WO1991000988A1 - Mobile calibrating apparatus for control of volume meters for liquid, especially propellant pumps in the traffic sector - Google Patents

Abstract

The invention relates to a calibration apparatus for control of propellant pumps, especially in the traffic sector, which apparatus is placed on a vehicle, especially a trailer. The apparatus (1) has at least one standard (10) for measuring a determined amount of propellant, and the standard is placed in a cardan suspension (49-52) which is elastically yielding (48) and may be locked during operation and during transport by means of supporting rods (53-59). A standard (10) is divided into a lower measuring compartment (11) and an upper foam top (14) which is connected to the measuring compartment (11) through a neck (12) with a measuring glass (13) and reading lines (22). The foam top (14) is ventilated (35-37) to a reception tank (5) placed at the bottom of the apparatus (1), and the standard (10) may be connected via a remote controlled discharge valve (20) to the reception tank (5) from which propellant may be pumped up into a buffer tank (64) at the top of the apparatus (1). From here the propellant may be returned to the storage tank of the tank station through a hose (72) either by the aid of gravity or by means of a pump. An electric generator (78) which may be driven by a belt drive (79-84) connected to one of the road wheels (2), may charge an accumulator (87), and a pressure container (88, 89) with a non-flammable pressurized gaz, e.g. carbondioxide, is provided for remote control of the discharge valve (20). A control device for time control of the functions of the apparatus is further provided.

Description

MOBILE CALIBRATING APPARATUS FOR CONTROL OF VOLUME METERS FOR LIQUID, ESPECIALLY PROPELLANT PUMPS IN THE TRAFFIC SECTOR.

The invention relates to a calibrating apparatus for con¬ trol of volume meters, especially volume meters for delive¬ ring highly inflammable liquids, f. inst. volume meters in the form of propellant pumps in the traffic sector, which calibrating apparatus has at least one standard designed with a determined volume and provided with a filling ope¬ ning and a discharge opening connected to a reception tank, and in which the standard and the reception tank are placed on a frame provided with wheels, especially a trailer.

A society is, both for judicial and fiscal reasons, inte¬ rested in safeguarding that a citizen while filling propel- lants into a motor vehicle may receive the correct amount in accordance with the desired or ordered amount.

Earlier types of propellant pumps have been known in which the propellant was pumped by hand from a subterranean stor¬ age tank into one or more measuring glasses which each might have contained f. inst. five liters, whereafter the propellant was poured via an adjustable valve through a hose and a filling nozzle down into the tank of the vehicle. It was hereby possible for the citizen or for an inspector appointed for the task to control the correct amount of propellant, as the measuring glass was provided with indicating marks so that the volume might easily be controlled.

However, these types of propellant pumps were slow in ope¬ ration and the manual pumping demanded a great deal of working power,- and the applicability of the propellan pumps therefore declined concurrently with the rising em- ployment of motor vehicles.

Modern propellant pumps therefore are motor driven and are provided with pumps and measuring means which show the amount of propellant delivered.

However, measuring means of this kind may change in accura¬ cy, f. inst. because of wear or impurities, and a citizen normally has no possibility of controlling the amount of propellant delivered, as this is pumped directly into the tank of the vehicle. The possibility available to a citizen to control the amount of propellant delivered would be for he or she to bring along a volume calibrated container, a so called standard, which would be filled up to a certain graduation mark, whereafter the contents of the container would be poured into the tank, f. inst. by lifting the con¬ tainer and pouring the contents through a funnel and a hose.

Considering that a modern private vehicle has a tank of a volume of 40 liters or more, and that a lorry often may have a tank of several hundred liters, such a control would be Utopian to accomplish for the ordinary citizen because the propellant pump would be blocked for a considerable pe- riod.

On the other hand this kind of control has been available for an authorized control of petrol pumps, but it cannot live up to the latest requirements on efficiency, environ- mental care and fire resistance.

It should be remembered that in the authorized control the measured amount of propellant is not bought, so that the propellant collected in the standard is still the property of the owner of the tank, and that the amount of propellant contained in the standard has to be returned to the storage tank of the petrol station through a filling pipe which for reasons of fire prevention is situated at a considerable distance from the propellant pump. The storage tank is nor- mally for the same reasons situated underground and tank stations are provided with several propellant pumps which all have to be controlled.

To achieve the necessary guarantee of a correct verifica- tion or calibration of the individual liquid meter in the propellant pump the control of the liquid pump has to be effected by means of several consecutive fillings and emp¬ tyings of the standards.

Furthermore, the propellant pumps deliver petrol in an amount of typically 60 liters per minute through filling nozzles which are provided with means for automatical stop¬ ping of the pumping if a tank is filled or the propellant during the filling "kicks back", and the calibration of the measuring means of the propellant pump presumes a constant flow from the activation of the filling nozzle to the ter¬ mination of a delivering process. When the propellan leaves the filling nozzle it is mixed with a great deal o air which in connection with the above mentioned rathe high pumping speeds results in the formation of foam in th propellant in the standard. This blending with air may b accompanied with an evaporation as a result of the rela tively high vapour pressure of the propellant.

To oppose a kickback from the propellant and to be abreas of the foam formation the normal standard is provided wit a tall funnel-shaped neck so that the filling nozzle may b kept at a distance above the level which indicates the de termined correct charge of the standard, and the standar has to have a volume which corresponds to the lowest lega sales volume, e. g. five liters, and a comparatively broad sole to be able to stand solidly during the filling.

Two liquid indicating glasses, with markings for reading the liquid volume, are placed in diametrically opposite sides of the funnel-shaped neck. Hereby it is possible to calculate a mean value for the readings so that it is pos¬ sible to compensate for a vertically abberant position of the neck or the longitudinal axis of the standard.

Substantially larger standards are also in existence, e. g. with a volume content of 20 liters.

A filled standard therefore may represent a considerable weight which may be a great disadvantage when it has to be carried from a pump to the filling pipe at the storage tank and when it has to be handled during the emptying.

To ensure uniform conditions during the emptying at several subsequent measurements it is, to counter measuring errors as a result of remnants of propellant left over from pre¬ vious measurements, commom practice to tip the standards and let the propellant flow from the top of the standard till the remnants are leaving the standard drop by drop at intervals of one second, which in practice is based on the time sense of the inspector in question with the resulting inaccuracy of measurement.

The propellant gives off vapours during the filling which partly are unhealthy to inhale and partly represent an ele¬ ment of danger because of their inflammability.

The above descibed method of control of propellant pumps by means of standards therefore represents a rather large a- nual task which furthermore is connected with danger of life and health.

To counter these disadvantages a calibration apparatus is known, f. inst. from Norway, of the kind mentioned in the introduction.

In this apparatus a two-wheeled trailer is employed which at front is provided with a coupling arrangement so that the trailer may be connected to and be drawn by a motor vehicle. Several standards of various sizes from the smal¬ lest to the largest prescribed size are placed on each side of the trailer. Each of the standards has at the bottom a draining opening which through a short, rigid and transpa¬ rent hose and a manually operated valve is connected to a reception tank in the bottom of the trailer. The standards have a tall narrow neck which is provided with windows on two diametrically opposite sides, and which windows have engraved measurings lines. The tall narrow necks ensure in a commonly known way that even a small change in the volume of a liquid poured into the standard will result in a large change in the level of the liquid in the narrow neck. The neck of each of the standards is provided at the top with an open funnel which serves to direct liquid into the neck.

The standards are fixed to the trailer and as the surface at the petrol stations is slanting towards a drain with a rather large downward gradient to promote a quick collec¬ ting of spilled propellant, the standards may not right away be placed with their longitudinal axes in a vertical position which is a condition for the correct reading of the liquid level in relation to the reading lines of the windows. It will therefore be necessary, as when the tradi¬ tional loose or free standards are used, to make readings of the two opposite windows or indicating glasses and c<il- culate a mean value. This is a difficult and time-consuming process .

It is possible to supervise through the transparent hose after the manual opening of the draining valve that the propellant flows from the standard down into the collection tank, but it is not possible to ascertain when a uniform amount of liquid residue is left in the standards.

The open funnels involve a risk of spreading of vapours which implies dangers of fire and explosions and environ¬ mental hazards. Furthermore, the trailer has to be driven to the filling pipe of the subterranean tank so that the propellant may be emptied into the tank which implies unne¬ cessary driving on the premises of the petrol station, as the filling pipe usually is situated far from the propel¬ lant pumps.

It is the object of the invention to describe an embodiment of a calibration apparatus in which the above mentioned double reading and calculation of the mean at every mea¬ surement with a standard is not necessary, the emanation of dangerous vapours is avoided or diminished, the former manual work of returning the measured propellant to the storage tank of a petrol station is replaced with mechani- σal work, and in which the arrangement is such that modern strict requirements will be complied with, and that the ca¬ librating apparatus will be self-supporting with the neces¬ sary energi so that it may be operated independently of ex¬ ternal energy.

This object will be achieved by a calibration apparatus of the kind described in the introduction which apparatus ac¬ cording to the invention is characteristic in that the standard or standards are suspended in a lockable cardan suspension,^'that the connection between the above mentioned discharge opening or each of the discharge openings and the reception tank consists of a flexible discharge hose which is provided with a remote controlled discharge valve, that the standard or each of the standards has a foam top with a cover, which foam top is connected to the reception tank through a ventilation hose, that a buffer tank is placed at the top of the frame and is connected partly to the recep¬ tion tank through a pipeline provided with pumps and partly to a hose which may be rolled out from a hose drum and which is designed to be connected to a filling pipe on a storage tank in a petrol station; that hydraulic or pre¬ ferably pneumatic and electric power means are provided in the frame, together with a control device with means for controlling the said pumps, and power means and a time con- trolled remote-control of the discharge valve or valves; that the frame is divided into three sections by fire-re¬ sistant bulkheads of which the standard section contains the standard or standards, the tank or pump section con¬ tains the reception and buffer tanks, the pumps, the hose drum with the said hose, said power means and an electric generator which is connected to one of the wheels by means of a possibly releaseable driving device, and the electro¬ nics section contains the control device and accumulators for collecting the electric power produced by the generator during transport.

By the calibrating apparatus according to the invention less work demanding execution of the calibration of volum meters in propellant pumps is achieved, and at the sam time as the reduction of the manual work a reduction of th fire hazard and an improvement of the environmental condi tions is achieved.

The cardan suspension of the standard or standards result in a substantial reduction of the measuring work as i contrast to the known techniques, in which it was necessary to make two readings from opposite sides of the standard and a following calculation of a mean of the readings, which was a great and time consuming task, it is now only necessary to undo the locking to bring the standards or a particular standard into a vertical position within a cer¬ tain tolerance, after which this position through locking may be fixed during the measurements at one particular pro¬ pellant pump.

The taking up of the correct position is eased by the emp¬ tying being affected through the above mentioned flexible hose which because of its flexibility does not oppose the said movement into a vertical position.

Through the emptying via a remote controlled discharge valve a possibility is achieved of an automatic time con¬ trol of the emptying of a standard which therefore may be effected by an objectively working device which performs the said emptying in a reproducible way instead of the known way of emptying, which might either be controlled by determining the interval between drops of propellant or by the time sense of the individual operator or by a manual opening and later closing of a manually operated discharge valve.

Emissions of vapours which are dangerous to the environment or represent a hazard of fire or explosions will be reduced to a minimum by the standard or each of the standards being provided wifch a foam top closeable by a cover and connected to the reception tank by a ventilation hose.

The reception tank is placed low down in the calibration apparatus so that gravitation is employed for emptying the standards which are placed at a higher level than the re- ception tank, and one must bear in mind that the filling of a standard only takes a lift of the nozzle of the propel¬ lant pump to the filling opening of the standard, while it is the pump which delivers the necessary energi for the filling.

Furthermore, the arrangement described of the reception tank, the buffer tank, the pump, conduits and hoses means that the return flow of the measured amount of propellant takes place with the least possible expenditure of energy.

The division of the calibrating apparatus into three zones, which are separated by fire resistant bulkheads, guarantees the safety of the operation of the apparatus, as the indi- vidual devices may be placed in a zone which corresponds to the vulnerability of the concerned device towards fire or explosions or its ability to emit sparks which may cause fire and/or explosions.

This safety is further enhanced thereby that all vapours may be drained off by means of ventilation hoses so that the vapours will only escape to the open either during the filling proper of a standard in which the cover on the foam top necessarily has to be moved away, or through a pressure equalizating hose which is provided with a flame filter.

Furthermore, the placing of hydraulic or preferably electric power means in the apparatus means that this may be made independent of an external supply of energy whereby the damage to wires for the supply of external energy by being run over by vehicles is avoided, and that the cali¬ bration apparatus may be put to use in places without any possibility of finding a supply of external energy.

This internal energy may be produced during the driving of the apparatus because the generator, which is a non-spark- producing generator, is coupled to one of the road wheels whereafter the energy is stored in an accumulator in an as such known way, which accumulator preferably is placed in a particular section together with the control device so that the shortest possible wire connections between the two parts are achieved.

The embodiment described in claim 2 of a standard achieves optimal possibilities that a given change of volume of the propellent in the standard results in the greatest possible change of liquid level in the indicating glass so that this change of volume may be clearly read in relation to the reading lines. This shape also ensures that the foam buil- ding is reduced as quickly as possible..

As a result of the cardan suspension, which within a cer¬ tain tolerance guarantees a vertical position of the longi¬ tudinal axis of the standard, it is sufficient to use only one window or indicating glass, while previously known standards have windows or indicating glasses on two oppo¬ site sides.

It is possible by means of the movable and lockable, re- placeable and as such known displacement body to calibrate the standard to the correct volume.

When the standard is suspended in the way described in claim 3 the distribution of weight of a filled standard will support the tendency of the standard to take up a po¬ sition in which its axis is placed in a vertical plane.

The cardan suspension described in claim 4 is robust, but still permits an easy and fast adaptation to the vertical position of the standards which at the same time, as a re- suit of the elastomeric blocks, will be spring suspended during transport of the apparatus.

When the reception tank is designed according to claim 5 the greatest possible accuracy is guaranteed in subsequent fillings of a standard, as the evaporation of propellant in the standard will be subdued by the pressure of the satura¬ ted vapours in the ventilation duct and in the reception tank.

By the means described in claim 6 it will be possible to return the measured amounts of propellant to the storage tank of the tank station by applying the least possible energy consumption.

When the said pipelines and hoses are connected in the way described in claim 7 it is partly ensured that the emptying of the highly placed buffer tank normally is affected only by gravity, and partly that a possible fire in the vicinity of the calibration apparatus will spread to the buffer tank which may contain a considerable amount of propellant.

Claim 8 describes an advantageous way of designing a power mechanism so that energy may be produced during transport of the apparatus.

It is advantageous to produce pneumatic energy in the way described in claim 9 as such pressure containers may be procured on an ordinary commercial basis and a full pres- sure container may be provided quickly in case a pressure vessel is empty.

It is furthermore advantageous, as described in claim 10, to use optical conductors for the transfer of signals be- tween the control panel, control means and detectors as the danger connected with the use of electrical wires for transfer of signals in an environment of propellant gases is hereby avoided. The necessary electronic optical relays may advantageously be placed in the electronic sector.

The calibration apparatus according to the invention will be explained in the following with reference to an embodi¬ ment of a mobile calibration apparatus according to the in¬ vention as shown in the drawings in which;

fig. 1 is a side view of a calibration apparatus accor¬ ding to the invention with certain parts omitted,

fig. 2 is a back view of the same apparatus,

fig. 3 is a top view of the apparatus with certain parts omitted,

fig. 4 is a back view of a standard according to the in- vention,

fig. 5 is a back view of a cardan suspension for the standards,

fig. 6 is a section along the lines VI-VI in fig. 7,

fig. 7 shows the supporting rods for lockable guidance of the standards,

fig. 8 is a back view of the tank and pump section with a standard section omitted,

fig. 9 shows a belt drive between a road wheel and an electricity generator in which only the parts ne- cessary for the understanding are shown. A calibration apparatus 1 according to the invention is in the shape of a vehicle on road wheels 2, preferably a trai¬ ler which may be connected to a hauling vehicle such as a motor car. The trailer may according to requirements be provided with one or more wheel axles 3 with road wheel 2, which wheel axles 3 are mounted on a frame 4 which supports a bottom plate.

A reception tank 5 is placed in the frame 4 between the road wheels 2 which tank has a volume of f. inst. 30 liters and has rather large dimensions in the horizontal plane, but a small vertical extent. The liquid in the reception tank therefore will quickly achieve a large surface so that the left over volume quickly will be filled with saturated vapours for reasons which together with the employment of these saturated vapours will be explained in the following.

Two fire resistant bulkheads 6 are placed on the bottom plate of the frame which bulkheads divide the vehicle 1 in¬ to three separate, distinct sections, a standard section 7, a tank or pump section 8 and an electronics section 9.

Two standards 10 are placed in the standard section, f. inst. a 5 liter and a 20 liter standard.

Each standard 10 has at the bottom a measuring compartment 11, in the middle a neck 12 and at the upper end a foam top 14 which together has the shape of a body of revolution which in the position of use of the standard 10 has a ver¬ tical axis.

The measuring compartment 11 is constructed of two cones 15, 16 with their apexes turned away from each other and u- nited at their bases by a short cylinder 17. The apex 18 of the downwards turned cone 15 has a discharge opening 19 with a discharge valve 20 and the apex 21 of the upwards turned cone 16 is connected to the neck 12 which is a com- paratively long cylindrical neck with a small cross sec¬ tion. The neck 12 has a window or indicating glass 13 with reading lines 22 either on the glass itself or on an adja¬ cent ruler.

The measuring compartment 11 has a volume which in connec¬ tion with the volume of the indicating glass is larger than the final volume of a calibrated standard so that it is possible to adjust the volume of the standard by means of displacement bodies 23.

A circular spirit level 29 is placed on the upper side of the measuring compartment 11 which level may show whether the axis 30 of the body of revolution is placed vertically within a given tolerance.

Temperature detectors 24 may further be placed inside the measuring compartment 11 for control of the temperature in the measuring compartment.

The foam top 14 has substatially the same shape as the mea¬ suring compartment.

The upper side of the foam top 14 has a filling opening 31 to receive the mouth pipe of a filling nozzle during the filling of the standard with propellant. The volume of the foam top 14 is at least of the same size as the measuring compartment 11 and the volume is moreover adapted in such a way that it may contain both the foam formed by the fil¬ ling, which is caused by the admixture of air in the pro- pellant from the filling nozzle, as the part of the propel- lant which cannot pass down to the measuring compartment in time with the pouring. The volume of the foam top 14 is al¬ so adjusted so that the highest level of liquid foam will be below the mouth pipe of the filling nozzle and its va- cuum pipe, whereby it is avoided that the filling nozzle "cuts out" during the process of filling.

It is important to avoid that the filling nozzle "cuts out" as the volume measuring may only be applicable if the flow of propellant is substantially constant from the activation of the filling nozzle and until the greater part of the vo¬ lume of the standard has been filled, whereafter the fil¬ ling may be terminated at a lower velocity of flow until the desired volume has been filled into the standard ac- cording to the reading of the propellant pump.

To avoid sources of error such as evaporation of propellant from the standard 10 the filling opening 31 is closed promptly with a cover 32 which f. inst. may revolve on a bolt 33 and be spring loaded towards the closed position of the cover so that the cover 32 takes up its closed positio when the filling nozzle is removed from the filling openin and no longer blocks the movement of the cover 32. Besides, a ventilation connection 34 is placed at the upper end o the foam top which connection consists of a first vertica length of pipe 35 which via a slanting upwards extendin length of pipe 36 continues into a short downwards exten ding pipe 37 which is connected to the reception tank through a long flexible hose. The vertical and slantin pipes consists of a transparent material, e. g. PVC, s that it may be controlled that liquid foam is not carrie through the ventilation connection and down into the recep tion tank. The flexible hose is not shown in the drawing for the sake of clarity. During the emptying of the standard 10 through the dis¬ charge valve 20 saturated propellant vapours from the vo¬ lume above the propellant in the reception tank will be sucked through the ventilation connection 34, whereafter this connection during succeeding fillings of the standard will be filled with saturated vapours so that evaporation during these succeeding fillings will be minimized.

The emptying of a standard takes place through the dis- charge valve 20 which may be remote controlled through hy¬ draulic or preferably pneumatic means. This operation may be time controlled by electronic means in a control device.

By a time control of this kind a uniform emptying from time to time of a standard 10 is achieved so that the subjective influence of an operator's counting of drops from the last remnants of propellant is avoided.

The connections between the neck 12 and respectively the measuring compartment 11 and the foam top 14 consist of flange connections 25, 26 which permit an easy disassemb¬ ling and assembling of the separate parts of the standard 10 during reparation and inspection.

A ring 27 is inserted in the flange connection 26 between the foam top 14 and the neck 12 which ring has an opening corresponding to the inside diameter of the neck and on the outside at diametrically opposite points has an outwards extending bearing stud 28 with a circular cross section, which two bearing studs 28 has a common axis. The bearing studs are supported in bearings 38, so that the standard 10 may take up a stable position under the influence of gravi¬ ty, and enter into a lockable cardan suspension of the standard. A longitudinally extending side member 39 with a L-shaped cross section is placed on each side at the back of the ca¬ libration apparatus at a distance above the frame and pa¬ rallel herewith, of which member the two flanges are re- spectively vertical and horizontal; the vertical flanges 40 turned downwards and the horizontal flanges 41 pointing to¬ wards each other.

The horizontal flanges 41 are provided with a free hole which accomodates a vertical bolt 42 with a thread which bolts have a hexagonal head 43 so that the bolts may be turned by a key. The bolts 42 are under the horizontal flanges secured by a disk or nut 44 so that the bolts may only be turned in the above mentioned holes and cannot be displaced in the vertical direction.

Only one bolt 42 is shown in each of the said horizontal flanges 41, but two bolts 42 may be employed in each of the horizontal flanges 41.

A short angle bar 45 is placed on the inside of each side member 39 and is slidable in relation to the member. The vertical flange 46 of the angle bar is pointing upwards and the horizontal flange 47 is pointing towards the opposite side of the vehicle.

The horizontal flanges 47 have free holes which accomodate the shafts of the bolts 42.

Blocks 48 of an elastomer such as rubber, foam rubber or similar materials are placed on the upper and under sides of the horizontal flanges 47 of the short angle bars 48. The blocks 48, which also accomodate the bolts 42, are clamped between the flanges 49, 50 of two short bars 51 which have a U-shaped cross section and which are parallel _D

18

to the above mentioned side members and angle bars 45.

Nuts 144 are welded to the under sides of the flanges 49 which nuts accomodate the bolts 42. It will be understood 5 that by turning the bolts 42 on their longitudinal axes it will be possible both to raise and lower the angle bars 45, the short bars 51 and the elastomer blocks 48 depending of the direction of rotation of the bolts 42.

10 The two angle bars 45 are at their ends connected to the ends of two long beams 52 with U-shaped cross sections so that the angle bars 45 and the long beams 52 together form a rectangular frame with a lengthwise extending opening which is slightly wider than the diameter of the ring 27

15 with the bearing stubs 28 on a standard 10.

The flanges of the two long beams 52 have holes which serve as bearings for the bearing stubs 28 of the standards of which normally one contains 5 liter and one 20 liter are 20 provided side by side.

It will be obvious to the man skilled in the art that the bearing stubs may as well be situated on the sides of the long beams 52, which are turned towards each other, and be 25 interacting with diametrically opposite bores in the ring 27 in the flange connection 26 between the foam top 14 and the neck 12* of a standard.

By means of the vertical bolts 42 and the rest of the ar- 30 rangement the necessary posibilities of adjustment are achieved for placing the two long beams 52 level with refe¬ rence to the unequal distribution of weight which is due to the two unequally heavy standards 10.

35 The elastomer blocks 48 take up vibrations both during transport and when the pumps are working and prevents pro¬ pagation of the vibrations to the standards which are empty during transport.

Supporting rods 53-56 are placed in mutually perpendicular directions between the standards 10 and the frame of the calibration apparatus to achieve a locking of the standards 10.

A first 53 and a second supporting rod 54 are at one end connected by a hinge to a brace 59 which extends around the frame, and at their free and mutually crossing ends have a longitudinally extending slit for the accomodation of a screw 57 which extends upwards from a point at the outside of the measuring compartment of one of the standards, cf. fig. 7. A third supporting rod 55 is similarly connected_.by a hinge to the brace 59, and a fourth supporting rod 56 is placed with one end fixedly connected to said standard 10 by means of an additional screw 58. The free and mutually crossing ends of the third and the fourth supporting rods 55, 56 also have a longitudinally extendig slit which acco¬ modate a screw 159 fixed at the outside of the second stan¬ dard 10. The free ends of the supporting bars 53-56 are tightened to the standards by means of wing nuts on the screws.

Before the first filling of the standards the wing nuts are loosened at the supporting rods 53-56 whereafter both stan¬ dards 10 are filled. When both are full the neck of one of the normals is gripped and moved until the bubble in the circular spirit level 29 shows that the standard 10 is ver¬ tical whereafter the wing nut is screwed tight. The proce¬ dure is repeated at the other standard. The liquid level may now be read from +^•*© reading lines on the liquid indi- eating glass 13. Further adjustments of the positions of the standards 10 at the subsequent fillings from the same propellant pump are hereafter unnecessary, as the supporting rods keep the standards in their correct position in the filled condi¬ tion, and the elastomer blocks 48 will counterbalance pos¬ sible movements of the standards during emptying and fil¬ ling.

The connection between the discharge valve 20 and the re¬ ception tank 5 is designed as a flexible connection in the shape of a hose 60 which is corrugated and/or is bent into a U-shape so as not to obstruct the movements of the stan¬ dards 10 during their filling.

To prevent the formation of sparks by discharge of static electricity in the calibration apparatus 1 a ground lead cable 61 with a clamp, which may be clamped to the ground lead of a propellant pump, is placed in the standard sec- tion 7. The ground lead cable 61 is during transport rolled upon a cable drum arranged for this purpose. The cable drum 62 is rotatably supported in the frame and has a spring sy¬ stem or a handle to rotate the drum on its axis by the rol¬ ling out or rolling in of the cable 61.

A buffer tank 64 is placed as high up as possible in the tank and pump section 8 which tank has a rather large vo¬ lume, e. g. 400 liters.

Two detectors are placed in the reception tank 7 at diffe¬ rent heights which detectors may register the level of the propellant. When the upper detector is acted upon a signal is sent to a pump which through a pumping tube may pump propellant up into the buffer tank 64, so that the pumping is carried out until a signal from the lower detector again stops the pumping. The detectors, the pump and the pumping tube are not shown in the drawings for the sake of clarity.

As soon as so much propellant flows down into the reception tank 5 from the emptying of the standards 10 that the upper detector is activated, the propellant will be pumped up in¬ to the buffer tank 64. The pump stops when the lower detec¬ tor in the reception tank no longer registers any liquid.

Furthermore, a ventilation conduit for pressure balancing between the tanks 5, 64 and the open is provided between the the reception tank 5 and the buffer tank 64 and a pres¬ sure balancing conduit is provided from the buffer tank 64 to the open through a flame filter 65.

The hoses and the ventilation, pressure balancing and pum¬ ping conduits consist of materials which are resistant to¬ wards the chemical environment dominated by the common pro- pellants.

The reception tank 5 and the buffer tank 64 consist of a material which will not cause formation of sparks, such as aluminium, and the tanks are for reasons of strength made of a 3 mm thick plate and have been pressure tested at 0,2 bar.

The buffer tank 64 has a sump 66 with a discharge opening 67. The discharge opening 67 is connected to a discharge conduit 68 which at the end is provided with a remote con- trolled shut-off valve 69 and a hose coupling 70 to which a hose 72 may be connected. The hose 72 is rolled upon a hose drum 71 and has a length of f. inst. 50 m. Its free end is designed so that it may be connected to the filling pipe of a storage tank. The hose drum 71 is placed on a tray 73 which may collect any propellant which may drip from the hose 72 and which via a groove in the tray 73 may drain to the road surface.

The discharge opening 67 is further connected to a conduit loop 74 the other end of which is connected to the dis¬ charge conduit 68 at a Y-shaped connecting point 75 between the discharge opening 67 and the shut-off valve 69. A pump 76 is inserted in the conduit loop 74 which pump may pump propellant from the discharge opening 67 through the shut- off valve 69, the hose coupling 70 and the above mentioned hose 72 into the storage tank.

Furthermore, a non-return valve 77 is inserted in the dis- charge conduit between the discharge opening 67 and the above mentioned connecting point 75.

The emptying of the buffer tank normally takes place as a flow under the influence of gravity through the discharge conduit 68, the non-return valve 77, the shut-off valve 69, the hose coupling 70 and the rolled out hose 72 when the free end of this hose is connected to the filling pipe of a storage tank in the tank station after the opening of the shut-off valve 69.

However, a detector is also placed at the top of the buffer tank 64 which detector at a high level of propellant may send a signal to the pump 76 in the conduit loop 74 to start pumping propellant through the shut-off valve 69, the hose coupling 70 and the hose 72 to the filling pipe, and during this pumping, which serves to prevent propellant leaving the buffer tank 64 through the ventilation conduit and the flame filter 65, the non-return valve 77 closes and the Y-shaped connecting point 75 simultaneously functions as ejector. In rare cases, when the distance between the calibration apparatus 1 and the filling pipe is in excess of the length of the hose 72, the shut-off valve 69 has to be closed and the buffer tank 64 used as a provisional reception tank un¬ til the vehicle may be driven to the filling pipe to be emptied.

The tank and pump section 8 also contains power means to produce the necessary power for operating the discharge valves 20 of the standards 10 and for pumping propellant between the reception tank 5 and the buffer tank 64 and possibly from the buffer tank 64 to the filling pipe of the tank station.

For this purpose an electric generator 78 is placed in the frame 4 which generator is connected to one of the road wheels 2 through a belt drive 79, which preferably may be a V-belt drive.

The belt drive 79 comprises a first pulley 80, which is mounted on an existing brake drum 81 on the said road wheel 2, and a second pulley 82 on the axle of the generator 78.

The first pulley 80 consists of two rings 83, 84 which may be clamped together around the brake drum 81 the circumfe¬ rence of which has to be prepared in a suitable way. The rings 83, 84 are assembled by means of screws 85. To secure the rings 83, 84 against turning on the brake drum 81 bolts are screwed through threaded holes in the axially innermost ring 83 against the brake drum 81.

During transport of the calibration apparatus 1 the genera¬ tor 78 is driven and thereby delivers electrical power for charging an accumulator 87 through charging devices of the kind commonly found in ordinary automobiles, which charging devices guarantees that the charging current will be adap¬ ted to the state of charge of the accumulator 87, so that the accumulator 87 is charged with the strongest permissi- ble charging current if it is discharged, and correspon¬ dingly lets the generator deliver a no-load current if the accumulator is fully charged.

The accumulator 87 is for reasons of safety and fire pre- vention placed in the electronics sector 9.

The described embodiment of the tank and pump arrangement as well as the placing of a belt driven electrical genera¬ tor 78 at one of the road wheels 2 is connected to the con- ditions under which the propellant has to be conveyed back to a storage tank in a tank station and the energy consump¬ tion which is necessary for this process.

As the filling pipes at the storage tanks of a tank station are placed remote from the propellant pumps with the volume meters, which are to be controlled, the return transfer of the measured amounts of propellant is cumbersome.

It would be possible to let the propellant from a pump flow into a reception tank of c. 200-300 liter in the calibra¬ tion apparatus and after that drive the apparatus to the emptying place, but this is a time and work consuming acti¬ vity during which it will not be possible to undertake any calibrations at a pump.

It has therefore been decided to draw a hose 72 from the calibration apparatus 1 at its stand to the filling pipe of the storage tank.

Experiments have shown that it takes considerably more pum- ping work to pump a certain amount of liquid through 50 me¬ ters of hose without any difference in level than to let the same pump lift the same amount 1 meter and afterwards letting the amount of liquid flow the same length of hose through free fall.

After having been pumped from the reception tank 5 up to the buffer tank 64 the amount of propellant flows slowly by the influence of gravity through the hose 72 to the filling pipe of the tank station. The pump has to pump for c. 4 mi¬ nutes to pump the amount needed for a calibration of a pro¬ pellant pump whereafter it takes about half an hour for this amount to flow by free fall through 50 meters of hose 72 from the buffer tank 64. If the same pump had to pump the same amount of propellant through the same length of hose, but without any differences in level, it would demand twice the time for pumping and thereby twice the amount of energy.

Energy is therefore saved by using a reception tank 5 and a buffer tank 64 at two different levels. Excess time is de¬ manded to achieve this saving in energy, but, as the time of stay at a propellant pump also is about half an hour du¬ ring which, in addition to the brief fillings of the stan- dards, adjustments of the suspensions and readings and re¬ cordings of the results have to take place, this appears to be acceptable.

If the hose 72 should be run over, the flow of propellant through the hose will only be stopped as long as the hose is compressed independent of whether this compression takes a short or a long time.

If a solution had been chosen in which pumping was effected directly from a reception tank to a filling pipe then the o

pump would have to work under pressure during a long term compression of the hose, if f. inst. a vehicle inadvertent¬ ly stopped with a wheel on the hose. This might cause an overheating of the the pump which might be dangerous in an environment of propellant vapours.

It is true that the buffer tank 64 at times may be dis¬ charged by pumping through the above mentioned conduit loop 74, but this pumping is only done for a short time to pre- vent propellant from leaving the calibration apparatus through the ventilation hose and flow through the flame filter 65.

The necessary energy for pumping back the propellant has to be provided by the calibration apparatus 1 itself as it is too risky to collect energy for the calibration apparatus from the energy supply of the tank station through cables because the cables might be run over with a risk of de¬ struction and the conseqence of spark formation in an en- vironment in which drifting vapours of propellant may occur on the road surface.

The necessary energy is provided through the generator 78 and the accumulator 87 in the shape of electric current whereby the calibration apparatus is made into a self-suf¬ ficient system which may be used under all sorts of circum¬ stances.

Calibration of isolated unmanned pumps, at which there is no possibility of external electricity supply, is in this way made possible.

If a hydraulically operated discharge valve 20 is used with a standard 10 the necessary hydraulic equipment must be placed in the tank and pump section 8 together with a hy- draulic pump which may be driven by the accumulator.

However, the hydraulic equipment needs quite a large amount of power during the operation and if this power had to be provided in the shape of electricity, this might represent a danger of spark formation, and it is therefore preferred to use pneumatic energy which may be provided in the shape of a suitable fire preventing gas which is compressed into a pressure container 88. Suitable gasses may be nitrogen or carbondioxide.

The gas is supplied from one or several pressure containers 88 through a reduction valve of an as such known kind so that the gas may be collected at a suitable pressure and supplied to the activating means at the discharge valves 20.

A control panel 90 and the accumulator 87 are placed in the electronics section as these parts represent the greatest risk of spark formation.

The control panel 90 contains electronic means for time control of the discharge valves 20 of the standards 10, start and stop of the electrically driven pumps, which partly pump propellant from the reception tank tank 5 to the buffer tank 64, and partly from the buffer tank 64 through the branch conduit 74 to the hose 72 and the fil¬ ling pipe of the tank station, when there is a need for operation of the last mentioned pump 76, opening and clo- sing of the shut-off valve 69, and regulation of the char¬ ging of the accumulator 87 by the generator 78.

The electronic means in the control device also compris alarm systems which acustically and/or visually may an- nounce possible malfunctions of the calibrating apparatus. The control buttons for control of the individual functions may be placed in the control panel 90, but the control buttons are preferably placed in a special panel in the standard section 7 so that an operator may operate all functions in the calibration apparatus 1 from one and the same stand at the end of the standard section 7.

The necessary conduits and cable connections are passed through the fire-resistant bulkheads by means of packings which may withstand any fire which may break out in a sec¬ tion so that a fire may be limited to this section.

The use of electric wires for transfer of signals between the control panel 90 and various means in the calibration apparatus implies a danger of spark formation which might ignite the vapours of propellant in and around the appara¬ tus. It is therefore preferred to use optical conductors for the transfer of signals to the widest possible extent.

The necessary electronic optical relays are to the widest possible extent placed in the electronics sector 9.

The calibration apparatus 1 is, to achieve a protection against the weather and for reasons of safety, covered by a roof and doors and/or roll-fronts which permit the atten¬ dance of the apparatus. Besides, the apparatus in its en¬ tirety is lockable.

Both the bottom and the doors have ventilation openings to maintain the best possible conditions so that any remnants of propellant, which may have dripped off, may evaporate and be carried off by the wind during transport of the ca¬ librating apparatus from one-tank station to another.

Claims

C A I M S

1. The invention relates to a calibrating apparatus for control of volume meters, especially volume meters for de- livering highly inflammable liquids, f. inst. volume meters in the form of propellant pumps in the traffic sector, which calibrating apparatus (1) has at least one standard (10) designed with a determined volume and provided with a filling opening (31) and a discharge opening (19) connected to a reception tank (5), and in which the standard (10) and the reception tank (5) below the standard (10) are placed on a frame (4) provided with wheels (2), especially a trai¬ ler c h a r a c t e r i s e d in that the standard (10) or standards are suspended in a lockable cardan suspension, that the connection between the above mentioned discharge opening (19) or each of the discharge openings and the re¬ ception tank (5) consists of a. flexible discharge hose (60) which is provided with a remote controlled discharge valve (20), that the standard (10) or each of the standards has a foam top (14) with a cover (32), which foam top is connec¬ ted to the reception tank (5) through a ventilation hose, that a buffer tank (64) is placed at the top of the frame (4) and is connected partly to the reception tank (5) through a pipeline provided with pumps and partly to a hose (72) which may be rolled out from a hose drum (71) and which is designed to be connected to a filling pipe on a storage tank in a petrol station; that hydraulic or pre¬ ferably pneumatic (88) and electric power means (78-87) are provided in the frame (4), together with a control device (90) with means for controlling the said pumps and powe means (88, 78-87) and a time controlled remote-control o the discharge valve (20) or valves; that the frame (4) i divided into three sections by fire-resistant bulkheads (6) of which the standard section (7) contains the standar (10) or standards, the tank or pump section (8) contain

SUBSTITUTE SHEET 30

the reception (5) and buffer (64) tanks, the pumps (76), the hose drum (71) with the said hose (72), said power means and an electric generator (78) which is connected to one of the wheels (2) by means of a possibly releaseable 5 driving device (79-86), and the electronics section (9) contains the control device (90) and accumulators (87) for collecting the electric power produced by the generator (78) during transport.

10 2. Apparatus according to claim 1, c h a r a c t e ¬ r i s e d in that a standard (10) consists of a hollow body of revolution which in the position of use at the bottom has a measuring compartment (11), in the midddle a slender neck (12) with a window or a measuring glass (13) with mea-

15 suring lines (22) on the glass or on an adjacent ruler, and above has a foam top (14), that the measuring compartment (11) and the foam top each consists of two cones (15,16) placed with their apexes turned away from each other, while the bases of the cones (15, 16) are connected by a short

20 cylinder (17), that the measuring compartment (11) together with a part of the neck (12) has a volume which by means of a movable and fixable, interchangeable displacement body (23) may be adapted to a previously determined volume, that the foam top (14) has a volume which at least corresponds

25 to the volume of the measuring compartment (11) and at the top has a cover (32) which by gravity or preferably by spring power is kept in a closed position over a filling opening (31), that the foam top (14) in the upper part has a connection (34-37) for the ventilation hose, and that the

30 measuring compartment (11) at the bottom has the said dis¬ charge opening (19).

3. Apparatus according to claim 1 or 2, c h a r a c t e ¬ r i s e d in that the connections between ths neck (12) 35 and respectively the measuring compartment (11) and the foam top (14) consist of flange connections (25, 26), and that a ring (27) is inserted in the flange connection (26) between the foam top (14) and the neck (12), which ring on the radially outer side at diametrically opposite points has bearing stubs (28) which stubs (28) have a common axis and serve as a suspension for the standard (10).

4. Apparatus according to claims 1, 2 and 3, c h a r a c ¬ t e r i s e d in that the standard (10) or standards are suspended in bearings (38) in a rectangular frame consis¬ ting of angle bars (45) and long beams (52), which frame extends transversely of the apparatus and at least at one end is supported by a vertical threaded bolt (42) which is mounted immoveably in the longitudinal direction in such a way that the said end may be raised or lowered by turning the bolt (42), whereas each end of the frame (51, 52) is spring supported by means of a block (48) of elastomeric material.

5. Apparatus according to any of the previous claims, c h a r a c t e r i s e d in that the reception tank (5) is designed with relatively large dimensions in the horizontal direction and with a limited height and volume, and has an upper and a lower detector for detecting the liquid level.

6. Apparatus according to claim 5, c h a r a c t e ¬ r i s e d in that the buffer tank (64) compared to the re¬ ception tank (5) has a large volume and a sump (66) with a discharge opening (67) which may be connected to a dis- charge conduit (68) with a preferably remote controlled shut-off valve (69) and a hose coupling (70), that a con¬ duit loop (74) is inserted between the discharge opening (67) and a Y-shaped connecting point (75) between the dis¬ charge opening (67) and the chut-off valve (69), which loop is provided with a pump (76), and that a non-return valve

SUBSTITUTESHEET (77) is inserted in the discharge conduit (68) between the discharge opening (67) and the Y-shaped connection point (75).

7. Apparatus according to claim 6, c h a r a c t e ¬ r i s e d in that a ventilation conduit connects the recep¬ tion tank (5) and the buffer tank (64), and that a pressure balancing conduit at one end is connected to the top of the buffer tank (64) and at the opposite end has a flame filter (65).

8. Apparatus according to claim 1 and in which the wheels are provided with expanding brakes, c h a r a c t e ¬ r i s e d in that a first pulley (80) is secured to the pe- riferi of a brake drum (81), that a non-spark forming gene¬ rator (78) is placed in the frame (4) of the calibrating apparatus (1) which generator carries a second pulley (82), and that a drive belt (79), preferably a V-belt, is placed around the said pulleys (80, 81) in such a way that the ge- nerator (78) may be driven during transport of the appara¬ tus to charge an accumulator (87).

9. Apparatus according to claim 1 and in which pneumatic power means are employed, c h a r a c t e r i s e d in that a non-flammable gas, e. g. nitrogen or preferably carbondi- oxide, is compressed into a pressure container (88) and em¬ ployed as a power means, which gas is collected through a reduction valve (89).

10. Apparatus according to claim 1, c h a r a c t e ¬ r i s e d in that the control device (90), the means for controlling the pumps and power means and the remote con¬ trol of the discharge valve or valves (20) preferably are interconnected by optical conductors and that the necessary electronic, optical relays preferably are placed in the

SUBSTITUTESHEET electronics section ( 9 ) .

SUBSTITUTE SHEET