Automatic liquid level controller

Claim 2

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and means responsive to said clock pulse source for repetitively actuating said source of acoustic pulses so that said digital controller controls said pump at pre-determined times over a period of time.

Claim 3

The apparatus recited in claim 1 wherein said means for repetitively actuating said source of acoustic pulses includes: a firing time rate circuit, said clock pulses being connected to said firing time rate circuit, said firing time rate circuit having means for adjusting the repetitive firing time of said source of acoustic pulses.

Claim 4

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses continuously coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital mounting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well, said gating means including: a first circuit having an adjustable trigger level, said transducer being connected to said first circuit to produce a start pulse upon the occurrence of the initiating acoustic pulse in said well, said start pulse being applied to start the counting of said clock pulses; and a second circuit having an adjustable trigger level, said transducer being connected to said second circuit to produce a stop pulse upon indication of an acoustic pulse reflected from the liquid surface in said well, said stop pulse being connected to stop said counting; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; and a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 5

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses continuously coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital mounting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well, said gating means including: a first circuit having an adjustable trigger level, said transducer being connected to said first circuit to produce a start pulse upon the occurrence of the initiating acoustic pulse in said well, said start pulse being applied to start the counting of said clock pulses; and a second circuit having an adjustable trigger level, said transducer being connected to said second circuit to produce a stop pulse upon indication of an acoustic pulse reflected from the liquid surface in said well, said stop pulse being connected to stop said counting; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; and a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 6

The apparatus recited in claim 3 further comprising: a calibrated mute time circuit actuated coincidentally with the initiating acoustic pulses and connected to said second circuit to render it inoperative for a known adjustable period of time during and after the occurrence of each initiating acoustic pulse.

Claim 7

The apparatus recited in claim 3 further including a digital mute depth circuit comprising: a manually settable digital register calibrated in units of depth; a comparator, said digital mute depth register and said counting means being connected to said comparator; and a mute depth circuit actuated coincidentally with the initiating acoustic pulses and connected to said second circuit to render it inoperative, said comparator being connected to render said second circuit operative when the count in said digital depth counting means equals the count in said digital mute depth register.

Claim 10

The method recited in claim 6 wherein the generation of initiating acoustic pulses is by the steps of: opening a solenoid-operated valve which communicates with said annulus to release gas under pressure; and changing the time that said solenoid valve remains open to change the acoustic properties of said initiating pulses.

Claim 11

The method recited in claim 6 further comprising: storing a digital representation of said measured time difference; and thereafter printing out a record of liquid level depth at each of said preset times.

Claim 12

The method recited in claim 6 wherein the step of recording includes: recording said digital count as a measure of the depth of the liquid level in said well while said depth is changing to produce a record of the rate of change in depth in said well.

Claim 13

The method recited in claim 6 further comprising: turning said pump on when the counted clock pulses exceed a digital high set point level; turning said pump off when the counted clock pulses fall below a digital low set point level; digitally changing said high and low set point levels so that said record of the change in depth in said well is linear.

Claim 14

The method recited in claim 10 further comprising: confirming a measure of depth which turns said pump on or off by generating initiating acoustic pulses and counting clock pulses in at least two intervals in which clock pulses exceed said digital high set point level or fall below said digital low set point level.

Claim 15

The method recited in claim 11 further comprising: counting the number of intervals in which clock pulses exceed said digital high set point level, and actuating an alarm when the counted number is more than a predetermined amount.

Claim 16

The method recited in claim 6 wherein the step of measuring comprises: digitally counting clock pulses in the intervals between the generation of each initiating acoustic pulse and the detection of the reflected acoustic pulse; repetitively producing a digital count as a measure of the depth of the liquid level in said well, and controlling the operation of said pump from said digital count to maintain the depth of liquid level in said well between desired levels.

Claim 17

The method recited in claim 13 wherein said well has a casing with said pump suspended from a tubing string disposed within said casing, further including calibrating for variations in the acoustic velocity characteristics of the well by the steps of: pumping the liquid in said well down to the known level of the pump inlet in said well and while maintaining the liquid level approximately at the pump inlet repetitively generating initiating pulses; and between initiating pulses changing the number of clock pulses counted until the digital count corresponds with the known level of said pump inlet in said well.

Claim 18

The method recited in claim 13 further comprising: recording the digital count which measures the depth of the liquid level and recording the time of each initiating acoustic pulse.

Claim 19

The method recited in claim 13 further comprising controlling the volume per unit time of liquid pumped from said well by the steps of: turning said pump on when the counted clock pulses exceed a digital high set point level; turning said pump off when the counted clock pulses fall below a digital low set point level; digitally changing said high level; and digitally changing the intervals between the generation of initiating acoustic pulses to pump the desired volume per unit time of liquid.

Claim 22

The method recited in claim 17 further comprising: recording the times at which said pump is turned on and off.

Claim 23

Apparatus for controlling a pump suspended in a well: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and means for producing signals turning said pump on or off in at least two intervals whereby a measure of depth is confirmed before said pump is turned on or off.

Claim 24

Apparatus for controlling a pump suspended in a well: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and means for producing signals turning said pump on or off in at least two intervals whereby a measure of depth is confirmed before said pump is turned on or off.

Claim 25

The apparatus recited in claim 19 wherein said means for producing said signals in at least two intervals includes: means for counting said clock pulses in at least two intervals in which clock pulses exceed said digital high set point signal or fall below said digital low set point signal.

Claim 26

The apparatus recited in claim 35 further comprising: a counter for counting the number of intervals in which clock pulses exceed said digital high set point signal; and means for actuating an alarm when the counted number is more than predetermined amount.

Claim 27

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; said gating means including: a first circuit having an adjustable trigger level, said transducer being connected to said first circuit to produce a start pulse upon the occurrence of the initiating acoustic pulse in said well, said start pulse being applied to start the counting of said clock pulses; and a second circuit having an adjustable trigger level, said transducer being connected to said second circuit to produce a stop pulse upon indication of an acoustic pulse reflected from the liquid surface in said well, said stop pulse being connected to stop said counting; and a calibrated mute time circuit actuated coincidentally with the initiating acoustic pulses and connected to said second circuit to render it inoperative for a known adjustable period of time during and after the occurrence of each initiating acoustic pulse.

Claim 28

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; said gating means including: a first circuit having an adjustable trigger level, said transducer being connected to said first circuit to produce a start pulse upon the occurrence of the initiating acoustic pulse in said well, said start pulse being applied to start the counting of said clock pulses; and a second circuit having an adjustable trigger level, said transducer being connected to said second circuit to produce a stop pulse upon indication of an acoustic pulse reflected from the liquid surface in said well, said stop pulse being connected to stop said counting; and a calibrated mute time circuit actuated coincidentally with the initiating acoustic pulses and connected to said second circuit to render it inoperative for a known adjustable period of time during and after the occurrence of each initiating acoustic pulse.

Claim 29

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well, said gating means including: a first circuit having an adjustable trigger level, said transducer being connected to said first circuit to produce a start pulse upon the occurrence of the initiating acoustic pulse in said well, said start pulse being applied to start the counting of said clock pulses; and a second circuit having an adjustable trigger level, said transducer being connected to said second circuit to produce a stop pulse upon indication of an acoustic pulse reflected from the liquid surface in said well, said stop pulse being connected to stop said counting; a digital controller responsive to said digital counting means for controlling said pump; a manually settable digital register calibrated in units of depth; a comparator, said digital mute depth register and said counting means being connected to said comparator; and a mute depth circuit actuated coincidentally with the initiating acoustic pulses and connected to said second circuit to render it inoperative, said comparator being connected to render said second circuit operative when the count in said digital depth counting means equals the count in said digital mute depth register.

Claim 30

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well, said gating means including: a first circuit having an adjustable trigger level, said transducer being connected to said first circuit to produce a start pulse upon the occurrence of the initiating acoustic pulse in said well, said start pulse being applied to start the counting of said clock pulses; and a second circuit having an adjustable trigger level, said transducer being connected to said second circuit to produce a stop pulse upon indication of an acoustic pulse reflected from the liquid surface in said well, said stop pulse being connected to stop said counting; a digital controller responsive to said digital counting means for controlling said pump; a manually settable digital register calibrated in units of depth; a comparator, said digital mute depth register and said counting means being connected to said comparator; and a mute depth circuit actuated coincidentally with the initiating acoustic pulses and connected to said second circuit to render it inoperative, said comparator being connected to render said second circuit operative when the count in said digital depth counting means equals the count in said digital mute depth register.

Claim 31

Apparatus for controlling a pump suspended from a tubing string disposed within a well casing comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump; and a selectable band pass filter connected between said transducer and said gating means, said filter being settable for a first band pass which passes transducer outputs representing acoustic pulses reflected from the liquid surface of said well and a second pass which passes transducer outputs representing acoustic pulses reflected from collars in said tubing string.

Claim 32

Apparatus for controlling a pump suspended from a tubing string disposed within a well casing comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump; and a selectable band pass filter connected between said transducer and said gating means, said filter being settable for a first band pass which passes transducer outputs representing acoustic pulses reflected from the liquid surface of said well and a second pass which passes transducer outputs representing acoustic pulses reflected from collars in said tubing string.

Claim 33

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means including: a manually adjustable pulse counter producing one pulse output for an adjustable number of input pulses, said clock pulses being applied as input pulses, said adjustable pulse counter having means for manually changing the number of input pulses producing an output pulse in order to calibrate said depth counter for variations in acoustic velocity; and a depth counter for accumulating a pulse for each increment of depth in said well; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; and a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; and a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 34

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means including: a manually adjustable pulse counter producing one pulse output for an adjustable number of input pulses, said clock pulses being applied as input pulses, said adjustable pulse counter having means for manually changing the number of input pulses producing an output pulse in order to calibrate said depth counter for variations in acoustic velocity; and a depth counter for accumulating a pulse for each increment of depth in said well; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; and a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; and a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 35

Apparatus for controlling a pump suspended in a well having a string of tubing disposed within a casing comprising: a source of acoustic pulses coupled to the annulus between said tubing string and said casing; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; and a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; and a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 36

Apparatus for controlling a pump suspended in a well having a string of tubing disposed within a casing comprising: a source of acoustic pulses coupled to the annulus between said tubing string and said casing; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; and a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; and a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 37

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses continuously coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparators, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; a manually settable digital mute depth register; and multiplexing means sequentially connecting said digital registers to said comparator.

Claim 38

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses continuously coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparators, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; a manually settable digital mute depth register; and multiplexing means sequentially connecting said digital registers to said comparator.

Claim 39

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said controller controlling the on/off time of said pump, a digital indication of liquid depth from said counting means being applied to said controller, said controller operating to maintain the location of the liquid surface of said well at a desired depth, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 40

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said controller controlling the on/off time of said pump, a digital indication of liquid depth from said counting means being applied to said controller, said controller operating to maintain the location of the liquid surface of said well at a desired depth, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level.

Claim 41

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and a digital printing recorder responsive to said digital counting means for selectively printing the stored digital depths.

Claim 42

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and a digital printing recorder responsive to said digital counting means for selectively printing the stored digital depths.

Claim 43

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and a digital memory for periodically storing digital counts representing the depth of said liquid surface.

Claim 44

Apparatus for controlling a pump suspended in a well comprising: a source of acoustic pulses coupled to said well; a transducer coupled to said well producing an electric signal in response to the occurrence of acoustic pulses in said well; a clock pulse source; digital counting means; gating means responsive to the output of said transducer for starting the counting of clock pulses by said digital counting means upon the occurrence of an acoustic pulse in said well and for stopping said counting upon detection of the acoustic pulse reflected from the liquid surface in said well; a digital controller responsive to said digital counting means for controlling said pump, said digital controller including: a high level set-point circuit including a manually settable digital register calibrated in units of depth; a low level set-point circuit including a manually settable digital register calibrated in units of depth; a comparator, said digital registers and said counting means being connected to said comparator, said comparator being connected to turn said pump on when the liquid in said well exceeds the high set-point level and to turn said pump off when the liquid in said well falls below the low set-point level; and a digital memory for periodically storing digital counts representing the depth of said liquid surface.