Abstract: A compaction device for determining envelope and bulk densities of sample materials. The device uses a rotating sample cylinder and a plunger positioned within the cylinder. The force on the plunger is measured as the plunger advances in the cylinder. The position of the plunger at which a predetermined level of force is applied thereto is determined. Envelope density is determined from the difference in the advance of the plunger when the cylinder is partially filled with a dry flowing medium and when a sample material such as a rigid object is added into the medium. Bulk density is determined from the difference in the advance of the plunger when the cylinder is empty and when the cylinder contains a sample material such as a powder.

Abstract: An apparatus and method for measuring the volume and calculating the envelope density of an object of known weight. The apparatus has a hollow sample cylinder of known interior diameter mounted to a motor for rotation about its horizontal axis. A dry flowing medium is placed in the sample cylinder and a plunger is removably positioned therein. The plunger is mounted to another drive motor for axial movement within the sample cylinder to compact the dry flowing medium. A load cell connected to the plunger measures the force on the plunger as it advances in the sample cylinder. Control means responsive to the load cell determines the position of the plunger in the sample cylinder at which a known force is exerted on the plunger. The control means also calculates the volume of the dry flowing medium in the sample cylinder both with and without the object positioned therein and divides the difference in the volumes into the weight of the object.

Abstract: An apparatus and method are disclosed for obtaining adsorption data to be used for surface area and pore volume analysis. The apparatus and method utilize the differential pressures between a pair of dosing systems to indicate the amount of gas adsorbed by a sample. The system doses a sample chamber and a null chamber from essentially equal volumes of gas, and causes the chambers to be dosed such that any pressure difference between them, caused by adsorption, is eliminated. The resulting differential pressure between the essentially equal volumes of gas then indicates the amount of gas adsorbed by the sample. The system may be operated to dose in equilibrated increments or in a scanning mode in which adsorbate gas is continuously leaked into the sample chamber. A feedback circuit then controls dosing into the null chamber to eliminate the pressure difference caused by adsorption onto the sample surface.

Abstract: A gas comparison pycnometer is disclosed which provides a method and apparatus for determining and checking the accuracy of the volume of a solid substance. The pycnometer is also outfitted with a unique cap assembly which fixes the volume in the pycnometer's sample chamber from run to run. The pycnometer also employs a series of purges with a suitable gas to carry unwanted moisture and vapors out of the system. This pycnometer solves many problems in the prior art by quickly and accurately determining the volume of a solid substance.

Abstract: The invention provides improvements in a system for carrying out volumetric sorption analysis of porous materials. According to one aspect of the invention, the saturation pressure of the adsorbate gas is measured after dosing of the sample during an actual run has brought the adsorbate gas to a saturation condition above the sample, and this measured saturation pressure is then used by the system to determine the relative pressures at which data will be taken during desorption. In accordance with another aspect of the invention, the system automatically adds extra adsorbate gas to the dosing manifold until the analysis proceeds beyond a selected relative pressure, so that far fewer doses are required to reach initial target relative pressures in the case of materials which adsorb large amounts of gas at low relative pressures.

Abstract: An automated device for warming and cooling a sample is disclosed, and is particularly useful in connection with a flowing gas surface area analyzer. The device is capable of directing a flow of room temperature air onto a sample chamber after the chamber is removed from a coolant, thus rapidly warming the sample up to, but not exceeding, room temperature. In the disclosed embodiment, a Dewar flask containing coolant is mounted on an elevator platform. The flask is mechanically raised or lowered so as to immerse the sample chamber, located above the flask, in the coolant. A fan directs a flow of air onto the sample after the flask is lowered away from the sample chamber. A logic controller, connected to a timer, operates and regulates the cooling and warming process. The elevator assembly, fan and controller are disposed within a housing. The sample chamber is connected to gas input and output tubes, which are monitored by a detector for the composition of gas passing through the tubes.

Abstract: An apparatus for maintaining a constant temperature within a vessel immersed in a liquid by surrounding a portion of the vessel, extending above the surface of the liquid, with a wick. The wick conducts liquid up to a predetermined point on the vessel and maintains the liquid at that point, regardless of changes in the level of the liquid due to evaporation. The wick is encased within a layer of heat insulating or heat conducting material to further aid in maintaining a constant temperature within the vessel. A second embodiment, including alternating layers of heat conducting and heat insulating material, is disclosed for increased temperature control. The disclosed apparatus is particularly useful for maintaining a constant temperature within a vessel attached to a scientific instrument, such as a pore volume and surface area analyzer.

Abstract: Sample introduction apparatus useful in liquid chromatography and including a valve body having at least one fluid passage of precisely defined volume to receive a sample material and having another fluid passage delivering carrier liquid to a liquid chromatograph. The valve body can be manipulated to place the precisely defined volume in the chromatograph fluid circuit, so that the sample contained within the volume is positively displaced into the chromatograph.

Abstract: Apparatus used in the field of liquid chromatography. There is disclosed pump apparatus for continuously delivering a flow of carrier liquid either at a constant rate of flow or at a constant pressure. The pump apparatus includes a pair of differential-piston pressure intensifiers which are sequentially operated so that the high-pressure sides of the pressure intensifiers sequentially supply carrier liquid to the chromatograph column. Each pressure intensifier is sequentially operated by a constant-rate of flow application of hydraulic liquid, with essentially pulseless operating transition between pressure intensifiers occurring during constant-pressure application of hydraulic liquid to both of the pressure intensifiers at a pressure measured during previous constant-volume hydraulic operation. An embodiment of the pump apparatus pumps plural carrier liquids in desired fixed or variable proportions.

Abstract: An apparatus for maintaining a constant temperature within a vessel immersed in a liquid by surrounding a portion of the vessel, extending above the surface of the liquid, with a wick. The wick conducts liquid up to a predetermined point on the vessel and maintains the liquid at that point, regardless of changes in the level of the liquid due to evaporation. The wick is encased within a layer of heat insulating or heat conducting material to further aid in maintaining a constant temperature within the vessel. A second embodiment, including alternating layers of heat conducting and heat insulating material, is disclosed for increased temperature control. The disclosed apparatus is particularly useful for maintaining a constant temperature within a vessel attached to a scientific instrument, such as a port volume and surface area analyzer.