US2358908A - Well swab - Google Patents

Description

Sept. 26, 1944. c. s. CRICKMER WELL SWAB v Filed March 3. 1941 l Chair/es S. C rick/War Patented Sept. 26, 1944 UNITED STATES PATENT OFFICE WELL SWAB Charles S. Crlckmer, Dallas, Tex. Application March 3, 1941, Serial No. 381,505

'IKJlalmS.

This invention relates to new and useful improvements in well swabs.

The usual type of well swab ordinarily includes a plurality of individual and separate parts, such as the mandrel, supporting thimble, swab cup and valve, which parts are assembled to provide a complete device. Any one or all of these parts, and particularly the swab cup are subject to wear and therefore,- require replacement. In order to replace any of the worn parts, the device must be completely dis-assembled which requires time and in many instances, considerable labor in the event the connections stick andbecome difficult to detach. Further, the device, with the exception of the resilient swab cup, is intended to be permanent and for this reason, the original cost, as well as the replacement expense, is relatively It is, therefore, one object of this invention to provide an improved well swab which is so simple and inexpensive in manufacture that the swab cup and mandrel may be discarded when the cup becomes worn, whereby replacement of worn parts is unnecessary.

An important object of the invention is to provide an improved well swab, wherein the swab cup is vulcanized, or otherwise permanently fastened to a tubular support, whereby the use of a separate retaining thimble for the swab cup is unnecessary; the construction being such that the tubular support may be coupled to a check valve, whereby the valve is not an integral part of the swab assembly, with the result that said swab includes a minimum number of parts which reduces the cost of manufacture to the point where the entire swab assembly may be economicalLv discarded when worn and replaced with a new assembly. A particular object of the invention is to provide an improved swab of the character described, wherein the bore of the swab cup is. permanently fastened to the tubular support, the upper portion of the cup being spaced from the support to form an annular sealing lip which is adapted to be expanded by fluid when the assembly is lifted upwardly through the well pipe.

Still another object of the invention is to provide a swab cup having its lower portion suitably reinforced either by an auxiliary reinforcing eleat the lower end of the cup, means for limiting the radial movement of the sealing lip at the upthe invention is to proof the character described, wherein the flexible swab cup may be permanently fastened to the mandrel by welding or otherwise securing the metallic reinforcing thimble which encloses the cup to the mandrel, whereby the cup is permanently mounted on the mandrel without the necessity of actually bonding the cup proper to the mandrel.

The 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, as

an example of the invention is shown, and

wherein:

Figure 1 is a view, partly in section and partly in elevation of a well swab, constructed in accordance with the invention, and illustrating the same within a well tubing,

Figure 2 is a horizontal, cross-sectional view, taken on the line 2-2 of Figure 1,

Figure 3 is a transverse, vertical sectional view of a modified form of the invention, and

Figure 4 is a vertical sectional view of still another form of the invention.

In the drawing, the numeral Ill designates a nipple or short length of pipe which forms a tubular mandrel or support. The mandrel has its ends externally screw-threaded and an elastic swab cup A is mounted on said mandrel, being preferably located nearer the lower end thereof.

The swab cup A comprises an annular body II which is preferably constructed of an oil resistant material, such as neoprene but may be made of rubber, rubber compound or other resilient material. The body II has an axial bore extending therethrough and said bore is of a diameter substantially equal to the external diameter of the mandrel. The mandrel l0 passes through the bore of the body and said body is preferably molded, or otherwise permanently bonded to the mandrel throughout the length Of said bore, whereby the swab cup is permanently affixed to the mandrel. The upper portion of the body is provided with an integral, annular sealing lip i3 which has its inner surface spaced from the outer surface of the mandrel. A plurality of vertically extending ribs M which are integral with the lip are spaced radially around said lip (Figure 2) and the inner longitudinal faces l5 of the ribs engage and are molded or bonded to the outer surface of the mandrel. Manifestly, the ribs divide the annular space between the sealing lip i3 and the mandrel into a plurality of recesses or pockets ii for the reception of fluid, which will urge or dis- 'the bore thereof; manifestly,

tort the sealing lip radially outwardly. Since the ribs H are bonded to the mandrel, it is obvious that said ribs function to reinforce and brace the sealing lip l3 to limit outward radial distortion to prevent said lip from being inverted by excessive fluid pressure. The upper surface of each rib is preferably inclined as shown at II to facilitate upward movement of the swab cup through couplings or other irregularities (not shown) in a string of pipe or tubing B, through which the swab is moved.

For further reinforcing the sealing lip II to limit outward radial distortion thereof, a plurality of reinforcing/annular elements I 8 are embedded within said lip. These elements may be cords, wires or the like and are molded within the lip at the time the body is formed. Mamfestly, the elements aid the vertical reinforcing ribs I in preventing the inverting of the lip by excessive fluid pressure which enters the recesses l8 to distort the lip outwardly. If desired, the reinforcing elements may be omitted.

and supporting the lower a metallic thimble or collar l9 surrounds the body and is molded or otherwise bonded thereto. The thimble encloses the entire lower portion of said body and has an opening 20 therein through which the mandrel extends. The lower portion of said thimble is rounded or curved to facilitate its passage through the tubing as it is lowered therethrough.

As has been pointed out, it is desirable to locate the swab cup at the lower portion of the mandrel, whereby the bottom of the thimble i9 is disposed adjacent the upper end of the screw threads on the lower end of said mandrel. Thus, when a coupling collar 2| is screwed onto the threads, the upper end of said collar may engage If desired, a plurality of swabs may be connected one above the other and as illustrated in Figure 1, a second swab assembly Al is disposed its mandrel threaded into the coupling collar 2|. Obviously, any required number of swabs for a predetermined load may be connected together.

The uppermost swab has the upper end of its mandrel l threaded into the lower end of a tubular valve cage 22 which has a plurality of fluid ports 23 in its side fined within the cage and is upon the upper end of the mandrel In to close when the ball is unseated an upward flow or by-pass of fluid through the mandrel is permitted. A tool joint 25 is threaded into the upper end of the valve cage and is adapted to be connected with rods 28, may be lowered and or conductor B. Of course, a cable socket may have connection with the tool Joint, in which event, the assembly may be moved through the tubing by means of a wire line or cable.

The operation of the swab wall. A .ball 24 is cona lifting of the other means.

by fluid within the tubing may freely by-pass the assembly as it is lowered through said fluid. A further by-pass of fluid is permitted upwardly through the tubular mandrel In, said fluid unradial ports 23 in the valve cage 22.

When the downstroke of the assembly is complete and an upward movement is imparted to the assembly to perform the swabbing action, the ball valve 24 is automatically seated by the weight of the fluid thereupon. The fluid also enters the spaces It within the annular sealing lip l3 and causes an outward radial distortion of said sealing lip, whereby its outs periphery engages the wall of the well tubing B. A continued upward movement of the assembly will result in fluid above the assembly and obviously, since the sealing lip I3 is in sealing contact with the wall of the tubing, said wall is swabbed.

is assured.

From the above, it will be seen that a very simple and efllcient l0 may be swab cup I I bonded tothe outer surface of the mandrel and on the upper end of This arrangement eliminates the expense of molding or bonding the cup proper to the mandrel.

brace or reinforcement for the base of the lip and operation of this form or the invention is substantially the same as has been described.

'The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

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

1. A well swab including, a tubular mandrel, an elastc annular swab cup surrounding the mandrel and having the wall of its bore permanently bonded to said mandrel, a flexible sealing lip at the upper portion of the cup adapted to be dis-' torted radially outwardly by fluid pressure and a plurality of vertical reinforcing ribs spaced radially within the sealing lip and integral'with said lip, said ribs having their inner faces engaging the exterior surface of the mandrel, said inner faces being permanently bonded to the mandrel throughout their entire lengths.

2. A well swab including, a tubular mandrel, an elastic annular swab cup surrounding the mandrel and having the wall of its bore permanently bonded to said mandrel, a plurality of reinforcing ribs integral with the sealing lip and extending between said lip and the mandrel, the entire inner vertical edges or surfaces of the ribs engaging said mandrel, and means for bonding said inner surfaces of the ribs to the mandrel throughout the entire length of each of said surfaces, whereby said ribs limit outward radial movement of the lip.

3. A well swab including, a tubular mandrel, an elastic annular swab cup having a sealing lip surrounding. the mandrel, a plurality of reinforcing ribs integral with the sealing lip and extending between said lip and the mandrel, said cupand ribs being bonded to the mandrel, an

annular metallic thimble surrounding the lower portion of the cup below the sealing lip'and molded thereto for bracing said lower portion of said cup, and means for permanently fasten- I ing the cup and thimble on the mandrel.

the vertical length of the lip and dividing, the

annular space between said lip and mandrel into a plurality of fluid receiving pockets, and means for bonding the inner surfaces of the ribs. which engage the mandrel to the mandrel, whereby said ribs limit outward radial movement of the lip, that portion of the cup. below the sealing lip being hardened, whereby such hardened portion acts to reinforce and brace the lower portion of said cup.

5. As a new article of manufacture, a swab including, a tubular support, an annular flexible swab element surrounding the support and having the lower portion of its bore engaging and permanently affixed to the support, a plurality of inwardly directed vertically extending ribs within the upper portion of the bore of the element, each rib having its inner vertical edge engaging the outer surface of the support, and means for bonding said inner edge of each rib to the sup- "port throughout the entire area of said edge.

6. A well swab including, a tubular support, an elastic annular swab cup surrounding the support and having the wall of its bore permanently bonded to said support, an annular flexible sea1-.

nular space between the lip and support, a plurality of reinforcing ribs integral with the sealing lip and extending between the lip and the support, the ribs extending through the vertical length of the lip and dividing the annular space between the lip and support into a plurality of fluid receiving pockets, and means for bonding the inner surfacesof the ribs which engage the support to said support, whereby said ribs limit outward radial movement of the lip.

7. A well swab as set forthin claim 6, together with means for reinforcing and bracing the lower portion of the cup below the sealing lip.

, CHARLES S. CRICIQVIER.

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