EP0646728B1

EP0646728B1 - Vortex compressor

Info

Publication number: EP0646728B1
Application number: EP94905268A
Authority: EP
Inventors: Vladimir Nikolaevich Khmara; Ljudmila Nikolaevna Belotelova; Vladimir Nikolaevich Sergeev
Original assignee: JOINT STOCK Co EN& FI
Current assignee: JOINT STOCK Co EN& FI
Priority date: 1992-12-29
Filing date: 1993-12-27
Publication date: 1998-08-12
Anticipated expiration: 2013-12-27
Also published as: EP0646728A4; EP0646728A1; WO1994015101A1

Abstract

A vortex compressor comprises a housing (1) which is provided with an annular operating channel, an inlet port (2) and a discharge port (3) connected to the annular operating channel, and a cut-off (4) situated between the inlet port (2) and the discharge port (3). The disk (5) of the operating wheel mounted in the housing (1) is provided with a vane rim (6) accomodated in the annular operating channel. The housing (1) and cut-off (4) are provided with interconnnecting openings (7 and 8) which are arch-shaped and eequidistant from the vane rim (6). The inlet and outlet edges of the vane rim (6) are arranged coaxially at the edge of the lateral face of the disk (5). The inlet port (2) is in the form of an opening which is bow shaped and equidistant from the vane rim (6) and situated towards the inlet edges of the vanes, while the opening (7) in the housing (1) and the opening (8) in the cut-off (4) are situated towards the outlet edges of the vanes. The opening (7), the opening of the inlet port (2) and the cut-off are arranged in three segments on a plane perpendicular to the axis of rotation of the disk (5). The segment of the opening of the inlet port (2) is adjacent to the segment of the cut-off (4). Part of the segment of the cut-off (4) coincides with the segment of the opening in the housing, and the opening (8) in the cut-off (4) is situated in the part of the segment of the opening (7) of the housing (1) which coincides with segment of the cut-off (4).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a field of machine building and can be utilized in compressors of a vortex type.

2. Description of the Prior Art

There is known a vortex compressor comprising a casing with an annular working channel having a suction and discharge ports, a shut-off device arranged in the channel between the ports, an impeller mounted in the casing, a disc of the impeller having a ring with the blades thereon, and the shut-off device has an orifice for gas removal (DE, A, 2409184).

In this design, gas, contained in the interblade space of the blading and heated in the process of compression, is partially released from the shut-off device through the orifice. This provides a reduction of an undesirable transfer of hot gas from a compressor suction side to a discharge one and an increase of the machine efficiency. The gas is removed from the shut-off device back to the working channel through said orifice along a special pipeline to a zone of an intermediate pressure. Although this design reduce a harmful impact of a ballast gas, it is not sufficient since hot gas under some intermediate pressure appears at the compressor suction side from the interblade space of the blading.

There is further known a vortex compressor comprising a casing wherein are formed an annular working channel, a suction and discharge ports communicating with the annular channel, a shut-off device arranged between the suction and discharge ports, an impeller mounted in the casing, on a disc of the impeller being mounted a ring of blades located in the annular working channel, wherein the casing and shut-off device comprise slots of arched shape, communicating therebetween and equidistant to the blading (SU, A, 328265).

In this design, a ballast hot gas from the interblade space is almost completely removed to an ambiemt air and excluded from the process of compression in the compressor. Said design provides blowing effect when owing to a specific arched shape and arrangement of the slot, the hot gas in the interblade space is replaced by cold gas entering from the atmosphere. Such a blowing ensures an essential increase of the machine efficiency, reduction of the gas temperature at the suction side due to lack of replenishment by a ballast hot gas, raise of a compression extent at this stage and improvement of weight output. In said design, the blowing extent depends substantially on a size of the arched slot. From the one hand, the reduction of an arched slot length results in incomplete blowing with all resulting sequences. From the other hand, although the increase of the arched slot length intensifies blowing, it can be attained only by increasing a portion of the annular channel occupied by the shut-off device since the arc is arranged within the margins of this portion. This results in reduction of the remaining portion of the working channel wherein the compression takes place as such, thereby reducing the efficiency of the compressor. Therefore, the efficiency of said design is limited by the blowing.

US-A-3 095 820 describes a reentry rotary fluid pump which is similar to the technical solution of the above mentioned USSR author's certificate number 328 265. Port 25 on figure 3 of said reference, is used exclusively for removing hot gas from the vane space of impeller 13. Owing to the relative position of inlet port 22 and port 25, the vane space of impeller 13 is blown before suction begins; this design has the same disadvantages as the solution described by the above mentioned author certificate.

EP-A-0 011 983 describes a regenerative rotodynamic machine having a rotary disk-like impeller having a portion adjacent its periphery that extends through an annular chamber machine casing concentric with the impeller, thereby dividing said chamber into two annular side channels one on each side of the impeller. In such a design the harmful impact of hot gas is reduced by using relieving passages 28 provided in the casing walls; in this case hot gas remains in the machine and is only diverted to other areas of chamber 13.

DE-C-902 074 describes a dynamic compressor with the side passage coaxial to the impeller. In the course of operation the compressed gas or vapour in the vane space passing through the shut-off are sent to the suction space of the compressor through passage p; in particular, this passage p together with the inlet pipe may form an ejector; hot gas from passage p is mixed with cold sucked in gas without displacing hot gas from passage d.

GB-A-2 068 461 describes a regenerative turbo machine which is provided with one or more breather passages in a stripper which separates the inlet port and outlet port of the toroidal channel in which the vanes or blades of its rotor rotate. Compressed gas from the impeller vane space in the shut-off area is diverted through passages to the suction space, thus forming a flow on suction by inducing jet action.

ESSENCE OF THE INVENTION

It is an object of present invention to provide a vortex compressor combining two gas dynamic blowing processes, namely, a removal of hot gas from a shut-off unit, and a suction, and thereby to intensify formation of a flow at the vortex compressor input and to extend a zone of an efficient compression process in an annular working channel, and thus, to raise an efficiency of the vortex compressor.

This object is attained by providing a vortex compressor according to claim 1.

Alternatively, a vortex compressor can be provided at the face wall of the shut-off unit, at the side of blades, with a recess opened to the shut-off unit slot.

Alternatively, a vortex compressor can be provided with an insert from a sound-absorbing material, mounted on a wall of the annular working channel opposite to the suction port slot and blades.

Alternatively, a vortex compressor can be provided with a baffle arranged radially in the working annular channel at the end of the casing slot for removing gas through the casing slot.

The disclosed advantages and peculiarities of the present invention will become more apparent from further description of the preferred embodiment of the invention with references to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematical representation of the vortex compressor,

Fig. 2 is a sectional view on the line A-A of Fig. 1,

Fig. 3 is a sectional view on the line B-B of Fig. 2,

Fig. 4 is a sectional view on the line C-C of Fig. 2.

DESCRIPTION OF THE PREFERRED EMBODIEMENT OF THE INVENTION

Illustrated in Fig. 1 and Fig. 2, a vortex compressor comprises a casing 1 wherein is made an annular working channel. A suction port 2 and discharge port 3 communicate with the annular working channel. A shut-off unit 4 is arranged between the suction port 2 and discharge port 3. An impeller is mounted in the casing 1 and on its disc 5 there is provided a ring 6 of blades, arranged in the annular working channel. In the casing 1 and shut-off unit 4 there are provided

slots

7 and 8, accordingly, for blowing through the shut-off unit 4. A slot 7 in the casing 1 and slot 8 in the shut-off unit 4 communicate therebetween, have an arched shape and are equidistant to the ring 6 of blades.

According to present invention, the input and output edges of the blades of the ring 6 are arranged coaxially at the end of the lateral face of the disc 5, accordingly, on the lesser diameter "d" and larger diameter "D". The suction port 2 is formed as a slot of an arched shape, equidistant to the blading 6 and arranged at the side of the input edges of blades, i.e. at the inner side with regard to the circle of a diameter "d". The slot 7 in the casing 1 and slot 8 in the shut-off unit 4 are located at the side of the output edges of the blades, i.e. at the outer side with regard to the circle of a diameter "D". The slot 7 in the casing 1, slot of the suction port 2 and the shut-off unit 4 are arranged in three sectors J1, J2, J3, accordingly (Fig.1), at a plane perpendicular to a pivot axis of the disc 5. The sector J2 of the suction port 2 is adjacent to the sector J3 of the shut-off unit 4. The portion of the sector J3 of the shut-off unit 4 is combined with the sector J1 of the slot 7 in the casing 1, and the slot 8 in the shut-off unit 4 is located in a portion of the sector J1 of the slot 7 in the casing 1 combined with the sector J3 of the shut-off unit 4.

In other words, the sector J1 overlaps a common margin of the two adjacent sectors J2 and J3.

In the face wall of the shut-off unit 4 (Fig. 3), at the side of the blades, there can be provided a recess 9 opened to the slot 8 in the shut-off unit 4. (In Fig. 2, a profile of the shut-off unit 4, occupied by the slot 8 of the shut-off unit 4 and recess 9 of the shut-off unit 4, is indicated by a dot-and-dash line).

A vortex compressor, as shown in Fig. 4, can be provided with an insert 10 of a sound-absorbing material, secured to a wall of the annular working channel opposite to the suction port 2 slot and blades.

Illustrated in Fig. 2, a vortex compressor can be provided with a baffle 11 arranged radially in the annular working channel at the end of the slot 7 in the casing 1 for removing gas through the slot 7.

In operation of the vortex compressor (Fig. 1 and 2), when revolving the disc 5 of the impeller, gas enters to the annular working channel of the casing 1 through the suction port 2. In the annular working channel, the blades of the ring 6 transmit energy to gas in the process of a helical vortex motion of a flow. The compressed gas is removed from the annular working channel through the discharge port 3. A portion of gas in the interblade space of the blading 6, compressed to the discharge pressure, is transferred by the blades to the shut-off unit 4. In the shut-off unit 4, the hot gas, after entering the portion of the sector J3 adjacent to the sector J2 and opened through the slot 8 in the shut-off unit 4 into the slot 7 in the casing 1, is transmitted from the interblade space of the blading 6 due to a pressure difference and centrifugal forces through the slot 7 in the casing 1 outside, and is thrown out to the atmosphere from the interblade space. In the sector J2 portion, adjacent to the sector J3 and opened to the slot 7, there takes place a blowing of the interblade space of the blading 6; the blades by their input edges catch a fresh cold gas from the suction port 2 and throw it out through the slot 7. It should be emphasized that simultaneously there is formed an intense gas flow through the blading 6 from its centre to the periphery. This process is important from the point of appearing further helical vortex motion of the flow in the annular working channel. As a result, the suction process, occuring in the portion of the sector J2, not occupied by the slot 7, is provided by the already formed flow, namely, from the centre to the periphery of the blading 6. Such a suction ensures appearance of the vortex motion in the annular working channel just after the suction port 2 and the gas flow aquires a spinning impulse. This raises the compression efficiency of the compressor since the vortex motion is a basic one for transferring an energy from the impeller to gas.

The disclosed effect is inherent only to the present design. For instance, according to SU, A, 328265, a flow is formed at a suction side from zero level since the slot for blowing is separated from the suction side by the shut-off unit area. A practice shows that forming of a vortex flow occupies an extensive part of the annular working channel along with the the suction port. That is why, saving the annular working channel for efficient gas compression results in an essential effect. It should be noted that the advantage of present invention as compared with the design of SU, A, 328265 resides also in that the blowing process is divided into two phases, namely, throwing the hot gas to a portion of the sector J3, opened to the slot 7, and blowing as such at a portion of the sector J2, opened to the slot 7. In so doing, there is excluded throwing out the hot gas, directed opposite to the blowing flow and hampering its forming. Ultimately, it gives a possibility to reduce angular dimensions of the sectors J1 and J2, required for a complete blowing and suction, i.e. to save the annular working channel and to improve efficiency of the compressor.

The recess 9 increases a size of the slot 8 providing more quick throwing of the hot gas from the interblade space of the blading 6 through the slot 7. It also ensures a reduction of angular dimensions of the sectors J1 and J2.

The blowing process is accompanied by a considerable noise. To reduce the noise and to direct the blowing flow to the interblade space of the blading 6, there can be provided an insert 10 from a sound-absorbing material.

Shutting off the blowing flow from the suction flow by a baffle 11 ensures more quick forming vortex in the annular working channel.

INDUSTRIAL APPLICABILITY

The present vortex compressor can be most successfully used in helical centrifugal turbocompressors and other pumps of non-volumetric replacement for gases and vapors with spinning motion, for instance, in blowers which require at the output thereof a gas with low temperature, in particular, for flour-milling.

Claims

A vortex compressor comprising a casing (1) wherein are formed an annular working channel, a suction port (2) and a discharge port (3), both communicating with the annular working channel, a shut-off unit (4) arranged between the suction port (2) and the discharge port (3), an impeller mounted in the casing (1), on a disc (5) of the impeller being provided a ring (6) of blades located in the annular working channel, wherein the casing (1) and the shut-off unit (4) are provided with slots (7) and (8) of arched shape, communicating therebetween and equidistant to the ring (6) of blades, characterized in that the input and output edges of blades of the ring (6) of blades are arranged coaxially at the end of a lateral surface of the disc (5), the suction port (2) is formed as a slot of arched shape, equidistant to the ring (6) of blades and arranged at the side of the input edges of the blades, and the slot (7) in the casing (1) and the slot (8) in the shut-off unit (4) are located at the side of the output edges of the blades; the slot (7) in the casing (1), the slot of the suction port (2) and the shut-off unit (4) are arranged in three sectors (J₁, J₂, J₃) at a plane perpendicular to a pivot axis of the disc (5), wherein the sector (J₂) of the suction port (2) slot is adjacent to the sector (J₃) of the shut-off unit (4), a portion of the shut-off unit (4) sector (J₃) is combined with the sector (J₁) of the slot (7) in the casing (1), and the slot (8) of the shut-off unit (4) is located in the portion of the slot (7) sector (J₁) in the casing (1), combined with the shut-off unit (4) sector (J₃).
The vortex compressor according to claim 1, characterized in that the face wall of the shut-off unit (4), at the side of the blades, is provided with a recess (9) opened to the slot (8) in the shut-off unit (4).
The vortex compressor according to claim 1, characterized in that it is provided with an insert (10) from a sound-absorbing material, arranged on the wall of the annular working channel opposite to the suction port (2) and blades.
The vortex compressor according to claim 1, characterized in that it is provided with a baffle (11) arranged radially in the annular working channel, at the end of the slot (7) in the casing (1), for removal of gas through the slot (7) in the casing (1).