RU2379566C1 - Return valve - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention is provided for usage in oil wells with co sucker-rod pumps or with electric-centrifugal pumps, dispensing mainly liquids with high content of mechanical impurities. Return valve includes casing, seat, gate. The later is installed in restraint with tapered openings, transferring into tapered bores. Restraint is implemented with ability of increasing of open flow area between gate and restraint at axial movement of gate.

EFFECT: increasing of durability of return valve and increasing of processability of its manufacture.

6 cl, 5 dwg

Description

The invention relates to petroleum engineering and can be used in oil wells with sucker rod pumps or with electric centrifugal pumps, pumping mainly liquids with a high content of solids.

A known valve pump rod (according to the patent for utility model RU 42281) containing a locking element with a spherical or conical surface and a composite seat. The outer annular element of the saddle is made of plastic antifriction material, the inner annular element is made of wear-resistant solid, but brittle material. The holes of the outer and inner annular elements are formed by a conical tapering surface with a transition to a cylindrical surface. The result is an increase in the reliability of the valve due to the shock-free fit of the locking element on the inner annular element.

A known valve for pumping wells (according to the patent for utility model RU 50592), comprising a housing with an axial hole and a seat for seating the ball and a ball for closing the axial hole. When the ball lands in the saddle, fluid throttling occurs through the narrowed gap between the ball and the narrowing. The ball is braked, due to which the force of its impact on the landing saddle is sharply reduced. Known check valve (according to the patent for utility model RU 55018), consisting of a cylindrical body with an internal annular protrusion, a locking element mounted with the possibility of axial movement inside the body, a saddle fixed with a threaded sleeve, a limiter with holes for fluid flow.

A common disadvantage of the known valves is that when the valve is open, the shut-off element occupies mainly one position in the restrictor (in the cage), independent of the flow rate. In this case, the flow around the stream containing abrasive mechanical impurities of the shut-off element leads to the destruction of the walls of the body or cell.

Known non-return valve according to patent US 5593292, selected as a prototype, containing a stopper with holes for fluid flow, configured to increase the flow area with axial movement of the locking element. The holes are made in the form of sector cutouts. The body is made expanding bores. Its disadvantage is the low manufacturability of manufacturing holes and bores of complex shape, paired with each other on a complex surface. This requires milling. The design has insufficient rigidity (strength) and low wear resistance. When milling sector cuts, corners (stress nodes) are formed in which microcracks and other initiators of material destruction under load are formed. The jumpers between the sector cutouts, having a rectangular shape (top view), are also characterized by reduced rigidity (strength).

An object of the invention is to increase the service life of the check valve and increase the manufacturability of its manufacture.

The technical result is achieved in a non-return valve, comprising a housing, a seat, a shut-off element installed in the limiter with conical holes passing into conical bores for the flow of fluid. The limiter with conical holes and bores is made with the possibility of increasing the flow area between the locking element and the limiter during axial movement of the locking element. The angle of the solution of cone holes and bores is 1-20 degrees. The seat is secured with a nut and sleeve. The sleeve does not go beyond the dimensions of the housing, is equipped with a sealing ring and keyways. The limiter is made in the form of a cell, fixed with a snap ring. The locking element is made in the form of a ball.

The invention is illustrated figure 1-5: figure 1 - check valve assembly; figure 2 - sleeve;

figure 3 - limiter (cell); 4-5 - limiter (end view).

The check valve consists of a cylindrical body 1 with an inner annular protrusion 2. At the ends of the body 1 a thread 15 is made for mounting in a column. Inside the housing 1, a locking element 3 in the form of a ball, a saddle 4, a travel stop of the locking element 3 in the form of a cage 5 is installed. The saddle 4, ball 3, cage 5 are made of wear-resistant hard alloys, for example VK-15. The saddle 4 is installed on one side of the annular protrusion 2, and the cage 5 is fixed on the other side of the annular protrusion 2 using the retaining ring 6.

The locking element 3 is installed in the cell 5 with the possibility of axial movement inside the cell 5, equipped with holes 7 for the flow of fluid, passing into the bores 11, forming together with the jumpers 12 the inner walls of the cell 5, Fig.3. Jumpers 12 act as guides for the locking element 3.

Cell 5 (Figs. 3-5) is configured to increase the flow area between the locking element 3 and the cell 5 when the locking element 3 is axially moved. This is achieved by the fact that the openings 7 for the fluid duct and the bore 11 on the inner walls are conical. The angle of the solution of the cone holes 7 and the angle of the solution of the cone bores 11, which are performed by one tool during one technological operation, coincides and can be in the range of 1-20 degrees (figure 3 shows the angle α, which is half the angle of the solution). The angle of the solution depends on the diameter of the ball locking element 3 (on its mass).

The saddle 4 is fixed using a threaded nut 8 and a threaded sleeve 9, equipped with grooves 10, turnkey (figure 2). To protect the thread 13, the sleeve 9 is equipped with a sealing ring 14.

The check valve is manufactured and operates as follows. At the processing centers during one technological operation, a conical hole is made in the upper part of the cage 5, which passes into a conical bore. Holes and bores are performed with the same tool (drills and special reamers) from one installation, they are all made as coaxially with each other, with the same angle of the solution, the dimensional error is minimal. The simultaneous manufacture of conical holes and bores can improve the manufacturability of the operation and reduce the manufacturing time of parts.

Cone openings having a circle shape in cross section allow, with the same total bore, to achieve maximum stiffness (strength) of the limiter due to the fact that the circle area is maximum with the minimum length of the perimeter of the hole, as well as due to the biconcave shape of the jumpers on the limiter.

When used with pumps, the valve is installed in the tubing.

After turning on the pump, the working fluid enters through the threaded sleeve 8 to the locking element 3. Under the action of the liquid pressure, the locking element 3 rises from the seat 4 and moves inside the cage 5 along the guide bridges 12 in the direction of flow, forming a fluid flow inside the valve. The equilibrium position of the locking element 3 is achieved by aligning the gravity acting on the locking element and the force acting on it from the flow side. Next, the fluid passes through the holes 7 of the cell 5 and enters the valve outlet.

With increasing fluid flow, the force acting on the shut-off element from the flow side increases. The locking element 3 rises up along the guide jumpers 12. In this case, the passage section between the locking element and the inner walls of the cell 5 is increased and a new equilibrium position of the locking element 3 in the cell 5 is reached.

Thus, the uniformity of the wear of the walls of the cell 5 is achieved due to a smooth increase in the bore between the locking element 3 and the cell 5 during axial movements of the locking element between the extreme positions. In addition, the contact area between the locking element and the cage 5 is increased: in the zone of maximum wear, the size h of the jumper 12 is 2 times larger than in the zone of moderate wear, which leads to an increase in the service life of the maximum wearing part - cells (Figs. 3-5) .

When the pump stops, the shut-off element 3 under the pressure of the column of working fluid in the column is lowered into the seat 4, thereby preventing the reverse flow of the working fluid and holds the fluid in the string of tubing.

If it is necessary to replace the locking element 3 or the seat 4 in the valve, liquid is drained from the column above the non-return valve using a drain valve. To replace the seat 4 with the locking element 3, unscrew the threaded sleeve 9 with the nut 8. The sleeve 9 does not go beyond the dimensions of the housing 1, thereby reducing the flow resistance (increasing the efficiency of the entire installation) and increasing the wear resistance of the valve.

An o-ring 14, mounted in an annular groove in the sleeve 9, protects the thread 13 on the nut 8 from exposure to aggressive hydraulic fluid.

Claims (6)

1. The check valve, comprising a housing, a saddle, a locking element installed in the limiter with conical holes turning into conical bores, the limiter is made with the possibility of increasing the flow section between the locking element and the limiter during axial movement of the locking element. 2. The check valve according to claim 1, characterized in that the angle of the conical holes and bores is 1-20 °. 3. The check valve according to claim 1, characterized in that the seat is fixed with a nut and a sleeve. 4. The check valve according to claim 3, characterized in that the sleeve does not go beyond the dimensions of the body, is equipped with a sealing ring and keyways. 5. The check valve according to claim 1, characterized in that the limiter is made in the form of a cage fixed with a retaining ring. 6. The check valve according to claim 1, characterized in that the locking element is made in the form of a ball.

Images