Chemical injection pump

Description

[01] The present invention relates to an adjustable-stroke piston pump for installation in portable sprayers, capable of dispensing liquid chemicals in small quantities on the order of milliliters, such as those used in agriculture, residential or industrial sanitation, among others, being driven by the up-and-down movement of the chamber of a portable sprayer itself, without the need for an additional motive power source. The present injection pump is applicable, for example, in a system for injecting the concentrated chemical product into the hydraulic system of the portable sprayer without the need to contaminate the sprayer tank. That is, the spray tank contains only clean water, reducing the user's contact with the concentrated chemical product and, consequently, increasing operator safety. This application example is what is called direct injection. FIELD OF APPLICATION

[02] The subject matter of the present invention falls within the field of application of chemical products, in agricultural environments or urban pest control, as well as in the field of positive displacement pumps. CONTEXT

[03] In spraying with portable sprayers, which include hand-operated lever sprayers, the most traditional practice is to prepare the spray mixture (a mixture of water and concentrated chemical product) to be used in a large reservoir (for example, 200 liters) and, throughout the day, Petition 870250008323, dated 01 / 31 / 2025, p. 10 / 43 2 / 9 Refill the portable sprayer tank as needed from this large reservoir. In other cases, the user prepares the spray mixture directly in the sprayer tank. In both cases, the resulting mixture can easily contain much more chemical than recommended on the label (overdosage), or much less (underdosage), and this occurs due to possible errors during dilution, such as difficulty in separating the correct volume of chemical to be diluted. In general, lack of control over the amount of product diluted in the mixture compromises the effectiveness of the treatment, increasing costs and environmental impact. In addition, direct contact of the mixture with the portable sprayer tank results in contamination, making cleaning difficult and increasing the user's contact with hazardous products.

[04] One alternative is to inject the chemical product at a point in the portable sprayer where very few parts come into contact with the chemical and, most importantly, without any chemical product entering the sprayer tank, which remains filled only with clean water. This alternative, called direct injection, is carried out using the chemical injection pump, the subject of this patent, as described below. PRIOR ART SEARCH

[05] Patent WO 2017123173 A1 describes a piston pump for transferring chemicals from one reservoir to another. This system uses three distinct pistons, operated together, the first two being dedicated to direct contact with the chemicals and the third to clean water. Specifically, the invention finds application in dishwashers and Petition 870250008323, dated 01 / 31 / 2025, page 11 / 43 3 / 9 employs a system that relies on multiple internal chambers for operation, which increases structural complexity and manufacturing costs, especially when compared to agricultural devices that need to be robust as they operate in harsh weather environments. In the agricultural context, fewer moving parts generally mean greater robustness. Furthermore, the system described in patent WO 2017123173 A1 does not use a floating jacket to modify the stroke and, consequently, the dosage. This element is a critical differentiating factor of the present invention, as it simplifies the adjustment of the pumped volume, reduces the number of components, and minimizes mechanical wear.

[06] Patent CN 113842522 A describes a small piston pump for dispensing small volumes. Its flow control mechanism employs a second chamber with an auxiliary piston and spring system, limiting the stroke of the main piston. In addition to belonging to the field of medical applications, the pump's construction demonstrates fragility and is not a suitable mechanism for continuous operation, since the flow control mechanism limits the system to one injection per cycle, making its applicability in direct injection impossible.

[07] US patent 2017211555 A1 describes a piston pump with adjustable stroke, using an inclined disc mechanism to vary the dosage. This is a system of great constructive complexity and which requires an external energy source, such as combustion or electricity, a source that obviously cannot be found in a portable sprayer.

[08] The present invention differs from prior inventions by offering a simplified dosing system, ideal for application in sprayers. Petition 870250008323, dated 01 / 31 / 2025, page 12 / 43 4 / 9 manual backpack sprayers, and because it is powered by the existing pumping system on the portable lever sprayer, without the need for an additional source of motive power. Another relevant point is the use of a floating jacket system on the pump, as will be detailed. DESCRIPTION OF THE INVENTION

[09] The following descriptions and respective figures are presented to illustrate the invention.

[010] Figure 1 schematically illustrates the assembly of the concentrated chemical pumping system in a portable sprayer. The assembly consists of the sprayer tank (101), whose shape is arbitrary in this illustration, and which stores the water used in spraying. The tank lid (102) is also shown in the figure. The chamber (103) is a pressure vessel where the spray mixture has its pressure increased to allow spraying. The drive system, formed by the rod (104) and the lever (105), transmits the movement made by the user to the chamber (103), providing hydraulic energy to the liquid. In turn, the chamber transmits its movement to the piston pump (107) through the transfer system (106), which connects both parts and equalizes both strokes of the pressurization systems. The sprayer base (108) provides structural support to the entire assembly.The chemical product pressurization system consists of the piston pump (107), responsible for injecting concentrated chemical product, and the reservoir or chemical product bottle (109), responsible for storage.

[011] Figure 2 illustrates one possible example, among others, of the hydraulic circuit of the injection mechanism, where the injection pump, the subject of this study, is located. Petition 870250008323, dated 01 / 31 / 2025, page 13 / 43 5 / 9 patent, and how this is coupled to the portable sprayer. For simplification of the design, part of the sprayer has been omitted. The piston pump (107), or injection pump, when moving upwards, promotes a negative pressure that draws the liquid product contained in the bottle (109), passing through the outlet hose (201), through the (one-way) non-return valve of the pumping system inlet (202) and through its inlet hose (203). When moving downwards, the piston pump (107) pumps the concentrated chemical product through the outlet hose of the pumping assembly (204), passing through the (one-way) non-return valve of the outlet (205) and continuing through the injection hose (206) to the cylinder of the portable sprayer chamber (207), entering through the lid of the portable sprayer (102).

[012] Figure 2 further indicates that the pump (107) injects the concentrated chemical into the cylinder of the portable sprayer chamber (207), which is equivalent to saying that the injection occurs in the low-pressure region of the sprayer. This means that in this region the liquid from the spray tank (101) is not yet pressurized. By injecting the chemical in the low-pressure region, the additional effort to move the injection pump (107) coupled to the sprayer chamber (106) is minimized, which is an advantage of the present invention.

[013] Figure 3 represents the assembled piston pump, object of the present invention, while Figure 4 shows an exploded view of the same, detailing all its parts. The dosing adjustment system is composed of the adjustment knob (301), the spindle (302), the stop (401) and the floating sleeve (303). Next, there is the pumping mechanism, consisting of the piston (402), Petition 870250008323, dated 01 / 31 / 2025, page 14 / 43 6 / 9 by the rubber piston (403), by the outer sleeve (304), by the pump base (305), ball joint support (306) and ball joint (307).

[014] Figures 5 to 8 illustrate the operation of the direct injection pump proposed here. Figure 5 shows the initial configuration of the piston pump, i.e., without dosing or pumping.

[015] Figure 6 illustrates how to perform the dosage. Rotating the adjustment knob (301) causes the spindle (302) to rise, thus determining the height of the stop (401) in relation to the recess of the floating sleeve (303). The stop (401), pinned to the spindle (302), can rise within the slots of the floating sleeve (303) and the piston (402). Therefore, the height of the stop (401) in relation to the base of the floating sleeve (303) defines the Spindle Adjustment Stroke.

[016] Figure 7, when pumping begins, shows the elevation of the floating sleeve (303) relative to the piston (402), this elevation, indicated in the figure as “Stroke Subtracted by the Floating Sleeve”, corresponds to the distance of the “Spindle Adjustment Stroke”, thus, the floating sleeve (303) can move freely until it encounters the stop (401).

[017] Figure 8, when the piston pump completes its full stroke, which originates from and is equivalent to the movement of the sprayer chamber (103), shows that the stroke performed by the floating sleeve (303) is subtracted from the total pumping stroke, resulting in the “Effectively Pumped Stroke” promoted by the piston (402). The piston (402) is responsible for the amount of chemical product to be injected into the cylinder of the sprayer chamber (207), i.e., it defines the dose; therefore, it is necessary to adjust its stroke for correct dosage. The Petition 870250008323, dated 01 / 31 / 2025, page 15 / 43 7 / 9 diameter of the rubber piston (403), as well as the Effectively Pumped Stroke indicated in the figure, is responsible for defining the total volume displaced (expelled or sucked) from the pump.

[018] Figures 9 to 12 illustrate the pump in cross-section and its operation at different stages. Figure 9 shows the minimum possible adjustment of the spindle (302), i.e., the situation in which there is no free stroke and all the movement of the chamber (103) will be transmitted to the piston (302). This situation corresponds to the condition in which the lever (105) of the portable sprayer is lowered.

[019] Figure 10 shows the condition in which the direct injection pump, previously adjusted as in Figure 9, has the floating sleeve (303) fully extended due to the sprayer lever (105) being raised. In this condition, the direct injection pump draws the concentrated chemical product from the reservoir (109) so that the largest possible volume of chemical product is injected into the sprayer chamber cylinder (207). That is, the minimum adjustment of the spindle (302) provides the highest dosage or volume of chemical product.

[020] Figure 11 illustrates the condition in which, through the handle (301), the spindle (302) is at its maximum adjustment. This occurs because when rotating the handle (301), the spindle (302) rises together with the stop (301), creating the largest possible free stroke. In this way, the entire free stroke is subtracted from the stroke performed by the piston (402) when receiving the movement transmitted by the chamber (103), resulting in the smallest pumped volume, as illustrated by Figure 12. Therefore, the maximum adjustment of the spindle (302) provides the lowest dosage or volume of chemical product.

[021] Figures 13 to 16 show a possible Petition 870250008323, dated 01 / 31 / 2025, page 16 / 43 8 / 9 assembly of the pump object of the present invention and its interaction with the mechanical system of a portable lever sprayer illustrative. In these figures the hydraulic circuit containing hoses and valves has been omitted for clarity. For all intents and purposes, it is a system like that already described in Figure 2. Figure 13 shows the lowest adjustment configuration (already described in Figure 9), showing the sprayer lever (105) lowered.

[022] Figure 14 shows the situation already described in Figure 10, this time showing the positioning of the sprayer lever (105). The sprayer user raises the lever (105), causing the chamber (103) to rise. Through the motion transfer system, composed of the transfer beam (1301) and the coupling of the floating sleeve (1302), it transmits its motion to the floating sleeve (303), which in turn transmits it to the piston (402) via the stop (401), drawing in the concentrated chemical product. When the user returns the lever (105) to the position shown in Figure 13, the chemical product is expelled from the direct injection pump described herein and, therefore, into the sprayer system. The manner in which the pumped or expelled liquid is carried to the sprayer is not part of the object of this invention.

[023] Similarly, Figure 15 reinforces what was previously described for Figure 11, but this time showing the state of the sprayer lever (105).

[024] Finally, Figure 16 shows the position of the lever (105) of the portable sprayer used in this example application, with the operation being identical to that already described in Figure 12. Petition 870250008323, dated 01 / 31 / 2025, page 17 / 43 9 / 9

[025] Figure 17 shows the motion compensation mechanism, composed of the ball joint coupling (306) and the ball joint (307). Since misalignments and mechanical clearances exist between the sprayer chamber (103) and the pump (107), the ball joint (307) is introduced to compensate for these irregularities, preventing the pumping system from locking up, by allowing the pump to perform small inclinations in two degrees of freedom. For example, also in Figure 17, a “Vertical Axis” is defined as the ideal direction of the pump and chamber (103), in the absence of misalignments. However, due to alignment variations, the actual movement of the piston occurs along an axis inclined relative to the “Vertical Axis”, called the “Compensation Axis”. This tilting capability prevents the pumping system from locking up, ensuring its smooth and efficient operation.

[026] When observing the operation of the chemical injection pump proposed here, it is observed that it is driven directly by the up-and-down movement of the chamber of a portable sprayer through mechanical coupling between said chamber (103) and a floating sleeve (303). The presence of the floating sleeve (303) allows adjusting the relationship between the stroke of the chamber (103) (which results from the movement that the user makes on the lever (105) of the portable sprayer and which is of variable amplitude) and the stroke of the pump piston, so that the stroke determined by the chamber is compensated by the floating sleeve.

Claims

1. CHEMICAL INJECTION PUMP characterized by being driven by the up-and-down movement of the chamber (103) of a portable sprayer, without the need for an additional power source, through mechanical coupling between said chamber and a floating sleeve (303), wherein the adjustment of this floating sleeve allows the stroke of the pump piston to be different from the stroke of the chamber of the backpack sprayer that drives it, thus making it possible to select the volume of chemical product to be pumped.

2. CHEMICAL INJECTION PUMP, according to claim 1, characterized by containing a threaded spindle (302) that interacts with the stop (401) to delimit the stroke of the floating sleeve (303) and, consequently, the stroke of the piston (402), allowing adjustment of the volume of chemical product injected, so that the maximum stroke of the piston corresponds to the stroke of the chamber (103) of the sprayer, this stroke being reduced only by the action of the stop on the floating sleeve.

3. CHEMICAL INJECTION PUMP, according to claims 1 and 2, characterized in that said spindle (302) has its pitch, that is, the distance the piston advances or retracts with each complete revolution of the spindle, determinable, in the pump design phase, based on the desired dosing accuracy, the adjustment accuracy being inversely proportional to the spindle pitch, so that a smaller pitch results in greater accuracy and control in dosing.

4. CHEMICAL INJECTION PUMP, according to claims 1 and 2, characterized in that the minimum pumped volume adjustable by the user and the maximum pumped volume adjustable by the user are defined by the length of the spindle (302) and the diameter of the rubber piston of the pump (403).

5. CHEMICAL INJECTION PUMP, according to claim 1, characterized by having the pumped volume linearly adjusted by means of the screw (302) and floating sleeve (303) which allows variation in chemical injection, so as to have a minimum dose of 0.1% to a maximum dose of 10% concentration in relation to the flow rate of water sprayed by the portable sprayer where the system is installed.

6. CHEMICAL INJECTION PUMP, according to claim 1, characterized by injecting the concentrated chemical product into the low-pressure region of the portable sprayer, corresponding to the chamber cylinder (207), i.e., at a point before the sprayer's pressurization mechanism.

7. CHEMICAL INJECTION PUMP, according to claim 1, characterized by containing a system for absorbing irregularities and misalignments in assembly formed by a ball joint (307) and a base (306) for the same.

8. CHEMICAL INJECTION PUMP, according to claim 1, characterized by being installable and uninstallable, that is, it can be placed on or removed from the portable sprayer as needed, without requiring modification of the sprayer's functional structure.

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