Method of controlling a water reservoir supply pump arrangement and water reservoir supply pump arrangement

Patent metadata

Field	Value
Publication number	US-11060266-B2
Application number	US-201715820964-A
Country	US
Kind code	B2
Filing date	Nov 22, 2017
Priority date	Nov 25, 2016
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

A method of controlling a water reservoir supply pump arrangement determines a set value p, q, v, n of the pump arrangement based on an offset value p ref , q ref , n ref , v ref , G 0 reduced by a component which is a function of a difference between an actual water level h and a predetermined water level h ref in a water reservoir. The difference is weighted by a proportional gain factor G. Further, a water reservoir supply pump arrangement is provided including at least one water pump and a control device for controlling the at least one pump.

First claim

What is claimed is:

1. A method of controlling a water reservoir supply pump arrangement, the method comprising the steps of:
determining a set value of the pump arrangement based on an offset value reduced by a component which is a function of a difference between an actual water level and a predetermined water level in a water reservoir;
weighting the difference by an automatically adjusted proportional gain factor; and
adjusting the gain factor each time a predetermined water level in the reservoir is reached or a predetermined time interval has elapsed or both each time a predetermined water level in the reservoir is reached and a predetermined time interval has elapsed, wherein the gain factor or the offset value or both the gain factor and the offset value are adjusted such that the maximum water level measured over time is a fraction of a difference between a maximum and a minimum permissible water level, wherein the actual water level is controlled based on one or more of the gain factor and the offset value such that the actual water level varies in the water reservoir and water is exchanged in the water reservoir to maintain water quality in the water reservoir, wherein the gain factor (G) is adjusted each time after the predetermined time interval has elapsed such that
G k+1 =G k −K ( h high *−h high )
where
h high *=αh max +(1−α) h min

and where k denotes the k th time interval T, α denotes the fraction, h max denotes a maximum permissible level threshold, h min denotes a minimum permissible level threshold, h high is the maximum measured level over a given period of time, and K being a predetermined constant>0.

2. The method according to claim 1 , wherein the set value and the offset value are one of pump reference pressure, reference pump flow, reference pump speed, reference number of switched-on pumps in the water reservoir supply pump arrangement.

3. The method according to claim 1 , wherein the predetermined water level is a minimum water level, the actual water level is controlled via a proportional controller.

4. The method according to claim 1 , wherein the water level, when the gain factor is adjusted, is the maximum water level in the reservoir.

5. The method according to claim 1 , wherein the water reservoir supply pump arrangement is switched on when the actual water level is below a predetermined minimum level and is switched off when the actual water level has reached a predetermined maximum water level.

6. The method according to claim 1 , wherein the set value is flow, and a maximum set flow is decreased by a predetermined flow value if the pressure is higher than a predetermined maximum pressure value, and a minimum set flow is increased by a predetermined flow value as long as the pressure is lower than a predetermined minimum pressure value.

7. The method according to claim 1 , wherein the set value is pressure, and a maximum set pressure is decreased by a predetermined pressure value if the flow is higher than a predetermined maximum flow value, and a minimum set pressure is increased by a predetermined pressure value if the flow is lower than a predetermined minimum flow value.

8. The method according to claim 1 , wherein the gain and the offset value are adjusted such that variations of the water level over the time utilize a predefined water level band, where the water level band lies between a maximum and a minimum permissible water level.

9. The method according to claim 1 , wherein the set value is one of pressure and flow, and the offset value is gain, and wherein the proportional gain factor and the offset value are adjusted each time the predetermined interval has lapsed, the proportional gain factor and the offset value being adjusted as
G 1,k+1 =G 1,k −K 1 (( h high *−h high )−( h low *−h low ))

G 0,k+1 =G 0,k +K 0 (( h high *−h high )+( h low *−h low ))

with
G 1, k+1 being the set value adjusted after the (k+1) th time interval,
G 1, k being the set value adjusted after the k th time interval,
G 0, k+1 being the offset value adjusted after the (k+1) th time interval,
G 0, k being the offset value adjusted after the k th time interval,
and
h high being the maximum level of the k th time interval,
h low being the minimum level of the k th time interval,

and
h high *=αh max +(1−α) h min

h low *=(1−β) h max +βh min

where k denotes the k th said time period and α denotes the fraction, β denotes another fraction, h max denotes a maximum permissible level threshold, h min denotes a minimum permissible level threshold, h high is the maximum level over a given period of time, h low is the minimum level over a given period of time and K 0 and K 1 being predetermined constants>0.

10. The method according to claim 1 , wherein the set value is one of pressure and flow, and the offset value is gain, and wherein the proportional gain factor and the offset value are adjusted each time a predetermined interval has elapsed, the proportional gain factor and the offset value being adjusted as
G 1,k+1 =G 1,k −K 1 (( h high *−h high )−( h low *−h low ))

G 0,k+1 =G 0,k +K 0 G 1,k+1 (( h high *−h high )+( h low *−h low ))

with
G 1, k+1 being the set value adjusted after the (k+1) th time interval,
G 1, k being the set value adjusted after the k th time interval,
G 0, k+1 being the offset value adjusted after the (k+1) th time interval,
G 0, k being the offset value adjusted after the k th time interval,
and
h high being the maximum level of the k th time interval,
h low being the minimum level of the k th time interval,

and
h high *=αh max +(1−α) h min

h low *=(1−β) h max +βh min

where k denotes the k th said time period, α denotes the fraction, β denotes another fraction, h max denotes a maximum level threshold, h min denotes a minimum level threshold, h high is the maximum level over a given period of time, h low is the minimum level over a given period of time and K 0 and K 1 being predetermined constants>0.

11. The method according to claim 1 , wherein the set value is one of pressure and flow, and the offset value is gain, and wherein the offset value is updated each time the predetermined interval has elapsed and if the water level has dropped below the minimum permissible level (h min ), the offset value being adjusted as

G

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Assignees

• Grundfos Holding As

Inventors

• Kallesøe Carsten
• Hassan Abdul-Sattar

Classifications

• E03B1/00

  Methods or layout of installations for water supply (E03B3/00, E03B9/00 take precedence) · CPC title

• F04D15/00 Primary

  Control, e.g. regulation, of pumps, pumping installations or systems · CPC title

• F04D15/0066

  by changing the speed, e.g. of the driving engine · CPC title

• E03B11/10

  for public or like main water supply · CPC title

• E03B11/12

  of high-level tanks · CPC title