US2901149A - Device for feeding comminuted cellulosic fibrous material into a pressure vessel - Google Patents

Description

Aug. 25, 1959 o. .1. RICHTER 2,901,149 DEVICE FOR FEEDING COMMINUTED CELLULOSIC FIBROUS MA Filed March 7. 1958 TERIAL INTO A PRESSURE VESSEL 2 Sheets-Shea; 1

Aug. 25, 1959. RICH-[ER 2,901,149

DEVICE FOR FEEDING COMMINUTED CELLULOSIC F IBROUS MATERIAL INTO A PRESSURE VESSEL Filed March 7, 1958 v 2 Sheets-Sheet 2 //v VE/VTOH' 045 Jo/071v Fla/HER DEVICE FOR FEEDING 'COMMINUTED CELLU- LOSICFIBROUS' MATERIAL INTO A PRESSURE VESSEL Ole Johan Richter, Fa'cture, France, assignor to Aktiebolaget Kamyr, Karlstad, Sweden, a company of Sweden Application March 7,1958, Serial No. 719,912

S'CIaims. '(Cl. 222-367) The present invention relates to a device for feeding cornminuted cellulosic fibrousmaterial, e.g. wood chips,

straw, etc., into a pressure vessel by using a charging valve device comprising a rotor having one or more diametrically arranged, charging passageways, which rotor isrotatably mounted in ahousinghaving at its upper side an'inlet port, through which a charge of the material can be introduced intothe passageways of the rotor, and said housing having'on the lower part of'o'ne side an outletfport through which the charge can be delivered to the pressure vessel.

The object of the invention is to provide avalve device of the character mentioned, such that the content of the charging passageways can be flushed out by meansof a liquid at approximately the same pressure as, or slightly higher than, the pressure prevailing in thezpressure vessel, and such that the said flushing can take place without the liquid used therefor being transferred to the lowpressure side of-the charging valve. This means that the charging passageway should be emptied of its entire content of cellulosic fiber material as well as the flushing liquid, during the time period when it is in communication with the outlet port. Instead, according to the invention, said'passageways'will'be filled with gas, usually stearn, from'the pressure vessel,=after theflushing iscompleted.

An essential characteristic of'the inventionlies in the provision of a valve housing having outlet port disposed on one side thereof and, opposite'to said outlet port, a flushing liquid supply port which, in its entirety, is

located abovethe-horizontalplane through the axis of a rotor mounted in the housing. In addition, the crosssectional area of the supply port covers a center angle considerably less than the center angle of the outlet port and is located diametrically opposite to a portion of only the lower half of the outlet port. Further, the outlet port is connected to the pressure vessel by means of an inclined conduit. As will be explained hereinafter, this permits a gravity feed of the flushing liquid into the pressure vessel after the flushing operation.

The application of the invention to a continuous cellulose digester will be more closely described hereinbelow with reference to the accompanying drawings.

Figure 1 shows diagrammatically a cellulose digester pressure vessel provided with a charging valve device according to the invention for introduction of the cellulose fiber material; and

Figures 2 to 5, respectively, show the charging valve device in detail on an enlarged scale and in different positions during operation.

Referring to Figure 1, there is illustrated a cylindrical cellulose digester pressure chamber 11 having a supply conduit 25 arranged at the upper end thereof. A charging valve device 17 is arranged on supply conduit 25. Hopper 13, provided with partition 47, supplies a mixture of fibrous material, such as wood chips, straw, etc., and digesting liquor, delivered by means not shown, to charging valve device 17. Steam line 43 is arranged to deliver United States Patent posite'inlet port 27. The-angle V indicates the arrangeexcess steamfrom charging valvedevice =17 to hopper 13,

'side of sieve 33 and digester liquid is-drawn therethrough 'by pu'tnp 31 arid circulated by line 34 controlled by valve 34A into heating device 35 and'thence through line 29 into charging valvedevice '17. Steam is-supplied to the heating coils through steam line 39 at a ratecontrolled by control device'37 tomaintain the desired temperature of the digester-liquid in line 29. Thedigested fiber material will be continuously withdrawn at the bottom of digester 1-1 at a rate such that the digester is always incompletely filled, its upper'end containing'only steam.

Referring to Figures 2, 3, 4, and 5, charging valve device 17 is seen to comprise a housing 16 provided with a feed inlet port 21, a feed outlet port 23, a digester liquid supplyport 27, and a steam release port 41. 'R0- tatably mountedin housing 16 is a rotor 19 which-is rotated clockwise as indicated by-any suitable means, not shown. Rotor 19 is-providcd with at least one charging passageway 26 extendingtransversely through the rotor. When rotor 19'is rotating, the passageways 26 will alternately be "in-communication with ports 21, 23, 27, and 41, as can be seen from the respective positions shown in Figures 2, 3, 4, and 5. Steam release port 41 serves only to equalize 'theip'ressures acting on the rotor. Any steam released therethrough will be carried to hopper 13 by steam line 43 where it serves -to heat the charge therein.

Referringto-Figures 2 and 4, center'angle V -indicates the angle subtended by the cross-sectional area of liquid supply port 27, and center angle V indicates the angle subtended by the-cross-sectional area'of outlet port 23. Points 01 and b definethe portion of the cross-sectional area of the outlet -"port 23 "which is diametrically 0p- Inent of-liquid irilebport 2.7 above the "ho'rizontalrplane, indicated by line C, drawn through the "axis of rotation of rotor 19.

According to the invention, the supply port 27 is situated in its entirety above the horizontal plane C passing through the axis of the rotor, and angle V (measured from the center of the rotor) is small in comparison to angle V Furthermore, while supply port 27 is situated in its entirety diametrically opposite to outlet port 23, the midpoints of said ports are not located on the same diameter but are somewhat displaced towards the inlet port 21. Thus, the diametrical projection of supply port 27 lies within the lower half of outlet port 23, as shown, at a, b in Figure 2. Preferably, supply port 27 covers a center angle V (Fig. 4) of about 2 to 5 degrees and forms, with the horizontal plane C, an angle V of about 25 to 35 degrees. Outlet port 23 covers a center angle V of 35 to 42. degrees and is preferably located completely below the horizontal plane C (see Figure 2) through the axis of rotor 19, although a small part thereof may be located above said plane. The orifices of passageways 26 preferably cover approximatel the same center angle as outlet port 23 or a slightly smaller angle, of for instance about 30 to 40 degrees. Inlet port 21 is approximately as wide as outlet port 23 and may be somewhat displaced from the vertical plane of the rotor axis in the direction towards outlet port 23.

In operation, fibrous material from hopper 13 will be delivered through supply inlet port 21 into charging passageway 26 when the latter is in a substantially vertical position, seen in Figure 2. l

On rotation, the passageways will be initially wholly shut off, containing the charge under atmospheric or a low overpressure, and will thereafter reach the position shown in Figure 3, that is, partly opening into communication with outlet port 23 but not yet in communication with liquid supply port 27. At this point, steam from digester 11 will flow into passageways 26 and the pressure therein rises to the digester pressure. Further rotation will provide communication between liquid supply port 27 and outlet port 23 through passageway 26 in the position shown in Figure 4. At this stage, the heated digester liquid from line 29 will enter through supply port 27 under the pressure developed by pump 31 and will flush the charge in passageway 26 through outlet port 23 and conduit 25 into digester 11, as at Figure 4.

As shown, the lower or left-hand end of passageway 26 forms with outlet port 23 an opening which still is quite wide when the flushing period ends. When rotor 19 reaches the position shown in Figure 5, supply port 27 is closed and the remaining content of passageways 26, which as a rule consists merely of flushing liquid, flows out by gravity. The lower side of passageway 26 slopes towards the outlet port 23 in this position, and is situated at a level above the bottom of the port. Thus, this stage does not prevent a complete emptying. As passageway 26 is emptied of liquid, it is filled with steam coming from digester 11, at the digester pressure. The steam meets the liquid flow in countercurrent in conduit 25, but as this passage slopes and is quite wide, the two currents do not interfere with each other. When the rotor is turned from the position shown in Figure 5, the passage 26 is completely shut off and is then opened against the inlet port 21. The steam of the pocket, expanding to the pressure of the inlet, is led ofi through the space stormed by the partition 47 at one side of the inlet port 21 and adjoining hopper 13. Rotor 19 will finally complete the cycle on reaching the position shown in Figure 2, and the above-described course can be repeated.

From the above description, it will be seen that the invention provides a charging valve device which permits flushing of the charge in the valve into the digester by means of circulating heater digester liquid, but avoids any possibility of such liquid being transferred to the low pressure, i.e., hopper, side of the valve. The design also permits the maximum quantity of material, as determined by the size of the passageway in the rotor, to be delivered with each revolution thereof.

While the above description has related primarily to a rotor having one passageway, it will be apparent that several passageways can be provided. In such instances, it is desirable to have the passageways angularly disposed to each other and axially displaced along the rotor. As will be apparent, in such cases some of the ports will be duplicated to insure proper operation.

Accordingly, it will be understood that this invention is not limited to the specific embodiments hereinabove described and illustrated but only by the spirit and scope thereof as defined by the following claims.

I claim:

1. A charging valve device for feeding fibrous material or the like into a pressure vessel comprising: a housing having spaced feed inlet and outlet ports; a rotor body rotatably mounted in said housing and having at least one passageway extending transversely therethrough; means for rotating said rotor body about a horizontal axis for sequentially placing said passageway in communication with spaced inlet and outlet ports; said passageway extending through said rotor transversely to said axis; said housing having a liquid supply port arranged for communication said outlet port through said passageway, said feed inlet port and said liquid supply port being entirely disposed substantial-1y above the horizontal plane through the axis of said rotor body so as to be out of communication with said passageway when said passageway is in the horizontal position, said inlet port being located on the periphery of said housing and so as to be in communication with said passageway at least a portion of the time when said passageway is in communication with said outlet port; wherein the center angle from the axis of said rotor subtended by the cross-sectional area of said liquid supply port is substantially less than the center angle subtended by the cross-sectional area of said outlet port.

2. The charging valve device of claim 1, wherein said liquid supply port is arranged diametrically opposite the lower half of said outlet port.

3. The charging valve device of claim 1 wherein said liquid supply port is arranged sufiiciently above said horizontal plane so that at least part of the time that said passageway is out of communication therewith, said passageway will incline towards said outlet port.

Hagen Mar. 21, 1939 Kronstad July 7, 1953

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