Fluid-Conducting Pipe

Abstract

The present invention refers to a fluid-conducting pipe of a reciprocating compressor made of polymeric material, and further including at least one vibrational energy dissipation element, basically, aiming at solving the problem of noise and the breakage of the pipe deriving from the resonance of the discharge piping in reciprocating compressors operating at high angular speed regimes.

Claims

1. Fluid-conducting pipe of a reciprocating compressor, characterized by the fact that it is made of polymeric material, and further comprises at least one vibrational energy dissipation element.

2. Fluid-conducting pipe according to claim 1, characterized by the fact that said vibrational energy dissipation element is a spring.

3. Fluid-conducting pipe according to claim 2, characterized by the fact that said vibrational energy dissipation element has geometry: spiral with constant spire diameter and periodic segments of uniform or variable lengths with each segment section being misaligned relative to each other; or spiral with variable spire diameter along each segment with uniform or variable lengths; or spiral with constant spire diameter along its length.

4. Fluid-conducting pipe according to claim 1, characterized by the fact that said fluid-conducting pipe has the function of a discharge pipe of said reciprocating compressor.

5. Fluid-conducting pipe according to claim 1, characterized by the fact that said fluid-conducting pipe is made of polymeric material without thermoforming.

6. Fluid-conducting pipe according to claim 1, characterized by the fact that the polymeric material is selected from: Perfluoroalkoxy Alkane (PFA) and Fluorinated Ethylene and Propylene (FEP).

7. Fluid-conducting pipe according to claim 1, characterized by the fact that said reciprocating compressor comprises at least one expansion chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The preferred embodiment of the present invention is described in detail based on the listed figures, which have a merely exemplifying and non-limiting character, since adaptations and modifications may be made without thereby departing from the scope of the claimed protection.

[0020] FIG. 1 refers to a graph that demonstrates the increase of noise in reciprocating compressors at angular speeds above 4,500 rpm.

[0021] FIGS. 2 to 4 refer to a schematic view of the discharge system of a reciprocating compressor comprising the fluid-conducting pipe of the present invention with two expansion chambers.

[0022] FIG. 5 refers to a first embodiment of the fluid-conducting pipe provided with a vibrational energy dissipation element.

[0023] FIG. 6 refers to a second embodiment of the fluid-conducting pipe provided with a vibrational energy dissipation element.

[0024] FIG. 7 refers to a third embodiment of the fluid-conducting pipe provided with a vibrational energy dissipation element.

DETAILED DESCRIPTION OF THE INVENTION

[0025] As shown in the figures, the present invention refers to a fluid-conducting pipe provided with a specific construction, which allows to solve the problem of noise and/or breakage of the pipe deriving from the resonance of the discharge piping in reciprocating compressors operating at high angular speed regimes (above 4,500 rpm), economically feasible, and technically efficient.

[0026] As shown in FIG. 1, the peak of noise level generated by reciprocating compressors is characterized precisely at rotations above 4,500 rpm, so that constructions directed for this problem are highly necessary.

[0027] Thus, the fluid-conducting pipe of the present invention is preferably applicable to a discharge system of a reciprocating compressor (1) comprising a first piping portion (3), a first expansion chamber (4), a second piping portion (5), and a second expansion chamber (6). Said first piping portion (3) connects a discharge chamber (2) of the compressor (1) to the first expansion chamber 4. The second piping portion (5) connects the first expansion chamber (4) to the second expansion chamber (6). The discharge pipe (7) of the compressor connects the second expansion chamber (6) to an outlet pipe (8) of the compressor (1).

[0028] Preferably, the discharge system comprises two expansion chambers. Alternatively, the system may comprise only one expansion chamber or more than two expansion chambers.

[0029] The discharge chamber of the compressor (1), although contributing to the attenuation of dynamic pressures (pulsations), it plays a key role in the energy efficiency performance of the compressor. The piping portions and the expansion chambers are sized to attenuate the dynamic pressures deriving from the pumping of refrigerant gas in the compressor. The structure of these components can be rigid or flexible as long as it meets the requirements of mechanical strength. The discharge pipe and the outlet pipe of the compressor are sequentially connected in the last expansion chamber, and they have the function of conducting the compressed refrigerant gas out of the compressor.

[0030] The structure of such pipes is preferentially and relatively flexible to impart little vibrational energy from the inner mechanical assembly to the casing during the refrigerant gas compression process.

[0031] According to the present invention, the fluid-conducting pipe preferably acts as a discharge pipe (7), made of polymeric material. The piping made of polymeric material has lower stiffness and density, which implies a lower capacity to amplify the vibrational mechanical energy generated by the gas compression process at high angular speed of the compressor (1).

[0032] In addition, polymeric materials have higher damping compared to metallic materials traditionally used in the state of the art.

[0033] Preferably, the discharge pipe (7) made of polymeric material does not present thermoforming.

[0034] The pipe may be composed of polymeric materials, preferably Perfluoroalkoxy Alkane (PFA) and Fluorinated Ethylene and Propylene (FEP).

[0035] Furthermore, according to the present invention, the discharge pipe (7) made of polymeric material comprises at least one vibrational energy dissipation element (9) disposed on its outer surface.

[0036] This is necessary because the noise reduction produced by the discharge pipe in polymeric material is not sufficient as an attenuator for situations of reciprocating compressors operating at higher rotation regimes.

[0037] The use of the vibrational energy dissipation element (9) generates friction during vibration of the discharge pipe. This friction dissipation effect is potentiated when the radial clearances between the pipe and the spring exist and are not large. When these clearances do not exist, the dissipation is minimized; on the other hand, when the radial clearances are very large, an effect of mechanical beats is generated, which may generate unwanted noise.

[0038] Preferably, said vibrational energy dissipation element (9) is a spring arranged around said discharge pipe (7) made of polymeric material, which is more susceptible to shape variation caused by various effects, such as, alteration of the mechanical properties arising from the high temperature and aging of the polymeric material and pipe manufacturing tolerances. Therefore, the use of the polymeric pipe with the spring can generate the drawback of the greater variability of the radial clearances compared to the metallic pipes with springs.

[0039] In the context of such problems of radial clearances, in a preferred embodiment, such a spring assumes irregularly arranged spires, as shown in FIGS. 6 and 7, and it may also have regularly arranged spires, as shown in FIG. 5.

[0040] In the construction of FIG. 5, said dissipation element has a spiral geometry with constant spire diameter along its entire length. The constituent material of this element is preferably metallic, and it may alternatively be of polymeric material.

[0041] The possibility of irregular arrangement of the spires enables the radial clearances between the spring and the pipe to be adaptively controlled, since these clearances are influential in the dissipation of the vibrational energy.

[0042] In the construction of FIGS. 6, the vibrational energy dissipation element has a spiral geometry with constant spire diameter; however, the periodic segments of uniform or variable lengths have each segment section misaligned relative to each other along its length.

[0043] In the construction of FIG. 7, the spire diameters are variable along each segment, which may have uniform or non-uniform lengths. At the end of each segment, there are few spires with smaller diameters with the function of keeping the entire structure of the spring fixed in the pipe, while the other spires have larger spire diameter and may exhibit movement relative to the pipe to generate friction.

[0044] Accordingly, the construction proposed in the present invention is capable of reducing noises generated by reciprocating compressors operating at a high angular speed regime, more efficiently than the solutions described in the state of the art.

[0045] It is important to emphasize that the above description has the sole purpose of describing, in an exemplary manner, the particular embodiment of the present invention. Therefore, it is clear that modifications, variations and constructive combinations of the elements performing the same function substantially in the same manner to achieve the same results, remain within the scope of protection defined by the appended claims.