FR2686651A1 - Device for detecting a drop in a liquid level in a distribution tank - Google Patents

Abstract

The present invention relates to a detection and warning device for regulating the level of a liquid of an engine, comprising a tank (1) inside which is located an element (21) mounted so that it floats on the said liquid and provided, at its upper part, with shut-off means. This device is characterised in that the bottom (31) of the tank (1) comprises, under the said float element (21), a first conductive element (35) connected to connection means (40) and a second conductive element isolated from the said first element (35), and connected to connection means (49), the second conductive element (48) being capable of being applied to the first conductive element when the level of liquid in the tank (1) drops below a predetermined threshold value.

Description

 The present invention relates to a device for automatically detecting and signaling a drop in a level of liquid in a distribution tank, of the type used to supply oil to an automobile crankcase.

 Known devices of this type are, most of the time, constituted by a regulating tank fed at its upper part by an orifice connected to a pipe connected to an oil reservoir, inside which is disposed a float, the upper part of which is provided with a needle, which allows it to close said orifice when a given level of liquid is reached in the tank, the latter being on the other hand connected to the tank in which it is desired to maintain a level constant.

 A number of devices of this type have been proposed which provide automatic regulation of the level of liquid leaving the tank, and in particular inside an engine casing.

 Most of the time, devices of this type do not include means making it possible to detect and signal to the user a lack of oil inside the control tank.

 On the other hand, control tanks of the aforementioned type have the disadvantage, when they are mounted on vehicles which are subjected to unevenness, of having their float inclined relative to the vertical, so that the needle loses its effectiveness and the fluid can therefore flow freely.

 The object of the present invention is therefore to propose a detection and signaling device which, when the level of the liquid in the control tank drops below a predetermined level, achieves the closing of an electrical contact, this closing then being able to, by means of any suitable electrical and / or electronic system, be transformed into a signal intended for the user. The present invention also aims to propose means allowing, when they are in particular used on a vehicle, to stop the flow of liquid supplying, when stationary, the regulating tank when the latter is inclined relative to the vertical.

 The present invention thus relates to a detection and signaling device for a regulator of the level of a liquid in an engine, comprising a tank comprising a first orifice, or upper supply orifice, connected to an inlet pipe liquid and a second orifice, or liquid outlet orifice, tank inside which is arranged a member mounted floating on said liquid, so as to move vertically up or down depending on the level of the liquid inside the tank, this element being provided at its upper part with sealing means intended, when the level of the liquid inside the tank reaches a given predetermined level, to close the above-mentioned orifice supply, characterized in that the bottom of the tank comprises, under said float element, a first element conducting the electric current connected to connection means external to said tank, and a dry a conductive element of the electric current, isolated from said first element, and which is connected to connection means external to the tank, the second conductive element of the electric current being capable of being applied to the first conductive element of the electric current by the weight of the float element when the level of the liquid in the tank drops below a predetermined threshold value.

 In one embodiment of the invention, the first conductive element of the electric current is adjustable in height inside the tank, which makes it possible to adjust the detection threshold from which the electrical contact is established, for example depending on the density of the liquid whose level is to be ensured.

 In a variant of the invention, the second conductive element of the electric current consists of a deformable metal strip, which comes to bear on the first conductive element, under the action of the float, when the level of liquid inside the tank drops below a predetermined threshold.

 In a particularly advantageous variant of the invention, security means are arranged upstream of the detection device, these means comprising a body provided, at its upper part, with a liquid inlet orifice connected to an inlet pipe liquid and, at its lower part, a liquid outlet orifice inside which a valve, symmetrical with respect to a vertical plane, is movably mounted.The valve is mounted oscillating around a horizontal axis, and is provided, at its base, with at least two housings arranged symmetrically with respect to said vertical plane of symmetry and forming with it an angle a, within which are movably mounted at least two shutter elements, the weight and the dimensions of each shutter element and of the valve, the positioning of the center of gravity of the latter, being such that, one of the shutter elements is housed in said outlet port when led it body is inclined at an angle at least equal to the angle a relative to the vertical, and that, the shutter element being housed in said outlet orifice, the valve exerts on the shutter element a restoring force such that it is sufficient to extract said shutter element from the outlet orifice when said body returns to a substantially vertical position.

 In another particularly advantageous embodiment of the present variant, the shutter elements consist of balls, preferably steel balls.

 In another embodiment of the present variant, the valve is made of a liquid-resistant plastic material whose flow is to be controlled, and the amount of the valve return torque is adjusted by adjusting the positioning the center of gravity of the latter by means of a metal counterweight, in particular of lead, on which the valve is overmolded, and the weight of which is determined according to the importance of the desired return torque.

 In another embodiment of the invention, the stops intended to angularly limit the amplitude capable of being taken by the valve are provided on either side of the plane of symmetry of said body.

An embodiment of the present invention will be described below, by way of non-limiting example, with reference to the attached drawing in which
Figure 1 is a longitudinal and vertical sectional view of a liquid level control device equipped with the detection and signaling device according to the invention.

 Figure 2 is a partial view, in longitudinal and vertical section, of the device shown in Figure 1, along line II-II thereof.

 Figure 3 is a schematic view of a device for maintaining the oil level of an engine, implementing the device according to the present invention.

 Figures 4 and 5 are partial views, in longitudinal and vertical section, of the device shown in Figures 1 and 2, for two different positions of the float.

 Figure 6 is a vertical sectional view of an alternative embodiment of the invention showing means for controlling the supply of liquid to the control tank, these means being shown in the open position.

 Figure 7 is a partial sectional view of the control means of Figure 6 shown in the closed position.

 Figure 8 is a sectional view of an alternative embodiment of a valve according to the invention.

 In Figures 1 to 5 there is shown an apparatus for ensuring the maintenance, at a given value, of an oil level in an engine crankcase. This device is equipped with a level detection and signaling device according to the invention. The oil level maintenance device essentially consists of a cylindrical tank 1 with a longitudinal and vertical axis yy ', provided, on one of its generators, with a support element 3, intended to ensure its maintenance . The cylindrical tank 1 is closed by a cover 5 which is screwed at its upper part. The cover 5 comprises an upper axial tube 7 on which is forcibly fitted an oil supply pipe 9, and an event tube 10. The tank 1 is provided, substantially at its lower part, with a radial tube 11 onto which a pipe 13 is force fitted, intended to ensure the connection of the tank 1 with a casing 15 of an engine for which the oil level is to be regulated. The tube 7 is hollowed out with two successive concentric bores, namely a first outlet bore 17 and a second inlet bore 19 of larger diameter which opens onto the interior of the tank 1, these two bores being joined by a frustoconical part which forms a valve seat 20. Inside the tank is arranged a float 21 which is provided, at its upper part, with a rod of hexagonal section 23 terminated by a conical needle 25. the cross section of the rod 23 are such that they allow the latter to slide inside the bore 19, so as to provide longitudinal guidance of the float 21.

 In known manner (as shown in Figure 3) the oil from a supply tank 26 arrives through the pipe 9, then through the bore 17 inside the tank 1, flowing between the internal walls of the bore 19 and the hexagonal external surface of the rod 23, to penetrate into the tank 1. As the oil enters the latter, the float 21 rises until the desired level is reached, the needle 25 is applied to the valve seat 20, and closes the oil inlet bore 19.

 The bottom 31 of the tank 1 is pierced with an axial hole which is traversed by an insulating sleeve 33, inside which is inserted a screw 35, made of a material conducting the electric current, the head 37 of which is arranged in part superior. The screw 35 is held in position by a set of nut and lock nut 38,38 'respectively disposed inside and outside of the tank 1. An electrical connection bar 40 is fixed between the insulating sleeve 33 and the outer lock nut 38 ′, and is thus in electrical connection with the head 37 of the screw 35.

 The side wall of the tank 1 is pierced, substantially at its base, with a radial hole crossed by a second insulating sleeve 42, itself traversed by a screw 44, made of a material conducting the electric current, this assembly being held by an external fixing nut 46. Between the internal wall of the tank 1 and the head 45 of the screw 44 is interposed a flexible metal blade 48, which is folded so as to extend above the screw 35. A connection strip electric 49 is applied against the nut 46 for fixing the screw 44 by another nut 47. Thus the flexible metal blade 48 is electrically connected to the electrical connection strip 49.

 Under these conditions, as shown in FIG. 4, when the oil level in the tank 1 is sufficient for the float 21 not to be in contact with the flexible blade 48, the electrical resistance existing between the two connection bars 40 and 49 is important, since depending on the resistivity of the liquid contained in the tank, of the oil in the present case. When the oil level drops in the tank, as shown in FIG. 5, the float 21 descends and comes to bear against the flexible blade 48 which, under the action of the weight of the latter, deforms. the flexible blade 48, as well as its folding angle a with respect to the side wall of the tank 1, are such that the restoring force capable of being produced by the flexible blade 48, during its deformation, is less than the weight of the float 21, so that, if the level of the oil in the tank 1 continues to decrease, the float 21 applies, under the action of its own weight, the flexible metal blade 48 in contact with the head 37 of the screw 35. At the same time (Figures 1 and 2) the electrical resistance existing between the connection bars 40 and 49 becomes almost zero. This significant variation in resistance is then taken advantage of by electrical and / or electronic systems of any known type to transform it into an appropriate alarm signal.

 In order to be able to adjust the triggering threshold of the device according to the invention, that is to say the level of the liquid from which the electrical contact is established between the two connectors 40 and 49, the screw can be adjusted in height 35 by screwing it in or by unscrewing it more or less.

 Of course one could use, as a lower contact element, replacing the screw 35, any other device, possibly adjustable in height, just as the deformable metal blade 44 could be replaced by a rigid conductive element provided with elastic return means. suitable, for example constituted by a torsion spring. One could also improve the longitudinal guidance of the float by providing, inside the tank 1, longitudinal ribs.

 In Figures 6 to 8 there is shown an embodiment of the invention for preventing the flow of liquid controlled by the control tank 1 when the latter undergoes an inclination relative to the vertical.

 The device consists of a body 60, of cylindrical shape, with a diametrical axis uu 'vertical. The body 60 comprises two diametric tubes, namely an upper liquid inlet tube 62 and a lower liquid outlet tube 64, which open into the body 60 respectively through orifices 63 and 65. These tubes are provided with means for fixing which allow the connection of the body 60 in the liquid supply circuit of the control tank 1, that is to say between the liquid inlet pipe 9 and the orifice 19 of the tank 1, and which allow it to control the liquid supply thereof.

 The center O of the tank 60 has a horizontal axis 66 which supports an oscillating valve 68. The latter, in the present embodiment of the invention, is in the form of a sector and ends at its base with a circular bottom parallel to that of the body 60. Its shape and its weight are such that its center of gravity G is low enough to allow it to maintain a vertical position, in the plane of the body 60, whatever the inclination of the latter relative to vertically. The valve 68 is hollowed out, at its base with two housings 70, of substantially semi-spherical shape, the respective centers of which are offset on either side of the axis uu 'of the body 60 by an angle a. Balls, preferably steel balls 72 with a diameter slightly smaller than that of the housings 70 are housed in the latter.

 When, as shown in Figure 7, the inclination of the body 60 relative to the vertical reaches a value equal to 1 angle a, one of the balls 72 is positioned on the liquid outlet orifice 65 and closes the latter, which at the same time prevents the liquid from reaching the tank 1.

 In this position the ball 72 is held with a force depending, in particular, on its own diameter and that of the orifice 65, so that if the inclination of the body 60, relative to the vertical, continues to increase l the closure of said orifice 65 is nevertheless maintained.

 The distance b separating the circular lower part of the valve 68 from the circular bottom of the body 60 is such that it allows the balls 72 to remain trapped in their respective housings 70, even when they are engaged on the orifice 65, while allowing the valve 68 to move almost without friction on the bottom of the body 60.

 When the body 60 returns to its vertical position, the valve 68, under the action of its own weight, exerts on the ball 72 embedded in the outlet orifice 65, a restoring force tending to extract it from the latter. This restoring force will be determined by playing in particular on the weight of the valve 68, the diameters of the balls 72 and the orifice 65.

 As shown in Figure 8 we can easily adjust the weight of the valve 68, and therefore the restoring force exerted by it on the balls 72, by making it from a plastic material which is molded around a counterweight metallic 80.

 Ribs 82 provided symmetrically on the bottom of the body 60 make it possible to angularly limit the amplitude taken by the valve 68.

Claims (11)

RESELL ICAT IONS  1.- Detection and signaling device for regulating the level of a liquid in an engine, comprising a tank (1) comprising a first orifice (19), or upper supply orifice, connected to an inlet pipe liquid (9), and a second orifice (12), or liquid outlet orifice, tank inside which is disposed an element (21) mounted floating on said liquid, so as to move vertically upwards or downwards depending on the level of the liquid inside the tank (1), this element (21) being provided, at its upper part, with sealing means (25) intended, when the level of the liquid to the interior of the tank (1) reaches a given predetermined level, to close the aforesaid supply orifice (19), characterized in that the bottom (31) of the tank (1) comprises, under said float element (21 ), a first conductive element of the electric current (35) connected to external connection means (40) s to said tank (1), and a second element conducting the electric current (48), isolated from said first element (35), and which is connected to connection means (49) external to said tank (1), the second electric current conducting element (48) being able to be applied to the first electric current conducting element (35) by the weight of the float element (21) when the level of the liquid in the tank (1) drops below a predetermined threshold value.  2.- Device according to claim 1 characterized in that the first conductive element of the electric current (35) is adjustable along the longitudinal axis (yy ') of the tank (1).  3.- Device according to claim 2 characterized in that said first element conducting the electric current consists of a screw (35) arranged along the longitudinal axis (yy ') of the tank (1), which is screwed on the bottom (31) of said tank (1).  4.- Device according to any one of the preceding claims, characterized in that the second electrically conductive element (48) consists of a deformable metal strip, disposed between said first conductive element (35) and said float element (21).  5.- Device according to any one of the preceding claims, characterized in that at least one of the above conductive elements (35,44) is fixed to the tank (1) by means of an insulating element (33,42 ).  6.- Device according to claim 5 characterized in that the insulating element consists of a sleeve (33,42).  7.- Device according to any one of the preceding claims, characterized in that the tank (1) comprises, on its internal face, longitudinal ribs between which the float element (21) is slidably mounted.  8.- Device according to any one of the preceding claims, comprising a body (60), provided at its upper part with a liquid inlet orifice (63) connected to the liquid inlet pipe (9) and , at its lower part, a liquid outlet orifice (65) connected to said first orifice (19), inside which a valve (68), symmetrical with respect to a vertical plane, is mounted movable, characterized in that the valve (68) is mounted oscillating about a horizontal axis (66), and is provided, at its base, with at least two housings (70), arranged symmetrically with respect to said vertical plane of symmetry and forming with this an angle (a), inside which are respectively movably mounted at least two shutter elements (72), the weight and dimensions of each shutter element (72) and of the valve (68), the positioning of the center of gravity (G) of the latter, being such that, one of the shutter elements (72) comes lo ger in said outlet (65) when said body (60) is inclined at an angle at least equal to the angle (a) relative to the vertical, and that, the shutter element (72) being housed in said outlet (65), the valve (68) exerts on said shutter element (72) a return force such that it is sufficient to extract the latter from the outlet (65) when said body ( 60) returns to a substantially vertical position.  9.- Device according to claim 8 characterized in that the shutter elements consist of balls (72), in particular steel balls.  10.- Device according to one of claims 8 and 9 characterized in that the valve (68) is made of a liquid-resistant plastic material whose flow is to be controlled, said valve (68) comprising a metal counterweight (80) , in particular lead, on which the valve (68) is molded, the weight of said counterweight (80) being a function of the importance of the desired return torque.  11.- Device according to any one of claims 8 to 10 characterized in that stops (82) for angular limitation of the amplitude capable of being taken by the valve (68) are arranged on either side of the plane of symmetry of the body (60).