US-12623252-B2 - Sieve and frame with improved connectability

US12623252B2US 12623252 B2US12623252 B2US 12623252B2US-12623252-B2

Abstract

A sieve, comprising outer bars and inner bars and sieving areas with sieving fabric being formed between the outer bars and the inner bars, wherein at least a portion of the outer bars is provided as elastomeric part and at least a portion of the inner bars is provided as elastomeric part, wherein said elastomeric parts can be transferred from a first untensioned state into a second tensioned state. The present invention is furthermore related to a sieve frame to which the sieve can be fixed in a tensioned state, as well as to a sieving device such as a plansifter comprising said sieve and/or sieve frame.

Inventors

Kevin Hausammann
Daniel Dörig
Jürgen Moosmann
Oliver SCHOCH

Assignees

Bühler AG

Dates

Publication Date: 20260512
Application Date: 20221220
Priority Date: 20211220

Claims (14)

1 . A sieve detachably securable to a sieve frame, the sieve comprising: at least one outer bar; at least one inner bar; and, a sieving fabric, wherein, a portion of the sieving fabric is disposed between the at least one outer bar and the at least one inner bar to form at least one sieving area; wherein at least a portion of the at least one outer bar comprises an elastomeric part and at least a portion of the at least one inner bar comprises an elastomeric part; and, wherein the elastomeric parts are transitionable between a first untensioned state and a second tensioned state.
2 . The sieve according to claim 1 , wherein the sieve comprises four outer bars that are connected so as to form a rectangle or a square, wherein the sieving fabric is disposed between the four outer bars, and wherein the at least one inner bar is arranged within said rectangle or a square, such that a plurality of sieving areas are formed.
3 . The sieve according to claim 1 , wherein the sieving fabric is integrally connected with the at least one outer bar and the at least one inner bar.
4 . The sieve according to claim 1 , wherein the elastomeric part of the at least one outer bar comprises a protrusion having a nose-like shape.
5 . The sieve according to claim 1 , wherein the elastomeric part of the at least one inner bar comprises a protrusion having a clip-like shape with two separate elongated portions extending away from each other.
6 . The sieve according to claim 1 , wherein the elastomeric part of the at least one outer bar extends along an entire length of the at least one outer bar.
7 . The sieve according to claim 1 , wherein the elastomeric part of the at least one inner bar extends along an entire length of the at least one inner bar.
8 . A sieve frame configured to detachably receive a sieve: the sieve frame comprising a side outlet area and a bottom plate, at least one outer profile, and at least one inner profile, wherein the at least one outer profile and at least one inner profile each comprise a respective groove proximate respective upper surfaces thereof, the sieve comprising at least one outer bar, at least one inner bar, and a sieving fabric, wherein, a portion of the sieving fabric is disposed between the at least one outer bar and the at least one inner bar to form at least one sieving area, wherein at least a portion of the at least one outer bar comprises an elastomeric part and at least a portion of the at least one inner bar comprises an elastomeric part, and wherein the elastomeric parts are transitionable between a first untensioned state and a second tensioned state, wherein, the sieve is detachably securable to the sieve frame by inserting the elastomeric parts of the sieve into the respective grooves of the at least one outer profile and the at least one inner profile of the sieve frame.
9 . The sieve frame according to claim 8 comprising a plurality of outer profiles, wherein the plurality of outer profiles are connected to each other via edges having an upper end and a lower end.
10 . The sieve frame according to claim 8 , wherein the sieve frame is made of stainless steel.
11 . A sieving device, comprising: a sieve frame comprising a side outlet area and a bottom plate, at least one outer profile, and at least one inner profile, wherein the at least one outer profile and at least one inner profile each comprise a respective groove proximate respective upper surfaces thereof, the sieve comprising at least one outer bar, at least one inner bar, and a sieving fabric, wherein, a portion of the sieving fabric is disposed between the at least one outer bar and the at least one inner bar to form at least one sieving area, wherein at least a portion of the at least one outer bar comprises an elastomeric part and at least a portion of the at least one inner bar comprises an elastomeric part, and wherein the elastomeric parts are transitionable between a first untensioned state and a second tensioned state, wherein, the sieve is detachably securable to the sieve frame by inserting the elastomeric parts of the sieve into the respective grooves of the at least one outer profile and the at least one inner profile of the sieve frame.
12 . The sieving device according to claim 11 , wherein more than one sieve frame is provided.
13 . The sieving device according to claim 11 , comprising a plan sifter of at least one of a food, an animal feed mill, a purifier, or a cleaning machine.
14 . The sieve according to claim 1 , comprising at least two inner bars that intersect one another, wherein the elastomeric parts of the at least two inner bars extend along a length of each of the plurality of each inner bar, except those portions of the plurality of the inner bars that one another.

Description

The present invention is related to a sieve and a frame with improved connectability. Sieves find widespread application in industrial applications where a separation or sorting of materials according to their particle size is required. As an example, plansifters may be mentioned. A plansifter, in particular a large plansifter or square plansifter, is a cube-shape device with large surface elements and is used to sift grist-, semolina- and flour-like products in the milling industry and for sorting of different grain types of cereals and the like. Sieves are provided in a plansifter that are set in an oscillating motion by means of a respective drive in the plansifter. In a plansifter, all possible sizes of sieve meshes are used, from approximately 60 μm upwards. For all of them it is equally important to achieve maximum sifting performance without sieve mesh clogging. The sieve fabric is provided in a pre-tensioned form on an insertion frame which is in turn inserted into a sieve frame which has a base plate and an outlet for fine material, and optionally as well as freely movable cleaning elements, as described e.g. in DE 197 06 601 C1, EP-0 584 302 B1, EP-0 330 846 A1 or U.S. Pat. No. 3,565,251 A and others. Several factors influence the operation of the plansifter. For example, a freshly spanned sieve fabric regularly works better, since not only the fabric wear but also the degree of tension of the sieve fabric is important. Exchanging a worn fabric is burdensome. First, the worn fabric has to be removed (ripped off). The so exposed surface has to be ground and freed from remaining glue and steel dust (in order to prevent corrosion). Then, glue has to be applied onto the cleaned surface, and a conditioned (under appropriate humidity conditions) fabric has to be fixed on the surface in a required tensioned state with the aid of said glue. Typically, users of plansifters are not capable of performing all those steps on site. Especially for the sieving of abrasive materials such as maize or sugar, there is no affordable solution which would allow for an easy replacement of worn sieve fabric. For example, it is known to use sieve stacks made of high-grade polyurethane in combination with stainless steel frame inserts. However, this concept still faces problems of corrosion (between the frame insert and the PU stack) when used for abrasive materials, as well as wear of the fabric. It was the problem underlying the present invention to overcome the problems of the above prior art and to provide a sieve system that can be easily replaced and is suitable for abrasive material. The above problem has been solved by the subject-matter of the claims. In detail, the present invention is related to a sieve, comprising outer bars and inner bars and sieving areas with sieving fabric being formed between the outer bars and the inner bars, characterized in that at least a portion of the outer bars is provided as elastomeric part and at least a portion of the inner bars is provided as elastomeric part, wherein said elastomeric parts can be transferred from a first untensioned state into a second tensioned state. The sieve according to the present invention can replace the insertion frames conventionally used in sieving devices such as plansifters. By the provision of portions of outer bars and inner bars of the sieve as elastomeric parts, said sieve may be firmly attached in a tensioned state onto an appropriate counter-part, preferably a sieve frame. The elastomeric parts are in a first untensioned state when the sieve is in a free state. When the sieve is to be attached onto an appropriate counterpart, preferably a sieve frame, the elastomeric parts may be inserted into respective counter-portions of said counter-part and thereby transferred from said first untensioned state into a second tensioned state. This results in a tensioning of the sieve (respective the fabric thereof) in an attached state, i.e. when the sieve is firmly attached to said appropriate counterpart, preferably sieve frame. The sieve according to the present invention can be easily removed from said appropriate counter-part, preferably sieve frame, by removing the elastomeric parts from the respective counter-portions of said counter-part. According to a preferred embodiment of the present invention, the sieve operates like a click-spring. The sieve according to the present invention has a general structure that is similar to an insertion frame of a conventional plansifter. In other words, the sieve comprises outer bars which form the outer boundaries of the sieve and enclose a sieving area. According to a preferred embodiment of the present invention, the sieve comprises four (4) outer bars that are connected so as to form a rectangle or a square. A rectangular form is preferred. In said rectangle or square, one or more inner bars are provided. Preferably, said inner bars extend from one outer bar to another opposite outer bar. According to a prefe