DE2902565A1 - Noise measurement appts. in pipes conducting rapidly flowing air - using external slit-coupled narrow tube with microphone fitting - Google Patents
Noise measurement appts. in pipes conducting rapidly flowing air - using external slit-coupled narrow tube with microphone fittingInfo
- Publication number
- DE2902565A1 DE2902565A1 DE19792902565 DE2902565A DE2902565A1 DE 2902565 A1 DE2902565 A1 DE 2902565A1 DE 19792902565 DE19792902565 DE 19792902565 DE 2902565 A DE2902565 A DE 2902565A DE 2902565 A1 DE2902565 A1 DE 2902565A1
- Authority
- DE
- Germany
- Prior art keywords
- microphone
- pipe
- measured
- noise
- flowing air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
- G01H3/10—Amplitude; Power
- G01H3/12—Amplitude; Power by electric means
Abstract
Description
Vorrichtung zur messung des Geräusches in schnellDevice for measuring the noise in quickly
durchströmten Rohrleitungen Die Erfindung betrifft eine Vorrichtung, die der Geräuschmessung in durchströmten Rohrleitungen dient.flowed through pipelines The invention relates to a device which is used to measure noise in pipelines through which there is a flow.
Die messung des in durchströmten Rohren herrschenden Geräusche ist aus zweierlei Gründen recht schwierig a) Wird die messung außerhalb des Luftstromes, d.ho vor oder hinter der Kanalmündung vorgenommen, so wird infolge der unvermeidlichen mündungsreflexion eine zu geringe Schalleistung gemessen. Allerdings läßt sich der Fehlbetrag dadurch einen Exponentialtrichter meist in ausreichendem Maße verringern.The measurement of the noise prevailing in the pipes through which there is a flow is very difficult for two reasons a) If the measurement is carried out outside of the air flow, d.ho made in front of or behind the canal mouth, as a result of the inevitable mouth reflection too low a sound power measured. However, the In this way, an exponential funnel can usually reduce the shortfall sufficiently.
mündet der Trichter aber in einen reflexionsarmen Raum, so ist das Hüllflächenverfahren anzuwenden. but if the funnel flows into an anechoic room, that is it Apply envelope surface method.
Diese methode ist aufwendig, zeitraubend und außerdem für die Ermittlung von diskreten Schallanteilen meist zu ungenau. Eine- messung im anschließenden Hallraum, die wesentlich einfacher ist, scheidet jedoch bei Vorhandensein von diskreten Schallkomponenten von vornherein aus. This method is complex, time consuming and also for the determination of discrete sound components mostly too imprecise. A measurement in the adjoining reverberation room, which is much simpler, but differs in the presence of discrete sound components right from the start.
b) Wird die messung im Innern eines Kanals vorgenommen, so besteht die Gefahr, daß allein durch das von der Strömung verursachte Windrauschen am Mikrophon eine zu große Schalleistung gemessen wird, u.Ue auch dann noch, wenn ein normaler Nasenkonus, z.Bo vom Fabrikat Brüel & Kjaer /1/, verwendet wird. Dieser Störschall, auch Pseudoschall genannt, wird durch Druckschwankungen infolge zeitlich und räumlich unregelmäßiger Wechselgeschwindigkeiten,der Eigenturbulenz der Strömung, hervorgerufen. Um die von der Rohrströmung herrührenden Druckschwankungen zu reduzieren, entwarf Friedrich /2/ ein perforiertes mit Stoff bespanntes Schutzrohr, das dem Mikrophon aufgeschoben wird. Von Neise /3/ wurde ein ähnliches, jedoch geschlitztes Vorseitzrohr entwickelt.b) If the measurement is carried out inside a duct, the result is the danger that just the wind rushing through the microphone caused by the current too high a sound power is measured, possibly even if a normal Nasal cone, e.g. made by Brüel & Kjaer / 1 /, is used. This noise Also called pseudo sound, is caused by pressure fluctuations as a result of time and space more irregular Alternating velocities, the inherent turbulence of the flow, caused. To the Friedrich designed to reduce the pressure fluctuations caused by the pipe flow / 2 / a perforated protective tube covered with fabric that is pushed onto the microphone will. Neise / 3 / developed a similar but slotted front side tube.
mikrophonvorsätze nach Friedrich und Neise sind neuer dings bei Geräuschmessungen in luftdurchströmten Kanälen vorgeschrieben /4/ und im Handel erhältlich. Diese mikrophonvorsätze sind jedoch bei Geräuschmessungen in schnell durchströmten Rohrleitungen nicht ohne Problematik anzuwenden. Besonders nachteilig wirkt sich der Einbau der verhältnismäßig dicken und langen Sonden in meßleitungen mit kleinem Rohrdurchmesser aus bzw. wird dies überhaupt unmöglich.Microphone attachments according to Friedrich and Neise are new things for noise measurements prescribed in ducts with air flow / 4 / and available in stores. These However, microphone attachments are useful for noise measurements in pipelines with rapid flow not to be used without problems. The installation of the relatively thick and long probes in measuring lines with a small pipe diameter or this becomes impossible at all.
Um die aufgeführten Nachteile zu vermeiden, wurde die auf Bild 1 dargestellte Vorrichtung entworfen, bei der sich im Gegensatz zu den Sonden nach Friedrich und Neise das mikrophon einschließlich Vorsatzrohr nicht im meßkanal, sondern außerhalb desselben befindet. Diese Vorrichtung bestsht erfindungsgemäß aus einem etwa 400 mm langen Röhrchen von etwa 6 mm lichtem Durchmesser (1), das in Richtung des LuFtstromes angeordnet und mit dem Hauptmeßkanal (2) vom Durchmesser d über einen ca. 1 mm breiten Schlitz (3), der mit einem Stoff aus Glasfassrvlies (4) oder dergleichen abgedeckt wird, verbunden ist. An seiner vorderen Stirnseite (5) ist das meßröhrchen verschlossen und mündet an seiner Rückseite (6) in ein unter ca. 150 abgewinkeltes Adapterstück (7) zur Aufnahme des mikrophones (8).In order to avoid the disadvantages listed, the one shown in Figure 1 was made Device designed in which, in contrast to the probes according to Friedrich and Move the microphone, including the attachment tube, not in the measuring channel, but outside the same is located. According to the invention, this device consists of approximately 400 units mm long tube with an internal diameter of about 6 mm (1), which runs in the direction of the air flow arranged and with the main measuring channel (2) of diameter d over a 1 mm wide Slot (3) covered with a fabric made of Glasfassrvlies (4) or the like is connected. The measuring tube is closed on its front face (5) and opens on its rear side (6) in an adapter piece angled at about 150 (7) to hold the microphone (8).
Diese Sonde hat gegenüber allen anderen Gerbuschmeßsonden den Vorteil, daß das mikrophon leicht zugänglich ist, was das Kalibrieren erleichtert und keine besondere Halterung erfordert, die ihrerseits wieder Strömungsverwirbelungen und damit Störschall auslöst. Auch werden die Zu- und Abströmbedingungen von in Rohre eingebauten und zu messenden Apparaturen nicht im geringsten behinderte Ein besonderer Vorteil ist, daß mit der Sonde gemäß Erfindung sslbst in solchen Rohren einwandfreie Schallmessungen möglich geworden sind, deren Durchmesser kleiner als der mikrophondurchmesser ist.This probe has the advantage over all other Gerbusch measuring probes, that the microphone is easily accessible, which makes calibration easier and none requires special bracket, which in turn again flow turbulence and so that noise triggers. The inflow and outflow conditions of in pipes built-in and measuring devices not in the least handicapped a special one The advantage is that with the probe according to the invention ssl even in such pipes Sound measurements have become possible whose diameter is smaller than the microphone diameter is.
Literatur /1/ Brüel & Kjaer-Katalog, Verlag K. Larsen & Sohn, Lyngby, Dänemark, 1963 /2/ Friedrich, J.: Ein quasischallunempfindliches Mikrofon für Geräuschmessungen in turbulenten Luftströmungen. Techn. mitt. RFZ 11 (1967) /3/ Neise, W.: Einfluß der mikrofonströmung bei der messung von Ventilatorgeräusch im angeschlossenen Kanal DLR-FB 74-04 /4/ DIN 45 635, Teil 9.Literature / 1 / Brüel & Kjaer catalog, Verlag K. Larsen & Sohn, Lyngby, Denmark, 1963/2 / Friedrich, J .: A quasi-sound-insensitive microphone for noise measurements in turbulent air currents. Techn. RFZ 11 (1967) / 3 / Neise, W .: Influence of the microphone flow when measuring fan noise in the connected channel DLR-FB 74-04 / 4 / DIN 45 635, part 9.
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19792902565 DE2902565A1 (en) | 1979-01-24 | 1979-01-24 | Noise measurement appts. in pipes conducting rapidly flowing air - using external slit-coupled narrow tube with microphone fitting |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19792902565 DE2902565A1 (en) | 1979-01-24 | 1979-01-24 | Noise measurement appts. in pipes conducting rapidly flowing air - using external slit-coupled narrow tube with microphone fitting |
Publications (1)
Publication Number | Publication Date |
---|---|
DE2902565A1 true DE2902565A1 (en) | 1980-08-07 |
Family
ID=6061249
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19792902565 Withdrawn DE2902565A1 (en) | 1979-01-24 | 1979-01-24 | Noise measurement appts. in pipes conducting rapidly flowing air - using external slit-coupled narrow tube with microphone fitting |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE2902565A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0108556A2 (en) * | 1982-11-05 | 1984-05-16 | Lintvalve Electronic Systems Limited | Apparatus for detecting leaks in steam raising boilers |
DE3819398A1 (en) * | 1987-07-16 | 1989-01-26 | Deutsch Franz Forsch Inst | Acoustic pressure pick-up insensitive to wind influences |
FR2764694A1 (en) * | 1997-06-17 | 1998-12-18 | Aerospatiale | DEVICE FOR MEASURING NOISE IN A CONDUIT BROUGHT BY A FLUID |
-
1979
- 1979-01-24 DE DE19792902565 patent/DE2902565A1/en not_active Withdrawn
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0108556A2 (en) * | 1982-11-05 | 1984-05-16 | Lintvalve Electronic Systems Limited | Apparatus for detecting leaks in steam raising boilers |
EP0108556A3 (en) * | 1982-11-05 | 1985-07-10 | Lintvalve Electronic Syst Ltd | Apparatus for detecting leaks in steam raising boilers |
DE3819398A1 (en) * | 1987-07-16 | 1989-01-26 | Deutsch Franz Forsch Inst | Acoustic pressure pick-up insensitive to wind influences |
FR2764694A1 (en) * | 1997-06-17 | 1998-12-18 | Aerospatiale | DEVICE FOR MEASURING NOISE IN A CONDUIT BROUGHT BY A FLUID |
EP0886131A1 (en) * | 1997-06-17 | 1998-12-23 | AEROSPATIALE Société Nationale Industrielle | Device for measuring noise in a fluid-carrying pipe |
US5925821A (en) * | 1997-06-17 | 1999-07-20 | Societe National Industrielle | Device for measuring noise in a pipe traversed by a fluid |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
8139 | Disposal/non-payment of the annual fee |