阅读说明：本技术 潜油直驱专用螺杆泵 (Special submersible direct-drive screw pump ) 是由 勾国伟 李德印 岳修业 宋宇飞 熊健伟 郭胜男 姜小龙 于 2020-12-04 设计创作，主要内容包括：本发明实施例涉及井下油液举升技术领域,具体涉及一种潜油直驱专用螺杆泵,其包括动力单元、定子和转子,其中：定子包括筒体和模压在筒体内壁、由高弹性合成橡胶制成的伸缩体,伸缩体内设置有挤压腔,筒体和伸缩体上对应设置有第一进油孔和第二进油孔；在动力单元的驱动下转子可转动地安装于挤压腔内,转子的外部设有螺旋结构的作用部,作用部与挤压腔的初始过盈量为-1.5mm-0.5mm；转子的转速为50rpm-500rpm。本发明实施例的有益效果为：即减小初始过盈值或提高间隙量,大幅降低启动扭矩,解决潜油直驱螺杆泵启不动的问题,同时提高转速弥补漏失量大容积效率低的现象；同时降低了伸缩体的变形量,避免其变形过大影响其使用寿命。(The embodiment of the invention relates to the technical field of underground oil lifting, in particular to a submersible direct-drive special screw pump which comprises a power unit, a stator and a rotor, wherein: the stator comprises a cylinder body and a telescopic body which is molded on the inner wall of the cylinder body and is made of high-elasticity synthetic rubber, wherein an extrusion cavity is arranged in the telescopic body, and a first oil inlet hole and a second oil inlet hole are correspondingly arranged on the cylinder body and the telescopic body; the rotor is rotatably arranged in the extrusion cavity under the driving of the power unit, an acting part with a spiral structure is arranged outside the rotor, and the initial interference magnitude between the acting part and the extrusion cavity is-1.5 mm-0.5 mm; the rotating speed of the rotor is 50rpm-500 rpm. The embodiment of the invention has the beneficial effects that: the initial interference value is reduced or the clearance is increased, the starting torque is greatly reduced, the problem that the submersible direct-drive screw pump cannot be started is solved, and the phenomenon of large leakage, large volume and low efficiency is compensated by increasing the rotating speed; meanwhile, the deformation of the telescopic body is reduced, and the phenomenon that the service life of the telescopic body is influenced by overlarge deformation is avoided.)

1. The utility model provides a special single screw pump is directly driven to latent oil which characterized in that includes power unit, stator and rotor, wherein:

the stator comprises a cylinder body and a telescopic body which is molded on the inner wall of the cylinder body and is made of high-elasticity synthetic rubber, and an extrusion cavity which is used for the rotor to penetrate and has a double-spiral structure is arranged in the telescopic body;

the rotor is rotatably arranged in the extrusion cavity in the cross section of the stator under the driving of the power unit, an acting part of a spiral structure is arranged outside the rotor, and the initial interference between the acting part and the extrusion cavity is-1.5 mm-0.5 mm;

the rotating speed of the rotor is 50rpm-500 rpm.

2. The submersible direct drive dedicated single screw pump according to claim 1, wherein the barrel is made of metal.

3. The submersible direct-drive special single-screw pump according to claim 2, wherein the friction torque acting between the submersible direct-drive special single-screw pump and the telescopic body is M_frComprises the following steps:

M_fr＝f_rK(δ+δ₀) (1)

in formula (1): m_frThe friction torque between the stator and the rotor has the unit of N.m; f. of_r-the coefficient of friction between the stator and rotor; k is the rigidity of the stator rubber, and the unit is N/m; delta-the expansion capacity of the stator rubber under downhole conditions, in m; delta₀The initial interference of the stator rubber and the rotor, in m;

in any cross section of the extrusion cavity, the oil occupies the area of

4e×2R＝8eR＝4eD (2)

The displacement q of the submersible direct-drive special single screw pump is as follows every time the rotor rotates one circle:

q＝4eDT×10^-9 (3)

the theoretical discharge capacity of the submersible direct-drive special single-screw pump is

Q₁＝1440×4eDT×10^-7 (4)

In the formulae (2), (3) and (4), Q₁Theoretical displacement of pump, m³D (100 rpm); q-theoretical displacement of screw pump (rotor) per revolution, m³(ii) a e-eccentricity of the pump, the eccentricity of the single-screw pump of the existing structure; d, the diameter of a screw pump rotor is equal to 2R, (R is the radius of the screw pump rotor), and the diameter is mm; t-stator lead, T ═ 2T, (T is pitch), mm; n-the rotor speed of the screw pump, r/min. When the rated theoretical displacement of the pump is calculated, the rotating speed is usually 100 r/min;

the actual discharge capacity of the submersible direct-drive special single-screw pump is as follows:

Q＝Q₁·η＝4eDTnη/60 (5)

in the formula (5), η -volumetric efficiency of the single screw pump,%.

4. The submersible direct-drive special single-screw pump according to claim 1, wherein the rotation speed of the rotor is 50 rpm.

5. The submersible direct-drive special single-screw pump according to claim 1, wherein the rotation speed of the rotor is 500 rpm.

6. The submersible direct drive dedicated single screw pump according to claim 1, wherein the rotation speed of the rotor is 275 rpm.

7. The submersible direct drive dedicated single screw pump according to any of claims 1 to 6, characterized in that the initial interference of the extrusion chamber is-1.5 mm.

8. The submersible direct drive dedicated single screw pump according to any of claims 1 to 6, wherein the initial interference of the extrusion chamber is 0.5 mm.

9. The submersible direct drive dedicated single screw pump according to any of claims 1 to 6, wherein the initial interference of the extrusion chamber is-0.5 mm.

Technical Field

The invention relates to the technical field of underground oil lifting, in particular to a submersible direct-drive special screw pump.

Background

The underground screw pump consists of a rotor and a stator, wherein the rotor is the only moving part in the screw pump and is formed by performing finish machining and surface chromium plating on high-strength steel; the stator is made of high elastic synthetic rubber in the inner mold (inner wall) of the steel pipe, and has various rubber types according to different application occasions. Because the rotor and the stator form a series of mutually separated closed cavities when matched, when the rotor rotates, the closed cavities axially move from the suction end to the discharge end and disappear at the discharge end, and simultaneously the suction end forms a new closed cavity, and the liquid filled in the cavities is pushed to the discharge end from the suction end along with the movement of the closed cavities. The continuous formation, migration and disappearance of the closed cavity play a role in pumping liquid.

The submersible direct-drive screw pump technology provides new requirements for a screw pump, the current underground screw pump is difficult to meet the requirements, the running time is short, the problems mainly occur that the starting torque of the screw pump must be reduced below the starting torque (of the submersible permanent magnet motor) and certain margin is left because the driving parts of the submersible permanent magnet motor and the like are underground, the space is limited, the torque which can be provided by the submersible permanent magnet motor is limited, the starting torque of the screw pump is reduced, and the leakage is reduced for ensuring the volumetric efficiency, the stator and the rotor are in interference fit (because the starting rotating speed is low, the interference is large, the deformation of high-elasticity synthetic rubber is large, the service life of the synthetic rubber is influenced, the synthetic rubber is difficult to start under the submersible direct-drive screw pump lifting process, and the stator is immersed in an oil well and also swells to a certain extent, rendering activation more difficult.

In order to match and apply the submersible direct-drive screw pump technology, a submersible direct-drive special screw pump must be researched and designed, and the problems are solved.

Disclosure of Invention

In order to solve the problems that the underground space is limited, the torque provided by the submersible permanent magnet motor is limited, and the deformation of a telescopic body made of high-elasticity synthetic rubber is large, so that the service life is short, the embodiment of the invention provides a submersible direct-drive special single-screw pump which is characterized by comprising a power unit, a stator and a rotor, wherein:

the stator comprises a cylinder body and a telescopic body which is molded on the inner wall of the cylinder body and is made of high-elasticity synthetic rubber, and an extrusion cavity 122 which is used for the rotor to penetrate and has a double-spiral structure is arranged in the telescopic body;

the rotor is rotatably arranged in the extrusion cavity in the cross section of the stator under the driving of the power unit, an acting part of a spiral structure is arranged outside the rotor, and the initial interference between the acting part and the extrusion cavity is-1.5 mm-0.5 mm;

the rotating speed of the rotor is 50rpm-500 rpm.

Further, the cylinder is made of metal.

Further, the friction torque between the telescopic body and the acting force is M_frComprises the following steps:

M_fr＝f_rK(δ+δ₀) (1)

in formula (1): m_frThe friction torque between the stator and the rotor has the unit of N.m; f. of_r-the coefficient of friction between the stator and rotor; k is the rigidity of the stator rubber, and the unit is N/m; delta-the expansion capacity of the stator rubber under downhole conditions, in m; delta₀The initial interference of the stator rubber and the rotor, in m;

in any cross section of the extrusion cavity, the oil occupies the area of

4e×2R＝8eR＝4eD (2)

The displacement q of the submersible direct-drive special single screw pump is as follows every time the rotor rotates one circle:

q＝4eDT×10^-9 (3)

the theoretical discharge capacity of the submersible direct-drive special single-screw pump is

Q₁＝1440×4eDT×10^-7 (4)

In the formulae (2), (3) and (4), Q₁Theoretical displacement of pump, m³D (100 rpm); q-theoretical displacement of screw pump (rotor) per revolution, m³(ii) a e-eccentricity of the pump, the eccentricity of the single-screw pump of the existing structure; d, the diameter of a screw pump rotor is equal to 2R, (R is the radius of the screw pump rotor), and the diameter is mm; t-stator lead, T ═ 2T, (T is pitch), mm; n-the rotor speed of the screw pump, r/min. When the rated theoretical displacement of the pump is calculated, the rotating speed is usually 100 r/min;

the actual discharge capacity of the submersible direct-drive special single-screw pump is as follows:

Q＝Q₁·η＝4eDTnη/60 (5)

in the formula (5), η -volumetric efficiency of the single screw pump,%.

Preferably, the rotation speed of the rotor is 50 rpm.

Preferably, the rotation speed of the rotor is 500 rpm.

Preferably, the rotation speed of the rotor is 275 rpm.

Preferably, the initial interference of the extrusion cavity is-1.5 mm.

Preferably, the initial interference of the extrusion cavity is 0.5 mm.

Preferably, the initial interference of the extrusion cavity is-0.5 mm.

The embodiment of the invention has the beneficial effects that:

under the requirements of screw pumps with the same specification and the same displacement, the initial interference of the stator and the rotor can be reduced or the clearance of the stator and the rotor can be increased, so that the volumetric efficiency is reduced, and meanwhile, the rotating speed (50-500 rpm) is increased to realize the same displacement effect. Therefore, the core idea of the invention is to reduce the initial interference value or improve the clearance, greatly reduce the starting torque, solve the problem of the starting of the submersible direct-drive screw pump, and simultaneously improve the rotating speed to make up the phenomenon of large leakage and low volume efficiency.

Drawings

Fig. 1 is a schematic sectional structure view of an embodiment of a submersible direct-drive special single-screw pump.

In the figure:

11. a barrel; 111. a liquid inlet; 112. a liquid outlet; 12. a telescopic body; 121. an extrusion chamber;

2. a rotor; 21. an action part;

3. and a power unit.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.

Referring to fig. 1, the screw pump according to the embodiment of the present invention is a progressive displacement pump, which can be divided into single-head and multi-head according to the number of heads of the screw, and the electric submersible screw pump is a single-head screw pump commonly used in oil and gas fields, i.e., the rotor is a single screw and the stator is a double screw (determined by space meshing theory).

The screw pump optimizes the initial interference magnitude of the stator and the rotor, reduces the friction torque, and recognizes the friction torque M of the screw pump_frIs calculated as

M_fr＝f_rK(δ+δ₀) (1)

In the formula:

M_frfriction torque between stator and rotor, N.m

f_r-the coefficient of friction between the stator and the rotor,

k-stiffness of the stator rubber, N/m

Delta-expansion capacity of stator rubber under downhole conditions, m

δ₀Initial interference of stator rubber and rotor, m

It can be seen from the formula (1) that the friction torque can be obviously reduced by reducing the initial interference magnitude of the stator and the rotor, so that the submersible direct-drive screw pump system is easier to start.

But the interference reduction also has a certain limit, and the required lifting displacement and lift are ensured by matching with the rotating speed. When the screw pump rotates for one circle (2 pi), the oil in the closed cavity moves along the Z axis (the geometric central line of the screw pump) for a distance T-2T (T is the screw pitch). In any cross section, the area occupied by the oil is the difference between the sectional area of the bushing and the sectional area of the screw, namely:

4e×2R＝8eR＝4eD (2)

so that the pump has a displacement q of

q＝4eDT×10^-9 (3)

The theoretical displacement of the pump is:

Q₁＝1440×4eDT×10^-7 (4)

q in the formulae (2), (3) and (4)₁Theoretical displacement of pump, m³/d(100rpm)；

q-theoretical displacement of screw pump (rotor) per revolution, m³；

e-eccentricity of the pump, the eccentricity of the single-screw pump of the existing structure;

d, the diameter of a screw pump rotor is equal to 2R, (R is the radius of the screw pump rotor), and the diameter is mm;

t-stator lead, T ═ 2T, (T is pitch), mm;

n-the rotor speed of the screw pump, r/min. When calculating the rated theoretical displacement of the pump, the rotating speed is usually 100 r/min.

The actual displacement of the single-screw pump is as follows:

Q＝Q₁·η＝4eDTnη/60 (5)

in the formula (5), η -volumetric efficiency of the single screw pump,%. The volumetric efficiency is affected by the difference in the interference or clearance values of the timing rotor during design.

It can be seen from the formula (5) that under the requirements of screw pumps with the same specification and the same displacement, the initial interference of the stator and the rotor can be reduced or the clearance of the stator and the rotor can be increased to reduce the volumetric efficiency, and the rotating speed (50-500 rpm) is increased to realize the same displacement effect. Therefore, the core idea of the invention is to reduce the initial interference value or improve the clearance, greatly reduce the starting torque, solve the problem of the starting of the submersible direct-drive screw pump, and simultaneously improve the rotating speed to make up the phenomenon of large leakage and low volume efficiency.

In particular, it comprises a power unit 3, a stator 1 and a rotor 2, wherein:

the stator comprises a cylinder body 11 and a telescopic body 12 which is molded on the inner wall of the cylinder body and is made of high-elasticity synthetic rubber, wherein a suction inlet of a double-helix extrusion cavity 122 pump for the rotor to pass through is arranged in the telescopic body and is a liquid inlet 111, and the opposite end of the liquid inlet is a liquid outlet 112;

the rotor is rotatably arranged in the extrusion cavity in the cross section of the stator under the driving of the power unit, an acting part 21 with a spiral structure is arranged outside the rotor, and the initial interference between the acting part and the extrusion cavity is-1.5 mm-0.5 mm;

the rotating speed of the rotor is 50rpm-500 rpm.

Under the condition that the screw pump increases the eccentric operation rotating speed of the rotor, rapid abrasion and large vibration can be caused, and the service life is reduced, so the invention further adopts the design of long lead and low eccentricity. Compared with the existing screw pump, the screw profile is lengthened to 1.2-2 times, the eccentricity is reduced to 2-6 mm, the volume of a sealing cavity formed by the lead of a single stator and rotor is unchanged, namely the nominal model of the pump is unchanged, the specific size is related to the actually designed pump type, the eccentricity is reduced, and the vibration is greatly reduced.

The pump type is designed conventionally, such as a certain known brand ST4.0 pump type, the diameter of a rotor is phi 29mm, the diameter of a stator is phi 28.9mm, the interference is 0.1mm, the lead is 91mm, and the eccentricity is 3 mm.

The principle of lifting oil of the screw pump related by the invention is the same as that of a common screw pump, but the pump system has the outstanding characteristics of reducing the initial interference magnitude of the stator and the rotor, ensuring that the volumetric efficiency and single-stage bearing are not affected under the high-speed operation condition, reducing the friction torque, being easy to start, reducing the friction wear and having small service life, thereby improving the working reliability of the system of the pump, and having more outstanding advantages especially under the conditions that the power of the electric submersible direct-drive screw pump system is limited and the starting torque is lower.

In conclusion, under the condition that the composition and the principle of the screw pump are not changed, the problems in the application of the submersible direct-drive screw pump are solved by designing the stator and the rotor which are separated from the conventional size requirements, and the special high-rotating-speed, easy-starting and small-vibration screw pump suitable for the submersible direct-drive screw pump lifting system is realized.

The telescopic body 2 is made by injecting glue (high elasticity synthetic rubber) into a mould and vulcanizing, then is fixed with a cylinder 21 made of metal materials through rivets and bonding, and then is matched with the matched rotor 1, and the rotor performs planetary motion in the stator to finish the suction and discharge of media.

It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicating the directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The terms "comprises," "comprising," or any other similar term are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.