Method for liquid chromatography

Claim 1

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column for a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; estimating the equilibrium value of pressure from said measurements of said characteristic mode at said low value characteristic; increasing the pumping rate of flow until said estimated equilibrium value of pressure is reached; and the step of estimating including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction; and reducing said rate of flow from the pumping system to said predetermined rate of flow.

Claim 2

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column for a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; estimating the equilibrium value of pressure from said measurements of said characteristic mode at said low value characteristic; increasing the pumping rate of flow until said estimated equilibrium value of pressure is reached; and the step of estimating including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction; and reducing said rate of flow from the pumping system to said predetermined rate of flow.

Claim 6

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of measuring, at a time of low value of pressure, a characteristic of fluid including the step of measuring the pressure of fluid being transferred from the pumping system to the chromatographic column at a low value of pressure; the step of increasing the rate of flow including the steps of estimating the equilibrium value of pressure from said characteristic; and increasing the pumping rate of flow until said estimated equilibrium value of pressure is reached; the step of measuring a characteristic including the step of measuring the derivative with respect to time of the pressure of fluid being transferred from the pumping system to the chromatographic column at a low value of pressure; the step of increasing the rate of flow including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction; and the step of reducing said rate of flow of pumping to said predetermined rate of flow including the steps of storing a value representing the instantaneous pressure when the pressure time derivative reaches said predetermined point; comparing the stored value of instantaneous pressure with the instantaneous pressure as it changes; and slowing the rate of flow when the ratio of the maximum pressure time derivative minus the instantaneous time derivative to the maximum pressure-time derivative multiplied by the instantaneous pressure value is larger than the stored pressure value.

Claim 7

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of measuring, at a time of low value of pressure, a characteristic of fluid including the step of measuring the pressure of fluid being transferred from the pumping system to the chromatographic column at a low value of pressure; the step of increasing the rate of flow including the steps of estimating the equilibrium value of pressure from said characteristic; and increasing the pumping rate of flow until said estimated equilibrium value of pressure is reached; the step of measuring a characteristic including the step of measuring the derivative with respect to time of the pressure of fluid being transferred from the pumping system to the chromatographic column at a low value of pressure; the step of increasing the rate of flow including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction; and the step of reducing said rate of flow of pumping to said predetermined rate of flow including the steps of storing a value representing the instantaneous pressure when the pressure time derivative reaches said predetermined point; comparing the stored value of instantaneous pressure with the instantaneous pressure as it changes; and slowing the rate of flow when the ratio of the maximum pressure time derivative minus the instantaneous time derivative to the maximum pressure-time derivative multiplied by the instantaneous pressure value is larger than the stored pressure value.

Claim 10

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic of fluid including the steps of counting drops from the column and deriving a signal in analog form representing the drops; and applying a correction factor to that signal so as to cause it to represent the outflow from the column.

Claim 11

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic of fluid including the steps of counting drops from the column and deriving a signal in analog form representing the drops; and applying a correction factor to that signal so as to cause it to represent the outflow from the column.

Claim 15

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of measuring a characteristic of fluid including the steps of counting drops from the column and deriving a signal in analog form representing the drops; and applying a correction factor to that signal so as to cause it to represent the outflow from the column; the step of applying a correction factor including the step of converting the signal to digital form and applying a digital correction factor; the step of increasing the rate of pumping flow including the step of increasing the rate of flow until the outflow from the chromatograph means equals the predetermined rate of flow; the step of increasing the rate of flow including the steps of comparing the measured outflow with a preset outflow and generating a resulting signal; and causing said resulting signal to control the rate of pumping until said measured outflow equals said preset outflow; and the step of increasing the rate of flow including the steps of applying a reference signal to the pumping system corresponding to the equilibrium rate while the chromatographic means is under no load; generating a calibration factor signal by comparing the reference signal with the signal derived from the outflow measuring circuit when the chromatographic column has the desired outflow rate; multiplying the calibration factor signal by the measured signal and comparing it to the desired signal during operation of the chromatographic column under load; and discontinuing application of the reference signal to the motor control circuit and applying the factored measured signal when the calibrated measured signal differs from the desired signal.

Claim 16

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of measuring a characteristic of fluid including the steps of counting drops from the column and deriving a signal in analog form representing the drops; and applying a correction factor to that signal so as to cause it to represent the outflow from the column; the step of applying a correction factor including the step of converting the signal to digital form and applying a digital correction factor; the step of increasing the rate of pumping flow including the step of increasing the rate of flow until the outflow from the chromatograph means equals the predetermined rate of flow; the step of increasing the rate of flow including the steps of comparing the measured outflow with a preset outflow and generating a resulting signal; and causing said resulting signal to control the rate of pumping until said measured outflow equals said preset outflow; and the step of increasing the rate of flow including the steps of applying a reference signal to the pumping system corresponding to the equilibrium rate while the chromatographic means is under no load; generating a calibration factor signal by comparing the reference signal with the signal derived from the outflow measuring circuit when the chromatographic column has the desired outflow rate; multiplying the calibration factor signal by the measured signal and comparing it to the desired signal during operation of the chromatographic column under load; and discontinuing application of the reference signal to the motor control circuit and applying the factored measured signal when the calibrated measured signal differs from the desired signal.

Claim 19

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic of a fluid including the steps of measuring the pressure caused by a pump supplying fluid to the chromatographic system; measuring a dynamic characteristic of the system which is inversely proportional to the pressure; establishing a ratio between a point on the dynamic characteristic and its range from maximum to zero; measuring the pressure at said point; and calculating other points of pressure from proportionality between said dynamic characteristic and said pressure measurement.

Claim 20

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic of a fluid including the steps of measuring the pressure caused by a pump supplying fluid to the chromatographic system; measuring a dynamic characteristic of the system which is inversely proportional to the pressure; establishing a ratio between a point on the dynamic characteristic and its range from maximum to zero; measuring the pressure at said point; and calculating other points of pressure from proportionality between said dynamic characteristic and said pressure measurement.

Claim 24

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of low value of pressure, a characteristic fo fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of flow comprises the steps of estimating the equilibrium pressure for a constant flow-rate chromatographic run from said measurement of a characteristic; increasing the pump motor speed rapidly until said pressure is reached; permitting the flow rate to stabilize at said set pressure; repeating the process of estimating the pressure and increasing the speed of the pumping system to the estimated pressure until the flow rate is close to the constant flow rate; and operating said chromatograph at the constant flow rate.

Claim 25

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of low value of pressure, a characteristic fo fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of flow comprises the steps of estimating the equilibrium pressure for a constant flow-rate chromatographic run from said measurement of a characteristic; increasing the pump motor speed rapidly until said pressure is reached; permitting the flow rate to stabilize at said set pressure; repeating the process of estimating the pressure and increasing the speed of the pumping system to the estimated pressure until the flow rate is close to the constant flow rate; and operating said chromatograph at the constant flow rate.

Claim 28

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of increasing the rate of flow comprising the steps of estimating the equilibrium pressure for a constant-flow-rate chromatographic run from said measurement of a characteristic; increasing the pump motor speed rapidly until said pressure is reached; permitting the flow rate to stabilize at said set pressure; repeating the process of estimating the pressure and increasing the speed of the pumping system to the estimated pressure until the flow rate is close to the constant flow rate; and operating said chromatograph at the constant flow rate; the step of increasing the speed of the pumping system including the steps of comparing the pressure with the estimated pressure to derive a difference signal; and applying the difference signal to a feedback loop to control the pumping system speed until the set pressure equals the estimated pressure; the step of operating the chromatograph at a constant flow rate including the step of applying a potential to the motor which is constant, whereby the motor drives the pump at a constant flow rate; and the step of determining when the pressure is equal to the estimated pressure comprises the steps of determining when the slope of the pressure-time curve is approximately zero; determining when the difference between the set pressure and the measured pressure is approximately zero; and selecting the time when both the slope of the pressure-time curve is approximately zero and the difference between the measured pressure and set pressure is approximately zero as the end of the transitory period.

Claim 29

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of increasing the rate of flow comprising the steps of estimating the equilibrium pressure for a constant-flow-rate chromatographic run from said measurement of a characteristic; increasing the pump motor speed rapidly until said pressure is reached; permitting the flow rate to stabilize at said set pressure; repeating the process of estimating the pressure and increasing the speed of the pumping system to the estimated pressure until the flow rate is close to the constant flow rate; and operating said chromatograph at the constant flow rate; the step of increasing the speed of the pumping system including the steps of comparing the pressure with the estimated pressure to derive a difference signal; and applying the difference signal to a feedback loop to control the pumping system speed until the set pressure equals the estimated pressure; the step of operating the chromatograph at a constant flow rate including the step of applying a potential to the motor which is constant, whereby the motor drives the pump at a constant flow rate; and the step of determining when the pressure is equal to the estimated pressure comprises the steps of determining when the slope of the pressure-time curve is approximately zero; determining when the difference between the set pressure and the measured pressure is approximately zero; and selecting the time when both the slope of the pressure-time curve is approximately zero and the difference between the measured pressure and set pressure is approximately zero as the end of the transitory period.

Claim 31

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic of the fluid comprising the steps of deriving a signal representing the pressure of the pump; taking the derivative of the signal representing the derivative of the pump; establishing a set equilibrium pressure; comparing the measured pressure with the equilibrium pressure; and detecting when the slope of the pressure-time characteristic and the difference between measured and set pressure characteristic are both substantially zero, whereby the equilibrium time is detected.

Claim 32

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic of the fluid comprising the steps of deriving a signal representing the pressure of the pump; taking the derivative of the signal representing the derivative of the pump; establishing a set equilibrium pressure; comparing the measured pressure with the equilibrium pressure; and detecting when the slope of the pressure-time characteristic and the difference between measured and set pressure characteristic are both substantially zero, whereby the equilibrium time is detected.

Claim 33

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; deriving a signal representing the rate of flow of said fluid as it leaves the outlet of the chromatographic column; detecting characteristics of an effluent in the chromatograph; recording the characteristics of the effluent on a chart; and varying the speed of the chart in direct proportion to the signal representing the rate of flow of fluid as it leaves the outlet.

Claim 34

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; deriving a signal representing the rate of flow of said fluid as it leaves the outlet of the chromatographic column; detecting characteristics of an effluent in the chromatograph; recording the characteristics of the effluent on a chart; and varying the speed of the chart in direct proportion to the signal representing the rate of flow of fluid as it leaves the outlet.

Claim 35

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; estimating the equilibrium value of pressure from said characteristic; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic includes the step of measuring the derivative with respect to time of the pressure of fluid caused by the pumping system at a low value of pressure.

Claim 36

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; estimating the equilibrium value of pressure from said characteristic; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of measuring a characteristic includes the step of measuring the derivative with respect to time of the pressure of fluid caused by the pumping system at a low value of pressure.

Claim 38

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of increasing the rate of flow including the steps of estimating the equilibrium value of pressure from said characteristic; and increasing the pumping rate of flow until said estimated equilibrium value of pressure is reached; the step of measuring a characteristic including the step of measuring the derivative with respect to time of the pressure of fluid being transferred from the pumping system to the chromatographic column at a low value of pressure; the step of increasing the rate of flow including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction, and the step of reducing said rate of flow of pumping to said predetermined rate of flow including the steps of storing a value representing the instantaneous pressure when the pressure time derivative reaches said predetermined fraction; comparing the stored value of instantaneous pressure with the instantaneous pressure as it changes; and slowing the rate of flow when the ratio of the maximum pressure time derivative minus the time derivative at the predetermined fraction to the maximum pressure time derivative multiplied by the instantaneous pressure measured as it changes becomes substantially equal to the stored pressure value.

Claim 39

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of increasing the rate of flow including the steps of estimating the equilibrium value of pressure from said characteristic; and increasing the pumping rate of flow until said estimated equilibrium value of pressure is reached; the step of measuring a characteristic including the step of measuring the derivative with respect to time of the pressure of fluid being transferred from the pumping system to the chromatographic column at a low value of pressure; the step of increasing the rate of flow including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction, and the step of reducing said rate of flow of pumping to said predetermined rate of flow including the steps of storing a value representing the instantaneous pressure when the pressure time derivative reaches said predetermined fraction; comparing the stored value of instantaneous pressure with the instantaneous pressure as it changes; and slowing the rate of flow when the ratio of the maximum pressure time derivative minus the time derivative at the predetermined fraction to the maximum pressure time derivative multiplied by the instantaneous pressure measured as it changes becomes substantially equal to the stored pressure value.

Claim 42

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of increasing the rate of flow including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction.

Claim 43

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of increasing the rate of flow including the steps of taking the time derivative of the pressure; measuring the pressure at a predetermined fraction of the difference between the maximum time derivative of the pressure and zero; and multiplying the pressure at that point by a factor which is the reciprocal of the predetermined fraction.

Claim 44

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow: measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of pumping flow including the step of increasing the rate of flow until the outflow from the chromatograph means equals the predetermined rate of flow.

Claim 45

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow: measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of pumping flow including the step of increasing the rate of flow until the outflow from the chromatograph means equals the predetermined rate of flow.

Claim 46

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of flow including the steps of comparing the measured outflow with a preset outflow and generating a resulting signal; and causing said resulting signal to control the rate of pumping until said measured outflow equals said preset outflow.

Claim 47

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of flow including the steps of comparing the measured outflow with a preset outflow and generating a resulting signal; and causing said resulting signal to control the rate of pumping until said measured outflow equals said preset outflow.

Claim 48

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of flow including the steps of applying a reference signal to the pumping system corresponding to the equilibrium rate while the chromatographic means is under no load; generating a calibration factor signal by comparing the reference signal with the signal derived from the outflow measuring circuit when the chromatographic column has the desired outflow rate; multiplying the calibration factor signal by the measured signal and comparing it to the desired signal during operation of the chromatographic column under load; and discontinuing application of the reference signal to the motor control circuit and applying the factored measured signal when the calibrated measured signal differs from the desired signal.

Claim 49

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; and the step of increasing the rate of flow including the steps of applying a reference signal to the pumping system corresponding to the equilibrium rate while the chromatographic means is under no load; generating a calibration factor signal by comparing the reference signal with the signal derived from the outflow measuring circuit when the chromatographic column has the desired outflow rate; multiplying the calibration factor signal by the measured signal and comparing it to the desired signal during operation of the chromatographic column under load; and discontinuing application of the reference signal to the motor control circuit and applying the factored measured signal when the calibrated measured signal differs from the desired signal.

Claim 52

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of measuring a characteristic of fluid including the step of measuring the fluid outflow of the chromatograph; the step of increasing the rate of flow including the steps of applying a reference signal to the pumping system corresponding to the equilibrium rate while the chromatographic means is under no load; generating a calibration factor signal by comparing the reference signal with the signal derived from the outflow measuring circuit when the chromatographic column has the desired outflow rate; multiplying the calibration factor signal by the measured signal and comparing it to the desired signal during operation of the chromatographic column under load; and discontinuing application of the reference signal to the motor control circuit and applying the factored measured signal when the calibrated measured signal differs from the desired signal.

Claim 53

A method of rapidly bringing a chromatographic column to equilibrium pressure comprising the steps of: setting a pumping speed for pumping fluid from a pumping system into said column at a predetermined rate of flow; measuring, at a time of a low value of pressure, a characteristic of fluid being transferred from the pumping system to the chromatographic column related to the pressure of the fluid; increasing the rate of flow from the pumping system under the control of at least said measured characteristic until the equilibrium value of pressure is reached; reducing said rate of flow from the pumping system to said predetermined rate of flow; the step of measuring a characteristic of fluid including the step of measuring the fluid outflow of the chromatograph; the step of increasing the rate of flow including the steps of applying a reference signal to the pumping system corresponding to the equilibrium rate while the chromatographic means is under no load; generating a calibration factor signal by comparing the reference signal with the signal derived from the outflow measuring circuit when the chromatographic column has the desired outflow rate; multiplying the calibration factor signal by the measured signal and comparing it to the desired signal during operation of the chromatographic column under load; and discontinuing application of the reference signal to the motor control circuit and applying the factored measured signal when the calibrated measured signal differs from the desired signal.

Claim 56

A method of operating a chromatograph comprising the steps of: applying fluid from a pumping system into a chromatographic column system; detecting chromatographic peaks in the effluent as the fluid passes through the chromatographic column system; recording said chromatographic peaks; measuring the rate of flow of said fluid from said chromatographic column system and generating a signal related thereto; and controlling the rate of recording said peaks in response to said signal so that the rate of recording is directly proportional to the rate of flow of fluid between the pumping system and the chromatographic column system.

Claim 57

A method of operating a chromatograph comprising the steps of: applying fluid from a pumping system into a chromatographic column system; detecting chromatographic peaks in the effluent as the fluid passes through the chromatographic column system; recording said chromatographic peaks; measuring the rate of flow of said fluid from said chromatographic column system and generating a signal related thereto; and controlling the rate of recording said peaks in response to said signal so that the rate of recording is directly proportional to the rate of flow of fluid between the pumping system and the chromatographic column system.