Sealing rotor, rotary pumps

A. Rotary Oil-Sealed Pump Designs. All of the commercial oil-sealed mechanical pumps are based on a rotor inside a cylindrical stator. These individ-... 

Another form of positive-acting rotary pump is the single-screw extruder pump typified by the Mono-piunp, illustrated in Figures 3.32 and 3.33. A specially shaped metal helical-rotor revolves eccentrically within a resilient rubber or plastic double-helix, thus creating a continuous forming cavity which progresses towards the discharge of the piunp. A continuous seal is created... 

The sequence of rotor assembly and balance correction shall follow ISO 5406. For balancing, the rotor does not include the pump half coupling hub or the rotary units of the mechanical seals. 

Figure 7.19. Some rotary positive displacement compressors, (a) A two-lobe blower, (b) Performance of a two-lobe blower (Rools-Connersville Co.), (c) A screw pump with one power and two idle rotors (Kristal and Annett, 1940). (d) Performance of 3.5" screw pump handling oils at 1150 rpm against 325 psig (Kristal and Annett, 1940). (e) Principle of the liquid ring seal compressor (Nash Engineering Co.). (0 A sliding vane blower (Beaeh-Russ Co.).

Fig. 29. A rotary-plate pump o—schematic view 6—-diagram of operation T—system being evacuated 2—eccentric rotor 5—stator 2—space where gas is compressed 5—movable plates d—discharge opening 7—discharge valve S—oil seal over valve...

The mechanical vacuum pump consists of an eccentrically mounted rotor driven inside a cylindrical housing. Two types of mechanical pumps are constructed (a) the rotary piston type, where the rotor comes in close contact with the housing and thus makes the seal between intake and exhaust compartments, and (b) the vane type pump where two vanes, spring-mounted in the rotor, make contact with the walls of the housing and thereby divide the space between the rotor and the housing. Typical construction is shown in Figs. 2 and 3. 

As an oil-sealed pump, the rotary piston pump uses a thin film of oil between the rotating piston and the pump casing (stator). When the rotor moves along the stator, the oil prevents the migration of gas from the compression stage to the low-pressure input. 

Rotary vane pump A displacement pump where the compression occurs in a non-symmetric chamber being swept by a rotor having an oil-sealed sliding vane. See also Vacuum pump. 

---