Automatic ultrafiltration control system
First Claim
1. A method of automatically achieving a target amount of ultrafiltration in a fluid flow transfer device having a first fluid flowing past one surface of a semipermeable membrane and a second fluid flowing past the other surface by the end of a specific overall time period, said method comprisingsupplying said first fluid to said fluid flow transfer device,removing said first fluid from said fluid flow transfer device,generating electrical ultrafiltration rate signals indicative of the difference of the flowrate of the first fluid entering said device and the flowrate of the first fluid leaving said device,generating electrical first fluid pressure signals indicative of the pressure of said first fluid in said device with a first fluid pressure sensor,generating electrical second fluid pressure signals indicative of the pressure of the other liquid flowing through said device with a second fluid pressure sensor,adjusting one of said pressures of said fluids in response to electrical pressure adjustment signals,generating electrical target signals indicative of said target amount of ultrafiltration and said specific time period at control panel means and supplying them to ultrafiltration control means, andautomatically periodically receiving said first and second fluid pressure signals and said ultrafiltration rate signals, computing a coefficient for describing the relationship between the ultrafiltration rate and the difference of pressures of the first and second fluids (the transmembrane pressure), and producing said pressure adjustment signals at said ultrafiltration control means,said adjustment signals indicating transmembrane pressure corresponding to the desired ultrafiltration rate based upon the most recently calculated value of said coefficient, whereby the actual ultrafiltration rate results in achieving the target fluid loss by the end of said overall time period even if the relationship between the fluid pressures and ultrafiltration rate changes during said specific overall period.
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Accused Products
Abstract
A system for supplying fluid for a fluid flow transfer device and achieving target ultrafiltration fluid losses by automatically, periodically monitoring the ultrafiltration rate and transmembrane pressure, computing the transmembrane pressure necessary to achieve the target fluid loss by the end of a session, and adjusting the transmembrane pressure to the computed value.
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Citations
9 Claims
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1. A method of automatically achieving a target amount of ultrafiltration in a fluid flow transfer device having a first fluid flowing past one surface of a semipermeable membrane and a second fluid flowing past the other surface by the end of a specific overall time period, said method comprising
supplying said first fluid to said fluid flow transfer device, removing said first fluid from said fluid flow transfer device, generating electrical ultrafiltration rate signals indicative of the difference of the flowrate of the first fluid entering said device and the flowrate of the first fluid leaving said device, generating electrical first fluid pressure signals indicative of the pressure of said first fluid in said device with a first fluid pressure sensor, generating electrical second fluid pressure signals indicative of the pressure of the other liquid flowing through said device with a second fluid pressure sensor, adjusting one of said pressures of said fluids in response to electrical pressure adjustment signals, generating electrical target signals indicative of said target amount of ultrafiltration and said specific time period at control panel means and supplying them to ultrafiltration control means, and automatically periodically receiving said first and second fluid pressure signals and said ultrafiltration rate signals, computing a coefficient for describing the relationship between the ultrafiltration rate and the difference of pressures of the first and second fluids (the transmembrane pressure), and producing said pressure adjustment signals at said ultrafiltration control means, said adjustment signals indicating transmembrane pressure corresponding to the desired ultrafiltration rate based upon the most recently calculated value of said coefficient, whereby the actual ultrafiltration rate results in achieving the target fluid loss by the end of said overall time period even if the relationship between the fluid pressures and ultrafiltration rate changes during said specific overall period.
Specification