GB2128325A - Kármán's vortex street flow meter - Google Patents
Kármán's vortex street flow meter Download PDFInfo
- Publication number
- GB2128325A GB2128325A GB08227883A GB8227883A GB2128325A GB 2128325 A GB2128325 A GB 2128325A GB 08227883 A GB08227883 A GB 08227883A GB 8227883 A GB8227883 A GB 8227883A GB 2128325 A GB2128325 A GB 2128325A
- Authority
- GB
- United Kingdom
- Prior art keywords
- vortex
- kármán
- flow meter
- vortex street
- stabilizers
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
- G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
- G01F1/3209—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters using Karman vortices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
- G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
- G01F1/3209—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters using Karman vortices
- G01F1/3218—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters using Karman vortices bluff body design
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Volume Flow (AREA)
Abstract
A Kármán's vortex street flow meter comprises two conduits 26, 28 through which a fluid flows, a vortex generating element 30 disposed at a junction where the portions of the fluid flowing through the respective conduits join each other, a plurality of vortex stabilizers 32 disposed at predetermined equal intervals downstream of the vortex generating element 30, and a detector 18, 18' for detecting the frequency at which vortices 16 of a Kármán's vortex street are generated downstream of the vortex generating element to sense the flow speed or flow rate of the measured fluid. <IMAGE>
Description
SPECIFICATION Kármán's vortex street flow meter
This invention relates to a Kármán's vortex
street flow meter comprising a pair of conduit
having a measured fluid introduced thereinto, and
a detector for detecting a flow rate or flow speed
of the measured fluid by detecting a frequency at
which vortecise of a Kármán's vortex street are
generated downstream of a junction where the
measured fluid flowing through one of the
conduits joints that flowing through the other
conduit.
There have been already proposed a variety of
types of the so-called Kármán's vortex street flow
meter comprising a conduit having a measured fluid flowing therethrough, a vortex generating rod
immersed in the fluid flowing through the conduit
perpendicularly to the direction of flow of the fluid to generate a Kgrmdn's vortex street downstream of the rod and a detector for detecting a frequency
at which vortecise of the Kármán's vortex street are generated thereby to measure a flow rate or flow speed of the fluid.
Flow meters of the types referred to are disclosed and claimed, for example, in Japanese patent publication Nos. 1 905/1 969 and 9069/1981 and put to practical use as industrial measurement devices. There are also known a variety of types of sucked air detector comprising the Kármán's vortex street flow meter as described above utilized to detect an amount of air sucked into an associated internal combustion engine. Those sucked air detectors are disclosed and claimed, for example, in Japanese laid-open utility model application No. 5008/1975, Japanese laid-open patent application No.
130718/1976 and put to practical use. One of the conventional sucked air detectors has comprised a Kármán's vortex street flow meter such as disclosed above, and an air cleaner disposed upperstream of the Kármán's vortex street flow meter to clean sucked air passed through an air introduction port. Thus the sucked air introduced into the Kgrmsn's vortex street flow meter has been arranged to flow along a minimum flow path between the air introduction port and an inlet port of the Kármán's vortex street flow meter. In other words, the sucked air has flowed through the central portion of the air cleaner in the concentrated manner.As a result, only that central portion of the air cleaner has been much contaminated and also might be deformed by the stream of the sucked air.
Furthermore it has been known to use the Kármán's vortex street flow meter as described above to detect a flow rate of a measured fluid flowing in a pair of different directions through respective conduits. In the latter case the flow rate of the measured fluid has been detected either by disposing the KBrmBn'vortex street flow meter in each of the conduits or by disposing the Kármán's vortex street flow meter in a conduit foliowing a junction where the fluid portions flowing through the respective conduits have jointed each other.It
is well known that, in order to rectify the
measured fluid introduced thereinto, Kármán's vortex street flow meters are required to include a
conduit on the upstream side thereof having a
length equal to at least five times a diameter of a conduit for the same and a conduit on the downstream side thereof having a length equal to about three times that diameter. Thus the use of the Kármán's vortex street flow meters as described above have been disadvantageous in that the conduit therefor becomes long.
Accordingly it is an object of the present invention to provide a new and improved Kármán's vortex street flow meter including a vortex generating portion having a structure inexpensive, and simple as compared with the prior art practice.
It is another object of the present invention to provide a new and improved sucked air detector utilizing the Kgrmsn's vortex street flow meter as described n the preceding paragraph to detect an amount of air suckled into an internal combustion engine involved.
The present invention provides a Kármán's vortex street flow meter comprising a pair of conduits for introducing a measured fluid thereinto, a vortex generating portion disposed at a junction where portions of the measured fluid flowing through the conduits respectively joint each other, and a detector for detecting a frequency at which vortecise of a Kármán's vortex street are generated downstream of the vortex generating portion thereby to sense a flow speed or a flow rate of the measured fluid.
In a preferred embodiment of the present invention, the vortex generating portion is formed of one part of walls of the pair of conduits and a plurality of vortex stabilizers in the form of strips or rod are disposed downstream of the vortex generating portion to stabilize the generation of the vortecise downstream of the vortex generating portion.
The present invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Figure 1 is a longitudinal sectional view of a sucked air detector including a conventional Kármán's vortex street flow meter to detect an amount of air sucked into an associated internal combustion engine.
Figure 2 is a longitudinal sectional view of one embodiment according to a sucked air detector including the Kármán's vortex street flow meter of the present invention to detect an amount of air sucked into an associated internal combusion engine;
Figure 3 is a cross sectional view of the arrangement shown in Figure 2 with the section taken on the line Ill-Ill of Figure 2;
Figure 4 is a longitudinal sectional view of the arrangement shown in Figure 2 with section taken on line IV--IV of Figure 2;
Figure 5 is a longitudinal sectional view of a modification of the present invention;
Figure 6 is a view similar to Figure 5 but illustrating another modification of the present invention; and
Figure 7 is a view similar to Figure 5 but illustrating still another modification of the present invention.
Throughout the Figures like reference numerals designate the identical or corresponding components.
Referring now to Figure 1 of the drawings, there is illustrated a sucked air detector including a conventional Kgrmgn's vortex street flow meter to detect an amount of air sucked into an associated internal combustion engine. The arrangement illustrated comprises a conventional Kármán's vortex street flow meter including the main body 10 in the form of a conduit composed of a plastic material, an aluminum rectifier 12 disposed at an inlet port of the main body 10, a vortex generating rod 1 4 immersed in a measured fluids, in this case, sucked air flowing through the conduit 10 perpendicularly to the direction of flow of the fluid to generate a Kármán's vortex street 1 6 downstream thereof and a vortex detector consisting, for example, of an ultrasonic transmitter 1 8 and an ultrasonic receiver 18' disposed in opposite relationship on the wall of the conduit 10 downstream of the vortex generating rod 14 to put the Kármán's vortex street therebetween.
The main body or conduit 10 includes an inlet portion with the rectifier 14 extending into a sucked air receiver 20 of sheet iron so that the rectifier 14 opposes to an air introduction port 22 through an air cleaner 24 which, in turn, divides the receiver into a pair of compartments. The air cleaner 24 is formed of unwoven cloth.
In operation, sucked air is introduced into the receiver 24 through the air introduction port 22 and then cleaned by the air cleaner 24 after which the air is entered into the Kármán's vortex street flow meter and a flow rate thereof is measured by the vortex detector 1 8-18' in the manner well known in the art.
In the arrangement of Figure 1, the sucked air is arranged to flow along a minimum path between the air introduction port 22 and the rectifier 12 on the inlet port of the conduit 1 0. Thus the sucked air flows through the air cleaner to be concentrated on the central portion thereof. As a result, the central portion of the air cleaner 24 has been much contaminated and also may be deformed by the concentrated flow of the sucked air.
The present invention contemplates to eliminate the abovementioned disadvantages of the arrangement shown in Figure 1.
Figures 2, 3 and 4 show one embodiment according to a sucked air detector including the Kgrmsn's vortex street flow meter of the present invention to detect an amount of air sucked into an associated internal combustion engine. The arrangement illustrated comprises the Kármán's vortex street flow meter including the main body
10 in the form of a rectangular conduit having that portion thereof extending into the sucked air receiver 20 of a rectangular cross section to be forked into a pair of somewhat diverged conduit portions 26 and 28 which are, in turn, provided at the upper ends as viewed in Figure 2 with respective rectifiers 14. As in the arrangement of
Figure 1 , the rectangular conduit is formed of a plastic material.As shown in Figure 3, the conduit portions 26 and 28 have rectangular cross section substantially equal in area to each other and include the lower ends as viewed in Figure 2 merged into the main body or conduit 10 so that the adjacent walls thereof have lower ends connected to each other through a connecting wall 30 substantially perpendicular to the longitudinal axis of the conduit 10 to form a vortex generating portion. In other words, the vortex generating portion is formed of one part of the walls of the conduit portions.
Then a plurality of vortex stabilizers 32 formed of a metallic material, in this case, three stabilizers are disposed at predetermined equal intervals below the connecting wall 30 within the conduit 10, with the uppermost stabilizer spaced from the connecting wall 30 by a predetermined interval which may be equal to the predetermined equal intervals. Each of the vortex stabilizers 32 is in the form of a strip substantially equal in width to the connecting wall 30 and centered on the longitudinal axis of the conduit 10 (see Figure 2) while being suitably fixed at both ends to a pair of opposite longer walls of the conduit 10 (see
Figure 4).
In other respects the arrangement shown in
Figures 2, 3 and 4 is identical to that illustrated in
Figure 1.
When the associated internal combustion engine (not shown) is started, air sucked into the engine passes through the air introduction port 22 and then the air cleaner 24 where it is cleaned.
Then the air is rectified by the rectifiers 14 and the rectified air is introduced into the pair of conduit portions 26 and 28. When those portions of the rectified air introduced into the conduit portions 26 and 28 respectively joint each other, vortecise are generated by the vortex generating portion 30. At that time the vortex stabilizers 32 function to maintain the generation of the vortecise continuous and stable. Thus generated downstream of the lowermost vortex stabilizers 32 are periodic vortecise corresponding to a flow speed or flow rate of the sucked air resulting in the formation of a stable Kármán's vortex street 1 6.
Then the vortex detector 1 8-1 8' detects a frequency at which the vortecise of the Kgrmsn's vortex street 1 6 are generated resulting in the detection of the flow speed or flow rate of the sucked air. Thereafter the sucked air is introduced into the engine.
From the foregoing it is seen that, since the sucked air flowing through the air introduction part 22 is divided into a pair of streams thereof flowing through the conduit portions 26 and 28 respectively, the same is prevented from being concentrated at a single point upon its passage
through the air cleaner 24. Therefore the air
cleaner 24 is prevented from being locally
contaminated and also from being deformed due
to a concentrated stream of the sucked air.
Also the vortex generating portion 30 is disposed at the junction where that those portions
of the sucked air flowing through the conduit
portions 26 and 28 respectively joint each other
and vortesice are apt to be generated, so that one
part of the walls of the conduit portions 26 and 28
can be utilized as the vortex generating portion 30
resulting in a simplified structure. Furthermore the
rectangular cross section of the conduit portions 26 and 28 is effective for forming the vortex
generating portion 30 and the vortex stabilizers 32
are effective particularly with a large change in flow rate as in air sucked into an associated
internal combustion engine. That is, the flow rate
can be detected over a wide range.
Figure 5 shows a modification of the present
invention. The arrangement illustrated is different from that shown in Figures 2, 3 and 4 only in that in Figure 5 the pair of conduit portions 26 and 28 extending to be parallel to the longitudinal axis of the conduit 10.
In another modification of the present invention
illustrated in Figure 6 the pair of conduit portions 26 and 28 are curved to be gradually spaced away from- each other toward the inlet portions thereof
and the vortex stabilizer 32 is in the form of a rod
having a cross section of an inverted trapezoid.
While the single vortex-stabilizer 32 is shown in
Figure 6 only for purposes of illustration, it is to be understood that a. pluraility of vortex stabilizers 32 in the form of rods may be disposed as shown in
Figure 2, or 5.
Figure 7 shows still another modification of the - present invention. The arrangement illustrated is
different from that shown in Figure 5 only in that in
Figure 7 the pair of conduit portions 26 and 28
include their inlet portions curved to be spaced away
from each other and the connecting wall 30 has
connected thereto the uppermost one as viewed in
Figure 7 of a plurality of vortex stabilizers 32, in this
case, four stabilizers disposed in the manner as
described above in conjunction with Figure 2. That
vortex stabilizer 30 connected to the connecting
wall 30 has a width /whose ratio to the width h of
the connecting wall 30 is not less than unity (1).
This measure is effective for further stabilizing the
generation of the Kármán's vortex street 1 6. It has
been found that the width h of the connecting wall
30 greater than the width I of the vortex
stabilizers 30 results in the unstable generation of
continuous vortecise and therefore is not
desirable. All the vortex stabilizers may be
substantially equal in width to one another.
From the foregoing it is seen that the present
invention provides a Kármán's vortex street flow
meter comprising a pair of conduit portions for
introducing a measured fluid thereinto, a vortex
generating portion disposed at a junction where
those portions of the measured fluid flowing
through the pair of conduit portions respectively
joint each other and detection means disposed downstream of the vortex generating portion to detect a frequency at which vortecise of a Kgrmsn's vortex street are generated downstream of the vortex generating portion thereby to detect a flow speed or flow rate of the measured fluid.
Thus upon detecting a flow speed or flow rate of a measured fluid inflowing in a pair of different directions through respective conduit, the present invention can shorten the particular measuring conduit as compared with a conventional Kármán's vortex street flow meter or meters. Also since the vortex generating portion is disposed at the abovementioned junction where vortecise are easily generated, the resulting structure is simplified because the vortex generating portion is formed of one part of walls of the respective conduits as described above. Also the rectangular cross.section of the conduit portions 26 and 28 is effective for forming the vortex generating portion 30 as described above. In addition a plurality of vortex stabilizers 30 in the form of strips or rods are effective for detecting a flow speed or a flow rate of a measured fluid over a wide range thereof.
While the present invention has been illustrated and described in conjunction with a few preferred embodiments thereof it is to be understood that
numerous changes and modifications may be
resorted to without departing from the spirit and scope of the present invention. For example, the vortex stabilizer in the form of a rod may have any suitable cross section other than that illustrated.
Also the vortex stabilizers may be omitted with a small change in flow speed or flow rate of a
measured fluid.
Claims (8)
1. A Karman's vortex street flow meter comprising a pair of conduits for introducing a measured fluid thereinto, a vortex generating portion disposed at a junction where portions of said measured fluid flowing through said conduits respectively join each other, and a detectorfor detecting a frequency at which vortecise of a Kármán's vortex street are generated downstream of said vortex generating portion to sense a selected one of a flow speed a flow rate of said measured fluid.
2. A Kármán's vortex street flow meter as claimed in claim 1 wherein said vortex generating portion is formed of one part of walls of said pair of conduits.
3. A Kármán's vortex street flow meter as claimed in claim 1 or 2 wherein at least one vortex stabilizer is disposed downstream of said vortex generating portion to stabilize the generation of vortecise of said Karman's vortex street.
4. A Karman's vortex street flow meter as claimed in claim 3 wherein said vortex stabilizer is in the form of a strip.
5. A Kármán's vortex street flow meter as claimed in claim 3 wherein said vortex stabilizer is in the form of a rod.
6. A Kármán's vortex street flow meter as claimed in claim 1,2 or 5 wherein said pair of conduits have cross sections substantially equal in area to each other.
7. A Kármán's vortex street flow meter as claimed in claim 1, 2, 5 or 6 wherein said measured fluid comprises air sucked into an associated internal combustion engine.
8. A Kármán's vortex street flow meter as claimed in claim 1 wherein there are provided a plurality of vortex stabilizers in the form of strips to maintain the generation of said vortecise stable, so that one of said vortex stabilizers is connected to a conduit wall forming said junction while the remaining vortex stabilizers are successively disposed downstream of said vortex stabilizer connected to said conduit wall with said plurality of vortex stabilizers arranged at predetermined equal intervals, and wherein said vortex stabilizer connected to said conduit wall has a width whose ratio to a width of said conduit wall not less than unity (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08227883A GB2128325B (en) | 1982-09-30 | 1982-09-30 | Karman's vortex street flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08227883A GB2128325B (en) | 1982-09-30 | 1982-09-30 | Karman's vortex street flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2128325A true GB2128325A (en) | 1984-04-26 |
| GB2128325B GB2128325B (en) | 1986-08-06 |
Family
ID=10533265
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08227883A Expired GB2128325B (en) | 1982-09-30 | 1982-09-30 | Karman's vortex street flow meter |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2128325B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4984470A (en) * | 1986-12-02 | 1991-01-15 | Hayward Alan T J | Vortex-shedding flowmeters |
-
1982
- 1982-09-30 GB GB08227883A patent/GB2128325B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4984470A (en) * | 1986-12-02 | 1991-01-15 | Hayward Alan T J | Vortex-shedding flowmeters |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2128325B (en) | 1986-08-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4464939A (en) | Vortex flowmeter bluff body | |
| KR960014888A (en) | Heating resistance flow measurement device | |
| US5090253A (en) | Coriolis type fluid flowmeter | |
| JPH071183B2 (en) | Fluid oscillator | |
| US4478087A (en) | Karman's vortex street flow meter | |
| US6058785A (en) | Noise reduction in a mass flow measuring system | |
| GB2128325A (en) | Kármán's vortex street flow meter | |
| JP3197352B2 (en) | Vortex flow meter | |
| JP4015751B2 (en) | Differential pressure type flow meter | |
| US5908991A (en) | Karman vortex flow meter | |
| JPH0672793B2 (en) | Flow rate detector | |
| ATE117429T1 (en) | ULTRASONIC MEASUREMENT TRANSDUCER FOR DETERMINING THE FLOW AMOUNT OF A FLOWING LIQUID. | |
| JPS6127693B2 (en) | ||
| JP3192912B2 (en) | Flowmeter | |
| JPS6044607B2 (en) | vortex flow meter | |
| JPS5836018Y2 (en) | Engine intake air amount detection device | |
| JPS5821517A (en) | Sensor for karman's vortex street flow rate | |
| JPS6216655Y2 (en) | ||
| JPS61253424A (en) | Vortex flowmeter | |
| JPH04344424A (en) | Hot wire type air flow meter | |
| JPS5854671Y2 (en) | Karman vortex flowmeter | |
| JPH0599384A (en) | Bellows for fluid passage | |
| JPH08247807A (en) | Flowmeter | |
| JP3050865U (en) | Symmetric column estimation flow meter | |
| Era et al. | Concentration and velocity measurements by applying hot-wire and piezoresistive techniques |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940930 |