Volume-metering pump device

Abstract

The volume-metering pump device comprises a pump member associated with a manifold member comprising a body containing a manifold chamber having ports providing connections with the pump member, with an admission duct connected to a feed vessel, and with a discharge duct, and in which a manifold control element is mounted to move along a longitudinal axis of the manifold chamber, the ports providing connections with the admission duct and with the discharge duct being disposed facing each other and being coaxial about the longitudinal axis of the manifold chamber on either side of the port providing a connection with the pump member, and being adjacent to seats facing towards the inside of the manifold chamber with which valve-member forming portions made at the ends of the manifold control element co-operate to enable one or the other of the ports to be closed.

Description

[0001] The present invention relates to a volume-metering pump device.

BACKGROUND OF THE INVENTION

[0002] Volume-metering pump devices are known that comprise a pump member associated with a manifold member comprising a body containing a manifold chamber having ports providing connections with the pump member, with an admission duct connected to a feed vessel, and with a discharge duct, and in which a manifold control element is mounted to move along a longitudinal direction of the manifold chamber and is actuated by a control member so as to put the pump member into communication in alternation with the admission duct or with the discharge duct.

[0003] In existing-devices, and in particular the device described in British patent document GB-A-968 452, the manifold control element is mounted to slide with reciprocating motion in the manifold chamber and has toroidal rubber valve members mounted on the manifold member outside the manifold chamber. When the pump device is in operation, the pump chamber is in communication with the admission duct or with the discharge duct as a function of the position of the manifold control element. During the displacements of the manifold control element, some of the fluid being pumped accumulates between the toroidal valve members and the manifold control element. This fluid is difficult to extract during washing so that in practice it is not possible to perform pumping under sterile conditions when using existing devices.

OBJECT OF THE INVENTION

[0004] An object of the present invention is to propose a volume-metering pump device that can operate easily under sterile conditions.

SUMMARY OF THE INVENTION

[0005] In order to achieve this object, the invention provides a volume-metering pump device comprising a pump member associated with a manifold member comprising a body containing a manifold chamber having ports providing connections with the pump member, with an admission duct connected to a feed vessel, and with a discharge duct, a manifold control element being mounted to move along a longitudinal axis of the manifold chamber and being actuated by a control member, the port providing a connection with the admission duct and the port providing a connection with the discharge duct being disposed facing each other and coaxially about the longitudinal axis of the manifold chamber on opposite sides of the port providing a connection with the pump member and being adjacent to respective seats facing towards the inside of the manifold chamber, and the manifold control element has ends shaped to form valve members adapted to come to bear in leaktight manner against one or the other of the seats under drive from the control member of the manifold control element.

[0006] Thus, even though it ensures that one or other of the ports is closed in leaktight manner during operation of the pump device, the manifold control element can easily be cleaned by moving the valve member away from its seat and causing the cleaning fluid to flow around the valve member.

[0007] In an advantageous version of the invention, the pump member has a cylindrical pump chamber in which there is mounted a piston without gaskets that is connected to an actuator member for moving the piston along an axial direction of the pump chamber, and at an end remote from the port providing a connection between the manifold chamber and the pump chamber, the pump chamber is connected to a feed vessel, the piston being mounted in the pump chamber with clearance that is small enough to ensure that a fluid contained in the feed vessel does not flow around the piston.

[0008] Thus, while pumping a fluid, a thin film of fluid forms between the piston and the pump chamber, such that sealing is provided between the piston and the pump chamber, with this film of fluid being easily eliminated during cleaning.

[0009] According to other aspects of the invention that are advantageous, the pump member includes an auxiliary chamber lying on the same axis as the pump chamber and opening out into the feed vessel, and the stroke of the piston actuator member is preferably sufficiently long to enable the piston to be brought fully into the auxiliary chamber, the auxiliary chamber having a diameter that is large enough to allow fluid to flow around the piston. The auxiliary chamber then performs three functions, i.e. for a position of the piston inside the pump chamber, it serves to seal the piston, and when the piston is brought into the auxiliary chamber during washing, the piston is thoroughly subjected to the effects of the cleaning fluid so that the auxiliary chamber acts as a piston-washing chamber. In addition, with the piston in this position, the pump chamber is disengaged and it is therefore itself cleaned thoroughly by the washing fluid. Finally, during initial filling of the installation with the fluid product for packaging, the piston is brought into the auxiliary chamber so that the fluid product flows around the piston in order to fill the pump chamber and the manifold chamber, and bubbles of air can rise into the feed vessel so that the auxiliary chamber also acts as a gravity feed chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other characteristics and advantages of the invention appear on reading the following description of a preferred and non-limiting embodiment of the invention described with reference to the accompanying figures, in which:

[0011] FIG. 1 is an axial section view on a vertical plane through a device of the invention and the feed vessel associated therewith, for an admission position of the manifold control element; and

[0012] FIG. 2 is a section view analogous to that of FIG. 1, for a washing position of the pump device.

DETAILED DESCRIPTION OF THE INVENTION

[0013] With reference to FIG. 1, the pump device comprises a pump member 1 connected to a feed vessel 2 and associated with a manifold member 3. The pump member comprises a pump body 4 having a pump chamber 5 in which a piston 6 without gaskets or piston rings is mounted to slide with very little clearance, for example clearance of a few tenths of a millimeter. The piston 6 is actuated by a rod 7 connected to an actuator member 8.

[0014] Between the pump chamber 5 and the feed vessel 2, the pump member 1 has an auxiliary chamber 9 on the same axis as the pump chamber 5, and of transverse dimension D considerably greater than a transverse dimension d of the pump chamber 5, and opening out into the feed vessel 2.

[0015] The manifold member 3 comprises a body 10 containing an elongate cylindrical manifold chamber 11 having a longitudinal axis 36. The manifold chamber 11 includes a port 12 leading to the pump member 1. The port 12 opens out into the side of the manifold chamber 11. At each of its ends, the manifold chamber 11 has respective ports 13 and 14 coaxial about the longitudinal axis 36 and facing each other on either side of the port 12. Adjacent to the ports 13 and 14, the manifold chamber includes zones configured to provide respective seats 33 and 34 that are coaxial about the longitudinal axis 36 and that face towards the inside of the manifold chamber. The seats 33 and 34 are disposed so that each of them receives a respective end 15 or 16 shaped to form a valve member and belonging to a cylindrical manifold control element 17 mounted to slide in a longitudinal direction in the manifold chamber. The valve members 15 and 16 are thus located between the seats 33, 34.

[0016] The manifold control element has a control rod 18 extending in a bore 27 and connected to a control member 19. The control member 19 comprises an actuator member 35 and a member 20 for coupling through a wall without piercing it. For example, the coupling member comprises in conventional manner a magnet 21 carried by a rod 22 associated with the actuator member 35 and mounted to move in a glove finger 23 of non-magnetic material, together with a magnetic ring 24 surrounding the glove finger 23 and connected to the control rod 18 by a U-shaped bracket 25. The manifold control element 17 is held coaxially in the manifold chamber 11 by guide fins 26 that slide in the bore 27 on the same axis as the manifold chamber 11, and guide fins 28 sliding in a bore 29 that likewise lies on the same axis as the manifold chamber 11. The port 14 is connected to an admission duct 30 via the bore 27 and an admission chamber 31 surrounding the coupling member 20. At its top end, the admission duct 30 opens out into the bottom end of the auxiliary chamber 9.

[0017] The port 13 is connected to a discharge duct 32 by the bore 29. The discharge duct 32 is connected to a metering spout that is not shown.

[0018] The actuator member 8 presents a stroke that is sufficient not only to drive the piston 6 back and forth in the pump chamber 5, but also to pull the piston 6 out of the pump chamber 5 into the auxiliary chamber 9, as shown in FIG. 2.

[0019] The valve member 15 of the manifold control element 17 is shaped to close the port 13 in leaktight manner when the valve member 15 is pressed against the seat 33 adjacent to the port 13. Similarly, the valve member 16 is shaped to close the port 14 in leaktight manner when the valve member 16 is pressed against the seat 34 adjacent to said port. The distance between the valve members 15 and 16 is shorter than the distance between the seats 33 and 34 so that when one of the ports is closed, the other is wide open. Furthermore, the transverse size of the manifold control element 17 is considerably smaller than the transverse size of the manifold chamber 11 so that the product for dispensing flows easily around the manifold control element 17 when either one of the ports 13 or 14 is open.

[0020] When the installation including the pump device of the invention is initially started up, the valve member 16 is caused to press against its seat 34 so that the port 13 is wide open. The piston 6 is raised into the auxiliary chamber 9 as shown in FIG. 2. In this position, the product for packaging flows under gravity into the auxiliary chamber 9 and flows around the piston 6, thereby firstly filling the admission duct 30 and secondly filling the pump chamber 5 and filling the manifold chamber 11 and the discharge duct 32. The auxiliary chamber 9 thus acts as a gravity feed chamber.

[0021] The piston 6 is then lowered to the end of its stroke in the pump chamber 5 and is then driven with reciprocating motion over a stroke that keeps the piston 6 in the pump chamber 5. On each upward stroke of the piston, the valve member 15 is brought to bear against the seat 33 adjacent to the connection opening 13 so as to close it. The connection opening 14 is then wide open and the product for packaging is sucked into the pump chamber 5, passing via the auxiliary chamber 9 and the admission duct 30, the admission chamber 31, and the manifold chamber 11. On each downward stroke of the piston 6, the manifold control element 17 is moved to close the port 14 and to open the port 13 so that a volume of product corresponding to the stroke of the piston 6 is propelled by the piston 6 into the discharge duct 32. The auxiliary chamber 9 then acts as a sealing chamber relative to the piston.

[0022] When the feed vessel 2 is empty, a washing liquid is introduced into the feed vessel 2 and the pump device is put into the position shown in FIG. 2, i.e. the piston 6 is raised so as to extend within the sealing chamber 9, and the manifold control element 17 is put into an intermediate position in which both ports 13 and 14 are open. The washing liquid flows in the discharge duct 32, passing simultaneously through the admission duct 30 and the pump chamber 5. The auxiliary chamber 9 then performs a washing function. In addition, this system enables all of the air to be purged while washing the spout, by allowing the air to rise into the vessel.

[0023] Naturally, the invention is not limited to the embodiment described above and variants thereof will appear to the person skilled in the art without going beyond the ambit of the invention as defined by the claims.

[0024] In particular, although the device described combines a manifold member without any gasket and a pump member without any gasket, the manifold member without gaskets could be used together with a pump member of traditional structure, the admission duct then being connected directly to the feed vessel.

[0025] Although in the embodiment shown an auxiliary chamber is interposed between the pump chamber and the feed vessel, the invention can be implemented with a pump chamber that opens out directly into the feed vessel, which then acts as an auxiliary chamber both for gravity feed purposes and for pumping and washing.

[0026] Conversely, the auxiliary chamber could be separate from the feed vessel and be connected thereto by a duct.

Claims

1. A volume-metering pump device comprising a pump member associated with a manifold member comprising a body containing a manifold chamber having ports providing connections with the pump member, with an admission duct connected to a feed vessel, and with a discharge duct, a manifold control element being mounted to move along a longitudinal axis of the manifold chamber and being actuated by a control member, the port providing a connection with the admission duct and the port providing a connection with the discharge duct being disposed facing each other and coaxially about the longitudinal axis of the manifold chamber on opposite sides of the port providing a connection with the pump member and being adjacent to respective seats, wherein the seats face towards the inside of the manifold chamber, and the manifold control element has ends shaped to form valve members adapted to come to bear in leaktight manner against one or the other of the seats under drive from the control member of the manifold control element.

2. A pump device according to claim 1, wherein the control member is a magnetic member adapted to control displacement of the manifold control element through a wall, without piercing the wall.

3. A pump device according to claim 1, wherein the pump member has a cylindrical pump chamber in which there is mounted a piston without gaskets that is connected to an actuator member for moving the piston along an axial direction of the pump chamber, and wherein, at an end remote from the port providing a connection between the manifold chamber and the pump chamber, the pump chamber is connected to a feed vessel, the piston being mounted in the pump chamber with clearance that is small enough to ensure that a fluid contained in the feed vessel does not flow around the piston.

4. A pump device according to claim 3, wherein, between the pump chamber and the feed vessel, the pump member includes an auxiliary chamber of transverse dimension greater than a transverse dimension of the pump chamber.

5. A pump device according to claim 4, wherein the auxiliary chamber is on the same axis as the pump chamber and opens out into the feed vessel.

6. A pump device according to claim 5, wherein the actuator member presents a stroke that is long enough to be able to bring the piston into a position in which the piston is withdrawn into the auxiliary chamber sufficiently to allow fluid to flow around the piston into the pump chamber.

7. A pump device according to claim 6, wherein the admission duct opens out into the auxiliary chamber.