BS ISO 19051:2015 pdf free

BS ISO 19051:2015 pdf free.Rubber, raw natural, and rubber latex, natural
In the combustion process (furnace at ca.1 000 °C), nitrogen is converted to nitrogen gas/oxides. If other elements are present, they will also be converted to different combustion products. A variety of absorbents are used to remove these additional combustion products.
The combustion products are swept out of the combustion chamber by an inert carrier gas such as helium and passed over heated (about 600 °C) high purity copper. This copper can be situated at the base of the combustion chamber or in a separate furnace. The function of this copper is to remove any oxygen not consumed in the initial combustion and to convert any oxides of nitrogen to nitrogen gas.The gases are then passed through the absorbent traps.
The combustion section of the analyser is designed to achieve both complete combustion of the test piece and conversion of oxides of nitrogen to nitrogen gas (N2). Although different approaches have been chosen by different manufacturers, the use of high purity copper is universal for the reduction stage.
In some instruments, the combustion and reduction stages are housed in separate furnaces. In others, the reactions are combined in a single two-tier furnace. Catalysts are usually added to the combustion section to aid complete combustion along with absorbents to remove potential contaminants. Both the catalysts/absorbents and copper metal are packed into readily exchangeable tubes made of ceramic material or high quality silica.
The detection system within the analyser can take several forms depending on the combustion mode and test piece size. With small test pieces, the combustion gases can be separated on a GC column and quantified using a thermal conductivity detector. A schematic diagram of such a system is shown in Figure 1. If larger test pieces are required, an instrument employing “frontal” chromatography can be chosen. The latter approach employs a GC column with thermal conductivity detection but provides a step-wise profile for integration. Other detection approaches do not require a separation step but use separate infrared and thermal conductivity cells to respond to individual elements.BS ISO 19051 pdf download.