FR2586064A1 - METERING PUMP - Google Patents

Abstract

THE INVENTION CONCERNS A DIAPHRAGM MEASURING PUMP, WITH TWO SUCTION AND DISCHARGE VALVES 53-59, RESPECTIVELY MOUNTED ON A SUPPORT 42 INSIDE THE PUMP BODY. EACH VALVE CONSISTS OF A FLAT AND THIN 54-60 PLATE MOUNTED WITH INTERPOSITION OF A SEAL 55-61 IN A HOUSING PROVIDED IN THE SUPPORT, THE HOUSINGS OF THE TWO VALVES BEING OPEN TO THE PUMPING VOLUME RESPECTIVELY FOR THE SUCTION VALVE AND TO COLLECTOR CAPACITY FOR THE DISCHARGE VALVE, THE PADS OF THE TWO VALVES BEING EACH PRESSING AGAINST A FIRST SIDE OF A THIN WASHER 56-62 MADE OF AN ELASTIC MATERIAL, IMMOBILIZED AGAINST THE SUPPORT AND PROVIDED WITH HOLES 57 -63 OF COMMUNICATION RESPECTIVELY WITH THE PUMPING VOLUME AND THE COLLECTOR CAPACITY, EACH WASHER BEING ASSOCIATED ON ITS FACE OPPOSED TO THE PLATE OF THE VALVE HAS A LAYER OF LOW THICKNESS 58-64 OF AN ELASTIC MATERIAL WITH OPEN POROSITY.

Description

The present invention relates to a metering pump,

  particularly applicable in the chemical industry for the supply of very low flow of liquid products, taken from a reserve and returned to a user device. We already know many achievements of pumps

  low flow dosing machines, where the movement of

  quide through the pump is effected by the movement, in an enclosure comprising a suction valve and a discharge valve operating alternately, a flexible or semi-rigid membrane, sealingly closing one side of this pregnant and whose movements

  are controlled by a mechanical or electro-magnetic system

  tick. The successive pressures and overpressures created in the chamber of the pump by the displacement of the membrane thus cause, successively, the suction

  of a given volume of liquid through the suction valve.

  at the end of the race the closing of this valve then, the

  movement of the membrane reversing, the opening of the

  fart of repression and the expulsion of the volume of liquid previously sucked. Knowing the volume of the chamber, it is thus possible, by adjusting the speed or rate of movement of the diaphragm, to provide at the outlet of the pump beyond the discharge valve a precisely determined flow rate which can moreover be adjusted in a wide

  range of values at the discretion of the user.

  However, in the known embodiments of this type, it is generally necessary to oversize the pump body to allow, in all circumstances, and even with very low flow rates, a safe self-priming of the pump. Indeed, the space required to mount the valves and their seat in the pump body does not usually reduce beyond a certain limit the residual volume of the pump, remaining beyond the maximum discharge stroke of the membrane. As a result, this residual volume remains generally too large vis-à-vis the maximum pumping capacity and does not, in all circumstances, to ensure automatic self-priming of the device. To mitigate these

  disadvantages, conventional solutions consist of

  see with the pump, a number of buffer tanks that make the implementation of the installation more complex

  and above all, significantly increase its cost price.

  However, users, especially in the chemical industry, may have to use the same metering pump for different successive liquids, with the need then, according to the solutions already known, to proceed to

  each time with a pump re-priming, long and difficult

  cult. Moreover, oversizing the pump necessarily increases its cost price and does not allow it to be supplied as a simple accessory

  marketed with the liquid product constituting the

main course.

  The subject of the present invention is a metering pump which makes it possible to avoid these disadvantages by ensuring, even for a very low flow rate, for example less than one liter per hour, an instantaneous and self-priming of the apparatus, it can also be of dimensions

  very low, which allows a significant cost price

  decreased compared to comparable conventional solutions. For this purpose, the metering pump considered comprises a pump body, a part of which is constituted by a control membrane sealingly attached to the pump body and moved back and forth under the effect of a control member. control, so as to periodically reduce and increase a pumping volume delimited between the pump body and the membrane and two valves, respectively suction and discharge, joined together for one A inlet duct and the other To an outlet pipe i of a liquid to be pumped, these valves being mounted in a support, integral with the pump body and separating the pumping volume communicating with the inlet conduit via the

  suction valve and collector capaeity

  as for the pumping volume via the discharge valve and connected to the liquid outlet duct, is characterized in that each valve is constituted in a manner known per se, a flat plate and thin mounted

  with the interposition of a seal in a box

  provided in the support, the housings of the two flaps being open respectively to the pumping volume.

  for the suction valve and to the collector

  for the discharge valve, the plates of the two flaps being each bearing against a first

  face of a thin ring made of an elastic, immovable

  bilized against the support and equipped with communication holes

  respectively with the pumping volume and the capacity

  collector city, each washer being associated on its opposite side to the plate of the flap to a layer of

  thin layer of an elastic material with open porosity

  you. Thanks to these arrangements, the pumping volume on the one hand, the collecting capacity on the other hand, on each side of the valve support, contain a set formed by a thin elastic washer against which is applied

  a layer of porous foam, so that the

  quide sucked on one side, pushed back the other, crosses each beat of the membrane the corresponding set

  from one side of the suction valve and out

  both of the discharge valve. As regards the pumping volume in particular, the membrane comes to the end of the stroke corresponding to the minimum dimensions of the pumping volume in direct contact with the foam layer, which thus reduces the available residual volume. In addition, the capillary effect created by the porous foam and the distribution of the liquid pressure created by the washer

  associated, allows in all circumstances the

  priming the pump, even for very low liquid flow rates or liquid pumping heights

notables.

  Advantageously and according to a particular characteristic of the invention, the inlet duct communicates with the housing of the suction valve and the pumping volume communicates with the housing of the discharge valve by

  bores machined in the support.

  According to another particular characteristic of the metering pump according to the invention, the layer of elastic material is constituted by a polyurethane foam or

analog, open cell.

  Preferably, the thin washers disposed

  in the pumping volume and capacity

  collector against suction and discharge valves

  are made of rubber and

  by their periphery between on the one hand in the pumping volume, the support and a shoulder provided in

  the pump casing and secondly in the collec-

  between the support and a closing lid

putting this capacity.

  According to another particular characteristic of the in-

  vention, the control membrane has a generic shape

  of revolution around an axis perpendicular to

  flaps and consists of a plastic material

  injected membrane, this membrane comprising an outer collar provided with a housing for a seal, applied against a bearing surface of the pump body, the diaphragm

  being immobilized on it by means of a counter

flange.

  According to another characteristic also, the counter

  flange is the support of an electromagnet, comprising a carcass of magnetic sheets provided with an electric winding and adapted to attract against one of its faces extending perpendicularly to the axis of the membrane a flat magnetic piece, integral with a sliding rod axially passing through the winding and a passage formed in the counter-flange opposite the diaphragm, this rod being connected to the center of the latter along its axis by a connecting end.

  Advantageously, the sliding rod comprises a plate

  support plate of a return spring of the magnetically

  than flat, opposing the attraction of it by the e-

  the electromagnet, this spring being held against a range

  arranged opposite on the counter-flange.

  Finally and according to another characteristic also, the closing cap of the collecting capacity is extended by a threaded plug, provided with an axial passage through which the liquid supply conduit passes, this plug being able to be secured by screwing with the 'end

  a can or reserve of the liquid to be pumped.

  Other characteristics of a metering pump established in accordance with the invention will still appear throughout

  the following description of an exemplary embodiment, given

  indicative and not limiting, with reference to the

  attached in which: Figures 1 and 2 are views respectively of profile and scale face, a metering pump according to the invention. 25. Figure 3 is a cross sectional view of the

  metering pump considered, represented on a larger scale

  in order to better distinguish the detail from the realization of

  its different constituent parts.

  Figure 4 is a detail view on a larger scale, illustrating the support of the valves of the metering pump. Figure 5 is a partial perspective view of a detail of the embodiment of the valves and various organs

  associated with them according to the invention.

  35. Figure 6 is a partial cross-sectional view on a larger scale also along the line

VI-VI of Figure 3.

  As shown in Figures 1 and 2, the pump in question is mainly composed of a pump body 1 of plastic, on which is mounted a protective bell 2 of plastic or other. This bell 2, intended as will be seen below, to contain a control electromagnet of the pump, has a lateral extension 3, clamped at its end by means of a collar 4 sealing on electrical connection son 5 of

the electromagnet.

  The pump body 1 is associated with a cover 6, provided at its lower end with a plug 7 traversed axially by a conduit 8 for suction of the liquid to be pumped, connected directly to the inside of the pump body 1. exhaust duct of the same liquid discharged by the pump is designated under the reference 9, the latter being directly connected to the lid 6 applied against the body 1. The end cap 7 is intended in particular to allow the direct connection of the pump on the end of a can 10 or reserve

  analogous, liquid to pump (Figure 2).

  FIGS. 3, 4 and 5 illustrate in more detail the construction of the pump in question, and in particular the

  its valves and the means associated with them.

  In FIG. 3, it can thus be seen that the body of the pump 1 comprises a transverse flange 11 against which a flange 12 internally fitted to the corresponding end of the protective bell 2,

  this flange 12 being clamped between the flange 11 and a counter

  flange 13 applied against it and assembled therewith in the manner to be described in more detail

  in the following, with reference to FIG.

  flange 13 comprises a first cylindrical flange 14 against the upper end 15 of which is to be applied the end face 16 of an electromagnet 17 whose embodiment detail is of little importance to the invention and is in itself classic. This electromagnet 17 comprises in particular an electric coil 18 joined directly inside the bell 2 to the connections 5, and presents axially a bore 19 internally provided with bearings 20 and 21, allowing the clearance-free movement inside this bore 19 a sliding rod 22. The latter has at its end directed towards the bottom of the bell 2, a threaded extension 23 freely traversing a hole in the center of a magnetic piece 24 forming a magnet, able to be attracted by the electromagnet 17 when the latter is energized. The piece 24 is immobilized against a shoulder 25 formed at the end of the rod 22 and is locked thereon by a washer 26 and a nut

  27 engaged on the threaded extension 23.

  At its opposite end, the rod 22 rests on a transverse plate 28, itself serving as a stop at the end of a helical spring 29 mounted -coaxially to the sliding rod 22, this spring 29 being housed at the inside a second cylindrical flange 30 formed in the counter-flange 13 inside the first collar 14. The spring 29, immobilized between the central portion 31 of the counter-flange 13 and the plate 28, allows exert on the latter and consequently on the rod 22, an opposing force opposing the attraction of the electromagnet 17 vis-à-vis the magnetic part 24, and in particular in the absence of power electrical coil 18, pushing this piece in the position shown in the drawing. On the other hand, when the coil is energized, it draws toward the left of the drawing the part 24 whose attraction stroke is

  schematized in the figure by the distance "e".

  Between the counter-flange 13 and the flange 11 of the pump body 1 is disposed a semi-rigid control membrane

  32, made of a suitable preformed plastic material.

  This membrane 32 has an end flange 33, trapped between the flange 11 and the counter-flange 13 and has an external groove 34 for the housing of an O-ring seal 35. In its central portion 36, the membrane 32 comprises a tip 37 disposed in the extension of the rod 22, this endpiece 37 having a hollow profile threaded internally and in which is screwed a threaded portion 38 provided at the corresponding end of the rod 22. An O-ring 39 is mounted between the semi-rigid membrane 32 and the corresponding face of the counter-flange 14 to avoid, in the maximum displacement position the rod 22 under the effect of the electromagnet, a damaging crushing of the membrane. The suction duct 8 penetrates inside the pump body 1 through a seal 40 and opens into a housing 41 in which is mounted a support 42 for the valves of the pump, as shown in more detail 4. The discharge pipe 9 penetrates for its part into the cover 6 through a seal 43 subjected to the action of a washer 44, itself held in place by a cover 45 blocked by means of a screw 46 on a bearing surface 47 provided on the outside of the body 1, the seal between the lid 6 and the body 1 being made to the assembly by means of a seal

48.

  According to the invention, the support 42 of the valves of the pump 1 delimits inside the assembly constituted by the pump body 1 and the cover 6, two separate regions respectively constituting the pumping volume 49 between the support and the control membrane 32 and a collecting capacity 50 o collects the discharged liquid, between the support 42 and the cover 6. The support 42 (Figure 4) has two pipes respectively 51 and 52, the first of which putting in communication the housing 41 opens the suction duct 8 with the pumping volume 49, while the second communicates the same volume 49 with the

collecting capacity 50.

  The support 42 further includes, towards the end of the pipes 51 and 52 opening for one in the pumping volume 49 and the collecting capacity 50 for the other, two respectively suction valves 53 and discharge valves 59, of which the detail is also illustrated

  in the perspective view of Figure 5. The check valve

  Piration 53 consists of a plate 54 of a rigid material, stainless steel or the like, against which is applied an O-ring seal 55. The wafer 54 is supported in its face facing the pumping volume 49 against a washer 56 rubber or other

  thin material of similar thickness, with

  towards its surface a set of communication holes 57.

  On the opposite side of the washer 56 is also

  layer 58 of a material having a structure

  open and porous structure, advantageously consisting of a

  other washer made of polyurethane foam or the like.

  The discharge valve 59, mounted at the opposite end of the pipe 52 towards the collecting capacity, likewise has a plate 60, a seal 61, a rubber washer 62 whose surface is pierced with a set of communication holes 63 and a complementary piece or washer made of foam of

  polyurethane 64, mounted against the lid 6.

  The metering pump further comprises, as illustrated in Figure 6, means for easy and quick assembly of its main parts by means of a single fastener. For this purpose, the counter-flange 13 is associated with an anchor piece 65 having a flange 66 engaged in a housing 67 of the end face 16 of the electromagnet 17. This piece 65 has a threaded portion 68 receiving the end of a stud 69 which thus makes it possible to rigidly assemble the lid 6, the body of

  pump 1, counter flange 13 and bell 2.

  Returning again to FIG. 3, it can finally be seen that the cover 6 extends in the direction of the suction duct 8 by a flange 70 traversed by this duct and provided in its upper end with a flange 71, allowing both the hooking and free rotation of the threaded plug 7, the latter having an internal thread 72 cooperating with the end 73 of the can or reserve of liquid 10, in which the end of the conduit 8 is immersed. An orifice 74 allows the communication with

  the outside atmosphere of the reserve.

  In operation, the dosing pump shown, mounted as illustrated in the drawings, is connected to a

  reserve or can 10 of a liquid product to be pumped

  than. The suction duct 8 penetrates below the level of the

  liquid, so that the power up of the

  magnet-magnet 17 by means of a control device (not shown) successively providing power and

  power cut, allow, at a determined rate of

  born, a movement movement back and forth of the membrane 32. The liquid sucked through the conduit 8 and enters the housing 41 and through the pipe 51, is conveyed to the suction valve 53. Under the effect of depression created by displacement

  of the membrane 32, this valve opens, allowing the introduction

  duction of a suitable quantity in the volume of

  page, after crossing the washer 56 by its holes 57 and the foam layer 58. When the movement of the rod 22 is reversed, the amount of liquid thus sucked is discharged through the pipe 52, the valve 53 being previously closed. Simultaneously, the second valve 59 opens, the liquid then being forced through the washer 62 and the holes 63 thereof to the foam layer 64 and the collecting capacity 50, before being released by

the evacuation pipe 9.

  In this way a metering pump is

  simple, particularly susceptible to be easily miniaturized

  See. As an indication, the diameter of joints 55 and 61

  may be between 1.15 mm and 3.15 mm, that of

  farts 54 and 60 close to 4 mm, the rubber washers

  & 6064 located behind these having a maximum diameter of 14 mm with a thickness of the order of millimeters. The layers of foam disposed behind the rubber washers have a thickness of not more than 2 mm. One of the main advantages of the metering pump thus achieved is its self-priming regardless of the flow required, the rate of movement of the membrane, and the nature of the liquid to be pumped. Furthermore, the very simple realization of the pump and its relatively limited number of parts, can significantly lower its cost and so that it can generally be a simple accessory marketed with cans or liquid reserves considered, by providing the purchaser with an advantage

particularly appreciated.

  In the foregoing, only one embodiment of the invention has been described; it goes without saying that this one is not limited to this one but embraces on the contrary all the variants. In particular, we could without

  out of the scope of the invention consider for the realization

  washers or porous foam layers of other materials more suited to the specific nature of the

each liquid to be pumped.

Claims (8)

  1 - Metering pump, having a pump body (1)   part of which consists of a control diaphragm   of (32) sealingly attached to the pump body and reciprocated by a control member (17) to periodically reduce and increase a pumping volume (49) delimited between the pump body and the diaphragm and two valves (53-59), suction and discharge respectively, joined together for   one to an inlet duct (8) and for the other to an   outlet pipe (9) of a liquid to be pumped, these valves being mounted in a support (42) integral with the pump body and separating the pumping volume communicating with the inlet pipe via the suction valve (53). ) and a collecting capacity (50) communicating with the pumping volume via the discharge valve (59) and connected to the liquid outlet duct, characterized in that each valve is constituted, in a manner known per se,   a flat and thin plate (54-60) assembled with   position of a seal (55-61) in a housing provided in the support, the housings of the two valves being respectively open towards the pumping volume   for the suction valve and to the collector   for the discharge valve, the plates of the two flaps being each bearing against a first   face of a thin washer (56-62) of an elastic material   that, immobilized against the support and provided with holes (57-   63) respectively with the pumping volume and the collecting capacity, each washer being associated on its face opposite the plate of the valve to   a thin layer (58-64) of an elastic material tick with open porosity.   2 - metering pump according to claim 1, characterized   in that the inlet duct (8) communicates with the suction valve housing and the pump volume (49) communicates with the discharge valve housing.   by bores (51-52) machined in the support (42).   3 - metering pump according to one of claims i or   2, characterized in that the layer of elastic material (58-64) is constituted by a polyurethane foam or the like, with open cells.   4 - metering pump according to one of claims 1 or   2, characterized in that the thin washers (56-62) respectively arranged in the pumping volume (49) and   in the collecting capacity (50) against the check valves   Suction and discharge, are made of rubber.   - Metering pump according to one of claims 1 or   2, characterized in that the thin washers are immo   bilized respectively by their periphery between on the one hand in the pumping volume (49), the support (42) and a shoulder provided in the pump body and on the other hand in the collecting capacity (50) between the support and a   closure cover (6) defining this capacity.   6 - Dosing pump according to any one of the claims   cations 1 to 5, characterized in that the control membrane (32) has a general shape of revolution about an axis perpendicular to the planes of the valves and is constituted by an injected plastic material, this membrane comprising an outer collar (32) provided with a housing for a seal (34) applied against a bearing surface of the pump body, the diaphragm being   immobilized thereon by means of a counter-flange (13).   7 - metering pump according to claim 6, characterized   characterized in that the counter flange constitutes the support of an electromagnet, (17) comprising a carcass made of magnetic sheets, provided with an electric winding (18) and   apt to attract against one of its faces extending   perpendicular to the axis of the membrane, a magnetic part   plate (24) integral with a sliding rod (22) passing through   axially the winding and a passage formed in the counter flange (13) facing the membrane, (32) this rod being connected to the center thereof along its axis by a connecting end (38).   8 - metering pump according to claim 1, characterized   in that the sliding rod (22) comprises a   support pillar (28) of a return spring (29) of the flat magnetic piece (24) opposing the attraction thereof by the electromagnet, this spring being held against a bearing (31) provided on the opposite side on the counter flange (13).   9 - metering pump according to claim 5, characterized   characterized in that the closure cap (6) of the collector capacitor 10 is extended by a threaded plug (7) provided with an axial passage through which the liquid supply duct (8) passes, this plug being adapted to be secured by screwing with the end of a container (10) or a reserve liquid to pump.