FR2560695A1 - PRESSURE REGULATOR, IN PARTICULAR FOR A SPRAYING PLANT OF A TREATMENT LIQUID - Google Patents

Abstract

THE INVENTION RELATES TO A PRESSURE REGULATOR. THIS REGULATOR INCLUDES A CHAMBER 8, CROSSED BY THE LIQUID TO BE REGULATED UNDER PRESSURE P; THE OUTLET TUBING 10 IS EQUIPPED WITH A VALVE 11A-11B, OF WHICH THE BODY 11B IS CARRIED BY A PISTON 12, INTERPOSED TIGHTLY (MEMBRANES 15 AND 18) BETWEEN CHAMBER 8 AND AN ACCUMULATOR 14, FILLED WITH AIR UNDER A PRESSURE P; THE ASSEMBLY IS DIMENSIONED SO THAT P IS WIDELY INDEPENDENT OF VARIATIONS IN P. THE INVENTION IS APPLICABLE IN PARTICULAR TO THE REGULATION OF THE SUPPLY PRESSURE OF DEVICES FOR SPRAYING A PLANT OR SOIL TREATMENT LIQUID.

Description

The present invention relates to a pressure regulator, in particular

  for a spray plant of a plant treatment liquid or

of the ground.

  The spraying installations of a treatment liquid, which are used in agriculture, arboriculture, etc., generally each comprise a liquid pump which supplies in parallel different spray devices, for example several spray bars, whose feeds in liquid can be opened or closed independently of each other, for example depending on the number of ramps to be used for a particular operation

  spray. The feed pressure of the different

  sprayers, and, consequently,

  their flow, depends on the number of spray ramps

  are in use, so that the flow rate of each ramp in use depends on the number of ramps that are not. On the other hand, these spray systems are generally equipped with simple and robust pumps, but have the disadvantage to discharge the treatment liquid in a pulsating manner, which again causes periodic variations in the supply pressure of the various ramps:

and hence their flow.

  The pressure regulator according to the present

  invention is of the type indicated initially, and

  When incorporated in a process for pulverization of a treatment liquid, it makes it possible to overcome the drawbacks just mentioned. It is known from pressure regulators each having a chamber with an inlet pipe for the liquid. under variable pressure, and a seat for

  an outlet valve body, integral with a piston.

  Some of these pressure regulators have already been used in spraying installations of a treatment liquid, as described for example in French Patent No. 77.28.895 that the applicant filed on September 26, 1977; in the installation described in this patent, the piston of the regulator is interposed with sealing between the mentioned chamber and an auxiliary circuit of liquid, for example oil, independent of the circuit of the treatment liquid, and installed in an oscillating arm provided with a wheel intended to be driven at a speed proportional to the forward speed, so as to ensure the spreading of a constant volume of treatment liquid per unit area

  despite the change in the speed of the vehicle

  who carries or pulls the spray system.

  The pressure regulator described in this prior patent is therefore designed to solve another problem, and it is inseparable from a relatively complex device, adapted to subject the two faces of the piston of the regulator to the pressures of two separate liquid circuits. Also known are pressure regulators of the type previously indicated, in which a spring, or a similar elastic member, applies to the piston a force, generally adjustable, tending to push the body of the outlet valve towards its seat. These spring-loaded regulators have the following disadvantage: when the regulation pressure has to be high, the spring must for example be strongly compressed, so that its still available compression stroke is much lower than when the spring is only weakly compressed, for a fairly low regulation pressure; as a result, the relative variations of the pressure to be regulated that such a regulator can compensate effectively are much more

  weak at high pressures than at low pressures.

  Pressure regulator according to this

  invention also comprises a chamber with a tubular

  inlet lure for the variable pressure fluid and a seat for an outlet valve body integral with a piston; However, it differs from the regulators that have been mentioned above, in that its piston is interposed with sealing between the chamber and an accumulator filled with a compressible fluid, said piston has a cross section greater than that of the

  valve seat, and that the chamber, piston and accumulator

  emulator are sized so that the pressure of the fluid in the accumulator is substantially inde-

  the pressure and the flow of the incoming liquid.

  If, for example, the spraying plant

  In which the pressure regulator according to the present invention is incorporated, it operates with all its ramps in operation, and if, for example, the feeds of several of the ramps in service are interrupted simultaneously, this results in a significant increase in pressure. liquid entering the hardener chamber, and consequently a significant increase in the distance between the valve body and its seat, therefore an increase in the flow rate through said valve, and a reduction in the pressure of the incoming liquid; as the valve body is integral with the piston, the latter penetrates further into

  the accumulator, but because of the appropriate sizing

  required of the chamber, the piston and the accumulator, this displacement of the piston has an amplitude sufficiently

  low to result in a practical increase

  negligible amount of pressure in the accumulator; it is understood that the strong increase, mentioned, of the pressure of the incoming liquid results in an almost negligible increase in the pressure of the liquid which

  out of the regulator to feed the spray ramps.

  In this case, the flow of the latter is practically unaffected by the shutdown of the power supplies of the decommissioned ramps. Similarly, the periodic pressure variations due to the pulsating discharge of the pump of the installation are largely compensated by the pressure regulator according to the present invention, and are therefore not reflected in the liquid that leaves the regulator to supply the ramps

spray.

  Moreover, as the compressibility of

  fluid filling the accumulator is almost inde-

  Because of the pressure of this fluid, which must be adapted to the pressure of the liquid entering the regulator according to the invention, the latter can compensate with the same efficiency the relative variations in the pressure of the incoming liquid, that it is low. or strong,

  contrary to what happens in the case of

  pressure transmitters with springs, depending on the

been stated previously.

  By way of example, the following has been described and schematically illustrated in the accompanying drawing, a form

embodiment of the invention.

  Figure 1 is a diagram of a spraying plant of a treatment liquid, in which is incorporated a pressure regulator according to the present invention. Figures 2 and 3 are views, in section through an axial plane, of two pressure regulators according to the present invention, which can be used in

the installation of Figure 1.

  In FIG. 1, I designates a reservoir for processing liquid, 2 a pump adapted to draw the liquid into the reservoir 1 and to pulsate it in a general pipe 5, which feeds in parallel, for example, three spray bars 4a. 4c, that control devices, 5a to 5c, for example maneuverable manually, can turn on and off. A pressure regulator according to the present invention, R, can be inserted in a return line 6, which connects the main pipe 3 to the

  liquid treatment tank 1.

  The embodiment of the regulator R, which is shown in axial section in FIG. 2, comprises a casing 7, for example symmetrical of revolution around

  of the A-axis and made of a suitable molded material.

  The casing 7, whose upper face is open, delimits a chamber 8 into which an inlet side pipe 9 opens, which, in the installation illustrated in FIG. 1, is connected to the general pipe 3. The lower wall the casing 7 is traversed by an outlet pipe 10, which extends downwards in the direction of the axis A. At the outlet of the pipe 10 in the chamber 8 is disposed a valve seat 11a, made of a resistant material suitable, with which can cooperate a valve body 11b, also made of a suitable resistant material; the seat 11la and the body 11b can cooperate by ground surfaces,

  for example frustoconical ax A. A piston 12 is inter-

  posed, according to the present invention, between the chamber 89

  delimited by the casing 7, on the one hand, and the underside

  an open, bell-shaped, bell-shaped part 13, whose open bottom face is provided with a lateral flange 1.3a, pointing to its sealed connection - by known means, not shown at the upper edge of the casing 7, so that said piece 13 delimits, beyond the piston 12, a chamber 14 of large volute constituting, as will be explained later in more detail, an air accumulator. The tightness at the piston 12 is ensured, the e8té of the air accumulator 149 by an upper flexible membrane 15, whose outer edge, has, is embedded between a lower flange, 13b, the piece-shaped bell 13, on the one hand, and an outer radial flange, 16a, of a ferrule 16, coaxial with AqdmitrePrte while its inner edge, 15b is embedded between the upper face of the piston 12 and an annular piece 17, which is subject to its upper surface, by appropriate means, not repreented. Similarly, the anchorance of the piston 12 of the side of the chamber 8 is ensured by a second, lower, flexible membrane 18 whose outer edge 18a is embedded between a countersink 7a, arranged on the inner face of the casing 7. coaxially with the axis A, and an internal radial flange, 16b, of the shell 16, while the inner edge, 18b, of the membrane 18, is embedded between the lower face of the piston 12 and an annular piece, '19, which is attached to said underside

  of the piston 12 by appropriate means, not shown.

  The arrangement is such that the cross section of the crew formed by the piston 12 and by the membranes and 18 has different values, corresponding in particular, on the side of the air accumulator 14, to a diameter D, which is notably greater than diameter d corresponding to the side of the chamber 8. Furthermore, the lower annular cover piece 19 forms an external radial flange on a cylindrical sleeve 19a, coaxial with A; in this embodiment, the two parts 19 and 19a are integral, for example integrally molded, and the sleeve 19a extends below the annular cover piece 19, so as to support the valve body 11b, this last having for example the form of a cup, whose side wall has been embedded in the molding

  in the lower part of the sleeve 19a.

  In the embodiment of FIG. 2, the upper wall of the bell-shaped part 13, which constitutes the air accumulator, is traversed by a self-closing valve 20, which can be connected, for example by means of an external thread a, at the end of a connecting pipe to a source of pressurized air, such as an air compressor or a compressed air tank, for filling the chamber 14 of the air accumulator. This automatic shut-off valve is of a well-known type, which need not be described in detail, and which also allows its temporary opening by a simple manual action, for the total or partial emptying of the valve. chamber 14 of the accumulator. On the other hand, an air pump, in particular a hand pump, is mounted along the axis A, so as to pass through the upper wall of the bell-shaped part 13; the cylindrical body, 21, of this hand pump, for example comes from molding with the bell-shaped part 13; it extends over appropriate lengths above the piece 13 and, inside thereof, substantially to the level of the upper annular piece 17; in the embodiment considered, the body 21 of the hand pump is extended downwards by a sleeve 21a, which engages with play -à- inside a barrel, 17a, come molding on the upper face of the upper annular piece 17, so as to guide the movements of the crew 12-15-17-18-19-19a-11b in the direction of the axis A. In the body 21 of the pump can slide two pistons, 22a and 22b, provided with seals, 23a and 23b, and joined by a metal rod 24, whose upper end is extended by an operating handle 25. At the lower end of the pump body 21 is arranged a valve

  25 of a known type, which allows the repression

  in the chamber 14 of the air accumulator, atmospheric air which has been compressed in the pump body 21 when the operator has exerted a thrust

down on the handle 25.

  The operation of the powder plant

  1 and 2 and previously described is as follows: The pressure of the air in the chamber 14 of the accumulator will be denoted by γ the pressure, at a given moment, of the treatment liquid in the chamber. intake manifold 9, by S the surface of the movable element 12-15-17, on which is exerted the pressure p, by s the surface of the mobile assembly 12-18-19, which is exposed, in the chamber 8, at the pressure P, and shield the section

  effective valve body 11b; with the indi-

  2, i designating in particular the diameter of the seat 11a of the valve, we have: 1) S = 1rD 2/4, 2) = Td2 / 4

D) = = 2/4.

  When the valve 11a-11b is closed, the pressure P of the incoming liquid, which reigns in the chamber 8, exerts on the piston and membrane unit, 12-15-18, an upward force equal to 4) Fa = P (s -Cy), while the air contained under pressure in the chamber 14 exerts on the same crew the downward force) Fd = pS When the crew 12-15-18 is in equilibrium under the action of these two antagonistic forces, Fa and Fd we have the relation 6) P. (s -) = p .., from where we can deduce that the ratio of the pressure p of the air in the accumulator to the pressure of the incoming liquid, P, has the value: 7) p / P = (s -) / s, which is weak, in the measurement o the difference of the surfaces (s - W) can be dimensioned so as to be much smaller than S; this facilitates the filling of

  the accumulator 14 with the air pump, when P is high.

  The embodiment of the invention which is illustrated in FIG. 2 further comprises the following two improvements: On the one hand, the internal volume of the accumulator 14, therefore also the pressure of the air which fills it when the valve 20 is closed, can be adjusted finely by a plunger 30, a manual control 31 can move, from the outside, into a cylinder 32, opening inside the accumulator 14, and, for example molded with the wall of said accumulator 14. On the other hand, the pressure of the air in the accumulator 14 can be read on a manometer

  33, mounted directly on its wall.

  The present invention is not limited to the previously described embodiment. It encompasses all its variants. As already indicated, the filling of the chamber 14 of the air accumulator, instead of being carried out by means of the hand pump 21 to 26, could be carried out with the help of a compressor or other source of compressed air, connected to the valve 20. The sealing means of the piston 12 are optional materials; the flexible membranes 15 and 18 could be replaced by other sealing members such as annular seals. It is not essential that the piston 12 is arranged as a multiplier of the pressure p in the chamber 14 of the air accumulator. Of course, the pressure regulator according to the present invention is usable in all the hydraulic circuits, and not only in the spraying installations

  or injection of a treatment liquid.

  In the second embodiment of

  the invention, which is illustrated in FIG.

  The filter 14 may be filled with a compressible fluid other than air, in particular a gas or vapor which must not escape into the atmosphere for any reason (harmfulness, high cost, etc.); in this case, the upper part of the accumulator 14 is capped by a sealed reservoir 28, in which the compressible fluid is stored at a pressure preferably substantially less than the lowest value at which its pressure in the accumulator 14 can be adjusted. in this reservoir 28 open the suction 27 of the hand pump 21-26 and ale va.lve 20, which must then be provided with a member 29 through said tank 28 with sealing, and able to control 1 opening of Said valve, from above Except that the tank 28 and / or the pump 21-26 could also be independent of the acctuulmattu? 4 to which they would be connected by

suitable pipes.

Claims (10)

  I. Pressure regulator, in particular for a treatment fluid spraying installation, comprising a chamber (8) with an inlet manifold (9) for the variable pressure liquid, and a seat (11a) for a outlet valve body (11b), integral with a piston (12), characterized in that its piston (12) is interposed with a seal between the chamber (8) and an accumulator (14) filled with a compressible fluid , that said piston (12) has a cross-section greater than that of the seat (11a) of the valve, and that the chamber (8), the piston (12) and the accumulator (14) are dimensioned so that the pressure (p) fluid in the accumulator (14) is substantially independent of the pressure (P) and flow of the incoming liquid.   2. Regulator according to claim 1, characterized   characterized in that the accumulator (14) is provided with a valve (20), preferably with an automatic closure, serving   filling and / or emptying said accumulator (14).   3. Regulator according to any one of   Claims 1 and 2, characterized in that a pump,   for example a hand pump (21 to 26), is mounted on the accumulator (1314) so as to allow it to be filled   at the desired pressure with compressible fluid.   4. Regulator according to any one of the   1 to 3, characterized in that the accumulator (14) is filled with air taken from the ambient atmosphere, o open the valve (20) and the pump (21 to 26).   5. Regulator according to claim 3,   characterized in that the valve (20) and the aspirator   (27) of the pump (21 to 26) communicate with a reservoir.   see (28), where the compressible fluid is stored under a pressure significantly lower than its pressure (p) in the accumulator (14), this reservoir (28) being preferably integral with said accumulator (14) and the body (21) of the pump (21 to 26), and that means (29) are provided   to manually control the valve (20).   6. Regulator according to any one of   Claims I to 5, characterized in that it comprises   means for adjusting, from the outside, the internal volume of the accumulator (14), for example in the form of a plunger (30), which can be moved, for example by a manual control (31), in a cylinder (32), opening inside the accumulator (14), and, for example, secured to the wall of said accumulator (14).   7. Regulator according to any one of   Claims I to 6, characterized in that the piston (12)   is a multiplier of the pressure in the emulator (14).   Regulator according to claim 7, characterized   characterized in that the two faces of the piston (12), of   different cross-sections, are connected tightly, for example by flexible membranes (15 and 18),   the largest face, to the side wall (13) of the accumula-   latter (14), and the smaller face, to the side wall (7) of the valve chamber (8).   9. Spray or injection plant   liquid, for example a liquid for the treatment of   plants or soil, equipped with a regulator of   pressure (R) according to any one of claims I to   8, and characterized in that the inlet pipe (9) of   the chamber (8) of the regulator (R) is connected to the re-   of the liquid pump (2), in parallel with the different spraying devices (4a to 4c), and that its outlet valve (11alib-10) is connected to a return line (6), leading to the liquid (1). 10. Sealed receptacle for a fluid under pressure, in particular accumulator for a regulator   pressure device according to any one of claims I   to 8, characterized in that the body (21) of the filling pump of the receptacle is integral with the wall (13) of said receptacle, for example coming from molding with said wall.