CA1097275A - Full coverage recirculating sprayer - Google Patents

Abstract

ABSTRACT

A recirculating sprayer adapted for mounting on a vehicle is improved for use at increased travel speed and dor operation in higher wind conditions by angling the solid spray streams forwardly or rearwardly from a direc-tion transverse to the travel direction. The sprays are employed in criss-cross, opposite pairs, with the spray stream patterns of adjacent pairs of spray nozzles abutting or overlapping one another for full coverage of all up-standing weeds or crops in an area traversed by the sprayer.
A series of collector mats or panels may be arranged transverse to the travel direction, with sprays trained thereon for contacting each weed twice in its upstanding position once by each spray of a pair; the weeds may also be contacted once more as they are bent forward to pass beneath the panels and a reservoir thereunder. The col-lector may also be arranged in panels parallel to the travel direction for increased ease in negotiating sloping terrain. Spray liquid is collected from the collector panel(s) into reservoirs therebelow and is recirculated for reuse.

Description

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SPECIFICATION
The present invention relates to herbicid~ and/or insecticide application devices for farm crops and pastures, the devices reclaiming and reusing spray mc~terial which has not contacted target weeds or other plant rnaterial.
S Prior methods of herbicide application have lost 100% o~ all chemical material exiting a spray nozzle orifice, onto target plants, crops, and the soil. All herbicide material not actually contacting the target weed plants constitutes an economic loss, decreases weed control efficiency, and also increases concentration of herbicides in the soil and on the useful crop plants.
Recirculating sprayers have been developed within the last several years by the Delta branch Experiment Station -at Stoneville, Mississippi. The device, commercialized in 15 several forms, is substantially limited to applicatlon with ;~
row~planted crops only. Solid streams sprayed substantially transversely to the direction of sprayer travel are directed into fairly wide collector boxes. Areas beneath the collector boxes and between the spray nozzles are not traversed by any 20 herbicide sprays, leaving ribbons of untreated weeds. Also, such prior art devices are lîmited in their travel speed~
capabilities and their operating characteristics in high~er winds.
The invention is directed to a full-coverage re-ci~culating sprayer assembly for application of herbicidal and 25 other liquids via solid streams selectively to standing vegetation with recapture of liquid not con~acting the vegetation, the sprayer assembly being carried on a vehicle for .
traversing an agricultural area in a direction; the assembly comprising a source of pressurized li~uid carried on said 30 vehicle, a horizontal bar carried on said vehicle and extending 5~

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` ~3~727~i laterally o.f said direction; and ~ plurality o:E solicl-stream spray nozzles comm~micatin~ to said source o~ pressurized liquid, a collector means placed to intercept sai.d streams, and at least one reservoir loca-ted below said collec~or, all carried by said bar, and wherein the spray nozzles direct said streams at an angle to the direction of travel of at least 15, the spray noæzles are arranged in opposed pairs to provide complete, criss-cross coverage to all parts of the area traversed, said collector means comprising vertically disposed support means and collector mat means formed of a fibrous material in which liquid gravitates by capillarity flow and having a vertical orientation ~:~
with a connection at the upper end with said support means and a lower edge; and said reservoir being disposed for enclosing said lower edge of the collector mat and adapted to collect liquid flowing from the collector, said reservoir including an abutment surface spaced forwardly of the collector mat to impact against vegetation, whereby to reduce wind and travel speed effects on the solid streams of liquid and splashing of said ; ~
streams as they strike said weeds. ~ .
According to another aspect of the invention, there is~
in a recirculating sprayer assembly or application of liquid to vegetation rising above the ground~ the assembly adapted to~-be carried by a vehicle in a travel direction and comprising a plurality of spray nozzles each forming a solid stream of liquid, a collector means for intercepting the streams af~er passage among the weeds and a reservoir means for collecting unused liquid from the streams, the improvement comprising means for : aligning the spray nozzles in opposed pairs ~o create criss-cross stream patterns, the patterns contacting one another across the width of the spray assembly normal to the travel direction to assure treatment of substantially all vegetation and the streams each having an angle of at least about 15 D from the ,_ "~` , -la-, ~7~75 direction transverse -to the vehi.cle travel directioll, thereby to reduce wincl and travel speed effects on the streams, the collector means comprises a fibrous matting material extending across the entire sprayer assembly width; cmd the reservoir means encloses a lower edge of the matting material and is loca-ted at a ver-tical he:i.ght below the tops of vegetation to be sprayed.
The invention also includes the method of liquid spraying with a recirculating spray liquid for treating vegetation which includes ~he steps of directing a trea~ment liquid through a closed circuit, at one point in the circuit pressurizing the liquid to drive the liquid in the form of a stream, at a second point in the circuit throttling the pressurized stream to form criss-cross spray patterns through which vegetation under treatment may be guided,at a third point in the circuit ::
absorptively intercepting the criss-cross spray patterns with a substantially continuous fibrous collector surface to recover and filter the excess liquid not impacted against the vegetation, gravitationally and by capillarity flow directing the intercepted and recovered clarified liquid at said surface towards a reservoir receiving the lower edge of said fibrous collector surface at a fourth point in the circuit, screening the spray patterns from wind effects, and recirculating the collected filtered liquid from the reservoir back to said one point in :
the circuit.

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-lb--~ 9~2~i Figure 1 is a front slde view in perspective o~
a arm tractor with the spray assembly of the present invention mounted on the front thereof.
Figure 2 is a top plan vlew o thle sprayer assembly of -the present invention, in operation.
Figure 3 is a side eleva~ional view of the apparatus of the invention.
Figure 4 is a detail, side-sectional view taken on line IV-IV o Figure 2 Figure 5 is a top plan view, partly in section, taken on line V-V of Figure 4.
Figure 6 is a rear elevational view, partly in section, taken on line VI-VI of Figure 2. ` ;
Figure 7 is a schematic diagram of the plumbing and control systems for the sprayer assembly.
Figures 8 through 11 are top plan views, partly schematic, of sprayer assemblies employing collector panels arranged paraIlel to the dîrection of travel, and with various spray patterns and collector features.
A sprayer assembly lO is carried for traversal of an agricultural area by a tractor ll or other vehicle, as in Figure 1. The sprayer assembly lO comprises a support framework 12, a height adjustment mechanism 13, and an appIication and collector sec~tion 14. As shown in Figures 2 and 3, the support framework 12 comprises :~:

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longitudinal struts 15 which are carried by a bracket 16 connected as by means of hol-ts 17 to khe main frame of the tractor 11. The longitudinal struts 15 extend Eorwardly o~ -the tractor 11 and support there a herbi-cide tank 18 and a rearward, vertical member 19 of theheight adjustment mechanism 14. Upper stringers 20 are connected -to the rear part of the longitudinal struts 15 as shown to support same against excess bending stresses.
A bracket 21 attached to the forward part of each of the struts 15 supports the tank 18. A pair of vertically adjustable feet 22 are positioned at either end of a ~
cross member 23 affixed to the struts 15 f~r selective ~ -ground support for storage of the sprayer assembly 10 between uses.
The height adjustment mechanism 13 comprises a pair of paxallel links 25, 26 on either side of a cen-ter line of the assembly. The links 25, 26 together .
with the fixed rea~rward vertical members 19, 19 and forward members 27, 27 provide for parallel lifting of the spray applicator and`collector section 14 wlth re-spect to the tractor 11 and frame support 15. An hy-draulic cylinder 29 is remotely controllable from the tractor seat via fluid Iines 30, An actuating rod 31 of the hydraulic cylinder 29 engages and actuates the 25 ~ lower parallel lines 26 by a horizontal l~nk 32.
The spray applicator and collector section 14 in a first embodiment of the invention is constructed about a horizontal bar 35 connected to the Eront up-rights 27 of the height adjustment mechanism 13. The bar 35 is thus carried transversely to the direction of .
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travel of the tractor 11 and establishes a firm support for the spray mechaniSm 14 across its en-tire operating width. Such width may be greater for applications where fields are relatively Elat, but must be smaller where fields are more uneven.
~ Attached by means of U-bolts 36 to the horizon-tal bar 35 are a plurality of projecting spray booms 37, each attached to a plate 38 receiving the U-bolt 36 there-through. Each spray boom 37 is thus adjustable laterally ;
lU along the horizontal bar 35 to effect any selected spacing between ~hem. Carried on a front end of each bar 37 is an upstanding pin 39 connected irrotatably thereto. Each ~ `
pin 3g carries a plurality of spray nozzles 40. Each nozzle 40 creates a solid stream of li~uid 41, rather than a cone or mist of spray~ to avoid loss of liquld which would drift onto the crop and the soil.
' Each nozzle 40 is adjustable as at 42 in Figure 4 in a vertical plane Erom about 10 above the horizontal to about 30, by means o an adjustable coupling 42 be-, ~ 20 tween each nozzle 40 and a nozzle carrier plate 44 connec-~; ted to the upstanding pin 39. Adiustment of the rota~
tional position of the plate 44 is effected by means of a collar 45~ thereon engaging about the pin 39 and having a set screw 46~ Left and right side nozzle plates 44L
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; 25 and 44R have collars at opposite vertical ends thereof to avoid interfering with one another, In accordance with the invention, adjustment of the spray 41 rearwardly or : : :
forwardly Prom the direction transverse to the direction of traveI is accomplished through the arc 47, in Figure 5;
angles between about 15 and 45 from such transverse _ ~ ' .
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direc-tion have been ound most efEective. At the top of the pin 39 a shield boom 4~ is carried and is secured by means of a further set screw 49. The shield boom 48 carries at its Eorward end an angled sltield 50 having a sharp leading edge 51 for diverting taLl weeds to either side of the spray boom 37 and the components carried thereon.
The spray nozzles 40 are supplied with pres-surized herbicide or other spray fluid by means of plastic kubes 55 passing through the spray boom 37 and connecting to a distributor head 56. The head 56 is supplied with pressurized fluid from a large diameter line 57 extending forwardly to and along the horizontal bar 35.
As developed in the schematic diagram of Figure 7, the line 57 is supplied with fluid from the tank 18 through a throttling valve 58 and a filter 59 by a pump 60 driven by the tractor 11 in a c~nventional manner not shown. A
second distributor line 61 lS supplied by the pump 60 through a filter 62. The line 61 supplies a plurality of venturi suction heads 63 whlch communicate via lines 64 to the ~ottoms of collector reservoirs 70, as descri~ed below. The venturL heads 63 reduce pressure in the lines 64~ drawing collected liquid from the reservoirs 70 and into output lines 65 connecting together and leading back to the tank 18~ Because of the presence of the throttling valve 58 only in the spray line 57 r the venturi heads 63 get full ~low at all times, while the pressure and volume of flow to the spray noæzles 40 is under control of the operator of the tractor 11.
In further accordance with the principles of ~g7;~75 the present invention, the so:Lid spra~ streams ~1 are directed by the nozzles 40 -to impact upon a collector mat 68 arranged generally vertically to form an absorp-tive collector sur~ace and, in this embodiment, trans-verse to the direc-tion of movement o the tractor 11.
As shown in Figure 2, each spray 41 should intersect or overlap at least two other sprays before striking the mat 68, to assure full coverage of the ield being traversed.
Such is readily accomplished by selection of the boom 37 spacing and the rearward spray angle of the nozzles.
The collector 68 preferably comprises one or two thick~
nesses of matted, fibrous material in which liquid gravitates by capillarity flow. The liquid of the streams ~1 impacting upon the material trickles dcwn gravita-tionally and by capillarity flow through the fibrous material to a lower edge 69 of the mats 68 enclosed with- ~ ~
in the reservoir 70. Walls of the reservoir 70 closely `;
abut the mat(s) 68 to limit admission of foreign particles thereinto. The mat of fibrous material 68 also fulfills a secondary function since it tends~to operate as a fil~
ter, thereby separating contaminants and impurities so that the liquid to be recirculated is relatively clean.
The reservoir 70 is segmented along its lateral length` ~
as at 70A, so that side-to-side changes in elevation or ~ ;
attitude of the tractor ll do not cause all the collected liquid to pass to the lower end of the entire assembly.
Upper ends 71 of the mats 68 are attached together and supported by spaced vertical bars 72 connected to the `~
horizontal bar 35, where they are ad~justably retained as by further U-bolts 73. The mats 68, being substantially ' .

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~97~,75 continuous across the entire width of the spray a~semhly 14 and extending relatively far above the horizontal bar 35, shield the sprays 41 somewhat from wind.
The reservoir 70 is shown sectioned for plastic material and may conveniently compris~ a generally tubular member of polyvinyl chloride (PVC) or some similar chemi-cally resistant material, and which is slotted as at 70a to admit the fibrous mat 68. It will be understood that the reservoir 70 could be made of metal, for èxample !
stainless steel. The tubular configuration provides a surface rounded about a ~ertical axis, thereby forming an abutment surface 70b which will impact against vegeta-tion and bend it over towards the spray nozzles 40 into ~ ;
the spray pattern 41. The reservoir also prevents the ~:
vegetation from directly engaging the mat 68 of fibrous ~ :
materïal. . :
In operation, the tractor~ll with the sprayer assembly lO mounted thereon is driven through an agr~
cultural area 80 as in Piyure 3 having desired crops 81 growing thereon to a height 32. Noxious weeds 83 extend~ :
~ing above such crop height 82 may be~destroyed by spray~
ing thereon a herbicidal chemical ~rom the tank 18, The height of the spray section 14 is adjusted by the hydrau-c actuator 29 and tne~parallel links 25~ 26~ to a : 25 selected height~in ~elation to the crop height 82. The : pump 60 is actuated, sending fluid coursing through the lines 57 and 61. Throttling valve 58 supplies about ::
10 psi pressure to the dlstributor heads 56 and the sup-ply lines 55 going to the spray nozzles 40. Solid streams or ~n type streams 41 ejected from the nozzles :

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~7Z75 ~0 contact upper parts of each weed 83 erom botll left and right sides, due to the criss-cross pattern of spray of the present invention. As shown in Figure 2, the spray streams 41 cover with double sprays the entire area traversed by the sprayer assembly 10, insuring that even those weeds which are aligned with one of the spray ~-booms 37 will receive direct spray from at least one of the nozzles as it is bent to one side or other by the shield S0 and then Eorwardly by the reservoir tube 70 and bar 35. ~ ~.
; ~pray streams 41 not contacting a weed 83 will pass unobstructed to the collector mat 68 and will be collected with minimal splashing and trickle therein to the lower edge 69 thereof for collection in the reservoir `;:~:
70. ~he herbicide collected ~rom the reservoir 70 is .
passed through the suction tube 64 to the venturi 63 and back to tank 18 from the line 65. Thus, when the paths~
of the streams 41 of the spray assembly 10 are unobstruct~
ed, there will be~substantially no:loss of fluid from the .
system.
In the embodiment shown~ the spray streams 4I .;~.- :
are directed rearwardly opposite to the direction of move~
ment of the tractor 11. When the reservoir abutment sur~
face 70b bends vegetation over, the spxay nozzles 40 ~ 25 being arranged to project liyuid streams above the level :~: of the reservoir 70 ~ill spray directly into the bent :~ over vegetation. This is highly desirable ! for example, : in treating corn. Moreover, in a weeding process the ;~
rounded abutment surface 70b will not cut or break the :: -~
veyetation and thereby interfere with the action of a ~r~ ~
~111972~5 systemic chemical. An impor-tant advantacJe is created by the rearward component of velocity of t,he spray stream 41, since the net impact speed oE -the stream upon the weed material 83 will be somewhat reduced. Thus, the spray assembly of the present invention i~5 able to traverse the ground at speeds substantially double that of known prior art recirculating spray devices. Also, ; the large collector mats 68 serve to screen the sprays 41 somewhat ~rom wind, enabling the device of the present invention to operate in wind conditions up to three times that of the known prior art. Because the sprayer appara- :
tus 10 is suspended well in front of the tractor 11, dust kicked up by the wheels of the tractor cannot generally get into the herbicide system. Further, the fibrous `~ :~
matted material of the collector mats 68 filter any such ,~ dust and prevent most of it from passing through the mat to the lower end 69 thereof~and into the reservoir 70. ~-Other embodiments of the structure of the pre-sent invention are shown i.n Figures 8 through 11~ In :~
Figure 8, collector mats 168 are arranged parallel to the direction D of travel. Spray nozzles 140 mounted on each . ~' spray boom 137 each create one or more solid sprays of , liquid herbicide directed toward adjacent collection mats ,~ 168. The sprays of each pair of nozzles between each pair ...
of mats contact each other at or through the collector ., ' mats on which they are directed. Reservoirs 170 at the .
; bottoms of the mats 168 collect the ~luid as before for ~ ~
siphoning back to ~he tank. . ~.
In the apparatus of Figure 9, the spray nozzles ' 30 240 are mounted at the rear of the spray booms 137 and _ I

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~g72~s spray forwardly rather than rearwardly~ In Figure lO, -the suhstantially Elat mats have been replaced by mats 368 rounded and arranged about vertical axes, for re-ceiving sprays 341 from the rear-mounted spray nozzles 340. Finally, in Figure 11, the horizontal bar 435 is arranged at the front end of the spray apparatus, with spray nozzles 440 directing sprays 441 rearwardly.
Each of the alternate e~bodiments is useful un-der different circumstances. Having the collection mats 68 arranged parallel to the direction of travel permits the sprayer to be used on greatly-inclined surfaces, where the sidewardly-mounted reservoirs of the first em-bodiment would not be useable. In each case, the trans-verse portion of the apparatus can be closed off, so that the wind shielding ef~ects of the first embodiment can be preserved and enhanced.

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Claims (32)

1. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
   l. A full-coverage recirculating sprayer assembly for application of herbicidal and other liquids via solid streams selectively to standing vegetation with recapture of liquid not contacting the vegetation, the sprayer assembly being carried on a vehicle for traversing an agricultural area in a direction; the assembly comprising a source of pressurized liquid carried on said vehicle, a horizontal bar carried on said vehicle and extending laterally of said direction; and a plurality of solid-stream spray nozzles communicating to said source of pressurized liquid, a collector means placed to intercept said streams, and at least one reservoir located below said collector, all carried by said bar, and wherein the spray nozzles direct said streams at an angle to the direction of travel of at least 15°, the spray nozzles are arranged in opposed pairs to provide complete, criss-cross coverage to all parts of the area traversed, said collector means comprising vertically disposed support means and collector mat means formed of a fibrous material in which liquid gravitates by capillarity flow and having a vertical orientation with a connection at the upper end with said support means and a lower edge; and said reservoir being disposed for enclosing said lower edge of the collector mat and adapted to collect liquid flowing from the collector, said reservoir including an abutment surface spaced forwardly of the collector mat to impact against vegetation, whereby to reduce wind and travel speed effects on the solid streams of liquid and splashing of said streams as they strike said weeds.
2. 2. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein the sprayers direct said streams at up to about a 45° angle to the travel direction.
3. 3. A full-coverage recirculating sprayer assembly as defined in claim 11 wherein the streams are directed rearwardly of the direction of travel of the vehicle.
4. 4. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein the streams are directed forwardly of the direction of travel of the vehicle.
5. 5. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein the collector means and reservoir extend laterally of the vehicle travel direction.
6. 6. A full-coverage recirculating sprayer assembly as defined in claim 5, wherein the sprayer assembly is carried on a front part of the vehicle for first contact with vegetation as yet not passed over by said vehicle.
7. 7. A full-coverage recirculating sprayer assembly as defined in claim 6, wherein the reservoir is arranged below the height of the vegetation to be sprayed, thereby to contact said vegetation and bend at least some of them over and through at least one of said streams.
8. 8. A full-coverage recirculating sprayer assembly as defined in claim 5, wherein the reservoir is laterally segmented into compartments having no liquid communication therebetween.
9. 9. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein the collector means and the reservoir extend in the direction of travel of the vehicle.
10. 10. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein the collector means comprises a member rounded about a vertical axis and adapted and positioned to receive spray streams thereupon.
11. 11. In a recirculating sprayer assembly for application of liquid to vegetation rising above the ground, the assembly adapted to be carried by a vehicle in a travel direction and comprising a plurality of spray nozzles each forming a solid stream of liquid, a collec-tor means for intercepting the streams after passage among the weeds and a reservoir means for collecting un-used liquid from the streams, the improvement comprising:
    means for aligning the spray nozzles in opposed pairs to create criss-cross stream patterns t the patterns con-tacting one another across the width of the spray assembly normal to the travel direction to assure treat-ment of substantially all vegetation and the streams each having an angle of at least about 15° from the:
    direction transverse to the vehicle travel direction, thereby to reduce wind and travel speed effects on the streams, the collector means comprises a fibrous matting material extending across the entire sprayer assembly width; and the reservoir means encloses a lower edge of the matting material and is located at a vertical height below the tops of vegetation to be sprayed.
12. 12. In a recirculating agricultural sprayer assembly as defined in claim 11, the improvement thereof wherein the spray nozzles direct the streams rearwardly of a direction normal to the travel direction.
13. 13. In a recirculating agricultural sprayer assembly for application of liquid to vegetation, the assembly adapted to be carried by a vehicle in a travel direction and comprising a plurality of spray nozzles each forming a solid stream of liquid, a collector means for intercepting the streams after passage among the vegetation and a reservoir means for collecting unused liquid from the streams, the improvement comprising means for aligning the spray nozzles in opposed pairs to create criss-cross stream patterns, the patterns contacting one another across the width of the spray assembly normal to the travel direction to assure treatment of substantially all vegetation, and the streams each having an angle of at least about 15°
    from the direction transverse to the vehicle travel direction, thereby to reduce wind and travel speed effects on the streams, the collector means comprise a plurality of fibrous mats in which liquid gravitates by capillarity flow and arranged parallel to the travel direction of the vehicle to form vertically upright absorptive collective surfaces, at least one spray stream of each adjacent pair of nozzles contacting opposite sides of each mat, and the reservoir means having a slotted opening receiving and closely confining a lower edge of the matting materail to seal out foreign particles from said reservoir means and is located at a vertical height below the tops of vegetation to be sprayed.
14. 14. In a recirculating agricultural sprayer assembly as defined in claim 13, the improvement thereof wherein the spray nozzles direct the streams rearwardly of a direction normal to the travel direction.
15. 15. In a recirculating agricultural sprayer assembly as defined in claim 13, the improvement thereof wherein the spray nozzles direct the streams forwardly of a direction normal to the travel direction.
16. 16. A recirculating sprayer for treating vegetation adapted for use with a tractor comprising means including a mat of fibrous material in which liquid gravitates by capillarity flow and disposed to form an up-right absorbent collector and filter surface, spray means spaced from said mat and arranged to direct a spray of treatment liquid towards said absorbent surface for impact therewith, means for guiding vegetation to be treated through the spray as the sprayer is advanced so that spray not impacted against the vegetation will be recovered by impacting against said absorbent collector and filter surface with minimal splashing and will gravitate by capillarity flow in the fibrous mat towards a lower edge of said mat, a reservoir subjacent said mat and having a slotted opening receiving and closely confining the lower edge of said mat to seal out foreign particles from said reservoir means into which the recovered and filtered liquid is discharged by the mat for collection, and means to exhaust the recovered liquid from said reservoir for recirculation to said spray means.
17. 17. A recirculating sprayer as defined in claim 16 wherein there are a plurality of mats and a plurality of reservoirs.
18. 18. A recirculating sprayer as defined in claim 17 where each of said plurality of reservoirs are disposed in the direction of travel and are arranged in spaced parallel planes.
19. 19. A recirculating sprayer as defined in claim 17 where each of said plurality of mats and each of said plurality of reservoirs are disposed transversely of the direction of travel in substantially coplanar relationship with one another.
20. 20. A tractor propelled spray mechanism for treating vegetation comprising means forming a recirculating liquid circuit through which a treatment liquid is directed, a pump at one point in said circuit for pressurizing a supply of liquid and for directing the liquid in the circuit in the form of a pressurized stream, a series of booms spaced apart from one another in a line along said spray mechanism normal to the travel direction of said tractor, collector means including a plurality of fibrous mat means in which liquid gravitates by capillarity flow, each disposed on a respective boom to form a vertically upright absorptive collector surface parallel to the travel direction of the tractor and having a lower edge to which the liquid flows for discharge, said collector means defining treat-ment zones between adjacent mat means through which vegetation under treatment may be guided, a spray means at each said boom and at a second point in said circuit downstream of said first point for projecting the pressurized stream fully across each said treatment zone such that liquid not impacted against vegetation is recovered on the mat means spaced oppositely from said spray means on the other side of said treatment zone, a reservoir means dis-posed on each said boom for receiving said lower edge of a corresponding fibrous mat and into which recovered liquid is discharged by said lower edge, and means for recirculating the recovered liquid from said reservoir means to the pump.
21. 21. A recirculating sprayer as defined in claim 16, said reservoir extending transversely of the direction of travel and being disposed at a level to bend vegetation downwardly and forwardly towards the spray means as the sprayer is advanced, said spray means being disposed to spray liquid streams at a level higher than said reservoir and forwardly of said reservor to direct a spray stream rearwardly directly into the bent-over vegetation.
22. 22. A recirculating sprayer as defined in claim 21 and further characterized by said reservoir comprising a tubular component slotted to receive the edge of the mat and forming a rounded abutment surfaces for engaging vegetation extending above the level of the reservoir.
23. 33. The method of liquid spraying with a recirculating spray liquid for treating vegetation which includes the steps of directing a treatment liquid through a closed circuit, at one point in the circuit pressurizing the liquid to drive the liquid in the form of a stream, at a second point in the circuit throttling the pressurized stream to form criss-cross spray patterns through which vegetation under treatment may be guided at a third point in the circuit absorptively intercepting the criss-cross spray patterns with a substantially continuous fibrous collector surface to recover and filter the excess liquid not impacted against the vegetation, gravitationally and by capillarity flow directing the intercepted and recovered clarified liquid at said surface towards a reservoir receiving the lower edge of said fibrous collector surface at a fourth point in the circuit, screening the spray patterns from wind effects, and recirculating the collected filtered liquid from the reservoir back to said one point in the circuit.
24. 24. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein each said opposed pair of spray nozzles are disposed to direct their streams in patterns contacting one another before being intercepted by said collector means.
25. 25. A full-coverage recirculating sprayer assembly as defined in claim 1, wherein the reservoir has a slotted opening receiving and closely confining said lower edge of the collector mat to seal out foreign particles from said reservoir.
26. 26. A recirculating sprayer assembly as defined in claim 16, wherein said means including said mat is disposed to reduce wind effects on the spray of treatment liquid.
27. 27. A recirculating sprayer as defined in claim 16, wherein said reservoir includes an abutment surface spaced forwardly of said mat to impact against vegetation.
28. 28. A spray mechanism as defined in claim 20, where-in said spray means comprises plural pairs of first and second spray nozzles disposed with regard to respective booms so that the first and second nozzles of each pair are generally opposed across adjacent treatment zones to form criss-cross stream patterns therein in each zone.
29. 29. A spray mechanism as defined in claim 28, wherein said spray nozzles are disposed so that each stream pattern contacts another stream pattern in a respective treatment zone.
30. 30. A spray mechanism as defined in claim 20, where each said fibrous mat means is relatively narrow in the direction normal to the travel direction of the tractor.
31. 31. A spray mechanism as defined in claim 28, wherein said spray nozzles being mounted directly on respective booms at the forwardmost ends thereof and pointing to discharge a stream generally rearwardly and transversely in the general direction of travel.
32. 32. A spray mechansim as defined in claim 28, wherein said spray nozzles being mounted on opposite sides of respective booms immediately adjacent the rearwardmost ends thereof and pointing to discharge a stream generally forwardly and transversely in the general direction of travel.