US3152611A - Pneumatic timer system - Google Patents

Description

Oct. 13, 1964 L. M. HUBBY PNEUMATIC TIMER SYSTEM Filed Aug. 14. 1962 United States Patent Office 3,152,611 Patented Oct. 13, 1964 3,152,611 PNEUMATIC TIMER SYSTEM Laurence M. Hubby, Bellaire, Tex., assignor to Texaco Inc., New York, N.Y., a corporation of Delaware Filed Aug. 14, 1962, Ser. No. 216,836 7 (Ilaims. (Cl. 137-62414) This invention is concerned with a pneumatic timer generally and more specifically concerns an improved pneumatic timer arrangement that is especially adapted for use with gas lift wells or the like.

Heretofore it has been generally the practice in connection with gas lift oil well pumping operations, to employ a timer for each well that regulates the length of time during which gas under pressure is admitted to the annulus of the well that is being gas lifted. The gas lift operation (which is well known) involves intermittent introduction of gas under pressure to the annulus of the well which is closed at the top and bottom thereof. Such gas pressure, when it is introduced enters the tubing through gas lift valves and causes accumulated fluids, e.g. oil, to be driven up out of the well through the tubing. Each lifting cycle is arranged in its time duration to lift all of the accumulated liquid each time gas pressure is applied. Then the intervening time period which fol lows each application of the pressurized gas, allows time for the producing liquid to accumulate downhole in the tubing ready for the next so-called gas lift cycle.

As indicated previously, the timing control for gas lift pumping operations has heretofore most frequently been one that is basically clock work control. This prior arrangement involved a pilot valve action which in turn would control the application of pneumatic pressure to the main control valve for applying gas pressure to the well. Such prior arrangement had various drawbacks including the fact that the clock work control was relatively delicate in nature, so that rough handling would often necessitate repairs. Furthermore, since such operations are most often in isolated areas, the clock work must of necessity have been a spring wound type. Consequently there was a periodic requirement for winding the clock work, to maintain the gas lift operation. In addition such clock work controls were relatively expensive equipment. Also,

' clock work type of controls are not adaptable to remote control operations, nor are they amenable to continuously synchronizing the wells in a given oil field.

Thus, although it is known to employ fluid in a timing arrangement, such known arrangement involves as a principal control element one that includes a snap acting valve structure. Such valve structure is one that involves mechanical shifting of a rotatable element therein, and consequently the arrangement is subject to constant wear and thus relatively short life, or subject to frequent repairs. Finally, it is not apparent that such prior arrange ment could be adapted for use in remote control arrangements such as is the case with the subject invention.

Consequently it is an object of this invention to provide a pneumatically powered, timing system that is relatively simple and rugged in its construction.

Another object of the invention is to provide a fluid timer system that is accurate and positive acting while being simple and inexpensive in construction.

Another object of the invention is to provide a pneumatic timing arrangement that is self-actuating, reliable and is readily adaptable for remote control type of operation which includes arrangements for maintaining exact synchronous relationship between a plurality of timers in a given oil field.

Briefly, the invention concerns a pneumtic timer system which comprises means for receiving compressed gas. The system also comprises a first container, a second container and a fluid path connecting said first and second containers and including two branches. In the foregoing system, each branch includes therein a restriction and a check valve in series. The system also comprises a quantity of liquid in said containers, said liquid quantity having a maximum volume that is equal to the smaller of said containers in order to permit flow of some gas through said fluid path following flow of said liquid therethrough. In addition the system comprises a fluid pressure operated three-way valve having an operator, and pneumatic circuit means connecting one of said containers to the operator of said three-way valve and the other of said containers to said three-way valve for alternative connection to said receiving means or to exhaust, whereby introduction of a compressed gas into the system causes said liquid to flow from said first container into said second container and return in a cyclic manner.

Again briefly, the invention relates to a system in combination with a gas lift type pump including a source of gas under pressure, and a pressure operated control valve. In the foregoing system the invention concerns the improvement that comprises a pneumatic timer for controlling actuation of said pressure operated control valve wherein said timer comprises means for connecting the source of gas under pressure to said timer system. The improvement also comprises a first container for receiving said gas under pressure, a second container, and a fluid path interconnecting said first and said second containers and having two branches. The foregoing branches each contain a restriction and a check valve in series therewith. The improved system also comprises a quantity of liquid freely held in said containers in direct contact with said gas. The said liquid quantity has a maximum volume that is equal to the capacity of the smaller of said containers. The improved system additionally comprisesa fluid pressure operated three-way valve having an operator for actuation thereof, and pneumatic circuit means for connecting said source of gas under pressure to said three-way valve and from said three-way valve to said first container. In addition the improved system comprises additional pneumatic circuit means for connecting said second container to the operator of said three-Way valve and to said control valve, all whereby a continuous cyclic operation takes place causing said control valve to be intermittently opened and closed to introduce into said well predetermined pumping quantities of gas under pressure.

The foregoing and other objects and benefits of the invention will be more fully appreciated in connection with the detailed description which follows, and which is illustrated in the drawing, in which:

The figure of drawing shows a schematic system diagram, illustrating a timer according to the invention as connected to a gas lift well.

Referring to the figure of the drawings there is illustrated a gas lift well 11 that is closed at the top as indicated, and carries therein tubing 12 that extends downhole to the producing formation and includes gas lift valves (not shown) spaced at intervals along its length and a packer (not shown) near the bottom to seal the annulus from the tubing. The tubing 12 acts to accumulate production fluid that is then discharged upward through tubing 12 when application of gas under pressure is introduced into the tubing from the annulus of the well 11 surrounding the tubing. The gas under pressure for causing such gas lift pumping operation is introduced via a pipe 13 that is connected to the well 11 and that carries in series therewith a main control valve 14, shown schematically in the drawing. The gas under pressure that is delivered through valve 14 and pipe 13 is drawn from a source of relatively high pressure, e.g. a compressor (not shown), and is introduced through another pipe 17 that is connected to the other end of the valve 14. This gas under pressure may be termed power gas as indicated by the caption on the drawing. Ordinarily such gas will be a large volume source of pressured gas, under relatively high pressure, e.g. 600 pounds per square inch.

The timer system per se is illustrated schematically at the left hand portion of the figure of drawings and is shown enclosed in a dashed line box 18. The elements included in this system are connected with a source of pneumatic pressure which in the illustrated arrangement includes a pneumatic line 21 that joins the power gas pipe 17 and leads to a pressure regulator 22. Pressure regulator 22 reduces the pressure in the pneumatic line at the output side thereof. The output side is connected via a pneumatic line 23 that leads to one port of a threeway valve 24. Three-way valve 24 is a fluid pressure operated type, and as schematically illustrated has a diaphragm actuator 29 that is mechanically connected to the valve elements (not shown) that control pneumatic flow paths including two other ports. One of these ports leads to exhaust over a pneumatic line 30 while the other is connected to a pneumatic line 31 that leads to the upper interior volume of a container 32. There is another container 33 that may have greater volume interior space than container 32, and that has connected to the upper portion of the interior thereof a short pneumatic line 34 which branches into two separate pneumatic lines 35 and 36. Pneumatic line 35 leads to a pneumatic pressure actuator element 39 of the valve 14, while line 36 leads through a restriction 40 to a volume tank 41. Also connected to volume tank 41 there is another pneumatic line 44 which leads to the diaphragm actuator 29 of three-way valve 24.

From the bottoms of containers 32 and 33 there are fluid line circuit connections which include two paths 47 and 48, that join together and provide a common path 49 that is in turn connected into the bottom of the container 33. In each of the paths 47 and 48 (in series therewith) there is a restriction 51 and 52 respectively. The restrictions are schematically illustrated, but may take the form of needle valves in order to provide for adjustment thereof. In addition to the restrictions, there is a check valve 54 and 54 respectively in each of the flow paths 47 and 48. These check valves are oriented to permit flow only in opposite directions through the two paths.

There is a quantity of liquid 60 that may be hydraulic fluid, e.g. oil (as per the caption). This liquid 60 is situated in one or the other or both of the containers 32 and 33. The amount of liquid 60 is predetermined such that the total maximum volume thereof is not greater than the internal volume of the smaller of the containers 32 or 33. The reason for this quantity limitation will become clear below, in connection with a description of the operation.

Operation The operation of the pneumatic timer may be described by following the action of the liquid 60 in the system, as it is shifted back and forth between containers 32 and 33. It is to be observed that this liquid is freely situated within the contaners, so that the pneumatic pressure which is applied to the containers brings the compressed gas directly into contact with the surface of the liquid. Also, the main control valve 14 is normally closed, i.e. it is biased to a closed position.

A cycle of timing operation may be followed by observing the action created as the power gas in pipe 17 applies pneumatic pressure over pneumatic line 21 and through pneumatic regulator 22 to pneumatic line 23 that is connected to an input port of the three-way valve 24. Valve 24 is constructed such that it takes up as its normal state (e.g. by means of a spring bias) the condition such that the input port (to which line 23 is connected) is open through to the output port that is connected to pneumatic line 31, which leads to container 32. Consequently, so long as the three-way valve 24 is in its normal state, the

pneumatic fluid under pressure will enter the upper portion of container 32 and apply pressure to the liquid 60 within container 32 thus causing the liquid to flow over path 47 (via restriction 51 and check valve 53) to the fluid line 49 that leads into the bottom of container 33. Therefore liquid 60 will flow from container 32 into container 33 at a rate determined by the opening of the restriction 51. During this liquid flow the gas within container 33 will be gradually compressed somewhat, which compression will be transferred via pneumatic lines 34 and 35 to the pneumatic actuator 39 of the main valve 14. However, this pressure change will be slow and will be insufficient to cause enough pressure change for actuation of main valve 14 during such liquid flow.

When liquid 60 has all flown out of container 32 and past restriction 51, the flow of pneumatic fluid through restriction 51 will be rapid compared to the flow of the liquid and consequently the rate of flow of the liquid will suddenly be greatly increased. This rapid increase in flow of liquid 60 will compress the gas in container 33 and in the pneumatic lines connected thereto, so that a suflicient increase in pressure will be applied to the actuator element 39 of valve 14 so as to open the valve. This, of course, will allow power gas to enter the well 11.

Shortly after the actuation of valve 14 by its pneumatic actuator 39, the same rapid increase of pneumatic pressure (existing above the liquid 60) in the chamber 33 will cause a delayed pressure increase via restriction 40 and pneumatic line 36 as well as the volume tank 41 and pneumatic line 44, to act on the diaphragm actuator 29 of three-way valve 24. This increase in pressure will then cause three-way valve 24 to be actuated from the normal state described above to its other state, such that the input port to which line 23 is connected will be closed While the output port that is connected to line 31 will be connected to exhaust via pneumatic line 30. When this delayed action takes place, the three-way valve 24 will cut off the pneumatic pressure source to the system and simultaneously will connect the upper portion of (gas within) container 32 directly to exhaust. Consequently as the gas is exhausted out of container 32, the liquid 60 will be forced back by reason of the gas under pressure contained above the liquid in container 33.

The return liquid flow will take place via fluid path 49 and path 48 in this instance, by reason of the orientation of check valve 53 which is closed to this direction of fluid flow while check valve 54 is open to permit such flow. In this instance the rate of flow of the liquid as it returns from container 33 back into container 32, will be controlled by the size of the opening created in restriction 52. Once again (in this return fiow portion of the total cycle) the liquid flow will be relatively slow so that gas pressure above the liquid in container 33 and pneumatic lines connected thereto, will remain relatively constant having only a slow reduction. Thus, suflicient pressure will remain to maintain valve 14 open and three-way valve 24 actuated (under pressure) to the last position just described above.

Finally, when the last of liquid 60 flows out of container 33 and past restriction 52, the gas flow past restriction 52 will be at an increased rate by reason of the lower viscosity of the gas, and consequently the pressure in container 33 and connecting lines will be rapidly reduced. Such rapid reduction of pressure will cause the valve 14 to close positively, as the pressure in its actuator 39 drops, while shortly thereafter three-way valve 24 will return (also with positive action) to its normal state by reason of the pressure reduction within actuator 29 thereof. Thus the system is once more returned to its original state and another complete cycle such as that just described, will commence once more.

It will be observed that the continuously repeating cyclesof operation (causing opening and closing of the main valve 14) will automatically take place at any predetermined time duration intervals. Such intervals will be determined by the various factors such as the volume of liquid, the size of openings in restrictions 51, 52 and the viscosity of the liquid dtl, etc. Furthermore it will be noted that the open and closed time periods for valve 14, may be separately adjusted by individual regulation of the restrictions 51 and 52.

It is pointed out that the various elements such as restrictions 51, 52 and 46 as well as three-way valve 24 and check valves 53, 54 etc., are all shown schematically, since any feasible elements may be employed from among those commercially available in the field of pneumatic and liquid flow equipment.

As will be observed in connection with a copending application, a pneumatic timing system according to this invention is readily adaptable for interconnection with like units so as to provide for synchronous operations that cannot get out of step. Furthermore, the timers of this invention are adaptable for remote control arrangements, e.g. such as the one illustrated in the aforementioned copending application.

While a preferred embodiment of the invention has been shown and described in considerable detail in accordance with the applicable statutes, this is not to be taken as in any way limiting the invention but merely as being descriptive thereof.

I claim:

1. A pneumatic timer system comprising means for receiving compressed gas to energize said system, a first container, a second container, a fluid path connecting said first and second containers and including two branches, each branch including therein a restriction and a check valve in series, said check valves being oriented to permit flow in opposite directions, a quantity of liquid in said containers, said liquid quantity having a maximum volume equal to the smaller of said containers in order to permit flow of some gas through said fluid path following flow of said liquid therethrough, a fluid pressure operated three-way valve having an operator and three ports, one of said ports being connected to exhaust, another of said ports being connected to said receiving means, and pneumatic circuit means connecting one of said containers to the operator of said three-way valve and the other of said containers to said third port of said three-way valve for alternative connection thereof to said receiving means or to exhaust whereby introduction of a compressed gas into the system through said receiving means causes said liquid to flow from said first container into said second container and return in a cyclic manner.

2. A pneumatic timer according to claim 1 wherein 6 said one container is connected to a pressure operated output element for actuation thereof upon increase of pressure.

3. A pneumatic timer according to claim 2 wherein said restrictions are adjustable for providing dififerent time duration of the portions of a complete cycle.

4. A pneumatic timer according to claim 3 further including a volume tank and an additional restriction in series in said circuit means between said one container and the operator of said three-way valve, to ensure positive action of said output element.

5. A pneumatic timer for controlling actuation of a pressure operated control valve comprising input means for connecting a source of gas under pressure to said timer, a first container for receiving controllably said gas under pressure, a second container, a tiuid path interconnecting said first and second containers and having two branches, said branches each containing a restriction and a check valve in series therewith, said check valves being oriented to permit flow in opposite directions, a quantity of liquid freely held in said containers in direct contact with said gas, said liquid quantity having a maximum volume equal to the capacity of the smaller of said containers, a fluid pressure operated three-way valve having an operator for actuation thereof and having three ports, one of said ports being connected to exhaust, another of said ports being connected to said input means, and pneumatic circuit means for connecting said third port to said first container, and additional pneumatic circuit means for connecting said second container to the operator of said three-way valve and to said control valve, said three-way valve being constructed and arranged for alternately connecting said first container to said input means and to said exhaust means, all whereby a continuous cyclic operation takes place upon application of said gas under pressure causing said control valve to be intermittently opened and closed.

6. The improvement according to claim 5 wherein said restrictions are adjustable to regulate the time of the corresponding portion of the cycle.

7. The improvement according to claim 6 wherein said additional pneumatic circuit means includes a volume tank and a restriction in the connection from said second container to the operator for delaying actuation of said three-way valve relative to said control valve.

Kain Jan. 1, 1952 Canalizo Apr. 10, 1962

Claims (1)

1. A PNEUMATIC TIMER SYSTEM COMPRISING MEANS FOR RECEIVING COMPRESSED GAS TO ENERGIZE SAID SYSTEM, A FIRST CONTAINER, A SECOND CONTAINER, A FLUID PATH CONNECTING SAID FIRST AND SECOND CONTAINERS AND INCLUDING TWO BRANCHES, EACH BRANCH INCLUDING THEREIN A RESTRICTION AND A CHECK VALVE IN SERIES, SAID CHECK VALVE BEING ORIENTED TO PERMIT FLOW IN OPPOSITE DIRECTIONS, A QUANTITY OF LIQUID IN SAID CONTAINERS, SAID LIQUID QUANTITY HAVING A MAXIMUM VOLUME EQUAL TO THE SMALLER OF SAID CONTAINERS IN ORDER TO PERMIT FLOW OF SOME GAS THROUGH SAID FLUID PATH FOLLOWING FLOW OF SAID LIQUID THERETHROUGH, A FLUID PRESSURE OPERATED THREE-WAY VALVE HAVING AN OPERATOR AND THREE PORTS, ONE OF SAID PORTS BEING CONNECTED TO EXHAUST, AN-

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