Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G53/00—Conveying materials in bulk through troughs, pipes or tubes by floating the materials or by flow of gas, liquid or foam
  • B65G53/34—Details
  • B65G53/60—Devices for separating the materials from propellant gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G53/00—Conveying materials in bulk through troughs, pipes or tubes by floating the materials or by flow of gas, liquid or foam
  • B65G53/04—Conveying materials in bulk pneumatically through pipes or tubes; Air slides
  • B65G53/06—Gas pressure systems operating without fluidisation of the materials
  • B65G53/10—Gas pressure systems operating without fluidisation of the materials with pneumatic injection of the materials by the propelling gas
  • B65G53/14—Gas pressure systems operating without fluidisation of the materials with pneumatic injection of the materials by the propelling gas the gas flow inducing feed of the materials by suction effect
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G53/00—Conveying materials in bulk through troughs, pipes or tubes by floating the materials or by flow of gas, liquid or foam
  • B65G53/04—Conveying materials in bulk pneumatically through pipes or tubes; Air slides
  • B65G53/24—Gas suction systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G53/00—Conveying materials in bulk through troughs, pipes or tubes by floating the materials or by flow of gas, liquid or foam
  • B65G53/04—Conveying materials in bulk pneumatically through pipes or tubes; Air slides
  • B65G53/28—Systems utilising a combination of gas pressure and suction

Definitions

• the invention relates to a device and a method for the pneumatic conveying of powdery substances with a container using at least one filter in pipe systems.
• the invention also covers the use of this device and / or this method.
• EP-A-0 574 596 describes a system for the pneumatic handling of cement from ships in silos by means of a so-called lock container made of several container segments; There is an exhaust air filter in the top tank segment, the bottom tank segment tapers like a funnel.
• Powdery substances are also conveyed and transported in a controlled atmosphere in the chemical, pharmaceutical and food industries.
• the known systems for conveying powdery materials of this type are mostly matched in their construction to the product to be conveyed subsequently; these systems are one-offs that require high investment costs.
• Another disadvantage of the known systems is that the filters required clog after a short period of operation. As a result of this problem, faults often occur in the production of the powdery substances, which lead to costly production downtimes. To date, these deficiencies have not been remedied. Pouring powder into reaction vessels or reactors within explosive zones is generally done manually using a lock or a protective valve, since most reactors do not have the necessary space for an adequate loading system.
• the ratio of the length of the container forming a pump chamber is circular in the case of the above-mentioned device for the pneumatic conveying of powdery substances with a specific weight of 0.1 to 15, g / cm 3 and with a grain size range between 0.1 and 300 ⁇ m as the conveyed material. or also polygonal cross-section for temporarily receiving the conveyed material to its inner diameter greater than 0.5; in addition, the width of the filter provided between a vacuum pump for sucking the conveyed material and the container should at most correspond to the cross section determined by the container diameter.
• the blocking element of the supply line opens during a suction phase, whereas the discharge line remains closed. Thanks to the open vacuum connection, material to be conveyed is sucked into the pump chamber; after a predetermined period of time, the feed line closes and the discharge is released. The material to be conveyed is expelled by pressure - compressed air or nitrogen for filter cleaning.
• the filter in the upper part of the container retains the finest particles and cleans itself with every emptying cycle.
• a ratio of container length to container diameter in the range between 0.5 and 10.0 - preferably between 2.0 and 8.0 - has proven to be favorable.
• the container width or the container diameter itself is advantageously between 10 and 500 mm, in particular 50 and 400 mm, the container length between 200 and 1000 mm, in particular between 400 and 900 mm. It is therefore a comparatively narrow container, the diameter of the container preferably determining the filter size.
• the device it is within the scope of the invention to drive the device with a vacuum for sucking in the conveyed material between 1 and 25 mbar - especially 5.0 to 20 mbar.
• the overpressure to discharge the material to be conveyed should be between 0.5 and 5.0 bar - in particular 1.0 and 3.0 bar.
• the filter is to be designed in such a way that a differential pressure between 100 and 300 mbar is produced on its side facing away from the vacuum pump.
• a flat grid has also proven to be advantageous, which is assigned to the filter on the vacuum side as a support device. Its preferred mesh size should be between 5 and 50 mm, preferably between 10 and 40 mm. A grid can also be provided on the other filter surface. In addition, that grating can be connected to a vibration drive and can thus be designed as a vibration source for the filter.
• the filter is assigned a countercurrent rinse according to the invention during emptying, which can be controlled at time intervals; such an air jet can be provided on both filter surfaces.
• a reactive gas or an inert gas is preferably used to discharge the pulverulent substances by pneumatic conveying
• the system described enables powdery products to be conveyed through a flat filter membrane installed in the upper part of a pumping chamber; the diameter of which corresponds to that of the filter membrane. Powder products are conveyed by alternately applying a vacuum and pressure source to the pump chamber.
• the vacuum generated by a vacuum pump sucks the powdery material into the pumping chamber, the filter separates particles sucked in by the vacuum pump from the air.
• the pressure of the conveying gas enables the pumping chamber to be emptied and, at the same time, the filter to be cleaned by a counterflow.
• the system considerably reduces the risk of explosion during the introduction of powders into reactors or similar vessels that contain flammable gases / vapors. Since powder is conveyed by suction, the risk of explosion in the delivery line is considerably reduced. The powder / oxygen ratio is in most cases outside the explosion limit. Since none rotatable parts are present, also any kind of ignition, explosion risk due to friction.
• This technology enables powder from sacks, big bags or silos to be filled into a pressurized container and thus fully meets the expectations regarding safety precautions in the chemical and pharmaceutical industries.
• gases e.g. Nitrogen, argon.
• the use of a neutral gas for emptying makes it possible, for example, to fill inertized reactors with powder without introducing oxygen into the reactor.
• the consumption of inert gas is low because it is not used for powder delivery during the suction phase, but only for emptying the pump chamber.
• the oxygen is separated from the powder and replaced by inert gas.
• the volume of the chamber of conventional systems is large because of the large volume of the filter. These systems are emptied gravimetrically.
• a reducer is usually required to allow the system to be connected to a standard size flange. The reduction often triggers operational problems and requires the use of a vibrator or the like.
• Auxiliary device to discharge the powder from the separator. The device or method described is preferably used according to the invention in the chemical industry or the food industry, in the pharmaceutical industry or in the industry producing paints and varnishes.
• FIG. 2 an enlarged detail from FIG. 1;
• FIG. 3 shows a side view of a tension lock of the device
• Fig. 7 the top view of the device of Fig. 4;
• Fig. 8 a partial oblique view of a filter insert.
• a device 10 for the pneumatic conveying of powdery substances with a specific weight of 0.1 to 15.0 g / cm 3 in a grain size range between 0.1 and 300 ⁇ m from a silo 9 indicated in FIG. 5 to a reaction vessel or reactor 11 has a cylindrical container 12 - made of electrolytically polished stainless steel - with a length a of here 600 or 850 mm, the interior of which has an inner diameter d of 200 or 300 mm as the pump chamber 13, as well as a connecting piece 14 a for a feed line 14 for suction of the conveyed material.
• the Feed line 14 contains a so-called butterfly valve 16 as a blocking element in a connecting flange 15.
• a valve housing 20 and a drive member 21 for a butterfly valve 16 are a discharge line 22 a indicated.
• a directed hook members 19 of the container bottom 18 serve to its releasable fastening means of a clamping hook 23 to pull tabs 23 a having locking means 24 of the container 12 .
• the container 12 ends at a filter insert 26, which is spanned by a dome cover 30, provided axially with a T-shaped connecting pipe 28. This is fixed with a further locking device 24 a on the pull hook 32 of the container 12. Its upper section is surrounded in FIG. 1 - together with the described container cover 26, 30 - by a hood frame 34.
• the butterfly valve 16 of the feed line 14 opens, the discharge line 22 remains closed. Now the pump chamber 13 fills up to a desired filling level, possibly also completely, thanks to the build-up of a vacuum via the vacuum line 27 a . After a predetermined period of time, the feed line 14 is closed and the discharge line 22 is opened. The powder is expelled by means of pressure - for example nitrogen for filter cleaning - after opening the shut-off valve 17 in the conveying gas line 29 a . At the end of the suction phase, the vacuum line 27 a remains open for a certain time before the butterfly valve 16 a of the discharge line 22 is opened in order to remove the oxygen from the pump chamber 3.
• the filter in the filter insert 26 which retains the powder and at the same time maintains the suction capacity of the system. Thanks to its location between the pump chamber 13 and the conveying gas source 29, the filter is cleaned every cycle and therefore retains its full filtration capacity.
• the four locking elements 16, 16 a , 17, 27 are connected to one another at a control box 35 for control purposes.
• the butterfly valve 16 of the feed line 14 opens, whereas the discharge line 22 remains closed. Thanks to the open vacuum valve 16, the pump chamber 13 sucks up; after a predetermined period of time, the feed line 14 closes and the discharge line 22 is released.
• the material to be conveyed is expelled by pressure - compressed air or nitrogen for filter cleaning.
• the filter in the upper part of the container 12 retains the finest particles and cleans itself with every emptying cycle.
• the container 12 Before the powder is introduced into the downstream reactor 11, air and powder are separated from one another by closing the vacuum shut-off valve 16 against opening. of the conveying material inlet 14 is delayed. Thus 22 no gases of the reactor are aspirated 11 upon release of the discharge line, the container 12 is first pressurized and then the drain valve 16 is opened a. Otherwise, the vacuum line 27 a can only be opened when the discharge line 22 is closed.
• a suction phase of 10 to 12 seconds is preferred, and the emptying time will be of the order of 3 to 5 seconds:
• a pneumatically controlled throttling is provided. Usually one second is enough for this delay process.
• the closing of the vacuum for evacuating the air and the opening of the butterfly valve 16 a can be adapted to empty the powder.
• a maximum delay of one second should also suffice here.
• the pressure can be increased to 2.5 to 3 bar in order to achieve complete emptying and thorough filter cleaning.
• Fig. 6 two of the devices 10 are mounted in parallel next to one another on supports 36; their feed lines 14 open into a common outlet pipe 38 with a connecting flange 40 for a further delivery line neglected in the drawing. If the two devices 10 are operated alternately in the manner described, one can switch from a sequential system to a continuous one.
• a filter or a filter membrane 44 with a flat mesh 46 which is assigned on the vacuum side, is assigned in a ring frame 42 of the filter insert 26 as a support element.
• This can be connected to a vibration drive, not shown, and transmit its vibrations to the filter membrane 44.
• the latter is cleaned by an air jet - controlled at time intervals; several such air jets are also possible, which are directed onto both surfaces of the filter membrane 44.
• a wide-meshed bar grid 48 can additionally support this on the surface 45 facing away from that grid 46.
• the ratio of the length a to the diameter d of the container 12 is between 0.5 to 10, preferably 2 to 8; with these design specifications, at a pressure between 1 to 25 mbar - preferably 5 to 20 mbar - on the suction side and a pressure of 0.5 to 5 bar - preferably 1 to 3 bar - for ejecting the powder
• the problem-free conveyance of large quantities up to several tons per hour is possible.
• the described pump system or conveyor can also be dosed with a good accuracy of ⁇ 10%.
• Preferred dimensions of the container 12 for given operating parameters can be found in the table below:
• the suction body can be made of various materials such as stainless steel, plastic, Hastelloy or the like. exist to withstand the main chemical constraints.
• the system can also be connected to weighing systems in order to be able to precisely meter the powders directly into the reactors 11.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Air Transport Of Granular Materials (AREA)
• Nozzles (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

Priority Applications (7)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26030574

Family Applications (1)

Country Status (11)

Cited By (5)

Families Citing this family (60)

Citations (4)

Family Cites Families (19)

• 1997
  • 1997-10-21 AU AU51880/98A patent/AU5188098A/en not_active Abandoned
  • 1997-10-21 DE DE19746220A patent/DE19746220A1/de not_active Withdrawn
  • 1997-10-21 US US09/284,822 patent/US6325572B1/en not_active Expired - Lifetime
  • 1997-10-21 EP EP97946750A patent/EP0937004B2/de not_active Expired - Lifetime
  • 1997-10-21 DE DE59701540T patent/DE59701540D1/de not_active Expired - Lifetime
  • 1997-10-21 ES ES97946750T patent/ES2147999T5/es not_active Expired - Lifetime
  • 1997-10-21 CH CH02440/97A patent/CH689329A5/de not_active IP Right Cessation
  • 1997-10-21 AT AT97946750T patent/ATE192114T1/de active
  • 1997-10-21 CA CA002269626A patent/CA2269626C/en not_active Expired - Lifetime
  • 1997-10-21 CN CN97199061A patent/CN1075026C/zh not_active Expired - Lifetime
  • 1997-10-21 JP JP51895598A patent/JP4030589B2/ja not_active Expired - Lifetime
  • 1997-10-21 WO PCT/EP1997/005802 patent/WO1998017558A1/de not_active Ceased

Patent Citations (4)

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