US2072435A - Flow valve - Google Patents

Description

J. w. TAYLOR March 2, 1937.

FLOW VALVE Filed DSC. 1l, 1933 l F i5 5.

:l m/nh* JCHTIQW Ia-BUCK @im 6M www Patented` Mar.. 2, 1937 OFFICE FLOW V4 James W. Taylor, San Antonio, Tex. Application lllecember lll, i933, Serial No. M393 t crains.

l the pressure Huid is obtained directly from thewellor where itis forced into the well by articial pressure.

lt is an object of the invention to provide a structure which will not be clogged by parafn l or similar residue from the Well accumulating on the interior of the casing or on the upper surface of the liquid. Foreign matter, such as fragments of canvas or other packers and foreign material falling into the well, is frequently found iloating on the surface of the liquid and tends to be carried into the valve when the liquid level reaches the level of the opening through the valve. I contemplate keeping the valve closed until the liquid level has passed below the valve.

I also contemplate so forming the inlet to the eduction tube that foreign matter settling in the tube will not clog the inlet opening from the valve to the tube.

I desire to provide a valve so constructed that its openingand closing differentials will not necessarily be the same so that the valve will open at different differential pressures than those at which it closes.

I desire toprovide a @w valve which will remain closed where the liquid level has been lowered to a point adjacent the lower end of the tube and will not open to waste gas during the operation of the device.

Referring to the drawing herewith, Fig. 1 is a central longitudinal section through one of the couplings employed in the eduction tube, the

coupling being equipped with my improved device.

Fig. 2 is an assembly view showing the well casing and the eduction tube in central longitudinal section.

Fig. 3 is a transverse section on the plane 3-3 of Fig. 1.

I have shown somewhat diagrammatically a Well casing l having at its upper end a casing head 2 with a lateral inlet pipe 2li thereon through which fluid under pressure may enter into the well. The eduction tube |18 is to be 55 understood asv having a fluid tight fit through (lUll. 303-233) the upper end of the casing head so that there will be nofescape around the tube and above the inlet t0 for ai'r. v

Along the tube at different levels thereon I introduce special tubing couplings 3, said cou- 5 plings being made with an interior thread t at the upper end and an exterior thread 5 at the lower end for connecting in the pump tube l0. At one side oi the Vcoupling is rigidly xed a valve housing t. l0

rli'he valve housing 6 is made of any suitable lmaterial and securely welded to the exterior oi."l

the body as shown. In the housing'is a valve member ll, which shuts olf communication between the casing and tubing when it moves into it the outlet 8 at the upper end of the housing. At its lower end, or bottom, the housing is closed to gas'entry upwardly from that end by the plug il in the upper end of which a seat l0 is iorrned. The numeral ll indicates a lateral gas entry, 20 which is placed in this position in order to prevent the forcing of paraffin and the like into the valve housing when the device is being lowered into the well. It will be noted that the outlet 0 is so formed at its terminus as to divert gas 25 ow through the valve housing downwardly as it passed into the flow pipe. This feature is to prevent the settling of sediment in the sub-s merged valves when the well is being flowed from higher levels. For example, if thewell is being 30 flowed through valve I6, Fig. 2, sediment carried by the liquid would settle back into valve ll where the outlet pointed upwardly or even horizontally. But experience has shown that with the outlet turned in a downwardly direction no 35 trouble from this source is experienced.

In considering the construction vof my valve certain factors must be considered. For instance, where a spring is used to hold it open, as has previously been the case in most similar devices, 40 the pressure at which the valve closes will in every case also be the pressure at which it opens.

If the valve does not close until the pressure in the flow line is less by fifty pounds than the. casing pressure, then it will open as soon as the 45 pressure is again equalized within fty pounds. Valves of this type operate fairly well where a large amount of liquid is being moved rapidly from the Well under high pressure. However, once the liquid in the casing has been discharged and the operating fluid begins to escape from the well by entering the lower end of the flow pipe the pressure between the casing and the flow line becomes so near equalized that the spring actuated valve `opens and permits the gas to escape from the casing to the iiow line through the upper valve.

For example, in Fig. 2, when the resistance to 'flow from the bottom of the tubing I9 to the lowermost valve I1 becomes less than the spring pressure of the valve, then the valve opens; and when the lowermost valve opens and begins to admit gas to the tubing it soon brings the next valve above within range of its differential pressure and causes it to open. And this follows up until all valves open, which results in a heavy loss of the operating fluid.

From the foregoing, it will be seen that, while it is desirable to have the valve remain open until a comparatively high pressure differential has been established between the casing and tubing, it is necessary to hold the pressure at which the valve opens safely below the resistance offered to flow by the tubing between valves, under any and all conditions.

'Ihere are four factors that enter into the operation of the valve: 'I'he weight of the member 1, Fig. 1, the contours of its upper and lower ends I2 and I3, the areas of the outlet 8 and the lower seat I0. With the valve a given weight, the smaller the outlet 8, the higher will be the opening differential pressure after the valve is in its upper seat; and the larger the seat IU, the lower will be the pressure required to lift the member 1 from the seat I0 and admit gas to the chamber 6.

With the member 1 resting on the seat I0, it is plain that a certain excess of pressure must be applied through the inlet I I over that in the tube and above the valve before the member would leave the sat I0 and admit gas to the interior of the chamber 6; this will be called pick-up differential. The pressure at which the valve shuts 01T gas iiow by being carried to the upper seat 8, will be called closing differential, and the pressure at which it drops by gravity from the seat 8 to admit gas to the tubing will be called opening differential.

'I'he opening differential is determined by dividing the weight, in pounds, of the member 1 by the area, in square inches, of the outlet 8. The pick-up differential, the pressure required to lift the member 1 from the seat I0 to admit gas to the housing, is determined by dividing the weight of the member 1 by the area of the seat I 0. lThe closing differential is determined by the taper of the head I3 on the member 1.

Thus it will be seen that the valve may be varied and controlled by the use of my invention with an exactness heretofore not found in devices of this character. Also it has been found that the gas inlets must be proportioned to the size of the tubing, i. e., the inlets must increase or decrease in the same ratio as does the crosssectional area of the tubing. For if the gas entry be too large, the volume of gas entering the tubing will set up a resistance so great in the pipe above the valve that the latter will not shut off ow, for the reason that the pressure differential necessary to its closing cannot be established. The greater the depth, the greater the gas pressure necessary to flow the well. Increased pressure means increased density; and increased density means increased iiow through a given size orifice, even though the pressure differential remains the same. In other words, it is necessary that the volume of operating fluid flowing through the valve under any and all conditions be known, at least to a reasonable degl?? 0f Cel'- tainty; and this is easily arrived at when the correct formula is used.

Fig. 2 represents the well being flowed by admitting compressed air or gas to the casing I4 through the pipe 20. The liquid has been lowered in the casing to a -point below the lowermost valve I1. The upper valve I5 has closed due to the fact that the pressure in the flow line at this point has become less, by the closing differenital pressure of the valve, than the pressure in the casing. Member I6 is in operation and the well is flowing from this point.

Valve I'I has not yet opened from below t0 admit gas to the housing, for the reason that the casing pressure and the pressure inthe tubing are too nearly equal at this point for the valve 1 to be raised from the seat I0 at the instant the gas reaches it. For the weight of the valve 'I is concentrated on the seat I0; the weight of the liquid in the tubing, plus the resistance set up by the gas flowing through member I6, are all pressing back against the valve 1 to hold it against the seat I0 and prevent flow through the valve housing. This means that the valve 1 will not move off the seat I0 until the liquid in the casing has reached a level several feet below the valve.

Thus, by the valves remaining closed to flow un til the liquid has passed the entry II, floating foreign matter does not flnd its way into the housing but is forced around the lower end of the tubing and out of the well. By regulating the inlet and the outlet from each valve and the taper on the end of thevalve, I am enabled to obtain accurate perfomance so that no gas will be wasted.

When in operation, the valves automatically close as the liquid islowered in the well. Should the well be emptied to a point where the air or gas enters with the liquid at the bottom of the tubing, then all valves will have closed and will remain so as long as the well is flowed from this point. It will be seen, however, that if for any reason the liquid should rise in the Well to a point where the gas would be shut off from entering the lower end of the flow line, flow would cease. But as soon as the liquid coming into the well rises in the tubingi to within a predetermined distance of` the lowermost valve, said valve will open by gravity and admit gas to the tubing to continue the flow. And what applies to one valve applies to all valves.

Where it is desired to limit the flow. the well may be'flowed from any point where a valve is located, by merely restricting the volume of operating fluid entering the casing.

The extreme simplicity and durability of the present invention as a whole will be noted. There are no springs or small parts to get out of order, it is easily and cheaply manufactured, and has proved remarkably eicient in use. It adapts itself to regulation as to opening and closing differentials so that waste of pressure fluid may be avoided.

Having described the invention, what I claim 1s:

1. A ow valve for well tubing including a tubular body having a female thread in the upper end adapted to engage the tubing thread, a male thread on the lower end thereof adapted to engage the tubing coupling, a valve housing attached vertically to the exterior of said body, an entry in the side wall at the lower end of said housing, an outlet in the upper end thereof, said outlet terminating in a downwardly directed passage into said body, valve seats in said entry and said outlet, and a valve disposed between said inlet and outlet vto engage either` of said seats to control the flow of fluid therethrough.

2. A ow valve for well tubing including a tubular body,- a valve housing attached vertically to the exterior of said body, a lateral entry adjacent the lower end of said.l housing, anoutlet to said body at the upper end thereon a gravity operated valve of predetermined'weight disposed between said inlet and outlet to control the flow of .fluid therethrough, the lower endof said valve being formed on an obtuse taper whereby the weight of said valve will hold it seated to prevent fluid entry into said inlet until the liquid has reached a predetermined level in the well `below said inlet.

3. A ilow valve for eduction tubes including an elongated housing on the side of .said tube, a lateral entryadjacent lthe lower end of said valve, a downwardly inclined passage from -saidffliousing to said tube'a valveseat in said passage, a valve member' of predetermined weight shaped to i'lt within saidliousing and movable by fluid pressure to control said entry and said passage, the lower end thereof being more obtusely tapered than the upper end for the purpose stated.

4. A method of owing liquid from the tubing in wells comprising depressing, by means of gaseous fluid pressure, the level of liquid in the well outside said tubing, admitting gaseous iluid under pressure to said tubing at successively lower levels, and opening the entrance for said uid to said tubing only when the level of liquid in said well has fallen below the respective entrances for said fluid to said tubing. i

5. In the flowing of liquid from a well tubing by means of air or gas, the improvement consisting of depressing the level of liquid in the Well outside said tubing and opening up inlets for air to said tube at successively lower levels, only after the level of said liquid has passed below the respective inlets, and maintaining said liquid level below any of said open inlets.

JAMES W. TAYLOR.

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