US2913169A - Centrifuge drive arrangement - Google Patents

Description

Nov. 17, 1959 w. WILSMANN CENTRIFUGE DRIVE ARRANGEMENT 2 Sheets-Sheet 1 Filed Sept. 17, 1956 III FIGJ

INVENTOR. WIL HELM WILSMM MT DRI/EYQ Nov. 17; 1959" FilOd Supt. 17, 1956 w. WILSMIANN 2,913,169

| v IO WILHELM WILSMANN ATTORNEYS INVENI'OR United States Patent CENTRIFUGE DRIVE ARRANGEMENT Wilhelm Wilsmann, Oelde, Westphalia, Germany, as-

siguor to Westfalia Separator A.G., Oelde, Westphalia, Germany, a corporation of Germany Application September 17, 1956, Serial No. 610,277

Claims priority, application Germany September 19,1955

Claims. (Cl. 233-23) This invention relates to animprovedcentrifuge drive arrangement. The invention more particularly relates to an improved drive arrangement for centrifuges provided with a vertical drive spindle which is directly driven by an electric motor.

In centrifuges, such as centrifugal separators, which are directly driven by an electric motor, the centrifuge generally has a vertical drive spindle rotatably mounted by means of an upper and lower bearing in a centrifuge frame. The centrifugal bowl is mounted above on the Vertical drive spindle, and the :electric drive motor is mounted below the drive spindle in axial alignment therewith and directly connected to the drive spindle, as, for example, by means of an elastic coupling. .The lower bearing, which is generally developed as a selfaligning swing bearing, supports the Weight of the centrifugal drum and the spindle in an axial direction, while the upper bearing is developed with radial elasticity in order to be able to take up the radial oscillations of the spindle during operation. The bearings are generally grease-lubricated bearings, asfor example,.ball or roller bearings which are packed with grease to assure smooth and easy operation.

In such an arrangement, since the bearings and th drive motor are arranged below the centrifugal drum or bowl, a danger exists that liquid will penetrate into the bearing and into the motor winding if the bowl overflows. This may occur, for example, if the bowl is fully filled before it has reached the full speed of rotation. Thus, for example, when the centrifuges named for the separation of cream it is customary to add skimmed milk before the centrifuge is stopped in order to displace the cream out of the bowl. In this connection, the bowl often'overflows with the liquid entering the centrifuge frame and penetrating the bearings and the motor. Also, when cleaning the centrifuge, the washing liquid may penetrate thebearings and motor windings. The penetration of the moisture .into the bearings tends to reducethelubricating effect ,of .the grease, and, in instances where the centrifuge stands for a long time without operation, it also tends to promote rust formation. In this waythe satisfactory operation of the centrifuge is greatly impaired and the life decreased. The higher frictional resistances caused by the decrease in the lubrication results in a greater temperature rise and a greater wear of the bearings. The penetration of the moisture into the electric motor, besides causing wear of the bearings of this motor, leads to a reduction of the insulation resistance of the winding and thus to a decrease in the life of the motor and often short circuits it.

One object of this invention is a bearing and motor arrangement for a centrifuge of the above-mentioned type which avoids the above-mentioned disadvantages. This, and still further objects will become apparent from the following description read in conjunction with the drawing, which shows a vertical section of an embodiof theupper chamber 19*and an outlet drain 25.1eads 'through these drain outlets.

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vertical drive spindle rotatably mounted by means of an' upper and lower grease-lubricated bearing in a centrifuge frame and provided with an electric motor vertically mounted below the drive spindle and directly connected thereto for drive actuation. I

In accordance with the invention, the centrifuge frame defines an upper and a,lower chamber-surroundinggthe upper and lower bearing, respectively. These chambers define liquid-retaining troughsat'their bottom portion having outletdrain means. The upper-bearing, and preferably both the upper and lower-bearings, are protected by protective sleeves which surround the same and-preferably terminate with,th eir upper ends closely adjacent the spindle. 1 a

Fig. 1 is a vertical axial section of the structure embodying this.invention. Fig. 2 is a further showing of the same showing the feature of the lever bearing protection from moisture.

Referring'to. the embodiment shown in the drawing, the drive shaft 1 of theelectric drive motor 2. is connected by, the flexible coupling. 3 withthe vertical drive spindle 4'whichcarries thecentrifugal bowl 5. As the construction of thebowl or drum. 5 is conventional and the spindle 4 by a counter-balanced opposefd'off-set' Such coupling arrangement is conventionaLfand any other knownor conventional arrangement may be used which will'take up the shocks of starting and stopping and during operation, and which will allow a limited flexing of'the spindle with respect to the motor during operation. v

The vertical spindle 4 .is supported in'the centrifuge frame l6fby means-of an upper grease-lubricated ball bearing 16 and alower grease-lubricated ball bearing 7.

The cen'trifugelfi defines an upper chamber-19 and a lower chamber {20, which have the horizontally extending partitions 17 and '18, respectively, which form liquidretaining troughs at the bottom .of the chambers and which'support the upper and lower bearings,frespectively. Anoutlet drain pipe 22 for liquidleads from the trough from the trough of thelower chamber 20, so tha tfany liquid falling in thesetroughs will run out of thesanae The'frame 16 additionallyi'defines an annular}space 26 below the lower bearing '7. and the lower chamber .20.

An outlet drain pipe27 'leads'from this annular space to the outside, extending through thedrain 25.

The lower ball bearing 7 is formed as a self-aligning swing bearing which will allow a limited pivoting of the spindle 4 with this bearing acting as a point of pivot. Surrounding thebearing 7 is aprotective sleeve 12, in which the outer race of the bearing is mounted. Thesleeve 12 is bell-shaped and mounted in thepartition 18. The upper portion of theprotective sleeve 12 closely surrounds the spindle and a labyrinth seal cap 10 is mounted on the spindle, sealing the upper end of theprotective sleeve 12 from moisture. The bottom of theprotective sleeve 12 is sealed by means of abottom cover plate 13, which is held in place by the expandedsnap ring 15, which fits into an appropriate groove in the inner surface of the sleeve.

Theupper bearing 6 has its outer race mounted in a protective sleeve '8, which is bell-shaped and which closely surrounds the spindle at its upper end and which is provided with a-coverplate 11 atits-lower-endmaintaincd in place by an expandedsnap ring 14. Theprotective sleeve 8 is mounted in a secondcylindrical sleeve 24, which is secured by means of its upper lip to the partition 17. Thesecond sleeve 24 is of smaller diameter than the opening through the partition 17 and is resiliently maintained in place by springs which allow resilient lateral movement. Alabyrinthcap seal 9 surrounds the spindle 4, sealing the upper end of theprotective sleeve 8. Thecap 9 also co-operates with theflange 23 to form a double labyrinth seal. .Theflange 23 is screwed to the partition 17 and holds thesecond sleeve 24 secure from axial movement. The second bearingsleeve 24 is provided with openings in the side wall thereof, so that moisture penetrating the labyrinth seal caused by the cap. 9 may run over the outer surface of theprotective sleeve 8 through these openings into thelower chamber 20.

The resilient mounting of the upper bearing in combination with the swing arrangement of the lower bearings allows the limited necessary. swing'of the spindle 4 during operation. v

It is also, possible to eliminate the labyrinth cap 10 and to extend theprotective sleeve 12 into the secondcylindrical sleeve 24. i a

In operation, theelectric motor 2 drives the vertical drive spindle 4 in the conventional manner, which causes rotation of the centrifugal bowl ordrum 5. Any liquid over-flowing from the bowl will enter the chamber .19, collect'in the trough at the lower portion of this chamber, and will be discharged through thedischarge pipe 22. Theprotective sleeve 8 and thelabyrinth cap seal 9 protect thebearing 6 from this liquid. If any moist air or liquid passes through the upper labyrinth seal formed bylabryrinth cap 9, the same will merely pass down over the outer surface of theprotective sleeve 8 through the opening in thesecond sleeve 24 and into thelower cham ber 20, where the same will collect in the lower trough anddrain oif through thedrain opening 25. This also holds true for moisture which may penetrate the upper labyrinth seal and condense in the lower chamber.

The lower bearing is protected from this moisture by means of itsprotective sleeve 12 and cap 10 Should, however, any moisture enter through thebottom bearing 7, this moisture will accumulate in theannular space 26 and be discharged through thesmall pipes 27. The portion where the drive shaft and coupling extend through the annular chamber is protected by a labyrinth cap similar to that used in connection with the bearing.

The bearings and the motor are thus positively protectedj from the deleteriouseifects of the liquid which overflows from the bowl and the life of the bearing shaft, and the motor is greatly increased.

' While the invention has been described in detail with reference to the specific embodiments shown, various changes and modifications will become apparent to the skilled artisan which fall within the spirit of the invention and scope of the appended claims. A i

1. In a centrifuge having a vertical drive spindle rotatably mounted by means of an upper and lower hearing in a centrifuge frame and having an electric drive motor vertically mounted below said drive spindle directly connected thereto for drive actuation, the improvement which comprises said centrifuge frame defining a horizontally extending partition dividing said centrifuge frame into an upper and lower chamber surrounding said upper and lower bearings respectively, said chambers defining liquid retaining troughs at their bottom portions having outlet drains leading out of said centrifuge frame, a protective sleeve surrounding said upper bearing and a labyrinth seal surrounding said spindle and sealing the upper portion of said sleeve, said labyrinth seal being mounted to participate in the radial oscillations of the spindle during operation.

2. Improvement according to claim 1 in which said Y partition defines said trough for said upper chamber and in which said upper bearing is mounted in said partition.

3. Improvement according to claim 1, including a passage communicating said upper and lower chamber for liquid passing through said labyrinth seal over said sleeve.

4. Improvement according to claim 3, in which said protective sleeve is a bell shaped sleeve .with its upper end closely surrounding said spindle and including a cover sealing the bottom of said sleeve.

5. Improvement according to claim 4, in which said sleeve is positioned in a second cylindrical sleeve mounted in said partition and in which said passage is defined through said second sleeve.

6. Improvement according toclaim 5, including a protective sleeve surrounding said lower bearings.

7. Improvement according toclaim 6, including a labyrinth seal surrounding said spindle and sealing the upper portion of said protective sleeve surrounding said lower bearing.

8. Improvement according to claim 1, including an annular space defined by said centrifuge frame positioned below said lower bearing and chamber, and an outlet drain leading from said annular space. 1

9. Improvement according to claim 1, in which said centrifuge frame defines a horizontally extending partition defining said'trough for said upper chamber and separating said chambers, and in which said protective sleeve is mounted in a second cylindrical sleeve in said partition, and'including a second protective sleeve sur- UNITED STATES PATENTS 984,242 Sanford et al Feb. 14, 1911 1,006,174 Anker-Holth Oct. 17, 1911 1,598,393" Robertson Aug. 31, 1926 1,888,475 Schmitz Nov. 22, 1932 2,587,418

1 Wahlberg Feb. 26, 1952

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