US2283155A - Apparatus for regulating and delivering paper stock to papermaking machines - Google Patents

Description

May 12, 1942. R. 'r. LANG 2,283,155

APPARATUS REGULATING AND DELIVERING PAPER STOCK TO PAPER MAKING MACHINES Filed Dec. 15, 1938 RRMRRB Patented May 12, 1942 UNITED STATES f PATENT OFFICE t 2,283,155

APPARATUS FOR BEGULATING AND nnuv- ERING PAPER STOC MACHINES K TO PAPERMAKING Richard T. Lang, Heidenheim on the Brenz, Germany, assignor to J. M. Voith, Heidenheim on the Brenz, Germany, a eopartnership composed of Walther Voith,.Herman' Voith, and Harms Application December 15, 1938, Serial No. 245,965

. In Germany December 16, 1937 2 Claims. (CI. 92-4 This invention relates to means for supplying paper pulp to the wire of paper-making machines. The invention also relates to closed pipeline stocksupplies, using a stock pressure box.

like that shown in my prior application for Letters Patent of the United States, filed under Serial No. 179,881 on December 15, 1937.

In such closed pipe lines, contrary to the ar-.

rangements with open stockinlets, the stock has no opportunity to de-aerate.. In the open stock inlets the pressure is regulated by increasing the hydrostatic head. This cannot be done means of aseparate quick-closing slide valve g1..

with a closed stock pressure box. It is the object" 1 of this invention to solve this problem. It is especially necessary to maintain the outlet pressure constant; and avoid great changes in the stock consistency after it has once been regulated. It is alsodesirable that during the whole production the jet of the pulp discharged from the nozzle of the closed stock pressure box always has the same direction and meets the wire of the paper-making machine at the same place. Uniformity is also desirable since every change in the once-fixed conditions must lead totrouble and loss-in the production. It is, therefore, of

' fundamental importance in the use of closed stock pressure boxes, that the fixed working conditions are maintained during the whole production process.

A further object of the invention is to provide a circuit for the flow of the stock in the event that anything happens to the paper-making machine and it is necessary to cut off the nozzle supply to the wire, this circuit enabling the stock to be continually passed therethrough under maintenance of substantially the same density so as to be ready to be supplied by the nozzle to the wire upon opening the valve supplying the stock to the nozzle, and so that the stock is then in substantially the same condition as it was prior, to the interruption.

The invention also contemplates the combination of parts and their novel cooperation so as to endeavor to obtain irreproachable and pericctly uniform paper texture.

embodiment illustrated, strainers are indicated is also introduced the pulp, adjusted to the correct quantity in'the usual manner by means of pulp-regulating slide valves or quantity regulators, by a separate pulp pipe 9. The pulp supply through the inlet pipe g is usually regulated by a regulating member of known construction,

for instance a regulating slide valve 92, butin case of need the inlet pipe maybe shut off by The pump p mixes the pulp and the white water .and delivers the mixture to the usual pulp clean- 1 ing appliances d,. for instance strainers or the like. The delivery pipe p2, leading to these cleaning appliances 11 may of course be branched and sub-divided according to the number of such appliances-while regulating members d1 provided therein distribute the desired quantity of pulp.

to the individual cleaning appliances d. In the as the cleaning devices. It is obvious that any cleaning appliance of known kind can be employed at this place.

The strainer or strainders d'pour their con tents into a largecollecting box e. The latterserves both for the satisfactory dc-aerating of the pulp'thatis ready for the machine and also for the accommodation of a supply of pulp, so as to compensate in this way for'minor fluctuations in the pulp. On the storage tank e there may be provided an adjustable overflow ez. The excess pulp is thenconveyed by a pipe e; to the white water-collecting tank S. This overflow e: only comes into operation when a float er, and regulating members influenced thereby, are not switched on or are disturbed. From the deaerating and storage vessel e the pulp flows to an adjustably driven pump a. which feeds the stock inlet B. From the outlet of the reservoir e, onthe way through the suction pipe ar, the

pump a and the delivery pipeaz, tothe pulp outi let point C between the lips, the pulp is guided One embodiment of the invention is illustrated by way of example in the accompanying-drawing which is a diagrammatic elevation view.

Underneath the wire part of the paper-makin machine the white water collects in a'reservoir S, I

provided for the purpose. From therethe white water runs in a connecting pipe .91, which can be closed by means of a regulating member s:, with a suitable gradient, to the suction side in, of a pump p. Into the suction pipe p1 of this pump p -of the mixing pump p must be controlled by a regulating device of known kind, which automatically regulates the speed of revolution of tank e.

this pump 11,. by means of a float er, in dependence upon the level of the pulp in the storage When pump drives capableof being regulated are employed, the pulp-feeding and regulating system works in the following manner: With an unchanged lip aperture at the outflow spout C of the stock inlet B, and with constant dilution and constant specific gravity of the pulp ready for the machine, the pressure necessary in the stock inlet can be adjusted either in dependence upon the speed of the paper machine or inde- I of revolution and therefore a definite output of the pressure pump a. fitted into the storage reservoir e and consisting of a float e1 is for the purpose of keeping the pulp level in the strainers d and therefore the suction height of the pressure pump a .to the same level by regulating the mixing pump p in order that the operating conditions for the pressure pump a may always remain unchanged. For the satisfactory working of the stock inlet B, it is absolutely essential that the speed of the pressure pump a, when once adjusted, should be kept quite constant. On this ground, even in connection with circuits that are found by experience to exhibit no great fluctuations of voltage or of frequency, the motor as of the'press'ure pump a is equipped with an electrical quick-acting regulator for instance, which keeps the speed, when .once adjusted, absolutely constant.

If the pressure pump aand the mixing pump p are not driven'by motors that can be regulated, the by-pass pipes 114, p4, shown in dot-and-dash lines in the figure, must be provided, for the purpose of regulating the output of the pumps. The pumps work in this case at their full power, while the excess quantity of stock not needed on the machine is'returned by' the by-pass pipes d4, m from the pressure pipes (12, m to the suction pipes a1, 91. The adjusting of the requisite. pressure in the stock inlet B is effected withthis arrangement either in dependence upon the speed of the paper machine or independently thereof by regulating a by-pass slide valve associated with the pressure pump a. The maintenance of the level in the storage tank e is effected by means of a float e1, which acts upon a throttle valve 2 5 in the by-pass pipe 124 of the mixing pump p.

If the mixing and pressure pumps a and p are constructed as propeller pumps, it is also possible, by shifting the blades of the rotors when stationary, to adapt the output of the pumps to the production of the machine, so that the quantity of stock flowing back through the by-pass a4 and 124 for instance can be kept fairly small.

In order to enable the supply of pulp to the stock inlet B through the pressure pipe a: to be interrupted, which is very important at high working speeds, there is provided in the delivery pipe a: a special shut-off member I, such as a rotary valve. By adjusting this valve f the delivery pipe a2 is directly connected by way of an emptying pipe f1 with the collecting tank S for the white water. The pulp therefore no longer rises in the stock inlet B, but is circulated within the system. Simultaneously with the actuation of the rotary valve f in the pressure pipe as, the quick-closing slide valve g1 in the pulp inlet pipe g is closed, in order that the pulp ready for the machine and circulating in the system may not be enriched by further pulp. For the approximate maintenance of the conditions once adjusted in the pulp-feeding and regulating system,

The regulating device ,"loaded' check valve f2.-

Provisio'n is made for all the regulating. mombers of the pulp-feeding and regulating system. for instance g1. 92. d1, 175,05, 1 and s2, to be. readily accessible, and to'be capable of being controlled I ina simple manner from the paper machine floor. i

By the stock inlet accordingto my application Serial No. 179,881, in conjunctionwith the pulpfeeding and regulating system accordingto my invention aforementioned, a paper of satisfactory and completely uniform texture is ensured even with high speed paper-making machines.-

'It is obvious that'various changes and modifications may be made in the details of construction and design of the above specifically described embodiments of this invention without departing from the spirit thereof, such changes and modifications being restricted'only by the scope-of the following claims.

head box, the combination with said head boxpipe of a closed circuitfor the flow of the stock when the stock to the pressure head box is interrupted', said closed circuit consisting of a white water tankbelow the wire, a mixing pump, a valved stock inlet pipe for said mixingpump, a pipe extending. to said mixing pump from the white water tank for guiding the contents of,- said tank to the mixing pump, a stock storage tank, a pipe extending from the mixing pump to the stock storage tank, a pressure pump for receiving stock from the storage tank and pumping the same through the head box pipe, a pipe connecting the storage tank and pressure pump, a stock supply cut off valve connected with said head box pipe, and a pipe connecting said white water tank with said stock supply cutoff valve, whereby upon the closure of the valved stock inlet pipe and the stock supply cutoff valve, the continued operation'of the mixing and pressure pumps continues the flow of stock in said closed circuit without enriching the stock by a further supply of stock, to enable the supply of stock which will be fed upon the wire upon resumption of operation to be of substantially the same density, quantity and pressure of the stock at the wire, as existed prior to the interruptionwhich took place when said valved stock inlet pipe and said stock supply cutoff valve were closed.

2. In an apparatus for regulating and delivering paper stock to Fourdrinier paper-making machines having a wire, a stock pressure head box with a stock flow nozzle for supplying stock to the wire, and a stock supply pipe having one end thereof connected with thestock pressure head box, the combination with saidheadbox of a closed circuit for the flow of the stock when the stock to the pressure head'box is interrupted, saidclosed circuit consisting of a white 'water tank below the wire, a mixing pump, a 'valved stock inlet pipe for said mixing pump, a pipe extending to said mixing pump from't-he white water tank for guiding the contents of saidtank to the mixing pump, a stock storage tank, a pipe QAQSJBB stock supp y cutofl valve, the continued operation of the and pressurepumps continues the flow of stock in said closed circuit without.:' en-'- riching the stock by a further supply of stock,

to enable the supply of stock which will be fedupon the wire upon resumption of operationto be of substantially the same density, quantity and pressure of the stock at the wire js existedprior to the interruption which took place' when said valved stock inlet pipe and saidstock cutoff valve were closed, a valved by-pass connection between the pipes leading to and iromjshe. mixing pump, a valved by-p'ass connection Joetween the pipes-leading to and from the pressure pump,

whereby said closed circuit passes through the by-pass connection.

RICHARD T. LANG.

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