Abstract: A graphite crucible has a cylindrical body with an upper opening for receiving a sample for analysis and a disk-shaped pedestal base. The pedestal base includes a bottom surface with a centrally formed circular indentation. An inwardly projecting concave arcuate annular indentation extends between the body and pedestal base with a smoothly curved radius of curvature. The upper and lower walls of the arcuate indentation diverge outwardly at an angle of from about 56 to about 60°. The pedestal base includes a bottom surface with a centrally formed circular indentation.

Abstract: A resistance furnace provides an improved upper and lower electrode construction with significantly increased coolant flow. The lower electrode has a tip design that significantly lowers the electrode tip temperature during an analysis. The upper and lower electrodes also cooperate with an improved crucible design to significantly reduce the power required to fuse a specimen contained in the crucible. The furnace uniformly heats the floor and lower side walls of a crucible, which lowers the power requirement for specimen fusion and provides higher structural benefits to provide consistent analysis and manufacturing yields. The crucible has a cylindrical body and pedestal base with an annular smoothly curved concave indentation therebetween.

Abstract: A combustion tube comprises a generally cylindrical body with an outwardly extending annular tube stop spaced from one end of the combustion tube for engaging a combustion tube mounting assembly and fixing the tube in a precise position. Near the opposite end of the tube is an enlarged opening for receiving an upper seal assembly of a combustion furnace with the outer annular shoulder of the upper end of the tube having a rolled edge to facilitate the insertion of the tube through the seal in the upper seal assembly of the furnace. The combustion tube is made of quartz glass to withstand the temperatures encountered in the furnace. The combustion tube is specifically designed and adapted to be precisely positioned in an induction furnace with an easy tube removal system for the furnace.

Abstract: A crucible handling shuttle includes a pair of opposed dual crucible-gripping arms mounted on a rotatable head and moves between an induction furnace pedestal and a crucible loading station, such that one pair of arms pick up a crucible loaded with a preweighed sample, the shuttle moves to the induction furnace, where the other pair of arms grip and remove a spent crucible. The shutter head then rotates to deposit the new sample-holding crucible onto the pedestal and subsequently moves out of the furnace area to a sample disposal chute positioned between the crucible loading station and the furnace, whereupon the spent crucible is dropped for disposal. The shuttle head is then rotated and moved to the loading station to pick up a new crucible.

Abstract: A crucible handling shuttle includes a pair of opposed dual crucible-gripping arms mounted on a rotatable head and moves between an induction furnace pedestal and a crucible loading station, such that one pair of arms pick up a crucible loaded with a preweighed sample, the shuttle moves to the induction furnace, where the other pair of arms grip and remove a spent crucible. The shutter head then rotates to deposit the new sample-holding crucible onto the pedestal and subsequently moves out of the furnace area to a sample disposal chute positioned between the crucible loading station and the furnace, whereupon the spent crucible is dropped for disposal. The shuttle head is then rotated and moved to the loading station to pick up a new crucible.

Abstract: A combustion tube comprises a generally cylindrical body with an outwardly extending annular tube stop spaced from one end of the combustion tube for engaging a combustion tube mounting assembly and fixing the tube in a precise position. Near the opposite end of the tube is an enlarged opening for receiving an upper seal assembly of a combustion furnace with the outer annular shoulder of the upper end of the tube having a rolled edge to facilitate the insertion of the tube through the seal in the upper seal assembly of the furnace. The combustion tube is made of quartz glass to withstand the temperatures encountered in the furnace. The combustion tube is specifically designed and adapted to be precisely positioned in an induction furnace with an easy tube removal system for the furnace.

Abstract: An electrode for a resistance analytical furnace has a crucible-engaging surface and an end spaced from the crucible-engaging surface having a plurality of grooves formed therein. A manifold mounted on the end of the electrode defines a dust recovery plenum and includes an outlet communicating with the plenum for coupling to a vacuum source to remove debris from the electrode. The improved electrode and electrode cleaning manifold positioned on the electrode provides a turbulent airflow for removal of dust and debris from an analytical furnace.

Abstract: An improved sample handling carousel is mounted to an analytical furnace at an acute angle and includes sample holding cavities which are readily visible at eye level to an operator. The rotary carousel can be easily removed from a stepwise driven drive shaft for filling the carousel at a remote location, such as a weighing station, or can be filled directly while mounted on the drive shaft. A tray is positioned below the carousel and has a slot for dropping a sample when one of the sample holding cavities aligns with the slot in the tray. In a preferred embodiment of the invention, the carousel is made of aluminum or a transparent polymeric material, such as acrylic.

Abstract: An automatic cleaning assembly for an analytical furnace is detachable from the filter chamber above the combustion tube. The cleaning assembly includes a rotating brush which is lowered through the filter chamber and into the combustion tube while a vacuum is drawn through the lower seal of the combustion tube. This results in a higher vacuum pressure differential and improved flow rate for removing dust from the filter of the furnace and the combustion tube.

Abstract: A crucible handling shuttle includes a pair of opposed dual crucible-gripping arms mounted on a rotatable head. The shuttle is removably plugged into a sliding block of a carriage to move between a furnace and a crucible loading station. The carriage includes mechanical, electrical, and pneumatic plugs or sockets which couple to mating sockets or plugs of the shuttle. A linear actuator extends between the carriage and the furnace base to raise and lower the carriage and shuttle coupled thereto.

Abstract: A combustion tube mounting system releasably mounts a combustion tube to an aperture in the floor of a furnace housing. The combustion tube has a base assembly with a cam and can be manually or automatically unlocked by cam pins in the floor for selectively engaging the cam for lowering the combustion tube from the floor of the furnace. When a new combustion tube is placed on the lower seal assembly and raised, it automatically aligns and engages the upper furnace seal and engages cams on the floor of the furnace housing which lock the combustion tube in place as it is introduced into the furnace.

Abstract: A crucible handling shuttle includes a pair of opposed dual crucible-gripping arms mounted on a rotatable head and moves between an induction furnace pedestal and a crucible loading station, such that one pair of arms pick up a crucible loaded with a preweighed sample, the shuttle moves to the induction furnace, where the other pair of arms grip and remove a spent crucible. The shutter head then rotates to deposit the new sample-holding crucible onto the pedestal and subsequently moves out of the furnace area to a sample disposal chute positioned between the crucible loading station and the furnace, whereupon the spent crucible is dropped for disposal. The shuttle head is then rotated and moved to the loading station to pick up a new crucible.

Abstract: A crucible and sample handling system and method provides a crucible-holding cartridge which is prepackaged to hold a plurality of crucibles. Upon removal of an end cap exposing an exit aperture, it is loaded onto a crucible delivery assembly which discharges individual crucibles from the cartridge onto a platform where a pick-and-place arm assembly places the crucible in a combustion furnace. Individual samples are dropped from stacked sample holding carousels onto a balance and, after weighing, are pneumatically drawn from the balance and introduced into the furnace and crucible for combustion.

Abstract: A crucible and sample handling system and method provides a crucible-holding cartridge which is prepackaged to hold a plurality of crucibles. Upon removal of an end cap exposing an exit aperture, it is loaded onto a crucible delivery assembly which discharges individual crucibles from the cartridge onto a platform where a pick-and-place arm assembly places the crucible in a combustion furnace. Individual samples are dropped from stacked sample holding carousels onto a balance and, after weighing, are pneumatically drawn from the balance and introduced into the furnace and crucible for combustion.

Abstract: A sample introduction system includes a drop chamber which can be sealed and outgassed and which includes a movable jaw selectively holding the sample in position above a conduit communicating with an open crucible for receiving a sample once the jaw has been moved to an open position releasing the sample. The jaw is actuated by a magnetic field which moves the jaw in an entirely enclosed system, thereby preventing the introduction of atmospheric contaminants during the operation of the sample dropping jaw from a closed, sample holding position to an open sample releasing position. By providing a magnetic actuator, such as a solenoid, for operation of the jaw, the sample chamber remains sealed during the sample dropping operation preventing contaminants from interfering with the analytical results.

Abstract: An assembly for extracting analytes from a sample using a fluid under pressure, and embodying the invention, includes an extraction cell receiving the sample and having a chamber body closed at one end by a translatable slide block assembly in fluid communication with the fluid under pressure to introduce the fluid under pressure into the sample located within the chamber body; and a cylinder block assembly at the opposite end of the chamber body for extracting the fluid passing through the sample, the sample being enclosed in a vessel having a thimble body closed at opposite ends by pressure-fit end cap assemblies, each having a thimble cap, a seal, and a frit cap assembly for retaining the sample within the thimble body and permitting the passage of the fluid therethrough.

Abstract: A calorimeter for determining the calorific value of a sample on the basis of the difference in temperature, measured on a real time basis, between the temperature of the water in a bucket containing the sample in a conventional calorimeter bomb and the temperature of the water in a reservoir maintained at substantially ambient temperature. The water from the reservoir is circulated by a pump through a heat exchanger, a water jacket surrounding the bucket and back to the reservoir in an effort to maintain the water in the system at ambient temperature. A method for calculating the corrected bucket temperature rise on the basis of Newton's Law of Cooling and for calculating the gross calorific value of the sample is also disclosed.

Abstract: An electrical resistance heated oven is used to heat a crucible to melt a sample and to simultaneously heat a casting dish into which the molten sample can be poured. The oven is cooled with the crucible and casting dish within the oven in order to prepare a sample bead for analysis. In another embodiment of the invention the sample is again melted in a crucible and after melting the crucible is moved out of the oven and turned to pour the molten sample into an acid solution positioned external to the oven. The crucible and sample can be moved while in the oven to mix the sample. The method of preparing an analytical sample using the electrical resistance heated oven is also disclosed.

Abstract: An interchangeable module for supporting a receptacle into which a molten sample, prepared by a fluxer, can be poured for analysis. One module can support a resistively heated casting dish into which a molten sample can be poured and cooled to form a solid sample for instrumental analysis. This module includes an insulator having a depression for receipt of a casting dish. A heating coil is positioned below the recession. A cooling gas conduit extends through the insulator support. The insulator is supported on a frame. The frame is supported on a back plate.