Hydraulic oil well pumping apparatus
View Patent ↗A hydraulic oil well pumping arrangement employs a compensating type hydraulic pump, a directional valving arrangement and a proportioning valving arrangement. When the directional valve is energized, oil is directed to the rod end of the hydraulic cylinder. In one embodiment, a time delay halts the movement of the sucker rod or pumping string to allow accumulation of oil in a slow following well. In another embodiment, the pumping string rapidly falls to the bottom of the stroke in order to shake or jar debris from the string.
1. A method of controlling a hydraulic oil well pumping apparatus mounted to a wellhead above an oil well, wherein the hydraulic oil well pumping apparatus comprises at least two modes of operation, the method comprising the steps of:
a) providing a hydraulic cylinder having a hydraulic cylinder rod that is movable between an upper rod position and a lower rod position, wherein the hydraulic cylinder rod is connected to a sucker rod that extends into the oil well;
b) providing a control system that controls movement of the hydraulic cylinder rod as it moves between the upper and lower rod positions, wherein the control system includes a proportional valve that controls the rate of flow of hydraulic fluid to and from the hydraulic cylinder and wherein the control system further includes a directional valve that diverts hydraulic fluid to and from the hydraulic cylinder;
c) operating the hydraulic oil well pumping apparatus according to a normal pumping mode of operation comprising the steps of:
c1) directing hydraulic fluid into the hydraulic cylinder to lift the hydraulic cylinder rod to the upper rod position;
c2) opening the proportional valve to allow the hydraulic cylinder rod to fall;
c3) slowly closing the proportional valve as the hydraulic cylinder rod approaches the lower rod position to gradually stop the downward motion of the hydraulic cylinder rod; and
c4) repeating steps c1-c4 until a cleaning cycle is requested; and
d) operating the hydraulic oil well pumping apparatus according to a cleaning cycle mode of operation comprising the steps of:
d1) directing hydraulic fluid into the hydraulic cylinder to lift the hydraulic cylinder rod to the upper rod position;
d2) opening the proportional valve to allow the hydraulic cylinder rod to fall;
d3) rapidly closing the proportional valve as the hydraulic cylinder rod approaches the lower rod position to rapidly stop the downward motion of the hydraulic cylinder rod; and
d4) returning the hydraulic oil well pumping apparatus to the normal pumping mode of operation comprising of steps c1-c4.
2. The method of claim 1 , wherein step d4 occurs immediately after step d3.
3. The method of claim 1 , wherein step d2 comprises ramping open the proportional valve to 75%.