Stop distribution of fluid with flow independent of the pressure.

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Mouth fluid delivery rate independent of. the pressure

The present invention relates to a rotary-flow of fluid at pressure independent, one such mouth may especially be used in the traditional irrigation networks or facilities drinking water supply. to reservoirs.

In semi-arid regions, while trying to emphasize by irrigating said traditional, delivery of water from the channels to the trusses "tertiary" have often provides: the channel tertiary is implanted substantially level curve whereas the channels "quaternary", implanted perpendicularly to the tertiary, are often high pitched thus requiring coatings or works fall expensive.

Instead of quaternary channels, it is thereby leads to install pipelines which have, moreover, the advantage of a zero maintenance, advantage particularly important for ^ stem and small channels and developing important overall. Further, these pipes facilitate regulation by the downstream flow: any flow rejected by a farm remains in the channel tertiary instead of being landfilled.

Thus, for example, in the case where the duct quaternary serves several farms by hydrants connected on the ' line, strip and spaced therealong, as that a particular firm request for water, the water pressure at the inlet of a mouth may vary from 1.5 to 15m, which results in a large variation in the rate if the mouth only * is that a simple port. Therefore has been proposed mouths with variable flow area provide a constant flow rate under the conditions hereinafter.

It should be firstly that the nominal flow rate to a truss effecté can pass when the load it is to say substantially the water pressure in the conduit, is at its minimum value

* of 5m; this is what determines the maximum value of the flow area of the mouth. Then, when the load augnente, requires that the flow area decreases automatically so as to limit the flow rate to a value close to the nominal output.

Furthermore, in the facilities water supply where antennas broken out from a main pipe result in reservoirs placed head to networks and equipped with ball cocks, it frequently happens that the service operating wants to limit the flow rate drawn by each network to a maximum value, different from one network to the other. For this purpose, regulation must be the aperture stop of each float valve, but this is not sufficient because pressure upstream of each valve is variable according to the payday the main line by the other valves.

It challenge is desirable to be able to provide each float-valve a flow restriction device capable of maintaining the maximum flow rate of the tap to a constant value, regardless of the values taken by the upstream pressure. In this regard it is known to use a mouth to diaphragm applied against a fixed seat and deformable under the effect of the flow. But such a device involves a heterogeneous deformation of the material does not allow precise control of the flow rate, and is not adjustable.

Therefore it has been suggested a mouth water distribution comprising a movable nozzle secured concentrically in a stationary nozzle via a deformable sleeve of elastic material disposed between the walls of said nozzles. The movable nozzle moves under the action of the upstream pressure against a closing plate disposed opposite the end thereof within the fixed nozzle.

This mouth known is described in Patent French N^I 2, 4 54,330 (ALSTOM-TO-ATLANTIC).

It has many advantages, especially simpllcity joining, but it requires, to properly work, available deformable sleeves made of natural or synthetic rubber having good mechanical qualities constants which are difficult to obtain. Such a sleeve should indeed not only providing an elastic restoring force well determined as a function of the amplitude of the deformation, but also provide permanently effective damping oscillations which tend to occur in operation.

The present invention aims to achieve a delivery mouth to rate independent of the pressure for easily producing effective damping oscillations and stable operation over time.

It concerns a mouth 4 fluid delivery rate independent of the pressure comprising:

- a fixed support having an opening connectable to a tap hole drilled in fluid supply tubing,

- a movable nozzle extending longitudinally between an inlet end and an outlet end upstream and downstream longitudinally slidable within the aperture of the fixed support,

- a tight connection to deform and connecting the movable nozzle at stationary support so that the fluid pressure upstream pushes the movable nozzle downstream,

- and a fixed blind disposed opposite the outlet end of the movable nozzle so that when the nozzle moves downstream under the action of the pressure of the fluid upstream, this displacement decreases the section of the fluid passage between the edge of said outlet end and said valve closure member,

- this mouth being characterized in that the movable nozzle has a downstream portion located downstream of the fixed bracket and provided externally with a thrust plate rigid,

- the sealed joint between the fixed support and movable nozzle being at least partially constituted by a flexible diaphragm member extending "coupling" between the thrust plate and the fixed support, the radial distance of the movable nozzle so as to form a variable volume chamber extending radially between said nozzle and said diaphragm member and between the support and the thrust plate,

- a restricted passage being formed between this chamber and the interior of the movable nozzle so that, when the nozzle moves, the corresponding variation of the volume of the water chamber forces the fluid to pass through this passage Y undergoing a pressure drop which provides damping of the movement of the nozzle,

- of springs supported on the fixed support and acting on the thrust plate to return upstream when the fluid pressure upstream decreases.

Using schematic drawings appended thereto, we will describe below, not exclusively, how the invention may be implemented. It is to be understood that the elements described and shown may, without departing from the scope of the invention, be replaced by other elements in equivalent technical functions. When the same element is represented on several figures there is designated by the same reference signs.

Figure 1 represents a view of a mouth water distribution according to the invention in section according to the line 1 - 1 of Figure 3, the fully closed position.

Figure 2 represents a view of the same mouth, in section the same line in partially closed position under the action of water pressure.

Figure 3 represents a top view of the same mouth, baffle hood and the closure being removed.

The mouth according to the invention comprises in the known way

2 - a fixed support having an opening which can be connected to the cuff of a stitching 6 performed on a line for distributing water,

the s - a movable nozzle extending longitudinally between an inlet end upstream 10 and an outlet end downstream 12 and slidable longitudinally within the aperture of the fixed support,

14 - a deformable sealing connector connecting the movable nozzle at stationary support so that the pressure of water upstream pushes the movable nozzle downstream,

- and a fixed blind 16 disposed opposite the outlet end of the movable nozzle so that when the nozzle moves downstream under the action of the pressure of the water upstream, this movement decreases the flow area of water between the edge of said outlet end and said valve closure member.

In the example illustrated the distribution line is horizontal, and the longitudinal direction of the nozzle is vertical, the outlet being at the top. The diameter of the nozzle is e.g. 80om allowing a maximum flow rate of water when the pressure in anont 21 1/s it is to say in the pipe is of 16m of water column and a minimum rate of 19 1/s when the upstream pressure is 1, 6m. See in this example that the flow rate generated by the mouth remains constant to + 5f near and equal to 20 l/s when the pressure changes from single to ten times.

The nozzle has a circular section and the entire mouth is substantially of revolution about the axis of the nozzle.

According to the invention the operation and manufacture of this type of delivery mouth is enhanced through various arrangements indicated below:

. The movable nozzle has a downstream portion located downstream of the fixed bracket and provided externally with a thrust plate rigid. The sealing connection between the fixed support and movable nozzle is constituted by a flexible diaphragm member extending "coupling" between the thrust plate and the fixed support, the radial distance of the movable nozzle so as to provide a water chamber of variable volume extending radially between said nozzle and said diaphragm member and between the support and the thrust plate. A constricted passage is formed between the water chamber and the interior of the movable nozzle so that, when the nozzle moves, the corresponding variation of the volume of the water chamber causes water to pass through this passage Y undergoing a pressure drop which provides damping of the movement of the nozzle. Springs are supported on the fixed support and acting on the pusher plate, in cooperation with the membrane coupling, the returning upstream when the upstream water pressure decreases.

This arrangement fundamental ' will help achieve effective damping vibrations that could occur, and avoids other hand tight connection at having to provide only the return of the movable nozzle upstream pressure diminishes.

•the sealing connection between the fixed support and the movable nozzle is constituted to a flexible membrane having a first part which is fixed to the bracket adjacent the nozzle and extends radially outwardly, a second member which constitutes said connecting member and a third member returns radially towards the nozzle and is secured to the thrust plate.

The above arrangement provides a variation of the volume of the water chamber with low elastic extension (less than 10 $and preferably 5 $) of the tight connection, which is favorable for the longevity of the membrane constituting the connector.

- The constricted passage between the water chamber and the interior of the movable nozzle is constituted by a radial gap between the outer surface of the upstream end of the movable nozzle and the edge of the opening of the support.

- The edge of the opening of the support has the form of a stationary tube coaxially surrounding the upstream end of the movable nozzle. - The support carries rods extending longitudinally in a downstream direction and arranged angularly around the movable nozzle, and the springs above mentioned are coil springs surrounding said rods and compressed between the thrust plate and a rest carried by the rods.

These rods are for example three in number distributed at 120^I .

- The rods carry at their downstream end a fixed baffle hood overlying and surrounding the movable nozzle and the obturator, the obturator being carried by this cover by means of a screw passing through the hood and axial permits manual adjustment of the longitudinal position of the shutter.

This cap protects the deflection of water downwardly, while providing protection for the entire mouth.

The plug is provided with•, on its face opposite the movable nozzle, a flexible coating for a seal of the nozzle.