GB2239317A - Dipstick - Google Patents

Abstract

Liquid storage means comprises a liquid container of high slim mode of construction with an opening (7) arranged in a ceiling region thereof and a liquid level measuring rod (4) of a hard-resilient material introducible into the opening. The cross-sections of the opening (7) and of the rod (4) over the largest part of its length are dimensioned relative to each other for guidance of the rod almost free of play, but so differ from each other in shape that at least one side (42) of the rod, which is provided with a measuring scale, can have no contact with a side of the opening and no contact with any interior wall of the container. Contact is prevented by concave surfaces (42) in a rod (4) whose apexes may define a rectangle, square or triangle. <IMAGE>

Description

LIQUID LEVEL MEASUREMENT IN A LIQUID CONTAINER The present invention relates to liquid storage means and has particular reference to liquid level measurement in a liquid container.

Liquid containers may be equipped with level measuring rods of round or flat rectangular cross-section. Marks for direct reading off of the liquid level in the container are applied to at least one surface of the rod which dips into the liquid. If th measuring rod is wetted up to a particular mark, then a corresponding quantity of liquid is in the container.

In some cases the stored liquid is of such high viscosity that remnants adhere to the container walls above the level of the liquid surface. If the rod is drawn out of the container at an angle such that, after having previously been wiped, an unwetted part of its length touches a wetted part of a wall of the container, liquid adhering to the wall can be transferred to the rod and lead to an error in the reading of the liquid level.

It would thus be desirable to provide liquid storage means in which a previously wiped measuring rod, on renewed extraction from a liquid container, cannot be wetted by liquid adhering to a wall of the container above the liquid level.

According to the present invention there is provided liquid storage means comprising a liquid container of tall and slim mode of construction and provided in a ceiling region thereof with an opening, and a firmly resilient, liquid level measuring rod provided on at least one side thereof with a measuring scale and insertable into the container by way of the opening, the shape of the opening and the cross-section of the rod over the major part of its length so corresponding with each other that the rod: is guided by the rim of the opening to be substantially free of lateral play in the opening but so differing from each other to that said at least one side of the rod is kept free from contact with the rim of the opening and with the interior walls of the container.

Liquid storage means of that kind may ensure that the measuring side of the rod cannot pick up liquid residues even on contact of the rod with an interior wall of the container. Consequently, uncertainty about the actual liquid level may be avoided.

Preferably the measuring rod over the largest part of its length has a cross-section with at least three corners, but at least one side which inwardly of the material differs from a straight line and extends parallelly to one side of the opening cross-section. Thus, the non-parallel sides are directed towards the associated wall of the container and the side extending parallelly to one side of the opening cross-section differs from a straight line in the manner that the surface formed therefrom has a hollow throat shape. Merely its edges situated in the longitudinal direction of the rod can touch the interior wall and be wetted. The surface itself, however, remains dry.

In an advantageous embodiment, the opening has a rectangular cross-section. Several variants of rod cross-section can be used in conjunction with such a shape of the opening. In every case, the rod will be so oriented in the container that no surface provided with the measuring scale can have contact with an interior wall of the container.

In another advantageous embodiment of the invention, the crosssection of the rod has four corners, two short straight mutually opposite sides and two long sides curved arcuately inwards. A measuring rod constructed in such a manner can, even in the case of angled introduction into the container, contact an interior wall of the container at only two edges of the rod. A complete enclosure of the entire circumferential surface profile of the rod is possible only within the liquid, so that the liquid level is visible on the rod by the upper limit of the wetted portion. The arcuate or convex construction of the long sides of the rod cross-section has the advantage that the rod can be easily wiped dry.Although other side shapes differing inwardly of the material from a straight line are possible, for example a box-shape, such a rod may be less easy to clean, as liquid residues may be left on the inward edges of the profile.

Embodiments of the present invention will now be more particularly described with reference to the accompanying drawings, in which: Figure 1 is a schematic elevation of a high and slim liquid container with inserted measuring rod; Figure 2 is a plan view of a top opening of the container and a cross-section of the rod in first liquid storage means embodying the invention; Figure 3 is a plan view of a top opening of the container and a cross-section of the rod in second liquid storage means embodying the invention; and Figure 4 is a plan view of a top opening of the container and a cross-section of the rod in third liquid storage means embodying the invent-ion; Referring now to the drawings, there is shown in Figure 1 a liquid container 1 which is of high and slim construction, i.e. its mutually opposite interior walls 2 and 3 are so close to each other that a liquid level measuring rod 4, on angled withdrawal from the container, can easily touch part of container wall above the liquid level. In the case of a liquid 5 of high viscosity, residues 6 may remain on the walls 2 and 3 of the container and in such a large quantity, notwithstanding gradual reduction of the liquid level, that an obliquely withdrawn rod 4 (position illustrated in dashed lines) can pick up such residues.Consequently, the person reading off the level from the rod may be confused to the extent that the container 1 is taken to be sufficiently filled, even if its true liquid content is exhausted.

To overcome this difficulty, in the embodiment shown in Figure 2 the opening 7 in the container 1 is rectangular and the rod crosssection is so shaped that it can be guided in the opening 7 only in the illustrated orientation. This is ensured, in the case of Figure 2, in that the four corners of the cross-section of the rod 4 coincide at least approximately with the associated corners of the opening 7.

The shorter sides 41 of the rod cross-section are straight and parallel to the associated sides of the opening. Thereagainst, the sides 42 of the rod cross-section are curved inwardly in arcuate shape, so that they have no contact with the associated sides of the opening. Thus, the corresponding longitudinal surfaces of the rod 4 cannot, even in the case of an angled setting of the rod, contact the walls 2 and 3 of the container 1. Only the lateral edges 43 of the rod can be wetted by liquid on the walls ? and 3. On the other hand, the area portions of the sides 42, which have picked up liquid from immersion in the body 5 of liquid, are not wiped by the associated sides of the opening 7.

An equally advantageous embodiment is shown in Figure 3, in which the opening 7 is circularly round. The rod 4 can then be of starshaped cross-section with three, four or more spikes, wherein the sides 44 between respectively adjoining corners 45 are inwardly arcuately curved. In this case, the rotary angle position of the cross-section about the axis of the rod 4 is of no consequence.

Another advantageous embodiment of the invention is illustrated in Figure 4. Whereas the opening 7 is of rectangular cross-section as in Figure 2, the rod 4 can be disposed in a defined position within the rectangle of the opening 7 by virtue of its flattened triangular cross-sectional shape. In that case, two corners 46 of the crosssectional triangle of the rod 4 coincide at least approximately with two adjacent corners of the rectangular shape of the opening 7. The triangle side 47 disposed therebetween is curved arcuately inwards as in the case of the other embodiments. It therefore avoids contact with this interior wall 2 or 3 of the container 1 and with the associated side of the opening 7.

The cross-sectional sides, remote from the sides of the opening, of the rod 4 can instead of the illustrated curved shape, be kinked with sharp edges. Thus, for example, one or two kinks are feasible, wherein two kinks may result in a rectangular or trapezium box shape.

A curved shape is preferred, however, because this shape is easier to wipe off without liquid residue remaining on the hollow throat surface.

Apart from the basic shapes of the rod cross-section discussed above, a U-shaped formation of the rod is also possible. In that case it may be necessary to ensure that no confusion can arise, during reading-off of the measured level, when liquid residues adhere to the outward surfaces of the U-shaped box profile. This possibility could be countered by arranging the measuring scale on only an inward surface of the hollow profile.

Claims (9)

1. Liquid storage means comprising a liquid container of tall and slim mode of construction and provided in a ceiling region thereof with an opening, and a firmly resilient, liquid level measuring rod provided on at least one side thereof with a measuring scale and insertable into the container by way of the opening, the shape of the opening and the cross-section of the rod over the major part of its length so corresponding with each other that the rod is guided by the rim of the opening to be substantially free of lateral play in the opening but so differing from each other that said at least one side of the rod is kept free from contact with the rim of the opening and with the interior walls of the container.

2. Liquid storage means as claimed in claim 1, wherein said crosssection of the rod has at least three corners and at least one recessed side which, when the rod is inserted in the container, extends along one side of the rim of the opening.

3. Liquid storage means as claimed in either claim 1 or claim 2, wherein the opening is rectangular.

4. Liquid storage means as claimed in claim 3, wherein said crosssection of the rod has four corners and two pairs of mutually opposite sides, one pair of sides being straight and the other pair of sides being concave and longer than either of the straight lines.

5. Liquid storage means as claimed in claim 3, wherein said crosssection of the rod has three corners and three sides, two of the sides being straight and the remaining side being concave and longer than either of the straight sides.

6. Liquid storage means as claimed in either claim 1 or claim 2, wherein said cross-section of the rod has four corners and four sides, each of the sides being concave.

7. Liquid storage means substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

8. Liquid storage means substantially as hereinbefore described with reference to Figs.1 and 3 of the accompanying drawings.

9. Liquid storage means substantially as hereinbefore described with reference to Figs. 1 and 4 of the accompanying drawings.