Acoustics – Sound-modifying means – Muffler – fluid conducting type
Reexamination Certificate
2000-02-28
2001-10-16
Nappi, Robert E. (Department: 2837)
Acoustics
Sound-modifying means
Muffler, fluid conducting type
C181S252000
Reexamination Certificate
active
06302236
ABSTRACT:
The present invention relates generally to a pulsation damper and more specifically to a pulsation damper having a diffuser.
A damper of this kind is known from U.S. Pat. No. 5,563,382 and serves to damp gas pulses with a frequency of less than 100 Hz and preferably between 10 and 20 Hz. In doing so, it is necessary to satisfy the requirements of various standards, of which the API standard is the most important. This standard prescribes that the peak-to-peak pulsation with respect to the average absolute pressure is never more than 2% of the average sound level.
On the other hand, of course, it is prescribed that the pressure loss through a damper of this nature is as low as possible. For a low-pressure system which operates, for example, between 2 and 3 bar, this means that a maximum pressure loss of 15-20 millibar is permissible.
Currently, the market is demanding an ever increasing improvement in the silencing action, i.e. that the average sound level be limited to an ever greater extent. This results, on the one hand, from the wish to cause less environmental pollution and, on the other hand, from the mechanical load which is caused by pressure pulses in devices which are connected downstream of the sound absorber.
Moreover, it is required that large sound absorbers should have a particularly long service life, i.e. should function for at least five years without maintenance. Since dampers of this kind are produced from standard steel grades, corrosion and the like play an important role. It is also important that in the event of possible damage caused by long-term load the damaged components should be easy to replace.
The object of the present invention is to provide a pulsation damper which has improved damping characteristics without its design being complicated to any significant extent. Another object of the invention is to increase the service life of diffuser pipes of this nature. One way of damping sound waves is to arrange a diffuser either in the inlet or in the outlet. In the prior art, a diffuser of this nature comprises a pipe-like part which is provided with a perforation. In this case, the total surface area of the free passage of the perforations is at least equal to the total inlet or outlet surface.
REFERENCES:
patent: 3957133 (1976-05-01), Johnson
patent: 4011922 (1977-03-01), Goplen
patent: 5365025 (1994-11-01), Kraai et al.
patent: 5563382 (1996-10-01), Choyce
patent: 6082487 (2000-07-01), Angelo et al.
patent: 6109387 (2000-08-01), Boretti
patent: 6155379 (2000-12-01), Nakagawa
patent: 475398 A1 (1992-03-01), None
patent: 08/114110 (1996-05-01), None
Database WPI, Week 901415 Sep. 1989, Derwent Publications Ltd., London, GB, AN 90-105822, XP002064184, and SU 1 507 997 A (Armn Hygiene Inst.) Sep. 15, 1989.
Fitch Even Tabin & Flannery
Lockett Kim
Nappi Robert E.
Q.E. International B.V.
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