US20080253914A1 - Liquid injection type screw compressor - Google Patents

Liquid injection type screw compressor Download PDF

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Publication number
US20080253914A1
US20080253914A1 US12/111,624 US11162408A US2008253914A1 US 20080253914 A1 US20080253914 A1 US 20080253914A1 US 11162408 A US11162408 A US 11162408A US 2008253914 A1 US2008253914 A1 US 2008253914A1
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United States
Prior art keywords
rotor
lip
bore
casing
gas inlet
Prior art date
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Abandoned
Application number
US12/111,624
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English (en)
Inventor
Yoshifusa KUBOTA
Yoshiyuki Kobayashi
Shigeru Muta
Yasuaki ENDO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mayekawa Manufacturing Co
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Mayekawa Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mayekawa Manufacturing Co filed Critical Mayekawa Manufacturing Co
Assigned to MAYEKAWA MFG. CO., LTD. reassignment MAYEKAWA MFG. CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ENDO, YASUAKI, KOBAYASHI, YOSHIYUKI, KUBOTA, YOSHIFUSA, MUTA, SHIGERU
Publication of US20080253914A1 publication Critical patent/US20080253914A1/en
Abandoned legal-status Critical Current

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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
    • F04C29/0007—Injection of a fluid in the working chamber for sealing, cooling and lubricating
    • 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
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • 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
    • F04C29/028—Means for improving or restricting lubricant flow
    • 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
    • F04C29/12—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • 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
    • F04C2240/00—Components
    • F04C2240/10—Stators

Definitions

  • the present invention relates to a liquid injection type screw compressor comprising a pair of male and female screw rotors that are installed in a space surrounded by a bore face within a casing of the compressor, while a liquid such as oil or water is injected to the bore face; whereby, a lip part is provided so as to prevent the liquid from flowing-back to a working gas inlet side, being placed on the bore face, within a range from a suction seal line (a suction closure line or a suction containment boundary locus) to a line parallel thereto apart from the suction seal line, by a distance equal to one screw pitch (a tooth groove distance in the rotor axis direction) of the rotors.
  • a suction seal line a suction closure line or a suction containment boundary locus
  • liquid injection type screw compressors In hitherto known liquid injection type screw compressors, a pair of a male screw rotor and a female screw rotor within a casing of the compressor are engaged in each other, so as to form a working/operation space inside which a liquid such as oil or water is injected whereby a working substance of a gas-liquid mixing phase is pressurized.
  • the liquid injection brings the screw compressor a cooling function, a sealing function, and a lubricating function; thus, the compressor of the type obtains high efficiency even during a low speed operation, becoming widespread in the industry.
  • the bore faces forming the working space within the casing of the compressor are important elements so as to secure gas/liquid tightness, when the working space is under a compression process where a gas seal across adjacent tooth spaces is required; consequently, it is a prerequisite to keep the clearance between the addendum circles of the rotors (tooth tip surfaces of the rotors) and the bore faces as small as possible.
  • the bore faces in the part as mentioned are called main bore faces.
  • a weir (a lip part) is provided therein so as to prevent oil from scattering through a suction side end face of the rotor casing toward a gas inlet side; thus, it is intended to preserve the compressor volumetric efficiency and reduce the compressor power loss.
  • FIGS. 1 and 2 in the patent literature 1 disclose that a lip (weir) 44 is provided between a gas inlet 24 and an expanded bore part 40 so as to lessen a heat exchange between a hot back-flow gas from a compression space formed in a rotor tooth space, and a flow-in gas from the gas inlet 24 .
  • FIG. 1 in the patent literature 2 discloses a lip (weir) 39 that is provided at a suction side end-face of a casing 3 so that the lip 39 prevents a back-flow oil from flowing from expanded bore parts 7 and 8 back to a gas inlet side, from warming-up an inhaled gas, and also from deteriorating a charging efficiency of the inhaled gas to be charged into a rotor teeth space.
  • the patent literature 3 discloses that the oil injected into a working space flows back to a gas inhaling space; thereby, an oil mist generated from the back-flow oil suspends in the gas inhaling space, while the oil mist heats up the inhaled gas under a suction process; namely, a phenomenon, what is called inhaled gas heating, occurs; thus, the phenomenon increases a temperature of the gas to be compressed as well as expands a volume thereof; as a result, in a displacement type compressor that needs to inhale a gas of a constant specific volume, not only a reduction of mass-throughput but also a deterioration of volumetric efficiency are brought.
  • a lip part 5 is provided at a suction side end-face of a casing 3 that accommodates the rotors, so that the lip part 5 protrudes inside, i.e. toward screw rotors; further, a heat-up prevention wall (a baffle plate) 8 to close a gap between the screw rotors and the lip part 5 is provided so as to prevent an inhaled gas from leaking toward a gas inlet side.
  • a heat-up prevention wall (a baffle plate) 8 to close a gap between the screw rotors and the lip part 5 is provided so as to prevent an inhaled gas from leaking toward a gas inlet side.
  • FIGS. 9 a and 9 b that are attached to this application shows a casing for conventional screw rotors; for explanatory convenience, FIG. 9 a shows a divided upper half and FIG. 9 b shows a divided lower half.
  • FIGS. 9 a and 9 b a space that accommodates a male rotor and a female rotor is formed inside the casing 01 ; thereby, the boundary of the space comprises:
  • a lip part 04 is provided along a suction side end-face of a casing 01 so that the lip part 04 of the casing 01 protrudes inside, toward screw rotors; on the other hand, a suction seal line (a suction containment boundary locus) 05 is formed on a boundary between the male rotor side main-bore-face 02 a and the male rotor side expanded-bore-face 03 a as well as between the female rotor side main-bore-face 02 b and the female rotor side expanded-bore-face 03 b.
  • a working space is formed with a tooth space of the male rotor and another working space is formed with a tooth space of the female rotor, the pair of tooth spaces being independent; whereby, the tooth spaces are engraved on an outer periphery of rotors along a screw tooth spiral.
  • the working spaces While the working spaces are communicated with the expanded-bore-faces 03 a or 03 b , the working spaces are gradually expanded to a maximum volume, inhaling a gas through a gas inlet; then, the working spaces pass through the suction seal line (the suction containment boundary locus) 05 , and the working spaces form a closed space the boundary of which includes a male rotor side main-bore-face 02 a and a female rotor side main-bore-face 02 b .
  • the suction seal line the suction containment boundary locus
  • a liquid such as oil or water is injected into the working space, for the purpose of cooling, sealing, and lubricating.
  • FIGS. 10 a and 10 b schematically depicts bore faces of a conventional screw rotor casing.
  • FIG. 10 a shows a transparently perspective view seen from the top, depicting a suction seal line and a lip part.
  • FIG. 10 b is a development of FIG. 10 a.
  • the reference numeral 01 a denotes a male rotor side casing
  • the numeral 01 b does a femamale rotor side casing 01 b
  • a suction seal line 05 is formed on a boundary between a male rotor side main-bore-face 02 a and the male rotor side expanded-bore-face 03 a as well as between the female rotor side main-bore-face 02 b and the female rotor side expanded-bore-face 03 b
  • a lip part 04 of the casing 01 protrudes inside, toward screw rotors.
  • the working (operation) spaces formed with the male rotor and the female rotor face the male rotor side expanded-bore-face 03 a and the female rotor side expanded-bore-face 03 b , while the working spaces gradually increase during a suction process, inhaling a gas through a gas inlet.
  • the spaces form a sealed space, being surrounded by the main-bore-faces 02 a and 02 b .
  • the compressed gas is discharged through a discharge opening at a discharge side end face 07 of the rotor casing.
  • the liquid such as oil or water injected into the working spaces leaks toward a lower pressure suction side and accumulates in the concaved expanded bore faces 03 a / 03 b .
  • the lip part 04 prevents the liquid from leaking and scattering toward the gas suction end face 06 of the rotor casing.
  • the lip part is provided at the suction side end face of the rotor casings in conventional liquid injection screw compressors; thus, a gas inlet has to be placed outside across the suction side end face; moreover, the lip part lessens a gas inlet passage area (opening area) around the suction side end face of the rotor casings; therefore, in case of manufacturing a mono-block casting of the rotor casings and the gas inlet casing, it becomes difficult to allocate a casting core for rotor casing bores.
  • the invention aims at realizing a liquid injection type screw compressor provided with a variable compression ratio mechanism, that is, an internal volume ratio adjusting valve; wherein, the compressor has a compact structure so as to not prolong a manipulation mechanism of the internal volume ratio adjusting valve, making manufacturing cost be further reduced.
  • liquid injection type screw compressor comprising of:
  • a lip part for preventing liquid from back-flowing toward a gas inlet is provided on a casing bores, within a range between a suction seal line and a line that is apart from the suction seal line, by one screw pitch distance of the screw rotors, toward the expanded-bore-face side of the male rotor side casing and/or the female rotor side casing; hence, the lip part is placed nearer to the suction seal line in comparison with conventional ways; as a result, a liquid leakage from the compressed working spaces toward the gas inlet side is effectively prevented; further, the lip part placed nearer to the suction seal line makes it possible to eliminate a part of bore faces that is located at the gas inlet side from the lip part. So can be realized a simplified configuration of rotor casings with a reduced bore surface as well as a reduced suction resistance and a reduced manufacturing cost which are attributable to the simplification.
  • a preferable configuration of the present invention may comprise:
  • the above preferable configuration can surely prevent a liquid leakage around a neighborhood along the bore intersection line.
  • the above configuration can surely prevent a liquid leakage around the bore intersection line.
  • Another preferable aspect of the invention according to the mentioned configuration is the liquid injection type screw compressor, wherein the rotor casing with the gas inlet casing is formed in one piece or a plurality of divided-pieces from the lip ending edge toward a gas downstream side.
  • the gas inlet side bore surface of the rotor casing can be omitted in a way that the lip part is located nearer to the suction seal line; as a result, it becomes possible to form a gas inlet casing and a rotor casing in one body.
  • the invention realizes a smaller rotor casing, saving an installation space; in addition, the invention greatly relieves restrictions concerning a position where a gas inlet casing is disposed in a rotor casing; in this regard, the degree of freedom as to the gas inlet casing design can be greatly expanded.
  • a labyrinth structure is embodied on the inner surface which faces rotor tooth tips in the lip part.
  • a pertinent roughness of the surface e. g. a pertinent casting surface roughness
  • an intended uneven surface can realize lesser liquid leakage.
  • different outer diameters are applied to a pair of the male rotor and the female rotor so that the outer diameter of the male rotor is greater than that of the female rotor, and the number of the male rotor teeth is fewer than that of the male rotor teeth in a case when the same outer diameter is applied to a pair of the male rotor and the female rotor.
  • the lip part is provided at the lower side of the casing bore surfaces.
  • the liquid accumulated by gravity at the bottom of the bore surfaces can be easily prevented from scattering toward the gas inlet side; thus, a simple structure can be realized.
  • liquid injection type screw compressor comprising:
  • the positioning means comprises:
  • a driving mechanism to position the internal volume ratio-adjusting valve can be formed as a compact one.
  • the mentioned connection part between the hollow shaft and the rotation rod may be a bevel gear pair or a crossed helical gear pair.
  • a lip part for preventing liquid from back-flowing toward a suction inlet is provided on a casing bores, within a range between a suction seal line and a line that is apart from the suction seal line, by one screw pitch distance of the screw rotors, toward the expanded-bore-face side of the male rotor side casing and/or the female rotor side casing.
  • the lip part placed nearer to the suction seal line makes it possible to eliminate a part of the rotor casing at the gas inlet side from the lip part. So can be realized a simplified configuration of rotor casings with a reduced bore surface as well as a reduced suction resistance of an inhaled gas and an enhanced volumetric efficiency of the compressor.
  • the lip part placed nearer to the suction seal line makes it possible to eliminate a part of the rotor bore faces at the gas inlet side from the lip part.
  • the rotor casing can be formed in one body with a gas inlet casing.
  • manufacturing processes can be simplified and a manufacturing cost can be reduced. Consequently, the disclosed invention greatly relieves restrictions regarding installation position of a gas inlet casing in a rotor casing.
  • the degree of freedom as to the gas inlet casing design can be greatly expanded; in addition, a compact casing can be realized and a compressor installation space can be reduced.
  • the compressor comprises:
  • the above configuration can surely prevent a liquid leakage around a neighborhood along the bore intersection line.
  • the compressor comprises:
  • the above configuration can surely prevent a liquid leakage around a neighborhood along the bore intersection line.
  • a screw compressor in a screw compressor according to the disclosed invention, different outer diameters are applied to a pair of the male rotor and the female rotor so that the outer diameter of the male rotor is greater than that of the female rotor, and the number of the male rotor teeth is fewer than that of the male rotor teeth in a case when the same outer diameter is applied to a pair of the male rotor and the female rotor.
  • the compressor comprises:
  • an internal volume ratio (U i ) adjusting valve can make a whole compressor compact, realizing a compressor of three kinds of compression ratios, namely, of lower/medium/higher compression ratios, without changing a gas inlet casing, only by replacing a rotor casing.
  • a gas inlet casing can be applied to these kinds of compressors in common.
  • the compressor comprises a positioning means for positioning the internal volume ratio-adjusting valve, the positioning means comprising:
  • a driving mechanism to position the internal volume ratio-adjusting valve can be formed as a compact one.
  • FIG. 1 a shows a transparently perspective view seen from a top as to a first embodiment of the present invention
  • FIG. 1 b is a development view of FIG. 1 a;
  • FIG. 2 a shows a perspective view of an upper side rotor-casing seen from the inside thereof, as to a first embodiment
  • FIG. 2 b shows a perspective view of a lower side rotor-casing seen from the inside thereof, as to the first embodiment
  • FIG. 3 shows a perspective view of apart of a rotor casing as to the first embodiment
  • FIG. 4 shows a longitudinal plan view of a second embodiment of the present invention
  • FIG. 5 shows a longitudinal section view concerning the second embodiment
  • FIG. 6 explains a development view showing a suction seal line (a suction containment boundary locus) as to each of the male/female rotors that have different tip diameters;
  • FIG. 7 gives an explanation about the male/female rotors that have different tip diameters
  • FIG. 8 shows a perspective view as to a variation of the second embodiment
  • FIG. 9 a shows a perspective view of an upper side rotor-casing seen from the inside thereof, as to a conventional compressor;
  • FIG. 9 b shows a perspective view of a lower side rotor-casing seen from the inside thereof, as to a conventional compressor;
  • FIG. 10 a shows a transparently perspective view seen from the top as to a conventional compressor in consideration of a schematic explanation for bore faces thereof;
  • FIG. 10 b is a development view of FIG. 10 a.
  • FIG. 1 a shows a transparently perspective view seen from the top as to a first embodiment of the present invention
  • FIG. 1 b is a development view of FIG. 1 a
  • FIG. 2 a shows a perspective view of an upper side rotor-casing seen from the inside thereof, as to the first embodiment
  • FIG. 2 b shows a perspective view of a lower side rotor-casing seen from the inside thereof, as to the first embodiment
  • FIG. 3 shows a perspective view of a part of a rotor casing as to the first embodiment
  • FIG. 4 shows a longitudinal plan view of a second embodiment of the present invention
  • FIG. 5 shows a longitudinal section view concerning the second embodiment
  • FIG. 6 explains a suction seal line (a suction containment boundary locus) as to each of the male/female rotors that have different tip diameters;
  • FIG. 7 gives an explanation about the male/female rotors that have different tip diameters;
  • FIG. 8 shows a perspective view as to a variation of the second embodiment;
  • FIGS. 1 a and 1 b schematically depict a bore face in a rotor casing of a screw compressor according to the present invention
  • FIG. 1 a shows a perspective view as to a suction seal line (a suction containment boundary locus) and a lip part on the bore face seen transparently from a top
  • FIG. 1 b is a development view of FIG. 1 a
  • the rotor-casing is divided into an upper side part and a lower side part so that the bore face of the casing is easily explained.
  • a suction seal line (a suction containment boundary locus) 5 is formed on a boundary between main bore faces 2 a / 2 b and expanded bore faces 3 a / 3 b , whereby the main bore faces 2 a / 2 b are located opposite to addendum circles of the a male rotor and a female rotor, with a slight clearance, while a lip part 4 as a protruding part is provided apart from the suction seal line 5 , by a screw pitch distance to a suction side end face 6 .
  • the suction seal line 5 includes a curved part 5 a that is on a main bore face of the male rotor side casing 1 a , a curved part 5 b that is on a main bore face of the female rotor side casing 1 b , and a curved part 5 c that is also on the main bore face of the female rotor side casing 1 b ; whereby, in the development figures of FIGS. 1 a and 1 b , the curved part 5 c is seen as a straight line which starts from a point “a” that is a cross point of the curved part 5 a and a bore intersection line 8 ; further, in FIGS. 1 a and 1 b , the straight line lies at right angles to the bore intersection line 8 , while the straight line ends a point where the line intersects with the curved part 5 b.
  • the geometry of the lip part 4 comprises:
  • Liquid such as oil or water injected into a compression working space is apt to leak toward a lower pressure suction side and accumulates in concaved expanded bore faces 3 a / 3 b .
  • the lip part 4 prevents the liquid from leaking and scattering toward a gas inlet side.
  • the distance between the suction seal line 5 and the lip part 4 is substantially within one screw pitch distance; thus, the lip part 4 is provided at a location closer to the suction seal line 5 in comparison with conventional ways. Therefore, in comparison with conventional ways, is effectively prevented a liquid leakage that scatters, during a compression process, from the compressed working space which is formed by the screw rotors toward the gas inlet side.
  • the lip part placed nearer to the suction seal line makes it possible to eliminate a part of the rotor casing, located at the gas inlet side from the lip part. So can be realized a simplified configuration of rotor casings with a reduced bore surface as well as a reduced suction resistance of an inhaled gas and an enhanced volumetric efficiency of the compressor.
  • a straight line portion 5 c of the suction seal line 5 is provided in the neighborhood of the bore intersection line, the line lying at right angles with the bore intersection line in a development view.
  • a thickened lip part 4 c is provided, comprising:
  • FIGS. 4 to 8 A second embodiment of the present invention is now detailed with reference to FIGS. 4 to 8 .
  • a male rotor and a female rotor of different rotor sizes namely different outer diameters, are used; where the outer diameter of the male rotor is larger than that of the female rotor, and the number of teeth as to the male rotor is 5 , while that as to the female rotor is 6 .
  • the reference numeral 11 denotes the rotor casing that accommodates both the male rotor and the female rotor, and the rotor casing 11 together with a gas inlet casing 13 that forms a gas inlet 12 is made of mono casting.
  • the rotor casing 11 accommodates the male rotor 22 and the female rotor 23 shown in FIG. 7 , here the detail of the rotors is omitted.
  • the reference numeral 14 denotes a male rotor shaft that is supported by a thrust bearing 16 and radial bearings 17 / 18
  • the numeral 15 denotes a female rotor shaft that is supported by a thrust bearing 19 and radial bearings 20 / 21 .
  • a mechanical seal 24 is provided near a shaft end part 14 a of the male rotor shaft 14 , the shaft end part 14 a being connected to an output shaft of a drive motor (not shown) as a power source.
  • a gas outlet casing 26 that forms a gas outlet 25 is made of casting; however, the casing 26 is made of different casting from the rotor casing 11 , and the casing 26 is fastened thereto with tightening bolts 27 .
  • a slide valve (a capacity control valve) 28 that makes it possible to regulate a compressor capacity (an inhaled gas capacity) by means of sliding-manipulation along an axis direction of the rotors; thereby, a pushrod (a driving rod) 29 regulates a length as to the sliding-manipulation of the slide valve 28 .
  • the pushrod 29 is operated through an oil pressure that is supplied to a left cylinder room 30 a and a right cylinder room 30 b in an oil-hydraulic cylinder 30 .
  • a U i -control device an internal volume ratio control device
  • the device 31 makes it possible to optimize the internal volume ratio U i .
  • a casing 35 that contains the U i -control device 31 is fastened to the gas inlet casing 13 with tightening bolts 36 , while the oil-hydraulic cylinder 30 is fitted to the casing 35 .
  • the reference numeral 37 denotes an internal volume ratio (U i ) adjusting valve; thereby, the U i -adjusting valve 37 is engaged into a screw part 38 a that is provided on an outer face of a hollow shaft 38 .
  • the hollow shaft 38 is installed around the pushrod 29 having a round cross-section, so that a round hollow cylinder of the hollow shaft 38 and the round cross-section of the pushrod 29 are concentric, and the hollow shaft 38 can rotate freely around the pushrod 29 . Further, the U i -adjusting valve 37 moves along the rotor axes with a rotational movement of the hollow shaft 38 .
  • the reference numeral 39 a denotes a bevel gear that is fitted to a suction-side end part of the hollow shaft 38 , while the bevel gear 39 a is engaged in a corresponding bevel gear 39 b that is fitted to an end part of a rotation-rod 40 ; hereupon, it is noted that the axes of the hollow shaft 38 and the rotation-rod 40 lie at right angles to each other.
  • the slide valve 28 is shifted along the axes of the rotors through a movement of the pushrod 29 ; thereby, a by-passed gas flow toward the gas inlet side from a gap between the slide valve 28 and the pushrod 29 controls the capacity (the inhaled gas flow quantity).
  • FIG. 6 shows the male rotor 22 , the female rotor 23 , and the suction seal line 32 in the second embodiment, in which the male rotor 22 and the female rotor 23 of different rotor sizes, namely, different outer diameters, are used, where the outer diameter of the male rotor is larger than that of the female rotor; in addition, the number of teeth as to the male rotor is 5 , while the number of teeth spaces as to the female rotor is 6 .
  • FIG. 4 are shown the suction seal line 32 and the lip part 33 , for explanation use. Similar to FIG. 1 as to the first embodiment, the lip part 33 is provided apart from the suction seal line 5 , by a screw pitch distance, toward the gas inlet side.
  • the suction seal line 32 comprises:
  • the lip part 33 comprises a male casing side lip part 33 a on the bore in the male rotor casing 11 a , and a female casing side lip part 33 b , while the boundary of the lip part 33 comprises a lip-entering-edge and a lip ending (trailing) edge; hereupon, the lip part 33 is away from the suction seal line, within a screw pitch distance.
  • the lip-ending-edge comprises:
  • a thickened lip part 33 c is formed with the bent curve portion 33 d and the line portion 33 e , in response to the straight line portion 32 c of the suction seal line 32 . So can be surely prevented a liquid leakage around the neighborhood along the bore intersection line, toward a gas inlet side, from the working (compression) spaces in the rotor casing 11 .
  • the lip part 33 is provided apart from the suction seal line 5 , by a screw pitch distance, toward the gas inlet side; thus, can be surely prevented a liquid leakage around the neighborhood along the bore intersection line, toward a gas inlet side, from the working (compression) spaces. Further, since the lip part is provided around the neighborhood along the bore intersection line as mentioned above, a liquid leakage around the bore intersection line can be surely prevented.
  • the location of the gas inlet 12 can be shifted toward the rotor casing 11 .
  • the rotor casing 11 together with a gas inlet casing 13 that forms a gas inlet 12 can be made of mono casting. In this way, a compact casing can be realized and a compressor installation space can be reduced. Consequently, a compact casing can be realized, a compressor installation space can be reduced, a compressor manufacturing cost can be greatly lowered, and the degree of freedom as to the gas inlet casing design about the rotor axis direction can be expanded.
  • an internal volume ratio (U i ) adjusting valve makes a whole compressor compact, realizing a compressor with three kinds of compression ratios , namely, of lower/medium/higher compression ratios, without changing sorts of a gas inlet casing, only by replacing a rotor casing.
  • a gas inlet casing can be applied to these kinds of compressors in common. Namely, even if the rotor-casing is replaced by another one for constituting a different kind (capacity) of the compressor, it is not necessary to exchange the gas inlet casing.
  • the second embodiment comprises a positioning means for positioning the internal volume ratio-adjusting valve including:
  • a driving mechanism to position the internal volume ratio-adjusting valve 37 can be formed as a compact one.
  • a crossed helical gear pair may be applied instead of a bevel gear pair; a bevel gear pair tends to have a play to some extent between meeting gears, while a crossed helical gear has little play.
  • a liquid leakage such as an oil leakage or a water leakage, that flows back to a gas inlet side from a compression room which is formed screw rotors is further effectively prevented in comparison with conventional compressors of the same kind.
  • suction resistance of the gas inhaled from the gas inlet can be lowered, and volumetric efficiency as to the inhaled gas can be improved; further, cast modeling of a rotor casing can be simplified and a manufacturing cost can be reduced.
  • the invention greatly contributes to a practical compressor industry.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
US12/111,624 2005-10-31 2008-04-29 Liquid injection type screw compressor Abandoned US20080253914A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2005/020041 WO2007052332A1 (fr) 2005-10-31 2005-10-31 Compresseur a vis a injection de liquide

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PCT/JP2005/020041 Continuation WO2007052332A1 (fr) 2005-10-31 2005-10-31 Compresseur a vis a injection de liquide

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US12/111,624 Abandoned US20080253914A1 (en) 2005-10-31 2008-04-29 Liquid injection type screw compressor

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US (1) US20080253914A1 (fr)
EP (1) EP1944513A4 (fr)
JP (1) JP4702639B2 (fr)
CA (1) CA2626884C (fr)
WO (1) WO2007052332A1 (fr)

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US20120201710A1 (en) * 2011-02-08 2012-08-09 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Water injection type screw compressor
US10844860B2 (en) * 2018-12-21 2020-11-24 Trane International Inc. Method of improved control for variable volume ratio valve
US20220112894A1 (en) * 2019-03-08 2022-04-14 Shimadzu Corporation Helical gear pump and helical gear motor

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120201710A1 (en) * 2011-02-08 2012-08-09 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Water injection type screw compressor
US8747091B2 (en) * 2011-02-08 2014-06-10 Kobe Steel, Ltd. Water injection type screw compressor
US10844860B2 (en) * 2018-12-21 2020-11-24 Trane International Inc. Method of improved control for variable volume ratio valve
US11725661B2 (en) 2018-12-21 2023-08-15 Trane International Inc. Method of improved control for variable volume ratio valve
US20220112894A1 (en) * 2019-03-08 2022-04-14 Shimadzu Corporation Helical gear pump and helical gear motor
US11773845B2 (en) * 2019-03-08 2023-10-03 Shimadzu Corporation Helical gear pump and helical gear motor

Also Published As

Publication number Publication date
EP1944513A1 (fr) 2008-07-16
JPWO2007052332A1 (ja) 2009-04-30
WO2007052332A1 (fr) 2007-05-10
CA2626884A1 (fr) 2007-05-10
EP1944513A4 (fr) 2013-05-29
JP4702639B2 (ja) 2011-06-15
CA2626884C (fr) 2012-01-24

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