A hydrostatic positive displacement machine has a cam ring for adjusting the displacement volume thereof. This cam ring is guided in translation by approximately diametrically arranged outer circumferential surface segments on associated inner surface segments of a housing of the positive displacement machine.

A three stage vacuum pump has three stages of fixed scrolls and orbiting scrolls that operate simultaneously. A motor drives the second orbiting scroll within the third fixed scroll upon three equally spaced idlers. One idler then transmits rotation and torque into the second stage. The second orbiting scroll has involutes upon both surfaces to engage the second fixed scroll inwardly and the first fixed scroll outwardly. The first fixed scroll has fins upon its back that extend into the atmosphere to transfer heat to air cool the pump. This pump also has a fan accelerating heat transfer. The pump operates the scrolls directly from a motor or from a motor and magnetic coupling so that the atmosphere does not infiltrate the pump.

A rotary vane pump or rotary vane motor including a rotatable rotor being eccentrically arranged within a rotatable cylindrical housing sleeve defining a freely rotary working chamber which takes out the relative sliding movement and friction inside to outer housing bearing. A partition element of a vane hingedly attached to the rotor; wherein the partition element travels with the rotor following the orbit of the housing incident to the expansion and contraction of the working space performing as a true dynamic radial seal; The rotor assembly along with the housing assembly being sandwiched between end-plates to fulfill dynamic side seal; The end-plates may contain pressure and non-pressure ports as well as holes for shaft, bearings, brackets and mounting hardware.