Abstract: A capillary pathway is dimensioned so that the driving force for the movement of liquid through the capillary pathway arises from capillary pressure. A plurality of groups of microstructures are fixed in the capillary pathway within discrete segments of the pathway for facilitating the transport of a liquid around curved portions of pathway. Capillary channels can be coupled between two adjacent groups of microstructures to either the inner and outer wall of the capillary pathway. The width of each capillary channel is generally smaller than the capillary pathway to which it is connected, and can be varied to achieve differences in fill initiation. The grouped microstructures are spaced from each other within each group on a nearest neighbor basis by less than that necessary to achieve capillary flow of liquid with each group. Each group of microstructures are spaced from any adjacent group by an inter-group space greater than the width of any adjacent capillary channels connected to the capillary pathway.

Abstract: A capillary hematocrit separation structure is included within a housing having a fluid inlet port, a reaction region, and a capillary pathway connecting the inlet port and the reaction region. The capillary pathway is dimensioned so that the driving force for the movement of liquid through the capillary pathway arises from capillary pressure. A plurality of obstructions are fixed in the capillary pathway, each obstruction having a concave portion facing toward the vented reaction region on the down stream side of the obstructions as viewed with reference to a liquid flowing from the inlet port to the reaction region. The capillary pathway in a hematocrit separation structure for a single drop sample size includes about 105 obstructions, each obstruction including a concave portion having a volume of between about 10−4 to 10−5 &mgr;l for selectively receiving hematocrit.

Abstract: A tube-and-shell heat exchanger system is disclosed which provides for partial heating of the cooler stream as it flows through a first compartment in the shell and conducting the partially heated stream to the outlet end of a second compartment in the shell to maintain the outlet end of the tubes at a higher temperature. The higher temperature at the outlet ends of the tubes avoids rapid fouling of tubes near the outflow end. There are provided slide bushings for tubes passing between the compartments in the shell. The slide bushings make possible heating of greater volumes of the cooler stream and maintaining the outlet end of tubes at higher temperature, while extracting more heat from the hot stream. The slide bushings provided may also be used to replace conventional expansion joints. The system is particularly useful in carbon black plants, where the hot smoke stream containing combustion gases and carbon black is used to preheat the air stream used for burning fuel in the reactor of the plant.