A new simple low-shear capillary viscometer for blood¹

Article type: Research Article

Authors: Benis, A.M.^{; *}

Affiliations: Faculté de Médecine de Nancy, Physio-Pathologie Respiratoire, Nancy, France

Note: [1] Supported in part by French Government Grant D.G.R.S.T. 66-00-442.

Note: [*] Present address: Department of Chemical Engineering, Columbia University, New York.

Abstract: A simple and inexpensive low-shear capillary viscometer has been developed. It comprises a coiled plastic capillary 1 mm in dia. and 4–8 m long. A pressure difference is imposed on the capillary by means of a rubber air inflation bulb and is read on an ordinary manometer. The flow rate is measured by timing the blood meniscus between two divisions in a graduated tube. Use of a very long capillary allows one to attain very small shear rates while employing large pressure differences, thus ensuring that surface tension effects are negligible. The range of relative velocity (U¯=4Q˙/πD3, tube diameters/sec) is from 0.1 to 50 sec−1. The instrument requires a sample volume of less than 10 ml and its extreme simplicity, both in construction and operation, is emphasised. Theoretical analysis indicates that errors due to using a coiled capillary and operating under unsteady-state conditions are completely negligible.

DOI: 10.3233/BIR-1968-5402

Journal: Biorheology, vol. 5, no. 4, pp. 263-270, 1968