Abstract: The disclosure relates to a pneumatic pressure regulator for pressure adjustment of a regulating pressure in a pressure chamber with a regulator membrane which is held in force equilibrium by a regulator spring and the regulating pressure, wherein the regulator membrane is coupled with a control valve in such a way that the control valve opens or closes in dependence upon the actual regulating pressure. For increasing the stability and the constancy of the regulating pressure it is proposed to form the control valve by a dimensionally stable ball which is seated in a loaded manner by means of a spring in a conical bore which tapers in the direction of the regulator membrane and is in a housing wall which lies opposite the regulator membrane with regard to the pressure chamber, the regulator membrane having a reinforcement in the contact region with the ball, and the ball following the movement of the regulator membrane in its normal direction.

Abstract: A method for operating an actuating drive for controlling fittings. The actuating drive has an electric motor which is fed from a frequency converter and moves a fitting with a predetermined torque via a self-locking gearbox. In order to protect the actuating drive against unacceptable, destructive heating while maintaining operation in the surrounding process installation when an excess temperature occurs, the temperature of the actuating drive is measured during continuous operation, and the rotation speed of the electric motor is reduced as a function of the measured temperature while maintaining the torque. To this end, the amplitude and the frequency of the output voltage of the frequency converter are reduced in proportion to one another.

Abstract: The invention relates to a switching device for the manual drive of an electromotive actuator for the control of fittings. In order to connect the manual drive by means of few components, whilst ensuring a simple design, the operative connection between the drive motor and the power take-off being maintained during manual drive, a drive shaft stub of the axially fixed drive shaft is equipped with a radial coupling pin. The handwheel shaft is mounted axially displaceably and in alignment with the drive shaft. That end of the handwheel shaft which is located opposite the handwheel is equipped with a coupling sleeve displaceable axially counter to the force of a compression spring. That end of the coupling sleeve which faces the drive shaft has a groove, the entrance of which is widened on both sides by means of run-on slopes.