US20160230760A1 - Positive displacement gear pump - Google Patents
Positive displacement gear pump Download PDFInfo
- Publication number
- US20160230760A1 US20160230760A1 US15/024,425 US201315024425A US2016230760A1 US 20160230760 A1 US20160230760 A1 US 20160230760A1 US 201315024425 A US201315024425 A US 201315024425A US 2016230760 A1 US2016230760 A1 US 2016230760A1
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- United States
- Prior art keywords
- pump
- rotor
- cylindrical body
- protuberances
- rotors
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
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Classifications
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- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
- F01C1/00—Rotary-piston machines or engines
- F01C1/08—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing
- F01C1/12—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type
- F01C1/123—Rotary-piston machines or engines 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 tooth-like elements, extending generally radially from the rotor body cooperating with recesses in the other rotor, e.g. one tooth
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- 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
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/0003—Sealing arrangements in rotary-piston machines or pumps
- F04C15/0023—Axial sealings for working fluid
- F04C15/0026—Elements specially adapted for sealing of the lateral faces of intermeshing-engagement type machines or pumps, e.g. gear machines or pumps
-
- 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
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/0088—Lubrication
-
- 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
- F04C18/123—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 radially or approximately radially from the rotor body extending tooth-like elements, co-operating with recesses in the other rotor, e.g. one tooth
-
- 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
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
-
- 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
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C2/123—Rotary-piston machines or pumps 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 radially or approximately radially from the rotor body extending tooth-like elements, co-operating with recesses in the other rotor, e.g. one tooth
-
- 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
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C2/14—Rotary-piston machines or pumps 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
- F04C2/20—Rotary-piston machines or pumps 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 dissimilar tooth forms
-
- 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
- F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
- F04C27/005—Axial sealings for working fluid
- F04C27/006—Elements specially adapted for sealing of the lateral faces of intermeshing-engagement type pumps, e.g. gear pumps
-
- 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
Definitions
- the present patent application for industrial invention relates to a positive displacement gear pump.
- FIG. 1 shows a positive displacement gear pump according to the prior art, generally indicated with reference numeral ( 101 ).
- the pump ( 101 ) comprises a casing ( 102 ) with suction pipe (I) and discharge pipe ( 0 ).
- Two identical rotors ( 103 ) are mounted inside the casing ( 102 ).
- Each rotor ( 103 ) comprises a gear composed of a toothed wheel.
- Each rotor comprises a plurality of linear or helicoidal teeth ( 130 ) that define a plurality of cavities ( 131 ) between said teeth ( 130 ).
- the two gears ( 103 ) are engaged in such manner that the teeth ( 130 ) of one gear are engaged into the cavities ( 131 ) of the other gear, and vice versa. So the fluid enters the suction pipe (I) and comes out of the discharge pipe (O).
- Vane pumps are additionally known, comprising a rotor provided with cavity in which vanes slide radially.
- the rotor is mounted eccentrically with respect to the seat of the casing where it is housed and the vanes are stressed by springs or by the centrifugal force towards the surface of the rotor housing.
- Said vane pumps permit a limited number of revolutions, cause early wear of vanes and require oil lubrication and consequently a separator to separate oil from the fluid treated by the pump.
- the purpose of the present invention is to overcome the drawbacks of the prior art, by disclosing a positive displacement gear pump capable of avoiding fluid encapsulation.
- Another purpose of the present invention is to obtain such a positive displacement gear pump that is able to operate with a high number of revolutions and is extremely reliable and safe.
- the positive displacement pump of the invention comprises:
- a casing that comprises a central body and two closing lids, said central body being provided with two communicating cylindrical chambers, one suction pipe and one discharge pipe, and
- the two rotors comprise:
- a male rotor that only comprises protuberances, not cavities, and
- a female rotor that only comprises cavities, not protuberances or teeth.
- the male rotor is engaged with the female rotor, i.e. the protuberances of the male rotor are engaged in the cavities of the female rotor without contact between the two rotors.
- FIG. 1 is cross-sectional view of a positive displacement gear pump according to the prior art
- FIG. 2 is an exploded perspective view of the positive displacement gear pump according to the invention
- FIG. 3 is a cross-sectional view of the pump of FIG. 2 in assembled condition
- FIG. 4 is an exploded view of a male rotor of the pump shown in FIG. 2 ;
- FIG. 5 is an exploded perspective view of an additional embodiment of the pump shown in FIG. 2 .
- a positive displacement pump according to the invention is disclosed, generally indicated with reference numeral ( 1 ).
- the pump ( 1 ) comprises a casing provided with central body ( 2 ) sealed by means of two plate-shaped closing lids ( 20 ).
- the central body ( 2 ) comprises two communicating cylindrical chambers ( 22 ; 23 ) in such manner to form a basically 8-shaped opening that is closed by the two lids ( 20 ).
- the central body is provided with two pipes (I, O) in communication with outside, respectively to suck and discharge the fluid treated by the pump.
- a male rotor ( 3 ) and a female rotor ( 4 ) are disposed in the cylindrical chambers ( 22 , 23 ) of the central body.
- the male rotor ( 3 ) comprises only protuberances ( 30 ), not cavities.
- the female rotor ( 4 ) comprises only cavities ( 40 ), not teeth or protuberances.
- the male rotor ( 3 ) is engaged with the female rotor, i.e. the protuberances ( 30 ) of the male rotor are engaged in the cavities ( 40 ) of the female rotor without contact between the two rotors.
- the male and female rotors ( 3 , 4 ) are mounted on corresponding shafts ( 5 , 6 ).
- the shafts ( 5 , 6 ) of the rotors are revolvingly supported on supports (bushes or bearings, not shown in the figures) provided in the seats ( 24 ) of the lids ( 20 ).
- the shaft ( 6 ) of the female rotor is connected to a drive shaft. Therefore, the female rotor ( 4 ) is the driving gear and the male rotor ( 3 ) is the driven gear.
- the shaft ( 5 ) of the male rotor can be connected to a drive shaft.
- both shafts ( 6 , 5 ) of the rotors can be simultaneously connected to two drive shafts in such manner to obtain better torque distribution.
- the pipes (I, O) of the central body can act as suction pipe or discharge pipe.
- two external gears ( 7 , 8 ) are disposed outside the casing and keyed to the shafts ( 5 , 6 ) of the rotors.
- the external gears ( 7 , 8 ) are engaging toothed wheels.
- the external gears allow for phasing the male and female rotors ( 3 , 4 ), meaning that during the rotation of the two rotors, the protuberances ( 30 ) of the male rotor enter the cavities ( 40 ) of the female rotor.
- the male rotor ( 3 ) comprises a cylindrical body ( 35 ) and a plurality of protuberances ( 30 ) radially protruding from the cylindrical body ( 35 ).
- Each protuberance ( 30 ) cross-sectionally comprises two involute-shaped sides ( 31 , 32 ) converging into a rounded head ( 33 ).
- the two sides ( 31 , 32 ) of a protuberance are symmetrical with respect to a radial axis of symmetry passing through the head ( 32 ) of the protuberance.
- the male rotor ( 3 ) comprises two protuberances ( 30 ) in diametrally opposite positions.
- the chamber ( 22 ) of the central body of the casing defines a suction area (A) in communication with the suction pipe (I) and a discharge area (B) in communication with the discharge pipe (O).
- the female rotor ( 4 ) comprises a cylindrical body ( 45 ) wherein a plurality of radially extending cavities ( 40 ) is obtained.
- Each cavity ( 40 ) cross-sectionally comprises two involute-shaped sides ( 41 , 42 ) joined into a bottom surface ( 43 ) with concave shape.
- the profiles of the two sides ( 41 , 42 ) of the cavity are not symmetrical with respect to a radial straight line passing through the bottom of the cavity.
- the involute-shaped profile of the inlet side ( 41 ) has a higher curvature than the involute-shaped profile of the outlet side ( 42 ) of the cavity.
- the female rotor ( 4 ) comprises two cavities ( 40 ) in diametrally opposite positions.
- the heads ( 33 ) of the protuberances of the male rotor are very close to the internal surface of the cylindrical chamber ( 22 ). During operation, the heads ( 33 ) of the protuberances of the male rotor arrive at a short distance from the bottom ( 43 ) of the cavity, thus avoiding the passage of liquid. However, the heads ( 32 ) do not touch the internal surface of the cylindrical chamber ( 22 ) or the bottom ( 43 ) of the cavity.
- the external surface of the cylindrical body ( 45 ) of the female rotor is almost tangent to the internal surface of the cylindrical chamber ( 23 ) of the central body of the casing, in such manner to avoid the passage of liquid.
- the external surface of the cylindrical body ( 45 ) of the female rotor is almost tangent to the external surface of the cylindrical body ( 35 ) of the male rotor.
- the male rotor ( 3 ) and female rotor ( 4 ) are perfectly centered in the corresponding cylindrical chambers ( 22 , 23 ) in such manner to leave a tolerance space of 0.05 mm, preferably 0.02 mm, between the following parts:
- FIG. 3 shows an additional embodiment, wherein the head diameter (meaning the distance between the heads ( 33 ) of two diametrally opposite protuberances) of the male rotor ( 3 ) is identical to the diameter of the cylindrical body ( 4 ) of the female rotor, in such manner to obtain two chambers ( 22 , 23 ) with identical diameter and make synchronization of the two rotors easier.
- the head diameter meaning the distance between the heads ( 33 ) of two diametrally opposite protuberances
- the diameter of the cylindrical body ( 35 ) of the male rotor can be identical to the diameter of the cylindrical body ( 45 ) of the female rotor.
- the peripheral speed of the two cylindrical bodies ( 35 , 45 ) of the two rotors is identical and the tolerance between cylindrical bodies ( 35 , 45 ) of the two rotors may be zero, thus allowing for contact between the cylindrical bodies ( 35 , 45 ) of the two rotors during rotation. Consequently, losses are minimized and high rotational speeds are allowed.
- the chamber ( 22 ) that houses the male rotor ( 3 ) is larger than the chamber ( 23 ) that houses the female rotor ( 4 ), thus increasing the delivery capacity of the pump ( 1 ), while maintaining the same size of the protuberance module ( 31 ).
- the male rotor ( 3 ) can be made in different parts that are mutually assembled.
- seats ( 36 ) are obtained in the cylindrical body ( 35 ), cross-sectionally having a substantially C-shaped or dovetail profile.
- the protuberances ( 30 ) consist in sectors provided with a substantially parallelepiped base ( 34 ) that is engaged into the seat ( 36 ).
- the base ( 34 ) of the protuberance can be provided with ribs or grooves ( 34 ′) that are engaged with corresponding ribs or grooves ( 36 ′) provided in the seat ( 36 ) of the cylindrical body of the male rotor.
- the entire rotors ( 3 , 4 ) or only the protuberances ( 30 ) and/or cavities ( 40 ) can undergo thermal and/or chemical treatments and can be coated with suitable materials, such as hard metal, Widia, rubber, plastics, Teflon or ceramic.
- the pump ( 1 ) also comprises two seal gaskets ( 9 ) composed of 8-shaped plates made of anti-friction self-lubricating material.
- the seal gaskets ( 9 ) are disposed between the central body ( 2 ) and the lids ( 20 ).
- the surface of the lids facing towards the central body is provided with suitable recessed seats ( 25 ) adapted to house the seal gaskets ( 9 ).
- Springs ( 90 ) are disposed in the seats ( 25 ) of the lids in such manner to stress the seal gaskets ( 9 ) towards the central body. In such a way, the seal gaskets ( 9 ) are stopped against the planar sides of the male and female rotors ( 3 , 4 ).
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Rotary Pumps (AREA)
- Details And Applications Of Rotary Liquid Pumps (AREA)
Abstract
A positive displacement pump (1) comprises a casing with a central body (2) and two closing lids (20), said central body (2) being provided with two cylindrical communicating chambers (22, 23), one suction pipe (I) and one discharge pipe (O), and two rotors (3, 4) revolvingly mounted in said chambers (22, 23) of the central body and supported by shafts (5, 6) revolvingly mounted in said closing lids (20). The two rotors comprise: a male rotor (3) comprising only protuberances (30), not cavities, and a female rotor (4) comprising only cavities (40), not teeth or protuberances.
Description
- The present patent application for industrial invention relates to a positive displacement gear pump.
- Various types of positive displacement pumps with internal gears are known on the market, being used to transport liquid or gaseous fluids from a suction pipe to a discharge pipe of the pump.
-
FIG. 1 shows a positive displacement gear pump according to the prior art, generally indicated with reference numeral (101). The pump (101) comprises a casing (102) with suction pipe (I) and discharge pipe (0). Two identical rotors (103) are mounted inside the casing (102). Each rotor (103) comprises a gear composed of a toothed wheel. Each rotor comprises a plurality of linear or helicoidal teeth (130) that define a plurality of cavities (131) between said teeth (130). - The two gears (103) are engaged in such manner that the teeth (130) of one gear are engaged into the cavities (131) of the other gear, and vice versa. So the fluid enters the suction pipe (I) and comes out of the discharge pipe (O).
- This type of positive displacement pumps of the prior art is impaired by drawbacks caused by fluid encapsulation. As a matter of fact, the fluid treated by the pump is trapped in the cavities of the rotor and compressed by the teeth of the other rotor, thus generating micro-explosions. Said micro-explosions considerably reduce the number of rotor revolutions, causing a considerable wear of the rotors and generating failure points in the rotor toothing.
- Vane pumps are additionally known, comprising a rotor provided with cavity in which vanes slide radially. The rotor is mounted eccentrically with respect to the seat of the casing where it is housed and the vanes are stressed by springs or by the centrifugal force towards the surface of the rotor housing.
- Said vane pumps permit a limited number of revolutions, cause early wear of vanes and require oil lubrication and consequently a separator to separate oil from the fluid treated by the pump.
- The purpose of the present invention is to overcome the drawbacks of the prior art, by disclosing a positive displacement gear pump capable of avoiding fluid encapsulation.
- Another purpose of the present invention is to obtain such a positive displacement gear pump that is able to operate with a high number of revolutions and is extremely reliable and safe.
- These purposes are achieved according to the invention with the characteristics claimed in the attached
independent claim 1. - Advantageous embodiments appear from the dependent claims.
- The positive displacement pump of the invention comprises:
- a casing that comprises a central body and two closing lids, said central body being provided with two communicating cylindrical chambers, one suction pipe and one discharge pipe, and
- two rotors revolvingly mounted in said chambers of the central body and supported by corresponding shafts revolvingly mounted and supported in said closing lids.
- The two rotors comprise:
- a male rotor that only comprises protuberances, not cavities, and
- a female rotor that only comprises cavities, not protuberances or teeth.
- The male rotor is engaged with the female rotor, i.e. the protuberances of the male rotor are engaged in the cavities of the female rotor without contact between the two rotors.
- The provision of male rotor and female rotor avoids fluid encapsulation in the cavities of the female rotor. Consequently, the pump of the invention can be used at a high number of revolutions, with minimum stress for mechanical moving parts.
- Additional characteristics of the invention will appear evident from the detailed description below, with reference to the attached drawings, which have an illustrative, not limitative purpose only, wherein:
-
FIG. 1 is cross-sectional view of a positive displacement gear pump according to the prior art; -
FIG. 2 is an exploded perspective view of the positive displacement gear pump according to the invention; -
FIG. 3 is a cross-sectional view of the pump ofFIG. 2 in assembled condition; -
FIG. 4 is an exploded view of a male rotor of the pump shown inFIG. 2 ; and -
FIG. 5 is an exploded perspective view of an additional embodiment of the pump shown inFIG. 2 . - Referring now to
FIGS. 2, 3 and 4 , a positive displacement pump according to the invention is disclosed, generally indicated with reference numeral (1). - The pump (1) comprises a casing provided with central body (2) sealed by means of two plate-shaped closing lids (20).
- The central body (2) comprises two communicating cylindrical chambers (22; 23) in such manner to form a basically 8-shaped opening that is closed by the two lids (20). The central body is provided with two pipes (I, O) in communication with outside, respectively to suck and discharge the fluid treated by the pump.
- A male rotor (3) and a female rotor (4) are disposed in the cylindrical chambers (22, 23) of the central body. The male rotor (3) comprises only protuberances (30), not cavities. Instead, the female rotor (4) comprises only cavities (40), not teeth or protuberances. The male rotor (3) is engaged with the female rotor, i.e. the protuberances (30) of the male rotor are engaged in the cavities (40) of the female rotor without contact between the two rotors. The male and female rotors (3, 4) are mounted on corresponding shafts (5, 6). The shafts (5, 6) of the rotors are revolvingly supported on supports (bushes or bearings, not shown in the figures) provided in the seats (24) of the lids (20).
- Preferably, the shaft (6) of the female rotor is connected to a drive shaft. Therefore, the female rotor (4) is the driving gear and the male rotor (3) is the driven gear. However, also the shaft (5) of the male rotor can be connected to a drive shaft. Moreover, both shafts (6, 5) of the rotors can be simultaneously connected to two drive shafts in such manner to obtain better torque distribution.
- According to the rotation direction of the drive shaft, the pipes (I, O) of the central body can act as suction pipe or discharge pipe.
- Advantageously, two external gears (7, 8) are disposed outside the casing and keyed to the shafts (5, 6) of the rotors. The external gears (7, 8) are engaging toothed wheels. The external gears allow for phasing the male and female rotors (3, 4), meaning that during the rotation of the two rotors, the protuberances (30) of the male rotor enter the cavities (40) of the female rotor.
- As shown in
FIG. 3 , the male rotor (3) comprises a cylindrical body (35) and a plurality of protuberances (30) radially protruding from the cylindrical body (35). Each protuberance (30) cross-sectionally comprises two involute-shaped sides (31, 32) converging into a rounded head (33). The two sides (31, 32) of a protuberance are symmetrical with respect to a radial axis of symmetry passing through the head (32) of the protuberance. - Advantageously, the male rotor (3) comprises two protuberances (30) in diametrally opposite positions. In such a case, the chamber (22) of the central body of the casing defines a suction area (A) in communication with the suction pipe (I) and a discharge area (B) in communication with the discharge pipe (O).
- The female rotor (4) comprises a cylindrical body (45) wherein a plurality of radially extending cavities (40) is obtained. Each cavity (40) cross-sectionally comprises two involute-shaped sides (41, 42) joined into a bottom surface (43) with concave shape. The profiles of the two sides (41, 42) of the cavity are not symmetrical with respect to a radial straight line passing through the bottom of the cavity. The involute-shaped profile of the inlet side (41) has a higher curvature than the involute-shaped profile of the outlet side (42) of the cavity.
- Advantageously, the female rotor (4) comprises two cavities (40) in diametrally opposite positions.
- The heads (33) of the protuberances of the male rotor are very close to the internal surface of the cylindrical chamber (22). During operation, the heads (33) of the protuberances of the male rotor arrive at a short distance from the bottom (43) of the cavity, thus avoiding the passage of liquid. However, the heads (32) do not touch the internal surface of the cylindrical chamber (22) or the bottom (43) of the cavity.
- Moreover, the external surface of the cylindrical body (45) of the female rotor is almost tangent to the internal surface of the cylindrical chamber (23) of the central body of the casing, in such manner to avoid the passage of liquid.
- Similarly, the external surface of the cylindrical body (45) of the female rotor is almost tangent to the external surface of the cylindrical body (35) of the male rotor.
- The male rotor (3) and female rotor (4) are perfectly centered in the corresponding cylindrical chambers (22, 23) in such manner to leave a tolerance space of 0.05 mm, preferably 0.02 mm, between the following parts:
- between the heads (33) of the protuberances of the male rotor and the internal surface of the cylindrical chamber (22) of the central body,
- between the heads (33) of the protuberances of the male rotor and the bottom surface (43) of the cavities of the female rotor,
- between the external surface of the cylindrical body (45) of the female rotor and the internal surface of the cylindrical chamber (23) of the central body of the casing,
- between the external surface of the cylindrical body (45) of the female rotor and the external surface of the cylindrical body (35) of the male rotor.
-
FIG. 3 shows an additional embodiment, wherein the head diameter (meaning the distance between the heads (33) of two diametrally opposite protuberances) of the male rotor (3) is identical to the diameter of the cylindrical body (4) of the female rotor, in such manner to obtain two chambers (22, 23) with identical diameter and make synchronization of the two rotors easier. However, when the diameter of the cylindrical body (35) of the male rotor (3) is smaller than the diameter of the cylindrical body (45) of the female rotor (4), a minimum tolerance must be provided between the two cylindrical bodies (35, 45) because the peripheral speeds of the two cylindrical bodies (35, 45) are different and a contact between them would cause a considerable friction, preventing the rotation of the two rotors. - In order to remedy such a drawback, the diameter of the cylindrical body (35) of the male rotor can be identical to the diameter of the cylindrical body (45) of the female rotor. In this way, the peripheral speed of the two cylindrical bodies (35, 45) of the two rotors is identical and the tolerance between cylindrical bodies (35, 45) of the two rotors may be zero, thus allowing for contact between the cylindrical bodies (35, 45) of the two rotors during rotation. Consequently, losses are minimized and high rotational speeds are allowed. Moreover, in such a case, the chamber (22) that houses the male rotor (3) is larger than the chamber (23) that houses the female rotor (4), thus increasing the delivery capacity of the pump (1), while maintaining the same size of the protuberance module (31).
- It must be noted that, because of the special configuration of the cavities (40) of the female rotor and because there are no contact parts between rotors (3, 4) and casing, the fluid is not trapped in the pump (1) and the pump (1) can operate at a high number of revolutions, thus reducing wear and failure of mechanical parts.
- As shown in
FIG. 4 , the male rotor (3) can be made in different parts that are mutually assembled. For instance, seats (36) are obtained in the cylindrical body (35), cross-sectionally having a substantially C-shaped or dovetail profile. - In such a case, the protuberances (30) consist in sectors provided with a substantially parallelepiped base (34) that is engaged into the seat (36). The base (34) of the protuberance can be provided with ribs or grooves (34′) that are engaged with corresponding ribs or grooves (36′) provided in the seat (36) of the cylindrical body of the male rotor.
- The entire rotors (3, 4) or only the protuberances (30) and/or cavities (40) can undergo thermal and/or chemical treatments and can be coated with suitable materials, such as hard metal, Widia, rubber, plastics, Teflon or ceramic.
- As shown in
FIG. 5 , the pump (1) also comprises two seal gaskets (9) composed of 8-shaped plates made of anti-friction self-lubricating material. The seal gaskets (9) are disposed between the central body (2) and the lids (20). The surface of the lids facing towards the central body is provided with suitable recessed seats (25) adapted to house the seal gaskets (9). Springs (90) are disposed in the seats (25) of the lids in such manner to stress the seal gaskets (9) towards the central body. In such a way, the seal gaskets (9) are stopped against the planar sides of the male and female rotors (3, 4). Such a solution provides for tightness of the chambers (22, 23) obtained inside the central body (20), thus avoiding losses due to construction tolerance. In this way, if the rotors (3, 4) are coated with anti-friction self-lubricating material, the pump (1) can be used at a high number of revolutions, without oil and with minimum wear for mechanical moving parts. - Variations and modifications can be made to the present embodiments of the invention, within the reach of an expert of the field, while still falling within the scope of the invention.
Claims (20)
1. A positive displacement pump comprising:
a casing comprising a central body and two closing lids, said central body being provided with two communicating cylindrical chambers, one suction pipe and one discharge pipe, and
two rotors revolvingly mounted in said chambers of the central body and supported by corresponding shafts revolvingly mounted in said closing lids,
characterized in that said two rotors comprise:
a male rotor having an outer surface that comprises protuberances said outer surface being substantially free of cavities, and
a female rotor having an outer surface that comprises cavities said outer surface being substantially free of protuberances and teeth,
wherein the protuberances of the male rotor are engaged in the cavities of the female rotor without contact between the two rotors.
2. The pump of claim 1 , wherein said male rotor comprises a cylindrical body and a plurality of protuberances that protrude radially from the cylindrical body and said female rotor comprises a cylindrical body and a plurality of cavities that extend radially inside the cylindrical body.
3. The pump of claim 2 , wherein
each protuberance of the male rotor cross-sectionally comprises two involute-shaped sides converging into a rounded head, the two sides of each protuberance being symmetrical with respect to a radial axis of symmetry passing through the head of the protuberance, and
each cavity cross-sectionally comprises two involute-shaped sides joined into a bottom surface with concave shape, wherein the profiles of the two sides of the cavity are asymmetrical with respect to a radial straight line passing through the bottom of the cavity, the involute-shaped profile of the inlet side having a higher curvature than the involute-shaped profile of the outlet side of the cavity.
4. The pump of claim 3 , wherein the male and female rotors are centered in the chambers of the central body in such manner to leave a tolerance space of between 0.05 mm, and 0.02 mm, between the following parts:
between the heads of the protuberances of the male rotor and the internal surface of the cylindrical chamber of the central body,
between the heads of the protuberances of the male rotor and the bottom surface of the cavities of the female rotor,
between the external surface of the cylindrical body of the female rotor and the internal surface of the cylindrical chamber of the central body of the casing,
between the external surface of the cylindrical body of the female
rotor and the external surface of the cylindrical body of the male rotor.
5. The pump of claim 1 , wherein the male rotor comprises two diametrally opposite protuberances and the female rotor comprises two diametrally opposite cavities.
6. The pump of claim 1 , wherein the protuberances of the male rotor are provided with heads and the head diameter of the male rotor is identical to the diameter of the cylindrical body of the female rotor.
7. The pump of claim 2 , wherein the diameter of the cylindrical body of the male rotor is identical to the diameter of the cylindrical body of the female rotor.
8. The pump (1) of claim 1 , wherein the male rotor comprises a cylindrical body provided with seats and said protuberances consist in sectors comprising a base that is engaged in the seat of the cylindrical body of the rotor.
9. The pump of claim 1 , further comprising two external gears comprising toothed wheels keyed onto the shafts of the rotors outside said casing.
10. The pump of claim 1 , also further comprising:
two plate-shaped seal gaskets disposed between said central body and said lids and
a plurality of springs disposed between said lids and seal gaskets in such manner to stress the seal gaskets against the planar sides of the rotors.
11. The pump of claim 10 , wherein said seal gaskets and said rotors are coated with an anti-friction self-lubricating material.
12. The pump of claim 3 , wherein the male rotor comprises two diametrally opposite protuberances and the female rotor comprises two diametrally opposite cavities.
13. The pump of claim 3 , wherein the protuberances of the male rotor are provided with heads and the head diameter of the male rotor is identical to the diameter of the cylindrical body of the female rotor.
14. The pump of claim 3 , wherein the diameter of the cylindrical body of the male rotor is identical to the diameter of the cylindrical body of the female rotor.
15. The pump of claim 3 , wherein the male rotor comprises a cylindrical body provided with seats and said protuberances consist in sectors comprising a base that is engaged in the seat of the cylindrical body of the rotor.
16. The pump of claim 3 , further comprising:
two plate-shaped seal gaskets disposed between said central body and said lids; and
a plurality of springs disposed between said lids and seal gaskets in such manner to stress the seal gaskets against the planar sides of the rotors.
17. The pump of claim 16 , wherein said seal gaskets and said rotors are coated with an anti-friction self-lubricating material.
18. The pump of claim 6 , wherein the male rotor comprises a cylindrical body provided with seats and said protuberances consist in sectors comprising a base that is engaged in the seat of the cylindrical body of the rotor.
19. The pump of claim 6 , further comprising:
two plate-shaped seal gaskets disposed between said central body and said lids; and
a plurality of springs disposed between said lids and seal gaskets in such manner to stress the seal gaskets against the planar sides of the rotors.
20. The pump of claim 19 , wherein said seal gaskets and said rotors are coated with an anti-friction self-lubricating material.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/IT2013/000260 WO2015044969A1 (en) | 2013-09-27 | 2013-09-27 | Positive displacement gear pump |
Publications (1)
Publication Number | Publication Date |
---|---|
US20160230760A1 true US20160230760A1 (en) | 2016-08-11 |
Family
ID=49817191
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/024,425 Abandoned US20160230760A1 (en) | 2013-09-27 | 2013-09-27 | Positive displacement gear pump |
Country Status (7)
Country | Link |
---|---|
US (1) | US20160230760A1 (en) |
EP (1) | EP3049622A1 (en) |
CN (1) | CN105593467A (en) |
CA (1) | CA2924421A1 (en) |
CH (1) | CH708632B1 (en) |
RU (1) | RU2638113C2 (en) |
WO (1) | WO2015044969A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107476827A (en) * | 2017-10-13 | 2017-12-15 | 封海涛 | Novel rotary steam engine |
US20200025241A1 (en) * | 2018-07-23 | 2020-01-23 | Hamilton Sundtrand Corporation | High efficiency gear pump bearing assembly |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108953147A (en) * | 2018-07-28 | 2018-12-07 | 周信城 | cam compressor |
KR102311679B1 (en) * | 2020-03-11 | 2021-10-08 | 김찬원 | A Vacium Self-priming Pump |
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US1052045A (en) * | 1912-02-20 | 1913-02-04 | Andrew G Doedyns | Rotary engine. |
US2920610A (en) * | 1955-04-01 | 1960-01-12 | Inst Francais Du Petrole | Rotary internal combustion engine |
US4457680A (en) * | 1983-04-27 | 1984-07-03 | Paget Win W | Rotary compressor |
US4526518A (en) * | 1981-07-23 | 1985-07-02 | Facet Enterprises, Inc. | Fuel pump with magnetic drive |
US6129067A (en) * | 1997-11-28 | 2000-10-10 | Riley; Thomas | Rotary engine |
US20110311386A1 (en) * | 2010-06-16 | 2011-12-22 | Kevin Thomas Hill | Pumping Systems |
US8517706B2 (en) * | 2002-05-06 | 2013-08-27 | Jerome R. Lurtz | Non-eccentric engine |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB749569A (en) * | 1954-04-15 | 1956-05-30 | Karsten Alfred Ovretveit | Improvements in or relating to rotary fluid pumps and motors and the like |
IT1287464B1 (en) * | 1996-07-29 | 1998-08-06 | Giovanni Morselli | VOLUMETRIC ROTARY MACHINE |
RU2458251C2 (en) * | 2010-10-19 | 2012-08-10 | Сергей Васильевич Алешин | Compressor |
-
2013
- 2013-09-27 CA CA2924421A patent/CA2924421A1/en active Pending
- 2013-09-27 CN CN201380079792.XA patent/CN105593467A/en active Pending
- 2013-09-27 EP EP13811014.3A patent/EP3049622A1/en not_active Withdrawn
- 2013-09-27 US US15/024,425 patent/US20160230760A1/en not_active Abandoned
- 2013-09-27 RU RU2016115597A patent/RU2638113C2/en not_active IP Right Cessation
- 2013-09-27 WO PCT/IT2013/000260 patent/WO2015044969A1/en active Application Filing
-
2014
- 2014-09-23 CH CH01436/14A patent/CH708632B1/en not_active IP Right Cessation
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1052045A (en) * | 1912-02-20 | 1913-02-04 | Andrew G Doedyns | Rotary engine. |
US2920610A (en) * | 1955-04-01 | 1960-01-12 | Inst Francais Du Petrole | Rotary internal combustion engine |
US4526518A (en) * | 1981-07-23 | 1985-07-02 | Facet Enterprises, Inc. | Fuel pump with magnetic drive |
US4457680A (en) * | 1983-04-27 | 1984-07-03 | Paget Win W | Rotary compressor |
US6129067A (en) * | 1997-11-28 | 2000-10-10 | Riley; Thomas | Rotary engine |
US8517706B2 (en) * | 2002-05-06 | 2013-08-27 | Jerome R. Lurtz | Non-eccentric engine |
US20110311386A1 (en) * | 2010-06-16 | 2011-12-22 | Kevin Thomas Hill | Pumping Systems |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107476827A (en) * | 2017-10-13 | 2017-12-15 | 封海涛 | Novel rotary steam engine |
US20200025241A1 (en) * | 2018-07-23 | 2020-01-23 | Hamilton Sundtrand Corporation | High efficiency gear pump bearing assembly |
US10731701B2 (en) * | 2018-07-23 | 2020-08-04 | Hamilton Sunstrand Corporation | High efficiency gear pump bearing assembly |
Also Published As
Publication number | Publication date |
---|---|
CH708632B1 (en) | 2018-06-29 |
WO2015044969A1 (en) | 2015-04-02 |
WO2015044969A8 (en) | 2015-10-22 |
CH708632A2 (en) | 2015-03-31 |
RU2638113C2 (en) | 2017-12-11 |
RU2016115597A (en) | 2017-10-26 |
CN105593467A (en) | 2016-05-18 |
EP3049622A1 (en) | 2016-08-03 |
CA2924421A1 (en) | 2015-04-02 |
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