US2192589A - Discharge of the centrifugal substance from a centrifugal drum - Google Patents

Description

c. SCHMITZ Marchs, 1940.

DISCH ARGE OF THE CENTRIFUGAL SUBSTANCE FROM A'CENTRIFUGAL DRUM Original Filed April 7, 1934 ill/III! v Patented Mar. 5, 1940 UNITED STATES PATENT OFFlCE DISCHARGE OF THE CENTRIFUGAL SUB- STANCE FROM"A CENTRIFUGAL DRUM Carl Schmitz, Oelde, Germany Original application April 7, 1934, Serial-No.

719,543. Divided and this application Febru ary 7, 1935, Serial No. 5,47

'0ct0ber 25, 1933 1 Claim.

the lossesthe treatment of the milk in the next following apparatus is often accompanied by difliculties.

- It is an object of the invention to provide improved means for preventing the formation of froth in a machine ofthe kind referred to.

To this end, in combination-with a bowl or 16 drum arranged to rotate about a vertical axis, a stationary tube is arranged with its axis in the axis of rotation of the drum, a tubular stripper is connected to the tube at its upper end, a hollow driving spindle is connected to the drum at,

20 its upper end, a hollow driving spindle is connected to the centre of the bowl with its upper end and surrounds the stripper tube in co-axial relation, and means are provided for producing back pressure in the stationary stripper tube. Without the back-pressure producing means, the stripper would remove so much of the surface layer on the inner side of the hollow paraboloid formed by the liquid under centrifugal action, that the ends of the stripper would be tangent to the side, and the air would have free access. Under the back pressure, however, the liquid in the stripper tube is backed up and the consequence is that a surface layer of liquid is presented to the stripper whose depth is such that access of air to the stripper is prevented, and so no froth can form. The hydraulic seal established by the back-pressure producing means is preferable to mechanical packing means as heretofore provided, for obvious reasons.

An embodiment of the invention is illustrated by way of example in the accompanying drawing in which Fig. 1 shows a centrifugal separator in vertical section.

Fig. 2 is a horizontal section through the stripper.

A stationary tube 3 with a stripper 4 at its upper end is surrounded in co-axial relation by the hollow driving spindle of a centrifugal drum 5o 2. The tube 3 and the spindle l-make .up an annular space 8. A bearing l5 for a journal at the upper end of the stripper tube 3 is formed in a horizontal partition I6 arranged above, and

, ball bearings in the frame of the machine.

In Germany serted centrally in the bottom of the drum or bowl, and the spindle is supported by two radical The drum, or bowl, is a cylinderwith a tapered top, and I3 are cream holes at the upper end of the top. The stripper 4 extends into a stripping chamber 6 separated from the centrifuging chamber 5 by the partition l6. Arranged at the lower end of the hollow driving spindle l is a stuiling'box 9 or some other, for example liquid seal for closing the lower end of the space 8. A horizontal discharge pipe II, with a cock l2, or other suitable means for varying its free sectional area, is connected to the lower end of the spindle l below the seal 9, and a pressure gauge I4 is connected to the discharge pipe.

Vanes l whose inner ends extend into the vicinity of the strippers ends, arearranged in the chamberli between the partition l6 and the bottom of the drum or bowl 2, and ports! near the inner wall of the drum or bowl 2 connect its interior to the chamber.

When the spindle l is rotated, the centrifuged liquid forms about the stripper 4 a hollow body of revolution. It will be understood that, since the liquid has free access to the chamber 6 through the ports I the hollow body is continuous, i. e., not interrupted by the partition I6 I and the tapered side wallof the chamber 6. Owing to the considerable height of the body, the portion which is in the chamber 6 may be considered practicallyas a hollow cylinder, the departure from a paraboloid being negligible. The ends of the stripper 4 enter into the cylinder and remove a certain percentage of the rotating liquid. If this liquid were allowed to flow freely from the lower end of the stationary tube IS, a condition would soon be established in which the ends of the stripper 4 would be practically tangent to the hollow cylinder of liquid in the chamber 6. In order to prevent this, and to keep the ends of the stripper immersed in the body of liquid to a depth sufficient for the permanent exclusion of air, back pressure is established in the tube 3 by means of the cock I! in the discharge pipe I I, and the back pressure is indicated at the gauge l4. Only a short depth of penetration into the hollow liquid cylinder in the chamber 6 is necessary for a froth-free delivery with low back pressure in the tube ll. inside diameter of this cylinder is considerably smaller than the inside diameter of the drum and the diameter of the stripping circle is correspondingly small. This results in a slightffrictional resistance at the outer ends of the stripper The 4 and enables the drum to rotate at the high speed which is necessary for skimming and which could not be economically attained with a greater depth of penetration.

As compared with known separators the advantage is also derived that the cream discharge zone at I3 may be of small diameter so that the cream is discharged at low speed.

The invention may also be employed for centrifuged substances which are only to be cleansed. The admission and the discharge of the separated portion of the liquid are efiected througli tightly closed connections with the drum. A plurality of devices according to the invention may also be employed in one drum.

As with the closed admission the pressure for forcing the centrifuged substance through the apparatus is lacking or considerably reduced, the packing on the feed pipe is relieved.

I claim:

A machine for centrifuging liquids having a the liquid, a stationary tube arranged concen-' trically with the drum axis and communicating with said stripper, said tube serving for leading ofi the liquid from said stripper, and a throttle element on said tube accessible from the outer side and adapted to influence the leading oii of the liquid and consequently the liquid level in the stripper chamber for preserving a liquid seal between said stripper and said stripper chamber. CARL SCHMITZ.

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