METHOD FOR TRANSFER OF MATERIALS TRANSPORTABLE BY LIQUIDS SUCH AS FIBRE MATERIALS

Abstract: Method and device to transfer materials transportable with a liquid between various treatment stages, preferably from digesting (10-16) to a subsequent treatment (38) by means of circuits of circulating liquid. Material from one or several discontinuous treatment steps (10-16) are supplied to a subsequent continuous treatment step the material being fed into the continuous step (38) by displacement by means of a liquid portion (36) withdrawn from the said step.

Description: Method for Transfer of Materials Transportable by Liquids Such as Fibre Materials. The present invention is concerned with a method of transfer of fibre material from one circuit of circulating liquid to another, where the fibre material is transported via circuit lines connected to a rotary feed valve. For coupling together various treatment vessels in processes for treatment of fibre materials it is known to use rotary feed valves for the transfer of the material . In this connection, the transfer is effected by the rotary feed valve having a rotor formed with one or several pockets which rotor is brought into various positions where connec¬ tion is established between circuit lines connected to the vessels. The object of the present invention is to make avail¬ able a method of the said kind which permits to couple several discontinuously operated treatment vessels with a continuous process so as to obtain the greatest possible yield from the process. This is achieved by endowing the method of the invention with the characteristic features stated in the appended claims. The invention whall hereinafter be described nearer in conjunction with the appended drawing, which illustrates an embodiment of a system in which the method of the invention is applied. The figure shows di agrammati cal ly an overall view of a digester house with a rotary feed valve attached therebehind for transfer of fibre material from the digesters to a detached washing vessel . In the figure, 10, 12, 14 and 16 denote treatment vessels for chips material , preferably digesters, into which the material is fed at the top in a hopper not labelled nearer and is discharged at the bottom upon finished treatment. OMPI ^&?NAT1P5> The digesters 10-16 are of the so-called discontinuous type, i.e. the material is discharged in batches. According to the invention, the bases of the digesters are by lines 18, 20, respectively coupled together in pairs and by a common line 22 connected to an outlet of a rotary feed valve 24. This rotary feed valve has in the shown embo¬ diment six outlets as is described nearer in the Swedish- patent application 7609782-3. The line which is connected to the rotary feed valve 24 from the outlet line 22 is denoted 26. For -the sake of simplicity it is assumed in the subse¬ quent description that the -rotary feed valve 24 has one pock only which thus in the shown embodiment will take three positions of operation. In the first position, the pocket stands vertically and thus connects the line 26 from the digesters 10-16 with the line 28 which starts- from the diametrically opposed side of the rotary feed valve 24. As is disclosed in the aforecited patent application, the housing of the rotary feed valve is at the outlet side towards the line 28 provided with a screen, and when the pocket takes the aforestated first posi tion fibre material and cooking liquor will thus be fed from the line 26 into the pocket of the rotary feed valve 24, whereby the pocket is filled with fibre material and cooking liquor whereas the liquor content of the pocket from the third position - see more below - flows out -through the scre and into the line 28 which is equipped with a pump not de¬ noted more specifically. The liquor drawn off into the line 28 may partly be returned through lines 30, 32 to the digesters, and partly through a line 34 to further treatment as will be described more below. The rotary feed valve 24 which rotates in clockwise direction, will thereupon bring its pocket into a second position where a circuit line 36 from the detached washing vessel 38 located therebehind is connected with a circuit line 40 equipped with a pump not labelled nearer. In this position, possible remainder of cooking liquor is displaced -Bl3 EA ( 0- -PI WIPO 4&ftNATlO " § by washing liquor which is suppled -in the line 36, the cooking liquor flowing out into the line 40 which is connected to a line 42 leading to the line 34 which also contains cooking liquor. In the line 34, there is thus a flow of both cooking liquor from the discontinuous treat¬ ment and washing liquid from the continuous treatment. In the third position of the rotary feed valve, the line 40 is connected to a line 44 which is attached to the top of the washing vessel 38. Hereunder, the liquid ' supplied through the line 40 will displace fibre material and liquor in the rotary valve into the washing vessel 38 through the line 44, while simultaneously the pocket of the rotary valve 24 is filled with liquid from the continuous treatment stage. From the washing vessel 38 the fibre material is removed through a line 46 to further treatment, for example refining and/or treatment with oxygen gas, a treatment in 2 steps, which is described nearer in the Swedish patent application 7614754-5. Possible exhaust liquid from the further treatment can be recycled to the washing vessel 38 .via a line 48. That liquid which is not returned to the digesters 10-16 or the circulation of the rotary feed valve 24 is removed through the line 34 to evaporation, for example (not shown in more detail ). It may also, as in the shown embodiment, be fed into a receptacle 50 where possible residual gases are expelled and removed through a line 52, while tapped liquor from the receptacle 50 is withdrawn for evaporation, for example, through a line 54. It is evident from the above that it is possible by periodically in turn connecting the di sconti nuously operated digesters 10-16 to a detached washing vessel 38 via the rotary feed valve 24 to cause a discontinuous digester house to operate continuously behind the rotary feed valve, the fibre material thereunder pass ng a layer of liquid as is described in the Swedish patent 7408859-2. It is clear that the shown embodiment is an example only of realization of the invention and that the same can be varied within the scope of the appended claims without departing from the inventive idea. Especially shall be emphasized that the used rotary feed device can be formed out in various manners as also is shown and described in the patent application 7609782-3 cited above and that the rotary feed device is provided with required screen means for its function as also is evident from the named application and in the Swedish patents 7316616-7 and 7316617-5.

Claims: CLAIMS 1. Method of transferring materials transportable with a liquid between various treatment stages, preferably from digesting to a subsequent treatment by means of circuits of circulating liquid, c h a r a c t e r i z e d in that material from one or several discontinuous treatment steps are supplied to subsequent continuous treatment steps by the material being fed into the continuous step by displace¬ ment by means of a liquid portion withdrawn from the- said step. 2. Method • accordi ng to claim 1 , c h a r a c t e r i z e d in that the liquid accompanying the material from the dis¬ continuous treatment step is displaced by means of the liquid withdrawn from the continuous step before the material is supplied to the last-mentioned step. 3. Method according to claim 1 or 2, c h a r a c t e r ¬ i z e d in that the material is a fibre material and that the continuous step is constituted by washing ' of the fibre materi al . 4. Method according to any of the claims 1 - 3, c h a r a c t e r i z e d in that the treatment step con¬ sists of a subsequent digesting step, e.g. a sorption digesting step. 5. Method according to any of the claims 1 - 4, c h a r a c t e r i z e d in that the extracted liquid is withdrawn from the discontinuous treatment and that the heat content of the extracted liquid is used for evaporation. 6. ' Method according to any of the claims 1 - 5, c h a r a c t e r i z e d in that the discontinuous treat- ment consists " of digesting of fibre material and that the material is washed in the same treatment step prior to the transfer thereof to the continuous step. " BURETTE __________ ■ ^?NATlO^>' 7. Device for carrying out the method according to any of the preceding claims for transfer of material transport¬ able with a liquid between various treatment steps comprisin circuits of circulating liquid disposed between the treatmen steps, c h a r a c t e r i z e d ' . ' n that the transfer is effected by means of a rotary feed valve (24) to which the circuits of circulating liquid are connected. 8. Device according to claim 7, c h a r a c t e r i z e in that the rotary feed valve (24) is connected to two or more circuits of • ci rcul ating liquid, preferably three " or four. 9. Device accordi ng to claim 7 or 8, c h a r a c-t e r - i z e d in that one circuit of circulating liquid is connected to an accumulator, such as a flash tank (50) or the like for withdrawal of liquid from the discontinuous treatment step.

Inventors: GLOEERSEN S
Applicants: GLOEERSEN STIG, GLOEERSEN S
Application year: 1979
Main classification: D21C7
IPC codes: B01J8, D21C7