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2811 Pellet Press

Pellet Press Bulletin - 28323 The Parr Pellet Press

Restricted burning rates. Some materials have dan-gerously high burning rates if burned as a loose powder. These rates can be restricted to safe levels by compressing the powder into a pellet or briquette. Six Pellet Sizes The pellets produced in theParr press are cylindrical in shape with flat ends. Their height or thickness depends upon the amount of material compressed and the force applied. Six different punch and die sets are available for making pellets in diameters from 3 mm up to a maximum of 1/2 inch. All of these punch and die sets operate in the same basic press. The dies are not fastened down. They auto- matically align with the punch and may be slipped out from under the punch for quick reloading.
Complete combustion. Loose powders exposed tothe turbulent gases produced during a bomb combustion may be blown out of the sam- ple cup and extinguished by the cold bomb wall before they have burned completely. A pel- letized sample will be held in the combustion zone with a much better chance for com- plete combustion. TheParr 2811 Pellet Pressprovides a convenient means for compressing powdered materials into pellet or tablet form without a heavy invest- ment in expensive tablet-mak- ing machinery.It is a compact, hand-operated press that can be used anywhere in the labo- ratory,requiring very little bench space and no fixed mounting, producing uniform pellets in a polished stainless steel die and ejecting them smoothly into a stainless receiver without danger of con- tamination.
Ease of handling. Pelletized samples are easyto handle and weigh; they lie flat in the combustion capsule and ignite easily. Pressure and Density Adjustments The compressive force inthis press is developed by hand pressure on a lever attached to alarge steel cam. This system is designed to provide a steadily increasing mechanical advantage up to a ratio of approximately 50 to 1 at the end of the stroke. Thus, a force of 20 pounds applied to the lever develops approximately 1000 pounds on the punch, which is adequate to produce firm pellets from most pow- dered materials, usually with- out adding a binder.The anvil which supports thedie in the Parr press is attached to a heavy screw post so that it can be raised or lowered. Rotating the anvil to raise or For Other Test Procedures Pelletized samples areequally important in other investigative and test proce- dures. Laboratories engaged in pharmaceutical, biological, nutrition and spectrographic operations find frequent uses for tablets and wafers of the types that can be made in a Parr press. Spectroscopists find this device excellent for preparing samples to be ana- lyzed in an emission spectrom- eter.Small diameter pellets made in a Parr pellet press can be imbedded in a hole drilled in the sparking elec- trode, assuring the operator that his sample will always be held in exactly the right posi- tion for best results. For Bomb Calorimetry Pellet making is a veryimportant step in bomb calorimetry, particularly when working with finely powdered samples. Although some pow- dered materials burn well in an oxygen bomb, others, such as benzoic acid, must be pelletized for safe combustion and best results. There are several advantages to be gained by burning samples in pellet forminstead of a loose powder.
Parr Instrument Company