US2705922A - Fluid pump or motor of the rotary screw type - Google Patents

Fluid pump or motor of the rotary screw type Download PDF

Info

Publication number
US2705922A
US2705922A US346844A US34684453A US2705922A US 2705922 A US2705922 A US 2705922A US 346844 A US346844 A US 346844A US 34684453 A US34684453 A US 34684453A US 2705922 A US2705922 A US 2705922A
Authority
US
United States
Prior art keywords
rotor
casing
thread
port
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.)
Expired - Lifetime
Application number
US346844A
Inventor
Rathman Gilbert
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.)
Dresser Industries Inc
Original Assignee
Dresser Industries Inc
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 Dresser Industries Inc filed Critical Dresser Industries Inc
Priority to US346844A priority Critical patent/US2705922A/en
Application granted granted Critical
Publication of US2705922A publication Critical patent/US2705922A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04CROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00Rotary-piston machines or pumps
    • F04C2/08Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/12Rotary-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
    • F04C2/14Rotary-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
    • F04C2/16Rotary-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 helical teeth, e.g. chevron-shaped, screw type

Description

G. RATHMAN April 12, 1955 FLUID PUMP OR MOTOR OF THE ROTARY SCREW TYPE Filed April 6. 1953 5 Sheets-Sheet 1 INVENTOR ATTORNEXQSY G. RATHMAN FLUID PUMP OR MOTOR OF THE ROTARY SCREW TYPE Filed April 6. 1953 5 Sheets-Sheet 2 1N VENTOR G Lbr Rathman BY @mm1/,MPM
ATTORNEKS April 12, 1955 G. RATHMAN 2,705,922
FLUID PUMP OR MOTOR OF' THE ROTARY SCREW TYPE asv/. l .26
coMPREssoN RATIO- coMPREssloN RATIO coMPREssloN RATIO INVENTOR Gil/bert Rai/unan Carnahan/7mm sv/Zan ATTORNEYS G. RATHMAN April 12, 1955 FLUID PUMP OR MOTOR OF THE ROTARY SCREW TYPE Filed April 6, 1953 5 Sheets-Sheet 4 1N VENTOR ATTORNEYS' G. RATHMAN April 12, 1955 FLUID PUMP OR MOTOR OF THE ROTARY SCREW TYPE Filed April e, 1953 5 shets-sheet 5 INVENTOR G Lber Ralunan/ BY @WWW/,Mm Wm ATTORN E YLS United StatesA Patent O FLUID PUMP GR MOTR F THE ROTARY SCREW TYPE Gilbert Rathman, Union, N. J., assigner to Dresser Industries, Inc., Bradford, Pa., a corporation of Pennsyl vanta Application April 6, 1953, Serial No. 346,844
16 Ciams. (Cl. 10S-12S) This invention relates to rotary screw pumps and motors of the positive displacement type comprising intermeshing, helically ribbed rotors which are adapted either for transporting or compresing uids, or for operation as ex pansible fluid engines, and is particularly directed to apparatus of this character wherein each rotor rib or thread is half male and half female, i. e., convex on one side and concave on the other side. For examples of the forms ot rotors to which the invention pertains, reference may be had to Nuebling Patent No. 1,233,599, dated July 17, and my own Patent No. 2,511,878, dated lune 20,
Although the devices of the present invention are reversible in operation so as to function with equally high efficiency as either pumps or motors, the following descn'ption will, in the interest of simplicity, designate said devices as pumps or blowers and use phraseolog generally applicable to air blowers and compressors. By so doing, however, it is not intended to limit the scope of the invention to pumps, blowers and compressors, even though it is in this field that the inventive concept would appear to iind its greatest utility at the present time.
The pump disclosed in my above idenied patent, upon which the present invention is an improvement, is characterized by the combination of a pair of coacting rotors, each having a single helical rib or thread convex on one side and concave on the other, which rotate in intermeshed relation with a one-to-one gear ratio in a casing continuously open at the inlet end to a source of low pressure iiuid and having intermittent connection at the other end with a discharge conduit wherein an equal or higher pressure prevails. Communication between the discharge conduit and the fluid transporting and compressing spaces defined by the rotor ribs is controlled in such a manner that the iiuid is confined in said spaces until the desired pressure is built up, whereupon, once in every revolution of the rotors, each space is opened to the discharge conduit through a passageway or port which faces, and lies within the axially projected cross section of, the threaded portion of that rotor which has the concave side of its thread facing the discharge end of the pump. The latter rotor may conveniently be called the discharge or driving rotor, while the other is known as the mating or driven rotor.
In this earlier type of pump, the discharge of fluid from the rotors is in an axial direction and is controlled by a discharge port in the end wall of the casing of predetermined coniiguration and volumetric capacity which is opened and closed periodically by rotation of the discharge rotor itself, the end of the rotor rib or thread serving to cover and uncover the port as the rotor turns. With this construction, it is possible to maintain a constant iiow ot gas or other fluid into the discharge line at a predetermined pressure without objectionable surging or other variable pressure conditions in the fluid at the discharge end of the pump, and to obtain an adiabatic internal compression up to at least a 3:1 ratio, or a discharge pressure of 30 pounds per square inch or more (gauge).
One of the objects of the present invention is to provide an improved form of screw type pump or motor embodying half male, half female rotor threads which, for compression or expansion ratios of about 2:1 or less, is of smaller size, less weight and lower cost, and is capable of higher rotational speeds, than the construction represented by the above mentioned Patent No. 2,511,878.
Another object is to provide a blower or compressor of the character described with radially disposed intake and 8 0 Patented Apr. 12, 1955 discharge ports of novel construction which are especially designed with reference to the form of the rotors to provide the compression ratio desired.
A further object is to provide a pump of the rotary screw type having a built-in compression ratio of not more than about 2:1 embodying improved means for discharging the compressed liuid and preventing the entrapment thereof between the rotors and the discharge end of the casing.
These and other objects, including provision of a device of the character described which is reversible in operation with no loss in eflciency, will appear more fully upon consideration of the detailed description of certain embodiments of the invention which follows. Although several specifically diiferent structures are described and illustrated in the accompanying drawings, it is to be expressly understood that these drawings are exemplary only and are not to be construed as dening the limits of the invention, for which latter purpose reference should be had to the appended claims.
Referring now to the drawings, wherein like reference characters indicate like parts throughout the several views and all of the Views are at least partially diagrammatic:
Fig. l is a side view of one form of screw pump or compressor embodying the invention with the inlet side of the casing removed and with portions of the rotors shown in vertically axial section;
Figs. 2 and 3 are plan and end elevation views, respectively, of the device shown in Fig. 1;
Fig. 4 is an irregular transverse sectional View of the construction of Figs. l-3 taken approximately on the line 4 4 in Fig. 2;
Fig. 5 is a side view of the pump of Figs. 1-4 taken from the discharge side with the portion of the casing which defines the discharge port broken away so as to show the configuration of said port in relation to the rotor threads;
Figs. 6a, 6b and 6c are diagrams indicating how the size of the discharge port may be varied in order to vary the compression ratio;
Fig. 7 is a plan View of the device of Figs. 1 6 with the casing shown in section, the section being taken substantially on the line 7 7 in Fig. 1;
Fig. 8 is a sectional view of the structure of Fig. 7 taken substantially on the line 8 3 in the latter gure;
Fig. 9 is a fragmentary view similar to Fig. 7 of the discharge end of another embodiment of the invention, the sectioning of the casing in this view being irregular in order to better illustrate the construction involved;
Fig. l0 is a sectional view of the structure of Fig. 9 talen substantially on the line 10-10 in the latter iigure; an
Figs. 1l and 12 are views similar to Figs. 9 and 10, respectively, of a third construction embodying the invention.
Referring now to Figs. 1-5, 7 and 8, the pump structure shown therein comprises a casing made up of two complementary side sections 21 and 22 and a pair of end sections or heads 23 and 24 provided with supporting bases 25 and 26, respectively, the two side sections being removably secured to one another along a vertical plane passing through the axes of the pump rotors in any suitable manner, as by anges and bolts (not shown), while the end sections 23 and 24 are similarly connected to the anged ends of the side sections. As shown best in Figs. 3 and 4, the main body of the casing formed by the two side sections is substantially 3-shaped in cross section, consisting of a pair of hollow cylinders in partially overlapped relation with their axes parallel and vertically ottset from one another. Side section 21 carries adjacent one end thereof a laterally projecting fluid intake conduit 27, while side section 22 is provided with a similar fluid discharge conduit 28 adjacent the other end of the casing.
Housed in each of casing heads 23 and 24 are a pair of combination radial and end thrust bearings 29 which rotatably support the shafts 30 and 3l of a pair of intermeshed, helically threaded rotors 32 and 33 adapted, in known manner, to transport air, gas or other iluid from the intake conduit 27, through the casing and out through the discharge conduit 28, and at the same time to compress the uid prior to discharge. The shaft 30 of rotor 32, hereinafter referred to as the driving or discharge rotor, projects outwardly of casing head 23 at the intake end of the casing, and is adapted to be connected to a suitable source of power for turning the driving rotor in the direction indicated by the arrows in the iigures. The shaft 31 of the second rotor 33, hereinafter referred to as the driven or mating rotor, is drivably connected to shaft 30 of the driving rotor by means of gears 34 housed in casing head 23 which are adapted to rotate both rotors at the same speed.
'Ihe rotors 32 and 33 are keyed to their respective shafts 30 and 31 for rotation therewith, and are held against axial movement along said shafts, to the right as viewed in Fig. 1, by stop shoulders 35 and 36 formed on the shafts. The driving rotor 32 is provided with a single helical thread or rib 37 having at least one full turn or convolution, the outer peripheral surface of which has a running fit in the upper portion of the casing formed by side sections 21 and 22. The driven rotor 33 is similarly provided with a thread or rib 38 of the same length as the thread 37 and having a running t in the lower portion of the casing.
As best illustrated in Fig. l, each of the threads or ribs 37 and 38 is concave in longitudinal cross section at one side, while the opposite side is convex; i. e., each thread is half male and half female. For example, the left side 39 of the driving thread 37 is concave, as viewed in Fig. l, while the right side 40 is convex, or substantially so. The driven thread 38 is oppositely formed in that its left side 41 is convex, or practically convex, while the right side 42 is concave. The result is that the two rotors are so formed that the similarly shaped sides of the threads face one another, and that the concave side 39 of driving thread 37 of the discharge rotor faces the end wall formed by casing head 24 at the discharge end of the casing. It will also be noted that, in this form of rotor construction, which is the subject matter of my previously mentioned Patent No. 2,511,878, thread 37 of the discharge rotor is relatively thin in an axial direction in comparison with thread 38 of the driven rotor, and that the groove 43 between the turns of thread 37 is correspondingly wider than the groove 44 of the driven rotor.
By reference to Fig. 4, it will be seen that each rotor exhibits in any section perpendicular to its axis a compound curved outline consisting of an outer peripheral surface 45 of cylindrical curvature conforming to the curvature of the inside wall of the casing in which it rotates, an inner root or dedendum circle 46 concentric with the associated rotor shaft, a concave side 47 connecting one end of the outer peripheral surface 45 with oneend of the exposed portion of the root circle 46, and a curvex side 48 connecting the other end of the peripheral surface with the root circle. The concave side 47 of the thread is of epicycloidal shape, while the convex side 48 has a curvature substantially that of an Archimedean spiral.
The stop shoulders 3S and 36 on the rotor shafts are located, as shown in Figs. l and 7, a substantial distance inwardly from the wall of casing head 23 which closes the intake end of the casing so as to provide a relatively large uid intake chamber 49 which is in permanently open, direct communication with the uid intake conduit 27 and also communicates with the intake ends of the fluid transporting and compressing spaces 50 dened by the rotor threads 37 and 38 and the surrounding wall of the casing. In accordance with the present invention, communication between intake conduit 27 and intake chamber 4-9 is provided by an intake port 51 which is formed by a radially outwardly dished or odset portion of the Wall of side section 21 of the casing and is of substantially greater area than intake conduit 27. As indicated by the broken lines in Fig. l, intake port 51 has an area almost half that of casing side section 21 and is of irregular shape conforming in part to the peripheral edges of the rotor threads.
In the form shown, port 51 has an end edge a parallel to and located in substantially the same plane with thc inner face of the wall formed by casing head 23, a pair of parallel side edges b and c substantially coincident withthe upper and lower edges of side section 2l, and another end edge of irregular form dened by two lines d and e parallel to the peripheral edges of rotor threads 37 and 38, respectively, which converge toward the opposite casing head 24 but do not intersect, and a third line f parallel to the rotor axes connecting the other two lines, said third line f lying closer to the axis of driven rotor 33 than to the axis of driving rotor 32. If desired, the two side edges b and c of the intake port may be brought closer together than in the embodiment illustrated, although their spacing should be maintained at least as great as the distance between the rotor axes. The axial dimensions of port 51 may also be varied as described, as long as they are not increased to the point where there is direct communication through the fluid transporting and compressing spaces 50 between intake port 51 and the discharge port 52 next to be described.
As in the case of the intake port, discharge port 52 is formed by a radially outwardly dished portion of casing side section 22 and is of a shape directly related to and dependent upon the form of the rotor threads. The size or area of port 52 establishes the compression ratio of the device. In the structure shown in Figs. l-5, the discharge port has been given its maximum permissible size corresponding to a 1:1 compression ratio, i. e., the case in which the pump acts solely as a uid transport mechanism without internal compression.
As shown best in Fig. 5, port 52 has one edge g parallel to and substantially coplanar with the wall formed by casing head 24 at the discharge end of the casing against which the discharge ends of rotor threads 37 and 38 abut, the remaining edges being delined by two nonintersecting lines h and i parallel to the peripheral edges of the rotor threads, line h intersecting edge g closely adjacent the lower edge of casing section 22, a third line j parallel to the rotor axes connecting the adjacent ends of lines h and i and having a length less than the axial dimension of the outer peripheral surface of thread 37 of the driving rotor and lying closer to the axis of said rotor than to the axis of driven rotor 33, and a fourth line k substantially coincident with the upper edge of zasing section 22 joining edge g and the upper end of ine z.
In order to determine the locations of lines h, i and j, the rotors are turned to the position wherein the portion of fluid transporting and compressing space 50 adjacent casing head 24 at the discharge end of the device has just been cut of from communication with intake port 51; i. e., when the rotors reach the position where they are about to begin compression of the fluid contained in that portion of space 50 which is confined between the end wall formed by casing head 24 and the last half convolutions of the rotor threads adjacent said wall. At this time, the end of the leading edge of driving rotor thread 37 lies in the plane of the rotor axes adjacent the side wall of the casing at the top thereof, while the end of the trailing edge of driven rotor thread 3S lies in the same plane adjacent the casing side wall at the bottom thereof. With the rotors in this position, i. e., the position shown in Fig. 5, the maximum permissible size of discharge port 52 is defined by the traces upon the inner surface of casing side section 22 of the trailing peripheral edges l and m of the last half convolutions of the rotor threads adjacent the casing head 24 and a line joining said traces parallel to the rotor axes lying closer to the axis of driving rotor 32 than to the axis of driven rotor 33. While this method will provide the theoretically correct, maximum permissible size of discharge port, it is preferable, in order to insure adequate sealing between the intake and discharge ports, to make the discharge port smaller than the theoretically correct maximum, as has been done in Fig. 5, by locating the edges h and 1' of the port slightly closer to casing head 24 than the traces of trailing edges l and m of threads 37 and 38, respectively.
In order to establish the shape and size of discharge port 52 for any compression ratio between 1:1 and 2:1, it is only necessary to place the rotors in the position wherein the uid pocketed between the rotor threads and the end wall 24 has been compressed to the desired pressure and then trace the trailing edges of the discharge ends of the rotor threads in the manner above described, again preferably reducing the size of the port slightly below the theoretically correct size to insure proper sealing. See, for example, the diagrams of Figs. 6a, 6b and 6c wherein have been indicated the relative shapes and sizes of discharge port for compression ratios of 1:1, 8:5 and 2:1, respectively. ln each instance, it will be noted that the major portion of the area of the discharge port lies radially opposite the unmeshed portion of thread 37 of the driving rotor 32.
said rst port, a second port formed entirely in the side wall of said casing adjacent the other end thereof and providing communication between the iiuid receiving space and said second conduit, and a second wall perpen dicular to the axes of said rotors closing the end of said `casing adjacent said second port and facing the concave and convex sides of the threads of the first and second rotors, respectively, said second port having one edge parallel to and in substantially the same plane as said second wall and another edge of irregular form defined by two non-intersecting lines parallel to the peripheral edges of the respective rotor threads and converging toward said first Wall and a third line parallel to the rotor axes connecting the other two lines, said third line having a length less than the axial dimension of the outer peripheral surface of the thread of the first rotor and lying closer to the axis of said first rotor than to the axis of the second rotor.
2. A rotary screw type fluid pump or motor as defined in claim l wherein the maximum size of said second port is defined by the trailing edges of the last half convolutions of the rotor threads adjacent the second wall when the rotors are so positioned that the end of the leading edge of the thread of the first rotor lies in the same plane as the rotor axes and adjacent the side wall of the casmg.
3. A rotary screw type iiuid pump or motor as defined in claim 1 including a passageway in the second wall leading from a point opposite the unmeshed portion of the thread of the first rotor, adjacent the hub of said rotor and the periphery of the thread of the second rotor, to the second conduit, said passageway being adapted to pass fiuid between the fluid receiving space and said second conduit independently of the second port.
4. A rotary screw type uid pump or motor as defined in claim 3 wherein said passageway consists of a curved groove in said second wall paralleling the periphery of the thread of the second rotor and extending from a point opposite the hub of said first rotor to a point opposite the periphery of the thread thereof.
5. A rotary screw type fluid pump or motor as defined in claim 3 wherein each rotor thread exhibits in any section perpendicular to its axis a compound curved outline defined by a portion of the root circle of said thread, a port-ion of the cylindrical periphery thereof and two curves, one concave and the other convex, connecting said portions of the root circle and cylindrical periphery, and wherein said passagewav consists of a recess in said second wall having an outline defined by two lines substantially coincident with portions of the root circle and cylindrical periphery of the thread of said first rotor, a third line substantially coincident with the convex curve of the outline of the thread of said first rotor, and a fourth line substantially coincident with a portion of the cylindrical periphery of the thread of said second rotor, the side of said recess defined by the line substantially coincident with a portion of the cylindrical periphery of said rst rotor being open to sa-id second conduit.
6. A rotary screw type fluid pump or motor as defined in claim l wherein said first port has one end edge parallel to and adjacent the plane of said first wall, a pair of side edges parallel to and spaced apart further than the axes of said rotors, and another end edge of irregular form defined by two non-intersecting lines parallel to the peripheral edges of said rotor threads and converging toward said second wall and a third line parallel to the rotor axes connecting the other two lines, said third line lying closer to the axis of said second rotor than to the axis of said first rotor.
7. A rotary screw type fluid pump comprising a pair of intermeshing helically threaded rotors interconnected to drive one rotor from the other at a one-to-one ratio, each of said rotors having a thread which is convex on one side and concave on the opposite side and has an outer peripheral surface of helically cylindrical form. said rotors being so intermeshed that the concave and convex sides of the thread on the first rotor face the concave and convex sides, respectively, of the thread on the second rotor, a casing for said rotors having a side wall cooperating with the rotor threads to form a fiuid pumping space and end walls preventing the ingress and egress of fluid in an axial direction, fiuid inlet and outlet conduits connected to said casing, a iiuid inlet port formed entirely in the side wall of said casing adjacent one end thereof providing communication between the inlet conduit and the iiuid pumping space defined by the rotor threads and the casing, and a iiuid outlet port formed entirely in the side Wall of said casing on the side opposite the inlet port adjacent the other end of said casing and providing communication between said fiuid pumping space and the outlet conduit, the shape and size of said outlet port for any given outlet pressure of the iiuid being defined substantially by the end wall of the casing at the outlet end thereof and the traces upon the side wall of the trailing peripheral edges of the last half convolutions of the rotor threads adjacent said end wall.
8. A rotary screw type fiuid pump as defined in claim 7 wherein the maximum size of said outlet port is defined by the traces upon the side wall of the trailing peripheral edges of the last half convolutions of the rotor threads adjacent the end wall of the casing at the outlet end thereof when the rotors are so positioned that the end of the leading edge of the thread of the first rotor lies in the same plane as the rotor axes and adjacent the side wall of the casing.
9. A rotary screw type iiuid pump as defined in claim 7 including a relief passageway in the end wall of the casing at the outlet end thereof for venting the fluid pocketed in the fluid pumping space between said end wall and the end of the thread of said first rotor during the partial rotation of said rotors immediately following closure of communication between said pumping space and the outlet port.
l0. A rotary screw type iiuid pump as defined in claim 9 wherein the relief passageway leads from a point opposite the unmeshed portion of the thread of the first rotor, adjacent the hub of said rotor and the periphery of the thread of the second rotor, to the outlet conduit, said passageway being adapted to pass fluid from the iiuid pumping space to said outlet conduit independently of the outlet port.
ll. A rotary screw type iiuid pump as dened in claim 9 wherein said relief passageway consists of a curved groove in the end wall of the casing at the outlet end thereof paralleling the periphery of the thread of the second rotor and extending from a point opposite the hub of said first rotor to a point opposite the periphery of the thread thereof.
l2. A rotary screw type uid pump as defined in claim 9 wherein each rotor thread exhibits in any section perpendicular to its axis a compound curved outline defined by a portion of the root circle of said thread, a portion of the cylindrical periphery thereof and two curves, one concave and the other convex, connecting said portions of the root circle and cylindrical periphery, and wherein said relief passageway consists of a recess in the end wall of the casing at the outlet end thereof having an outline defined by two lines substantially coincident with portions of the root circle and cylindrical periphery of the thread of said first rotor, a third line substantially coincident with the convex curve of the outline of the thread of said first rotor, and a fourth line substantially coincident with a portion of the cylindrical periphery of the thread of said second rotor, the side of said recess defined by the line substantially coincident with a portion of the cylindrical periphery of said rst rotor being open to said outlet conduit.
13. A rotary screw type fluid pump comprising a pair of intermeshing helically threaded rotors interconnected to drive one rotor from the other at a one-to-one ratio, each of said rotors having a thread which is convex on one side and concave on the opposite side and has an outer peripheral surface of helically cylindrical form, said rotors being so intermeshed that the concave and convex sides of the thread on the first rotor face the concave and convex sides, respectively, of the thread on the second rotor, a casing for said rotors having first and second side wall sections adapted to be connected together in the plane of the rotor axes and cooperating with the rotor threads to form a fluid pumping space and end walls preventing the ingress and egress of fiuid in an axial direction, an inlet conduit connected to said first side wall section, an outlet conduit connected to said second side wall section, a fluid inlet port formed entirely in said first side wall section adjacent one end thereof providing communication between said fluid inlet conduit and the fiuid pumping space defined by the rotor threads and the casing, and a fiuid outlet port formed entirely in said second side wall section adjacent the other end of said casing and providing communication between said uid pumping space and said outlet conduit, each of said inlet and output ports having a shape dened in part by the traces upon the associated side wall section of the peripheral edges of said rotor threads.
14. A rotary screw type uid pump as defined in claim 13 wherein each of said inlet and outlet ports has one edge parallel to and in substantially the same plane as the adjacent end wall of the casing.
15. In a rotary screw type iluid pump of the type comprising a pair of intermeshed helically threaded rotors interconnected to drive one rotor from the other at a one-to-one ratio, each of said rotors having a thread which is convex on one side and concave on the opposite side and has an outer peripheral surface of helically cylindrical form, and a casing for said rotors having a side wall cooperating with the rotor threads to form a uid pumping space and end walls preventing the ingress and egress of uid in an axial direction, a fluid inlet conduit and a fluid outlet conduit connected to said casing and extending in a radial direction with respect to said rotors, and a uid outlet port formed entirely in said side wall adjacent one end of said casing providing direct communication between said outlet conduit and the uid References Cited in the file of this patent UNITED STATES PATENTS 2,111,568 Lysholm et al Mar. 22, 1938 2,174,522 Lysholm Oct. 3, 1939 2,266,820 Smith Dec. 23, 1941 2,287,716 Whitfield June 23, 1942 2,474,653 Boestad June 28, 1949 2,481,527 Nilsson Sept. 13, 1949 2,511,878 Rathman June 20, 1950 2,578,196 Montelius Dec. 11, 1951 2,620,968 Nilsson Dec. 9, 1952 FOREIGN PATENTS 124,376 Sweden Ian. 20, 1949
US346844A 1953-04-06 1953-04-06 Fluid pump or motor of the rotary screw type Expired - Lifetime US2705922A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US346844A US2705922A (en) 1953-04-06 1953-04-06 Fluid pump or motor of the rotary screw type

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US346844A US2705922A (en) 1953-04-06 1953-04-06 Fluid pump or motor of the rotary screw type

Publications (1)

Publication Number Publication Date
US2705922A true US2705922A (en) 1955-04-12

Family

ID=23361269

Family Applications (1)

Application Number Title Priority Date Filing Date
US346844A Expired - Lifetime US2705922A (en) 1953-04-06 1953-04-06 Fluid pump or motor of the rotary screw type

Country Status (1)

Country Link
US (1) US2705922A (en)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3057543A (en) * 1960-02-05 1962-10-09 Ingersoll Rand Co Axial flow compressor
US3057665A (en) * 1960-06-24 1962-10-09 Warren Pumps Inc Pump
US3086474A (en) * 1960-02-18 1963-04-23 Laval Turbine Screw pump
US3146723A (en) * 1959-04-13 1964-09-01 Wildhaber Ernest Screw pump unit
US3622256A (en) * 1969-10-14 1971-11-23 Alexandr Ivanovich Borisoglebs Screw-rotor machine
US3902827A (en) * 1973-07-20 1975-09-02 Svenska Rotor Maskiner Ab Screw compressor
US4210410A (en) * 1977-11-17 1980-07-01 Tokico Ltd. Volumetric type flowmeter having circular and involute tooth shape rotors
US4767284A (en) * 1986-03-20 1988-08-30 Hitachi, Ltd. Screw vacuum pump unit
FR2723766A1 (en) * 1994-08-22 1996-02-23 Kowel Precision Co Ltd SCREW VACUUM PUMP
US6354823B1 (en) * 1998-04-21 2002-03-12 Ateliers Busch Sa Displacement machine having a ceramic rolling bearing
US6368091B1 (en) * 1998-03-25 2002-04-09 Taiko Kikai Industries Co., Ltd. Screw rotor for vacuum pumps
US6375443B1 (en) 1998-03-24 2002-04-23 Taiko Kikai Industries Co., Ltd. Screw rotor type wet vacuum pump
US20030161749A1 (en) * 2002-02-28 2003-08-28 Teijin Seiki Co., Ltd. Vacuum exhausting apparatus
US6719548B1 (en) 2002-10-29 2004-04-13 Imperial Research Llc Twin screw rotor device
US20070258841A1 (en) * 2006-05-08 2007-11-08 Denso Corporation Gas compressor
US20070280846A1 (en) * 2006-06-05 2007-12-06 Denso Corporation Screw compressor
US20080240967A1 (en) * 2005-02-16 2008-10-02 Ateliers Busch Sa Rotary Displacement Machines Having Rotors of Asymmetrical Profile
US20110027118A1 (en) * 2008-04-01 2011-02-03 Zivoslav Milovanovic Device with rotary pistons that can be used as a compressor, a pump, a vacuum pump, a turbine, a motor and as other driving and driven hydraulic-pneumatic machines

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2111568A (en) * 1935-02-12 1938-03-22 Lysholm Alf Rotary compressor
US2174522A (en) * 1935-02-12 1939-10-03 Lysholm Alf Rotary screw apparatus
US2266820A (en) * 1938-07-13 1941-12-23 Frank E Smith Engine
US2287716A (en) * 1941-04-22 1942-06-23 Joseph E Whitfield Fluid device
US2474653A (en) * 1945-04-26 1949-06-28 Jarvis C Marble Helical gear compressor or motor
US2481527A (en) * 1944-06-29 1949-09-13 Jarvis C Marble Rotary multiple helical rotor machine
US2511878A (en) * 1950-06-20 Rathman
US2578196A (en) * 1946-11-30 1951-12-11 Imo Industri Ab Screw compressor
US2620968A (en) * 1945-11-03 1952-12-09 Jarvis C Marble Machine of the screw-compressor type

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2511878A (en) * 1950-06-20 Rathman
US2174522A (en) * 1935-02-12 1939-10-03 Lysholm Alf Rotary screw apparatus
US2111568A (en) * 1935-02-12 1938-03-22 Lysholm Alf Rotary compressor
US2266820A (en) * 1938-07-13 1941-12-23 Frank E Smith Engine
US2287716A (en) * 1941-04-22 1942-06-23 Joseph E Whitfield Fluid device
US2481527A (en) * 1944-06-29 1949-09-13 Jarvis C Marble Rotary multiple helical rotor machine
US2474653A (en) * 1945-04-26 1949-06-28 Jarvis C Marble Helical gear compressor or motor
US2620968A (en) * 1945-11-03 1952-12-09 Jarvis C Marble Machine of the screw-compressor type
US2578196A (en) * 1946-11-30 1951-12-11 Imo Industri Ab Screw compressor

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3146723A (en) * 1959-04-13 1964-09-01 Wildhaber Ernest Screw pump unit
US3057543A (en) * 1960-02-05 1962-10-09 Ingersoll Rand Co Axial flow compressor
US3086474A (en) * 1960-02-18 1963-04-23 Laval Turbine Screw pump
US3057665A (en) * 1960-06-24 1962-10-09 Warren Pumps Inc Pump
US3622256A (en) * 1969-10-14 1971-11-23 Alexandr Ivanovich Borisoglebs Screw-rotor machine
US3902827A (en) * 1973-07-20 1975-09-02 Svenska Rotor Maskiner Ab Screw compressor
US4210410A (en) * 1977-11-17 1980-07-01 Tokico Ltd. Volumetric type flowmeter having circular and involute tooth shape rotors
US4767284A (en) * 1986-03-20 1988-08-30 Hitachi, Ltd. Screw vacuum pump unit
FR2723766A1 (en) * 1994-08-22 1996-02-23 Kowel Precision Co Ltd SCREW VACUUM PUMP
US5667370A (en) * 1994-08-22 1997-09-16 Kowel Precision Co., Ltd. Screw vacuum pump having a decreasing pitch for the screw members
US6375443B1 (en) 1998-03-24 2002-04-23 Taiko Kikai Industries Co., Ltd. Screw rotor type wet vacuum pump
US6368091B1 (en) * 1998-03-25 2002-04-09 Taiko Kikai Industries Co., Ltd. Screw rotor for vacuum pumps
US6354823B1 (en) * 1998-04-21 2002-03-12 Ateliers Busch Sa Displacement machine having a ceramic rolling bearing
US7052259B2 (en) 2002-02-28 2006-05-30 Teijin Seiki Co., Ltd. Vacuum exhausting apparatus
US20030161749A1 (en) * 2002-02-28 2003-08-28 Teijin Seiki Co., Ltd. Vacuum exhausting apparatus
EP1340916A2 (en) * 2002-02-28 2003-09-03 Teijin Seiki Co., Ltd. Screw type vacuum pump
EP1340916A3 (en) * 2002-02-28 2003-11-05 Teijin Seiki Co., Ltd. Screw type vacuum pump
US6719548B1 (en) 2002-10-29 2004-04-13 Imperial Research Llc Twin screw rotor device
US20080240967A1 (en) * 2005-02-16 2008-10-02 Ateliers Busch Sa Rotary Displacement Machines Having Rotors of Asymmetrical Profile
US7625191B2 (en) * 2005-02-16 2009-12-01 Ateliers Busch Sa Rotary displacement machines having rotors of asymmetrical profile
US20070258841A1 (en) * 2006-05-08 2007-11-08 Denso Corporation Gas compressor
US7553144B2 (en) * 2006-05-08 2009-06-30 Denso Corporation Gas compressor having a pair of housing heads
US20070280846A1 (en) * 2006-06-05 2007-12-06 Denso Corporation Screw compressor
US7722345B2 (en) * 2006-06-05 2010-05-25 Denso Corporation Screw compressor
US20110027118A1 (en) * 2008-04-01 2011-02-03 Zivoslav Milovanovic Device with rotary pistons that can be used as a compressor, a pump, a vacuum pump, a turbine, a motor and as other driving and driven hydraulic-pneumatic machines

Similar Documents

Publication Publication Date Title
US2705922A (en) Fluid pump or motor of the rotary screw type
US3314597A (en) Screw compressor
US2243874A (en) Rotary compressor
US2174522A (en) Rotary screw apparatus
US2804260A (en) Engines of screw rotor type
US3151806A (en) Screw type compressor having variable volume and adjustable compression
US2480818A (en) Helical rotary fluid handling device
US2287716A (en) Fluid device
US5667370A (en) Screw vacuum pump having a decreasing pitch for the screw members
US3388854A (en) Thrust balancing in rotary machines
US3848422A (en) Refrigeration plants
US2511878A (en) Rathman
US2578196A (en) Screw compressor
US3073514A (en) Rotary compressors
US2101051A (en) Rotary fluid displacement device
US7008201B2 (en) Gapless screw rotor device
US2486770A (en) Arc generated thread form for helical rotary members
US2101428A (en) Rotary fluid displacement device
US2824687A (en) Rotary compressor
US2656972A (en) Adjustable port arrangement for the high-pressure ends of fluid pumps and motors of the rotary screw type
US4770615A (en) Screw compressor with scavenging port
US3451614A (en) Capacity control means for rotary compressors
US3116871A (en) Rotary gas motor and compressor with conical rotors
US3773444A (en) Screw rotor machine and rotors therefor
US3180559A (en) Mechanical vacuum pump