DE2061847A1 - Sieve design - with parallel rows of recessed slits - Google Patents

Abstract

The perforated or slitted plate carries the rows of parallel slits in the direction of material travel to separate disc-shaped solids from a fluid. The slits are recessed in a curved or angular cross-section to prevent blockage, while the solids build up on the flat strips between slit rows, and channels lead off the fluid.

Description

Sieve with protected openings for separating the liquid from a solid-liquid mixture The invention relates to a sieve for separating the liquid from a solid-liquid mixture consisting of a perforated or slotted sheet metal with a smooth surface.

To separate the liquid from a solid-liquid mixture, sieves of various kinds are used for. Example perforated, slotted or wedge wire screens. In order to achieve a large liquid flow with the smallest possible Attempts to reach the sieve area are the sieve openings of a sieve as a percentage To make the total area as large as possible. The upper limit is either the required one Minimum strength of the screen or there are manufacturing difficulties in the perforation.

The decisive factor for the sieve performance per unit area is once Difference in pressure on both sides of a sieve and the one that remains free Hole area on the solids side that is not covered by solids. If the solids rest immobile on a sieve with increasing liquid throughput time the remaining free opening of the sieve covered more and more, especially when the Solids contain small solid debris that follows the flow of juice between the large solid particles are flushed through and finally the opening channels in the solid itself as well as the contact surface of solid and sieve in their openings »« Hr and more clog. For this reason it is left in the solid room nearby the sieve movable scraper in the form of screws whether he boom passing by, which is a constant loosening of the solids above the sieve to the task to have. However, if the solids are largely in the form of discs, the sieving capacity will be particularly at risk because each disc lying flat on the sieve has a large number can cover by sieve holes.

The invention is based on the object of a sieve for a solid-liquid mixture with disk-shaped solid particles to create, the Screen surface, on which the goods are transported forms smooth and unperforated surfaces so that there are no protruding edges on which the material is scraped off during transport will.

This object is achieved in that the slots at a distance in The transport direction of the goods are one behind the other and parallel, adjacent ones Form rows of slots, and that the rows of slots from the level of the »sieve plate after are curved at the bottom.

As a result, smooth, continuous guide strips are formed on which the goods can be transported without damage. In addition, between the screen surface on which the discs lie and the slots formed channels, through which the liquid under the discs can get to the slots.

If such a sieve is now used with washers or, according to experience, with covered thread-like solids, then the solids-wet is mainly supported on the unperforated guide strips forming webs, whereby the slots or Holes are not, or only to a small extent, touched by the solid particles. The slotted or perforated Sieve parts are thus in channels, which keep a liquid path free for the sieve slots of each slot row.

Before-A special / part of the invention can also be seen in that no more scraped-off solid particles (pulp) get into the liquid.

The liquid stays cleaner. The wear (abrasion) of the solids sinks to a minimum. In addition, the sieve according to the invention offers a sufficient one Perforation to drain the liquid.

The disk-shaped solid bodies only rest on the unperforated Guide strips, if the mutual spacing of these guide strips is close enough is chosen to prevent the solids from sagging. The distance between the guide strips depends on the stiffness of the solid particles.

The performance of the sieve according to the invention is also protected lying sieve openings, even if the solid particles have a thread-like nature have shown a large-scale test in diffusion plants in the sugar industry. here could be a 2.4 square meter sieve with protected sieve openings with compared to a 7.4 square meter perforated sieve, the perforated sieve with maximum load worked. Although the large sieve cleaned about three times in two minutes and the sieve according to the invention only once at the same time, was the one supplied Amount of liquid in the sieve according to the invention with the sieve openings located in a protected manner with 58 cbm / sqm / h compared to 30.4 cbm / sqm / h with the usual vaulted sieve approx. 1QO X larger. The solids and liquid were the same in both cases, namely sugar beet pulp and raw sugar juice.

An exemplary embodiment is shown schematically in the drawing and is described in more detail below.

Show it:.

Fig. 1 is a plan view of the sieve according to the invention, 1 Fig. 2 a Section along lines A-B in Fig. 1, Fig. 3 shows a section along line C-D in Fig. 1 Fig. 4 shows a further embodiment of the sieve according to the invention.

The sieve according to the invention consists of a sieve plate 1 with the sieve surface 2. In this sheet .sind one behind the other in the direction of transport of the goods Punched slots 3. Instead of the rectangular slots shown in FIG oval slots or bores close to one another can also be provided will. Several of these slots 3 lying one behind the other form a row of slots 4. Several of these rows of slots 4 to 8 are transverse to the direction in which the goods are transported provided parallel and side by side.

These rows of slots 4 to 8 are out of the plane of the sieve plate 1 after bent down so that between the slots 3 and the surface 2 of the screen plate 1 liquid channels 19 are formed.

The rows of slots can either be curved (as shown in Fig. 2) or be folded (as shown in FIG. 4). Particularly beneficial is at the angular bend when the rows of slots 4 to 8 each one to the screen surface 2 have parallel bottom piece 9, which by means of inclined Side pieces 10 and 11 are connected to the screen plate 1, the side pieces 10, 11 under one Angles to the screen surface of about 450 run, Between the downward-curved rows of slots 4 to 8 are located in the direction of transport of the goods running unperforated guide strips 12 to 17, all together the Form the total guide surface for the solids. These from the guide strips 12 to 17 formed guide surface absorbs the entire pressure of the goods, so that the slots 3 are relieved of pressure. Those lying below the screen surface 2 Slits 3 are consequently relieved of pressure and are only used for liquid discharge.

The total area of the non-perforated guide strips 12 to 17 to The total screen area must be chosen so large that the contact pressure of the solids on the unperforated guide strips not to be scraped off or cut into the individual guide strips can lead into the solids. The harder the solids are, the narrower the guide strips 12 to 17 can be. The spacing of the individual guide strips 12 to 17 from each other should only be so large that the solid Particles cannot bend and thus the slots would add. This means that the distances between the guide strips are at compliant solids must be small. For fabrics with high stiffness the Solids can increase these distances. These distances, or the length L the slots 3 are of different sizes depending on the nature of the solids.

In particular in the sugar industry, instead of the disc-shaped Solids also used thread-like sugar beet pulp. When using thread-like material, the width B of the slots 3 must be narrower than the thickness of the single threads. In addition, the screen structure remains the same even with thread-like material as described above.

In Fig. 1, a scraper 18 is shown in dashed lines, which is attached to the Sieve surface 2, so on the solids side over the sieve level in any Way is moved.

As shown in FIG. 4, the liquid is withdrawn through the sieve resulting pressure in the solid-liquid mixture largely due to the unperforated guide strips 12 to 17 added at the angle of slope of the solids, whereby the rows of slots 4 to 8 are relieved of pressure and thereby large amounts of liquid can discharge unhindered from the solid-liquid mixture.

Claims (8)

Claims 1. Sieve for separating the liquid from a solid-liquid mixture, consisting of a perforated or slotted sheet metal with a smooth surface, thereby characterized in that the slots (3) at a distance in the direction of transport of the goods one behind the other and parallel rows of slots lying next to one another at a distance (4 to 8) form, and that the rows of slots (4 to 8) out of the plane of the sieve plate (1) are bent downwards. 2. Sieve according to claim 1, characterized in -that the downward curved rows of slots (4 to 8) are formed in a curve or arc shape. 3. Sieve according to claim 1, characterized in that the downward curved rows of slots (4 to 8) are edged. 4. Sieve according to claims (1 and 3), characterized in that the rows of slots (4 to 8) each one to the screen surface (2) parallel having running bottom piece (9), which by means of inclined side pieces (10,11) are connected to the sieve plate (1). 5. Sieve according to claim 4, characterized in that the side pieces (10,11) run at an angle otvon about 450 to the screen surface (2). 6. Sieve according to claims 1 to 5, characterized in that the unperforated guide strips between the rows of slots (4 to 8) (12 to 17) form, the total area of which is so large to the total screen area that the Contact pressure of the solids on the guide tires (12 to 17) scraping off the Solids or cutting the individual guide strips into the solids prevented. 7. Sieve according to claim 6, characterized in that the distances of the individual guide strips (12 to 17) from each other depending on the strength of the solids are so large that the solid matter lying on the guide strips (12 to 17) Particle do not bend. 8. Sieve according to claims 6 and 7, characterized in that the Width of the guide strips (12 to 17) is adapted to the hardness of the solids.