FR2778242A1 - Floating gauge especially for measuring the fluid level in a tank especially a phytosanitary tank as used in an agricultural pulveriser or thresher - Google Patents

Abstract

A floating gauge for a tank (21) for an agricultural pulveriser or thresher, where the float (18) changes a liquid display level by means of a flexible connector (26). The tension in the flexible connector can be maintained independently of the liquid level in the tank.

Description

The present invention relates to agricultural sprayers.

  The user of an agricultural sprayer must be able to check at any time, simply and precisely, the level of phytosanitary liquid remaining in

the appliance tank.

  There are mechanical float gauges for this purpose. In these gauges, conventionally, a float ballasted with a counterweight is guided inside the tank of the sprayer by a cylindrical tube comprising a

plurality of orifices.

  This float is connected to a flexible cable which is wound around a drum located outside the tank. This drum in turn activates a slider

  likely to move along a ladder.

  Typically, the diameter of the drum is large (of the order of 50 cm), and the flexible cable does not perform

more than one round.

  Typically also, a helical spring ensures the return of the cursor to the position which corresponds to a

  maximum liquid level in the tank.

  These prior art float gauges

  have several drawbacks.

  First of all, the cursor return means induce a variable tension in the flexible cable which supports the float. It follows that the submerged height of the float varies with the level of liquid in the tank, and therefore that the indication provided by the cursor is likely to be tainted by a certain

error.

  In addition, the large diameter of the drum on which the flexible cable is wound leads to measurements

of mediocre precision.

  Then, the cursor is likely to move when the surface of the liquid is subjected to a chop, which makes the reading of the measurement difficult and

not very precise.

  Added to this is the fact that prior art float gauges are difficult to clean. This is particularly harmful when successively using phytosanitary liquids of different natures: there is a risk of mixing together

  chemically incompatible products.

  The object of the present invention is to provide a float gauge which does not have the above-mentioned drawbacks. This goal, as well as others which will appear on reading what follows, are achieved with a float gauge, in particular for an agricultural sprayer tank intended to contain a phytosanitary liquid, in which said float actuates a display device of the liquid level via a flexible link, remarkable in that it comprises means making it possible to establish in said flexible link a tension independent of the level of said phytosanitary liquid. Other characteristics and advantages of the present invention will appear on reading the

  following description and review of the drawings

  attached given only by way of example, and in which: - Figure 1 is a schematic perspective view of an embodiment of a float gauge according to the invention, - Figure 2 is a sectional view along line II-II of figure 1 of the gauge float, this one

  being shown in the unclipped position.

  As can be seen in FIG. 1, the float gauge according to the invention comprises a device for displaying the level of liquid 1 intended to be placed outside the sprayer tank, in a housing

(not shown).

  This display device includes a pulley

  main 2. This main pulley has a groove

  thread, i.e. a groove that wraps around the surface of the pulley like a screw thread. Alternatively, this main pulley can be smooth and

  include a thread guide (not shown).

  The main pulley 2 is mounted on a first shaft 3 also carrying a tape storage pulley 4. A tape receiving pulley 5 is mounted on a

  second shaft 6 parallel to the first shaft 3.

  A display strip 7, made for example of tear-resistant paper and without elongation, is capable of unwinding from the strip storage pulley 4 to wind around the strip receiving pulley 5

(and vice versa).

  A fixed cursor 8 makes it possible to read values on the

display strip 7.

  The second shaft 6 also carries a spiral spring receiving pulley 9, and a spiral spring storage pulley 10 is mounted on a third shaft 15

parallel to the second tree 6.

  A spiral spring 16 is capable of unwinding from the spiral spring storage pulley 10 to wind around the spring receiving pulley

hairspring 9 (and vice versa).

  In a variant (not shown), the main pulley can be mounted on a first shaft carrying

  also a spiral spring receiving pulley.

  A second shaft parallel to the first shaft carries a spiral spring storage pulley, and a spiral spring is capable of unwinding from the spiral spring storage pulley to wind around the

  spiral spring receiving pulley (and vice versa).

  In this variant, there is therefore no display strip. Measurements can be made, for example, by an electronic position sensor 17

coupled to the first tree.

  Of course, it is also possible to envisage a display device comprising both a strip

  display and an electronic position sensor.

  As can be seen in Figures 1 and 2, the gauge according to the invention also includes a float 18

  having the shape of a flattened crown.

  This float is clipped onto a grapple 19 capable of sliding along at least one vertical rail, and preferably between two vertical rails 20 fixed inside the tank 21 of the sprayer by a flange

  removably mounted on top of this tank.

  The grapple 19 is connected to the main pulley 2 by

  a flexible link such as a metallic cable or the like 26.

  Preferably, as shown in FIG. 2, the end of the flexible link 26 situated on the side of the float 18 supports a counterweight 27, and the flexible link 26 can slide in a channel 28 formed in the grapple 19. The mode of embodiment described above by way of example highlights the advantages of the gauge according to the invention. First of all, the main pulley 2 with thread groove or thread guide allows winding and unwinding of the flexible link 26 without there being any overlapping at its periphery. The flexible link 26 thus applies a force to this pulley at a constant distance relative to its axis. Furthermore, the spiral spring 16 has the particularity of applying a constant torque to the shaft of

the main pulley 2.

  It follows from all of these characteristics that the tension in the flexible link 26 is almost constant, that is to say independent of the level of liquid.

in the spray tank.

  By arranging for this tension to be less than the weight of the float-grapple assembly, a gauge is obtained in which the float 18 floats permanently on the surface of the liquid, and in which the submerged height of this float is constant. As a result, the measurement of the liquid level gains in precision. This precision is further increased by the fact that the flexible link 26 is capable of carrying out several

  turns around the main pulley 2.

  Then, the fact that the flexible link 26 is connected to a counterweight 27 and that it can slide inside the grapple 19 makes it possible to overcome the problems associated with chop and bumps, appearing for example when the sprayer is circulating on rough terrain with the

almost empty tank.

  In fact, when the surface of the phytosanitary liquid rises suddenly, the float 18 also rises abruptly, but the flexible link 26 ballasted with its counterweight 27 remains taut and almost immobile. Thus, the measurement readable on the display device 1 is only slightly affected. In addition, the risks of tangling of the flexible link 26 inside are avoided.

display 1.

  Furthermore, it will be noted that the mounting of the float 18 on rails 20 which pass through it makes it easier to

  cleaning the gauge.

  This arrangement also makes it possible to use a float with a large surface area and a small thickness, which limits errors due to the differences in density of the phytosanitary liquids used.5 Finally, the clipping of the float 18 onto the grapple 19 offers an obvious advantage as to ease of assembly

  gauge in the sprayer tank.

Claims (11)

  1. Float gauge especially for tank (21) of agricultural sprayer intended to contain a phytosanitary liquid, in which said float (18) actuates a device for displaying the level of liquid (1) via a flexible link (26), characterized in that it comprises means making it possible to establish in said flexible link an independent tension   the level of said phytosanitary liquid.   2. float gauge according to claim 1, characterized in that said flexible link (26) is a cable capable of being wound (or unwound) around a main pulley (2) with thread groove or   thread guide mounted on a first axis (3).   3. float gauge according to claim 2, characterized in that said first shaft (3) also carries a tape storage pulley (4), in that a tape receiving pulley (5) is mounted on a second shaft (6) parallel to said first shaft, a display strip (7) being able to unwind from said strip storage pulley to wind around   of said belt receiving pulley (and vice versa).   4. float gauge according to claim 3, characterized in that said second shaft (6) also carries a spiral spring receiving pulley (9), and in that a spiral spring storage pulley (10) is mounted on a third shaft (15) parallel to said second shaft, a spiral spring (16) being capable of unwinding from said spiral spring storage pulley to wind around said pulley   reception of spiral spring (and vice versa).   5. float gauge according to claim 2, characterized in that said first shaft also carries a pulley for receiving spiral spring, and in that a second shaft parallel to said first shaft carries a pulley for storing spiral spring, a spring spiral being capable of unwinding from said spiral spring storage pulley to wind around said spiral spring receiving pulley (and vice versa). 6. Float gauge according to any one of   Claims 2 to 5, characterized in that a sensor   position electronics (17) is coupled to said first tree (3).   7. Float gauge according to any one of   previous claims, characterized in   the end of said flexible link (26) located on the side of said float (18) supports a counterweight (27), and in that said float is slidably mounted relative to said flexible link, so that said flexible link remains taut   and almost immobile even in the presence of choppy water.   8. Float gauge according to any one of   previous claims, characterized in that said float (18) is flat in shape.   9. Float gauge according to any one of   previous claims, characterized in that said   float (18) is a crown capable of sliding on at least one vertical rail (20) fixed inside said tank (21).   10. float gauge according to claim 7, characterized in that said crown is clipped onto a grapple (19) capable of sliding between two vertical rails (20) fixed inside said tank (21),   this grapple being connected to said flexible link (26).   11. Float gauge according to any one of   claims 9 or 10, characterized in that   said rail (s) (20) is (are) integral (s) with a flange (25) mounted removably on top of said tank (21).