US20070072538A1

US20070072538A1 - Modular vent assembly for a sewage pumping station

Info

Publication number: US20070072538A1
Application number: US11/528,992
Authority: US
Inventors: Randall Strock
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-09-28
Filing date: 2006-09-28
Publication date: 2007-03-29

Abstract

Improved modular vent assemblies for filtering and venting gases from a sewage pumping substation. A basic non-filtering vent assembly comprises a concave plastic hood with an internal enclosure, and a stop-ring mounted in the internal enclosure. A rigid grate is secured atop the main conduit, the grate comprising a rigid circular plate with evenly-spaced apertures that forms a filter screen. A plurality of holes about the perimeter of the cap allow it to be secured to the grate by insertion of detent-pins. An enhanced filtering vent assembly comprises a stainless drum with a hinged stainless cover seated atop. The drum is equipped with a central conduit positioned coaxially with the drum by a plurality of louvers. The conduit extends downward past the louvers through a rigid grate (as above) which in this case supports a fill of activated carbon material within the drum. Powered variation of both of the foregoing embodiments are also disclosed in which a blower motor is connected to the modular vent assemblies for inducting sewer gas there through. All the foregoing embodiments provide easy maintenance and replacement of the filter cartridge, do not accumulate water vapor, are not susceptible to blockage or freezing, and may be easily retrofit to most any existing pump station exhaust vent.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application derives priority from U.S. provisional application No. 60/721,357 filed Sep. 28, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to sewage pumping stations and, more particularly, to an improved modular vent assembly for a sewage pumping station that facilitates cleaning and charging with activated charcoal for filtering of fumes.
2. Description of the Background
To maintain the aesthetics of rural neighborhoods, pumping equipment for sewage pumping stations is typically submerged in a precast concrete enclosure residing in the ground or beneath a precast concrete building within which the controls may be accessed. FIG. 1 is a perspective view of a typical precast concrete enclosure residing in the ground. Of course, the emissions from such pumping equipment can be a problem since they may be volatile, toxic, or at least odiforous. Consequently, most rural substations employ a vent pipe and filter. As seen in FIG. 1, the vent pipes 100 are typically vertically oriented to extend upwardly through the underground roof structure, terminating at a 180 degree turnbend facing downward through which the sewer gases, odors, etc., are intended to exit. The flow of the gases, etc., in the vent pipe is typically upwardly and also typically contains some water vapor, and so it is common to connect the vent pipe 100 to a blower-type filtration system 120 in which fumes are pumped out of the odor generating structure through a U-shaped trap conduit that terminates at a filter comprising a 55 gallon drum 130 filled with activated charcoal.
It is difficult to maintain these filters 130 for a variety of reasons. For one, the drums are sealed and it is difficult to gain access to the charcoal to determine whether the charcoal is saturated and in need of replacement. When replacement is called for the loose charcoal inside must be disposed of and refilled, and the drum resealed manually. Alternatively, the drum must be removed from the piping system, loaded onto a truck using equipment, and shipped away. This is an exceedingly difficult process owing to the size and weight of the drum and contents.
Moreover, when the air temperature falls below the freezing point accumulated water vapor in the U-trap may freeze to the point where the sewer vent pipe is completely blocked off. A complete blockage of the vent pipe can result in sewer gas building to explosive levels within the structure(s) . . . a very undesirable and sometimes dangerous condition.
It would be greatly advantageous to provide an improved modular vent assembly for a sewage pumping station that may be easily retrofit to existing pump station exhaust pipes to facilitate charging with activated charcoal for filtering of fumes, and which avoids the build-up of ice and debris.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an improved modular vent and filter assembly for sewer pumping stations.
It is another object to provide a modular vent and filter assembly that allows easy maintenance and replacement of a filter cartridge rather than loose charcoal or a large drum of charcoal typically exceeding 225 lbs.
It is another object to provide a modular vent and filter assembly that can be easily fabricated of either molded plastic or formed stainless steel parts.
It is still another object to provide a modular vent and filter assembly that does not accumulate water vapor and is not susceptible to blockage or freezing.
It is still another object to provide a modular vent and filter assembly that can be easily retrofit to most any existing pump station exhaust vent.
According to the present invention, the above-described and other objects are accomplished by providing an improved modular vent assembly for filtering and/or venting gases from a sewage pumping substation.
A basic non-filtering vent assembly comprises a main conduit secured overtop a pumping station vent by an annular base. The main conduit extends to a cap formed as a concave plastic hood with an internal enclosure, and a stop-ring mounted in the internal enclosure. A plurality of holes are defined in the cap around its perimeter beneath the stop ring. A rigid grate is secured atop the main conduit, the grate comprising a rigid circular plate with evenly-spaced apertures that forms a filter screen. The grate spans the main conduit and protrudes outward there from around the main conduit. The internal stop-ring of the cap has a diameter less than that of the grate so that insertion of the cap over the grate is limited by the stop ring.
An enhanced filtering vent assembly comprises a stainless drum with a hinged stainless cover seated atop. The drum is equipped with a central conduit positioned coaxially with the drum by a plurality of louvers. The conduit extends downward past the louvers through a rigid grate (as above) which in this case supports a fill of activated carbon material within the drum.
Powered variation of both of the foregoing embodiments are also disclosed in which a blower motor is connected to the modular vent assemblies for inducting sewer gas there through.
All embodiments provide easy maintenance and replacement of the vent assemblies and carbon therein. Moreover, the vent assemblies do not accumulate water vapor and are not susceptible to blockage or freezing. The present vent assemblies may be easily retrofit to most any existing pump station exhaust vent.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof when taken together with the accompanying drawings in which:
FIG. 1 is a perspective view of a typical precast concrete enclosure residing in the ground.
FIG. 2 is a perspective view of a first embodiment of a basic modular vent assembly 2 which can be used with or without a fan assembly to provide ventilation without odor control.
FIG. 3 is a perspective partially-disassembled view of the modular vent assembly 2 as in FIG. 2 with cap 10 removed from atop main conduit 20 to expose a rigid grate 50 that serves as a bird and debris screen.
FIG. 4 is a perspective view of the modular vent assembly 2 as in FIGS. 2-3 from underneath.
FIG. 5 is a side cross-section of the modular vent assembly 2 as in FIGS. 2-4.
FIG. 6 is a side cross-section of an embodiment 60 that employs the modular vent assembly as in FIGS. 1-3 with modified ductwork and supports for powered operation with a blower.
FIG. 7 is a perspective view of a second embodiment of a modular vent assembly 100 which can likewise be used with or without a fan assembly to provide ventilation, in this case with odor control.
FIGS. 8 and 9 are a top perspective view and a bottom perspective view, respectively, of the modular vent assembly 100 for odor control with cover 105 removed.
FIG. 10 is a side cross-section of an alternative embodiment of a modular vent assembly 100 similar to that of FIGS. 1-3 but installed with modified ductwork and supports for powered operation with a blower 180.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a modular vent assembly 2 for a sewage pumping station that can be easily retrofit to existing pump station exhaust vent to facilitate cleaning and/or charging with activated charcoal for filtering of fumes, and which avoids the build-up of ice and debris.
FIG. 2 is a perspective view of a first embodiment of a basic modular vent assembly 2 which can be used with or without a fan assembly to provide ventilation without odor control. The basic modular vent assembly 2 generally comprises a cap 10, and a main conduit 20 secured by base 30 to the concrete foundation of an existing pump station. For example, most existing pump stations will have a precast concrete top slab separating the underground pumping equipment from either the outside atmosphere or the control structure, and in the event of a control structure, a vent system leading up and out through an aperture in the roof of the control structure. The illustrated main conduit 20 is friction fit into the annular base 30, which mounts atop the aperture leading up and out through the precast concrete slab-foundation. The annular base 30 may be secured to the precast concrete slab-foundation by concrete expansion anchors as shown. The cap 10 is a concave hood that fits down over a main conduit 20 as will be described, the cap 10 being seated atop conduit 20 by an internal stop-ring. The main conduit 20 is secured at the bottom by a base 30 to the outlet vent of a sewage pump station. As described below, the cap 10 may be easily removed from atop main conduit 20 for cleaning.
FIG. 3 is a perspective partially-disassembled view of the modular vent assembly 2 as in FIG. 2 with cap 10 removed from atop main conduit 20 to expose a rigid grate 50 that serves as a bird and debris screen. The grate 50 is a rigid circular plate defined by evenly-spaced approximate ½″ apertures 52 that forms a filter/screen across the opening of the main conduit 20, and protrudes outward around the main conduit 20 approximately 2″. The grate 50 is permanently affixed to the main conduit 20 by tapping screw-holes through grate 50 down into the sidewalls of the main conduit 20, and securing the two together preferably by stainless screws (four are shown).
FIG. 4 is a perspective view of the modular vent assembly 2 as in FIGS. 2-3 from underneath. The grate 50 is permanently affixed to the main conduit 20 and defines a diameter greater than that of the main conduit 20. The cap 10 is formed with a diameter slightly greater than that of the grate 50 so that it can be fitted down onto the grate 50. The cap 10 is also formed with an internal stop-ring (to be described) formed with a diameter slightly less than that of the grate 50 so that the insertion of the grate 50 is limited. Preferably, the cap 10 is inserted over the grate 50 and protrudes downwardly there beneath a slight distance so that a margin extends beneath the grate 50. Opposing through-holes are defined through these lower margins of the cap 10, and removable pins 60 are inserted through the through-holes to lock the cap 10 thereon. At least two through-holes and pins 60 are preferred, and each pin 60 comprises a stainless steel pin with spring-loaded ball-detent at its distal end for locking insertion, and a loose O-ring carried in the other end for easy finger manipulation.
FIG. 5 is a side cross-section of the modular vent assembly 2 as in FIGS. 2-4 illustrating the grate 50 permanently affixed to the main conduit 20 and protruding outward there from. Cap 10 is shown at top and is preferably a molded part comprising PVC or polyethylene plastic. The main conduit 20 is likewise molded PVC or polyethylene plastic and is within a range of from 4″ to 24″ diameter, the cap 10 being sized appropriately to fit on top. The stop ring 15 (second down) is a plastic ring approximately 0.5″ high and 0.5″ thick, just sufficient to provide a seating for the cap 10. The grate 50 (third down) is a rigid circular plate, approximately 0.5″ thick, and defined by evenly-spaced apertures 52. Grate 50 may likewise be formed of molded PVC or polyethylene plastic. The base 30 comprises an annular flange with a vertical supporting collar conforming to the main pipe 20 (the main pipe 20 being frictionally inserted therein), and a wider mounting base defined by a series of radial holes for screw-mounting to the concrete slab of the pumping station lid (directly overtop the vent). The cap 10 is formed with a diameter d_cslightly greater than that d_gof the grate 50 so that it can be fitted down onto the grate 50, leaving an exposed ring of grate d_c-mthrough which gases can escape downwardly. The internal stop-ring 15 is formed with a diameter slightly less than that of the grate 50 so that the insertion of the grate 50 is limited by the stop-ring 15. The internal stop-ring 15 is affixed approximately 1″ inside the cap 10. Thus, as illustrated, the cap 10 is inserted over the grate 50 and protrudes downwardly there beneath approximately ¾″, so that a ¾″ margin extends beneath the grate 50. Opposing through-holes are defined at 90 degree intervals through the lower margins of the cap 10, and detent pins 60 (see FIG. 4) are inserted through the through-holes to lock the cap 10 thereon. The detent pins 60 may be easily removed from the cap 10 and cap 10 removed to allow cleaning and inspection.
In operation, the cap 10 is removed for cleaning or inspection. The cap 10 is then replaced until seated on the internal stop-ring 15, and the detent-pins 60 are replaced into the through-holes in the lower margins of the cap 10 to secure it in place.
The ductwork for the present vent assembly may also be modified to include a powered blower or fan.
FIG. 6 is a side cross-section of an embodiment 60 that employs the modular vent assembly as in FIGS. 1-3 with modified ductwork and supports for powered operation with a blower. In this embodiment, the main conduit 20 and base 30 of the modular vent assembly 2 are installed as described above but are connected to a conventional blower or fan assembly 80. The output of blower 80 is connected to a tubular length of neoprene 84 or other elastic material by an O-ring 82. The other side of connector 84 is connected by an O-ring 82 to the laterally-protruding stem 90 that connects to main conduit 20. In this embodiment, powering of the blower or fan assembly 80 will induct the gases through the modular vent assembly 2. The stem of T-junction conduit 90 is connected directly into the modular vent assembly 2 as described above in regard to FIGS. 2-5.
FIG. 7 is a perspective view of a second embodiment of a modular vent assembly 100 which can likewise be used with or without a fan assembly to provide ventilation, in this case with odor control. The modular vent assembly 100 generally comprises a stainless drum 110 with side handles 107 attached thereto, and a hinged stainless cover 105 seated atop. The modular vent assembly 100 is seated atop a main conduit 20 as above which is secured by a like base 30 to the concrete foundation of an existing pump station as described previously. The cover 105 is a concave hood that is pivoted on one side to the upper lip of drum 110 and which pivots down over the drum 110, where is fastened in place by a locking latch 109. The locking latch 109 is preferably a latch that draws a constriction band around the cover 105 to secure it to the drum 110, latch 109 being lockable by means of a cotter pin inserted there through.
FIGS. 8 and 9 are a top perspective view and a bottom perspective view, respectively, of the modular vent assembly 100 for odor control with cover 105 removed. As can be seen in FIG. 8, the drum 110 is equipped with a central conduit 125 positioned coaxially with the drum 110 by a plurality of louvers 120. Preferably, four louvers 120 are evenly spaced radially about the conduit 125 and extend from the inner drum 110 wall to the conduit 125. All the foregoing components including drum 110, louvers 120 and conduit 125 may be stainless steel parts joined together by welding or the like. As seen by the dotted line in FIG. 8, the louvers 120 extend down into the drum 110 from approximately 4″ below the drum opening to approximately half way down the drum 110. As seen in FIG. 9, the conduit 125 extends downward past the louvers 120 through to a rigid grate 150 similar to that described above, the grate 150 serving as a bird and debris screen and in this case to also contain activated carbon material within the drum 110. The grate 150 is a rigid circular plate defined by evenly-spaced approximate ½″ apertures 152 spanning the bottom of the drum 110. The grate 150 is permanently affixed to the drum 110 by welding or the like. The conduit 125 protrudes upward past the louvers 120 on the topside and stops approximately 2″ inside the upper rim of the drum 110. The cover 105 is concave with an approximate 2″ recess. This way, when the cover 105 is seated atop there is approximately a 4″ clearance to the end of conduit 125, and approximately 6″ of clearance to the louvers 120. The conduit 125 continues down through the grate 150 and continues approximately 4″, the protruding tip of conduit 125 being fitted with a ¼ inch O-ring 160 for sealed compression-fit connection inside the main conduit 20.
In use the cover 105 is opened and the drum 110 is filled with activated carbon. The vapor phase carbon in current use is manufactured by Calgon Corporation, type Centaur 4x6. This product is unique in that it concentrates reactants via adsorption and then promotes their reaction on the surface of the pores. When the absorption capabilities of the carbon are expended, it can be regenerated and does not present exotherm or disposal problems. To prevent the carbon from falling through the grate 150 an optional fiber filter may be inserted first. The drum 110 will contain approximately 65-225 pounds of activated charcoal in granular form, depending on its diameter. By virtue of the present configuration all gas flow is directed up through conduit 125 and down through the carbon, where it is then expelled through the grate 150. This results in 100% treatment of the gaseous flow. The above-described embodiment allows for a proper “residence time” for the odor laden air to pass through the filter carbon (internal). By testing it has been found that a certain amount of residence time helps with efficacy. The residence time is determined by the length of the pathway through the charcoal, and/or by lowering the air velocity through the charcoal. A velocity of 100 feet per minute must not be exceeded through the charcoal.
The carbon will last at least a few months and possibly longer before becoming saturated. With the present invention, it is exceedingly easy to maintain the carbon because the drum 110 can easily be gripped by handles 107 and removed from the main conduit 20, dumped, refilled and replaced onto the main conduit 20. Alternatively, the canister may be left in place and the carbon removed with a commercial wet/dry style vacuum cleaner.
If desired, the drum 110 may be equipped with an optional gas meter, and specifically a hydrogen sulfide (H2S) gas detectio meter to make monitoring the carbon absorption of the charcoal even more trouble-free. Moreover, the present configuration does not accumulate water vapor and is not susceptible to blockage or freezing. The present vent assembly may be easily retrofit to most any existing pump station exhaust vent.
As before, the ductwork for the odorless vent assembly 100 may be modified to include a powered blower or fan, although in this instance should be skid-mounted for reduced vibration.
FIG. 10 is a side cross-section of an alternative embodiment of a modular vent assembly 100 similar to that of FIGS. 1-3 but installed with modified ductwork and supports for powered operation with a blower 180. In this embodiment, the main conduit 120 is connected to the base 30 as described above, but the main conduit 120 is formed with a T-junction for connection to a conventional blower or fan assembly 80. The same modular vent assembly 100 is employed, albeit supported on a plurality of legs 330. The output of blower 80 is connected to a conduit 96 to a tubular length of rubber conduit 84, neoprene or other elastic material by a conventional screw-compression ring. The other side of connector 84 is connected to the laterally-protruding stem of the T-junction of main conduit 120. In this embodiment, powering of the blower or fan assembly 80 will induct the gases through the modular vent assembly 100 and internal carbon as described above. Due to the size and weight of the embodiment of FIG. 10, the foregoing components can be mounted on a vibration-damping skid 300 formed of metal plate or the like. The skid 300 is supported on rubber vibration-absorbing feet 310, and the skid 300 set atop the concrete slab of the pumping station lid adjacent to the vent or remotely mounted nearby, connecting to the vent structure via piping. The lower end of the main conduit 120 T-junction is connected to a pass-through hole in the skid 300, and the pass-through hole in turn connected beneath the skid 300 to the pumping station vent.
In all the foregoing embodiments, the up-and-down flow of the sewer gas induced by the concave hood 10 or cover 105 set over the central flow conduit 20 and down through the grate 50, 150 effectively sieves the gas flow, and in the embodiments of FIGS. 7-10 effectively removes odor from the gas. Moreover, the foregoing configurations provide easy maintenance and replacement, including replacement of the carbon if used. Moreover, the modular vent assemblies do not accumulate water vapor and are not susceptible to blockage or freezing. The present vent assembly may be easily retrofit to most any existing pump station exhaust vent.
Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments of the lateral-mount lower tank as well as certain variations and modifications thereto may obviously occur to those skilled in the art upon becoming familiar with said underlying concept. For instance, the main conduit 20 need not be molded PVC or polyethylene plastic. Alternately, it may be formed of smooth wall plastic, fiberglass, aluminum, or stainless steel pipe. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.

Claims

1. A modular vent assembly for venting gases from a sewage pumping substation, comprising:

a main conduit;

an annular base for securing said main conduit to a cement foundation;

a cap formed as a concave hood, said cap having an internal enclosure, a stop-ring mounted in said internal enclosure, and a plurality of holes around its perimeter beneath said stop ring;

a rigid grate comprising a rigid circular plate defined by evenly-spaced apertures to form a filter screen, said grate spanning said main conduit and protruding outward therefrom around the main conduit, the internal stop-ring of the cap having a diameter less than that of the grate so that insertion of the cap over the grate is limited by the stop ring.

2. The modular vent assembly according to claim 1, further comprising a plurality of removable pins inserted through said cap beneath said grate for securing said cap on said grate.

3. The modular vent assembly according to claim 2, wherein the evenly-spaced apertures of said grate comprise approximately ½″ diameter apertures.

4. The modular vent assembly according to claim 3, wherein the cap is formed as a concave plastic hood.

5. The modular vent assembly according to claim 1, further comprising a blower motor, said main conduit comprises a T-junction in fluid communication with said blower motor for inducting sewer gas through said modular vent assembly.

6. A modular vent assembly for venting gases from a sewage pumping substation, comprising:

a main conduit for connection to a sewer vent of said sewage pumping substation to vent gas therefrom;

an annular base for securing said main conduit to a cement foundation of said sewage pumping substation;

a cylindrical drum forming an internal enclosure having a top and a bottom, said main conduit passing axially up through said drum and terminating proximate the top;

a concave cover hinged at the top of said cylindrical drum for closing off the top of said drum and directing gas from the vent of said sewage pumping down through said drum;

a plurality of louvers attached axially about said main conduit and coaxially supporting said main conduit in said drum.

a rigid grate comprising a rigid circular plate defined by evenly-spaced apertures to form a filter screen, said grate substantially spanning the bottom of the cylindrical drum except to pass said main conduit; and

a supply of activated charcoal filling a majority of said drum atop said grate.

7. The modular vent assembly according to claim 6, further comprising a latch for securing said cover onto said drum.

8. The modular vent assembly according to claim 7, wherein said latch is a locking latch to prevent removal.

9. The modular vent assembly according to claim 6, wherein the evenly-spaced apertures of said grate comprise approximately ½″ diameter apertures.

10. The modular vent assembly according to claim 6, wherein the cover is formed as a concave stainless steel cover and the drum is formed of stainless steel.

11. The modular vent assembly according to claim 5, wherein the plurality of louvers further comprises four louvers arranged at 90 degree intervals about the main conduit.

12. The modular vent assembly according to claim 5, further comprising a blower motor, said main conduit further comprising a T-junction in fluid communication with said blower motor for inducting sewer gas through said modular vent assembly.

13. The modular vent assembly according to claim 12, wherein said blower motor inducts sewer gas through said modular vent assembly at a velocity of less than 100 feet per minute to ensure a minimum carbon exposure time of one second.

14. A modular vent assembly for venting gases from a sewage pumping substation, comprising:

a skid having vibration damping feet;

a blower motor mounted on said skid

a main conduit formed with a T-junction with a coupling through said skid to a sewer vent of said sewage pumping substation to vent gas there from, and a second coupling attached to said blower motor;

a plurality of legs supporting said drum on said skid;

a supply of activated charcoal filling a majority of said drum atop said grate.

15. The modular vent assembly according to claim 14, further comprising a locking latch for securing said cover onto said drum.

16. The modular vent assembly according to claim 14, further comprising a plurality of vibration-damping feet attached underneath said skid.

17. The modular vent assembly according to claim 14, wherein the evenly-spaced apertures of said grate comprise approximately ½″ diameter apertures.

18. The modular vent assembly according to claim 14, wherein the plurality of louvers further comprises four louvers arranged at 90 degree intervals about the main conduit.

19. The modular vent assembly according to claim 14, wherein said blower motor inducts sewer gas through said modular vent assembly at a velocity of less than 100 feet per minute to ensure a minimum carbon exposure time of one second.