FR2842501A1 - Mechanism for pressurizing tank comprises connection to source of fluid under pressure, inlet pipe being closed by piston rod which slides when pressure exceeds threshold value - Google Patents

Abstract

The mechanism for pressurizing the tank (13) of a garden spray comprises a connector (2-4) to a source of fluid under pressure which fills the tank via a non-return valve (7) fitted on a pipe (12). A piston (20) is connected to a piston rod (21) which slides back to seal the pipe when the pressure exceeds a threshold value. An independent claim is included for a spray fitted with the mechanism.

Description

The present invention relates to a device for pressurizing a

  sprayer tank, as well as a sprayer device provided with such a device. This pressurizing device is intended to equip a portable spraying device, of the type comprising a reservoir receiving a spray mixture, generally composed of water and a treatment product, this pressurizing device being able to be actuated to put under pressure the mixture contained

in the tank.

  Spraying devices of this kind are well known, for domestic, agricultural or industrial use, and can have many applications. A common application relates to gardening practiced by amateur or professional gardeners. The invention relates in particular to so-called "pre-pressure" spraying devices in which an overpressure is established in the tank of the spraying device before starting the spraying operation, unlike what is known as "spraying devices" at maintained pressure "which require practically continuous pumping during the actual spraying operation. Overpressure means a pressure higher than the

atmospheric pressure of 1 atm.

  Thus, to carry out a spraying operation using a spraying device of the first type, it is essential to first create an overpressure inside the container to force the mixture therein to be mounted by a dip tube s' extending to the bottom of the tank, run a flexible pipe to reach a liquid spraying device, for example in the form of a gun or a lance. This projection member is also generally equipped

  a projection nozzle and a valve operated by a control member.

  Conventionally, the pressurizing device comprises an air pump which can be actuated manually to discharge air into the tank via a non-return valve which prevents the air from returning back. If the pressure inside the container at the start of the spraying operation is not sufficient to empty all the product contained in the sprayer, a new pumping operation must be carried out. However, these known pressurization devices require significant physical effort from users who can be quickly tired by the efforts associated with pressurizing the liquid before and / or during spraying.

proper.

  To facilitate the pressurization of the tank of the spraying device, devices are known comprising means for connection to a source for distributing a pressurized fluid, in particular to the water distribution network, as well as a non-return valve. mounted passing from the source to the tank. A product to be sprayed is thus introduced into the reservoir which is then closed and connected to the water distribution network. The non-return valve then opens under the pressure of the network water and the tank fills until equilibrium is obtained by compressing the air inside the tank. This pressure equalization will cause the non-return valve to close again under the effect of the action of

its recall spring.

  However, the pressure of the water in the distribution networks varies a lot, usually between 2 and 10 bars, which results in the volume of compressed air in the tank also varying according to this pressure, and consequently the amount of water received in the tank will vary in the same way,

  in accordance with Mariotte's law.

  Even if practically all spraying devices of this kind are provided with a safety valve triggered at a pressure of approximately 3 bars, it remains difficult to regulate the quantity of water admitted into the container below this pressure. To remedy this problem in spraying devices provided with this device for pressurizing by the water distribution network, the Applicant has provided a first solution in its patent application FR 9510309. It is proposed to mount means of automatic closing in the form of a calibrated valve between the non-return valve and the tank, this valve reacting to the pressure in the tank to cut off the water supply to the tank when the pressure reaches a predetermined value. This valve means is associated with a calibration spring which determines the value of the pressure at which this valve means must close the supply. This predetermined value corresponds to a volume of water

predetermined or useful volume.

  Even if this device is generally satisfactory, it can be seen that the automatic closing means are relatively complex and include a large number of parts. These parts also require relatively complicated machining for their manufacture. In addition, the calibration spring makes the closure more or less random because of the manufacturing tolerance which causes a variation in the stiffness from one spring to another. This stiffness is also altered over time. The object of the invention is to propose a pressurizing device which does not have these drawbacks. More specifically, the device according to the invention is extremely simple and comprises a number of parts greatly reduced compared to existing devices. In addition, this new device is easy to manufacture and

implement.

  The object of the invention is a device for pressurizing a tank of a spraying device, this device comprising means for connection to a source for distributing a pressurized fluid for supplying said fluid to said tank. by means of a non-return valve connected to a supply channel capable of opening into said tank, and means for automatically closing said channel under the action of an overpressure acting directly on said means for automatic closing , characterized by the fact that said automatic closing means comprise a control member connected to a rod constituting a closing member capable of projecting into said channel to obstruct the latter when the control member is moved from a position d opening towards

  a closed position under the action of said overpressure.

  According to other characteristics of the invention: said control member is arranged in a cylinder open on one side and closed on the opposite side by a transverse wall provided with a central orifice opening into said channel and closed by said rod, so that a sealed chamber with variable volume as a function of the movement of the control member is defined in the cylinder between said control member and said transverse wall; - Said control member comprises a piston and said rod is a piston rod; the initial pressure inside said chamber when the piston is in said open position is greater than atmospheric pressure and the device comprises at least one stop member for stopping the piston in said open position; - said stop member is provided inside said cylinder; - Said initial pressure is of the order of 1.2 bar; - Said piston rod is guided in a tubular guide member aligned with said central orifice and connected to said transverse wall on the inside of said chamber; - The device comprises an elastic means connected to the piston so as to bias the latter towards said open position; - Said elastic means is a return spring disposed in said chamber and one of whose ends bears against said transverse wall and its opposite end bears against the piston; - Said control member comprises a membrane which in its central part is connected to said rod; - Said source of distribution of a pressurized fluid is a water distribution network;

  - Said connection means are quick connection means.

  Another object of the invention is a spraying apparatus comprising the

  device having the characteristics mentioned above.

  Other characteristics and advantages of the invention will emerge from the

  description which follows of a nonlimiting embodiment of the invention, in

  reference to the appended figures in which: - Figure 1 is a schematic longitudinal section in perspective of a pressurizing device according to the invention; - Figure 2 is a longitudinal section of the device of Figure 1 illustrating the connection of the device on the water distribution network; - Figure 3 is a longitudinal section of the device illustrating the start of pressurization; - Figure 4 is a longitudinal section of the device illustrating the cessation of pressurization; - Figure 5 is a longitudinal section of the device illustrating it at the start of spraying, after disconnection of the water distribution network; - Figure 6 is a longitudinal section of the device illustrating a variant

of it.

  In the figures, identical or equivalent elements will bear the same

reference signs.

  FIG. 1 shows the pressurizing device 1 according to the invention which comprises means of connection 2 to a source of distribution of a pressurized fluid (not shown) which preferably consists of a network of

water distribution.

  These connection means 2 comprise a male tubular member 3 which can be connected to a female tubular member 4 (see FIG. 2) by snap-fastening so as to form a quick connection of the type generally used in gardening. The female member 4 is connected to the water distribution network by a flexible pipe (not shown). The male tubular member 3 has at its end opposite to that of the connection a tapped hole 5, the thread of which cooperates with an external thread on a tubular cylindrical element 6 forming the opening of a non-return valve 7 conventional in itself and which will not be described in detail. This non-return valve 7 comprises a valve body 8 capable of coming to bear against a seat 9 provided on the internal wall of the male tubular member 3 so as to close the passage in the valve. The valve body is

  constantly biased towards its seat by a return spring 10.

  On the opposite side with respect to the valve body 8, the non-return valve has downstream an outlet opening 11 towards a supply channel 12 of the pressurized fluid opening into a sprayer tank 13 which in the figures is schematically indicated by a wall section. The rest of the spraying apparatus will not be described in detail since it is well known to those skilled in the art. The non-return valve 7 is mounted in a tubing 14 of the reservoir which at its free end serves as a bearing surface for a flange 15 on the male connection member 3. The tubing 14 has an internal shoulder 16 against which one of the ends of the male connection member bears when it is screwed onto the

non-return valve 7.

  For fixing the assembly against the wall of the reservoir 13, a flange 17 is provided on the external face of the valve and this flange can thus be tightened against the interior wall of the reservoir when the end of the male connection member comes resting against the shoulder 16 when this member is screwed onto the non-return valve. Conventionally, O-rings 18 are arranged in annular grooves 19 provided on the one hand on the outer face of the male connection member

  3 and on the other hand on the external face of the non-return valve 7.

  The pressurizing device also comprises means for automatically closing the supply channel 12 reacting to an overpressure in the tank.

  13 to close the channel when this overpressure exceeds a predetermined value.

  According to an important characteristic of the invention, these automatic closing means comprise a control member in the form of a piston 20 connected to a piston rod 21 constituting a closing member capable of projecting into the supply channel 12 for obstruct it when the piston 20 is moved from a retracted open position to a closed position under the action of a

overpressure in tank 13.

  The piston 20 is mounted displaceable in a tubular element forming a cylinder 22. This cylinder is open on one side and closed on the opposite side by a transverse wall 23 which constitutes the bottom of the cylinder. This transverse wall is provided with a central orifice 24 opening into the supply channel 12 and which is closed by the piston rod 21. The wall around the central orifice 24 serves as a means of

guide for the piston rod.

  A sealed chamber 25 is thus defined in the cylinder, between the piston 20 and the transverse wall 23. The volume of this sealed chamber can vary as a function of the displacement of the piston 20 under the action of increasing or decreasing pressure in the reservoir 13 thus causing an increase respectively

  a reduction in pressure inside the chamber.

  The initial pressure inside the chamber 25 when the piston 20 is in the open position in which the piston rod 21 is retracted from the channel 12 is higher than atmospheric pressure and is preferably of the order of 1 , 2 bar in order to obtain the closure of the channel 12 by the piston rod 21 when the pressure in the reservoir is of the order of 2.7 bars, which corresponds to a value below the trigger value d '' a safety valve (not shown) which

  generally is calibrated at 3 bars.

  When the tank is empty and the pressure in it therefore corresponds to atmospheric pressure, the higher pressure inside the chamber 25 will urge the piston towards its open position and to stop it in this position and l prevent from leaving the cylinder, the device comprises at least one

  stop member 26, preferably provided inside the cylinder 22.

  The figures show such a stop member 26 disposed inside the cylinder and preferably, a second identical stop member (not shown) is arranged diametrically opposite in the cylinder. The cylinder wall has a groove 27 receiving the stop member for fixing it inside the cylinder at a location which corresponds to an initial pressure in the sealed chamber 25 of the order of 1.2 atm , as already mentioned. For assembly, simply introduce the piston by force into the cylinder and put the stops in place to

prevent him from going back.

  To improve both the guidance of the piston rod 21 in the wall around the central orifice 24 of the transverse wall 23 and the sealing of the sealed chamber 25 while avoiding making this wall relatively thick, a guide member tubular 28 receiving the piston rod 21 is aligned with the orifice

  central and connected to the transverse wall 23 on the inside of the sealed chamber 25.

  Sealing means in the form of O-rings 18 are also arranged in annular grooves 19 provided on the piston rod 21. These O-rings 18 cooperate with the inner wall of the tubular guide member 28 during

  displacement of the piston rod 21.

  Finally, FIG. 6 shows a variant in which an elastic means in the form of a helical return spring 29 has been added in addition to the initial pressure in the sealed chamber 25. This spring serves only to overcome the friction of the O-rings 18 , its stiffness being as low as possible so as not to

  influence the closing accuracy of the device.

  According to a variant not illustrated in the figures, the control member

  comprises a membrane fixed by its periphery inside the tubular element.

  This membrane is in its central part connected to a rod similar to the piston rod 21 and also delimits with the transverse wall 23 a sealed chamber whose volume is variable depending on the pressure exerted against the outer face of the membrane. The chamber also initially has a certain overpressure and the membrane can be moved, in the deformed direction, from this initial position of opening of the supply channel 12 to a closed position.

of it.

  Figures 2 to 5 illustrate the operation of the device according to the invention

  in which the control member comprises a piston 20.

  FIG. 2 shows the device 1 in place in an empty sprayer device reservoir 13, that is to say that the pressure inside the reservoir corresponds to atmospheric pressure. At this instant, the piston 20 is in the open position of the piston rod 20 and the pressure inside the sealed chamber is of the order of 1.2 atm. The male connection member 3 of the device is ready to receive the

  female connection 2 to connect the device to the water distribution network.

  Figure 3 shows the device 1 after connection of the male and female connection members 3, 2 to each other. The pressure of the water in the water distribution network pushes the valve body 8 from the non-return valve 7 so as to let the water pass through the supply channel 12 towards the interior of the reservoir 13. As and when as the water enters the tank, the air is compressed there and the pressure starts to

  increase by acting on the piston 20 in the direction indicated in this figure.

  FIG. 4 shows the device 1 when the pressure inside the reservoir has increased enough to push the piston towards the closed position of the supply channel 12 by the piston rod 21. This means that in the example given , the optimum pressure of 2.7 atm inside the tank is reached and the pressure inside the sealed chamber is also 2.7 atm following the

  air compression in this room.

  The non-return valve closes only after the supply channel 12 is closed by the piston rod 21, and this under the action of its spring.

reminder 10.

  FIG. 5 shows the device 1 at the start of spraying when the pressure inside the tank is optimal, that is to say of the order of 2.7 atm so as not to trigger the safety valve. Then, during spraying, the pressure will decrease and the piston 20 will successively move to its open position shown in Figures 2 and 3 in which the piston rod 21 is fully retracted from the supply channel 12 which upstream will remain closed by

non-return valve 7.

  Normally, the pressure of about 2.7 atm in the tank before spraying begins will be sufficient to completely empty the tank. However, it is of course possible to combine the device according to the invention with a conventional pump which then at the end of spraying would make it possible to complete the pressure if it turns out to be insufficient to completely empty the tank. In this case, a few

  pump strokes would be enough to restore pressure.

  Of course, the invention is not limited to the example illustrated and described, but can be applied to other uses in which the pressurized fluid can

  be other than water obtained from a pressurized supply network.

Claims (13)

  1. Device for pressurizing a tank of a spraying device (13), this device (1) comprising means of connection (2 to 4) to a source for distributing a pressurized fluid for supplying said fluid fluid in said reservoir (13) by means of a non-return valve (7) connected to a supply channel (12) capable of opening into said reservoir (13), and automatic closing means (20 , 21) of said channel under the action of an overpressure acting directly on said automatic closing means, characterized in that said automatic closing means comprise a control member (20) connected to a rod (21) constituting a member closure capable of projecting into said channel (12) to obstruct the latter when said control member (20) is moved from an open position to a closed position under the action of said overpressure. 2. Device according to claim 1, characterized in that said control member (20) is movably mounted in a cylinder (22) open on one side and closed on the opposite side by a transverse wall (23) provided with a central orifice (24) opening into said channel (12) and closed by said rod (21), so that a sealed chamber (25) with variable volume depending on the movement of the control member (20) is defined in the cylinder between said control member and said transverse wall (23).   3. Device according to claim 1 or 2, characterized in that said control member comprises a piston (21) and that said rod is a piston rod (21). 4. Device according to claim 3, characterized in that the initial pressure inside said chamber (25) when the piston (20) is in said open position is higher than atmospheric pressure and that the device ( 1) comprises at least one stop member (26) for stopping the piston (20) in said open position.   5. Device according to claim 4, characterized in that said member   abutment (26) is provided inside said cylinder (22).   he 6. Device according to claim 4 or 5, characterized in that said   initial pressure is around 1.2 bar.   7. Device according to any one of claims 3 to 6, characterized by   the fact that said piston rod (21) is guided in a tubular guide member (28) aligned with said central orifice (24) and connected to said transverse wall (23) on the side interior of said chamber (25).   8. Device according to any one of claims 3 to 7, characterized by   the fact that it comprises an elastic means (29) connected to the piston (20) so as to   urge it towards said open position.   9. Device according to claim 8, characterized in that said elastic means is a return spring (29) disposed in said chamber (25) and one of whose ends bears against said transverse wall (23) and its end   opposite is pressed against the piston (20).   10. Device according to claim 1 or 2, characterized in that said control member comprises a membrane which in its central part is connected to said rod (21).   11. Device according to any one of the preceding claims,   characterized in that said source of distribution of a pressurized fluid is a water distribution network.   12. Device according to any one of the preceding claims,   characterized by the fact that said connection means (2 to 4) are means for quick connection.   13. Spraying apparatus comprising a reservoir (13) intended to contain a liquid to be sprayed, a pressurizing device (1) of said liquid, and a conduit for conveying the pressurized liquid to a projection member, characterized by the fact that said pressurizing device (1) is a device according to one   any of claims 1 to 10.