July 14th, 2014
Saint-Gobain Seals’ Rulon® 123 fluoropolymer material was recently qualified in a metering pump application for a renowned gasoline pump manufacturer in Europe. Metering pumps are used to deliver or meter fluids; in the case of metering, a precise delivery rate is required and one of the special attributes of metering pumps is high metering accuracy.
Because metering pumps require accurate and controlled leakage behavior as well as very long life with constant performance, the piston cup seal made out of their Rulon® 123 tape is ideal for this application as it provides the required flexibility and controlled sealing of the flow pump. The high-performance qualities are due to the custom, engineered design and the material being manufactured with an innovative production process. Low friction and wear as well as a wide range of chemical resistance against aggressive substances in motor fuels finalize the performance package. After the completion of extensive life time testing including infield applications, the Rulon® 123 cup seal was approved for use in these gasoline metering pumps.
Federal institutions all over the world have established specifications, tolerances, and other technical requirements for liquid measuring devices to control the accuracy of fuel pump measurements, which makes the sealing function a critical component regarding accuracy and long operative condition. According to the European directive 2004/22/EC for fuel metrology Measuring Instruments Directive (MID), the tolerance range is no more than +/- 0,5%, which leads to a high level of precision for the fuel pump to fulfill these requirements. In the United States, the measurements from the National Institute of Standards and Technology (NIST) are more stringent than Europe, specifying the accuracy of the tolerance range to +/- 0,3%.
Rulon® 123 material is part of Saint-Gobain Seals’ polymers product line and operates extremely well against soft mating surfaces, has excellent wear resistance, is non-abrasive and has one of the lowest coefficient of friction of most reinforced PTFE materials. The Rulon® brand consists of a family of proprietary, homogeneous materials that are mostly composed of PTFE based resins, and products include bearings, rings, tapes, formed parts, basic shapes and wear components.
Primarily used in mechanical, electrical and chemical applications, Rulon® material withstands a variety of harsh environments such as extreme dryness, cryogenic temperatures, water, steam and hydrocarbon fuel. Aside from the above gasoline metering pump for the automotive industry, Rulon® 1439 material is being utilized in the Life Sciences industry on another type of metering pump - a kidney dialysis system. Other applications include bearings and components in chemical analyzer systems and harmonic scalpels, ball bearings on the NASA rover Curiosity that was launched to Mars, and sliding elements on the bogie of the newest 7000 series trains in the Washington DC metropolitan area.