Inversion liner and liner components for conduits
View Patent ↗Inversion liners are provided which in a first embodiment include first and second flexible fabric layers joined to first and second glass fiber containing layers and joined in tubular form, whereby the first and second flexible fabric layers face one another. The second glass fiber containing layer further is bonded to a thin, third flexible fabric layer. A substantially fluid impermeable layer is applied to the opposite side of the thin, third flexible fabric layer. This method and liner construction can save one or more steps in the manufacture of glass-reinforced, polyester felt liners.
1. A method of making a tubular inversion liner or liner block, comprising:
a) providing a first flexible fabric layer fastened to a first glass fiber containing layer;
b) providing a second flexible fabric layer fastened to a second glass fiber containing layer;
c) combining said first and second flexible fabric layers and said first and second glass fiber containing layers by melt bonding or adhesion without stitching or needling, whereby said first and second flexible fabric layers face one another and are sandwiched between said first and second glass fiber containing layers; and
d) joining a third flexible fabric layer, having a lesser thickness than either of said first or second flexible fabric layers, to said first or second glass fiber containing layers, and directly applying a substantially fluid impermeable layer to said third flexible fabric layer, whereby said substantially fluid impermeable layer becomes the outermost layer prior to inversion.
2. The method of claim 1 wherein said third flexible fabric layer is stitched to at least said second glass fiber containing layer.
3. The method of claim 1 wherein said third flexible fabric layer comprises a nonwoven felt layer.
4. The method of claim 3 wherein said nonwoven felt layer comprises a thickness of about .1-1.0 mm.
5. The method of claim 1 wherein said third flexible fabric layer comprises a nonwoven veil and the substantially fluid impermeable layer is a resinous coating or thin film adhered thereon.
6. The method of claim 5 wherein said veil comprises a nonwoven polyester or acrylic felt.
7. The method of claim 1 wherein said substantially fluid impermeable layer comprises a polyurethane or acrylic latex coating, or a melt-bonded polyolefin film, which is applied after said third flexible fabric layer is joined to either said first or second glass fiber containing layer.
8. A tubular inversion liner made in accordance with the method of claim 1 .
9. The method of claim 1 wherein said substantially fluid impermeable layer comprises a polyurethane or acrylic latex coating, or a melt-bonded polyolefin film.
10. The method of claim 1 , further comprising an inversion step having an inversion rate which is at least 10% faster than the inversion rate for a 100% polyester felt liner of like dimensions.
11. The method of claim 1 , wherein the method further comprises joining a plurality of blocks by melt bonding or adhesion without stitching or needling to form a liner having a total thickness of about 12 mm to 50 mm.
12. The method of claim 1 , wherein the liner or liner block has a thickness of about 9 mm.
13. The method of claim 1 , further comprising joining a further flexible fabric layer between the first and second flexible fabric layers by melt bonding or adhesion to each of the first and second flexible fabric layers without stitching or needling, the further flexible fabric layer having a thickness of 10 mm to 20 mm.