Monitoring method for monitoring the operation of a dosing pump and dosing pump system
A monitoring method and dosing pump system monitor operation of a dosing pump including a dosing chamber ( 2 ), a displacement element ( 4 ) and an electric drive ( 12 ). A position (S) of the displacement element and a pressure (P) inside the dosing chamber are continuously recorded as a curve in a pressure-stroke diagram. The method includes monitoring at least one characteristic portion ( 36, 38, 40, 42 , B, C) of the curve in the pressure-stroke diagram by detecting a possible shift (A) of the characteristic portion over several strokes. The method further includes one or both of: adjusting a control of the electric drive based on the detected shift; and determining a trend of the shift over several strokes of the displacement element and determining based on the trend whether and/or when the shift will reach a predefined limit. A dosing pump system with the dosing pump execute the method.
1 . A monitoring method for monitoring operation of a dosing pump comprising a dosing chamber with at least one displacement element and an electric drive, a controller connected to the electric drive, wherein a pressure indicating sensor and a position sensor are connected to the controller, the method comprising the steps of:
detecting a position of the displacement element with the position sensor, and a pressure inside the dosing chamber or a pressure related indicator with the pressure indicating sensor, and recording the position, and the pressure or the pressure related indicator as a curve in a pressure-stroke diagram;
monitoring at least one characteristic portion of said curve in said pressure-stroke diagram with the controller and detecting a shift of the at least one characteristic portion by comparing said characteristic portion of said curve of the pressure-stroke diagram over several strokes of the displacement element with the controller; and
using the controller for determining a trend of the detected shift of the of the at least one characteristic portion over several strokes of the displacement element and determining based on the determined trend whether the detected shift of the least one characteristic portion will reach a predefined limit and when the detected shift of the at least one characteristic portion will reach the predefined limit in the future and based on the determination of when the detected shift of the least one characteristic portion will reach the predefined limit calculating a predicted time period until failure; and using the controller for at least one of:
outputting, to a communication device and/or display device, the calculated predicted time period until failure and/or outputting, to the communication device and/or display device a warning based on the predicted time period until failure;
adjusting a control of the electric drive prior to reaching the predefined limit at the calculated predicted time period; and
switching off the dosing pump prior to reaching the predefined limit at the calculated predicted time period.
2 . The monitoring method according to claim 1 , the calculated predicted time period until failure and/or a warning based on the predicted time period until failure is output to the communication device, the display device and/or a control device.
3 . The monitoring method according to claim 1 , wherein the trend is determined based on an average speed of the shift of the at least one characteristic portion.
4 . The monitoring method according to claim 1 , wherein the predicted time period, based on when the shift of the at least one characteristic portion will reach the predefined limit, is calculated by an extrapolation based on the trend.
5 . The monitoring method according to claim 1 , wherein the predicted time period, based on when the shift of the at least one characteristic portion will reach the predefined limit, is calculated based on a remaining interval between a last recorded value of the at least one characteristic portion or an average of last recorded values of the at least one characteristic portion and said predefined limit.
6 . The monitoring method according to claim 1 , wherein said at least one characteristic portion is defined by at least one characteristic point of the curve.
7 . The monitoring method according to claim 1 , wherein said at least one characteristic portion is one or more of: a section of the curve; a turning point or turning portion of the curve; an inflexion point or inflexion portion of the curve; and a saddle point or saddle portion of the curve.
8 . The monitoring method according to claim 1 , wherein the at least one characteristic portion is one or more of: an indicator for cavitation; an indicator of air inside the dosing chamber; an indicator of overpressure; an indicator of leakage; an indicator of valve leakage; an indicator of clogging of a flow path; an indicator of malfunction of a pulsation damper; and an indicator of a line burst.
9 . The monitoring method according to claim 1 , wherein the at least one characteristic portion of the curve is one or more of: in a section of the curve representing a suction stroke of the displacement element; in a section of the curve representing a pressure stroke of the displacement element; in a section of the curve representing an expansion phase; in a section of the curve representing a phase of pressure buildup; and in at least one transition section between said sections of the curve.
10 . The monitoring method according to claim 1 , wherein the calculation of the predicted time period, based on when the shift of the at least one characteristic portion will reach a predefined limit, is continuously or periodically updated.
11 . The monitoring method according to claim 1 , wherein the control of the electric drive is adjusted by changing a stroke pattern to compensate for a malfunction causing the detected shift of the at least one characteristic portion, to reduce the detected shift at least partly or to decelerate a future shift.
12 . The monitoring method according to claim 1 , wherein
the pressure indicating sensor is operatively connected to the controller and is configured to detect the pressure inside the dosing chamber or the pressure related indicator;
the the pressure indicating sensor comprising:
a force sensor connected to the controller such that the controller receives one or more of force values representing pressure inside the dosing chamber from said force sensor; or
a pressure sensor connected to the controller such that the controller receives one or more of pressure values representing pressure inside the dosing chamber from said pressure sensor; or
an electric drive signal connection from the electric drive to the controller to provide data representing pressure inside the dosing chamber,
wherein the controller:
generates the output of the calculated predicted time period as the predicted time period until failure; and
generates the output of the warning; and
controls the electric drive prior to reaching the predefined limit at the calculated time period; and
switches off the dosing pump prior to reaching the predefined limit at the calculated predicted time period.
13 . A dosing pump system comprising:
a dosing pump, the dosing pump comprising:
a dosing chamber;
at least one movable displacement element associated with the dosing chamber; and
an electric drive connected to said displacement element for moving the displacement element; and
a controller connected to a pressure indicating sensor and a position sensor, the controller, the pressure indicating sensor, and the position sensor are configured to:
continuously record a position of the displacement element and at least one of a pressure inside the dosing chamber and a pressure related indicator as a curve in a pressure-stroke diagram with the controller;
monitor at least one characteristic portion of said curve in said pressure-stroke diagram with the controller;
detect a shift of the at least one characteristic portion by comparing said characteristic portion of said curve of the pressure-stroke diagram over several strokes of the displacement element using the controller; and
determine a trend of the detected shift of the at least one characteristic portion and based on the determined trend determine whether the detected shift of the least one characteristic portion will reach a predefined limit and when the detected shift of the at least one characteristic portion will reach the predefined limit in the future and based on the determination of when the detected shift of the least one characteristic portion will reach the predefined limit calculating a predicted time period until failure with the controller; and using the controller for at least one of:
outputting, to a communication device and/or display device, the predicted time period until failure and/or outputting, to the communication device and/or display device, a warning based on the predicted time period until failure;
adjusting a control of the electric drive prior to reaching the predefined limit at the calculated time predicted period; and
switching off the dosing pump prior to reaching the predefined limit at the calculated predicted time period.
14 . The dosing pump system according to claim 13 , further comprising at least one of the display device being connected to the controller and the communication device forming a part of the controller or being connected to the controller, wherein the controller is configured to:
output the calculated predicted time period via the at least one of the display device and the communication device.
15 . The dosing pump system according to claim 13 , wherein the controller and the dosing pump are integrated into a dosing pump unit or the controller is arranged at a distance from the dosing pump and connected to the dosing pump via a data connection.
16 . The dosing pump system according to claim 13 , wherein:
the dosing pump comprises the pressure indicating sensor; and the pressure indicating sensor is at least one of a force sensor and a pressure sensor connected to the controller such that the controller receives one or more of force values and pressure values representing pressure inside the dosing chamber from said at least one of a force sensor and a pressure sensor; or
the controller is connected to the electric drive to receive data representing pressure inside the dosing chamber from said electric drive.
17 . The dosing pump system according to claim 13 , wherein the controller is configured such that a stroke pattern of the displacement element is changed to compensate a malfunction causing the detected shift of the at least one characteristic portion and to reduce the shift at least partly.
18 . A dosing pump system comprising:
a dosing pump, the dosing pump comprising:
a dosing chamber;
at least one movable displacement element associated with the dosing chamber; and
an electric drive connected to said displacement element for moving the displacement element;
a control device operatively connected to the electric drive; and
detecting means to detect a pressure inside the dosing chamber or a pressure related indicator, the detecting means being operatively connected to the control device and comprising:
a force sensor connected to the control device such that the control device receives one or more of force values representing the pressure inside the dosing chamber from said force sensor; or
a pressure sensor connected to the control device such that the control device receives one or more of pressure values representing the pressure inside the dosing chamber from said pressure sensor; or
an electric drive signal connection from the electric drive to the control device to provide data representing the pressure inside the dosing chamber,
wherein the control device includes a CPU, memory, software, a pressure sensor, and a position sensor, and the control device is configured to:
continuously record a position of the displacement element and at least one of the pressure inside the dosing chamber and the pressure related indicator as a curve in a pressure-stroke diagram;
monitor at least one characteristic portion of said curve in said pressure-stroke diagram to detect a shift of the at least one characteristic portion by comparing said characteristic portion of said curve of the pressure-stroke diagram over several strokes of the displacement element;
adjust a control of the electric drive based on the detected shift of the at least one characteristic portion; and
determine a trend of the detected shift of the at least one characteristic portion and based on the determined trend determine whether the detected shift of the least one characteristic portion will reach a predefined limit and when a shift of the at least one characteristic portion will reach the predefined limit in the future;
calculate a predicted time period until failure based on the determination of when the detected shift of the least one characteristic portion will reach the predefined limit and at least one of:
output the calculated predicted time period until failure and/or output a warning; and
switch off the dosing pump prior to reaching the predefined limit at the calculated predicted time period.
19 . The dosing pump system according to claim 18 , further comprising at least one of a display device connected to the control device and a communication device forming a part of the control device or connected to the control device, wherein the control device is configured to output the calculated predicted time period via the at least one of the display device and the communication device.
20 . The dosing pump system according to claim 18 , wherein the control device is configured to adjust a control of the electric drive based on the detected shift of the at least one characteristic portion such that a stroke pattern of the displacement element is changed to compensate a malfunction causing the detected shift of the at least one characteristic portion and to reduce the shift at least partly.