GB1569144A

GB1569144A - Rotary positive displacement fluid machine

Info

Publication number: GB1569144A
Application number: GB4410776A
Authority: GB
Original assignee: Inst Cercetare Si Proiectare T
Current assignee: Inst Cercetare Si Proiectare T
Priority date: 1976-10-23
Filing date: 1976-10-23
Publication date: 1980-06-11

Description

(54) ROTARY POSITIVE DISPLACEMENT FLUID MACHINE (71) We, INSTITUTUI DE CERCETARI Sl PROIEC rARI TEHNOLOGICE PENTRU IN DUSTRIA CONSTRUCTIlLOR DE MASINI, a State Enterprise organised and existing under the laws of Romania, of 105 Sos, Oltenitei, Bucharest, Romania, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a rotary positive displacement fluid machine.

Such a machine is defined as a rotary machine either for converting the energy held by a fluid into mechanical energy or vice versa and which functions essentially from changes of the volume occupied by the fluid within the machine.

According to the invention there is provided a rotary positive displacement fluid machine as hereinbefore defined, comprising a fixed cylindrical casing, at least one partition wall on the circumferential internal surface of the casing extending parallel to the axis of the casing, side discs and a rotor mounted therebetween for rotation in the casing about the axis thereof, the side discs being in sealing relationship with the fixed cylindrical casing, with adjacent end surfaces of the rotor and with the or each partition wall, the rotor having extending between its end surfaces an outer surface which is cylindrical and coaxial with the internal surface of the casing, there being at least one part-cylindrical recess in the said outer surface, the cylindrical outer surface of the rotor being in sealing relationship with the or each partition wall during a part of each revolution of the rotor, a roller mounted for rotation in the or each recess about an orbital axis parallel with the axis of the casing with the end faces of the roller in sealing relation- ship with the side discs, the outer surface of the or each roller being cylindrical and having its axis coincident with the respective orbital axis and also having a groove therein extending parallel with such orbital axis for co-operation with the or each partition wall, the cylindrical outer surface of the or each roller being in sealing relationship with both the internal surface of the casing and the recess it occupies in the rotor during at least a part of each revolution of the rotor, and the groove in the or each roller being in sealing relationship with the or each partition wall during a part of each revolution of the rotor, gearing for so relating the rotation of the rotor about the axis of the casing to the rotation of the or each roller about its orbital axis that the groove in the or each roller is positioned to receive the or each partition wall each time the roller passes the partition wall, the or each roller, the or each partition wall, the internal surface of the casing, the cylindrical outer surface of the rotor and the side discs defining, as the rotor rotates, a chamber behind the or each roller which is increasing in volume and a chamber ahead of the or each roller which is decreasing in volume, ports for entry of fluid into and exist of fleld from the chambers respectively increasing and decreasing in volume, and valve means for opening and closing at least one of the ports.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic cross-section of a rotary positive displacement fluid machine as hereinbefore defined; Fig. 2 is a cross-section of a rotary positive displacement fluid machine as hereinbefore defined which acts as a fluid motor; Fig. 3 is a cross-section of a rotary positive displacement fluid machine as hereinbefore defined in the form of an internal combustion engine; Fig. 4 is a fragmentary axial section of a multiple unit internal combustion engine comprising a plurality of units each as shown in Fig. 3; Fig.S represents schematically a unit in either of Figs. 6 and 7; Fig. 6 represents schematically a multistage compressor; Fig. 7 represents schematically a similar multi-stage compressor to that shown in Fig. 6 but also including a turbine; Figs. 8, 9 and 10 are views of a seal; Fig. 11 shows the placement of hardened surface positions for continually grinding the seals such as shown in Figs. 8, 9 and 10 during operation of the machine; Fig. 12 is a schematic cross-section of a rotary positive displacement fluid motor as hereinbefore defined in the form of a fluid motor which can be selectively operated in opposite directions; and Fig. 13 is a partially schematic axial section of a multiple unit fluid motor comprising a plurality of units each as shown in Fig. 12.

In a first embodiment of the invention as shown in Fig. 1, a fixed cylindrical casing 2 having on its internal surface three partition walls 4 extending parallel to the axis b of the casing and spaced equally apart circumferentially. A rotor 3 is mounted fast to and between side discs (such as discs 11 in Fig. 4) for rotation in the casing about the axis b and its outer surface is cylindrical about the axis b except for two diametrically opposite part-cylindrical recesses. In each of these recesses a roller 1 is mounted for rotation about an axis a.

Each roller 1 has a groove c extending parallel to the axis a for co-operation with the partition walls 4.

The rollers 1 are positively driven from the rotor 3 by planetary gearing (not shown) so as to orbit around the axis b and rotate about their respective axes a in such a manner that the partition walls 4 enter the grooves c and thus permit the rotor 3 to rotate about the axis b. In so doing, each working space defined between the internal surface of the casing 2 and the rotor 3 and between two partition walls 4 is in turn traversed by each roller 1 so as to divide the working space into a chamber with a reducing volume ahead of the roller and a chamber with an increasing volume behind the roller.

Assuming that the rotor 3 is driven in an anti-clockwise direction, as each roller 1 begins to leave one of the partition walls 4 the increasing volume of the chamber behind the roller draws fluid in through a port d and the reducing volume of the chamber ahead of the roller expels fluid through a valved port 5. The machine then acts as a pump or compressor.

Assuming that fluid is admitted under pressure in turn through each valved port 5, the pressure acts on each roller 1 in the direction shown by the arrows and produces a force e producing a torque driving the rotor 3 in the clockwise direction, the fluid being expelled through the ports d.

The machine then acts as a motor.

In a second embodiment of the invention shown in Fig. 2, there are two partition walls 4 and the rollers 1 are larger in diameter than in Fig. 1. This embodiment acts as a motor, fluid under pressure being admitted through ports f in the rotor 3, and valved openings 6 and ducts in the rollers 1. Further fluid under pressure may be admitted through the valved ports 8 in the casing 2 to increase the power rating of the motor by an amount depending on the degree to which the valved ports 8 are opened.

The diameter of each roller 1 is virtually equal to the radius of the interior surface of the casing 2 so that any point on the cylindrical surface of each roller has a hypocycloid locus which is a straight line lying on a diameter of the interior surface of the casing 2. Because of this the sides of the partitional walls 4 can be made planar and lie on planes disposed radially of the interior surface of the casing 2 and the edges of the grooves c can be easily sealed as at 7 with the walls 4.

In a third embodiment as shown in Fig.

3 there is but a single roller 1 which like each roller 1 in Fig. 2 has a diameter virtually equal to the radius of the interior surface of the casing 2. Thus, the form of the partition walls 4 is similar to the form of the walls 4 in Fig. 2 with the consequent ease of sealing. This embodiment is in the form of an internal combustion engine and a combustion chamber j fitted with a spark plug is interposed between transfer ports on opposite sides of one of the partition walls 4. One of the transfer ports between the combustion chamber j and the working space k is controlled by a valve 9 and the other transfer port between the combustion chamber 7 and the working space I is controlled by a valve 10. The valve 9 is in the form of a rotary cock driven by an intermittent rotation maltese cross mechanism. The valve 10 is in the form of a poppet valve but can be similar in form to the valve 9. On opposite sides of the partition wall 4 remote from the combustion chamber j is an entry port g and an exit port It. Seals are shown at 7.

With the rotor 3 rotating anti-clockwise as shown by the arrow, the roller 1 traverses the working space 1 and in so doing the chamber behind the roller increases in volume so as to draw in a new charge of a combustible mixture and the chamber ahead of the roller reduces in volume to compress a previous charge in the combustion chamber i past the opened valve 10, the valve 9 being closed. As the roller I approaches the valve 10 this valve is closed to retain the compressed charge in the combustion chamber j. A groove m in the partition wall 4 at the combustion chamber i serves to vent any entrapped charge as this partition wall enters the groove in the roller 1.As the roller 1 starts to travcrse the working space k the valve 9 is opened and the compressed charge is exploded by the spark plug and the rapidly cxpanding exploded charge expands out of the combustion chamber j into the chamber behind the roller 1 so as to apply torque to the rotor 3. At the same time the previous spent charge is exhausted from the chamber ahead of the roller 1 through the port h. After the partition wall 4 remote from the combustion chamber j enters and leaves the groove in the roller 1 a new cycle starts with the valve 9 closed and the valve 10 opened.

Fig. 4 shows the engine of Fig. 3 in axial section as a unit of a multiple unit engine, each end of the rotor 3 having a disc 11 secured thereto and closing-off the working spaces k and 1. Annular seals 12 in the discs 11 are maintained in rubbing contact with end surfaces of the casing 2 by springs 13. Smaller annular seals 14 in the discs 11 are also maintained in rubbing contact with the ends of the roller 1 by springs and the roller I is also pressed into rolling con tect with the interior surface of the casing 2 by a spring 15 in the bearing of the roller.

A ring gear 16 is fixed in an end cover 17 and meshes with a planetary pinion 18 on an axle of the roller 1. Fig. 4 also shows a further roller 19 mounted coaxially with the roller 1 and a further rotor 20 mounted coaxially with the rotor 3 in a multiple unit engine.

Fig. S represents schematically a single unit such as shown in Fig. 3 but can also be regarded as representing either of the single units shown in Figs. 1 and 2. Fig.

6 shows schematically a multi-stage compressor wherein three units each as represented in Fig. 5 are arranged on each of two common shafts 21. The outer units on each axis are now pressure stages 22 and the intermediate unit is a high -pressure stage 23. Each low pressure stage 22 draws in fluid and delivers it under pressure to the high pressure stage 23 which in turn delivers the fluid at a higher pressure. The shafts 21 carry gears 24 driven by a central gear on a main shaft 25. Fig. 7 shows schematically a similar system to that shown in Fig. 6 but wherein the fluid delivered from the high pressure stage 23 drives a turbine 26 from which fluid is delivered to extra stages 27.

The seals shown at 7 in Fig. 3 each comprises a pair of strips 28, 29 shown in Figs.

8, 9 and 10. Fig. 9 shows the strips 28, 29 7 in a slot in the partition wall 4 and in engagement with the rotor 3 and the discs 11.

The strips 28, 29 are urged towards the rotor 3 and the discs 11 by springs 30, 31 respectively but are prevented from leaving the slot in the partition wall 4 by mem- bers 32 set into the walls of the slot and losely engaging in recesses in the strips 28, 29.

In Fig. 11 there are shown on the rotor 3 a convex surface portion n and a concave surface portion o both of increased hardness. There are also shown on the disc 11 flat surface portions 33 and 34 of increased hardness. The strips 28, 29 in the partition walls 4 are continually ground by the surface portions n, 33 and the strips 28, 29 in the roller 1 are continually ground by the surface portions o, 34. The clearance between the roller 1 and the surface portion o decreases from both ends of the arcuate extent thereof towards the middle so as to achieve a smooth entrainment of the strips 28, 29 in the roller 1 against the surface portion o with maximum friction occurring at the middle of its arcuate extent.

In Fig. 12 there is shown schematically a motor which can be driven selectively in opposite directions. For driving the motor in an anticlockwise direction as shown in Fig. 12 fluid is fed under pressure into line 35 and line 36 is closed-off. The effect of this is to pressurise the right hand side of the fixed arcuate valve housing to move the valve member 37 therein in an anticlockwise direction and open tbe exit port d on the right hand side of the partition wall 4 for outflow of fluid through the line 38 while closing the exit port on the left hand side of the wall 4.Pressurised fluid from line 35 is fed into fixed entry port s and while a port p in disc 11 is passing over the fixed entry port s the pressurised fluid enters the chamber behind the roller 1 and between the roller and the partition wall 4 to increase the volume of the chamber and produce a torque driving the rotor 3 in an anti-clockwise direction. Consequently, the chamber ahead of the roller 1 and between the roller and the partition wall 4 decreases in volume and outflow occurs through the open exit port d and the line 38.

Conversely, for driving the motor in a clockwise direction as shown in Fig. 12 fluid is fed under pressure into line 36 and line 35 is closed-off. The effect of this is to pressurise the left hand side of the fixed arcuate valve housing to move the valve member 37 therein in a clockwise direction and open the exit port d on the left hand side of the partition wall 4 for outflow of fluid through the line 38 while closing the exit port on the right hand side of the wall 4. In operation, fixed entry port t takes the place of fixed entry port s and a port r takes the place of the port p. The fixed entry ports s and t may be effectively extended by fixed ports U. These are of advantage in starting the motor in any position and in increasing the torque at low rotational speeds.

As shown in Fig. 13, the motor shown in Fig. 12 can form one unit of a three unit motor in which the three rollers 1 are on a common orbiting axis and driven by a planetary gear 18 meshing with a ring gear 16. Although, for ease of illustration, the respective fixed arcuate valve housings and the valve members 37 therein are shown at the same position, it will be understood that these items together with the partition walls 4 and the exhaust ports d are disposed at 1200 intervals and that the grooves in the rollers 1 are similarly staggered so that the cycles of operation of the units are 1200 out of phase with each other so as to smooth out the torque output and permit easier starting of the motor.

WHAT WE CLAIM IS:- 1. A rotary positive displacement fluid machine as hereinbefore defined, comprising a fixed cylindrical casing, at least one partition wall on the circumferential internal surface of the casing extending parallel to the axis of the casing, side discs and a rotor mounted therebetween for rotation in the casing about the axis thereof, the side discs being in sealing relationship with the fixed cylindrical casing, with adjacent end surfaces of the rotor and with the or each partition wall, the rotor having extending between its end surfaces an outer surface which is cylindrical and coaxial with the internal surface of the casing, there being at least one Dart-cylindrical recess in the said outer surface, the cylindrical outer surface of the rotor being in sealing relationship with the or each partition wall during a part of each revolution of the rotor, a roller mounted for rotation in the or each recess about an orbital axis parallel with the axis of the casing with the end faces of the roller in sealing relationship with the side discs, the outer surface of the or each roller being cylindrical and having its axis coincident with the respective orbital axis and also having a groove therein extending parallel with such orbital axis for co-operation with the or each partition wall, the cylindrical outer surface of the or each roller being in sealing relationship with both the internal surface of the casing and the recess it occupies in the rotor during at least a part of each revolution of the rotor, and the groove in the or each roller being in sealing relationship with the or each partition wall during a part of each revolution of the rotor, gearing for so relating the rotation of the rotor about the axis of the casing to the rotation of the or each roller about its orbital axis that the groove in the or each roller is positioned to receive the or each partition wall each time the roller passes the partition wall, the or each roller, the or each partition wall, the internal surface of the casing, the cylindrical outer surface of the rotor and the side discs defining, as the rotor rotates, a chamber behind the or each roller which in increasing in volume and a chamber ahead of the or each roller which is decreasing in volume, ports for entry of fluid into and exit of fluid from the chambers respectively increasing and decreasing in volume, and valve means for opening and closing at least one of the ports.

2. A machine according to claim 1, wherein the fluid entry and exit ports are provided in the fixed cylindrical casing.

3. A machine according to claim 1 or 2, wherein a fluid transfer duct is provided in the or each roller for transferring fluid between the interior of the rotor and one of the chambers.

4. A machine according to claim 2, in the form of an internal combustion engine, wherein the fluid entry and exit ports are transfer ports provided in the fixed cylindrical casing on opposite sides of a first partition wall and two further fluid entry and exit ports are also provided on opposite sides of a second partition wall and a single roller is provided, the transfer ports being controlled by the valve means and being interconnected by a combustion chamber for receiving via one transfer port a charge of explosive fluid compressed by the roller moving towards the first partition wall and for transferring via the other transfer port the charge exploded in the combustion chamber to the chamber behind the roller passing the first partition wall and moving away therefrom.

5. A machine according to claim 1, in the form of a fluid motor, wherein there is a single partition wall and a single roller, a fluid exit port is provided in the fixed cylindrical casing on each side of the partition wall, the said valve means comprises a fluid port provided on each side of the roller in a side disc rotatable with the rotor, a fixed valve housing has a valve member therein, and a fixed fluid entry port is provided on each side of the partition wall for traversing by respective ones of the fluid ports in the side disc, and two lines are provided through which pressurised fluid can be fed selectively either to supply pressurised fluid to the fixed fluid entry duct on one side of the partition wall and to move the valve member to one end position to close the fluid exit port on the one side

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 4. In operation, fixed entry port t takes the place of fixed entry port s and a port r takes the place of the port p. The fixed entry ports s and t may be effectively extended by fixed ports U. These are of advantage in starting the motor in any position and in increasing the torque at low rotational speeds. As shown in Fig. 13, the motor shown in Fig. 12 can form one unit of a three unit motor in which the three rollers 1 are on a common orbiting axis and driven by a planetary gear 18 meshing with a ring gear 16. Although, for ease of illustration, the respective fixed arcuate valve housings and the valve members 37 therein are shown at the same position, it will be understood that these items together with the partition walls 4 and the exhaust ports d are disposed at 1200 intervals and that the grooves in the rollers 1 are similarly staggered so that the cycles of operation of the units are 1200 out of phase with each other so as to smooth out the torque output and permit easier starting of the motor. WHAT WE CLAIM IS:-

1. A rotary positive displacement fluid machine as hereinbefore defined, comprising a fixed cylindrical casing, at least one partition wall on the circumferential internal surface of the casing extending parallel to the axis of the casing, side discs and a rotor mounted therebetween for rotation in the casing about the axis thereof, the side discs being in sealing relationship with the fixed cylindrical casing, with adjacent end surfaces of the rotor and with the or each partition wall, the rotor having extending between its end surfaces an outer surface which is cylindrical and coaxial with the internal surface of the casing, there being at least one Dart-cylindrical recess in the said outer surface, the cylindrical outer surface of the rotor being in sealing relationship with the or each partition wall during a part of each revolution of the rotor, a roller mounted for rotation in the or each recess about an orbital axis parallel with the axis of the casing with the end faces of the roller in sealing relationship with the side discs, the outer surface of the or each roller being cylindrical and having its axis coincident with the respective orbital axis and also having a groove therein extending parallel with such orbital axis for co-operation with the or each partition wall, the cylindrical outer surface of the or each roller being in sealing relationship with both the internal surface of the casing and the recess it occupies in the rotor during at least a part of each revolution of the rotor, and the groove in the or each roller being in sealing relationship with the or each partition wall during a part of each revolution of the rotor, gearing for so relating the rotation of the rotor about the axis of the casing to the rotation of the or each roller about its orbital axis that the groove in the or each roller is positioned to receive the or each partition wall each time the roller passes the partition wall, the or each roller, the or each partition wall, the internal surface of the casing, the cylindrical outer surface of the rotor and the side discs defining, as the rotor rotates, a chamber behind the or each roller which in increasing in volume and a chamber ahead of the or each roller which is decreasing in volume, ports for entry of fluid into and exit of fluid from the chambers respectively increasing and decreasing in volume, and valve means for opening and closing at least one of the ports.

of the partition wall and open the fluid exit port on the other side of the partition wall and drive the rotor in one direction or to supply pressurised to the fixed fluid entry duct on the other side of the partition wall and to move the valve member to the other end position to close the fluid exit port on the other side of the partition wall and open the fluid exit port on the one side of the partition wall and drive the rotor in the opposite direction.

6. A machine according to any preceding claim, wherein the or each partition wall and the or each roller have slots therein accommodating seals, each seal comprising a pair of strips urged by springs towards the surfaces with which the partition wall and roller are in sealing relationship but prevented from leaving the slot by members set in the walls of the slot and loosely engaging the strip.

7. A machine according to claim 6, wherein the surfaces with which the or each partition wall and the or each roller are in sealing relationship have surface portions of increased hardness for continually grinding the sealing edges of the strips during operation of the machine.

8. A multiple unit machine comprising a plurality of units each being a machine according to any preceding claim and wherein the rotors are rotatable about a common axis, the rollers are rotatable about one or more common orbital axes, and the partition walls are staggered so that the cycles of operation of the units are phased with respect to each other.

9. A multiple unit machine in the form of a multi-stage compressor comprising a plurality of units each being a machine according to claim 1 and each forming a fluid compression stage with a fluid outlet of one stage connected with a fluid inlet of the or another stage.

10. A rotary positive displacement fluid machine as hereinbefore defined substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

11. A rotary positive displacement fluid machine as hereinbefore defined in the form of a fluid motor and substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

12. A rotary positive displacement fluid machine as hereinbefore defined in the form of an internal combustion engine and substantially as hereinbefore described with reference to Fig. 3 of the accompanying drawings.

13. A multiple unit internal combustion engine comprising a plurality of units each being a machine according to claim 12 and substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.

14. A multi-stage compressor substantially as hereinbefore described with reference to Fig. 6 of the accompanying drawings.

15. A multi-stage compressor substantially as hereinbefore described with reference to Fig. 7 of the accompanying drawings.

16. A rotary positive displacement fluid machine as hereinbefore defined in the form of a fluid motor and substantially as hereinbefore described with reference to Fig. 12 of the accompanying drawings.

17. A multiple unit fluid motor comprising a plurality of units each being a machine according to claim 16 and substantially as hereinbefore described with reference to Fig. 13 of the accompanying drawings.

18. A rotary positive displacement fluid machine as hereinbefore defined according to any one of claims 10 to 17 comprising seals substantially as hereinbefore described with reference to Figs. 8, 9 and 10 of the accompanying drawings.

19. A machine according to claim 18, comprising hardened surface portions for continually grinding the seals during operation of the machine, substantially as hereinbefore described with reference to Fig.

11 of the accompanying drawings.