Abstract: A vacuum exhaust system can improve the operating efficiency of the vacuum exhaust system while reducing the system cost, to quickly attain a vacuum in the auxiliary chambers without increasing the size of the vacuum pumps. The vacuum exhaust system comprises a first pumping section and a second pumping section disposed downstream of and in series with the first pumping section. A main exhaust passage is provided to communicate a main chamber with a suction port of the first pumping section, and an auxiliary exhaust passage is provided to communicate an auxiliary chamber with a suction port of the second pumping section.

Abstract: The present invention thus provides a process for producing (D) a chlorinated hydrocarbon compound of the general formula (2): CnR1mHk(CR2R3Cl)j  (2) [wherein n is an integer of 1 to 12, m and k each independently is an integer of 0 to 25, j is an integer of 1 to 10; R1 represents an atom selected from the group consisting of chlorine, bromine, iodine, oxygen, nitrogen, sulfur and phosphorus and, when m is 2 or more, the two or more R1 groups may be the same or different, the group CnR1mHk having a valence of j does not contain any tertiary carbon-hydrogen bond; and R2 and R3 each independently represents a saturated aliphatic hydrocarbon group containing 1 to 5 carbon atoms or a group derived therefrom by substitution of a halogen atom or atoms for some hydrogen atom or atoms thereof and not containing a tertiary carbon-hydrogen bond],which process comprises adding (C) a protic acid to a mixture of (A) a compound of the general formula: CnR1mHk(CHR2R3)j  (1) [wherein m

Abstract: The transverse tooth profile of a screw rotor which meshes with a companion screw rotor is defined by a tooth root circular arc, an outer circumferential circular arc, and two curves interconnecting the tooth root circular arc and the outer circumferential circular arc. One of the curves is defined by a trochoid curve generated by a point on an outer circumferential surface of the companion screw rotor. Alternatively, the curve may comprise two curve segments, and one of the two curve segments comprising a tooth tip arc which is defined as an arc having a radius of curvature equal to or smaller than the difference between a radius of curvature of the outer circumferential circular arc and a radius of a pitch circle of the tooth profile, and the other of the two curve segments comprising a curve connected to the tooth root circular arc and determined by a curve generated by the tooth tip arc of the companion screw rotor.

Abstract: The transverse tooth profile of a screw rotor which meshes with a companion screw rotor is defined by a tooth root circular arc, an outer circumferential circular arc, and two curves interconnecting the tooth root circular arc and the outer circumferential circular arc. One of the curves is defined by a trochoid curve generated by a point on an outer circumferential surface of the companion screw rotor. Alternatively, the curve may comprise two curve segments, and one of the two curve segments comprising a tooth tip arc which is defined as an arc having a radius of curvature equal to or smaller than the difference between a radius of curvature of the outer circumferential circular arc and a radius of a pitch circle of the tooth profile, and the other of the two curve segments comprising a curve connected to the tooth root circular arc and determined by a curve generated by the tooth tip arc of the companion screw rotor.

Abstract: An engine control apparatus for changing the air/fuel ratio of an air-fuel mixture supplied to the engine to a richer value each time the exhaust gas temperature exceeds a target value while the engine is operating at high-speed and high-load conditions. During the air/fuel ratio control, the timing of the sparks supplied to the engine is changed, in relation to the changed air/fuel ratio, to retain the engine output torque at a uniform value.

Abstract: A lightning surge protector, comprises a current limiting element in a pressure-proof housing. The pressure-proof housing is composed of a conductive material and coupled with an upper electrode member. Also, a self arc-extinguishing LSP comprises a current limiting element and upper and lower electrode members housed and fixed in a conductive pressure-proof housing opened at its lower portion through a suspension structure composed of a suspension rod. The outside and inside of the housing are covered and filled with an insulator, so that, upon occurrence of an internal arc due to a short-circuit fault or the like, the energy due to the arc causes the lower electrode member to break the insulator in the vicinity of an opening portion of the conductive pressure-proof housing so as to electrically connect the conductive pressure-proof housing to a part of the lower electrode member.

Abstract: A method for detecting the presence or absence of an abnormality in a signal x having a frequency f from a signal source, is implemented by a circuit arrangement for deriving a now signal provided at the present time by the signal source, and for deriving a past signal at a point of time preceding the present time by an interval of time M/f where M is an integer. The circuit arrangement also detects an abnormality in the signal and/or the signal source compared to the new signal and to the past signal. The now signal x.sub.m is provided by the signal source at a point of. Another now-signal x.sup.'.sub.m is provided at a point of time preceding the now time t1 by t-1/4f. The signals Xm and xm are derived as a pair. A past signal x.sub.n corresponding to the signal x.sub.m and another past signal x'.sub.n corresponding to the signal x'.sub.m are also provided as a pair.

Abstract: A plurality of current detectors are provided in a plurality of prescribed spots of a transmission line for locating a fault caused, e.g. by lightning. A plurality of discriminators are provided in correspondence to the plurality of current detectors. Each discriminator receives detected signals from an arbitrary pair of the plurality of current detectors for detecting a relative difference between arrival times of the detected signals while extracting low-frequency components from the detected signals respectively and for detecting a phase difference between the extracted low-frequency components. A locator receives relative time difference data and phase difference data from the plurality of discriminators, to locate a faulty point in the transmission line on the basis of the received data.

Abstract: A plurality of current detectors are provided in a plurality of prescribed spots of a transmission line for locating a fault caused, e.g. by lightning. A plurality of discriminators are provided in correspondence to the plurality of current detectors. Each discriminator receives detected signals from an arbitrary pair of the plurality of current detectors for detecting a relative difference between arrival times of the detected signals while extracting low-frequency components from the detected signals respectively and for detecting a phase difference between the extracted low-frequency components. A locator receives relative time difference data and phase difference data from the plurality of discriminators, to locate a faulty point in the transmission line on the basis of the received data.