EP2220418A1

EP2220418A1 - Non-drip coupling device for transferring a fluid

Info

Publication number: EP2220418A1
Application number: EP08845772A
Authority: EP
Inventors: René Bøgelund NYBERG; Graziano Cancian
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 2007-10-30
Filing date: 2008-10-29
Publication date: 2010-08-25
Also published as: WO2009056139A1

Abstract

Coupling device to transferring a flow of fluids or substances, which device comprises a first coupling element (1) and a second coupling element (11). The first coupling element (1) comprises fluid channels with displacing elements (4) and first sealing elements (7) positioned by spring force from the biasing members (6) to seal the fluid openings in the displacing elements(4) when the coupling device is disconnected by the two coupling elements separated. The second coupling element (11) comprises fluid channels with valve bodies (15) positioned by spring force from second biasing members (16) to close the fluid openings and second sealing elements (17) to seal the second bores(13) in the second coupling element (11) when the coupling device is disconnected. When the two coupling elements are pushed together and guided by guiding elements (30) the fluidic flows are connected between inlets (14) and outlets (9). The sealing elements (7, 17) ensure tightness.

Description

Non-drip coupling device for transferring a fluid

Technical field

The new invention concerns a non-drip fluid coupling device intended for transferring a flow of at least one substance e. g. a fluid.

Background and purpose of the invention

Many reasons exist for connecting flow systems such as measuring the concentration of substances in a fluid like glucose in blood or nutrition's in waste water where samples are taken from the fluid and mixed with reagents to give a detectable reaction as representative of the concentration. Another example concerns fluids working as energy resources for an operating system such as a machine or fuel cells. In any case there would be a need to exchange fluids when the reservoirs become exhausted. The fluids may be anything like liquids, gases or aerosols.

When for example the fluids are aggressive (e. g. toxic or corrosive) it is critical to ensure that no dripping occurs during connection and disconnection of e.g. fluid reservoirs to an operation system or fuel cells.

Prior art

A number of documents concern such fluid couplings. US 5,293,902 describes a quick disconnect coupling for connection to a fluid fitting, having a Schroeder valve, said coupling comprising:

• a body formed with an axial bore and a passageway in communication with said bore, said bore being formed with an open end to receive said fluid fitting there-within and an annular shoulder ; • an annular seal within said bore mounted in a groove formed in said body for sealingly engaging an outside diameter of said fluid fitting upon receipt of said fluid fitting;

• a locking means for removably attaching said body to said fluid fitting and for maintaining contact of said annular seal with a ridge portion of said fluid fitting said locking means being reciprocally attached to said body;

• a single valve pin reciprocally mounted within said axial bore for movement between a closed position wherein said valve pin engages said annular shoulder of said bore to create a seal and prevent communication between said open end and said passageway, and an open position wherein communication is permitted, said valve pin being moveable in response to engagement with said fluid fitting, said valve pin including an extension for contacting and opening the Schroeder valve and a base portion for contacting said fluid fitting and for limiting penetration of said extension into said fluid fitting; and

• a biasing means connected with said body and said valve pin for adjustably biasing said valve pin into said closed position.

This system has the disadvantage that it is not a non-dripping coupling since the axial bore (16) would contain fluid when disconnected and a sealing of the fluid fitting (54) does not exist.

WO 2006/043883 describes a coupling device intended for transferring a flow of a substance, which device comprises a first coupling element and a second coupling element. The first coupling element comprises a fluid channel and a first sealing element displaceable from a sealing position under the effect of spring force, and also a rigid first displacing element. The second coupling element comprises a fluid channel and a second sealing element displaceable from a sealing position under the effect of spring force and also a rigid second displacing element. Said sealing elements on each coupling element are arranged to sealingly close the inlet (outlet) of the fluid channel when the two coupling elements are separated. The first displacing element is arranged to displace the second sealing element out of the sealing position when the said coupling elements are connected and the second displacing element is arranged to displace the first sealing element on the first coupling element out of the sealing position when the said coupling occurs. The two coupling elements have smooth coupling surfaces, which are separated from the flow through the fluid channels after connecting the coupling elements.

This coupling is not suitable for multi-fluid couplings where a plural of fluid connections are built into the same coupling device. The reason is that the first coupling element (1) would 'extend' from a common base and would therefore be vulnerable to being bent out of true making the connection difficult and possible even leaking. Cracks might also easily occur.

The couplings in both documents, however, have several pieces to be fitted into bores complicating the manufacturing process and increasing the risk of mal-functions of the parts in the bores which might lead to a leaky connection during operation. Further they have special shapes adapted to fit together which complicates the manufacturing processes as well.

Especially for fuel cells regulations from the authorities dictate non-dripping fluid connections and since a plural of fluid connections are necessary it would be convenient to have a stable and robust multi-fluid coupling device according the new invention.

Object of the invention

It is an object of this invention to design a stable non-dripping fluid coupling system without the drawbacks of the prior art and which is able to handle more than one fluid coupling. This object is achieved with a fluid coupler device as described in claim 1.

Such a fluid coupler device comprises a first coupling element connected to a second coupling element. The first coupling element with at least one outlet connection has a displacement element in a first bore and when the first coupling element is connected to the second coupling element the displacement element pushes a valve body away and opens a fluid access from at least one fluid opening connection in the second coupling element. By pushing the valve body away, energy is stored in a biasing member e.g. a spring. When the two coupling elements are disconnected, the biasing member releases the energy to push the valve body back to close the fluid opening and fluid access.

The solution is non-dripping due to the closing operation where any left fluid or substance will pass through the fluid coupling device in a sealed fluid channel during the whole closing operation.

The displacement element is advantageously made from an acid-resistant steel in order to withstand aggressive fluids and make the construction of the component rigid.

The invention is especially suitable for systems where more than one fluid connection is done simultaneously and is especially meant for connecting a fluid reservoir of aggressive up heated methanol, sulphuric acid or nitric acid to e.g. fuel cells where it is a legal demand in many countries to use non- dripping devices for filling processes.

Such a robust design makes the manufacturing process easier and minimizes risk of mal-functions during operation. Further it is a desire to create a system where many parts are commercially available standard components minimizing cost of production. Figures

Fig. 1 shows the first and the second coupling elements prior to connection.

Fig. 2 shows at an angle the first and the second coupling elements prior to connection.

Fig. 3 shows the displacement element in a first bore.

Fig. 4 shows a close up of one of the second bores with valve body and second biasing member.

Fig. 5 shows the first coupling element coupled to the second coupling element.

Fig. 6 shows a close up of a second bore where a displacement element has pushed the valve body away from the fluid access.

Fig. 7 shows the preferred embodiment of the valve body.

Fig. 8 shows the preferred embodiment of the third sealing element.

Fig. 9 shows the preferred embodiment of the second sealing element.

Fig. 10 shows the preferred embodiment of the first sealing element.

Fig. 11 shows an alternative second embodiment of the two coupling elements. Detailed description of the invention

Fig 1 shows a first preferred embodiment of the fluid coupler prior to operation, where the first body (2) of the first coupling element (1) is 'opened' to show the internal structures. The first body (2) in the present embodiment has non-limiting six first bores (3) but any number of first bores (3) would apply to the invention like just a single one. The first bores (3) may be any kind of cavities in a body having two openings towards the outside and where the body and the cavity could be manufactured in any known manner. Preferably one of the openings to the outside of the first bores (3) is equipped with a thread (9).

Across the first bores (3) a plate element (20) having first holes (21) connected to the first body (2) in such a manner that the second section outside to the first bores (3) of the displacement elements (4) extends through the first holes (21).

At least one first biasing member (6) e. g. a concentrically spring is positioned between the first body (2) and the plate element (20) where the first biasing member (6) in the preferred and illustrated embodiment is positioned around the displacement element (4) being between the first base body (2) and the plate element (20).

A first sealing element (7) is slide ably positioned around the end tip section of the displacement element (4), the end tip section being the part extending through the first holes (21) and thus being at the side of the plate element (20) opposite to the first biasing member (6).

At least one male guiding element (30) is securely attached to or in the first body (2) and extends in a preferred embodiment through second holes (22) of the plate element (20). Each male guiding element (30) is equipped with an extension part (31) preferably a lock ring mounted in a fixed position at the guiding element (30).

The second coupling element (11) has a second body (12) comprising a number of second bores (13) equivalent to the number of displacement elements (4) and the second bores (13) are adapted to fit and receive a part of the external section of the displacement elements (4).

Fig. 2 shows the same as fig. 1 but from another angle and where the fluid accesses (14) are easier to see. The illustrated embodiment is equipped with threads (19) just like in the first bores (3) equipped with threads (9). Neither the threads (9) or (19) are essential to the invention why any other imaginable manner of connecting e.g. reservoirs or other fluid conduits to the fluid accesses (14) and first bores (3) would also apply.

The second body (12) and the second bores (13) may be manufactured in the same way as the first body (2) and the first bores (3). Each second bore (13) has a fluid access (14) and a valve body (15) filling enough of the second bore (13) to close the fluid access (14) prior to operation of the system. A second biasing member (16) is positioned in the second bore (13) where the second biasing member (16) pushes the valve body (15) to the position where it closes the fluid access (14). The second sealing element (17) having a through hole is securely mounted at the opening of the second bore (13). The third sealing element (18) is positioned in the valve body (15).

The second body (12) comprises at least one female guiding mean (33) equipped with a recess (34) where the internal diameter of the female guiding mean (33) becomes smaller than the opening section (35).

Fig 3 shows a displacement element (4) positioned in a first bore (3), where the displacement element (4) has an internal flow conduit (44) connecting a first opening (41) to the outside to a second opening (40) to the outside. The displacement element (4) is positioned in the first bore (3) in such a manner that a first section comprising the first opening (41) is positioned within the first bore (3) and a second section comprising the second opening (40) is outside to the first bore (3).

As it is shown the displacement element (4) has an expansion (42) of the external diameter around the first opening (41) formed to fit to a similar shape as a shoulder (43) inside the first bore (3). A fourth sealing element (8) with a through hole is positioned in the first bore (3) in connection with the displacement element (4) in such a way that when the fourth sealing element (8) is fixed by e.g. a screwed connection in the first bore (3), it presses the expansion (42) against the shoulder (43) thereby firmly securing positioning of the displacement element (4) and tightening the first bore (3). The through hole of the fourth sealing element (8) ensures fluidic communication between the internal flow conduit (44) of the displacement element (4) and the threaded opening (9) of the first bore (3) across the first opening (41) and the through hole of the fourth sealing element (8). Preferably the fourth sealing element (8) becomes fixed by inserting a screwed connector to the thread (9) of the first bore (3).

The end tip (45) can optionally be made of some substantially soft sealing material.

According fig 1 the first sealing element (7) is positioned at the displacement element (4) so that the second opening (40) is sealed from the outside when the device is in the disconnected position.

Fig. 4 shows a close up of a second bore (13) where the valve body (15) is shown to have a section (51) with a reduced external diameter where the second biasing member (16) e. g. a spring is attached to the valve body (15) surrounding the section (51) in a substantially eccentric manner. The internal cavity of the valve body (15) has an enlarged section (53) into which the third sealing element (18) fits. The second sealing element (17) at the opening of the second bore (13) is preferably fixed by some adhering material and/or any retaining ring or locking mechanism (50).

Fig. 5 shows the fluid coupler device when the first coupling element (1) is connected to the second coupling element (11) and flow is established. The male guiding elements (30) of the first coupling element (1) are introduced into the female guiding means (33) ensuring the correct alignment of the two coupling elements (1 , 11). The expansion part (31) of the male guiding element (30) has a bigger diameter than the internal diameter of the recess (34) of the female guiding mean (33) and therefore defines the stop position where the first coupling element (1) is fully connected to the second coupling element (11) .

The plate element (20) is pushed closer to the first body (2), pressing the first biasing member (6) together and thereby storing energy in it. Then it is ready for release when the two coupling elements (1 , 11) will be disconnected. The section of the displacement element (4) outside to the first bore (3) is extended further through the first hole (21) and into the second bore (13) where it has traversed the through hole of the second sealing element (17). Then the end tip (45) has entered into the third sealing element (18) pushing it and the valve body (15) away from the fluid access (14) and thereby pressing the second biasing member (16) together and storing energy in it.

The first sealing element (7) being slide ably positioned on the displacement element (4) has moved down the outer diameter of the displacement element (4) as it has passed out of the first hole(21) and the first sealing element (7) is now in contact with the second sealing element (17) and creates sealing. Preferable the first sealing element (7) is securely fixed to the plate element (20). The operation stop position defined by the expansion part (31) of the male guiding element (30) and the recess (34) of the female guiding mean (33) corresponds to the position where the second opening (40) of the displacement mean (4) aligns with the fluid access (14) of the second bore (13) and ensures open fluidic connection to the first bore (3).

Fig. 6 shows a close up of one of the second bores (13) during operation where the displacement element (4) is positioned into the third sealing element (18) and pushed it and the valve body (15) away from the fluid access (14) (not shown). The plate (20) is pushed towards the first body (2) thereby squeezing the first biasing member (6) to store releasing energy into it.

When the first coupling element (1) and the second coupling element (11) are disconnected the displacement elements (4) leaves the second bores (13), so that the second biasing members (16) may release the stored energy to push the valve bodies (15) back to the position where they close the fluid accesses (14). In the same manner, the first biasing members (6) push the plate (20) 'away¹ from the first body (2) to take the displacement elements (4) back to their initial 'prior to operation¹ position as shown in fig 1. Further the plate (20) ensures that the first sealing elements (7) are pushed back to their initial position at the end tip of the rigid displacement elements (4) closing and sealing the second openings (40) again.

During the complete connecting and disconnecting operations the second opening (40) is sealed from the outside by the first sealing member (7) and the second sealing member (17). The first sealing member (7) ensures that the second opening (40) is sealed when the first coupling element (1) and the second coupling element (11) are disconnected. And as well the valve body (15) and second sealing element (17) seal the fluid accesses (14) when the first coupling element (1) and the second coupling element (11) are disconnected. Due to those described sealing functions during complete connecting and disconnecting operations the system or unit is ensured to be non-dripping.

Fig. 7 shows the valve body (15) having the internal cavity (52) of a first internal diameter and the section (53) of a second internal diameter larger bigger than the first. The valve body (15) has a section (51) of a reduced external diameter.

Figs. 8-10 show the sealing elements (7, 17, 18) of the system, where the external shape and dimensions of the third sealing element (18) fits into the bigger section (53) of the valve body (15). Optionally the third sealing element (18) may have a through hole (61). The second sealing element (17) has a through hole and in the preferred embodiment at least one reduced external diameter where adhering material, or more preferred a retaining ring (Fig. 4 pos. 50) may be positioned when mounted and fixed at the openings of the second bores (13). The first sealing element (7) has advantageously an indentation (60) for fixing it to the plate (20) in the first holes (21). The sealing elements (7, 17, 18) could advantageously be commercially available glands, gaskets or washers.

Fig. 11 shows a slightly different embodiment, where a substantially smaller valve body (15) is introduced, only having the enlarged section (53) of the cavity (52) for receiving the third sealing element (18). Further, no section (51) of reduced diameter is present and the second biasing member (16) is pushing onto the top of the valve body (15). However, the hollow valve body (15) of e.g. Figs. 1 and 7 is preferred since it together with the through hole (61) of the third sealing element (18) and the bigger volume in the second bore (13) helps to avoid an under-pressure between the rigid displacement element (4) and the third sealing element (18) when the two coupling elements (1) and (11) are disconnected. Furthermore the guiding elements (30) are equipped with a slideable gasket or washer (32) in the same way as the displacement elements (4) are equipped with the slideable first sealing elements (7).

Comment: It shall be noticed that the figures 1 - 11 only show a preferred embodiment of the invention. Alternative solutions are possible such as having the male guiding elements (30) attached to the second body (12) and the first body (2) equipped with the female guiding means (33). Furthermore the first coupling element (1) could be connected to e.g. fluid reservoirs and the second coupling element (2) to the system using the fluids e. g. for fuel cells etc.

Claims

Claim 1 A fluid coupling device (Fig. 1) comprising a first coupling element (1) with a first biasing member (6), and a second coupling element (11) with a second biasing member (16) placed in a bore (13) of the second coupling element and acting on a valve body (15), the first coupling element comprising a displacement element (4) placed in a bore (3) wherein the displacement element comprises a fluid channel (44) having a fluid opening (40) characterized in that the displacement element (4) extends through a hole (21) of a moveable plate element (20), the moveable element biased by the first biasing member (6) and further comprises a sealing element (7) sealing the fluid opening (40)

Claim 2

A fluid coupling device as in claim 1 wherein the displacement element (4) is hollow comprising a fluid conduit (44) with an axial first opening (41) to the outlet and a radial second opening (40) to the inlet.

Claim 3

A fluid coupler device as in claim 1 wherein the first sealing members (7) are slide able positioned at said displacement elements (4).

Claim 4

A fluid coupler device as in claim 1 wherein the second bores (13) are equipped with second sealing elements (17) secured at the entrances to the second bores (13).

Claim 5

A fluid coupler device as in claim 1 wherein the first biasing elements (6) pushes the moveable plate (20) towards the second coupling element (11) Claim 6

A fluid coupler device as in claim 1 wherein said first body (2) is equipped with male guiding elements (30) adapted to fit into female guiding means (33) in the second body (12).

Claim 7

A fluid coupler device as in claim 6 wherein said female guiding means (33) are equipped with recesses (34) where the internal diameter of the female guiding means (33) changes.

Claim 8

A fluid coupler device as in claim 7 wherein each of said male guiding elements (30) has an extension e.g. a locking ring (31) at a position corresponding to the stop position where the first opening (41) of a displacement element (4) has fluidic communication with a fluid access (14) of a second bore (13).

Claim 9 A fluid coupler device as in any of the preceding claims said valve body (15) is hollow and having a first section of cavity (52) with a first diameter.

Claim 10

A valve body (15) as in claim 9 comprises a second section of cavity (53) with a larger diameter than said first section of cavity (52) and being adapted to contain a third sealing element (18).

Claim 11

A fluid coupler device as in claim 1 wherein said first biasing members (6) and said second biasing members (16) are springs. Claim 12

A fluid coupler device as in claim 11 in an alternative second embodiment as shown in fig 11.

Claim 13,

A fluid coupler device as in claims 1 and 12 wherein the displacement element (4) is made from acid-resistant steel.

Claim 14 A fluid coupler device as in claim 13 wherein the inlet fluid connections (14) and the outlet fluid connections (9) are threads.