Abstract
A paper machine screen which is formed as a transverse thread-bound, multi-layer fabric. Binding transverse threads extend respectively both in an upper fabric layer and in a lower fabric layer and hereby bind the lower fabric layer to the upper fabric layer. The binding transverse threads form functional transverse thread pairs within the total repeat, the transverse threads of which alternately complete the first weave. In the total repeat, the functional transverse thread pairs in the upper fabric layer are arranged in groups of respectively two or more functional transverse thread pairs arranged directly one after another, when seen in a longitudinal direction.
Claims
1. A paper machine screen, formed as a transverse thread-bound multi-layer fabric having an upper fabric layer comprising a first weave and a lower fabric layer comprising a second weave, wherein the multi-layer fabric has a total repeat which includes: upper longitudinal threads which extend exclusively in the upper fabric layer, lower longitudinal threads which extend exclusively in the lower fabric layer, the ratio of upper longitudinal threads to lower longitudinal threads being 1:1, the lower longitudinal threads having a diameter which is greater than or equal to the diameter of the upper longitudinal threads, upper transverse threads which extend exclusively in the upper fabric layer and which are interwoven with the upper longitudinal threads, thereby partially forming the first weave, lower transverse threads which extend exclusively in the lower fabric layer and are interwoven with the lower longitudinal threads, thereby completely forming the second weave, wherein the lower transverse threads have a diameter which is greater than the diameter of the upper transverse threads, and binding transverse threads which respectively extend both in the upper fabric layer and in the lower fabric layer and hereby bind the lower fabric layer to the upper fabric layer, wherein, within the total repeat, the binding transverse threads form functional transverse thread pairs of respectively two binding transverse threads arranged directly next to each other, wherein the two binding transverse threads of a respective functional transverse thread pair alternately complete the first weave and, in doing so, respectively extend over one or more upper longitudinal threads, thereby forming an imaginary upper transverse thread, wherein the two binding transverse threads of a respective functional transverse thread pair alternately bind the lower fabric layer with the second weave completely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair extending under at least one lower longitudinal thread during its course in the lower fabric layer within the total repeat, and wherein, in the total repeat, the functional transverse thread pairs in the upper fabric layer are arranged in groups of respectively two or more functional transverse thread pairs arranged directly one after another, when seen in a longitudinal direction, wherein two successive groups are respectively separated from each other by one or two or more upper transverse threads.
2. The paper machine screen according to claim 1, wherein, in the total repeat, the functional transverse thread pairs in the upper fabric layer are arranged in groups of exactly two functional transverse thread pairs arranged directly one after another, when seen in a longitudinal direction, and/or in the total repeat in the upper fabric layer two directly successive groups are respectively separated from each other by exactly one or respectively by exactly two upper transverse threads.
3. The paper machine screen according to claim 1, wherein, in the total repeat, the functional transverse thread pairs are, also in the lower fabric layer, arranged in groups of two or more functional transverse thread pairs arranged directly one after another when seen in a longitudinal direction, wherein respectively one or two or more lower transverse threads are arranged between two successive groups of functional thread pairs.
4. The paper machine screen according to claim 3, wherein, in the total repeat, the functional transverse thread pairs are arranged in groups of exactly two functional transverse thread pairs arranged directly one after another in the lower fabric layer when seen in a longitudinal direction, and/or in the total repeat in the lower fabric layer two successive groups are respectively separated from each other by exactly two lower transverse threads.
5. The paper machine screen according to claim 1, wherein, in the total repeat, in the lower fabric layer all binding transverse threads of a respective group of functional transverse thread pairs bind the lower fabric layer to the upper fabric layer between the same two associated lower transverse threads following one another in a longitudinal direction.
6. The paper machine screen according to claim 1, wherein, in the lower fabric layer, the interspaces formed between the lower transverse threads are alternately provided and not provided with bindings by the binding transverse threads of a respective group of functional transverse thread pairs, when seen in a longitudinal direction.
7. The paper machine screen according to claim 1, wherein the first weave is a plain weave which in the longitudinal direction is formed by the upper longitudinal threads and in the transverse direction is formed by the upper transverse threads and the imaginary upper transverse threads formed by the functional transverse thread pairs.
8. The paper machine screen according to claim 1, wherein the total repeat and/or the repeat of the upper fabric layer includes 8, 10 or 12 upper longitudinal threads.
9. The paper machine screen according to claim 1, wherein the second weave is a 5-shaft weave or a 10-shaft weave in which the course of the respective lower transverse thread is repeated in a transverse direction after 5 and 10 lower longitudinal threads, respectively.
10. The paper machine screen according to claim 1, wherein the total repeat includes: 10 upper longitudinal threads, 10 lower longitudinal threads, 10 upper transverse threads, 10 lower transverse threads, and 20 binding transverse threads which form 10 functional transverse thread pairs.
11. The paper machine screen according to claim 1, wherein the total repeat includes: 10 upper longitudinal threads, 10 lower longitudinal threads, 10 upper transverse threads, 20 lower transverse threads, and 40 binding transverse threads which form 20 functional transverse thread pairs.
12. The paper machine screen according to claim 1, wherein, in the total repeat all longitudinal threads extending in the upper fabric layer are upper longitudinal threads which extend exclusively in the upper fabric layer, and/or in the total repeat all longitudinal threads extending in the lower fabric layer are lower longitudinal threads which extend exclusively in the lower fabric layer, and/or in the total repeat the upper fabric layer and the lower fabric layer are connected to each other exclusively by the binding transverse threads arranged to form functional transverse thread pairs.
13. The paper machine screen according to claim 1, wherein the upper transverse threads are made of polyester and the binding transverse threads are made of polyamide.
14. The paper machine screen according to claim 1, wherein the binding transverse threads are smaller in diameter than the lower transverse threads.
15. The paper machine screen according to claim 1, wherein, in the upper fabric layer, the total repeat comprises five groups or ten groups of functional pairs.
16. The paper machine screen according to claim 1, wherein, in the total repeat, the ratio of upper transverse threads, including functional transverse thread pairs, to lower transverse threads is greater than 1.
17. The paper machine screen according to claim 1, wherein, in the total repeat, each functional transverse thread pair forms exactly two intersections and/or wherein the intersections of all functional transverse thread pairs are distributed evenly to the upper longitudinal threads within the total repeat, so that the same number of intersections is positioned under each upper longitudinal thread.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 shows a detail of a known screen, especially of its upper fabric layer, wherein the characteristic arrangement/subunit of two successive upper transverse threads and one functional transverse thread pair, recurring on the paper side in a longitudinal direction is shown, i.e. two upper transverse threads and one functional transverse thread pair are alternately arranged one after another in a longitudinal direction on the paper side. In addition, it can be seen that a 10-shaft weave is concerned, i.e. the transverse thread course (especially the course of the binding transverse threads) is repeated after 10 upper longitudinal threads. The functional transverse thread pair forms an imaginary upper transverse thread which forms a plain weave together with both upper transverse threads and the upper longitudinal threads. The changeover positions of the next subunit (not shown) following in a longitudinal direction may be offset in a transverse direction. The characteristic subunit only includes one functional transverse thread pair.
(2) FIG. 2 shows a detail of another known screen, especially of its upper fabric layer, wherein the characteristic arrangement/subunit of one upper transverse thread and one functional transverse thread pair, recurring on the paper side in a longitudinal direction, is shown, i.e. one upper transverse thread and one functional transverse thread pair are alternately arranged one after another in a longitudinal direction on the paper side. In addition, it can be seen that a 10-shaft weave is concerned, i.e. the transverse thread course (especially the course of the binding transverse threads) is repeated after 10 upper longitudinal threads. The functional transverse thread pair forms an imaginary upper transverse thread which forms a plain weave together with the upper transverse thread and the upper longitudinal threads. The changeover positions of the next subunit (not shown) following in a longitudinal direction may be offset in a transverse direction. The characteristic subunit only contains one functional transverse thread pair.
(3) FIG. 3 shows a detail of a screen according to the invention, especially of its upper fabric layer, wherein the characteristic arrangement/subunit of two (directly) successive upper transverse threads and two (directly) successive functional transverse thread pairs, recurring on the paper side/upper side in a longitudinal direction, is shown (both upper transverse threads and both functional transverse thread pairs are respectively arranged in pairs), i.e., one pair of upper transverse threads and one pair of functional transverse thread pairs are alternately arranged one after another in a longitudinal direction on the paper side. In addition, it can be seen that a 10-shaft weave is concerned, i.e. the transverse thread course (especially the course of the binding transverse threads) is repeated after 10 upper longitudinal threads.
(4) FIG. 4 shows a detail of a screen according to the invention, especially of its upper fabric layer, wherein the characteristic arrangement/subunit of two successive upper transverse threads and two successive functional transverse thread pairs, recurring on the paper side/upper side in a longitudinal direction is shown, i.e., one pair of upper transverse threads and one pair of functional transverse thread pairs are alternately arranged one after another on the paper side. In addition, it can be seen that an 8-shaft weave is concerned, i.e. the transverse thread course (especially the course of the binding transverse threads) is repeated after 8 upper longitudinal threads.
(5) FIG. 5 shows a detail of a screen according to the invention, especially of its upper fabric layer, wherein the characteristic arrangement/subunit of two successive upper transverse threads and two successive functional transverse thread pairs, recurring on the paper side/upper side in a longitudinal direction, is shown, i.e., one pair of upper transverse threads and one pair of functional transverse thread pairs are arranged alternately one after another in a longitudinal direction on the paper side. In addition, it can be seen that a 12-shaft weave is concerned, i.e. the transverse thread course (especially the course of the binding transverse threads) is repeated after 12 upper longitudinal threads.
(6) FIG. 6 shows a detail of a screen according to the invention, especially of its upper fabric layer, wherein the characteristic arrangement/subunit of one upper transverse thread and two successive functional transverse thread pairs, recurring on the paper side/upper side in a longitudinal direction is shown, i.e., one upper transverse thread and one pair of functional transverse thread pairs are arranged alternately one after another in a longitudinal direction on the paper side. In addition, it can be seen that a 10-shaft weave is concerned, i.e. the transverse thread course (especially the course of the binding transverse threads) is repeated after 10 upper longitudinal threads.
(7) In FIGS. 3 to 6, the functional transverse thread pairs respectively form an imaginary upper transverse thread, which together with the upper transverse threads or the upper transverse thread and the upper longitudinal threads form a plain weave. The changeover positions of the next subunit (not shown) following in a longitudinal direction may be offset in a transverse direction. The respective characteristic subunit includesother than in the state of the art according to FIGS. 1 and 2two functional transverse thread pairs which are directly adjacent to each other in the longitudinal direction.
(8) FIGS. 7a and 7b show the total repeat of a multi-layer fabric serving as a paper machine screen, especially as a sheet forming screen, according to a first embodiment of the invention, especially the courses of all transverse threads of the total repeat with respect to the lower and upper longitudinal threads.
(9) FIG. 8 shows a top view of the upper fabric layer of the total repeat. This corresponds at the same time to a top view of the weave repeat of the upper fabric layer.
(10) FIG. 9 shows a top view of the lower fabric layer of the total repeat. This corresponds at the same time to a top view of the weave repeat of the lower fabric layer.
(11) FIGS. 10a to 10d show the total repeat of a multi-layer fabric serving as a paper machine screen, especially as a sheet forming screen, according to a second embodiment of the invention, in particular the courses of all transverse threads of the total repeat with respect to the lower and upper longitudinal threads.
(12) FIG. 11 shows a top view of the upper fabric layer of the total repeat. This corresponds at the same time to a top view of the repeat of the upper fabric layer.
(13) FIG. 12 shows a top view of the lower fabric layer of the total repeat. This corresponds at the same time to a top view of eight weave repeats of the lower fabric layer directly adjacent to each other.
DETAILED DESCRIPTION OF THE DRAWINGS
(14) Hereinafter, the invention shall be explained in more detail by means of two exemplary embodiments with reference to the drawings.
(15) However, first of all, a characteristic feature of the screen/fabric according to the invention is to be explained in more detail with reference to FIGS. 1 to 6.
(16) FIG. 1 shows a detail/section of the upper fabric layer of a known screen, which illustrates the characteristic subunit of two successive upper transverse threads and one functional transverse thread pair, always recurring on the paper side when seen in a longitudinal direction (here for a 10-shaft plain weave, i.e. the transverse thread course is repeated after 10 longitudinal threads and the transverse threads form a plain weave together with the longitudinal threads). I.e., according to this known screen, one pair of upper transverse threads and one functional transverse thread pair are alternately arranged on the paper side in a longitudinal direction.
(17) FIG. 2 shows a detail/section of the upper fabric layer of another known screen, which illustrates the characteristic subunit of one upper transverse thread and one functional transverse thread pair, always recurring on the paper side when seen in a longitudinal direction (again for a 10-shaft plain weave). I.e., according to this known screen, one upper transverse thread and one functional transverse thread pair are alternately arranged on the paper side in a longitudinal direction.
(18) FIGS. 3 to 5 each show a detail/section of a screen according to the invention, especially of its upper fabric layer, which illustrates the respective characteristic subunit of two successive upper transverse threads and two successive functional transverse thread pairs, recurring on the paper side/upper side in a longitudinal direction. I.e., according to these fabrics/screens according to the invention, one pair of upper transverse threads and one pair of functional transverse thread pairs are alternately arranged one after another on the paper side in a longitudinal direction. FIG. 3 shows this for the case of a 10-shaft plain weave, FIG. 4 for the case of an 8-shaft plain weave, and FIG. 5 for the case of a 12-shaft plain weave.
(19) FIG. 6 shows a detail/section of a screen according to the invention, especially of its upper fabric layer, wherein the characteristic subunit of one upper transverse thread and two successive functional transverse thread pairs, recurring on the paper side/upper side in a longitudinal direction, is shown (by way of example for a 10-shaft plain weave). I.e., one upper transverse thread and one pair of functional transverse thread pairs are alternately arranged one after another on the paper side in a longitudinal direction.
(20) Other than in the state of the art according to FIGS. 1 and 2, where functional transverse thread pairs are arranged individually in a longitudinal direction on the paper side and are separated from each other by upper transverse threads (or rather where the characteristic subunit only contains one functional transverse thread pair), the functional transverse thread pairs according to the invention are arranged in groups separated from each other by upper transverse threads, for example in pairs, on the paper side (or rather the characteristic subunit contains functional transverse thread pairs which are directly adjacent to each other).
(21) FIGS. 7a, 7b, 8 and 9 show the total repeat of a multi-layer fabric according to a first embodiment of the invention, serving as a paper machine screen, especially as a sheet forming screen, wherein FIGS. 7a and 7b show the courses of all transverse threads (upper, lower and binding transverse threads) of the total repeat with respect to the lower and upper longitudinal threads, wherein FIG. 8 shows a top view of the upper fabric layer (and the upper side, respectively) of the total repeat, and wherein FIG. 9 shows a top view of the lower fabric layer of the total repeat. The threads extending from the left-hand side to the right-hand side in the Figures are transverse threads (for example weft threads), and the threads extending bottom-up in the Figures are longitudinal or machine direction threads (for example warp threads).
(22) As can be seen in the Figures, the multi-layer fabric has an upper fabric layer comprising a first weave (see FIG. 8; for example, the upper fabric layer forms the so-called paper side of the screen), and a lower fabric layer comprising a second weave (see FIG. 9; for example, the lower fabric layer forms the so-called machine side of the screen). These two fabric layers are connected to each other or held together by (binding) transverse threads (see FIGS. 7a, 7b and 9), so that the fabric can be referred to as transverse thread-connected or transverse thread-bound fabric. For example, the upper fabric layer and the lower fabric layer in the total repeat, especially in the entire multi-layer fabric, may be connected to each other exclusively by the binding transverse threads arranged to form functional transverse thread pairs, i.e., for example, may be free from separate binder threads and/or binding longitudinal threads.
(23) The multi-layer fabric is formed by (for example consists of or is exclusively formed by) a total repeat (repeating in the fabric), which includes the following types of threads: upper longitudinal threads 1, 3, 5, 7, 9, etc., which extend exclusively in the upper fabric layer, lower longitudinal threads 2, 4, 6, 8, 10, etc., which extend exclusively in the lower fabric layer, upper transverse threads 101, 102, 109, 110, 117, 118, 125, 126, etc., which extend exclusively in the upper fabric layer and are interwoven with the upper longitudinal threads, thereby partially forming the first weave, lower transverse threads 103, 108, 111, 116, 119, 124, 127, etc., which extend exclusively in the lower fabric layer and are interwoven with the lower longitudinal threads, thereby completely forming the second weave, and binding transverse threads 104 to 107, 112 to 115, 120 to 123, etc., which extend each both in the upper fabric layer and in the lower fabric layer (i.e., these threads interchange between the two fabric layers), and thereby bind the lower fabric layer to the upper fabric layer.
(24) The ratio of upper longitudinal threads 1, 3, 5, 7, 9, etc. to lower longitudinal threads 2, 4, 6, 8, 10, etc. is 1:1. As can be seen in the Figures, the ratio of upper longitudinal threads to lower longitudinal threads may, for example, be 10:10 (alternatively, for example, 12:12 or 8:8) in the total repeat. I.e., the course of the binding threads of a respective transverse thread pair (with respect to the lower and upper longitudinal threads) may be repeated in a transverse direction after 8, 10 or 12 upper longitudinal threads.
(25) The lower longitudinal threads 2, 4, 6, 8, 10, etc. have a diameter which is greater than or equal to the diameter of the upper longitudinal threads 1, 3, 5, 7, 9, etc. As can be seen in the Figures, upper and lower longitudinal threads may, for example, be equal in diameter. The total repeat and especially the entire fabric may be formed in the longitudinal direction exclusively using upper and lower longitudinal threads. I.e., all longitudinal threads extending in the upper fabric layer in the total repeat, especially in the entire multi-layer fabric, can be upper longitudinal threads which extend exclusively in the upper fabric layer. Moreover, all longitudinal threads extending in the lower fabric layer in the total repeat, especially in the entire multi-layer fabric, can be lower longitudinal threads which extend exclusively in the lower fabric layer.
(26) As can be seen in FIGS. 8 and 9, the lower transverse threads 103, 108, 111, 116, 119, 124, 127, etc. have a diameter which is greater than the diameter of the upper transverse threads 101, 102, 109, 110, 117, 118, 125, 126, etc. I.e., the lower transverse threads are formed to be thicker than the upper transverse threads. The lower side of the screen coming into contact with the paper machine can be configured to be robust by means of the thicker lower transverse threads, whereas the upper side of the screen coming into contact with the fiber suspension can be configured to be fine by means of the thinner upper transverse threads. The binding transverse threads 104 to 107, 112 to 115, 120 to 123 are, for example, also formed to be thinner than the lower transverse threads, and, in addition, have for example the same diameter as the upper transverse threads, so that the imaginary upper transverse thread formed by the respective functional pair fits well into the weave pattern of the upper weave. Due to the fact that the lower longitudinal threads and the lower transverse threads do not change into the upper layer, the fine paper side is not interfered with by the robust lower threads. The comparatively thin, binding transverse threads which change into the lower layer, interfere with the lower weave only insignificantly. Moreover, the comparatively thick lower transverse threads project further downwards than the binding transverse threads during their presence in the lower layer, whereby the binding transverse threads are shielded by the lower transverse threads and protected against wear.
(27) The ratio of upper transverse threads to lower transverse threads may, for example, be 1:1, for example 10:10. Under consideration of the functional transverse thread pairs or rather the imaginary upper transverse threads formed thereby, the ratio (upper transverse threads+imaginary upper transverse threads)/lower transverse threads is, for example, 2:1, for example 20:10. In other words, the paper side/upper side of the screen may be formed to be finer than the comparatively coarse machine side/lower side of the screen. In this respect, the functional transverse thread pairs are associated with/assigned to the upper fabric layer, since they contribute to forming the first weave there, whereas they only serve for binding in the lower fabric layer. The ratio of upper transverse threads to functional pairs may, for example, be 1:1, for example 10:10. The upper transverse threads may, for example, be made of polyester, and the binding transverse threads may, for example, be made of polyamide.
(28) As can be seen especially in FIG. 8, the binding transverse threads form so-called functional transverse thread pairs 104+105, 106+107, 112+113, etc. from/of respectively two binding transverse threads directly arranged next to each other within the total repeat. Both binding transverse threads of a respective functional transverse thread pair alternately/in turns complete the first weave, thereby forming an imaginary uninterrupted upper transverse thread, and, in doing so, respectively extend over one or more upper longitudinal threads. Thereby (by the changeover), so-called changeover or cross positions are formed underneath an associated longitudinal thread, which are marked with an x in FIG. 8 and at which one thread of a pair changes to the upper side and the other thread of the pair changes to the lower side. As can be seen in FIG. 8, each functional transverse thread pair may, for example, have/form exactly two changeover positions per total repeat.
(29) For example, the changeover positions/intersections of all functional pairs may be evenly distributed to the upper longitudinal threads within the total repeat, for example two changeover positions being allotted to every upper longitudinal thread. For example, the two changeover positions of a respective pair may rise through the total repeat with a pitch of by 3 upper longitudinal threads to the left. The functional pair of the next total repeat (in a longitudinal direction above the repeat shown) following the functional pair 138+139 then has a course (including the changeover positions) which is identical to that of the functional pair 104+105. Both binding transverse threads of a respective functional transverse thread pair alternately bind the lower fabric layer with the second weave completely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair extending under at least one lower longitudinal thread during its course in the lower fabric layer within the total repeat (for example exactly one lower longitudinal thread, as shown in FIG. 9). In the total repeat, the functional transverse thread pairs are arranged in groups A to E of respectively two or more functional transverse thread pairs arranged directly one after another in the upper fabric layer when seen in a longitudinal direction (for example arranged in pairs, as shown in FIG. 8), two successive groups A to D respectively being separated from each other by one or two or more upper transverse threads (for example by exactly two upper transverse threads, as shown in FIG. 8).
(30) I.e., as shown in FIG. 8, in the total repeat, in the upper fabric layer, the functional transverse thread pairs may, when seen in a longitudinal direction, for example be arranged in groups A to E of exactly two functional transverse thread pairs (arrangement in pairs) directly arranged one after another, wherein two successive groups are respectively separated from each other by exactly two upper transverse threads. In other words, one pair of upper transverse threads and one pair of functional transverse thread pairs are alternately arranged one after another in a longitudinal direction in the total repeat on the upper side. The total repeat may include, for example, altogether five groups A to E on the upper side.
(31) As shown in FIG. 9, in the total repeat, the functional transverse thread pairs 104+105, 106+107, etc. may, for example, also be arranged in groups A to E of two or more functional transverse thread pairs arranged directly one after another in the lower fabric layer, when seen in a longitudinal direction (for example arranged in pairs, as shown in FIG. 9), wherein respectively one or two or more lower transverse threads are arranged between two successive groups of functional transverse thread pairs (for example exactly two lower transverse threads, as shown in FIG. 9).
(32) I.e., as shown in FIG. 9, in the total repeat, in the lower fabric layer, the functional transverse thread pairs may be arranged, for example, in groups of exactly two directly successive functional transverse thread pairs (arrangement in pairs), when seen in a longitudinal direction, two successive groups respectively being separated from each other by exactly two lower transverse threads. The total repeat may, for example, include altogether five groups A to E on the lower side.
(33) In other words, in the total repeat, in the lower fabric layer, all binding transverse threads of a respective group of functional transverse thread pairs may bind the lower fabric layer to the upper fabric layer between the same two associated lower transverse threads following one another in a longitudinal direction. For example, the transverse threads 104 to 107 bind between the two lower transverse threads 103 and 108, and the transverse threads 112 to 115 bind between the two lower transverse threads 111 and 116.
(34) As shown in FIG. 9, the interspaces formed between the lower transverse threads may alternately be provided/occupied and not provided/non-occupied with bindings by the binding transverse threads of a respective group of functional transverse thread pairs in the lower fabric layer when seen in a longitudinal direction.
(35) As shown in FIG. 9, each binding transverse thread may extend under/bind another lower longitudinal thread in the lower fabric layer within a respective group of functional transverse thread pairs.
(36) As shown in FIG. 8, the first binding may, for example, be a plain weave which in a longitudinal direction is formed by the upper longitudinal threads and in a transverse direction is formed by the upper transverse threads and the imaginary upper transverse threads formed by the functional transverse thread pairs. A plain weave is particularly advantageous for the paper side and the sheet forming. However, other weaves are also possible for the paper side.
(37) As can be seen in FIG. 9, the second weave may be a 10-shaft weave where the course of the respective lower transverse thread 103, 108, 111, 116, etc. is repeated in a transverse direction after 10 lower longitudinal threads 2, 4, 6, 8, 10, 12, etc. The course of the respective transverse thread is, for example, above two successive lower longitudinal threads and then under eight successive lower longitudinal threads (when seen from above; in this respect, one counts over the edge, i.e. the lower longitudinal thread 2 follows the lower longitudinal thread 20).
(38) As can be seen in FIG. 9, this transverse thread course may extend with a pitch of three longitudinal threads to the left bottom-up through the total repeat and the repeat of the lower side, respectively. The lower transverse thread (not shown) of the abutting repeat (abutting on the upper side) following the lower transverse thread 140 then has a course which is identical to that of the lower transverse thread 103.
(39) As can be seen in FIG. 9, exactly two binding transverse threads may extend under each lower longitudinal thread or each lower longitudinal thread may be bound in by exactly two binding transverse threads in the total repeat (and the repeat of the lower side). For example, the lower longitudinal thread 2 is bound-in by the transverse threads 114 and 136. As can be seen in FIG. 9, the binding positions of a respective functional pair may rise with a pitch of three longitudinal threads to the left through the total repeat (and the repeat of the lower side).
(40) The screen or rather the fabric according to the first embodiment belongs to the initially described group of transverse thread-bound fabrics, especially to the group of fabrics which are connected by functional transverse thread pairs, which provide a virtually uninterrupted structural upper transverse thread on the upper side, and has the advantage of a reduced number of transverse threads when compared to a transverse thread-bound fabric, in the total repeat of which there are no upper transverse threads on the upper side (but only functional transverse thread pairs). Moreover, the screen or rather the fabric of the first embodiment has the advantage of a reduced tendency of marking when compared to a transverse thread-bound fabric, in the total repeat of which there are no upper transverse threads on the upper side, since the upper transverse threads bring about a fabric balance (for example, the fabric or rather the upper longitudinal threads are pressed upwards more strongly by the upper transverse threads than by the functional transverse thread pairs which form changeover positions).
(41) Moreover, the screen or rather the fabric of the first embodiment also has the advantage of a reduced tendency to marking when compared to a transverse thread-bound fabric, in the total repeat of which an upper transverse thread and a functional transverse thread pair are alternately arranged on the upper side in a longitudinal direction, since one upper longitudinal thread in two is exclusively supported by functional pairs in the latter. This can be breached/avoided by arranging the functional pairs in pairs with two upper transverse threads arranged therebetween, in which case every upper longitudinal thread is supported by upper transverse threads (at least in portions). Due to the ratio of upper transverse threads to functional pairs of 1:1 on the upper side, a reliable binding of the lower side or rather a stable layer connection can be ensured in addition, i.e. sufficient binding points can be provided for a layer connection. For example, an increase in the number of binding points for a layer connection per fiber support index (FSI according to Beran) can be achieved on the paper side when compared to the state of the art according to FIG. 1.
(42) FIGS. 10a to 10d, 11 and 12 show the total repeat of a multi-layer fabric according to a second embodiment of the invention, serving as a paper machine screen, for example a sheet forming screen, wherein FIGS. 10a to 10d show the course of the respective transverse thread with respect to lower and upper longitudinal threads in the total repeat, FIG. 11 shows a top view of the upper fabric layer and the upper side of the total repeat, respectively, and wherein FIG. 12 shows a top view of the lower fabric layer of the total repeat. The threads extending from the left-hand side to the right-hand side in the Figures are transverse threads (for example weft threads), and the threads extending bottom-up in the Figures are longitudinal threads or machine direction threads (for example warp threads).
(43) As can be seen in the Figures, analogously to the first embodiment, the multi-layer fabric has an upper fabric layer comprising a first weave (see FIG. 11) and a lower fabric layer comprising a second weave (see FIG. 12). These two fabric layers are interconnected or held together by binding transverse threads (see FIGS. 10a to 10d), so that the fabric can be referred to as a transverse thread-bound fabric. For example, the upper fabric layer and the lower fabric layer may be interconnected exclusively by the binding transverse threads arranged to form functional transverse thread pairs, i.e., for example, may be free from separate binder threads, in the total repeat, for example in the entire multi-layer fabric.
(44) The multi-layer fabric is formed by (for example exclusively formed by) a total repeat (repeating in the fabric) which includes the following types of threads: upper longitudinal threads 1, 3, 5, 7, 9, etc., which extend exclusively in the upper fabric layer, lower longitudinal threads 2, 4, 6, 8, 10, etc., which extend exclusively in the lower fabric layer, upper transverse threads 404, 411, 418, 425, etc., which extend exclusively in the upper fabric layer and which are interwoven with the upper longitudinal threads, thereby partially forming the first weave, lower transverse threads 403, 405, 410, 412, 417, 419, etc., which extend exclusively in the lower fabric layer and which are interwoven with the lower longitudinal threads, thereby completely forming the second weave, and binding transverse threads 406 to 409, 413 to 416, 420 to 423, 427 to 430, etc., which each extend both in the upper fabric layer and in the lower fabric layer (i.e., these threads change between both fabric layers), and thereby bind the lower fabric layer to the upper fabric layer.
(45) The ratio of upper longitudinal threads to lower longitudinal threads is, analogous to the first embodiment, 1:1. As can be seen in the Figures, the ratio of upper longitudinal threads to lower longitudinal threads may, for example, be 10:10.
(46) The lower longitudinal threads have a diameter that is greater than or equal to the diameter of the upper longitudinal threads. As can be seen in the Figures, upper and lower longitudinal threads may, for example, be equal in diameter. The total repeat and, for example, the entire fabric, may, for example, be free from binding longitudinal threads, i.e. may be formed in the longitudinal direction exclusively by upper and lower longitudinal threads. I.e., in the total repeat, for example in the entire multilayer fabric, all longitudinal threads extending in the upper fabric layer may be upper longitudinal threads, which extend exclusively in the upper fabric layer. Moreover, in the total repeat, for example in the entire multi-layer fabric, all longitudinal threads extending in the lower fabric layer may be lower longitudinal threads, which extend exclusively in the lower fabric layer.
(47) As can be seen in the Figures, the lower transverse threads have a diameter which is greater than the diameter of the upper transverse threads, analogously to the first embodiment. I.e., the lower transverse threads are formed to be thicker than the upper transverse threads. The binding transverse threads are, for example, also formed to be thinner than the lower transverse threads and, in addition, have, for example the same diameter as the upper transverse threads.
(48) The ratio of upper transverse threads to lower transverse threads may, for example, be 1:2, for example 10:20. If one considers the functional transverse thread pairs or the imaginary upper transverse threads formed thereby, the ratio of (upper transverse threads+imaginary upper transverse threads)/lower transverse threads is 3:2, for example 30:20. In this respect, the functional transverse thread pairs are assigned to the upper fabric layer, as they contribute to forming the first weave there, whereas they only serve for binding in the lower fabric layer. Thus, the upper side can be formed to be finer than the relatively coarse lower side.
(49) The ratio of upper transverse threads to functional pairs may, for example, be 1:2, for example 10:20. Hereby, the number of bindings can be increased when compared to the first embodiment as well as to the state of the art according to FIGS. 1 and 2. The upper transverse threads may, for example, be made of polyester, and the binding transverse threads may, for example, be made of polyamide.
(50) As can be seen in particular in FIG. 11, the binding transverse threads form so-called functional transverse thread pairs of respectively two binding transverse threads arranged directly next to each other within the total repeat, analogously to the first embodiment. Both binding transverse threads of a respective functional transverse thread pair alternately complete the first weave, thereby forming an imaginary, uninterrupted upper transverse thread, and, in doing so, respectively extend above one or more upper longitudinal threads. Thereby, so-called changeover or crossing positions are formed underneath an associated longitudinal thread, which in FIG. 11 are partially marked with an x and at which one thread of a pair changes to the upper side and the other thread of the pair changes to the lower side. As can be seen in FIG. 11, each functional transverse thread pair may, for example, have/form exactly two changeover positions per total repeat. The changeover positions of all functional pairs may be distributed evenly to the upper longitudinal threads within the total repeat; in this regard, for example, four changeover positions may be allotted to each upper longitudinal thread. The functional pair (not shown) of the next total repeat (in a longitudinal direction above the repeat shown), following the functional pair 469+470, has a course (including the changeover positions) which is identical to that of the functional pair 401+402. Both binding transverse threads of a respective functional transverse thread pair alternately bind the lower fabric layer with the second weave entirely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair extending under at least one lower longitudinal thread during its course in the lower fabric layer within the total repeat (for example exactly one lower longitudinal thread, as shown in FIG. 12). In the total repeat, the functional transverse thread pairs are arranged in groups A to J of two or more functional transverse thread pairs arranged directly one after another in the upper fabric layer when seen in a longitudinal direction (for example arranged in pairs, as shown in FIG. 11; in this respect, one counts over the edge with respect to the pair J), wherein two successive groups A to J are respectively separated from each other by one or two or more upper transverse threads (for example by exactly one upper transverse thread, as shown in FIG. 11).
(51) I.e., as shown in FIG. 11, for example the functional transverse thread pairs may be arranged in groups A to J of exactly two functional transverse thread pairs arranged directly one after another in the upper fabric layer when seen in a longitudinal direction in the total repeat (arrangement in pairs), two successive groups respectively being separated from each other by exactly one upper transverse thread. In other words, one upper transverse thread and one pair of functional transverse thread pairs are alternately arranged one after another in a longitudinal direction on the upper side in the total repeat. The total repeat may include, for example, altogether ten groups A to J on the upper side.
(52) As shown in FIG. 12, the functional transverse thread pairs in the total repeat may, for example, be arranged in groups A to J of two or more functional transverse thread pairs arranged directly one after another also in the lower fabric layer when seen in a longitudinal direction (for example arranged in pairs, as shown in FIG. 12), wherein respectively one or two or more lower transverse threads are arranged between two successive groups of functional transverse thread pairs (for example exactly two lower transverse threads, as shown in FIG. 12).
(53) For example, all binding transverse threads of a respective group of functional transverse thread pairs in the total repeat may bind the lower fabric layer to the upper fabric layer in the lower fabric layer between the same two associated lower transverse threads following one another in the longitudinal direction. For example, the transverse threads 406 to 409 bind between the two lower transverse threads 405 and 410, and the transverse threads 413 to 416 bind between the two lower transverse threads 412 and 417.
(54) As shown in FIG. 12, the interspaces formed between the lower transverse threads in the lower fabric layer, when seen in a longitudinal direction, may alternately be provided/occupied and not be provided/non-occupied with bindings by the binding transverse threads of a respective group of functional transverse thread pairs.
(55) As shown in FIG. 12, each binding transverse thread within a respective group of functional transverse thread pairs may extend under another lower longitudinal thread in the lower fabric layer.
(56) As shown in FIG. 11, the first weave may, for example, be a plain weave which in a longitudinal direction is formed by the upper longitudinal threads and in a transverse direction by the upper transverse threads and the imaginary upper transverse threads formed by the functional transverse thread pairs. However, other weaves are possible for the paper side as well.
(57) As can be seen in FIG. 12, the second weave may be a 5-shaft weave in which the course of the respective lower transverse thread 403, 405, 410, 412, etc. is repeated in a transverse direction after 5 lower longitudinal threads 2, 4, 6, 8, 10, 12, etc. The course of the respective transverse thread is, for example, over one lower longitudinal thread and then under four successive lower longitudinal threads (when viewed from above; in this respect, one counts over the edge, i.e. the lower longitudinal thread 2 follows the lower longitudinal thread 20). As can be seen in FIG. 12, this transverse thread course may extend with a pitch of two longitudinal threads to the right bottom-up through the total repeat and the repeat of the lower side, respectively. The lower transverse thread 419 has the same course as the lower transverse thread 419 (and the lower transverse threads 438 and 454). In a transverse direction, the course of the transverse thread 403 is repeated starting from the sixth lower longitudinal thread from the left-hand side (=longitudinal thread 12). Thus, FIG. 12 shows altogether 8 lower weave repeats.
(58) As can be seen in FIG. 12, in the total repeat, each lower longitudinal thread may be bound-in by exactly four binding transverse threads or exactly four binding transverse threads may extend under each lower longitudinal thread. For example, the lower longitudinal thread 2 is bound-in by transverse threads 408, 413, 444 and 449.
(59) Just like the screen of the first embodiment, the screen or fabric of the second embodiment belongs to the initially described group of transverse thread-bound fabrics, especially to the group of fabrics which are connected by functional transverse thread pairs which on the upper side provide a virtually uninterrupted structural upper transverse thread, and, when compared to a transverse thread-bound fabric, in the total repeat of which there are no upper transverse threads on the upper side (but only functional transverse thread pairs), has the advantage of a reduced number of transverse threads. Moreover, the screen or fabric of the second embodiment has the advantage of a reduced tendency to marking, when compared to a transverse thread-bound fabric, in the total repeat of which there are no upper transverse threads on the upper side, as the upper transverse threads bring about a fabric balance. In addition, the screen or fabric according to the second embodiment has the advantage of a reduced tendency to marking also when compared to a transverse thread-bound fabric, in the total repeat of which one upper transverse thread and one functional transverse thread pair are alternately arranged on the upper side in a longitudinal direction, as every second upper longitudinal thread is exclusively supported by functional pairs in the latter. This can be breached/avoided by the arrangement in pairs of the functional pairs with an upper transverse thread arranged therebetween, in which case every upper longitudinal thread is supported (at least in part/in sections) by upper transverse threads. Due to the ratio of upper transverse threads to functional pairs of 1:2 on the upper side, a reliable binding of the lower side and/or a stable layer connection can be ensured in addition, i.e. sufficient binding points can be provided for the layer connection. For example, an increase in the number of binding points for a layer connection per fiber support index (FSI according to Beran) can be achieved on the paper side when compared to the state of the art according to FIGS. 1 and 2.
(60) Hereinafter, calculations regarding the number of binding points for layer connection per fiber support index (FSI according to Beran) on the paper side are provided in the form of a table.
(61) TABLE-US-00001 According to the Parameter Unit Prior Art Invention Paper side FIG. 1 FIG. 3 according to . . . Warp number in the 1/cm 33.0 upper fabric Warp diameter in mm 0.13 the upper fabric Fiber support 1/cm 36.0 relevant weft threads Physically existing 1/cm 48.8 54.0 weft threads in the upper fabric Fiber support index 1 177.8 (FSI) Binding points .sup.1/cm.sup.2 79.2 118.8 Paper side FIG. 2 FIG. 6 according to . . . Warp number in the 1/cm 33.0 upper fabric Warp diameter in mm 0.13 the upper fabric Fiber support 1/cm 36.0 relevant weft threads Physically existing 1/cm 54.0 60.0 weft threads in the upper fabric Fiber support index 1 177.8 (FSI) Binding points .sup.1/cm.sup.2 118.8 158.4
