EP0113278A1 - Submersible pump device, especially for the fuel supply of a burner - Google Patents

Abstract

1. An arrangement for supplying a receiving member with liquid originating from a supply chamber comprising : - a blind body (19) prevented from rotation and mounted so as to be able to slide on a rotatable driving shaft (16) ; - a cam mechanism (16A, 19A) disposed between the body and the shaft to produce, in co-operation with a spring acting on the body, an alternating movement of low amplitude of the body on the shaft, in response to the rotation of the shaft ; - the blind body (19) and the shaft defining between them a pumping cavity (24), the volume of which varies as a result of the action of the cam mechanism when the shaft rotates, and which communicates with a port (23) provided on the shaft, said port (23), when the shaft rotates, being alternately positioned in relation with a suction opening (21), and a delivery opening (22), made in the blind body, characterised in that it comprises a supply chamber (18), connected with the suction opening (21), and in which the blind body (19) is housed, while a seal (25) is mounted between the rotatable shaft and a fixed wall (26) of the supply chamber, and in that the delivery opening (22) is connected to a manifold (31, 32) ending outside the supply chamber.

Description

The present invention relates to a device for supplying liquid to a receiving member, comprising a submerged pump and intended in particular but not exclusively for supplying a burner with liquid fuel.

Patent FR 2 448 054 describes a pump, in particular for liquid fuel, comprising a blind body immobilized in rotation and mounted so as to be able to slide back and forth on a rotary shaft, for example directly on the shaft of an engine. A cam mechanism arranged between the body and the shaft, for example constituted by the machined end of the shaft, produces the alternating rectilinear movement of the body along the axis of the shaft and therefore the cyclic variation of the volume of a pumping chamber defined by the end of the shaft and the interior of the blind body.

This extremely simple pump is well suited to the low liquid flow rates to which users are oriented for reasons of economy.

However, it has the drawback of requiring between the drive shaft and the open end of the blind body a dynamic type seal subject not only to the stresses resulting from the rotation of the shaft, but also to the alternating stresses produced-- by the sliding of the body back and forth on the tree. It is understood that the fatigue of the seal is high and induces a non-negligible risk of leakage.

In addition, such a pump displaces very low fuel flow rates, unlike conventional pumps with oversized flow and recycling; the supply of air bubbles to the pump is therefore more troublesome and can cause the burner to go out.

The object of the invention is in particular to remedy the aforementioned drawbacks of pumps of the type described and to create a liquidc supply device which is reliable, inexpensive and compact.

• - un corps borgne immobilisé en rotation et monté de manière à pouvoir coulisser sur un arbre moteur rotatif,
• - un mécanisme à came disposé entre le corps et l'arbre pour produire en coopération avec un ressort agissant sur le corps un mouvement de va et vient de celui-ci sur l'arbre en réponse à la rotation de l'arbre,
• - le corps borgne et l'arbre définissant entre eux une cavité de pompage dont le volume varie sous l'effet du mécanisme à came quand l'arbre tourne et qui communique avec une lumière prévue sur l'arbre et mise elle-même en relation alternée, quand l'arbre tourne, avec un orifice d'aspiration et un orifice de refoulement ménagés dans le corps borgne.

It relates to a device serving to supply liquid to a receiving member from a supply chamber and comprising:

• - a blind body immobilized in rotation and mounted so as to be able to slide on a rotary motor shaft,
• - a cam mechanism arranged between the body and the shaft to produce, in cooperation with a spring acting on the body, a movement back and forth thereof on the shaft in response to the rotation of the shaft,
• - the blind body and the shaft defining between them a pumping cavity whose volume varies under the effect of the cam mechanism when the shaft rotates and which communicates with a light provided on the shaft and put itself in relation alternating, when the shaft rotates, with a suction port and a discharge port formed in the blind body.

The device according to the invention comprises a supply chamber, connected to the suction orifice and in which is housed the blind body, while a seal is mounted between the rotary shaft and a fixed wall of the supply chamber, and that the discharge orifice is connected to a tube terminating outside of the latter.

The life of the seal is thus improved by the fact that it is only subjected to the low load of the liquid in the supply chamber and that it does not have to bear stresses due to the alternating sliding of the body. on the rotating shaft. In addition, the immersion of the vibrating body in the chamber allows wide manufacturing tolerances especially for the body since the leak fluid between the body and the shaft is no longer a nuisance and contributes to the lubrication of the body-shaft bearing.

Preferably the supply chamber is mounted on the drive shaft in the form of a supply sub-assembly including the blind body and a degassing device. The latter may advantageously comprise a rigid or flexible tube connecting the suction orifice of the blind body to the interior space of the chamber, the tube having a liquid drawing orifice and at an upper level an opening allowing progressive elimination air bubbles reaching the room.

This degassing device constitutes another important aspect of the present invention, and can moreover be used in a supply chamber which would not contain the pumping device internally, a pump of a different kind would be used.

In the particular case of supplying fuel to a burner, the chamber may be formed in one piece with a flange or with the motor or fan casing. It can of course be engaged with the seal on the motor shaft to be removably attached to the flange or to the casing. In both cases, it is desirable to provide access to the interior of the room.

The pump body can be immobilized in rotation by the discharge hose connecting the body discharge orifice to an outlet connector of the chamber and / or by a suction hose connecting the body suction orifice to the 'interior space of the room; the suction hose can of course constitute the degassing tube envisaged previously. The design of the supply device is thus simplified.

• - la figure 1 représente schématiquement une coupe axiale d'un brûleur équipé du dispositif d'alimentation conforme à l'invention ;
• - la figure 2 montre une coupe schématique agrandie du dispositif de la figure 1 ;
• - la figure 3 représente le dispositif en coupe transversale selon le plan III-III de la figure 2, et
• - la figure 4 représente en vue agrandie les éléments de la pompe des figures 2 et 3.

Other characteristics and advantages of the invention will appear on examining the detailed description which follows and the attached drawings, in which:

• - Figure 1 schematically shows an axial section of a burner equipped with the supply device according to the invention;
• - Figure 2 shows an enlarged schematic section of the device of Figure 1;
• FIG. 3 represents the device in cross section along the plane III-III of FIG. 2, and
• - Figure 4 shows in enlarged view the elements of the pump of Figures 2 and 3.

FIG. 1 shows a burner 10 comprising a device 11 for supplying liquid fuel, a fan 12 of known type with an outer casing 13, a combustion head 14 and regulating and control members 15.

An electric motor of axis X-X of which only the shaft 16 and its ball bearing 13A has been indicated makes it possible to actuate the fan 12 and a pump 17 of the supply device 11.

As best shown in Figures 2 and 3, the device 11 has a fuel chamber 18 and - a - blind body 19 slidably mounted on the end of the shaft 16. The body 19 can be immobilized in rotation by cooperation of a post and a complementary mortise provided on the body and on a fixed part of the chamber 18; however, it is preferably prevented from rotating by connection hoses and by a return spring which will be described later.

The body 19 is movable on the shaft 16 in an alternating translation of small amplitude by means of a cam mechanism constituted either by a cam flange formed on the shaft, or by a cam machined at the end shaft and cooperating with an eccentric stop provided inside the body. Such arrangements have been described in patent FR 2 448 054.

However, in the preferred embodiment of the present invention, there is provided (FIG. 4) a stop machined at the end of the shaft 16A, which cooperates with an inclined cam surface 19A provided internally at the bottom of the blind body 19, during its molding. made of synthetic material.

In this way, the flow rate of the pump can be very simply adapted by exchange of the blind body 19, the shaft 16 remaining the same.

When the drive shaft 16 rotates, the cam mechanism produces the comings and goings of the blind body 19 on the shaft in cooperation with a weak return spring 20 interposed between the body and a fixed wall 18A of the supply chamber.

The blind body 19 has (FIG. 3) a suction hole 21 and a discharge hole 22 which are substantially opposite; these orifices are connected alternately during rotation of the shaft with a lumen 23 of the shaft itself open on a pumping cavity 24 of cyclically variable volume, formed between the body and the shaft.

According to the invention, the blind body 19 is housed in the supply chamber 18 and its suction orifice 21 communicates with the volume of liquid contained in the chamber under normal pumping conditions while a seal ( O-ring 25 and / or lip seal 25A) is disposed between the rotary shaft 16 and a fixed wall 26 of the supply chamber. It will be easily understood that the seal 25 only supports the stresses due to the rotation of the shaft, as well as the low pressure of the liquid in the chamber. In addition, the body 19 can now be manufactured with a wide tolerance since leaks from liquid return to the chamber while lubricating the bearing; finally, the spring 20 can be lightened as a result of the reduction in the weight of the body freed from the seal, the stop 17A (FIG. 4) of the spring therefore also being able to be lightened.

A flexible tube 27 located in the chamber 18 is connected to the suction nozzle 21. It has an opening 29 at its free end. A calibrated orifice 28 is provided in the tube 27 or better in the suction nozzle 21. The normal level of liquid in the chamber is designated by h ₁ . The opening 29 is located higher than the calibrated orifice 28, and higher than the level h ₁ . Chamber 18 has an inlet connection 30, fitted with a filter 30A. whose opening is above the level of the pump.

An at least partly flexible tube 31 is connected on the one hand to the discharge orifice 22 of the blind body, on the other hand to an outlet connector 32 of the chamber 18.

It should be noted that the hoses 27, 31 help to immobilize the blind body 19 in rotation while allowing its alternating sliding of small amplitude on the shaft. The hoses are for example in abutment against the inner wall of the supply chamber. It should be noted that the rupture of one of the hoses does not have the effect of an external leakage of the liquid.

• En régime établi et lorsqu'il n'y a pas d'arrivée d'air au raccord d'entrée 30, la pompe volumétrique 17 assure le même débit de liquide d au raccord 30, à l'orifice calibré de puisage 28, à l'orifice d'aspiration 21 ; l'orifice 28 est calibré de sorte que le niveau du liquide dans la chambre se stabilise à la hauteur h₁ assurant une charge suffisante pour faire passer le débit.

The degassing supply device described operates as follows:

• In steady state and when there is no air supply to the inlet connection 30, the positive displacement pump 17 ensures the same flow of liquid d at the connection 30, at the calibrated orifice 28, the suction port 21; the orifice 28 is calibrated so that the level of the liquid in the chamber stabilizes at the height h ₁ ensuring a sufficient charge to pass the flow.

When a certain quantity of air suddenly arrives at the connection 30, the level of the liquid drops to a level h ₂ indicated in dashes in FIG. 2, this level being insufficient to ensure the flow d at the orifice 28. The flow with the suction orifice 21 being unchanged, the volumetric compensation is effected by suction of air through the opening 29 and the tube 27. The air is therefore associated with the liquid in the form of micro-bubbles sucked into the orifice 21 at each pumping cycle. The volume between the calibrated orifice 28 and the lumen 23 is less than the displacement of the pump and thus ensures perfect regularity.

The excess air in the supply chamber 18 is then progressively canceled by sending micro-air bubbles with the fuel to the burner, without causing the latter to shut down unexpectedly. As previously indicated, this degassing device can be used with a pump 17 different from that described above, submerged or not.

Furthermore, it can be seen that the presence of the seal 25 in a fixed wall 26 of the chamber 18 makes it possible to ensure constant wetting of the pump 17. The blind body 19 constitutes (where appropriate with the flexible 27 and the flexible 31) an interchangeable component allowing a change of flow. Indeed, to change the flow rate, it will suffice to replace a component provided with a body 19 with cavity 24 and calibrated orifice 28 by a component with cavity, inclined cam surface and calibrated orifice dimensioned differently. This can be done easily after opening the cover 18A of the chamber 18.

It goes without saying that modifications can be made to the embodiment described without departing from the scope of the invention.

Claims (9)

1. Device for supplying liquid to a receiving member from a supply chamber comprising: - a blind body immobilized in rotation and mounted so as to be able to slide on a rotary motor shaft, - a cam mechanism arranged between the body and the shaft to produce in cooperation with a spring acting on the body an alternating movement of low amplitude of the body on the shaft, in response to the rotation of the shaft, - the blind body and the shaft defining between them a pumping cavity whose volume varies under the effect of the cam mechanism when the shaft rotates and which communicates with a light provided on the shaft and puts itself in relation alternating, when the shaft rotates, with a suction port and a discharge port formed in the blind body,
characterized by the fact that it comprises a supply chamber (18), connected to the suction orifice (21), and in which the blind body (19) is housed, while a seal ( 25) is mounted between the rotary shaft and a fixed wall (26) of the supply chamber, and that the discharge orifice (22) is connected to a tube (31, 32) terminating outside the feed chamber. 2. Supply device according to claim 1, characterized in that the supply chamber (18) comprises a degassing device interposed between an inlet connection (30) of the chamber and the suction orifice ( 21). 3. Feeding device according to claim 2, characterized in that the degassing device comprises a tube (27) connecting the orifice suction (21) inside the supply chamber, the tube (27) having at a predetermined level an orifice (28) for drawing off liquid and at a level higher than that of the orifice (28) and that of the liquid in the chamber, an opening (29) allowing the elimination of air bubbles reaching the supply chamber (18). 4. Supply device according to one of claims 1 to 3, characterized in that the supply chamber (18) is mounted on the drive shaft (16) as a supply sub-assembly including the body blind (19). 5. Feeding device according to claim 4, characterized in that the feed chamber (18) includes the seal (25). 6. Feeding device according to one of claims 1 to 5, characterized in that the blind body (19) is immobilized in rotation by at least one connection hose (31). 7. Feeding device according to claim 6, characterized in that at least one connection hose (27) bears against the inner wall of the feed chamber (18). 8. Supply device according to one of claims 1 to 7, characterized in that the tube (27) connected to the supply orifice (21) is flexible. 9. Liquid fuel burner comprising the supply device defined by one of claims 1 to 8.

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