EP0518662B1

EP0518662B1 - Fluid discharge monitor system and method

Info

Publication number: EP0518662B1
Application number: EP92305351A
Authority: EP
Inventors: Simon Hugh Arnison James
Original assignee: Emco Wheaton UK Ltd
Current assignee: Emco Wheaton UK Ltd
Priority date: 1991-06-11
Filing date: 1992-06-11
Publication date: 1995-05-17
Anticipated expiration: 2012-06-11
Also published as: DE69202520D1; EP0518662A2; ATE122645T1; EP0518662A3; DK0518662T3; DE69202520T2; ES2072098T3; GB9112489D0

Abstract

An electronic apparatus for monitoring the discharge of fluid from the compartment of a transport container to a static tank comprising a means (25, 28, 31) for identifying the fluid stored in the compartment, a means (25, 28, 31) for communicating with a remote device at the static tank to determine the identity of fluid in the static tank and a means (25) for comparing the identity of fluid in the compartment with that of the static tank. The apparatus may further comprise means (25, 26) for preventing discharge of fluid from the compartment. <IMAGE>

Description

The present invention relates to a method and apparatus for monitoring the discharge of fluid from a compartment of a fluid transport container, such as a road or rail tanker.
Conventionally, fluid containers such as road tankers may comprise a plurality of separate compartments, each containing a different fluid, e.g. a different grade of petrol or diesel fuel. The compartments are loaded up at a filling point from a loading arm either via a fill cap at the top of the compartment, or a first valve, the foot valve, located at the underside of the container or via a second outlet valve, located at a more accessible position to one side of the container and coupled to the foot valve via a conduit extending therebetween. The outlet valve may comprise a conventional API (American Petroleum Institute) valve, the opening and closing of which is controlled by a pneumatic system associated with the tanker and by a safety mechanism which prohibits the opening of the valve unless it is mechanically engaged with a corresponding delivery hose. The foot valve may be controlled similarly. In an alternative arrangement, the API valve may be a solely manually operable valve not connected to the pneumatic system, whilst the foot valve is connected to and controlled by the pneumatic system. Alternatively, the API valve may be both manually and pneumatically operable, i.e. such that it must be pneumatically enabled before it can be manually opened.
The tanker then proceeds to a discharge point where each compartment is discharged via the outlet valve to a static tank located at the discharge point. Problems arise if the contents of a compartment are discharged into an inappropriate static tank, i.e. one designated for a different product. The contents remaining in the static tank and the new product will mix and be contaminated, and the tank will have to be drained before being usable again, the drained fluid being wasted. Even if the static tank is empty and the fluid discharged into it can be re-used, it is still an undesirable and time-consuming operation to transfer the fluid to the correct tank.
AU-B-602 791 discloses an electronic fuel delivery identification system and a method according to the preamble of claims 1 and 15 for fluid delivery between a dispensing vessel and a storage vessel electronically identified at the dispensing vessel. This system assumes that the delivery hose is connected to the correct receiving tank. Electrical signals are transmitted from this tag to a decoder provided at the dispensing tank. The data is used to identify the particular type of storage vessel ensuring that the correct fluid is dispensed into the tank.
According to one aspect of the present invention, there is provided an electronic apparatus for monitoring the discharge of fluid from a compartment of a transport container to a static tank via an associated outlet, and a fluid connection means between the outlet and the tank, comprising a means for identifying the fluid stored in the compartment, a means adapted to automatically communicate with a remote device at the static tank via the fluid connection means to determine the identity of the fluid stored, or intended to be stored, in the static tank, and a means for comparing the identity of the fluid in the compartment and that stored, or intended to be stored, in the static tank, characterised by further comprising a power source in the form of a chargeable battery system, operable to charge up from the electrical system of the transport container when the container is not discharging or loading fluid, and to disconnect or isolate itself from the vehicle electrical system during discharge or loading.
According to a second aspect, there is provided a method of electronically monitoring the discharge of fluid from a compartment of a transport container via an associated outlet to a static tank, comprising providing a means for identifying the fluid stored in the compartment, providing a means for automatically communicating with the static tank, and a comparison means, and including the steps of identifying the fluid stored in the container, automatically communicating with the static tank via a connection between the outlet and the static tank to determine the fluid stored, or intended to be stored, in the static tank, and comparing the identity of the fluid stored in the compartment with that stored, or intended to be stored, in the static tank; characterised by charging up a power source in the form of a chargeable battery system from the electrical system of the transport container when the container is not discharging or loading fluid, said power source disconnecting or isolating itself from the vehicle electrical system during discharge or loading.
The chargeable battery system provides a particularly safe power source for the apparatus and helps reduce the risk of any large charges accumulating in the apparatus during fluid discharge or loading. This is particularly important if the fluid is a flammable product such as diesel fuel or petrol and particularly if a communication means is used which relies on sending electrical signals via the outlet or inlet.
Preferably, the apparatus further comprises a means for preventing the discharge of fluid from the compartment if the comparison means indicates that the identity of fluid in the compartment is incompatible with or different from that of the static tank. Alternatively, or in addition to this, the apparatus may comprise a means for signalling the result of the comparison. The present invention also extends to a discharge system apparatus including the remote device.
Automatically communicating with the static tank to identify the fluid in the tank and comparing this with the fluid in the compartment enables the apparatus to alert the operator and/or to automatically cease the discharge if a mistake is made in the matching of the tank with the compartment. The present invention is particularly applicable to a transport container comprising a plurality of compartments to facilitate avoidance of discharge of the wrong compartment into a storage tank. The transport container may include a plurality of monitoring apparatuses, one for each compartment. Alternatively, a single apparatus may be provided, e.g. with common comparison means, separate communication means, etc.
It is often the case that there is an electrical connection between the outlet of a compartment and the static tank in order to enable any stray electrical charge on the transport container to be grounded, e.g. via an electrically conductive connector hose arranged between the compartment outlet and the static tank inlet. Advantageously, the communication means is adapted to send electrical signals to a remote device located at the static tank via a connection made between the outlet and the static tank and to receive electrical signals therefrom. Such signals can take the form of electrical pulses sent from the communication means to a remote device located permanently at the static tank. Preferably, the remote device does not include a power supply, for safety reasons, but is a passive device that will respond to signals from the communication means to provide a return signal identifying the static tank contents. The remote device may include a storage means, e.g. a capacitor, which is responsive to charging signals sent from the communication means and which, when discharging, provides sufficient power to enable the device to output the signal.
The remote device may also be adapted to signal the presence of an over-spill condition in the static tank due to over-filling of the tank.
Advantageously, the apparatus is operable to periodically switch to earth any stray charge in its operation or when not in operation. This may be done, for example, via a connection to earth provided by a vapour recovery hose connected between the transport container and the static tank at another point.
In an alternative to the signalling technique discussed above, the communication means may comprise one or more sensors located at the outlet point to directly sense the characteristics of the connection made at that point to identify the static tank contents. This will be described below in relation to further preferred features of the means for identifying the compartment contents.
In one embodiment the means for identifying the fluid stored in the compartment may comprise a memory means together with a manually operable input means to enable the operator to manually input the identity of the fluid in the container into the memory. Alternatively, sensors could be mounted in the tank to analyze the composition of the fluid in the compartment at all times. However, in a particularly advantageous embodiment the apparatus is further adapted to monitor the loading of the compartment with fluid from a loading arm via an associated inlet, the identifying means comprising a means adapted to automatically respond to or communicate with the loading arm to determine the identity of the fluid being loaded into the compartment.
This ensures that all stages of the loading and delivery process are monitored to prevent against any accidental loading or discharge of the wrong fluid. The apparatus may further comprise a means for signalling the identity of the fluid to the operator during loading.
The apparatus may operate with a compartment having the same inlet and outlet such that the loading and discharge communication occurs via the same connection, e.g. via the main API outlet valve of a compartment of a conventional fluid transport container. However, it may be preferred to load the compartment via a different inlet connection, e.g. via the foot valve, from that used during discharge and the present invention extends to an apparatus adapted for use in such circumstances.
The loading communication means may be similar to that of the discharge communication system and may comprise a sensor means for sending and receiving electrical signals from a remote device. However, preferably, the identifying means comprises sensors located at the inlet to directly sense the characteristics of the connection made between the inlet of the compartment and the outlet of the loading tank. In one embodiment, the identifying means comprises one or more Hall effect sensors disposable around the aperture of the inlet and adapted to sense the magnetic field of one or more magnets arranged around the outlet of the loading tank. The presence or absence of one or more of the magnets indicates to the sensors the type of fluid stored in the loading tank. This information may then be stored in an appropriate memory means and retrieved later for comparison during discharging.
Conventional fluid transport containers include a pneumatic control system for controlling the opening and closing of inlet and outlet valves of all compartments as described earlier. In one embodiment the means for preventing the discharge of fluid includes a control valve arrangable in the pneumatic system to pneumatically control the outlet valve to prevent discharge of fluid through the compartment outlet. The relevant outlet valve may be the API valve. Alternatively, where a manual API valve is used, the foot valve may be pneumatically controlled and disabled by the control valve accordingly in the event of a mismatch. In the case of a fluid transport container having a plurality of compartments a single control valve may be arranged in the system to prevent discharge of fluid from all compartments when the comparison means indicates an incompatible matching of one compartment with a static tank. Alternatively, a plurality of control valves, one per compartment, may be provided to prevent discharge from the particular compartment which has been incompatibly matched with a static tank.
If used in conjunction with a pneumatic control system, the apparatus may comprise a sensor arrangeable in the pneumatic system to detect operation of the pneumatic system and to disconnect the battery system from the vehicle electrical system accordingly. The apparatus may also comprise a further sensor operable to detect operation of the pneumatic system and to actuate the apparatus to monitor discharge or loading accordingly.
Where a manual API valve is used, the apparatus may also preferably comprise a means for monitoring the opening and closing of the valve to determine that, at the time of discharge to the static tank, the valve has not been opened after the transport container was filled. This "sealed package" concept enables precise filling of the static tank, as the volume of fuel carried by the transport container will have been measured at the filling point, and will not have changed since that time. Should this condition not be satisfied, the apparatus can prevent discharge of fluid and/or provide a warning signal. In one particularly advantageous embodiment the monitoring means may comprise a sensor arrangement, e.g. in the form of a magnet and Hall effect sensor, to remotely monitor the position of an internal element of the valve.
The present invention also extends to a fluid transport container having an apparatus as described above and a pneumatic control system.
Preferably, the method further comprises preventing the discharge of fluid from the compartment if the identity of the fluid in the compartment is incompatible with or different from that of the static tank.
Advantageously, the method further comprises providing a communication means operable to send or receive electrical signals via the connection made between the outlet and the static tank. Advantageously, the method further comprises providing a remote device located in or on the static tank, sending electrical signals from the communication means to the remote device and identifying the fluid of the static tank accordingly.
Preferably, the apparatus operates to ground stray charge periodically in its operation or when not in operation.
There will now be described, by way of example only, certain preferred embodiments of the present invention with reference to the accompanying drawings, in which:

Figure 1 shows a fluid transport container including a plurality of compartments;
Figure 2 shows a schematic layout of a monitoring apparatus according to the present invention;
Figure 3 shows a pneumatic control system for use in conjunction with the apparatus of Fig. 2;
Figs. 4 & 5 show a flow diagram used in the central processor of the apparatus of Fig. 2;
Figure 6 shows a remote device in position at the static tank;
Figure 7 shows a block diagram of the circuitry of the remote device of Figure 6;
Figure 8 shows a block diagram of the circuitry of a discharge sensor system at a compartment;
Figures 9 & 10 show a loading sensor in situ at the outlet of a compartment;
Figures 11 and 12 show an alternative remote device and discharge sensor system;
Figure 13 shows a manual API valve and an associated open/close monitor; and
Figure 14 shows a removable remote device and fluid link.

Referring to Figure 1, a fluid transport container in the form of a road tanker 1 comprising a plurality of compartments 2 is shown. Each compartment 2 may be accessed for fluid via an inlet/outlet API valve 3 connected via an associated foot valve 4 to the compartment 2. Each compartment 2 also includes an associated vapour recovery vent 5. These are connected via the common channels 6 and 7 to a vapour dump vent 8 and a vapour recovery adaptor 9. Each compartment also includes a dip tube and dip tube interlock system 10 for allowing access to the compartment 2 for measurement of the liquid level therein.
The inlet/outlet valves 3, foot valves 4, vapour recovery vents 5 and vapour dump vent 8 are all connected and controlled by a central pneumatic control system 11. The pneumatic control system 11 also controls the operation of guard bar interlocks 12 which operate to open or lock a pair of guard bars (not shown) over the inlet/outlet valves 3 to prohibit or permit access thereto.
The pneumatic control system 11 will be discussed in more detail in conjunction with Figs. 2 and 3. The elements of the pneumatic system associated with the inlet/outlet valves 3, foot valves 4, etc. enabling or disabling the valves from operation are well-known and will not be discussed in any detail herein.
In conventional operation, at the loading stage, one or more inlet loading arms are connected to the inlet valves 3 and a vapour recovery arm connected to the vapour recovery adaptor 9. Providing the pneumatic system is enabled and valves 3, 4 and 5 are open, the compartments 2 are loaded up with fluid and the vapours thereby displaced from the compartments and via the vents 5 and channels 6 and 7 are recovered through the vapour recovery hose. At the discharge stage, one or more of the valves 3 is connected via an appropriate hose to an associated static tank. If appropriate, a further hose is connected from an outlet of the static tank to the vapour recovery adaptor 9. Again, providing the pneumatic system is enabled and the valves 3, 4 and 5 are open, the contents of each compartment 2 are discharged into the associated static tank and the vapours displaced from the static tank collected via the recovery adaptor 9. During transport, the collected vapours are held in the common channels 6 and 7.
Referring to Fig. 2, there is shown an electronic monitoring system for use in conjunction with the pneumatic system of Fig.3. The monitoring system includes a first terminal box 20, connected to the electrical power supply of the vehicle on lines 21, to a battery pack 22 and to pressure switches 23, 24 located in the pneumatic control system 11. When the pneumatic system is not in operation, i.e. during the transport of liquid, the battery pack 22 is connected via the terminal box 20 to the vehicle power supply 21, for charging. When the pneumatic system is initially actuated, the pressure switch 23 senses this and operates the terminal box 20 to disconnect the vehicle power supply from the battery pack 22 and the rest of the monitoring system. This isolation of the monitoring system from the power supply is important for safety reasons. Once the pneumatic system is above a certain pressure, the pressure switch 24 operates the junction box 20 to connect the battery pack 22 to a central processor 25 of the monitoring system. The pressure switch 24 may switch at a slightly higher pressure than that of the switch 23 to ensure that the apparatus is disconnected before actuating the monitoring system.
The central processor 25 is connected to shut-off valves 26, operable to disable the pneumatic system, a display 27 and a plurality of junction boxes 28, one associated with each compartment 2 of the transport container, and which connect the central processor 25 to a series of sensors located within each compartment. The sensors typically comprise a wet sensor 29 which detects the presence or absence of liquid in the compartment, a pressure switch 30, which detects whether or not the pneumatic system for that compartment is in operation, and a sensor system 31 which communicates with the loading apparatus at the loading point and the static tank at the discharge point to identify the fluid being loaded and the fluid in the static tank.
The communication means for the loading and discharge stages can be the same. However, in a preferred embodiment, separate systems are used. In particular, for the loading stage, the loading sensor system may comprise a plurality of Hall effect sensors located in a coupling ring at the outlet valve 3. These interact with a plurality of magnets located in the corresponding connecting part of the associated loading arm. Specifically, the number and orientation of magnets around the loading hose is detected by the Hall effect sensors, to communicate the identity of the fluid being loaded into that compartment at that time. The identity of the fluid stored in that compartment is then transmitted to and stored in the central processor 25, for later comparison.
The monitoring system shown in Fig. 2 uses a single bus connecting the junction boxes in series. In alternative arrangements, the junction boxes may each be connected directly to the microprocessor 25.
Referring to Figs. 9 and 10, a load sensor 50 is shown in situ on an API outlet valve 3 of a compartment. The sensor 50 is clamped or bolted into position. Five or more Hall effect sensors 52 are recessed into the casing of the sensor body, which interact with one or more magnets located in the corresponding part of the associated loading arm. The valve 3 is shown insulated from the fluid conduit 53 by an insulating ring 54. Electrically isolating the valve from the vehicle in this way enables electrical signals to be sent from the valve (see below).
The sensor 50 may also comprise a further communicating link in the form of an electrical connection terminal 51 adapted to link the controlling microprocessor 25 of the tanker system with the loading apparatus. In the event of a warning signal from the tanker microprocessor the loading system will stop filling the tanker compartment. For example, an overspill sensor may be provided in the tanker such that, in the event of over-filling of a compartment, a signal will be sent to the loading system to cease operation.
The discharge sensor system preferably comprises a means for sending and receiving electrical signals via the connection made between the outlet valve 3 and the compartment 2 to an associated remote device located permanently at the static tank. Preferably, this remote device does not include a power source, for safety reasons, but includes a capacitor system for storing electrical pulses from the sensor system to charge up the remote device. Once charged, the remote device operates to send a coded digital pulse back to the discharge sensor on the counter. This signal identifies the characteristics of the static tank, and, in particular, the type of fluid stored or intended to be stored therein. The central processor 25 can then compare the identity of the fluid of the static tank with the fluid in the compartment to determine whether or not a correct fluid connection has been made. A signal may also be sent from the remote device to the central processor in the event of an overspill condition within the static tank.
Conventionally, the connection between the outlet valve 3 and the static tank has been conductive for earthing purposes. However, in the present system, the static tank end of the connection may be isolated from earth in order to enable the efficient charging up of the remote device. If so, it may be advantageous to ensure the earthing of the monitoring system as a whole via, for example, the vapour recovery connection. In one embodiment the monitoring system is electrically switched to earth, for a predetermined pulse during the interrogation of each remote device.
As a further safety measure, suppressor diodes may be fitted in the discharge sensor system and in the remote device to pass to earth any voltage detected greater than 20V.
Fig. 6 shows a remote device 200 in position on the inlet connection 201 of a static tank 202. The connection 201 is electrically isolated from the static tank by an insulating ring 203. This is to facilitate the charging up of the remote device 200 and the subsequent transmission of electrical pulses by the remote device 200. The remote device 200 may be earthed by a further connection 204 to the fluid pipe of the static tank or to any other suitable earthing point.
Referring to Fig. 7, the remote device is electrically connected to the hose connection 201 on the line 205 and to earth on the line 206. The device includes a conventional electromagnetic interference absorber 207, which operates to absorb and filter out stray high frequencies, and a voltage surge suppressor 208 comprising, for example, a plurality of break-down diodes, which operates to pass to earth any large voltage surges on the line 205.
In operation, a charging pulse is sent from the sensor system of the compartment, over the connection between the outlet of the compartment and the inlet of the static tank and along the line 205 to charge up the storage capacitor 209 via the diode 210 and resistor 211. The charge on the capacitor 209 is discharged along line 213 to power an encoder chip 214. The encoder chip will operate as soon as the voltage on the line 213 rises above a certain level to send a characteristic digital signal from the output 215 via the coupling capacitor 216 along the line 205. The encoder chip 214 may comprise any suitable conventional chip. Preferably, the chip includes a means for manually selecting the appropriate output to reflect the contents of the fluid in the static tank, e.g. thumbwheel switches. The output signal sent may use pulse width modulation, the relative timing of digital pulses etc., or any other means to convey information regarding the static tank.
Referring to Fig.8, the discharge sensor system at the compartment comprises a decoder chip 300, opto- isolator connectors 301 and 302, through which the sensor system sends information to, and receives instructions from the central processor 25, a latching circuit 303 and a switching circuit 304, operable to earth the circuit. Signals to and from the remote device are sent and received on line 305 and the circuit is powered from the supply rail 306. In operation, the central processor operates to sequentially activate the sensor system in each compartment. Specifically, the central processor 25 sends a signal via opto-isolator 302, to switch on transistor 307 to connect the supply rail 306 to the line 305 for a short burst, e.g. 200 microseconds. This charging pulse is sent via line 305 to charge up the remote device 200. Simultaneously the transistor 308 is switched on to activate the decoder chip 300. The latching circuit 303 operates to keep the transistor 308 activated after the charging pulse has terminated. During this time the decoder chip 300 operates to sense the characteristic signal output by the remote device 200 and to output the decoded information to the central processor 25 via the opto-isolator 306. After a certain period of time, the latching circuit 303 ceases to maintain the potential on the transistor 308 and the decoder is switched off.
The sensor also includes a circuit 304 which may be activated by the central processor after this time to switch line 305 to earth, so as to dispose of any stray charges present on the connector hose between the sensor and the remote device.
The line 305 includes an electromagnetic interference absorber 310 and a voltage suppressor circuit 311 of the same construction and function as the absorber and suppressor at the remote device.
Preferably, the central processor operates the sensor system of each compartment in turn, such that a charging pulse is sequentially sent from each sensor circuit. The total time for each cycle of operation for each sensor, from the sending of the charging pulse to the earthing of the connector line, may take of the order of 300 milliseconds. In order to conserve battery power, the latching circuit 303 may operate to switch the decoder chip 300 on for only a portion of this time, e.g. 800 microseconds or so, or the time it takes for the central processor to interrogate each sensor system.
Fig. 11 shows an alternative encoder circuit from that of Fig. 7. The circuitry includes an additional logic circuit 400 adapted to monitor the condition of an over-spill in the static tank from a sensor connected on line 401. Additionally, the encoder is adapted to communicate with the discharge sensor system via two lines 402 and 403. As with the circuit of Fig. 7, the encoder circuitry includes a diode 404, resistor 405 and capacitor 406 arrangement to power an encoder chip 407. The circuitry further includes an electromagnetic interference absorber 408 and a breakdown diode 409, which operate in the same manner as the elements of the circuit Fig. 7.
In operation, a charging pulse along the lines 402 and 403 charges the capacitor 406, which then discharges via the resistor 405 to power the encoder 407. Additionally, the discharge of the capacitor charges the logic circuit 400 which communicates the presence of an over-spill condition to the encoder 407. An output signal, representing the contents of the fluid in the static tank and the presence or absence of an over-spill condition, is sent from the output 410 of the encoder 407 via the coupling capacitor 411.
The encoder circuit of Fig. 11 is adapted to communicate with the discharge sensor system of Fig. 12. In order to provide a higher current to this discharge sensor system, the coded signal is sent via a transistor 412.
Referring to Fig. 12, the alternative discharge sensor system shown therein comprises a decoder circuit 500, a latch circuit 501, and opto- isolator circuits 502 and 503, which are connected to lines from and to the central microprocessor of the control system. As before, signals from the central processor operate the latch circuit 501 to send control pulses to the remote device, on the lines 508 and 509 and to charge the decoder circuit 500. In order to improve the isolation between the control circuitry and the hose connection line to the static tank, a number of isolating switch circuits and an opto-isolator circuit have been introduced.
In particular, the latch 501 controls a switch integrated circuit 505 to send a command pulse on line 506 to the second switch circuit 507, which then sends an output pulse to the decoder on lines 508 and 509. The latch 501 also controls the switch circuit 505 to send a charging pulse on line 510 to enable the decoder circuit 500. In view of the necessity of monitoring over-spill at all times during the filling of the static tank, a charging pulse is sent at repeated intervals during the filling operation. Return signals on the lines 508 and 509 are routed via the switch circuit 507 along the lines 511 and 512 to the opto-isolator 513. This then sends a signal on line 514 to the decoder circuit 500. The decoder 500 communicates with the opto-isolator circuit 503 and the processor via a voltage change switching integrated circuit 515. The circuit 515 enables the decoder to be operated at a lower voltage than the processor circuitry. This then enables an optimum choice of voltage values for the discharge sensor and encoder system. The choice of the appropriate circuit for each of the switch components would be a routine matter for one skilled in the art.
In a further alternative embodiment, the load sensor and remote device may each comprise a tuned circuit set at the same resonant frequency. This enables a constant and earthed d.c. connection to be made between the load sensor and remote device, whilst allowing information in the form of a.c. or pulsed signals to be generated and passed between the load sensor and remote device. Use of a constant d.c. connection disposes of any stray charge on the hose connection, resulting in a particularly safe apparatus.
Fig. 3 shows a pneumatic control system for use with the monitoring system of Fig.2. The pneumatic system includes a source of air pressure 40 connected to pneumatic switches 41, 42 and 43 associated with the vapour recovery vent, dipstick interlock and foot valve, respectively, of each compartment. The source of pneumatic pressure is also connected, via a separate line, to an interlock system 44 associated with the inlet/outlet valve of each compartment. Application of air pressure to these pneumatic switches causes the vapour recovery vent and foot valve to open and to free the dipstick interlock system to enable a measurement of liquid level to be made. The interlock systems 44 are conventional ones, such that the inlet/outlet valves will only open when pressure is supplied and when the valve is mechanically interconnected to a corresponding valve.
The pneumatic supply 40 is also connected to pneumatic switches 45 associated with the bar locks 12. On application of pneumatic pressure, the switches operate to open the bar locks to enable access to the inlet/outlet valves. The switches 45 also operate further pneumatic switches 46 which control supply of air to associated elements in the vehicle braking system, so as to apply the brakes when the pneumatic system is in operation.
The pneumatic system further includes pressure switches 23 and 24 and a series of shutdown valves 26 as described with reference to Fig.1. Shut-down valves 26 are operable by the central processor 25 to cut the supply of air pressure to the interlock systems 44 of all compartments so as to terminate discharge or loading of fluid from or to the compartment 2. The shut-down valves 26 may also include a manual push button valve operable to cut the supply to all the API interlock systems 44.
In a vehicle including a manually operable API valve, the interlock systems 44 may be omitted, or may operate in combination with the mechanical means for opening and closing the valve. Where the interlock systems 44 are omitted, the shut-down valves are arranged in the circuit to disable the foot valves 43 in the event of shut-down signal from the central processor 25.
The pneumatic system may also include an overspill detector 47, which operates to detect excess loading of a compartment and to operate the dump system 48 to open the vapour dump vent 8.
Figs. 4 and 5 show a flow diagram of the control steps carried out by the central processor 25 for each compartment during loading and discharge. The processor 25 generally operates to enable the pneumatic control system. Only in the event of a detected error does the central processor operate the shut-down valves to disable the system.
In box 100, the wet sensor 29 is read to determine whether or not there is any fluid in the compartment. If not, the program proceeds to steps 101 and 102 to determine whether or not the system is loading or discharging. If the system indicates both loading and discharging at the same time, there is clearly an error and the program proceeds to step 103 where the shut-down valves are enabled and a fault indication provided on the display 27.
If the system is loading, the program proceeds to step 104 to read the load data identifying the fluid being loaded into the compartment and to indicate an empty condition on the display 27. If discharging, the system proceeds via step 105 to read the discharge data identifying the fluid in the static tank and to display both the information regarding the product in the static tank and an empty condition. If neither loading or discharging, the program proceeds to step 107 to merely display an empty condition.
If the sensor indicates at step 100 that liquid is present in the tank the program proceeds to steps 111 and 112 to determine whether or not the system is loading or discharging. If the system indicates both conditions, the shut-down valves are again initiated and a fault message indicated at step 113.
If loading, the system proceeds to step 114 to read the load data associated with the liquid being loaded. At step 115 it is determined whether or not this is the first reading being made. If it is, the program proceeds to store the load data and to display the product being loaded in the compartment. If not, the program proceeds to 117, to compare the data previously stored with that presently in the store. If the result of the comparison is positive, the program continues to display the product being stored in the compartment at step 118. If the result is negative, i.e. the same product is not still being loaded, the shut-down valves are again initiated and a fault message provided on the display. This prohibits the loading in of two different products into the same compartment.
If the system is determined to be discharging at step 120, the program proceeds to step 121, where the output of the pressure sensor is read to determine whether or not the pneumatic system for that compartment is still in operation. If the answer is negative, the discharge has either not been commenced or has finished, and the program proceeds to steps 122 and 123 where the discharge data associated with product in the static tank is read and the load data associated with the product presently in the compartment is retrieved from the microprocessor memory, and to step 124 where both sets of data are displayed.
If the result of step 121 is positive and the system is enabled for discharge of fluid from the compartment, and the system proceeds to steps 125 and 126 where the data of the static tank is read and the data for the compartment is retrieved, and then to step 127 where the identity of the fluid in the compartment and in the tank is compared. If the result of the comparison is acceptable, that is, the identity of the liquid in the compartment and in the tank is the same or an acceptable mixture, the program proceeds to step 128 where the product in the compartment and in the static tank is displayed. If the result of the comparison is unacceptable, the program proceeds to step 129 to energise the shut-down valves and to display a fault condition together with the product in the compartment. Thus, the system prevents discharge of fluid from compartment into the static tank.
If the system is neither loading nor discharging, the program proceeds to step 130 to see whether or not the pneumatic system for the compartment is in operation. If it is, the system proceeds to steps 131 and 132 to retrieve the load data and to enable the shut-down valves and to display a fault message together with an indication of the product in that compartment.
If the system is neither loading nor discharging and the pressure system is not energised for that compartment, the program proceeds to step 133 to retrieve and display the load data associated with that compartment.
Fig. 13 shows a manually operable API valve 600 including a pivoting lever 601 movable to horizontally displace valve element 602 to open and close the valve. The mechanical elements of the valve are entirely conventional and will not be described in any detail. On the valve element 602 is mounted a magnet 603 which interacts with a remote Hall effect sensor 604 mounted external to the valve. The sensor 604 is connected to microprocessor 25 of the control system to monitor the opening and closing of the valve, as indicated by the presence and absence of the magnet. This enables the control system to validate the delivery of the whole contents of the compartment of the tanker to the static tank, as the valve should only be opened and closed once at the filling point before prior to the delivery at the static tank. Should this condition not be satisfied, the apparatus can prevent discharge and/or send a warning signal. The use of the Hall sensor and magnet arrangement enables accurate monitoring of the actual opening and closing of the valve.
Fig. 14 shows an encoder remote device 700 of the type illustrated in Fig. 7 together with a removable elbow joint 701. Typically, static tanks will include a projecting pipe which may be fitted with a remote device of the invention as illustrated in Fig. 6. In some cases, however, the fluid entry is via a hole flush with the ground. In these circumstances, it can be difficult to fit a remote device and to ensure electrical isolation of the hose from the earth. In such circumstances a removable elbow joint 701 can be used, constructed to ensure electrical isolation of the hose by means of appropriate insulating elements at the connection point, e.g. similar to those used on the embodiment of Fig. 6, and pre-fitted with a remote device 700. The elbow joint 701 is removably screwed to the fill pipe 702 of the static tank.

Claims

An electronic apparatus for monitoring the discharge of fluid from a compartment of a transport container (1) to a static tank (2) via an associated outlet (3, 4) and a fluid connection means between the outlet and the tank, comprising a means (25, 28, 31) for identifying the fluid stored in the compartment, a means (25) adapted to automatically communicate with a remote device at the static tank (2) via the fluid connection means to determine the identity of the fluid stored, or intended to be stored, in the static tank (2), and a means (25) for comparing the identity of the fluid in the compartment (1) and that stored, or intended to be stored, in the static tank (2), characterised by further comprising a power source in the form of a chargeable battery system (22), operable to charge up from the electrical system of the transport container (1) when the container is not discharging or loading fluid, and to disconnect or isolate itself from the vehicle electrical system during discharge or loading.
An apparatus as claimed in claim 1, in which the communication means (25) is arranged to send electrical signals to a remote device (200) located at the static tank (202) and to receive electrical signals therefrom.
An apparatus as claimed in claim 2, including the remote device (200) and in which the remote device does not include a power supply but is a passive device that responds to signals from the communication means (25) to provide a return signal identifying the fluid of the static tank (202).
An apparatus as claimed in claim 3, wherein the remote device (200) includes a charge storage means (209) which is responsive to charging signals sent from the communication means and which, when discharging, provides sufficient power to enable the remote device to output a return signal.
An apparatus as claimed in claims 2, 3 or 4 in which the apparatus is operable to periodically switch to earth any accumulating stray charge.
An apparatus as claimed in any preceding claim in which the identifying means (25, 28, 31) comprises means for storing a signal representation of the identity of the fluid stored in the compartment.
An apparatus as claimed in any preceding claim further adapted to monitor the loading of the compartment with fluid from a loading arm via an associated inlet, the identifying means comprising a means adapted to automatically respond to or communicate with the loading arm to determine the identity of the fluid being loaded into the compartment.
An apparatus as claimed in claim 7, in which the identifying means comprises sensors (31) located at the inlet to directly sense the characteristics of the connection made between the inlet of the compartment and the outlet of the loading arm.
An apparatus as claimed in claim 7 or 8, in which the identifying means comprises one or more Hall effect sensors (52) disposable around the aperture of the inlet and adapted to sense the magnetic field of one or more magnets arranged around the outlet of the loading arm.
An apparatus as claimed in any preceding claim further comprising a means (26) for preventing discharge of fluid from the compartment if the comparison means indicates that the identity of fluid in the compartment is incompatible with or different from that of the static tank.
An apparatus as claimed in claim 10 in which the means for preventing the discharge of fluid includes a control valve arrangeable in the pneumatic system of a transport container to prevent discharge of fluid through the compartment outlet.
An apparatus as claimed in any preceding claim comprising a means for signalling the result of the comparison of the identity of the fluid in the compartment and that of the static tank.
An apparatus as claimed in any preceding claim comprising a means (51) for monitoring the opening and closing of the inlet and outlet of a compartment of the tanker to provide a subsequent indication of the recurrence of an opening and closing.
A fluid transport container (1) including an apparatus as claimed in any of claims 1 to 13.
A method of electronically monitoring the discharge of fluid from a compartment of a transport container (1) via an associated outlet to a static tank (202), comprising providing a means for identifying the fluid stored in the compartment, providing a means (25) for automatically communicating with the static tank, and a comparison means, and including the steps of identifying the fluid stored in the container, automatically communicating with the static tank via a connection between the outlet and the static tank to determine the fluid stored, or intended to be stored, in the static tank, and comparing the identity of the fluid stored in the compartment with that stored, or intended to be stored, in the static tank; characterised by charging up a power source in the form of a chargeable battery system (22) from the electrical system of the transport container (1) when the container is not discharging or loading fluid, said power source disconnecting or isolating itself from the vehicle electrical system during discharge or loading.
A method as claimed in claim 15 further comprising preventing the discharge of fluid from the compartment if the identity of the fluid in the compartment is incompatible with or different from that of the static tank.
A method as claimed in claim 15 or 16 comprising providing a communication means operable to send or receive electrical signals via the connection made between the outlet and the static tank, and providing a remote device located in or on the static tank, and further comprising sending electrical signals from the communication means to the remote device and identifying the fluid of the static tank accordingly.