Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/02—Lubrication; Lubricant separation
  • F04C29/026—Lubricant separation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/04—Heating; Cooling; Heat insulation

Definitions

• the present invention concerns a screw compressor unit with an oil separator and a heat exchanger incorporated in one and the same body.
• Description of the prior art In the screw compressors known to prior art the functions of separating the lubricating oil from the compressed gas and cooling the oil by means of a heat exchange process are normally performed by physically distinct devices that are connected with each other by external piping to form a unit . This situation results in a substantial encumbrance and weights and requires for an interconnecting pipe system to link the various components, so that the joints implied by said system can also generate problems of losses of oil and/or gas.
• the heat exchanger means for cooling the oil are located within a shell delimiting the chamber for separating the oil from the compressed gas and then for collecting the separated oil. More particularly, the heat exchanger means comprise a heat exchange surface defined by a plurality of axial channels provided on said shell and in series communication with each other, a forced circulation of cooling air flowing over said heat exchange surface
• the shell housing the gas-oil separation unit is connected to the body of the compressor by coupling means consisting of a connection body and contains also filtering means, more particularly a coalescence-type de-oiling cartridge, to remove any residual trace of oil from the compressed gas.
• filtering means more particularly a coalescence-type de-oiling cartridge
• said coalescence-type de-oiling cartridge is mounted on the outside of the connection body and can therefore be easily removed and replaced without there being any need for dismantling the external cover and the gas-oil separation unit.
• the communication passages between adjacent pairs of the axial channels for cooling the oil are provided at the end of the shell, that is to say, on the connection body and the external cover or, alternately, formed directly within the ends of the shell.
• the forced air circulation is generated by means of a cooling fan operated either directly by the compressor motor or, preferably, provided with an autonomous motor and controlled by an oil temperature sensor, said fan being situated downstream of the compressor body and the shell .
• FIG. 2 shows another longitudinal section through the screw compressor unit in accordance with the invention shown in Figure 1 taken along line II -II;
• FIG. 3 illustrates three cross sections of the screw compressor unit in accordance with the invention taken along lines III-III, IV-IV and V-V of Figure 1 ;
• - Figure 6 shows a longitudinal section through another embodiment of the screw compressor unit in accordance with the invention;
• the reference number 1 indicates a motor, an electric motor for example, connected to a compressor body 2 delimiting a compression chamber 2a within which there are arranged two screw rotors 3 that suck the gas to be compressed, for example air from the environment, through a valve 8 and a filter 9 and then compress it by virtue of their rotation, discharging the compressed gas entraining lubricating oil into an outlet chamber 10.
• a motor an electric motor for example, connected to a compressor body 2 delimiting a compression chamber 2a within which there are arranged two screw rotors 3 that suck the gas to be compressed, for example air from the environment, through a valve 8 and a filter 9 and then compress it by virtue of their rotation, discharging the compressed gas entraining lubricating oil into an outlet chamber 10.
• compressor body 2 On the side opposite to motor 1, compressor body 2 is fixed to a first face of a connection body 4 that is provided with a passage 4a to allow outlet chamber 10 of compressor body 2 to communicate with a duct 11 arranged in the axial direction along a cylindrical shell 5 delimiting a separation chamber 14 and at its free end is closed by an external cover 6.
• Said duct 11 communicates with a duct 12 that extends diametrically within external cover 6, from which, in its turn, there extends in an axial direction, but in an eccentric position, yet another duct 12a that leads into a substantially bell-shaped separator element 13a arranged axially and in an eccentric position inside cylindrical shell 5 and within separation chamber 14. Given ' the speed at.
• the oil collected in chamber 14 flows through a duct 20, which can be seen only in Figure 5, to a series of longitudinal channels 21 provided on the wall of shell 5 that communicate with each other in series through U- shaped junction ducts 22 situated in connection body 4 and external cover 6. As it passes through said ducts, the oil exchanges heat with an air stream forced to circulate in contact with the outer surface of shell 5 where channels 21 are provided.
• the air stream is generated by a fan 23, which is arranged coaxially with and operated by motor 1 inside a tubular body 26 that is coaxial with the compressor and contains also motor 1, compressor body 2 and cylindrical shell 5.
• a thermostatic valve 25 assures a direct connection between chamber' 14 and filter 24, which enables the oil to avoid the run through channels 21 and thus accelerates its warm-up process.
• the entire unit is mounted on a support 7 like the one illustrated in Figure 1.
• FIGS 6 to 9 illustrate a second embodiment of the screw compressor in accordance with the invention and use the same reference numbers to indicate compressor components that are present also in the embodiment illustrated by Figures 1 to 5.
• the side of compressor body 2 opposite to motor 1 is attached to a first face of connection body 4 in which there is provided passage 4a that enables outlet chamber 10 to communicate with a duct 11 of a gas-oil separator unit generically indicated by the reference number 13.
• Said separation unit 13 is arranged within the cylindrical shell 5 that is attached to a second face of connection body 4 located on the opposite side of compressor body 2 and substantially parallel to the first face.
• Gas-oil separator unit 13 comprises duct 11 that extends within separation chamber 14 delimited by cylindrical shell 5 and leads into substantially bell- shaped separator element 13a located in the upper part of separation chamber 14 and aligned in parallel with the axis of shell 5.
• the inlet of outlet duct 15 for the de- oiled gas is placed in the upper part of separation chamber 14 and is in communication with a coalescence-type de-oiling cartridge 17, mounted on a side face of connection body 4, by means of a passage 4b provided in said connection body.
• a plurality of longitudinal channels is provided within cylindrical shell 5, of which the outer surface 5a is uniformly covered with radial fins to assure an efficient heat exchange.
• the channel 21 situated at the lowest level in separation chamber 14 has an opening 21a that serves as inlet for the separated oil, which will thus circulate in channels 21 by passing through the communication passages 22 between pairs of adjacent channels provided at the ends of shell 5, one of which can be seen in Figure 8.
• the coalescence-type de-oiling cartridge 17 is mounted on a nipple 17a projecting from the side wall of body 4 and communicates with a passage 18 within connection body 4 that makes the compressed gas available for use through a minimum pressure valve 19 and an outlet duct 27.
• a filter provided on the bottom of compressor body 2 assures the final conditioning of the cooled oil before it is re-circulated.
• Motor 1, compressor body 2, connection body 4 and cylindrical shell 5 delimiting separation chamber 14 are all arranged within a tubular body 26.
• Said tubular body has an enlarged end 26a on the side opposite to motor 1 that houses a fan 23 equipped with an autonomous motor 23a and serving to suck fresh air into tubular body 26 to cool the oil circulating in channels 21 through the finned heat exchange surface 5a provided on cylindrical shell 5.
• the gas compressed by screw rotors 3 is mixed with oil when it is discharged into outlet chamber 10, whence it reaches duct 11 through the passage 4a provided in connection body 4.
• Fan 23 is controlled by a thermostat, not shown on the drawings, as a function of the temperature of the cooled oil, so that it comes into operation only when this is necessary and will remain switched off, especially in the compressor start-up phase, until the oil reaches its steady state operating temperature .
• the entire unit is mounted on a support 7 like the one illustrated in Figure 6.
• the operation of replacing the de-oiling cartridge can be carried out with extreme simplicity, because it is installed outside cylindrical shell 5 and tubular body 26 and does not therefore requires dismantlement of oil separator unit 13. Furthermore, since this dismantling does not have to be catered for, the fan that circulates the oil cooling air can be arranged in a more rational position.
• the screw compressor could be supplied without motor 1, but provided with the mechanical connection means necessary for operating it, for example, a motor shaft capable of being connected to appropriate operating means at the user's disposal.
• a motor shaft capable of being connected to appropriate operating means at the user's disposal.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Applications Or Details Of Rotary Compressors (AREA)

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• 2002
  • 2002-04-16 WO PCT/IT2002/000239 patent/WO2002084124A1/en not_active Application Discontinuation
  • 2002-04-16 EP EP02728044A patent/EP1379786B1/de not_active Expired - Lifetime
  • 2002-04-16 AT AT02728044T patent/ATE291175T1/de not_active IP Right Cessation
  • 2002-04-16 DE DE60203272T patent/DE60203272T2/de not_active Expired - Lifetime
  • 2002-04-16 ES ES02728044T patent/ES2237678T3/es not_active Expired - Lifetime

Non-Patent Citations (1)

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