AU2020217825A1 - Pneumatic tanker - Google Patents

Abstract

A system for unloading a particulate material from a container (unloading system) is disclosed. In one aspect, the unloading system comprises a discharge system for carrying away the material from one or more compartments to a container outlet, and a control system for controlling operation of the unloading system. The discharge system comprising a discharge valve positioned at a material outlet for each compartment to control the discharge of material from the compartment into a discharge line. The unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve being adjustable. The control system comprising at least one pressure sensor for the discharge line, the control system in use monitors discharge line pressure continuously and controls the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow.

Description

PNEUMATIC TANKER

PRIORITY DOCUMENTS

[0001] The present application claims priority from Australian Provisional Patent Application No. 2019900393 titled“PNEUMATIC TANKER” and filed on 7 February 2019, the content of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to an unloading system for a container for a particulate material, and to a container for a particulate material comprising such a system. Both a container in the form of a silo and a trailer-mounted container (or tanker) comprising such a system are also disclosed.

BACKGROUND

[0003] Pneumatic tankers are used to store and transport dry granular material, generally referred to as product. A typical tanker will comprise an enclosed tank, comprising at least one hopper in connection with a product pipe, which carries product from the hopper to a storage location such as a silo. Movement of the product from the hopper to the product pipe and storage location is achieved through the use of a compressed air system.

[0004] Typical compressed air systems comprise an air compressor or blower in fluid connection with a manifold via a“hot hose”, the manifold is in fluid connection with four valves, being the“top air” valve, the "aerator” valve, the“product line” valve and the“blow down” valve. The“top air” valve is in fluid connection with the top of the tank, and provides air flow to the tank, capable of creating a pressure build up within the tank. The“aerator” valve is in fluid connection with an aeration system located within each hopper, which acts to“fluidize” the product, encouraging it to flow out of discharge valves located at the base of each hopper. The“product line” valve is in fluid connection with the product line, which itself is in fluid connection with the discharge valves at the base of each hopper, where the flow of air through the product line carries the product out to the product pipe.

[0005] Typical pneumatic tankers risk damage to the product and the tanker itself due to blockages and breakages. There is also risk of operator injury in the event of an air pressure leak.

[0006] There is also a need for product to be discharged across varying distances and heights, while ensuring that the discharge is consistent with the mix of product and air to maintain the flow of product, not allowing the product to stall causing blockages in the product line. Of course these issues are not limited to pneumatic tankers.

[0007] It is against this background and the problems and difficulties associated therewith that the present invention has been developed.

[0008] Certain objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

SUMMARY

[0009] According to a first aspect, there is provided a system for unloading a particulate material from a container (unloading system), the unloading system comprising a discharge system for carrying away the material from one or more compartments to a container outlet, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at a material outlet for each compartment to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

[0010] In one form, in use, if the discharge line pressure increases beyond a set range, then the control system will open the boost valve further in response.

[0011] In one form, in use, if the discharge line pressure decreases beyond a set range, then the control system will close the boost valve somewhat in response.

[0012] In one form, there is for each compartment a discharge line pressure sensor adjacent to the respective discharge valve, and in use, the control system monitors the discharge line pressure sensor associated with the compartment being emptied at the time.

[0013] In one form, the unloading system will unload one compartment at a time. [0014] In one form, the control system further comprises a pressure sensor for each compartment, and in response to a sensed compartment pressure and the sensed discharge line pressure continuously coordinating operation of the or each discharge valve and the boost valve via a feedback loop, to control and maintain material flow in the discharge line.

[0015] In one form, in use, if the discharge line pressure reaches or approaches the compartment pressure, then the control system will close the discharge valve for that compartment and open the boost valve further. This should have the effect of clearing any blockage before material flow is reinstated.

[0016] In one form, the unloading system further comprises a gas pressurisation system for pressurising a compartment or each of a plurality of compartments contained within the container, and wherein the control system coordinates operation of the gas pressurisation system and the discharge system to effect unloading.

[0017] According to a further aspect, there is provided a container for a particulate material, the container comprising at least one storage compartment, the or each compartment comprising a hatch for access thereto, a discharge hopper, a lowermost material outlet, the container further comprising a system for unloading the particulate material from the container (unloading system), the unloading system comprising a discharge system for carrying away the material from the or each compartment, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at the or each material outlet to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

[0018] In one form, there is for each compartment a discharge line pressure sensor adjacent to the respective discharge valve, and in use, the control system monitors the discharge line pressure sensor associated with the compartment being emptied at the time.

[0019] In one form, the container further comprises a container vent valve under the control of the control system. [0020] In one form, there is for each compartment a particulate aerator under the control of the control system.

[0021] In one form, the container is trailer-mounted, so as to be transportable.

[0022] In one form, the container comprises a silo.

[0023] According to a further aspect, there is provided a pneumatic tanker for a particulate material, the tanker comprising at least one storage compartment, the or each compartment comprising a hatch for access thereto, a discharge hopper, a lowermost material outlet, and a system for unloading the particulate material from the container (unloading system), the unloading system comprising a discharge system for carrying away the material from the or each compartment, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at the or each material outlet to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

[0024] According to a further aspect, there is provided a silo for a particulate material, the silo comprising at least one storage compartment, the or each compartment comprising a hatch for access thereto, a discharge hopper, a lowermost material outlet, and a system for unloading the particulate material from the container (unloading system), the unloading system comprising a discharge system for carrying away the material from the or each compartment, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at the or each material outlet to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line. [0025] According to a further aspect, there is provided a method of operation for the above described control system, the method comprising the steps of continuously monitoring the pressure sensor for each compartment, and the pressure sensor for the discharge line, and in response to a sensed compartment pressure and a sensed discharge line pressure continuously coordinating operation of the discharge valve and the boost valve via a feedback loop, to control and maintain material flow in the discharge line.

[0026] In one form, the method comprises the further step of if the discharge line pressure reaches or approaches the compartment pressure, then the control system will close the discharge valve for that compartment and open the boost valve.

[0027] In one form, the“boost” valve is in fluid connection with atmosphere and is used to control overall pressure levels throughout the compressed air system.

BRIEF DESCRIPTION OF DRAWINGS

[0028] Embodiments of the present invention will be discussed with reference to the accompanying drawings wherein:

[0029] Figure 1 is a side view of a trailer-mounted container, or tanker;

[0030] Figure 2 is a schematic illustration of a control system for the unloading system of the trailer- mounted container of Figure 1;

[0031] Figure 3 is a side view of a silo;

[0032] Figure 4 is a front end view of the silo of Figure 3;

[0033] Figure 5 is an opposing side view of the silo of Figure 3; and

[0034] Figure 6 is a rear end view of the silo of Figure 3.

DESCRIPTION OF EMBODIMENTS

[0035] Referring now to Figure 1 , where there is illustrated a trailer-mounted container or tanker 1. The container comprises a shell 2, preferably of aluminium, and, in this embodiment, divides into two generally cylindrical and horizontally disposed lower product compartments which are arranged along a common horizontal axis. Each compartment is provided with a hatch 4 for access thereto, a discharge hopper 6 and a lowermost material outlet (not visible) at the bottom of the hopper 6. [0036] A blower or compressor is typically mounted on a tractor that is used to haul the tanker, and is connected to a pressure feed line 10 (often referred to as a hot hose) for the container via a connector 12. In an alternative, the tanker 1 could be fitted with its own blower or compressor. Moreover, an accumulator may be employed to ensure consistency of supply.

[0037] An unloading system is also provided for unloading the container.

[0038] The unloading system comprises a gas pressurisation system for pressurising each of the plurality of compartments in order to aid emptying of these, and a discharge system for carrying away the product from the or each compartment to an outlet. Operation of the unloading system involves effective coordination of the pressurisation system and the discharge system.

[0039] The discharge system comprises a discharge valve (not visible) positioned at each material outlet to control the discharge of material from compartment into a discharge line 20. The discharge line 20 comprises pipework extending below each discharge valve to the container outlet 22.

[0040] Next provided is a plurality of electronically controlled valves. For each compartment, there is an aeration valve, and one of the aforementioned discharge valves. A vent valve in the container services both compartments.

[0041] A plurality of separate lines of pipework extend from the pressure feed pipe 10, so as to form a manifold with the feed pipe 10.

[0042] An aerator line 30 extends from the feed pipe 10 to each aerator, and comprises one of the aerator valves 32 in the line. The aerator valve operates to control the amount of air supplied to the aerator.

[0043] A boost line 40 extends from the pressure feed line 10 to the discharge line, and comprises a boost valve 42 in the line 40. The boost valve 42 operates to control the amount of air introduced to the discharge line, and comprises a position feedback function via which information regarding its position (i.e. closed and the extent to which it is open) is fed back to the control system.

[0044] A tank vent line 50 extends from the tank to the discharge line 20, and comprises one of the tank vent valves 52 in the line, which vents to atmosphere.

[0045] A manifold purge line 60 extends from the pressure feed pipe 10 to the discharge line, and comprises a purge valve 62 in the line. The purge valve 62 operates to purge the manifold when required. [0046] A plurality of gas pressure sensors, which in this case comprise electronic gas pressure transducers, are provided. The transducers sense internal gas pressure within the compartments and sense internal gas pressures within the pressure feed line (hot hose) and the discharge line (product hose) and convert the sensed gas pressure into an electronic signal. To this end (and with reference to Figure 2), there is provided a tank pressure sensor 70, a manifold pressure sensor 72, a first discharge pressure sensor 74, a second discharge pressure sensor 76 and a‘control air’ pressure sensor 78.

[0047] The unloading system further comprises a control system for controlling the operation thereof. The control system controls operation of the valves 32, 42, 52 and 62 in response to pressure reading feedback from the pressure sensors 70, 72, 74, 76 and 78. That is to say, the control system receives input from the pressure sensors (transducers) and then sends signals to the valves to control valve fimctions and system operation in turn.

[0048] Accordingly, the control system may include a variety of components. Exemplary components may include those that monitor electric signals, switch electric signals, perform sensing functions, and govern activation and deactivation of the valves.

[0049] Further, the control system may comprise a processor, a memory, storage, and a user interface 80. The control system may be controlled by software. The control system may provide users with precise control, diagnostic information and performance information for governing the unloading system. In this case a programmable logic controller (PLC) 82 is employed.

[0050] A salient feature of the present disclosure is how the control system will monitor discharge line pressure (via discharge pressure sensors 74 and 76) continuously, adjusting an extent of boost valve 42 opening in response, to control and maintain material flow in the discharge line 20.

[0051] A further salient feature of the present disclosure is how operation of the discharge valves and the boost valve 42 is coordinated by the control system to control discharge of the product to control and maintain material flow in the discharge line 20, and prevent and/or clear blockages.

[0052] For instance, if the discharge line pressure decreases beyond a set range (indicating an increased flow rate and reduced flow resistance), then the control system will close the boost valve 42 somewhat in response.

[0053] If the discharge line pressure increases beyond a set range (indicating a decreased flow rate and increased flow resistance), then the control system will open the boost valve 42 further in response. [0054] If the discharge line pressure reaches or approaches the compartment pressure, this likely indicates a blockage in the discharge line, so the control system will close the discharge valve for that compartment and open the boost valve 42 further. The control system will additionally sound an alarm to gain the attention of the operator.

[0055] It will be appreciated that the pressures at which the various actions are carried out may vary according to container configuration and material characteristics, and may need to be determined by way of some tuning of the system. To this end, the pressures provided herein are intended to be illustrative only.

[0056] Exemplary operation of the tanker is discussed below.

[0057] When connecting the tanker 1 to a silo the operator will: a. Remove product dust cap from product pipe; b. Remove product hose from hose tube; c. Connect product hose to the tanker 1 and silo; d. Open silo inlet valve; e. Start silo dust extractor; f. Connect blower hose to pressure feed line 10 (hot air inlet) on the manifold.

[0058] In this example, a user starts operation of the system such as by flipping a switch that sets the control system to work, monitoring and controlling operation of the unloading system on a near continuous basis.

[0059] When tanker unload is required, exemplary control system operation is as follows: a. Tank vent valve 52 is closed; b. Aerators are activated by the aerator valves 32; c. Pressure inside tank builds to unload pressure of approx. 140 kPa (needs to be adjustable) in 2 mins, tank pressure sensor 70 sends pressure to control system; d. When pressure in the tank reaches 140 kPa, the control system opens the boost valve 42 to 45 degrees with position feedback provided to control system from boost valve 42; e. Control system opens rear discharge valve (for the rear compartment) fully; f. Control system monitors product discharge pressure via pressure discharge sensor 76 (set point approximately 30 kPa). If the discharge pressure shows product resistance to flow (slow flow will give a higher pressure) the control system will increase boost by opening the boost valve 42 further. A lower pressure will indicate reduced resistance, in this case the control system will reduce boost by closing the boost valve 42 somewhat. If the discharge pressure reaches a yet to be determined set point (approximately 60 kPa), then the control system will close the discharge valve and open the boost valve 42 to 100% (i.e. fully open) until the pressure in the discharge line reaches a set point (approximately 20 kPa) then open the discharge valve again to let product flow resume, the control system will then return to controlling the discharge pressure; g. Unloading of rear compartment takes approx. 17 mins (in this case) with pressure

fluctuating between 130 kPato 145 kPa; h. When tank pressure drops below 100 kPa in approx. 30 seconds, the control system will close the rear compartment discharge valve, 10 seconds later the control system will close the boost valve 42; i. When pressure in tank reaches 140 kPa again, the control system opens boost valve 42 to 45 degrees; j. Control system opens front compartment discharge valve (pinch valve) fully;

k. Control system monitors product discharge pressure via pressure discharge sensor 74 (set point approximately 30 kPa). If the discharge pressure shows product resistance to flow (slow flow will give a higher pressure) the control system will increase boost by opening the boost valve 42 further. A lower pressure will indicate reduced resistance, in this case the control system will reduce boost by closing the boost valve 42 somewhat. If the discharge pressure reaches a yet to be determined set point (approximately 60 kPa), then the control system will close the discharge valve and open the boost valve 42 to 100% (i.e. fully open) imtil the pressure in the discharge line reaches a set point to be determined (approximately 20 kPa) then open the discharge valve again to let product flow resume, the control system will then return to controlling the discharge pressure;

[0060] When a cleanout operation is to be performed, the control system operates as follows: a. When pressure in tank reaches 140 kPa, the control system then opens the rear discharge valve (pinch valve) fully; b. Control system opens boost valve to 45 degrees position; c. When pressure drops below 100 kPa in approx. 30 seconds, the control system will close the rear discharge valve 10, seconds later the control system will close the boost valve

42; d. When pressure in tank reaches 140 kPa, the control system then opens the front discharge valve (pinch valve) fully; e. Control system opens boost valve to 45 degrees position; f. When pressure drops below 100 kPa in approx. 30 seconds, then the control system will open the rear compartment discharge valve (both front and rear discharge valves are now open); g. When tank pressure drops to 15 kPa, the control system will open die tank vent valve 52; h. Control system will close both discharge valves and the boost valve 42, and open the manifold purge valve 72; i. Once all pressure sensors read zero pressure a 30 second timer will start, once timed out, control system will close all valves.

[0061] In the event that a blockage should occur in the discharge line, pressure recorded by the discharge transducer will approach and reach the same as the tank pressure recorded by the tank transducer, then the control system will close the applicable discharge valve and open the boost valve.

[0062] Referring now to Figures 3 through 6, where there is illustrated a silo 100. Those parts and control aspects of the silo which are identical (or near-identical) to corresponding parts and control aspects of the tanker 1 of Figures 1 and 2, will be denoted by the same reference numerals and will not be described again in detail.

[0063] The silo 100 differs principally in the following respects:

a. It is larger and comprises a single internal compartment, hopper 6, discharge valve, and discharge line pressure sensor; b. It is equipped with pipework to discharge from both sides thereof; c. It comprises three aeration valves 32 at each end thereof; d. It is provided with a series of support retractable legs 110 at various positions along its length, upon which it can be stood; e. Each of the legs 1 10 comprises a load cell, via which the overall weight of the silo 100 and its load can be determined; f. The control system further comprises an overfill prevention feature which prevents overfilling of the silo, by shutting off inflow in response to sensing a predetermined load via the load cells.

[0064] Advantageously then, the unloading system for a container for a particulate material disclosed herein, is able to control unloading of the product, and control and maintain material flow in the discharge line, thus preventing blockages in the discharge line, without intervention from an operator.

[0065] A user/operator may define a volume of the particulate material for unloading from the container and set a rate of unloading, whereby both the defined volume and the rate of unloading may be set via the control system. The control system monitors the discharge line pressure continuously during unloading and controls the boost valve in response via the feedback loop, adjusting the boost valve position in response to advantageously maintain the set rate until the volume of the particulate material is unloaded. In this way, by way of example, the user/operator may define a 50,000 kg volume of particulate material to be unloaded from the container and set a rate of 800 kg per minute to be unloaded via the control system, which monitors the discharge line pressure continuously to maintain the rate of 800 kg per minute until the total volume of 50,000 kg particulate material is unloaded.

[0066] Throughout the specification and the claims that follow, unless the context requires otherwise, the words“comprise” and“include” and variations such as“comprising” and“including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[0067] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

[0068] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.

Claims (35)

1. A system for unloading a particulate material from a container (unloading system), the unloading system comprising a discharge system for carrying away the material from one or more compartments to a container outlet, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at a material outlet for each compartment to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

2. The unloading system of claim 1 , wherein in use, if the discharge line pressure increases beyond a set range, then the control system will open the boost valve further in response.

3. The unloading system as in either of claims 1 or 2, wherein in use, if the discharge line pressure decreases beyond a set range, then the control system will close the boost valve somewhat in response.

4. The unloading system as in any one of the preceding claims, wherein the control system further comprises a pressure sensor for each compartment, and in response to a sensed compartment pressure and the sensed discharge line pressure continuously coordinating operation of the or each discharge valve and the boost valve via a feedback loop, to control and maintain material flow in the discharge line.

5. The unloading system of claim 4, wherein in use, if the discharge line pressure reaches or approaches the compartment pressure, then the control system will close the discharge valve for that compartment and open the boost valve further.

6. The unloading system as in any one of the preceding claims, further comprising a gas pressurisation system for pressurising a compartment or each of a plurality of compartments contained within the container, and wherein the control system coordinates operation of the gas pressurisation system and the discharge system to effect unloading.

7. A container for a particulate material, the container comprising at least one storage compartment, the or each compartment comprising a hatch for access thereto, a discharge hopper, a lowermost material outlet, the container further comprising a system for unloading the particulate material from the container (unloading system), the unloading system comprising a discharge system for carrying away the material from the or each compartment, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at the or each material outlet to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use, the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

8. The container of claim 7, wherein in use, if the discharge line pressure increases beyond a set range, then the control system will open the boost valve further.

9. The container as in either of claims 7 or 8, wherein in use, if the discharge line pressure decreases beyond a set range, then the control system will close the boost valve somewhat.

10. The container as in any one of claims 7 through 9, wherein the control system further comprises a pressure sensor for each compartment, and in response to a sensed compartment pressure and the sensed discharge line pressure continuously coordinating operation of the or each discharge valve and the boost valve via a feedback loop, to control and maintain material flow in the discharge line.

11. The container of claim 10, wherein in use, if the discharge line pressure reaches or approaches the compartment pressure, then the control system will close the discharge valve for that compartment and open the boost valve further.

12. The container as in any one of claims 7 through 11 , further comprising a gas pressurisation system for pressurising a compartment or each of a plurality of compartments contained within the container, and wherein the control system coordinates operation of the gas pressurisation system and the discharge system to effect unloading.

13. The container as in any one of claims 7 through 12, wherein there is for each compartment a discharge line pressure sensor adjacent to the respective discharge valve, and wherein in use the control system monitors the discharge line pressure sensor associated with the compartment being emptied at the time.

14. The container as in any one of claims 7 through 13, further comprising a container vent valve under the control of the control system.

15. The container as in any one of claims 7 through 14, wherein there is for each compartment a particulate aerator under the control of the control system.

16. The container as in any one of claims 7 through 15, wherein the container is trailer-mounted, so as to be transportable.

17. The container as in any one of claims 7 through 16, wherein the container comprises a silo.

18. A pneumatic tanker for a particulate material, the tanker comprising at least one storage compartment, the or each compartment comprising a hatch for access thereto, a discharge hopper, a lowermost material outlet, and a system for unloading the particulate material from the container (unloading system), the unloading system comprising a discharge system for carrying away the material from the or each compartment, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at the or each material outlet to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

19. The pneumatic tanker of claim 18, wherein in use, if the discharge line pressure increases beyond a set range, then the control system will open the boost valve further.

20. The pneumatic tanker as in either of claims 18 or 19, wherein in use, if the discharge line pressure decreases beyond a set range, then the control system will close the boost valve somewhat.

21. The pneumatic tanker as in any one of claims 18 through 20, wherein the control system further comprises a pressure sensor for each compartment, and in response to a sensed compartment pressure and the sensed discharge line pressure continuously coordinating operation of the or each discharge valve and the boost valve via a feedback loop, to control and maintain material flow in the discharge line.

22. The pneumatic tanker of claim 21, wherein in use, if the discharge line pressure reaches or approaches the compartment pressure, then the control system will close the discharge valve for that compartment and open the boost valve further.

23. The container as in any one of claims 18 through 22, further comprising a gas pressurisation system for pressurising a compartment or each of a plurality of compartments contained within the container, and wherein the control system coordinates operation of the gas pressurisation system and the discharge system to effect unloading.

24. The container as in any one of claims 18 through 23, wherein there is for each compartment a discharge line pressure sensor adjacent to the respective discharge valve, and wherein in use the control system monitors the discharge line pressure sensor associated with the compartment being emptied at the time.

25. The container as in any one of claims 18 through 24, further comprising a container vent valve under the control of the control system.

26. The container as in any one of claims 18 through 25, wherein there is for each compartment a particulate aerator under the control of the control system.

27. A silo for a particulate material, the silo comprising at least one storage compartment, the or each compartment comprising a hatch for access thereto, a discharge hopper, a lowermost material outlet, and a system for unloading the particulate material from the container (unloading system), the unloading system comprising a discharge system for carrying away the material from the or each compartment, and a control system for controlling operation of the unloading system, the discharge system comprising a discharge valve positioned at the or each material outlet to control the discharge of material from the compartment into a discharge line, the unloading system comprising a boost line extending from a pressure feed line to the discharge line, and comprising a boost valve, the boost valve being adjustable to any desired position at or between fully open and fully closed, and adapted to provide position feedback to the control system, the control system comprising at least one pressure sensor for the discharge line, and wherein in use the control system will monitor discharge line pressure continuously and control the boost valve in response via a feedback loop, adjusting boost valve position in response to discharge line pressure to maintain material flow in the discharge line.

28. The silo of claim 27, wherein in use, if the discharge line pressure increases beyond a set range, then the control system will open the boost valve further.

29. The silo as in either of claims 27 or 28, wherein in use, if the discharge line pressure decreases beyond a set range, then the control system will close the boost valve somewhat.

30. The silo as in any one of claims 27 through 29, wherein the control system further comprises a pressure sensor for each compartment, and in response to a sensed compartment pressure and the sensed discharge line pressure continuously coordinating operation of the or each discharge valve and the boost valve via a feedback loop, to control and maintain material flow in the discharge line.

31. The silo of claim 30, wherein in use, if the discharge line pressure reaches or approaches the compartment pressure, then the control system will close the discharge valve for that compartment and open the boost valve further.

32. The silo as in any one of claims 27 through 31 , further comprising a gas pressurisation system for pressurising a compartment or each of a plurality of compartments contained within the container, and wherein the control system coordinates operation of the gas pressurisation system and the discharge system to effect unloading.

33. The silo as in any one of claims 27 through 32, wherein there is for each compartment a discharge line pressure sensor adjacent to the respective discharge valve, and wherein in use the control system monitors the discharge line pressure sensor associated with the compartment being emptied at the time.

34. The silo as in any one of claims 27 through 33, further comprising a container vent valve under the control of the control system.

35. The silo as in any one of claims 27 through 34, wherein there is for each compartment a particulate aerator under the control of the control system.