Installation, Requirements, Considerations

Installation

3. Installation

3.1 Requirements

To insure that a representative sample is being measured at all times, the solution must move through and completely purge out the cell channels or guard tube. If the measurement is made in a rapidly moving liquid, the existing circulation of the solution can be utilized by mounting the assembly as described in the next section so that the flow of the solution forces liquid through the cell. However, when measurements are to be made in quiescent solutions, means must be provided for forcing the solution through the conductivity cell so no air bubbles accumulate or care taken to place the cell in a position to measure the true value of the solution.

Do not use the cells in solutions which will attack the fittings used or the wetted cell materials. The PES and platinum or nickel of the electrode are the cell materials with which the solution will come into contact. The wetted materials of the removal device with which the process may come into contact with are CPVC, Teflon, EPDM and Viton.

Do not use the cell in a solution having temperatures greater than 80°C. The maximum limit set by the temperature compensator range must be observed.

For cells having a constant of 0.01, 0.1 or 1, make certain that the guard is in place and is not loose on the cell body. The guard tube must be hand-tightened only. There is a 1/16 inch space between the guard tube and the cell body.

Do not install the 4909 Assembly where pressures and/or temperatures may occur outside the operating range given in Fig. 1-1. Both pressure and temperature must be within the shaded area of the curve.

Avoid installations where the 4909 Assembly will be exposed to pressure shock caused by water hammer.

3.2 Location and Position

Refer to Fig. 3-1 or Fig. 3-2 for mounting dimensions.

Considerations

The cross-channel in the high constant cells or the guard tube holes in the low constant cells must be covered by the solution during measurements.

Vertical insertion (from above) or horizontal insertion can be used. Make certain the tank or pipeline is full under all process conditions. If a pipeline is not always full, use a vertical mounting and insert the cell far enough into the vertical pipe that the cross-channel is below the horizontal exit pipe which may empty out. Make certain an air bubble in the pipe does not prevent the cell from filling properly. (If the cell becomes dry after use, it may require cleaning in accordance with Section 4.1 before again being placed in service.)

For best results, whether vertical or horizontal mounting is used, position the cell so that the sample will flow through the channels or guard tube towards the mounting end of the cell, exiting through the cross- channel or guard-tube holes. In applications where vertical mounting is required, avoid a position with the cell channels pointed up, as this will permit solution to flow down into the open end of the cell and may result in clogging by solids settling in the cell channels.

Allow for insertion depth from the outside wall of the mounting surface as indicated by the dimensions in Fig. 3-1 or 3-2.

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4909 CPVC Conductivity Cell Insertion/Removal Assembly– Operations Manual