CA2529523A1

CA2529523A1 - Wet out box for fibre wetting and method of use of the same

Info

Publication number: CA2529523A1
Application number: CA002529523A
Authority: CA
Inventors: Wayne Pattern; Andrzej Falacinski; Shane Green; Tim Robinson
Original assignee: Resin Systems Inc
Current assignee: RS Technologies Inc
Priority date: 2005-12-02
Filing date: 2005-12-02
Publication date: 2007-06-02
Also published as: WO2007062516A1

Abstract

A wet out box includes a container made from two abutting halves which are separable. A first seal face is carried by a first one of the two abutting halves. A second seal face is carried by a second one of the two abutting halves. A clamping system is provided to maintain the two abutting halves in abutting relation with the first seal face engaging the second seal face to maintain liquid resin within the container and wipe excess liquid resin from the fibres as fibres pass between the first seal face and the second seal face during fibre wet out.

Description

TITLE OF THE INVENTION:
Wet Out Box for Fibre Wetting and Method of Use of the Same FIELD OF THE INVENTION
The present invention relates to a wet out box used for fibre wetting during filament winding and a method of use of the same.

BACKGROUND OF THE INVENTION
Filament winding is a process in which wet resin is applied to filaments and the filaments are wound onto a mould. The resin sets and binds the filaments together, thereby forming the composite material. The wetting out of fibre glass is an integral part of the filament winding process because the physical properties of the final composite material are dependant, in part, upon the degree of fibre wet out achieved.

The present industry standard for wetting fibres utilizes a resin bath. Fibres are either pulled directly through the bath or passed over a rotating drum that sits partially submerged in a resin bath. In the latter process, resin coats the surface of the drum and is then transferred to the fibres as they contact the drum. In both processes the fibres are subsequently wiped of excess resin as they travel to a mandrel upon which they are wound with the excess resin being recycled.

SUMMARY OF THE INVENTION
According to a one aspect of the present invention there is provided a wet out box which includes a container made from two abutting halves which are separable.
A first seal face is carried by a first one of the two abutting halves. A second seal face is carried by a second one of the two abutting halves. Means are provided to maintain the two abutting halves in abutting relation with the first seal face engaging the second seal face to create a container that maintains liquid resin within the container.

According to another aspect of the present invention, there is provided a method of wetting fibres with resin using the wet out box described above.

BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:
FIG. 1 is a perspective view of wet out box constructed in accordance with the teachings of the present invention.
FIG. 2 is an exploded perspective view of the wet out box illustrated in FIG.
1, with the two halves separated.
FIG. 3 is an exploded end elevation view, in section, of the wet out box illustrated in FIG.1 showing the height of the wet out box in the vertical direction and the depth of the wet out box in the horizontal direction.
FIG. 4 is an end elevation view, in section, of the wet out box illustrated in FIG. 1.
FIG. 5 is a front elevation view of an interior face of one of the halves illustrated in FIG. 1 showing the height of the wet out box in the vertical direction and the width of the wet out box in the horizontal direction.
FIG. 6 is an end elevation view, in section, showing fibres passing through the wet out box illustrated in FIG. 1.
FIG. 7 is a perspective view of the wet out box illustrated in FIG. 1, with one configuration of the associated clamping assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a wet out box generally identified by reference numeral 10, will now be described with reference to FIG. 1 through 7.
Structure and Relationship of Parts:

Referring to FIG. 1, wet out box 10 includes a container 12 made from two abutting halves: a first half 14 and a second half 16. Referring to FIG. 2, halves 14 and 16 are separable. Referring to FIG. 6, when halves 14 and 16 are pressed together in abutting relation they form container 12, which is intended to contain a liquid resin 100. Referring to FIG. 4, container 12 has opposed sides 18 and 20 and a bottom 22. In order to avoid leakage between halves 14 and 16, a first seal face 24 is carried by first half 14 and a second seal face 26 is carried by second half 16. Referring to FIG. 4 and 6, container 12 defines a reservoir 36 and a passageway 105. The passageway consists of an upper inlet 28 through which fibres 102 to be wetted enter and a lower outlet 30 in bottom 22 through fibres 102 to be wetted exit.
A wet out path that fibres 102 follow from upper inlet 28 to lower outlet 30 is indicated by arrows 104. Wet out path 104 is more vertical than horizontal. As illustrated, it is shown as being substantially vertical, but it need not be. It could have an angular component. Wet out path 104 is substantially linear, although it may weave around over and under bars 32, as will hereinafter be further described. Refening to FIG. 5, each of first half 14 and second half 16 of container 12 is made from a plate 34 of material that is machined to form half of a reservoir 36. Peripheral slots 38 are provided for insertion of either first seal face or second seal face. The peripheral slots define an edge seal region 40 and a wiping seal region 42. The seals are extruded profiles and are replaceable in order to optimize the performance of the wet out box. Depending on the design of the box, there are one or more types of seals used in the wet out box. Regardless, the seals serve the same purpose.
Referring to FIG. 6, the seals act as a spacer between halves 14 and 16 of wet out box 10 and prevent fibres 102 from contacting the inside opposing faces of the container. The side seals do not contact fibres 102. The wiper seal across bottom 22 of wet out box 10 contacts the fibres and is the critical surface for resin impregnation. The thickness of the seal in conjunction with the depth of slot 38 determine, in part, the volume of reservoir 36.
These seals can be made from a variety of elastomeric materials such as butyl rubber, nitrile, vinyl, or other such materials and can therefore be tailored to meet the parameters required to optimize production cycles and fibre wet out. The profiles are extruded so that the seals fit into slots 38. There may or may not be provided slots 44 to accommodate insertion of over and under bars 32, depending on the application. Over and under bars 32 are made from extruded elastomers, such as butyl rubber, vinyl, nitrile, or any other suitable elastomeric material. Referring to FIG. 4 and 6, when two halves 14 and 16 are clamped together reservoir 36 and passageway 105 are formed. Wet out box 10 can be machined from a number of materials, such as wood, plastic or metal. Wet out box 10 may or may not be coated with a non-stick material such as Teflon or Needox in order to facilitate cleaning. Referring to FIG. 5, interior surface 46 of each plate 34 may or may not be treated with a non-stick coating, designated by reference numera148.

Refen-ing to FIG. 1, the width of wet out box 10 is relative to the number of fibres used in the process. The spacing between fibres 102 passing through reservoir 36 is sufficient to allow for complete wet out of the fibres. Wet out box 10 can be designed to accommodate a single roving or multiple rovings, dependant on the application.

Referring to FIG. 6, the space between halves 14 and 16 of container 12 determines in part the depth of the wet out box and is designed to provide reservoir 36 with sufficient volume and also provide clearance between fibres 102 and the interior opposed sides 18 and 20 of passageway 105.

Referring to FIG. 6, the height of wet out box 10 in part determines the volume of container 12. The height of wet out box 10 also determines the residence time of the fibres 102 passing through container 12 relative to the speed of the fibres.
The height of the resin in container 12 is defined by the distance from wiping seal at lower outlet 30 to the top of the resin in reservoir 36. The residence time is a function of the velocity of fibres 102 passing through container 12 and the height of the resin in container 12. Wet out box 10 can be designed to accommodate a variety of residence times based on the speed the application requires in order to completely wet out the fibres.
There are a various ways in which pressure may be applied to maintain two abutting halves 14 and 16 in abutting relation which can be manual or automated in nature. Referring to FIG. 7, a manual clamping assembly, generally identified by reference numeral 50 has been illustrated. Clamping assembly 50 has a series of clamps 52 which maintain abutting halves 14 and 15 in abutting relation. Each of clamps 52 has a rotating handle 54. Rotation of handle 54 serves to selectively vary pressure exerted by one of clamps 52. Referring to FIG. 6, this adjustment is made to adjust the sealing engagement between first seal face 24 and second seal face 26 to prevent resin leakage while maintaining adequate wet out of fibres 102 with liquid resin 100.
Operation:
The use and operation of wet out box 10 will now be described with reference to FIG. 1 through 7.

Referring to FIG. 6, wet out box 10 is designed for use in a filament winding process. It is preferred that a vertically downward wet out path 104 be traveled by fibres 5 102 during wet out. The process is characterized by low resin volumes and low residence time. First seal face 24 and second seal face 26 are provided by removable disposable seals, which form a seal that acts to impregnate fibres 102 with resin as fibres 102 pass between them. Two halves 14 and 16 are pressed together in abutting relation to create container 12 with reservoir 36.
Wet out box 10 is mounted on filament winding equipment (not shown) so that fibres 102 passing through wet out box 10 can be directed to the winding process immediately after being wet out. The fibres used may be E-glass, S-glass, carbon fibres, basalt fibres, aramid fibres, or any other fibre associated with composite reinforcing material.

Referring to FIG. 1, the amount of resin that remains on fibres 102 after wet out is controlled by a series of pressure points, indicated by arrows 108, directed against the face of wet out box 10 to apply localized pressure onto the seal formed by the engagement between first seal face 24 and second seal face 26. This pressure can be adjusted during production runs in order to eliminate leakage, control wet out, and to optimize the resin to fibre ratio of the final composite material. Referring to FIG. 7, one manner of applying pressure is illustrated; that being through a clamping system 50.

Referring to FIG. 6, the low volume and short residence time of liquid resin held in reservoir 36 and passageway 105 prevents the polymerisation of liquid resin 100 prior to liquid resin 100 being transferred out of wet out box 10 by fibres 102 passing through wet out box 10. The residence time of the resin in wet out box has been calculated to be approximately 35 seconds during full scale production. This configuration also allows for the complete evacuation of liquid resin 100 through lower outlet 30 at bottom 22 in order to empty wet out box 10 rapidly. Referring to FIG. 2, two halves 14 and 16 of wet out box 10 are advantageously designed to be easily separated by removing the force applied in order to dismantle wet out box 10. Referring to FIG. 6, first seal face 24 and second seal face 26 act to prevent the loss of liquid resin 100 and acts to force air from fibres 102 and force resin into fibres 102. Referring to FIG.
5, these seals are easily and advantageously removable from slots 38 in plates 34 out of which first half 14 and second half 16 are formed.

Referring to FIG. 6, where over and under bars 32 are used, the contact between over under bars 32 and fibres 102 passing over the surface of over and under bars 32 acts to force air from fibres 102 and force liquid resin 100 into fibres 102.
Referring to FIG. 5, over and under bars 32 are easily and advantageously removable from slots 40 in plates 34 out of which first half 14 and second half 16 are made.

Wet out box 10 should be designed to suit the process with which it is to be used.
One of the key factors that effects the structure of wet out box 10 is the intended speed of the filament winding process. Once the speed of the process is known, wet out box 10 is made with sufficient height to allow a thorough wet out of fibres passing through wet out box at the intended speed. Reservoir 36 is made of a sufficient size to continuously supply liquid resin 100 required for wet out at the intended speed. Once wet out box 10 is built, installed and operational, fine adjustments are made by altering the force applied at critical pressure points that hold first half 14 and second half 16 in abutting relation to apply pressure upon first seal face 24 and second seal face 26. Referring to FIG. 7, one way of making such adjustments is through a manual clamping system 50. An automated system could also be used.

Wet out path 104 could be made horizontal, but there are significant advantages to providing a vertical wet out path. When wet out path 104 through wet out box 10 is more vertical than horizontal, with fibres 102 exiting through bottom 22, clean up is simplified.
Gravity is used to drain liquid resin 100 from wet out box 10. Referring to FIG. 2, the two halves 14 and 16 are then separated for internal cleaning. Depending on the material used to fabricate the halves 14 and 16, a non-stick coating may be utilized to prevent the resin from sticking to wet out box 10.

Although this method was initially designed to be used with polyurethane, it has been shown that polyester, vinyl ester, epoxy or any other resin acting as a composite matrix can be used with this method.

Examples:

The first example involves a single fibre being wet out at low speed. For the purposes of research, a narrow unit was constructed to wet out a single roving in order to wind sample rings for testing. Fibre was passed through this box at a rate of 20 feet per minute. The total width of the box was 3 inches, with the reservoir being 1 inch wide. The length of the box (in the direction of glass travel) was 7 inches. The seals used on this box were 1 inch wide strips of butyl rubber and were attached to the body of the box with glue.
The material used to make this box was 1 inch thick multi-directional fibre (MDF) board.
The wiping seal was created by an angled slot across the exit of the box such that the face of the wiping seal started flush with the inside surface of the box, and rose up to be flush with the height of the side seals. Pressure on the seal to control the degree of wiping was controlled by a simple C-clamping.

The second example involves 24 fibres being wet out at medium speed. For the purposes of proto typing, a medium width unit was constructed to wet out twenty four rovings in order to wind conveyor rollers. Fibre was passed through this box at a rate of 60 feet per minute. The total width of the box was 10 inches, with the reservoir being 8 inch wide. The length of the box (in the direction of glass travel) was 12 inches.
The seals used on this box were of two designs. The side seals were 1/4 by 3/8 inch extruded vinyl. The wiper seal was a I and 1/2 inch wide tapered vinyl extrusion that was 3/16 inch at the narrow end rising to 3/8 at the seal end. The seals were inserted into slots machined into the body of the box. The material used to make this box was 1 inch thick ultra high molecular weight (UHMW) polyethylene. Pressure on the seal to control the degree of wiping was controlled by a series of adjustable grips.
The third example involves two wet out boxes in parallel, each wetting out 96 fibres at high speed for a total of 192 rovings total. For the purposes of production, a pair of wide boxes were constructed to wet out at ninety six rovings each in order to wind utility poles. The dual boxes also incorporated over and under bars to facilitate fibre wet out. Fibre was passed through this box at a rate of 200 feet per minute. The total width of the box was 24 inches, with the reservoir being 22 inch wide. The length of the box (in the direction of glass travel) was 12 inches. The seal used on this box was a one piece 1/2 inch diameter round nitrile extrusion. The seal was inserted into a single slot that ran down the edge of the inside of each of the halves of the box, across the bottom, and back up the inside edge of the box. The material used to make this box was 1 inch thick ultra high molecular weight (UHMW) polyethylene. Over/under bars were used to facilitate wetting of the fibre as the fibre passed through the reservoir. The over/under bars were made of the same nitrile extrusion as the seals. The over/under bars were located in slots cut into the body of the box and running perpendicular to the direction of the travel of the glass.
Pressure on the seal to control the degree of wiping was controlled by an automated hydraulic clamping system.
Additional Benefits:
The seals in the wiping section of the box create a zone of high pressure within the body of the resin at the entrance to the seal area which increases the penetration of the resin into the glass fibres as the fibres pass between the seals. The seals in the wiping section also allow the wet out box to impregnate glass fibres with low viscosity resins.
The wet out box eliminates resin loss by having the wiping of the glass fibres occur at a point on the wiping seal that is internal to the wet out box. The wet out box eliminates the need to recycle the resin, as excess resin is prevented from leaving the box. The width of the container can be specified to accommodate any number of glass fibres. The height of the container can be specified to increase or decrease the time it takes for the glass to pass through the container.
The volume of the container is minimized to allow for rapid evacuation of the resin from the container as resin is removed from the container by the fibres passing through and carrying the resin from the container and thereby minimizing the residence time of the resin in the container. The volume of the container is minimized to allow for minimal loss of resin if the container is opened while resin is present in the container.

Cautionary warnings:
It would be counter productive to orient the box any way other than vertically (unless out of necessity it was being fit into a confined space). The vertical orientation allows for purged air to rise freely to the surface. It also allows for new resin to enter the top, with older resin leaving at the bottom. If the box is tipped on its side, the resin would run out unless some type of extra reservoir is incorporated. The vertical orientation also allows for the box to run completely dry (the small volume of the reservoir allows this to happen quickly) to facilitate cleaning. Horizontal boxes have a "floor" on which the resin sits and has to be drained. The box could be tipped to the angle at which the resin begins to run from the reservoir. It could lie flat and have an elevated reservoir.
This would not affect the way the seal works. However, if the air was unable to exit the box by bubbling up, it could end up exiting through the seal and defeating the wet out process. As long as there is a method of keeping the resin in the box, any angle would suffice, albeit less efficiently.
In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.

Claims

1. A wet out box, comprising:
a container made from two abutting halves which are separable;
a first seal face carried by a first one of the two abutting halves;
a second seal face carried by a second one of the two abutting halves; and a means to maintain the two abutting halves in abutting relation with the first seal face engaging the second seal face to maintain liquid resin within the container;
and the container defining an upper inlet, a lower outlet and a wet out path that the fibre follows from the inlet to the lower outlet which is more vertical than horizontal, the first seal face and the second seal face forming a wiper seal across the lower outlet and wipe excess liquid resin from the fibres as fibres pass between the first seal face and the second seal face during fibre wet out.

2. The wet out box as defined in Claim 1, wherein the container has an open top to allow the fibres to enter the liquid resin.

3. The wet out box as defined in Claim 1, wherein the means for maintaining the two abutting halves in abutting relation is a clamping system.

4. The wet out box as defined in Claim 3, wherein means is provided for selectively varying pressure exerted by the clamping system thereby permitting the sealing engagement between the first seal face and the second seal face to be adjusted to prevent resin leakage and maintain adequate wet out of the fibres with resin.

5. The wet out box as defined in Claim 3, wherein the means to maintain the two abutting halves in abutting relation may be manual or automated, with the variable clamping force generated by one of mechanical, hydraulic, or pneumatic means.

6. The wet out box as defined in Claim 3, wherein the clamping system has the capacity to relieve the pressure exerted on the two abutting halves of the container in order to separate the two abutting halves at any time in order to access the interior of the container.

7. The wet out box as defined in Claim 3, wherein the clamping system has the capacity to relieve the pressure exerted on the two abutting halves of the container in order to separate the two abutting halves at any time in order evacuate the contents of the container.

8. The wet out box as defined in Claim 1, wherein the path taken by the glass fibre is substantially linear.

9. The wet out box as defined in Claim 1, wherein the path taken by the glass fibre weaves around over and under bars.

10. The wet out box as defined in Claim 1, wherein the container may have an interior surface coated with a non-stick coating.

11. A method of wetting fibres with resin, comprising the steps of:
providing a container with an open top and closed on the sides and bottom, made from two abutting halves which are separable, with a first seal face carried by a first one of the two abutting halves and a second seal face carried by a second one of the two abutting halves;
filling the container with liquid resin;
passing the fibres into the container from the top, through the container filled with liquid resin, and out of the bottom of the container between the first seal face and the second seal face, while applying pressure to maintain the two abutting halves in abutting relation with the first seal face engaging the second seal face to maintain a volume of liquid resin within the container; and the container defining an upper inlet, a lower outlet and a wet out path that the fibre follows from the inlet to the lower outlet which is more vertical than horizontal, the first seal face and the second seal face forming a wiper seal across the lower outlet to wipe

12 excess liquid resin from the fibres during fibre wet out.

12. The method as defined in Claim 11, vertical orientation of the wet out box allowing air purged from the fibres to travel upwards through the resin to exit from the surface of the resin.