CH678288A5 - - Google Patents

Description

1

CH678288 A5

2nd

description

The invention relates to plan sifters with a pair of screen frame conductors per plan sifter compartment for receiving screen frames, which form a screen wallpaper when clamped together and rest on the screen frame conductors in a relaxed state without mutual contact with one another.

In the plansifter, the sieve frames are brought to sieve stacks one above the other and clamped in a frame that is suspended freely.

To carry out a wide variety of work, it is necessary to release the tension. Then each sieve frame, regardless of the one above or below it, can be pulled out individually (drawer principle).

in practice, this is basically solved in such a way that each sieve frame is laterally equipped with strips that rest on the guide rails when the sieve stack is unstressed. These guide rails are connected at equal intervals with vertical profiles and form together with these sieve frame conductors. The distance between the guide rails is selected so that there is an air gap between the relaxed sieves, which ensures that each sieve frame can be pulled out individually. The sieve frame ladders are firmly attached to the frame. During the vertical tensioning process, the sieve frames are lifted from bottom to top and pressed together after all air gaps have been overcome. The side strips of the sieve frame are lifted off the guide rails.

When clamping vertically from above, the pair of sieve frame ladders is attached to the frame so that it can be moved vertically. During the tensioning process, the pair of sieve frame ladders is lowered so that the sieve frames are placed one after the other from bottom to top and then pressed together.

The basic disadvantage of both variants is that the maximum number of screen frames that can be stacked is limited. The maximum number depends on the overall height of the sieve frames and the distance between the sieve frames in a relaxed state.

The aim of the invention is to achieve the increase in performance at Piansichtem by making better use of the enclosed space, improving the mass-performance ratio and reducing the specific energy consumption.

It is an object of the invention to increase the maximum number of screen frames which can be brought one above the other while maintaining the drawer principle.

According to the invention, the object is achieved in that the sieve frame conductors are divided into pairs of opposing sieve frame conductor segments, of which one pair is fixed and the rest are vertically movable or all pairs are vertically movable. As a result, when the sieve frames are braced with one another to form a stack of sieves on each pair of sieve frame ladder segments, the characteristic process of touching the sieve frames with one another is initiated in a flowing manner; also in reverse order when the sieve stack is relaxed, the disadvantage of the limitation of the maximum number of sieve frames that can be placed one above the other depending on the height of the individual sieve frames and the distance between the sieve frames, in a relaxed state, is therefore fundamental while maintaining the advantages of the drawer principle eliminated.

The invention will be explained in more detail below using an exemplary embodiment.

Fig. 1 shows a detail of the support structure 4 with sieve frame 8 in the clamped state;

Fig. 2 shows a detail of the support structure 4 with sieve frame 8 in the relaxed state.

Sieve frames 8 located one above the other form a sieve stack. Plansifters can consist of two, four, six or eight sieve stacks, each of which are arranged together in a supporting structure 4.

Above a tensioning device, which is not shown, there is a tensioning frame 7 with which the adjustable stops 5 are firmly connected. The lower pair of sieve frame ladder segments 1 is vertically movable and is guided by rollers 2 fastened to it and running on guide columns 3 which are firmly connected to the supporting frame 4. The upper pair of sieve frame conductor segments 1 a is rigidly connected to the supporting frame 4. Each sieve frame conductor segment 1 is loosely connected to the sieve frame conductor segment 1 a located above it via the adjustable stops 6. By actuating the clamping device arranged under the clamping frame 7, the sieve frames 8 are lifted one after the other from the bottom up. The air gap between the sieve frames 8 is overcome so that they lie one on top of the other and no longer on their support strips 9. When the distance between the adjustable stops 5 and the pair of sieve frame conductor segments 1 has been overcome and the uppermost one belonging to the pair of sieve frame conductor segments 1 has been placed on top Sieve frame 8 on the underlying one is moved upwards by the stops 5 in the further course of the tensioning process. This makes it possible to start the characteristic process of touching the sieve frames 8 with one another, flowing in sequence with the lowest sieve frame 8 belonging to the pair of sieve frame conductor segments ta, and to carry it out until the end.

Claims (7)

Claims 1.Sifter with a pair of sieve frame conductors per plan sifter compartment for holding sieve frames, which form a sieve stack when clamped together and rest on the sieve frame conductors in the relaxed state without mutual contact, characterized in that the sieve frame conductors are divided into pairs of sieve frame conductor segments lying opposite one another (1 ; 1a). 2. Plansifter according to claim 1, characterized in that only pairs of vertically movable sieve frame segments (1) exist in the plansifter compartment. 3. Plansifter according to claim t, 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 3rd CH678 288 A5 shows that the top pair of sieve frame ladder segments (1a) in the plan sifter compartment are immovable and the remaining pairs of sieve frame ladder segments (1) are vertically movable. 4. Plansifter according to claim 2 or 3, characterized in that the superposed and vertically movable Siebrahmenleitem segments (1) via rollers (2) on common guide columns (3), which are fixedly connected to a support frame (4), are guided . 5. Plansifter according to claim 2 or claim 3, characterized in that the minimum and maximum distance of the screen frame conductor segments (1; 1a) one above the other is adjustable in the relaxed state by adjustable stops (5) and (6). 6. Plansifter according to claim 5, characterized in that the adjustable stops (5) with a clamping frame (7) are fixedly connected. 7. Plansifter according to claim 6, characterized in that the distance between the stops (5) and the bottom pair of sieve frame conductor segments (1) is larger, up to an air gap between the relaxed sieve frame (8) than the sum of all air gaps among the relaxed Sieve frames (8) belonging to the pair of sieve frame conductor segments (1). 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 3rd