Infiltration-inflow sewer line analyzer

• US 4,295,197 A
• Filed: 12/17/1979
• Issued: 10/13/1981
• Est. Priority Date: 05/12/1978
• Status: Expired due to Term

• Current Assignee: Peter D. Petroff
• Original Assignee: Peter D. Petroff
• Inventors: Petroff, Peter D.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US06/104,540
• Time in Patent Office: 666 Days
• Field of Search: 364/510, 73/299, 73/195
• US Class Current: 702/45
• CPC Class Codes: G01M 3/2815 using pressure measurements

Abstract

A method and means of determining inflow (undesired pipe drains to a sewer) and infiltration (sewer pipe leakage) into sewer lines by a coordinate measurement of pressure in sewer pipes at several locations, particularly measuring flow during rainfall and for a discrete period thereafter and comparing the results with dry periods.

Claims

1. A system of measurement of flow gains between ends of a sewer line, said line extending between an upstream manhole and a downstream manhole, and having a first sewer pipe with an exit end at the downstream manhole, and there being a second sewer pipe having an exit feeding said upstream manhole, comprising:

first and second monitoring assemblies, said first monitoring assembly being positioned in the end region of said first sewer pipe, and said second monitoring assembly being positioned in an end region of said second sewer pipe, and wherein each monitoring assembly comprises;

liquid level sensing means for sensing liquid level and providing as an output a signal which is a function of liquid level,

mounting means for mounting and positioning said liquid level sensing means in said end regions of said sewer pipes, and

sampling and recording means for periodically and synchronously, as between monitoring assemblies, and responsive to said liquid level sensing means, sampling and recording time identified said signals over a selected period of time;

conversion means responsive to selected recorded signals for converting said signals into liquid flow rates;

computation means responsive to said conversion means and dry and rainy day samples of values from each of said monitoring assemblies supplied said conversation means for (1) determining the difference between like timed, time of day, dry and rainy day flows from said first sewer pipe, (2) determining the difference between like timed, time of day, dry and rainy day flows from said second sewer pipe, and (3) determining the differences between said difference flows obtained as per (1) and (2) of this paragraph; and

control means for selectively fetching samples from said sampling and recording means and placing same in said conversion means, whereby readings and computations may be made at selected times, and thereby measurements may be made during rainfalls which are representative of inflow into said pipe, and measurements made following rainfalls are representative of infiltration into a said pipe.

2. A system of measurement of flow gains as set forth in claim 7 wherein:

said downstream manhole is connected to and extends upward from an exit end of said first sewer pipe;

each said liquid level sensing means comprises pressure sensing means;

said conversion means comprises;

first pressure-to-flow conversion means responsive to a pressure signal from an exit end of said first sewer pipe, radius of said first sewer pipe, and slope of said first sewer pipe for determining a first flow value,

second pressure-to-flow conversion means responsive to pressure signals from both said monitoring assemblies, the level distance between ends of said first sewer pipe, and the cross sectional area of said first sewer pipe for providing a second flow value, and

selection control means responsive to the diameter of said first sewer pipe and liquid pressure at an exit end of said first sewer pipe for providing a first control output when said pipe is full and a second control output when it is not; and

switching means responsive to said first and second flow values, and comprising means responsive to said first control output for supplying said first flow value to said computation means, and responsive to said second control output for supplying said second flow value to said computation means.

3. A system of measurement of flow gains in a first sewer pipeline having an entrance end connected from a first manhole, and said first sewer pipeline having a first pipe having an exit end connected to a second manhole, and wherein there is a second sewer pipeline having a second pipe having an exit pipe supplying flow to said first manhole comprising:

a first liquid height sensing means positioned a distance back into said first pipe at least 0.8 times the diameter of said first pipe for providing an output signal representative of liquid height in this pipe;

a second liquid height sensing element positioned in said second pipe a distance from the exit end of said second pipe at least equal to 0.8 times the diameter of said second pipe for providing an output signal representative of liquid height in this pipe;

sampling and recording means for periodically and synchronously, as between said first and second liquid height sensing means, and responsive to said outputs signals from said sensing means for sampling and recording said signals periodically over a selected period of time;

conversion means responsive to values of selected recorded signals for converting said values into liquid flow rates; and

computation means responsive to said conversion means and dry and rainy day samples of values from each of said liquid height sensing means for (1) determining the difference between like timed dry and rainy day flows at an exit end of said first pipe, (2) determining the difference between like timed dry and rainy day flows at the exit end of said second pipe, and (3) determining differences in said difference flows contained in (1) and (2) of this paragraph.

4. A measurement system as set forth in claim 3 wherein:

said conversion means comprises;

first liquid height-to-flow conversion means responsive to a liquid height value from said first liquid height sensing means, the radius of said first pipe, and the slope of said first pipe for determining a first flow value,

second liquid height-to-flow conversion means responsive to height values from both said first and second liquid height sensing means, the level distance between manholes, and the cross sectional area of said first sewer pipe for providing a second flow value, and

selection control means responsive to the diameter of said first sewer pipe and liquid height at an exit end of said first pipe for providing a first control output when said pipe is full, and a second control output when it is not; and

switching means for receiving said first and second flow values comprising means responsive to said first control output for supplying said first value to said computation means, and responsive to said second control output for supplying said second value to said computation means.

5. A measurement system as set forth in claim 4 including control means for selectively fetching samples from said sampling and recording means and placing the same in said conversion means, and whereby readings and computations may be made at selected times, and thereby measurements made during rainfalls being representative of inflow into said pipe, and measurements made following rainfalls representative of infiltration into said pipe.