The method involves slowly lifting a ring, often made of platinum, from the surface of a liquid. The measurement is performed with a force tensiometer , which typically uses an electrobalance to measure the excess force caused by the liquid being pulled up and automatically calculates and displays the surface tension corresponding to the force. Earlier, torsion wire balances were commonly used. The maximum force is used for the calculations, and empirically determined correction factors are required to remove the effect caused by the finite diameter of the ring:. The most common correction factors include those by Zuidema and Waters for liquids with low interfacial tension , Huh and Mason which covers a wider range than Zuidema-Waters , and Harkins and Jordan more precise than Huh-Mason while still covering the most widely used liquids.
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Simply enter the quantity you want to purchase and the current availability will appear below the item. Platinum-iridium ring has a mean circumference of 6 cm. Ring has stirrup with parallel sides 25 mm high. Exact circumference and rates of the ring and wire radii are provided. Hardwood cylinder protects ring when not in use.
Enameled metal housing is mounted on tripod base with leveling screws; overall mm x mm x mm high. Unit comes completely assembled with torsion wire, 6 cm platinum-iridium ring, metal case and instructions. Shipping weight: 27 lbs. Don't have a web profile? Create one now. Log In or Create a Profile. Check Out. View Shopping Cart. Search term is required. Cell Expression NEW!
Gene Expression NEW! Not yet rated. Request A Web Profile. Description Provides precise readings of upward interfacial and surface tensions by the ring method to values reproducible within 0. NOTE: prices may vary due to frequent changes in the cost of platinum. Qty Ascending Descending.
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This test is performed by pulling the ring upward through the surface of the liquid. The force needed for the ring to break the surface overcome the surface tension is determined. There are applications where the surface tension at the boundary of two liquids needs to be measured. This is called interfacial surface tension. The Tensiometer for this test needs to pull the ring up through the boundary between the lower, higher density liquid, and the liquid that is floating above. The force needed to break through the surface of the higher density liquid is recorded as interfacial surface tension.
Du Noüy ring method
The proven instrument for measuring surface tension - quickly - 15 - 30 seconds! Ideal for checking liquids, including oils, detergents, serums, colloidal suspensions, chemicals and other products. Unit comes completely assembled with torsion wire, platinum-iridium ring. Includes metal case and instructions. Ship wt. Graduated dial reads in both directions from zero and a double vernier is provided.