WO2003085267A1

WO2003085267A1 - A unit consisting of a compressor element and a pressure vessel and a connection pipe therefor

Info

Publication number: WO2003085267A1
Application number: PCT/BE2003/000042
Authority: WO
Inventors: Karel Frans Clothilde M. Segers
Original assignee: Atlas Copco Airpower, Naamloze Vennootschap
Priority date: 2002-04-09
Filing date: 2003-03-13
Publication date: 2003-10-16
Also published as: WO2003085267A8; BE1014751A3; AU2003215450A1

Abstract

This invention relates to a unit comprising a compressor element (1) being provided with an outlet (2) for the compressed gas, a pressure vessel (3) provided at the top, and higher than said outlet (2), with an inlet (4) for this gas, and a fluid connection (5) between said outlet (2) and inlet (4) comprising a connection pipe (11) which is seated with its extremities in connection pieces (12, 13) connecting to the inlet (4), the outlet (2), respectively. The connection pipe (11) comprises at least two rigid parts (18, 19) with a gap (21) therebetween, said parts, at one extremity, being connected to each other at their outer side by means of an elastically deformable sleeve (20) sealing the gap (21) between the two rigid parts (18, 19) in a leak-free manner.

Description

A unit consisting of a compressor element and a pressure vessel and a connection pipe therefor.

This invention relates to a unit consisting of a compressor element and a pressure vessel connected thereto, said unit comprising a compressor element being provided with an outlet for the compressed gas, a pressure vessel provided at the top, and higher than said outlet, with an inlet for said gas, and a fluid connection between said outlet and inlet comprising a connection pipe seated with its extremities in connection pieces connected to the inlet, the outlet, respectively.

In a compressor installation, the motor and the compressor element cause relatively many vibrations. In order to restrict vibrations and noise in the remainder of the installation and in the environment, the vibrations of the compressor element and the motor must be insulated as much as possible from the frame or the housing of the installation.

For these reasons, the compressor element and the motor are placed on rubber buffers.

However, there are always connections required between the vibrating compressor element and the fixed part of the installation, such as cooling circuits and the connection between the outlet of the compressor element and the pressure vessel, which normally is fixedly installed.

These connections must have the necessary flexibility, and for most connections, a simple plastic pipe or tube may offer a solution. This, however, is not the case for the fluid connection between said outlet and inlet, in consideration of the fact that a high pressure resistance is required. Those pressures may be higher than 10 bar at temperatures which may be above 100^°C.

Although tubes exist which are resistant against the relatively high pressures of the fluid, those tubes, however, are relatively expensive.

As a freedom of movement of several millimeters of the compressor element in respect to the pressure vessel is sufficient, in known fluid connections therebetween use is made of a straight connection pipe which, by means of seals, is seated with both extremities in connection pieces which connect to the outlet of the compressor element, the inlet of the pressure vessel, respectively. .

Moreover, it was found that a connection pipe counteracts the vibrations better than a flexible tube would, presumably because the column of compressed gas prevailing in the pipe exerts a pressure onto the pressure vessel. In a tube, this force is taken up by the walls.

Said seals mostly are 0-rings surrounding the extremities of the connection pipe in a wider receiving extremity of a connection piece.

Vibrations , in particular during the stationary run of the compressor element and during starting and stopping and during transport, are the cause for relative movements being created between the connection pipe and both seals, said movements causing a relatively fast wear and tear of these seals and of the surfaces of the pipe, in particular in dust-rich environments, with as a result that leaks are created. In order to restrict this, dust caps are already provided on the extremities of the pipe, however, this restricts the problem in a limited manner only.

The invention aims at a unit consisting of a compressor element and a pressure vessel which does not show the aforementioned disadvantage and whereby the fluid connection between the compressor element and the pressure vessel efficiently prevents the transmission of vibrations, has a long service life and still is relatively inexpensive.

According to the invention, this aim is achieved in that the connection pipe comprises at least two rigid parts with a gap in between, said parts, at one extremity, being connected to each other at the outer side by means of an elastically defor able sleeve, in particular a rubber sleeve sealing the gap between the rigid parts in a leak-free manner.

Adjustment deviations and vibrations are taken up by the elastically deformable sleeve.

Preferably, the sleeve is manufactured of an elastically deformable material, in particular rubber or elastomer.

Thereby, this sleeve practically is surrounded by a rigid mantle, preferably of metal, which is adhered to the elastic material.

This rigid mantle protects and supports the elastic material at the exterior thereof and thus prevents the bending out thereof as a result of the pressure in the connection pipe. The mantle also provides for that the elastic material takes up shifting forces over the entire height of the sleeve and not only at the location of the gap.

The extremities of the connection pipe can be seated in the connection pieces in the known manner, by the intermediary of seals, such as O-rings.

As a consequence of the elastically deformable sleeve, the extremities of the pipe shall not be displaced in respect to the seals, so that there will be no wear and tear.

Preferably, the connection pipe is tensioned between the connection pieces, such that, in the non-operated condition of the unit, the elastic sleeve partially is elastically compressed and has a certain pretension.

In a preferred embodiment, the elastically deformable sleeve is situated offset in respect to the center of the connection pipe, closer to one of the extremities than to the other.

Hereby, the bending-out of the connection pipe is avoided.

The invention also relates to a connection pipe clearly intended for being used in the above-described unit according to the invention.

The invention thus relates to a connection pipe comprising at least two rigid parts which, at one extremity, are connected to each other at the outer side by an elastically deformable sleeve, in particular a rubber sleeve sealing the gap between the two parts in a leak-free manner.

With the intention of better showing the characteristics of the invention, hereafter, as an example without any limitative character, a preferred form of embodiment of a unit consisting of a compressor element and a pressure vessel connected thereto and of a connection therefor, according to the invention, is described with reference to the accompanying drawings, wherein:

Figure 1 represents a view in perspective and with the parts in dismounted condition, of a unit according to the invention; figure 2 represents a side view of the unit from figure 1, mounted on a frame of a housing; figure 3, at a larger scale, represents a cross- section according to line III-III in figure 2.

The unit represented in figures 1 and 2 substantially consists of a compressor element 1, which at the bottom is provided with an outlet 2 for compressed gas, a pressure vessel 3 provided at the top with an inlet 4 for compressed gas, and a fluid connection 5 between said outlet 2 and inlet 4.

The compressor element 1 is an oil-injected element and is driven by a motor 6 fixedly mounted thereto. At the bottom, it is mounted, by the intermediary of rubber buffers 7 , on the frame 8 of a housing which further is not represented in figure 2.

The pressure vessel 3 is fixedly mounted, standing upright, on this frame 8. This pressure vessel 3 is provided with an outlet 10 in its cover lid 9.

The fluid connection 5 consists of a connection pipe 11 and connection pieces 12 and 13, between which this connection pipe 11 is seated. The upper connection piece 12 is an elbow joint which, with one leg 12A, is fixed to the pressure vessel 3 and connects to the inlet 4. The upper extremity with reduced diameter of the connection pipe 11 is surrounded by a seal, to wit a rubber O-ring 14, and protrudes into the downwardly directed extremity of the other leg 12B of the connection piece 12.

The lower connection piece 13 is a pipe bent in a U-shape having two upwardly directed legs 13A and 13B, however, between those a bottom part 13C. At one extremity, the one upwardly directed leg 13C is provided with a flange 15. By means of not-represented bolts, by the intermediary of a rubber O-ring 16, this flange 15 is attached to the outlet 2 situated in the lower part of the compressor element 1. The other, upwardly directed leg 13B takes up the connection pipe 11.

In a manner analogous to the upper extremity, the lower extremity of this connection pipe 11, also with a reduced diameter and surrounded by a seal , such as a rubber 0- ring 17, protrudes in this leg 13B of the connection piece 13.

According to the invention, the connection pipe 11 consists of two rigid metal parts 18 and 19, which are connected to each other by a sleeve 20 of natural or synthetic rubber or elastomer.

The lower part 19 is visibly shorter than the upper part 18, which means that the gap 21 in between is not situated in the center of the connection pipe 11, but visibly closer to the lower extremity thereof, and preferably as close as possible to this lower extremity.

In a variant, the gap 21 is situated closer, and preferably as close as possible, to the upper extremity instead of the lower.

The rubber sleeve 20 is vulcanized directly upon the outer side of the lower part 19, against a collar 22.

The part of the sleeve 20 protruding beyond this part 19 is vulcanized onto a metal inner ring 23. This inner ring 23 surrounds the lower extremity of the upper part 18 in a narrow fit, without protruding beyond this extremity. Said inner ring 23 is glued to this extremity by means of metal glue, in particular anaerobic glue, for example, of the trademark LOCTITE.

In this manner, the sleeve 20 thus is firmly fixed to the parts 18 and 19 of the connection pipe 11. Using the inner ring 23 instead of vulcanizing the rubber ring directly onto the part 18 prevents that the vulcanization mould must be large and thus would be expensive. Moreover, different lengths of the connection pipe 11 can be manufactured, without having to use another vulcanization mould.

In a variant, the sleeve 20, instead of directly, also can be fixed at the lower part 19 in a manner analogous to the fixation at the part 18, by the intermediary of an inner ring. In another variant, the sleeve 20 can be glued to the lower part.

As can be seen in particular in figure 3, the rubber sleeve 20 is protected by a metal mantle 24 which has been applied during the vulcanization of the rubber and provides for a physical support of the rubber. Rubber or another visco-elastic material is sensitive to creep. The metal mantle 24 supports this material and provides for a longer stability thereof. As already mentioned, the mantle 24 allows for that the rubber takes up shear forces over the entire height of the sleeve 20 and not only in respect to the gap 21.

In a variant, the mantle 24 is glued to the sleeve 20.

In non-operating condition of the connection pipe 11, thus, when the compressor element 1 is at a standstill, the rubber sleeve 20 is pretensioned and thus somewhat compressed. This is a result of the choice of the length of the connection pipe 11 and the fact that the pressure vessel 3 is slid with its connection piece 12 on the upper extremity of the connection pipe 11, after this latter already has been connected at its lower end to the compressor element 1 , by means of the other connection piece 13.

The rubber sleeve 20 takes up small adjustment deviations and vibration movements. The gap 21 is sufficiently small to allow this taking up, however, still preventing the buckling of the connection pipe. The width of the gap 21 is situated, for example, between 2 and 5 mm, and preferably is 4 mm.

The sleeve 20 also dampens the vibrations of the compressor element 1 and the motor 6 to a considerable extent. The noise level of the compressor element 1 is reduced, too. The pressure vessel 3 may act as a resonance vessel, however, now it is no longer possible to transmit any direct vibrations by means of a metal contact with the compressor element 1.

Due to the sleeve 20, the connection pipe 11 will not move in respect to the 0-rings 14 and 17, such that those have a long service life. The gap 21 creates an axial degree of freedom. During normal operation, a column of gas under pressure is present in the connection pipe 11, said column exerting a force on the pressure vessel 3.

The sleeve 20 may be manufactured of another elastic material than rubber, in particular an elastomer. Instead of being fixed on the part 19 or the inner ring 23 by means of vulcanization, the elastomer is fixed thereon by means of polymerization, whereas the attachment to the outer mantle 24 then, too, is performed by polymerization on this latter, instead of vulcanization.

The connection pipe 11 does not necessarily have to be vertically directed. It may also be installed inclined.

The connection pipe 11 may also consist of more than two rigid parts 18 and 19 connected by a sleeve 20, for example, three, with a sleeve 20 next to the lower extremity and a sleeve 20 next to the upper extremity. This even may increase the flexibility.

The invention is in no way limited to the form of embodiment described heretofore and represented in the accompanying drawings, however, such unit consisting of compressor element and pressure vessel can be realized in various variants , without leaving the scope of the invention .

Claims

Claims .

1.- A unit consisting of a compressor element and a pressure vessel connected thereto, said unit comprising a compressor element (1) being provided with an outlet (2) for the compressed gas, a pressure vessel (3) provided at the top, and higher than said outlet (2), with an inlet (4) for this gas, and a fluid connection (5) between said outlet (2) and inlet (4) comprising a connection pipe (11) which is seated with its extremities in connection pieces (12,13) connecting to the inlet (4), the outlet (2), respectively, characterized in that the connection pipe (11) comprises at least two rigid parts (18,19) with a gap (21) therebetween, said parts, at one extremity, being connected to each other at the outer side by an elastically deformable sleeve (20) sealing the gap (21) between the two rigid parts (18,19) in a leak- free manner.

2.- A unit according to claim 1, characterized in that the sleeve (20) is manufactured of an elastically deformable material, in particular of rubber or elastomer.

3.- A unit according to claim 1, characterized in that the sleeve (20), at the outer side, is surrounded by a rigid, preferably metal, mantle (24) adhered to the elastic material.

4.- A unit according to any of the preceding claims, characterized in that the extremities of the connection pipe (11) are seated in the connection pieces (12,13) by the intermediary of seals (14,17).

5.- A unit according to claim 4, characterized in that the extremities of the connection pipe (11) are seated in the connection pieces (12,13) by the intermediary of O- rings (14,17).

6.- A unit according to any of the preceding claims, characterized that the connection pipe (11) is tensioned between the connection pieces (12,13), such that the elastic sleeve (20), in the non-operating condition of the unit, is partially compressed and thus has a certain pretension.

7.- A unit according to any of the preceding claims, characterized in that the elastically deformable sleeve (20) is situated offset in respect to the center of the connection pipe (11).

8.- A unit according to claim 7, characterized in that the elastically deformable sleeve (20) is situated closer to one of the extremities of the connection pipe (11) than to the other.

9.- A unit according to any of the preceding claims, characterized in that the rigid parts (12,13) of the connection pipe (11) are metal parts.

10.- A unit according to any of the preceding claims, characterized in that the sleeve (20) adheres to one of the parts (19), the portion thereof protruding beyond this part (19) adheres to a metal inner ring (23), which is glued around the extremity of the other part (18) by means of glue.

11.- A connection pipe for being used in the unit according to any of the preceding claims, characterized in that it comprises at least two rigid parts (12,13), said parts, at one extremity, being connected to each other at the outer side by means of an elastically deformable sleeve (20) sealing the gap (21) between the two parts (12,13) in a leak-free manner.

12.- A connection pipe according to claim 11, characterized in that the sleeve (20) consists of rubber or elastomer and, at its outer side, is surrounded by a rigid, preferably metal, mantle (24) adhering thereto.

13.- A connection pipe according to claim 11 or 12, characterized in that the sleeve (20) is made of rubber and is vulcanized onto a part (19) of the pipe, and the portion of the sleeve (20) protruding beyond this part (19) is vulcanized at the inside onto a metal inner ring (23) which is glued to the other part (18).