# US 2010/0166569 A1 · Sewage pump blockage detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166569 A1 - Document ID: US20100166569A1 - Status: Published application - Kind: A1 - Application number: 12/593,912 - Filed: 2008-03-18 - Published: 2010-07-01 - Earliest claimed: 2007-03-29 - Assignees: Retroflo Limited - Inventors: Laundon Andy - Web page: https://patentgrep.com/patent/US20100166569A1 ## CPC - F04D 15/0209: {responsive to a condition of the working fluid (F04D15/029 takes precedence)} - F04D 15/0066: {by changing the speed, e.g. of the driving engine} - F04D 15/0088: {Testing machines} - F04D 15/0236: {Lack of liquid level being detected by analysing the parameters of the electric drive, e.g. current or power consumption} - F04D 15/0281: {responsive to a condition not otherwise provided for} - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) ## Abstract A method of monitoring a pump which operates to pump sewage from a wet well in which the current drawn by the pump is detected along with the speed of operation of the pump and the wet well level. The detected values are compared with stored values in a look up table to determine whether the pump is blocked. ## Claims ### Claim 1 A method of monitoring a pump operable to pump sewage from a wet well comprising the steps of: detecting the current drawn by the pump; detecting the speed of operation of the pump; detecting the wet well level; and comparing each of the detected values with stored values in a look up table to determine whether the pump is blocked. ### Claim 2 (canceled) ### Claim 3 (depends on 1) A method as claimed in claim 1 wherein the look up table is a look up table adapted to conform to the characteristics of a particular pumping station. ### Claim 4 A method as claimed in any preceding claim wherein the look up table comprises upper and/or lower threshold values for each parameter and wherein in order to determine that the pump is blocked, any two out of the three parameters or all three parameters may need to fall outside said threshold levels. ### Claim 5 (canceled) ### Claim 6 (depends on 4) A method as claimed in claim 4 wherein the look up table also comprises upper and/or lower super threshold levels wherein if the value of any one parameter falls outside the upper or lower super threshold, the pump is determined to be blocked. ### Claim 7 (depends on 6) A method as claimed in claim 6 wherein threshold levels and super threshold levels for one parameter depend on the detected value of another parameter. ### Claim 8 (depends on 1) A method as claimed in claim 1 wherein the method includes the step of determining a rate of change of any or all of: the current drawn by the pump; the speed of operation of the pump; and the wet well level and wherein the look up table comprises threshold levels and/or super threshold levels for the rates of change. ### Claim 9 (canceled) ### Claim 10 (canceled) ### Claim 11 (depends on 8) A method as claimed in claim 8 wherein to determine that the pump is blocked requires that two of the three or all three rates of change fall outside the the range defined by the lower and upper threshold levels or that at least one rate of change falls outside the super threshold levels. ### Claim 12 (depends on 11) A method as claimed in claim 11 wherein the or each threshold level and/or super threshold level is dependent on the determined rate of change of a different parameter. ### Claim 13 (depends on 1) A method as claimed in claim 1 wherein in response to a determination that the pump is blocked, a self cleaning procedure is initiated. ### Claim 14 (depends on 13) A method as claimed in claim 13 wherein the self cleaning procedure includes reversing the operating direction of the pump whereby the pump is run in reverese at a first specified speed for a first specified time interval, then forward at a second specified speed for a second specified time interval, this procedure being repeated three times. ### Claim 15 (canceled) ### Claim 16 (depends on 14) A method as claimed in claim 14 wherein if, upon resumption of normal operation it is determined that the pump is still blocked, an alarm is output. ### Claim 17 (depends on 1) A method as claimed in claim 1 wherein the method includes the step of storing current, pump speed and wet well level values for future reference; and/or the step of storing details of occasions upon which the self cleaning procedure was initiated and/or occasions upon which alarms are output. ### Claim 18 (canceled) ### Claim 19 A control unit for a pump operable to pump sewage from a wet well, the control unit comprising: current detection means; pump speed detection means; wet well level detection means; memory means operable to store a look up table of current, pump speed and wet well level values; and a processor operable to compare each of the detected current, speed and level values with values stored in the look up table to determine whether the pump is blocked. ### Claim 20 (depends on 19) A control unit as claimed in claim 19 wherein the control unit is operable in accordance with the method comprising the steps of: detecting the current drawn by the pump; detecting the speed of operation of the pump; detecting the wet well level; and comparing each of the detected values with stored values in a look up table to determine whether the pump is blocked. ### Claim 21 (depends on 20) A control unit as claimed in claim 20 wherein the processor is operable to determine a rate of change of any or all of: the current drawn by the pump; the speed of operation of the pump; and the wet well level and is further operable to compare the determined rate of change values with rate of change values stored in the look up table to determine whether the pump is blocked. ### Claim 22 (canceled) ### Claim 23 (depends on 21) A control unit as claimed in claim 21 wherein the control unit is operable to initiate a self cleaning procedure if it is determined that the pump is blocked and wherein if it is determined that the pump is still blocked after the self cleaning procedure, the processor is operable to output an alarm signal. ### Claim 24 (canceled) ### Claim 25 (depends on 23) A control unit as claimed in claim 23 wherein the alarm signal is received by an alarm means, and wherein the alarm is either: an integral alarm means, or an external unit with a suitable connection to the control unit. ### Claim 26 (canceled) ### Claim 27 (canceled) ### Claim 28 (canceled) ### Claim 29 (depends on 25) A control unit as claimed in claim 25 wherein the memory means is operable to store current, pump speed and wet well level values for future reference and/or store details of occasions upon which the self cleaning procedure was initiated and/or occasions upon which alarms are output. ### Claim 30 (canceled) ### Claim 31 (depends on 29) A control unit as claimed in claim 29 wherein the control unit is provided with a user interface and wherein the user interface is operable to enable the cancellation of an alarm, the output of an alarm, the initiation of the self cleaning procedure and the transmission of data stored in the memory means to an external unit. ### Claim 32 (canceled) ### Claim 33 A pump operable in accordance with a method comprising the steps of detecting the current drawn by the pump; detecting the speed of operation of the pump; detecting the wet well level; and comparing each of the detected values with stored values in a look up table to determine whether the pump is blocked. ### Claim 34 A pump incorporating a control unit comprising: current detection means; pump speed detection means; wet well level detection means; memory means operable to store a look up table of current, pump speed and wet well level values; and a processor operable to compare each of the detected current, speed and level values with values stored in the look up table to determine whether the pump is blocked. ### Claim 35 A sewage pumping station incorporating a pump operable in accordance with a method comprising the steps of detecting the current drawn by the pump; detecting the speed of operation of the pump; detecting the wet well level; and comparing each of the detected values with stored values in a look up table to determine whether the pump is blocked. ### Claim 36 A sewage network incorporating one or more pumping stations incorporating a pump operable in accordance with a method comprising the steps of detecting the current drawn by the pump; detecting the speed of operation of the pump; detecting the wet well level; and comparing each of the detected values with stored values in a look up table to determine whether the pump is blocked.