Abstract: A fitting body is tubular, whose first and second axial end portions include a connector for a tube and an annular groove, respectively. A sleeve has first and second axial end portions including an annular protrusion and a connector for another tube, respectively. A nut is engaged with an external thread of the fitting body or the sleeve. Engagement of the external thread with the nut causes press-fit of the annular protrusion into the annular groove to form a seal region. Under a condition that a depth of the annular groove is three or more times as large as a thickness of a radially inward or outward wall of the annular groove, an axial distance from the seal region to a bottom of the annular groove exceeds ten times an increment width of the annular groove caused by the press-fit of the annular protrusion into the annular groove.

Abstract: A fitting connects a first tube with a second tube. At least one of the tubes is twistable. The fitting includes a tubular body and a sleeve. A first axial end portion of the body includes a connector for the first tube. A second axial end portion of the body includes an annular groove and an internal thread. A first axial end portion of the sleeve includes an aunular protrusion to be press-fitted into the annular groove and an external thread to be engaged with the internal thread. A second axial end portion of the sleeve includes a connector for the second tube. A rotation angle between the internal and external threads necessary for connection therebetween is designed to fall within a range. At any angle within the range, the first tube connected with the body or the second tube connected with the sleeve can be twisted with one hand.

Abstract: A fitting body is tubular, whose first and second axial end portions include a connector for a tube and an annular groove, respectively. A sleeve has first and second axial end portions including an annular protrusion and a connector for another tube, respectively. A nut is engaged with an external thread of the fitting body or the sleeve. Engagement of the external thread with the nut causes press—fit of the annular protrusion into the annular groove to form a seal region. Under a condition that a depth of the annular groove is three or more times as large as a thickness of a radially inward or outward wall of the annular groove, an axial distance from the seal region to a bottom of the annular groove exceeds ten times an increment width of the annular groove caused by the press-fit of the annular protrusion into the annular groove.

Abstract: One of an external thread of a fitting body and an internal thread of a sleeve includes two thread ridges and the other includes two thread grooves. The two thread ridges have transverse cross sections different in shape or size. A transverse cross section of the first thread groove allows that of the first thread ridge to be fit thereinto. A transverse cross section of the second thread groove prevents that of the first thread ridge from being fit thereinto but allows that of the second thread ridge to be fit thereinto. A leading portion of the second thread ridge is tapered in width. A leading portion of the first thread groove is inversely tapered in width. A leading portion of the first thread ridge has a transverse cross section that extends beyond a transverse cross section of the leading portion of the second thread groove.

Abstract: A rolling diaphragm 5 of a rolling diaphragm pump 1 has a movable portion 31 reciprocatable together with a piston 3, a fixed portion 32 fixed to a housing 2, and a thin film portion 33 connecting the movable portion 31 and the fixed portion 32 and bending due to reciprocation of the piston 3. A rubber layer 6 is overlaid on the thin film portion 33 without being adhered to the thin film portion 33, an end portion 6a on the movable portion 31 side of the rubber layer 6 is fixed to the piston 3, and an end portion 6b on the fixed portion 32 side of the rubber layer 6 is fixed to the housing 2.

Abstract: A rolling diaphragm 5 of a rolling diaphragm pump 1 has a movable portion 31 reciprocatable together with a piston 3, a fixed portion 32 fixed to a housing 2, and a thin film portion 33 connecting the movable portion 31 and the fixed portion 32 and bending due to reciprocation of the piston 3. A rubber layer 6 is overlaid on the thin film portion 33 without being adhered to the thin film portion 33, an end portion 6a on the movable portion 31 side of the rubber layer 6 is fixed to the piston 3, and an end portion 6b on the fixed portion 32 side of the rubber layer 6 is fixed to the housing 2.