US20050191173A1

US20050191173A1 - Rotary ram-in compressor

Info

Publication number: US20050191173A1
Application number: US11/093,138
Authority: US
Inventors: Essam Awdalla
Original assignee: Individual
Current assignee: RRC-SGTE TECHNOLOGIES LLC
Priority date: 2003-09-23
Filing date: 2005-03-29
Publication date: 2005-09-01

Abstract

A rotary ram-in compressor, used for pressurizing a gas into a container, comprising: a stationary casing having at least one inlet passage, and a receiver; at least one conduit for communicating the receiver with the container; a drive shaft supported for rotation in a given direction inside the casing; and a rotor assembly housed inside the casing and including at least one rotary ram-in compressor stage. In operation, gas is rammed through the feeding channels of the rotary ram-in compressor to the compressor's receiver, from which it flows through the conduit to the container, wherein it collects. In preferred embodiments, valve means for controlling the flow of gas through the conduit, and a pressure sensor(s) for detecting the degree of rise in the pressure of gas supplied by the rotary ram-in compressor, are also provided.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This non-provisional utility patent application claims the benefit of two prior filed co-pending non-provisional applications; the present application is a continuation-in-part of U.S. patent application Ser. No. 10/669,514, filed Sep. 23, 2003, and U.S. patent application Ser. No. 11/070914, filed Mar. 3, 2005, which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a positive displacement compressor and, more particularly, to a rotary positive displacement compressor used for increasing the density and pressure level of a gas within a container.

BACKGROUND OF THE INVENTION

Rotary positive displacement compressors are well known devices, used in several fields to increase the density and pressure level of a gas within a container. The main components of a conventional rotary positive displacement compressor are a casing; and a rotating element mounted within the casing, with contact sealing means usually provided between the opposing surfaces of the casing and the rotating element, which limits their maximum allowable operating rotational speeds, and hence their maximum provided mass flow rates, due to the developed friction between the rubbing parts within them.
In some applications, e.g. pressurizing natural gas within tanks for use by different types of land vehicles and the like, it is desirable to have a rotary positive displacement compressor having no rubbing parts within, to allow operating it at relatively high rotational speeds, and thus providing high mass flow rate of gas within it, to minimize the time needed for charging a given tank with pressurized gas.
Thus, there is a need for a rotary positive displacement compressor having no rubbing parts within, which allows its use in the applications wherein relatively high mass flow rates are needed.

SUMMARY OF THE INVENTION

The present invention provides a rotary positive displacement compressor having no rubbing parts within, which allows its use in the applications wherein relatively high mass flow rates are needed.
Accordingly, the present invention provides a rotary ram-in compressor, used for pressurizing a gas into a container, having a plurality of feeding channels, moving at high speed, through which the gas to be pressurized is rammed, followed by positive displacement of the rammed in gas to a receiver, from which it flows to the container.
In a preferred embodiment, the rotary ram-in compressor, used for pressurizing a gas into a container, comprises a stationary casing having at least one inlet passage, for admission of the gas, and a receiver; at least one conduit for communicating the said receiver with the said container wherein the pressurized gas collects; a drive shaft supported for rotation in a given direction inside the casing by an arrangement of bearings, and extending to a drive receiving end located outside the casing; and a rotor assembly housed inside the casing and including a first disk secured for rotation with the drive shaft and lying in a first plane transverse to the rotational axis of the drive shaft; a second disk lying in a second plane transverse to the rotational axis of the drive shaft, with the inner surfaces of the two disks defining an annular space in-between; and a plurality of vanes arranged circumferentially within said annular space, each vane attached to both disks defining the annular space, each vane has a leading edge, a trailing edge, a concave surface and a convex surface, with the average angles of inclination of the successive portions of the vane with respect to a plane comprising the midpoint of the vane and perpendicular to a radial plane including the rotational axis of the rotor and the midpoint of the vane decreases preferably gradually from its leading edge towards its trailing edge, within a range from about +18 to about −18 degrees, the opposing parts of the surfaces of each two adjacent vanes along with the opposing parts of the two disks' surfaces confined between the opposing parts of the surfaces of each two adjacent vanes defining a feeding channel between them, each feeding channel has an inlet communicating with the compressor's inlet passage(s) and an outlet communicating with the compressor's receiver.
In a preferred embodiment of the rotary ram in compressor of the present invention, each two opposing surfaces, of those defining each of the feeding channels between them, are parallel to one another, with the cross-sectional area of the inlet of each of the channels being equal to the cross sectional area of its outlet.
In another preferred embodiment, in order to increase the level of pressure rise provided by the rotary ram-in compressor of the present invention, each of the feeding channels is slightly converging from its inlet towards its outlet. The convergence of the feeding channel is provided by designing the boundaries confining the channel between them so that the axial width of the channel and/or the width between the opposing parts of the surfaces of the two adjacent vanes confining the channel between them decrease preferably gradually from the inlet of the channel towards its outlet, and hence, the cross-sectional area of the channel decreases preferably gradually from its inlet towards its outlet.
The gradual decrease in the axial width of the feeding channel is provided by designing the part(s) of the surface(s) of one (or both) of the disks related to the channel and confined between the opposing parts of the surfaces of the two adjacent vanes so that it is sloping preferably gradually from the inlet of the channel towards its outlet. The gradual decrease in the width between the opposing parts of the surfaces of the two adjacent vanes is provided by designing the vanes with suitable angles of inclination at their different parts, according to the desired rate of convergence of the channel.
In operation, gas is rammed through the feeding channels of the compressor, which displace it in a generally radially inward direction (when a radial in-flowing rotary ram-in compressor is used), or in a generally radially outward direction (when a radial out-flowing rotary ram-in compressor is used), to the compressor's receiver. The rammed in gas is first compressed by both the pressurized gas collecting within the compressor's receiver and by the reaction force developed on the free parts of the surfaces of the vanes next to the outlets of the feeding channels, followed by displacing the pressurized freshly introduced gas to the receiver, by the free parts of the surfaces of the vanes. Then, the pressurized gas flows through the conduit to the container, wherein it collects, due to the pressure gradient between the compressor's receiver and the container. As used herein, the free part of the surface of a vane refers to the part of the surface of the vane that is not opposed by any part of the surfaces of its adjacent vanes.
In a preferred embodiment, the conduit used for communicating the compressor's receiver with the container is provided with valve means for controlling the flow of gas through it. Once a predetermined pressure level is reached within the compressor's receiver (to be determined experimentally for each design), the driving means used to drive the compressor's rotor is turned off, and the valve means controlling the flow of gas through the conduit communicating the compressor's receiver with the container is closed, to prevent raising the pressure level within the compressor above the allowed design levels. In a preferred embodiment, turning off the driving means and closing the valve means are done manually. In another preferred embodiment, at least one pressure sensor is used for detecting the degree of rise in the pressure of gas supplied by the rotary ram-in compressor, either within the compressor's receiver or within the said conduit, and when a predetermined pressure level is reached, the sensor sends correlative signals to turn off the driving means and to close the valve means.
In another preferred embodiment, the rotary ram-in compressor, used for pressurizing a gas into a container, comprises a stationary casing having at least one inlet passage, for admission of the gas, and a receiver; at least one conduit for communicating the said receiver with the said container wherein the pressurized gas collects; a drive shaft supported for rotation in a given direction inside the casing by an arrangement of bearings, and extending to a drive receiving end located outside the casing; and a rotor assembly housed inside the casing. The rotor assembly is functionally divided into at least two successive rotary ram-in compressor stages, with each of the rotary ram-in compressor stages including a first disk secured for rotation with the drive shaft and lying in a first plane transverse to the rotational axis of the drive shaft; a second disk lying in a second plane transverse to the rotational axis of the drive shaft, with the inner surfaces of the two disks defining an annular space in-between; and a plurality of vanes arranged circumferentially within said annular space, each vane attached to both disks defining the annular space, each vane has a leading edge, a trailing edge, a concave surface and a convex surface, with the average angles of inclination of the successive portions of the vane with respect to a plane comprising the midpoint of the vane and perpendicular to a radial plane including the rotational axis of the rotor and the midpoint of the vane decreases preferably gradually from its leading edge towards its trailing edge, within a range from about +18 to about −18 degrees, the opposing parts of the surfaces of each two adjacent vanes along with the opposing parts of the two disks' surfaces confined between the opposing parts of the surfaces of each two adjacent vanes defining a feeding channel between them, each feeding channel has an inlet and an outlet, with the inlets of the feeding channels of the first rotary ram-in compressor stage communicating with the compressor's inlet passage(s) and with the outlets of the feeding channels of the last rotary ram-in compressor stage communicating with the compressor's receiver.
In operation, when the rotor assembly is functionally divided into two successive rotary ram-in compressor stages, the gas is rammed through the feeding channels of the first rotary ram-in compressor stage, which displace it in a generally radially inward direction (when a radial in-flowing rotary ram-in compressor is used), or in a generally radially outward direction (when a radial out-flowing rotary ram-in compressor is used), to the inlets of the feeding channels of the second rotary ram-in compressor stage, through which it is rammed to the compressor's receiver, from which it flows through the conduit to the container, wherein it collects. When the rotor assembly is functionally divided into more than two successive rotary ram-in compressor stages, the gas is rammed through the feeding channels of the first rotary ram-in compressor stage, which displace it in a generally radially inward direction (when a radial in-flowing rotary ram-in compressor is used), or in a generally radially outward direction (when a radial out-flowing rotary ram-in compressor is used), followed by further ramming of the gas through the feeding channels of the successive intermediate rotary ram-in compressor stage(s), till it is rammed through the feeding channels of the last rotary ram-in compressor stage to the compressor's receiver, from which it flows through the conduit to the container, wherein it collects.
In a preferred embodiment, the conduit used for communicating the compressor's receiver with the container wherein the pressurized gas collects is provided with valve means for controlling the flow of gas through it. Once a predetermined pressure level is reached within the compressor's receiver (to be determined experimentally for each design), the driving means used to drive the compressor's rotor is turned off, and the valve means controlling the flow of gas through the conduit communicating the compressor's receiver with the container is closed, to prevent raising the pressure level within the compressor as described herein before.

BREIF DESCRIPTION OF THE DRAWINGS

The description of the objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of the exemplary embodiments in accordance with the accompanying drawings, wherein:
FIG. 1 is a sectional view in a schematic representation of an exemplary embodiment of a rotary ram-in compressor, used for pressurizing a gas into a container, in accordance with the present invention.
FIG. 2 is a cross sectional view, taken at the plane of line 2-2 in FIG. 1.
FIG. 3 is a cross sectional view, taken at the plane of line 3-3 in FIG. 1.
FIG. 4 is a sectional view in a schematic representation of another exemplary embodiment of a rotary ram-in compressor, used for pressurizing a gas into a container, in accordance with the present invention.
FIGS. 5-10 are schematic representations of alternatives in which the feeding channels confined between the opposing parts of the surfaces of the adjacent vanes of a rotary ram-in compressor in accordance with the present invention, may be designed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Prior filed U.S. patent application Ser. Nos. 10/669,514 and 11/070,914 provide rotary ram-in compressors having a plurality of vanes attached to discs, with the opposing parts of each two adjacent vanes defining a feeding channel in-between. In operation, working gases are rammed through the feeding channels, followed by positive displacement of the rammed-in gases to a receiver wherein pressurized gases collect. The pressurized gases are actively swept from the receiver by either a successive rotary ram-in compressor or a successive rotary ram compressor (disclosed in the inventor's earlier International Patent Application Serial number: PCT/US00/17044, entitled “Rotary ram fluid pressurizing machine”), which enables providing a flowing stream of pressurized gases, and thus making them convenient for use in gas turbine engines, and the like. However, this arrangement makes them inconvenient for use in the applications wherein increasing the density and pressure level of a gas within a container is needed. The present application clearly defines a rotary ram-in compressor, wherein the pressurized gas provided by the compressor collects within a container.
FIG. 1 is a sectional view in a schematic representation of an exemplary embodiment of a rotary ram-in compressor, used for pressurizing a gas into a container, in accordance with the present invention.
The main components of the rotary ram-in compressor in this embodiment are a stationary casing (21) having an inlet passage (22) for admission of the gas to be pressurized (23), and a receiver (24) wherein pressurized gases (25) collect; a conduit (26) for communicating the receiver (24) with the said container (not shown in the drawing for simplicity), wherein the pressurized gas (25) collects; a drive shaft (27) supported for rotation in a given direction inside the casing by an arrangement of bearings (28), and extending to a drive receiving end located outside the casing; and a rotor assembly housed inside the casing and secured for rotation with the drive shaft (27). The rotor assembly is functionally divided into four successive rotary ram-in compressor stages (29,30,31,32), the first two rotary ram-in compressor stages (29,30) include a disk (33) secured for rotation with the drive shaft (27) and lying in planes transverse to the rotational axis of the drive shaft; two disks (34,35) having large open centers and widened rims, and lying in planes transverse to the rotational axis of the drive shaft, with the opposing surfaces of each two adjacent disks defining an annular space in-between; and plurality of vanes (36,37) arranged circumferentially within said annular spaces, each vane attached to both disks defining the annular space. The last two rotary ram-in compressor stages (31,32) include a disk (38) secured for rotation with the drive shaft (27) and lying in planes transverse to the rotational axis of the drive shaft; two disks (39,40) having large open centers and widened rims, and lying in planes transverse to the rotational axis of the drive shaft, with the opposing surfaces of each two adjacent disks defining an annular space in-between; and plurality of vanes (41,42) arranged circumferentially within said annular spaces, each vane attached to both disks defining the annular space. As shown in FIG. 2 which is a cross sectional view, taken at the plane of line 2-2 in FIG. 1, each vane (36) has a leading edge (43), a trailing edge (44), a concave surface (45) and a convex surface (46), with the average angles of inclination of the successive portions of the vane with respect to a plane comprising the midpoint of the vane and perpendicular to a radial plane including the rotational axis of the rotor and the midpoint of the vane decreases preferably gradually from its leading edge towards its trailing edge, within a range from about +2 to about −18 degrees, the opposing parts of the surfaces of each two adjacent vanes along with the opposing parts of the two disks' surfaces confined between the opposing parts of the surfaces of each two adjacent vanes defining a feeding channel (47) between them, each feeding channel (47) having an inlet (48) communicating with the inlet passage of the compressor (22), and an outlet (49) communicating with the space relatively radially outward of the vanes (50), which forms the receiver of the first rotary ram-in compressor stage and the inlet passage of the second rotary ram-in compressor stage.
As also shown in FIG. 3 which is a cross sectional view, taken at the plane of line 3-3 in FIG. 1, each of the vanes (37) of the second rotary ram-in compressor stage (30) has a leading edge (51), a trailing edge (52), a concave surface (53) and a convex surface (54), with the average angles of inclination of the successive portions of the vane with respect to a plane comprising the midpoint of the vane and perpendicular to a radial plane including the rotational axis of the rotor and the midpoint of the vane decreases preferably gradually from its leading edge towards its trailing edge, within a range from about +18 to about −2 degrees, the opposing parts of the surfaces of each two adjacent vanes along with the opposing parts of the two disks' surfaces confined between the opposing parts of the surfaces of each two adjacent vanes defining a feeding channel (55) between them, each feeding channel (55) having an inlet (56) communicating with the inlet passage of the compressor stage (50), and an outlet (57) communicating with the space relatively radially inward of the vanes (58), which forms the receiver of the second rotary ram-in compressor stage and the inlet passage of the third rotary ram-in compressor stage.
In operation, gas is rammed through the feeding channels (47) of the first rotary ram-in compressor stage (29), which displace it in a generally radially outward direction, followed by further ramming of the gas through the feeding channels of the two successive intermediate rotary ram-in compressor stages (30,31), till it is rammed through the feeding channels of the last rotary ram-in compressor stage (32) to the compressor's receiver (24), from which it flows through the conduit (26) to the container, wherein it collects.
The embodiment also includes a valve (59) for controlling the flow of gas through the conduit (26) communicating the receiver (24) with the container, and a pressure sensor (60) for detecting the degree of rise in the pressure of gas within the compressor's receiver (24). Once a predetermined pressure level is reached within the compressor's receiver (24), the pressure sensor (60) sends correlative signals to a linear step motor (61) to close the valve (59), and to turn off the driving means used for driving the compressor's rotor (not shown in the drawing for simplicity).
The outer surface of the casing is provided with a plurality of circumferential ribs (62) for cooling the pressurized gas in-between the rotary ram-in compressor stages, to improve the operating efficiency of the compressor.
FIG. 4 is a sectional view in a schematic representation of another exemplary embodiment of a rotary ram-in compressor, used for pressurizing a gas into a container, in accordance with the present invention.
The main components of the rotary ram-in compressor in this embodiment are a stationary casing (71) having an inlet passage (72) for admission of the gas to be pressurized (73), and a receiver (74) wherein pressurized gases (75) collect; a conduit (76) for communicating the receiver (74) with the said container (not shown in the drawing for simplicity), wherein the pressurized gas (75) collects; a drive shaft (77) supported for rotation in a given direction inside the casing by an arrangement of bearings (78), and extending to a drive receiving end located outside the casing; and a rotor assembly (79) housed inside the casing and secured for rotation with the drive shaft (77), with the design and operating principals of the rotor assembly (79) in this embodiment being similar to that of the first rotary ram-in compressor stage of the embodiment of FIGS. 1,2.
In operation, gas is rammed through the feeding channels the compressor's rotor (79), which displace it in a generally radially outward direction to the compressor's receiver (74), from which it flows through the conduit (76) to the container, wherein it collects.
The embodiment also includes a valve (80) for controlling the flow of gas through the conduit (76) communicating the receiver (74) with the container, and a pressure sensor (81) for detecting the degree of rise in the pressure of gas within the compressor's receiver (74). Once a predetermined pressure level is reached within the compressor's receiver (74), the pressure sensor (80) sends correlative signals to a stepping motor (82) to close the valve (80), and to turn off the driving means used for driving the compressor's rotor (not shown in the drawing for simplicity).
FIGS. 5-10 are schematic representations of alternatives in which the feeding channels confined between the opposing parts of the surfaces of the adjacent vanes of a rotary ram-in compressor in accordance with the present invention, may be designed.
As discussed herein before, the boundaries of each of the feeding channels are formed of the opposing parts of the surfaces of the two adjacent vanes confining the channel between them (right front and left rear surfaces of the drawings), and of the opposing parts of the disks' surfaces related to the channel and confined between the opposing parts of the surfaces of the two adjacent vanes.
In FIG. 5 each two opposing surfaces (91,92 & 93,94), of those defining the feeding channel between them, are parallel to one another, with the cross-sectional area of the inlet of the channel being equal to the cross sectional area of its outlet.
In FIG. 6 the feeding channel is slightly converging from its inlet towards its outlet. The convergence of the feeding channel is provided by designing the boundaries confining the channel between them so that the axial width of the channel decreases gradually from the inlet of the channel towards its outlet, with the gradual decrease in the axial width of the channel provided by designing one (95) of the opposing parts of the disks' surfaces related to the channel and confined between the opposing parts of the surfaces of the two adjacent vanes so that it is gradually sloping from the inlet of the channel towards its outlet.
In FIG. 7 the feeding channel is slightly converging from its inlet towards its outlet. The convergence of the feeding channel is provided by designing the boundaries confining the channel between them so that the axial width of the channel decreases gradually from the inlet of the channel towards its outlet, with the gradual decrease in the axial width of the channel provided by designing both (96,97) of the opposing parts of the disks' surfaces related to the channel and confined between the opposing parts of the surfaces of the two adjacent vanes so that they are gradually sloping from the inlet of the channel towards its outlet.
In FIG. 8 the feeding channel is slightly converging from its inlet towards its outlet. The convergence of the feeding channel is provided by designing the boundaries confining the channel between them so that the axial width of the channel and the width between the opposing parts of the surfaces of the two adjacent vanes (99,100) confining the channel between them decrease gradually from the inlet of the channel towards its outlet, with the gradual decrease in the axial width of the channel provided by designing one (98) of the opposing parts of the disks' surfaces related to the channel and confined between the opposing parts of the surfaces of the two adjacent vanes so that it is gradually sloping from the inlet of the channel towards its outlet, and with the gradual decrease in the width between the opposing parts of the surfaces of the two adjacent vanes (99,100) provided by designing the vanes with suitable angles of inclination at their different parts, according to the desired angle of convergence of the channel.
In FIG. 9 the feeding channel is slightly converging from its inlet towards its outlet. The convergence of the feeding channel is provided by designing the boundaries confining the channel between them so that the axial width of the channel and the width between the opposing parts of the surfaces of the two adjacent vanes (103,104) confining the channel between them decrease gradually from the inlet of the channel towards its outlet, with the gradual decrease in the axial width of the channel provided by designing both (101,102) of the opposing parts of the disks' surfaces related to the channel and confined between the opposing parts of the surfaces of the two adjacent vanes (103,104) so that they are gradually sloping from the inlet of the channel towards its outlet, and with the gradual decrease in the width between the opposing parts of the surfaces of the two adjacent vanes provided by designing the vanes with suitable angles of inclination at their different parts, according to the desired angle of convergence of the channel.
In FIG. 10 the feeding channel is slightly converging from its inlet towards its outlet. The convergence of the feeding channel is provided by designing the boundaries confining the channel between them so that the width between the opposing parts of the surfaces of the two adjacent vanes (105,106) confining the channel between them decreases gradually from the inlet of the channel towards its outlet, with the gradual decrease in the width between the opposing parts of the surfaces of the two adjacent vanes (105,106) provided by designing the vanes with suitable angles of inclination at their different parts, according to the desired angle of convergence of the channel.

Claims

1. A rotary ram-in compressor, used for pressurizing a gas into a container, said rotary ram-in compressor comprising:

a stationary casing having at least one inlet passage for admission of the gas, and a receiver;

at least one conduit for communicating the said receiver with the said container;

a drive shaft supported for rotation in a given direction inside the casing by an arrangement of bearings, and extending to a drive receiving end located outside the casing; and

a rotor assembly housed inside the casing and including a first disk secured for rotation with the drive shaft and lying in a first plane transverse to the rotational axis of the drive shaft; a second disk lying in a second plane transverse to the rotational axis of the drive shaft, with the inner surfaces of the two disks defining an annular space in-between; and a plurality of vanes arranged circumferentially within said annular space, each vane attached to both disks defining the annular space, each vane has a leading edge, a trailing edge, a concave surface and a convex surface, with the average angles of inclination of the successive portions of the vane with respect to a plane comprising the midpoint of the vane and perpendicular to a radial plane including the rotational axis of the rotor and the midpoint of the vane decreases preferably gradually from its leading edge towards its trailing edge, within a range from about +18 to about −18 degrees, the opposing parts of the surfaces of each two adjacent vanes along with the opposing parts of the two disks' surfaces confined between the opposing parts of the surfaces of each two adjacent vanes defining a feeding channel between them, each feeding channel has an inlet communicating with the compressor's inlet passage and an outlet communicating with the compressor's receiver.

2. The rotary ram-in compressor of claim 1, wherein the cross sectional area of the inlet of each of the said feeding channels equals the cross sectional area of its outlet

3. The rotary ram-in compressor of claim 1, wherein each of the said feeding channels converges from its inlet towards its outlet

4. The rotary ram-in compressor of claim 1, wherein the said conduit communicating the compressor's receiver with the container is provided with valve means for controlling the flow of gas through the conduit.

5. The rotary ram-in compressor of claim 1, which further comprises at least one pressure sensor for detecting the degree of rise in the pressure of gas supplied by the rotary ram-in compressor.

6. A rotary ram-in compressor, used for pressurizing a gas into a container, said rotary ram-in compressor comprising:

a rotor assembly housed inside the casing and functionally divided into at least two successive rotary ram-in compressor stages, each of the rotary ram-in compressor stages includes a first disk secured for rotation with the drive shaft and lying in a first plane transverse to the rotational axis of the drive shaft; a second disk lying in a second plane transverse to the rotational axis of the drive shaft, with the inner surfaces of the two disks defining an annular space in-between; and a plurality of vanes arranged circumferentially within said annular space, each vane attached to both disks defining the annular space, each vane has a leading edge, a trailing edge, a concave surface and a convex surface, with the average angles of inclination of the successive portions of the vane with respect to a plane comprising the midpoint of the vane and perpendicular to a radial plane including the rotational axis of the rotor and the midpoint of the vane decreases preferably gradually from its leading edge towards its trailing edge, within a range from about +18 to about −18 degrees, the opposing parts of the surfaces of each two adjacent vanes along with the opposing parts of the two disks' surfaces confined between the opposing parts of the surfaces of each two adjacent vanes defining a feeding channel between them, each feeding channel has an inlet and an outlet, with the inlets of the feeding channels of the first rotary ram-in compressor stage communicating with the said compressor's inlet passage, and with the outlets of the feeding channels of the last rotary ram-in compressor stage communicating with the said compressor's receiver.

7. The rotary ram-in compressor of claim 6, wherein the cross sectional area of the inlet of each of the said feeding channels equals the cross sectional area of its outlet

8. The rotary ram-in compressor of claim 6, wherein each of the said feeding channels converges from its inlet towards its outlet.

9. The rotary ram-in compressor of claim 6, wherein the said conduit communicating the compressor's receiver with the container is provided with valve means for controlling the flow of gas through the conduit.

10. The rotary ram-in compressor of claim 6, which further comprises at least one pressure sensor for detecting the degree of rise in the pressure of gas supplied by the rotary ram-in compressor.