Emerson 141, 142 Maintenance, Cleaning the Sensor, Checking Model 140 Retraction Restraint

MODEL 140,141, and 142 sensors MAINTENANCE

MAINTENANCE

CLEANING THE SENSOR

Use a warm detergent solution and a soft brush or pipe cleaner to remove oil and scale. Isopropyl alcohol can also be used to remove oily films. Avoid using strong mineral acids to clean conductivity sensors.

CHECKING MODEL 140 RETRACTION RESTRAINT

The integrity of the Model 140 will become compromised is the flared tip of the electrode is allowed to blow out against the compression fitting body. In the even a blowout occurs, replace the sensor.

REPLACING MODEL 140 SENSOR SEAL.

If the process seal is leaking owing to a pitted or uneven sensor tube, a replacement sensor is required. If the sensor tube surface is smooth and clean yet the process seal is leaking, the process O-ring is damaged and requires replace- ment according to the following procedure (see Figure 2). Replacement parts can be obtained from the Process Fitting Rebuild Kit (PN 23731-00).

1.The junction box with attached compression fitting body, nut and compression fitting must be recovered from the sensor for reuse. Unscrew the junction box cover and set aside. Mark and disconnect the electrical connections from the terminal block. Remove the junction box compression fitting nut from the compression fitting body and separate the junction box from the sensor tube.

2.Remove the nylon ferrule and snap ring (discard both). Remove and save the junction box compression fitting nut.

3.Slide off the sensor compression fitting nut and set aside for reuse. Slide off the remaining PEEK ferrule and split ring (discard both).

4.Remove the sensor compression fitting body and replace the Viton O-ring. Lubricate the O-ring with the barium based lubricant provided.

5.Wrap the threads of the sensor compression fitting body with pipe tape and slide the body on to the sensor tube.

6.Slide on a new PEEK ferrule, beveled side facing the electrode tip, and a new PEEK split ring, flared end towards electrode tip. Slide on the sensor compression fitting nut and thread it onto the compression fitting body. Finger tighten.

7.Reinstall the J-box on the sensor tube. Finger tighten the J-box compression fitting nut. Use a wrench to turn the nut a 1/4 to 1/2 additional turn.

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