CROSS-REFERENCE TO RELATED APPLICATION
BACKGROUND OF THE INVENTION
1 ;2 .
APPARATUS FOR PRODUCING A MAT the fiber collection surface upon which fiber and a
binder are directed so that gutters bordering the collection surface receive fugitive fibers which accumulate on and drop from the side walls. In addition, an upper 5 wall and an end wall are faced with moving belt-like This invention complements and employs features of conveyors so that fugitive fibers which cling to their the contoured walls of the fiber collection chamber dis- surfaces are carried from the container and removed closed in a patent application of Brian J. Rayle, Lester therefrom by a brush. Paoletti U.S. Pat. No. 3,551,250 Fisher and Harvell M. Smith entitled "Collection of Dec. 29, 1970 for "Apparatus for Making Uniform Chamber for Making Mats of Inorganic Fibers" which 10 Mats of Inorganic Fibers" and A. B. Havens U.S. Pat. was Filed herewith. No. 3,582,432 of June 1, 1971 for "Fiber Mat Forming
Hood With Movable Side Walls" disclose fiber collection chambers having side walls made up of vertical 1. Field of the Invention slats coupled to present a continuous side wall surface
Mats of mineral fibers have been formed by drawing 15 between a source of a primary stream containing fibers a stream of gas in which fibers and a binder are en- and a foraminous fiber collecting surface. These side trained onto a collecting surface which is advanced wall slats were coupled to form a continuous structure through a region in which fiber inpinges thereon to pro- trained over vertical head pulleys and tail pulleys so the gressively accumulate the desired mat thickness. It is wall presented to the collection chamber interior could common practice to confine the fiber in its flight from 20 be advanced out of the chamber and during their rea fiber dispensing means to the collecting surface. Such turn run for readmission to the chamber could be confining means has been in the form of walls which washed and dried. Each of the above structures sought enclose the flight path to form a collection chamber to minimize the buildup of binder and fiber by moving which may include side walls and in some instances the wall of the collection chamber to a cleaning station, covering walls partially closing the region from which 25
the fiber is dispensed. While the primary objective of these prior art devices
Binder and fibers follow a generally direct path from was the improvement of product quality by elimination their sources to the collecting surface. However, some of the random deposition of fiber wad debris on the turbulence occurs in the mixing of the streams includ- blanket another significant aspect appeared to have ing the primary stream of fiber and a high temperature, 30 been overlooked. In particular the lost time due to the high velocity gas employed to attenuate the fiber in the need to clean the walls of the collection Chamber. Such case of glass, a secondary stream of ambient air of low an objective can be achieved only if all surfaces where velocity and another stream of binder, usually an aque- fiber can collect and wads can form are cleaned during ous solution or suspension of a thermosetting resin. operation. If surfaces such as the back walls of the While a suction behind the fiber collection surface 35 chambers are not cleaned when the side walls are maintains the flight path for the preponderance of the cleaned as by a moving wall arrangement, the clean-out fiber and binder to that surface, eddies are present time may be reduced but shut downs for periodic cleanwhich cause resin, fibers and resin-coated fibers to im- ings will still be necessary.
pinge upon the walls of the collection chamber. The Further, the joints and non-contiguous panels with fiber tends to buildup into wads, some developing as 40 their seams inside the chamber contribute substantially clumps in flight particularly in the upper portions of the to wad formation, chamber and other as accumulations on the walls. Binder collects in these wads so that they are carried to the mat in a wet condition. Some fiber remains on the The present invention relates to fiber collection walls for longer periods and buildup. As it remains, it 45 chambers and more particularly.to such chambers havdries and cures. Some of the dried clumps of fiber ing movable walls arranged to be advanced from the break off due to the turbulent air flow and cause dry chamber to a cleaning station. It offers features absent cured wads to collect on the blanket. from the prior art including the utilization of moving
The above problems are particularly troublesome and cleaned walls for all surfaces where fiber can colwhere the fiber collection surface is at the bottom of 50 lect, the form of the walls, the method of their mounttrie chamber and are increased further when the source ing, the cleaning techniques and apparatus, the means of the primary stream and binder are situated above the of altering wall from a planar construction to enhance fiber collection surface. Gravity then enters into the fiber distribution, and the seals in the chamber walls, mechanism delivering the heavy wads to the blanket so 5J It has been found that a relatively continuous surface that the product quality is reduced by both "wet wads" as a movable side wall presenting no seams to the fiber and "dry wads" which retain their undesirable identity and binder materially enhances the resistance to the acin the final product. Further production is significantly cumulation of fiber, particularly since fiber tends to adimpeded by the frequent shut downs of the apparatus here more readily to even slight discontinuities in the to clean the walls of the collection chamber. Such ^Q forming chamber wall. Smooth walls facilitate washing, cleaning involves wash-downs of the chamber walls . The belt surfaces employed are arranged such that the and, less frequently, a scrape-down of those walls. surfaces can be displaced intermediate the extremes of
2. Description of the Prior Art the loop to shape the walls and approximate a Venturi
Heretofore efforts to avoid fugitive fiber contamina- or other form desired from the point of view of ention of mat product have been undertaken. In R. N. 65 hanced control of fluid flow for the stream entraining BrownleeU.S. Pat. No. 2,389,024 of Nov. 13, 1945 en- the fibers.
titled "Means for Forming Fiber Felts" a collection An advantageous feature resides in a vertical loop
chamber is disclosed which is substantially wider than orientation of the side walls and end wa}ls such that a