US2773599A

US2773599A - Screen cleaning device

Info

Publication number: US2773599A
Application number: US386710A
Authority: US
Inventors: Litus John; Charles D Smith
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1953-10-19
Filing date: 1953-10-19
Publication date: 1956-12-11
Anticipated expiration: 1973-12-11

Description

1956 J. LITUS ET AL 2,773,599

SCREEN CLEANING DEVICE Filed Oct. 19, 1953 /9 is l /8\ k 1|| HIIIHIH m INVENTSDR bkn ZILIS' ATTORNEY 2,773,599 Patented Dec. 11, 1956 United States Patent Office SCREEN CLEANING DEVICE John Litus, Carteret, N. J., and Charles D. Smith, Lawrence, Kans., assignors to Food Machinery and Chemical Corporation, New York, N. Y., a corporation of Delaware Application October 19, 1953, Serial No. 386,710

4 Claims. or. 209-386) device perform in an optimum manner.

similar contrivances mounted under the active screening Other methods have involved laying an ordiunsatisfactory and has the additional objection of contaminating the product with small particles of rubber or whatever material is used in the object laid upon the screen. A similar device constructed by mounting a chain of small circular brushes on a ring made of plastic tubing also failed to give satisfactory cleaning.

The invention will be best understood by reference to the accompanying drawings which, representing one embodiment of the device, are illustrative only and not intended to limit the scope of the invention:

Figure 1 is an elevation view, partly in cross section, showing the use of the cleaning device on a circular vibratory separator, of the type described in the above mentioned patent.

Figure 2 is a plan view, in cross section, taken on the line 2-2 of Figure 1.

Figure 3 is a perspective view of one of the cleaning devices.

In the drawings, the separator 10 is equipped with one or more cleaning devices comprising brushes 11 mounted on an upwardly bowed resilient supporting bar 12 which may be shaped to conform to the contour of the underside of the screen 13. Ordinarily, these separators contain a plurality of screens mounted above one another, and it is usually desirable to provide one of the cleaning devices of the instant invention for each screen in the separator.

The supporting bar 12 may be made of any metallic or nonmetallic material possessing the necessary strength, workability and resiliency. The cleaning brushes 11 may have either metallic or nonmetallic bristles, or less desirably may be made of some other resilient material such as felt, fiber or rubber, so long as it is capable of keeping the screen mesh open without damage to the wires of the screen. Brushes are preferred because the cleaning action appears to depend to a considerable extent on the penetration of the holes by the bristles. Metallic bristles are very effective in some uses.

The brushes or other cleaning media may be fastened in any conventional manner to the supporting bar 12. Obviously, the brush arrangement on the arms can be varied considerably or even omitted on one arm, using it as a counterweight. Also, more than two arms may be employed.

As shown in the drawings, the center hole 14 of the supporting bar 12 fits loosely around the central retaining bolt or binding post 15, merely resting on the top of the spacing washers 16- atop the receiving tray 17 of the screen units. A washer on the binding post 15 is secured against the top center of the screens 13. The spacing washers 16, or any equivalent means, and the washer and nut on the binding post 15 are used as adjusting means to control the spacing between the cleaning medium and the under surface of the screen.- Thus, the supporting bar pivots freely about the retaining belt or center post 15.

It is important that the brushes or other cleaning media 11 fit the underside of the screen 13 closely enough so that the motion of the screen imparts an equivalent rotary motion to the device, but not so closely that this motion is hindered. This adjustment is the most critical point of operation, and must be done carefully to make the It is also very desirable that the brushes contact the underside of the screen over substantially the entire length of the arm, in order to obtain thorough cleaning action.

The manner of obtaining the circular vibratory motion referred to in the foregoing paragraph is exemplified in the above-mentioned patent, and is derived from the particular nature of the driving means there disclosed. Briefly, thesedriving means comprise the motor 18, a fixed eccentric 19, and an adjustable eccentric 20, all rigidly connected to the screen units. That subject is no part of the instant invention, but the operation of the cleaning device disclosed and claimed herein is based'on and limited to the type of motion as found in such circular vibratory separators. I

Thus, it should be noted that our cleaning device has no independent driving means, as is generally the case with many other prior art devices employing brushes for cleaning sieve screens. The motion of the screens imparts an equivalent motion to the brushes, which results in both horizontal and vertical, i. e. wave-like, movement, and a tapping of the underside of the screen repeatedly during a single revolution of the arms. The screen does not itself revolve. Thus, the cleaning media not only rotates under the screens, but the repeated tapping throughout the rotation movement is an important feature which is completely lacking in prior art devices. It appears that this tapping plays an important role in the unexpected efliciency of our cleaning device.

With this description in mind, the various dimensions of the brushes and supports may readily be worked out so as to fully realize the benefits of this invention. The use of this device gives improved cleaning of the screen, a saving in labor and maintenance cost which would otherwise be involved due to frequent disassembly for manual cleaning, keeping the separator on stream for a greater proportion of the time, yielding a product of more consistent quality, and increasing the screening capacity. As an example, the separator screens in one screening operation consistently blinded within thirty minutes so as to render the screen inoperative. After installation of the cleaning device of the instant invention, the screens were found to remain open for an entire eight hour shift. In other screening operations, the screens have remained open indefinitely.

It will be obvious to those skilled in the art that the foregoing description and drawings suggest equivalent and alternative features of construction of this novel cleaning device. For example, the cleaning media may be varied to utilize round brushes mounted so as to be free to rotate, or mounting the brushes on soft springs 3, 7 or some resilient material to improve contactwithflthe screen. It is intended that all such equivalent embodiments should fall within the'scope of the appended claims.

Thatwhich is claimedasnewis:

l. A screent cleaning device adapted for use between the screen and tray of a circular vibratory separator having a horizontal rotarycomponent of 'movementl and a vertical-vibratory component of movement, comprising: oppositely, radially extending upwardly bowed resilient arms loosely pivoted at'the center: of and below the screen and above the tray, abouta center post, and extending between the screen and tray said arms being spaced from: the tray atrall points, a cleaning medium positionedr upon the-upper surface ofat least one of said armsadapted to engage theund'erside of :said screen substantially'throughout the'length of said arm; and spacing means on said centerpost and bearing on the top of. said screen adapted to regulate the spacing between said cleaning-medium and thevunderside ofsaidscreen; whereby the circular vibratory motion ofthe screen is imparted tothe supporting arm and the-cleaning-medium, resulting in a wave-like motion and intermittent tapping and brushing ofthe underside of said screenrduring the revolutions of the arms about the center post, 4 substantially as described.

- 2. The device of claim 1, wherein the cleaning medium is a brush.

3. In a circulatory vibratory. separator. of the type described, having a horizontal rotary component of movement and a vertical vibratory component of movement, a screen, a receiving tray undersaidscreen,rmeans connecting said screen and said tray at the center thereof comprising a binding post extending through the tray and the screen and a nut on the binding post, and a washer bearing on the top of the screen whereby the spacing between the center of the screen and tray maybe adjusted, a space between the screen and the tray, a brush member mounted on an upwardly bowedresilientr-arm loosely pivoted on said binding post in the space between the screen and the tray and spaced at all pointsmfromcthe tray, bristles on said brush projecting through said screen whereby circulatory vibratory motion imparted to said screen will cause rotation of said brush around said binding post as a center, and means to impart circulatory vibratory motion to said screenand tray.

4. In a circulatory vibratory separator of the type described, having'a' horizontal rotary component of move ment anda vertical vibratory component of movement, a' plurality of screens spaced vertically of the axisof said separator, a; receiving tray under each screen; .means' to discharge a material from each tray, means' connecting eachscreen with the tray below at the center thereof comprising a binding post extending through the tray and the screen and a nut on..the'.;binding post, whereby each screen may be adjustably pulled toward the tray below, a space around said binding post between each screen and the tray below, anupwardly'bowed, resilientwarm member carrying a brush loosely pivoted on said binding postinlthespace betweenaeach screen andthe tray below andhspaced at all points from said tray, bristles on-said brush-projectingupwardly against each screen, and means to-impart circulatory vibratory'motion to said screens and trays whereby saidarms and brushesxare caused to rotate under said screen, solely ,by the circulatory vibratory motion imparted-t0 said screens and the contact between said'screens and said brushes.

References Cited in thefile of this patent UNITED STATES PATENTS 476,532 "Edison ."June 7, 1892 1,298,558 Peter Mar. 25, 1919 2,284,671 Meinzer June 2, 1942 FOREIGN PATENTS 1 441477 GIeat Britain June 17, 1920 648,887 Great Britain Oct. 28, 1942 550,661 Great- Britain Jan. 19,1943

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