Instruction Manual
D200099X012
249 Caged Sensors
April 2017
5
The displacer in this unit is a sealed container. If penetrated by process pressure or liquid, the displacer may hold pressure
or hazardous liquid for an extended period. A displacer that has been penetrated by process pressure or liquid may contain:
pressure as a result of being in a pressurized vessel
liquid that becomes pressurized due to a change in temperature
liquid that is flammable, hazardous or corrosive
Sudden release of pressure, contact with hazardous liquid, fire, or explosion, which might result in personal injury or
property damage, can occur if a displacer that is retaining pressure or process liquid is punctured, subjected to heat, or
repaired.
Handle the displacer with care. Consider the characteristics of the specific process liquid in use.
Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
Note
Except for gaskets (keys 13 and 14), trouble symptoms peculiar to specific parts are discussed in the following sections. Each
section is specific to these parts. Regardless of location, gasket failure is indicated by leakage in the gasket area. Every time a
gasket is removed, replace it with a new one upon reassembly.
The procedures below apply to all sensor types except where indicated. Key numbers used are shown in the following
illustrations:
249—figure 8
249B—figure 9
249C—figure 10
249K—figure 11
249L—figure 12
Cleaning the Cage
Process residue buildup in the bottom of the cage (key 1) or at the connections may restrict flow in and out of the cage
or interfere with displacer motion. Remove the cage to clean out process residue buildup.
1. Before starting any maintenance procedure, be sure the following safety actions have been completed.
Relieve process pressure in the vessel where the 249 sensor is installed.
Drain the process liquid from the vessel.
Shut off any electrical or pneumatic input to the controller or transmitter attached to the 249 sensor and vent
any pneumatic supply pressure. Remove the controller or transmitter from the torque tube arm (key 3). Take
care not to damage the torque tube assembly (key 9) inside the torque tube arm.
Be sure the cage is also free of process pressure and/or liquid. Use caution when loosening flange bolting (key 22)
or pipe plugs (keys 17, 26, or 27).
Be sure process pressure or liquids have not penetrated the displacer (key 10).
2. Properly support the cage head (key 2) and the torque tube arm. Remove the cap screws or stud bolts (key 21) and
hex nuts (key 22) that hold the cage head to the cage.
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