RU2224086C1 - Mouth device for well pump rod - Google Patents

Abstract

FIELD: operating wells mouth equipment engineering. SUBSTANCE: device has cylindrical body of packing chamber and rod centering assembly. Centering assembly is made in form of two inserts. Each insert is capable of self-placing along the rod and being pressed to the rod by means of pressing member. Packing chamber is delimited on both sides by a pair of pressing rings. Outer rings of pair are spaced from packing chamber wall. As a compactor for packing chamber grease lubricant with filler is used. Device also has supply valve and technical means for countering pressure from compactor relative to environment being compacted. EFFECT: lessened load on rod centering assembly in case of its radial or angular misalignment, assured rod impermeability during its movement and centering rod wearing independently of wasting of compactor up to its full consumption, possible compactor replenishment without packing chamber depressurization. 2 dwg

Description

The invention relates to the mining industry, in particular to the wellhead equipment of operating oil wells, and is used to seal the rod of a rocking pump of a deep pump under misalignment, both in radial and angular coordinates.

A device for sealing the rod by A. with. No. 2103574, cl. E 21 B 33/03, including a stuffing box, the housing of which has mobility in the radial direction, which reduces the effect of misalignment of the rod on the wear of the device.

The disadvantage of this device is that the elements that ensure the tightness of the moving housing of the stuffing box are in contact with the medium being sealed and, as a result, are subject to intense corrosion, which leads to a loss of tightness.

In addition, the device does not eliminate the effect of misalignment in the angular coordinate and is difficult to manufacture.

Known wellhead device for sealing the rod of a submersible pump by as No. 1696672, cl. E 21 B 33/03, which includes a housing with a stuffing box and a centralizer assembly. The centralizer assembly has a slider with a pressure bolt. The slider perceives the radial force of the rod, resulting from its misalignment. As the slider wears out, it is periodically pressed with a pressure bolt, returning the rod to its original position.

The disadvantage of the design is that when the slider is worn, one-sided wear of the packing elements of the stuffing box occurs at the same time and a gap appears on the opposite side of the stem, that is, a leak in the stem occurs.

A common drawback of both devices is that frequent maintenance of the device is necessary to maintain the tightness of the stem seal. Maintenance consists in pulling up the pressure elements of the stuffing box to compensate for the removal of the sealing material. Even with a small outflow, the back pressure of the sealing material with respect to the medium being sealed disappears, which practically means a violation of the stem tightness.

Another disadvantage of the known devices is the need for the design of a backup stuffing box, which generally reduces the reliability of the device and complicates the design. The decrease in reliability of the entire device is due to the direct contact of the medium being sealed with the sealing elements of the backup stuffing box, which leads to intense corrosion of the sealing elements and loss of tightness of the entire system. The backup stuffing box is brought into working position only for the time of replacement of the worn packing material of the main stuffing box.

The objective of the invention is:

- reducing the effect of misalignment of the rod on the wear of the elements of the centering unit, both in radial and angular coordinates;

- ensuring the tightness of the rod at almost any degree of wear of the elements of the centering rod;

- eliminating the need for maintenance of the device to compensate for the removal of the sealing material up to its full consumption;

- simplifying the design and improving the reliability of the device by eliminating the need for a backup stuffing box in the design of the device.

When achieving the objective of the invention, the following technical result is achieved:

- reducing the load on the centering node of the rod when it is misaligned, both in radial and in angular coordinate;

- maintaining the tightness of the rod during its movement after wear of the support element of the centering unit;

- maintaining the tightness of the rod, regardless of the removal of the sealing material up to its full consumption;

- providing the possibility of replenishment of the stuffing box with sealing material without its depressurization, that is, without the need for a backup stuffing box.

The technical result is achieved by the fact that in the known device for sealing the rod of a submersible pump, comprising a cylindrical housing of the stuffing box and a centering unit of the rod, the centering unit is made in the form of two liners, each of which has the ability to mount on the rod and be pressed against the rod by a pressing element, and the stuffing box is limited on both sides by a pair of pressure rings, while the outer rings of the pair have a gap with the wall of the stuffing box, and as a packing material the stuffing box A grease with filler was used, and the device is equipped with a discharge valve and technical means to provide back pressure of the sealing material with respect to the medium being sealed.

The use of two inserts in the centering unit, each of which has the ability to self-mount on the rod and be pressed by the pressing element to the rod, means their mutual centering, both in radial and angular coordinates or near this position. As a result, the liners that perform the functions of radial bearings either do not experience a radial load at all, or the load is significantly reduced and thereby their wear is reduced.

The restriction of the stuffing box on both sides of the pair of pressure rings, in each of which the outer ring has a gap with the wall of the stuffing box, and the use of grease with filler as a sealing material provides increased ductility and, as a result, maintaining the stem tightness when moving after wear of the support element centering unit.

The availability of technical means to ensure backpressure of the sealing material in relation to the medium being sealed, together with the increased ductility of the packing material of the stuffing box and its sufficiently large volume, allows for a long time to ensure stem sealing, regardless of the removal of the packing material, up to its full consumption.

The discharge valve in combination with a sealing material with increased ductility allows it to be recharged as the sealing material is removed without depressurization of the stem and, therefore, without the need for a backup stuffing box.

During the search, no analogues were found in the prior art that would contain significant distinctive features of the claimed technical solution from the prototype. The inclusion in the design of the device of the declared distinctive features in conjunction with the general ones allows you to get a new technical result that is not inherent in the known analogues, as well as the known signs separately.

Thus, the claimed invention does not follow for the specialist explicitly from the prior art as determined by the applicant, since the effect of the transformations provided for by the essential features of the claimed invention on the achievement of the technical result has not been identified.

Figure 1 shows a General view of the device.

Figure 2 shows the profile of the sealing surfaces of the pressure rings.

The device consists of a housing 1, in the upper part of which there is a centering unit, consisting of a cup 2 and a pair of support liners 3 made of antifriction material. The liners 3 are pressed against the stem 4 by pressure screws 5. The glass is stopped from turning by a screw 6. The stuffing box of the device is bounded above and below by a pair of pressure rings - external 7 and internal 8. The external ring 7 has a gap with the housing wall 1. The nature of the sealing surfaces of the pressure rings 7 and 8 is shown in FIG. 2. The cavity of the stuffing box is filled with a sealing material 9, which is a mixture of grease (base) with a filler in which, for example, a fibrous component is present.

To fill the chamber with sealing material, a pressure valve assembly 10 is provided. From below, the sealing material is pressed by a spring 11 through the pressure rings 7 and 8. The spring 11 is designed to provide back pressure of the sealing material 9 with respect to the medium being sealed.

The device operates as follows. When mounting the device to the well, the support liners 3 are installed along the rod 4. If the misalignment of the rod 4 is not completely selected, then the glass 2 is turned into a position in which one of the liners 3 can perceive the radial load of the rod 4. The position of the glass 2 is fixed with a screw 6 . Through the site of the discharge valve 10 using a manual lubricator, the stuffing box is filled with sealing material 9. The spring 11 is compressed and the pressure in the stuffing box is created in excess of the pressure of the medium being sealed value corresponding to the force of the spring 11.

Due to the excess pressure of the sealing material 9, the rod 4 is reliably sealed. The end surfaces of the pressure rings 7 and 8 are also constantly pressed against each other. The lower pair of rings 7 and 8 is pressed against each other with less force than the upper ones, since part of the force from the pressure of the sealing material 9 on the ring 8 is perceived by the pressure of the medium being sealed. Nevertheless, the spring 11 in any case provides contact pressure when the end surfaces of the rings 7 and 8 interact, more than the pressure of the sealing material 9 in the stuffing box, which ensures tightness along the end surfaces of the pressure rings 7 and 8.

In the process of injection of the sealing material 9, as well as with increasing pressure of the medium being sealed, temporary extrusion of the base of the sealing material occurs. Near the extrusion sites, self-pressing of the filler and, first of all, its fibrous component occurs (see FIG. 2). Over time, the filler becomes impervious to the base of the sealing material. Self-pressing of the fibrous fractions at the places where gaps occur, contributes to the preservation of the inner surface of the ring 7 up to the complete cessation of wear.

The inner cylindrical surface of the sealing rings 8 can act as a centralizer to a certain degree of wear, temporarily unloading the liners 3 from work.

The presence in the stuffing box of a sufficiently large amount of sealing material 9, the provision of excess pressure in the chamber, the durability of the sealing surfaces of the ring 7 and the ability of the sealing material 9 to self-press at the points of occurrence of gaps provide a sharp increase in the overhaul period and the period of time between regular maintenance.

Claims (1)

A wellhead device for sealing the rod of a submersible pump, comprising a cylindrical housing of the stuffing box and a centering assembly of the stem, characterized in that the centering assembly is made in the form of two inserts, each of which has the ability to mount on the stem and be pressed against the stem by a pressure element, and the stuffing box is limited there are a pair of pressure rings on both sides, while the outer rings of the pair have a gap with the wall of the stuffing box, and a consist ntnaya grease filled, the apparatus is provided with a discharge valve and means for providing the counter-sealing material in relation to the sealing medium.

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