FI93747C - The reaction tank - Google Patents

Description

93747

REACTION TANK - REAKTIONSBEHÄLLARE

The present invention relates to a reaction vessel, the upper part of which acts as a reaction part and the lower part as a dilution and / or washing part.

Peroxide bleaching or a delayed reaction has traditionally taken place in a relatively large tank, with the upper part acting as the reaction part and the lower part as the dilution / washing part.

10 Separating these functions from each other, or managing both, has produced problems: vaulting or, on the other hand, dripping of pulp onto the mixer in pieces that are too large, which have even damaged the mixer. In any case, 15 the consistency adjustment has been difficult And due to the discharge task, the mixer has had to be oversized a lot. It has not been possible to use the high dry matter content favorable for the reaction in the reaction section, but in order to ensure discharge, the mass must have already been diluted in the reaction section.

20 These problems have been remedied by making the reaction section a separate silo with unloader and conveyors. The dilution / washing tank is located separately and the mass is transferred to it by a conveyor.

25 However, this solution is expensive and bulky. The conveyor system can also be white to dimension without problems; there are even masses that cannot be transported with a screw conveyor, for example.

30

It is an object of the present invention to take advantage of the advantages of both of the above methods while avoiding the disadvantages.

The reaction part of the container according to the invention is a pulp silo known per se, which is provided with a discharge device movable on the bottom and on the bottom. The bottom of the silo has the necessary number of discharge openings that can be positioned and dimensioned optimally for the plug flow in the silo and around the bottom. This also avoids unnecessary transport of the pulp along the bottom of the silo and at the same time saves energy and wear on the structures. The discharge openings can be equipped with hatches to allow the process to be quickly controlled when the filling of the silo is started.

As an extension of the silo, directly below the discharge bottom, but separated by a suitable air space 10, there is a mixing / washing / dilution section. This solution avoids transporting the pulp from the reaction silo to the mixing tank, but still - the reaction - discharge and 15 - dilution / washing / mixing operations are separately controllable.

The reaction vessel according to the invention is characterized in that the reaction part and the dilution / washing part are separated from each other by a discharger and an intermediate base provided with discharge openings. Most preferably, the discharge openings are shaped so as to prevent vertical discharge and the discharge from the reaction section takes place only when pushed horizontally by the discharge device.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 is a schematic, partially sectioned elevational view of a reaction vessel according to the invention, Figure 2 shows a section of Figure 1 along line AA, Figure 3 shows a section of Figure 1 along line BB, Figure 4 is an axonometric view of Figure 1. and Fig. 5 shows a detail of the midsole of the reaction vessel according to an embodiment.

'* P855 / F4 3 93747

Figures 1-4 show a typical reaction vessel 2 according to the invention. The reaction vessel consists of an upper part 4 and a lower part 6 separated by an intermediate base 8. The intermediate base is provided with a plurality of elongate discharge openings 14 delimited laterally by radial edges 10 and 12. 16 is fitted with an eccentric 18 in which an unloader 22 provided with discharge arms 20 is mounted. The hem of the top wall of the container has claws 24 and the ends of the discharge arms have rollers 26, 10 which together control the movement of the unloader so that it slowly rotates along the surface of the midsole as described in Finnish patent application 881926.

The top of the tank has a pulp feed port 28. 15 The bottom of the tank has a pulp outlet 30. It also has a feed port 32 for dilution / washing liquid. A stirrer 36 and a service space 38 for the unloader drive 40 are arranged in the lower part of the tank.

20 The hinges 42 are hinged to the radial edges 10 and 12 of the discharge openings 14 of the midsole, by means of which the discharge openings can be partially or completely closed.

In the embodiment shown in Fig. 5, an obliquely downwardly directed plate 44 is attached to an edge 10 upstream of the discharge arm 20 of the discharge arm 20 in the midsole 8 25. The plate forms a substantially vertical opening 46 with the downstream edge 12 of the discharge opening. from it vertically and the unloading takes place: only horizontally pushed by the unloader.

The disk can be either permanently mounted or alternatively G \ P0855 \ P855.EN.

4 95747 pivotally hinged so that its direction and thus also the size of the opening 46 is adjustable.

The pulp is fed to the reaction tank, e.g. for peroxide bleaching 5, in a dry matter content of about 30%, in which case the necessary chemicals have been mixed into the pulp beforehand. At the bottom of the tank, the pulp is washed and diluted to a consistency of about 3 to 6%.

The invention has been described above with reference to the preferred application examples shown in the figures, but it will be clear to a person skilled in the art that the invention can be modified in many ways within the scope of the inventive idea defined by the appended claims.

15

II

P855 / F4

Claims (5)

A reaction vessel (2), the upper part of which acts as the reaction part and the lower part as the dilution and / or washing part, the reaction part (4) and the dilution / washing part (6) being separated from each other by means of a dispenser (22) and dispensing apertures (14) provided with the intermediate bottom (8), characterized in that the dispensing apertures (14) are formed such that they prevent the dispensing vertically and the dispensing from the reaction part (4) occurs only horizontally by displacement performed by the dispenser (22). Reaction vessel according to claim 1, characterized in that at the substantially radial edge (10) which is upstream relative to the direction of movement of the discharge opening (14) of the discharge opening (14), an obliquely downwardly directed plane ( 44) which together with the edge (12) which lies downstream of the discharge opening forms a substantially vertical opening (46). Reaction vessel according to claim 2, characterized in that the direction of the plate (44) and thus also the size of the opening (46) are adjustable. Reaction vessel according to claim 1, characterized in that the discharge openings (14) are provided with a closable door (42). 30 5. Reactor container according to claim 4, characterized in that the hatches (42) consist of a plate (44) which is rotatable with threaded hooks attached to the edge of the discharge openings (10, 12).