GB2294773A - An elbow connector for use in testing fuel suction lines - Google Patents

Description

2294773 1 TESTING OF FUEL SUCTION LINES This invention relates to a method

of testing the integrity of a fuel suction line and between a fuel storage tank and a delivery pump. The invention also includes an elbow connector for connecting a fuel tank to a suction line and a fuel supply installation which facilitates the making of such tests.

At a filllnQ station for dispensing petroleum fuels. one or more underground fuel tanks are frequently connected through pipe work running underground to emerge at a pump from which the fuel is dispensed, e... to vehicles. Normally, a fuel supply conduit from the tank rises into an inspection pit accessible by a manhole cover. Located within the pit is an angle check valve which connects the rising supply conduit with a suction pipe leading to the pump. Because the suction fuel line runs underground, often for considerable distances, there is a risk that fuel can leak into the ground from a pipe joint leak or fracture and cause pollution or risk of explosion before it can be detected. Recently, regulations have been proposed for the installation of underpump check valves which ensure that any fuel line leakage would cause the fuel to drain back into the tank and not leak into the ground. Such an underpump valve should also have proMion for an externally operated device to lift the valve poppet and allow the fuel to drain back into the storage tank without spillage. A major difficulty, however, arises with this kind of system. This is that when using conventional pipe fittings, it is difficult to test the integrity of the fuel suction line which runs from the angle check valve to the pump. An additional problem is that solid particles tend to be drawn up by the pump into the underpump valve when operating the pump. These particles may cause the valve to jam open and allow the line to drain back when the 1 2 pump is switched off. The pump must then be reprimed before It can be used again.

The present invention seeks to overcome the above difficulties and also provide a convenient method of testing the integrity of the suction line extending between the tank and the dispensing pump, for testing the tank itself and also lines C from the tank to a venting stack or vapour recovery system.

Accordinu to one aspect of the present invention there is provided an elbow connector for connecting a fuel tank to a suction line serving a fuel dispensing pump and for use in pressure testing the suction line, said connector comprising a body having an inlet port for connection to a feed conduit from the tank, a supply port for connection to the suction line, an access port and a plug which can be introduced through the access port and which is movable under the action of a spring to clo, c the inlet port and enable the suction line to be pressure tested.

The invention also includes a fuel supply installation which comprises a fuel tank, a fuel delivery pump and a suction line between the tank and the pump, an elbow connector which is connected to the tank via an inlet port and to the suction line via a supply port, and an underpump valve located between the pump and the elbow connector for isolating the pump ftom the suction line, the elbow connector having a plug for temporarily closing the inlet port while testing the integrity of the suction line, the underpump valve having a testing port connectable to portable testing apparatus for pressure testing the suction line According to a preferred aspect of the invention the means for temporarily plugging the inlet port of the elbow is remotely operable.

=W W j Preferably, the testing ports for connection to the pressure testing device at Z the underpump valve and/or the elbow connection on the suction line.

Preferably, the elbow comprises the valve body of an angle check valve which is adapted for the purposes of this invention.

Various embodiments of the present invention will now be described with reference to the accompanying drawings, in which.- Figure I is a schematic view showing an undergTound fiiel storage tank-, the suction line connecting it to a petrol pump and the connections to a vent line and an offset fill line; Figures 2 and 2A are diagrammatic views of the portable pressure testing device; Figures 3), 3A, 3B and 3C are views of a test elb)w and test plug for temporarily plugging the inlet port of the elbow; C Figure 3D is a view of the test elbow of Figure.33 with a filter installed; Figure 3E shows a test elbow which is slinilar to that shown in Figure 3, intended to be used with a threaded test plug; Figure 33F shows a test plug suitable for use with the elbow of Figure 3E, Figure 3G shows a modification of the test elbow shown in Figure 3; 1+ Figures 4A and 4B are views of an elbow fitted with means for plugging the inlet port using a device which is remotely operable; Figures 5 and 5A show an underpump check valve fitted with a closure device for closing off the valve for testing the integrity of the suction line; and Figures 6 and 6A show a vent pipe shut off and test valve.

Referring to Figure I of the drawing, a fuel tank 1 is connected via a supply line 3a, an elbow 3 and suction line 2 to a dispensing pump 5. An underpump valve 6 is fitted with an externally-operable shut-off device enabling the line 3a to be isolated from the pump, and the lines 2 and 3a drained back into the tank. The underpump valve, of which a preferred embodiment is described later, may have a valve poppet which can be closed by a system of cams, levers,' screws or other devices which are operated externally of the valve.

The elbow 3 may be the body of a check valve and the internal parts of which have been removed on fitting the underpump valve 6. The check valve body is utilised as shown in Figures 3 to 3F, or 4 and 4A, to accept a plug which can be used to temporarily close off the inlet port 10 of the elbow. The construction of these valves will be described in.more detail later in this specification.

Referring further to Figure 1, the tank 1 is connected to a vent line 7, which can be closed off at a valve 8. Valve 8 includes a closable testing port accessible to the vent line on the tank side of the vent line, so that it can be connected to a portable pressure- testing device so as to pressuretest the tank.. The closure valve 8 is preferably operated by a secunty key or lock so that it cannot be closed by any unauthorised person.

As an alternative, the vent pipe 7 may be one of a number of vent pipes 7a, b and c, each connected to a storage tank, which are connected together to form a manifold which is connected to means for vapour recovery. The manifolded vent lines may have individual closure valves or all be controlled together with a single closure valve.

The tank is also connected to an offset fill line 9 for replenlishing the tank via an elbow 10.

Refening to Figures 2 and 2A, these show two views of the portable pressure testing device. The pressure testing device includes a pressure gauge 20 and a connection point 21 for connecting the gauge to a testing point in the tank pipework. A nipple 22 is provided for connection to a pressure fluid source such as a nitrogen bottle or a compressed air line and valves 23 and 24 for connecting the nitrogen bottle to the line to be tested and for connecting that line to the pressure gauge.

(0 The test panel of the pressure-testing device also includes a pressure relief valve which is set to limit the test pressure applied to the tank or fuel pipework, e.g. to about 1 barg in order to avoid applying excessive pressure to the system. The valves 23 and 24 allow the selected pressure to be applied to the line under test from the source of fluid under pressure and then the line to be isolated so that any leaks can be detected by a drop of pressure on the pressure gauge.

Referring to Figures 3 to 3C, these show a fizst embodiment of a test elbow which may be used in the suction line or filling line for the tank. The elbow comprises a body 120 which may the body of an existing angle check valve, the valve components of which have been removed an installation of the underpump valve. The body 120 has an inlet port 121 connected to the supply line 3a from the tank and an outlet port 122 for connection with the Suction line 2. In normal use, the upper port 123 of the elbow is closed with a cap 124, which is threadably received in the port 23 and is sealed with an 0-ring 25. A stud 26 is received in a threaded bass 27 to seal the elbow.

In order to temporarily close off the port 121 in order to test the integrity of the suction line, a test plug 28 is provided for insertion into the test elbow. Test plug 28 comprises a plunger port-ion 29 attached to a 7 hexagonal cross-section rod, the rod 30 being sized so that it can pass freely through the threaded hole normally occupied by the sealing plug 26. The plunger portion 29 Includes a land 31 and a projecting face 33. Projecting face 33 is dimensioned to enter the upper part of the port 21 with the land 31 engaging on flange 32 of the inlet port.

In order to plug the inlet port 121, cap 124 removed together with the sealing plug 26. Test plug is introduced into the body 120 so that land 31 seals on the top surface of flange 32. With the sealing plug 26 removed, cap 124 is reinstalled so that the cap slides over the rod 30, which projects through the top of the hole in the boss 27. Spring 34 engages in the recess 36 and the movement of screwing down the closure cap 24 causes the spring 34 to be compressed and the flange 31 pressed into contact with the flange 32, thereby sealing the line 3a and isolating the suction line 2 from the is 28 PUMP - As mentioned above, the rod 30 is sized so that it does not completely fill the port within the bass 27. This allows a fluid-tight connection to be made to the hole through the boss 27, thus allowing the line 2 to be tested for integrity through this outlet. Alt-ernatively, a cap may be fitted over the port through the boss 27 in order to seal the connection and allow the test for the 1 8 integrity of the line 2 to be made at the underpump, valve or through a separate access point in the cap 124.

On completion of the test, the cap 124 is again unscrewed and the plug 28 removed. The projection of the stud 30 through the cap 24 is a visible reminder that the line is under test. The sealing plug 28 can be removed and put aside for use in the future or discarded. In one embodiment, a spring of about 10 to 11 p.s.i. is used. The strength of the spring is selected so that it will Yield If excessive pressure is applied to the tank during testing of the integrity of the tank to be described in detail later in this specification. As shown in Figure -331), the spring '34 can be used to retain a filter 11 - 3 3 within the flange 3 2 during the normal use of the elbow, i.e. after a test has been completed and the suction line is in use, and it will be appreciated that in use, the spring 34 holds the flange 1-332 in firm contact with flange 332. The filter mesh openings are large enough to remove fine particles without significantly reducing flow to the pump. The conical shape of the filter elves an effective larger filter area.

Instead of employing a spring to maintain the sealing plug in engagement with the flange 32, it may in some cases be possible to use a threaded test plug where the flange is internally threaded or a thread can be 9 conveniently formed on the flange (see Figures 3E and F). A test plug with a corresponding shaped threaded can then be fitted using the hexagonal shaped stud to screw the test plug home (see Figure 3F).

Figure 3G shows a modification of the elbow of Figure 3. In Figure 3, the test plug 30 is held in place within the elbow by spring 34 and a sealing plua 26 is about to be fitted over the projecting stud 30. The cap 124 shown in Figure 3G is slightly modified in a way designed to prevent a check valve mechanism being refitted. It will be seen also that the stud 30 in this embodiment is circular in cross-section and there is a substantial gap between the stud and the hole through the cap 124.

In the embodiment of Figure 3G, the test cap 124 is screwed onto an upper flange 42, using bolts 40 and 41. A ring-like adaptor plate 43 is sandwiched between the cap 124 and the valve body 120. 0-ring seals are provided between the adaptor ring,.the_upper flange 42 and the cap assembly 124. At least one of the securina bolts 40 is of a kind which shears off when subjected to a torque about a predetermined value. The twist-off torque value of bolts 40 is selected so that the bolts can be tightened sufficiently to compress the 0-ring seal between the adaptor and the upper flange of the body 120, to produce a fluid-tight seal. The head of the bolt, such as 40, then 1 40 twists off leaving a stub portion of a head 44 in a recess in the adaptor ring, and a threaded shank 45 in a corresponding threaded part of the flange 42. As a result, even if the bolts 41 are withdrawn, the adaptor ring 43 cannot be removed other than by a machining operation such as drilling. The arrangement described, therefore prevents removal of the cap assembly 124 and adaptor and its replacement with a standard check valve and poppet, while enabling the modified elbow to be used to test the fuel line between the tank and the pump.

With sealing plug 26 in place, the suction line between the angle valve and the pump can be tested through an access port (not shown) in the cap 124, or at an access paint in the underpump valve.

Referring to Figures 4A and 4B, these show a modification of the angle valves shown in Figures 3 to 3G, which can be operated remotely. The valve body 120 may be the valve body of an existing check valve as in the previous embodiment, but in the case of the embodiment of Figures 4A and 4B, the test plug is permanently retained within the valve body. Cap assembly 124 has a central bore in which the plunger stud 30 is received, the plunger being biassed by spring 34 towards the flange 32 which constitutes a valve seat. Plunger 30 is held in its open position by a lever 140 to which it is pivotably attached at its upper end at 141.

11 Lever arm 140 has a rounded portion 142 in contact with the upper surface of the cap 124, the arrangement being such that by lifting the lever 140, e.g. with hook through hole 143, the lever will pivot upwardly and allow the plunger to close down onto seat 32 in a cam or togglelike action. As shown ir. Figure 4A, the cap includes a tapped hole 144, which constitutes the access point for connection to the pressure testing device by screwing a suitable coupling into the hole. This tapped hole may be sealed with a plug so that, in the alternative, access to the suction line for testing can be made at the underpump valve.

Where an existing check valve body is employed, it may be desirable to employ an adaptor flange and tw--st-of--f bolts as described in connection with Figure 3G.

The underpump valve 6 is shown in detail in Figures 5 and 5A. The underpump valve comprises a valve body 61 having a central bore, providing a valve seat 62. A poppet valve 63 is mounted within the bore and is biassed into a closed position by spring 64. In normal operation, suction applied by the petrol pump in the direction of the "flow" arrow raises the poppet against the action of the spring 64. Valve body 61 incorporates a valve lifter 65, which consists of a shaft rotatably received in the body 61 and having a forward end which projects beneath the poppet 63. The forward end of the 111- shaft may be fitted with a pin at right angles to the shaft so that in a first position, it is inoperative and in a second position the pin lifts the poppet 63 off its seat against the action of the spring 64. In such second position, the suction line is then free to drain back into the tank. If necessary,-in-order to break any vacuum a port 66, which communicates with a chamber 67 beneath the valve 63, is opened.

The which is valve body 61 also includes a valve closer used to shut off the supply line to the tank 68 for testing purposes. Closer 68 comprises a rotatable spigot 69 on which a cylindrical closure member 70 is concentrically mounted. Thus, by turning the spigot into the position shown in Figure 5A, valve 63 is shut off the suction line isolated from the pump. Testing of suction line for integrity can then be made through port 66, which may incorporate a sealing cap which removable for connection to the portable testing device As shown in Figure 5A, the centre of the poppet 63 has a raised, circular central portion 71. This ensures that when the cylindrical closure member 70 is rotated into contact with the poppet, a closure force is exerted on the poppet which is accurately aligned with the axis of the valve. This ensures secure sealing of the valve. The necessary closure force can be applied using a screwdriver blade engageable with a slot 72 in the spigot and the the is t3 69. It may be more convenient to arrange for the valve closer 68, the valve lifter 65 and the test point connection or coupling 66 to be on the same face 73 of the underpump valve. Also, in order to prevent the valve closer being operated during the normal use of the pump, the head of the closer 68-may be-shrouded with a sleeve having a c ut-out which engages with a sealing cap -for the coupling 66. This effectivelv locks the closer 68 until the sealing cap is removed from the coupling 66.

As indicated above, the vent pipe or pi-pes from the tank preferably incorporate a shut-off valve mounted above ground level. The shut-off valve incorporates or is in conjunction with a sealable access point to the used vent line. This enables the pressure testing dev.Jce to be connected to a vent pipe for testing the integrity of the tank. One example of a suitable form of construction of a shut-off valve incorporating a test access point is shown in Figures 6 and 6A.

Referring to these drawings, a shut-off valve comprises a valve body 81, arranged to be mounted in the vent pipe so that the arrow X indicates the top of the vent pipe. Valve body 81 incorporates a valve seat 82. A valve poppet 83 is mounted eccentrically on a hollow shaft 84 so that on rotation, the valve is movable towards or away from the valve seat 82. Because of eccentric movement of the shaft, the valve incorporates a wiping 14 action which cleans the valve seat as it closes. For this reason, the washer 87 may be dome shaped. Shaft 84 includes a passage 85 which is connected externally with a self-sealing coupling 86 and internally with the valve body upstream of the valve seat. Thus, in the closing position in the valve, the testing apparatus can be connected to the coupling 86 by removing the sealing cap 88 and the integrity of the tank pressure- tested.

When testing the tank, the inlet port 121 of the suction line is first plugged and/or the poppet 6_3 3 of the underpump valve closed. If the inlet port 121 is plugged using a spnng biased test pluo, the rating of the spring 34 (see Figure 33 etc.) in the elbow can be selected to lift at a predetermined pressure in order to provide a safety relief valve and thus prevent an excessively high testing pressure being inadvertently applied to the tank.

Claims (11)

CLAIMS:-

1. An elbow connector for connecting a fuel tank to a suction line servin a fuel dispensing pump and for use in pressure testing the suction line, said 9 connector comprising a body having an inlet port for connection to a feed conduit from the tank, a supply port for connection to the suction line, an access port and a plug which can be introduced through the access port and which is movable under the action of a spring to close the inlet port and enable the suction line to be pressure tested.

2. A connector as claimed in claim 1 in which the plug includes a cap for closing said access port and a testing port is provided in the cap through which the suction line can be pressure tested.

A connector as claimed in claim 2 in which the plug includes a rod attached to a plunger and the rod is dimensioned to extend through the testing pert in the cap.

4. A connector as claimed in any one of the preceding claims in which the spring is selected to allow the plug to lift in the event that an excessively high testing pressure is applied to the suction line.

5. A connector according to any one of the preceding claims which includes a conical filter located in the region of the inlet port so that the apex of the cone extends into the inlet port.

6. An elbow connector for connecting a fuel tank. to a suction line serving a fuel dispensing pump and for use in pressure testin the suction line, said 9 connector comprising a body having an inlet port for connection to a feed conduit 1C7 W from the fuel tank, a supply port for connection to the suction line, an access port which is normally closed with a cap and a plug for temporarily closing the inlet 16 port while conducting a pressure test on the suction line, said plug comprising a plunger for closing the inlet port and a supporting rod which extends through the cap and is pivotally connected to an operating lever to open and close the inlet port.

7. A connector as claimed in claim 6 wherein a spring is positioned to urge the plunger into closing engagement with the irdet port.

8. A connector as claimed in claim 7 wherein the spring is selected to allow the plunger to lift in the event that an excessively high testing pressure is c - Z:1 applied to the suction line.

9. A connector as claimed in claim 7 or 8 wherein pivoting of the operating lever in one direction causes the plunger to be closed onto the inlet port and pivoting in the other direction causes the plunger to be raised off the inlet port.

10. A connector as claim A in claim 9 wherein a testing port is provided in the cap.

11. A connector as claimed in any one of the preceding claims wherein the cap is spaced from the body by an adaptor ring, said ring preventing a standard check valve being fitted to the valve body.