WO1998028568A1

WO1998028568A1 - Integrated filling, dispensing and contents indication unit for liquefied gas tank

Info

Publication number: WO1998028568A1
Application number: PCT/AU1997/000883
Authority: WO
Inventors: Gerald Louis De Comarmond; Russell John Mcaliece
Original assignee: Stm Auto Gas Tanks Pty. Ltd.
Priority date: 1996-12-23
Filing date: 1997-12-23
Publication date: 1998-07-02
Also published as: EP0963530A1; AU7874598A; AUPO437096A0; EP0963530A4

Abstract

Apparatus is disclosed forming part of a liquefied gas tank, in which are integrated means to control replenishment of the contents of said tank (2, 3), means to automatically terminate replenishment flow at a designed percentage of total tank contents, means to control dispensing of the contents from said tank (4, 12, 21), means to generate an indication of the contents of said tank (13), and means to protect said tank against excessive internal pressure (20), said integrated means being all incorporated into or attached to a single, compact block (1).

Description

INTEGRATED FILLING, DISPENSING AND CONTENTS INDICATION UNIT FOR LIQUEFIED GAS TANK

This invention relates to the provisions in liquefied gas tanks, to replenish their contents, to dispense liquefied gas from them, to provide contents indication in them and to safeguard them against excessive pressures.

More particularly, the invention relates to such provisions in tanks for automotive applications and intended to contain liquefied petroleum gas fuels such as propane, butane and the like.

In a tank for the storage of liquefied petroleum gas in automotive applications, it is usual to mount discrete means for replenishing its contents, for dispensing of gas from it, for indicating its contents and for excessive pressure relief, on a robust plate of suitable size which is then bolted over an opening in the shell of the tank. It is usual for said provisions to incorporate automatic cut-off means which act to terminate filling at approximately 80% of total tank volume and a manual cut-off valve for emergency use. Similarly, dispensing provisions usually incorporate a remotely controllable cut-off valve in the form of a electrically operated solenoid valve and a manual cut-off valve for emergency use. Excessive pressure relief is provided by a valve held against a seat by spring pressure in the form well known in the art .

The incorporation of discrete means for each of the said functions necessitates the use of a mounting plate of relatively large dimensions which, in turn, necessitates the provision of a commensu- rately large opening in the tank shell. Such an opening acts to reduce the strength of the tank and, as a result, its edges must be suitably reinforced and a relatively large number of fastenings used to fix the mounting plate to the tank shell in a manner able to safely sustain the stresses imposed upon it by the pressure of the contents of the tank. Further, the provision of the said mounting plate and discrete means for each of the said functions, together with the mounting fastenings and sealing provisions is relatively expensive, and the attachment of said mounting plate to the tank shell is inconvenient and requires an excessive expenditure of time. The object of the present invention is to provide a compact, integrated unit which incorporates means to perform all of the functions necessary for the proper use of a liquefied gas tank, which is more easily and more economically manufactured, and which may be conveniently mounted to a small opening in a tank shell.

According to the present invention, an integrated unit is made comprising a single compact mounting block into which are incorporated bosses or housings for the attachment or mounting of filling means with manual shut-off valve; dispensing means with remotely controllable electrical cut-off valve and manual cut-off valve; pressure relief means; and contents indication means which also act to terminate filling at a designed percentage of total tank contents. Said integrated unit is fixed by a small number of fastenings to a mounting reinforce- ment of complementary size and shape welded to the tank shell. Said mounting reinforcement optionally incorporates a shroud which substantially encloses said mounting block when it is installed on said mounting reinforcement, said shroud being sealingly closeable by a means of a cover, such that any leakage or discharge of gas into the interior of said closed shroud is conducted to atmosphere through a venting conduit connected to the wall of said shroud. The various aspects of the present invention will be more readily understood by reference to the following description of preferred embodiments given in relation to the accompanying drawings in which:

Figure 1 is a view of the inner face of said mounting plate;

Figure 2 is a view of the outer face of said mounting plate;

Figure 3 is a view of the left hand side of said mounting plate as presented in Figure 2;

Figure 4 is a cross-sectional view of the mounting and shrouding provisions for said integrated unit;

Figure 5 is a longitudinal cross-sectional view of the contents indication and filling

80% automatic cut-off provisions for said integrated unit. With reference to Figures 1, 2 and 3, a compact, integrated unit providing filling, dispensing, contents indication, excessive pressure relief and automatic cut-off at a designed percentage of total tank capacity during filling is made comprising mounting block 1, on the outer face of which are formed filling boss 18, filling manual shut-off valve boss 3, dispensing manual shut-off valve boss 4, solenoid shut-off valve mounting boss 8, dispensing conduit attachment boss 9, dispensing gallery plugging boss 5 and pressure relief venting boss

20. Excepting the filling boss, dispensing gallery plugging boss and pressure relief venting boss, each of said bosses is provided with a threaded recess as depicted generally as 31 in Figure 3. Formed around the periphery of said mounting block body part is mounting flange 6 in which is provided a plurality of holes 7 to accommodate attachment fastenings (not shown) . Preferably, said mounting block is made more or less round but, in alternative embodiments, other regular and irregular shapes might be employed. Elbow fitting 2 is made with a neck (not shown) which is accommodated in a bore (not shown) formed in filling boss 18, said neck being provided with a plurality of circumferential grooves (not shown), the inner ones of which accommodate 'O' ring seals which act to seal said neck to said bore whilst permitting rotational positioning of said elbow fitting, and the outer one of which accommodates two retaining pins 19 which pass through said filling boss from outer face to inner face and act to secure said elbow fitting in place against axial movement whilst permitting its rotational positioning. Also provided in the exterior face of said mounting block is recess 13 to accommodate a tank contents sender unit (not shown) . Formed on the interior face of said mounting block is spigot ring 25 made concentric with inner multiple mounting boss 26, annular groove 30 being provided between the two features to accommodate sealing means (not shown) to seal said mounting block to mounting - reinforcement (depicted as 34 in Figure 4) incorporated into said tank. Formed on the face of inner multiple mounting boss 26 is standpipe attachment boss 24. Provided in said inner multiple mounting boss is a threaded recess to screwably accommodate pressure relief valve 29 and a plain recess 14 to accommodate the bobbin 39 of the tank contents indication and automatic cut-off during replenishment means as depicted in Figure 5. Provided around recess 14 is tank contents indication mechanism attachment face 27, in which are provided threaded holes 17 to accommodate fastenings for the attachment of said tank contents indication means. Stepped annular recess 15 is provided around the opening of recess 14 to accommodate sealing provisions to seal said tank contents indication provisions to said inner multiple mounting boss. The depths of recesses 13 and 14 are made such that the thickness of material between their opposing inner ends is just sufficient to safely sustain, with appropriate margins, the maximum pressures imposed upon it, and is magnetically permeable.

With reference to Figure 4, mounting reinforcement 34 is welded into tank shell 33. Shroud 37 of appropriate size and shape is sealingly attached to said mounting reinforcement and formed around the opening of said shroud is flange 65 to which may be sealingly attached a closure plate (not shown) by means of a gasket or sealing ring (not shown) and a plurality of fastenings (not shown). The walls of said shroud are optionally provided with one or more reinforced panels through which filling and decanting conduits and electrical leads sealingly pass. Venting conduit 38 connects the interior of said shroud to atmosphere and safely conducts away any gas discharged into the interior of said shroud. With reference to Figures 5 and 6, tank contents indication and automatic shut-off during replenishment means are provided comprising mounting flange 43, bobbin 39, bobbin shaft 41, deflector plate 46, support tube 45, pinion and quadrant mounting boss 47, 48, parallel quadrant support arms 50, quadrant 53, pinion 49, quadrant pivot 51, float arm attachment boss 54, float arm 55 and float 56. The clearance between bobbin shaft 41 and the bores 62 of mounting flange 43, support tube 45 and pinion and quadrant mounting boss 47 is such as to provide a suitable bearing for the rotational support of said bobbin shaft. Said pinion is made sufficiently long to permit suitable axial movement of said bobbin and bobbin shaft without it disengaging from the teeth 53 of quadrant 52. Stops (not shown) are formed on the outer face of quadrant 52 and contact quadrant support arm 50 at extremes of travel of float 56. A light coil spring, the restoring spring (not shown), is provided on bobbin shaft 41 between bobbin 39 and mounting flange 43 to urge said bobbin away from sealing ring 58 formed on the outer face of said mounting flange. Preferably, said sealing ring is made from a hard, resilient material, such as Viton, which is resistant to the contents of said tank. Movement of said float and float arm in response to liquid level changes in said tank causes quadrant 52 to rotate about pivot 51, thereby causing pinion 49, bobbin shaft 41 and bobbin 39 to rotate. The arrangement of said tank contents indication mechanism is such as to permit its ready adaption to tanks of various capacities by changing quadrant 52 to one of a different radius and relocating quadrant pivot 51 in a different position along the length of quadrant support arms 50. A further adjustment to said mechanism is optionally made by changing the length of float arm 55.

In operation, replenishment equipment is connected to an external filling point, from which liquefied gas passes through a suitable filling conduit to elbow fitting 2. Said filling conduit passes sealingly through the wall of shroud 37. From said elbow fitting, said flow of liquefied gas passes via a drilling from the lower part of said threaded recess of filling boss 18 to the lower part of said threaded recess formed in filling manual shut-off valve boss 3, to which is screwably attached a manual shut-off valve (not shown). Said manual shut-off valve is operated as required to close off the filling circuit . From said manual shutoff valve, when it is open, said flow of liquefied gas passes via drilling 16 to recess 14. Bobbin 39 of said tank contents indication and automatic cut-off during 9 replenishment means are accommodated within recess 14 with sufficient annular clearance to allow said flow of liquefied gas to pass around it and thence flow via arcuate opening 61 in mounting flange 43 to the interior of said tank. Said flow of liquefied gas is deflected from direct contact with said tank contents indication means by contact with deflector plate 46. Mounting flange 43 is fixed to attachment face 27 by fastenings (not shown) passing through holes 44 in lugs 59 of said mounting flange and screwed into threaded holes 17. Said mounting flange is sealed to said attachment face by the periphery of sealing ring 58 being crushingly accommodated in stepped annular recess 15. Pressure of said inflowing liquefied gas acting upon the inner end of bobbin 39 acts to urge said bobbin inwards towards said mounting flange, but said bobbin is restrained from axial movement by blocking pin 42 in its inner face abutting the face of said mounting flange. While its axial movement is blocked by said blocking pin, said bobbin is free to rotate and the sweep of said blocking pin against the face of said mounting flange is depicted in broken line as 60 in Figure 6. At the point where said tank has been filled to the designed percentage of its maximum contents, rotation of said bobbin has positioned blocking pin 42 coincident with indexing hole 57 drilled in said mounting flange and said blocking pin is free to enter said indexing hole and thereby ceases to block axial movement of said bobbin. Under the urging of the stream of inflowing liquefied gas, said bobbin is axial ly displaced inwardly against the urging of said restoring spring beneath it and raised edge 64 on its inner face is brought into contact with sealing ring 58, thereby interrupting the inwardly flowing stream of liquefied gas. When filling pressure has been withdrawn, by the disconnection of the replenishment supply from said filling conduit, a small bleed passing from end to end of said bobbin (not shown) allows pressure across sealing ring 58 to equalise, thereby permitting bobbin 39 to be displaced axial ly by the urging of said restoring spring and, when blocking pin 42 has disengaged from indexing hole 57, to be free to rotate under the influence of the movement of float 56, float arm 55, quadrant 52, pinion 49 and pinion shaft 41. As said bobbin rotates, the magnetic flux from bar magnet 40 in bobbin 39 passes through the floor of recess 14 and into recess 13, where it acts to move the armature of a sending unit, thereby generating an electrical signal to drive remotely located tank contents indication means. Electrical leads from said sending unit pass sealingly through the wall of shroud 37. Rotation of said armature may also cause a visual contents indicator incorporated into said sending unit to progress across a scale.

Pressure relief valve 29 is set to unseat and thereby relieve the pressure within said tank whenever it rises above a designed figure. Unseating of said pressure relief valve allows a flow of gas directly out through the bore of pressure relief venting boss 20 into the sealed interior of shroud 37, from whence it is safely vented to atmosphere through venting conduit 38. A standpipe (not shown) extending to the lowest point of said tank is screwably attached to threaded bore 22 of standpipe attachment boss 24. Pressure within said tank forces a flow of liquefied gas through said standpipe and via drilling 23 at the base of threaded bore 22 to the lower part of the threaded bore of dispensing manual shut-off valve boss 4, to which is screwably attached a manual shut- off valve (not shown). Said manual shut-off valve is operated as required to close off the dispensing circuit. Said flow of liquefied gas, when said manual shut-off valve is open, then passes via drilling 11 to the lower part of threaded bore 21 of solenoid shut-off valve mounting boss 8. Screwably attached to said mounting boss is a remotely controllable electrical solenoid shut-off valve (not shown), the valving element of which, when said solenoid valve is unpowered, bears against the raised seat surrounding drilling 10, thereby cutting off the flow of liquefied gas to said drilling. Electrical leads connected to said solenoid valve pass sealingly through the wall of shroud 37. When said solenoid valve is powered, said valving element is withdrawn, permitting said flow of liquefied gas to pass from drilling 11 to drilling 10 and thence via a further drilling, the dispensing gallery (not shown), to the lower part of threaded recess 12 of dispensing conduit attachment boss 9. Said dispensing gallery is drilled through dispensing gallery plugging boss 5, the thickness of which is sufficient to allow the external opening of said dispensing gallery to be closed by means of a suitable plug 28. A dispensing conduit (not shown) is screwably attached to said dispensing conduit attachment boss and conducts a flow of liquefied gas to the operational system served by said tank. Said dispensing conduit passes sealingly through the wall of shroud 37. Said integrated unit is fixed to mounting reinforcement 34 by a plurality of bolts (not shown) passing through holes 7 in mounting flange 6 and screwed into said mounting reinforcement. Spigot ring 25 acts to accurately locate said unit, its circumferential surface abutting shoulder 35. An 'O' ring seal (not shown) positioned in groove 30 is crushingly captured between the surfaces of said groove and sealing face 36 and acts to seal said unit to said mounting reinforcement. The outside diameter of inner multiple mounting boss 26 is made such that clearance exists between it and the bore 63 of said mounting reinforcement.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. Apparatus in unitary form, to be installed in and form part of a liquefied gas tank, in which are integrated means to control replenishment of the contents of said tank, means to automatically terminate replenishment flow at a designed percentage of total tank contents, means to control dispensing of the contents from said tank, means to generate an indication of the contents of said tank, and means to protect said tank against excessive internal pressure.

2. Apparatus according to Claim 1 in which said integrated means are all incorporated into or attached to a single, compact block.

3. Apparatus according to Claim 2 in which provisions for attachment of said single compact block to said tank are made round.

4. Apparatus according to Claim 2 in which provisions for attachment of said single compact block to said tank are made in another regular or irregular shape.

5. Apparatus according to Claim 1 in which said means to control replenishment of said tank comprise positionally adjustable inlet elbow fitting, manual shut-off valve, and means to automatically terminate replenishment flow at a designed percentage of total tank contents, said components being interconnected by internal drillings in said single compact block.

6. Apparatus according to Claim 1 in which said means to automatically terminate replenishment flow at a designed percentage of total tank contents comprise an axial ly displaceable cylindrical bobbin forming part of means to generate an indication of the contents of said tank and past which replenishment flow is directed, said cylindrical bobbin being rotatable by mechanical means connected to a float supported on a pivoting arm inside said tank and being restrained from axial movement at lower contents levels by a blocking pin protruding from it abutting an adjacent face, rotation of said cylindrical bobbin at maximum replenishment level bringing said blocking pin into coincidence with an indexing hole, permitting said cylindrical bobbin to be axially displaced under the influence of said replenishment flow to abut a sealing ring beneath it and close off an inlet opening, thereby terminating said replenishment flow.

7. Apparatus according to Claim 6 in which a small bleed passage is provided passing from end to end through said cylindrical bobbin and which acts to equalise pressure across said sealing ring and said cylindrical bobbin when said replenishment flow is interrupted.

8. Apparatus according to Claim 6 in which a light restoring spring is provided beneath said cylindrical bobbin to displace it from said sealing ring and thereby open said inlet opening when pressure across said sealing ring and said cylindrical bobbin has been equalised.

9. Apparatus according to Claim 1 in which said means to control dispensing of the contents of said tank comprise a standpipe extending to the lowest point of said tank, a manual shut-off valve, a remotely-controllable electrical solenoid shut-off valve fixed to the exterior surface of said single compact block, and a dispensing conduit attachment boss formed on the exterior surface of said single compact block, said components being interconnected by internal drillings in said single compact block.

10. Apparatus according to Claim 9 in which said remotely-controllable electrical solenoid valve closes when power to it is cut off.

11. Apparatus according to Claim 1 in which means to generate an indication of the contents of said tank take the form of a float supported on the end of a pivoting arm inside said tank, the pivot of said arm being supported from the interior surface of said single compact block and said pivoting arm having fixed to it at said pivot a toothed quadrant, pivoting of said arm causing said quadrant to rotate, and thereby a pinion engaged with said quadrant to rotate, rotary motion of said pinion being transmitted by a connecting shaft to cause a cylindrical bobbin to rotate, magnetic flux from a magnet accommodated within said cylindrical bobbin passing out through the closed end of a cylindrical recess in which said cylindrical bobbin is accommodated and acting to rotate the armature of a sending unit fixed to the exterior surface of said single compact block, signals from said sending unit being transmitted by suitable conductors to a remote contents indicator.

12. Apparatus according to Claim 11 in which visual contents indication means are incorporated into said sending unit.

13. Apparatus according to Claim 11 in which said pinion is made sufficiently long so that its teeth remain engaged with those of said quadrant when said cylindrical bobbin and thereby said connecting shaft and said pinion are axially displaced during automatic termination of replenishment flow at a designed percentage of total tank contents.

14. Apparatus according to Claim 1 in which means to protect said tank against excessive internal pressure take the form of a spring-loaded valve attached to or incorporated into the interior surface of said single compact block and displaced from its seat by excessive pressure, said excessive pressure being relieved by a flow of gas passing through said valve and out through internal drillings in said single compact block to vent to atmosphere.

15. Apparatus according to Claims 1, 2, 5, 6 and 9 in which said manual cut-off valves and inlet elbow fitting at accommodated within radially arranged bosses situated around the periphery of said single compact block.

16. Apparatus according to Claims 1, 2, 3 and 4 in which said single compact block is sealingly fixed to a mounting reinforcement of complementary shape and size incorporated into the shell of said tank.

17. Apparatus according to Claim 16 in which said single compact block and said mounting reinforcement are sealingly enclosed in a shroud and cover, the interior of said shroud being vented to atmosphere through a suitable venting conduit.

18. Apparatus according to Claims 6 and 11 in which a deflector plate is provided between said inlet opening and said pivoting arm, toothed quadrant and pinion to deflect said replenishment flow passing through said inlet opening from impingement upon said components.