Sewage lift station gas trap

Claim 2

A sewage lift station comprising a closed tank having an effluent inlet and an effluent outlet in the lower portion thereof, pump means connected to said outlet for pumping effluent from said tank, means responsive to the fluctuating effluent level in said tank for energizing said pump means when said effluent rises to a predetermined upper level and for deenergizing said pump means when said effluent drops to a predetermined lower level, a space in the upper portion of said tank in which sewer gas may collect, variable volume means connected to said tank and operative normally to isolate the interior thereof from the surrounding atmosphere, said variable volume means being responsive to the difference between atmospheric pressure and the gas pressure in said tank to maintain the gas pressure in said tank at substantially atmospheric pressure as the effluent level rises and falls between said predetermined upper and lower levels within said tank, whereby offensive odors from the interior of said tank and objectionable gaseous discharges are substantially eliminated from the atmosphere surrounding said tank.

Claim 3

A sewage lift station as defined in claim 1, and vent means for venting innocuous quantities of said sewer gas to the atmosphere when an excess of said gas accumulates over a period of time and when an abnormal rise in the effluent level in said tank occurs.

Claim 4

A sewage lift station as defined in claim 2, said variable volume means comprising a flexible bag positioned within said tank, the exterior of said bag subjected to the gas pressure in said tank while the interior thereof is subjected to the pressure of the surrounding atmosphEre.

Claim 5

A sewage lift station as defined in claim 2, said variable volume means comprising a flexible bag positioned outside said tank, the interior of said bag being subjected to the gas pressure in said tank while the exterior thereof is subjected to the pressure of the surrounding atmosphere.

Claim 6

A sewage lift station as defined in claim 2, said vent means comprising pressure and vacuum relief valve means connected to said tank and operative to vent gases from said tank to the surrounding atmosphere when the gas pressure in said tank tends to increase above atmospheric pressure and to permit air from the atmosphere to enter said tank when a vacuum tends to be created therein.

Claim 7

A sewage lift station as defined in claim 2, wherein the maximum volume of said variable volume means corresponds substantially to the volume of gas in said tank displaced as said effluent fluctuates between said predetermined limits.

Claim 8

A sewage lift station comprising a closed tank having an effluent inlet and an effluent outlet in the lower portion thereof, pump means connected to said outlet for pumping effluent from said tank, means responsive to the fluctuating effluent level in said tank for energizing said pump means when said effluent rises to a predetermined upper level and for deenergizing said pump means when said level drops to a predetermined lower level, a space in the upper portion of said tank in which sewer gas may collect, and operative means connected to said tank operative normally to isolate the interior thereof from the surrounding atmosphere, thereby preventing egress of said sewer gas from the tank as the effluent level rises and falls between said predetermined upper and lower levels within said tank, and to vent innocuous quantities of said sewer gas to the atmosphere when an excess of said gas accumulates over a period ot time and when an abnormal rise in the effluent level in said tank occurs, said operative means comprising a breathing assembly including a fitting freely extending through a wall opening in said tank and having an annular flange at one end normally sealingly seated relative to said opening, and variable volume means connected to said fitting and being responsive to the gas pressure in said tank to maintain said gas pressure at substantially atmospheric pressure, whereby offensive odors from the interior of said tank and objectionable gaseous discharges are substantially eliminated from the atmosphere surrounding said tank.

Claim 9

A sewage lift station comprising a closed tank having an effluent inlet and an effluent outlet in the lower portion thereof, pump means connected to said outlet for pumping effluent from said tank, means responsive to the fluctuating effluent level in said tank for energizing said pump means when said effluent rises to a predetermined upper level and for deenergizing said pump means when said level drops to a predetermined lower level, a space in the upper portion of said tank in which sewer gas may collect, and operative means connected to said tank operative normally to isolate the interior thereof from the surrounding atmosphere, thereby preventing egress of said sewer gas from the tank as the effluent level rises and falls between said predetermined upper and lower levels within said tank, and to vent innocuous quantities of said sewer gas to the atmosphere when an excess of said gas accumulates over a period ot time and when an abnormal rise in the effluent level in said tank occurs, said operative means comprising a breathing assembly including a fitting freely extending through a wall opening in said tank and having an annular flange at one end normally sealingly seated relative to said opening, and variable volume means connected to said fitting and being responsive to the gas pressure in said tank to maintain said gas pressure at substantially atmospheric pressure, whereby offensive odors from the interior of said tank and objectionable gaseous discharges are substantially eliminated from the atmosphere surrounding said tank.

Claim 10

A sewage lift station as defined in claim 7, said variable volume means comprising a flexible bag positioned within said tank, the interior of said bag being exposed to atmospheric pressure through said fitting and the exterior thereof being exposed to sewer gas pressure in said tank, said bag collapsing and expanding as the sewage level in said tank rises and falls to normally maintain the sewer gas pressure substantially equal to atmospheric pressure.

Claim 11

A sewage lift station as defined in claim 8, wherein the outer periphery of said fitting is spaced from the tank wall portion defining said wall opening to provide an annular passageway therebetween, said bag being suspended from said fitting and the weight of said bag normally retaining said flange sealingly seated with said external wall surface around said opening, said breathing assembly being operative to unseat said flange and vent said sewer gas through said passage when said sewer gas pressure exceeds atmospheric pressure by a predetermined amount sufficient to substantially fully collapse said flexible bag and unseat said annular flange relative to said external wall surface.

Claim 12

A sewage lift station as defined in claim 8, wherein the maximum volumetric size of said bag corresponds substantially to the volume of gas in said tank displaced as said effluent level fluctuates between said limits.

Claim 13

A breathing assembly for use in a sewage lift station which includes a closed tank comprising a tubular fitting adapted to extend through an opening in the tank in spaced relation with the wall portion of the tank defining the opening to form an annular passage therebetween and including a flange on one end thereof adapted to be sealingly seated outside the tank around the opening, a flexible bag connected to the other end of said fitting and adapted to be positioned within the tank, said bag being in open communication through said fitting with the atmosphere surrounding said tank so that said bag expands and contracts in response to the difference between atmospheric pressure and the pressure in said tank to thereby maintain the pressure in said tank at substantially atmospheric pressure, and said bag having means permitting the escape of gas from the interior thereof into the tank to prevent an excessive rupturing pressure differential between the inside and outside of the bag.

Claim 14

A breathing assembly for use in a sewage lift station which includes a closed tank comprising a tubular fitting adapted to extend through an opening in the tank in spaced relation with the wall portion of the tank defining the opening to form an annular passage therebetween and including a flange on one end thereof adapted to be sealingly seated outside the tank around the opening, a flexible bag connected to the other end of said fitting and adapted to be positioned within the tank, said bag being in open communication through said fitting with the atmosphere surrounding said tank so that said bag expands and contracts in response to the difference between atmospheric pressure and the pressure in said tank to thereby maintain the pressure in said tank at substantially atmospheric pressure, and said bag having means permitting the escape of gas from the interior thereof into the tank to prevent an excessive rupturing pressure differential between the inside and outside of the bag.

Claim 15

A breathing assembly for use in a sewage lift station as defined in claim 11, said bag adapted to correspond volumetrically in size to the volume of gas displaced in the tank by the fluctuation of sewage effluent between predetermined limits in the tank.

Claim 16

A sewage lift station comprising a tank having an effluent inlet and an effluent outlet in the lower portion thereof, a space in the upper portion thereof in which sewer gas may collect, a breathing assembly connected to said tank and operative normally to isolate the interior of said tank from the surrounding atmosphere and to maintain said sewer gas against egress from the tank as the effluent level rises and falls between predetermined levels within said tank, said breathing assembly including a fitting freely extending through a wall opening in said tank in spaced relation from the tank wall portion defining the opening to provide an annular passage therebetween, an annular flange at one end of said fitting normally sealingly seated relative to said opening, a variable volume flexible bag connected to said fitting and positioned within said tank, the interior of said bag being exposed to atmospheric pressure through said fitting and the exterior thereof being exposed to sewer gas pressure in said tank, said bag collapsing and expanding as the effluent level in said tank rises and falls to normally maintain the sewer gas pressure within the tank substantially equal to atmospheric pressure, said flexible bag comprising means permitting the escape of the gas from the interior thereof into said space to prevent rupture of said bag due to excessive pressure internally thereof, and said breathing assembly being operative to vent sewer gas through said annular passage when said sewer gas pressure exceeds atmospheric pressure by a predetermined amount sufficient to substantially fully collapse said flexible bag and unseat said annular flange relative to said wall opening.

Claim 17

A sewage lift station comprising a tank having an effluent inlet and an effluent outlet in the lower portion thereof, a space in the upper portion thereof in which sewer gas may collect, a breathing assembly connected to said tank and operative normally to isolate the interior of said tank from the surrounding atmosphere and to maintain said sewer gas against egress from the tank as the effluent level rises and falls between predetermined levels within said tank, said breathing assembly including a fitting freely extending through a wall opening in said tank in spaced relation from the tank wall portion defining the opening to provide an annular passage therebetween, an annular flange at one end of said fitting normally sealingly seated relative to said opening, a variable volume flexible bag connected to said fitting and positioned within said tank, the interior of said bag being exposed to atmospheric pressure through said fitting and the exterior thereof being exposed to sewer gas pressure in said tank, said bag collapsing and expanding as the effluent level in said tank rises and falls to normally maintain the sewer gas pressure within the tank substantially equal to atmospheric pressure, said flexible bag comprising means permitting the escape of the gas from the interior thereof into said space to prevent rupture of said bag due to excessive pressure internally thereof, and said breathing assembly being operative to vent sewer gas through said annular passage when said sewer gas pressure exceeds atmospheric pressure by a predetermined amount sufficient to substantially fully collapse said flexible bag and unseat said annular flange relative to said wall opening.

Claim 18

A breathing assembly for use in a sewage lift station which includes a closed tank in which sewage effluent collects and fluctuates in level between predetermined upper and lower levels, said assembly comprising tubular means adapted to extend through an opening in said tank, a flexible bag connected to one end of said tubular means and adapted to be positioned within the tank, said bag being in open communication through said tubular means with the atmosphere surrounding said tank so that said bag expands and contracts in response to the difference between atmospheric pressure and the pressure in said tank to thereby maintain the pressure in said tank at substantially atmospheric pressure, and said bag corresponding volumetrically in size to the volume of gas displaced in the tank by the fluctuation of the effluent in the tank between the predetermined upper and lower levels.

Claim 19

A breathing assembly for use in a sewage lift station which includes a closed tank in which sewage effluent collects and fluctuates in level between predetermined upper and lower levels, said assembly comprising tubular means adapted to extend through an opening in said tank, a flexible bag connected to one end of said tubular means and adapted to be positioned within the tank, said bag being in open communication through said tubular means with the atmosphere surrounding said tank so that said bag expands and contracts in response to the difference between atmospheric pressure and the pressure in said tank to thereby maintain the pressure in said tank at substantially atmospheric pressure, and said bag corresponding volumetrically in size to the volume of gas displaced in the tank by the fluctuation of the effluent in the tank between the predetermined upper and lower levels.