WO2012089246A1

WO2012089246A1 - Vapour recovery pump

Info

Publication number: WO2012089246A1
Application number: PCT/EP2010/070814
Authority: WO
Inventors: Bengt I. Larsson
Original assignee: Dresser Wayne Ab
Priority date: 2010-12-28
Filing date: 2010-12-28
Publication date: 2012-07-05
Also published as: BR112013018755A2; CN103298731B; BR112013018755B1; EP2658806A1; CN103298731A; EP2658806B1

Abstract

The invention relates to a vapour recovery pump (1) for a fuel dispensing unit. The vapour recovery pump (1) comprises a pump housing (2) with a first chamber (3), a second chamber (4) and a third chamber (5), each one of said chambers (3, 4, 5) having a vapour port (8, 9, 12). The first and second chambers (3, 4) being separated by a first piston (6) comprising a first vapour inlet valve (17), and the second and third chambers (4, 5) being separated by a second piston (7) comprising a second vapour inlet valve (18). The first and second pistons (6, 7) are arranged to move reciprocally and out of phase in relation to each other such that the volumes of the chambers (3, 4, 5) repeatedly decrease and increase to allow a flow of vapour between the first and third chambers (3, 5), and the second chamber (4). The invention also relates to a fuel dispensing unit for refueling vehicles.

Description

VAPOUR RECOVERY PUMP

Technical field

The present invention relates to a vapour recovery pump for a fuel dispensing unit, comprising a pump housing with a first chamber, a second chamber and a third chamber. The invention also relates to a fuel dispensing unit.

Background art

When filling the fuel tank of a motor vehicle, it is a common measure to recover the vapour escaping the tank when filling it with liquid fuel. This measure is taken for both safety and environmental reasons, since the fuel vapours are flammable and constitute a health hazard. The vapour recovery is achieved, for instance, by arranging a vapour suction nozzle next to the fuel dispensing nozzle of a pistol grip that is used for filling the tank with fuel.

Vapour is then removed from the tank during filling, at a certain rate, which is often controlled by the standard rate. Vapour recovery systems typically comprise a pump for removing fuel vapour, from the tank of the vehicle, by suction and feeding it back to the fuel container from which the fuel is fed to the vehicle. This mutual exchange of vapour/fuel is continuously performed when filling a vehicle with fuel.

A problem associated with this type of vapour recovery systems is relatively high production costs due to complex arrangements. Maintenance is cumbersome and many of the techniques are sensitive to leakage of vapour past the piston in the pump. Another problem is that some of the

arrangements are rather bulky and takes a lot of space when mounted inside a fuel dispensing unit.

EP 1 783 368, for example, discloses a vapour recovery pump for a fuel dispensing unit, comprising a housing with two chambers each having a vapour inlet valve and a vapour outlet valve, respectively, the chambers being separated by a movable piston arranged to move a distance between a first and a second end position inside the housing for continuously decreasing and increasing the volume of the chambers. A control element is arranged to selectively vary the location of the first end position.

This type of vapour recovery pump solves many of the problems stated above. However, a new problem arises with this type of pump. The movement of the piston causes an undesirable vibration of the vapour recovery pump. The vibration in turn contributes to a noisy vapour recovery system and may expose its surroundings to wear.

Summary of the invention

It is an object of the present invention to provide an improvement of the above technique and prior art. More particularly, it is an object of the present invention to provide a vapour recovery pump and a fuel dispensing unit of improved construction offering lower production costs and a reduced need for maintenance. Further, it is an object of the present invention to provide a vapour recovery pump which causes minimum vibration during use.

These and other objects as well as advantages that will be apparent from the following description of the present invention are achieved by a vapour recovery pump for a fuel dispensing unit according to the independent claim.

Accordingly, a vapour recovery pump for a fuel dispensing unit is provided. The vapour recovery pump comprises a pump housing with a first chamber, a second chamber and a third chamber, each one of said chambers having a vapour port. The the first and second chambers being separated by a first piston comprising a first vapour inlet valve, and the second and third chambers being separated by a second piston comprising a second vapour inlet valve. The first and second pistons are arranged to move reciprocally and out of phase in relation to each other such that the volumes of the chambers repeatedly decrease and increase to allow a flow of vapour between the first and third chambers, and the second chamber. This is advantageous in that the vapour recovery comprises two pistons which due to their movement in relation to each other neutralize any vibration caused by the pistons. Thus, a vapour recovery system having such a vapour recovery pump will operate smoothly and without causing disturbing noise. Yet another advantage is that the pump according to the invention is insensitive to vapour occurring on both sides of the pistons. The pump is easy to produce and requires a low need for maintenance.

The vapour port in the first and third chamber may be a vapour recovery inlet and the vapour port in said second chamber may be a vapour recovery outlet. The vapour is transported into the first and third chambers from via the vapour recovery inlets and out of the second chamber via the vapour recovery outlet.

The vapour port in the first and third chamber may be a vapour recovery outlet and the vapour port in the second chamber may be a vapour recovery inlet. The vapour is transported into the second chamber from via the vapour recovery inlets and out of the first and third chambers via the vapour recovery outlet. Accordingly, the vapour flow thought the vapour recovery pump may be diverted by changing the status of the vapour ports.

The first and second vapour inlet valves may be check valves, which is advantageous in that the vapour only is permitted to travel in one direction.

A check valve may be provided at each one of the vapour ports, which makes it possible to better control the flow through said ports.

Each one of the first and second pistons may comprise a magnetic device and electromagnetic control means may be provided to move the pistons by altering a magnetic field. This is advantageous in that it facilitates a convenient control of the piston. Preferably, the magnetic device is an electromagnet, a permanent magnet or a combination thereof.

Each one of the first and second pistons may be made from a magnetic material. This is advantageous in that it facilitates a convenient control of the piston.

The pump housing may comprise coils fed by a current for moving said first and second pistons, which provides a compact design of the vapour recovery pump.

The second chamber may comprise a coil fed by a current for moving said first and second pistons, and a spring element attached between said first and second pistons. When the pistons are moved toward each other by means of a current fed through the coil, the spring element is compressed. When the current is terminated, the compressed spring element helps moving the pistons back into their idle position.

Each one of the first and third chambers may comprise a coil fed by a current for moving said first and second pistons, and a first spring element may be attached between the first piston and a first side wall of the pump housing in the first chamber, and a second spring element may be attached between the second piston and a second side wall of the pump housing in the third chamber. When the pistons are moved away from each other by means of a current fed through the coils, the first and second spring elements are compressed. When the current is terminated, the compressed spring elements help moving the pistons back into their idle position. Naturally, the number of coils and spring elements comprised by the vapour recovery pump may be varied.

According to a second aspect of the invention, the invention relates to a fuel dispensing unit for refuelling vehicles, comprising a vapour recovery pump according to the above described features. A vapour suction nozzle is connected to the first and third chamber, or said second chamber via a vapour flow line, for transporting fuel vapour.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, etc]" are to be interpreted openly as referring to at least one instance of said element, device, component, means, etc., unless explicitly stated otherwise.

Brief description of the drawings

The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

Fig. 1 a-d are perspective views of a first embodiment of a vapour recovery pump according to a first aspect of the invention, Fig. 2 is a perspective view of a second embodiment of a vapour recovery pump according to the first aspect of the invention, and

Fig. 3 is a perspective view of a fuel dispensing unit according a second aspect of the invention.

Detailed description of preferred embodiments of the invention

Fig. 1 a illustrates a vapour recovery pump 1 having a pump housing 2 comprising a first chamber 3, a second chamber 4 and a third chamber 5. The first and second chambers 3, 4 are separated by a first piston 6 and the second and third chambers 4, 5 are separated by a second piston 7. The first and second pistons 6, 7 are movable in a horizontal direction of the pump housing 2 in order to repeatedly decrease and increase the volumes of the chambers 3, 4, 5 during use of the vapour recovery pump 1 . The first and second pistons 6, 7 move reciprocally and substantially out of phase in relation to each other within the pump housing 2. The volume of each chamber 3, 4, 5 depends on the location of the pistons 6, 7, but the total volume of the chambers 3, 4, 5 is constant. The volumes of the first and third chambers 3, 5 are, however, always substantially equal in relation to each other. The first and third chambers 3, 5 have a vapour recovery inlet 8, 9 to which a vapour inlet line is connected 10, 1 1 . The second chamber 4 has a vapour recovery outlet 12, to which a vapour outlet line 13 is connected. The vapour recovery inlets 8, 9 and the vapour recovery outlet 12 are provided with a check valve 14, 15, 16 in order to ensure a one direction vapour flow. The vapour inlet valves 14, 16 ensure that that vapour flows from the vapour inlet lines 10, 1 1 into the first and third chambers 3, 5, but not in the other direction. The vapour outlet valve 15 ensures that that vapour flows from the second chamber 4 into the vapour outlet line 13, but not in the other direction. The ends of the vapour inlet lines 10, 1 1 not being connected to the pump housing 2 are connected to a fuel nozzle of a fuel dispensing unit. The end of the vapour outlet line 13 not being connected to the pump housing 2 is connected to a fuel reservoir containing fuel. During use of the fuel dispensing unit, vapour is accordingly drawn from the fuel nozzle via the vapour inlet lines 10, 1 1 to the pump housing 2, and from there pressured via the vapour outlet line 13 into the fuel reservoir. The first piston is provided with a first vapour inlet valve 17 and the second piston 7 is provided with a second vapour inlet valve 18. The vapour inlet valves 17, 18 are check valves. The first and second vapour inlet valves 17, 18 ensure that vapour flows from the first and third chamber 3, 5 into the second chamber 4 during use of the vapour recovery pump 1 , but not in the other direction.

Figs. 1 b-1 d illustrate the vapour recovery pump 1 during use. In Fig. 1 b, the first and second pistons 6, 7 are moved towards each other in a horizontal direction within the pump housing 2 of the vapour recovery pump 1 . Thus, due to the increase in volume, and hence reduction in pressure in the first and third chambers 3, 5 vapour is drawn from the fuel nozzle into the first and third chambers 3, 5 through the vapour inlet lines 10, 1 1 via the vapour recovery inlets 8, 9. When the vapour has been draw into the first and third chambers 3, 5, the pistons 6, 7 move away from each other in a horizontal direction within the pump housing 2, as illustrated in Fig. 1 c. The vapour inlet valves 14, 16 prevent vapour from escaping via the vapour inlet lines and the vapour outlet valve 15 prevent vapour from returning into the second chamber 4 via the vapour outlet line 13.

Thus, the vapour is pressed from the first and third chambers 3, 5, via the vapour inlet valves 17, 18, into the second chamber 4. By moving the pistons 6, 7 towards each other once again, the vapour is pressed out from the second chamber 4 through the vapour outlet valve 15 to the vapour outlet line 13 and transported to the fuel reservoir. At the same time, new fuel vapour is drawn into the first and third chambers 3, 5 via the vapour recovery inlets 8, 9, as illustrated in Fig. 1 d.

In Fig. 2, the vapour recovery pump 1 is illustrated according to a second embodiment of the invention. In this embodiment, each one of the first and second pistons 6, 7 comprises a magnetic device 19. An electromagnetic control means 20 is provided to move the pistons by altering a magnetic field. The magnetic field may for example be altered using coils 21 attached to the pump housing 2. The coils are then fed by a current for moving the first and second pistons 6, 7. However, other way of controlling the pistons 6, 7 are naturally also possible. For example, an engine controlled by a control unit may be used.

With reference again to Fig. 2, the electromagnetic control means 20 is connected to plurality of coils 21 arranged around the pump housing 2.

Preferably the coils 21 are integrated in the pump housing 2. During operation of the vapour recovery pump 1 , electrical currents are fed through the coils 21 which generate a magnetic field that attracts the pistons 6, 7 or more specifically, attracts the magnetic devices 19 in the piston 6, 7. By feeding electrical currents through coils 21 near the outer sides of the pump housing 2, the pistons 6, 7 are moved towards the outer sides. When the pistons 6, 7 are near the outer side, electrical currents are fed through coils near the centre of the pump housing 2, which causes the pistons 6, 7 to move towards each other and the centre of the pump housing 2. By repeatedly and rapidly altering current levels in the coils 21 , the pistons 6, 7 are moved back and forth.

In Fig. 3, a fuel dispensing unit 22 according to a second aspect of the invention is illustrated. Basically, when filling a vehicle by means of the fuel dispensing unit, the rate of dispensed fuel is measured by a fuel meter. A control device monitor the rate of dispensed fuel and sends a signal to the vapour recovery pump 1 setting the vapour recovering rate, or pumping rate, to be equal to the fuel dispensing rate. If a detector detects a predetermined, low level of hydrocarbon content, the vapour recovery pump 1 is stopped.

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended claims.

Accordingly, the size and shape of the vapour recovery pump and the fuel dispensing unit according to the present invention may be varied in a vast number of different embodiments without deviating from the scope of the invention.

Claims

1 . A vapour recovery pump (1 ) for a fuel dispensing unit (22), comprising a pump housing (2) with a first chamber (3), a second chamber (4) and a third chamber (5), each one of said chambers (3, 4, 5) having a vapour port (8, 9, 12), the first and second chambers (3, 4) being separated by a first piston (6) comprising a first vapour inlet valve (17), and the second and third chambers (4, 5) being separated by a second piston (7) comprising a second vapour inlet valve (18), wherein the first and second pistons (6, 7) are arranged to move reciprocally and out of phase in relation to each other such that the volumes of the chambers (3, 4, 5) repeatedly decrease and increase to allow a flow of vapour between the first and third chambers (3, 5), and the second chamber (4).

2. A vapour recovery pump (1 ) according to claim 1 , wherein said vapour port (8, 9) in said first and third chamber (3, 5) is a vapour recovery inlet (8, 9) and said vapour port (12) in said second chamber (4) is a vapour recovery outlet (12).

3. A vapour recovery pump (1 ) according to claim 1 , wherein said vapour port (8, 9) in said first and third chamber (3, 5) is a vapour recovery outlet (8, 9) and said vapour port (12) in said second chamber (4) is a vapour recovery inlet (12).

4. A vapour recovery pump (1 ) according to any one of the preceding claims, wherein said first and second vapour inlet valves (17, 18) are check valves.

5. A vapour recovery pump (1 ) according to any one of the preceding claims, wherein a check valve (14, 15, 16) is provided at each one of the vapour ports (8, 9, 12).

6. A vapour recovery pump (1 ) according to any one of the preceding claims, wherein each one of said first and second pistons (6, 7) comprises a magnetic device (19). 7. A vapour recovery pump (1 ) according to any one of claims 1 -5, wherein each one of said first and second pistons (6,

7) is made from a magnetic material.

8. A vapour recovery pump (1 ) according to claim 6, wherein electromagnetic control means (20) being provided to move the pistons (6, 7) by altering a magnetic field.

9. A vapour recovery pump (1 ) according to claims 6 or 7, wherein the pump housing (2) comprises coils (21 ) fed by a current for moving said first and second pistons (6, 7).

10. A vapour recovery pump (1 ) according to any one of claims 6-9, wherein the second chamber (4) comprises a coil fed by a current for moving said first and second pistons (6, 7), and a spring element attached between said first and second pistons (6, 7).

1 1 . A vapour recovery pump (1 ) according to any one of claims 6-10, wherein each one of the first and third chambers (3, 5) comprises a coil fed by a current for moving said first and second pistons (6, 7), and wherein a first spring element is attached between said first piston (6) and a first side wall of the pump housing (2) in the first chamber (3), and a second spring element is attached between said second piston (7) and a second side wall of the pump housing (2) in the third chamber (5).

12. A fuel dispensing unit (22) for refueling vehicles, comprising a vapour recovery pump (1 ) according to any one of the preceding claims, wherein a vapour suction nozzle is connected to said first and third chamber (3, 5), or said second chamber (4) via a vapour flow line, for transporting fuel vapour.