Permeameter Lea and Nurse

Figure 9.3. Pioneering designs of permeameters used to measure the Bneness of powders led to a widely used commercial instrument known as the Fisher Subsieve Sizer, a) The Lea and Nurse permeameter. b) The Gooden and Smith permeametcr used a column of fine sand as a standard resistance, c) The Fisher Subsieve Sizer uses a standpipe in a column of water to provide a constant pressure head.

The use of a capillary flow meter which can be calibrated theoretically is a useful feature of the Lea and Nurse permeameter but the presence of the 280 cm of capillary tube makes the equipment bulky for many laboratories. In later permeameters the capillary tube is replaced by a standard pneumatic resistance which has been calibrated using a flow meter for known characteristics. It should also be noted that if the use of the permeameter is restricted to samples of the same type of powder and equation 9.3... 

Constant flow rate permeameters 1.6.1 The Lea and Nurse permeameter... 

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See also in sourсe #XX -- [ ]

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