US3464637A - Laboratory apparatus for determining the industrial beating behaviour of cellulose or paper pulp - Google Patents

Description

Sept. 2, 1969 H. w. SIEWERT 3,464,637

LABORATORY APPARATUS FOR DETERMINING THE INDUSTRIAL BEATING BEHAVIOUR OF CELLULOSE OR PAPER PULP Filed July 1., 1965 INVENTOR HANS WOLFGANG SIEWERT ATTORNEYS 3,464,637 LABORATORY APPARATUS FSR DETERMINENG THE INDUSTRIAL BEATING BEHAVIUUR 01F CELLULOSE R PAPER PULP Hans Wolfgang Siewert, Amorbaeh, lower Franconia,

Germany, assignor to Escher Wyss G.m.b.H., Ravensburg, Germany, a corporation of Germany Filed July 1, 1965, Ser. No. 468,791 Claims priority, application Germany, July 3, 1%4, E 27,333 Int. Cl. 1302c 13/26, 23/02;G01f /14 US. Cl. 241-37 6 Claims ABSTRACT OF THE DISCLOSURE Laboratory apparatus for determining beating behav ior of cellulose or paper pulp. The apparatus includes a refiner driven by an electric motor and having a rotary element equipped with a pumping device, a circulation vessel, a pulp disintegrator having a bottom discharge opening into the vessel, and flow connections leading from the bottom of the vessel to the refiner inlet, and from the refiner outlet to a conical distributor in the top of the vessel. The width of the beating gap of the refiner is adjusted manually or automatically; the automatic control including a servomotor connected with the gap-adjusting device through a clutch and serving to maintain constant the power consumed by the drive motor. As the clutch is coupled and uncoupled, respectively, a net consumption meter in the power supply circuit of the drive motor is automatically switched on and off.

An exact knowledge of the grinding or beating behavior of cellulose or paper pulp in the factory is of importance for examining the suitability of freshly submitted samples with, at first, unknown paper-technological properties, and also for the optimum adjustment of the beating machines existin in the factory, and for many other purposes. Consequently, also, attempts have been made in different ways to determine this property of cellulose and paper pulps in the laboratory as accurately as possible in the shortest possible time. In the development of the known methods, the principal stress has been laid either on approaching practice as closely as possible, or while refraining from this more or less, on the highest possible reproducibility of the results and maximum classification sharpness.

In the course of development of these methods, it has been found that test beating of the cellulose pulp or paper pulp in a small laboratory refiner, preferably i a conical refiner, is in many respects preferable to other methods, provided one proceeds in a definite manner. The use of a refiner affords the advantage that this machine has the same susceptible criteria as the usual beating machines used in industry. It is essential, however, that the true beating energy consumed during the test beating is suitably determined, and the variation in the physical properties of the investigated pulp during the beating process is plotted against that consumption. By determining the true beating work, that is to say, a quantity freed from all the losses occurring in the apparatus, for example friction losses in the bearings and stufiing boxes, a quantity is obtained which can be transferred with great accuracy from the laboratory test to the indus trial conditions. Experiments have shown that this is even the case where a refiner is not used in the factory, but some other beating machine is used.

The present invention now relates to a laboratory apparatus, by means of which the process described above can be carried out in a particularly practical and rapid 3,464,637 Patented Sept. 2, 1969 form. The laboratory apparatus according to the invention for determining the industrial beating behavior of cellulose or paper pulp comprises a small refiner, a driving motor therefor, a circulating vessel and a discharge pipe openin into the latter for the pulp suspension to be examined. The apparatus is characterised in that the refiner is combined with an adjusting device for the beating gap width, which for coarse adjustment has a hand-wheel, and for fine adjustment and/or control has a servomotor which is controlled through control devices, known per se, in dependence on the electric power absorbed. Between the rotor adjusting device of the refiner and the servomotor is a clutch, which can be coupled and uncoupled by means of a shift lever, and which in addition has an electric switch, operated by the same shift lever, and which on coupling or uncoupling, switches on or off the driving motor and a Work meter arranged in the circult of said motor.

The new apparatus can be constructed in a particularly simple manner if the clutch is a friction clutch. The said work meter is advantageously constructed as a net consumption meter, that is to say, a meter permitting electrical or mechanical compensation of the idling work.

To achieve better circulation of the fibre pulp suspension, it is proposed to provide at least one conveyor element on the rotor shaft. This conveyor element may be arranged either at the end of the rotor, at which the examined suspension enters the refiner or at the opposite end.

So that the suspension leaving the refiner and returned to the refiner inlet again by means of a pulp discharge pipe does not enter the refiner inlet again without being duly mixed with the remaining suspension, it is proposed to arrange below the outlet of the pulp discharge pipe a preferably conical pulp distributor. To facilitate the work, there may be provided above the said circulation vessel a pulp disintegrator, serving to prepare the weighed cellulose sample which is to be examined.

In explanation of the apparatus according to the invention in more detail, reference is made to the accompanying drawing, which shows the apparatus diagrammatically.

Mounted on a stable assembly frame 1 is a refiner 2, in the example shown a conical refiner, which is connected through an equalising clutch 3 to a driving motor 4. The conical refiner 2 comprises in known manner a stationary hollow cone 5, provided internally with longitudinal knives 6, and another cone 7, arranged inside said hollow cone and carrying on its periphery knives 8, which are also arranged in the longitudinal direction of the cone.

The cone 7 is mounted for rotation about its axis on a shaft 9 driven by the electric motor 4 through the equalising clutch 3. To obtain better circulation of the investigated pulp suspension, there is also mounted on the shaft 9 a pumping device or conveyor element 10, which in the example shown is mounted at the wide end of the rotor cone, but which may also be provided at the opposite end. Finally, it is also possible to provide two pumping devices.

At the pulp inlet end 11 of the refiner 2 is a circulation vessel 12, which has at its bottom a closure 14 adapted to be opened by means of a lever 13.

At the pulp outlet end 15 of the refiner 2 is a pipe 16, which returns the pulp through a bend 17 back to the circulation vessel 12. So that the pulp stream issuing under pressure will not be projected directly into the proportioning device 14, a pulp distributor 19, preferably conical, is provided below the outlet 18.

An adjusting device for the working gap 20, has a hand-wheel 21 by means whereof the rotor can be moved to-and-fro via a shaft 22 in the direction of the double arrow 23. The hand wheel 21 serves for coarse adjustment. The exact gap width can be read 011 on a Vernier scale not shown in the drawing. For fine adjustment of the working gap there is provided a servomotor 24, which can be operatively connected with the gap adjusting device by means of a clutch 25. The clutch is operated by means of a lever 26. Combined with the clutch 25 is an electric switch 27, which simultaneously with coupling or uncoupling the servomotor 24 by means of clutch 25 also switches on or off a work meter 28, connected in the circuit of the driving motor 4. A control apparatus 29 controls the servomotor 24 and hence the gap width in dependence on variations of the power absorbed by motor 4 in such a manner that the same electric power is always consumed by the motor 4. Above the circulation vessel 12, there is advantageously also provided a pulp disintegrator 30, the blade wheel 31 of which is driven by an electric motor 33 through an equalising clutch 32. The pulp disintegrator has on its bottom an outlet 35 adapted to be closed by means of a lever 34, and through which the prepared pulp enters the circulation vessel 12.

A test beating carried out by means of the apparatus according to the invention takes the following form:

First of all, a weighed pulp sample, for example 500 g., is charged into the pulp disintegrator with 12,500 cm. of water. The driving motor 33 is switched on and sets the agitator 31 in motion through the equalising clutch 32. At this point, of course, the outlet must be closed, so that the pulp cannot enter the circulation vessel 12.

While the pulp suspension to be examined is in the pulp disintegrator 30, the whole apparatus is filled with water via the circulation vessel 12. The working gap 20 is adjusted approximately to the desired value by means of the hand-wheel 21, and the machine is now started by operating the clutch lever 26. The work meter 28 then measures the idling work now being consumed, which is either noted, or if 28 is a net consumption meter, is compensated by operating the compensation device such that the meter is now stationary.

After this preparatory work, the apparatus is emptied, and the fibre-water suspension, which has in the meantime been prepared is discharged into the circulation vessel 12 from the pulp disintegrator 30 by opening the outlet 35. When the closure 14 has been opened by means of the lever 13, the beating gap 20 is adjusted by means of the hand-wheel 21 so that the apparatus takes approxi-- mately the desired power. This power is dimensioned such that, under the existing conditions, a technical realizable beating period is obtained. Clutch 25 is now operated by throwing over of lever 26. This operates at the same time switch 27, which now switches on the work meter 28. The control device 29 controls the servomotor 24 in such a manner than an always constant power is recorded in front of the apparatus, so that the same work is always performed on the investigated samples. This work is naturally greater than the idling work registered by the work meter 28 in the preliminary test, since pure water is no longer circulating in the apparatus but a solid-water suspension.

At intervals of a few minutes, better after constant work consumptions, samples are taken repeatedly from the circulation vessel 12, by means of which, possibly after forming a sheet of paper, the desired physical properties are determined in known manner. The weight of the samples taken is also determined as well as the amount of solid matter contained in them, so that the quantity of solid matter still circulating in the apparatus is always known.

The laboratory apparatus according to the invention is distinguished for its working reliability and simplicity of attention. It enables a complete examnation of beating behaviour to be carried out in about 30 minutes.

What is claimed is:

1. A laboratory apparatus for determining the beating behavior of cellulose or paper pulp, comprising in com bination a refiner having an inlet and an outlet for the material to be treated, and a stationary and a rotary member leaving a beating gap between one another; an electric motor arranged to drive said rotary member; a circulation vessel having a bottom discharge connection opening into the inlet of said refiner; a discharge pipe issuing from the outlet of said refiner and opening from above into said circulation vessel; a hand operable device for adjusting the beating gap width; a servomotor for operating said gap width adjusting device; and means for the control of said servomotor so as to vary the beating gap Width in dependence on variations of the electric power absorbed by said electric driving motor to thereby maintain constant the power intake of said motor.

2. The combination defined in claim 1, which comprises a clutch inserted between the gap adjusting device and the servomotor; a work meter arranged in the power supply circuit of the driving motor; an on and 011 switch for said work meter; and a shift lever operatively connected with said clutch and said switch so as to switch on or off said work meter on coupling or uncoupling said clutch.

3. The combination defined in claim 2 in which said work meter is a net consumption meter.

4. The combination defined in claim 1 which comprises at least one conveyor element for the material to be treated, fixed to said rotary member of the refiner.

5. The combination defined in claim 1 in which a conical distributor for the circulating material is provided below the outlet opening of said discharge pipe.

6. The combination defined in claim 1 which comprises a pulp disintegrator arranged above said circulation vessel and having a bottom discharge opening into said circulation vessel.

References Cited UNITED STATES PATENTS Re. 24,185 7/1956 Staege et al 241-37 X 1,988,743 1/1935 MacKenzie 241-247 X 2,371,681 3/ 1945 Durdin.

2,456,249 12/1948 .Bidwell 241-97 2,642,781 6/1953 Croake' et a1 241-37 1,942,920 1/ 1934 Fawkes 73-59 2,615,329 10/1952 Witham 73-63 2,679,757 5/1954 Carpenter 73-59 3,086,905 4/1963 Richardson 73-63 X FRANK T. YOST, Primary Examiner US. Cl. X.R.

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