US3309015A

US3309015A - Centrifuges

Info

Publication number: US3309015A
Application number: US383433A
Authority: US
Inventors: Jung Erland Viktor; Monteus Sven Hilding
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-07-31
Filing date: 1964-07-17
Publication date: 1967-03-14
Anticipated expiration: 1984-03-14
Also published as: DK119550B; NL6408705A; BE651072A; ES302609A1; GB1030149A; DE1209506B

Description

March 14, 1967 E. v. JUNG ETAL CENTRIFUGES 2 Sheets-Sheet 1 Filed July 17, 1964 E. V. JUNG ETAL arch 14, 1967 CENTRIFUGES 2 Sheets-Sheet 2 Filed July 17, 1964 United States Patent O 3 claims. icl. 233-10) The invention relates to discontinuou'sly operating centrifuges and has for its object to facilitate removal of the centrifuged pulp from the centrifuge drum rotating about a vertical spindle. For this purpose the centrifuge is provided with a scraper for separating the pulp after this has been deposited, by the centrifugal action, on the inside of the drum in the form of a hollow cylinder, the pulp after separation escaping through outlet openings in the bottom of the drum. The scraper is operated yby means of a rotatably and/or displaceably mounted rod to the lower end of which the scraper is secured.

In centrifuging pulp of a baking nature centrifug'es of the kind stated above have the disadvantage that the bottom openings are rapidly clogged -fby the excavated pulp, for which reason the drum must ybe cleaned manually with accompanying shut-downs. It has been proposed previously to obviate these diiculties by subjecting the separated pulp, during the whole or a part of the excavating process, to the action of compressed air, the air and the pulp then forming a suspension which is discharged very rapidly through the bottom openings. Devices of this kind are lknown wherein the compressed air is caused to flow out through air nozzles mounted on the scraper or on a member associated With the scraper and connected through a ilexible hose to a compressed air conduit located outside the drum. However, this device has several disadvantages. Among -other things the flexible hose is exposed to hard wear. Furthermore, this device renders it diflicult to cover in or encase adequately the centrifuge drum which is desirable, i.e. for protecting the centrifuged pulp from being contaminated. These disadvantages yare obviated according to the present invention by the compressed lair being supplied to the air nozzles through a longitudinal passage provided inside the operating rod. Thanks to this arrangement the centrifuge drum together with the scraper secured to the lower end of tne operating rod may be enclosed in a casing completely covering the centrifuge at the top and on the sides, and the necessary sealing may be provided about the rod in its passage opening in the casing.

The invention will `be described in greater detail with reference to the accompanying drawings. FIG. 1 is a vertical view, partly in section, of a centrifuge provided with a device for supplying compressed air to the interior of the drum in accordance with the invention.` FIG. 2 shows, on a larger scale, the tube structure wherein the operating rod is rotatably and displaceably mounted, and also a slide valve device for supplying compressed air to the air passage provided centrally in the operating rod.

The centrifuge drum 1 is mounted with its spindle 2 and driving motor 3 on a frame consisting substantially of a girder system 5 arranged on legs 4. The drum 1 has a cover 6 and a bottom 7 which latter has openings 8 provided centrally therein. These openings 8 form outl-ets for the pulp separated by means of the scraper, which pulp has deposited during the centrifuging process on the inside of the drum in the form of a hollow cylinder 9. The loperating rod 10 is rotatably and displaceably mounted in known manner in a tube 11 which is secured at its top to the girder 5 and at its bottom to the upper end wall 12 of a cylindrical casing 13 enclosing the centrifuge drum and the excavating device, the tube being ice secured to said end wall by means of a socket 14 encircling the lower end of the pipe 11. The excavating device consists of a scraper 15 which is rigidly secured to the lower end of the rod 10 by means of an arm 16, said rod passing through the end wall 12. The upper end 17 of the operating rod 10 is threaded and adapted to be displaced axially `by means of a nut which is screwed on to said part 17 and can be caused to rotate by means of a motor 18. During its movement the operating rod is guided by means of a pin and groove connection comprising a pin 19 mounted on the rod and a groove 20 provided 'in the tube 11, 4said groove substantially extending axially but being bent or diverted laterally -at its upper end. In displacing the operating rod downwards from the position shown in FIG. l, the rod will first be rotated at the same time as it is moved downwardly, in so doing the scraper 15 is swung in under the cover 6 to the position indicated by chain-dotted lines, the scraper thus cutting its way into the pulp cylinder on the inside of the drum 1. Upon further movement downwards of the operating rod the pulp cylinder is excavated axially until the scraper arrives into its lowermost position when the whole pulp cylinder has been removed.

In order to facilitate removing of the pulp from, the dmm means ar-e provided for the supply of compressed air to a nozzle 21 disposed at the lower end of the arm 16 carrying the scraper and connected through a pipe 22 to a passage 23 provided centrally in the operating rod, which passage may Ibe connected in turn to a compressed air conduit 24 'by means of a valving device controlled :by the rod. As will be best seen from FIG. 2, the compressed air conduit 24 is connected to a hole 25 in the lower part 26 of the tube enclosing the operating rod, said hole communicating with a pressure chamber 27 arranged on the inside of the tube part 26. This pressure chamber is sealed against the rod and the tube part 26 by two Isealing rings 28. By means of a cylindrical sleeve 29 inserted into the chamber the sealing rings .are kept apart and pressed against the edges of the end portions 30 of the sleeve, in which portions holes 31 are provided. The central air passage 23 is adapted to communicate with said pressure chamber 27 through a bore 32 extending radially from the upper end of the passage.

During the longitudinal movement of the operating rod it functions as a slide valve to control the connection between the compressed air conduit 24 and the central passage 23 in such manner as to open `and close the air inlet in certain axial positions of the scraper, which are determined by the relative position of the pressure chamber 27 and the 'bore 32 and by the axial extent of the pressure chamber. The arrangement is suitably such that compressed air is supplied to the nozzle 21 when the scraper 1S moves through the lower part of the drum. The air nozzle is arranged in such a way that the pulp separated #by the scraper is affected by the outowing air and is caused to escape through the outlet openings 8 in the ybottom of the drum.

What is claimed is:

1. In a centrifuge, in combination, a rotatable centrifuge drum, a scraper for excavating pulp deposited on the inside of the drum during operation, means causing said scraper t-o carry out a radial and an axial excav-ating movement in said drum including a rotatably driven and axially slidable elongated rod carrying said scraper, said drum having outlet openings in the bottom thereof, a compressed air nozzle arranged on the scraper, said rod having a longitudinal passage provided interiorly ofy said rod and communicating with said nozzle, means for supplying compressed air to the nozzle to cause pulp excavated by said scraper to be discharged through said outlet openings, the last-mentioned means comprising a stationary compressed air 4supply conduit, and means defining a slide valve comprising said rod operated -by the said axial movement of the rod to control passage of air between said stationary air supply conduit and said longitudinal passage to apply compressed air to the nozzle in predetermined axial positions of the scraper.

2. In a centrifuge according to claim 1, in which said slide valve comprises a tubular member circumferentially of said rod extending axially thereof at least a limited axial extent thereof, said tubular member defining a pressure chamber circumferentially of said rod, communicating with said stationary conduit, said rod comprising a second passage communicating between the exterior of said rod and said longitudinal passage, whereby when said rod moves to a given axial position in which said second passage is in communication with said chamber compressed airis applied to saidk nozzle.

3. vIn a centrifuge according to claim 2, in which said chamber is disposed in a position in which said nozzle is 4 rendered effective at axial positions during which said scraper is moving axially through a lower part of said drum thereby to'blow out excavated pulp out of said openings.

References Cited by the Examiner UNITED STATES PATENTS 1,048,905 12/1912 Sperry 210-377 X 1,704,053 3/1929 Miller 285-190 X 2,056,885 10/1936 Pecker 210--375 2,590,787' 3/1952 Nickles 285-190 X 2,953,250 9/1960 lung et al. 233410 X FOREIGN PATENTS 250,155 2/1963 Australia.

M. CARY NELSON, Primary Examiner.

HENRY T. KLINKSIEK, Examiner.

Claims

1. IN A CENTRIFUGE, IN COMBINATION, A ROTATABLE CENTRIFUGE DRUM, A SCRAPER FOR EXCAVATING PULP DEPOSITED ON THE INSIDE OF THE DRUM DURING OPERATION, MEANS CAUSING SAID SCRAPER TO CARRY OUT A RADIAL AND AN AXIAL EXCAVATING MOVEMENT IN SAID DRUM INCLUDING A ROTATABLY DRIVEN AND AXIALLY SLIDABLE ELONGATED ROD CARRYING SAID SCRAPER, SAID DRUM HAVING OUTLET OPENINGS IN THE BOTTOM THEREOF, A COMPRESSED AIR NOZZLE ARRANGED ON THE SCRAPER, SAID ROD HAVING A LONGITUDINAL PASSAGE PROVIDED INTERIORLY OF SAID ROD AND COMMUNICATING WITH SAID NOZZLE, MEANS FOR SUPPLYING COMPRESSED AIR TO THE NOZZLE TO CAUSE PULP EXCAVATED BY SAID SCRAPER TO BE DISCHARGED THROUGH SAID OUTLET OPENINGS, THE LAST-MENTIONED MEANS COMPRISING A STATIONARY COMPRESSED AIR SUPPLY CONDUIT, AND MEANS DEFINING A SLIDE VALVE COMPRISING SAID ROD OPERATED BY SAID AXIAL MOVEMENT OF THE ROD TO CONTROL PASSAGE OF AIR BETWEEN SAID STATIONARY AIR SUPPLY CONDUIT AND SAID LONGITUDINAL PASSAGE TO APPLY COMPRESSED AIR TO THE NOZZLE IN PREDETERMINED AXIAL POSITIONS OF THE SCRAPER.