5 mL – 23 mL, 250 °C, 1800 psig
The 4749 is a 23 mL, general purpose acid digestion vessel, similar to the original 4745 model but modified for use at higher temperatures and pressures, and provided with safety blowout protection as well. Operating temperatures and pressures up to a maximum of 250 °C and 1800 psig are permitted in this vessel using a thick-walled PTFE liner with a broad, flanged seal. The forces required to seal the liner are developed by tightening the vessel cap with a spanner while holding the vessel in a special fixture. A blow-off disc in the vessel head is designed to blow out and release the pressure through an opening in the cover at approximately 3500 psig. With its high temperature capability and blow-off disc this is an excellent vessel for all general digestion purposes, and particularly for experimental procedures in which the behavior of the reactants has not been well established.
One of the original applications for these vessels, which continues to be one of their principal uses, is for digesting alumina samples at temperatures to 250 °C. For this and other difficult digestions, Parr offers an optional tumbling ring (A284AC) that can be attached to the vessel body. With this ring in place, the vessel will roll smoothly when placed on a powered roller, thus providing a convenient means for agitating the charge during long digestion procedures.
The 4749A to 4749D Vessels incorporate PTFE liners with reduced volumes. The liners are offered with the associated cover in 5, 6, 10, and 11 mL versions. Both wide and deep configurations are available. The profile of these reduced volume liners are shown in the following illustrations. These reduced volume vessels may be a good choice for analysts working with expensive or scarce materials. It may also appeal to users who wish to minimize risks associated with hazardous materials or reactions by limiting the amount of reactants used. These reduced volume vessels also minimize the quantity of reaction products which may require special disposal procedures.
Accessories such as the spanner wrench, holding fixture and tumbling ring are not included with these vessels and must be ordered separately.