US3434496A - Liquid spray-control device - Google Patents

Description

March 25, 1969 P L ET AL 3,434,496

LIQUID SPRAYCONTROL DEVICE Filed March 24, 1967 Sheet of 2 IN VENTORS.

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TOM/WY '0. BELL,

March 25, 1969 PHELPS ET AL 3,434,496

LIQUID SPRAY-CONTROL DEVICE Sheet Filed March 24. 1967 m m W12 2 5 pa Ed M m W it ttes US. Cl. 137-561 Claims ABSTRACT OF THE DISULOSURE A liquid-metering device to furnish pumped liquid to spray jets at a constant or at an adjustable pressure. The metering device is connected between the pump output line and the spray jets and has a return duct connected to the sump line to the liquid reservoir associated with the pump. The metering device has a relatively restricted inlet passage leading to an enlarged venturi chamber, the venturi chamber having a somewhat reduced venturi outlet passage leading to the return duct. The restricted inlet passage is parallel to, but is offset from the outlet passage to create turbulence in the enlarged venturi chamber. Another outlet passage extends laterally from the venturi chamber to the spray jet line, communicating with a portion of the tapered lower end of the enlarged venturi passage, so that the turbulent liquid partially passes through the lateral outlet passage at a substantially constant pressure. The suction in the enlarged venturi chamber may be relieved to a desired degree by the provision of an air vent. The air vent may be provided with an air filter. The amount of restriction in the air vent or filter controls the pressure of the liquid supplied to the spray jets.

This invention relates to liquid-metering devices, and more particularly to a device adapted to be employed between a liquid supply pump and a plurality of spray nozzles for delivering liquid at a constant pressure or at an adjustable pressure to the spray nozzles.

A main object of the invention is to provide a novel and improved liquid-metering device for regulating liquid supplied to spray nozzles, the device being simple in construction, being compact in size, and not involving any moving parts.

A further object of the invention is to provide an improved liquid-metering device for use in a liquid-spraying system to deliver liquid at a constant pressure or at an adjustable pressure to a plurality of spray nozzles, the device being inexpensive to fabricate, being durable in construction, providing accurate control of pressure of the liquid delivered to the spray nozzles, whereby the liquid is economically utilized, requiring a minimum amount of maintenance so that it will operate over long periods of time without attention, and being readily adjustable to provide a wide range of liquid pressures in its output circuit.

A still further object of the invention is to provide an improved liquid-metering device for use in a liquid-spraying system, the device having operational stability, having minimum susceptibility toward clogging, and being substantially self-cleaning.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE 1 is a diagrammatic view of a portion of a typical liquid-spraying system employing an improved metering device constructed in accordance with the present invention.

FIGURE 2 is a perspective view showing a feeding or metering device, as employed in the system of FIGURE 1, mounted on a hollow boom, forming part of an asatet sociated vehicle, and showing one of the associated liquid-spray nozzles and associated connecting conduits.

FIGURE 3 is an enlarged transverse vertical cross-sectional view taken substantially on the line 33 of FIG- URE 2.

FIGURE 4 is a horizontal cross-sectional View taken substantially on the line 4-4 of FIGURE 3, and

FIGURE 5 is an elevational View taken substantially on the line 55 of FIGURE 3.

Referring to the drawings, 11 generally designates a hollow boom member forming part of an associated ve hicle employed for distributing liquid in spray form, for example, insecticide, or the like. The boom 11, shown in FIGURES 2, 3 and 4, is merely typical of any suitable supporting means on the vehicle, or other apparatus, on which the device of the present invention may be mounted. Thus, in the typical embodiment illustrated in the drawings, one of the spray nozzle assemblies, shown at 12, is adjustably-supported on a bracket 13 having a post element 14- provided with a channel-shaped base 15 which is clamped to the boom 11 by means of a U-bolt 16. Suitable means are provided on the bracket 13 for adjusting the angular position of the nozzle assembly 12, for example, to an orientation such as that disclosed in FIGURE 2. The nozzle assembly 12 and its supporting bracket 13 and associated fastening structure in themselves are conventional and do not form any part of the present invention.

Designated generally at 17 is a liquid-feeding or metering device constructed in accordance with the present invention, said device comprising a main block 18 which, in the typical embodiment illustrated, is clamped to the boom 11 by a conventional generally U-shaped clamping strap 19 connected to the block 18 by a stud member 20 which is engaged through the top and bottom arms of the strap assembly 19, as shown in FIGURE 3, and which is provided with respective clamping nuts 21, 21 engaged on the top and bottom end portions of the stud 20, clamping the arms of the U-shaped strap assembly 19 to the top bottom surfaces of main block 18. The side portion of block 18 is formed with a positioning groove 22 which receives the boom 11, as shown in FIGURE 3, enabling the block 18 to be rigidly-secured to the boom by tightening the adjusting screw 23 of the strap assembly 19.

Designated at 24- is an inlet block which is secured on the top surface of the main block 18 by a pair of fastening bolts 25, 25, a generally rectangular resiliently-deformable sealing gasket 26 being interposed between the bottom surface of block 24 and the top surface of block 18, defining an interior space 27 within the gasket. Block 24 is formed with a transverse liquid-delivery passage 29. A liquid-supply conduit 30 is connected to one end of passage 29, the conduit 30 being connected to the outlet of a conventioinal liquid-supply pump 31 driven by an electric motor 32 and pumping the liquid to be sprayed, such as insecticide, or similar relatively poisonous liquid from a supply reservoir 33. An additional conduit 34 connects the other end of passage 29 to the inlet of the passage 29 of a subsequent liquid-metering assembly 17 located further along the boom 11.

The main block 18 is formed with the enlarged venturi chamber 35 whose top end is in communication with the space 27, as shown in FIGURE 3. The chamber 35 includes the frusto-conical, downwardly-convergent lower end portion 36 leading to an axial, reduced outlet passage 37. The vertical outlet passage 37, shown in FIGURE 3, leads to a transverse return passage 38 formed in the lower portion of main block 18. One end of passage 38 is connected to a return conduit 39 leading to the reservoir 33. The return conduit 40 from the next adjacent metering assembly 17 is connected to the other end of passage 38. Thus, if a series of metering units 17 are employed, their return conduits are all connected to the reservoir 33 through the transverse passages 38 provided in their blocks 18.

The inlet passage 29 in the upper block 24 communicates with the space 27 through a restricted vertical passage 46 which is substantially parallel to, but is laterallyoliset from the reduced discharge passage 37, a sis clearly shown in FIGURE 3, whereby the pumped liquid from line 30 enters the enlarged venturi chamber 35 eccentrically relative to the axis of the chamber. Thus, the jet nozzle aperture 46 receives liquid from passage 29 and directs it into the venturi chamber 35. Since the chamber 35 is considerably enlarged relative to the restricted nozzle orifice 46, considerable suction is developed in the chamber 35. This suction may be relieved by the provision of an air vent passage 47 in the upper block 24, the passage 47 communicating with the space 27, as shown in FIGURE 3. A suitable air-filter assembly 48 may be provided, the filter assembly 48 being connected to the top end of the passage 47 by a suitabl supporting conduit 49, as shown in FIGURE 3.

A downwardly and laterally-inclined outward passage '50 is provided in the main block 18, in communication with the lower portion of the generally cylindrical main venturi chamber 35 and with its frusto-conical lower end 36, as shown in FIGURE 3. Thus, the passage 50 connects with chamber 35 substantially at the junction between the cylindrical portion of chamber 35 and the frusto-conical portion 36 of said chamber, as illustrated in FIGURE 3. Passage 50 leads to a conduit fitting 51, which, in turn, is connected to a conduit 52 leading to one of the spray nozzles 12, shown in FIGURE 2. A transverse passage 53 is provided in lower block 18, communicating with the intermediate portion of passage 50, the passage 53 being employed to supply the metered liquid to additional nozzles similar to the nozzle 12 through additional conduit 52, as shown in FIGURE 1.

The restricted venturi intake passage 46 is intentionally offset from the axis of the main venturi chamber 35 and its outlet passage 37 for the purpose of causing sufficient turbulence in the lower portion of chamber 35 and the upper portion of passage 37 to cause liquid to be delivered through passage 50 at a sufficient rate to provide the desired discharge from the outlet nozzles 12. Thus, the required amount of liquid is drawn off through the passage 50, as necessary to provide the desired amount of discharge from the nozzles 12, the remaining liquid flowing through the venturi outlet passage 37 into the return passage 38 to ultimately be returned to the liquid reservoir 33.

It will be noted that the pressure of the liquid supplied in the passage 29 will aiiect both the overflow into the delivery passage 50 and the amount of suction built up in the venturi chamber 35. If the suction in chamber 35 is not relieved, then it will act on the passage 50 and prevent delivery of liquid thereto. Thus, the excess of suction must be overcome before any liquid can be drawn 01f through the passage 50. As above-mentioned, the suction can be relieved to the desired extent required by the admission of air through the vent passage 47 and through the filter assembly 48. Under certain circumstances the nozzles 12 may develop sufiicient siphon action to overcome the suction developed in the venturi chamber 35, and under these conditions the vent passage 47 may be plugged. However, if it is desired to maintain the passage 50 at substantially atmospheric pressure, the vent passage 47 is left open, with the filter assembly 48 employed to clean the incoming air. The resistance offered by the filter material, shown at 55, varies the amount of suction developed in the venturi chamber 35 from zero to a maximum value, depending upon the amount of resistance offered by the filter material. Thus, the pressure of the liquid furnished through the delivery passage '50 can be controlled by varying the amount or the nature of the filter material 55. The use of more porous material will, of course, reduce the amount of restriction to air entry and accordingly reduce the suction developed in the venturi chamber 35.

It has been found in practice that with a proper selection of delivery nozzles 12 to provide a siphon effect, as above-mentioned, combined with suitable positioning of the units 17, the nozzles 12 will operate satisfactorily with the vent passage 47 plugged. Under these conditions there is no necessity of considering the details of an air filter as above-discussed.

As above-mentioned, the vent passage 47 may be plugged when the nozzles 12 are of the siphon-type, since with such nozzles there is sufficient air intake at their rear end portions, as shown at in FIGURE 1, to relieve the suction built-up in the venturi chamber 35.

Also, as above-stated, substantially steady flow through the liquid-feeding passage 50 is provided because of the turbulence developed in the venturi chamber 35. The amount of such turbulence depends upon the degree of offsetting of the restricted venturi inlet passage 46 relative to the common axis of venturi chamber 35 and return passage 37. The amount of offset is established in accordance with the amount of turbulence required to insure steady how at the desired rate through the liquid-feeding passage 50.

It will be further noted that the liquid-feeding passage 50 is preferably at an acute angle to the common axis of the venturi chamber 35 and outlet passage 37.

While a specific embodiment of an improved liquiddistribution system for supplying liquid to spray nozzles, including an improved liquid-flow-control device, has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art.

What is claimed is:

1. In a liquid-distribution system for supplying liquid to a feed means, a pressure liquid-supply conduit, a return conduit, a delivery conduit, and a liquid flow-control device, said control device comprising a body having a liquid-supply passage connected to said liquid-supply conduit, a return passage connected to said return conduit, and a liquid-feeding passage connected to said delivery conduit, said body being formed with a relatively large venturi chamber, said liquid-feeding passage communicating laterally with one side of said venturi chamber, said body being formed with a restricted venturi intake passage connecting the liquid-supply passage to one end of the venturi chamber and with a relatively restricted venturi outlet passage connecting the opposite end of the venturi chamber to the return passage, the venturi intake passage being sufliciently oliset relative to the venturi outlet passage to produce liquid turbulence in the venturi chamber causing part of the liquid entering the venturi chamber to flow at a substantially steady rate laterally outwardly through said liquid-feeding passage.

2. The liquid-distribution system of claim 1, and wherein the venturi intake passage is substantially parallel to the venturi outlet passage.

3. The liquid-distribution system of claim 2, and wherein the venturi outlet passage is substantially coaxial with the venturi chamber.

4. The liquid-distribution system of claim 3, and wherein the venturi chamber has an end section tapering toward the venturi outlet passage, the liquid-feeding passage being located so as to intersect a portion of the tapered venturi end section.

5. The liquid-distribution system of claim 4, and wherein the axis of the liquid-feeding passage is inclined at an acute angle to the axis of the venturi outlet passage.

6. The liquid-distribution system of claim 5, and wherein said body is formed with an atmospheric vent passage communicating with said venturi chamber to relieve the vacuum developed in said venturi chamber.

7. The liquid-distribution system of claim 6, and wherein said body comprises upper and lower blocks and a fiat centrally-apertured gasket between said blocks, the central aperture of the gasket defining a space in communication with said one end of the venturi chamber and with said vent passage.

8. The liquid-distribution system of claim 7, and an air filter connected to the air intake end of said atmospheric vent passage.

9. The liquid-distribution system of claim 4, and wherein said liquid-feeding passage comprises a plurality of branches for feeding liquid to a plurality of delivery conduits.

10. The liquid-distribution system of claim 7, and wherein said upper block contains said liquid-supply passage and said lower block contains the venturi chamber, the venturi outlet passage, the return passage and the liquid-feeding passage, said upper block being formed With said restricted venturi intake passage connecting the supply passage to said one end of the venturi chamber.

References Cited UNITED STATES PATENTS 2,702,590 2/1955 Stillman 137-561 X 2,845,934 8/ 1958 Payson 137-561 X 3,334,657 8/1967 Smith et a1. 137604 M. CARY NELSON, Primary Examiner.

WILLIAM R. CLINE, Assistant Examiner.

US. Cl. X.R.

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