Apparatus for resin impregnation

A two roller impregnator for impregnating a fiber with (catalyzed) resin. The resin is kept directly above the two rollers and enclosed with a set of dams to create a resin pool. A different resin pool may be generated for each roller. The resin release mechanism facilitates for the resin and if necessary, a catalyst, to be released into the resin pool(s). Temperature of the resin pool can be controlled, along with the temperature of each roller. A post-impregnation catalyst activator can be utilized to activate the catalyst.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to an apparatus for resin impregnation and, more specifically, to an apparatus for controlling resin impregnation of a fiber.

2. Description of Related Art

Traditionally, fibers are impregnated by passing them manually through a resin bath, using an applicator roller, or injection die. These methods require a high burden of manual handling, and typically do not result in non-uniform impregnation, and may result in the entrapment of air within the resin. This leads to a weakening of the part. Such methods and other can be found in U.S. Pat. Nos. 5,766,357, 6,387,179, and 6,179,945.

U.S. Pat. No. 7,413,623 describes many of the methods for resin impregnation of the prior art. U.S. Pat. No. 7,413,623 is incorporated herein by reference. U.S. Pat. No. 7,413,623 improves upon the prior art by employing the use of two roll impregnators, wherein the fiber passes through a resin pool directly above the two rollers. The resin pool resides sits above the two impregnation rollers and is held in from the sides by a set of dams. When the fiber passes through the two rollers, full impregnation is fostered, excess resin removed, and the impregnated fiber degassed. At least one of the two impregnator rollers can be adjusted to be closer or further from the other impregnator roller, allowing for control of the tension applied on the fiber. Outside of the two impregnation rollers is a set of alignment/tensioning bars.

U.S. patent application Ser. No. 12/208,322, published on Mar. 12, 2009, describes a system and method for using at least one roller to impregnate fibers with a liquid resin within a pressurized zone. The use of two rollers for impregnation with a pressurized zone at the output side of the rollers is also described.

None of the existing techniques for impregnation using impregnation rollers describe a convenient means for automatically adding resin to the resin pool. In addition, the existing techniques do not employ the use of temperature control for the resin pool or rollers, and the use of a latent catalyst system, which is automatically activated after the impregnation.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a novel apparatus for resin impregnation and wet-out of a fiber. The apparatus employs two impregnator rollers (nip rollers) for impregnating the resin into the fiber. A resin pool sits above the two impregnator rollers, and is held in on the sides by a set of dams. In one embodiment, two different resin pools exist, one for each side of the fiber. The resin pool may be filled automatically through a resin release mechanism. The resin may be mixed with a catalyst prior to being added to the resin pool to form a catalyzed resin. The resin is fanned into the resin pool(s).

In another embodiment, the impregnating rollers may have internal heating or cooling to control the temperature. Temperature may need controlled in order to maintain the proper viscosity of the resin.

If a latent catalyst system is utilized, the catalyst may be activated by heat or light. This is performed through the post-impregnation catalyst activator, placed below the impregnated rollers to automatically activate the catalyst after impregnation.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT(S)

While this invention can take various forms, it generally provides a novel apparatus for impregnating resin onto a fiber, sometimes known as wet-out. The apparatus of this invention generally uses a two roller system to perform the impregnation. The novel features of the apparatus make this two roller impregnation system's usability and performance superior to previous ones. Usability and performance are enhanced through a set of features, as will be described in various embodiments of the invention below. The various embodiments describe a novel roller impregnator system comprised of gears, dual pooling of resin, a resin release mechanism, temperature control of the rollers, and a post-impregnation catalyst activation system.

FIG. 1is a diagram of an embodiment of the present invention. The apparatus ofFIG. 1is held together by a frame, which has a right side, left side, and a number of crossbars connecting the right and left sides. The frame may have wheel attachments at the bottom of the legs, which allow for easy mobility of the apparatus. At the top of the frame, there are two guide bars1,2. These guide bars1,2help guide the fabric, which begins at the fabric roll dispensing bar3. The fabric roll dispensing bar3acts as a shaft for holding a roll of fabric. From the fabric roll dispensing bar3, the fabric goes above the two guide bars1,2. The fabric roll dispensing bar3itself may be rotatable, but does not have to if it holds a fabric roll which has a hollow center with a diameter larger than the diameter of the fabric roll dispensing bar3. This fabric roll dispensing bar is ideally removable, to more easily slide in and slide out a roll of fabric. Two removable and adjustable collars are present to hold the fabric roll in place. The guide bars1,2and fabric roll dispensing bar are desirable, but not essential.

Once the fabric is guided above the two guide bars1,2, the fabric makes its way between the nip rollers6,7.FIG. 1shows a preferred embodiment of the nip rollers6,7that rotate through the use of a motor, sprockets, and gears.

The front nip roller6may be adjusted to be closer or further from the rear nip roller7, to adjust the nip gap and accommodate different thicknesses of fabric. It is desirable for the nip rollers6,7should be close enough to create enough pressure on the fabric for a few reasons. One such reason is to ensure adequate impregnation of the resin into the fabric. Another such reason is so the fabric will be pulled the nip rollers6,7. In a preferred embodiment, the rear nip roller7may be adjusted to be closer or further from the front nip roller6through an adjustment means.

In a preferred embodiment, the nip rollers6,7are comprised of carbon steel, and are hollow. A large variety of other materials may be used to produce the nip rollers as known to those skilled in the art, and the nip rollers are not required to be hollow. A hollow nip roller may be more easily cooled or heated through various means, including water and steam. The cooling and/or heating of the nip rollers6,7helps to control the temperature during the impregnation of the resin into the fabric.

Above the two nip rollers6,7is a dam holder bar9. The dam holder bar9has two attachment rods that protrude towards the nip rollers. These attachment rods each hold a dam4,5at the bottom ends of the attachment rods. The dams4,5are held to the attachment rods via a spring loaded mechanism to urge the dams4,5towards the nip rollers6,7. The spring action allows for the dams4,5to apply constant pressure between the dams4,5and the nip rollers6,7. Also, by being spring loaded, these dams4,5may be more easily removed and adjusted. Alternatives to spring loading include hydraulics or a compactable rubberized backing. However, spring loading or other alternative means are not required. Gravity may be sufficient, as the rotation of the nip rollers6,7provide downward pull on the dams4,5. The dams4,5prevent the resin in the resin pool, which sits above the nip rollers6,7, from flowing off the sides. Thus, it is important for the dams4,5to provide a tight seal to prevent the resin from escaping. As such, the bottom part of the dams are shaped to be flush with the nip rollers6,7. The distance between the two dams4,5may be adjusted to accommodate the width of the fabric. There are numerous other methods known to those skilled in the art for placing dams on the nip rollers.

The fabric is impregnated with the resin as it moves through the nip rollers6,7. The fabric is moved through the apparatus by way of friction and rotation between the nip rollers6,7. In a preferred embodiment, after the fabric passes the nip rollers6,7, it may be rolled around a receiver roller8. The receiver roller is removable. The receiver roller8may rotate by use of the motor, and it is desirable for the receiver roller8to rotate at the same rate the fabric is being pushed out of the nip rollers6,7(herein referred to as operational speed). E.g., if the nip rollers6,7are pushing out the fabric at 10 ft per minute (operational speed), it is desirable for the receiver roller8to be rotating at a rate to roll up fabric at about 10 ft per minute (operational speed) as well. Rotation of the receiving roller8may be achieved by having a roller chain on the sprocket of the front nip roller6and sprocket of the receiver roller8. The receiving roller8, although useful, it not necessary.

FIG. 2illustrates a close up of the nip rollers6,7and associated gears10,11, sprockets, and chains22,23. In a preferred embodiment, the drive system is powered by a motor and motor control box. The drive system may be powered by other means, such as a hand crank or hydraulic. A sprocket from the motor (not displayed) is chained22to the sprocket of the front nip roller6, and its speed may be varied by a motor control box. The motor may be operated via a set of pedals that allow for forward or reverse movements of the motor. The pedals may be designed so that the speed of the motor is dependent on the force applied to the pedals. The pedals may be set to operate the motor only when depressed. This provides an approved safety means. Other approved safety means may include a kill button or kill switch that is easily accessible by the operator.

The front nip roller6operates the rear nip roller7through gears. The front and rear nip rollers6,7rotate in opposite direction to one another. With same sized gears attached to each nip roller6,7, the speed of rotation of both nip rollers6,7are equal. Those skilled in the art understand that there are other possible known methods for rotating the nip rollers6,7.

The front nip roller6may also have sprockets so it may be chained to sprockets of a receiver roller8. This allows for a single motor to rotate both the nip rollers6,7and the receiver roller8.

FIG. 2also illustrates a close up of the nip rollers6,7and dams20,21. The resin would be added above the nip rollers6,7, in between the dams20,21. This would result in a resin pool above the nip rollers6,7and held on the sides by the dams20,21. The dams20, may be comprised of polycarbonate or various other materials as known to those skilled in the art. There may be two different resin pools above the nip rollers6,7. When the fabric is pushed through the nip rollers6,7, it creates a division between the front nip roller6and rear nip roller7. This allows for a first resin pool to reside above the front nip roller6, and in between the two dams20,21, and the fabric. The second resin pool resides above the rear nip roller7, and in between the two dams20,21, and the fabric. Having two resin pools allows for impregnation of two different resins on either sides of the fabric. As the two resin pools are kept separated by the fabric, the distance between the dams20, should be adjusted to accommodate the exact width of the fabric. Thusly, the gap between the dams20,21and the fabric is minimized.

In other embodiments, various shapes of dams may be used to create a better seal between the dams and the fiber.FIG. 3ashows once such embodiment of a shaped dam.FIG. 3ashows a top view of two complementary dams which have a recessed section for better guiding the fabric and better preventing the two resin pools from mixing. A possible disadvantage of this shape of dam is that the fabric may not experience a good level of impregnation at the side edges, as the side edges are not fully exposed to the resin pools.FIG. 3bis a top view of another embodiment of two complementary dams which have a more progressive recesses section, resolving some of the disadvantages of the dams ofFIG. 3a.

FIG. 4illustrates an embodiment of the resin release mechanism for catalyzed resin. The resin and catalyst sit in two separate reservoirs42,43. These reservoirs42,43may be held by the apparatus or may simply sit on the ground. A positive displacement means, such as a positive displacement pump40may be utilized to move the resin from the resin reservoir42to a mixer44, such as a static mixer. The catalyst may also be moved from the catalyst reservoir43to the mixer44using a positive displacement means, such as a positive displacement pump41. The amount of resin and catalyst pumped into the mixer44should be adjustable to accommodate the proper ratio required to produce the desired catalyzed resin. For example, a common orthophthallic resin may be mixed with a catalyst such as methyl ethyl ketone. Once mixed, the catalyzed resin may be released into the resin pool.

Though not required, the release preferably occurs by fanning the catalyzed resin into the resin pool for more controlled release. This may be performed by taking the catalyzed resin, outputted from the mixer44, and releasing it into the resin pool using a spray head capable of fanning. Two separate resin release mechanism may be utilized if there are two separate resin pools on either side of the fabric. If the resin is not a catalyzed resin, then a mixer may not be required, and the resin can be pumped from the reservoir and released into the resin pool(s). The rate of release can be controlled by manually adjusting the rate of positive displacement. The rate of release may also be automatically associated with the rate the fabric is being pushed out of the nip rollers6,7(operational speed). During operation, it is desirable for the resin pools to be replenished at the same rate the resin is being depleted. Thusly, the faster the operational speed, the higher the desired rate of release. And conversely, the slower the operational speed, the lower the desired rate of release.

It may be desirable to use a dormant catalyzed resin. A dormant catalyzed resin is a resin mixed with a catalyst, where the catalyzed resin is not activated until triggered by some activation means, such as heat. In such a scenario, a post-impregnation dormant catalyst activator may be utilized. The post-impregnation dormant catalyst activator can be utilized on either side of the fabric, and is placed in a location where it can act on the fabric after impregnation (i.e., after the fabric has passed through the nip rollers6,7). If the activation required is heat, the post-impregnation dormant catalyst activator may be infrared radiation for heating. Other methods of activating a dormant catalyzed resin include light, chemicals, and mechanical force. The activation intensity post-impregnation dormant catalyst activator may be controlled manually or controlled automatically by having a control correlate the activation intensity with the operational speed. This correlation is usually a positive correlation. For example, assuming the activation means is heat, the higher the operational speed, the stronger the desired heat produced by the post-impregnation dormant catalyst activator. In another example, assuming the activation means is light, the higher the operational speed, the stronger the desired light produced by the post-impregnation dormant catalyst activator.

Referring toFIG. 1, a desirable location for a post-impregnation dormant catalyst activator is to attach it to the frame, in between the nip rollers6,7, and the receiver roller8. There may be a first post-impregnation dormant catalyst activator for the one side of the fabric, and second post-impregnation dormant activator for the other side of the fabric. These two post-impregnation dormant catalyst activator may have differing forms of activation. E.g., the first may be focused heating, and the other may be chemical spraying.

Although only referred embodiments has been described herein, many modifications will become readily apparent to one skilled in the art.