Controlled pressure sewer system

Claim 2

In a sewer system having a generally horizontal trunk line and a plurality of feeder lines connected thereto for conveying sewage from sources at different elevations above the elevation of the trunk line, the method of conveying sewage from the plurality of sources into the trunk line without the need for check valves to inhibit back flow from the trunk line into the feeder lines, and for conveying sewage through the trunk line despite the absence of an elevation gradient along the trunk line in the direction of desired sewage flow, comprising the steps of: (a) dividing the trunk line into a plurality of serially connected sections; (b) establishing a predetermined pressure at the upstream end of each of the plurality of sections and restricting sewage flow at the downstream end of each of the plurality of sections to thereby provide a decreasing pressure gradient along the length of each of the plurality of sections in the direction of desired sewage flow despite the absence of an elevation gradient in the direction of desired sewage flow; and, (c) connecting each of the feeder lines into the trunk line at a point where the pressure at the downstream end of the feeder line as a result of the elevation of the source above the trunk line is greater than the pressure at that point in the trunk line to thereby eliminate the need for a check valve to prevent back flow from the trunk line into the feeder line.

Claim 3

The method of claim 1 wherein the step of establishing a predetermined pressure at the upstream end of each of the plurality of sections of the trunk line includes the steps of: (a) providing a container for each section in fluid communication at its lower end with the upstream end of the section of the trunk line, the container having sufficient vertical height to establish a hydrostatic head equal to the desired predetermined pressure at the upstream end of the section; and, (b) pumping sewage from the downstream end of the immediately preceding section of the trunk line into the upper end of the container.

Claim 4

The method of claim 2 wherein the step of pumping sewage includes pumping the sewage into the container at a rate greater than the rate of flow of the sewage through the trunk line to maintain the container and the trunk line full of sewage.

Claim 5

A sewer system in which the flow of sewage towards a destination point is maintained despite the absence of an elevation gradient along the path of sewage flow, and in which the back flow of sewage towards a source is substantially inhibited without the need for check valves, said system comprising: a generally horizontal trunk line divided into a plurality of serially connected sections; means for establishing a predetermined pressure at the upstream end of each section; means for restricting sewage flow at the downstream end of each section to thereby establish a decreasing pressure gradient along the length of each section in the direction of sewage flow despite the absence of an elevation gradient along the trunk line; and, at least one feeder line for supplying sewage to said trunk line from a sewage source located at an elevation above the trunk line, said feeder line being connected to the trunk line at a point where the pressure in the trunk line is less than the pressure at the downstream end of the feeder line resulting from the elevation of the source, to thereby eliminate the need for a check valve to inhibit back flow of sewage from the trunk line to the source.

Claim 6

A sewer system in which the flow of sewage towards a destination point is maintained despite the absence of an elevation gradient along the path of sewage flow, and in which the back flow of sewage towards a source is substantially inhibited without the need for check valves, said system comprising: a generally horizontal trunk line divided into a plurality of serially connected sections; means for establishing a predetermined pressure at the upstream end of each section; means for restricting sewage flow at the downstream end of each section to thereby establish a decreasing pressure gradient along the length of each section in the direction of sewage flow despite the absence of an elevation gradient along the trunk line; and, at least one feeder line for supplying sewage to said trunk line from a sewage source located at an elevation above the trunk line, said feeder line being connected to the trunk line at a point where the pressure in the trunk line is less than the pressure at the downstream end of the feeder line resulting from the elevation of the source, to thereby eliminate the need for a check valve to inhibit back flow of sewage from the trunk line to the source.

Claim 7

The system of claim 4 wherein said pressure establishing means includes: a container in fluid communication at its lower end with the upstream end of a section of the trunk line, said container having a sufficient vertical height to establish a hydrostatic head equal to said predetermined pressure; and, means for conveying sewage from the downstream end of the immediately preceding trunk line section into the upper end of said container to provide the hydrostatic head and thereby establish said predetermined pressure.

Claim 8

The system of claim 5 wherein said sewage conveying means includes a well for receiving sewage from the downstream end of the immediately preceding section and a pump for pumping the received sewage from the well into the upper end of the container.

Claim 9

The system of claim 6 wherein said pump pumps sewage into the container at a rate greater than the rate of flow of sewage through said trunk line to thereby maintain said container and said trunk line full of sewage.

Claim 14

A sewage system in which sewage is conveyed to a destination point despite the absence of an elevation gradient along the path of sewage flow in the direction of sewage flow, comprising: a trunk line divided into a plurality of serially connected sections each having an open upright portion at the upstream end hereof; means for establishing a predetermined positive pressure at the upstream end of each section including a pump for feeding sewage from the downstream end of each section into the open upright portion at the upstream end of the immediately following section of the trunk line to thereby maintain at the upstream end of each section the sewage at a predetermined level above the downstream end of each section to thereby produce a hydrostatic head at the upstream end of each open section which is equal to said predetermined pressure; and, means for restricting sewage flow at the downstream end of each section to maintain a predetermined pressure gradient in each section which decreases along the path of travel of the sewage in each section in the direction of sewage flow and thereby induces sewage flow despite the absence of an elevation gradient along the trunk line in the direction of sewage flow.

Claim 15

A sewage system in which sewage is conveyed to a destination point despite the absence of an elevation gradient along the path of sewage flow in the direction of sewage flow, comprising: a trunk line divided into a plurality of serially connected sections each having an open upright portion at the upstream end hereof; means for establishing a predetermined positive pressure at the upstream end of each section including a pump for feeding sewage from the downstream end of each section into the open upright portion at the upstream end of the immediately following section of the trunk line to thereby maintain at the upstream end of each section the sewage at a predetermined level above the downstream end of each section to thereby produce a hydrostatic head at the upstream end of each open section which is equal to said predetermined pressure; and, means for restricting sewage flow at the downstream end of each section to maintain a predetermined pressure gradient in each section which decreases along the path of travel of the sewage in each section in the direction of sewage flow and thereby induces sewage flow despite the absence of an elevation gradient along the trunk line in the direction of sewage flow.

Claim 16

The system of claim 10 further including at least one feeder line for supplying sewage to said trunk line from a sewage source located at a height above the trunk line, said feeder line being connected to a point on the trunk line at which the pressure in the trunk line is less than the pressure at the downstream end of the feeder line resulting from the elevation of the sewage source above the trunk line, to inhibit back flow of sewage from the trunk line to the feeder line without the need for check valves.

Claim 17

A sewer system for conveying sewage through a generally horizontal trunk line despite the absence of an elevation gradient along the flow path of the sewage, and for conveying sewage from a plurality of sources located at different elevations above the trunk line into the trunk line without the need for check valves to inhibit the back flow of sewage from the trunk line toward the sources, said system comprising: a generally horizontal trunk line divided into a plurality of serially connected sections; a plurality of containers having respective upper and lower ends, one container being provided for each of the sections of said trunk line, each of said containers having a sufficient vertical height to establish a predetermined hydrostatic head at the lower end thereof when filled with sewage, the lower end of each container being connected to the upstream end of an associated trunk line section and in fluid communication therewith to provide a predetermined pressure at the upstream end of each trunk line section which is equal to said hydrostatic head; a well in fluid communication with the downstream end of each of said sections for receiving the sewage flowing in the associated section; means for pumping sewage from the well associated with a first trunk line section into the upper end of the container associated with the upstream end of the next following trunk line section, said pumping means being actuable to pump sewage into said container at a rate greater than the rate at which sewage flows through the trunk line to maintain said container full of sewage and thereby provide said hydrostatic head, the upper end of said container being in fluid communication with the well associated with said first section to enable said well to receive any spillover from the container caused by the pumping rate of said pumping means; means for controlling said pumping means to actuate said pumping means when the sewage in said well reaches a first level and to deactivate the pumping means when the sewage in the well reaches a second level lower than said first level; means for restricting flow located at the downstream end of each of said trunk line sections to maintain each of said sections full of sewage and thereby provide a pressure gradient in each section which decreases along the path of flow of the sewage to induce the flow of sewage in each trunk line section despite the absence of an elevation gradient along the flow path of the sewage; and, a plurality of feeder lines for conveying sewage from a plurality of sewage sources located at different elevations above the trunk line into the trunk line, said feeder lines being respectively connected in fluid communication with said trunk line at a point on the trunk line where the pressure in the trunk line is less than the pressure at the downstream end of the feeder line resulting from the elevation of an associated source above the trunk line, to thereby inhibit the back flow of sewage from the trunk line into the feeder lines without the need for check valves.

Claim 18

A sewer system for conveying sewage through a generally horizontal trunk line despite the absence of an elevation gradient along the flow path of the sewage, and for conveying sewage from a plurality of sources located at different elevations above the trunk line into the trunk line without the need for check valves to inhibit the back flow of sewage from the trunk line toward the sources, said system comprising: a generally horizontal trunk line divided into a plurality of serially connected sections; a plurality of containers having respective upper and lower ends, one container being provided for each of the sections of said trunk line, each of said containers having a sufficient vertical height to establish a predetermined hydrostatic head at the lower end thereof when filled with sewage, the lower end of each container being connected to the upstream end of an associated trunk line section and in fluid communication therewith to provide a predetermined pressure at the upstream end of each trunk line section which is equal to said hydrostatic head; a well in fluid communication with the downstream end of each of said sections for receiving the sewage flowing in the associated section; means for pumping sewage from the well associated with a first trunk line section into the upper end of the container associated with the upstream end of the next following trunk line section, said pumping means being actuable to pump sewage into said container at a rate greater than the rate at which sewage flows through the trunk line to maintain said container full of sewage and thereby provide said hydrostatic head, the upper end of said container being in fluid communication with the well associated with said first section to enable said well to receive any spillover from the container caused by the pumping rate of said pumping means; means for controlling said pumping means to actuate said pumping means when the sewage in said well reaches a first level and to deactivate the pumping means when the sewage in the well reaches a second level lower than said first level; means for restricting flow located at the downstream end of each of said trunk line sections to maintain each of said sections full of sewage and thereby provide a pressure gradient in each section which decreases along the path of flow of the sewage to induce the flow of sewage in each trunk line section despite the absence of an elevation gradient along the flow path of the sewage; and, a plurality of feeder lines for conveying sewage from a plurality of sewage sources located at different elevations above the trunk line into the trunk line, said feeder lines being respectively connected in fluid communication with said trunk line at a point on the trunk line where the pressure in the trunk line is less than the pressure at the downstream end of the feeder line resulting from the elevation of an associated source above the trunk line, to thereby inhibit the back flow of sewage from the trunk line into the feeder lines without the need for check valves.

Claim 19

The method of claim 8 including the step of pumping the effluent from the downstream end of each of the lateral sections into the top of the upright section of the immediately downstream section of pipeline.