GB1572003A

GB1572003A - Pneumatic suction conveying plant

Info

Publication number: GB1572003A
Application number: GB13181/77A
Authority: GB
Original assignee: ZIMMERMANN AZO MASCHF
Current assignee: ZIMMERMANN AZO MASCHF
Priority date: 1976-04-06
Filing date: 1977-03-29
Publication date: 1980-07-23
Also published as: DK141684B; JPS52123085A; DE2614713B2; DE2614713C3; FR2347289A1; NL7702154A; FR2347289B1; DK141684C; SE7703510L; DK150977A; DE2614713A1

Description

(54) PNEUMATIC SUCTION CONVEYING PLANT (71) We, AZO-MACHINEN FABRIK ADOLF ZIMMER MANN GMBH. a German Company, of D-6960 Osterburken, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to pneumatic suction conveying plant for supplying a plurality of consumers with particulate material from at least one storage container.

In a known plant of this kind (DE-OS 2,136,328) the pneumatic conveying line leads axially and vertically into the product chamber of a separator having a product chamber and a clean air chamber. Between the delivery pipe of the conveying line and the wall of the separator a filter is held in a slack condition. Upon charging from the supply container, that is to say when there is a depression in the clean air chamber, the filter bulges into the clean air chamber. The material arriving through the delivery pipe of the conveying line is separated in its gravity descent. whilst the conveying air passes into the suction line through the filter. The filter is so designed that all the solid particles are separated from the conveying stream.

Such suction conveying plants are used, for example, in the synthetic plastics processing industry for supplying a plurality of processing machines from one or more silos containing, for example. a synthetic plastics granulate. In the processing of synthetic plastics material it is possible for dust contained in the granulate to impair the mechanical and optical properties of the end product.

The present invention takes as its basic purpose the provision of a suction conveying plant which can be so designed that dustfree material will be delivered to the consumer.

According to the invention there is provided a suction conveying plant as defined in claim 1 of the appended claims.

With this arrangement of a separate dust separator before the blower the result can be achieved, by giving the filter in each particulate material separator a mesh dimension which is only slightly smaller than the smallest grain size of the material required by the consumer, that any dust contained originally in the particulate material, or perhaps created during conveyance, is not retained by the filters in the separators. On the contrary the dust passes through these filters and is only separated immediately in front of the blower. On the other hand the particulate material precipitating at the separator is absolutely free of dust.As contrasted with known plants, the construction of the suction conveying plant according to the invention has the further advantage that the filter resistance in the individual separators is materially reduced, and that it is only necessary to have a single dust separator with a suitably high filter resistance for all of the separators. Not only is an improvement in the technical functioning of the plant achieved thereby, but a reduction in cost is also possible.

In a preferred construction according to the invention the filter in each separator is so designed that its flow cross-section (i.e.

its open area, that is the total area of the apertures therein) is substantially greater than the free cross-section of the suction line. The filter resistance is therefore not greater than the resistance of the line, and consequently there is an unrestricted flow through the filter, which entrains the dust particles.

The filter arranged upstream of the suction connection of the blower is advantageously designed as a conventional battery of pocket-type filters, which is distinguished by its high degree of separation. By the design of the plant in accordance with the invention its efficiency is materially improved.

The invention will now be described, by way of example. with reference to the accompanying drawing, the single Figure of which shows a practical form of the invention as a flow diagram.

In the drawing there are shown three supply hoppers 1, 2 and 3 belonging to storage containers not shown. To each of these supply hoppers 1, 2 and 3 there is connected a pneumatic conveying line 4, which is taken to a plurality of consumers in the present example three consumers not shown in the drawing. To each consumer there is allocated a delivery hopper 5, upstream of each of which is a separator 6.

The suction conveying plant furthermore includes a suction blower 7, to which each separator 6 is connected through a suction line 8 and a branch line 9.

Each separator 6, and therefore each consumer, can be connected when necessary to any of the three conveying lines 4, and therefore to any of the three supply hoppers 1, 2 and 3 for the purpose of conveying into the separators 6 various products, for example. which are stored in the various storage containers. Thus, the separator 6 shown at the left hand side of the drawing is shown connected to the Iower supply hopper 3, the centre separator is shown connected to the upper supply hopper 1 and the separator at the right hand side is shown connected to the middle supply hopper 2.In the operating condition shown in the drawing the right hand consumer is being supplied with particulate material, the flap 10 being closed at the exit of the separator 6 and the three valves in the valve block VB (shown diagrammatically) being set as shown to open the connection between the clean air chamber 13 and the suction branch line 9, to open the connection between the product chamber 12 and a branch line 11 mentioned below, and to close a ventilation opening to the atmosphere. On the other hand the flaps 10 of the two other separators are open, so that the product enters the delivery hoppers 5 of the consumers.

The separators 6 are in communication with the conveying lines 4 through respective branch lines 11. For the sake of clarity the drawing has been simplified by omitting two of the branch lines 11 to each separator 6 from the stub pipes shown in the other two conveying lines 4. The branch lines 11 lead in each case into the lower chamber. namely the product chamber 12 of the separator. By means of a filter 14, the product chamber 12 is separated from the clean air chamber 13 connected to the branch line 9 of the suction line 8, the filter having a relatively large mesh dimension. The mesh dimension is so selected that the particles of the material having the smallest grain size which is desired for the processing are retained and therefore fall into the product chamber 12 and can be transferred into the delivery hopper 5.All smaller particles, in particular dust, pass through the filter 14 and travel through the branch line 9 and the suction line 8 to the blower 7.

Upstream of the blower 7, in fact upstream of its suction pipe 15, there is arranged a separator 16 having a plurality of pocket-type filters 17, through which the clean air flows from the outside. The mesh dimension is so selected that the pockettype filters 17 retain any dust still present in the clean air. Consequently, only a single dust separator is necessary for all of the consumers, whilst the filters 14 for the individual separators retain no dust and moreover have a flow cross-section (as hereinbefore defined) which is equal to or greater than the free or conveying crosssection of the suction line 8, including the branch lines 9.

WHAT WE CLAIM IS: 1. A pneumatic suction conveying plant for supplying a plurality of consumers with particulate material from at least one storage container; said plant comprising at least one storage container for such material, a plurality of consumers, a pneumatic conveying line or respective pneumatic conveying lines between the storage container or the respective storage containers and the consumers, respective separators situated above the respective consumers for separating said material from conveying air, and a suction line connected to each of the separators and to a blower for causing the conveying air to flow by suction, wherein each of the separators includes a product chamber and a clean air chamber, the product chamber being connected to the pneumatic conveying line, or to at least one such line where the plant has a plurality of such lines, and being arranged for discharging material accumulated therein to the consumer, the clean air chamber being connected to the suction line, and said chambers being separated from each other by a filter for separating the particulate material from its conveying air, and a finer mesh filter for separating the dust contained in the stream of clean air from the separators is provided in the suction line downstream of the clean air chambers and upstream of the suction connection of the blower.

2. A suction conveying plant according to claim 1 wherein the filter in each of the separators has a flow cross-section (as hereinbefore defined) substantially greater than the free cross-section of the suction

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. by its high degree of separation. By the design of the plant in accordance with the invention its efficiency is materially improved. The invention will now be described, by way of example. with reference to the accompanying drawing, the single Figure of which shows a practical form of the invention as a flow diagram. In the drawing there are shown three supply hoppers 1, 2 and 3 belonging to storage containers not shown. To each of these supply hoppers 1, 2 and 3 there is connected a pneumatic conveying line 4, which is taken to a plurality of consumers in the present example three consumers not shown in the drawing. To each consumer there is allocated a delivery hopper 5, upstream of each of which is a separator 6. The suction conveying plant furthermore includes a suction blower 7, to which each separator 6 is connected through a suction line 8 and a branch line 9. Each separator 6, and therefore each consumer, can be connected when necessary to any of the three conveying lines 4, and therefore to any of the three supply hoppers 1, 2 and 3 for the purpose of conveying into the separators 6 various products, for example. which are stored in the various storage containers. Thus, the separator 6 shown at the left hand side of the drawing is shown connected to the Iower supply hopper 3, the centre separator is shown connected to the upper supply hopper 1 and the separator at the right hand side is shown connected to the middle supply hopper 2.In the operating condition shown in the drawing the right hand consumer is being supplied with particulate material, the flap 10 being closed at the exit of the separator 6 and the three valves in the valve block VB (shown diagrammatically) being set as shown to open the connection between the clean air chamber 13 and the suction branch line 9, to open the connection between the product chamber 12 and a branch line 11 mentioned below, and to close a ventilation opening to the atmosphere. On the other hand the flaps 10 of the two other separators are open, so that the product enters the delivery hoppers 5 of the consumers. The separators 6 are in communication with the conveying lines 4 through respective branch lines 11. For the sake of clarity the drawing has been simplified by omitting two of the branch lines 11 to each separator 6 from the stub pipes shown in the other two conveying lines 4. The branch lines 11 lead in each case into the lower chamber. namely the product chamber 12 of the separator. By means of a filter 14, the product chamber 12 is separated from the clean air chamber 13 connected to the branch line 9 of the suction line 8, the filter having a relatively large mesh dimension. The mesh dimension is so selected that the particles of the material having the smallest grain size which is desired for the processing are retained and therefore fall into the product chamber 12 and can be transferred into the delivery hopper 5.All smaller particles, in particular dust, pass through the filter 14 and travel through the branch line 9 and the suction line 8 to the blower 7. Upstream of the blower 7, in fact upstream of its suction pipe 15, there is arranged a separator 16 having a plurality of pocket-type filters 17, through which the clean air flows from the outside. The mesh dimension is so selected that the pockettype filters 17 retain any dust still present in the clean air. Consequently, only a single dust separator is necessary for all of the consumers, whilst the filters 14 for the individual separators retain no dust and moreover have a flow cross-section (as hereinbefore defined) which is equal to or greater than the free or conveying crosssection of the suction line 8, including the branch lines 9. WHAT WE CLAIM IS:

1. A pneumatic suction conveying plant for supplying a plurality of consumers with particulate material from at least one storage container; said plant comprising at least one storage container for such material, a plurality of consumers, a pneumatic conveying line or respective pneumatic conveying lines between the storage container or the respective storage containers and the consumers, respective separators situated above the respective consumers for separating said material from conveying air, and a suction line connected to each of the separators and to a blower for causing the conveying air to flow by suction, wherein each of the separators includes a product chamber and a clean air chamber, the product chamber being connected to the pneumatic conveying line, or to at least one such line where the plant has a plurality of such lines, and being arranged for discharging material accumulated therein to the consumer, the clean air chamber being connected to the suction line, and said chambers being separated from each other by a filter for separating the particulate material from its conveying air, and a finer mesh filter for separating the dust contained in the stream of clean air from the separators is provided in the suction line downstream of the clean air chambers and upstream of the suction connection of the blower.

line.

3. A suction conveying plant according to claim 1 or claim 2, wherein the finer mesh filter comprises a battery of pocket-type filters.

4. A pneumatic suction conveying plant substantially as herein described with reference to the accompanying drawling.

5. A particulate material processing installation including a pneumatic suction conveying plant according to any one of the preceding claims.