FR2794668A1 - Injector assembly for plant protective liquid atomising system has needle moving axially inside injector to close or open nozzle - Google Patents

Abstract

The injector assembly (15) consists of an injector (17) with a nozzle (33), and has a needle (19) which moves axially inside the injector between one position in which it closes the nozzle and a number of other positions in which it opens the nozzle aperture. The needle is connected to a mechanism which moves it axially both in the presence and in the absence of the liquid under pressure. The injector also has an injection chamber (25) bounded by the nozzle, a number of elastic membrane seals (43) through which the needle passes, and a system for introducing the liquid radially into the chamber.

Description

The present invention relates to an injector assembly for a crop protection spray system for the treatment of crops, and to a spray device equipped with this set of injector.

In some prior art spray systems, the crop liquid first passes through injection means before being sprayed.

This is particularly the case for the spraying system described in the certificate of addition No. 8217286, in which the phytosanitary liquid first passes through a hydro-injector before being sprayed onto the water. central part of a turntable.

In these spraying systems of the prior art, the circulation of the phytosanitary liquid is generally controlled by a solenoid valve located upstream of the injection means.

In addition to the fact that <B> 11 </ B> solenoid valve consumes a significant amount of electrical current, this arrangement has the effect of multiplying the number of parts needed <B> to </ B> the manufacture of these systems, and so to increase the cost, the size and the weight.

This last disadvantage is particularly troublesome in cases where it is desired to mount a large number (typically: two or three per linear meter) of these systems on a spray boom, an overweight that can cause serious malfunctions.

The main object of the present invention is to provide injection means and means for controlling the circulation of the phytosanitary liquid making it possible to overcome these drawbacks.

This object of the invention is achieved, as well as others which will appear in the following reading, with an injector assembly for a phytosanitary liquid spray system, comprising an injector provided with an injection nozzle of said liquid, characterized in that it comprises a needle movable axially in said injector between a position where it closes said nozzle and a plurality of positions where it releases the passage <B> to </ B> through said nozzle, and means for axially moving said needle in the presence as in the absence of said liquid under pressure.

According to other characteristics of this set of injector: said injector comprises an injection chamber delimited in particular by said nozzle and by sealed means traversed by said needle; and said injector comprises means for radially introducing said liquid into said injection chamber, said liquid radial introduction means in said injection chamber comprises a plurality of formed openings <B> at </ B> the periphery of this chamber and communicating with an inlet chamber surrounding said injection chamber and intended <B> to </ B> be placed in fluid communication with an inlet pipe of said liquid, < B> - </ B> said sealed means comprise at least a first elastic membrane sealingly connecting said needle <B> to </ B> the periphery of said injector, <B> - </ B> said sealed means comprise a second elastic membrane defining, with said first elastic membrane, a separation chamber communicating with the outside of said injector by at least one opening, so as to <B> to </ B> evacuate any leaks of said liquid, <B> - </ B> the area of said second membrane is equal to or greater than that of said first membrane, said first and second membranes have substantially the same area, and said separation means comprise a third elastic membrane whose area is greater than that of said first and second membranes, said sealed means comprise a substantially transverse fixed wall <B> at the axis of said injector and pierced with an axial bore through which said needle is axially movable in a sealed manner, said means for axially moving said needle comprises means for transmitting compressed air against said first (or second <B> or </ B> third) membrane, so <B> to </ B> deform and <B> to </ B> thereby move said needle, <B> - </ B> said means for axially moving said needle further comprise means for sending compressed air between said first and second membranes (or between said second and third membranes), <B> - </ B> said moving means comprise an electromechanical magnet whose core is kinematically connected to said needle, said core is connected to said needle by a lever.

Thanks to these characteristics, the injector means are combined with the means for injecting the phytosanitary liquid and the means for controlling the circulation of this liquid.

It is thus possible to reduce the number of parts, the size and the weight compared to the arrangements of the prior art.

The present invention also aims to provide a system for spraying plant protection liquid comprising injection means which is simpler, less cumbersome and lighter than those of the prior art. This object of the invention is achieved with a device for spraying phytosanitary liquid, comprising: a) a rotary plate driven by a motor, on the central part of which a nozzle projects said liquid taken by a pump into a tank, <B> b) a collector having substantially the shape of a torus sector, of defined angle, fixed to the periphery of said rotary plate without contact with it, in a manner <B> to </ b> / B> intercept the sprayed liquid in the corresponding sector, c) means for recovering this intercepted liquid, <B> d) </ B> injection means located between said pump and said nozzle and connected to said recovery means of liquid to <b> to y </ b> aspirate said intercepted liquid, and <B> to </ B> return said liquid to said nozzle with the liquid from said reservoir, characterized in that said injection means comprises a set of an injector conforming to the above.

The injector assembly according to the invention is particularly suitable for this application because it makes it possible to simplify and miniaturize a system which is, by nature, rather complex, cumbersome and cumbersome.

The present invention also aims to provide miniaturized and simplified connection means for easily connect and disconnect the aforementioned device during assembly / disassembly operations.

This object of the invention is achieved with a connection block which is remarkable in that it comprises a housing and, extending from appropriate connection elements fixed to this housing, a connection duct. supply of compressed air, a supply line liquid <B> to </ B> spray, and power cables of said engine. According to other characteristics, this connection block comprises a housing and, extending from suitable connecting members fixed on this housing, supply cables for said electromagnet, a pipe liquid supply <B> to </ B> spray, and power cables of said engine.

Thanks to these <B> </ B> features, <B> to </ B> a single small box can be reduced to all the connections required to operate the above-mentioned device, which facilitates assembly / disassembly operations. this device on the spray bars.

Other features and advantages of the present invention will become apparent from the following description and from the discussion of the accompanying drawings, in which: ## EQU1 ## <B> 1 </ B> is a front view of the device according to the invention equipped with the injector assembly according to the invention. In this figure and on the following, the injector assembly is generically represented in order to cover the various embodiments thereof; <B> - </ B> Figure 2 is a sectional view along line II-II of the device of Figure <B> 1; </ B> <B> - </ B> Figure <B> 3 </ B> is a partial sectional view along the line III-III of Figure 2 of a preferred embodiment of the injector assembly according to the invention, <B> - </ B> Figures 4 <B> to 6 </ B> are partial sectional views similar to <B> 3 </ B> other embodiments of the injector assembly according to the Invention, <B> - </ B> Figure <B> 7 </ B> is a perspective view partially broken away from the connection block according to the invention.

In these figures, the same or similar members or sets of members are designated by the same reference numerals, possibly with different indices.

In the present description, it has been chosen to present the injector assembly according to the invention when it equips a fluid spraying system that complies with the teaching of the certificate of addition FR </ B>. B> 82 17286. </ B>

While it is true that this application is particularly suitable, it must not be forgotten that the claimed protection also concerns this injector assembly per se, and that the applications of this injector assembly <B> to </ B> spraying systems other than that taught by the aforementioned certificate of addition also fall within the scope of the present application.

Referring to <B> to </ B> present in Figures <B> 1 </ B> and 2 of the accompanying drawing, in which it is seen that the spraying device according to the invention comprises first of all the following organs, described in the above-mentioned certificate of addition: <B> - </ B> a rotating plate <B> 1 </ B> driven by a motor <B> 3 </ B> preferably electric, on the central part of which a nozzle <B> 5 </ B> connected <B> to </ B> a hose <B> 7 </ B> projects liquid <B> to </ B> spray, this liquid being drawn off by a pump into a tank (not shown), <B> - </ B> a collector <B> 9 </ B> having substantially the shape of a torus sector, of determined angle, fixed <B> to </ B> the periphery of the turntable <B> 1 </ B> without contact with it, so <B> to </ B> intercept the sprayed liquid in the corresponding sector, <B> - </ B> a receptacle <B> 11 </ B> to recover this intercepted liquid, possibly equipped with a filter <B> 13, </ B> and <B> - </ B> means of injection between the said pump and the nozzle <B> 5 </ B> and connected to the receptacle <B> 11 </ B> so <B> to </ b> <B> y </ b> aspirate the intercepted liquid , and <B> to </ B> return this liquid <B> to </ B> the nozzle <B> 5 </ B> through the hose <B> 7 </ B> with the liquid from said reservoir.

Characteristically according to the invention, these injection means comprise a set of injector <B> 15, </ B> 15a, <B> 15b, </ b> 15c which several possible embodiments will be described more in detail in the following.

A preferred embodiment of this injector assembly <B> 15 is shown in FIG. <B> 3. </ B>

As can be seen in this figure, the injector assembly <B> 15 </ B> according to this embodiment comprises an injector <B> 17 to </ B> properly speaking, and a needle <B> 19 The structure and function of this needle will be explained in what follows.

The injector <B> 17 </ B> comprises a body 21 of substantially cylindrical shape, at the bottom of which is placed a member <B> 23 </ B> radially delimiting an injection chamber <B> 25. </ B >

A seal <B> 26 </ B> is interposed between the element <B> 23 </ B> and the body 21.

The injection chamber <B> 25 </ B> communicates via a plurality of openings <B> 27 </ B> with an annular groove <B> 29 </ B> formed on the periphery of a frustoconical portion < B> 31 </ B> of the <B> 23 element. </ B>

This annular groove <B> 29 </ B> forms a spray <B> liquid inlet chamber which communicates with the outside through an opening <B> 32 </ B> (see Figure <B > 1) </ B> formed on the periphery of the body 21, intended <B> to </ B> be placed in fluid communication with a conduit causing the liquid <B> to </ B> spray (see below) from the aforementioned tank (not shown).

A nozzle <B> 33 </ B> fixed for example by screwing on the element <B> 23 </ B> extends <B> to </ B> outside the body 21 in a converging cavity <B > 35 </ B> communicating with the receptacle <B> 11. </ B> A guide bearing <B> 37 </ B> extends transversely <B> to </ B> the axis <B> A </ B> the injector between the walls of the element <B> 23, </ B> <B> to </ B> near the nozzle <B> 33. </ B> This bearing is equipped with an axial orifice <B> 39 </ B> and eccentric orifices 41.

The needle <B> 19 </ B> passes through the axial orifice <B> 39, </ B> and its dimensions (diameter, length) are such that it can move in this hole between a position where it closes the nozzle <B> 33 </ B> (position shown in Figure <B> 3) </ B> and a plurality of positions where it frees the passage <B> to </ B> through this nozzle.

It should be noted that, in order to allow effective sealing of the nozzle <B> 33, </ B> it is important that the end of the needle <B> 19 </ B> has a shape corresponding as perfectly as possible <B> to </ B> that of the inside of this nozzle. It will therefore be necessary to take special care <B> to </ B> the manufacture of these parts.

In its preferred embodiment, the injector assembly according to the invention comprises at least a first resilient membrane 43 sealingly connected to the <B> 19 </ B> needle and extending to the inner periphery of the body 21.

The nozzle <B> 33 </ B> and the first elastic membrane 43 axially define the injection chamber <B> 25. </ B>

In a preferred manner, the injector assembly also comprises a second elastic membrane 45 similar to the first one and arranged parallel to it.

In the latter case, a spacer element 47 defining an intermediate chamber 49 is interposed between the two elastic membranes.

The intermediate chamber 49 communicates via at least one opening <B> 51 </ B> with an annular groove <B> 53 </ B> formed on the periphery of the element 47. This groove opens itself to the outside by at least one opening intended to remain free (not shown). A closure element <B> 55, </ B> implemented for example by screwing, maintains all of the organs described above <B> to </ B> inside the body 21. This closure element allows to compress the periphery of the two membranes 43, 45, and thus to ensure a tight connection.

The element <B> 55 </ B> further preferably comprises a threaded bore <B> 57 </ B> for connection of a compressed air line (not shown).

The needle <B> 19 </ B> is returned to <I> its </ I> shutter position by a spring <B> 59 </ B> and by the elasticity of the membranes 43 and 45.

FIG. 4 shows another embodiment of the injector assembly 15a according to the invention, only in its part that differentiates it from the previous embodiment (corresponding to zone B). of Figure <B> 3). </ B>

As can be seen in FIG. 4, a second membrane 45a is used here whose area is greater than that of the first membrane 43a, the spacer 47a and the body part 2a. between these two membranes having frustoconical shapes.

FIG. 5 shows another embodiment of the injector assembly <B> 15b </ B> according to the invention, only in its part which differentiates it from the modes of previous realization (corresponding <B> to </ B> area B of Figure <B> 3). </ B>

As can be seen in the figure <B> 5, </ B> is used here first and second membranes 43b, 45b of the same area between which is interposed a spacing element <B> 47b </ B> analog < B> to </ B> that of the figure <B> 3, </ B> and a third membrane 45b 'of greater area <B> than </ B> that of the two membranes 43b, 45b.

The spacing element 47b 'interposed between the membranes 45b and 45b' and the part of the body <B> 21b </ B> between these two membranes may have similar frustoconical shapes <B> to </ B> those of Figure 4 or more angular shapes, as shown in Figure <B> 5. </ B>

we refer <B> to </ B> present <B> to </ B> the figure <B> 6, </ B> on which is shown yet another embodiment of the injector assembly 15c according to the invention.

In what follows, the differences between this embodiment and the previous ones will be described essentially.

As can be seen in Fig. 6, the injector assembly 15c according to this embodiment includes an injector 17c <B> to </ B> properly speaking, and means <B> 61 </ B> to move a 19c needle into this injector.

The injector 17c comprises a body 21c of substantially cylindrical shape, at the bottom of which is placed an injection chamber element 23c.

The element 23c has a plurality of openings 27c formed at its periphery. At the right of these openings, the body 21c is distant from the element 23c so as to form an inlet chamber 29c surrounding this element, similar to the chamber <B> to </ B> the chamber <B > 29 </ B> described previously.

<B> A </ B> the opposite of a nozzle 33c analogous <B> to </ B> the nozzle <B> 33, </ B> the injection chamber element 23c is delimited axially by a fixed wall <B> 63 </ B> substantially transverse <B> to </ B> the axis Ac of the injector and pierced with an axial orifice <B> 65. </ B>

A closure element 55c, provided with an axial orifice <B> 69, </ B> fixed for example by screwing <B> to </ B> the inside of the body 21c, holds the injection chamber element 23c in place.

A seal <B> 71 </ B> is interposed between the element 55c and the body 21c.

The needle 19c passes through an orifice 39c formed in a bearing 37c similar to the bearing <B> 37 </ B> described above, as well as the orifices <B> 65 </ B> and <B> 69. </ B> Needle 19c play in the holes <B> 65 </ B> and <B> 69 </ B> is such that it seals against the liquid phytosanitary.

The displacement means <B> 61 </ B> of the needle 19c comprise an electromagnet <B> 73 </ B> suitably fixed <B> to </ B> the structure of the device according to the invention and whose the core <B> 75 </ B> extends in a direction substantially perpendicular <B> to </ B> that of the needle 19c.

An angled lever <B> 77 </ B> articulated around an axis <B> 79 </ B> on the body of the electromagnet <B> 73 </ B> ensures the kinematic connection between the core <B> 75 </ B> and the needle 19c. A spring <B> 81 </ B> ensures the return of this lever in the corresponding position <B> to </ B> the closing of the nozzle 33c by the needle 19c.

This lever makes it possible to reduce the overall dimensions of the injector assembly according to the invention with respect to an arrangement where the electromagnet 73 would be located in the extension. of the injector 17c.

Referring <B> to </ B> present <B> to </ B> the figure <B> 7, </ B> on which is represented the connection block according to the invention adapted to the sets of injectors Figures <B> 3 to 5. </ B>

As can be seen in this figure, this connection block comprises a housing <B> 83 </ B> and, extending <B> to </ B> from connecting female members <B> 85, 87 </ B> attached to this housing, a compressed air supply line <B> 89 </ B> and a liquid supply line <B> to spray <B> 91. </ B> >

The <B> 83 </ B> enclosure also includes <B> 93 electrical outlets from which <B> 95 electrical cables extend. </ B>

In the case where Pon wishes to use the injector assembly of the figure <B> 6, </ B> it is necessary to replace the female connection member <B> 85 </ B> and the line <B> 89 < / B> by other electrical plugs and other electrical cables (not shown). The mode of implementation and the operation of the device according to the invention derive directly from the foregoing description.

In the case where this device is equipped with the injector assembly of one of the figures <B> 3 to 5, </ B> the lines <B> 89, 91 </ B> are connected and the electric cables <B> 95 </ B> respectively <B> to </ B> the piece <B> 55 </ B> thanks to <B> to </ B> the threaded bore <B> 57, to </ B> opening <B> 32 </ B> and electric motor <B> 3 </ B> (see figure <B> 1). </ B>

In the case where this device is equipped with the injector assembly of the figure <B> 6, </ B> one connects the electric cables which replace the line <B> 89 to </ B> the electromagnet <B> 73. </ B>

Subsequently, the device according to the invention is fixed on a spray boom of agricultural machinery (not shown), and the connection pipes according to the invention are connected to the pipes and cables of the machine making it possible to feed the device according to the invention in compressed air (if any), liquid <B> to </ B> spray and current.

In operation, the liquid <B> to </ B> spray taken by the pump into the reservoir (not shown) arrives through the opening <B> 32 </ B> formed <B> to </ B> the periphery of the body 21, 21a, <B> 21b, </ b> 21c (see figure <B> 1). </ B>

This liquid then enters the inlet chamber <B> 29, </ B> 29c before penetrating radially via the openings <B> 27, </ B> 27c into the injection chamber element <B> 23 , </ B> 23c (see Figures 4 <B> to 6). </ B>

This liquid fills the volume delimited by this element, by the nozzle <B> 33, </ B> 33c and by the first elastic membrane 43, 43a, 43b (respectively, by the fixed wall <B> 63), </ B > passing through the eccentric holes 41 of the bearing <B> 37, </ B> 37c.

If the <B> 19, </ B> 19c needle closes the nozzle <B> 33, </ B> 33c, the liquid <B> to </ B> spray remains confined in the aforementioned volume: the device according to the the invention is inactive. <B> A </ B> the reverse, if the needle <B> 19, </ B> 19c releases the passage <B> to </ B> through the nozzle <B> 33, </ B> 33c, the liquid <B> to </ B> spray is injected into the converging cavity <B> 35, </ B> and then projected onto the turntable <B> 1, </ B> as indicated more top (see Figure 2).

In the embodiments of Figures <B> 3 to 5, </ B> the opening of the passage <B> to </ B> through the nozzle <B> 33 </ B> is caused by the force exerted by the liquid <B> to </ B> spray against the first resilient membrane 43, 43a, 43b, <B> to </ B> against the thrust exerted by the spring <B> 59. </ B>

According to a possible variant to open the passage <B> to </ B> through the nozzle <B> 33 </ B> without the need to send liquid phytosanitary <B> under </ B> pressure, for the modes of 4, and <B> 5, </ B> can be provided means (not shown) for sending compressed air between the first 43a and second 45b membranes (or between the second 45b and third 45b 'membranes) .

The desired opening is then obtained by the fact that the forces exerted by the compressed air on the membrane having the largest area are greater than those which it exerts on the membrane having the smallest area.

The return of the needle <B> 19 </ B> in <I> sa </ I> shutter position is ensured by the elasticity of the elastic membranes and by the spring force <B> 59 </ B> s there is no liquid under pressure in the injector.

In the case of presence of liquid under pressure in this injector, the return of the needle <B> 19 </ B> in its closed position is obtained by sending compressed air into the body 21, 21a, <B > 21b </ B> against the second elastic membrane 45, 45a (or against the third membrane 45b '), which has the effect of deforming the latter and of returning the needle <B> 19 </ B> to its initial position. It will be noted here that, in order for this return to the closed position to take place, that the pressure exerted by the air and by the spring <B> 59 </ B> on the second membrane 45, 45a (or on the third membrane 45by) is greater <B> than </ B> that exerted by the liquid <B> to </ B> spray on the first membrane 43, 43a, 43b.

It is for this reason that it is advantageous to send the compressed air on a membrane 45a, 45b 'whose area is greater than that of the membrane 43a, 43b in contact with the liquid <B> to </ B> spray: the compressed air can easily overcome the forces due to <B> </ B> the pressure of the liquid <B> to </ B> spray.

The intermediate chamber 49 (see Figure <B> 3) </ B> can be used to recover any leaks of liquid <B> to </ B> spray and to evacuate to the outside via the opening <B> 51 </ B> and the groove <B> 53. </ B> In this way, it is possible to visually detect the presence of a leak, and to prevent the liquid <B> to </ B> to spray does not reach the circuit of compressed air.

In the embodiment of Figure <B> 6, </ B> the opening of the passage <B> to </ B> through the nozzle 33c is achieved through <B> to </ B> the electromagnet <B> 73: </ B> an electrical voltage applied across its terminals has the effect of moving its core <B> 75 </ B> upwards, and thus rotating the lever <B> 77 < / B> around its axis <B> 79, </ B> which <B> to </ B> turn back the needle 19c relative <B> to </ B> the nozzle 33c.

The return of this needle to its closed position is obtained thanks to the return spring <B> 81, </ B> once the electromagnet <B> 73 </ B> has been de-energized, which 'he <B> y </ B> has or has not liquid under pressure in <b> the </ b> injector.

When the passage <B> to </ B> through the nozzle <B> 33, </ B> 33c is free, the liquid <B> to </ B> spray from the reservoir (not shown) is injected into the cavity converging <B> 35 </ B> communicating with the receptacle <B> 11. </ B> By a known effect of empty <B> pump, this injected liquid draws in the liquid which has been recovered by the receptacle <B> 11, </ B> and the mixture formed by these two fractions of different origins of the same liquid are sent to the nozzle <B> 5 </ B> by the hose <B> 7. </ B >

As can be understood <B> to </ B> present, the injector assembly according to the invention can relatively compactly meet the liquid injection means <B> to </ B> spray and the means for controlling the circulation of this liquid.

This injector assembly thus makes it possible to simplify and reduce the size and weight of the prior art arrangements, which makes it possible to envisage setting a relatively large number of devices equipped with this injector assembly on the same ramp. spraying, without the risk of malfunction.

The connection assembly according to the invention, by the simplification and miniaturization it allows, also contributes to this improvement.

Of course, the invention is not limited to the embodiments described and shown, provided <B> to </ B> illustrative and non-limiting.

Claims (1)

<U> CLAIMS </ U> <B> 1. </ B> Injector assembly <B> (15; </ B> 15a; <B> 15b; <15c) for liquid spraying system phytosanitary, comprising an injector <B> (17; </ B> 17c) equipped with an injection nozzle <B> (33; </ B> 33c) of said liquid, characterized in that it comprises a needle < B> (19; </ B> 19c) axially movable in said injector <B> (17; </ B> 17c) between a position where it closes said nozzle <B> (33; </ B> 33c) and a plurality of positions where it releases the passage <B> to </ B> through said nozzle <B> (33; </ B> 33c), and means for axially moving said needle <B> (19; </ B> 19c) in the presence as in the absence of said liquid under pressure. 2. Injector assembly <B> (15; </ B> 15a; <B> 15b; </ b> 15c) according to claim 1, characterized in that said injector <B > (17; </ B> 17c) comprises an injection chamber <B> (25) </ B> defined in particular by said nozzle <B> (33; </ B> 33c) and by sealed means (43; 43a, 43b, 63) </ B> traversed by said needle <B> (19; </ B> 19c), and in that said injector <B> (17; </ B> 17c) comprises means for radially introducing said liquid into said injection chamber. <B> 3. </ B> Injector assembly <B> (15; </ B> 15a; <B> 15b; <15c) according to claim 2, characterized in that said introducing means radial fluid in said injection chamber comprises a plurality of openings <B> (27; </ B> 27c) formed <B> to </ B> the periphery of this chamber and communicating with an inlet chamber < B> (29; </ B> 29c) surrounding said injection chamber and intended to be in fluid communication with an incoming line (91) liquid. 4. Injector assembly <B> (15; </ B> 15a; <B> 15b) </ B> according to one of claims 2 or 3, characterized in that said means at least a first resilient membrane (43; 43a; 43b) sealingly connecting said needle <B> (19) to </ B> the periphery of said injector <B> (17). </ B> <B> 5. <B> Injector assembly <B> (15; </ B> 15a; <B> 15b) </ B> according to claim 4, characterized in that said sealed means comprise a second elastic membrane (45 45a; 45b) defining, with said first elastic membrane (43; 43a; 43b) <B>, </ B> an intermediate chamber (49) communicating with the outside of said injector <B> (17) </ B> by at least one opening <B> (51), <B> to </ B> evacuate any leakage of said liquid. <B> 6. </ B> Injector assembly (15a) according to claim 5, characterized in that the area of said second membrane (45a) is equal to or larger than <B>. / B> that of said first membrane (43a). <B> 7. </ B> Injector assembly <B> (15b) </ B> according to claim 5, characterized in that said first (43b) and second (45b) membranes have substantially the same area, and in that said separating means comprise a third elastic membrane (45b ') whose area is greater than <B> than that of said first and second membranes (43b). <B> 8. </ B> Injector assembly (15c) according to one of claims 2 or <B> 3, </ B> characterized in that said sealed means comprise a wall <B> (63) < / B> fixed substantially transverse <B> to </ B> the axis (Ac) of said injector (17c) and pierced with an axial orifice <B> (65) to </ B> through which said needle (19c) can move axially tightly. <B> 9. </ B> Injector assembly <B> (15; </ B> 15a; <B> 15b) </ B> according to any one of claims 4 <B> to 7, </ Characterized in that said means for axially moving said needle <B> (19) </ B> comprises means for sending compressed air against said first (or second (45; 45a) or third (45b ') <B>) </ B> membrane, so <B> to </ B> deform and <B> to </ B> thereby move said needle <B> (19). </ B> <B> 10 An injector assembly (15a; 15b) according to claim 9 when dependent on one of the claims 6 or 7, <B> 6 </ B> Characterized in that said means for axially moving said needle <B> (19) </ B> further comprises means for sending compressed air between said first (43a) and second (45a) membranes (or between said second (45b) and third (45b ') membranes). <B> il. </ B> Injector assembly (15c) according to claim 8, characterized in that said moving means comprise an electromagnet <B> (73) </ B> > whose core <B> (75) </ B> is kinematically connected <B> to </ B> said needle (19c). Injector assembly (15c) according to claim 11, characterized in that said core (75) is connected to said needle (16). 19c) by a lever <B> (77). </ B> <B> 13. </ B> Device for spraying crop protection liquid, comprising: a) a rotatable <B> (1) </ B> driven turntable by a motor <B> (3), </ B> on the central part of which a nozzle <B> (5) </ B> projects said liquid taken by a pump into a tank, <B> b) </ B a collector <B> (9) </ B> having substantially the shape of a torus sector, of determined angle, fixed <B> to </ B> the periphery of said rotary plate <B> (1) < / B> without contact with him, so <B> to </ B> intercept the liquid sprayed in the corresponding sector, c) means <B> (11) </ B> to recover this intercepted liquid, <B> d) </ B> injection means located between said pump and said nozzle <B> (5) </ B> and connected to said liquid recovery means <B> (11) </ B> so <B > to y </ b> aspirate said li intercepted, and <B> to </ B> return this liquid to said nozzle <B> (5) </ B> with the liquid from said reservoir, characterized in that said injection means comprises an injector assembly < B> (15; </ B> 15a; <B> 15b; </ b> 15c) according to <B> to </ B> any one of the preceding claims. 14. Connection block for device <B> to </ B> Claim <B> 13 </ B> when dependent on the claim <B> 9, </ B> characterized in that it comprises a housing <B> (83) </ B> and, extending <B> to </ B> from appropriate connecting members <B> (85, 87, 93) </ B> attached to said housing, a <B> (89) </ B> compressed air supply line, a <B> (91) </ B> liquid supply line <B> to </ B> spray, and cables < B> (95) </ B> power supply of said motor <B> (3). </ B> <B> 15. </ B> Connection block for device compliant <B> to </ B> claim <B> 13 </ B> when dependent on claim <B> 11, </ B> characterized in that it comprises a housing and, extending <B> to </ B> from organs suitable connection means attached to said housing, power cables for said electromagnet (# 3), liquid supply line <B> to be sprayed, and power cables for said motor <B> (3). </ B>