Power-operated extensible skimming blade

Claim 2

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.

Claim 3

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.

Claim 4

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.

Claim 5

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.

Claim 6

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.

Claim 7

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.

Claim 8

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.