MXPA97001612A - Matrix for extruding a flu current - Google Patents

Abstract

The present invention relates to a matrix for extruding a fluid stream characterized in that it comprises: a housing having interior wall sections defining a chamber, the interior wall sections include a cylindrical section, the housing includes an inlet conduit in communication With the chamber and an outlet conduit in communication with the chamber, and an insert received removably in the chamber, the insert has a body portion with a central axis and a peripheral surface that controls the flow extending in an arc around the chamber. central axis, the central axis is oriented generally perpendicular to the direction of fluid flow moving through the inlet conduit to the chamber and moving through the outlet conduit away from the chamber, the insert has a first end portion and a second end portion, the body portion that is located between the end portions, both of the first end portion and the second end portion that are in detachable engagement with the wall sections of the housing and wherein at least one of the end portions includes a cylindrical surface that is integral to and engages the section cylindrical

Description

MATRIX FOR EXTINGUISHING A FLUID CURRENT BACKGROUND OF THE INVENTION 1_ ^ Field of the Invention This invention relates to an extrusion or coating matrix having a removable insert to change the flow characteristics of the extruded fluid stream. 2. Description of Related Art A variety of articles are manufactured by processes involving an extrusion or coating matrix. Some matrices, for example, are used to form thin films, bars or other elongated shapes of plastic material. Other matrices are widely used to apply a coating of fluid material to a moving fabric. An example of an article made by coating a moving fabric is an adhesive tape. Many types of adhesive tapes are made by spraying a liquid adhesive onto a plastic substrate, which serves as a backing for the tape. Other examples of articles made by REF: 24130 coating of a fabric include a photographic film, coated paper and tapes for audio, video and data storage, magnetic. Another example is a splinted / cast orthopedic tape, such as Scotchcast ™ tape or Scotchcast Plus ™ tape (both from 3M) which include a porous glass fiber backing that is coated with a water curable polyurethane resin. The application of a liquid or semi-liquid material to a moving fabric is carried out in some cases by the use of a coating matrix. The matrix receives the material under pressure from a pump or other device, and distributes the fluid material in regions across the width of the fabric as the fabric is advanced along its longitudinal axis. The die may include an outlet groove, which discharges the fluid in a belt on the fabric, or alternatively may include a series of discharge nozzles, which are arranged to distribute the fluid to various regions across the width of the fabric. Conventional coating dies usually have an inlet duct, an outlet duct and an inner chamber extending between the inlet duct and the outlet duct. The outlet conduit is relatively wide and frequently approximates the width of the fabric in cases where the matrix has a slot-like outlet to discharge a fluid belt onto the fabric. The inner chamber is also relatively wide and serves as a distributor to distribute the fluid entering from the inlet conduit to various regions of the outlet conduit. Individuals who are experts in the technique of coating and extrusion die design, sometimes refer to the "profile" provided by a particular matrix. The "profile" is a graphical representation of the flow velocity of the fluid measured at various locations across the width of the matrix outlet. For example, in some applications an array with a flat profile is desired. The flat profile indicates that the flow velocity of the fluid is the same, as long as it is measured along the width of the outlet. In other cases, a matrix having a parabolic profile is desired, which indicates that the flow velocity of the fluid is greater at the center of the matrix outlet and decreases as it approaches either side of the matrix outlet. Traditionally, many coating and extrusion dies have had a triangular shape or "hanging overlay" with a central inlet duct, a relatively wide outlet duct and an interior distributor chamber, which has a triangular shape to distribute the incoming fluid to various regions of the outlet duct. However, because the inlet duct is located directly through the center of the outlet duct, the fluid flow velocity in the central portions of the outlet duct, tends to be greater than the fluid flow velocity, near the ends of the outlet duct. Although such a profile may be suitable for some applications, it is not suitable for other applications such as, for example, when a matrix having a flat profile is desired. Many approaches have been suggested in the past to alter the profile of hanging overlay support matrices. One approach is to vary the cross-sectional area of the inner chamber (in the directions perpendicular to the fluid flow) as any end of the chamber approaches. For example, by increasing the cross-sectional area of the chamber as either end approaches, the flow velocity of the fluid near the sides of the outlet conduit may be increased. The hanging pendant support dies are typically made by machining two metal blocks to make the matrix halves detachable. The inlet duct, the outlet duct and the inner chamber are formed in one or both of the halves of the matrix. If a different profile is needed, the chamber sample is altered by disassembling the halves of the matrix and remachining one or both of the halves of the matrix. The shape of the chamber can also be altered by attaching one or more diaphragms to the side walls of the chamber to decrease the size of the chamber when desired. Unfortunately, it is often difficult to design a matrix that provides a particular profile that is achieved the first time when the matrix is put into service. In practice, a test run of a new matrix is carried out to observe its profile. After the run, the two halves of the die are disassembled and the inner chamber and / or the diaphragms are machined in an attempt to compensate for any deficiency of the profile. The matrix is then reassembled and the profile is observed again. It can be seen that the trial-and-error technique of adjusting the profile of a hanging pendant support matrix is time consuming and expensive. In addition, the profile may change when other process conditions are changed, such as the viscosity of the fluid or the total flow rate of the fluid. U.S. Patent No. 5,234,330 discloses a pendant coating support matrix having two separable matrix halves and one or more inserts that are located in an interior chamber of the matrix, when the matrix halves are assembled. The inserts vary in cross-sectional area along their length to increase or decrease the adjacent cross-sectional areas of the chamber, such that the profile of the matrix is affected. There is a continuing need in the art to improve known coating and extrusion dies, in such a way that the construction cost of the die can be reduced. There is also a need to provide a matrix that is easy to clean when necessary without undue effort. Preferably, such a matrix would be adaptable for use with a wide range of liquid and semi-liquid materials and also under various process conditions.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a die for extruding a fluid stream and comprises a housing having inner wall sections, which define a chamber. The housing includes an inlet conduit in communication with the chamber and an outlet conduit in communication with the chamber, wherein the inner wall sections include a cylindrical section. The matrix also includes an insert removably received in the chamber. The insert has a body portion with a central axis and a peripheral surface that controls the flow that extends in an arc around the central axis. The central axis is oriented generally perpendicular to the direction of fluid flow that moves through the inlet conduit to the chamber and moving through the outlet conduit away from the chamber. The insert has a first end portion and a second end portion. The body portion is located between the end portions. Both of the first end portion and the second end portion are in detachable engagement with the wall sections of the housing. At least one of the end portions includes a cylindrical surface, which is complementary to and engages the cylindrical section. Advantageously, the insert is relatively stable during operation, because both end portions are in contact with the housing. In addition, such construction avoids the need for fluid flow over the ends of the insert, which in any other form must change the flow characteristics in the inner chamber in an undesirable way. Other details of the invention are defined in the features of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional, horizontal view of a matrix constructed in accordance with the principles of the present invention; Figure 2 is a cross-sectional, side view of the matrix shown in Figure 1, taken along lines 2-2 of Figure 1; Figure 3 is a view somewhat similar to Figure 1 except that an insert of the matrix shown in FIG.

Figure 1 has been removed and another insert having a slightly different configuration is partially inserted into a matrix housing; Figure 4 is a view somewhat similar to Figure 3 except that the insert is fully seated in the chamber of the array; Figure 5 is a cross-sectional, horizontal view of a die according to another embodiment of the invention; Figure 6 is a view somewhat similar to the Figure 5, except that an insert of the matrix, illustrated in Figure 5 has been replaced with another insert having a slightly different configuration; Figure 7 is a graphic representation of the fluid discharge profile obtained by using the matrix illustrated in Figures 1 and 2; Figure 8 is a graphical representation of the fluid profile that is obtained using the matrix illustrated in Figure 4; Figures 9 and 10 are graphical representations of the fluid profiles obtained by using the matrices depicted in Figures 5 and 6, respectively; Figure 11 is a side elevational view of a die housing according to another embodiment of the invention; and Figure 12 is a plan view of an insert having a slightly different configuration, which is particularly advantageous when used with the matrix housing shown in Figure 11.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES A die 20 for extruding a fluid stream is illustrated in Figures 1 and 2 according to one embodiment of the invention and is useful for extrusion or coating applications. The die 20 includes a housing 22 made, for example, of a block of metallic material. The matrix has a cylindrical wall section 24, elongate, inner defining an elongated cylindrical chamber 26 of the housing 22. An inlet conduit 28 extends through the side of the housing 22 in a direction toward the middle, longitudinal axis of the chamber 26, as may be understood by comparing the Figures 1 and 2. The inlet conduit includes a threaded portion for connection to a rigid pipe 30. In turn, the tube 30 is coupled by a flexible or rigid pipe to a source of fluid that could be liquid or semi-liquid. The housing 22 also includes an outlet conduit 32 in communication with the chamber. The outlet conduit 32 is in the form of a rectangular groove, which extends in a direction along the length of the chamber 26 and in alignment with the longitudinal axis of the chamber 26. More particularly, a parallel reference plane and located centrally between the upper and lower walls of the housing 22, which define the outlet conduit 32 is also parallel to and passes through the central longitudinal axis of the chamber 26. The matrix 20 also includes an insert 34 that is removably received in the chamber 26. The insert 34 includes a body portion 36, which is cylindrical in the example shown in Figures 1 and 2. The insert 34 also includes a first end portion 38 connected to one end of the body portion 36 and a second end portion 40 connected to the other end of the body portion 36 spaced apart from the first end portion 38. The portions 38, 40 are either integral with the portion of body 36, or are initially separate elements that are joined (for example by machine screws) to the body portion 36. An outer surface of both of the first and second end portions 38, 40 is cylindrical and has a diameter that is slightly smaller than the diameter of the cylindrical chamber 26. For example, the chamber 26 may have a diameter of 19.1 mm (0.75 inches), while the first and second end portions 38, 40 may have a diameter of 19.0 mm (0.748) inches). The first and second end portions 38, 40 are slidably received in the chamber. The insert 34 also includes an end cap 42, which is located next to the first end portion 38 removed from the body portion 36. The end cap 42 is larger in diameter than the diameter of the chamber 26 to cover the opening of the latter. If desired, a handle can be connected to the end cap 42 to facilitate removal of the insert 34 from the chamber 26.

Optionally, a gasket (not shown) is located between the end cap 42 and a circular region of the housing 22 that surrounds the periphery of the chamber opening. Four machine screws extend through the end cap 42 and into the housing 22, to releasably hold the insert 34 in the chamber 26 and seal the end cap 42 to the housing 22. A cover 44 is also provided over the opening of the chamber 26 withdrawn from the end cap 42. The cover 44 is larger than the chamber 26 and has a flat wall surface, facing inwardly or a wall section defining the end of the chamber 26. Optionally , a joint is located between the cover 44 and a circular region of the housing 22 that surrounds the periphery of the opening of the adjacent chamber, to seal the latter from the atmosphere. The machine screws releasably attach the cover 44 to the housing 22. The body portion 36 extends along the central axis of the chamber 26 and is oriented perpendicular to the direction of the fluid flow moving through the inlet duct 28 to the chamber 26 (except for any of the located disturbances of the fluid flow near the junction of the inlet conduit 28 and the chamber 26). The central axis of the body portion 36 is also perpendicular to the direction of fluid flow that moves through the outlet conduit 32 away from the chamber 26 (except for any of the localized disturbances of fluid flow near the junction of the chamber 26 and the outlet conduit 32). While it is presently preferred that the central axis of the body portion 36 be perpendicular to the direction of fluid flow in the inlet conduit 28 and the outlet conduit 32, other orientations are also possible that are generally perpendicular (i.e. the range of 90 degrees ± 10 degrees) and within the scope of the present invention. The cylindrical peripheral surface of the body portion 36 provides fluid flow control that moves through the die 20. With such a construction, the pressure drop of the fluid flow is greatest in the center of the chamber 26 in direction along its central longitudinal axis. A graphical representation of the fluid profile is illustrated in Figure 7 for matrix 20 of Figures 1 and 2. In Figure 7, the horizontal axis represents the velocity of the fluid flow, although the vertical axis is representative of the locations a across the width of the outlet conduit 32 (ie, in directions parallel to the longitudinal axis of the chamber 26). As can be seen, the profile is generally parabolic in shape, with the highest flow that is in the middle of the outlet conduit 32 and gradual variation as any end of the outlet conduit 32 approaches. Advantageously, both of the first and second end portions 38, 40 are in firm, but separable, engagement with the section 24 of the cylindrical wall of the housing 22. As a result, both ends of the insert 34 are supported by the housing 22 and resist the oscillation as the fluid flows through the die 20. As shown in Figure 1, the width of the outlet duct 32 (ie, in the directions parallel to the longitudinal axis of the chamber 26) is equal to the distance between the second and first end portions 38, 40. In Figures 3-4, a die 120 includes a housing 22 which is the same as the housing 22 described in relation to Figures 1 and 2. However, the die 120 it has an insert 134 with a body portion 136, which is different from the body portion 36. More particularly and as can be seen by reference to Figures 3-4, the body portion has a peripheral surface that controls the flow, which includes an enlarged central region and two conical regions that become smaller in diameter as any end of the chamber 26 approaches. As the end portion 36, the central axis of the body portion 136 extends along the longitudinal, central axis of the chamber 26. Furthermore, as the body portion 36, the peripheral surface of the body portion 136 has a circular shape in the planes of reference perpendicular to the longitudinal axis of the body portion 136. As such, both of the body portions 36, 136 can be machined economically in a lathe to precise dimensions. The insert 134 also has a first end portion 138, a second end portion 140 and an end cap 142, all of which are identical to the first end portion 38, the second end portion 40 and the end cap 42 of the insert 34. As a result, a detailed description of such elements does not need to be repeated. A graphic representation of the profile provided by the array 120 is illustrated in Figure 8. As illustrated, the array 120 provides a flat profile, such that the fluid flow velocity exiting the exit conduit 32 is uniform to across the whole width. Now as can be appreciated, the present invention allows the user to obtain different profiles without replacing or disassembling the housing 22. any of the inserts 34, 134 can be removed from the chamber 26 and easily replaced with the other of the inserts 34, 134 according to is desired Figure 3 shows the step of placing the insert 134 in the housing 22. In addition, it is possible to provide a variety of inserts having body portions with other configurations, such that a variety of profiles are available. Another embodiment of the invention is illustrated in Figure 5, in which a die 220 includes a housing 222 having an inner cylindrical wall section 224, a chamber 226 and an inlet duct 228. A tube 230 is connected to the duct 228. The wall section 224, the chamber 226, the inlet duct 228 and the tube 230 are all identical to the wall section 24, the chamber 26, the inlet duct 28 and the tube 30 described in connection with the embodiment illustrated in Figures 1 / 2. An outlet duct 232 of the housing 222 is identical to the outlet duct 32 of the matrix 20, except that the downward end of the outlet duct 232 is closed by a flat wall 231. A A series of holes are drilled in the wall 231 and a nozzle 233 is fixedly secured in each hole, so that a number of separate, separate exit holes are provided. Each nozzle 233 is made of a rigid metal tube or rod having a flattened outer end. Alternatively, each nozzle 233 is a commercially available nozzle, which optionally has an adjustment for varying the flow velocity of the fluid outlet or the pattern of the discharged fluid. Separate nozzles 233 provide individual fluid streams that can, for example, be applied to a moving fabric passing adjacent matrix 220. An insert 234 of matrix 220 is removably received in chamber 226 and is identical to insert 34 described in relation to the embodiment shown in Figures 1 and 2. A cover 244, identical to the cover 44, is secured to the end of the housing 222 on one end of the chamber 226. A graphic representation of the fluid profile provided by the matrix 220 is illustrated in Figure 9. Although nozzles 233 provide separate fluid streams, currents when averaged together provide a profile that is similar to the profile illustrated in Figure 7 for the embodiment shown in Figures 1 and 2. fluid streams can touch or overlap each other, if desired as the currents mate with the fabric. In Figure 6, a die 320 includes the housing 222 described above, as well as an insert 334 that is identical to the insert 134 described in relation to the embodiment shown in Figures 3-4. Figure 10 is a graphical representation of the fluid profile obtained using matrix 320.

The fine adjustments for the matrix profiles obtained using the matrices 20, 120, 220, 320 can be carried out using conventional techniques that are known to those skilled in the art. For example, the temperature of the matrix or the fluid that enters can be changed to a temperature above or below the ambient. As another option, the die outlet conduit can be provided with a flexible flange in contact with the multiple adjustment screws distributed through the outlet conduit, such that rotation of the bolts can increase or decrease the speed of the flow in adjacent regions of the conduit. Figure 11 is a side view of a matrix housing 522 according to another embodiment of the invention. The die housing 522 includes a cylindrical chamber 526, as well as an auxiliary channel 527 extending through the housing 522 in parallel relation to the chamber 526. The channel 527 is attached to a source of hot water or other fluid, to raise the temperature of the housing 522 above the room temperature to increase the flow of fluid moving through the chamber 526. The housing 522 of the matrix includes a first metal member 529 containing the chamber 526 and the channel 527, together with a second metallic member 531 that is detachably connected to the first member 529 by four machine screws. An aligned series of separate nozzles 533 extends through the second member 531 and projects forward therefrom. An outlet conduit 532 of the die housing 522 includes the nozzles 533, as well as also a rectangular slot 535 communicating with the nozzles 533 with the chamber 526. The first member 529 includes a flange 537 for supporting the second member 531 and facilitating the mounting of the second member 531 to the first member 529. The first member 529 also includes a projection 539 for connection to a device for supporting the matrix housing 522, such as, for example, a fixed arm mounted adjacent to the fabric in movement or an arm that is movable toward or away from the fabric. The direction of the fluid flowing through an inlet conduit 528 to the chamber 526 is perpendicular to the direction of fluid flow through the outlet conduit 532 away from the chamber 526. The chamber 526 is adapted to removably receive a insert, such as inserts 34, 134, 234, 334 mentioned in the foregoing, or alternatively receiving insert 534 which is illustrated in Figure 12. Insert 534 has a body portion 536 having a central cylindrical section, a pair of cylindrical end sections and two generally truncated cone sections integrally interconnecting the center section and the end sections. The two end sections have a cross-sectional diameter larger than the center section and are each located next to the respective end portions 538, 540. The insert 534 is slidably received in the chamber 526, and includes an end cap 542 that optionally attaches to a handle. The "dog bone" shape of the body portion 536 is particularly advantageous, in achieving a generally flat fluid profile, when used in a matrix housing such as the matrix housing 522, in which the direction of flow of fluid through an inlet conduit is perpendicular to the direction of the fluid flowing through an outlet conduit. As an alternative for the machine screws for attaching the second member 531 to the first member 529, the projection 537 can be replaced with an L-shaped projection having a vertical leg and the second member 531 can have a portion that is slidably received. between the vertical leg and the remaining portions of the first member 529. The upper part of the second member 531 (observing Figure 11) in such case would be formed with a hook and a clamp attached to the first member 529, would releasably couple the hook to securely hold the second member 531 against the first member 529, such that the nozzles 533 are aligned and in communication with the slot 535. Preferably, the clamp includes a cam arm in the center that holds releasably the wire loop in engagement with the hook. The principles of the present invention will now be apparent and those skilled in the art may recognize other modifications or additions that may be employed without departing from the spirit of the invention. For example, the body portion of the insert can have an exterior surface configuration that can be selectively varied by the user during the operation. An example is an insert with a rigid, longitudinal, central rod that is surrounded by an expandable bladder. Air or fluid pressure is applied. to one or more of the bladder chambers that allows that. the configuration of the bladder surface is altered. A variety of other modifications and additions are also possible. Accordingly, the scope of the invention should be limited only by an adequate reading of the following claims and their equivalents. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, the content of the following is claimed as property.

Claims (4)

1. A die for extruding a fluid stream characterized in that it comprises: a housing having interior wall sections defining a chamber, the interior wall sections include a cylindrical section, the housing includes an inlet conduit in communication with the chamber and a conduit output in communication with the camera; and an insert received removably in the chamber, the insert has a body portion with a central axis and a peripheral surface that controls the flow extending in an arc about the central axis, the central axis is oriented generally perpendicular to the direction of the Fluid flow moving through the inlet duct into the chamber and moving through the outlet duct away from the chamber, the insert has a first end portion and a second end portion, the body portion that is located between the end portions, both of the first end portion and the second end portion that are in detachable engagement with the wall sections of the housing and in which at least one of the end portions includes a cylindrical surface that is complementary to and fits the cylindrical section.

2. The matrix according to claim 1, characterized in that the insert includes an end cap located near one of the end portions removed from the body portion, the end cap is larger than an end portion in directions perpendicular to the axis central.

3. The matrix according to claim 1, characterized in that the chamber has a generally cylindrical configuration.

4. The matrix according to claim 1, characterized in that the insert is slidably received in the chamber.