Baker Hughes Pneumatic Level Transmitter 12820

Relay (See Figure 10) Metering Orifice

The Metering Orifice for the Nozzle air supply is fitted with a clean-out plunger which forces a small wire through the jewel orifice.

Disassembly: The Metering Orifice can be removed for cleaning while the Relay remains fastened to the Air Manifold. If further disassembly is required, proceed as follows: 1. Unscrew Mounting Screws which hold Relay to Air Manifold. Break joint carefully to avoid damaging the Relay Gasket.

2. Remove Metering Orifice Body and Retainer Screw and drop Relay Plug and Plug Spring from Relay Body. Remove six screws which hold End Plate, Intermediate plate and Diaphragms to Relay Body. Remove Diaphragm Spring from Relay Body and disassemble Diaphragm Block from Intermediate Plate.

3. Clean parts with clean soft cloth. Use solvent if oil and grease are present. Blow out ports in Body, Intermediate Plate, and End Plate with clean dry air.

Assembly: 1. Assemble Diaphragm Block in Intermediate Plate as shown in Figure 10.

2. Replace Diaphragm Spring in Relay Body. Align holes in Diaphragms with those in Intermediate Plate and End Plate and insert screws. Then assemble on Relay Body. The correct alignment of Intermediate Plate and End Plate on Relay Body is simplified by the use of reference marks.

3 .Assemble Relay Plug, Plug Spring, Retainer Screw, and Metering Orifice.

4. Position the Relay Gasket on Air Manifold. After establishing correct position, slip Relay Gasket over the two Mounting Screws on Relay and fasten Relay to Air Manifold.

To Clean: Shut off air supply.

Disconnect Nozzle Tubing from Air Manifold. Loosen Set Screw securing Nozzle in Nozzle Bracket and withdraw Nozzle.

Diameter of Nozzle hole is .020 (No. 76 drill). Push drill or wire of smaller diameter through hole. Blow out tubing with clean, dry air.

Replace Nozzle in Nozzle Bracket. Hold Nozzle firmly against shoulder in Nozzle Bracket and tighten Set Screw. Connect tubing to Air Manifold.;

Instrument Case Mounting (See Figure 10)

Standard case mounting is left hand; i.e., with Case to left of Displacer. Right hand mounting is optional. To reverse case mounting in the field, proceed as follows: 1. Remove Torque Arm from Protective Housing as outlined in Steps 1 through 3, previous paragraph.

2. Detach Torque Tube Housing Assembly from Protective Housing Assembly by removing stud nuts.

3. Attach Torque Tube Housing Assembly on opposite side of Protective Housing Assembly.

4. Reassemble Torque Arm, Protective Housing Flange, and Top Flange.

5. Disconnect Control Link from Reversing Arc.

6. Loosen Nut securing Reversing Arc. Turn Reversing Arc over and replace Nut. Before tightening Nut, however, be sure Arc is positioned so that tabs line up with slots (arrow on Reversing Arc should point toward Displacer).

7. Connect Control Link for desired control action and specific gravity.

8. Check Control Setting Scale to see that it agrees with control action. If necessary, reverse scale and knob plate.;

Displacer (See Figure 9) To Remove: On chamber type models, close stop valves in connecting lines and drain Chamber before disassembly. The procedure for disassembly is as follows: 1. Remove Top Flange and Protective Housing Flange.

2. Depress Torque Arm and unhook Displacer. On Chamber type models, allow the Displacer to rest at the bottom of the Chamber. On top flange mounted internal displacer type models, the Displacer must be suspended in the tank with the hanger below the Torque Arm. A simple hook made of 1/8” round stock will greatly facilitate unhooking the Displacer. The hook may be inserted in one of the holes in the Hanger.

3. Detach Torque Arm from Torque Tube Plate by removing screws and withdraw Torque Arm from Chamber.

4. Lift Displacer from Chamber or tank.

To Replace: Reverse above procedure.;

Resistance Unit (See Figure 11)

On Model 12810 proportional-reset controllers, the Resistance Unit may require occasional cleaning.

Disassembly: 1. Turn Reset Knob counterclockwise and lift Reset Pointer so that it clears stop on the Reset Dial.

2. Unscrew Reset Knob to end of thread and remove.

3. Use wrench on hex of Resistance Unit body and turn counterclockwise to end of thread.

4. Pull Resistance Unit Body from Frame with twisting motion to overcome friction of O-Ring.

5. Unscrew Spring Retainer from Body and remove Spring, Spring Button, Plug, and O-Ring.

6. Blow out ports and wipe parts with clean, lint-free cloth.

Assembly: 1. Reassemble Spring Retainer, Spring, Spring Button, Plug, and O-Ring on Body.