Flat Sheet CMSM

Flat sheet CMSMs are masked with adhesive backed aluminum tape to prepare them for testing. Figure 5.13 shows the cross-section of the masked film in a permeation cell with a detailed view of the masked film The membrane sample is sandwiched between two pieces of 1-5/8 in. aluminum tape. The piece of the tape used for the upstream side of the membrane had a 1/2 in. diameter hole cut out of the center while the center used for the down stream side of the membrane had a 5/8 in. diameter hole in the center. The larger hole on the downstream side of the membrane is used to provide a more accurate measurement of the area that is based on the smaller hole on the upstream side only. This precaution is necessary to prevent the holes of the two sides of the mask from being ahgned visually. Once the membrane is sandwiched in the aluminum tape, the sample is ready to be masked onto the permeation cell. 

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