EP2638287B1 - Dosing device for proportionally dosing an auxiliary liquid into a main liquid - Google Patents

Description

The invention relates to a proportional proportioner of an auxiliary liquid in a main liquid, a metering device of the type comprising a metering body with a main liquid inlet and an outlet, a hydraulic motor housed in the body, actuated by the main liquid, and connected to a plunger for driving in a reciprocating rectilinear motion, the plunger moving in a first chamber open at a first end remote from the hydraulic motor and opening at a second end in the interior volume of the body of a metering device containing main liquid, the plunger providing suction during a stroke away from the first end of the chamber, the plunger being able to exit the first chamber at the end of the forward stroke, a valve being provided for allow the passage of the liquid to the interior volume of the body beyond a certain pressure in the first chamber, when of the race back.

A proportional proportioner of this type is known in particular according to the patent EP 0 255 791 B1 . Such a proportional metering device operates without electricity, operated only by the main liquid and allows a product injection, constituting the auxiliary liquid, into the main liquid which is generally water under a relatively low inlet pressure.

Many known proportional metering devices mix the main liquid and the auxiliary liquid in the metering body so that the metering body outlet provides the mixture. In some cases, especially when the auxiliary liquid is aggressive vis-à-vis the elements located inside the metering body, or for applications where the reaction between the metered product and the motor product leads to calcifications that can wear prematurely the doser, it is desirable to avoid any introduction of the auxiliary liquid inside the metering body and ensure mixing downstream of the metering body.

The patent EP 0 885 357 B1 , of the applicant company, proposes a solution to this problem, involving an expandable bellows. This solution is effective, but involves a significant modification of the metering pump.

The object of the invention is, above all, to provide a proportional doser which avoids the entry of the auxiliary liquid into the body of the doser and ensures the mixing of the two liquids at the downstream outlet of the doser, thanks to simple modifications of a conventional doser , allowing an easy adaptation, with an interest of modularity. It is desirable further that the proportional proportioner, while ensuring mixing at the downstream outlet, allows adjustment of the metered quantity.

According to the invention, a proportional doser of the kind defined above is characterized in that it comprises a second chamber of variable volume limited by a membrane subjected to the pressure prevailing in the first chamber, the second chamber comprising a suction port for the auxiliary liquid and a discharge port of the auxiliary liquid, this discharge port being connected by a pipe to an injection chamber located downstream of the outlet of the metering body to ensure mixing of the auxiliary liquid with the main liquid coming out .

The metering unit is advantageously arranged so that the pressure in the interior volume of the metering body is greater than the sum of the pressure in the injection chamber and the hydraulic head loss in the connection between the second chamber and the chamber. injection.

Preferably, a throttling member is provided downstream of the dispenser outlet, and upstream of the injection chamber to create a pressure drop, in particular sufficient to push back, the membrane at the end of suction, especially when the plunger exits the first chamber at the end of the race.

In the case of a pump configuration where the interior volume of the metering body communicates directly with the outlet, the pressure would be substantially the same in the interior volume of the body and at the outlet; the pressure drop created by the throttle member makes it possible to be assured of a sufficient pressure difference between the internal volume of the metering body and the injection chamber.

In the case of a pump configuration where the internal volume of the metering body communicates directly with the metering inlet, the engine pressure drop between the interior volume of the metering body and the outlet, if it is greater than the hydraulic head loss in the connection between the second chamber and the injection chamber, may be enough to push the membrane.

The second chamber is provided with a suction valve and a discharge valve; the settings of these valves as well as that of the throttling element are made to ensure proper operation of the dispenser.

Advantageously, the membrane defines, on the opposite side to the second chamber, a space communicating with the first end of the first chamber.

Preferably, the second chamber is located in a volume delimited by concavities facing a first cup and a second cup assembled, the periphery of the membrane being tightly sealed between the two assembled cups, the first cup being fixed to the metering body around the first end of the first chamber, while the second cup is provided with the suction port and the discharge port. The second chamber is thus formed between the membrane and the concavity of the second cup, the membrane being applied against the concavity of the first cup or that of the second cup.

Advantageously, the central portion of the membrane is integral with a rigid disk itself secured to an axial rod turned on the opposite side to the second chamber and slidable in a guide bore of the metering body, while leaving a passage for the liquid. Such guidance is only optional.

Preferably, the axial position of a liner delimiting the first cylindrical chamber, in which the plunger moves, is adjustable by means of a rotary ring.

The throttling element, located downstream of the outlet of the metering body, may be constituted by a cap provided with a cylindrical skirt with at least one slot, in particular longitudinal, installed on an inlet port of a sleeve connected to the outlet of the metering body, and whose axial position is adjustable.

The valve provided to allow the passage of the liquid to the interior of the body, beyond a certain pressure in the first chamber during the return stroke, may be a calibrated valve installed in a chamber provided at the end of the plunger.

According to one variant, the internal volume of the metering body communicates directly with the inlet of the metering device, so that the pressure drop of the motor between the interior volume of the metering body and the outlet contributes to pushing back the membrane. The pressure drop of the motor between the internal volume of the metering body and the outlet, if it is greater than the hydraulic pressure drop in the connection between the second chamber and the injection chamber, may suffice to push back the membrane, to which case the throttle can be avoided.

• Fig. 1 est une coupe verticale axiale, avec parties en extérieur, d'un doseur proportionnel selon l'invention, en phase montante d'aspiration du liquide auxiliaire.
• Fig. 2 montre, semblablement à Fig. 1, le doseur en phase descendante d'injection du liquide auxiliaire.
• Fig. 3 est une vue extérieure, en perspective, à plus petite échelle du doseur selon l'invention.
• Fig.4 est une coupe verticale axiale, avec parties en extérieur, d'une variante de doseur selon l'invention, en phase descendante.
• Fig.5 est un détail à plus grande échelle de la zone V de Fig.4, et
• Fig.6 est une coupe verticale axiale, avec parties en extérieur, d'une autre variante de doseur selon laquelle l'entrée de l'eau communique directement avec le corps de doseur.

The invention consists, apart from the arrangements described above, in a certain number of other arrangements which will be more explicitly discussed hereinafter with regard to exemplary embodiments described with reference to the appended drawings, but which are not in no way limiting. On these drawings:

• Fig. 1 is an axial vertical section, with external parts, of a proportional proportioner according to the invention, in ascending suction phase of the auxiliary liquid.
• Fig. 2 shows, similarly to Fig. 1 , the down-doser for injecting the auxiliary liquid.
• Fig. 3 is an external view, in perspective, on a smaller scale of the dispenser according to the invention.
• Fig.4 is an axial vertical section, with external parts, of a metering variant according to the invention, in a downward phase.
• Fig.5 is a larger scale detail of the V zone of Fig.4 , and
• Fig.6 is an axial vertical section, with external parts, of another variant of doser according to which the inlet of the water communicates directly with the metering body.

Referring to the drawings, in particular Fig. 1 , it is possible to see a proportional proportioner D of an auxiliary liquid in a main liquid which comprises a metering body 1, generally consisting of two parts, namely a base 1a and a lid 1b screwed on this base, having an inlet 2 of main liquid and an outlet 3. A hydraulic motor 4 of which only a lower part is visible in the drawing, is housed in the body 1. The geometric axis of this body 1 is generally arranged vertically and the motor 4 is located essentially in the lid 1b. The motor 4 is actuated by the main liquid and generally comprises a differential piston with hydraulic switching means at the end of races back and forth to reverse the direction of movement. Engines of this type are marketed by the applicant company. An example of such motors is described in the patent EP 1 971 774 B1 on behalf of the applicant company.

The hydraulic motor 4 is connected to a plunger 5, vertical according to the arrangement of Fig. 1 , to drive it in an alternating rectilinear motion. The plunger 5 moves in a first cylindrical chamber 6, delimited by a liner 6a, open at a first end 7 remote from the hydraulic motor 4. The chamber 6 opens at a second end 8 into the interior volume 9 of the metering body containing of the main liquid.

The plunger 5 is equipped, towards its lower end, with a seal 10 forming a valve, surrounding the plunger and housed in a groove 11. This groove 11 allows a clearance of the seal 10 during the race. discharge (descent) of the piston 5 to allow the passage of the liquid from the chamber 6 to the space 9 beyond a certain pressure.

The plunger 5, when it makes a forward stroke that moves away from the first end 7 of the chamber, creates a suction and, when it makes a return stroke to said first end 7, the piston 5 causes an increase in pressure in the chamber 6.

According to the invention, the doser D comprises a second chamber 12, of variable volume, limited by a membrane M subjected to the liquid pressure prevailing in the first chamber 6. The membrane M is flexible, deformable. The second chamber 12 is advantageously located in a volume delimited by the concavities opposite two hollow cups 13, 14 assembled removably. The cup 13, superior in the representation of Fig. 1 , is attached to the lower end of a column 15 of the metering body in which is located the liner 6a and the chamber 6. The membrane M is fixed in its central part to a rigid disk 16 integral with a rod axial 17, orthogonal to the disk, facing the chamber 6. The rod 17 is engaged, with sufficient radial clearance for the passage of the liquid, in a bore 18 of a nozzle 19 provided in the lower part of the column 15. The rod 17 has a sufficient length to guide the disc 16 and the membrane during the movements thereof. The peripheral edge of the membrane is tightly sealed between the two cups 13, 14 and may comprise a bead favorable to achieving sealing.

The second chamber 12 is provided with a suction orifice 20, provided in the cup 14, which is lower, according to the representation of Fig. 1 . The auxiliary liquid may come from a reservoir (not shown) connected by a pipe to a fitting 21 fitted to the orifice 20. A suction valve 22 is further provided at this orifice 20, which allows the suction auxiliary liquid in the chamber 12, and prevents its discharge.

The cup 14 further comprises a discharge orifice 23, communicating with the chamber 12, equipped with a discharge valve 24 and a connector 25 on which is connected a flexible pipe 26. The discharge connection 24 opens when the rise in pressure in the chamber 12 to allow the passage of the liquid to the pipe 26. This discharge valve 24 closes during the suction of the auxiliary liquid.

The flexible pipe 26 is connected, by a connection 27, to a sleeve 28 defining an injection chamber S downstream of the outlet 3. The sleeve 28, T, has a lateral orifice on which the fitting is mounted. 27, an axial port 29 on the outlet side 3, and another axial port 30 on the opposite side. The orifice 29 is provided with a connection 31 at the outlet 3 of the dispenser.

The sleeve 28 and the connection 27 and the auxiliary liquid inlet are located downstream of the outlet 3 of the metering device, and the auxiliary liquid does not enter the interior volume 9 of the metering unit. The mixing of the auxiliary liquid with the main liquid is carried out downstream of the outlet 3, and is discharged through the orifice 30, as indicated by the arrow F.

The membrane M delimits, on the opposite side to the second chamber 12, a space E (see Fig. 2 ) communicating with the first chamber 6 through the bore 18. This space E is also delimited by the bottom of the concavity of the cup 13.

A throttling member 32 is provided at the outlet of the metering body, upstream of the connection 27 and the injection of auxiliary liquid. This throttling member 32 is provided to create a sufficient pressure drop between the downstream and the interior volume 9 located upstream. The pressure difference thus created between the volume 9 and the injection chamber S is set to a value greater than the hydraulic head loss of the discharge line comprising the pipe 26 and the valves 25, 27 (pressure drop in the connection between the second chamber and the injection chamber) to allow to push back the membrane M at the end of aspiration. This pressure difference between the volume 9 and the chamber S is advantageously at least 0.2 bar. The throttling member 32 is generally constituted by a calibrated check valve which prevents the return of product to the metering body.

The throttling member 32 may be constituted by a plug with a cylindrical skirt 33 comprising at least one slot 34, in particular longitudinal, giving it a certain elasticity. The longitudinal position of the member 32 in the orifice 29 is adjustable to allow adjustment of the pressure drop. The member 32 comprises, at each of its ends, shoulders which ensure its maintenance in the orifice 29. A spring may be provided to return the member 32 to the desired throttling position.

The operation of the doser is as follows.

The aspiration phase corresponds to the upward stroke according to Fig.1 or forward stroke, the hydraulic motor 4 and the plunger 5 which creates a vacuum in the first chamber 6. This depression causes a movement of the membrane M upwards which corresponds to an increase in the volume of the chamber 12. The membrane M creates itself a depression in the chamber 12, which causes the lift of the suction valve 22 and an auxiliary liquid inlet in the chamber 12, while that the discharge valve 24 remains closed.

When the plunger 5 leaves the chamber 6 at the end of the forward stroke, the difference in pressure existing between the internal volume 9 of the metering body and the injection chamber S makes it possible to push back the membrane M and to ensure a beginning of discharge by opening the valve 24 and injection into the pipe 26 and the chamber S.

Preferably, the longitudinal position of the chamber 6 is adjustable, in particular by means of a ring B which, by rotation, makes it possible to adjust the axial position of the liner 6a, the wall of which can slide inside the body. Means such as those shown by FR 2 681 646 may be provided to allow this adjustment.

The suction valve 22, the discharge valve 24, the seal 10 of the plunger and the throttle member 32 are sized and adjusted to ensure proper operation of the dispenser.

In the repression phase, corresponding to Fig. 2 , the piston 5 descends into the chamber 6 by creating a slight overpressure in the body of the proportioner B as a result of the pressure drop in the seal 10 forming a valve. The descent of the piston 5 is not sufficient for delivery into the injection chamber S. The discharge is ensured by the fact that the pressure in the internal volume 9 is greater than the hydraulic head loss in the connection line 25, 26, 27. This gives the complete displacement of the membrane M and the maintenance of the opening of the valve 24.

The membrane M is pushed down, the suction valve 22 is closed, while the discharge valve 24 has opened for the injection of the auxiliary liquid into the chamber S. The membrane M comes to bear against the wall of the concavity of the cup 14.

The movable seal 10 of the plunger 5 serves as a safety valve to prevent excessive pressure build-up in the chambers 6 and 12.

The Fig.4 and 5 illustrate an alternative embodiment with metering body 1.1, according to which the plunger 5.1 is equipped with a fixed seal 10.1, tight up and down, and a calibrated check valve 35. Elements identical or similar to elements already described with reference to the preceding figures are designated by the same references, without their description being repeated.

The valve 35, advantageously of the ball and spring type, is installed in a chamber 36 provided at the end of the plunger 5.1 and opening at its end. The chamber 36 communicates through channels 37 with the space beyond the seal 10 .1, on the side of the volume 9 of the metering body. The valve 35 can be opened on the descent of the plunger 5.1 when the pressure in the lower part of the chamber 6 becomes greater than a limit determined by the taring of the valve. During the rise of the plunger 5.1, the valve 35 remains closed.

The operation of the variant of Fig.4 and 5 is similar to that of the doser of Fig.1-3 . However, the valve function 35 makes it possible to tare the opening pressure so that the membrane is forced back.

The interest of the variant of Fig.4 and 5 is to be able to establish an opening pressure determined by tared valve 35. A conventional embodiment by floating seal is accompanied, by cons, a singular hydraulic head loss low if it is low flow.

The Fig.1-3 correspond to a pump configuration according to which the internal volume 9 of the metering body communicates directly with the outlet 3; the pressure is substantially the same in the interior volume of the body and at the exit; the pressure drop created by the throttling member 32 ensures a sufficient pressure difference between the interior volume 9 of the metering body and the injection chamber S.

Fig.6 illustrates an alternative pump configuration in which the interior volume 9.2 of the metering body communicates directly with the inlet 2.2 of the metering unit. The pressure drop of the motor between the internal volume 9.2 of the metering body and the outlet 3.2, if it is greater than the hydraulic head loss in the connection between the second chamber 12.2 and the injection chamber S.2, may be sufficient to push back the membrane, in which case the throttling member 32 can be avoided.

The proportional doser according to the invention makes it possible, economically and effectively, to avoid any entry of auxiliary liquid into the metering body, while using a conventional metering body and hydraulic motor, by replacing the standard suction valve. by a simple kit to install.

The control of the membrane M is carried out with the main liquid, generally motive water, and a plunger 5 dosing. The construction of the whole is facilitated. The direct control with the plunger 5 makes it possible not to have a pressure equalization system which would be necessary on a hydraulic pump with hydraulic control and intermediate fluid. In case of clogging of the pipe 26 downstream of the discharge valve 24, the seal 10 of the plunger 5 plays its role of safety valve.

Claims (11)

1. A proportional dosimeter for metering an auxiliary liquid into a main liquid, comprising a dosimeter body with a main liquid inlet (2, 2.2) and an outlet (3, 3.2), a hydraulic motor (4) housed in the body, actuated by the main liquid, and connected to a plunger piston (5, 5.1) to drive same in a reciprocating rectilinear movement, the plunger piston moving in a first chamber (6) that is open at a first end (7) away from the hydraulic motor and opens at a second end (8) into the interior volume (9, 9.2) of the dosimeter body containing main liquid, the plunger piston performing an intake phase during an outward stroke in which it moves away from the first end (7) of the chamber, it being possible for the plunger piston to leave the first chamber at the end of the outward stroke, a valve being provided to allow the liquid to pass to the interior volume of the body, during the return stroke, once a certain pressure in the first chamber is exceeded,
   characterized in that it comprises a variable-volume second chamber (12) bounded by a membrane (M) subjected to the pressure obtaining in the first chamber (6), the second chamber (12) comprising an intake orifice (20) for the auxiliary liquid and a delivery orifice (23) for the auxiliary liquid, this delivery orifice being connected by a duct (26) to an injection chamber (S) situated downstream of the outlet of the dosimeter body so that the auxiliary liquid can mix with the emerging main liquid.
2. The dosimeter as claimed in claim 1, characterized in that it is arranged in such a way that the pressure in the interior volume (9, 9.2) of the dosimeter body is greater than the sum of the pressure in the injection chamber (S) and of the loss of hydraulic head in the connection between the second chamber (12) and the injection chamber (S).
3. The dosimeter as claimed in claim 1 or 2, characterized in that a restriction member (32) is provided downstream of the outlet (3) of the dosimeter and upstream of the injection chamber (S) in order to create a head loss.
4. The dosimeter as claimed in any one of the preceding claims, characterized in that the second chamber (12) is equipped with an intake valve (20) and with a delivery valve (23).
5. The dosimeter as claimed in any of the preceding claims, characterized in that the membrane (M), on the opposite side to the second chamber (12), bounds a space (E) communicating with the first end (7) of the first chamber (6).
6. The dosimeter as claimed in any one of the preceding claims, characterized in that the second chamber (12) is situated in a volume bounded by opposing concavities of a first cup (13) and of a second cup (14) which are assembled, the periphery of the membrane (M) being clamped in a fluidtight manner between the two assembled cups, the first cup (13) being fixed to the dosimeter body (1) around the first end (7) of the first chamber, while the second cup is equipped with the intake orifice (20) and with the delivery orifice (23).
7. The dosimeter as claimed in claim 6, characterized in that the central part of the membrane (M) is secured to a rigid disk (16) itself secured to an axial rod (17) facing away from the second chamber (12) and able to slide in a guide bore (18) of the dosimeter body, while leaving a passage for the liquid.
8. The dosimeter as claimed in any one of the preceding claims, characterized in that the axial position of a sleeve (6a) delimiting the cylindrical first chamber (6) in which the plunger piston moves can be adjusted using a rotary ring.
9. The dosimeter as claimed in any one of the preceding claims, characterized in that the restriction member (32) situated downstream of the outlet (3) of the dosimeter body consists of a plug fitted with a cylindrical skirt (33) with at least one slot (34), installed on an inlet orifice of a union (28) connected to the outlet of the dosimeter body.
10. The dosimeter as claimed in any one of the preceding claims, characterized in that the valve provided to allow the liquid to pass to the interior volume (9) of the body, during the return stroke, once the pressure in the first chamber (6) has exceeded a certain pressure, is a preloaded valve (35) installed in a chamber (36) provided at the end of the plunger (5.1).
11. The dosimeter as claimed in one of claims 1 to 3, characterized in that the interior volume (9.2) of the dosimeter body communicates directly with the inlet (2.2) of the dosimeter so that the head loss of the motor between the interior volume (9.2) of the dosimeter body and the outlet (3.2) contributes to pushing the membrane back.

Images