GB2131559A - Indicating contents of liquefied gas vessels - Google Patents

Abstract

A device for providing a continuous visual indication of the contents of domestically used liquefied fuel gas containers or bottles is inserted under the edge of the bottle 1 and comprises a flat hairpin spring 3 the ends of which are folded and pierced with apertures to house a magnifying and indicating mechanism. The spring is provided with projections 9, 15 which closely define the points of engagement of the bottle and supporting surface. The indicator consists of a roundel 6 which rises fully from a slit in the mechanism emplacement when the bottle is full and gradually sinks back therein as the bottle is emptied. The roundel may be provided with markings to show when significant fractional amounts of gas have been consumed. <IMAGE>

Description

SPECIFICATION Device for indicating contents of liquefied gas containing vessels The invention relates to a method of constructing a measuring means for continuously indicating the quantity of liquefied fuel gas present in pressure-resistant containers or bottles.

Fuel gases such as butane and propane are in abundant use as an energy source for domestic purposes, being liquefied at modest pressure for storage in metal containers. A popular size of storage vessel for a 1 5 kilogramme charge of liquefied gas has a total gross weight of over 30 kilogrammes and it is no easy matter to determine what quantity remains in the container by, for instance, lifting and shaking.

The invention comprises an upwardly urging spring means inserted under one side of the gas containing vessel cooperating with a built in measuring device which continuousiy indicates the deformation of the spring means between the points at which the vessel is full and empty, thus providing a visual indication of the contents of the vessel.

In the drawings accompanying this specification; Fig 1 is a side elevation of a gas bottle of commonly used proportions resting on a flat surface at one side and upon the indicating device at the other; Fig 2 is a plan view complementary to Fig 1; Fig 3 is a perspective view of the upwardly urging spring means; Fig 4 is a view showing an alternative method of construction; Fig 5 shows an extension piece which may be used with the spring means; Fig 6 is a perspective view of the lower side of the spring means showing additional features; Fig 7 is a perspective view of the parts used in a preferred indicating device; Fig 8 shows how the moving parts of the indicating device operate; Fig 9 shows how the emplacement parts locating the indicating mechanism fit into an aperture in the spring means.

In these drawings, like numerals refer to like parts.

Fig 1 shows a container 1 resting on a flat surface 2 at one side, spring means 3, hereinafter referred to as spring 3, being interposed between the container and the supporting surface at the other side. The part cross-sectional view of the container shows a commonly used method of construction, there being a curied annular ring welded to the bottom of the container; some vessels have a vertically straight lower support ring. An indicator 6 rises fully from an emplacement carried by spring 3 when the container is full and collapses back therein when the container is empty. Spring 3 is provided with three projections 1 5 which are described later.

Fig 2 shows a plan view of container 1 resting on spring 3, the outer dashed circular line representing the periphery of the container which closely engages a shallow vee-shaped notch 7.

The inner dashed circular line shows the positions at which the curled annular ring of the container base makes contact with the two raised projections 9 on spring 3. The points at which the load due to the weight of the container is transferred to the device are, therefore, precisely defined and the vessel itself is supported at three definite points, one of them being the supporting surface 2 opposite to the measuring device.

Fig 3 is a view of a preferred form of spring 3, being folded from a single sheet of metal into a slim hairpin shape, the lower member being folded and pierced to accept a mechanism emplacement 4 which is described later. The upper member of the hairpin-shaped arrangement is folded and pierced with an aperture 8, its upper surface engaging an actuating pin 5 for operating the indicating device. The upper edge of aperture 8 is at an angle to the horizontal and the emplacement 4 is made to be stiffly slidable in the direction of arrows 1 0. Therefore, by sliding emplacement 4, it is possible to adjust the position at which aperture 8 engages pin 5 during its downward descent under the influence of the weight of the container.

This artifice is used to set the zero point of the indicating device when the container 1 is empty. A preferred form of indicator 6 is shown in dashed lines in the position it reaches when the container is fully charged. The two raised elongate projections 9 which sustain the weight of the container vessel are also shown.

Fig 4 shows an alternative method of constructing spring 3 using two parts which are united by spot-welds 11.

Fig 5 is a further view of a part of spring 3 showing the rectangular aperture 12 into which mechanism emplacement 4 is fitted. An additional component 1 3 is also shown. This is a recessed notch-piece made in a plastics material which may be slid over the existing notched edge of spring 3 in the direction of arrows 14. This may be used to alter the point of engagement of the gas container with the device, particularly containers having vertically straight support rings as the force conditions are then different.

Fig 6 shows the lower face of spring 3 provided with three projections 1 5 which have been previously mentioned as engaging the supporting surface 2. These projections ensure that the reaction from the supporting surface is transferred to the device at three definite points, provided that the roughness of the supporting surface does not exceed the height of the projections. This feature is also of importance when the gas containers are used in certain portable appliances in which the supporting surface may have some degree of flexibility, this rendering the mode of engagement indefinite and causing false readings at the indicating device.

Fig 7 gives perspective views of the parts of a suitable indicating mechanism. Although a considerable number of types of indicating device may be used with the basic spring 3, the preferred mechanism only is shown. This employs a circular indicator or roundel 6 which rises fully from emplacement 4 when the gas container is full and falls to the point at which its upper edge just disappears within the emplacement when the container is empty. It is not then vulnerable to damage when not in use or during transportation.

This type of indicator, when made in a distinctive colour, such as yellow, enables a remarkably accurate visual estimate of the gas container contents to be made even if carries no markings. It may, however, be provided with distinctive markings such as lines or dots to show when significant gas charge levels have been reached, such as at the quarter, half and threequarter levels.

Alternativeiy, it may be provided with an annular ring of vivid colour affixed to the outer face of the roundel, some important level such as one tenth full charge being indicated when the inner edge of the annulus is on the point of disappearing into the emplacement.

Accordingly, roundel lever 6 is pivotally mounted on a pin 1 6 projecting from an emplacement piece 1 7 which, when brought into engagement with complementary emplacement piece 1 8 forms the emplacement 4 referred to hereinbefore. Part 1 7 is furnished with two projecting pins 1 9 and 20 which serve as an anchorage for wire spring 21 shown in its fully bent position when engaged below previously mentioned actuating pin 5, which is made integral with primary lever 22, tending to urge this lever upward when its boss 23 is pivotally mounted on pin 19.Part 1 8 also carries a spacing pad 24 to allow for the thickness of the spring 21 and is further provided with a central aperture 25 through which pin 5 extends backwards to engage aperture 8 in spring 3. Lever 22 is furnished with a pin 26 capable of engaging slot 27 in roundel lever 6 when the mechanism is assembled. When the emplacement parts 17 and 18 are brought together with projections 28 above and touching 18, a central slot is formed through which lever 6 may rise in the direction of arrow 29 when primary lever 22 moves downwards in the direction of arrow 30 as a result of pressure exerted on pin 5 by spring 3, spring 21 causing the reverse action when the pressure is removed.When the parts are fitted into the emplacement aperture 1 2 in spring 3 they remain relatively slidable in the direction of arrows 31, permitting adjustment of the magnification ratio of the lever combination 6 and 22 owing to the induce alteration of the point of engagement of pin 26 with slot 27. Such an adjustment means is necessary to allow for variations in the elastic properties of spring 3 and also to permit the same mechanism to be used with gas containers of differing manufacture, their lower edge arrangements sometimes engaging spring 3 at a different position.

After assembly, part 1 8 is adjusted by lateral sliding until the indicator lever 6 is just beginning to emerge from emplacement 4 when the device is loaded by an empty container. Part 17 is then also adjusted by sliding it relative to 1 8 until the roundel has fully emerged from the emplacement when the device is loaded with a fully charged container.

The parts 17 and 18 are then firmly united by, for instance, sonic welding of the projections 28 to the emplacement piece 1 8. The zero position of lever 6 may then be adjusted by the user by sliding the entire assembly in its mounting aperture 12 in a manner previously described, permitting variations to be made to allow for differing total empty weights of the container and any attachments used.

Fig 8 is a frontal elevation showing more clearly how the levers 22 and 6 cooperate to produce the desired result, the roundel being drawn in the empty position, the dashed line being the point to which it rises relative to emplacement 4 when the container is full. This mechanism may be used to provide a linear magnification ratio of the centre of the roundel relative to actuating pin 5 of up to 12:1, which is a necessity if spring 3 is to be kept slim enough to slip under the container easily. With the construction as described, the total thickness of spring 3 with its load sustaining projections need not exteed 10 mm., the working range of the spring being of the order of 3 mm.

The proportions are chosen so that the spring must descend through a small safety distance before actuating pin 5 becomes engaged and also so that there is a small reserve between the full container position and the position at which the members of the hairpin type spring 3 come into contact under additional downward pressure.

Allowance is also made so that lever 6 may rise past the full position without damage if such additional pressure be exerted, as my occur when the device is being placed under the container.

Fig 9 is a cross-sectional side elevation of emplacement members 17 and 18 through a central plane in the direction of arrows 32 in Fig 8, showing how they fit into aperture 12 in spring 3.

In this view is shown a groove 33 in part 1 8 which is not visible in Fig 7. This groove closely fits the edge of the aperture 12 in spring 3 and serves to provide a directionally rigid connection between the two parts. After assembly and adjustment of the lever magnification ratio as previously described, the two projections 28 on emplacement part 1 7 may be sealed to the upper face of emplacement part 1 8 by sonic welding in the direction of arrow 34. Alternatively, the two parts may be provided with fine serrations at the interface perpendicular to the direction of relative sliding, it then being necessary to furnish lugs at the ends of part 1 7 to engage the lower face of spring 3 at the ends of aperture 12 to prevent the upward escape of the emplacement part 1 7. The two parts then remain adjustable by the application of a lateral force which is appreciable in relation to that required for adjusting the zero point of the indicating mechanism, the alteration of the magnification ratio remaining possible subsequent to manufacture. The length of groove 33 and general proportions of the two emplacement parts are chosen that there is sufficient lengthwise clearance in aperture 12 to enable the adjustments mentioned to be made over any foreseeable range.

Using the construction described, the device operates very smoothly over the required range, there being no stick-slip effect owing to the absence of frictional effects in the heavily loaded spring 3, as may occur in devices utilising pivots.

This is a matter of importance if the user is to be inspired with confidence in the readings given by the device because it must be able to detect weight changes which are small in relation to the total weight of the fully charged container.

Claims (18)

1. A device for providing a continuous indication of the contents of an axially vertical cylindrical liquefied gas container when placed between a point on the lower edge of the circular periphery of said container and a supporting surface, the diametrically opposite edge of the container periphery resting directly on said supporting surface and comprising an upwardly urging spring means which resists the gravitationally induced downward thrust of the container, the deformation suffered by the spring means being utilised to influence an attached motion magnifying and indicating means.

2. A device as in Claim 1 in which the spring means consists of a rectangular sheet of metal folded perpendicularly to its major length over a forming means of small radius to provide upper and lower flat spring members which are at a small acute angle to each other, the folded portion being inserted under the container periphery towards the central axis of the container and the container load being sustained remotely therefrom.

3. Spring means as in Claims 1 and 2, in which the lower member is appreciably longer then the upper member, the free ends of both being bent vertically upwards a short distance apart, the lower member then being further bent at a right angle back towards the original fold to cover and extend backwards past the vertically upstanding free end of the upper member, a small compartment for housing an indicator mechanism being so created.

4. Spring means as in all preceding claims in which the upper horizontal surface of the lower member is pierced with an aperture above the mechanism compartment for securing a mechanism assembly and in which the vertically upstanding free end of the upper member is pierced with a centrally disposed motion transmitting aperture, the upper edge of which is at an angle to the horizontal.

5. Spring means as in all preceding claims in which the upper member is provided with two upwardly formed gas container load sustaining projections of elongate shape adjacent and parallel to its free edges and closely approaching the mechanism compartment.

6. Spring means as in all preceding claims in which the lower member is provided with three downwardly formed reaction sustaining projections one of which is centrally disposed and adjacent the original fold, the other two being adjacent the free edges and more remote from the fold than the container load sustaining region.

7. Spring means as in all preceding claims in which the backwardly projecting free end of the lower member is notched to provide a gas container engaging and locating projection at each side of said free end.

8. Motion magnifying and indicating means for a device as in Claim 1 for attachment to a spring means as prepared according to all subsequent claims comprising a primary lever which is pivotally mounted at one side of the mechanism compartment, cooperating with a secondary indicating lever pivotally mounted at the opposite side of said compartment.

9. A two lever mechanism as in Claim 8 in which the primary lever carries a centrally disposed backwardly projecting integral pin which is engaged by a motion transmitting aperture as in Claim 4, the end of the lever remote from its pivotal mounting carrying an integral forwardly projecting pin which engages a slot in the secondary lever which is formed radially from the pivot hole of the latter and terminates close thereto.

10. A mechanism as in Claims 8 and 9 in which the free end of the secondary lever is provided with a disc or roundel, the mechanism proportions being chosen so that the disc rises fully from the mechanism compartment when the spring means is sustaining the load from a fully charged gas container, collapsing back into the compartment when the container is empty.

11. A mechanism as in Claim 8,9 and 10 in which the visible outer surface of the indicator disc is provided with distinctive markings which show when predetermined gas container charge levels have been reached when said markings coincide with the upper face of a slot in the mechanism emplacement into which the disc subsides as the gas charge becomes exhausted.

1 2. An emplacement for an indicating mechanism as in Claims 8 and 9 for assembly into an aperture as in Claim 4 comprising two parts which define a slot for the indicator lever when brought together, the rearward emplacement part having an integral pivot pin for the primary lever and central aperture to accommodate the centrally disposed backwardly projecting motion accepting pin of the primary lever and the forward emplacement part having an integral pivot pin for the secondary indicator lever, the two parts remaining relatively slidable in the assembly aperture.

13. A mechanism emplacement as in Claim 12 in which the rearward emplacement part is further provided with a second integral pin adjacent the primary lever pivot pin, the two pins forming an anchorage for a wire spring which engages and urges upwards the motion accepting pin on the primary lever.

14. A mechanism emplacement as in Claim 12 in which one or other of the emplacement parts is provided with projections which are sealable to the other.

15. A mechanism emplacement as in Claim 12 in which the two emplacement parts are provided, at an interface, with cooperating serrations perpendicular to the direction of relative sliding.

1 6. A mechanism emplacement as in Claim 12 in which the combined assembly of the two emplacement parts remains slidable in the assembly aperture, one or other of the parts being provided with a groove to engage closely around the metal at one side of the assembly aperture in the spring means.

17. A moulded extension piece to alter the position of gas container engagement, one edge being recessed to slip stiffly over the existing notched end of the spring means prepared as in Claim 7, the opposite edge being formed into a gas container locating notch, also as in Claim 7.

18. A liquefied gas container indicating device as in all preceding claims constructed in accordance with the drawings accompanying this specification.