WO2024144472A1

WO2024144472A1 - A new stator assembly configuration for progressive cavity pumps

Info

Publication number: WO2024144472A1
Application number: PCT/TR2022/051656
Authority: WO
Inventors: Süleyman YİĞİT; Levent KANTAR; Bozkurt Bariş DEMİR; Ender SAMUR
Original assignee: Polat Makina Sanayi Ve Ticaret AS
Current assignee: Polat Makina Sanayi Ve Ticaret AS
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2024-07-04
Anticipated expiration: 2025-06-28
Also published as: EP4627220A1

Abstract

The invention relates to the design and assembly of the stator, stator casing and stator assembly cover used in progressive cavity pumps (PCP) which can pump all liquids, liquid-solid or liquid-gas mixtures even if they have different density, concentration and viscosity values in different industries such as petroleum, food, wastewater treatment.

Description

A NEW STATOR ASSEMBLY CONFIGURATION FOR PROGRESSIVE CAVITY PUMPS

Technical Field

The invention relates to a stator assembly configuration used in progressive cavity pumps.

In particular, the invention relates to progressive cavity pumps (PCP) that can pump all liquids, liquid-solid or liquid-gas mixtures even if they have different density, concentration and viscosity values in different industries such as petroleum, food, wastewater treatment.

The invention relates to innovations in the design and assembly of a stator, stator casing and stator assembly cover.

Prior Art

Today, pumps are used in various fields of industry to transfer difficult fluids from one place to another. For example, in the food industry, progressive cavity pumps are preferred for the transfer of fluids such as chocolate and cream with low vibration without causing any change in the product structure.

In the progressive cavity pumps in the current technique, the steel rotor part rotates inside the stator part, which is generally made of rubber material, by constantly crushing it, so these parts wear out in a short time and need to be replaced. In order to remove these parts and replace them with new ones, the pump must be completely removed from the installation line to which it is connected and disassembled. These operations take a lot of time, require labor and require physical space in the working environment. This means long and laborious maintenance periods.

In the prior art, due to the nature of the pump, the rotor and stator elements wear out rapidly and need to be replaced. The stator part is in one piece and is a composite material glued into a metal tube. Since a composite material is not suitable for recycling, it is environmentally disadvantageous. In addition, the parts used in the assembly of progressive cavity pumps and referred to as studs connect the outlet flange and the casing and compress the stator material between them. Installation of the pump with studs is not practical as it requires physical strength.

As a result of the research on the subject in the literature, a document with publication number EP2944819B1 was found. The document relates to a progressive cavity pump comprising a rotor extending from a drive end to a free end along its longitudinal axis, a stator casing extending from a stator inlet opening to a stator outlet opening and having an internal volume formed to receive the rotor, a drive assembly (motor and reducer) with a drive shaft coupled to the rotor for the transmission of torque, a universal joint for the transmission of torque between the drive shaft and the rotor, a pump casing assembly for the inlet of the material and an outlet flange positioned behind the rotor in the direction of flow. There is no mention of an improvement in the present art to allow easy assembly/disassembly of the stator into the stator casing and the stator assembly into the pump.

Another document encountered on the subject is the document with the publication number US10648337B2. The document relates to a progressive cavity pump having at least one stator made of elastic material and a rotor rotatable or rotatably mounted inside the stator, where the stator can be reliably reconnected, preferably even under higher loads. There is no mention of an improvement in the present art to allow easy assembly/disassembly of the stator into the stator casing and the stator assembly into the pump.

Consequently, due to the above-mentioned drawbacks and the fact that existing solutions have room for improvement, it was deemed necessary to develop an improvement in the relevant technical field.

Purpose of the Invention

The invention is inspired by existing situations and aims to solve the above-mentioned problems.

The main purpose of the invention is to reduce the friction surface and therefore the frictional force by means of the bumps on the stator and the optimized radial clearance values between the stator and the stator casing, thus enabling easy disassembly and assembly of the stator casing. The other purpose of the invention is to prevent the stator casing from positioning the stator and moving in the direction of rotation by means of longitudinal axial guide rails reinforced with steel shafts on the stator and longitudinal axial grooves on the inner surface of the stator casing.

A further purpose of the invention is to provide a stator assembly cover for sealing and connecting the stator and stator casing between the casing assembly and the outlet flange.

In order to fulfill the above-mentioned purposes, the invention is a progressive cavity pump to pump all liquids, liquid-solid or liquid-gas mixtures, even if they have different density, concentration and viscosity values, in different industries such as petroleum, food, wastewater treatment, comprising:

• A motor-reducer that provides the power the machine needs,

• A pump casing assembly, the part where the fluid enters the pump,

• A lantern casing connecting the motor-reducer and the pump casing assembly,

• A drive shaft that transmits the rotational motion received from the reducer,

• A cardan shaft that transmits the rotational motion received from the drive shaft,

• A rotor that rotates eccentrically with the drive from the cardan shaft and creates flow and pressure,

• Connection pins that connect both the drive shaft to cardan shaft and the cardan shaft to rotor,

• An outlet flange, the part where the fluid exits the pump and characterized by comprising;

A stator reinforced with at least one steel shaft that allows the rotor to rotate eccentrically inside it and to move the fluid with flow and pressure, • A one-piece stator casing that contains the stator and protects it against environmental factors,

• At least one guide rail on the outer surface of the stator, which allows the stator to hold the stator casing and allows the stator to be easily inserted and removed from the stator casing and prevents it from moving in the direction of rotation,

• At least one groove on the inside of the stator casing, which has a form compatible with the guide rails to hold the guide rails and thus ensures that the stator is firmly attached to the stator casing,

• At least one stator assembly cover at both ends of the stator, providing sealing and connection between the stator and the outlet flange and between the stator and the pump casing assembly.

The structural and characteristic features and all advantages of the invention will be more clearly understood with the following figures and the detailed description with references to these figures, and therefore the evaluation should be made by taking these figures and detailed description into consideration.

Figures to Help Understanding of the Invention

Figure 1 is a top perspective view of a progressive cavity pump.

Figure 2 is a front view of the stator.

Figure 3 is a close-up view of the bumps of the stator.

Figure 4 is a cross-sectional view of the stator.

Figure 5 is an exploded view of the stator assembly.

Figure 6 is frontal and isometric views of the stator casing.

Figure 7 is a cross-sectional view of the stator assembly and outlet flange.

Figure 8 is a cross-sectional view of the stator assembly and service casing.

Figure 9 is a cross-sectional view of the progressive cavity pump. Description of Part References

1. Progressive cavity pump

10. Motor-reducer

12. Drive shaft

13. Cardan shaft

20. Lantern casing

30. Rotor

31. Rotor connection pin

40. Stator assembly

41. Stator

42. Stator assembly cover

43. Stator casing

44. Guide rail

45. Groove

46. Shaft

47. Bolt

48. Bumps

50. Pump casing assembly

51. Pump casing

52. Service casing

60. Outlet flange

Detailed Description of the Invention

In this detailed description, preferred embodiments of the progressive cavity pump (1 ) which is subject to the invention, are described only for the purpose of a better understanding of the subject matter. Since the progressive cavity pump (1 ) which is subject to the invention, can pump almost all liquids, liquid - solid, liquid - gas mixtures even if they have different density, concentration and viscosity values, it can be used in industries such as petroleum, food, waste water treatment. The progressive cavity pump (1 ), which has a wide range of applications, basically consists of a motor-reducer (10), drive shaft (12), cardan shaft (13), lantern casing (20), rotor (30), stator (41 ), pump casing (51 ), service casing (52) and outlet flange (60).

The motor-reducer (10) in the progressive cavity pump (1 ), which is subject to the invention, provides the power required by the machine. The fluid enters the pump through the pump casing (51 ). The lantern casing (20) connects the motor-reducer (10) and the pump casing (51 ). There is a drive shaft (12) which transfers the rotary motion received from the reducer. The cardan shaft (13) provides the transmission of the rotational motion received from the drive shaft (12) to the rotor (30). The rotor (30) rotates eccentrically inside the stator (41 ), creating flow and pressure through the closed chambers it forms. The internal geometry of the stator (41 ) is suitable for the rotation of the rotor (30).

The most important purpose of the progressive cavity pump (1 ) which is subject to the invention, is to enable the stator (41 ) to be inserted and removed into the stator casing (43) with less force during assembly/disassembly. The stator casing (43) is in one piece and has a closed geometry, and the stator (41 ) can be removed and inserted into the stator casing (43) by means of the bumps on it and the appropriate hollow structure between them. The stator (41 ) is not a composite material obtained by gluing rubber into a metal tube as in the current method but is surrounded by a removable one-piece stator casing.

The clearance between the stator (41 ) and the stator casing (43) have optimized values for easy assembly and disassembly. If the clearance is too large, the stator casing (43) will not be able to fully wrap the stator (41 ) and prevent the stator from moving. In addition, in case of high pressure operation, the stator geometry, which has an elastic structure, will stretch outward in the radial direction and performance loss may occur in the pump. If the clearance is small, excessive force will have to be applied due to friction during the insertion and removal of the stator to the stator casing. For this reason, bumps (48) of different geometries should be provided on the stator to optimize the clearance between the stator and the stator casing and for easier disassembly and assembly. The width, height and geometry of these bumps (48) have different values and can gradually increase or decrease. The bumps (48) can be located at any point on the outer surface of the stator and can be in the form of a continuous line, helical line, dashed line, point and/or different geometries and combinations thereof.

These bumps (48) ensure that the cylindrical surfaces of the stator (41 ) do not contact the stator casing (43) completely, but only in thin lines and/or small surfaces. This results in a reduced friction surface. Fewer frictional surfaces facilitate the assembly and disassembly of the stator (41 ) to the stator casing (43).

There are guide rails (44) on the stator and grooves (45) in the stator casing (43) which are compatible with these guide rails. These guide rails (44) prevent the stator from rotating within the stator casing and ensure its angularly correct positioning. These guide rails can be on any surface of the stator, one or more in number, of different widths and heights, circular, rectangular or in different geometric forms in terms of cross-sectional geometry. Grooves (45) are located on the inside of the stator casing (43). These grooves have a cross-sectional shape compatible with the cross-sectional shape of the guide rails (44) and thus ensure that the stator is firmly attached to the stator casing and prevent the rotor from rotating the stator.

The invention further comprises at least one stator assembly cover (42) at both ends of the stator (41 ), which provides sealing and connection between the stator (41 ) and the outlet flange (60), and between the pump casing assembly (50) and the stator (41 ). In addition, the rubber stator includes one or more shafts (46) having tapped ends thereof. These shafts (46) provide the connection to the stator assembly cover (42) and also contribute to the strength of the stator. These shafts are positioned in the direction of the longitudinal axis of the stator and protruding radially from the stator. The stator pitch length must be compatible with the rotor pitch length, otherwise the pump performance deteriorates. The use of stator assembly covers (42) prevents the pitch length from changing as they significantly eliminate the compression effect on the stator in the longitudinal axial direction. These stator assembly covers (42) also ensure sealing.

Claims

1. A progressive cavity pump (1 ) which is able to pump all liquids, liquid-solid or liquid-gas mixtures even if they have different density, concentration and viscosity values in different industries such as petroleum, food, wastewater treatment, comprising:

• A motor-reducer (10) that provides the power required by the machine,

• A pump casing (51 ), the part where the fluid enters the pump,

• A lantern casing (20) connecting the motor-reducer (10) and the pump casing (51 ),

• A drive shaft (12) transmitting the rotary motion received from the reducer,

• A cardan shaft (13) transmitting the rotary motion received from the drive shaft (12),

• An eccentrically rotating rotor (30) driven by a cardan shaft, generating flow and pressure,

• Rotor connection pin (31 ), which connects both the drive shaft (12) to cardan shaft (13) and the cardan shaft (13) to rotor (30),

• An outlet flange (60) where the fluid exits the pump and characterized by comprising;

• A stator that allows the rotor to rotate eccentrically inside it, moving the fluid with flow rate and pressure (41 ),

• A stator casing (43) which contains the stator (41 ), prevents the rotational movement of the stator (41 ) and protects it against environmental factors,

• At least one bump (48) on the outer surface of the stator (41), which enables the stator (41 ) to hold the stator casing (43) and allows the stator to be easily inserted and removed from the stator casing due to the reduced friction surface, • At least one guide rail (44) on the stator, which allows the stator casing (43) to position the stator (41 ) and prevents it from moving in the direction of rotation,

• At least one shaft (46) inserted in the stator, which increases the strength of the stator and enables its assembly with the surrounding parts,

• At least one groove (45) positioned inside of the stator casing (43), having a cross-sectional form compatible with the cross-sectional form of the guide rails (44) and thus ensuring that the stator is securely attached to the stator casing, • Stator assembly cover (42) at both ends of the stator (41 ), providing connection and sealing between the stator (41 ) and the outlet flange (60) and between the stator (41 ) and the pump casing assembly (50).

2. The progressive cavity pump (1 ) according to claim 1 , characterized by comprising at least one bolt (47) for connecting the stator assembly cover (42) to the stator (41 ) by means of at least one shaft (46).