JPH07148409A - Air filtration medium and production thereof - Google Patents

Abstract

PURPOSE: To produce a glass fiber air filtration medium in a few steps at a low cost by randomly mixing specified coarse and fine glass fibers in a specified proportion and binding the fibers with a binder. CONSTITUTION: About 25-35 wt.% glass fibers having about 2 μm average diameter and about 65-75 wt.% glass fibers having about 6 μm average diameter are mixed and formed into a blanket 12. The glass fibers are randomly mixed and bound together at the crossed parts with a resin binder sprinkled on the glass fibers during the formation into the blanket 12. An air permeable lightweight meshed lining sheet 14 is fitted to the glass fiber blanket 12 to obtain the objective glass fiber air filtration medium 10.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to glass fiber air filtration media, and more particularly to an improved glass fiber air filtration media formed from a blanket of delicate and coarse glass fibers and a method of making the air filtration media.

[0002]

BACKGROUND OF THE INVENTION Traditionally, glass fiber air filtration media are formed from fiber blankets having glass fibers of a particular average fiber diameter designed to achieve a particular air filtration role. As a result of the many different air filtration requirements supplied on the market, about 20 different air filtration media products were needed to provide a complete product line. These about 20 different air filtration media products with different average fiber diameters required manufacturing process adjustments to produce different products. Process adjustments or production changes from one product to another produce waste and require manpower,
It reduces power output and thus increases manufacturing costs.

The present invention solves many of the problems of the prior art by providing an air filtration media product that can perform the functions of many conventional air filtration media products.
In practice, through the use of the air filtration media product of the present invention,
The number of individual air filtration media products required for the complete product line is reduced from about 20 to about 6. This greatly reduces the number of process changes required to produce different air filtration media and results in cost savings due to reduced waste, reduced manpower requirements and increased production line productivity. Become.

The present invention comprises an air filtration medium which is a glass fiber blanket containing a mixture of delicate and coarse glass fibers. The blanket contains about 25% to 35% by weight glass fibers having an average diameter of about 2 microns, and about 65% to 75% by weight glass fibers having an average diameter of about 6 microns, respectively. The coarse and delicate fibers are randomly mixed with each other, and the resulting air filtration media product can not only replace many prior art air filtration media products, but also the dust retention capacity of the air filtration media. Is an advantage that can be increased.

The above glass fiber air filtration media blanket laterally aligned a gaseous stream of glass fibers from a plurality (typically 10 to 20) of glass fiber generators that were laterally aligned and spaced. It is formed by directing it against a collecting surface that moves in a direction perpendicular to the glass fiber generator. These glass fiber generators are tuned such that every other generator produces fine diameter glass fibers and the remaining generators produce coarse diameter glass fibers. The gaseous stream of glass fibers coming from the individual glass fiber generators is mixed between the glass fiber generators and the moving collecting surface, resulting in delicate and coarse particles in the blanket formed on the collecting surface. The glass fibers are randomly mixed. The binder is sprinkled over the glass fibers in a gaseous stream, which binds the fibers together at their intersections inside the blanket, and in the case of special products made with a backing. It serves to bond the air permeable backing to the blanket.

Each glass fiber generator includes a glass melting unit that emits a plurality of continuous glass twists or filaments, and a dampening burner that forms a continuous glass twist in a gaseous stream of glass fibers. The fiber diameter of the glass fiber produced by each glass fiber generator is
It is controlled by adjusting the melting rate of the melting unit. The melting rate of the fusing unit is increased to make coarse fibers and reduced to make fine fibers.

[0007]

EXAMPLE FIG. 1 shows a glass fiber air filtration medium 1 of the present invention.
0 is shown. The air filtration medium typically includes a glass fiber blanket 12 with a lightweight spunbond backing 14. The glass fiber blanket 12 is formed from a random mixture of delicate and coarse diameter glass fibers. Delicate diameter glass fiber,
Blanket 12 having an average diameter of about 2 microns
Within about 25% to 35% by weight of the glass fiber is formed. Coarse diameter glass fibers have an average diameter of about 6 microns and within the blanket 12 about 6 of the glass fibers.
Forming from 5% to 75% by weight. These glass fibers are bound together at their intersections by a resin binder sprinkled over the glass fibers during the formation of blanket 12. This fiberglass blanket is
It is typically between 0.11 and 1.50 inches thick and has a density of between about 0.4 and 1 pound per cubic foot.

The above glass fiber blanket 12 includes:
Typically, a commercially available, air permeable, lightweight, spunbond backing sheet 14 is provided. Two backing sheets used on the air filtration media of the present invention include Reema
y, Style 2004 spun-bonded polyester backing sheet and Cerex, style 230
4, there is a FiberWeb spun-bonded nylon backing sheet. The glass fiber blanket 12 is adhesively bound to the backing sheet 14 by the resin binder present within the glass fiber blanket.

2 and 3 show an apparatus 16 for producing the glass fiber air filtration medium 10 of the present invention. The apparatus includes glass fiber generators 18 and 19, forming tube 20 and U-chute 22, spray nozzles 24 and 25 for binder and water addition, and a collection station 26. A conventional regenerative oven, not shown, is used to regenerate the resin binder in the air filtration medium 10.

As best shown in FIG. 2, glass fiber generators 18 and 19 are aligned across the width of device 16. Although only 10 glass fiber generators are shown here, the number of glass fiber generators used can be appropriately changed, and 12 glass fiber generators are generally used. .

The glass fiber generators 18 and 19 described above include glass marble melting pots 28 and 29, respectively, and pulling rollers 30 and burners 32, respectively. These melting pots 28 and 29 receive glass marble from a hopper (not shown). Each melting pot receives glass marble on request. As the marble melts, more marble will automatically flow into the melting pot to keep the pot full. Like a burner,
The high temperature source of thermal energy is such that, within each melting pot, the viscosity of the molten glass forms a primary continuous strand or filament 36 extruded through a hole in the bottom of the melting pot. , Marble is heated and melted. These primary continuous filaments 36 are
It is fed by a pulling roller 30 before a damping burner 32 and formed into a secondary gaseous stream of fibers. Damping burner 32 is a commercially available gas / oxygen-fired Selas burner.

The diameter of the primary continuous filament 36 coming from each pot can be adjusted by the rate at which the glass is melted in the melting pot. The filaments 36 are ejected or drawn from the pots by pulling rollers 30 at substantially the same rate throughout. This increases the input of thermal energy into the melt pot 28 or 29 and also increases the output of the melt pot, producing a larger diameter filament 36. By reducing the input of thermal energy into the melt pot 28 or 29 and also reducing the output of the melt pot, filaments 36 of delicate diameter are produced.

The dampening burner 32 directs the hot gaseous blast in a substantially horizontal direction which is perpendicular to the path of the continuous filaments 36 fed in front of the burner. This hot gaseous blast attenuates the filaments into man-made glass fibers, which are carried to the collecting surface of collection station 26 by the hot gaseous blast.

The hot gaseous stream coming from the glass fiber generators 18 and 19 as the stream approaches the collection station 26 forms tube 20 and U-chute 22.
Pass through. Side wall of forming tube 20 and U-chute 2
As the two converge in the direction of the forming station 26, the gaseous streams of glass fibers are mixed, and thus the fibers from the different glass fiber generators 18 and 19 are mixed.

A binder addition system consisting of a binder spray nozzle 24 and a water spray nozzle 25 is located between the forming tube 20 and the U-chute 22. The headers of these spray nozzles 24 and 25 are located at the top of the gaseous stream of glass fiber binder binder nozzle 24.
And extends across the width of the device 16 with a water spray nozzle 25 located below the gaseous stream of glass fibers. These nozzles 24 and 25 respectively spray the resin binder and water sprayed onto the glass fibers in a gaseous stream. Water sprinkling serves to cool the gaseous stream of hot glass fibers.

The collection station 26 is an endless, air permeable, chain mesh conveyor belt 3.
8, suction box 40 and backing supply assembly 4
It consists of two. Chain mesh conveyor belt 3
8 passes over a series of guide rollers 44. As the chain mesh conveyor belt 38 passes in a substantially vertical direction which is perpendicular to the direction of the glass fiber gaseous flow, the glass fibers are collected on the conveyor belt to form the blanket 12. The gaseous stream of mixed glass fibers impinges on the conveyor belt 38, and as the gas passes through the conveyor belt, the glass fibers are left on the conveyor belt to form the blanket 12.

After blanket 12 is formed, it is transferred to oven conveyor 46 and chain mesh collection belt 38 passes through chain cleaner 48 before returning to the collection portion of its path. Chain cleaner 4
8 sprays water through the collecting bell and prevents the establishment of resin binder and glass fibers on the belt 38 which suppresses the collecting action.

The suction box 40 is provided on the conveyor belt 3
Air is drawn through 8 to allow the fibers to collect in blanket 12 on the vertically moving surface of conveyor belt 38. This air is exhausted or sucked in by the fan 52.
Is exhausted through the exhaust stack 50.

The supply assembly 42, when the backing is used on the air filtration media, starts the vertical stacking run of the belt and at the same time conveys the lightweight spun-bonded backing mat 14 to the conveyor belt. 38, which actually collects the glass fibers on the backing mat 14.
Two supply rollers are provided so that one roller can run out and the other roller can be immediately introduced into the process.

As mentioned above, the glass fiber air filtration medium 10 directs the gaseous stream of glass fibers from the fiber generators 18 and 19 to the collection conveyor 38 of the collection assembly 26.
Formed by facing against. Every other fiber generator 18 is installed to produce fine diameter glass fibers, and the remaining fiber generators 19 are installed to produce coarse diameter glass fibers. As the glass fibers pass through the forming tube 20 and the U-chute 22, the gaseous streams of glass fibers from the individual glass fiber generators are mixed so that each fine and coarse fiber is randomly mixed. Become. Thus, the blanket of glass fibers 12 collected directly on the backing mat 14 or collection conveyor 38 contains randomly mixed delicate and coarse glass fibers. The resin binder added by the spray nozzle 24 binds the glass fibers together at the points of their intersection, and also blanket 1 if a backing mat is used.
2 has a function of adhesively binding the backing mat 14.
The blanket 12 passes from the collection conveyor 38 to the oven conveyor 46 where the blanket is conveyed to a conventional regenerative oven to regenerate the resin and trim the air filtration media product thickness. The regenerative oven sandwiches a glass fiber blanket 12 between upper and lower chain mesh conveyor belts that are spaced a predetermined distance to form a blanket into an air filtration media product of a given heat. . Thus, when it is desired to produce a higher density air filtration media product 10, the collection conveyor is slowed down and more glass fiber is accumulated,
A thicker blanket 12 is formed. Conversely, if a lower density or lighter weight product is desired, the collection conveyor 38 is sped up to accumulate less glass fiber and produce a thinner glass fiber blanket 1.
2 is formed.

As shown in FIG. 3, fine diameter glass fibers are produced on the fiber generator 18 and coarse diameter glass fibers are produced on the fiber generator 19. As mentioned above, the relative diameter (fine or coarse) of the glass fibers produced by the fiber generators 18 and 19 is, in principle,
It is governed by the draw rate or output of the melt pot 28 or 29 associated with the fiber generator. Since the pulling roller 30 pulls the continuous filament 36 emitted from the melting pots 28 and 29 at a constant rate, the higher the output of the melting pot, the larger the diameter of the continuous glass filament produced. As an example, a melt pot with 100 holes and a draw rate of about 10 pounds per hour produces glass fibers with an average diameter of about 2 microns, and the same pot is run with a draw rate of about 29 pounds per hour. When produced, it produces fibers having an average diameter of about 6 microns. Thus, by adjusting every other melt pot 18 to about 10 pounds per hour and the remaining melt pots 19 to about 10 pounds per hour, delicate 2 micron glass fiber. Glass fiber blanket 12 is produced comprising about 25% to 35% by weight and about 65% to 75% by weight of coarse, 6 micron glass fibers.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a glass fiber air filtration medium of the present invention.

FIG. 2 is a schematic front view of an apparatus used in the process of the present invention.

FIG. 3 is a schematic plan view of an apparatus used in the process of the present invention.

[Explanation of symbols]

 10 Air Filtration Media 12 Glass Fiber Blanket 14 Backing Sheet 16 Filtration Media Manufacturing Equipment 18, 19 Glass Fiber Generator 20 Forming Tube 24, 25 Spray Nozzle 26 Collection Station 28, 29 Marble Melting Pot 30 Roller 32 Damping Burner 38 Belt

Claims (6)

[Claims] 1. About 25% to 35% by weight of the glass fibers have an average diameter of about 2 microns and about 65% by weight.
To 75% by weight comprises a blanket of glass fibers having an average diameter of about 6 microns, the glass fibers being randomly mixed and cohesively bound together by a binder. Medium. 2. The glass fiber air filtration medium of claim 1, wherein a porous, air permeable, mesh finish is adhesively bonded to the surface of the blanket. 3. The fiberglass air filtration medium of claim 1, wherein the blanket has a density of between 0.4 and 1 pound per cubic foot. 4. A plurality of laterally aligned and spaced glass fiber generators for producing a gaseous stream of glass fibers,
A moving collecting surface located in the flow path of the glass fibers and moving in a direction perpendicular to the laterally aligned glass fiber generators for collecting said glass fibers in a blanket; A method for forming a glass fiber air filtration medium in an apparatus comprising means for adding a binder to a gaseous stream of glass fibers prior to depositing on the glass fiber generator. Producing glass fibers having an average fiber diameter of about 2 microns on a first set of, and producing glass fibers having an average fiber diameter of about 6 microns on a second set of said glass fiber generators, The glass fiber generators of the first set are interleaved with the glass fiber generators of the second set, and the gaseous stream of glass fibers contacts a collecting surface to cause the glass fiber generators to The glass fibers from the first set were randomly mixed with the glass fibers from the second set of glass fiber generators and randomly mixed from the first and second sets of glass fiber generators. A method of mixing the gaseous stream of glass fibers prior to forming an air filtration media blanket having the glass fibers. 5. Each glass fiber generator includes a glass melting unit that emits a plurality of continuous glass twist yarns and a damping burner that forms a continuous glass twist yarn into a gaseous stream of glass fibers. The method according to claim 4, wherein the diameter of the glass fiber produced in each said glass fiber generator is controlled by adjusting the melting rate of the melting unit. 6. The method of claim 5, wherein the density of the blanket is controlled by adjusting the speed of the moving collecting surface while keeping the thickness of the air filtration medium constant.