Nozzle for spraying liquid polymer preparations and spraying method utilising the nozzle

Abstract

A method for spraying a mixture comprising at least a first liquid in the form of a liquid preparation of water-soluble or water-swellable polymers and at least a second liquid, characterized in that it implements a nozzle for simultaneously spraying at least two liquids, comprising: •a body provided with a first chamber within which a first liquid flows and a second chamber within which a second liquid flows, each of the two chambers having a through-hole on the outside of the body, •a deflector secured to the body arranged downstream from at least one of the through-holes, in the direction of flow of the first and second liquids, said deflector being capable of modifying the direction of flow of the first and second liquids. The invention also relates to a nozzle for implementing the method.

Claims

1. A method for spraying a mixture comprising at least a first liquid in the form of a liquid preparation of water-soluble or water-swellable polymers and at least a second liquid, wherein said method comprises implementing a nozzle for simultaneously spraying at least the first liquid and the second liquid, the nozzle including: a body provided with a first chamber within which the first liquid flows and a second chamber within which the second liquid flows, each of the two chambers having a through-hole on the outside of the body, wherein the first chamber and the second chamber form a truncated cone shape having a tapered portion upstream of the through-holes, and wherein within the truncated cone shape, the first chamber and the second chamber are positioned concentrically in relation to one another, such that the first liquid and the second liquid flow concentrically relative to one another as they approach the through-holes, and a deflector secured to the body arranged downstream from at least one of the through-holes, in the direction of flow of the first and second liquids, said deflector being capable of modifying the direction of flow of the first and second liquids, wherein: the through-holes are aligned on the same plane on the outside of the body and are positioned concentrically in relation to one another such that the first and second liquids mix at the latest when they come into contact with the deflector; and the deflector assumes the form of a cone of revolution wherein the apex thereof is oriented towards the through-holes and wherein the axis of the deflector is combined with the axis of said holes.

2. The method for spraying according to claim 1, wherein the axis of one of the through-holes is positioned in the longitudinal direction of the body.

3. The method for spraying according to claim 2, wherein the deflector is positioned downstream from the through-hole having the axis that is positioned in the longitudinal direction of the body.

4. The method for spraying according to claim 1, wherein the second liquid is aqueous or organic or a mixture of the two.

5. The method for spraying according to claim 1, wherein the second liquid assumes the form of a water in oil emulsion or the form of an aqueous dispersion of particles.

6. The method for spraying according to claim 1, wherein the second liquid contains at least one substance of agronomic interest or at least one substance making it possible to improve the development or the growth of plant material.

7. The method for spraying according to claim 1, wherein the second liquid contains at least one cross-linking agent.

8. The method for spraying according to claim 1, wherein the first liquid comprises an acrylamide copolymer.

9. The method for spraying according to claim 1, wherein the weight content of polymer in the first liquid is between 0.01% and 75%.

10. The method for spraying according to claim 1, wherein the method is implemented in a fields of agriculture.

11. The method for spraying according to claim 9, wherein the weight content of polymer in the first liquid is between 5 and 60%.

12. The method for spraying according to claim 9, wherein the weight content of polymer in the first liquid is between 10 and 50%.

13. The method for spraying according to claim 1, wherein the method is performed in order to limit soil erosion, treat rainwater or wastewater, as part of a paper making process, or during mining extraction.

14. The method for spraying according to claim 1, wherein: the axes of the through-holes are secant such that the first and second liquids mix before they come into contact with the deflector; and/or the axis of one of the through-holes is positioned in the longitudinal direction of the body, and the deflector is positioned downstream from the hole having the axis that is positioned in the longitudinal direction of the body.

15. The method for spraying according to claim 1, wherein chambers present in the body consist of the first chamber and the second chamber.

Description

(1) The invention and resulting benefits will become clear from the following examples, supported by the attached figures.

(2) FIG. 1 describes a preferred embodiment of the nozzle according to the invention for which the body of the nozzle 1 comprises two chambers 2 and 3 opening onto holes 4 and 5, the axes whereof are secant with the deflector 6. The axis of the hole 4 is positioned in the longitudinal direction of the body 1 and the liquids that leave the holes 4 and 5 mix before they come into contact with the deflector 6, which is located downstream from the holes in the direction of flow.

(3) FIG. 2 describes the nozzle according to the invention in a second preferred embodiment wherein the body of the nozzle 1 comprises two chambers 2 and 3, the through-holes 4 and 5 whereof are positioned concentrically in relation to one another. The deflector 6 is in the form of a cone of revolution, the apex whereof is oriented toward the through-holes 4 and 5 and the axis whereof is combined with the axis of said holes, such that the first and second liquids mix at the latest when they come into contact with the deflector.

(4) The invention also relates to a method for spraying a mixture comprising at least a first liquid in the form of a liquid preparation of water-soluble or water-swellable polymers wherein the content by weight of polymer is preferably between 0.01% and 75% and at least a second liquid implementing the nozzle previously described. More preferably, the content by weight of polymer for the first liquid is between 5 and 60% and still more preferably between 10 and 50%.

(5) By definition, a water-soluble polymer is a polymer that gives an aqueous solution without insoluble particles when it is dissolved with stirring at 25° C. and with a concentration of 50 g.Math.L.sup.−1 in water.

(6) A water-swellable polymer is a polymer that swells and thickens the aqueous solution when it is placed in water at 25° C.

(7) For the method according to the invention, the second liquid is aqueous or organic or a mixture of the two.

(8) Still more preferably, the second liquid assumes the form of a water-in-oil emulsion or the form of an aqueous dispersion of particles.

(9) According to one preferred embodiment, for the spraying method of the invention the second liquid contains at least one substance of agronomic interest or at least one substance making it possible to improve the development or growth of plant material, preferably a substance chosen from fertilizers, hormones, microorganisms, mycorrhizae, growth stimulators, growth regulators, phytosanitary products, for example fungicides, insecticides, plant protectors.

(10) According to another preferred embodiment, for the spraying method according to the invention, at least a second liquid contains at least one cross-linking agent.

(11) Still more preferably, the cross-linking agent is chosen from the group comprising alkali or alkaline earth metal hypochlorites or hypobromites, dialdehydes of formula O═CH—(R).sub.n—CH═O for which R is a saturated alkylene chain with 1 to 8 carbons and n=0 or 1.

(12) Preferably, for the spraying method of the invention, the first liquid containing a water-soluble or water-swelling polymer, assumes the form of a homogeneous aqueous solution or a water-in-oil emulsion or a dispersion of polymer particles in aqueous phase.

(13) For the water-in-oil emulsion, the water-soluble or water-swellable polymer is in droplets of water in suspension in the mobile phase that is the oil.

(14) The dispersion of polymer particles in aqueous solution contains particles of at least one water-swellable or water-soluble polymer in suspension in an aqueous solution containing at least one compound chosen from a mineral salt, an organic salt, a dispersant organic polymer and mixtures thereof.

(15) Preferably, for the spraying method of the invention at least one water-soluble or water-swellable polymer contained within at least a first liquid to be sprayed according to the method of the invention, is an acrylamide copolymer.

(16) Advantageously, the comonomers of the acrylamide are non-ionic and/or anionic monomers.

(17) The nonionic monomer or monomers can be chosen, in particular, from the group comprising water-soluble vinyl monomers. Preferred monomers belonging to this class are, for example methacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide and N-methylolacrylamide. It is also possible to use N-vinylformamide, N-vinyl acetamide, N-vinylpyridine and N-vinylpyrrolidone, acryloyl morpholine (ACMO) and diacetone acrylamide.

(18) The anionic monomer or monomers can be chosen from acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS), vinylsulfonic acid, vinylphosphonic acid, said anionic monomer being non-salified, partially salified or totally salified.

(19) The last aspect of the invention relates to the use of the nozzle of the invention to spray at least one preparation of water-soluble or water-swellable polymers in the fields of agriculture, more particularly in order to limit soil erosion, rainwater and wastewater treatment, paper making methods and mining extraction.

(20) In the field of agriculture and more specifically for soil erosion, the water-soluble or water-swellable polymer is advantageously sprayed concomitantly with at least a second liquid containing at least one substance of agronomic interest or at least one substance making it possible to improve the development or growth of a plant material.

(21) The advantages of the nozzle of the invention, the spraying method using this nozzle and the use thereof have been illustrated in light of the following examples, but are not limited thereto.

EXAMPLE 1

Spraying of a Concentrated Mixture of Polyacrylamide with a High Molecular Weight

(22) According to the method of the invention concentrated mixtures of polyacrylamide with a high molecular weight were sprayed using a bi-liquid mirror nozzle equipped with two separate outlet holes.

(23) This nozzle (corresponding to FIG. 1) was modeled in three dimensions then printed using an additive method from PET using an “Ultimaker 2+” printer. The total length of the nozzle is 67 mm, the diameter of the cross-section including the deflector is 12 mm, the diameter of the holes of the chambers is 2 mm and lastly the surface area of the deflector is 112 mm.sup.2.

(24) The nozzle was next equipped with the necessary gaskets before being introduced into a nozzle holder of the “Airjet Bi-Fluid” model of the Teejet brand. This nozzle holder is normally used for spraying with air injection. The use thereof has been adapted in order to allow for the conveyance of two liquids toward the nozzle previously drawn and printed.

(25) Water was circulated in chamber 3 of the nozzle and various concentrated liquid preparations of polyacrylamides in chamber 2.

(26) The polyacrylamides are copolymers of acrylamide and sodium acrylate (70/30, mol %) with a molecular weight of between 10 and 20 million Daltons.

(27) The concentrated liquid preparations (25% by weight) used are described in the following table:

(28) TABLE-US-00001 Preparation Formulation A Aqueous dispersion B Water in oil emulsion

(29) The flow rate of each liquid and the polymer concentrations of the mixtures thus sprayed are indicated in the following table:

(30) TABLE-US-00002 Water Polymer concentration Flow rate Flow rate of the sprayed mixture Trial Preparation (L/min) (L/min). (% by weight) 1 A 0.3 2.2 3 2 B 0.4 2.2 3.85

(31) We obtain spraying in a homogeneous web over a width of more than 40 cm.

(32) According to Kincaid & al (1996) the polymers used cannot be sprayed correctly at a concentration exceeding 900 ppm by weight (0.9% by weight). With the method of the invention, it was possible to spray the same polymers at a concentration more than times higher.

EXAMPLE 2

In Situ Cross-Linking of Polyacrylamide

(33) A method for in situ cross-linking of polyacrylamide was implemented in order to stabilize a soil as described in the document “Crosslinking of acrylamide polymers” U.S. Pat. No. 3,759,857 but implementing the nozzle and the spraying method of the invention.

(34) A liquid preparation of polyacrylamide (molecular weight around 100,000 Da) and a solution of sodium hypochlorite (cross-linking agent) were circulated in each of chambers 2 and 3 of the spray nozzle (identical to that of example 1).

(35) The aim was for the two liquids to mix upon contact with the surface of the deflector (also called mirror) of the nozzle.

(36) The table below summarizes the spraying parameters used:

(37) TABLE-US-00003 Concentration of the active ingredient Chamber of Liquid (% by Flow rate within the sprayed the nozzle weight in water) (mL/min) mixture g/L) 2 Polyacrylamide 11.5% 400 24.9 3 Sodium hypochlorite 1450 0.8 0.1%

(38) Several nozzles were arranged on a spray bar in order to easily apply the mixture of the polymer and the cross-linking agent on the surface of tubs filled with a sandy soil. Once the mixture was applied, the cross-linking induces the formation of a stabilizing layer on the surface of the soil.

(39) It should be noted that the spray nozzles are easily cleaned after spraying. No cross-linking and therefore no clogging occurred inside the spraying equipment.