Abstract: A device for feeding grease to the bearings of a rotary machine comprising a stator and a rotor, the device comprising injectors for injecting grease into said bearings, the injectors being controlled by an electronic control circuit which has inputs receiving signals from sensors for sensing parameters characteristic of the operating state of the bearings. The injectors are connected to a supply of grease under pressure and comprise injector blocks each connected to a respective bearing feeder channel. The sensors are pressure and temperature sensors, and the electronic circuit includes a clock and generates injection cycles as a function of a preestablished program, taking account of the information provided by the sensors and by the operating time of the bearings.

Abstract: A two stage dry primary pump comprises, in a single common stator: a screw pump at its low pressure end; and a fluid viscous effect, single rotary screw gas exhaust pump at its high pressure end; with a link duct providing communication between the screw pump and the viscous effect, single rotary screw gas exhaust pump. The invention is applicable to vacuum pumps.

Abstract: A pumping assembly for obtaining a high vacuum, the assembly comprising a primary pump (4) and a secondary pump (1) associated in series, the inlet of the secondary pump (1) being taken from an enclosure (3) to be evacuated, the assembly further including means (7) for starting the secondary pump (1) when the pressure upstream from the primary pump (4) drops below a value P.sub.1, the assembly being characterized in that a passive tank (10) followed by an isolating valve (11) are interposed between the outlet (12) from the secondary pump (1) and the inlet (13) to the primary pump (4), and in that it includes control means (7) for closing the isolating valve (11) and stopping the primary pump (4) when the pressure in said passive tank (10) reaches a value P.sub.2 <P.sub.1, and for opening the isolating valve (11) and restarting the primary pump (4) when the pressure in said passive tank ( 10) returns to the pressure P.sub.1.

Abstract: The machine comprises first and second screw rotors (1, 2) supported by bearings (47) in a stator casing (3) which is provided with a suction inlet and a delivery outlet, the first rotor is driven by a motor (10) and the second rotor is driven by means of synchronizing gearing (11-12) situated in a first chamber (14) of the casing and located between the motor (10) and one of the ends of the rotors, the gearing (11-12) running in a lubricating fluid (15), the machine is characterized in that the cavity (30) of the casing containing the rotors (1-2) is separated from the first chamber (14) by a first wall (16) having the shafts (8, 13) of the rotors passing therethrough via seals (17-18), in that the shafts of the rotors at the opposite ends of the rotors to the ends having the gearing pass through a second wall (20) via seals (24-25), and in that the casing (3 ) includes, beyond the second wall (20), a second chamber (31) connected to the first chamber (14) by a main pipe (29) provided with pumping means (49)

Abstract: A molecular or turbomolecular type of pump comprising a stator (2) and a rotor (3) rotated by a motor (7), the stator having a first zone overlying the rotor and in which gas is admitted, and a second zone adjacent to the drive motor and cooled by a flow of fluid (8), the pump being characterized in that the first zone is provided with heater (12) for maintaining the temperature of the first zone above the condensation threshold of the gas being admitted, with the first and second zones being separated from each other by a thermal impedance element (13).

Abstract: A method of starting series-coupled vacuum pumps comprising a primary pump (A) and at least one secondary pump (B) connected between the primary pump and an enclosure (E) in which a vacuum is to be established, the method consisting in starting the primary pump initially and subsequently starting the secondary pump when the suction pressure of the primary pump as reduced by rotation of the primary pump reaches an acceptable value, the method being characterized in that the pressure existing in the secondary pump is determined by using a physical magnitude related to the primary pump and following a law similar to the pressure law.

Abstract: The pump comprises a pump stator (5), an electric motor stator (4), and a rotor (6) that constitutes the rotor both of the pump and of the electric motor. The pump stator comprises a tubular non-magnetic lining to the electric motor stator, and the rotor is mounted excentrically inside said tubular lining and is equipped with radially movable vanes (63) that co-operate with said lining to provide pumping action when the rotor rotates. The arrangement is particularly applicable to oil-sealed vacuum pumps, and has the advantage of being more compact than units of similar performance, but equipped with a pump and a motor that are separate and interconnected by a mechanical coupling, as is conventional practice.

Abstract: Oxychlorination of ethylene with hydrochloric acid and oxygen with a fixed bed catalyst subdivided into independent reaction zones whereby a substantial proportion of the ethylene is converted to 1,1,2-trichloroethane and 1,1,2,2-tetrachloroethane along with 1,2-dichloroethane.