FI111467B - Ventilation arrangement in connection with a paper machine or the like - Google Patents

Description

111467

Air venting with a paper machine or similar Avluftningsarrangemang i pappermaskin eller motsvarande *

The invention relates to a deaeration system in connection with a paper machine or a similar short 5 cycle.

If a short circuit is to be constructed with a drainage tank for tap water, a large pump with a low lifting height would be required to supply the tap water to the drainage tank. However, the availability of such pumps is poor, requiring a higher lifting height for the 10 pumps.

The large feed pump between the bleed tank and the wire well could be removed from the process if the feed stream of the bleed tank could be controlled by some other means.

The matter can be traced in accordance with the invention with a small recirculation flow from the venting tank to the pump 15 for the upstream process. Recirculation flow control can be linked, for example, to the surface control of a wire well. This would also allow for a lower drainage tank and save on construction costs. The solution would not even have to give up the overload that brings stability.

In the dewatering operation according to the invention in connection with a paper machine or the like, the defrosting operation comprises a recycling line from the deaerating tank and a circulating pump therewith for recirculating a portion of the pulp / wastewater supplied to the deaerating tank. The deaeration system according to the invention is characterized by what is stated in the claims.

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The arrangement according to the invention can be used for deaerating tap water and, - * - for de-airing pulp already diluted in headbox consistency.

By a wire well, in the present invention is meant a container into which tap water is discharged from a paper machine or the like.

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The invention will now be described with reference to the accompanying drawings, in which some preferred embodiments of the invention are shown, but are not intended to be limited thereto.

5

Paper machine or the like refers to paper, board and tissue machines.

Fig. 1A shows a prior art deaerating arrangement of a papermaking machine in a short spiral.

Figure IB illustrates a first preferred embodiment of the invention in which a recycling line is connected from a bleed tank to a main line for pulp transportation between a wire well and a bleed tank.

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Figure 1C illustrates an embodiment of the invention in which a recycling line is connected from a bleed tank overflow to a main line between a wire well and a bleed tank, and in which apparatus the wire well is further provided with an overflow.

Figure ID illustrates an embodiment of the invention wherein the recycle line comprises a circulation water tank and wherein the recirculation from the water tank relative to the flow of the recycle line is directly connected to the wire well, preferably near the tap water connection.

Figure IE illustrates an embodiment of the invention in which a vortex cleaner of a vortex cleaning plant cleaning stage is mimicked in a wire well and a deaeration tank *. wherein the acceptor line of the vortex cleaner is connected to the venting tank and wherein in the device solution a recycling line derived from an overflow of the air cleaning tank comprising a recirculation pump is connected to said accepting line.

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In the prior art solution in FIG. from the tank 10 to the feed pump Po of the headbox 11 and further along the line Y to the feeder box 11. The vacuum pump V sucks the vacuum into the venting tank 10 into its tank space Dj. The upper level Ti of the pulp in the venting tank 10 is at a height of 10-18 meters above the surface water level T2 of the tap water. As shown in the figure, from the wire section (not shown in Figure 10), water is led along line 13a to the top of the wire well 12. The viscous pulp is led into the wire well via line 13b and the combined flow is led by the feed pump Pi to the vortex cleaning plant F and further from its stage Fi to the deaeration tank 10.

A problem with prior art solutions is the high lift height required for the pulp feed pump Pi and its adjustment. Such pumps are poorly available and expensive to purchase and operate.

Figures IB-IE show some preferred embodiments of the invention. Typically, in all embodiments, there is a wire well 12 and a main pulp / tap water flow line 15 between the wire well 12 and the dewatering tank 10. In the illustrated embodiments, the venting vessel 10 • € is subjected to vacuum by means of a device V, which is preferably a vacuum pump. The vacuum pump V is located in the pipeline M, which opens into the internal mass space Di of the deaeration tank 10. From space Di there is a mas-25 for the deaerated / tap water which is further vented to return line Y to headbox 11 via the downstream pump Po.

According to the invention, as shown in Fig. IB, a return flow check is formed from the venting vessel 10 to the venting vessel 10 to the inlet 15. Line 15 is located between the wire well 12 and the deaeration tank 10. In the arrangement according to the invention, there is no need for a separate pulp feed pump in the line 15 leading to the venting tank 10, but feed is provided by the pump 17 in the recycling line 16.

The recycling line 16 is connected at its upper end to the venting vessel 10 and, in the embodiment, opens into its bulk container space Di. At its other end, line 16 joins pulp / tap water main line 15.

In the solution shown in Fig. 1B, the recirculation pump 17 is adjusted according to the height level T2 of the surface of the wire well 10 12 measured by the sensor device 18. The wire well 12 itself does not need overflow; The adjustment is obtained by the sensor device 18 measured in the wire well 12 from the tap water surface height T2. The sensor device is designated by reference numeral 18 and the signal line is designated by reference numeral 19 between the sensor device and 15 of the pump 17. The venting vessel 10 itself, in the embodiment of Figure 1B, does not comprise overflow, but the pulp / tap water from the venting vessel is led to the headbox 11 of the papermaking machine along a line Y. If the deaerating tank is purged of only tap water, a thick mass 13c is introduced into the tap water, preferably for dilution before the aft feed pump Po. The thick mass is then diluted to 20 headbox densities. The aft feed pump Po is located in the pulp / tap water discharge line Y. A vacuum is provided in the internal space of the venting vessel 10, e.g.

Figure 1C illustrates an embodiment similar to Figure 1B, but in the solution of the figure, the wire well 12 comprises an overflow 20 and also the venting vessel 10 \ comprises an overflow 21. The overflow 21 is formed in connection with the bulk space Di A vacuum V, 30 located in the pipeline M which opens into the interior space of the tank 10, is formed into a vacuum inside the vacuum vessel 10.

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In connection with the overflow 21 of the venting tank 10, there is a sensor device 18 for controlling the flow (depending on the amount) of the recirculation pump 17 in the recycle line 16. The sensor 18 thus detects the flow through the overflow 21. The signal line the elevation difference between the surface water levels T1 and T2 of the tap water and the mass in the dewatering vessel 10 is 5-10 meters in height. Recirculation line 16 is connected at one end to the overflow 21 of deaeration tank 10 and mas-10 for saline / tap water to venting tank 10.

Fig. 1D otherwise illustrates an embodiment similar to Fig. 1B, but in the embodiment the solution comprises a circulating water tank 22, the circulating water line 23 consisting of an overflow drain 23a from the overflow 21 of the Using the pump 17 in the return line 23a2, the flow from the wire well 12 to the line 15 and further to the venting vessel 10 is adjusted by adjusting the pump 17 in the recycle line 23ai, 23a2 by observing the elevation T2 of the in the embodiment, there is a height difference of 5 to 10 meters between the surface T2 of the tap water in the wire well and the surface T1 of the mass in the deaeration tank. Also in this embodiment of the figure, the vacuum pump P is used to draw vacuum through the pipeline M to the internal space Di of the tank 10. The overflow 21 comprises a septum S.

From the inside of the tank 10, the tank space Dj into which the pulp is led is the return line Y, preferably via water dilution to the headbox 11.

t • *

Figure IE illustrates an embodiment of the invention in which the venting vessel 10 comprises an overflow 21 and a recirculation line 16 comprises a recirculation pump 17 which receives its control 30 based on the detection of the sensor device 18 in the overflow 21. The recycling line 16 is led from the overflow 21 of the venting vessel 10 to the line 15a2, i.e., • · 6, between the vortex cleaner 100 and the venting vessel 10 on a stage 1114677. Thus, in this embodiment, a vortex cleaning plant F, its first vortex cleaning stage F1, is provided in line 15 between the wire well 12 and the deaeration tank 10. From the wire well 12 there is a line 15ai to a vortex cleaning plant F to its step Fi and a further 5 steps Fi to a vortex cleaner 100. From the vortex cleaner 100 there is an accept line 15a2 further to the air venting tank 10. The height difference between the surface level T2 of the wire well 12 and the surface level Ti of the pulp in the deaeration tank is 10-18 meters. The wire 13 is supplied with wire water from the wire section and the pulp 10 is led to the bottom of the wire well 12, whereby the combined flow Li pumped by the pump Pi0 is led along line 15a1 to the first step Fi of the vortex cleaning plant. For purposes of illustration, only one vortex cleaner 100 of the vortex cleaning stage F1 of the vortex cleaning plant is shown by way of example.

The tap water is fed to the wire well 12 via line 13a and the thick mass through line 13b 15. Also in this embodiment of the figure, a vacuum is drawn into the interior space of the tank 10 by a vacuum pump V located in the pipeline M, which opens inside the venting vessel 10. The overflow 21 comprises a partition S. From space Di there is a return line Y to the deaerated mass. The pulp is further directed to the headbox 11 via the aft pump P0 and preferably water dilution 20 along line Y.

• r

In the device solutions according to the invention FIG. Thus, the pulp / tap water supplied from the venting vessel 10 through the recycling line 16, 23 is controlled by the feed flow of the venting vessel 10.

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In the device solutions according to the invention FIG. IB, FIG. 1C, FIG. The pressure between the ID wire well 12 and the subsequent deaeration tank 10 in the process is not increased by a pump or other process device.

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Claims (8)

A venting arrangement in connection with a paper machine or the like, the arrangement comprising a venting container (10), in which suction suppression and the venting container (10) and a wire well (12) provide a line (15) through which pulp / wire water from the wire well to the vent container (10), in which device solution pulp / wire water, from which the air is removed, is passed from the vent container (10) to an inlet carriage (11) in the paper machine or the like, which the vent air vent arrangement (10) comprises 10) a circulation line (16; 23. and in it a circulation pump (17), by means of which a portion of the pulp / wastewater supplied to the vent container (10) is circulated to the line (15) which leads pulp / wastewater to the vent container (10), or to the wire well (12), characterized in that the flow of pulp / wire water fed to the vent tank llaren (10) is regulated by directing the ring of the flow in the circulation line (16; 23). (FIG. 1B, FIG. 1C, FIG. ID, FIG. IE). Venting arrangement according to Claim 1, characterized in that the circulation line (16) is connected with one end directly to the container space 20 (Di) in the venting tank (10) and with its other end to the line (15) between the wire well (12) and the venting tank. (10). (FIG. 1B). Ventilation arrangement according to the preceding claim, characterized in that a sensor device (18) and a signal line (19) are provided, the sensor device (18) being arranged in conjunction with the wire well (12) to observe the height position (T2) of the sensor. the liquid located in the fluid well (12), the circulation pump (17) being controlled on the basis of the nozzle height (T2) of the liquid, the sensor device (18) being connected via the signal line (19) to regulate the circulation pump (17) . (FIG. 1B). 30 111467 Π Ventilation arrangement according to claim 1, characterized in that the circulation line (15) is connected with one end to a drain (21) in the vent tank (10) and with its other end to the line (15) between the wire well (12). ) and the bleed tank (10) and the circulation pump (17) provides control of a sensor device (18) in conjunction with an overflow (21) in the vent box (10), which sensor device monitors the flow to the overflow (21) and that a signal line (19) ) from the encoder device (18) is connected to the circulation pump (17) for controlling it. (FIG. 1C). Venting arrangement according to the preceding claim, characterized in that the wire well (12) comprises an overflow (20). (FIG. 1C). A venting arrangement according to claim 1, characterized in that the venting arrangement comprises a circulation line (23) and therein a circulation water container (22), the circulation pump (17) being arranged in a line (23a2) after the container. the circulation line (23a2) is connected with one end to the circulation water container (22) and with its other end to the wire well (12), advantageously to a wirewater connection (J1) thereon and the circulation pump (17) for its regulation Mn a sensor device (18) , which observes the height position (T2) of the wirewater in the wireline well (12) and that a line (23ai) Mn a overflow (21) in the vent (10) to the circulation water container (22). (FIG. ID). The venting arrangement according to claim 1, characterized in that the main line (15) for pulp / wirewater to the venting tank (10) comprises one. line section (15aj) Mn the wire well (12) to a vortex cleaning step (Fi) in a wire. * well purification plant (F), to a vortex purifier (100) in this and that the relevant line (15ai) comprises a pump (P10) and that the mn vortex purifier step (FI), 1 from the vortex purifier (100) in this guarantees an acceptance line (15a2 ) to the vent container (10) and that an overflow (21) in the vent container (10) likes a circulation line (16) comprising the circulation pump (17), which circulation line (16) is connected to the accepting line ( 15ai) and the circulation pump (17) receives its control from a sensor device (18) arranged at the overflow (21) in the vent container (10), a signal line (19) being connected to the circulation pump (17) and on the other hand, to the transducer (18), the circulation pump (17) receiving its control from the transducer (18) arranged at the overflow (21), which measures the flow rate through the overflow (21). (FIG. IE). Degreasing arrangement according to claim 1, characterized in that the pressure is not increased by a pump or some other process device between the wire well (12) and the process in the process after the subsequent decoupling container (10). • 1 «<