A step-by-step wellhead fine filtration device

Abstract

The present invention relates to a step-by-step wellhead fine filtration device, which belongs to the field of wellhead filtration devices. The device includes a sealed tank body, a step-by-step series filtration structure and a ball pitching mechanism. The step-by-step series filtration structure is connected in series by an upper support plate, a support filter cartridge and a plurality of step-by-step sliding sleeve groups through support ball clamping, and the bottom is connected to the bottom plate through a pulling wire and filter cloth. The ball pitching mechanism includes a top cover, a ball pitching cover, a main gear rod, a sub-gear rod and a ball sleeve, and balls with gradually increasing diameters are placed on the ball sleeve. When the ball is put into the corresponding ball seat, the ball seat is pressed down, driving the retaining spring to hook the slide cylinder and move it down, so that the support ball is disengaged, completing the separation of the sleeve and the upper-level locking ball sleeve, unlocking and opening the next-level filtration unit, forming a step-by-step relay mechanism for sewage filtration. The structural design of the present invention is reasonable, can achieve step-by-step fine filtration, and improve filtration efficiency and service life.

Description

Technical Field

[0001] The invention relates to the field of wellhead filtering devices, and in particular to a step-by-step wellhead fine filtering device. Background Art

[0002] During oilfield development, water injection wells are key equipment for maintaining reservoir pressure and enhancing crude oil recovery. Their operational performance directly impacts oilfield productivity. The quality of the injected water is crucial. Excessive impurity levels can easily clog the reservoir, severely reducing well productivity and shortening the oilfield's production cycle. Currently, there are two main types of filtration devices commonly used in oilfield water injection wells. The first type is a primary filtration device, which features a relatively simple structure and relies solely on a single filter component to intercept impurities, requiring frequent filter replacement.

[0003] Another type is multi-stage parallel filtration devices. While increasing the number of filter units improves filtration efficiency and extends the filter component replacement cycle, they also have numerous drawbacks. In terms of space usage, these devices are bulky, making installation difficult and significantly increasing construction costs. Furthermore, in terms of resource utilization, multiple filter units operate simultaneously, and if one unit stops functioning due to a blockage or malfunction, the entire parallel system must be shut down for maintenance.

[0004] Furthermore, the drawbacks of multi-stage, parallel filtration systems become even more pronounced when faced with the need for centralized filtration of highly contaminated wastewater during a specific period. Because all parallel filter units simultaneously receive wastewater, impurities in the wastewater rapidly accumulate within each unit, causing increased blockage and a continuously increasing pressure differential between the inlet and outlet ports. Once multiple filter units become severely clogged, the filtration efficiency of the entire system plummets. Traditional solutions often rely on frequent cleaning or replacement of filter units, which not only increases labor and consumable costs but also results in extended downtime, severely impacting the continuity of oilfield water injection operations.

[0005] In the process of oil and gas well development, ball-dropping mechanisms and filtering systems are applied to various types of downhole tools. For example, CN102979494B discloses a ball-dropping opening type multi-cluster sliding sleeve, which can realize the opening of multiple multi-cluster sliding sleeves by one ball-dropping, providing a maximum circulation channel for the production of long horizontal well sections. The rotatable and salvageable ball-dropping fracturing sliding sleeve disclosed in CN213392120U is connected to the bottom thread of the opening sliding sleeve through a ball seat, and the ball seat and the fracturing ball are matched in a step-by-step manner. Different from the present invention, the above-mentioned ball-dropping opening mechanism is mostly suitable for multi-stage fracturing operations in oil fields. After the above-mentioned sliding sleeve is opened, the upper and lower main structures are still connected by an external pipe, but the fracturing hole leaks out. The above-mentioned ball-dropping adopts an external ball-dropping device and is now connected to the wellhead oil pipe or casing gate.

[0006] In sharp contrast, the step-by-step series filtration structure adopted by the present invention has significant advantages. When treating sewage at the wellhead, each level of the filtration unit of this structure operates independently and has a compact structure. When a certain level of filtration unit is close to being blocked due to impurity accumulation, the internal ball-casting mechanism can trigger the complete separation of the upper and lower level sliding sleeve bodies, open the next level of filtration unit, and guide the sewage to the new filtration unit for treatment, thereby avoiding the continued deterioration of the blockage and the excessive increase in the inlet and outlet pressure difference. This method can not only effectively ensure the stable operation of the filtration system under highly polluted sewage conditions, but also make full use of the filtration capacity of each filtration unit to avoid the decline in efficiency or failure of the entire system due to local blockage.

[0007] In summary, there is an urgent need for a wellhead filtering device with a simple structure, easy operation, and the ability to achieve step-by-step fine filtration to solve the problems existing in the prior art. Summary of the Invention

[0008] In order to solve the technical problems in the prior art that the filtering device requires frequent replacement of the filter cloth when the filter cloth effect decreases, the operation is complicated and inefficient, and the lack of a multi-stage filtering switching mechanism makes it impossible to achieve continuous and stable filtering operations, the present invention provides a step-by-step wellhead fine filtering device.

[0009] The technical solution adopted by the present invention to solve its technical problems is: a step-by-step wellhead fine filtering device, including a sealed tank body, a step-by-step series filtering structure and a ball-casting mechanism, the step-by-step series filtering structure includes an upper support plate 5, the lower outer ring of the upper support plate 5 presses the support filter cartridge 6, and the N-stage series connection is achieved through the center hole steel ball groove and the steel ball groove of N step-by-step sliding sleeve groups 8, through the support ball 806 clamping, the bottom step-by-step sliding sleeve group 8 is connected to the bottom plate 7 through the pulling wire 15 and the filter cloth 16, and the inner hole of the ball seat 802 of each step-by-step sliding sleeve group 8 increases in diameter from bottom to top , adapted to the balls 13 with gradually increasing diameters in the ball pitching mechanism, when the ball pitching mechanism throws the ball 13 into the corresponding ball seat 802, the ball seat 802 is pressed down, driving the retaining spring 805 to hook the slide 804 and move it down, and the supporting ball 806 is disengaged, completing the separation of the sleeve 807 from the locking ball sleeve 801 of the upper level, completing the unlocking and opening the next level of filter unit, forming a step-by-step relay mechanism for sewage filtration, and the slide 804 that has moved down is seated in the locking ball sleeve 801 of this level, keeping the height of the step-by-step slide group 8 unchanged after the drop, ensuring that each level of filter cloth 16 can fully carry out filtration.

[0010] The step-by-step sliding sleeve group 8 of each level includes a sleeve 807, the lower end of the center of the sleeve 807 is threadedly connected to the locking ball sleeve 801, the locking ball sleeve 801 is designed with a steel ball groove, and a sealing groove is machined inside and outside the tube, and an O-ring is inserted into the sealing groove; a slide 804 is placed in the center hole of the sleeve 807, and a protruding ring at the bottom of the slide 804 can lift the sleeve 807. A plurality of oblique circular holes are drilled on the upper part of the slide 804 and a supporting ball 806 is placed therein. A ball seat 802 is inserted into the interior of the slide 804, and a pin 803 is inserted into the bottom of the ball seat 802 to lock the two parts; the inserted ball seat 802 blocks the supporting ball 806 from moving toward the central axis of the slide 804, so that a part of the supporting ball 806 is stuck in the oblique circular hole of the slide 804, and the other part is stuck in the steel ball groove of the locking ball sleeve 801 of the step-by-step sliding sleeve group 8 of the upper level, thereby realizing the step-by-step series filtering and locking between the step-by-step sliding sleeve groups 8 of each level.

[0011] The number of the step-by-step sliding sleeve groups 8 is N, where N is an integer of 2-10.

[0012] The ball pitching mechanism includes a top cover 1, which is provided with a ball pitching observation structure and a ball pitching transmission assembly. A ball pitching cover 10 is fixed upside down on the outer ring of the top cover 1 and locked with screws. The main gear rod 9, the sub-gear rod 11 and the ball sleeve 12 are engaged with each other. In the N+1 cylindrical ball grooves on the outer ring of the ball sleeve 12, N ball grooves are placed to accommodate balls 13 with gradually increasing diameters. Rotating the handwheel 14 can drive the ball sleeve 12 to rotate, so that the balls 13 fall into the tank body 4 through the outlet of the ball pitching cover 10.

[0013] The ball pitching observation structure has a conical hole drilled in the top cover 1 above the ball pitching cover 10. A sealing rubber ring is inserted into the conical hole, and a conical high-pressure resistant glass 101 is inserted into the conical hole. The high-pressure resistant glass 101 is clamped with a screw locking ring cover 102, which is used for the operator to visually observe the ball pitching situation of the device.

[0014] The filter cloth 16 is a flexible filter material, and has a pressure ring on the top and bottom to form a disposable detachable accessory. After the screw is passed through the reserved circular hole of the pressure ring of the filter cloth 16, it is locked with the upper support plate 5, the sleeve plate 807 and the bottom plate 7 to connect N+1 filter cloths 16 in a ring segment.

[0015] The sealed tank body includes a tank body 4, which is covered with a top cover 1 to form a closed filtration space. A sealing rubber gasket 3 is provided between the top cover 1 and the tank body 4. Multiple quick-release bolts 2 are arranged on the outer ring of the top of the tank body 4. Tightening the quick-release bolts 2 compresses the sealing rubber gasket 3, completing the closure and sealing of the device. The upper portion of the tank body 4 is provided with a water inlet 401 for introducing wastewater to be filtered; the lower portion is provided with a water outlet 402 for discharging filtered clean water. Below the water inlet 401 inside the tank body 4, a circular metal ring is welded to form a support platform 403 to provide stable support for the subsequent filter unit assembly.

[0016] The support filter cartridge 6 is inserted into the tank body 4 from above, and its top shoulder is placed on the support platform 403 by its own weight. The body and bottom of the support filter cartridge 6 are made of high-strength filter mesh to provide reliable support for the filter cloth 16 after it is opened.

[0017] The upper support plate 5 is in a conical funnel shape, which is used to facilitate the ball 13 to fall smoothly into the center hole of the upper support plate 5.

[0018] The bottom of the main gear rod 9 is inserted into the preset circular hole groove of the pitching cover 10 to achieve bottom fixation, and its upper part passes through the top cover 1; a protruding sealing groove is provided on the top cover 1, and the rod sealing ring 105 is inserted into the protruding sealing groove, and the pressure plate 104 is tightened with a screw to compress the rod sealing ring 105 to complete the sealing of the main gear rod 9.

[0019] The upper end of the main gear rod 9 is a hexagonal rod, which is convenient for cooperating with the handwheel 14. The top of the hexagonal rod is a threaded rod. After the handwheel 14 is inserted into the hexagonal rod, it is threaded and fixed by the nut 103; the outer gear of the main gear rod 9 is engaged with the inner gear of the ball disc 12; the sub-gear rod 11 is inserted into the preset ring sleeve of the top cover 1 and the pitching cover 10 to achieve upper and lower fixation and rotation, and its outer gear is also engaged with the inner gear of the ball disc 12.

[0020] The N+1th ball slot of the ball tray 12 is an empty slot, and the balls 13 in the ball slot are arranged circumferentially in increasing steps according to their diameters. When the hand wheel 14 is rotated, the hand wheel 14 drives the ball tray 12 to rotate through the main gear rod 9. When the hand wheel 14 rotates one circle, the ball tray 12 rotates one ball slot, and the balls 13 in the ball slot fall into the interior of the tank body 4 through the outlet of the ball throwing cover 10.

[0021] The diameter of the adapted ball 13 is larger than the inner hole size of the ball seat 802 of this level (105mm-5mm), and smaller than the inner hole size of the ball seat 802 of the upper level (105mm-5mm).

[0022] The length of the pulling wire 15 is 80%-95% of the unfolded length of the filter cloth 16 .

[0023] The beneficial effects of the present invention are that the device can automatically replace the filter cloth according to the working state of the filter cloth. When the filtering effect of the filter cloth decreases, the filter cloth can be replaced without manual intervention by observing the inlet and outlet pressure difference or the number of filtering days, thereby improving the continuity and stability of the filtering operation; the pressure difference between the wellhead and the outlet is used as the power source, and the main gear rod drives the ball disc to rotate by turning the hand wheel, so that the ball falls into the ball seat of the step-by-step sliding sleeve group, and the pressure difference is used to generate thrust, and the pin is cut to move the ball seat downward, so that the current level filter cloth is folded and the next level filter cloth is unfolded at the same time. The filter cloth switching can be completed without additional energy, and the structure is simple and reliable; the step-by-step sliding sleeve group design is adopted, and the slide cylinder moves down to the locking ball sleeve to ensure that the height of the step-by-step sliding sleeve group will not increase during the filter cloth replacement process, thereby realizing the switching function of multi-stage filtration, extending the continuous working time of the device, and improving the filtration efficiency; the overall design cleverly utilizes mechanical principles to reduce maintenance costs and operation difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0025] Figure 1 This is a structural diagram of a step-by-step wellhead fine filtration device;

[0026] Figure 2 This is a schematic diagram of a step-by-step sliding sleeve assembly of a step-by-step wellhead fine filtration device;

[0027] Figure 3 This is a schematic diagram of a ball pitching mechanism for a step-by-step wellhead fine filtration device;

[0028] Figure 4 This is a diagram of the step-by-step opening operation of a step-by-step wellhead fine filtration device.

[0029] Description of reference numerals:

[0030] 1. Top cover; 101. High-pressure-resistant glass; 102. Ring cover; 103. Nut; 104. Pressure plate; 105. Rod sealing ring; 2. Quick-release bolts; 3. Sealing rubber pad; 4. Tank body; 401. Water inlet; 402. Water outlet; 403. Support platform; 5. Upper support plate; 6. Support filter cartridge; 7. Bottom plate; 8. Step-by-step sliding sleeve assembly; 801. Locking ball sleeve; 802. Ball seat; 803. Pin; 804. Sliding cylinder; 805. Circlip; 806. Support ball; 807. Sleeve disc; 9. Main gear rod; 10. Ball pitching cover; 11. Sub-gear rod; 12. Sleeve disc; 13. Ball; 14. Handwheel; 15. Lifting wire; 16. Filter cloth. DETAILED DESCRIPTION

[0031] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0032] Example

[0033] like Figure 1-4 The figure shows a step-by-step wellhead fine filtration device, comprising a sealed tank, a step-by-step series filtration structure, and a ball-dropping mechanism. The sealed tank houses the entire filtration system and ensures its tightness. The step-by-step series filtration structure is the core component of the device, achieving step-by-step fine filtration of wastewater. The ball-dropping mechanism is the key mechanism for controlling the initiation of the filtration process.

[0034] The sealed tank body includes a tank body 4, which is covered with a top cover 1 to form a closed filtration space. A sealing rubber gasket 3 is provided between the top cover 1 and the tank body 4, and a plurality of quick-release bolts 2 are arranged on the outer ring of the top of the tank body 4. Tightening the quick-release bolts 2 can compress the sealing rubber gasket 3 to complete the closure and sealing of the device. A water inlet 401 is provided at the top of the tank body 4 for introducing sewage to be filtered; a water outlet 402 is provided at the bottom for discharging filtered clean water. Below the water inlet 401 inside the tank body 4, an annular metal ring is welded to form a support platform 403 to provide stable support for the subsequent filter unit assembly.

[0035] The support filter cartridge 6 is inserted into the tank body 4 from above, and its top shoulder is placed on the support platform 403 by its own weight. The body and bottom of the support filter cartridge 6 are made of high-strength filter mesh to provide reliable support for the filter cloth 16 after it is opened.

[0036] The upper support plate 5 is in a conical funnel shape, which is used to facilitate the ball 13 to fall smoothly into the center hole of the upper support plate 5.

[0037] The progressive series filtration structure includes an upper support plate 5, whose lower outer ring compresses the support filter cartridge 6. Through the central hole steel ball groove and the steel ball grooves of N-1 progressive sliding sleeves 8, the support balls 806 engage, creating an N-stage series connection. The upper support plate 5 is made of a high-strength alloy material, providing sufficient rigidity and strength to support the entire filtration system. The support filter cartridge 6 is mounted below the upper support plate 5 and is held in place by the outer ring of the upper support plate 5, forming a stable support structure.

[0038] The bottom, step-by-step sliding sleeve assembly 8, is connected to the sinking plate 7 via a pull wire 15 and filter cloth 16. The inner diameter of the ball seats 802 in each step-by-step sliding sleeve assembly 8 increases from bottom to top, accommodating the increasingly larger diameter balls 13 in the ball-dropping mechanism. The sinking plate 7, located at the very bottom of the filtration system, supports the bottommost filter cloth 16 and is connected to the pull wire 15, forming a complete filtration unit.

[0039] The number of step-by-step sliding sleeve assemblies 8 is N, where N is an integer between 2 and 10. In this embodiment, N is 5, meaning five steps of step-by-step sliding sleeve assemblies 8 are provided. Each step-by-step sliding sleeve assemblies 8 includes a sleeve 807, the lower center end of which is threadedly connected to a locking ball sleeve 801. The locking ball sleeve 801 is designed with a steel ball groove and sealing grooves machined inside and outside the tube, with O-rings inserted into the sealing grooves. A slide 804 is placed in the center hole of the sleeve 807. A protruding ring at the bottom of the slide 804 supports the sleeve 807. Multiple oblique circular holes are drilled in the upper portion of the slide 804, into which support balls 806 are placed. A ball seat 802 is inserted into the interior of the slide 804, and a pin 803 is inserted at the bottom of the ball seat 802 to lock the two parts.

[0040] The inserted ball seat 802 blocks the movement of the support ball 806 toward the center axis of the slide 804, causing one portion of the support ball 806 to be lodged in the oblique circular hole of the slide 804 and the other portion to be lodged in the steel ball groove of the locking ball sleeve 801 of the upper level sliding sleeve assembly 8, thus achieving step-by-step series filtration locking between each level of the sliding sleeve assembly 8. This design ensures that each level of filtration unit remains locked under normal operating conditions and is unlocked only under specific conditions, achieving sequential control of the step-by-step filtration.

[0041] The filter cloth 16 is a flexible filter material with upper and lower pressure rings, forming a disposable, removable accessory. Screws are inserted through the reserved circular holes in the pressure rings of the filter cloth 16 and then secured to the upper support plate 5, sleeve plate 807, and sink plate 7, forming a circular segmented connection of N+1 filter cloths 16. Made of high-efficiency filter material, the filter cloth 16 offers excellent filtration performance and sufficient mechanical strength, effectively filtering impurities from wastewater. The pressure ring design ensures uniform force distribution on the filter cloth 16, preventing deformation or damage during the filtration process.

[0042] The length of the lifting wire 15 is 80%-95% of the extended length of the filter cloth 16. This design ensures that the filter cloth 16 maintains proper slack during the filtration process, forming an ideal filtration pattern and improving filtration efficiency. The lifting wire 15 is made of corrosion-resistant material, with sufficient strength and toughness to withstand long-term use in harsh environments.

[0043] The pitching mechanism includes a top cover 1, which is provided with a pitching observation structure and a pitching transmission assembly. The pitching cover 10 is fixed upside down on the outer ring of the top cover 1 and locked with screws. The main gear rod 9, the sub-gear rod 11 and the ball disc 12 are engaged with each other. In the N+1 cylindrical ball grooves on the outer ring of the ball disc 12, N ball grooves are placed to place balls 13 with gradually increasing diameters. Rotating the handwheel 14 can drive the ball disc 12 to rotate, so that the ball 13 falls into the tank body 4 through the outlet of the pitching cover 10.

[0044] The pitching observation structure has a conical hole drilled in the top cover 1 above the ball outlet of the pitching cover 10. A sealing rubber ring is inserted into the conical hole, and a conical high-pressure resistant glass 101 is inserted into the conical hole. The high-pressure resistant glass 101 is clamped with a screw locking ring cover 102, which is used for the operator to visually observe the pitching situation of the device.

[0045] The bottom of the main gear rod 9 is inserted into the preset circular hole groove of the pitching cover 10 to achieve bottom fixation. Its upper part passes through the top cover 1, which has a protruding sealing groove. The rod sealing ring 105 is inserted into the protruding sealing groove. The pressure plate 104 is tightened with screws to compress the rod sealing ring 105, completing the sealing of the main gear rod 9. This design ensures that the system maintains good sealing during the pitching operation, preventing sewage leakage or external impurities from entering.

[0046] The upper end of the main gear rod 9 is a hexagonal rod, which facilitates the engagement with the handwheel 14. The hexagonal rod is threaded at the top. The handwheel 14 is inserted into the hexagonal rod and then screwed in place with a nut 103. The outer gear of the main gear rod 9 meshes with the inner gear of the ball tray 12. The secondary gear rod 11 fits into the pre-set rings of the top cover 1 and the pitching cover 10, achieving vertical fixation and allowing rotation. Its outer gear also meshes with the inner gear of the ball tray 12. This gear transmission design ensures precise control of the pitching operation, allowing only a ball 13 of a specific diameter to be dropped at a time.

[0047] The (N+1)th ball slot in the ball tray 12 is empty, and the balls 13 in the slots are arranged in a circular pattern of increasing diameters. When the handwheel 14 is rotated, it drives the ball tray 12 via the main gear rod 9. Each rotation of the handwheel 14 results in the tray 12 rotating one slot, and the balls 13 in the slots fall through the outlet of the ball dropper 10 into the tank 4. This design ensures controllable and accurate ball dropping, preventing filtration system failure caused by misoperation.

[0048] The diameter of the adapting ball 13 is larger than the inner hole size of the ball seat 802 of this level (105mm-5mm), and smaller than the inner hole size of the ball seat 802 of the previous level (105mm-5mm). In this embodiment, from bottom to top, the inner hole diameter of the first-level ball seat 802 is 25mm, and the diameter of the first-level adapting ball 13 is 27mm; the inner hole diameter of the second-level ball seat 802 is 30mm, and the diameter of the second-level adapting ball 13 is 32mm; the inner hole diameter of the third-level ball seat 802 is 35mm, and the diameter of the third-level adapting ball 13 is 37mm; the inner hole diameter of the fourth-level ball seat 802 is 40mm, and the diameter of the fourth-level adapting ball 13 is 42mm; the inner hole diameter of the fifth-level ball seat 802 is 45mm, and the diameter of the fifth-level adapting ball 13 is 47mm. This size design ensures that the ball 13 can be accurately snapped into the ball seat 802 of the corresponding level, triggering the corresponding unlocking mechanism.

[0049] When the ball throwing mechanism throws the ball 13 into the corresponding ball seat 802, the ball seat 802 is pressed down, driving the retaining spring 805 to hook the slide 804 and move downward, and the supporting ball 806 is disengaged, completing the separation of the sleeve 807 from the upper level locking ball sleeve 801, completing the unlocking and opening the next level filter unit, forming a step-by-step relay mechanism for sewage filtration, and giving full play to the filtering efficiency of each level of filter cloth 16.

[0050] The device operates as follows: First, install the device at the wellhead, ensure the sealed tank is securely connected to the wellhead, and check the installation status of all components. Then, by rotating the handwheel 14, the first ball 13 with the smallest diameter is dropped into the tank 4. This ball 13 falls into the first-stage ball seat 802. Because its diameter is larger than the inner hole of the seat 802, the ball 13 becomes stuck in the seat 802 and exerts downward pressure on the seat 802.

[0051] Under pressure, pin 803 shears, causing ball seat 802 to move downward, driving the attached retaining spring 805 and slide 804 downward. When ball seat 802 reaches a certain position, support ball 806 loses its support and moves toward the center of slide 804, disengaging the steel ball groove of the previous locking ball sleeve 801 and unlocking the first-stage filter unit. At this point, the wastewater begins to be filtered through the newly deployed filter cloth 16, trapping impurities on the filter cloth 16.

[0052] After a period of filtration, filter cloth 16 may trap impurities, causing filtration efficiency to decline. At this point, the operator can rotate handwheel 14 to insert a second ball 13. This second ball 13 will fall into the second-stage ball seat 802, triggering a similar unlocking mechanism to activate the second-stage filter unit. This cycle continues until all five filter units are activated, achieving progressively finer filtration of the wastewater.

[0053] This step-by-step filtration design effectively extends the service life of the filtration system and avoids the rapid clogging problem caused by single-stage filtration. At the same time, by controlling the time interval between ball injections, the filtration strategy can be flexibly adjusted according to the actual sewage situation, improving the adaptability and efficiency of the system.

[0054] Example

[0055] Based on the first embodiment, the number N of progressive sliding sleeve groups 8 in this embodiment is set to 3, that is, three stages of progressive sliding sleeve groups 8 are provided. Accordingly, the outer ring of the ball tray 12 in the ball pitching mechanism is provided with four cylindrical ball grooves, three of which are used to accommodate balls 13 of gradually increasing diameters, and the fourth ball groove is empty.

[0056] From bottom to top, the first-stage ball seat 802 has an inner diameter of 40mm, and the first-stage adapting ball 13 has a diameter of 44mm; the second-stage ball seat 802 has an inner diameter of 48mm, and the second-stage adapting ball 13 has a diameter of 52mm; the third-stage ball seat 802 has an inner diameter of 56mm, and the third-stage adapting ball 13 has a diameter of 60mm. This design is suitable for applications with low pollution levels or low requirements for filtration accuracy, and it provides a simpler structure and more convenient operation.

[0057] Example

[0058] Based on the first embodiment, the number N of step-by-step sliding sleeve groups 8 in this embodiment is set to 8, that is, 8 steps of step-by-step sliding sleeve groups 8 are provided. Accordingly, the outer ring of the ball tray 12 in the ball pitching mechanism is provided with 9 cylindrical ball grooves, 8 of which are used to accommodate balls 13 of gradually increasing diameters, and the 9th ball groove is empty.

[0059] From bottom to top, the inner hole diameter of the first-level ball seat 802 is 30mm, and the diameter of the first-level adaptive ball 13 is 33mm; the inner hole diameter of the second-level ball seat 802 is 36mm, and the diameter of the second-level adaptive ball 13 is 39mm; the inner hole diameter of the third-level ball seat 802 is 42mm, and the diameter of the third-level adaptive ball 13 is 45mm; the inner hole diameter of the fourth-level ball seat 802 is 48mm, and the diameter of the fourth-level adaptive ball 13 is 51mm; the inner hole diameter of the fifth-level ball seat 802 is 54mm, and the diameter of the fifth-level adaptive ball 13 is 57mm; the inner hole diameter of the sixth-level ball seat 802 is 60mm, and the diameter of the sixth-level adaptive ball 13 is 63mm; the inner hole diameter of the seventh-level ball seat 802 is 66mm, and the diameter of the seventh-level adaptive ball 13 is 69mm; the inner hole diameter of the eighth-level ball seat 802 is 72mm, and the diameter of the eighth-level adaptive ball 13 is 75mm.

[0060] This multi-stage filtration design is suitable for situations with high pollution levels or strict requirements on filtration accuracy. It can achieve more refined graded filtration, improve filtration effects and system service life.

[0061] Example

[0062] Building on the first embodiment, this embodiment utilizes a stainless steel wire rope for the pulling wire 15, with a diameter of 2 mm and a length that is 85% of the extended length of the filter cloth 16. This design allows the filter cloth 16 to form a suitable arc during filtration, increasing the effective filtration area and improving filtration efficiency. Furthermore, the stainless steel wire rope exhibits excellent corrosion resistance and mechanical strength, ensuring long-term use in harsh environments.

[0063] Example

[0064] Building on the first embodiment, the handwheel 14 of the ball-dropping mechanism in this embodiment features a graduated scale. Each rotation corresponds to one ball slot in the ball-dropping disc 12. A locking reminder mechanism is incorporated into the outer ring of handwheel 14. When the handwheel 14 rotates one full rotation, a raised point on the handwheel 14 contacts a spring, emitting a warning sound. This prevents premature delivery of the ball 13 due to misoperation. This design improves operational accuracy and safety, preventing filtration system malfunctions caused by operational errors.

[0065] It should be noted that the first embodiment, the second embodiment, the third embodiment, the fourth embodiment, and the fifth embodiment are all a type of step-by-step wellhead fine filtering device.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A step-by-step wellhead fine filtration device, characterized in that: It includes a sealed tank body, a step-by-step series filtering structure and a ball pitching mechanism; The step-by-step series filtering structure comprises an upper support plate (5), wherein the lower outer ring of the upper support plate (5) presses the support filter cartridge (6), and the support ball (806) is locked through the central hole steel ball groove and the steel ball grooves of N step-by-step sliding sleeve groups (8) to achieve N The stages are connected in series, and the bottom step-by-step sliding sleeve group (8) is connected to the bottom plate (7) through the pulling wire (15) and the filter cloth (16). The inner hole of the ball seat (802) of each step-by-step sliding sleeve group (8) increases in diameter from bottom to top, and is adapted to the round ball (13) with increasing diameter in the pitching mechanism. When the pitching mechanism throws the round ball (13) into the corresponding ball seat (802), the ball seat (802) is pressed down, driving the retaining spring (805) to hook the slide cylinder (804) and move it down, and the support ball (806) is separated, completing the separation of the sleeve (807) and the locking ball sleeve (801) of the upper stage, completing the unlocking and opening the next stage filter unit, forming a step-by-step relay mechanism for sewage filtration, and the slide cylinder (804) after moving down is seated in the locking ball sleeve (801) of this stage, keeping the height of the step-by-step sliding sleeve group (8) unchanged after falling, ensuring that each stage of filter cloth (16) can fully carry out filtration.

2. A step-by-step wellhead fine filtration device according to claim 1, characterized in that: Each level of the step-by-step sliding sleeve group (8) includes a sleeve (807), the sleeve (807) is threaded at the center lower end thereof to connect the locking ball sleeve (801), the locking ball sleeve (801) is designed with a steel ball groove, and a sealing groove is turned out from the inside and outside of the tube, an O-ring is inserted into the sealing groove, the sleeve (807) center hole is placed on the slide (804), the protruding ring at the bottom of the slide (804) can hold the sleeve (807), a plurality of oblique circular holes are drilled on the upper part of the slide (804) and a supporting ball (806) is placed therein, and the slide (807) is provided with a plurality of oblique circular holes. 04) is inserted into the ball seat (802) and a pin (803) is inserted into the bottom of the ball seat (802) to lock the two parts. The inserted ball seat (802) blocks the support ball (806) from moving toward the central axis of the slide cylinder (804), so that a part of the support ball (806) is stuck in the oblique circular hole of the slide cylinder (804), and the other part is stuck in the ball locking sleeve (801) steel ball groove of the step-by-step sliding sleeve group (8) above, thereby realizing the step-by-step series filtering and locking between the step-by-step sliding sleeve groups (8) at each level.

3. The step-by-step wellhead fine filtration device according to claim 1, characterized in that: The ball pitching mechanism comprises a top cover (1), the top cover (1) is provided with a ball pitching observation structure and a ball pitching transmission assembly, a ball pitching cover (10) is fixed upside down on the bottom of the top cover (1) and is locked with screws on the outer ring, a main gear rod (9), a sub-gear rod (11) and a ball set disc (12) are meshed with each other, and N+1 cylindrical ball grooves on the outer ring of the ball set disc (12) are provided with balls (13) with gradually increasing diameters in the N ball grooves, and a hand wheel (14) is rotated to drive the ball set disc (12) to rotate, so that the balls (13) fall into the tank body (4) through the outlet of the ball pitching cover (10).

4. The step-by-step wellhead fine filtration device according to claim 1, characterized in that: The number of the step-by-step sliding sleeve groups (8) is N, and N is an integer of 2-10.

5. The step-by-step wellhead fine filtration device according to claim 1, characterized in that: The filter cloth (16) is a flexible filter material, and has a pressure ring on the upper and lower parts thereof, forming a disposable detachable accessory. After the screw is passed through the reserved circular hole of the pressure ring of the filter cloth (16), it is locked with the upper support plate (5), the sleeve plate (807) and the bottom plate (7), thereby connecting N+1 filter cloths (16) in annular segments.

6. The step-by-step wellhead fine filtration device according to claim 3, characterized in that: The N+1th ball slot of the ball tray (12) is an empty slot, and the balls (13) in the ball slots are arranged circumferentially in increasing order according to their diameters. When the hand wheel (14) is rotated, the hand wheel (14) drives the ball tray (12) to rotate via the main gear rod (9). When the hand wheel (14) rotates one circle, the ball tray (12) rotates one ball slot, and the balls (13) in the ball slots fall into the interior of the tank body (4) through the outlet of the ball throwing cover (10).

7. The step-by-step wellhead fine filtration device according to claim 1, characterized in that: The diameter of the adapted ball (13) is larger than the inner hole size of the ball seat (802) of the current level (105mm-5mm), and smaller than the inner hole size of the ball seat (802) of the upper level (105mm-5mm).

8. The step-by-step wellhead fine filtration device according to claim 1, characterized in that: The length of the pulling wire (15) is 80%-95% of the unfolded length of the filter cloth (16).

9. The step-by-step wellhead fine filtration device according to claim 1, characterized in that: The sealed tank body comprises a tank body (4), a top cover (1) is placed on the tank body (4) to form a closed filtering space, a sealing rubber pad (3) is arranged between the top cover (1) and the tank body (4), and a plurality of quick-install bolts (2) are arranged on the outer ring of the top of the tank body (4). Tightening the quick-install bolts (2) can compress the sealing rubber pad (3), thereby completing the closure and sealing of the device.

10. The step-by-step wellhead fine filtration device according to claim 3, characterized in that: The bottom of the main gear rod (9) is inserted into the preset circular hole groove of the pitching cover (10) to achieve bottom fixation, and the upper part thereof passes through the top cover (1). A protruding sealing groove is provided on the top cover (1), and the rod sealing ring (105) is inserted into the protruding sealing groove. The pressure plate (104) is tightened with a screw to compress the rod sealing ring (105), thereby completing the sealing of the main gear rod (9).

11. The step-by-step wellhead fine filtration device according to claim 3, characterized in that: The upper end of the main gear rod (9) is a hexagonal rod, which is convenient for matching with the hand wheel (14). The top end of the hexagonal rod is a threaded rod. After the hand wheel (14) is inserted into the hexagonal rod, it is fixed by thread locking with a nut (103). The outer gear of the main gear rod (9) and the inner gear of the ball disc (12) are meshed with each other. The auxiliary gear rod (11) is inserted into the preset ring sleeve of the top cover (1) and the pitching cover (10) to achieve upper and lower fixation and rotation. Its outer gear is also meshed with the inner gear of the ball disc (12).

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