FI60761C - ANORDNING FOER DRAENERING AV OEVERSKOTTOLJA FRAON VAEXELLAODAN VID EN ROTORKOMPRESSOR - Google Patents

Description

-1 ΓβΙ ANNOUNCEMENT f Π 7 f A

IBJ O1) UTL AGC NI NGSSKKI FT eU'C 'i C Patent granted 10 03 1982' 5'Patent oeddelat v— ^ (51) Ky.lk.3 / lnt.CI.3 FC 29/02 ENGLISH I - Fl N LAN D (21) Ptt «nttlhak« mu * —Patwion «akn (n (751828 (22) Htkamispllvt - Ameknlngtdig l8.06-75 (23) AlkupUvt — Giltlghctadag 18.06.75 (41) Tullut | ulklMkal - Blhrtt offcntllf 25.12. 75

National Board of Patents and Registration (44) Nlht, vltolpenenkiniL] ulkaiwn ^ _

Patent- och registerstyrelsen '' Antökan uthgd och uti.skrift «n pubik * rad 30.11.81

(32) (33) (31) Pnrt «* qr« uo4k «is —Bugird prioriut 2k. 06.7U

Sweden-Sweden (SE) 7 ^ 08228-0 (71) Atlas Copco Aktiebolag, Nacka, Sweden-Sweden (SE) (72) Sven Evald Eriksson, Edegem, Belgium-Belgium (BE) (7 * 0 Berggren Oy Ab (5I4 The present invention relates to an apparatus for draining excess oil from the gearbox of an oil injection rotary compressor, in particular a screw compressor.

Known screw compressors (see Rotair Compressor, Service Manual, Holman Brothers Ltd, November 1960) have used a pump to drain excess oil from the gearbox. It is structurally necessary. Incidentally, in known oil injection rotary compressors, where it has not been possible due to the design to place the inlet at the lowest point of the machine, a pump has been used to drain excess oil from the gearbox, which has caused additional costs.

A rotor compressor is also known, which is a vane compressor, the working space of which is lubricated and cooled with oil (US-PS 2,305,317) and in which oil is pressed from the pressure-side oil separation and storage space under supply pressure through rotor pipes and bores to the gearbox.

2 60761

Mention should also be made of the known method of conducting oil into the working space of the vane compressor (CH-PS 173 842) via a riser extending through the oil separation and response space through which the condensed feed gas flows below the oil surface below the compressor. The adjustment of the gearbox oil level is not affected by this operation.

The object of the invention is, by means of a device as mentioned above and in a simple manner, to bring the lubrication of the compressor into contact with the oil storage in the gearbox, and at the same time to adjust the oil level of the gearbox without using an additional pump.

The object is solved by a device according to the invention, the characteristic features of which are given in the appended claims.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 is a longitudinal sectional view of a screw compressor, Figure 2 is a section along line 2-2 of Figure 1, Figure 3 is a longitudinal sectional view of another embodiment of a screw compressor and Figure 4 is a sectional view taken along line 4-4.

The screw compressor shown in Figures 1 and 2 comprises a housing 1 in which a main rotor 2 and a slide rotor (not shown) cooperating therewith are mounted on bearings 7, 8 and 9. When the compressor is operating, gas flows, compressing, from the inlet duct 4 to the outlet duct 5 and the air tank 24. 24 is provided with an air outlet nozzle 25. The lower part of the air tank acts as an oil tank. The pressure acting in the air tank forces the oil through the hole 27 in the air tank down to the line 26 and through the holes in the machine housing 1 to lubricate the rotors and cool the working fluid. To simplify the explanation, conventional oil separation devices and valves have been omitted. The main rotor 2 is provided with a shaft 6 on which a gear 11 60761 is mounted by means of a wedge 29, a plate 12 and a screw 13. The gear 11 cooperates with the gear 14. The gears are enclosed in a gearbox housing 10 fixed to the machine housing 1. The gear wheel 14 is provided with a shaft 15 to which a drive motor can be connected.

The housing 1 has a hole 17 through which some pressure generated by the compressor is conducted to the first line 16 and through a hole 18 in the gearbox housing 10 to pressurize the gearbox. The pressure in the gearbox forces the gears to lubricate the gearbox 11, 14 against the gravity of the injected oil down the second line 19, the opening 21 of which is close to the gearbox base 22, and through the hole 20 in the housing 1 to a compressor area lower than the hole 17.

In this way, the oil level in the gearbox 10 can always be kept constant in a simple manner, since the running compressor compresses the extra oil into the working space of the compressor, whereby the compression takes place only at the connection point 17 of the pressure line 16.

Figures 3 and 4 show another embodiment of the invention which differs from the embodiment shown in Figure 1 in that the pressure line 16 is replaced by a pressure channel 30 in the compressor workspace wall 23. The channel leads from its connection point 17 in the workspace wall to a bore 32 in the side wall 28 of the gearbox.

Similarly, in place of the oil line of Figure 1, an oil channel 31 in the wall 28 has been used in Figures 3 and 4, with the bore 20 in the wall 23 communicating with the channel 31. Thus a tighter structure achieves the same effect as lines 16 and 19 in Figures 1 and 2.

The embodiments of the invention described above and shown in the drawing are to be considered as examples only, which can be modified within the scope of the appended claims.