Background Double poppet valve couplings are well known in the prior art, and are disclosed in for instance GB 2463966 A, US 5810047 A and WO 2010/040334 Al .

A common disadvantage of the prior art connectors is the leakage of an amount of fluid during connection/disconnection of the connector. This may in many instances be unacceptable, e.g. when the connectors are used for transfer of toxic or flammable fluids.

The present invention provides a double poppet valve coupling which alleviates or avoids at least some of the disadvantages of the prior art couplings.

Summary of the invention

The present invention is defined by the attached claims, and in the following: In a first aspect, the present invention provides a double poppet valve coupling comprising a first coupling half and a second coupling half; wherein the first coupling half comprises a first housing comprising a first poppet element, a first poppet seat, a sleeve assembly and a connecting end having a connecting recess; and the second coupling half comprises a second housing, a second poppet element, a second poppet seat and a stab connecting part for coupling with the connecting recess; the first poppet element and the second poppet element are biased towards the first poppet seat and the second poppet seat, respectively, and arranged to interact and move off the respective first and second poppet seats during connection of the double poppet valve coupling, such that a flow path extending through the coupling is obtained; and the sleeve assembly comprises a flanged cylinder arranged within the first housing, the flanged cylinder comprises an annular surface for interaction with the stab connecting part and is displaceable between a first position, wherein the annular surface is proximate an opening of the connecting recess, and a second position, wherein the annular surface is distal the opening of the connecting recess.

The flanged cylinder may be a hollow cylinder having a central passage. The annular surface may be arranged at the circumference of the central passage of the flanged cylinder. The annular surface may face in the same direction as the connecting recess, i.e. in a direction towards the stab connecting part during connection of the coupling.

In an embodiment of the double poppet valve coupling according to the first aspect, the annular surface of the flanged cylinder is arranged to interact with an annular end surface of the stab connecting part.

The stab connecting part may comprise a central passage and the annular end surface. The annular end surface of the stab connecting part may be at the circumference of the central passage and may face the annular surface of the flanged cylinder during connection of the coupling. The annular end surface of the stab connecting part may push against the annular surface of the flanged cylinder during connection of the coupling, preferably such that the flanged cylinder is moved from the first position to the second position.

In an embodiment of the double poppet valve coupling according to the first aspect, the first and second poppet elements seal against the respective first and second poppet seats, when the flanged cylinder is in the first position, and is off the respective first and second poppet seats, when the flanged cylinder is in the second position.

The flanged cylinder may be arranged such that the internal free volume of the first coupling half itself (i.e. the internal free volume of the first coupling half when the stab connecting part is not present) is at a maximum when the flanged cylinder is in the second position and at a minimum when in the first position.

The outer surface of the stab connecting part and an inner surface of the connecting recess including the annular surface of the flanged cylinder may be complementary, such that a minimum void volume (i.e. a volume enclosed between an inner surface of the connecting recess and the stab connecting part) is present between the stab connecting part and the connecting recess when the stab connecting part is arranged in the connecting recess and the flanged cylinder is in the first position. In an embodiment of the double poppet valve coupling according to the first aspect, the flanged cylinder is biased towards its first position by a spring. In an embodiment of the double poppet valve coupling according to the first aspect, the spring is arranged in an annular space partly defined by an outer surface of the flanged cylinder. The annular space is minimized when the flanged cylinder is in the second position. In other words, when the flanged cylinder is in the second position the free volume within the first coupling half is maximized.

The flanged cylinder, the spring and the annular space may form parts of an annular assembly occupying a volume which is minimized when the flanged cylinder is in the second position and maximized when the flanged cylinder is in the first position. The variable volume, i.e. the annular assembly, is arranged within the first housing. The annular assembly may surround at least a section of the flow path of the first coupling half.

In an embodiment of the double poppet valve coupling according to the first aspect, the annular space is separated from the flow path and preferably pressure equalized with the surroundings of the coupling. In other words, the annular space is preferably not in fluid communication with the flow path.

In an embodiment of the double poppet valve coupling according to the first aspect the flanged cylinder comprises the first poppet seat facing in the same direction as the annular surface.

In an embodiment of the double poppet valve coupling according to the first aspect, the first poppet element is arranged to be moved off the first poppet seat in a direction opposite the direction in which the flanged cylinder is displaced from the first position to the second position.

Short description of the drawings The present invention is described in more detail by reference to the following drawings.

Fig. 1 shows an exploded cross-sectional view of a first exemplary double poppet valve coupling according to the invention.

Figs. 2a and 2b show a side view and a cross-sectional view of the coupling in fig.

1 , before the coupling is connected. Figs. 3a and 3b show a side view and a cross-sectional view of the coupling in fig.

1, during connection. Figs. 4a and 4b show a side view and a cross-sectional view of the coupling in fig.

1 , when fully connected.

Figs. 5a and 5b show a side view and a cross-sectional view of a second exemplary double poppet valve coupling according to the invention, during connection.

Figs. 6a-6c show side views and a cross-sectional view of a third exemplary double poppet valve coupling according to the invention, during connection.

Figs. 7-10 show a fourth exemplary double poppet valve coupling according to the invention.

Detailed description of the invention The present invention provides a double poppet valve coupling made up of two coupling parts, wherein each coupling part features a respective poppet valve.

A first exemplary double poppet valve coupling is shown in figs. 1-4. The coupling comprises three main components; a first coupling part 2, a second coupling part 2’, an actuating member 17 and a connecting sleeve 5. An assembly of the first coupling part 2 and the connecting sleeve 5 may be termed a first coupling half having a connecting recess (i.e. a female coupling half) and the second coupling part 2’ may be termed a second coupling half having a stab connecting part for the connecting recess (i.e. a male coupling half).

Each of the coupling parts 2,2’ comprises a housing assembly 4,4’ and a poppet element 8,8’. The housing assembly has a sleeve connecting section, featuring a first connecting end 6,6’ and an external recess 3,3’ (i.e. a sleeve fastening element) for connecting the housing assembly to the connecting sleeve 5, a second

connecting end 7,7’ and an internal poppet seat 12,12’. Each poppet element is mounted on a support plate 32 arranged at the respective second connecting end 7,7’. The support plate 32 featuring through-holes 33. The connecting sleeve 5 has a first end section 14 and a second end section 15. The first end section 14 is arranged to accommodate the sleeve connecting section of any of the first coupling part 2 and the second coupling part 2’ and comprises bores 16 through which fastening bolts may be screwed (i.e. fastening means). The bores and bolts are for releasably connecting the first end section 14 to the accommodated sleeve connecting section by interaction with the external recess 3,3’· The sleeve connecting section may in other embodiments be releasably connected to the first end section 14 by other suitable means. Other suitable means may for instance include a clamp assembly.

Seal rings 30 are arranged at an inner surface of the first end section.

The second end section 15 is arranged to accommodate the sleeve connecting section of the other coupling, i.e. the coupling part not accommodated in the first end section. Seal rings 30 are arranged at an inner surface of the second end section.

Each housing assembly defines a flow path F 1 ,F2 extending between the first and second connecting ends 6, 6’, 7, 7’ when the respective poppet element 8,8’ is moved away from the poppet seat 12,12’.

In a first position, see figs. 1-3, the poppet element 8,8’ of each coupling part is biased towards, and in sealing contact with, the internal poppet seat 12,12’ by a spring 34,34’. Consequently, in the first position, the flow path F1,F2 is closed at the first connecting end 6,6’.

During connection of the coupling, see fig. 4, the poppet element 8,8’ of each coupling part 2,2’ is moved away from the corresponding poppet seat and into a second position. When the poppet elements are in the second position, the flow path F1+F2 is open.

In the coupling of figs. 1-4, the poppet element 8 of the first coupling part 2 accommodated in the first end section 14 comprises an actuating member 17. The actuating member is releasably connected to the poppet element 8 by screwing a threaded end section 22 of the actuating member into a threaded bore 18 in the poppet element. To facilitate the releasable connection, the actuating member features a recess for an Allen key 24 (i.e. an interface for a tool suitable for screwing the threaded section into the threaded bore). The actuating member 17 extends beyond the first connecting end 6 of the housing assembly and interacts with the poppet element 8’ of the second coupling part 2’ during connection, see figs. 3 and 4. Both coupling parts 2,2’ features a threaded bore 18,18’ for

connection to the actuating member and are fully interchangeable with each other.

A flanged cylinder 28 (i.e. an internal flange) is arranged within the connecting sleeve 5. The flanged cylinder features an annular surface 19 for interaction with the first connecting end 6’ of the second coupling part 2’ when accommodated in the second end section 15 of the connecting sleeve 5. The flanged cylinder is displaceable between a first position, wherein the annular surface 19 is proximate an opening of the second end section 15 (i.e. preceding fully connecting the coupling, see figs. 1-3) and a second position, wherein the annular surface 19 is distal the opening of the second end section 15 (i.e. when the coupling is fully connected, see fig. 4). The flanged cylinder 28 is biased towards the first position by at least one spring 26. The spring 26 is enclosed in an annular space 36 separated from the flow path F3 of the connecting sleeve, i.e. the annular space is not in fluid contact with the flow path F3. The annular space 36 is pressure equalized against the surroundings or the flow path. The flanged cylinder 28, the spring 26 and the annular space 36 may be defined as forming an annular assembly occupying a volume within the first coupling part which is minimized when the flanged cylinder is in the second position and maximized when the flanged cylinder is in the first position.

The flanged cylinder 28 minimizes the fluid volume V present inside the connecting sleeve when the coupling is disconnected (i.e. the volume defined by an inner surface of the connecting sleeve 5 and the first connecting ends 6,6’ of the coupling parts 2,2’ when the poppet elements 8,8’ are in the first position). In this manner, the possible amount of fluid leakage during disconnect of the coupling may be minimized substantially.

In the coupling of figs. 1-4, even the minimal fluid leakage that may occur during disconnect is eliminated by having a valve seat 25 arranged on the flanged cylinder 28 and a plug 29 arranged on the second end 21 of the actuating member 17. The actuating member may be considered a part of the poppet element 8 and the valve seat 25 may also be termed a poppet seat. The valve seat 25 faces in the same direction as the annular surface 19 of the flanged cylinder, and the plug 29 is able to seal against the valve seat 25.

The plug of the actuating member is arranged to seal against the valve seat when the poppet element 8 of the first coupling part 2 is in the first position, i.e. when the flow path FI is closed, figs. 1-3. When the poppet element 8 of the first coupling part 2 is in the second position (i.e. when the coupling is fully connected, fig. 4), the plug is spaced from the valve seat such that the flow path F1+F2 is open. Thus, during disconnect of the coupling, the fluid volume V is sealed off from the surroundings and any fluid leakage from the fluid volume is avoided.

To further minimize leakage (or spillage since any fluid exiting the coupling during disconnect is due to fluid remaining within a volume defined by the first connecting ends of the two coupling parts and the connecting sleeve), a surface of the plug (i.e. the surface in which the recess 24 is arranged) and the annular surface 19 of the flanged cylinder 28 provides a substantially void free interface with the first connecting end of the second coupling part 2’ when the second coupling part is accommodated in the second end section of the connecting sleeve and the poppet elements are in the first position.

When the coupling is to be assembled, the sleeve connection section of the first coupling part 2 (or alternatively the second coupling part 2’ as they are fully interchangeable) is inserted into the first end section 14 of the connecting sleeve and releasably connected to the first end section by threaded bolts 16 (i.e. by operating the fastening means). The actuating member is then inserted via the second end section of the connecting sleeve and releasably connected to the poppet element of the first coupling part by screwing it into the threaded bore. To fully connect the coupling the second coupling part 2’ is inserted into the second end section of the connecting sleeve, such that the corresponding poppet elements 8,8’ interact via the actuating member and move into the second position providing a flow path (F1+F2+F3) extending between the second connecting ends 7,7’.

A second exemplary double poppet valve coupling is shown in figs. 5a and 5b. The same reference numbers are used as in figs. 1-4. The coupling is substantially similar to the coupling in figs. 1-4. The main differentiating features are the way the actuating member 17’ is connected to the first coupling part 2 and the design of the enclosed annular space 36 in which the spring biasing the flanged cylinder is arranged. Instead of being connected via a threaded section being an integral part of the actuating member (as in figs. 1-4) the actuating member in fig. 5b is releasably connected by the threaded sections 22’ of two bolts 37 extending through the actuating member 17’. It is noted that in fig. 5b it is shown how the enclosed annular space is pressure equalized with the surroundings via a pressure release channel 35.

The function of the second exemplary double poppet valve coupling is the same as described above for the coupling in figs. 1-4.

A third exemplary double poppet valve coupling 1” is shown in figs. 6a and 6b.

The same reference numbers are used as in figs. 1-5. The coupling is slightly simplified compared to the couplings in figs. 1-5. The third exemplary coupling does not feature a releasably connected actuating member or a flanged cylinder comprising a valve seat. Instead, each of the poppet elements 8,8’ comprises an integral actuating member 17” extending beyond the first connecting end of the respective first and second coupling part (i.e. the section of the poppet element extending beyond the first connecting end). Contrary to the couplings shown in figs. 1-5 and described above, the coupling in fig. 6 is not completely leakage/spillage free during disconnect. This is due to the small volume V of fluid retained in the coupling during disconnect. Due to the simplified design, the coupling 1’’ may be a cost-efficient alternative to the other couplings 1 ,1’ when some spillage of fluid is acceptable during disconnect.

The disclosed embodiments of the inventive coupling are designed to be held fully connected by an external force. For example, by being used in tank systems, such as disclosed in WO 2016/075186 A2, wherein the coupling is arranged in a vertical direction and is pushed together by the weight of a tank to which a coupling part is connected. However, in other embodiments the coupling may be held together by a locking mechanism, such as a locking ring arranged to interact with a rib on an outer surface of the connecting sleeve and a rib on the coupling part not arranged in the first end section of the connecting sleeve. Based on the present specification, the skilled person would clearly recognize that the coupling may be held together by numerous technical solutions well known in the prior art.

All the disclosed double poppet valve couplings are highly advantageous in that they are modular in the sense that both the first and the second coupling part may be used as a male or female connector part by simply changing the coupling part connected to the connecting sleeve. The change of which side of the coupling acts as a female/male connector part may also be performed on site without

leakage/spillage.

One of the advantages provided by the modularity of the inventive coupling is that the production is simplified and cost-efficient in that a minimum of different parts needs to be manufactured. Further, the number of spare parts necessary for making any repair is reduced.

A further advantage provided by the modularity of the inventive coupling is that a male connector part may quickly be rebuilt into a female connector part if required. This may be advantageous, for instance if parts of the coupling are damaged. In many situations, this feature will reduce operation downtime. For instance, if a female connector part of the present coupling is damaged, it may usually be repaired by only replacing the connecting sleeve without removing the

corresponding coupling part from the equipment to which it is attached. A similar repair of a prior art coupling will commonly require that the equipment on which the female connector part is attached, e.g. a fluid tank, is emptied of fluids.

The coupling according to the present invention may further be made field serviceable by use of for instance two Allen keys, or other standard tools commonly present. A fourth exemplary poppet coupling is disclosed in figs. 7-10. The coupling features a female coupling half 39 and a male coupling half 38. The female coupling half features a first housing 40, a first poppet element 41 and a sleeve assembly 42. The male coupling half features a second housing 43 and a second poppet element 44. The first housing comprises a connecting end having a connecting recess 45 for receiving a stab connecting part 46 of the second housing. The sleeve assembly 42 comprises a first cylindrical section 47 and a second cylindrical section 48. The cylindrical sections being slidably connected such that the length of the sleeve assembly may vary between a first length LI and a second length L2, the first length being longer than the second length. The first cylindrical section comprises a poppet valve seat 50 interacting with the first poppet element in a first position and an annular surface 55 for interaction with the stab connecting part 46. The poppet valve seat of the first cylindrical section is biased towards the first position by a spring 49. The spring is arranged in an annular space 56, similar to the above described couplings. In the first position, the sleeve assembly has the first length. The second cylindrical section 48 features a poppet connecting end 51, being distal to the first cylindrical section, to which a poppet stem 52 of the first poppet element is rigidly connected. The second cylindrical section 48 comprises at least one fluid passage 53 (i.e. through-hole) in its annular wall. The poppet connecting end 51 is fluid tight.

The stab connecting part 46 features a poppet valve seat 54 interacting with the second poppet element 44 in a first position. The second poppet element is biased towards the first position by a spring (not shown).

In figs. 7a and 7b, the female coupling half and the male coupling half is shown prior to connection of the coupling.

Figs. 8a, 8b and 10a show the coupling during the initial phase of the connection. The stab connecting part 46 of the male coupling half is introduced into the recess 45 of the female coupling half. In the initial phase, the first and the second poppet elements 41, 44 are in contact, while the stab connecting part 46 interacts with the first cylindrical section 47. The poppet valve seat 50 of the first cylindrical section and the second poppet element 44 are in their respective first positions, and the flow path of the coupling is closed during the initial phase.

Figs. 9a, 9b and 10b show the coupling when it is fully connected and features a flow path extending through the whole coupling. After the initial phase, the stab connecting part 46 of the male coupling half is introduced further into the recess 45 of the female coupling half. The stab connecting part will then push the first cylindrical section 47, and consequently the poppet valve seat 50, away from the first poppet element 41, i.e. away from the first position and into a second position. In the second position, the female coupling half is open, i.e. features a flow path extending through the whole coupling half.

At the same time as the first cylindrical section 47 is pushed by the stab connecting part 46, the first poppet element 41 will push the second poppet element 44 away from the poppet valve seat 54 of the stab connecting part 46, i.e. the second poppet element 44 is pushed away from its first position and into a second position. In the second position, the male coupling half is open, i.e. features a flow path extending through the whole coupling half. During the movement of the first cylindrical section 47 towards the second position, the first cylindrical section is arranged to initially slide/move relative to the second cylindrical section, such that the length of the sleeve assembly is reduced from the first length to the second length. The reduction in length is required to allow the first poppet element to push the second poppet element away from the poppet valve seat of the stab connecting part. In addition, the initial movement of the first cylindrical section ensures that a fluid tight connection is obtained between the stab connecting part and the recess before the coupling is fully open. Further, by having the poppet connecting end of the second cylindrical section fluid tight and having the flow path via the holes in the annular wall of the second cylindrical section, the female coupling half features a double seal when closed.