DE2619542A1 - Twin shaft helical gear rotary compressor - has annular grooves in cover and pockets in teeth to balance axial forces - Google Patents

Abstract

The rotary compressor has a housing in which a rotor (1) with helical teeth meshes with a rotor (2) with helical grooves, and is designed to balance the forces in axial direction due to the helical shape of the teeth. Pockets (4, 10) are provided in the end faces on the suction side to counteract these forces to the extent which is compatible with the effective life of the roller bearings on the suction side. The pockets connect with annular grooves (3, 11) which communicate with annular grooves (21, 6) on the pressure side via bores (5, 13). The balancing pressure thereby obtained lies between the outlet and inlet pressure and is determined either by the geometry of recesses (7, 14) in the end cover on the pressure side, or of the end face gaps and the profile of the pockets.

Description

Two-axis rotary lobe compressor with internal compensation of the side forces

The present invention deals with parallel and off-axis Rotary piston machine with meshing engagement between a helical rib rotor and a helical groove rotor, which has minimal side forces with the highest degree of efficiency. The balancing of the side forces is desirable because of the high speed and the Use of roller bearings in the main rotor is particularly important.

The previously known devices for balancing the axial forces use elaborate combinations of piston and cylinder or reduce the on The force acting on the pressure-side face of the rotor through relief spaces.

FIG. 1 shows parts of two rotors accommodated in a housing. Di e FIGS. 2 and 3 show the measures according to the invention for relieving lateral force on the end faces of the rotors 1, 2 and a roller bearing arrangement suitable for this.

Figures 2, 3 show the measure proposed here for the main rotor 1 of the screw compressor working with a high compression ratio, a sufficient and sufficiently adaptable side force relief via an annular channel 3 arranged on its suction side into which the flat relief pockets 4, which are effective within the front profile, open. This channel 3 with its pockets 4 is chsdru ck via one or more axially parallel rotor bores 5 with a Ausg lei in the area of + 50%, which can be set precisely and easily within the specified limits in a current pressure-side Kingkanai o by means of a correspondingly arranged pressure cover tray. This pressure P m prevailing in the annular channels 3 and 6 is sealed here in a known manner by means of threaded gap seals 8 and 9 against the suction pressure P prevailing in the storage rooms.

The side force problem is less powerful with m secondary rotor 2 of the screw compressor working with high Dichtungsverhäl tnis because of its smaller diameter, its lower speed and because of the narrow profiles and requires smaller relief pockets 10, which are also shown here in the manner shown for the main rotor l Ring channels 11 and 21 as well as rotor holes 13 and corresponding cover trays with an equalizing pressure are supplied. The value P can be different from P. However, for one or both runners it is also possible to dispense with the troughs 7 and 14 provided for P and P and to effect the self-adjustment of these equilibrium prints within the specified limits through the dimensions of the front gaps and pocket profiles.

The radial load on the pressure side is carried by roller bearings on both rotors recorded with high sustaining capacity. A remnant of unbalanced lateral forces from the in the sense of a good runner performance even when idling, is on the suction side added by precisely adjustable shoulder bearings 15, those on the pressure side appropriate Counter shoulder bearings 16 are assigned, which are loaded by springs 17. if the main rotor by a more slowly rotating drive machine via belts or a gear is driven, then the guide shoulder bearing 15 must have a roller bearing 18 upstream. Otherwise, the guide shoulder bearing can still use the take on the small radial load on the suction side.

The exact measurable readjustment of the Fürungslager 15 in the sense of a The end gap on the pressure side that is still permissible can be achieved by means of an adjusting ring 19.

All of these roller bearings have a high compression ratio screw compressor can with desirable dimensions for a service life of more than 50,000 Hours to be scheduled.

For the limit of applicability of roller bearings, one finds here, because of the side force relief that is always possible to a sufficient extent, a condition of a presumed service life which is only prescribed by the pressure-side roller bearing 20.

In contrast to the screw compressor working with a high pressure ratio, where the housing and rotor are injected by an amount that is more than that of the gas supply Circulating oil are cooled, the cooling is still sufficient here by heat conduction in the short and suitably ribbed housing and by gas heat conduction causes over the pressure-side face towards the well-cooled pressure cover, which can be sprayed through oil nozzles.

The front gaps on the pressure side of the two change here runners supporting fixed shoulder bearings in the sense of axially acting thermal stability, with a well-cooled pressure lid and a positive temperature gradient between acts on the rotors and the housing in the sense of the smallest possible front gap losses.

Claims (4)

Claims I.Pora 1 lel- and external axis Rotationsko Ibenmasch ne with meshing engagement between a helical rib rotor and a helical groove rotor. The two rotors are in a housing delimited by side parts arranged rotatably and have devices for internal compensation of the side forces characterized in that the axially directed lateral forces caused by the tooth shape both rotors 1, 2 in a leading one with the service life of the suction side Shoulder roller bearings 15 verftlicher size through pockets 4 and 10 within the suction side End faces are compensated. These pockets open into annular channels 3 and 11, the are connected via bores 5 and 13 with ring channels 21 and 6 on the pressure side and in this way loaded with an equalizing pressure (P. P) prevailing there will. The resulting equalization pressure lies between the outlet pressure (P) and the suction pressure (P) and is either arbitrarily arranged by appropriately Troughs (7 and 14) in the pressure cover or only depending on the front gaps of both Sides and the pocket profiles. 2. Parallel and external-axis rotary piston machine according to claim 1, characterized in that the suction-side leading and adjustable shoulder roller bearing a much smaller counter bearing supported by springs is assigned on the pressure side which is preceded by a roller bearing. 3. Parallel and external-axis rotary piston machine according to claim 1, characterized by an internally cooled main rotor and an indirectly via wide head area cooled by gas heat conduction. 4. Parallel and external-axis rotary piston machine according to claim 1 for dry running, characterized by longitudinally ribbed housing walls for cooling, the heat conduction via the pressure-side end gaps by gas heat conduction on the pressure cover, which is sprayed intensively with cooling oil.