Abstract: A double-seat valve with an upper valve stem and a lower valve stem which, on the end, each have valve sealing bodies, each of which valve sealing bodies has a seal which is located on the balance diameter. One of the valve sealing bodies also has a center seal which is used to seal a leakage space when the valve stems are in the open position. The center seal also lies on the balance diameter. The other valve sealing body has a sealing collar, against which sealing collar the center seal is in contact when the valve stems are in the open position, so that even in this case, a sealing of the leakage space is guaranteed.

Abstract: The exact spring height as well as the spring pressure can be determined with a single arrangement for the optimal utilization of the axle loads of a multi-axle air spring suspended vehicle and to control the distance between the chassis and the axle. An air spring (2) is equipped with an ultrasonic pulse/echo measuring system. The air spring (2) includes a transmitter/receiver component (14) arranged on the chassis and a first reference electrode (20) and a reflector component (16) fixed to the axle. The air spring height can be determined in a conventional manner from the relative value of the running times of the ultrasonic pulses which are traversed on the reference path and the measuring path. A second reference reflector (22) is mounted at a different distance to the first reference reflector (20).

Abstract: The invention is directed to an arrangement for making contactless distance and pressure measurements within an air spring. With a single arrangement, the exact elevation of the spring as well as the spring pressure can be determined. This permits optimal utilization of the axle loads of a multi-axle vehicle and permits adjustment of the distance between the chassis and the axle. In the arrangement, an ultrasonic configuration makes contactless distance measurements in accordance with the pulse/echo method. The arrangement includes a transmitter/receiver component (4) mounted on the chassis and a first reflector (24) defining a first reference distance (16) therebetween. The component (4) and a reflector (6) define a measuring distance (30). The reflector (6) is fixedly mounted to the axle. The transmitter/receiver component (4) is elastically supported by a suspension (10) in a pipe stub (8) fixedly mounted to the chassis.

Abstract: The invention is directed to an arrangement for making contactless distance measurements within an air spring of a motor vehicle. With the invention, it is unnecessary to modify the longitudinal support of the motor vehicle for the purpose of integrating an ultrasonic distance measuring device. The arrangement includes a transmitter/receiver component (16) which is fixedly mounted to the chassis and is mounted within the air spring (2) laterally next to the support (10) of the vehicle, that is, the transmitter/receiver component is mounted elastically off-center in a tubular stub (14) arranged as part of the cover plate (4). A reflector component (24) is fixedly mounted on the axle and assigned to the transmitter/receiver component (16). The reflector component (24) is mounted on the roll-off piston (8) and includes a lens-shaped convex surface (26) having a surface normal (28) directed toward the transmitter/receiver component (16).

Abstract: For the preparation of polyethylenes using a diphenyl ethane derivative as C-C labile polymerization initiator, 1 to 40 mole 3,4-dimethyl-3,4-diphenyl hexane, based on 1 million mole ethylene used, are polymerized at 260.degree. to 400.degree. C. at a pressure of 60,000 to 350,000 kgfa.