Abstract: A test apparatus for measuring the cohesive, adhesive and frictional properties of bulk solids has a bulk solid sample confined between two essentially parallel plates with a single load applied that produces both shear and normal stress and strain to the bulk solid in a manner that nearly uniformly distributes stress throughout the granular solid test region. The apparatus has a close proximity of the plates compared with the length of the plates in the direction of shear, the design of a load hanger to produce a resultant load near the shear plane, the roughening of any surface in contact with the solid that is not intended to have shear on it and involves one-directional movement of the parallel plates with respect to each other and the control of both the direction and magnitude of the applied load relative to the parallel plates.

Abstract: A test apparatus for measuring the cohesive, adhesive and frictional properties of bulk solids has a bulk solid sample confined between two essentially parallel plates with a single load applied that produces both shear and normal stress and strain to the bulk solid in a manner that nearly uniformly distributes stress throughout the granular solid test region. The apparatus has a close proximity of the plates compared with the length of the plates in the direction of shear, the design of a load hanger to produce a resultant load near the shear plane, the roughening of any surface in contact with the solid that is not intended to have shear on it and involves one-directional movement of the parallel plates with respect to each other and the control of both the direction and magnitude of the applied load relative to the parallel plates.

Abstract: Apparatus for blending particulate solids or liquids includes a blending vessel having a racetrack-shaped cross section at each elevation above its lower end. The racetrack-shaped cross section consists of two spaced opposed semicircles having ends that are joined by two spaced parallel line segments. Several embodiments of the apparatus are described; they all employ the racetrack-shaped blending vessel, which is highly effective in promoting mixing. In one embodiment the racetrack-shaped blending vessel is rotated about a horizontal axis so that the material passes through the vessel on each revolution. In another embodiment, a number of racetrack-shaped blending vessels are connected in a vertical sequence so that the material must pass through the blending vessels in succession.

Abstract: Apparatus for blending particulate solids or liquids includes a blending vessel having a racetrack-shaped cross section at each elevation above its lower end. The racetrack-shaped cross section consists of two spaced opposed semicircles having ends that are joined by two spaced parallel line segments. Several embodiments of the apparatus are described; they all employ the racetrack-shaped blending vessel, which is highly effective in promoting mixing. In one embodiment the racetrack-shaped blending vessel is rotated about a horizontal axis so that the material passes through the vessel on each revolution. In another embodiment, a number of racetrack-shaped blending vessels are connected in a vertical sequence so that the material must pass through the blending vessels in succession.

Abstract: A hopper that greatly reduces the tendency of the particulate material to form bridges within the hopper is shaped so that its walls slope downward more steeply at the bottom of the hopper and slope less steeply with increasing height above the outlet. In one embodiment the slope decreases continuously with increasing height above the outlet. In another embodiment the hopper is formed of successive sections, each joined around its circumference to the next-lower section, the wall of each section being less steeply inclined than the wall of the adjoining next-lower section. Exact relationships are given, relating the slopes of successive sections, and if the hopper is built in conformity with these relationships, arching of the particulate material is eliminated.

Abstract: Many types of processors of particulate materials operate more efficiently when they receive the particulate material in a steady stream. Most feeders tend to discharge in pulses. A hopper is interposed between the feeder and the processor. Surges in the feed rate are accumulated in the hopper, and lapses in the feed rate are compensated by the propensity of the hopper to discharge at a constant rate. Initiation of hopper flow is accomplished by use of a trap door. Mismatch between average feeder output rate and hopper discharge rate is corrected by use of an adaptive hopper having an outlet the size of which is slowly altered to maintain a constant amount of material in the hopper. A bypass hopper is used to control extremely variable input flow rates.

Abstract: An instrument for measuring certain physical properties of a sample of particulate material so that the flow characteristics of the material can be determined includes an improved compaction assembly having an upper piston that is surrounded by a retractable sleeve and further includes an improved test cell having cylindrical walls, having a failure outlet smaller than the diameter of the failure piston, and having a false bottom that can easily be removed from beneath a sample of compacted material to permit the failure portion of the test to be carried out. The tester can be used for determining the confined yield strength of the material, its bulk density, and its permeability.

Abstract: An improved flow-no-flow tester has two major advantages over its predecessor. First, it eliminates the need to invert the test cell after the compaction phase, thereby eliminating the possibility that failure of the compacted sample will occur before the failure load-measuring portion of the test can be done. Second, the improved tester determines the compaction load by measuring the force exerted by the sample against an upper piston, while a compressive force is applied to the sample by a lower piston. This results in greater accuracy than was obtained in the predecessor wherein the compaction load was taken to be the force applied to the compressing piston and which was in error due to the forces of friction and particle binding on the piston as it advanced against the sample. In addition, the improved tester minimizes the potential of particle binding during the failure portion of the test.

Abstract: Apparatus for densifying particulate solids and for removing air from the solids includes a screw feeder that conveys the material through a recirculation chamber, then into a high pressure shroud that is closed at its downstream end by a preloaded cover in yieldable sealing engagement with the downstream end of the high pressure shroud. In a preferred embodiment, the high pressure shroud includes a perforated section that extends upstream into the recirculation chamber so that as the particulate material is compressed by the screw in the high pressure shroud, air and some of the particles are expressed through the perforations and are contained by the recirculation chamber which directs the expressed particles downward into the screw which once again pushes them into the high pressure shroud.

Abstract: The discharge rate of a solid particulate material from a storage hopper is increased beyond the rate attainable by gravity flow along through the introduction of a pressurized gas into a plenum that lies over the discharge hopper. In one embodiment, a first pipe extends vertically downward from a storage hopper, and a second pipe of larger diameter is fitted over the lower end of the first pipe so that an annular plenum is formed between the pipes. A pressurized gas is injected into this plenum and results in an increase in the discharge rate. The discharge rate can be controlled by altering the pressure of the injected gas, and the flow can be rendered intermittent by opening and closing a gate valve at the outlet of the discharge hopper.

Abstract: A bin adapted for storing and dispensing particulate materials is formed by joining two or more bin modules of similar shape. The linear dimensions of the modules increase in a geometric series, with the smallest module being at the bottom. The modules are designed to prevent arching of the particular material to assure mass flow. Three embodiments of bin modules are described. In the first and the third embodiments, each module consists of two sections, but in a second embodiment the module consists of four sections. A bin constructed of these modules requires appreciably less head room than does a conical bin.

Abstract: A first body has a cylindrical section that is adjacent a conical section so as to form a constricted passage through which granular solids are forced under pressure. Passage through the constriction results in the application of shear forces to the granular solids which degrades some of the particles to create fines to fit between the larger particles and which induces interparticle motion that facilitates the compaction process. After passing through the constriction, the compacted solids are received in a cylindrical receiving chamber, into which a piston can be inserted for the application of direct compression forces. In a preferred embodiment, the granular solids are forced through several constricted passages in sucession, resulting in several stages of compaction prior to the final stage of direct compression.

Abstract: Apparatus and a test method for bench scale determination of whether a particulate material will flow under the action of gravity alone from an outlet in the bottom of a container. The apparatus includes a test cell having inclined conical side walls, and that is closed at its larger end by a plug having an inwardly-facing surface that is concave and conforms to a coaxial cone. In this way, cylindrical surfaces are avoided, and the shape of the space within the test cell offers minimal interference with the plastic stress field of the material. This testing method includes the novel step of inverting the test cell after consolidation of the test material but prior to application of the failure load.