US2224916A

US2224916A - Well swab

Info

Publication number: US2224916A
Application number: US169101A
Authority: US
Inventors: George W Mcfarlane
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-10-15
Filing date: 1937-10-15
Publication date: 1940-12-17
Anticipated expiration: 1957-12-17

Description

Dec. 17, 1940. G. W.-M 1FARLANE WELL SWAB Filed Oct. 15, 1937 Geo. W. M$Farlane Patented Dec. 17, 1940 UNITED STATES PATENT OFFICE 2,224,9165 WE S A George WQMcFarlane, Houston, Tex. Application October 15,1937, Serial No. 169,101 2 Claims. (c1; 10. 9225) This invention relates to new and useful improvements in well swabs. I

One object of the invention is to provide an improved well swab-of what is known as the rapid or fast falling type. a

'A particular. object of the invention is to provide an improved well swab having a support provided with full-flowing channels or passages for freely by-passing the liquids and fluids through the swab body or sleeve member, whereby the swab may be rapidly lowered into the liquid at the bottom of the well.

A further object of the invention isto provide ing movement vertically of the channeled portion of the mandrel to fully open the channel or groove upon the downstroke and to ailorda free by-passing of the fluids and liquids.

Another object of the invention is to provide a swab sleeve including a metallic liner having a smooth cylindrical bore for freely sliding on a mandrel, as well as having an annular seating face at its lower end, together with an elasticsleeve removably mounted on the liner and arranged to be expanded by thefluid pressureiw'ithin the liner. to cause said sleeve to seal against the inner wall of the tubing or casing in-Which the swab is being run. l

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, in

which an example of the invention is shown, and

wherein: I

Figure l is a view, partly in elevation and partly in section, showing a swab constructed in accordance with the invention, the swab sleeve being unseated.

the mandrel to communicate with an "inclined elongate mandrel, preferably cruciform in crosssection 'althoughnot necessarily, whereby longitudinal channels or. passages II are formed on the. outer surface of said mandrel by longitudinally extending ribs Ill. The upper end of the Z5;

mandrel is formed with an enlarged cylindrical head I2 having an axially upwardly extending pin I3, which is provided with screwthreads l3 and is. adapted to be screwed into asuitable socket orother suspending means. 7

The channels H extend the major portion of the length of the mandrel, terminating at their upper ends in outwardly curved outlets H in the head. An annular swab sleeve 15 is; mounted t0 s1ide vertically on the mandrel. The sleeve 15 is composed of a metallic cylindrical liner 16 which has a plurality of radial ports .l'l formed in its midsection. The upward movement of the sleeve is limited by stop shoulders ill formed by the head overhanging the mandrel.

The liner I6 is provided with an enlarged-lower end having an upwardly extending .flange' I8 which forms an annular recess t6 between the flange and the liner, while theupper endof said.

liner is'screw-threaded to receive a lock nut 19. ,25 An annular, elastic packer 20, having its ends re duced to form skirts 20', is mounted upon theliner. The lower skirt 20 of the packer engages within the recess l6 formed by the flange l8. For confining the upper skirt of thepacker, an annular follower 2|,having a depending flange 22' is mounted upon the liner above said packer. The follower 2| is held in position upon the liner by the lock nut l9, and it is apparent that the packer is confined upon sai d liner' between the $5,

flanges l8 and 22. v

I The lower end of the mandrel ill is provided with a depending screw-threaded pin 23 having anaxial duct 24. The duct extends upwardly into 40 duct 25, formed in. said mandrel and" having a port 26 opening into one of thechannel's H. A valve case 27; having an internally screwthreaded socket 28, is threaded onto the pin 23, whereby said valve case is secured to the mandrel. The case 21 has a screw-threaded socket 29 and a counter bore 38 which has its lower portion screw-threaded to receive a plug 3] v,

The upper portion of the bor'eforms a valve cage 32 which is provided with a radial outlet port 33. A ball or check valve 34'is held in -seating position by a helical spring 35 at'the upper end of said cage against a valve seat '36. The plug 3| compresses the spring 35 and holdsit in position within the cage 32, whereby the-ball upon the upstroke.

the seat38 of the valve case.

valve 34 is held in tight engagement with the seat 36. It is noted that the plug regulates the compression of the spring which in turn determines the amount of fluid pressure necessary to unseat the valve. An axial inlet port 31 provided in the upper portion of the valve case 2! establishes communication between the socket 28 and Valve cage 32, between the duct 24 and the cage 32 with its outlet port 33. larger in diameter than the mandrel and has its upper end beveled to form a valve seat 38 to receive the beveled valve face 39 formed in the lower end of the liner N5 of the swab sleeve l5.

In operation, the device is connected in the usual manner to a cable or other suspending means and is lowered into a well tubing or casing,

either for cleaning purposes or for lifting fluid I As the device is being lowered, the swab sleeve 15 will slide upwardly on the from the well.

ribs in of the mandrel until the lock nut'IS strikes the shoulders M which prevents further upward movement of said swab. It will be obvious that when the sleeve strikes the shoulders 14, the outlets II will remain open, thus permitting the fluids to'freely flow through the channels II and by-pass the swab sleeve l5, whereby the swab will readily descend into the well liquids; consequently the device may be rapidly lowered to the desired depth in the liquid standing in the well. The velocity of the downward movement of the swab is much greater than that of the conventional swab due to the by-passing of the liquids and fluids, as has been hereinbefore described.

When the swab reaches the bottom of its run, the swab sleeve will fall or slide downwardly on the mandrel until the valve face 39 of the liner or tubing whereby the liquids and fluids will not by-pass around the exterior of the swab packer The swab assembly may then be raised to the surface and the liquids and fluids thereabove, will be carried upwardly with it, since the weight of the liquids and fluids will hold the face 39 of the liner in tight engagement with This operation may be repeated whenever, and as many times as seems desirable to the operator.

The amount of liquids raised by the swab is predetermined by the compression of the helical spring 32 which is regulated by setting the plug 3!; This is a safety device designed to prevent overloading of the swab. When the spring is under the desired compression the excess amount of liquids above the swab will be bled off. This bleeding action is accomplished by a portion of the liquids flowing down through the inclined duct 25 which communicates with one of the channels ll, then into the duct 25 and the inlet port 31, where it will contact the ball valve 34. If there is an excessive amount of liquids above the swab, the weight of said liquids will force the valve from its seat 36, the excess liquids passing thereby and escaping through the out let port 33. When sufficient liquids have been bled off by this means, the weight will be reduced, thereby permitting the valve 34 to reseat itself and prevent the further escape of said liquids.

The case is It is desirable to have the sleeve liner it slide freely up and down the mandrel l0, but no spacing or great clearance between the complementary faces of the ribs I and the bore of said liner is required. Therefore there is substantially no side play or lateral movement of the valve sleeve. The liquid being lifted will lubricate the ribs, and so as long as the sleeve slides freely, the necessities of the swab will be met. It is highly desirable for the face 33 to evenly! engage the seat 38 and undue lateral movement of the sleeve would interfere with proper seatmg.

The ribs l0 formed by the channels H provide elongate smooth guides for the liner [6 of the swab sleeve and preclude cutting or scoring of the parts, such as is likely to occur where 'arcuate keys are used, particularly where such ,keysprotrude from the base of the liner and ride on a smooth mandrel. The channels I I are long enough, preferablybeing more than twice the length of the swab sleeve l5, to promote free flowing of the by-passingliquids and the swab sle'e'vehas "sufficient travel to dislodge or escape any obstruction which may lodge in said ch'an nels or at the ends of the sleeve. The outlets H are important as they provide a free escape for the liquids andfiuids when the swab is descending rapidly. l

In Figure 5, a pair of swab assemblies shown -mounted in tandem or one above the other, whereby the load of the fluid column is carried by both swab sleeves rather than by one of said sleeves. The amount of fluids raised by each swab is, of coursdpredetermined by the com pression of each helical spring '32. 'When the weight of the fluid column above the upper swab is excessive, the excess amount is bled off as hereinbefore set forth. Theexcess fluids and liquids from the upper swab will be caught and carried upwardly. by the lower swab. However, it is pointed out that if the weight of these fluids and liquids exceed the compression of the lower helical spring that the excess will be bled off in a similar manner. Thus, if the:- weight of the fluid column exceeds the compression of both springs, it is obvious that the excess amount will be bled off by the unloading valves. By this arrangement the load carried by each sleeve is limited to a predetermined amount by its unloading valve, whereby the load of the fluid column is evenly distributed so as to prevent overloading of the swabs and, consequently excessive wear of the packers 20.

What I claim and desire to secure by Letters Patent is:

1. The combination with a pair of swabs mounted in tandem including, a pair of elongate mandrels having a channel, a swab sleeve slidable vertically on each mandrel, an enlarged head at the upper end of each mandrel overhanging the channel and forming a' stop for the sleeve, valve means for closing the lower end of said mandrel and having a seat-at its lower end,

and a valve case screwed onto. said pin and having a stop for receiving the seat of the swab element for closing ofi said channels to a downiward flow and leaving said passage exposed for draining.

GEORGE W. MCFARLANE.