Field assembled clarifier

Large settling tanks or clarifiers of the travelling bridge type are provided in easily assembled small component sections fitting a conventional size flat bed truck for shipment to a use site to be assembled on a concrete basin requiring only a lifting crane and a small assembly crew. The knocked down clarifier eliminates heretofore required on-site time consuming building by skilled personnel and makes possible factory prefabrication of all of the clarifier parts with the exception of the concrete basin.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to the art of manufacturing clarifiers or settling 
tanks and particularly deals with travelling bridge clarifiers easily and 
quickly assembled at the use site on a concrete basin from pre-fabricated 
components and sub-assemblies forming compact bundles fitting on a 
conventional size truck for over the road shipment to the use site. 
2. Prior Art 
Travelling bridge clarifiers or settling tanks are generally too large to 
be shipped in assembled form and have been erected at the use site 
requiring services of skilled builders for a prolonged time period 
frequently under unsatisfactory weather conditions all contributing to 
large expense and delays. Travelling bridge clarifiers of the type 
disclosed and claimed in our U.S. Pat. No. 4,193,871 issued Mar. 18, 1980 
may be 15 to 25 feet in width, 40 to 75 feet in length, and 6 to 10 feet 
in depth, thus preventing over the road shipment of complete assembled 
units. Further the metal tank of the clarifier required heavy steel sheets 
and beams adding to shipment costs and installation problems. 
It would, therefore, be an improvement in the art to produce clarifiers 
with concrete basins which are poured at the use site and pre-fabricated 
sub-assemblies and interfitting components small enough to be compactly 
packed and shipped on a conventional size flat bed truck and then easily 
and quickly assembled on top of the concrete basin. 
SUMMARY OF THE INVENTION 
According to this invention, a travelling bridge clarifier is constructed 
from easily shipped compact factory built sub-assemblies and components 
for assembly on a concrete basin that has been poured at the use site. An 
excavation of desired size and shape is dug in the ground and the concrete 
basin is poured under conventional procedures used in forming swimming 
pools. The basin is generally rectangular having a flat peripheral rim or 
top edge in which upright construction bolts are anchored. The clarifier 
is shipped "knocked down" on a flat bed trailer for easy unloading by a 
crane or fork lift and component parts are successively positioned and 
assembled on the top edge or rim of the basin, secured by the anchor bolts 
and forming a baffled inlet, overflow weirs, an outlet, tracks for the 
bridge and a service platform. A pick up or suction head frame is 
suspended from the bridge to ride over the bottom of the basin. 
It is then an object of this invention to provide a travelling bridge 
clarifier of the type disclosed and claimed in U.S. Pat. No. 4,193,871 in 
a knocked down condition for assembly at the use site. 
Another object of this invention is to provide a settling tank having a 
poured concrete basin, and prefabricated sub-assemblies mounted on the 
basin constructed and arranged to remove sludge from the bottom of the 
basin and overflow clarified liquid above the basin. 
A specific object of this invention is to provide a field assembled 
travelling bridge clarifier composed of factory built sub-assemblies and 
components which are compactly packed for shipment and erected on a 
concrete basin. 
Another specific object of this invention is to provide a travelling bridge 
clarifier erected at the use site from interfitting pre-fabricated 
sub-assemblies. 
Other and further objects of this invention will become apparent to those 
skilled in this art from the following detailed description of the annexed 
sheets of drawings in which:

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS 
The clarifier 10 of this invention includes a concrete basin 11, a sidewall 
tank frame 12 mounted on the basin, a service platform 13 mounted on one 
end of the frame, a travelling bridge 14 riding on top of the frame, and a 
suction head frame 15 suspended from the travelling bridge 14. 
In accordance with this invention, the concrete basin 11 is poured in an 
excavation 16 at the use site to provide a sump 17 with sloping sidewalls 
18 and a flat peripheral rim or top edge 19. Bolts 20 (best shown in FIG. 
6) are anchored upright in this top edge 19 at spaced intervals of about 
12 inches around the periphery of the concrete basin to secure the frame 
12 on top of the basin. 
As best shown in FIG. 3, the sidewall tank frame 12 is composed of an inlet 
end section 21, a pair of elongated sidewall sections 22, a central oil 
overflow section 23, a second pair of sidewall sections 24, and an outlet 
end section 25 all arranged for mounting on the top edge 19 of the basin 
and for successive bolting together to form the unitary sidewall frame 
providing a leak proof tank extension of the sump 17. 
The sidewalls of the component sub-assemblies 21-25 are formed from heavy 
steel sheets 26, preferably about one-quarter inch thick, and structurally 
reinforced on their outer faces by welded-on channel or angle beams 
including a bottom beam 27, a central beam 28 and a top beam 29. The 
bottom beam 29 as shown in FIG. 6 is an angle beam with an outturned 
horizontal leg 29a resting on a gasket G which is placed around the rim 
edge 19 of the concrete basin 11. Steel plates 30 are provided for each 
bolt 20 and have a slot 30a receiving the bolt. The plates 30 are rigid 
rectangles about 4 inches wide, eight inches long with the slot being 
about 11/2 inches long. The inner ends of the plates overlie the leg 29a 
while the outer ends overlie bars 30b which may be welded thereto. The bar 
has a height about the same as the stacked height of the gasket G and leg 
29a. 
The bolts 20 project freely through the slots 30a of the plates 30, receive 
washers 20a bottomed on the plates 30 and nuts 20b threaded thereon cause 
the plates to clamp the leg 29a and the gasket G into sealed relation with 
the rim 19 of the basin 11. The gasket G is preferably a 35-45 durometer 
neoprene rubber. 
The end edges of the components or sub-assemblies have end face plates or 
strips 31 welded thereon with holes 32 therethrough to receive bolts 33 to 
secure the plates 31 in abutting relation with sealant or gaskets (not 
shown) interposed therebetween if desired. 
The inlet section 21 has the end steel sheet 26 extending completely across 
the width of the frame with short sidewall sheets at both ends thereof 
extending to the face plates 31. A perforated baffle plate 34 spans the 
space between these short end sheets just behind the face plates 31 and is 
welded to the sheets. Inlet pipe couplings 35 project outwardly from the 
end sheet 26 and hoods or deflector baffles 37 are welded to the inner 
face of the end sheet 26 over the entrance openings from the inlets 35. 
The central section 23 has a cross beam 38 and a steel sheet 39 paralleling 
the beam and cooperating therewith, as shown in FIG. 2 forming a trough or 
oil sump 40 with a lip edge to receive oil and floating scum on top of a 
pond of liquid being clarified in the tank. Skimmers, hereinafter 
described, push the scum to the trough or sump. A side outlet 41 drains 
the trough 40. 
The outlet section 25 has two outlet pipe couplings 42 receiving overflow 
liquid behind a baffle 43 which, like the baffle 34 spans the side plates 
26 of the end section 25. The top of this baffle 43 is serrated or toothed 
at 44 and has three recesses 45 receiving the ends of U-shaped 
longitudinal weir beams 46 also provided with toothed top edges 47. The 
front ends of these weirs 46 are supported on the cross beam 38 of the 
section 23. 
The service section 13 has a rectangular steel plate 48 with depending 
peripheral reinforcing side beams 49 spanning the inlet end of the frame 
12 and secured thereto. This platform 13 mounts an electric motor 50 
driving a ball nut actuator 51 which reciprocates an elongated screw rod 
52 to drive the bridge 41. An upright control panel P is also mounted on 
the platform 13. 
Rails 53 are mounted on top of the frame 12 to support the bridge 14. 
The bridge 14 has a rectangular base 54 with flanged wheels 55 riding the 
tracks 53. As shown in FIG. 1 the base 54 is narrower than the width of 
the frame 12 and the tracks are thus inwardly from the sides of the frame. 
Cross beams 56 are provided at intervals to reinforce the frame and to 
also support the tracks. These beams have end plates 57 (FIG. 2) which are 
bolted to the sidewalls of the sections 22 and 24. 
The bridge base platform 54 mounts a pair of electric motor driven or 
pneumatically operated suction pumps 58 and valved inlet piping 59 to the 
pumps with a flexible hose outlet 60 discharging from the pumps over the 
side of the frame 12. 
Skimmers S shown in FIG. 2 are pivotally suspended from the bridge 14 at 
spaced intervals to operate ahead of the trough or sump 40. These skimmers 
S have plastic wiper blades B (FIGS. 3 & 8) extending across the width of 
the tank frame 12 mounted on the ends of rods swingably suspended from the 
bridge frame or base 54 and raised and lowered by pneumatic jacks J also 
suspended from the bridge. On the forward (left to right) stroke of the 
bridge the blades B are lowered into the oil or scum floating on the 
liquid in the tank to drag it toward the trough 40 causing it to build up 
and overflow into the trough. On the reverse (right to left) stroke of the 
bridge the blades are raised above the oil or skum level. 
As shown in FIG. 8, the wiper blade B is mounted on the ends of a plurality 
of rods R on a rotatable cross shaft CS suspended from the bridge 14. 
As shown in FIG. 3, the inlet piping 59 suspends an open rectangular frame 
61 from which pipes 62 suspend suction heads 63. Four pairs of such heads 
are provided with the heads of each pair in end to end relation and with 
the pairs spaced longitudinally to span the bottom of the basin 11 and 
traverse a quadrant of the bottom as the bridge is reciprocated. Control 
valves are operated in sequence to connect the suction pumps to the 
suction heads as more fully described and illustrated in our aforesaid 
U.S. Pat. No. 4,193,871. 
The control panel P on the service platform 48 of the section 13 has relays 
and switches to control and monitor the operation of the drive motor 50, 
the suction pumps 58, the skimmers S, and the valves in the pipe lines 59. 
Pipe couplings of course are provided to connect the pipe sections. 
When the rame or tank sections are bolted together and the frame 12 is 
bolted on the top of the concrete basin, the interior of the tank forming 
frame may be coated with an epoxy sealant. Preferably, however, the 
coating is applied in the shop under controlled conditions and the 
precoated sections are then assembled in the field without requiring a 
field applied coating. 
The clarifier operates in the same manner as described in our aforesaid 
patent, receiving solids contaminated liquid through the inlet couplings 
35, discharging into the chamber behind the perforated baffle plate 34 and 
flowing into the tank for settling of the sludge into the bottom of the 
basin with the floating oil or scum being pulled by the skimmers S and 
overflowing into the trough 40 and the clarified liquid overflowing into 
the weirs to the outlet couplings 42. The sludge at the bottom of the 
basin is sucked out through the heads 63 and discharged at 60. 
As shown in FIG. 5 the sub-assemblies and components for mounting on the 
concrete basin are easily bundled and mounted on a flat bed truck trailer 
70. As there shown the inlet section 21, the mid oil collecting section 23 
and the outlet section section 25 are positioned in side-by-side 
longitudinally extending relation on the truck bed. The bridge rails 53 
can rest lengthwise along one side edge of the truck bed with the long 
sidewall sections 22 and the short sidewall sections 24 resting lengthwise 
behind the inlet section 21 in side-by-side relation. The service platform 
13 and the bridge section 14 can be positioned at the longitudinal center 
of the truck bed behind the outlet section 23. The drive screw 52 can then 
easily fit on the other side of the bridge section 14 with the 
longitudinal weirs 46 stacked together alongside the drive screw. Pick up 
headers 63, suction pipes 62, bolts 20 and 30, and the like components can 
be bundled together in a package 71 mounted on the rear end of the truck 
bed 70. 
All of the components and their bundles are easily removed from the truck 
bed 70 by a lifting crane or a lift fork and moved into position for 
bolting onto the top edge 19 of the concrete basin 11. 
From the above descriptions, it will therefore be clear to those skilled in 
this art that provision of an on-site poured concrete basin to form the 
sump of a travelling bridge clarifier and the provision of prefabricated 
easily shipped and easily bolted together sub-assemblies and components 
greatly simplifies and reduces the cost of clarifiers without in any way 
affecting the operating efficiency of clarifiers that heretofore had to be 
completely erected at the use site. 
While various changes and modifications might be proposed by those skilled 
in the art, it will be understood that we wish to include within the 
claims of the patent warranted hereon all such changes and modifications 
as reasonably come within our contribution to the art.