CN113757387A - Piston assembly and sealing structure comprising same - Google Patents

Abstract

The invention discloses a piston assembly, which comprises a piston shaft, wherein a boosting piston and an elastic sealing ring are sequentially arranged on the piston shaft along the water flow direction, and one end of the sealing ring, which is far away from the boosting piston, is connected with a limiting piece in a matching way; the boosting piston and the sealing ring are sleeved outside the piston shaft and arranged in a sliding mode along the water flow direction. The invention also discloses a sealing structure. The piston assembly and the sealing structure form an annular gap for water or slurry to pass through by matching the boosting piston with the inner wall of the drill rod, and ensure that the flow passing through the annular gap is smaller than the flow conveyed by the water conveying device, thereby generating pressure for pushing the boosting piston to move towards the sealing ring, promoting the circumferential outer edge of the sealing ring to be tightly attached to the inner wall of the outer pipe, ensuring the sealing effect, realizing the delivery of the inner pipe assembly which is horizontal or inclined upwards, and because water flow is intensively acted on the boosting piston, pushing the limiting part to move through the sealing ring, and accelerating the delivery of the inner pipe assembly.

Description

Piston assembly and sealing structure comprising same

Technical Field

The invention relates to the technical field of drilling, in particular to a piston assembly and a sealing structure comprising the same.

Background

The wire-line core drill is an advanced drill capable of directly obtaining a core without lifting a drill, and is widely used due to the advantages of high production efficiency, low drilling cost and the like. Conventional wireline coring bits are typically adapted for down-hole use by relying on gravity to lower the inner tube assembly to a predetermined position within the outer tube assembly along the inner wall of the drill string.

When horizontal or inclined upward drilling is needed, in order to reduce abrasion, a sealing structure of a rope core-taking drilling tool disclosed in the Chinese patent invention with the publication number of CN206972184U is generally adopted, and the sealing structure of the rope core-taking drilling tool can not only maximize the utilization rate of water flow while realizing horizontal drilling; and the abrasion of parts is greatly reduced, and the service life is long.

However, in the sealing structure, after water flows into the groove along the length direction of the piston shaft, the water flow is mainly divided into two parts to act on the piston, one part acts on the circumferential outer wall on the inner side of the groove to promote the piston to expand outwards to be in sealing contact with the inner wall of the drill rod, so that the water flow utilization rate is increased, and the other part acts on the circumferential inner wall on the inner side of the groove to promote the central part of the piston to be in close contact with the piston shaft after being pressed, so that the delivery efficiency of the inner pipe assembly is reduced; in addition, the part of the piston expanding outwards is limited, so that the sealing performance between the piston and the drill rod is poor, part of water flow still passes through the gap between the piston and the drill rod, and the delivery efficiency of the inner pipe assembly is further reduced.

Accordingly, there is a need for improvements in piston assemblies and sealing structures or seal structures incorporating piston assemblies in prior art rope core drills.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a piston assembly with good sealing performance and high drilling efficiency and a sealing structure comprising the piston assembly.

In order to solve the technical problem, the invention provides a piston assembly which comprises a piston shaft, wherein a boosting piston and an elastic sealing ring are sequentially arranged on the piston shaft along the water flow direction, and one end of the sealing ring, which is far away from the boosting piston, is matched and connected with a limiting piece; the boosting piston and the sealing ring are sleeved outside the piston shaft and are arranged in a sliding mode along the water flow direction.

According to the piston assembly in the technical scheme, the whole device is arranged in the drill rod, so that a water flow channel exists among the boosting piston, the circumferential inner side wall of the drill rod and the circumferential outer edge of the piston shaft in the piston assembly, after the piston and the inner pipe assembly including the piston shaft are placed in the drill rod, the water or slurry delivered by the water delivery device can only pass through an annular gap (water flow channel) formed by the boosting piston and the inner wall of the drill rod, and because the allowable flow of the annular gap is far smaller than that delivered by the water delivery device, therefore, the water flow forms pressure between the water feeding device and the boosting piston, the pressure pushes the boosting piston to move towards the sealing ring along the length direction of the piston shaft, the other side of the sealing ring is under the action of the position limiting piece, thereby enabling the boosting piston to extrude the sealing ring, promoting the sealing ring to deform and expand outwards and tightly fit with the circumferential inner wall of the outer pipe, and ensuring the sealing property; and water flow is continuously introduced, the sealing ring is in close contact with the inner wall of the drill rod, and then the drilling tool is pushed, so that the delivery of the inner pipe assembly in the horizontal direction or in the inclined upward direction is realized. When the piston assembly is used, a little water flow passes through the water flow channel, most of the water flow acts on the boosting piston to push the sealing ring to deform, so that the sealing ring is in close contact with the inner wall of the drill rod, and sealing is kept, therefore, the utilization rate of the water flow is improved, water or slurry conveyed by the water conveying device can only pass through an annular gap (namely the water flow channel) between the boosting piston and the inner wall of the drill rod, and because the flow passing through the annular gap is far smaller than the flow conveyed by the water conveying device, pressure is formed between the water conveying device and the boosting piston, the pressure pushes the boosting piston to move towards the sealing ring along the axial direction of the piston shaft, the sealing ring is extruded, the sealing ring is radially expanded while being axially compressed, so that the circumferential outer edge of the sealing ring is tightly attached to the inner wall of the drill rod, and thorough sealing is realized; therefore, smooth movement of the boosting piston is guaranteed, acceleration of movement of the limiting part is facilitated, and delivery efficiency of the inner pipe assembly is improved.

Preferably, the sealing ring and the piston shaft are encircled to form an annular deformation cavity; or the sealing ring is provided with an annular deformation cavity, and the piston shaft is arranged on the inner side of the deformation cavity.

Through adopting above-mentioned technical scheme, reduced the material quantity of sealing washer, made the inside hollow structure that is of sealing washer, reduced the wall thickness to strengthen the elasticity of sealing washer, consequently receiving under the same pressure, the sealing washer has bigger deflection, and then guarantee to go up the inner tube assembly in the drilling tool level or slope and deliver the circumference inner wall that the back was pressed with the drilling rod inseparabler laminating, thereby guarantee the leakproofness.

Preferably, one side of the boosting piston, which is far away from the sealing ring, is provided with a radial partial pressure recess.

After the water or slurry is conveyed by the water conveying device, the water or slurry enters the radial partial pressure recess to generate component force in the radial direction, and if the boosting piston is an elastic piece, the outer side of the lip surface of the boosting piston is tightly attached to the inner wall of the drill rod under the action of the radial component force, so that the effect of closing a water channel is achieved; if the boosting piston is a rigid part, pressure is built by means of a gap between the outer wall of the boosting piston and the inner wall of the drill rod, axial displacement is generated, the sealing ring is axially compressed and radially expanded, the circumferential outer edge of the sealing ring is ensured to be tightly attached to the inner wall of the drill rod, and a sealing effect is achieved.

Preferably, the radial partial pressure recess is a closed ring groove, and the piston shaft is arranged on the inner side of the closed ring groove.

Through adopting above-mentioned technical scheme, guarantee to pour into rivers or mud back, under the condition that the boosting piston is the elastic component, increase radial deflection, and when the boosting piston was the rigid component, can promote the boosting piston and produce axial displacement, guarantee that the circumference outer fringe of sealing washer hugs closely the drilling rod inner wall, play sealed effect.

Preferably, the boosting piston is abutted against the sealing ring.

By adopting the technical scheme, the length of the whole piston assembly and the sealing structure comprising the piston assembly can be shortened, the size of the piston assembly is reduced, the installation is convenient, the water flushing amount required by the delivery of the inner pipe assembly is reduced, and the sealing performance of one end of the sealing ring opposite to the rotary joint is ensured; in addition, when the boosting piston is displaced, the boosting piston can act on the sealing ring immediately to push the sealing ring to deform and expand to be in close contact with the inner wall of the drill rod.

Preferably, the boosting piston and the piston shaft surround to form an annular positioning groove, and one end of the sealing ring, which is back to the adapter, is connected with the inner wall of the positioning groove in a sealing manner.

Through adopting above-mentioned technical scheme, utilize between boosting piston and the piston shaft to enclose the constant head tank that closes the formation, guarantee zonulae occludens between boosting piston, piston shaft and the sealing washer, prevent that rivers from revealing from the gap between the three.

Preferably, the material of the sealing ring is polyurethane.

By adopting the technical scheme, the sealing plug has excellent elasticity, elongation, compressive strength and flexibility and good chemical stability. On one hand, the piston assembly and the sealing structure comprising the piston assembly are conveniently assembled in the drill rod, so that the fault-tolerant rate of the pipe is higher, on the other hand, due to the excellent elasticity of polyurethane, after the same pressure is applied, the piston assembly has larger deformation, and can be quickly sealed with the inner wall of the drill rod, so that the delivery efficiency of the inner pipe assembly is improved; in addition, compared with common rubber, the polyurethane has stronger wear resistance, and the service life of the sealing element can be effectively prolonged.

In order to solve the technical problem, the invention further provides a sealing structure which comprises the piston assembly in any one of the technical schemes.

After the sealing structure of the technical scheme is arranged in the drill rod, water or slurry conveyed by the water conveying device can only pass through an annular gap (water flow channel) formed by the boosting piston and the inner wall of the drill rod, and because the allowable flow of the annular gap is far smaller than the flow conveyed by the water conveying device, water flow forms pressure between the water conveying device and the boosting piston, and the pressure pushes the boosting piston to move towards the sealing ring along the length direction of the piston shaft so as to extrude the sealing ring, so that the sealing ring expands and deforms outwards, the tight contact between the sealing ring and the inner wall of the drill rod is enhanced, and the sealing property is ensured; after water flow is continuously introduced, the water flow extrudes the sealing ring through the boosting piston, the sealing connection between the sealing ring and the inner wall of the drill rod is enhanced, and the drilling tool is further pushed by pushing the limiting part, so that the delivery of the inner pipe assembly in the horizontal direction or in the inclined direction is realized. When the sealing structure is used, the pressure difference generated by water flow at the boosting piston is utilized to push the boosting piston to extrude the elastic sealing ring, so that the close contact between the sealing ring and the inner wall of the drill rod is enhanced, the water flow is fully utilized, the boosting piston is prevented from being extruded to the inner side by the water flow, the quick movement of the boosting piston is facilitated, and the delivery efficiency of the inner pipe assembly is improved.

Preferably, the limiting part is an adapter, and the adapter is connected with the piston shaft.

Through adopting above-mentioned technical scheme, make things convenient for this seal structure's installation.

Preferably, the piston shaft is in threaded connection with the adapter.

By adopting the technical scheme, the quick fixed connection between the rotary joints of the piston shaft is realized by utilizing the threaded connection.

In summary, the piston assembly and the sealing structure comprising the piston assembly of the present invention form an annular gap through which water or slurry passes by the aid of the boost piston in cooperation with the inner wall of the drill rod, and ensure that the flow rate of the annular gap is smaller than the flow rate delivered by the water delivery device, so as to generate a pressure for pushing the boost piston to move toward the sealing ring, so as to urge the circumferential outer edge of the sealing ring to be tightly attached to the inner wall of the outer tube, thereby ensuring the sealing effect, so as to realize the delivery of the inner tube assembly which is horizontal or inclined upwards, and because the water flow is concentrated on the boost piston, the limit piece is pushed to move by the sealing ring, thereby accelerating the delivery of the inner tube assembly.

Drawings

FIG. 1 is a schematic structural view of a piston assembly of the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a sectional view taken along line A-A of FIG. 1;

FIG. 4 is a cross-sectional view of the present invention in use;

FIG. 5 is a schematic structural view of a seal structure of embodiment 1 of the present invention;

FIG. 6 is an exploded schematic view of FIG. 5;

FIG. 7 is a top view of FIG. 5;

FIG. 8 is a cross-sectional view taken along line B-B of FIG. 7;

FIG. 9 is a schematic view of the connection of the piston shaft to the booster piston;

FIG. 10 is a schematic structural view of a seal ring according to embodiment 2 of the present invention;

in the figure: 1. the hydraulic drill rod comprises a piston shaft, 1-1 parts of elastic clamping step openings, 2 parts of elastic clamping frames, 3 parts of adapters, 3-1 parts of piston step openings, 4 parts of boosting pistons, 4-1 parts of radial partial pressure recesses, 5 parts of sealing rings, 6 parts of deformation chambers, 7 parts of positioning grooves, 8 parts of steel wire meshes and 9 parts of drill rods.

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1 to 3, the piston assembly of the present invention includes a piston shaft 1, one end of the piston shaft 1 is provided with a limiting member, the limiting member is an adapter 3, an annular boosting piston 4 and an elastic sealing ring 5 are sleeved outside the piston shaft 1 in a sealing manner, the boosting piston 4 and the sealing ring 5 are distributed along the length direction of the piston shaft 1, two ends of the sealing ring 5 are respectively connected with the boosting piston 4 and the adapter 3, the boosting piston 4 is made of a rigid material, preferably No. 45 steel, and the sealing ring 5 is made of an elastic material, preferably polyurethane; the cylindrical surface attached to the sealing ring 5 is a sealing surface, the boosting piston 4 is arranged on the inner side of the sealing surface, and the sealing surface and the piston shaft 1 are used for being combined with the inner wall of the drill rod to form an annular water flow channel; along the length direction of the piston shaft 1, the cross-sectional area of the water flow channel is smaller than that of the boosting piston 4; the circumferential outer edge of the booster piston 4 is in clearance fit with the sealing surface.

After the piston assembly is installed in a drill rod 9 (shown in fig. 4), the circumferential inner wall of the drill rod 9 is attached to the circumferential outer edge of the sealing ring 5, namely the sealing surface is an annular surface where the circumferential inner wall of the drill rod 9 is located, a gap exists between the circumferential outer edge of the boosting piston 4 and the circumferential inner wall of the drill rod correspondingly, and due to the existence of the gap, the boosting piston 4 and the drill rod are prevented from generating extra friction resistance to cause mutual abrasion.

The inner pipe assembly including the piston and the piston shaft is placed into a drill rod and then connected with a water supply device, when a drilling tool is delivered to the inner pipe assembly horizontally or obliquely, water is injected into the drill rod by the water supply device, at the moment, the distribution direction of the boosting piston 4 and the sealing ring 5 on the piston shaft 1 is coincident with the water flow direction, water or slurry conveyed only can pass through an annular gap (water flow channel) formed by the boosting piston 4 and the inner wall of the drill rod 9 due to a gap between the boosting piston 4 and the drill rod, and because the allowable flow of the annular gap is far smaller than the flow conveyed by the water supply device, the water flow forms pressure between the water supply device and the boosting piston 4, the pressure pushes the boosting piston 4 to move towards the sealing ring 5 along the length direction of the piston shaft 1, so as to extrude the sealing ring 5, so that the sealing ring 5 deforms and expands, and the sealing ring 5 is completely attached to the circumferential inner wall of the drill rod, the sealing performance between the sealing ring 5 and the drill rod is ensured, and then the drilling tool is pushed, so that the horizontal or inclined upward delivery of the inner pipe assembly is realized.

Because in this piston assembly, the circumference outer fringe of boosting piston 4 and sealed face (being the circumference inner wall of drilling rod) clearance fit for only there is a little rivers through the rivers passageway, and boosting piston 5 bears rivers along the major part pressure of piston shaft 1 length direction simultaneously, and then promotes and extrudees sealing washer 5 with higher speed, makes sealing washer 5 outwards warp the inflation fast, strengthens the leakproofness between its and the drilling rod, therefore this piston assembly leakproofness is good, helps improving inner tube assembly and delivers efficiency.

In the piston assembly, the boosting piston 4 is preferably made of No. 45 steel, has rigidity, is not easy to deform and ensures stable compression; the sealing ring 5 is preferably made of polyurethane and has ultrahigh elasticity, so that the piston assembly and the sealing structure comprising the piston assembly have higher fault tolerance rate on the pipe, and the sealing ring 5 has larger deformation under the same pressure, can be rapidly sealed with the drill rod, further accelerates the propulsion of the drill rod and improves the delivery efficiency of the inner pipe assembly.

As shown in fig. 3, the seal ring 5 and the piston shaft 1 surround each other to form an annular deformation chamber 6. By adopting the structure mode, the wall thickness of the sealing ring 5 is reduced, the elasticity of the sealing ring 5 is increased, so that the sealing ring 5 has larger deformation under the condition of the same extrusion acting force, and the sealing connection between the sealing ring 5 and the drill rod is further ensured; and because the wall thickness of the seal ring 5 is reduced, the production material consumption of the seal ring 5 is reduced, and the manufacturing cost is reduced. It should be noted that the seal ring 5 may be provided in a hollow structure, for example, in a case where the seal ring 5 has an annular deformation chamber 6 and the piston shaft 1 is located inside the deformation chamber 6, the above-described technical effects can be achieved similarly.

As shown in fig. 3, a radial partial pressure recess 4-1 is formed in a side of the boost piston 4 facing away from the seal ring 5, the radial partial pressure recess 4-1 is a closed-loop groove, and the piston shaft 1 is disposed inside the closed-loop groove. After the water or slurry is conveyed by the water conveying device, the water or slurry enters the radial partial pressure recess 4-1, so that component force is generated in the radial direction, and because the boosting piston 4 is a rigid part, pressure is established by means of a gap between the outer wall of the boosting piston 4 and the inner wall of the drill rod 9, axial displacement is generated, the sealing ring 5 is radially expanded while being axially compressed, and the circumferential outer edge of the sealing ring 5 is ensured to be tightly attached to the inner wall of the drill rod, so that a sealing effect is achieved.

As shown in fig. 1, the boosting piston 4 abuts against the sealing ring 5, which is beneficial to reducing the length of the piston shaft 1 and further reducing the overall size of the piston assembly, when the inner pipe assembly is delivered, the usage amount of water flow is reduced, when the boosting piston 4 is subjected to water flow pressure to generate displacement, the sealing ring 5 can be extruded, and the sealing connection between the sealing ring 5 and the outer pipe is enhanced after the sealing ring 5 is deformed.

As shown in fig. 1-3, the boosting piston 4 and the piston shaft 1 surround to form an annular positioning groove 7, and one end of the sealing ring 5, which is opposite to the rotary joint 3, is connected with the inner wall of the positioning groove 7 in a sealing manner. After adopting this design, when piston assembly's installation, with wherein one end butt in the tank bottom of constant head tank 7 of sealing washer 5, at this moment, two circumference inner walls of constant head tank 7 butt respectively in the circumference outer wall and the circumference inner wall of sealing washer 5 tip, sealing connection between sealing washer 5 and the constant head tank 7 has so been realized, when preventing that the inner tube assembly from delivering, rivers are revealed between constant head tank 7 or sealing washer 5 and piston shaft 1, guaranteed piston shaft 1, boosting piston 4 and the sealing connection between the sealing washer 5 three.

As shown in fig. 1, a piston shaft 1 is connected with an adapter 3 through threads, and a piston stepped opening 3-1 is formed in one side, adjacent to the piston shaft 1, of the adapter 3.

By adopting the structure, the end part of the piston shaft 1 is quickly and fixedly connected with the adapter 3 in a threaded connection mode, and the piston shaft 1 and the adapter 3 are pre-compacted by utilizing the piston step opening 3-1, so that the machining deviation can be prevented, the assembly precision of the piston assembly and the sealing structure comprising the piston assembly is improved, and the normal use of the piston assembly is ensured.

The invention also discloses a sealing structure of two embodiments, which comprises the following steps:

example 1

As shown in fig. 5 to 9, the sealing structure of embodiment 1 includes the piston assembly in the above technical solution, an elastic clip frame 2 is disposed at one end of the piston shaft 1 opposite to the counter-rotating joint 3, the elastic clip frame 2 is in threaded connection with the piston shaft 1, and an elastic clip stepped port 1-1 is disposed at one side of the piston shaft 1 adjacent to the elastic clip frame 2.

By adopting the structure, the piston shaft 1 is quickly connected with the elastic clamping frame 2 (the elastic clamping frame 2 is used for connecting the elastic calipers) in a threaded connection mode, and the piston shaft 1 and the elastic clamping frame 2 are pre-compacted by utilizing the elastic clamping step port 1-1, so that the machining deviation can be prevented, the assembly precision of the sealing structure is improved, and the normal use of the sealing structure is ensured.

After the whole sealing structure is arranged in a drill rod, water is supplied by a water supply device, part of water flow impacts on the boosting piston 4, and part of water flow passes through a water flow channel, wherein the flow passing through the water flow channel is smaller than the flow conveyed by the water supply device, so that pressure difference is generated between the boosting piston 4 and the water supply device to push the boosting piston 4 to move, the sealing ring 5 is extruded, the sealing ring 5 is expanded and deformed outwards, the sealing performance between the circumferential outer edge of the sealing ring 5 and the inner wall of the drill rod is enhanced, the water flow is intensively acted on the boosting piston 4, and the horizontal or inclined upward delivery of the inner pipe assembly is realized.

Example 2

As shown in fig. 10, the piston assembly and the sealing structure including the piston assembly in embodiment 2 are different from those in embodiment 1 in that annular and rigid fixing members are respectively disposed inside both ends of the sealing ring 5, an axial line of the fixing member coincides with an axial line of the sealing ring 5, and the fixing member is a steel wire mesh 8.

In this embodiment, inside behind the setting wire net 8 in the both ends of sealing washer 5, can increase the rigidity at 5 both ends of sealing washer, receive the extrusion back when sealing washer 5, the deflection at its both ends is little, and it is relative, the protruding position deflection in center of sealing washer 5 is big, make the protruding deformation in center of sealing washer 5 and the inside in close contact with of drilling rod, consequently under receiving equal pressure, this sealing washer 5 has more excellent leakproofness, make rivers concentrated action on boosting piston 4, rethread sealing washer 5 acts on adapter 3, thereby accelerate inner tube assembly delivery efficiency. The shaping member may be another rigid ring coaxial with the seal ring 5, and the above technical effects can be achieved similarly.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. Piston assembly comprising a piston shaft (1), characterized in that:

a boosting piston (4) and an elastic sealing ring (5) are sequentially arranged on the piston shaft (1) along the water flow direction, and one end, far away from the boosting piston (4), of the sealing ring (5) is connected with a limiting piece in a matched mode; the boosting piston (4) and the sealing ring (5) are sleeved outside the piston shaft (1) and are arranged in a sliding mode along the water flow direction.

2. The piston assembly of claim 1, wherein: the sealing ring (5) and the piston shaft (1) are encircled to form an annular deformation cavity (6); or the sealing ring (5) is provided with an annular deformation cavity (6), and the piston shaft (1) is arranged on the inner side of the deformation cavity (6).

3. The piston assembly of claim 1, wherein: one side of the boosting piston (4) far away from the sealing ring (5) is provided with a radial partial pressure recess (4-1).

4. The piston assembly of claim 3, wherein: the radial partial pressure recess (4-1) is a closed ring groove, and the piston shaft (1) is arranged on the inner side of the closed ring groove.

5. The piston assembly of claim 1, wherein: the boosting piston (4) is abutted against the sealing ring (5).

6. The piston assembly of claim 5, wherein: boosting piston (4) with piston shaft (1) encloses and surrounds annular constant head tank (7), sealing washer (5) are dorsad the one end of adapter (3) with the inner wall sealing connection of constant head tank (7).

7. The piston assembly of claim 1, wherein: the sealing ring (5) is made of polyurethane.

8. A sealing structure, characterized in that: comprising a piston assembly according to any one of claims 1 to 7.

9. The seal structure of claim 8, wherein: the locating part is adapter (3), adapter (3) with piston shaft (1) is connected.

10. The seal structure of claim 9, wherein: the piston shaft (1) is in threaded connection with the adapter (3).

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