LV11672B - Ierīce granuIešanai, granuiešanas paņēmiens un granulēts produkts - Google Patents

Abstract

Izgudrojums attiecas uz granuiešanas iekārtu, kas satur sajaukšanas cilindru (I), kurš apgādāts ar pulvermateriāla padeves līdzekli, līmvielas padeves ierīci un izejasatveri granulētā materiāla aizvākšanai no cilindra, izkliedētājlīdzekli, kuram ir iekšējā telpa un kurš izvietots maisītāja cilindrā, un kuram pievienota līmvielas padeves ierīce tā, lai līmvielu varētu izkliedēt maisītāja cilindrā caur izkliedētājlīdzekli, ar izkliedētājtīdzeklisavienotas maisītājldetaļasgranulējamā materiāla maisīšanai sajaukšanas cilindrā. Izkiiedētājlīdzeklim ir apvalks ar caurumiem, ar kuru palīdzību no līmvielas padeves ierīces izkliedētājlīdzekli ievadīto līmvielu var izkliedēt sajaukšanas cilindrā. Izgudrojums attiecas arī uz pulverveida granulēšanas paņēmienu un arī uz iegūto produktu.

Description

The present invention concerns a granulating apparatus for granulating powdery material, a powdery material granulating procedure and a granulated product, as defined in the preambles to Claims I, 9 and 18.

The invention is in particular associated with mixing granulation tn which particles of a powdery material are made adherent to each other in a mixing process by effect of a bonding agent.

The mixing granulation method has been found to be a usable granulating procedure e.g. in granulating mineral feeds. Mineral feed mixtures meant for meeting the mineral requirements of animals and containing no actual fodder value are mainly composed of inorganic calcium, phosphorus, magnesium and sodium sources and of sources о Г vitamins and trace elements. Sodium gluconate has been used with success for bonding agent in granulating mineral feed mixtures (see the patent. FI-86134). Molasses have been added to the bonding agent solu Lion mainly in order to improve the flavour of the mixture.

Granulation may be implemented with a granulating apparatus comprising a mixing drum, provided with a feed member for introducing the powdery material which is to be granulaLed, with a bonding agent solution feed member and with a granulated material withdrawing aperture, and a distribution member, placed inside the mixing drum and. to which the Loading agent solution feed member has been so connected that the bonding agent solution can be fed into the mixing drum through the distribution member. In conjunction with the distribution member, mixing members have been provided for mixing the material to be granulated, in the mixing drum.

For instance, in an apparatus used Ln granulating mineral feed mixtures, the distribution /member is a cylindrical body having an interior volume and 5 rotating about its rotational axis, this body being formed of several flanges and several sleeves positioned against each other so that in the outer shell of the distribution member are defined several annular gaps delimited by said flanges, through which the 10 bonding agent solution is distributed into the mixing drum. The width of one annular gap is e.g. 0.5 mm. The mixing members are placed on the outer shell of the distribution member. The distribution member and mixing drum are furthermore arranged to rotate relative 15 to each other, whereby the actual mixing takes place by effect of this rotation, while the mixing members enhance the mixing.

Tn the granulation process powdery mineral feed mixture is thus fed into a rotating mixing drum.

Simultaneously, one or several bonding agent solution components, such as sodium gluconate and molasses, arc supplied into the rotating distribution member, whence the bonding agent components, becoming mixed together, are distributed by action of centrifugal force, 25 through the gaps of the distribution member, in among the surrounding dry feed nix. The particles of the powdery mixture become adherent to the bonding agent in this mixing, and desired granulation takes place. The granular product thus obtained is conducted from 30 the mixing drum to further processing steps.

However, problems are encountered in connection wi Lh the granulating apparatus used at present. Mass which consists of mineral mix and bonding agent accumulates in a comparatively short running Lime On 35 the walls of the mixing drum and on the distribution member, particularly on the mixing members thereof, building up to an exceedingly hard and uneven surface, which has. to be removed from time to time to enable proper operation of the apparatus. Lt is also noted that the annular gaps of the distribution member are plugged very soon.

Cleaning of the apparatus is awkward, and slow, owing to the petrified nature of the indurations, thus causing prolonged shut-downs. The cleaning also wears down the surfaces of walls, distribution member and mixing members. Surface defects attendant on cleaning tend to accelerate the wear in use of all surfaces. For instance, mixing members which have suffered surface damage wear down rapidly in use and have to be replaced. Furthermore, as the mixing members become worn, feed mix comes ever easier into contact with the annular gaps.

The costs arising from maintenance of the apparatus, i.e., from cleaning and replacement of components, constitute therefore a significant proportion of the production cost.

The object of the present invention is to eliminate the drawbacks mentioned.

The object of the invention is to disclose a novel granulating apparatus thanks to which the production costs associated with mixing granulation, in particular mineral feed granulation, can be significantly reduced from their previous level.

It is a further objective of the invention to disclose a novel granulating apparatus in which owing to novel disposition of its distribution member plugging of the apparatus and accumulation of mass on its surfaces, particularly when granulating mineral feeds, is less than before.

It is a further objective of the invention to disclose a novel procedure for granulating powdery material, this procedure enabling good quality granules to be obtained, with good yield. The objective of the invention is furthermore to disclose a product granulaLed by the procedure.

Regarding the features characterizing Lhe invention, reference is made to the claims. i

The invention is based on a novel disposition of the distribution member in the granulating apparatus intended for mixing granulation. In the apparatus of the invention, the distribution member having an interior volume comprises a shell with holes, whereby the bonding agent solution conducted from a bonding agent solution feed member into the distribution member can be distributed into the mixing drum through the holes in said shell.

In studies associated with the invention the surprising observation was made that the way in which the bonding agent discharges from the distribution means has an unexpectedly high significance in view of the problems encountered in connection with the use of the granulating apparatus. Examination of a distribution member provided with an annular gap, consistent with the state of art, revealed that the bonding agent discharges from the gap in film fashion, and the emerging bonding agent film is not always uniformly distributed among the surrounding powdery material: it rather forms splashes on the mixing members und on the walls of the mixing drum. These splashes appear to be the major cause of the material accumulation described in the foregoing. Further, according to Lhe studies, the liquid pressure goes down considerably in the annular gap, on the way from the interior of the distribution member to the outer periphery. For this reason powder dust may enter the annular gaps, where it is compacted together with the bonding agent solution to form a plug.

In studies of the apparatus set-up of the invention the observation was made that e.g. in connection with granulating mineral feeds the accumulation of material deposits on the walls of the mixing drum and on the mixing members was less than before, whereby the wear of the blades was also slower. One of the causes responsible for this favourable effect is suggested to be that as a consequence of Lhe hole arrangement in the distribution means lhe bonding agent solution is mainiy discharged in the Corm of droplets and/or in jet fashion, whereby there will be less splashing which becomes adherent to the surfaces, compared with film-type discharge. It was further noted Lhat in the distribution member оГ the invention the plugging of holes during operation is Less than expected. Thus, the resistance to wear, and functioning, of the apparatus of the invention are superior to those of any apparatus of prior art.

The holes with which the distribution member of the apparatus of the invention is provided may be equal or unequal in size, and their diameter is advantageously in the range about 0.2 to 2 mm, suitably about 0,3 to 1.5 mm. The shape of the holes may be substantially circular or elliptical, but it is not confined to these shapes.

On the outer shell of the distribution member is advantageously provided at least one region furnished with holes and at least one region which has no holes .

Furthermore, the outer diameter of the distribution member may be larger in lhe regions without holes than in the perforated regions, whereby the regions without holes serve as elevated buffer protection against powdery material lending to cause attrition and to plug holes.

According to an advantageous embodiment, the distribution member is cylindrical and comprises al least two perforated regions, disposed to constitute annular perforated zones on the whole length of the distribution member’s shell. The perforated zones alternate with zones having no holes. The breadth, hole density and hole size may vary between perforated zones.

Since the mode of discharge of bonding/ agent, solution attained with the aid of the perforations is essential in view of the invention and since it is evident to a person skilled in the art thaL the shape and size of the perforated region(s) can be enlisted to influence e.g, the distribution of the bonding agent in different parts of the distribution member’s shell and the quantity of bonding agent distributed, IL is not expedient to restrict the hole arrangement to the dispositions here presented only: any other dispositions are equally within the scope of the invention.

In the apparatus of the invention, the mixing members are advantageously connected to the outer shell of the distribution member, but lhey may equally be disposed separately from the distribution member. The shape, size, number and placing of the mixing members may, for instance, be consistent with common practice known in connection with mixing members. According Lo an advantageous embodiment, the mixing members are arm-like, straight or bent, and they are advantageously disposed in a region containing no perforated zones along Lhe outer shell of the distribution member so that their outward pointing arm part extends in over a perforated region. The advantage from such disposition is that in addition to its mixing function the mixing member serves as protection for the holes thereunder and for the bonding agent solution jet discharging through the holes.

(n the apparatus of the invention, lhe distribution member is advantageously disposed to rotate about its rotational axis parallelling lhe longitudinal axis. Further, the distribution member is placed in the mixing drum of the apparatus, which is provided with a powdery material feeding member,· a bonding agent solution feeding member and an exiL aperture.

The mixing drum may be a container of any shape whatsoever known in the art. such as a cyl/indrical vessel. It is advantageously disposed to be rotatable in relation to the distribution member in order to produce efficient mixing, but other kinds of mixing arrangement can be contemplated as well, such as providing said container with mixing members.

The powdery material feeding member consists of a pipe and feed apparatus arrangement disposed in conjunction with the mixing drum in accordance with common practice of the art. For feeding apparatus e.g. a screw conveyor or a pump can be used.

The bonding agent solution feeding member consists of a pipe and feed apparatus arrangement provided in conjunction with the mixing drum in accordance with common practice in the art. For feeding apparatus e.g. a pump can be used. The pipe arrangement communicates with the interior space of the distribution member.

The mixing drum is advantageously provided with a separate, finished product exit aperture. In the case of a rotating mixing drum, to said exit aperLure may be connected, in the way known in the art, a zigzag-shaped tube, which may rotate Ln conjunction with the mixing drum.

The invention furthermore discloses a procedure for granulating powdery material, as has been stated in Claim 9, the bonding agent solution being distributed into the powdery material substantially surrounding the distribution member, through holes provided tn the shell of the distribution member.

The mixing drum and distribution member are advantageously rotated in relation to each other, the directions of rotation being opposite. Hereby requisite, powerful mixing is achieved i.n the granulation process.

In the procedure of the invention, distribution of the bonding agent solution through the holes of the distribution member into the mixing drum x?an be carried out according to common pracLice in the art 5 with the aid of centrifugal force produced by the rotation of the distribution member and/or by feeding bonding agent solution under pressure into the distribution member. Tn order to improve the flowing quality of the bonding agent solution, the solution may be TO warmed up prior to introducing it in the distribution member .

The procedure of the invention is generally applicable with any powdery material that has to be granulated with bonding agent. The bonding agent solu15 tion may contain one or several components, as known in the art.

The procedure of the invention is particularly suited to be used e.g. in granulating mineral feeds with the aid of bonding agent solution, which advan20 tageously contains sodium gluconate and possibly molasses .

Mineral feed mixes are understood to mean mixtures with ample content, that is more than onehalf, suitably more than 75% hy weight, advantageously 25 more than 90% by weight, of mineral substances, that is physiologically tolerable inorganic substances known in themselves in the art. Regarding the mixture formulations, the bonding agent solution used in the procedure and the concentration, reference is made 30 e.g. to the Patent FI 86134, The bonding agent solution may in addition to those mentioned also contain other components. Bonding agent solution is added lo the mineral feed mix to be used e.g. at 1.5 to 25% by weight. The granulated product may be finished with a 35 so-called powdering substance, e.g. with lime and/or talc. The size of the granules of the product granulated as taught by the invention varies in the range of about 1· to 7 mm, advantageously about 2 to 5 mm.

The invention furthermore discloses a granular mineral feed mixture prepared according to the invention.

The granulated product of the invention is more homogeneous, that is less caking, compared with products prepared by procedures of prior art.

The procedure of the invention is advantageously implemented by means of the apparatus of the invention. Thanks to the apparatus of the invention, the cleaning and maintenance requirements of Lhe apparatus have gone down e.g. in a mineral feed granulating process from what they were heretofore; this in15 creases the production capacity and reduces the maintenance costs.

The invention is described in detail in the following, referring to the drawings, wherein

Fig. 1 presents a favourable apparatus according to 20 the invention.

Fig. 2 presents, partly sectioned, the distribution member of an advantageous apparatus of lhe invention. Fig. 3 presents the hole spacing in one perforation zone of a distribution member, and

Fig. 4 shows, sectioned, the distribution member of an apparatus conforming to prior art.

The feed granulation apparatus of Fig. 1 comprises a tubular mixing drum 1, one end of which is provided with a powdery material, feeding member 2 and 30 with a bonding agent solution feeding member 3 and the other end, with an exit aperture 4 for removal of granulated material from the drum 1. Within the mixing drum 1 has heen placed a distribution member 5, provided with an interior space, to which the bonding 35 agent solution feeding member 3 has been so connected that the bonding agent solution can be distributed tn the mixing drum 1 through the distribution member 5.

The.diameter ratio of the distribution member 5, made of wear-resistant material such as stainless steel, and the mixing drum 1 is, for instance, consistent with common practice applied in connection with such apparatus. The distribution member 5 and mixing drum 1 are disposed to be rotatable in relation to each other so that they can be rotated around their longitudinal rotational axis in opposite directions. However, drum and distribution member may equally be disposed to rotate in the same direction, or so that only one of them can be rotated, either the distribution member or the mixing drum. The mixing drum 1 is advantageously arranged to be eccentric, but it may equally be disposed to rotate around its longitudinal central axis. The apparatus includes drive means, such as electric motors 8 and 9, for rotating the mixing drum and the distribution member.

On the exit aperture is provided a zigzagshaped tube 16, known in the art, which rotates in conjunction with the mixing drum.

In Fig. 2 is in greater detail presented the distribution member 5 of an advantageous apparatus according to the invention. The distribution member 5 consists of a cylindrical body 17 having an interior space and on the shell 6 of which have alternatingly been provided three perforated zones 14 and four zones 15 containing no holes. On the end of the apparatus extending into the mixing drum L has been affixed a cover 20, with the aid of a fixing member 21. The other end of the distribution member 5 is with juncture members 18, e.g. with a flange union, connected in conjunction with the bonding agent solution feeding member 3 in such manner that the bonding agent solution can be supplied along a tube belonging to the feeding member 3, into the distribution member.

In the perforated zones 14, the holes 10 have been disposed in a plurality of circumferential rows.

The diameter of the holes in the perforated zone 14 adjacent to the bonding agent solution feeding member 3 and of those in the centremost perforated zone is about 0.5 mm, and the hole diameter in the perforated zone 14 adJacenL to Lhe end of the distribution member 5 extending into the mixing drum 1 is 1.0 mm. The number of holes in each zone is so selected that the aggregate hole area is approximately the same tn al 1 zones 14.

Tn Fig. 3 is depicted an advantageous hole spacing pattern in the perforated zone, comprising eight circumferential rows of holes 10 having diameter about 0.5 mm. The row spacing is 7 mm, and the spacing of the holes tn a row is 5 mm. In the zone altogether about 1600 holes have been provided.

In the distribution member 5 of Fig. 2, the zones 15 containing no holes have been formed of separate annular hoops 19 fixed on the body of Lhe distribution member by any fixing mode known in the art, which hoops can be detached from the cylindrical body of the distribution member 5 and which establish an attrition buffer protecting the perforated zones 14 lying in the depressions between them.

The mixing members 7 are attached to the zones 15 without holes with regular spacing, e.g. 2 to

16. such as four, mixing members to each zone (in Figs I and 2 only part of the mixing members 7 are depicted). The mixing member 7 has V or Y shape, but. it may equally be bent in another way, or straight, or for instance as shown in Fig. 4. In the embodiment of Fig. 2 the mixing members 7 extend above the perforated zone L4, whereby in operation they contribute to protecting the perforated zone 14.

According to the invention, the distribution member 5 may advantageously consist of one cylindrical body piece, the holes in its shell having been produced e.g. by drilling or, advantageously, using Laser machining. The regions containing no holes may be unperforated portions of the shell, or they may for instance be created of separate, detachable hoops as described in the foregoing.

In Fig. 4 is presented the distribution member of a granulating apparatus conforming to the state of art, which is provided with annular slit zones 22 and with mixing members 7 placed on either side of the slit zone.

Example 1: Granulating a mineral feed mix

In the following, a granulating procedure according to the invention is described in which the 15 apparatus of the invention is employed in continuous operation. The powdery mineral feed mix is supplied into the rotating mixing drum 2 wi th a screw conveyor through a pipeline 2 leading into the mixing drum 1. AL the same time, sodium gluconate and molasses, heat20 ed to about 40*0, are separately pumped into the distribution member 5 under about 4 bar pressure by pipes

3. With the aid оГ the supply pressure and of centrifugal force, the sodium gluconate and molasses, which have become mixed, are forced out from the rotating 25 distribution member through holes 10 in the shell, in among the mineral feed mixture arriving in the mixing drum .1 and substantially surrounding the distribution member 5. As the mixing drum 1 rotates in the direction opposite Lo the rotation of the distribution mem30 ber 5 and the mixing members 7 on the distribution member enhance the mixing process, the liquid droplets condense in the powder dust to crystals, and the crystalline product flow moves into the rotating zigzag tube part 16, where the granules grow further and 35 where the product is moreover finished with Lime. The finished product is rinally conducted to further processing. The granules thus obtained are good in quail ty. and caking is minimal. The grain size of the completed product Is about 2 to 5 mm. advantageously about 3 mm. The procedure may equally be Implemented as a batch process.

When the apparatus of the invention is being used, the apparatus need not be cleaned as often as an apparatus conforming to the state of art. Moreover, the distribution member of the invention is less subject to wear and to plugging than before.

The granulated mineral feed mixture preparations following below, intended for neat cattle and pigs, are produced by the procedure presented in Example 1. The solid matter contents of the sodium gluconate and molasses used were about 50% by weight.

Claims (18)

1. IZGUDROJUMA FORMULA

   I. Granulēšanas iekārta, kas satur sajaukšanas cilindru (1), kurš apgādāts ar pulvermatriāla padeves līdzekli (2), līmvielas padeves ierīci (3) un izejas atveri (4) granulētā materiāla aizvākšanai no cilindra; izkliedētājlīdzekli (5), kuram ir iekšējā telpa un kurš izvietots sajaukšanas cilindra iekšpusē, un kuram pievienota līmvielas padeves ierīce tā, lai līmvielu varētu izkliedēt sajaukšanas cilindrā caur izkliedētājlīdzekli; ar izkliedētājlīdzekli savienotas maisītājdetaļas (7) granulējamā materiāla maisīšanai sajaukšanas cilindrā, atšķiras ar to, ka izkliedētājlīdzeklim (5) ir apvalks (6) ar caurumiem (10), ar kuru palīdzību no līmvielas padeves ierīces (3) izkliedētājlīdzekli ievadīto līmvielu var izkliedēt sajaukšanas cilindrā caur apvalka caurumiem.
2. 2.Iekārta saskaņā ar 1 .p., atšķiras ar to, ka iekārta satur piedziņas līdzekļus (8,9) sajaukšanas cilindra (1) un izkliedētājlīdzekļa (5) rotācijai attiecībā vienam pret otru.
3. 3.lekārta saskaņā ar 2.p., atšķiras ar to, ka apvalks (6) aprīkots ar vienāda vai dažāda izmēra caurumiem, pie kam caurumu diametrs ir 0,2 līdz 2 mm.
4. 4.Iekārta saskaņā ar jebkuru no 1.-3.p.p., atšķiras ar to, ka izkliedētājlīdzekļa (5) apvalkā (6) ir vismaz viena zona (12) ar caurumiem (10) un vismaz viena zona (13) bez caurumiem.
5. 5.Iekārta saskaņā ar jebkuru no 1.-4.p.p., atšķiras ar to, ka apvalkā ir vismaz divas perforētās zonas (14), kuras mainās ar vismaz trīs zonām (15), kuras nesatur caurumus.
6. 6.Iekārta saskaņā ar jebkuru no 1.-5.p.p., atšķiras ar to, ka izkliedētājlīdzekļa (5) ārējais apvalks (6) ir aprīkots ar maisītājdetaļām (7).
7. 7.lekārta saskaņā ar jebkuru no 1.-6.p.p., atšķiras ar to, ka maisītājdetaļas (7) ir rokveida formas, taisnas vai izliektas un tās ir pievienotas virzienā uz ārpusi attiecībā pret ārējo apvalku (6) un plešas virs zonas (12), kurā ir caurumi. ...
8. 8.Iekārta saskaņā ar jebkuru no 1 .-7.p.p., atšķiras ar to, ka iekārta satur izejas atveres (4) paplašinājuma formā izveidotu zigzagveida cauruli (16), kura rotē ap savu rotācijas asi.
9. 9. Pulvermateriāla granulēšanas paņēmiens, saskaņā ar kuru granulējamo pulvermateriālu ievada sajaukšanas cilindrā; līmvielu izkliedē ar izkliedētājlīdzekli ievadītajā pulverveida materiālā tādā veidā, ka pulvermateriāls pilnībā apņem izkliedētājlīdzekli, un materiālu maisa, lai panāktu granulāciju; tādējādi iegūto granulēto produktu no samaisīšanas cilindra pēc tam aizvāc tālākai apstrādei, atšķiras ar to, ka līmvielu izkliedē caur izkliedētājlīdzekļa caurumiem starp pulvermateriāla daļiņām.
10. 10. Paņēmiens saskaņā ar 9. punktu, atšķiras ar to, ka izkliedētājlīdzekis un sajaukšanas cilindrs rotē attiecībā viens pret otru.

    II. Paņēmiens saskaņā ar 9. vai 10.punktu, atšķiras ar to, ka līmvielu izkliedē caur rotējošā, galvenokārt cilindriskas formas, izkliedētājlīdzekļa apvalkā esošajiem caurumiem.
11. 12. Paņēmiens saskaņā ar jebkuru no 9.-11.p.p., atšķiras ar to, ka līmvielu, iespējams uzkarsētu, zem spiediena ievada rotējošajā izkliedētājlīdzekli.
12. 13. Paņēmiens saskaņā ar jebkuru no 9.-12.p.p., atšķiras ar to, ka granulējamais materiāls tiek jaukts izmantojot maisītājdetaļas, ar kurām ir aprīkots izkliedētājlīdzeklis.
13. 14. Paņēmiens saskaņā ar jebkuru no 9.-13.p.p., atšķiras ar to, ka nolūkā palielināt graudu lielumu, no sajaukšanas cilindra izejošo granulēto materiālu ievada zigzagveida caurulē, kura rotē kopā ar sajaukšanas cilindru.
14. 15. Paņēmiens saskaņā ar jebkuru no 9.-14.p.p., atšķiras ar to, ka par pulvermateriālu izmanto minerālbarībai paredzētu pulvermaisījumu.
15. 16. Paņēmiens saskaņā ar 15.p., atšķiras ar to, ka līmviela satur nātrija glikonātu un, iespējams, melasi.
16. 17. Paņēmiens saskaņā ar 15. vai 16.punktu, atšķiras ar to, ka iegūto minerālbarības produktu, kas vēlāk var tikt apstrādāts, izžāvē ar precizitāti mazāk par apmēram 4%, ieteicamāk ir mazāk par apmēram 2% no svara, rēķinot uz sausni. ..
17. 18. Granulētais produkts, kurš sagatavots ievadot granulējamo pulvermateriālu sajaukšanas cilindrā; līmvielu izkliedējot ar izkliedētājlīdzekli, kuram ir iekšēja telpa, tādā veidā, ka pulvermateriāls pilnībā apņem izkliedētājlīdzekli, un maisot materiālu, lai panāktu granulāciju; tādējādi iegūto granulēto produktu no sajaukšanas cilindra pēc tam aizvācot tālākai apstrādei, atšķiras ar to, ka granulētas minerālbarības iegūšanai līmvielas izkliedēšanai lieto izkliedētājlīdzekli, kura apvalkā ir caurumi.
18. 19. Produkts saskaņā ar 18. punktu, atšķiras ar to, ka produkts ir granulēta minerālbarība, kas satur 3 līdz 20% līmvielas, ieteicamāk 6 līdz 15%, rēķinot uz gatavā produkta svaru.