of the outer tube end).

The positioning plate may be pried away from the torque tube arm and outer tube end if the displacer already has

been disconnected from the displacer rod. However, if the displacer is still connected to the displacer rod, place a

screwdriver blade in the slots of the positioning plate and outer tube end as shown in figure 4. 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 and tube end gasket out of the torque tube arm. Remove the tube end gasket

(key 14) and discard (a new gasket will be installed in step 6). Clean and inspect the gasket mating surfaces.

6. Insert new tube end gasket into recess in torque tube arm.

7. Insert the torque tube assembly into the torque tube arm as shown in figure 4. Rotate the torque tube assembly

until its socket mates with the driver member on the displacer rod assembly and so the outer tube flange rests

against the gasket. With a thumb on the upper portion of the positioning plate and a screwdriver in the slots as

shown in figure 4, rotate the plate and press the lug on the plate into the hole in the torque tube arm (this will

preload the torque tube).

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

9. Install the sensor head and controller/transmitter. Calibrate the controller/transmitter following the procedures

given in the controller/transmitter instruction manual.

Replacing the Torque Tube Arm and Changing the Mounting

Looseness of the driver bearing (key 4), wear on its knife‐edged surface, or a bent, worn, or corroded displacer rod

assembly (key 7) may impair performance. Be especially sure to check the ball on the displacer rod.

1. After following the proper procedure to remove the sensor head and the displacer from the process vessel, move

the sensor assembly to a suitable maintenance area.

CAUTION

Support the sensor assembly to avoid damage to the displacer, displacer stem, displacer rod assembly, and associated

parts.

2. Remove the controller/transmitter and displacer (key 10). Then, remove the hex nuts (key 20) that hold the torque

tube arm (key 3) to the sensor head (key 2). Separate the torque tube arm from the sensor head.

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Emerson 249P Manual de Instruções Página 9