EP1034045B1 - Sieve cleaner for a plansifter - Google Patents

Abstract

The device has brush or knob-like cleaner heads (16). Most of the heads are positioned in a row. A distance bar (18) with fewer or without cleaner heads projects to one side from the head row. The distance bar is T-shaped relative to projecting arms (14) of the filter cleaner, which carry the cleaner head rows. The distance bar forms foot (26), which defines at least two support points. These are positioned at a relative distance on a straight line at right angles to the cleaner head row. The cleaner heads are pretensioned elastically against the filter covering.

Description

The invention relates to a combination of a sieve frame and at least one sieve cleaner for plan sifters, the sieve frame having a sieve covering and a bottom and the at least one sieve cleaner having a foot and brush-like or knob-like cleaning heads and moving erratically on the floor when the sieve frame is shaken , and a screen cleaner for such a combination.

Sieve cleaners are placed in the sieve frames of plan sifters so that they move along with the shaking movement of the sieve under the sieve covering and come into contact with their cleaning heads with the sieve covering to clean them.

In conventional screen cleaners, the cleaning heads are not in constant contact with the screen covering, but the cleaning effect is essentially due to the fact that the cleaning heads strike the screen covering. This is achieved, for example, in that the sieve cleaner is supported with one foot on a corrugated grating arranged parallel under the sieve covering and is thereby set in vibration as it moves over the corrugated grille.

From DE-C-873 345 a sieve frame of the type mentioned is known, in which the sieve cleaner is supported on the floor with its foot so tilted that only a part of the cleaning brushes abuts the sieve covering.

From EP 0 536 803 B1 a screen cleaner in the form of a three-armed star is known, in which the cleaning heads are arranged in the region of the free ends of the three cantilevered arms arranged at angular intervals of approximately 120 degrees. This sieve cleaner rests with one foot on the smooth sieve bottom. that he performs rocking movements during the shaking movement of the sieve and thereby strikes the sieve covering. The foot can engage in a floor scraper, which supports the removal of the sieve through to an ejection slot formed at the edge of the sieve frame.

This known screen cleaner has the advantage that it enables the screen frame to have a low overall height and, with its projecting arms, is good in the corners of the sieve frame can penetrate so that the sieve covering is also cleaned well in the corner areas.

When the sieve cleaner hits the edge of the sieve frame, the free ends of two arms come into contact with the edge of the sieve frame, while the third arm points towards the center of the sieve. The result of this is that the central area of the sieve is statistically swept by the cleaning heads more frequently than the edge areas. This can lead to an uneven cleaning effect and increased wear on the screen covering in the middle of the screen.

The object of the invention is to provide sieve frames and sieve cleaners with which an intensive yet gentle cleaning of the sieve covering can be achieved.

This object is achieved by a sieve frame according to claim 1 and by sieve cleaners according to claim 3 or 4.

Advantageous embodiments of the invention result from the subclaims.

In the sieve frame according to claim 1, all cleaning heads are resiliently biased against the sieve covering by a spring-supported foot, so that any dimensional tolerances in the distance between the sieve bottom and the sieve covering, for example as a result of a slight curvature of the sieve bottom, do not lead to jamming of the sieve cleaner ,

The cleaning effect is not achieved by blows against the fabric. but rather by the fact that the cleaning heads sweep over the screen covering. The absence of blows against the fabric is more than offset by the fact that all cleaning heads are constantly effective. Another advantage is that the cleaning heads are worn more evenly.

In the embodiment according to claim 6, the major part of the cleaning heads is arranged essentially in a row, and a spacer which is not or at least less densely populated with cleaning heads jumps to one side of the row of cleaning heads.

If the screen cleaner hits the edge of the screen frame, it can align itself so that the row of cleaning heads is almost parallel to the edge of the screen frame. In this way, a relatively large area of the screen covering is swept by the cleaning heads near the edge, while the spacer then projecting inward is less or not at all effective for cleaning. In this way, a more uniform cleaning of the screen covering is achieved on a statistical average and excessive wear of the screen covering in the area of the center of the screen is avoided.

The spacer is preferably not equipped with cleaning heads and is arranged in a T-shape with respect to the row of cleaning heads, and the foot with which the screen cleaner is supported on the smooth screen bottom and which can also serve as a floor scraper is designed under the spacer, that he touches the sieve bottom at at least two points. In this way, the range of motion of the screen cleaner is restricted in such a way that the entire row of cleaning heads is kept in constant contact with the screen covering.

The sieve frames of a plan sifter usually have an approximately square plan. A particularly uniform cleaning effect can be achieved if the length of the screen cleaner, measured from the row of cleaning heads to the free end of the spacer, is approximately half the edge length of the screen frame.

Preferred exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Figur 1

einen Siebreiniger der kein Ausführungsbeispiel der Erfindung ist, an dem jedoch einige Merkmale der Erfindung erläutert werden;

Figur 2

den Siebreiniger nach Figur 1 in einer Seitenansicht;

Figur 3

den Siebreiniger nach Figuren 1 und 2 in einer Ansicht von unten;

Figur 4

den Grundriß eines Siebrahmens eines Plansichters mit einem Siebreiniger, zur Erläuterung weiterer Teilaspekte der Erfindung;

Figur 5

einen vertikalen Schnitt durch den Siebrahmen nach Figur 4;

Figur 6

einen Teilschnitt durch einen Siebreiniger gemäß einem Ausführungsbeispiel der Erfindung;

Figur 7

einen Längsschnitt eines Siebreinigers gemäß einem weiteren Ausführungsbeispiel;

Figur 8

einen Siebreiniger gemäß einem weiteren Ausführungsbeispiel in der Draufsicht; und

Figur 9

einen Schnitt längs der Linie IX-IX in Figur 8.

Show it:

Figure 1

a screen cleaner which is not an embodiment of the invention, but on which some features of the invention will be explained;

Figure 2

the screen cleaner of Figure 1 in a side view;

Figure 3

the screen cleaner according to Figures 1 and 2 in a view from below;

Figure 4

the floor plan of a sieve frame of a plan sifter with a sieve cleaner, to explain further partial aspects of the invention;

Figure 5

a vertical section through the screen frame of Figure 4;

Figure 6

a partial section through a screen cleaner according to an embodiment of the invention;

Figure 7

a longitudinal section of a screen cleaner according to a further embodiment;

Figure 8

a screen cleaner according to another embodiment in plan view; and

Figure 9

a section along the line IX-IX in Figure 8.

The screen cleaner 10 shown in FIGS. 1 to 3 has an approximately T-shaped body made of rubber-elastic material. This body 12 forms two cantilevered arms 14, which are essentially aligned on a line and carry a plurality of cleaning heads 16 arranged in a row on the upper side. The cleaning heads 16 can be formed by knobs formed in one piece with the body or optionally also by tufts of bristles inserted into the body 12.

The body 12 also forms a spacer 18, which is arranged in a T-shape to the row of cleaning heads 16 and is offset somewhat downwards relative to the projecting arms 14. On the underside of the projecting arms 14, stiffening ribs 20 are provided which connect to one end of the spacer 18. At the opposite end, the spacer 18 has an upstanding projection 22, the upper end of which, however, is lower than the upper ends of the cleaning heads 16.

A foot of the screen cleaner is formed by two cams 24, 26 formed on the underside of the spacer 18. The cam 24 has a circular plan and is located near the end of the spacer 18 which faces the arms 14, while the cam 26 has an elongated plan and projects axially beyond the opposite end of the spacer 18.

While in the screen cleaner 10 according to Figures 1 to 3, the cantilevered arms are slightly angled. FIGS. 4 and 5 show a screen cleaner in which the arms 14 are connected to one another in a straight line and carry a continuous straight row of cleaning heads 16. Otherwise, the screen cleaner according to FIGS. 4 and 5 has the same structure as the screen cleaner according to FIGS. 1 to 3.

FIGS. 4 and 5 also show a sieve frame 28 of a plan sifter. This sieve frame has a smooth bottom 30 and is delimited by four walls 32, 34. Furthermore, the sieve frame 28 has a sieve covering 36, which is arranged at a distance parallel to the bottom 30. The wall 34 of the sieve frame forms with the bottom 30 an ejection slot 38 for the sieve diarrhea.

The screen cleaner 10 is supported with its cams 24, 26 aligned on a straight line on the smooth bottom 30 of the screen frame and is adjusted in height to the screen frame in such a way that all cleaning heads 16 rest on the underside of the screen covering 36, as in FIG 5 can be seen. Since the cams 24, 26 define a line of contact with the floor 30 that is perpendicular to the row of cleaning heads 16, the screen cleaner 10 itself could tip over this line of contact. However, this is prevented by the cleaning heads 16 bearing against the screen covering. The cams 24 therefore slide with their flat underside over the surface of the floor 30 and can thus act as a floor clearer. The height of the cam 26 is also such that it can also enter the output slot 38, as shown in FIG. 5.

Since the spacer 18 and thus also the cams 24, 26 are offset relative to the row of cleaning heads 16, the screen cleaner can tip over the cam 24. Usually, however, this is prevented by the center of gravity S of the screen cleaner being offset somewhat in the direction of the cam 26 with respect to the cam 24. If the screen cleaner should tip over in exceptional cases, for example in the event of violent vibrations, the pivoting range is limited in that the projection 22 is leaned against the screen covering. The screen cleaner 10 can also tip over if the distance between the bottom 30 and the screen covering 36 has changed due to warping or arching of the bottom 30. In this case, the tiltable support of the screen cleaner prevents jamming between the floor and the screen covering. A certain elastic flexibility of the arms 14 can also contribute to this.

FIG. 6 shows a screen cleaner according to the invention, in which the cam 24 is supported on the body 12 of the screen cleaner via a spring 40. In this way, the elastic pretension with which the cleaning heads 16 press against the screen covering 36 can be set very precisely.

The sieve frame 28 has an approximately square plan with an edge length a. The length L of the screen cleaner 10, measured from the row of cleaning heads 16 to the free end of the spacer 18, is approximately a / 2.

In the operation of the plan sifter, the sieve frame 28 is set in a shaking movement, so that the sieve cleaner 10 performs erratic movements on the floor 30. If the screen cleaner has approximately the orientation shown in FIG. 4, the cleaning heads 16 can clean the left half of the screen covering to the edge, but they cannot reach the right half of the screen covering, since the spacer 18 then abuts the wall 34 of the screen frame. If the screen cleaner has the opposite orientation, only the right half of the screen covering can be cleaned accordingly.

Since the length L of the screen cleaner is approximately half the edge length of the screen frame, there is neither a large gap nor a significant overlap between the two areas of screen covering that can be cleaned with the different orientations. The same applies correspondingly to orientations of the screen cleaner which are rotated by 90 degrees with respect to the orientation in FIG. 4. Since the orientations of the screen cleaner vary statistically, an approximately uniform cleaning and consequently also an approximately uniform wear of the screen covering is achieved on average over the entire surface of the screen covering. Due to the statistical nature of these considerations, high accuracy when dimensioning the length L is not important.

Figure 7 shows a further embodiment of a screen cleaner 10, which is constructed similarly to the screen cleaner of Figure 6, but in which the spring 40, which supports the cam 24, is not designed as a coil spring, but as an elongated leaf spring, which is in an elongated recess 42 lies on the underside of the body 12.

FIGS. 8 and 9 finally show a screen cleaner 10, the body 12 of which, similar to conventional screen cleaners, is designed as a flat plate which has a plan in the shape of an equilateral triangle with convexly rounded sides and is equipped with cleaning heads 16 on the entire peripheral edge. A cylindrical bushing 44 is formed centrally on the underside of the body 12, in which a piston forming the base 46 of the screen cleaner is guided such that it can move vertically. The spring 40 acting between the foot 46 and the body 12 is again designed as a helical spring and accommodated in the bushing 44.

The sieve cleaner according to FIGS. 8 and 9 is also supported with its foot 46 on the smooth sieve bottom, so that the cleaning heads 16 are pressed lightly against the sieve covering by the spring 40. Thus, all of the cleaning heads 16 are constantly active. If the sieve bottom has warped somewhat, the spring 40 can yield elastically so that the sieve cleaner does not jam in the space between the sieve bottom and the sieve covering.

The foot 46, like the body 12, can be made of rubber-elastic material. If the sieve cleaner moves in the sieve frame, it is possible to that the foot 46 "erases" on the smooth sieve bottom, so that slight vibrations are produced which support the cleaning effect.

Claims (10)

1. A combination of a sieve frame and at least one sieve cleaner for gyratory sifters, wherein the sieve frame has a sieve cover (36) and a floor (30), and the at least one sieve cleaner has a base (24, 26; 46) and brush or nap-like cleaning heads (16), and moves erratically on the floor (30) given a shaking motion of the sieve frame, characterized in that the base (46) or at least the part (24) of the base closest to the cleaning heads (16) supports the sieve cleaner via a spring (40), so that all cleaning heads (16) are resiliently pre-stressed against the sieve cover (36).
2. The combination according to claim 1, characterized in that the sieve cleaner is supported against the smooth floor (30) of the sieve frame (28).
3. A sieve cleaner for a combination according to claim 1 or 2, characterized in that the base (24, 26; 46) is offset relative to the cleaning heads (16), and the part (24; 46) of the base lying closest to the cleaning heads is located between these cleaning heads and the center of gravity (S) of the sieve cleaner.
4. The sieve cleaner for a combination according to claim 1 or 2, characterized in that the sieve cleaner is made out of an elastically resilient material, at least in the area of protruding arms (14) that carry the cleaning heads (16).
5. The sieve cleaner according to claim 3, characterized in that the sieve cleaner is made out of an elastically resilient material, at least in the area of protruding arms (14) that carry the cleaning heads (16).
6. The sieve cleaner according to one of claims 3 to 5, characterized in that the majority of cleaning heads (16) are essentially arranged in a row, and that a spacer (18) fitted less densely with cleaning heads, if at all, projects from the series of cleaning heads (16) to one side.
7. The sieve cleaner according to claim 6, characterized in that the spacer (18) is arranged in a T pattern relative to the protruding arms (14) of the sieve cleaner, which carry the row of cleaning heads (16).
8. The sieve cleaner according to claim 6 or 7, characterized in that the spacer (18) forms a base (24, 26) which in its entirety is offset relative to the row of cleaning heads (16), and defines at least two supporting points that lie spaced apart from each other on a line perpendicular to the row of cleaning bodies (16).
9. The sieve cleaner according to claim 8, characterized in that one free end of the spacer (18) has an upward projection (22) whose height is less than that of the cleaning heads (16).
10. A combination according to claim 1 or 2, with a sieve cleaner according to one of claims 6 to 9, characterized in that the length (L) of the sieve cleaner (10) measured from the row of cleaning heads (16) to the free end of the spacer (18) measures half the edge length (a) of the approximately square sieve frame.