FR2583118A1 - Energy-dissipating device with baffles and cavities having a swirling effect - Google Patents

Abstract

The invention relates to a device for dissipating the energy of a fluid, consisting of a channel equipped with walls and baffles of specific shapes, thus creating cavities where the flow becomes swirling. The channel is formed by walls 11, baffles 5 the concavity 12 or facet 7 of which sends the flow backwards and closes the swirling cavity 10. The energy is dissipated in the swirl and part of the flow passes from one cavity to the next. The favoured field of the application of the invention is drop-by-drop irrigation for flow rate limiters.

Description

The present invention relates to dis- sitlfs baffles placed in the channels and conduits for transferring fluids and intended to slow the flow of fluid by dissipation of its kinetic energy.

There are already baffle channels which create successive and generally alternate angular deviations.

The device according to the invention consists of successive cavities aéli ités by baffles and communicating with each other. Each cavity is the seat of a vortex, and the arrangement of the baffles is such that the successive vortices have opposite directions of rotation. It is mainly the specific shape of the baffles, which, acting on the current of fluid, puts it in vortex -lonnary rotation, the baffles have indeed a concave part which returns the fluid to the "back", the deflection angular of this part being greater than 1800. Part of the "returned" fluid forms the vortex, another part feeds the next cavity. The latter being "nested" over the previous one.

The shapes of the cavities and baffles are such that there are no dead zones where deposits of particles contained in the fluid could clump together.

Three drawing plates make it possible to specify the description of the invention:
- Figures 1 and 2 are sections of baffle channels to
alternating flows.

- Figures 3 to 10 are sections of the baffle channels and
swirl cavities according to the invention.

- Figures 11 to 18 relate to applications of the invention
in heat sinks or flow limiters.

 - Figure 11 is a section of a flow limiter.

- Figure 12 is a developed view of the cylinder carrying the channel
with baffles according to the invention, of the flow limiter of the
figure 11.

 - Figure 15 is a section through another flow limiter.

- Figure 14 is a developed view of the 2 active parts
the cylinder carrying the baffle channel according to the invention,
of the flow restrictor in figure 13.

- Figure 15 is a section of a flow limiter where the
bearing part of the baffles is conical.

- Figure 16 is a section of a flow limiter where the
active part consists of the 2 parallel faces of a
pastille.

- Figure 17 is a plan view of one of the faces of the
pellet fitted with a baffle channel, flow limiter
in Figure 16.

- Figure 18 is a sectional view of a flow limiter
self-regulating comprising a crown carrying a channel
with baffles according to the invention.

te channel presented siar the fugure 1 is provided with straight baffles 1 and 2, with parallel faces and straight ends 1 l in rounded 2. At each baffle the fluid undergoes a change of direction less than 180.

The channel presented in FIG. 2 is provided with baffles 3 and 4 called conical or trapezoidal, the faces of which form a dihedral, and the ends are flat 3 rounded 4. At each baffle the fluid undergoes a change of direction significantly less than 180, according to the arrows.

The channel shown in Figure 3 is provided with baffles 5 according to the invention. The baffle 5 consists of an inclined part 6 in the direction of the flow, a second inclined part 7 in the direction opposite to the average flow, a flat nettle 8 along the axis of the channel, and an inclined #part 9 on the back of the baffle. The cavities 10 are delimited by the planes 6,7 of a c '; iicane, the plane 8 of an opposite baffle, the plane 9 of another adjacent baffle and by a wall 11 of the channel. The orientations of the baffle faces and the planes of the cavities 10 are such that inside each cavity 10 a vortex is formed which fills the cavity. Part of the vortex escapes and feeds the vortex of the cavity neighbor.

this part of the vortex must break its moment of rotation to turn in the other direction, there is dissipation of energy. The turbulent vortices there is dissipation of energy in the core of the vortex by internal friction; moreover the other walls delimiting the channel are substantially parallel and "flat", the vortices rub on these walls and lose kinetic energy. For sections of canal colpar-ble according to Figures 1 - 2 and 3, in the case of Figure 3, the part of the section used for the transfer from one cavity to another is small and therefore requires a larger speed to pass ur same flow; the dissipation of kinetic energy by cavity or by baffle will be for compa -rable channels, significantly higher with baffles according to the invention.

In addition, all the surfaces of the baffles are swept by high-speed currents, which prevents deposits in the case of irrigation water.

Figure 4 shows a variant of the baffles of Figure 3, the facets being replaced by rounded profiles. The
the facets 6 and 7 are replaced by the # cavity 12 and the facets 8 and 9 by the convexity 13 and the concave connection 14.

Figure 4 shows another variant of the baffles and cavities of the channel. The concavity 12 is maintained. Facet 8 is replaced by a slightly domed facet 15, and facet 9
conest replaced by a # cavity 16.

 Figure 6 shows a variant of the embodiment according to Figure 4. The baffles are the same, the walls 11 of the channel are more distant and the cavities 10 are wider.

 Figure 7 shows a variant of the embodiment according to Figure 5. The concavity 12 is maintained, the facets 15 are more flat and the concavity 16 less pronounced.

 Figure 8 shows another variant of baffles and cavities according to the invention. The baffles are symmetrical. The concavities 12 and 16 are the same and opposite, the facet 15 is in concavity so as to promote the vortex in the cavity 10.

 Figure 9 shows baffles according to Figure 8 and shows other forms of symmetrical baffles, the central facets being concave 17, flat 18 or connected 19. This figure shows some geometric sizes of the channel, baffles and cavities.

. H is the maximum width of implantation of the canal
. A is widen ## from the canal to the right of the chicane, or
cavity width
. <H - A) is the height of the baffle
. B is the width of passage between two alternating baffles
. P is not the baffles
. Pr not shown, the depth of the channel
. Q the width of the vortex fluid
The best performances have been obtained for a given overall size when the values of 1, B; (E - A) and Pr abXt neighbors.

 FIG. 10 presents alternative arrangements of baffles, such that the width s is considered to be zero. The flow along arrow 20 at the periphery of the vortex abuts on the back of the previous baffle and stops. The flow according to arrow 21 abuts on the stop of the previous baffle and the turn-ball remains theoretically closed. In fact in these two cases there is still an escape of fluid from one cavity to the next under the effect of the pressure gradient.

 Figures 11 to 18 show the adaptation of baffles and tcurbillonnaires cavities according to the invention to different types of flow restrictors or drippers for irrigation.

 Figure 11 shows a very simple dripper in two pieces co !: taking a body 21 which mounts in bypass on a pipe through a nozzle 22 in the shape of a viper head. The second part 23 of cylindrical shape slides hard in the body 21. The cylindrical exterior carries the channel with the baffles. This part is re-reserved develozDée on Ligure 12. The axis lines 24 and 25 represent the planes of joint of the part obtained by pressure molding of plastic materials. The water enters at 26 passes in the channel made up of baffles 27 and cavities 28; the passge of the parting line is done by a channel 29. when the channel has lasted almost a full turn it makes a half-turn without crossing the parting line and returns parallel to the first channel.

The exit takes 30 outside. The embodiment presented comprises a channel consisting of a circular outward and return path. To adapt to the pressure to be dissipated or to the chosen flow rate, it is possible to modify the dimensions of the baffles and channels or to increase the number of circular round trips.

The outlet 30 of FIG. 12 transforms into a half-turn and is pushed back at the end of an additional or multiple outward or return journey.

 Figure 13 shows an in-line dripper, which connects two pipe sections. it consists of a female body 31, smooth on the inside in which comes the male stud 32 carrying the baffles and cavities according to the invention. The parts in contact are cylindrical or very slightly conical to give better tightening. The dripper fits onto the ends of the pipe by its grooved ends 33. The channel formed by baffles and cavities could consist of a large number of circular round trips presented in FIG. 12. Figure 14 shows another arrangement of the channel, where the number of crossing the joint plane is reduced to once. FIG. 14 shows the 2 opposite faces of the cylinder carrying the channel with the baffles. The water enters at 34, and describes a circular channel extending over less than a semicircle 35; instead of joining the joint plane the channel makes a U-turn and describes another portion of semi-circle 36; again he makes a U-turn and so on. At the end of the last semicircle portion 37, the fluid returns to the channel 38 along the generatrix adjacent to the joint plane. The fluid crosses the joint plane at 39 and is found on the other "face" of the cylinder.

After a succession of de-i-circles carrying baffles and cavities, the fluid leaves in 40j holes in the circular grooves L1 allow the fluid to exit to the outside.

 Figure 15 shows a flow rate in 3 parts. It includes a base 51, - equipped with a water intake pricking on a pipe, a conical cap 52 screwing onto the base 51 and a conical stud 53 carrying the channel with baffles and cavities according to the invention, the outer conical surface of 53 being pressed against the inner conical surface of 52 under the effect of pressure. A pusher 54 makes it possible to separate the 2 parts 52 and 53 for washing by rapid flow or "flushing" of any deposits.

This device was essential for the old drippers where the channel consisted of a laminar flow spiral. The arrangement of the baffles and the cavities on the external conical surface of 53 is either an extension of aa FIG. 12 to several circular round trips and makes a conical adaptation of the 2 "faces" of FIG. 14.

 FIGS. 16 and 17 relate to a button-shaped flow limiter consisting of a body 61 fitted with a water intake pricking on a pipe, of a cover 62 ~ closing the corpB 61- by clipping, the body and the cover having two faces looking at each other parallel, inside a pellet 63 carries on its 2 faces a channel consisting of baffles and cavities according to the invention.

The clipping of the cover 62 is such that the pellet 63 is sealed between the body 61 and the cover 62. The fluid arrives through the center, enters the circular channel and passes through the pellet at the end of the channel on the first face, by an orifice 64, then again describes a circular channel consisting of baffles and cavities according to the invention, then comes out through the center.

Figure 18 shows a self-regulating flow limiter fitted
cavities and baffles according to the invention. This limiter is
consisting of a body 71 provided with a water intake pricking on a
pipe, and of a cover 72 which is fixed by screwing or clipping
on the body 71. An elastic membrane 73 is pinched between the
body and cover, it is fitted with a port 74, feed
-as a circular groove 75 located in the cover 72. The
cover is fitted with a circular channel 76 consisting of cavities
and baffles according to the invention.

This channel, the end and end of which are delimited by the same radial partition, is supplied by an orifice connected to the distribution groove 75, and has a racial outlet towards the chamber 77 equipped with a central exhaust orifice 78 communicating with the exterior or # - use of the fluid. The pressure of the fluid entering through the body pushes the membrane 73 against the cover 72, the membrane thus constituting the last face of the channel. The fluid passes through the orifice 74 with a small pressure drop then in the channel 76 with a larger pressure drop and arrives in the chamber 77 with a pressure lower than the inlet pressure. Geometric characteristics in channel and mechanical of the membrane are such that for a given pressure difference the membrane is flush with the outlet orifice 78.

This pressure difference corresponds to a flow in the channel according to the invention. If the pressure increases, the membrane gets even closer to the orifice, decreases its outlet section and creates an additional pressure drop which compensates for the pressure increase;
The flow remains stable. Self-regulating flow limiters were the subject of an invention by the company CITROEN, an invention that fell into the public domain. The restrictor was reduced to the orifice in the membrane, whereas in the present case it consists of the orifice in the membrane and of a channel consisting of baffles and cavities according to the invention.

 The main field of application of the invention is microirrigation or drip irrigation. The invention also applies to hydraulic and pneumatic applications to limit d-bits and dissipate kinetic energy or pressure energy.

Claims (9)

E V E N D i C A T i O N S  1) Dis # ositif energy dissipator of a fluid flow consisting of baffles 5 and channel walls 11 forming cavities 10 alternately succeeding each other, the faces c - 7 and 12 of the baffles receiving the fluid, returning it to the 'rear so as to generate vortices in the cavities 10, the successive vortices having their alternating directions of rotation.  2) Device according to claim 1, wherein the baffles 5 are faceted 5 - 7 - 8 - 9, a facet 8 returning the flow backwards.  3) Device according to claim 1 wherein the baffles 5 have their cesd'abord concave face 12, then connected 13 and concave 14, the concave face 12 returning the flow to  4) Device according to claim 1 wherein the baffles 5 have two opposite faces concavec 12 and 16 and a flat domed central face. or concave.  5) Device according to claim 4 or the baffles are sequential -  6) Flow restrictor equipped with an energy dissipating device according to any one of claims 1 to 5 wherein the channel equipped with baffles 5 is formed of circular arcs distributed over a cylinder or a trunk of cone.  7) Flow restrictor equipped with an energy dissipating device according to any one of claims 1 to 5 wherein the channel equipped with baffles 5 is formed by arcs of circles distributed on the faces of a pellet.  8) Flow restrictor equipped with an energy dissipating device according to any one of claims 1 to 5 or the channel equipped with baffles 5 is formed by an arc of a circle and is delimited by an elastic membrane applied by pressure and moreover ensuring pressure ragulation between the inlet and the outlet of the restrictor 10 energy dissipator made up of cavities and baffles 5.  9) Flow restrictor equipped with energy dissipator according to any one of claims 1 to 8