Shaft seals for a screw compressor
AssigneeSvenska Rotor Maskiner Aktiebolag
InventorLauritz Benedictus Schibbye
Life of this patent
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Abstract
Dynamic shaft seal system for a screw compressor with water injection comprising a water separator, where pressurized gas from the water separator is supplied around the rotor shafts as a blocking medium.
Claims19
In a screw compressor comprising a housing (10) defining a working space (18) containing a pair of intermeshing male and female screw rotors, the screw rotors being mounted in said housing (10) by means of respective rotor shaft means, said housing (10) further defining respective bearing chambers which are supplied with lubricant and into which said respective rotor shaft means extend;
- an inlet channel (20);
- an outlet channel (22);
- and port means in said housing communicating each of said inlet and outlet channels with the working space (18) of the housing, the improvement comprising:
- at least one shaft seal system associated with at least one of said rotor shaft means, each shaft seal system including:
- a pressure gas source means including at least a first pressure gas source (28), and means including port means in said working space for communicating said first pressure gas source with the high pressure side of the working space;
- and
- four spaced seal sections (58,56,54,52) mounted with a positive clearance relative to an associated rotor shaft means;
- an annular intermediate pressure chamber (64) being defined between the first (58) and second (56) seal sections, an annular blocking pressure chamber (62) being defined between the second (56) and third (54) seal sections and being in communication with said first pressure gas source (28), and a drain space (60) defined between the third (54) and the fourth (52) seal sections;
- said first seal section (58) being disposed between the working space (18) of the compressor and the intermediate pressure chamber (64), the second seal section (56) being disposed between the intermediate pressure chamber (64) and the blocking pressure chamber (62), the third seal section (54) being disposed between the blocking pressure chamber (62) and the drainage space (60), and the fourth seal section (52) being disposed between the drainage space (60) and the bearing chamber (36,40) of the related shaft means;
- and
- means for communicating said first pressure gas source (28) with said blocking chamber (62);
- said drain space draining away any lubricant from the bearing chamber passing over the fourth seal section and any gas passing over the third seal section.
In a screw compressor comprising a housing (10) defining a working space (18) containing a pair of intermeshing male and female screw rotors, the screw rotors being mounted in said housing (10) by means of respective rotor shaft means;
- an inlet channel (20);
- an outlet channel (22);
- and port means in said housing communicating each of said inlet and outlet channels with the working space (18) of the housing,
- the improvement comprising:
- at least one shaft seal system associated with at least one of said rotor shaft means, each shaft seal system including:
- a pressure gas source means including at least a first pressure gas source (28);
- and
- at least three spaced seal sections (58,56,54) mounted with a positive clearance relative to an associated rotor shaft means;
- an annular intermediate pressure chamber (64) being defined between the first (58) and second (56) seal sections, an annular blocking pressure chamber (62) being defined between the second (56) and third (54) seal sections and being in communication with said first pressure gas source (28), and a drain space (60) defined at least in part by the third seal section (54);
- said first seal section (58) being disposed between the working space (18) of the compressor and the intermediate pressure chamber (64), the second seal section (56) being disposed between the intermediate pressure chamber (64) and the blocking pressure chamber (62), and the third seal section (54) being disposed between the blocking pressure chamber (62) and the drainage space (60);
- port means in said compressor communicating said pressure gas source (28) with a blocking pressure chamber and with the high pressure side of the compressor;
- a capacity controlling valve provided in the inlet channel of the compressor;
- channel means communicating the intermediate pressure chamber with the inlet channel ahead of the capacity controlling valve;
- and
- means for allowing gas flow only in the direction from the inlet channel to said intermediate pressure chamber;
- said pressure gas source means further including means for pressure reduction provided between said first pressure gas source (28) and the blocking chamber (62).
Dependencies are inferred from the claim text.