Dust bag and method of production

• US 6,251,154 B1
• Filed: 10/06/1994
• Issued: 06/26/2001
• Est. Priority Date: 05/06/1992
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: van Rossen, Leonard M.
• Primary Examiner(s): JASTRZAB, KRISANNE MARIE
• Application Number:
  US08/318,645
• Time in Patent Office: 2,455 Days
• Field of Search: 553/82, 555/24, 55D/IG.2, 55D/IG.3, 55D/IG.5, 264/DIG.48, 264/145, 264/159, 264/160, 264/171.1, 156/199-203
• US Class Current: 55/382
• CPC Class Codes: A47L 9/14 Bags or the like; Rigid filtering receptacles; Attachment of, or closures for, bags or receptacles
• CPC Class Codes: B01D 39/163 sintered or bonded
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14
• CPC Class Codes: B31B 2155/00 Flexible containers made from webs
• CPC Class Codes: B31B 2170/00 Construction of flexible containers
• CPC Class Codes: B31B 2170/20 having multi-layered walls, e.g. laminated or lined
• CPC Class Codes: B31B 70/00 Making flexible containers, e.g. envelopes or bags
• CPC Class Codes: B31B 70/81 Forming or attaching accessories, e.g. opening devices, closures or tear strings
• CPC Class Codes: B32B 2323/10 Polypropylene
• CPC Class Codes: B32B 2439/06 Bags, sacks, sachets
• CPC Class Codes: B32B 5/022 Non-woven fabric
• CPC Class Codes: B32B 5/22 characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed layer formed of natural mineral fibres or particles next to a foam layer B32B19/047, next to a layer made of particles B32B19/048, or next to a fibrous or filamentary layer B32B19/06; paper layer or cardboard layer next to a paper layer or cardboard layer B32B29/005, next to a foam layer B32B29/007, next to a fibrous or filamentary layer B32B29/02, or next to a particulate layer B32B29/04
• CPC Class Codes: Y10S 264/48 Processes of making filters
• CPC Class Codes: Y10S 55/02 Vacuum cleaner bags
• CPC Class Codes: Y10S 55/03 Vacuum cleaner
• CPC Class Codes: Y10S 55/05 Methods of making filter
• CPC Class Codes: Y10T 156/1007 Running or continuous length work
• CPC Class Codes: Y10T 156/1008 Longitudinal bending
• CPC Class Codes: Y10T 156/101 Prior to or during assembly with additional lamina
• CPC Class Codes: Y10T 156/1011 Overedge bending or overedge folding
• CPC Class Codes: Y10T 156/1013 : and edge-joining of one piece blank to form tube

Abstract

A dust bag comprises a filter bag consisting of a filter material. In a first wall portion of the filter bag, an inlet opening is provided through which the air flow to be cleaned gets into the filter bag. On the inner surface of the wall portion opposite the inlet opening, there lies a protective layer of a resistant material of great tensile strength. This protective layer extends as a strip through the filter bag and prevents damage to the inner surface of the filter bag caused by particles striking the same.

Claims

1. A dust bag comprising:

a filter bag having an air-permeable filter material formed of synthetic thermoplastic fibers, said filter bag having two wall portions that are connected at longitudinally opposing edges so as to form said filter bag,

an inlet opening for allowing the air to be filtered to enter said filter bag, said inlet opening being provided in one of said wall portions, and

a protective layer of an air-permeable nonwoven web resistant to mechanical stresses caused by particles carried in an air flow and protecting said filter material, where the fibers forming the nonwoven web are interconnected at each intersection of the fibers and are thermoplastic, which protective layer is laid on the inner surface of the other of said wall portions without bonding to said wall portions and extending at least over the surface area thereof opposite said inlet opening between at least two interconnected edges of said wall portions between which said protective layer is held,

wherein said protective layer is in the form of a protective strip being narrower than the wall portions with longitudinal ends positioned and welded between at least the longitudinally opposing interconnected edges of said wall portions, said opposing edges defining the longitudinal dimension of said filter bag.

2. The dust bag of claim 1, wherein said protective layer is a nonwoven web of interconnected thermoplastic polymer fibers that are welded together.

3. The dust bag of claim 1, wherein said filter material is a single or multiple-layer composite with the synthetic fiber material.

4. The dust bag of claim 1, wherein said wall portions are welded together at their edges and that the melting temperature of the thermoplastic material of the protective layer fibers is higher than the melting temperature of the synthetic fiber thermoplastic filter material.

5. A method for producing a dust bag, comprising:

providing a first web of air-permeable filter material,

providing with the first web a second web of an air-permeable material, resistant to mechanical stresses caused by particles carried in an air flow and protecting said first web filter material, said second web being narrower than said first web,

forming said first web such that its two longitudinal edges overlap and the first web thus formed encloses said second web,

connecting said overlapping longitudinal edges of said first web,

providing an opening in said first web, said opening opposing said second web,

cutting off a portion of said formed first web with said second web positioned therein and having said opening, and

sealing said cut off portion at both ends, said second web being held at both sealed ends of said cut off portion.

6. The method of claim 5, wherein said first web comprises a paper filter material.

7. A method for producing a dust bag, comprising:

providing a first layer of air-permeable filter material and a second layer of an air-permeable material resistant to mechanical stresses caused by particles carried in an air flow to be filtered and protecting said first layer of filter material,

placing said second layer on said first layer of air-permeable filter material, said second layer containing synthetic thermoplastic fibers, said second layer being narrower than said first layer,

placing a third layer of an air-permeable filter material containing synthetic thermoplastic fibers on said second layer,

welding this sequence of layers together along a continuous edge line, and providing an inlet opening in said first or third layer for allowing the air to be filtered to enter the filter bag formed by said first and third layers, said opening being opposite said second layer, and

bonding said layers to form a dust bag.

8. The method of claim 7, wherein said second layer is narrower than said first and third layers and that said inlet opening is arranged opposite said narrow second layer.