Feeder for solid materials

Oct. 17, 1967 G. τ. HUTCHISON 3,347,741

FEEDER FOR SOLID MATERIALS

Filed Jan. 13, 1964

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INVENTOR.

GIBSON T HUTCHISON

BY

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3,347,741

Patented Oct. 17, 1967

United States Patent Office

3,347,741

Cihsnn T^Fn^EPi ^{R F}?^{R S0LID} MATERIALS ^G,bS° J’ ^Η^^0Π’™ ^{apk Glen}’ ^Pa&gt; ^assignor ‘θ Crane ^C iriFa i ⁸°’» corporation of Illinois Filed Jan. 13, 1964, Ser. No. 337,458

Claims. (Cl. 162—241) abstract of the disclosure

An apparatus for feeding wood chips to a pulp digester compnsmg a transfer chamber and means for eguaS the pressure m the transfer chamber and the digested S tran_sfel^S°h?^r°h^Vlde_f^{d means for ap}P^I5'ⁱⁿS a vacuum to . e transfer chamber for removing the air from within the intricacies and . between the fibers of the wood chips while contained within the transfer chamber.

_t, J^{he sing!e} fi^gure °f ‘he drawing illustrates the invenIt wiil^She^PP ? t ^&amp;εκ^{6Γ f}°^{r a continuous} Pulp digester, nil ?hu ft rf ^{the inVenti}°^{n is more} generally usechip and the ^ma‘^{enal handIed need not be} wood »“·“Χ£Λ »^f ”°^d * There is indicated at 2 a continuous digester, which mav igester 2 is maintained at an elevated cookin tempera necfion 4^Pin^eth^Ue^rt ^C0”^dition; ^{Digester 2} has an°inlet connection 4 in the top thereof. Mounted above the digester 2 m alignment with the inlet connection 4 is a bin «i con di iestertdWif Ά ^{Μ t0 be fed to the}_aester and having an open bottom end. In vertical alin ment between the open bottom end of the ffin 6 and fhe conduitiⁿn^Ctl°H^{n 4} Γ® ^{an Upper COnduit 8}&gt; ^an intermediate conduit 10 and a lower conduit 12, these conduits coupled together at suitable flanged The upper cond ? therefrom'iniihf ^b°^ttOm °^{f the bin 6 for} reiving flow inlet f f^d f ^{10Wer COnduit 12 is} connected to the S ⁴ «»» «ί »iid fnto tte uigvolCl .

flow ^{is provided} in conduit 8 for controllin the flow of solid material therethrough. Valve 8 mav be nf

S’ .- ^uPPsr

XX^s S,“T A⁸ “B .-K'S £ Sg* - upper enTofti^digester ^{34 and} f^he

Soug? ^C°^{nneCted in line 36} controlling^owtoerT the transfer chambeTofgfes and^quid^f⁰ B^aCUatethere is provided a jnihsi ^lci^u,d· To this end, connected to the transfer ch ^S0lIrce ^² which is and 34. A valve 46nifn T ^{by Way of Iines} 36 the evacuating means”! ^°^{18 the COMection to}add the cooking”liquoΓίο ^η'ίΛ· ^{desirable to}chamber. Accordin1v m_A5, ^{d cblps ln} the transfer cooking liquor at thL f f^{8 a}f^{e pro}y^ided for introducing and the upper portion of the transf n ^C0°^{king h}quor 50

3“ “ “ «-X“« 3SS ^Λ be deSlbedT °' »? bow

A^foX· »' “«3 ·™·' «nd _M. _{b tte 0}^!’7t_hS“” “

This invention relates generally to feeders for solid materials of the free flowing type.

such mntlr^e ,ⁱⁿ?^{ntion is} applicable broadly to feeding of such materials from a supply thereof to a vessel in which the pressure is greater than the pressure of the supply it to the f ^{eSC! lb}!i^{i bereafter as} h ^is applicable specifically 25 P.1P diX °' ’“&lt; * &gt;» * . In the paper industry, pulp digesters in the past have ffl?· Τΐ.^ΡΓ°““ ” ·^,ΛύΛ ·- «ΛΠ1·® «ηίιΐϊ b-tth b 3°? ^a “°^ki”^{2 30} end nt th ^{h S}.^{heated at a} cooking temperature. At the doln t ^Η w ^Ok”^g ?^yCle’ ^{the chips and} iiauor are blown down to a blow tank where steam flashes to atmosphere or other points in the process, and the digester is emptied m preparation for another charge. Obviously a contif ³⁵taXZTto °L^pt^uh^{p digestion would have} -W reason of the r · ^PF0CeSS’ ^{SUch as greater} output by reason of the elimination of the heat up and blow down ^{by reason Of beiter process} conOne of foe mn^daPiabu ^lty °^{f the pr0Cess to} automation. One ot the mam problems encountered in the provision of a satisfactory continuous digestion operation is the metering and feeding of the chips into the digester whkh s at an elevated pressure and temperature. Prior feedine devices for such an operation have involved the use of a ^Por exa JA7draiT«cTA^VΓo:«),'^,v«lves^e«L·e^Sdiat solid matenai from the supply to the transfer chamber and a control valve for controlling flow from the tramfer chamber to the digester. The control valve” also e“ L —

·. rny be «33333^ pctaeyed by the pro.ieta of « _c„_Jr ’ /“ V_t chamt^oHock.⁰⁰¹¹^^{11011011 Λβ SiZe} °^{f the transfc}r ' . The foregoing and other objects and features nf th» lowing de“eS. °' SZ '

3,347,741 chamber is sealed at both ends. The next step is to relieve the pressure in the transfer chamber, which pressure is at the elevated pressure of the digester. In this step all the valves are closed with the exception ot the pressure relief or vent valve 40. This valve 40 is left open a time sufficient to permit the pressure m the transfer chamber to drop to approximately atmospheric pressure.

The next step is to open the valve 14 in preparation for the feed of chips into the transfer chamber. This opening is effected by operation of the valve actuating means ¹⁰ 18 which moves a valve member to open the passage through conduit 8. During this opening movement of the valve member, vent valve 40 and control valve 30 are the only valves which are open. The open condition ot 15 control valve 30 permits the flow of high pressure Mum or steam from source 26 to the nozzles 22 whereby jets of fluid are directed to clear the valve gate and seat.

The apparatus is now in condition for another tilling of the transfer chamber as discussed above. Accordingly, another charge of wood chips contained in the bin 6 will fall into the transfer chamber by gravity flow to fill tne space between the same.

The above description of the operation covers one cycle, and it will be apparent that this cycle may be re25 peated to provide a continuous feed of chips to the digester at a desired rate. Preferably, the cycle may be time controlled with each step taking place a specified time interval and the cycle being repeated at regulated intervals thereby metering the feed rate. However, certain 30 steps could be terminated in accordance with other measurements, such as, pressure, temperature or level.

It will be apparent that various of the above steps may be omitted when not required for a specific process. Moreover the cycle, steps and arrangements described above 35 may’vary from one installation to another, depending on the raw stock, the end product and the overall P^roccsj·

A modification of the above cycle which will tend to prevent chips from bridging or archmg m the bin would involve opening the valve 14 just before the pressure in 40 the transfer chamber has reached atmospheric in its decay during the pressure relief step. This will cause a small puff or surge of gas from the transfer chamber into the bin through the valve 14 to impose a slight shock or bump to the chips in the bin. This will minimize the possibility of the chips bridging in the bin.

In a modification of the apparatus, the pressure relief valve 34 may be connected to any place where heat may be used at atmospheric pressure, as for example, to perform some type of preheating. This would make use of the high temperature of the gases in the transfer chamber after the pressure equalization step.

It will be apparent that the apparatus in accordance with the invention has several advantageous features, for example, by pressure relieving the transfer chamber before 55 connection to the bin, the apparatus avoids an expl°^sl°n into the hopper. Also, by evacuating the transfer chamber through the valve 48, the air is removed from the chips very effectively since the evacuation is performed on a relatively small space. Prior pulp digestion apparatus have not used the evacuation step because of the large evacua ing equipment requirements and the structural design problems involved in the evacuation of large vessels.

It is to be understood that various changes may be made in the details of the embodiment of the inventive concepts herein contained without departing from the scope of the invention. For example, while the pressure equa izat on in the described embodiment is achieved by connectini t digester so that it serves as a source of pressure equaling vapor, this vapor source could be a separate source at 70 same pressure as the digester. Accordingly, it is not desired to be limited except as required by the following claims.