US2779474A

US2779474A - Continuously operating centrifugal machine

Info

Publication number: US2779474A
Application number: US435319A
Authority: US
Inventors: Herman J Van Wezel
Original assignee: Individual
Current assignee: Koninklijke Machinefabriek Stork BV
Priority date: 1953-06-19
Filing date: 1954-06-08
Publication date: 1957-01-29
Anticipated expiration: 1974-01-29
Also published as: CH324796A; BE529573A; NL179252B; DE944000C; FR1110309A; NL79419C

Description

Jan. 29, 1957 H. J. VAN WEZEL 2,779,474

CONTINUOUSLY OPERATING CENTRIFUGAL MACHINE Filed June 8, 1954 2 Sheets-Shes? l Jan. 29, 1957 H. J.'VAN WEZEL CONTINUOUSLY OPERATING CENTRIFUGAL MACHINE 2 Sheets-Sheet 2 Filed June 8, l954 U i W I CONTINUOUSLY OPERATING CENTRIFUGAL MACHINE Herman J. van Wezel, Hengelo, Netherlands, assignor to Koninklijke Machinefabriek Gebr. Stork & Co. N. V., Hengelo, Netherlands Application June 8, 1954, Serial No. 435,319 g I Claims priority, application Netherlands June 19, 1953 3 Claims. (Cl. 210-69) This invention relates to a continuously operating centrifugal machine, having a screen drum, into which the mass to be treated is continuously supplied and in the screen drum of which a scraper device rotates with an angular velocity slightly differing from that of the screen drum. I

Centrifugal machines of this kind are known in which the solid substance separated in the screen drum is continuously conveyed along the screen wall towards the discharge end of the drum by the scraper device so that the scrapers also act as conveyor blades. In order to obtain said conveying action the scrapers have to exert a heavy pressure in axial direction on the solid particles for over coming the centrifugal action so that danger of damaging the solid particles arises. Particularly with crystalline masses, such as sugar, damage .of the crystals is a serious drawback.

The invention has for its object to improve a centrifugal machine of the kind referred to in such a manner that the layer of solid particles deposited on the drum wall may be scraped off continuously at full speed of the drum and be conveyed towards the discharge without be coming damaged. According to the invention the mass to be treated is supplied into the screen drum along the whole height of the screen wall by one or more feed members which rotate together with the scraper device consisting of one or more scrapers operating along the whole height of the drum closely to the drum wall and loosening the deposited layer from the wall, the scraper or each scraper being provided with one or more nozzles discharging a compressed medium blowing the solid particles scraped off from the screen wall towards the discharge end of the drum. As with said arrangement the scrapers do not exert a conveying action the power consumption will be small and the solid particles will not be damaged.

The invention will be further described with reference to the accompanying drawings illustrating an embodiment of the centrifugal machine according to the invention.

Fig. l is a sectional elevation of the machine taken along the broken line II of Fig. 2.

Fig. 2 is a horizontal section taken along the line H- II of Fig. l.

The centrifugal basket or drum 2 is secured on the shaft 1 with its hub 3. The inner wall of the drum is constituted by a screen wall 4 consisting of rings. Said rings leave small slots with respect to each other for the passage of the liquid to be separated and are centered by vertical ribs 5 secured to the inner side of the drum. The outer wall of the drum 2 is conically widened in upward direction so that the liquid thrown on said wall is moved upwards by the centrifugal action and flows over the rim 6 into the gutter 7 at the inner side of the stationary outer drum 8.

The shaft 1 is surrounded by a hollow shaft 9 which at its upper end and its lower end is guided by bearings 10 on the shaft 1 and supported by an axial bearing 11. The

2,779,474 Patented Jan. 29, 1957 hollow shaft 9 carries a drum 12 having an oval cross section and connected to the shaft by a bottom plate 13. Two diametrically opposed flat boxes 14 are secured to the oval drum 12 at its largest diameter and extend throughout the height of the screen wall 4 but leave a discharge gap 15 with respect to the screen wall. Adjacent each box 14 a further box 16 is formed by a wall 17 also secured to the oval drum 12, said box 16 at its end facing the screen wall 4 being provided with a scraper 18 also extending throughout the height of the screen wall. The scrapers 18 at their inner side are provided with guide blades 19 directed downwards.

A cylinder 21) is secured in the interior of the oval drum 12 and carries diametrically opposed sets of sprinklers 21, so that said latter are also rotating together with the hollow shaft 9. A gutter 22 for supplying the mass to be treated discharges into the upper end of the oval drum 12 and a pipe 23 for supplying washing or treating liquid opens into the cylinder 20.

The shaft 1, which is driven by a motor or by any other suitable means, hangs in a bearing block 24 sup ported in a rubber buffer 25. A gear box 26 is secured to the bearing block 24 so that said box isadapted to follow the oscillations, if any, of the shafts 1 and 9. On the shaft 1 a toothed wheel 27 is secured which through the intermediary of two

wheels

29, 30 transmits its motion to a toothed wheel 28 secured on the hollow shaft 9. The gear ratio between the toothed wheels 27 and 28 is such that the difference between the speeds of the shaft 1 and 9, which determines the duration of the treatment of the mass, is very small. Preferably the gear ratio of the toothed gearing is variable in order to vary the duration of the treatment at will.

For supplying compressed air or another compressed medium the lower part of shaft 1 is provided with a central bore 31 communicating by some radial hole 32, with a chamber 33 to which the boxes 16 are connected.

On the end of shaft .1 a stationary stuffing box 34 is mounted and said stuffing box is provided with a connection 35 for a pipe or flexible tube supplying a compressed medium.

In the bottom plate 13 discharge openings 36 are provided near the scrapers 18 and in the lower end of the outer wall of drum 2 openings 37 are provided. Said openings are located between guide plates 38.

The above described centrifugal machine operates as follows.

The mass to be treated is continuously delivered into the oval drum 12 by means of the gutter 22 and is uniformly distributed over the height of said drum under the centrifugal action. Due to the oval shape of the drum wall the entering mass is always guided towards the delivering boxes 14 in order to be deposited on the screen wall through gap 15. The thickness of the deposited layer depends on the width of gap 15. As the screen wall 4 moves relatively to the boxes 14 the mass is continuously deposited on the wall 4 and after a relative rotation of is removed from the wall 4 by the diametrically opposed scraper 18 and blown downwards by compressed air or another compressed medium discharged along the blades 19 so that the mass enters the lower part of drum 2 through the opening 36. The removed mass entering the lower part of drum 2 is thrown into the stationary outer drum 8 through the openings 37 and collected in the funnel 39. The separated liquid passes through the screen wall 4 and flows over the rim 6 in order to be collected in the gutter 7.

During the separation from the liquid of the mass deposited on the wall 4 said mass may be washed by water or treated by another liquid discharged by sprinklers 21. By the centrifugal action the liquid is discharged with such violence that an efiicient spraying of the liquid is secured.

Though in the illustrated. embodiment the compressed medium is supplied by the hollow scraper box 16, a platelike scraper may be used and a separate nozzle for the compressed medium may be mounted near the scraper.

Instead of vertically the centrifugal machine according to the invention may also be horizontally mounted.

What I claim is:

1. A continuously operating centrifugal machine, comthe side of the scraper facing the drum axis for dis charging amedium under pressure for blowing the solid particles detached from the screen wall by the scraper toward the discharge end of the drum.

2. A continuously operating centrifugal machine, comprising a screen drum having a screen wall and a discharge end, feed members in said drum extending substantially along the whole height of the screen wall of the drum, and a scraper device connected to said feed members and rotatable in the drum with an angular velocity slightly differing from that of the drum, said scraping device being shaped as a hollow body having a scraping edge and extending substantially along the whole height of the screen wall of the drum and being connected to a supply of a compressed medium, one of the walls of saidbody facing the drum axis and consisting of blades inclined towards the discharge end of the drum said blades being positioned so as to receive the compressed medium and direct the solid particles detached fromthe screen wall by the scraper toward the discharge end of the drum.

3. A continuously operating centrifugal machine, comprising a screen drum having a screen wall and a discharge end, a hollow feed box in said drum extending substantially along the whole height of the screen wall of the drum, a drum of oval section for receiving the mass to be treated, said feed box being secured to said oval drum at the largest diameter thereof, and a scraper device connected to said feed box and rotatable in the screen drum with an angular velocity slightly differing from that of the drum, said scraping device being shaped as a hollow body having a scraping edge and extending substantially along the whole height of the screen wall of the drum and being connected to a supply of a compressed medium, one of the walls of said body facing the drum axis and consisting of blades inclined towards the discharge end of the drum said blades being posi tioned so as to receive the compressed medium and direct the solid particles detached from the screen wall by the scraper toward the discharge end of the drum.

References Cited in the file of this patent UNITED STATES PATENTS 568,821 Waring et al. Oct. 6, 1896 1,253,428 Salcines Jan. 15, 1918 1,572,420 Birchall Feb. 9, 1926 1,902,982 Abbott Mar. 28, 1933 2,056,886 Pecker Oct. 6, 1936 2,312,829 Bird et al Mar. 2, 1943 FOREIGN PATENTS 134,092 Germany Oct. 2, 1902 280,363 Great Britain Nov. 17, 1927 812,298 France Feb. 1, 1937