AU674434B2

AU674434B2 - Pneumatic bulk pressure vessel

Info

Publication number: AU674434B2
Application number: AU73066/94A
Authority: AU
Inventors: Robert Fairweather
Original assignee: Convair Engineering Pty Ltd
Current assignee: Convair Engineering Pty Ltd
Priority date: 1993-11-05
Filing date: 1994-09-19
Publication date: 1996-12-19
Anticipated expiration: 2014-09-19
Also published as: AU7306694A

Description

674434

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicants: CONVAIR ENGINEERING PTY LTD A.C.N. 058 868 134 Invention Title: PNEUMATIC BULK PRESSURE VESSEL o a 0* 4 44**4 The following statement is a full description of this invention, including the best method of performing it known to us: PNEUMATIC BULK PRESSURE VESSEL This invention relates to a pneumatic bulk pressure vessel for transporting and transferring dry powder or granulated material under pressure to another storage vessel, such as a silo.

Such pressure vessels are mounted on a chassis of a vehicle so that material can be transported from one place to another. The vessels have multiple outlets formed at the bottom of discharge cones and have a void between the discharge cones. The void is partly formed by shedder plates whose function is to shed material down towards the discharge cones when the vessel is being emptied. The shedder plates can be either pressure bearing or nonpressure bearing. In order to decrease the weight of pressure vessels it is conventional to provide shedder plates which are non-pressure bearing and which are therefore formed from lighter material than pressure bearing shedder plates. Whilst non-pressure bearing shedder plates do decrease the weight of the pressure 20 vessel it is necessary to equalise the pressure across the non-pressure bearing shedder plates to prevent them from buckling when the vessel is pressurised.

Conventional bulk vessels are pressurised by passing air through aeration devices to maintain the material in the pressure vessel in a fluid state and also to facilitate discharge of the material from the discharge *cones. As the shedder plates are non-pressure bearing air must be allowed to flow into the void as the vessel is being pressurised so that the pressure is balanced across the shedder plates. In order to provide pressurised air to the void an internal venting duct is provided in the vessel which communicates with the void so that air flows from the vessel through the duct and into the void. A filter is fitted onto the venting duct to minimise dust and overflow of product into the void. When the vessel is empty, pressure drops in the vessel and air flows from the void, stalllennaokeepWPROV CONVAIR SHW 199 through the duct and filter, into the vessel in order to maintain equal pressure on both sides of the shedder plates.

The requirement for filters to minimise dust and overflow of product into the void creates a difficulty when the vessel is to be cleaned. Cleaning of the vessel is necessary when the product carried by the vessel is to be changed and cleaning normally takes place by merely washing out the vessel with water. Unless the filters are removed, which is a difficult and time consuming task, the filters can be damaged or blocked by the combination of water and material during a washing operation.

The object of the present invention is to provide a pneumatic bulk vessel which overcomes the above problems.

The invention may be said to reside in a pneumatic bulk vessel including; a vessel body defining a material storage space and having at least one discharge cone; a void arranged adjacent the discharge cone; 20 a non-pressure bearing shedder plate forming a barrier between the void and the discharge cone; a first air inlet in the pressure vessel for providing pressurised air to the material storage space; a second air inlet in the void for providing to 25 pressurised air to the void, the second air inlet being external to the storage space; an outlet communicating the void with the storage space; and control means for allowing flow of air from the void to the storage space and preventing flow of air from the storage space to the void.

Since the void is provided with the second air inlet, pressurised air is provided directly to the void from the exterior of the storage space so that the pressure in the void and the vessel and therefore across the nonpressure bearing shedder plate can be equalised. The lalltennekeepPROV CONVAIR SHW 199 control means controls the flow of air out of the void so that during pressurisation and when the pressure drops in the pressure vessel when the vessel is empty or being emptied air is also able out of the void to maintain equal pressure across the shedder plate. Thus, air flow is always from the void to the storage space and therefore there is no need to provide filters or the like to prevent dust or material from entering the void. Thus, cleaning can take place without the need to remove filters.

Preferably the second air inlet includes a check valve for limiting air flow into the void.

Preferably the first inlet to the storage space and the second inlet to the void are coupled to a common inlet manifold and preferably the check valve is a spring loaded check valve which is set to provide a back pressure such as air will flow through the first inlet as well as into the void.

Preferably the storage space includes at least S: two discharge cones with the void being arranged between the discharge cones, the void being defined by a bottom wall and a pair of shedder plates each of which forms a wall between the void and a respective one of the discharge cones.

Preferably a pair of first inlets is provided to 25 each of the discharge cones and each of the discharge cones includes at least one aeration device for aerating material in the pressure vessel and pressurising the pressure vessel.

Preferably the outlet comprises a venting duct within the storage vessel and the control means comprises a swing check valve to allow the free escape of air from the void via the venting duct into the storage space and which prevents ingress of air from the storage space to the duct and the void.

A preferred embodiment of the invention will be described, by way of example, with reference to ,Iitelnno.kOp-PPOV C(NVAIR SHW 199 accompanying drawing Figure 1 which shows a cross-sectional view of a pressure vessel embodying the invention.

With reference to Figure 1 a pressure vessel is shown which is intended to be arranged on a chassis of a vehicle (not shown) so that material can be transported in the pressure vessel. The pressure vessel 10 has a vessel body 11 which defines a storage space 13 and includes discharge cones 12 and 14. A void 16 is arranged between the discharge cones 12 and 14. The void 16 is defined by a bottom wall 18 and a pair of non-pressure bearing shedder plates 20 which define a barrier between the discharge cones 12 and 14 and the void 16.

An air inlet manifold 22 is provided for providing air to first air inlets 24 which are connected to aeration devices 26 in the discharge cones 12 and 14 for providing pressurised air to the storage space 13 and also for aerating material in the storage space 13. A second air inlet 28 is also coupled to the manifold 22 and a S' communicates with the void 16 externally of the storage 20 space 13. In the embodiment shown the second air inlet 28 is outside the vessel body 11. However, in other embodiments the inlet 28 could be a pipe or hose which passes through the storage space 13 but which does not communicate with the storage space 13. The requirement for 25 the second air inlet 28 to be external of the storage space merely requires air to be provided from a source other than the storage space itself.

The inlet 28 is provided with a spring loaded check valve 30. A venting duct 32 is provided in the storage space 13 and communicates the void 16 with the storage space 13. A swing checked valve 34 controls flow of air from the duct 32 into the storage space 13.

Air flow from the manifold 22 to the inlets 24 provides pressurised air to the aeration devices 26 which both pressurises the storage space 13 of the vessel and aerates material in the vessel. Air flow into the void 16 staffennekkepPPlOV CONVAIR SHW 99 through the inlet 29 also pressurises the void 16 so that the pressure across the non-pressure bearing shedder plates is equalised. The spring loaded check valve 30 is set to provide a back pressure such that air will flow through the aeration devices 26 as well as into the void 16. The spring loading of the check valve 30 ensures that there is a restriction in the second inlet 28 to ensure that air does flow through the first inlets 24 to the aeration devices 26.

Air in the void 16 is able to pass through the vent 32 and the swing check valve 34 into the storage space 13 so that pressure in the void and storage space is equalised to thereby equalise the pressure across the shedder plates 20. However, the swing check valve 34 prevents air flow in the opposite direction from the storage space 13 into the vent 32 and therefore the void 16. During emptying of the pressure vessel 10 air is able to flow freely out of the void 16 through the check valve 34 into the storage space 13 thus maintaining the pressure 20 equ lisation across the shedder plates 20. Thus, the swing check valve 34 allows air flow only from the void 16 to the storage space 13 and does not allow air flow from the storage space back into the void. Therefore filters and the like are not required in order to eliminate dust and overflow of product into the void because the void is pressurised from the second inlet external to the pressure vessel The first inlets 24 may be provided with control valves (not shown). If one of the control valves to one of the aeration devices is restricted in order to achieve more fluidisation to other aeration devices, the flow rate through the spring loaded check valve 30 will increase causing an increased restriction. The pressure available to the operating aerators will therefore increase.

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled stAllonne;keepFPROV CONVAIR SHW 19g within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.

*e *0 C

C

C.

C

C. C C. C

C

C C C. C C C at,,itennoikoepiPRIOV CONVAtRHW W9

Claims

1. A pneumatic bulk vessel including; a vessel body defining a material storage space and having at least one discharge cone; a void arranged adjacent the discharge cone; a non-pressure bearing shedder plate forming a barrier between the void and the discharge cone; a first air inlet in the pressure vessel for providing pressurised air to the material storage space; a second air inlet in the void for providing pressurised air to the void, the second air inlet being external to the storage space; an outlet communicating the void with the storage space; and control means for allowing flow of air from the void to the storage space and preventing flow of air from the storage space to the void.

2. The vessel of Claim 1 wherein the second air 9* inlet includes a check valve for limiting air flow into the void.

3. The vessel of Claim 1 or Claim 2 wherein the first inlet to the storage space and the second inlet to the void are coupled to a common inlet manifold and preferably the check valve is a spring loaded check valve 25 which is set to provide a back pressure such as air will flow through the first inlet as well as into the void.

4. The vessel accordinq to any one of the preceding claims wherein the storage space includes at least two discharge cones with the void being arranged between the discharge cones, the void being defined by a bottom wall and a pair of shedder plates each of which forms a wall between the void and a respective one of the discharge cones.

The vessel according to any one of the preceding claims wherein a pair of first inlets is provided to each of the discharge cones and each of the discharge cones tcitflnneokoopiPrOV CONVAIR 451W 100 includes at least one aeration device for aerating material in the pressure vessel and pressurising the pressure vessel.

6. The vessel according to any one of the preceding claims the outlet comprises a venting duct within the storage vessel and the control means comprises a swing check valve to allow the free escape of air from the void via the venting duct into the storage space and which prevents ingress of air from the storage space to the duct and the void.

7. A pneumatic bvlk vessel substantially as hereinbefore described with reference to the accompanying drawings **0 4. 4 **4 *e *4 4 4e tMItonnopP$UV CONVAIR SHW I19 ABSTRACT A pneumatic bulk vessel is disclosed which has a body (11) defining a storage space The body (11) has a pair of cones (12) and (14) for discharge of material. A void (16) is arranged between discharge cones (12) and An inlet (24) is provided for providing pressurised air to the storage space (13) and a second inlet (28) is provided for providing pressurised air to the void A venting duct (32) is provided in the storage space (13) and communicates with the void (16) and a check valve (34) is provided in the duct (32) for allowing air to flow from the duct (32) into the storage space (13) but preventing air from flowing back from the storage spaced (13) into the duct (32). *oo Soo9 9**9 at f f ft 9 ft 9t S 4 btIA rwnnokooep PA)V ('(NVAIP £RW tUo