WO1997028083A2

WO1997028083A2 - System for limiting the loss of vapour from petrol storage and delivery installations

Info

Publication number: WO1997028083A2
Application number: PCT/GB1997/000295
Authority: WO
Inventors: Barry Charles Risbridger; Paul Richard Chawner
Original assignee: W. & J. Risbridger Limited
Priority date: 1996-02-02
Filing date: 1997-01-31
Publication date: 1997-08-07
Also published as: WO1997028083A3

Abstract

A petrol vapour recovery system is disclosed for minimising the loss of petrol vapour during supply of fuel to a vehicle and during supply of fuel to a reservoir tank from a road tanker. The system includes a valve (112) for use in a fuel delivery system which comprises a valve body having two connected parts (114, 118) which are severable from one another if the valve body sustains a physical bending movement, each of said connected parts having a valve (120, 121) mounted therein which is normally open, the valves being arranged to close automatically in the event that said connected parts are severed or damaged.

Description

SYSTEMS FOR LIMITING THE LOSS OF VAPOUR FROM PETROL STORAGE AND DELIVERY INSTALLATIONS

This invention relates to systems for limiting the loss of vapour from petrol storage and deHvery systems.

It is becoming increasingly a requirement that dispensing of fuel to motor vehicles should be accompanied by recovery of vapour displaced during the filling operation. Therefore, the petrol deHvery pump, in addition to having a fuel deHvery Hne from an underground fuel tank, wiU also include a vapour recovery line which is plumbed into the vapour vent Hne ofthe underground storage tank itself.

There are also continuing environmental pressures to reduce the escape of vapours of fuels such as petrol and diesel oil during delivery from a tanker such as a road tanker. It is now the practice for road tankers to be connected to an underground fuel tank by two hoses during the filling operation. The first of these hoses transfers fuel from the road tanker through the filling Hne to the tank, while the second line is connected to a line connected to the head space of the tank and recovers vapour which is displaced from the tank during the deHvery of the fuel. Despite this system, vapour can escape during the filling operation and the primary object of this invention is to reduce or eliminate such escape.

Another area of concern is the possible escape of vapour from the fuel filling station in the event that a fuel deHvery pump is damaged, e.g. by a colHding vehicle. In such a case, the vapour recovery line at the pump may be severed and vapour can escape, thereby causing a health and fire risk.

It is therefore one object of the present invention to provide a valve for a fuel deHvery system which automatically disconnects the vapour recovery Hne to the pump in the event of physical damage to the pump. According to one aspect of the present invention there is provided a valve for use in a fuel deHvery system which comprises a valve body having two connected parts which are severable from one another if the valve sustains a physical bending movement, each of said connected parts having a valve mounted therein which is normally open, the valves being arranged to close automaticaUy in the event that said connected parts are severed or damaged.

A second object ofthe invention is to provide a hose coupHng for connecting a road tanker fuel hose to a fill conduit of a fuel storage tank which obviates the danger of loss of vapour when supplying fuel to the storage tank.

According to a second aspect of the present invention there is provided a hose coupling, especially for connecting a road tanker fuel hose to a fill conduit of a fuel tank, said coupHng comprising a first part adapted for connection to the fill conduit or the tanker hose and a second part adapted for connection to the other ofthe hose and the fill conduit, said first part incorporating a valve biased into its closed position, and the second part having a movable probe which in its extended position is capable of opening the valve and means for extending the probe to open the valve after said two parts have been coupled together.

As a result ofthe improved coupHng described above, vapour or fuel cannot be forced out of the offset fill Hne until a hose is coupled onto the fill Hne and wϋl then flow back to the tanker.

Another point at which vapour is sometimes leaked to the atmosphere is from the vapour recovery Hne. There have also been problems in vapour leakage since the tank remains connected to a vapour vent Hne when the tank is connected to a vapour recovery hose of a road tanker. The problem of vapour escape may also arise because pressure may build up in the tank and this is released when the tanker hose is connected to a vapour vent Hne having an overpressure reHef valve. The above problem may be overcome in accordance with this mvention by providing a coupHng for connecting a vapour recovery hose to a vapour vent line from a fuel tanker, said coupling comprising a part connected to the vapour vent Hne and having a first valve operable by a probe on the hose coupHng when the hose coupHng and the vent Hne are coupled together, a second valve which in a first position connects the head space of the tank to a vent pipe to atmosphere and in a second position connects the head space to said first valve, the first and second valves being interlocked so that the first valve cannot be opened to connect the head space with the vapour recovery hose, while the second valve is in its first position.

OccasionaUy, it is helpful to have some indication during the unloading of a road tanker of the rate of flow of vapour back to the tanker. A low rate of flow may, for example, be indicative of vapour leaking from elsewhere in the system. The invention, therefore, further provides a simple flow indicator which may be interposed between the vapour vent Hne and the tanker. Conveniently, it is housed in a separate unit which is fitted between the vapour vent Hne and the tanker hose.

Further features and advantages of the present invention wiU be apparent from the foUowing description and accompanying drawings, in which :-

Figure 1 is a schematic view of a fuel t^ik storage and deHvery system,

Figure 2 is a section through one part of a coupHng for fitting to the fiU line of an underground fuel tank,

Figure 2A is an end view of the tanker half coupHng for fitting to the coupHng part shown in Figure 2,

Figure 2B is a section along the Hne A-A in Figure 2A,

Figure 3 is a section through a fitting for attachment to the end of a vapour vent Hne

Figure 3 A is a section along the Hne A-A in Figure 3, Figure 4 is a view partly in section of a coupHng which incorporates a vapour flow detection device, and

Figures 5 and 5A are elevations of a frangible valve in accordance with the invention for connecting a fuel supply Hne to the pump.

Referring to Figure 1 ofthe drawings, this shows a fuel tank installation having an underground fuel tank 1 which is connected via an offset fuel line 2 to a filling access point 3, and to a suction line 4 to a petrol pump 5 for deHvering fuel to retail customers. The head space 6 ofthe tank is vented via a vapour vent Hne 7, either to a single vent Hne 8 or more usuaUy in modern installations to a manifold 9 which is connected to a number of other underground fuel tanks. The manifold 9 includes a vent pipe 10a through which aU the manifold vent lines can vent to atmosphere, and also to a fitting 1 1 through which vapour can be recovered back to a road tanker during off-loading of fuel to the underground storage tank. The vent pipes 8 and 10a usually include a pressure reHef valve 12a, 12b, which is set to release vapour to atmosphere at a low over-pressure of about 1~2 psi. The couplings and other fittings to be described and which relate to the present invention are intended to be fitted to points 3 and 11 ofthe fuel tank installation.

Referring first to Figures 2, 2A and 2B, these iUustrate the two parts of an adaptor and hose coupling which wiU be connected at the unloading point 3. Figure 2 is a section through an adaptor 20 which wiU be fitted to the end ofthe offset fuel line 2. Adaptor 20 comprises a body portion 21 threaded at 22 for attachment to the end of the offset fuel Hne and fitted with a poppet valve 23 whicn is spring-biased into its closed position, seating against a curved or other corresponding shaped face 24 of the inlet port 25 ofthe adaptor. Valve 23 includes a spindle 26 designed to shde axiaUy in a bore in a projection 27 in the direction ofthe arrow to open the valve. The valve is designed to be opened by a probe fitted to the tanker hose once the two parts ofthe coupHng are brought together. However, in order to prevent any pressurised vapour or fuel in the offset or direct fuel Hne from escaping during the coupHng operation, the hose coupling is designed so that valve 23 is only manually operable once the coupHng is securely made.

Referring to Figures 2A and 2B, the half of the coupHng which is fitted to the tanker hose comprises a body portion 30 having suitably shaped grooves 31 for connection to a hose and latches 32 for engagement in a groove 28 of the part 20 for coupHng the parts together. The hose coupHng part 30 incorporates a probe 33 which in its extended position is able to open the valve 23 by pushing on the face of the poppet valve. However, in the position shown in Figure 2B, the probe 33 does not quite touch the face ofthe poppet valve when the two halves are coupled together.

After the coupHng has been connected, the probe 33 can be extended by rotating a spindle 34 which is geared to e.g. a worm 35 on the probe 33. This causes the probe 33 to be extended, thus pressing open the valve 23 and aUowing vapour to flow from the offset fiU Hne 2 into the tanker hose and back to the tanker. Spindle 34 is movable by operator lever 36 which is attached to the end ofthe spindle.

After the required amount of fuel has been off-loaded into the underground fuel tank, the probe 33 can be operated once more by returning it to its original position, thus closing the valve 23 and preventing any escape of vapour before the coupHng is dismounted and returned with the hose to the tanker.

Figures 3 and 3A, show a device for connection to the vent Hne manifold at the point 1 1 shown in Figure 1. The device comprises a body 50 having a threaded recess

51 for connection on the end o the vent Hne manifold 9. The body includes a port

52 for connection to a vent Hne such as 10 as shown in Figure 1. At the right-hand end of the fitting as shown in Figure 3, a poppet valve 55 normaUy closes off access to the vapour Hne and is spring-biased with a spring 56. Valve 55 includes a spindle 57 which extends back into the body of the adaptor. Valve 55 seats against a surface of the port 53 in an analogous manner to the poppet valve 23 in the coupHng shown in Figure 2. It is envisaged that in use, a tanker's vapour recovery hose would be fitted with a coupHng siπήlar to that shown in Figure 2B, so that the coupHng shown in Figure 2B could be connected to the end 54 ofthe body 50 and, on operating the probe 33, cause the valve 55 to open so that the vapour vent manifold is connected via the vapour recovery hose back to the tanker.

The interaction of valve 55 and the coupHng shown in Figure 2B prevents vapour escaping to atmosphere from the vent Hne 7 or manifold 8, while the tanker recovery hose is being connected to the end 54 of the coupHng shown in Figure 3. Once this connection has been made, the lever 36 can be operated to place the interior of body 50 in communication with the tanker recovery hose.

In order to prevent escape of vapour through the vent Hne to atmosphere during the fi ing of the fuel tank, a second valve 58 is provided within the body 50. Valve 58 is a sleeve valve comprising a sleeve 59 which is shown in the closed position in Figure 3. In this closed position, vapour may flow from the manifold 9 through the body 50 and (if valve 55 is open) into the vapour recovery hose. In this position of valve 58, poppet valve 55 can be opened by operating lever 36 because the spindle 57 can move towards the right, as shown in Figure 3, without impinging on the spindle 60 which forms the central position of valve 58.

It wiU be appreciated that when valve 58 is in its closed position, vapour cannot escape along vent Hne 10 because the sleeve 59 covers the access to port 52. However, in order to protect the tank against possible damage caused by a sudden and excessive pressure buUd-up, an over-pressure reUef valve 61 is provided in the sleeve 59. Pressure reHef valve 61 may, for example, be set to open at a pressure of about 3 psig.

Valve 58 has an open position in which the sleeve 59 is moved to the right (as shown in Figure 3). The position of the spindle 60 is shown in dotted lines in the open position of the valve and it wiU be observed that in this position, the spindle 60 abuts the end of valve stem 57. Because of this abutment, poppet valve 55 cannot be opened while the sleeve valve 59 is open. Therefore, unloading of fuel into the tank 1 cannot commence until the sleeve valve 58 is moved to its shut position. Movement of valve 58 between shut and open positions is effected by operation of lever 62. Lever 62 carries a pinion 63 which engages a rack 64 formed on the outside of spindle

60. It wiU be appreciated that the normal position of valve 58 is in the open position and lever 62 may be locked, e.g. with a padlock, in this position so that in normal operation of the fuel tank installation, the tank can breathe through the vent pipe 8 or 10.

Referring to Figure 4, this shows a coupHng which it is intended to be fitted between the coupHng point 11 and the tanker hose. Conveniently, the coupHng would be an additional temporary test section fitted to the end of the tanker hose, although it could be incorporated as part of the vehicle vapour recovery hose. The coupHng comprises a body 70 at one of which are coupHng latches 71 similar to those shown in Figure 2B.

The device also includes a probe 72 for opening a valve such as valve 55 in the fitting shown in Figure 3. The other end 73 of the adaptor incorporates a spring- biased poppet valve 74 which is similar in construction to valve 55 shown in Figure 3. Accordingly, the adaptor can be attached to the end 54 of the fitting 50 and the valve opened by the probe 72, and the other end 73 of the adaptor can be coupled to a coupHng such as shown in figure 2B of a tanker vapour recovery Hne. The fitting includes a vapour flow indicator 76 within the body 70 (viewable through a viewing glass 79) and comprising a swinging flap 77 which moves in response to vapour flow along the fitting. A scale 78 may be provided to give a measure ofthe amount of vapour flowing through the vapour recovery Hne.

Referring again to Figure 1 , at the point of deHvering the fuel to a motor vehicle from the deHvery pump 5, a deHvery hose and nozzle (not shown) may be used which can be sealingly engaged with the vehicle fuel tank. Such deHvery hose may include an inner deHvery tube and an outer annular coaxial tube for recovering vapour. One typical system of this kind is avaUable from Dover International BV of Zwaneburg, the Netherlands and is sold as the OPW 11-VF Vapour Recovery Nozzle. WhUe the fuel is being deHvered to a vehicle, vapour is taken back to the vapour vent Hne 8 via the line 7 or back to the storage tank.

There are two problems with this system. First, if the deHvery pump is damaged in an accident, the vapour recovery Hne may be broken and vapour wUl be aUowed to escape from the underground fuel tank to the atmosphere, causing an immediate and serious fire risk. A second problem is that there is a need from time to time to test the integrity of the vapour vent lines, usuaUy by making a pressure test. This cannot be made if the vapour recovery line 7 is open.

The present mvention provides a solution to these problems and this is described in the accompanying Figures 5 and 5 A.

Referring to Figures 5 and 5 A, a valve 112 is located beneath the petrol pump at 5a to control the vapour recovery Hne 7. The valve comprises a body 114 manufactured in two housing parts 116 and 118, which are joined or latched together at 117 in fluid-tight re-useable manner. Two longitudinaUy spaced valves 120 and 121 are mounted Vvithin the body. Valves 120 and 121 have respective valve stems 119a and 119b which normaUy butt against each other at a point 123, which is located in the region of the joint between the housing parts 116 and 11 . Thus, in the event of a collision, the housing part 116 wiU break away from the lower part 118 and the valves 120 and 121 wiU both close in opposite directions under the influence of springs 125 and 128.

An eccentric cam 124 extends through the lower part of the body 118 and in the normal working position, does not contact the valve spindle 119. Springs 125 and 128 tend to urge the valve stem 119b in opposite directions. However, the relative strengths of the springs are selected so that both valves are raised off their valve seats so that vapour may flow in the direction ofthe arrow from the dispenser back into the tank. Alternatively, the spring 125 is stronger than spring 128 and tends to push the stems 119a, 119b downwardly. The valve 120 is prevented from closing onto its seat by the stem 119b abutting the surface of the cam 124. However, in the event that the valve is damaged, e.g. by a collision, and the top portion 1 16 is broken off, the lower valve 121 is no longer restrained by the upper part ofthe valve and wiU automaticaUy close onto the seat 126 under the action of spring 128.

If the top part 116 of the valve is broken off, it remains connected to the fuel dispenser. However, in the absence ofthe restraint imposed by the cam surface and/or the spring 128, valve 120 wiU close onto its seat 130 and wiU prevent vapour escaping from the fuel dispenser.

Should it be desired to pressure test the Hne 7 back to the tank, such a pressure test can be made through the port 127 in the lower part of the housing 118. In order to make such a test, the eccentric cam is turned so as to push the spindle 119 upwardly against the action ofthe upper spring 128, thereby closing the lower valve 121 against its seat 126. A pressure test can then be made through the test port 127. Such a pressure test can be conducted using the technique and apparatus described in UK Patent Apphcation No. 9306893.0 (PubHcation No. 2265988) or by similar methods. As indicated in Figure 5 A, the valve body may be grooved, e.g. at 131 for attachment by IF bolt fixing or provided with four apertured lugs 132 for through bolting into the base ofthe deHvery pump and subframe.

This invention also includes a float valve for automaticaUy closing a pipe from a Hquid tank.

Float valves are widely used to cut off the flow of Hquid or vapour from a storage tank when the Hquid level reaches a predetermined point. Valves of this type are frequently used in fuel storage tanks and are instaUed on the vapour vent line to automaticaUy shut off the flow of Hquid into a tank and to restrict the flow of vapour back to the deHvery vehicle when the storage tank has reached a desired fiU level.

One of the difficulties with such valves is that they can close very suddenly which causes the transmission of severe hydrauHc shocks through a fuel deHvery system

According to one aspect ofthe present invention there is provided a float valve comprising an elongated float movable within a tube and having a conicaUy or part conicaUy shaped valve seat.

As a result of the design, the improved valve graduaUy closes in a non- concussive manner.

One embodiment of a float valve in accordance with the mvention wiU now be described with reference to the further accompanying drawings, in which:-

Figure 6 is a section through a float valve in accordance with the invention.

Referring once again to Figure 1, the fuel storage and deHvery system comprises a storage tank 1 containing a Hquid fuel. The storage tank is connected to an off-set fiU Hne 2 (or direct fiU point) through which fuel can loaded into the tank via a fuel fiU point 3. Fuel from the storage tank can be deHvered to a deHvery pump 5 via a suction Hne 4 and vapour can be vented from the storage tank through a vapour vent Hne 6 which may be connected either to a single vent Hne 7 or a vent Hne manifold 8, connected to several other fuel tanks. The vent Hne 6 A may also include a branch Hne 6a connected to the deHvery pump and intended for vapour recovery from fuel dispensed into a vehicle.

The float valve 10 is located within the ullage 6 of the tank and is fitted to the lower end of the vapour vent line 7. Float valve 10 is intended to close the vent line when fuel in the tank rises to a predetermined level. This prevents over-fiUing of the fuel tank.

The details of he float valve itself are shown in Figure 6 and it wiU be seen that the valve comprises a body 220 of generaUy tubular form having an upper threaded end 221 for screwed attachment to the vent Hne pipe 6 or to a suitable adaptor. SHdably contained within the tube 220 is a float 222, designed to move upwardly in the tube 220 as the Hquid level rises in the tank towards a fiUed condition In order to prevent fuel being driven out of the tank by over filling, the valve 10 is set to close when there is stUl a sufficient free head space at the top ofthe tank, e.g. when the tank is about 95% filled. Tube 220 is formed with one or more axiaUy elongated slots 224 in the waU of the tube through which vapour may flow from the ullage through the vent pipe. As the float 222 moves up the tube 220, it reduces the area of the slots 224 through which the vapour is free to flow thereby graduaUy restricting the flow of vapour through the vent Hne.

The top of the float valve at 226 is tapered or frusto conical in shape to correspond with a similar tapered or frusto conical shape 228 on the upper inner face ofthe tube 220. In the closed position, surfaces 226 and 228 coπespond to close off the valve.

In order to prevent the float valve falling out of the tube when the Hquid in the tank faUs substantiaUy below the level of the float, a float stop pin 230 is provided which extends radiaUy from the float into one or more ofthe slots 224. Thus, at its furthest extent, the float valve is retained by the stop pin engaged in the lower part of the radial slot.

Figure 7 shows an alternative embodiment of float valve in accordance with the invention. The valve is also intended to be mounted in the head space of a fuel storage tank 1. The valve of Figure 7 consists of a tubular valve body 330 having a slot-shaped opening 331 to aUow vapour to escape from the tank into the vapour recovery line 7. A float 332 is aπanged to sHde up and down to control the size of the opening 331 as the Hquid level in the tank changes. However, instead of sHding within the tubular body as in Figure 6, the float sHdes over the body and forms an external sleeve valve. The float has a partition 333 and the tubular body a deflecting cone 334 forming a chamber 335, which damps the movement of the float. At its lower end, the tubular body has an enlarged and chamfered end 336 for guiding the float. A float stop pin 337 is attached to the lower end of the body and extends radiaUy through a slot 338 in the float body.

The float valve may be used in a fuel deHvery system as described in UK Patent Apphcation No. 9306893.0 (PubHcation No. 2265988). A valve such as shown in Figures 4A and 4B of the above apphcation can be fitted in the pipe connecting float valve 10 to the vapour lines 6 and 6A, thereby enabling the vapour lines to be isolated and their integrity tested in the manner described in our above-mentioned apphcation.

Claims

CLAIMS -

1. A valve for use in a fuel deHvery system which comprises a valve body having two connected parts which are severable from one another if the valve body sustains a physical bending movement, each of said connected parts having a valve mounted therein which is normaUy open, the valves being arranged to close automaticaUy in the event that said connected parts are severed or damaged.

2. A valve as claimed in claim 1 wherein the connected parts are adapted to separate under a physical impact which is insufficiently severe to cause damage to the connected parts, whereby at least one of the valves and its associated housing part is re-useable.

3. A valve as claimed in claim 1 or 2 wherein the valves each have valve stems and are mounted in the valve body with their valve stems aHgned and abutting in the region where the two connected parts ofthe valve body are joined.

4. A valve for use in a fuel deHvery system which comprises a valve body having two connected parts which are severable from one another if the valve body sustains a physical bending movement, each of said connected parts having a valve mounted therein which is normaUy open, the valves being arranged to close automaticaUy in the event that said connected parts are severed or damaged.

5. A coupHng for connecting a vapour recovery hose to a vapour vent line from a fuel tanker, said coupling comprising a part connected to the vapour vent Hne and having a first valve operable by a probe on the hose- coupHng when the hose coupHng and the vent line are coupled together, a second valve which in a first position connects the head space of the tank to a vent pipe to atmosphere and in a second position connects the head space to said first valve, the first and second valves being interlocked so that the first valve cannot be opened to connect the head space with the vapour recovery hose, whne the second valve is in its first position.

6. A float valve, especiaUy for controlling a vent Hne from a tank containing Hquid, said valve comprising an elongated float movable on a tubular body, wherein upward movement is damped by pressure of vapour within the tubular body at least just prior to the valve closing onto its seat.

7. A float valve, especiaUy for controlling a vent Hne from a tank containing Hquid, said valve comprising an elongated float movable on a tube which has an opening extending longitudinaUy of the tube, the opening permitting vapour to pass from the tank to the vent Hne and being progressively reduced in area as the float is moved up the tube in response to increasing Hquid level in the tank.

8. A float valve, especiaUy for controlling a vent line from a tank containing Hquid, said valve comprising a float arranged to shde over a tubular body and including a chamber formed by a wall ofthe float and a partition across the tubular body, said chamber being reduced in volume as the valve closes, thus exerting a damping action on the closure ofthe valve.