WO2012045402A1

WO2012045402A1 - Portable sprayer for liquid or semiliquid products.

Info

Publication number: WO2012045402A1
Application number: PCT/EP2011/004796
Authority: WO
Inventors: Giacomo Meo
Original assignee: Di Martino S.P.A.
Priority date: 2010-10-06
Filing date: 2011-09-26
Publication date: 2012-04-12
Also published as: IT1402285B1; ITVI20100270A1; EP2624963A1

Abstract

A portable sprayer for liquid or semiliquid products, including at least one Container (2) for a product to be dispensed which is associated with a pump assembly (100) which is actuated by an actuation means and is connected to a dispensing device. The pump assembly includes at least one screw piston (110), which interacts with the actuation means and is guided with a reciprocating combined rotary and translational motion in a hollow body (130) which is integral with the Container (2) and is provided with at least one intake port (137) and at least one delivery port (138).

Description

PORTABLE SPRAYER FOR LIQUID OR SEMILIQUID PRODUCTS

The present invention relates to a portable sprayer for liquid or semiliquid products.

Various types of manually-actuated portable sprayers are known which can be used to spray and disinfest crops and ornamental plants and to distribute liquid-based products while enjoying hobby or during a production work.

Conventional sprayers are essentially constituted by a container having a positive-displacement pump, connected to a dispensing nozzle.

The pump can be usually actuated by means of a lever which, by means of a rod- and-crank mechanism or a cam system, converts the angular motion imparted by an operator respectively into the reciprocating rectilinear motion of a piston or into the oscillation of a membrane inserted in the pump.

Generally, the pump interacts with a compression chamber which allows to dampen the pressure pulses caused by the deliveries of the pump and to allow the operator a few dispensing seconds without continuously actuating the lever.

The compression chamber may be incorporated in the structure of the piston and may move with the same reciprocating motion, or may be constituted by a separate tank that remains fixed with respect to the container.

Despite being advantageous in many respects and substantially meeting the need, conventional portable sprayers have various drawbacks.

A first drawback consists in that much of the energy expended by the operator is dissipated in friction among moving parts that are not directly involved in the generation of the pressure.

It is sufficient to consider, in this regard, the dissipative forces that occur at the lever and at the traction elements that constitute the rod-and-crank mechanism or at the compression chamber incorporated in the piston.

It should also be considered that the transmission of the reciprocating motion to the piston by means of a mechanical lever system has functional limitations, such as the ratio between the dimensions of the lever arms, the extent of the stroke and the length of the lever. Accordingly, when the pressure in the tank exceeds 3÷4 bar, the effort required to actuate the lever increases exponentially until it becomes very difficult for the user.

Also, the forces generated by this system tend to compromise the life and reliability of the structure, causing for example the failure of the elements that compose the rod-and-crank mechanism.

Also, from a manufacturing point of view, the assembly of a pump with a lever system tends to be onerous both in terms of increased time and in terms of higher costs.

The aim of the invention is therefore to solve the problems described above by providing a portable sprayer for liquid or semiliquid products, in which it is possible to transmit the reciprocating motion to the piston, with less effort with respect to a conventional sprayer having the same dispensing pressure.

Within the scope of this aim, a particular object of the invention is to provide a portable sprayer that can impart the reciprocating motion to the piston directly by means of the actuation lever and therefore without using rod-and-crank mechanisms.

Another object of the invention is to provide a portable sprayer in which the reduced effort of the pumping maneuver allows to reduce operator fatigue and to increase the dispensing pressure in order to optimize the atomization of the product.

Another object of the invention is to provide a portable sprayer that can be used both with liquid-based products and with fluids that have a more viscous consistency.

Another object of the invention is to provide a portable sprayer that has a higher reliability and a longer life.

Another object of the invention is to provide a portable sprayer that can be assembled easily, can be disassembled completely and is also advantageous from a purely economic standpoint.

This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a portable sprayer, particularly for liquid or semiliquid products, comprising at least one container for a product to be dispensed; said container is associated with a pump assembly which is actuated by an actuation means and is connected to a dispensing device; said portable sprayer is characterized in that said pump assembly comprises at least one screw piston which interacts with said actuation means; said screw piston is guided with a reciprocating combined rotary and translational motion in a substantially complementarily shaped hollow body which is provided with at least one intake port and at least one delivery port; said hollow body is associated with said container.

Further characteristics and advantages will become better apparent from the description of preferred but not exclusive embodiments of a portable sprayer according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a front view of a portable sprayer according to the invention;

Figure 2 is a bottom view of the portable sprayer according to the invention;

Figure 3 is another bottom view of the portable sprayer according to the invention;

Figure 4 is a partially sectional front view of the portable sprayer according to the invention;

Figure 5 is a perspective view of a component of the portable sprayer according to the invention;

Figure 6 is an exploded perspective view of the component of the preceding figure;

Figure 7 is a front view of a further embodiment of the portable sprayer according to the invention;

Figure 8 is a perspective view of a component of the portable sprayer of Figure 7; Figure 9 is an exploded perspective view of the component of the preceding figure.

With reference to the cited Figures 1 to 6, a portable sprayer, particularly for liquid or semiliquid products, generally designated by the reference numeral 1 , includes a container 2 for the product to be dispensed and a pump assembly 100 associated with the container.

According to a preferred embodiment, the container 2 is made of corrosion- resistant polymeric material; however, the container 2 may be also made of materials such as copper and stainless steel that are equally resistant to chemical and atmospheric agents.

A base 5 is joined to the container 2 for facilitating the resting of the portable sprayer 1 on the ground and also for creating a technical compartment adapted to accommodate part of the other components.

Conveniently, the container 2 is equipped with a pair of adjustable straps 6a and

6b, having ends fastened respectively to eyelets 7a and 7b and to hooks 8a and 8b.

While the eyelets 7a and 7b are formed in the upper part of the container 2, the hooks 8a and 8b are provided in the central portion of the base 5.

An inlet 3, arranged above the container 2, is closed by a removable plug 4, optionally provided with a screen, not shown in the accompanying figures.

The pump assembly 100 is arranged in the lower part of the container 2, inside the technical compartment formed by the base 5. The pump assembly 100 is connected to an accumulation tank 160, which is connected to a dispensing device.

The dispensing device may be of a per se known type and therefore is not shown in the figures. The dispensing device is essentially constituted by a flexible hose which ends with an adjustable spray nozzle.

It should be noted, in any case, that by virtue of its particular structural characteristics the pump assembly 100 may be arranged outside the container 2 as well as outside the technical compartment formed by the base 5.

According to the invention, the pump assembly 100 includes a screw piston 110, which can be actuated by virtue of an actuation means 10 and is guided with a reciprocating combined rotary and translational motion in a hollow body 130. The hollow body 130 is shaped substantially complementarily to the screw piston 110 and is fastened to the container 2 or to the base 5.

In a preferred embodiment, the screw piston 110 and the hollow body 130 are made of self-lubricating synthetic material; however, the choice might also fall onto other substantially equivalent materials known to the person skilled in the art.

The screw piston 110 is constituted by a head portion 111 connected to a tail portion 112; both are substantially cylindrical, but according to a preferred embodiment the diameter of the head portion 111 is smaller than the diameter of the tail portion 112. The head portion 111 is slidingly accommodated in a corresponding cylinder 131 , which is provided in the hollow body 130 and has an intake port 137 and a delivery port 138.

Preferably, the head portion 111 is provided with one or more sealing rings, which, in the illustrated example, are designated by the reference numerals 113 and 114. Sealing rings 113 and 114 are inserted respectively in circumferential seats 115 and 116, formed on the side wall of the head portion 111 , substantially at the free end of the head portion.

The tail portion 112 is arranged in a substantially complementarily shaped receptacle 132, provided in the hollow body 130 and blended with the cylinder 131.

A pair of helical recesses 117 and 118, arranged on the lateral surface of the tail portion 112, create a helical coupling with a pair of corresponding helical protrusions 133 and 134, formed on the side wall of the receptacle 132.

In practice, the helical recesses 117 and 118 and the helical protrusions 133 and 134 constitute a thread which converts the rotations of the tail portion 112 into forward and backward movements of the head portion 111 in the cylinder 131. The pitch of the thread is preset during construction and is chosen so as to optimize the ratio between rotation and advancement.

As has been pointed out, it has been found that it is particularly advantageous to provide for the presence of two helical recesses and two corresponding protrusions; however, nothing forbids changing their number during production.

The bottom of the hollow body 130, i.e., the end of the receptacle 132 that is not blended with the cylinder 131 , is closed by a removable cover 135, which can be conveniently removed, if it is necessary to remove the screw piston 110 from the hollow body 130.

A one-way intake valve 140 and a one-way discharge valve 150 are arranged on the opposite end of the hollow body 130, i.e., on the part that corresponds to the end of the cylinder 131 that is not blended with the receptacle 132. The one-way intake valve 140 and the one-way discharge valve 150 are respectively associated with the intake port 137 and with the delivery port 138. The two one-way valves allow alternately the inflow of the product to be dispensed into the cylinder 131 , drawing it from the container 2, and the introduction from there into the accumulation tank 160 which is interposed between the pumping assembly 100 and the dispensing device.

The accumulation tank 160 performs the function of containing the pressure variations caused by the reciprocating motion of the screw piston 110, smoothing the distribution of the product to be dispensed.

With particular reference to the embodiment shown in the figures, the accumulation tank 160 is located inside the container 2, to which it is fixed, and is equipped with an overpressure valve 161 , which however is not indispensable to ensure the correct operation of the entire device.

However, it should be noted that the accumulation tank 160 may also be arranged outside the container 2.

In any case, regardless of the position of the accumulation tank 160, it is important to consider that, by keeping the tank fixed with respect to the container 2, many of the problems related to friction and losses disappear, considerably increasing the performance of the portable sprayer 1.

As mentioned above, the motion of the screw piston 110 is induced by an actuation means 10, which is constituted essentially by an actuation lever 11 which is fastened transversely to a shank 119 that protrudes from the base of the tail portion 112.

The shank 119 protrudes from a hole 136 which is provided centrally with respect to the removable cover 135 and is joined to the actuation lever 11 by means of a fork member 12, in which it is inserted and locked with adjustable positioning.

The free end of the fork member 12 is in fact provided with a diametrical through hole 13, inside which there is a screw 14, which is inserted in corresponding pairs of diametrical holes 120 or 121 arranged in different directions and is coupled to a nut 15.

In any case, the possibility to modify the position of the actuation lever 11 with respect to the shank 119 is not decisive for the good operation of the device.

Conveniently, the actuation lever 11 , and accordingly also the pump assembly 100, may be modified during production to be positioned on the right side or on the left side of the container 2 according to the requirements.

According to a further embodiment of the invention, illustrated in Figures 7 to 9, the portable sprayer, generally designated by the reference numeral 1001 , comprises actuation means 1010.

The actuation lever 1011 is fastened, with an adjustable position, to a shank

1119 that ends with an oval head 1120 that protrudes from a corresponding hole 1136 provided in the cover 1135.

The oval head 1120 is interlocked in a complementarily shaped oval pocket

1012, which is formed on the internal surface of the actuation lever 1011 , and is locked by a knob 1013, which engages a threaded through hole 1121 provided centrally with respect to the oval head 1120.

In the portable sprayer 1001 , according to this embodiment, also the system for anchoring the adjustable straps 6a and 6b is modified with respect to the one of the previously described embodiment.

In particular, the adjustable straps 6a and 6b are anchored, in the upper region, by means of eyelets 1007a and 1007b that protrude from a collar 1009 detachably joined to the inlet 3.

The collar 1009 is provided with a thread, formed on its internal surface, which allows to screw it onto the inlet 3 without hindering the correct positioning of the removable plug 4.

Hooks 1008a and 1008b, provided laterally with respect to the base 5, are used for fastening the straps in the lower region.

In the embodiment illustrated in Figures 7 to 9, the elements that correspond to the elements already described with reference to the embodiment shown in Figures 1 to 6 have been designated by the same reference numerals.

The operation of the portable sprayer according to the invention is evident from what has been described above.

In particular, it is evident that the angular motion imparted by the arm of the operator to the actuation lever 11 is converted into the reciprocating combined rotary and translational motion of the screw piston 110, which is moved from the bottom dead center to the top dead center and vice versa.

The movement of the screw piston 1 10, and in particular of the head portion 1 1 1 , initially draws the product to be dispensed into the cylinder 131 and then pumps it into the accumulation tank 160 so that it can supply the dispensing means.

In practice it has been found that the portable sprayer for liquid or semiliquid products, according to the invention, fully achieves the intended aim, since for an equal delivery pressure the effort of the operator on the lever is reduced considerably with respect to the effort required to actuate any other existing pump.

The transmission of the reciprocating motion to the piston, obtained by means of the described system, is in fact less tiring and therefore requires less expenditure for an equal pressure.

Also, the portable sprayer according to the invention, which does not use rod- and-crank mechanisms, reduces the effort required for the pumping maneuver and allows to increase the delivery pressure, optimizing the atomization of the product.

The portable sprayer according to the invention is easy to assemble and allows complete disassembly, is particularly reliable and durable, ensuring an operation of at least 500,000 cycles without maintenance.

This application claims the priority of Italian Patent Application No. VI2010A000270, filed on October 6, 2010, the subject matter of which is incorporated herein by reference.

Claims

1. A portable sprayer, particularly for liquid or semiliquid products, comprising at least one container for a product to be dispensed; said container is associated with a pump assembly which is actuated by an actuation means and is connected to a dispensing device; said portable sprayer is characterized in that said pump assembly comprises at least one screw piston which interacts with said actuation means; said screw piston is guided with a reciprocating combined rotary and translational motion in a substantially complementarily shaped hollow body which is provided with at least one intake port and at least one delivery port; said hollow body is associated with said container.

2. The portable sprayer according to claim 1 , characterized in that said screw piston comprises a substantially cylindrical head portion, which is slidingly accommodated in a cylinder provided in said hollow body; said cylinder is shaped substantially complementarily to said head portion and comprises said intake port and said delivery port.

3. The portable sprayer according to one or more of the preceding claims, characterized in that said screw piston comprises at least one sealing ring, which is inserted in a circumferential seat formed on the side wall of said head portion.

4. The portable sprayer according to one or more of the preceding claims, characterized in that said screw piston comprises a substantially cylindrical tail portion, which is inserted with a helical coupling in a receptacle provided in said hollow body; said receptacle is shaped substantially complementarily to said tail portion and is blended with said cylinder; said tail portion is connected to said head portion and interacts with said actuation means.

5. The portable sprayer according to one or more of the preceding claims, characterized in that said screw piston comprises at least one helical recess provided on the lateral surface of said tail portion; said helical recess is coupled to at least one corresponding helical protrusion defined on the side wall of said receptacle.

6. The portable sprayer according to one or more of the preceding claims, characterized in that said hollow body comprises a removable cover which is associated with the end of said receptacle that is not blended with said cylinder.

7. The portable sprayer according to one or more of the preceding claims, characterized in that said pump assembly comprises at least one one-way intake valve, which is associated with said intake port, and at least one one-way discharge valve, which is associated with said delivery port; said one-way valves allow alternately the inflow into the cylinder of said product to be dispensed and the outflow from the cylinder of said product to be dispensed.

8. The portable sprayer according to one or more of the preceding claims, characterized in that it comprises at least one accumulation tank, which is fed with said product to be dispensed by means of said one-way discharge valve and is connected to said dispensing device; said accumulation tank is coupled to said container.

9. The portable sprayer according to one or more of the preceding claims, characterized in that said accumulation tank comprises at least one overpressure valve.

10. The portable sprayer according to one or more of the preceding claims, characterized in that said actuation means comprises an actuation lever which is fixed with adjustable positioning to a shank which is joined to said tail portion; said shank protrudes through an opening provided centrally with respect to said cover.

11. The portable sprayer according to one or more of the preceding claims, characterized in that it comprises at least one collar which is detachably joined to the inlet of said container; said collar is provided with at least one eyelet adapted to receive straps.