Sewage pumping station

A sewage pumping or lift station is mounted on the upper edge of a standard concrete wet well. A vertical partition divides the station into a machinery chamber and an access chamber that are hermetically isolated from each other. The floor of the machinery chamber is imperforate except for a hole through which a sewage inlet pipe passes and that hole is sealed by weldments attaching the inlet pipe to the floor; this hermetically isolates the machinery chamber from the sewer gases in the wet well. Any other components which must communicate with the wet well pass through sealed holes in the vertical partition.

BACKGROUND OF THE INVENTION 
This invention relates to sewage pump station construction and more 
particularly to improvements which prevent noxious sewer gases such as 
methane and hydrogen sulfide from entering the enclosure in which 
machinery is housed. 
Sewage pumping stations of the type that are mounted on top of a concrete 
sewage wet wall ordinarily have numerous holes and openings in the bottom 
deck plate or floor of the machinery enclosure. Bolts and other fasteners, 
connecting rods, rotating shafts, and electrical components and wires 
commonly extend through such holes, and access to the underside of the 
station for repair or maintenance has been provided by a removable lid 
covering a manway opening in such a bottom deck plate. Attempts to 
hermetically seal such holes and openings with conventional means such as 
gaskets have failed because bolts loosen from vibration and flexure of the 
deck plate, shafts and bushings wear loose, and all such components are 
subject to deterioration from the moisture and corrosive gasses that are 
almost always present at the underside of the deck plate. Breaking of the 
hermetic seal in any of these ways results in sewer gases entering the 
machinery enclosure where they present health hazards to workers and an 
explosion risk because the pumps are electrically powered. Also, any 
omission of a part or any error in the way such components are installed 
or sealed usually permit entry of these gases. 
OBJECTIVES OF THE INVENTION 
Accordingly, it is an object of this invention to provide an improved wet 
well mounted sewage pumping station. 
Another object is to prevent sewer gases from entering the machinery 
compartment of a pump station. 
Another object is to provide continuous access to the underside of a sewage 
pump station without causing an explosion hazard. 
Another object is to protect workers from sewer gases. 
Another object is to provide a rugged, relatively low cost, hazard free wet 
well mounted sewage pumping station that can be easily repaired and 
maintained, and which does not possess defects found in similar prior art 
devices. 
Other objects and advantages will be apparent from the specification and 
claims and the scope of the invention will be set forth in the claims.

DESCRIPTION OF THE INVENTION 
The drawing shows a sewage pumping station 10 mounted on the top edge 11 of 
a standard cylindrical concrete wet well 12. Sewage enters wet well 12 
through an inlet pipe 13. 
Station 10 has a generally horizontal, flat, metal floor 15 that overlies 
and is fitted on to the upper edge 11 of wet well 12. A generally right 
circular cylindrical, metal peripheral wall 16 extends vertically upwardly 
from floor 15 and defines the interior of station 10. Wall 16 is welded to 
the upper surface of floor 15 around its entire lower edge so as to 
provide a hermetic seal therebetween. A generally vertical flat metal 
partition 17 extends upwardly from floor 15 within the confines of wall 
16. The bottom and side edges of partition 17 are welded to floor 15 and 
to wall 16 so as to divide the interior of station 10 into a machinery 
chamber 18 and an access chamber 19 which are hermetically isolated from 
each other. At least a portion of each of chambers 18 and 19 is directly 
vertically above the open interior of wet well 12. 
Machinery chamber 18 contains the conventional operating components of a 
sewage pumping station, such as one or more sewage pumps 20 and 
electrically operated vacuum pumps 21 for priming pumps 20. Electric 
motors 23 power pumps 20, and conventional electric circuitry in a control 
panel 24 regulates the operation of the motors. Pumps 20 are located 
directly above wet well 12, and sewage inlet conduit means 25 extends 
vertically downwardly from each pump and terminates adjacent the bottom of 
the wet well. Each conduit means 25 includes a unitary cylindrical metal 
pipe 27 that extends downwardly from its associated pump 20 into the top 
of wet well 12 thru a hole 28 in floor 15. Holes 28 are hermetically 
sealed because pipes 27 are welded at 29 to the entire edge of floor 15 
that defines these holes. An annular flange 30 at the upper end of each 
pipe 27 is connected to a pump 20 by bolts 32 threaded into a flange 33 on 
pump 20, and an annular flange 34 at the lower end of each pipe 27 is 
connected to another component 35 of a conduit means 25 by bolts 36 
threaded into nuts 37. Thus floor 15 is imperforate except for holes 28 
and chamber 18 is hermetically isolated from the inside of wet well 12. 
The top of machinery chamber 18 is closed by removable means such as a 
pivotable cover 38. Chamber 18 may also include conventional components 
such as a ladder, sump and sump pump, ventilators, check valves, and 
fit-up plates around conduit means 25, but such components have been 
omitted from the drawing because their details are not a part of this 
invention. 
In access chamber 19 a manway opening 40 in floor 15 provides continous 
access to the inside of wet well 12 beneath station 10. The circuitry for 
controlling the operation of pump station 10 will usually include 
conventional electrical components, such as displacement switches 41, for 
sensing the level of the sewage in wet well 12. As sewage rises and falls 
in wet well 12 one or more of the switches 41 are activated of 
deactivated, and this turns one or both pumps 20 on or off in known 
manner. When either pump 20 is in operation, sewage is drawn upwardly 
through inlet conduit means 25 and is pumped through outlet conduit means 
42 into a discharge pipe 43. Switches 41 are suspended in wet well 12 on 
electrical conductor wires 44 that pass horizontally through a hole 45 
near the top of partition 17 that is hermetically sealed by gasket means 
46. The discharge pipe 47 of a sump pump (not shown) also passes through 
an elevated hole 48 in partition 17 that is hermetically sealed by 
suitable gasket means. This permits such a sump pump to discharge into wet 
well 12 without the need for holes through floor 15. A separate removable 
cover 49 closes the top of access chamber 19. Cover 49 should not be 
sealed shut to permit escape of gasses from chamber 19. 
It has thus been shown that by the practice of this invention the machinery 
chamber 18 of a sewage pumping station 10 can be hermetically isolated 
from the inside of the wet well 12 upon which station 10 is mounted. This 
is accomplished by keeping the floor 15 of chamber 18 imperforate except 
for inlet conduit holes 28 which are sealed by welding, and by eliminating 
the need for seals, fasteners, and bushings that pass through the floor. 
Continuous access to the underside of station 10 and to the inside of wet 
well 12 for repair or maintenance is provided through manway opening 40 in 
floor 15 within the confines of access chamber 19. Any components of 
station 10 other than conduit means 25 that must be in communication with 
the inside of wet well 12 are passed through sealed holes in partition 17. 
Thus, control wires 44 pass through a sealed hole 45 and sump pump 
discharge pipe 47 passes through sealed hole 48. The seals for the 
elevated holes 45 and 48 in partition 17 are subject to much less wear, 
damage, and corrosion than the same seals would be in floor 15, and 
therefore will keep chamber 18 hermetically isolated from chamber 19 for 
longer periods without needing replacement. Also, since the sewer gases in 
chamber 19 can easily escape to the atmosphere through unsealed cover 49, 
they are not likely to pass through any faulty seal in partition 17 into 
the closed machinery chamber 18. 
While the present invention has been described with reference to a 
particular embodiment, it is not intended to illustrate or describe herein 
all of the equivalent forms or ramifications thereof. Also, the words used 
are words of description rather than limitation, and various changes may 
be made without departing from the spirit or scope of the invention 
disclosed herein. It is intended that the appended claims cover all such 
changes as fall within the true spirit and scope of the invention.