Valve control system and method

Claim 2

In a method for applying a control signal to a valve controlling the flow of fluid in a pipeline for operating the valve in response to a pressure drop of predetermined character within the pipeline, the steps of generating an electrical pressure signal having a magnitude corresponding to the instantaneous pressure within the pipeline, generating an electrical reference signal having a magnitude corresponding to the average pressure within the pipeline, comparing the magnitudes of the pressure and reference signals, generating a ramp signal having a magnitude increasing at a predetermined rate when the magnitude of the pressure signal is less than the magnitude of the reference signal, combining the pressure and ramp signals to produce a composite signal, comparing the magnitudes of the composite and reference signals, and delivering a control signal for operating the pipeline valve when the magnitude of the composite signal is less than the magnitude of the reference signal for a predetermined time.

Claim 3

A method as in claim 1 together with the additional steps of generating a second control signal for resetting the valve a predetermined time after the first named control signal is delivered and thereafter repeating the steps defined by Claim 1 to produce an additional control signal for again operating the valve when the magnitude of the composite signal is again less than the magnitude of the references signal for the predetermined time.

Claim 4

A method as in claim 2 wherein the steps of generating the second control signal and repeating the steps defined by Claim 1 are successively repeated a predetermined number of times.

Claim 5

In a system for applying a control signal to a valve in a pipeline for operating the valve in response to a pressured drop of predetermined character within the pipeline, pressure signal generating means for generating an electrical pressure signal having a magnitude corresponding to the instantaneous pressure within the pipeline, means responsive to said pressure signal for generating a reference signal having a magnitude corresponding to the average pressure within the pipeline, ramp generating means for generating a ramp signal having a magnitude increasing at a predetermined rate from an initial level, summation means for combining the pressure and ramp signals to form a composite signal, comparator means for comparing the magnitude of the composite signal with the magnitude of the reference signal, means connected to the comparator means and ramp generating means for resetting the ramp signal to its initial level when the magnitude of the composite signal is at least as great as the magnitude of the reference signal, and means responsive to the ramp signal for producing an output control signal when the magnitude of said ramp signal reaches a predetermined level.

Claim 6

In a system for applying a control signal to a valve in a pipeline for operating the valve in response to a pressured drop of predetermined character within the pipeline, pressure signal generating means for generating an electrical pressure signal having a magnitude corresponding to the instantaneous pressure within the pipeline, means responsive to said pressure signal for generating a reference signal having a magnitude corresponding to the average pressure within the pipeline, ramp generating means for generating a ramp signal having a magnitude increasing at a predetermined rate from an initial level, summation means for combining the pressure and ramp signals to form a composite signal, comparator means for comparing the magnitude of the composite signal with the magnitude of the reference signal, means connected to the comparator means and ramp generating means for resetting the ramp signal to its initial level when the magnitude of the composite signal is at least as great as the magnitude of the reference signal, and means responsive to the ramp signal for producing an output control signal when the magnitude of said ramp signal reaches a predetermined level.

Claim 7

A system as in claim 4 wherein said pressure signal generating means includes a pressure sensing element having an electrical resistance corresponding to the pressure in the pipeline and current generating means connected to said element to produce a voltage across said element having a magnitude corresponding to said pressure.

Claim 8

A system as in claim 4 wherein said comparator means includes a differential amplifier connected for receiving one input from the summation means and another input from the means for generating the reference signal.

Claim 9

A system as in claim 4 wherein the means responsive to the ramp signal includes a level detector and relay Means controlled by said level detector.

Claim 10

A system as in claim 4 together with means for producing a second control signal for resetting the valve and resetting said ramp signal to its initial level a predetermined time after the output control signal is produced.

Claim 11

In a valve control system for use with a pipeline valve having actuating means for opening and closing said valve, pressure signal generating means for monitoring the pressure in the pipeline and generating an electrical pressure signal having a magnitude corresponding to the pressure in the pipeline, memory means for storing a reference signal having a magnitude corresponding to average pressure in the pipeline, ramp generating means for generating a ramp signal having a magnitude increasing at a predetermined rate from an initial level of zero, summation means connected for receiving the pressure and ramp signals and combining said signals to form a composite signal having a magnitude corresponding to the sum of the magnitudes of the pressure and ramp signals, differential amplifier means connected for receiving inputs from the memory means and summation means and producing an output signal corresponding to the difference in magnitude between the reference and composite signals, first level detector means connected to the differential amplifier means and ramp generating means for initiating the generation of the ramp signal when the output of the differential amplifier means reaches a predetermined level and resetting the ramp signal to its initial level when the output of the differential amplifier means is below said predetermined level, and second level detector means connected to said ramp generating means for producing an output control signal for actuating the valve actuating means to operate the valve when said ramp signal reaches a predetermined level.

Claim 12

In a valve control system for use with a pipeline valve having actuating means for opening and closing said valve, pressure signal generating means for monitoring the pressure in the pipeline and generating an electrical pressure signal having a magnitude corresponding to the pressure in the pipeline, memory means for storing a reference signal having a magnitude corresponding to average pressure in the pipeline, ramp generating means for generating a ramp signal having a magnitude increasing at a predetermined rate from an initial level of zero, summation means connected for receiving the pressure and ramp signals and combining said signals to form a composite signal having a magnitude corresponding to the sum of the magnitudes of the pressure and ramp signals, differential amplifier means connected for receiving inputs from the memory means and summation means and producing an output signal corresponding to the difference in magnitude between the reference and composite signals, first level detector means connected to the differential amplifier means and ramp generating means for initiating the generation of the ramp signal when the output of the differential amplifier means reaches a predetermined level and resetting the ramp signal to its initial level when the output of the differential amplifier means is below said predetermined level, and second level detector means connected to said ramp generating means for producing an output control signal for actuating the valve actuating means to operate the valve when said ramp signal reaches a predetermined level.

Claim 13

A valve control system as in claim 9 wherein said memory means includes a capacitor connected to said differential amplifier means in such manner that said capacitor is charged in response to an increase in the magnitude of said pressure signal and remains charged even though said signal thereafter decreases in magnitude, together with means connected to the capacitor and first level detector means for at least partially discharging said capacitor when the ramp signal is reset to its initial level.

Claim 14

A valve control system as in claim 9 further including relay means connected to said second level detector means for applying the output control signal to the valve actuating means.

Claim 15

A valve control system as in claim 9 together with sequencing means responsive to the output control signal for producing a second control signal for actuating the valve actuating means to reset the valve a predetermined time after said output control signal is produced, said sequencing means also being connected for resetting the ramp signal to its initial level at said predetermined time.

Claim 16

A valve control system as in claim 12 wherein said sequencing means includes means for producing the second control signal and resetting the ramp signal each time the output control signal is produced for a predetermined number of times.

Claim 17

In a control system for producing an output control signal when an analog input signal changes in a predetermined manner, means responsive to the input signal for generating a reference signal having a magnitude corresponding to the average magnitude of the input signal, ramp generating means for generating a ramp signal having a magnitude increasing at a predetermined rate from an initial level, summation means for combining the input and ramp signals to form a composite signal, comparator means for comparing the magnitude of the composite signal with the magnitude of the reference signal, means connected to the comparator means and ramp generating means for maintaining the ramp signal at its initial level when the magnitude of the composite signal is at least as great as the magnitude of the reference signal, and meanS responsive to the ramp signal for producing an output control signal when the magnitude of the ramp signal reaches a predetermined level.

Claim 18

In a control system for producing an output control signal when an analog input signal changes in a predetermined manner, means responsive to the input signal for generating a reference signal having a magnitude corresponding to the average magnitude of the input signal, ramp generating means for generating a ramp signal having a magnitude increasing at a predetermined rate from an initial level, summation means for combining the input and ramp signals to form a composite signal, comparator means for comparing the magnitude of the composite signal with the magnitude of the reference signal, means connected to the comparator means and ramp generating means for maintaining the ramp signal at its initial level when the magnitude of the composite signal is at least as great as the magnitude of the reference signal, and meanS responsive to the ramp signal for producing an output control signal when the magnitude of the ramp signal reaches a predetermined level.

Claim 19

A control system as in claim 14 wherein the comparator means includes a differential amplifier connected for receiving one input from the summation means and another input from the means for generating the reference signal.

Claim 20

A control system as in claim 15 wherein the means responsive to the ramp signal includes a level detector and relay means controlled by said level detector.

Claim 21

A control system as in claim 15 wherein the means for generating the reference signal includes a capacitor connected for charging when the magnitude of the input signal increases.

Claim 22

A control system as in claim 15 together with means responsive to the output control signal for producing a second control signal and resetting the ramp signal to its initial level a predetermined time after said output control signal is produced.

Claim 23

A control system as in claim 18 wherein the last named means includes means for producing the second control signal and resetting the ramp signal a predetermined number of times.

Claim 24

In a method for producing an output control signal when an analog input signal changes at a rate greater than a predetermined rate, the steps of generating a reference signal having a magnitude corresponding to the average magnitude of the input signal, comparing the magnitudes of the input and reference signals, generating a ramp signal which increases from an initial level at the predetermined rate when the magnitude of the input signal is less than the magnitude of the reference signal, combining the input and ramp signals to form a composite signal having a magnitude less than the magnitude of the reference signal when the magnitude of the input signal is decreasing at a rate greater than the predetermined rate, comparing the magnitudes of the composite and reference signals, and producing an output control signal when the magnitude of the composite signal is less than the magnitude of the reference signal.

Claim 25

In a method for producing an output control signal when an analog input signal changes at a rate greater than a predetermined rate, the steps of generating a reference signal having a magnitude corresponding to the average magnitude of the input signal, comparing the magnitudes of the input and reference signals, generating a ramp signal which increases from an initial level at the predetermined rate when the magnitude of the input signal is less than the magnitude of the reference signal, combining the input and ramp signals to form a composite signal having a magnitude less than the magnitude of the reference signal when the magnitude of the input signal is decreasing at a rate greater than the predetermined rate, comparing the magnitudes of the composite and reference signals, and producing an output control signal when the magnitude of the composite signal is less than the magnitude of the reference signal.

Claim 26

A method as in claim 20 wherein the level of the ramp signal is monitored and the output control signal is produced when the ramp signal reaches a predetermined level.

Claim 27

A method as in claim 20 together with the additional steps of generating a second control signal a predetermined time after the output control signal is produced and thereafter repeating the steps defined by claim 20 to produce an additional output control signal if the magnitude of the composite signal is still less than the magnitude of the reference signal.

Claim 28

A method as in claim 22 wherein the steps of generating the second control signal and repeating the steps defined by claim 20 are successively repeated a predetermined number of times.