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US4108574A
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Apparatus and method for the indirect measurement and control of the flow rate of a liquid in a piping system
Assignee: International Paper Co
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Filing: 1977-01-21
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Granted: 1978-08-22
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Expires: 1997-01-21
Abstract
Abstract Apparatus and process for automatically measuring and controlling the instantaneous flow rate of a liquid in a piping system by varying the speed of a centrifugal pump in response to a flow rate signal determined indirectly by sampling two flow-related parameters associated with the pump and pump motor and then converting in an on-line computer the two measurements to the corresponding unique flow rate value by the use of previously determined mathematical relationships stored in the computer. The mathematical relationships are derived from data correlating flow rate with the two flow-related variables, which data is taken with a flow meter and control valve temporarily installed in the piping system during the "shake-down" testing of the piping system. A third flow-related variable is sampled, a pair of flow rate values determined, and an alarm activated in response to the difference between the values to provide the additional feature of pump mechanical performance monitoring. A viscosity-related property of the fluid also is determined indirectly by the use of a mathematical relationship whenever three flow-related variables are monitored, the mathematical relationships having been derived from data taken by running fluids of different but known values of the viscosity-related property through the piping system during the "shake-down" testing.
Inventors
- 👤 Thomas S. Bartley
- 👤 Quinlan T. Rosenblath, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:59
CPC Classifications
G; G05; G05D; G05D7/00; G05D7/06; G05D7/0617; G05D7/0629; G05D7/0676; G01; G01F; G01F1/00
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
204 words
Apparatus for continuously controlling the rate of flow of a liquid in a piping system in agreement with a desired flow rate, the apparatus comprising: (a) a centrifugal pump; (b) means for driving said pump, said driving means having a continuously variable speed capability; (c) means for indirectly and continuously measuring the instantaneous rate of flow of the liquid in the piping system, said indirect measuring means including (A) means for sensing at least two flow-related variables, said flow-related variables being associated with said pump and said driving means, said sensing means also including means for generating and transmitting signals representative of the instantaneous value of each of the sensed variables; (B) calculating means including (i) memory means containing stored therein a set of mathematical relationships relating flow rate to said two flow-related variables, (ii) converter means for receiving the transmitted signals and transforming the signals into a first converted signal representative of flow rate by use of the stored mathematical relationships, and (iii) means for comparing a reference signal representing the desired flow rate with said first converted signal and for determining the error therebetween; and (d) control means responsive to said error varying smoothly the speed of said variable speed drive means.
Claim 2
Dependent Claim
204 words
Apparatus for continuously controlling the rate of flow of a liquid in a piping system in agreement with a desired flow rate, the apparatus comprising: (a) a centrifugal pump; (b) means for driving said pump, said driving means having a continuously variable speed capability; (c) means for indirectly and continuously measuring the instantaneous rate of flow of the liquid in the piping system, said indirect measuring means including (A) means for sensing at least two flow-related variables, said flow-related variables being associated with said pump and said driving means, said sensing means also including means for generating and transmitting signals representative of the instantaneous value of each of the sensed variables; (B) calculating means including (i) memory means containing stored therein a set of mathematical relationships relating flow rate to said two flow-related variables, (ii) converter means for receiving the transmitted signals and transforming the signals into a first converted signal representative of flow rate by use of the stored mathematical relationships, and (iii) means for comparing a reference signal representing the desired flow rate with said first converted signal and for determining the error therebetween; and (d) control means responsive to said error varying smoothly the speed of said variable speed drive means.
Claim 3
Dependent Claim
26 words
The flow rate control apparatus of claim 1 in which said sensing means includes means for sensing the power used by said variable speed drive means.
Claim 4
Dependent Claim
49 words
The flow rate control apparatus of claim 1 in which said calculating means is digital and wherein all of said signals generated and transmitted by said sensing means and received by said calculating means are pulse trains having frequencies proportional to the instantaneous values of the respective represented variables.
Claim 5
Dependent Claim
15 words
The flow control apparatus of claim 1 wherein said variable speed drive means is electric.
Claim 6
Dependent Claim
38 words
The flow control apparatus of claim 4 wherein said variable speed drive means includes a frequency controlled AC electric motor and an AC electric motor power supply capable of providing excitation continuously over a range of electric frequencies.
Claim 7
Dependent Claim
24 words
The flow rate control apparatus of claim 1 in which said sensing means includes means for measuring the pressure rise developed by said pump.
Claim 8
Dependent Claim
33 words
The flow rate control apparatus of claim 6 in which said pressure rise sensing means includes a pressure-sensing means located upstream of said pump and a pressure-sensing means located downstream of said pump.
Claim 9
Dependent Claim
23 words
The flow rate control apparatus of claim 6 in which said sensing means also includes means for measuring the speed of said pump.
Claim 10
Dependent Claim
27 words
The flow rate control apparatus of claim 6 in which said sensing means also includes means for sensing the power used by said variable speed drive means.
Claim 11
Dependent Claim
21 words
The flow rate control apparatus of claim 1 in which said sensing means includes means for measuring speed of the pump.
Claim 12
Dependent Claim
27 words
The flow rate control apparatus of claim 10 in which said sensing means also includes means for sensing the power used by said variable speed drive means.
Claim 13
Dependent Claim
235 words
A process for continuously controlling the rate of flow of a given liquid in a piping system in agreement with a desired flow rate, the system having a centrifugal pump which functions as the prime mover, a smoothly variable speed drive means for driving the pump, the process comprising the steps of: (a) obtaining a set of data correlating the flow rate of a given liquid through the centrifugal pump with two flow-related variables: (b) developing a set of mathematical relationships relating flow rate to said flow-related variables using said data and storing said set of equations in a calculating means; (c) operating the system in a normal mode; (d) indirectly and continuously measuring the instantaneous rate of flow of the liquid in the piping system, said measuring step including the steps of (i) sensing said two flow-related variables and generating and transmitting to said calculating means signals representative of said two flow-related variables with the piping system operating in said normal mode; (ii) converting in said calculating means said signals representing said two flow-related variables to a first converted signal representative of flow rate through use of said stored set of mathematical relationships, (e) comparing the first converted signal representative of the flow rate with a reference signal that represents the desired flow rate and determining the difference therebetween; and (f) smoothly varying the rotational speed of the pump in response to said difference.
Claim 14
Dependent Claim
235 words
A process for continuously controlling the rate of flow of a given liquid in a piping system in agreement with a desired flow rate, the system having a centrifugal pump which functions as the prime mover, a smoothly variable speed drive means for driving the pump, the process comprising the steps of: (a) obtaining a set of data correlating the flow rate of a given liquid through the centrifugal pump with two flow-related variables: (b) developing a set of mathematical relationships relating flow rate to said flow-related variables using said data and storing said set of equations in a calculating means; (c) operating the system in a normal mode; (d) indirectly and continuously measuring the instantaneous rate of flow of the liquid in the piping system, said measuring step including the steps of (i) sensing said two flow-related variables and generating and transmitting to said calculating means signals representative of said two flow-related variables with the piping system operating in said normal mode; (ii) converting in said calculating means said signals representing said two flow-related variables to a first converted signal representative of flow rate through use of said stored set of mathematical relationships, (e) comparing the first converted signal representative of the flow rate with a reference signal that represents the desired flow rate and determining the difference therebetween; and (f) smoothly varying the rotational speed of the pump in response to said difference.
Claim 15
Dependent Claim
89 words
The process as in claim 12 wherein the step of obtaining a set of data correlating the flow rate of a given liquid through the centrifugal pump with two flow-related variables includes (i) temporarily installing a flow meter and throttling valve downstream of the pump, (ii) operating the pump over an expected range of flow rate values and system flow resistances by varying the speed of the pump and the opening of the control valve, and (iii) recording simultaneous values of the flow rate and said two flow-related variables.
Claim 16
Dependent Claim
17 words
The process as in claim 12 wherein one of said two flow-related variables is pump drive power.
Claim 17
Dependent Claim
16 words
The process of claim 12 wherein one of said two flow-related variables is pump pressure rise.
Claim 18
Dependent Claim
17 words
The process as in claim 15 wherein the other of said two flow-related variables is pump speed.
Claim 19
Dependent Claim
18 words
The process as in claim 15 wherein the other of said two flow-related variables is pump drive power.
Claim 20
Dependent Claim
16 words
The process as in claim 12 wherein one of said two flow-related variables is pump speed.
Claim 21
Dependent Claim
18 words
The process as in claim 18 wherein the other of said two flow-related variables is pump drive power.
Claim 22
Dependent Claim
209 words
Apparatus for monitoring mechanical performance of a centrifugal pump in a piping system that includes the pump coupled with a variable speed pump drive means as the prime mover for the liquid flowing therein, the apparatus comprising: (a) means for continuously providing two separate indirect measurements of the instantaneous system flow rate, said means including (A) means for sensing three flow-related variables including pump pressure rise and at least two other flow-related variables associated with said pump and said drive means, said sensing means also including means for generating and transmitting signals representative of the instantaneous value of each of the sensed variables; (B) calculating means including (i) memory means containing stored therein two sets of mathematical relationships each relating flow rate to two of the said three flow-related variables wherein the pump pressure rise variable is used in one and only one of said two relationship sets; (ii) converter means for receiving the transmitted signals and transforming the signals into a first converted signal and a second converted signal both representative of flow rate by use of the stored mathematical relationships, and (iii) means for comparing said first and second converted signals for determining the difference therebetween; and (b) means responsive to said difference for actuating an alarm.
Claim 23
Dependent Claim
209 words
Apparatus for monitoring mechanical performance of a centrifugal pump in a piping system that includes the pump coupled with a variable speed pump drive means as the prime mover for the liquid flowing therein, the apparatus comprising: (a) means for continuously providing two separate indirect measurements of the instantaneous system flow rate, said means including (A) means for sensing three flow-related variables including pump pressure rise and at least two other flow-related variables associated with said pump and said drive means, said sensing means also including means for generating and transmitting signals representative of the instantaneous value of each of the sensed variables; (B) calculating means including (i) memory means containing stored therein two sets of mathematical relationships each relating flow rate to two of the said three flow-related variables wherein the pump pressure rise variable is used in one and only one of said two relationship sets; (ii) converter means for receiving the transmitted signals and transforming the signals into a first converted signal and a second converted signal both representative of flow rate by use of the stored mathematical relationships, and (iii) means for comparing said first and second converted signals for determining the difference therebetween; and (b) means responsive to said difference for actuating an alarm.
Claim 24
Dependent Claim
42 words
The flow rate control apparatus of claim 20 wherein said calculating means is digital and each of said three signals and each of said two converted signals is a pulse train having a frequency proportional to the value of the represented variable.
Claim 25
Dependent Claim
21 words
The flow rate control apparatus of claim 20 wherein the two other flow-related variables are pump speed and pump drive power.
Claim 26
Dependent Claim
252 words
A process for continuously monitoring the mechanical performance of a centrifugal pump installed in a piping system, said pump being coupled with a variable speed drive means and being the prime mover for liquid flowing therein, the process comprising the steps of: (a) obtaining two sets of data, each set correlating the flow rate of the liquid through the centrifugal pump with two of at least three flow-related variables, said at least three flow-related variables including pump pressure rise wherein the pump pressure rise variable appears in one and only one of said two data sets; (b) developing two sets of mathematical relationships each relating flow rate to two flow-related variables using said data sets and storing said sets of mathematical relationships in a calculating means; (c) operating the system in a normal mode; (d) continuously providing two separate indirect measurements of the instantaneous system flow rate, said providing step including the steps of (i) sensing pump pressure rise and said two other flow-related variables and generating and transmitting to said calculating means signals representative of said three flow-related variables with the piping system operating in said normal mode; (ii) converting in said calculating means said signals representing said three flow-related variables to first and second converted signals each representative of flow rate through use of said stored sets of mathematical relationships; (e) comparing in said calculating means said first converted signal with said second converted signal and determining a difference therebetween; and (f) actuating an alarm in response to said difference.
Claim 27
Dependent Claim
252 words
A process for continuously monitoring the mechanical performance of a centrifugal pump installed in a piping system, said pump being coupled with a variable speed drive means and being the prime mover for liquid flowing therein, the process comprising the steps of: (a) obtaining two sets of data, each set correlating the flow rate of the liquid through the centrifugal pump with two of at least three flow-related variables, said at least three flow-related variables including pump pressure rise wherein the pump pressure rise variable appears in one and only one of said two data sets; (b) developing two sets of mathematical relationships each relating flow rate to two flow-related variables using said data sets and storing said sets of mathematical relationships in a calculating means; (c) operating the system in a normal mode; (d) continuously providing two separate indirect measurements of the instantaneous system flow rate, said providing step including the steps of (i) sensing pump pressure rise and said two other flow-related variables and generating and transmitting to said calculating means signals representative of said three flow-related variables with the piping system operating in said normal mode; (ii) converting in said calculating means said signals representing said three flow-related variables to first and second converted signals each representative of flow rate through use of said stored sets of mathematical relationships; (e) comparing in said calculating means said first converted signal with said second converted signal and determining a difference therebetween; and (f) actuating an alarm in response to said difference.
Claim 28
Dependent Claim
116 words
The process as in claim 23 wherein the step of obtaining two sets of data, each set correlating the flow rate of the liquid through the centrifugal pump with two of said three flow-related variables wherein the pump pressure rise variable appears in only one of said two data sets, includes (i) temporarily installing a flow meter and throttling valve downstream of the pump, (ii) operating the pump over an expected range of flow rate values and system flow resistances by varying the speed of the pump and the opening of the control valve, and (iii) recording, for each data set, simultaneous values of the flow rate and the corresponding two of said three flow-related variables.
Claim 29
Dependent Claim
36 words
The process for monitoring the performance of a centrifugal pump as in claim 23 wherein said two other flow-related variables associated with the pump and the pump drive means are pump speed and pump drive power.
Claim 30
Dependent Claim
144 words
Apparatus for continuously measuring a viscosity-related property of a liquid flowing at variable rates in a piping system that includes a centrifugal pump coupled with a variable speed pump drive means as the prime mover for the liquid, the apparatus comprising: (a) means for sensing at least three flow-related variables, said flow-related variables being associated with said pump and said drive means, said sensing means also including means for generating and transmitting signals representative of the instantaneous value of each of the sensed variables; (b) calculating means including (i) memory means containing stored therein a set of mathematical relationships relating the viscosity-related property to said three flow-related variables, (ii) converter means for receiving the transmitted signals and transforming the signals into a converted signal representative of the viscosity-related property by use of the stored mathematical relationships; and (c) means for displaying said converted signal.
Claim 31
Dependent Claim
144 words
Apparatus for continuously measuring a viscosity-related property of a liquid flowing at variable rates in a piping system that includes a centrifugal pump coupled with a variable speed pump drive means as the prime mover for the liquid, the apparatus comprising: (a) means for sensing at least three flow-related variables, said flow-related variables being associated with said pump and said drive means, said sensing means also including means for generating and transmitting signals representative of the instantaneous value of each of the sensed variables; (b) calculating means including (i) memory means containing stored therein a set of mathematical relationships relating the viscosity-related property to said three flow-related variables, (ii) converter means for receiving the transmitted signals and transforming the signals into a converted signal representative of the viscosity-related property by use of the stored mathematical relationships; and (c) means for displaying said converted signal.
Claim 32
Dependent Claim
24 words
The viscosity-related property measuring apparatus as in claim 26 wherein said three flow-related variables are pump speed, pump drive power, and pump pressure rise.
Claim 33
Dependent Claim
32 words
The viscosity-related property measuring apparatus as in claim 26 wherein said calculating means is digital and said signals are pulse trains having frequencies proportional to the values of the respective represented variable.
Claim 34
Dependent Claim
181 words
A process for determining the value of a viscosity-related property of a liquid flowing in a piping system, the system having a centrifugal pump which functions as the final control element, a variable speed drive means for driving the pump, and means for sensing three flow-related variables associated with the pump and the pump drive means, the process comprising the steps of: (a) obtaining a set of data correlating the viscosity-related property with the three flow-related variables; (b) developing a set of mathematical relationships relating the viscosity-related property to the three flow-related variables using said data and storing said set of mathematical relationships in a calculating means; (c) operating the system in a normal mode; (d) sensing said three flow-related variables and generating and transmitting to said calculating means signals representative of the three flow-related variables with the piping system operating in said normal mode; (e) converting in said calculating means said signals representing the three flow-related variables to a signal representative of the viscosity-related property through use of said stored set of mathematical relationships; and (f) displaying said converted signal.
Claim 35
Dependent Claim
181 words
A process for determining the value of a viscosity-related property of a liquid flowing in a piping system, the system having a centrifugal pump which functions as the final control element, a variable speed drive means for driving the pump, and means for sensing three flow-related variables associated with the pump and the pump drive means, the process comprising the steps of: (a) obtaining a set of data correlating the viscosity-related property with the three flow-related variables; (b) developing a set of mathematical relationships relating the viscosity-related property to the three flow-related variables using said data and storing said set of mathematical relationships in a calculating means; (c) operating the system in a normal mode; (d) sensing said three flow-related variables and generating and transmitting to said calculating means signals representative of the three flow-related variables with the piping system operating in said normal mode; (e) converting in said calculating means said signals representing the three flow-related variables to a signal representative of the viscosity-related property through use of said stored set of mathematical relationships; and (f) displaying said converted signal.
Claim 36
Dependent Claim
78 words
The process for measuring a viscosity-related property of a liquid as in claim 29 wherein the step of obtaining a set of data correlating the viscosity-related property with the three flow-related variables includes (i) temporarily installing a flow meter and throttling valve downstream of the pump, (ii) operating said pump in said system with fluids of different but known values of the viscosity-related property, and (iii) recording simultaneous values of the viscosity-related property and of said three variables.
Claim 37
Dependent Claim
38 words
The process for measuring a viscosity-related property of a liquid as in claim 29 wherein said three flow-related variables associated with said pump and said pump drive means are pump speed, pump drive power, and pump pressure rise.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-08-21 | 1982-02-20 | 1982-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-08-21 | 1986-02-20 | 1986-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-08-21 | 1990-02-20 | 1990-08-22 | $7700.00 | Window Closed / Lapsed |