US3635349A

US3635349A - Power-operated extensible skimming blade

Info

Publication number: US3635349A
Application number: US81273A
Authority: US
Inventors: Gordon E Weiss; John B Rank; Gilbert W Quast
Original assignee: Rex Chainbelt Inc
Current assignee: Siemens Water Technologies Holding Corp
Priority date: 1970-10-16
Filing date: 1970-10-16
Publication date: 1972-01-18
Anticipated expiration: 1989-01-18

Abstract

A reciprocating bridge with scraper and skimmer blades operates in a tank requiring skimming to the uneven sidewalls of the tank. Each end of the scraper is provided with a pivoted blade which is retracted when the blade is elevated. The blade is extended by a spring when the blade is lowered and the spring holds the blade against the sidewall of the tank at all times but with no unrequired force.

Description

lJnited States Patent Weiss et a1.

Jan. 18, 1972 POWER-OPERATED EXTENSIBLE SKIMMING BLADE Gordon E. Weiss, Butler; John B. Rank, Milwaukee; Gilbert W. Quast, Brookfield, all of Wis.

Assignee: Rex Chainbelt, Inc., Milwaukee, Wis.

Filed: Oct. 16, 1970 Appl.N0.: 81,273

inventors:

[1.8. CI ..2l0/527 int. Cl ..B0ld 21/04 Field of Search ..2l0/525, 527

[56] References Cited UNITED STATES PATENTS 1,911,008 5/1933 Withington ..2l0/527 X Primary Examiner.lim L. DeCesare Attorney-Ernst W. Schultz and Joseph J. .lochman, Jr.

[57] ABSTRACT A reciprocating bridge with scraper and skimmer blades operates in a tank requiring skimming to the uneven sidewalls of the tank. Each end of the scraper is provided with a pivoted blade which is retracted when the blade is elevated. The blade is extended by a spring when the blade is lowered and the spring holds the blade against the sidewall of the tank at all times but with no unrequired force.

4 Claims, 3 Drawing Figures 1 rowan-creamer) sxrsssmrn SKIMMING sums BACKGROUND or THE INVENTION Skimmer blades which are carried byfland between chains have been fitted at their'ends with-wipers vwhich'rub the skimming blade to' scrape the sidewalls of the tank. Each assembly is-identical except that theya're rightand left handed and the same reference numbers are applied to the same parts.

sidewalls of the separation'tank. Such wipers wear outrapidly 7 and require regular maintenance..They require only some retraction because they move with the chains in the same relative direction at all times. A reciprocating bridge carrying a single skimming blade is most often used withlarge rectanguwhich are only roughly, or approximately, straight.

Such a bridge lifts the skimming blade at the end of the skimming run and for the return run may have toclear some projections such as some structural parts of the tank.

SUMMARY OF THE INVENTION Theextension at each end of a skimming bla'deis pivoted on a vertical axis aheadof the extremity of the .blade. Apart of resilient means to hold them outwardly and do not require lar tanks of concrete construction very often having: sidewalls the blade adjoins a cylindrical part of theextension to form a seal. A spring andcable are .connected to the extension and the carriage so that the raising and loweringof the'skimmer blade respectively retracts and extends the'scraper. blades.

. BRIEF DESCRIPTION OF THE-DRAWING FIG. 1 shows in side elevation and partially in section, a

travelling bridges and the lowersn'ucture whichcarries a 3 scraper blade in the it raised position. The end view .of the skimming blade in the lower position is shown and a section of "The upper and lower brackets dl'a'nd 42 are secured to the upper and lower edges of the blade 31 and extend forwardly thereof tocarry the vertical shaft 43. Scraper blade 40 extends from the member 44 mounted on shaft 43 between brackets 41." Member 44 and the blade 40 together fonn acylindrical surface which maintains a nominal clearance with the block 45 fixed to the end of blade 31. This clearance amounts to seal in that the oil being pushed by the skimmer blade cannot pass therethrough because of its'relatively high viscosity.

The operating levers fixed to the upper end of shaft 43 include the forward spring lever 46 which is connected by the "spring 47 to the blade 31. A series of holes in lever 46 allows for the selective adjustment of the spring.

n The other operating lever 49 fixed to the upper end of shah 43 extends over skimming blade 31 and is operated by the cable 51. Cable 51 operates over the pulley 52 carried by blade 31 and has its ends connected to lever 49 and to brace 36 at a location below shaft 34 and bearing 35.

' The arrangement of the cable is'such that when skimming blade 31 is in its upper. position, the cable is in tension and its length is such that spring 47 is expanded and the member 44 is f rotated away from theadjacent'iwallfand a substantial ously referred to, skimming blade 31 is lowered and the effecthe blade is shown also in the upper position. This: additional upper position is taken approximately on Section 1-1 of FIG.

I FIG. 2 is a plan-viewof the endof the skimming vbladeand includes part of the supporting structure.

tive length of cable 51 is increased so that spring 47 is operative to turn shaft 43 and move scraperblade 40 to'engage the wall. This engagement occurs before blade 31 is fully lowered.

When the skimming blade is fully lowered, cable 51 is slackened so that some movement of'member 44 and blade 40 FIG. 3 is a'plan view of the other end of the'skimming blade in the elevated position.

DESCRIPTION OF THEPREFERREDZEMBODIMENT The bridge includes the frame 11 havingwheels at each end which roll on parallel rails fixed to and extend along the top of each side of the rectangularitank: The flangedwheels l2 and 13 supporting one end of the bridge and the one rail 15 fixed to the top of the wall 16 forming one side of the tank are shown in FIG. 1. Wheel 12 and the correspondingotherwheel at the other end of the bridge are driven by the 'moto'r 17 through the reduction gear unit 18andchain drive -19'which tumsshaft 20 on which thewheels are mounted. In the forward direction of travel which is to the left as shown, the sludge :scrap'er 21 is in the lower'position shown .in broken lines to move the settled material over the floor 22:0f the tank toward a coilectinghopper, not shown. Scraper=21 is 'pivotally carried at the lower end of thew'frame 23 extending downwardly from bridge 10 and is connected by rod 241to the control lever 25which also operates theskimmerblade 31.

Blade 31 extends between the sidewalls 32 and 16 -1of the tank, respectively shown in FIGS; 2 and 3-and is carriedaby the arms 33 to which the blade'isattached.

Arms 33 are fixed to shaft 34 whichis pivotally supported by spaced bearings including the bearing 35 carried by... brace 36. The lever 37 extending'from shaft 34 .is adjustablyconnected by link 38 with lever 25 so that when the sludge-scraper 21 is in the lower position, the skimming blade 31 is-supported above the water level of the tank.

As bridge 10 reaches one end of the tank, its travel reverses and the bridge then moves in the return, or' skimming direction. During such reversah power-operated 'means; not

is allowed.

:zThis movement, within limits, allows the scraper 44 to be :heldagainst the adjacent wall as thebridge 10 moves toward the otherend of the tank. As has been noted, the

walls

16 and 32 of the tank may be only approximately straight and the engagement of the two blades therewith is efiective over the entire length of the tank to keep the floating material or oil to be removed'from passing around the ends of blade 31.

As the bridge approaches the other end of the tank, the

floating material is pushed into a'trough not shown, from which it is discharged. The trough may be of any'suitable arrangement. The most common includes a'beach or ramp extending from'below the waterlevel to the edge of the trough v which isabove the water level.

' When the floating material has been pushed into such a ntrough, the bridge 10 stops and the sludge scraper 21 is 5.5: relowered and the skimming blade 31 is again elevated.

tive length of cable 51 and pulls lever 49 to retract the scraper -blade 40. The operation of the scraper blades 40 at both ends l The upward movement of the blade again reduces the effecof theskimming blade are or can be adjusted to be simultaneous by adjusting the lengths of the two cables.

We claim:

l. ln combination with a reciprocating carriage carrying a skimming blade in a lower position first to push material floating between the two parallel walls of a gravity separation tank shown, lifts sludge scraper 21 to its upperposition and'lowers the skimming blade 31by1rotating shaft According to the present invention, each 1 end of the skimming blade is provided with an assembly including an extensible scraper blade 40 which' forms an extension of the tank as the skimming blade moves in its lower position, and a linkage connecting the scraper blade .and the carriage to retract the blades as the skimming blade is elevated to provide a clearance between the scraper blades and the walls of the tank in the elevated, return position, said linkage being operable torelease the scraper blades as the skimming blade is relowered forskimming.

2. In combination with a skimming blade carried by the reciprocating bridge of a rectangular gravity separation tank, said bridge carrying said skimming blade in a lower position as the bridge travels in one direction and in an upper position above the water level of the tank during the return travel of the bridge; an extensible scraper blade carried by and at each end of the skimming blade and which extend toward the walls of the tank, springs having ends operatively connected to the skimming blade and to said two scraper blades and biasing the latter to engage and follow the walls of the tank, and linkage means connecting said scraper blades and the bridge at locations such that as the skimming blade is raised and approaches its upper position the linkage operating against the springs retracts the scraper blades from the walls of the tank and as the skimming blade is lowered the effective length of the linkage increases and first allows the springs to extend the scraper blades to engage the walls of the tank and thereafter to follow the walls of the tank within limits.

3. In combination with the skimming blade of the reciprocating bridge of a rectangular gravity separation tank, said skimming blade having rearwardly extending support arms pivotally connected at their rear ends to the understructure of the carriage and being elevatable to an upper position above the water level of the tank during the return run of the bridge; an extensible scraper assembly at each end of the skimming blade having a vertical scraper which extends toward the wall of the tank, each said assembly including a bracket attached to the end of the skimming blade, a scraper arm carried by said bracket for pivotal movement about a vertical axis ahead of the end of the skimming blade, a section of said arm having a cylindrical surface concentric with its pivotal axis and adjoining the end of the skimming blade to form therewith an operative seal, a vertical blade carried by said arm and extending toward the wall of the tank, a control lever connected to the arm, a spring having ends connected to said lever and blade assembly and rotationally biasing said arm in one direction, and a cable connecting said lever and the understruc ture of the carriage at a location such that the cable is slack when the skimming blade is in its lower position and is tightened when the skimming blade is in its upper position, the arrangement being such that as the skimming blade is pivotally raised to its upper position the cable operating against the spring turns the am and retracts the blade from the wall of the tank and as the skimming blade is lowered the effective length of the cable increases and first allows the spring to pivot the arm and move the scraper blade to engage the wall of the tank and thereafter allows the blade to follow the wall of the tank within the limits of the operative seal.

4. A skimming blade and a reciprocating supporting structure therefor to effect pushing of the floating material in a gravity separation tank to one end for removal therefrom and elevating the blade above the liquid level for return to the other end of the tank,.a laterally extensible scraper blade at each end of the skimming blade and means connected thereto and to the supporting structure such that the elevation of the blade effects lateral withdrawal of the scraper blades and relowering of the skimming blade laterally reextends the scraper blades to engage the sidewalls of the tank, said means including springs which bias the scraping blades laterally to maintain such engagement while pushing the material.

t i i

Claims

1. In combination with a reciprocating carriage carrying a skimming blade in a lower position first to push material floating between the two parallel walls of a gravity separation tank and thereafter in an upper position for return movement of the skimming blade with the carriage, extensible scraper blades carried at the ends of the skimming blade, means biasing said scraper blades so that they follow and scrape the walls of the tank as the skimming blade moves in its lower position, and a linkage connecting the scraper blade and the carriage to retract the blades as the skimming blade is elevated to provide a clearance between the scraper blades and the walls of the tank in the elevated, return position, said linkage being operable to release the scraper blades as the skimming blade is relowered for skimming.

3. In combination with the skimming blade of the reciprocating bridge of a rectangular gravity separation tank, said skimming blade having rearwardly extending support arms pivotally connected at their rear ends to the understructure of the carriage and being elevatable to an upper position above the water level of the tank during the return run of the bridge; an extensible scraper assembly at each end of the skimming blade having a vertical scraper which extends toward the wall of the tank, each said assembly including a bracket attached to the end of the skimming blade, a scraper arm carried by said bracket for pivotal movement about a vertical axis ahead of the end of the skimming blade, a section of said arm having a cylindrical surface concentric with its pivotal axis and adjoining the end of the skimming blade to form therewith an operative seal, a vertical blade carried by said arm and extending toward the wall of the tank, a control lever connected to the arm, a spring having ends connected to said lever and blade assembly and rotationally biasing said arm in one direction, and a cable connecting said lever and the understructure of the carriage at a location such that the cable is slack when the skimming blade is in its lower position and is tightened when the skimming blade is in its upper position, the arrangement being such that as the skimming blade is pivotally raised to its upper position the cable operating against the spring turns the arm and retracts the blade from the wall of the tank and as the skimming blade is lowered the effective length of the cable increases and first allows the spring to pivot the arm and move the scraper blade to engage the wall of the tank and thereafter allows the blade to follow the wall of the tank within the limits of the operative seal.

4. A skimming blade and a reciprocating supporting structure therefor to effect pushing of the floating material in a gravity separation tank to one end for removal therefrom and elevating the blade above the liquid level for return to the other end of the tank, a laterally extensible scraper blade at each enD of the skimming blade and means connected thereto and to the supporting structure such that the elevation of the blade effects lateral withdrawal of the scraper blades and relowering of the skimming blade laterally reextends the scraper blades to engage the sidewalls of the tank, said means including springs which bias the scraping blades laterally to maintain such engagement while pushing the material.