Abstract: A valve for regulating the flow of a liquid, for example in liquid chromatography, comprises a valve seat and a valve ball which are made of electrically conductive ceramic or glass material. Due to the electric conductivity, electrostatic charging is avoided which would otherwise attract dirt particles and lead to contamination and leakage of the valve. The valve is chemically inert and is not corroded by the solvents typically used in analytical chemistry.

Abstract: A piston pump shaft sealing system is provided which prevents particles released from the shaft seal, as a result of wear from entering and contaminating the fluid being pumped. The system features a permeable, deformable disc disposed between the seal and the displacement chamber of the pump. The piston shaft extends through a centrally exposed hole in the disc. In its undeformed state, the hole in the disc is smaller than the diameter of the piston shaft so that when the shaft is forced through the hole, the edges of the hole are pressed against the surface of the shaft, thereby scraping off seal particles deposited on the shaft. Forcing the shaft through the hole also deforms the disk into a conical shape, thereby forming an annular cavity between the disc and the seal which surrounds the piston shaft. The cavity serves to capture and retain the sealed particles, thereby preventing them from entering the fluid.