US2671356A

US2671356A - Pneumatic time compensator

Info

Publication number: US2671356A
Application number: US270660A
Authority: US
Inventors: Edgar W Patterson
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-02-08
Filing date: 1952-02-08
Publication date: 1954-03-09
Anticipated expiration: 1971-03-09

Description

March 9, 1954 E. w. PATTERSON 2,

PNEUMATIC TIME COMPENSATOR Filed Feb. 8, 1952 '5 Sheets-Sheet 2 AvraQA/a March 9, 1954 E. w. PATTERSON 2,671,356

PNEUMATIC TIME COMPENSATOR Filed Feb. 8, 1952 3 Sheets-Sheet 3 v A7770/QA/Ef Patented Mar. 9, l954 UNITED STATES PATENT OFFICE PNEUMATIC TIME COMPENSATOR Edgar W. Patterson, Downey, Calif.

Application February 8, 1952, Serial No. 270,660

23 Claims.

The present invention is an improvement on my co-pending application Serial No. 129,233 for Hydraulic Time Compensator, filed November 25, 1949, now Patent No. 2,651,945.

My invention relates to balancing systems for machines utilizing reciprocal motion, and more particularly to apparatus for measuring and subsequently automatically causing the time interval to become equal for both of the one hundred eighty degree (180) half cycles, or the up and down or forward and backward movements of an oscillating or reciprocating machine such as an air balanced pumping unit for oil or water wells. Such an air balanced pumping unit is disclosed in one of my prior patents, Reissue No. 20,287, March 9, 1937.

Although a balancing system such as the above mentioned one described in my Reissue Patent No. 20,287, March 9, 937, will normally maintain a substantially constant torque on the prime mover of an oil well pumping unit or other reciprocating unit, changes in the load on the reciprocating member cause variations in the torque on the prime mover during different parts of the cycle of the reciprocating unit and, thus cause variations in the time which it takes for the reciprocating unit to move through each half-cycle. These variations in th load cause stresses throughout the unit which lead to a shortening of the life of the unit.

Consequently, it is an object of my invention to produce a time compensator which reacts to deviations in the time intervals for the halfcycles of a reciprocating unit in such a way that the load on one of th half-cycles is substantially equalized to the load on the other half cycle.

Another object of my invention is to produce a time compensator which reacts to deviations in the time intervals of the half-cycles of an air balanced pumping unit in such a way that the balancing pressure is adjusted to that pressure which will substantially equalize the well load and hence equalize the time intervals of the halfcycles of the pumping unit.

Another object of my invention is to produce a time compensator which will automatically maintain a substantially constant torque on the prime mover of an air balanced pumping unit for oil or water wells.

Another object of my invention is to produce a time compensator which will accurately measure the half-cycle time intervals of a reciprocating unit and balance these time intervals in accordance with such measurement.

Another object of my invention is to produce 2 a time compensator which utilizes air to measure the half-cycles of a reciprocating unit and to actuate a balancing device in accordance with such measurement. I

Another object of my invention is to produce a pneumatic tim compensator of the character described which can be adjusted to compensate to any poundage over Or under a perfect balance, within reasonable values, so that the compensator can be used for any type of pumping wherein an off balance may be desired.

A further object of my invention is to produce a pneumatic time compensator of the character described which may utiliz air supplied from the balancing system of an air balanced pumping unit, or other source of supply, to adjust the air pressure within said air balancing unit so that the down and up strokes of such pumping unit are properly balanced.

Other objects and advantages of my invention will be apparent from the following description and claims, the novelty consisting in the features of construction, combination of parts, the unique relations of the members and the relative proportioning, disposition and operation thereof, all as is more completely outlined herein and a is particularly pointed out in the appended claims.

In the accompanying drawings, forming a part of the present specification,

Figure 1 is a sectional view of my invention showing both the pressure control unit and the compensator unit.

Figure 2 is a side elevation, partly in section, along the line 2-2 in Figure 1, showing the details of my pressure control unit.

Figure '3 is a sectional view along the line 3-3 in Figure 1, showing my spring valve action return mechanism.

Figure 4 is a plan view of my invention.

Figure 5 is a sectional view along the line 5-5v in Figure 1.

Referring to the drawings, my pneumatic time compensator comprises two principal elements, a pressure control unit I0 and a compensator unit My pressure control unit In is primarily contained within a housing [4 which in turn is secured to a compensator unit housing l6 by means of bolts l8.

Centrally positioned within pressure control unit housing I4 is an input shaft 20. Integrally attached to input shaft 20 by means of pins 22 and 24 are a pair of annular collars. 26 and 28, respectively. Collars 26 and 28 are journalled in bearings 30 and 32, respectively, to permit input shaft 20 to freely rotate within pressure control unit housing I4. Bearing 30 is mounted within a disc 3| which is clamped in position in housing I4 by set-screw 33.

Integrally attached to the outer end of input shaft 20 is a crank arm 34, the other end of arm 34 being pivotally connected to a flexible link cable 36 by means of crank pin 38 which is pivotally connected to the walking beam of an oil well pumping rig, or to any reciprocal member of a reciprocating unit which is to be balanced (not shown).

I provide a flange at one end of my collar 26 to form a clutch plate 40 which is operatively connected to a second clutch plate 42 by means of a clutch facing 44 whichv may be mounted free on either of the clutch plates 40 or 42. My clutch plate 42 is freely rotatable about input shaft 20, being mounted on bushing 46 and ball bearings 48. j 1'.- provide a constant clutch pressure on clutch facing, 44 by means of compression springs 41 which are compressed between collar 28 and a tubularmember 49 that is slideably mounted on shaft 20. Tubular member 49 transmits the constant force of springs 41 to clutch plate 42 through bearing 48.

I, provide a pair of valve operating lugs 55. and 2 which are integrally mounted on the back of clutchplate 42. As best illustrated in Figure 2, these lugs are preferably so disposed about the centralaxis of input shaft 20 that a straight line will intersect the tops of both lugs and the center of input shaft 20.

Lugs

50 and 52 are normally kept in their extreme clockwise position in Figure 2 by one or more clock springs, such as

clock springs

54 and 56 shown in Figure 1. One end of

springs

54 and 56 is aihxed to shaft 20. and the other end is anchored to a pin-.58 supported by disc 3|. I maintain the correct tension in my springs 54 and; 56 by adjusting disc 3 I, which may be rotated by loosening screw 33.

As an alternative embodiment of my invention I sometimes provide a link rod in place of my. flexible cable 36 to connect my crank arm 34 with the reciprocal unit (not shown) to be balanced. In this construction of'my invention the link rod which replaces flexible cable 36 positively moves the crank arm downward as well asupward, so that my return-

action clock springs

54 and 56 are unnecessary and may be omitted from the structure.

I limit the amount of rotation of my plate 42 by an eccentric stop-slug 60 which is mounted on one endof a shaft 62 that is rotatably mounted in a passage 64 in one side of my housing M. A set screw 65 in my eccentric stop-lug 60. prevents relative motion between stop-lug 60 and shaft 62.

Mounted outside of my housing l4, on the outer end of shaft 62, is a circular head 66 which is locked in position on shaft 52 by means of a set screw 68. I manually turn my circular head 66 until my eccentric stop-lug 60 is properly positioned within the housing I4 and then I lock my circular head 66, and hence my shaft 62 and my stop-lug 60, against rotation by tightening up a set screw 69 in my circular head 65 which is adapted to abut against the outside of housing 14.

The .upper and lower sides of my eccentric lug 60- form faces wand 12, respectively, which are adaptedato respectively engagea pairof stop- 4

pins

14 and 16 that are integrally mounted on the back of my clutch plate 42.

Reciprocal motion of the walking beam or other reciprocating element (not shown) will cause reciprocation of flexible cable 36 and consequently it will cause oscillation of crank 34 and input shaft 20.

Taking the starting point as the position shown in Figure 2, upward movement of flexible cable 36 will. cause upward movement of crank arm 34 and hence it will causecounterclockwise movement of input shaft 2!]. Clutch plate 40, which is integrally attached to shaft 20, will have the same counterclockwise angular movement as the shaft 20.

As this counterclockwise movement of clutch plate 48 is commenced, clutch plate 42 will be moved counterclockwise because of the operative connection between clutch plates and 42 through the clutch facing 44. This counterclockwise movement of clutch plate 42, and the consequent raising of lug 50 and lowering of lug 52, will continue until stop-pin 76 engages face 12 of eccentric stop-lug 60. This engagement of pin 16 and face 12 will completely arrest the counterclockwise movement of clutch-plate 42 and the upward and downward movement of lugs 50 and 5.2, respectively. Any further movement of shaft 26 and clutch plate 40 in a counterclockwise direction will not carry clutch plate 42, but will cause slideable engagement between clutch plates 40 and 42 through clutch facing 44, whereby clutch plate 40 will be free to move counterclockwise to the limit of its oscillation.

When flexible cable 36 begins to move downward in accordance with thecommencement of a new half-cycle of oscillation, shaft 25 and clutch-plate 40 immediately commence to move clockwise under the influence of

springs

54 and 56. Plate 40 then picks up plate 42 in the manner hereinbefore described, and plate 42 will rotate clockwise until its motion is arrested by contact between stop pin 14' and face 16 when the lug 50 is at its lowest point and lug 52 is at its highest point. At that time, there will be sliding friction between the clutch plates 40 and 42, whereby clutch plate 49 will be permitted to rotate under the influence of

springs

54 and 56 until the downward motion of cable 36 ceases.

In like manner, as soon as my flexible cable 36 begins to move upward from its lowest position, clutch plate 40 immediately commences to move counterclockwise. Plate then picks up plate and the two will rotate together until the motion of plate 42 is stopped by contact between stop pin 16 and face 12 of stop-lug 65. Plate 40 will continue to rotate alone until its direction of rotation is reversed.

In this manner, lug will be up and lug 52 will be down for an interval of time substantially equal to the length of time that flexible cable 36*is moving from the bottom to the top of its stroke, and lug 50 will be down and lug 52 up for an interval of time substantially equal to the length of time that flexible cable 36 is moving from the top to the bottom of its stroke.

In order to adjust my pressure control unit It! so that the amount of movement of lugs 53 and 52' above a horizontal center line through shaft 20'will .be exactly equal I merely loosen set screw 69 and turn circular head 66 until faces 10, and lzof my eccentric stop-lug 66. are equidistant from the; respective stop-pins l4 and 16. Another adjustment of eccentricstop-lugmay be made to cause one of the

lugs

50 and 52 to move farther above a horizontal line through the center of shaft 20 than the other lug.

I use the portion of my apparatus which I will hereinafter describe to measure the above two time intervals, and to readjust the balancing load on the reciprocating unit in accordance with that measurement.

A pair of two way air valves, I3 and 88 are affixed to the top of the pressure control unit housing I4 by means of a plate 82 which is afiixed to both of valves I8 and 80 and a bolt 84 which clamps valves I8 and 90 to the top of pressure control unit housing I4 by connecting said housing I4 and plate 82. It is to be understood that any other suitable means for attaching

valves

78 and 80 to housing I4 may be used.

Extending downwardly from

valves

78 and 80 are a pair of actuating stems 86 and 83, respectively, which are slideably mounted in a pair of

sleeves

90 and 92 that are inserted in

vertical passages

94 and 96 through housing I4.

My two-

way air valves

18 and 80 are similarly constructed, each being provided with a valve body 98 having a vertical bore I82 wherein a tubular valve element I02 is slideably mounted. Compression springs I04 are disposed within the upper portion of bores I80, being kept within bores I09 by contact with outlet port adapters I08 which contain two-way air ports I01 therein. Springs I04 abut against the tops of tubular valve elements I02 and urge elements I82 downward.

Threadedly mounted in the upper portions of adapters I06 are tubular bolts I88 which contain orifices I69 and III that are adapted to control the amount of air which is permitted to pass into and out of two-

way air valves

18 and 80, respectively.

When valve elements I92 are in their normal positions as shown in Figure 2, annular flanges III] in the upper portions of elements I82 are seated on valve seats II2 by the downward force from springs I84. I provide sealing rings I I4 between flanges IIO and valve seats I I2 to prevent air from passing therethrough when flanges I I0 are seated on valve seats H2.

Still considering the position of valve elements shown in Figure 2, lower faces H6 of valve elements I02 are in contact with upper faces IIB of actuating stems 86 and 83'. Sealing rings I20 are disposed between faces H6 and H8 to prevent air from passing between them when they are in contact.

By this arrangement, when my actuating stems 86 and 88 and my valve elements I02 are in the position shown in Figure 2, air will be blocked, by the seating of flanges III) on valve seats H2, from passing through

valves

18 and 80 by entering valves I8 and 80 at air pressure input points I22 and leaving

valves

18 and 80 at two-way air ports I01.

A further result of this position of stems 88 and valve elements I02 is that air will be blocked by the seating of faces H3 upon faces IIB, respectively, from passing through valves I8 and 80 by entering valves I8 and 89 at two-way air ports I01, passing lengthwise through tubular valve elements I02 and leaving valves I8 and 80 through bleeder passages I24.

When lug 50 is raised and lug 52 is lowered, in the manner heretofore described, my actuating stem 86 and its corresponding valve element I02 are raised, and my actuating stem 88 is lowered leaving its corresponding valve element I02 suspended, by engagement between annular flange H0 and valve seat H2, in the position shown in Figure 2. This will permit compressed air to flow into valve I8 through compressed air inlet port I 22, upward through vertical bore I00, between annular flange H0 and valve seat H2 and out of valve 78 through two-way air port I01 and orifice I09. Air will be prevented from leaving valve 18 through bleeder passage I24 by continuous engagement between face II8 of actuating stem 86 and face H6 of the corresponding valve element I02.

At .the same time, air will be prevented from flowing through valve from its air pressure input port I22 to its two-way air port I01 by en agement between flange H0 and seat II2 of valve 80. However, air will be permitted to bleed through valve 80 by entering valve 80 through orifice III and two-way air port I01, passing down through the center of tubular valve element I02, passing between face H8 or actuating stem 88 and face H6 of the corresponding valve element I02, and then passing out of valve 80 and into the atmosphere through bleeder passage I24.

Thus, when my shaft 20 is rotated counterclockwise in Figure 2, compressed air will pass out of valve I8 through its two-way port I01 and orifice I09 and air will pass into valve 80 through orifice III and its two-way port I01. Similarly, when shaft 20 is rotated clockwise in Figure 2, compressed air will ass into valve 78 through orifice I09 and its two-way port I01 and air will pass out of valve 80 through its two-way port I 01 and orifice III.

Compressed air may be provided at air pressure input ports I22 by a connection between ports I22 and any conventional source of air pressure. However, in the preferred embodiment of my invention in which my pneumatic time compensator is utilized in connection with an air balanced reciprocating system, main air Vessel I26 of the air balancing system is connected to pressure input ports I22 by means of a pressure line I28 which branches into a pair of lines I29. Since only a very low pressure is necessary to operate my time compensator, a pressure reducer I30 is interposed in line I28.

Having explained the operation of my pressure control unit I9, I will now describe my compensa tor unit I2. Compensator unit housing I6 comprises two preferably rectangular sections, I32 and I34, having laterally extending flanges I36 and I38 on their respective circumferences. Sections I32 and I34 are so relatively positioned that flanges I36 and I38 oppose each other, and sections I32 and I34 are clamped together by means of bolts I40.

Disposed on sections I32 and I34 of compensator unit housing I6 are tubular flanges I 42 and I44, respectively, which are centrally positioned in inter-opposing relationship on sections I 32 and I34 inside of the respective flanges I36 and I38.

Flanges I36 and I42 are connected at both the bottom and the top of section I32 by a centrally located vertical metal web I46, and similarly flanges I38 and I44 are connected at both the bottom and the top of section I34 by a centrally located metal web I48. Metal webs I46 and I48 are so disposed in sections I32 and I34 that they oppose each other.

When my compensator housing sections I32 and I34 are clamped together by bolts I40 to form the compensator housing I6 a central chamber I50 is formed inside of the tubular flanges I42 and I44. A second chamber, primary chamber I52, is formed to the right of metal webs I46 and I48 between flanges I42 and I44 on the inside and flanges I36 and I38 on the outside. A third chamber, primary chamber I54, is formed to the left of metal webs I46 and I48 between flanges I42 and I44 on the inside and flanges I36 and I38 on the outside.

I provide a sheet I 56 of pliable material which is clamped between compensator unit housing sections I32 and I34. Sheet I56 forms an air sealing gasket I58 between lateral flanges I36 and I38. A similar air sealing gasket I60 is formed by sheet I56 between tubular flanges I42 and I44. Sheet I56 is perforated as at I62, between flanges I42 and I44 on the inside and flanges I36 and I68 on the outside so that the right and left hand chambers I52 and I54, respectively, remain undivided.

The portion of sheet I56 which passes through central chamber I58 forms a flexible diaphragm I64 that bisects central chamber I58 into two secondary air chambers, I66 and I88, disposed respectively in housing sections I32 and I34.

Centrally mounted on my diaphragm I64 is a valve actuator I18 which comprises two portions, I12 and I14, that are clamped on opposite sides of diaphragm I64 by means of a bolt I16. The peripheries of the two portions I12 and I14 of actuator I18 are bevelled adjacent to diaphragm I64 to prevent injury to diaphragm I64 upon movement of the diaphragm due to a change in the relative air pressures of chambers I66 and I68. A plurality of stop-lugs I18. are formed on both sides of chamber I58 and extend inward toa front face I88 which is centrally positioned within chamber I 68 and which abuts against one end of a valve actuating stem I 82. Actuating stem I82 is utilized to actuate a two-way air valve I84 in much the same manner that my actuating stems 86 and 88 are used in connection with my

valves

18 and 80. Valve I84 is considerably more sensitive than

valve

18 and 88, so that movement of actuating stem I82 a small fraction of an inch will be sufiicient to operate valve I84.

My orifices I89 and II I, associated with

valves

18 and 88, respectively, are respectively connected to right and left hand primary chambers I52 and I54 through a pair of two-way air lines I86 and I88 and a pair of two-way ports I98.

During the half-cycle of operation of the reciprocating unit which is to be balanced when actuating stem 36 is up and actuating stem 88 is down, compressed air will flow from air vessel I26, through two-way air valve I8 in the manner heretofore explained, and hence into right-hand primary chamber I52 of the compressor unit through air line I86.

At the same time the two-way air valve 88 will permit air to flow into it and out at bleeder passage I24, whereby air will be permitted to bleed out. of left-hand primary chamber I54 through air line I88 and two-way air valve 88.

I provide a small orifice I92 between my left hand primary chamber I54, and my secondary chamber I66, and a corresponding small orifice I94 between my right-hand primary chamber I52 and my secondary chamber I68.

Thus, when air is permitted to flow into my right-hand primary chamber I52 by movement of actuating stem 86 to the upward position in the above manner, the resulting small increase of the pressure within right-hand primary chamber I52 will cause a corresponding even smaller increase in the pressure in secondary chamber I68 due to the passage of a small quantity of air through orifice I94.

Similarly, when air is simultaneously permitted to flow out of my left-hand primary chamber I54 by movement of actuating stem 88 to the downward position in the above manner, the resulting small decrease of the pressure within left-hand primary chamber I54 will cause a corresponding even smaller decrease in the pressure in secondary chamber I66 due to the passage of a small quantity of air through orifice I82.

By thus using my dual chamber system 0f having a pair of primary chambers I52 and I54 and a corresponding pair of secondary chambers I66 and I68, I minimize the pulsation factor at diaphragm I64. This is necessary in order to prevent constant oscillation of my actuator I18 and hence of my valve actuating stem I82.

Although the preferred embodiment of my invention has this dual chamber system, it is to be understood that my primary chambers I52 and I54 may be omitted and suitable results will still be obtained. However, if only a single pair of chambers, such as chambers I66 and I68, were used, these chambers I66 and I68 would have to be approximately 18 times as large as is necessary when I use both my primary and my secondary chambers.

Similarly, during the other half-cycle of operation of the reciprocating unit which is to be balanced, actuating stem 86 will be down, and actuating stem 88 will be up, whereby air will be admitted to primary and secondary chambers I54 and I66, respectively, and air will be exhausted from primary and secondary chambers I52 and I68, respectively.

The amount of air that is admitted to secondary chambers I66 and I68 during the respective half-cycles depends on the amount of pressure at air pressure input ports I22, the size of the orifices I89 and III in the two-way air lines I86 and I88, respectively, on the length of time that the

valves

16 and 88 permit air to flow to primary chambers I52 and I54, on the size of orifices I92 and I94, and the relative sizes of my primary and secondary chambers.

The air pressure supplied to air pressure input ports I22 is maintained at a substantially constant value by means of pressure reducer I38 in the preferred embodiment of my invention, and since the sizes of orifices I88 and I I I, and I92 and I84 remain constant, the only variable of the above factors is time.

Thus, if the half-cycles of operation of the reciprocating unit are of identical duration, two

way air valves

18 and 88 will admit air to the respective primary chambers I52 and I54 for the same time interval and they will also allow air to bleed out of the respective primary chambers I52 and I58 for the same time interval, whereby the .samepressure will be maintained within each of my primary chambers I52 and I54. In turn,

this causes equal pressures to be maintained in secondary chambers I86 and I68.

However, if the upward half-cycle of operation of the reciprocating unit is longer than the downward half-cycle, then two-way air valve 18 will admit compressed air to primary chamber I 52 for a longer portion of each complete cycle than two-way air valve 80 will admit compressed air to primary chamber I54, and also valve 18 will permit air to bleed out of primary chamber I52 for a lesser time than valve 80 will permit air to bled out of chamber I54. In turn, this will cause a gradual increase in the air pressure within secondary chamber I08 over the air pressure Within secondary chamber I68, whereby diaphragm I64 will move to the left in Figure 1. This causes actuator I to move to the left as an integral part of diaphragm I64 whereby front face I80 of actuator I18 will move away from valve actuating stem I82 to the left.

On the other hand, if the downward half-cycle of operation of the reciprocating unit is longer than the upward half-cycle, air valve 80 will admit compressed air to primary chamber I54 for a longer portion of each complete cycle than two-way air valve 18 will admit compressed air to primary chamber I52 and also valve 80 will permit air to bleed out of primary chamber I54 for a shorter period of time than valve 18 will permit air to bleed out of primary chamber I52. This will cause a gradual increase in the air pressure within primary chamber I54 over the air pressure within chamber I52, which in turn will cause a small increase in the air pressure within secondary chamber I 88 over the air pressure within secondary chamber I '68. This pressure differential between secondary chambers I88 and I68 will cause diaphragm I04 and actuator I10 to move to the right in Figure 1 so that valve actuating stem I82 will be permitted to move to the right.

Only a slight difference in the air pressures within secondary chambers I68 and I88 is necessary to cause actuation of valve actuating stem I82, but a suflicient difference in pressure is required so that merely momentary changes in the time required for the half-cycles of the reciprocating unit will not be sufficient to actuate valve I84. The time interval between the first instant the reciprocating unit becomes unbalanced and when valve I84 is actuated is determined by the pressure which is admitted to air pressure inlet valves I22 by the sizes of orifices I88, III, I92 and I84, by the relative sizes of my primary and secondary chambers, and by the diiference in pressure between secondary chambers I88 and I08 which is necessary order to actuate valve I84. Although the air pressure supplied at ports I22 is one of the variables which must be controlled, any suitable amount of pressure may be used which properly corresponds with the other factors such as sizes of my orifices.

The air pressure which I supply at ports I22 may be less than atmospheric pressure. A source of such a partial vacuum which is generally readily accessible is the intake manifold of a combustion engine. If the pressure at ports I22 is less than atmospheric pressure I cross my air lines I88 and I88 so that valve 18 is connected to primary and secondary chambers I54 and I68, respectively, and so that valve 80 is connected to primary and. secondary chambers I52 and I 88, respectively, This construction causes diaphragm I84 to move in the same direction as indicated 10 above for a corresponding movement of flexible cable 36.

Valve I84 functions similarly to

valves

18 and 80, but is considerably more sensitive to a small shift in the position of valve actuating stem I82 than valves 13 and are to movement of their respective actuating stems 86 and 88. The outer portion of valve I84 consists of a valve body I93 having a small cylindrical chamber I95 in its outer end to receive a coil spring I98 and a large cylindrical chamber I98 through most of its length which is adapted to receive the working parts of the valve.

The exposed end of spring I96 engages an annular flange 20!] of tubular valve element 202, the outer end of valve element 202 being disposed within the coils of spring I96.

Shank 284 of tubular valve element 202 is slideably mounted within a sleeve 206 which tightly fits in the inner portion of large cylindrical chamber I98. A sealing engagement is effected between sleeve 288 and chamber I98 by means of sealing rings 208.

Flange 200 of valve element 202 is urged into sealing engagement with valve seat 2 I0 provided at the outer end of sleeve 208 by means of the spring I96 when the actuating stem I82 is in the position shown in Figure 1. A sealing ring 2I2 completes the seal between flange 200 and seat 2H3. In this position of valve element 202, air will not pass through valve I84 in the usual manner by entering valve I84 at air pressure input port 2I4, passing through passages 2I6 in sleeve 208, passing along passage 2I8 provided by the reduced diameter of a portion of shank 204, passing between flange 280 and seat 2| 0 and then out of valve I84 through two-way air port 220.

Actuating stem I82 is slideably mounted within a sleeve 222 which is centrally disposed through compensator unit section I34. A sealing ring 224 is disposed between sleeve 222 and section I34. Stem I82 is urged toward actuator I10 by a coil spring 228, one end of spring 228 engaging a flanged portion 228 of stem I82 and the other end of spring 226 engaging a shoulder 230 in the end of sleeve 206. I

A sealing pad 232 is aflixed to the outer end of actuating stem I82 in order to provide a seat for the inner end 234 of tubular valve element 202, so that when the actuating stem I82 and valve element 202 are in the position shown in Figure 1, air will not be permitted to bleed through valve I84 by entering valve I84 through two-way air port 220, passing inward through the tubular valve element 282, passing between sealing pad 282 and end 284 of valve element 202 and then passing out of valve I84 into the atmosphere through passage 288, chamber 238 and clearance 240.

When my actuating stem I82 is moved to the right in Figure 1 by movement of my actuator I10, flange 280 will become spaced from seat 2I0, whereby air will be permitted to flow through valve I84 from air pressure input port 2I'4 to two-way air port 220. This air is conveyed to an unloader device 242 (see Figure 4) by means of an air line 244 whereby unloader 242 will be so actuated as to retain the balancing pressure at the value which it then has. t

On the other hand, when my actuator I10 is moved to the left in Figure l, actuating stem I82 will be moved to the left by the compression of coil spring 228 so that stem I82 will remain in engagement with surface I80 of actuator IIO. Although my spring I95 will prevent air from entering the system through air pressure input port 2T4, air pressure will be released from unloader 242 by being permitted to flow into valve I54 through line 244 and two-way air port 22c, through the center of tubular valve element 202, between sealing pad 232 and end 234 of valve element202, and then pass out of valve I84 into the atmosphere through passage 236, chamber 238 and clearance 240. By thus removing pressure from my unloader 242, the unloader will permit the balancing pressure to be raised.

It can thus be seen that whenever the upward half-cycle of the reciprocating unit becomes longer in duration than the downward half-cycle, which would be the case in an oil well pumping rig when the load becomes too heavy for the balancing pressure that is being used, pressure control unit I will provide more air to chamber 168 than to chamber I65 in compensator unit I2, whereby actuator I'II! will move to the left, so actuating my valve I84 that valve I84 will release pressure from unloader 242 to cause the balancing pressure to be raised.

However, whenever the reciprocating unit is in an overbalanced condition and the downward half-cycle of the reciprocating unit is longer in duration than the upward half-cycle, pressure control unit II) will provide more air to chamber IG'B than to chamber IE8, whereby actuator I? will move to the right, so actuating my valve I84 that valve I84 will apply pressure to unloader 242 to cause the balancing pressure to remain at the value which it then has.

Airpressure is supplied to port 2 I4 by mean of line 246 which is connected to pressure line I28 between reducer I30 and valves I8 and 80.

I provide a set pop valve 248 in line 244 between valve IM and unloader 242. Set pop valve 248 will dissipate or exhaust any excess balancing pressure from the pumping unit balancing system after a given interval of time has elapsed from the time of introduction of the additional pressure into the air balancing system in the manner described above. It will simultaneously keep suflicient air pressure from valve I84 exposed against un'loader 242 to maintain unloader 242 in proper operating condition.

The use of set pop valve 248 allows the air balancing system to be in an overbalanced condition, after pressure is released from unloader 242 through valve I84 because of a greater pressure inchamber I66 than in chamber I68, for a sufficient time to enable pressure control unit It to equalize the pressures within chambers I66 and I68. At this time actuator I'IQ will be in its central position, as illustrated in Figure 1, and set pop valve 248 will then automatically reduce the pressure in the balancing system to the properly balanced state. Pressure control unit III will thereafter merely maintain equal pressures within chambers I66 and I68, and valve 1 84 will remain in its normal position as shown in Figure 1.

During the normal use of my pneumatic time compensator in connection with a reciprocating unit I adjust eccentric stop lug 60 so that the reciprocating unit is substantially perfectly balanced. However, by proper adjustment of my eccentric stop-lug 60', I am able to compensate to any poundage over or under a perfect 'balance, within reasonable values. Thus, my pneumatic time compensator may be used for any 12 type of pumping wherein either a substantially perfect balance or an off balance is desired.

It is to be noted that although my preferred embodiment is used in connection with an air balanced reciprocating unit, it can be connected with a system which is balanced by other means than air, such as a pumping system which is balanced by moveable weights.

Further, it is to be understood that other devices can be used in place of my two-way air valve I84 for enabling unloader device 242 to be actuated by movements of actuating stem I82. For example, in certain applications of my invention wherein it may be advantageous to use electricity instead of air as the secondary actuating medium, it would be a simple matter for one skilled in the art to substitute an electric make and break contact device for two-way air valve I84 whereby a clutch could be moved into and out of engagement, in turn causing an air compressor to supply and discharge air respectively precisely in the same way that my two-way air valve I84 supplies and discharges air.

It is also to be understood that any suitable dual, two-way air valve system and associated operating mechanism may be utilized in place of my preferred pressure control unit In without departing from my present invention.

The simplicity, accuracy and compactness of my invention contribute to make it a highly useful and desirable commercial item.

It is to be understood that the form of my invention herein shown and described is my preferred embodiment and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention, or the scope of the appended claims.

I claim:

1. A pneumatic time compensator for a reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure control unit, a compensator unit, an air pressure connection between said pressure control unit and said compensator unit and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

2. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said valves, a compensator unit, an air pressure connection between each of said valves and said compensator unit and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

3. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves actuated by synchronous reciprocal motion from said machine, each of said air valves having an input port, an output passage and a two-way port, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said input ports, a compensator unit, an air pressure connection between each of said two-way ports and said compensator unit and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

4. A pneumatic time compensator for a reciprocating machine including a pressure control unit actuated b synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pres sure control unit, a compensator unit including a pair of pressure chambers, an air pressure connection between said pressure control unit and each of said chambers and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

5. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said valves, a compensator unit including a pair of pressure chambers, air pressure connections between said.

valves and said pressure chambers, respectively, and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

6. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves actuated by synchronous reciprocal motion from said machine, each of said air valves having an input port, an output passage and a two-way port, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said input ports, a compensator unit including a pair of pressure chambers, air pressure connections between said twoway ports and said chambers, respectively, and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

7. A pneumatic time compensator for a reciprocating machine including a pressure control unit actuated b synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure contro1 unit, a compensator unit including a pair of pressure chambers, an air pressure connection between said pressure control unit and each of said chambers, a pressure diiierential responsive member separating said pressure chambers and an output member on said come pensator unit operatively connected to said pres sure differential responsive member, said output member being operatively connectable to means for balancing said machine.

8. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said valves, a compensator unit including a pair of pressure chambers, air pressure connections between said valves and said pressure chambers, respectively, a pressure differential responsive member separating said pressure chambers and an. output mem-- ber on said compensator unit operatively connected to said pressure difierential responsive member, said output member being operatively connectable to means for balancing said machine. 9. A pneumatic time compensator for a recip.-'

til

ro'cating machine including a' pressure control unit actuated by synchronous motion from said machine, asubstantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure control unit,

a compensator unit including a pair of pressure" chambers, an air pressure connection between said pressure control unit and each of said chambers, a diaphragm separating said pair of pressure chambers and an output member on said compensator unit operatively connected to said diaphragm, said output member bein operatively connectable to means for balancing said machine.

10. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves, each of which is operably connected to an air valve actuating stem, the respective said actuating stem being operatively connectable, by means of a pair of operative connections having a substantially 180 degree relative phase diiierence, to a reciprocating member of said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said valves, 2, compensator unit, an air pressure connection between each of said valves and said compensator unit and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

11. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves, each of which is operably connected to an air valve actuating stem, the respective said actuating stems being operatively connectable, by means of a pair of operative connections having a substantially 180 degree relative phase difference, to a reciprocating member of said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said valves, a compensator unit including a pair of pressure chambers, air pressure connections between said valves and said pres sure chambers, respectively, and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

'12. A pneumatic time compensator for a reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure control unit, a compensator unit including a pair of primary pressure chambers, each of which is pneumatically connected to a respective secondary pressure chamber, an air pressure connection between said pressure control unit and each of said primary chambers and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

13. A pneumatic time compensator for a recip rocating machine comprising a pressure control unit including a pair of air valves actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and each of said valves,

a compensator unit including a pair of primary pressure chambers, each of which is pneumatically connected to a respective secondary pres sure chamber, air pressure connections between said valves and said primary chambers, respec tively, and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

14. A pneumatic time compensator for a reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure control unit, a compensator unit including a pair of primary pressure chambers, each of which is pneumatically connected to a respective secondary pressure chamber, an air pressure connection between said pressure control unit and each of said primary chambers, a pressure differential responsive member separating said secondary pressure chambers and an output member on said compensator unit operatively connected to said pressure differential responsive member, said output member being operatively connectable to means for balancing said machine.

15. A pneumatic time compensator for a reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure control unit, a compensator unit including a pair of primary pressure chambers, each of which is pneumatically connected to a respective secondary pressure chamber, an air pressure connection between said pressure control unit and each of said primary chambers, a diaphragm separating said secondary pressure chambers and an output member on said compensator unit operatively connected to said diaphragm, said output member being operatively connectable to means for balancing said machine.

16. A pneumatic time compensator for an air balanced reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of controlling air pressure connected to said pressure control unit, a compensator unit, an air pressure connection between said pressure control unit and said compensator unit, and an output member on said compensator unit consisting of a two-Way air valve.

17. A pneumatic time compensator for an air balanced reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of controlling air pressure connected to said pressure control unit, a compensator unit including a pair of pressure chambers, an air pressure connection between said pressure control unit and each of said chambers, a pressure differential responsive member separating said pressure chambers, an output member on said compensator unit consisting of a two-way air valve, and an operative connection between said pressure differential responsive member and said two-way air valve.

18. A pneumatic time compensator for an air balanced reciprocating machine including a pressure control unit actuated by synchronous reciprocal motion from said machine, a substantially constant source of controlling air pressure connected to said pressure control unit, a compensator unit, an air pressure connection between said pressure control unit and said compensator unit, an'output member on said compensator unit consisting of a two-way air valve, an unloader device operatively connectable .to

air balancing'means for balancing said machine, a source of unloader air pressure connected to said two-way air valve and an air connection between said two-way air valve and said unloader device.

19. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves, each of which is operably connected to an air valve actuating stem, an alternately rotating shaft mounted in said pressure control unit and alternately rotated by synchronous reciprocal motion from said reciprocating machine, a pair of reciprocally mounted lugs mechanically interconnecting said shaft and the respective said actuating stems, a substantially constant source of air pressure, an air pressure connection between said source of pressure and said pressure control unit, a compensator unit, an air pressure connection between each of said valves and said compensator unit and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

20. A pneumatic time compensator for a reciprocating machine comprising a pressure control unit including a pair of air valves, each of which is operably connected to an air valve actuating stem, an alternately rotating shaft mounted in said pressure control unit and alternately rotated by synchronous reciprocal motion from said reciprocating machine, a lug carrier r0- tatably mounted substantially concentrically with said shaft, a clutch connection between said shaft and said lug carrier to permit said shaft to oscillate at a greater amplitude than said lug carrier, a pair of lugs mounted on said lug carrier, an operative connection between said lugs and the respective said actuating stems, a substantially constant source of air pressure, anair pressure connection between said source of pressure and said pressure control unit, a compensator unit, an air pressure connection between each of said valves and said compensator unit and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

21. A pneumatic time compensator for a reciprocating machine including a compensator unit, a substantially constant source of air pressure, means for alternately connecting said source of pressure to said compensator unit for substantially the time periods of the respective half cycles of the reciprocal motion of said machine, and an output member on said compensating unit which is operatively connectable to means for balancing said machine.

22. A pneumatic time compensator for a reciprocating machine comprising a compensator unit including a pair of pressure chambers, a substantially constant source of air pressure. means for alternately connecting said source of pressure to the respective said chambers for substantially the time periods of the respective half cycles of the reciprocal motion of said machine, and an output member on said compensator unit which is operatively connectable to means for balancing said machine.

23. A pneumatic time compensator for a reciprocating machine comprising a compensator unit including a pair of pressure chambers, a substantially constant source of air pressure, means for simultaneously connecting said source of pressure to one of said chambers and opening a bleed passage from the other of said chambers to the atmosphere for substantially the time 17 18 period of one half cycle of the reciprocal motion of said machine and for simultaneously connect- References Cited in the file Of this patent ing said source of pressure to said last men- UNITED STATES PATENTS tioned chamber and opening a bleed passage from said first mentioned chamber to the atmosphere 5 Number Name Date for substantially the time period of the other g ff g half cycle of the reciprocal motion of said ma- 2269787 g g e g 1942 chine, and an output member on said compen- 2,432,735 Downing Dec. 16, 1947 sator unit which is operatively connectable to means for balancing said machine.

EDGAR W. PATTERSON.