EP2396552B1 - Muffler for a turbo or piston engine - Google Patents

Description

The invention relates to a silencer for a flow or piston machine, in particular for a screw compressor or expander, according to the preamble of claim 1.

During operation of flow and piston machines, frequent vibrations occur which are impressed, for example, by pressure fluctuations in the fluid, periodic excitations of the engine or the like and, in particular, lead to undesired sound radiation. In order to reduce the transmission and emission of sound, it is known to forward and / or downstream flow and piston machines or stages silencer, which are traversed by the fluid and thereby, usually dissipatively, reduce pressure fluctuations in the fluid.

From internal practice for this purpose, a silencer is known in the fluid flows around a central damper gate, which are housed in a housing, To reduce the transmission and radiation of sound, the housing is surrounded on its outside with a sand jacket.

The generic US 5 507 159 A discloses a collector assembly of a refrigerator compressor, wherein in the collector located in the disc elements at the ends of which cushions for vibration damping are present. In JP 2000 21 2228 A there is disclosed an exhaust muffler which provides damping members for sound attenuation at the ends of disk members connecting the muffler outer mantle to the inner exhaust pipe. Further silencers are in GB 2 389 150A . US 4 244 442 A and FR 2 869 949 A1 described.

The object of the present invention is to provide an improved silencer for a flow or piston machine, in particular for a screw compressor.

To solve this problem, a silencer according to the preamble of claim 1 is further developed by the characterizing features of claim 1.

Claim 10 provides a method for producing a special embodiment of the silencer according to the invention under protection, the further subclaims relate to advantageous developments.

The present invention is based, on the one hand, on the recognition that the previous cladding with sand does not optimally damp vibrations of the housing since the sand does not uniformly bear everywhere due to the gravitational effect. Therefore, it is proposed according to a preferred embodiment of the invention to cover the housing on its outside by a vibration-damping jacket made of dimensionally stable material, so that there is a uniform contact between the housing and the jacket. Advantageously, the use of dimensionally stable material can also simplify the attachment of the shell to the housing.

On the other hand, the present invention takes into account the fact that structure-borne noise in silencers, as they have been used according to in-house practice, takes place in the frequency ranges relevant in the operation in substantial proportions on the inner tubes, so that the sole damping of the housing on its outside by the Sandmantel the transmission and radiation of sound is not optimally reduced. Therefore, it is proposed according to the invention, which may be particularly preferably combined with the above-described shell of dimensionally stable material, to arrange between a pipe assembly and the housing an elastic, vibration damping and disc-shaped element. As a result, the tube arrangement can be partially decoupled in terms of vibration technology and, in particular, a transmission of structure-borne noise can thus be reduced.

An inventive silencer is provided for a flow or piston machine, in particular a compressor, and is used with particular advantage in screw compressors, which are exposed to strong periodic vibration excitation due to their mechanism of action, It comprises a single, or preferably, multi-part housing, a tube assembly with one or, preferably, a plurality of tubes for guiding a fluid of the flow or. Piston machine, such as a process gas, a liquid or the like, and a disc assembly with one or, preferably a plurality of discs which are releasably clamped, for example by a screw frictionally clamped or insoluble, for example by welding, are attached to the housing and carry the tubes of the tube assembly , In particular, one or more disks may also be formed, at least in part, integrally with the housing, for example, be formed or formed.

According to the present invention, at least one elastic, vibration-damping element is arranged between the tube arrangement and the housing in order to at least partially decouple the tube arrangement with respect to the housing in terms of vibration technology. One or more, preferably all, elastic elements are designed so that they absorb vibrations and, for this purpose, preferably have higher damping constants with regard to relevant frequency ranges. A higher damping constant can be characterized for example by a sufficiently large amplitude reduction in the frequency response of the muffler in the range of relevant frequencies. In particular, an elastic element made of an elastomer, a thermoset or thermoset or sealing materials, which are also used for flange connections exist.

Due to the vibration decoupling resonance frequencies of the muffler and amplitude peaks in its frequency response, ie the vibration response to excitations on the frequency of the excitation shifted, and thus the transmission and emission of sound can be reduced. By vibration-damping elements, additional vibration energy can be dissipated, thus further reducing the transmission and emission of sound.

One or more, preferably all discs of the disc assembly have an elastic element. For this purpose, for example, a disk-shaped, elastic element, for example made of a plastic such as polystyrene, sealing materials or other viscoelastic material, in particular made of rubber, on a metal layer of the disc, preferably insoluble, attached, for example, hereby glued, vulcanized or sprayed. Each two Metalliagen surrounded sandwich a disc-shaped elastic element.

By the, preferably thin, metal layers and the elastic member, the discs are bending or völbelastisch and thus decouple the tubes relative to the housing. In addition, a vibration damping member on the disks dissipates vibratory energy in both the tubes suspended from the discs and vibrational energy in the fluid impinging on the discs.

Additionally or alternatively, it is also possible to arrange elastic, preferably vibration-damping elements between one or more, preferably all disks and the pipe arrangement.

In a preferred embodiment, the tube assembly is frictionally secured to the disc assembly by, for example, tubes of the tube assembly in bores or sleeves are pushed or pushed, which are formed in slices or attached thereto. Then elastic, preferably vibration damping elements, for example made of plastic, rubber or other viscoelastic materials can be arranged in the contact region between the tube and disc. By such a frictional clamping connection also advantageously the assembly and disassembly of the muffler can be simplified.

Preferably, one or more, preferably all tubes of the tube assembly have openings transverse to a direction of flow. For this purpose, pipes can be made, for example, from perforated plates, wire mesh or the like. The fluid flowing through these openings reduces vibrations, and the thermodynamic property and weight of the muffler are improved.

Between pipes of the pipe arrangement: but also within some pipes damping material, such as mineral wool, may be arranged to further dampen vibrations in the fluid.

Preferably, the diameter of the tubes is chosen so small that transverse modes can be reduced in the muffler, this is the product of, in particular hydraulic, diameter D of the tube, the circle number π; and the ejection frequency f _{A of} the flow or piston machine advantageously at most twice, in particular at most 1.8 times the speed of sound c of the fluid of the flow or piston machine, so that the following applies: $$D<\frac{1.\mathrm{8th}\cdot c}{f_A\cdot \pi }\mathrm{,}$$

Nevertheless, in order to realize a sufficient total cross-section of the muffler, in a preferred embodiment several, in particular at least three, tubes are preferably distributed equidistant over the circumference of the housing.

According to a further embodiment, the housing may be completely or partially covered on its outside with a vibration-damping jacket of dimensionally stable material. This coat shifts on the one hand its mass resonance frequencies of the muffler and amplitude peaks in its frequency response, on the other he attenuates in particular higher-frequency vibrations. In contrast to sand shells, the dimensionally stable material thereby improves the contact and thus the vibration-technical coupling with the housing. In addition, it has been found that dimensionally stable material has better damping properties.

Another advantage of dimensionally stable jacket material is that, in contrast to sand, it can be arranged better on the housing. Preferably, it may be applied to the housing in a liquid or viscous state, for example by spraying it on or immersing the housing in a bath of dimensionally stable material, and then solidifying it on the housing, for example by itself, with the addition of heat, in reaction with air. or cure by addition of crosslinking agent.

Preferably, the dimensionally stable material is adhesive, i.e. adheres to other surfaces. This further improves the contact and thus the vibration control coupling with the housing even further and also simplifies the attachment to the housing.

As particularly suitable dimensionally stable and adhesive materials which have both good damping properties and are easy to handle, fiber cement mortar or plastic, in particular polyurethane have shown.

Fig. 1:

die obere Hälfte eines Schalldämpfers nach einer Ausführung der vorliegenden Erfindung im Längsschnitt.

Further advantages and features emerge from the subclaims and the exemplary embodiment. This shows, partially schematized, the only one

Fig. 1:

the upper half of a muffler according to an embodiment of the present invention in longitudinal section.

Fig. 1 shows the upper half of a muffler according to an embodiment of the present invention in longitudinal section. It comprises a three-part housing with an upstream in the flow direction front housing part 1.1, one with this via flanges, as in Fig. 1 indicated by dash-dotted lines, screwed middle part 1.2 and a downstream rear housing part 1.3, which is formed substantially symmetrically to the front housing part 1.1 and is also bolted to the central part 1.2 via flanges.

Between the flanges of the front housing part 1.1 and middle part 1.2 or middle part 1.2 and rear housing part 1.3, a disc 3 or 4 of a disc assembly is frictionally clamped These discs are constructed in three parts and each comprise an elastic disc 3.3 or 4.3, which sandwiched between metal layers 3.1, 3.2 and 4.1, 4.2 added and connected to them. The elastic discs 3.3, 4.3 are made of polystyrene and glued to the metal layers 3.1, 3.2 and 4.1, 4.2.

The disks 3, 4 have three evenly distributed over the inner circumference of the housing bores, which are penetrated by sleeves 3.4 and 4.4 respectively. These sleeves have on their inner circumference a paragraph and are welded on its outer periphery with the discs 3 and 4, as in Fig.1 indicated in a customary manner by filled triangles.

Approximately in the middle of the housing 1 another, one-piece disc 5 is welded, which has aligned with the holes of the discs 3, 4 holes in the sleeves 5.1 are also inserted, which have on their inner circumference a central, inwardly projecting shoulder and are welded to the disc 5. This disc increases the stiffness of the muffler and in particular counteracts vibrations.

Three parallel pairs of aligned tubes, of which in the upper longitudinal section of the Fig. 1 only one pair 2.1, 2.2 is shown, with their end faces in each of the sleeves 3.4, 5.1 and 5.1, 4.4 frictionally inserted and held by this clamped in the housing 1, which advantageously also a balance of different, for example thermally induced, length changes of housing 1 and tubes 2 allows .. Between sleeve inner and outer tube circumference is in each case a viscoelastic element in the form of a rubber or plastic ring 6, 7 and 8 respectively. The tubes 2.1, 2.2 are made of perforated metal.

Substantially on the entire outer peripheral surface of the middle part 1.2, a dimensionally stable jacket 9 made of fiber cement mortar or polyurethane is applied.

• durch das Durchströmen der gelochten Rohre 2.1, 2.2 werden Druckpulsationen im Fluid gedämpft;
• durch die Aufhängung an Scheiben 3, 4 mit viskoelastischen Mittelschichten 3.3, 4.3 im Gehäuse 1 und die reibschlüssige Befestigung über viskoelastische Hülsen 6, 7, 8 an den Scheiben 3, 4 und 5 sind die Rohre 2.1, 2.2 gegen das Gehäuse 1 schwingungstechnisch im Wesentlichen entkoppelt, wobei weitergeleitete Schwingungen, insbesondere Körperschall, zusätzlich durch Verformungsarbeit der viskoelastischen Elemente 3.3, 4.3, 6, 7 und 8 dissipiert wird;
• die insoweit als schalltote Bleche wirkenden Scheiben 3,4 dämpfen Schwingungen im Fluid; und
• der formbeständige Mantel 9 dämpft zusätzlich Schwingungen im Gehäuse 1.

The muffler is capable of pressure pulsations in the fluid, which for example from a screw compressor (not shown) in the muffler is promoted, to attenuate and also to reduce the transmission and emission of structure-borne noise effectively:

• by the flow through the perforated tubes 2.1, 2.2 pressure pulsations are damped in the fluid;
• by the suspension of discs 3, 4 with viscoelastic middle layers 3.3, 4.3 in the housing 1 and the frictional attachment via viscoelastic sleeves 6, 7, 8 on the discs 3, 4 and 5, the tubes 2.1, 2.2 against the housing 1 vibration substantially decoupled, wherein forwarded vibrations, in particular structure-borne noise, in addition by deformation work of the viscoelastic elements 3.3, 4.3, 6, 7 and 8 is dissipated;
• the so far as sound-deadening sheets acting discs 3,4 damp vibrations in the fluid; and
• the dimensionally stable jacket 9 additionally dampens vibrations in the housing 1.

The aforementioned measures interact favorably together. Nevertheless, an advantageous noise reduction can already be achieved by one of these measures. Thus, for example, in a modification, not shown, the tubes 2.1, 2.2 directly, ie without the interposition of viscoelastic sleeves 6 to 8, be plugged into the sleeves 3.4, 4.4 and 5.1, which advantageously improve the fatigue strength of the muffler and the assembly and disassembly can. Alternatively, the jacket 9 can be omitted from dimensionally stable material.

LIST OF REFERENCE NUMBERS

1.1-1.3

housing parts

3

disc

3.1,3.3

metal sheet

3.3

elastic element

3.4

shell

4

disc

4.1, 4.3

metal sheet

4.3

elastic element

4.4

shell

5

disc

5.1

shell

6-8

elastic element

9

coat

Claims (10)

1. A silencer for a turbo or piston machine, with:

   - a housing (1.1-1.3);

   - a disc arrangement with at least one disc (3, 4, 5), which is attached to the housing; and

   - a pipe arrangement attached to the disc arrangement with at least one pipe (2.1, 2.2) for conducting a fluid of the turbo or piston machine, wherein

   - between the pipe arrangement and the housing at least one elastic element (3.3, 4.3, 6, 7, 8) formed in a vibration-damping manner is arranged, and wherein

   - a disc (3.4) of the disc arrangement comprises an elastic and disc-shaped element (3.3, 4.3) formed in a vibration-damping manner, characterized in that a disc (3, 4) of the disc arrangement comprises at least one metal layer (3.1, 3.2, 4.1, 4.2) and an elastic and disc-shaped element (3.3.4.3) designed in a vibration-damping manner attached thereon, wherein two metal layers each surround an elastic and disc-shaped element formed in a vibration-damping manner sandwich-like.
2. The silencer according to any one of the preceding claims, characterized in that between the disc arrangement and the pipe arrangement an elastic element (S, 7, 8) formed in a vibration-damping manner is arranged.
3. The silencer according to any one of the preceding claims, characterized in that the pipe arrangement is attached to the disc arrangement in a frictionally joined manner.
4. The silencer according to Claim 3, characterized in that the disc arrangement comprises a sleeve (3.4.4.4, 5, 1), in which a pipe (2.1, 2.2) of the pipe arrangement is received in a frictionally joined manner.
5. The silencer according to any one of the preceding claims, characterized in that a pipe (2.1) of the pipe arrangement comprises openings transversely to a through-flow direction.
6. The silencer according to any one of the preceding claims, characterized in that within and/or outside the pipe arrangement damping material is arranged.
7. The silencer according to any one of the preceding claims, characterized in that the product of a circumference (Dπ) of a pipe of the pipe arrangement and an expulsion frequency (f_A) of the turbo or piston machine maximally amounts to twice, in particular maximally 1.8 times the speed of sound (c) of the fluid of the turbo or piston machine (D < 1.8c / {f_Aπ) < 2c / f_Aπ).
8. The silencer according to any one of the preceding claims, characterized by a vibration-damping jacket (9) of dimensionally stable material, which at least partly covers the housing (2.2) on its outside.
9. The silencer according to Claim 8, characterized in that the dimensionally stable material comprises fibre cement mortar or plastic.
10. A method for producing a silencer according to any one of the Claims 8 or 9, characterized in that the dimensionally stable material is applied onto the housing in the liquid state where it solidifies.

Images