Valve box and suction cylinder of fracturing pump

Abstract

The invention provides a fracturing pump valve box and a suction cylinder, the suction cylinder comprises a suction cavity, the suction cavity is communicated with a liquid inlet channel, a valve seat and a suction valve body are arranged at the communication position of the liquid inlet channel and the suction cavity, and the fracturing pump valve box further comprises a centralizing frame mounting groove which is an annular groove and is formed in the inner wall of the suction cavity; the left side and the right side of the centralizing frame are each provided with a positioning part, the bottom of the centralizing frame abuts against one end of an elastic piece, the positioning parts are installed in the centralizing frame installation groove in a deflectable clamping mode, and the other end of the elastic piece abuts against the suction valve body; the end plug mounting cavity is arranged on one side of the suction cavity, and the front end of the end plug mounting cavity extends into the suction cavity; the end plug is installed in the end plug installation cavity in a sealed mode, and a gear part is arranged at the front end of the end plug. The method has the beneficial effects that the adverse effect of stress concentration at the bottom of the eccentric groove on the valve box can be eliminated, the situation that the valve box is frequently scrapped after being used for a short time and the service life is greatly shortened in the ultrahigh-pressure working condition is avoided, and the average service life of the valve box is restored to 600 h or above.

Description

Technical Field

[0001] This invention relates to the field of pumping, and more specifically, to a fracturing pump valve box and suction cylinder. Background Technology

[0002] Pump and valve boxes are important components in ultra-high pressure pumping equipment, and are commonly used in fields such as petrochemicals and oil and gas well enhancement that require large displacement and high pump pressure.

[0003] Deep shale gas development often employs large-scale, factory-style fracturing operations. These operations involve large displacements, typically around 20m³. 3 The pumping speed is approximately [missing information] / min; the injection pressure is high, around 110 MPa, with a maximum of over 120 MPa; the construction time is long, with each section continuously pumping for about 3.5 hours, generally 2-3 sections are constructed per day, and each fracturing machine pumps for about 9 hours per day. Under these harsh conditions, the average service life of the fracturing pump valve box has decreased from over 600 hours to an average of only 237.5 hours, with the shortest being only 9.9 hours. This leads to a significant increase in valve box purchase costs, frequent replacement of worn-out valve boxes, and isted time that could be used for fracturing operations, reducing operational efficiency and increasing the labor intensity of equipment operators as well as the resulting safety risks.

[0004] In conventional fracturing operations, stainless steel valve boxes with an average service life of over 600 hours experience a fracturing fluid leak on average only 237.5 hours in ultra-high pressure fracturing operations, rendering them unusable. Cross-sectional inspection of the damaged valve boxes revealed that the root cause of the damage was the eccentric groove inside the valve box used for positioning the valve body spring stabilizer. Under ultra-high pressure of approximately 110 MPa, stress concentrated at the bottom of this groove, causing cracks to appear after a short period of use. These cracks extended and connected with the valve box fixing bolt holes, leading to fracturing fluid leaks. Furthermore, the fracturing fluid, after communicating with the bolt holes through the cracks, entered the main pump's power unit, contaminating the lubricating oil and damaging critical components such as the crankshaft and connecting rods. Summary of the Invention

[0005] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide a fracturing pump valve box and suction cylinder. By optimizing the internal component structure of the valve box, redesigning the positioning method of the centralizing frame, and eliminating the eccentric groove structure inside the valve box, the stress concentration phenomenon at the bottom of the eccentric groove is eliminated, thus preventing stress concentration from causing cracks in the valve box and effectively extending the service life of the valve box.

[0006] To achieve the above objectives, this invention provides a fracturing pump valve box suction cylinder, including a suction chamber, a liquid inlet channel connected to the suction chamber, a valve seat fixed at the connection between the liquid inlet channel and the suction chamber, and a suction valve body that cooperates with the valve seat to open and close the liquid inlet channel. It also includes: a centralizing frame mounting groove, which is an annular groove and is disposed on the inner wall of the suction chamber; a centralizing frame, each side having a positioning part, the bottom of which abuts against one end of an elastic element, the positioning part being rotatably locked in the centralizing frame mounting groove, the other end of the elastic element abutting against the suction valve body to provide a restoring elastic force to the suction valve body during the closure of the liquid inlet channel; an end plug mounting cavity, disposed on one side of the suction chamber, with its front end extending into the suction chamber; and an end plug, sealed and installed in the end plug mounting cavity, with a stop part at its front end. After installation, the stop part extends into the suction chamber to limit the maximum deflection angle of the centralizing frame when it deflects, through the abutment between the stop part and the positioning part. Therefore, this solution eliminates the need for an eccentric groove and a positioning pin.

[0007] In a preferred embodiment of this solution, the positioning part is a plate structure that is provided on both sides of the top of the straightening frame and extends outward and upward; the end of the plate structure is provided with a hanging plate part, which is snapped into the mounting groove of the straightening frame to realize the deflectable installation of the straightening frame.

[0008] In a preferred embodiment of this solution, the plate structure is a fan-shaped plate, and the hanging plate part is an arc-shaped protrusion horizontally arranged on the edge of the fan-shaped plate. The fan-shaped plate design helps to improve stability.

[0009] In a preferred embodiment of this solution, a shock-absorbing sleeve is also fitted onto the outside of the mounting plate.

[0010] In a preferred embodiment of this solution, the stop portion is a cylindrical skirt structure located at the front of the end plug; the cylindrical skirt structure has multiple circular through holes evenly distributed along its circumference. The design of the cylindrical skirt structure avoids the problem of significantly reducing the internal space of the pump body due to the installation of the stop portion. The multiple circular through holes facilitate liquid flow during pumping.

[0011] In a preferred embodiment of this solution, the end plug has a Y-shaped packing groove circumferentially formed on its outer peripheral surface, and a Y-shaped packing is provided in the Y-shaped packing groove; the end plug and the stop part are integrated into one design, and the length of the overall structure formed by the end plug and the stop part is 82-93.5mm; the distance between the Y-shaped packing groove and the outer end face of the end plug is 41mm-45.5mm.

[0012] In a preferred embodiment of this solution, the fracturing pump valve box further includes an end plug cap, which is installed outside the end plug mounting cavity and presses tightly against the end plug. This helps ensure stable installation of the end plug and guarantees the safety and reliability of high-pressure fluid transmission within the sealed pump chamber.

[0013] In a preferred embodiment of this solution, the end plug mounting cavity is perpendicular to the suction cavity.

[0014] In a preferred embodiment of this solution, the suction chamber is connected to a plunger chamber, and a plunger is provided in the plunger chamber. The plunger reciprocates within the plunger chamber to create positive and negative pressures within the suction chamber, thereby driving the valve body to open and close.

[0015] On the other hand, the present invention also provides a fracturing pump valve box, including a plunger chamber, a discharge cylinder, and the aforementioned fracturing pump valve box suction cylinder; the plunger chamber, the discharge cylinder, and the suction cylinder are interconnected; the plunger chamber is provided with a plunger that can reciprocate back and forth, and when the plunger moves backward, the suction valve body moves upward against the pressure of the elastic element to open the liquid inlet channel; when the plunger moves forward, the suction valve body moves downward under the pressure of the elastic element to close the liquid inlet channel; the discharge chamber is provided with a discharge channel, and a discharge valve body and a discharge valve seat for opening and closing the discharge channel.

[0016] In a preferred embodiment of this solution, the end plug mounting cavity and the plunger cavity are arranged opposite to each other and are located on both sides of the suction cavity; when the end plug is installed, the maximum deflection angle of the straightening frame is α; when the end plug is not installed and the plunger moves forward to the farthest end to form a stop on the straightening frame, the maximum deflection angle of the straightening frame is β; α is less than β.

[0017] In a preferred embodiment of this solution, α is 24° to 35° and β is 37°.

[0018] In a preferred embodiment of this solution, the center of the straightening frame is coaxially provided with a guide center hole; below the valve seat, a support tray is provided at the connection between the liquid inlet channel and the suction chamber, and a vertical through-hole is opened in the center of the support tray; the suction valve body is provided with an upper guide rod and a lower guide rod at the center of its top and bottom, respectively.

[0019] After installation, the upper guide rod extends into the guide center hole, and the lower guide rod extends into the through hole to guide the suction valve body during its up-and-down movement.

[0020] In a preferred embodiment of this solution, the elastic element is a spring; a spring positioning cylinder is provided at the bottom of the straightening frame, and a guide center hole passes through the spring positioning cylinder downward; a foot is also provided on each side of the spring positioning cylinder at the bottom of the straightening frame, so that the spring can be positioned by the spring positioning cylinder and the two feet; after installation, the top of the spring is fitted outside the spring positioning cylinder and abuts against the lower surface of the straightening frame, and the bottom of the spring is fitted outside the upper guide rod and abuts against the upper surface of the suction valve body.

[0021] In a preferred embodiment of this solution, the diameter of the lower guide rod is smaller than the diameter of the through-hole, and the suction chamber is connected to the liquid inlet channel through the through-hole.

[0022] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0023] (1) This invention proposes a fracturing pump valve box, which is designed with a stop part at the front end of the end plug and extends into the suction chamber to form a stop for the centralizing frame installed in the suction chamber, thereby limiting the maximum deflection angle of the centralizing frame; thus, there is no need to set a positioning pin on the centralizing frame, nor is there a need to open an eccentric groove inside the valve box. In this way, this solution can eliminate the adverse effects of stress concentration at the bottom of the eccentric groove on the valve box, avoid the valve box from being frequently scrapped after short-term use in ultra-high pressure conditions, and significantly shorten its service life, and restore the average service life of the valve box to more than 600 hours; and reduce the manpower and material consumption increased by frequent replacement of the valve box, reduce the safety risk of replacing the valve box; and prevent fracturing fluid from entering the lubricating oil of the large pump, causing the lubricating oil to emulsify and become scrapped.

[0024] (2) The straightening frame in the mounting groove deflects under the disturbance of liquid flow. The end block of its stop part limits the extreme deflection angle of the straightening frame to 28°, which is much smaller than the 37° when the plunger and the straightening frame rub against each other. When the straightening frame deflects to its extreme, it contacts the end block stop part, which can ensure reliable positioning of the spring and does not interfere with the reciprocating motion of the plunger. The structure is compact and the layout is reasonable.

[0025] (3) The stop section is a cylindrical skirt structure set at the front end of the end plug. The design of the cylindrical skirt structure will not excessively affect the internal space volume of the pump chamber. In addition, multiple circular through holes are evenly distributed on the cylindrical skirt structure. With this design, the reduction of the cross-sectional area of ​​the fracturing fluid can still meet the requirements of the valve box for the flow area of ​​the valve box cavity when the maximum pumping discharge is reached. Attached Figure Description

[0026] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0027] Figure 1 A cross-sectional view of a fracturing pump valve box in an exemplary embodiment of the present invention, showing the uprighting frame and end plug in abutment, is shown.

[0028] Figure 2 A cross-sectional view of a fracturing pump valve box, an exemplary embodiment of the present invention, is shown.

[0029] Figure 3 A schematic diagram of a centralizing frame structure for a fracturing pump valve box, according to an exemplary embodiment of the present invention, is shown.

[0030] Figure 4 A schematic diagram of an end plug structure for a fracturing pump valve box according to an exemplary embodiment of the present invention is shown.

[0031] Figure 5A cross-sectional view of an existing fracturing pump valve box structure is shown.

[0032] Figure 6 A schematic diagram of the existing fracturing pump valve box structure is shown, illustrating the engagement of the eccentric groove with the spring-loaded centralizing pin.

[0033] Figure 7 A schematic diagram of the straightening frame structure of an existing fracturing pump valve box is shown.

[0034] Figure 8 A schematic diagram of the end plug structure of an existing fracturing pump valve box is shown.

[0035] Figure 9 A perspective view of a centralizing frame for a fracturing pump valve box, according to an exemplary embodiment of the present invention, is shown.

[0036] Figure 10 The diagram shows an enlarged view of the uprighting bracket portion of a fracturing pump valve box according to an exemplary embodiment of the present invention.

[0037] Explanation of key figure labels:

[0038] 1. Plunger; 2. Straightening frame mounting slot; 3. Straightening frame; 4. Elastic element; 5. Suction valve body; 6. Valve seat; 7. Support plate; 8. Stop part; 9. End plug; 10. End plug cap; 11. Suction chamber; 12. Liquid inlet channel; 301. Positioning part; 302. Guide center hole; 303. Spring positioning cylinder; 304. Support leg; 305. Shock absorber sleeve; 501. Upper guide rod; 502. Lower guide rod; 901. Y-type packing groove; 3011. Hanging plate part. Detailed Implementation

[0039] In the following description, a fracturing pump valve box and suction cylinder of the present invention will be explained in detail with reference to exemplary embodiments.

[0040] It should be noted that terms such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," and "bottom" are used only to facilitate the description and formation of relative orientations or positional relationships, and do not indicate or imply that the component referred to must have that specific orientation or position.

[0041] It should be noted that the "maximum deflection angle" mentioned in this invention refers to the maximum angle value that can be achieved when the straightening frame deflects in one direction.

[0042] refer to Figures 5-8 As shown, the traditional straightening frame is installed in the straightening frame mounting groove. To prevent the straightening frame from deflecting under the disturbance of liquid flow, there is a locking pin groove b on the inner wall of the original valve box (see locking pin groove b). Figure 5 , Figure 6The red area in the diagram, along with the centering pin a, positions the centering frame. During ultra-high pressure pumping operations, stress concentration in the centering pin groove b leads to cracks at the bottom of the eccentric groove after a short period of use, resulting in the valve box becoming unusable. Therefore, this invention optimizes the internal component structure of the fracturing pump valve box and redesigns the centering frame positioning method to effectively extend the valve box's service life.

[0043] Figure 1 A cross-sectional view of a fracturing pump valve box in an exemplary embodiment of the present invention, showing the uprighting frame and end plug in abutment, is shown. Figure 2 A cross-sectional view of a fracturing pump valve box, an exemplary embodiment of the present invention, is shown. Figure 3 A schematic diagram of a centralizing frame structure for a fracturing pump valve box, according to an exemplary embodiment of the present invention, is shown. Figure 4 A schematic diagram of an end plug structure for a fracturing pump valve box according to an exemplary embodiment of the present invention is shown.

[0044] Exemplary Example 1

[0045] like Figures 1-4 As shown, a fracturing pump valve box suction cylinder includes a suction chamber 11 and an end plug mounting cavity. The bottom of the suction chamber 11 is connected to a liquid inlet channel 12. A valve seat 6 and a suction valve body 5 are provided at the connection between the suction chamber 11 and the liquid inlet channel 12. The suction valve body 5 cooperates with the valve seat 6 to control the opening and closing of the liquid inlet channel 12. The suction chamber 11 is also provided with a straightening frame mounting groove 2 and a straightening frame 3. An end plug 9 is sealed and installed inside the end plug mounting cavity.

[0046] The straightening frame mounting groove 2 is an annular groove set on the inner wall of the suction chamber 11; a positioning part 301 is provided on each side of the straightening frame 3, and the straightening frame 3 is rotatably locked in the straightening frame mounting groove 2 through the positioning part 301; the end plug 9 has an integrated stop part 8 at the front end, which extends into the suction chamber 11. When the straightening frame 3 deflects at a certain angle, the stop part 8 can abut against the positioning part 301 to limit the maximum deflection angle of the straightening frame 3; thus, this exemplary embodiment does not require a positioning pin on the straightening frame, nor does it require an eccentric groove to be opened inside the valve box. Therefore, this exemplary embodiment can eliminate the stress concentration phenomenon at the bottom of the eccentric groove, avoid stress concentration leading to valve box cracks, and effectively extend the service life of the valve box.

[0047] Furthermore, in this exemplary embodiment, the bottom of the straightening frame 3 abuts against an elastic element 4, which is a spring. The bottom end of the spring abuts against the suction valve body 5, thereby providing a restoring force to the suction valve body 5 through the elastic element 4 during the process of closing the liquid inlet channel.

[0048] In this exemplary embodiment, the positioning part 301 is a plate structure provided on both sides of the top of the straightening frame 3 and extending outward and upward. The plate structure is slightly fan-shaped, which increases the contact surface with the mounting groove 2 of the straightening frame, thereby improving stability.

[0049] refer to Figure 1 , Figure 2 , Figure 9 ,as well as Figure 10 As shown in this exemplary embodiment, a hanging plate portion 3011 is provided horizontally at the end of the plate structure. The hanging plate portion 3011 is an arc-shaped protrusion. The straightening frame 3 is clamped in the straightening frame mounting groove 2 through the arc-shaped protrusion to realize the deflectable installation of the straightening frame 3.

[0050] Furthermore, in this exemplary embodiment, a shock-absorbing sleeve 305 is also fitted on the outside of the mounting plate portion 3011, and the shock-absorbing sleeve 305 is a rubber shock-absorbing sleeve.

[0051] To prevent the stop portion 8 extending into the suction cavity 11 from affecting the internal volume of the suction cavity 11, in this exemplary embodiment, the stop portion 8 is a cylindrical skirt structure provided at the front of the end plug 9; and a plurality of circular through holes are uniformly opened along the circumference of its skirt surface.

[0052] In this exemplary embodiment, the end plug mounting cavity is perpendicular to the suction cavity 11. During the pumping operation, the end plug 9 is used to seal the end plug mounting cavity. After the operation is completed, the end plug 9 is removed, and the internal components of the valve box can be inspected and maintained through the end plug mounting cavity.

[0053] To be more specific, refer to Figure 8 As shown, the thickness of the original end plug is 60 mm. In this exemplary embodiment, the newly designed end plug 9 extends a hollow skirt (cylindrical skirt structure) towards the pump cavity side based on the original end plug thickness of 60 mm; the total length of the rear end plug 9 is optimized to 82-93.5 mm, the outer diameter of the skirt is 112.6 mm, the inner diameter is 105-106 mm, and within a range of 10-17 mm from the bottom of the skirt, 12 circular through holes with a diameter of 10-16 mm are evenly distributed radially at 30° intervals along the circumference of the skirt surface. The Y-type packing has a width of 10.3±0.1mm and a depth of 5.8mm. To ensure good support of the Y-type packing in the Y-type packing groove 901 for the horizontal end plug 9 and reliable sealing of the surrounding small annular space, the Y-type packing groove 901 is moved 9mm to 13.5mm towards the skirt direction relative to the original design position. That is, in this exemplary embodiment, the outer wall of the Y-type packing groove 901 is 41mm to 45.5mm away from the outer side of the end plug 9 (with the skirt end of the end plug as the inner end).

[0054] Exemplary Example 2

[0055] A fracturing pump valve box includes a plunger chamber, a discharge cylinder, and an intake cylinder as described in the exemplary embodiment above.

[0056] The discharge cylinder includes a discharge chamber with a discharge channel, and a discharge valve body and a discharge valve seat for controlling the opening and closing of the discharge channel (the discharge chamber, discharge valve body, and discharge valve seat are common structures in existing fracturing pump boxes and will not be elaborated in detail in this exemplary embodiment); the suction chamber and discharge chamber constitute the main body of the pump chamber, and a plunger 1 is provided in the plunger chamber; Reference Figure 1 and Figure 2 As shown, the plunger 1 moves backward to draw in fluid, creating a negative pressure inside the valve box. Under this negative pressure, the suction valve body 5 overcomes the spring pressure and moves upward to open the inlet channel 12, filling the pump chamber with fracturing fluid. When the plunger 1 moves forward, it pumps the fluid, and the suction valve body 5 moves downward under the spring pressure, contacting the valve seat 6 to close the inlet channel. The plunger 1 reciprocates, realizing the suction and pumping of fracturing fluid.

[0057] Furthermore, in this exemplary embodiment, the suction valve body 5 is provided with an upper guide rod 501 and a lower guide rod 502. The upper guide rod 501 is positioned by the guide center hole 302 of the straightening frame 3, and the lower guide rod 502 is positioned by the through hole of the support tray 7. The diameter of the lower guide rod 502 is smaller than the diameter of the through hole, and the suction chamber 11 is connected to the liquid inlet channel 12 through the through hole.

[0058] In this exemplary embodiment, the end plug mounting cavity and the plunger cavity are arranged opposite to each other and are located on both sides of the suction cavity 11, and are perpendicular to the suction cavity 11; when the end plug 9 is installed, the maximum deflection angle of the straightening frame 3 is α; when the end plug 9 is not installed and the plunger 1 moves forward to the farthest end to form a stop on the straightening frame 3, the maximum deflection angle of the straightening frame 3 is β; in order to avoid the plunger 1 colliding with the straightening frame 3, α must be less than β.

[0059] In this exemplary embodiment, the preferred α is 28° and β is 37°; the straightening frame 3 in the straightening frame mounting groove 2 deflects under the disturbance of liquid flow, and the deflection angle is less than 37°, so the straightening frame 3 will not rub or collide with the plunger 1.

[0060] In this exemplary embodiment, the skirt end face of the newly designed end plug 9 limits the extreme deflection angle of the straightening frame 3 to 28°, which is much smaller than the 37° at which the plunger 1 and the straightening frame 3 rub against each other. When the straightening frame 3 deflects to its extreme, it contacts the skirt of the end plug 9, which can ensure reliable positioning of the spring and does not interfere with the reciprocating motion of the plunger 1.

[0061] refer to Figure 1 , Figure 9 , Figure 10 As shown in this exemplary embodiment, the front end of the plunger cavity extends into the suction cavity 11; thereby, the straightening frame mounting groove 2 forms a notch at the connection between the plunger cavity and the suction cavity 11, and at the connection between the end plug mounting cavity and the suction cavity 11; the hanging plate part 3011 can be inserted into the straightening frame mounting groove 2 through the notch.

[0062] For details, please refer to Figures 1-3 As shown, when installing the straightening frame 3, first place the straightening frame 3 vertically into the suction chamber 11, aligning the positioning part 301 with the two notches of the straightening frame mounting groove 2. Then, use a tool to press the straightening frame 3 downwards, so that the two hanging plate parts 3011 and the annular straightening frame mounting groove 2 are at the same height. Then, rotate it 90° so that the hanging plate parts 3011 enter the straightening frame mounting groove 2, completing the installation of the straightening frame 3. It should be noted that when installing the straightening frame 3, the plunger 1 must be retracted to the rear of the straightening frame mounting groove 2.

[0063] Further, refer to Figure 2 , Figure 9 As shown in this exemplary embodiment, the bottom of the straightening frame 3 is provided with a spring positioning cylinder 303, and the guide center hole 302 passes downward through the spring positioning cylinder 303; each side of the spring positioning cylinder 303 is also provided with a foot 304. The top of the spring is positioned via the spring positioning cylinder 303 and the two feet 304. After installation, the top of the spring is fitted onto the outside of the spring positioning cylinder 303 and abuts against the lower surface of the straightening frame 3, and the bottom of the spring is fitted onto the outside of the upper guide rod 501 and abuts against the upper surface of the suction valve body 5. In addition, the feet 304 have a sufficiently small volume and will not affect the upward pumping of fluid.

[0064] refer to Figure 1 As shown, the fracturing pump valve box also includes an end plug cap 10, which is installed outside the end plug mounting cavity and presses tightly against the end plug 9. This helps to ensure the stable installation of the end plug 9 and ensures the safety and reliability of high-pressure fluid transmission within the sealed pump cavity.

[0065] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A fracturing pump valve box suction cylinder, comprising a suction chamber (11), the suction chamber (11) being connected to a liquid inlet channel (12), a valve seat (6) fixedly disposed at the connection between the liquid inlet channel (12) and the suction chamber (11), and a suction valve body (5) cooperating with the valve seat (6) to realize the opening and closing of the liquid inlet channel (12), characterized in that, Also includes: The straightening frame mounting groove (2) is an annular groove and is located on the inner wall of the suction chamber (11); The straightening frame (3) has a positioning part (301) on each of its left and right sides. The bottom of the positioning part (301) abuts against one end of the elastic element (4). The positioning part (301) is rotatably installed in the mounting groove (2) of the straightening frame. The other end of the elastic element (4) abuts against the suction valve body (5) to provide a reset elastic force for the suction valve body (5) during the process of closing the liquid inlet channel. The end plug installation cavity is located on one side of the suction cavity (11), and its front end extends into the suction cavity (11); The end plug (9) is sealed in the end plug installation cavity and has a stop part (8) at its front end. After installation, the stop part (8) extends into the suction cavity (11) so that when the straightening frame (3) deflects, the stop part (8) and the positioning part (301) abut against each other to limit the maximum deflection angle of the straightening frame (3).

2. The fracturing pump valve box suction cylinder according to claim 1, characterized in that: The positioning part (301) is a plate structure that is provided on both sides of the top of the straightening frame (3) and extends outward and upward; The plate structure is provided with a hanging plate part (3011) at the end. The hanging plate part (3011) is installed in the mounting groove (2) of the straightening frame to realize the deflectable installation of the straightening frame (3).

3. The fracturing pump valve box suction cylinder according to claim 2, characterized in that: The plate structure is a fan-shaped plate, and the hanging plate part (3011) is an arc-shaped protrusion horizontally set on the edge of the fan-shaped plate.

4. The fracturing pump valve box suction cylinder according to claim 1, characterized in that: The stop part (8) is a tubular skirt structure provided in front of the end plug (9); The tubular skirt structure has multiple circular through holes evenly distributed around its circumference.

5. The fracturing pump valve box suction cylinder according to claim 4, characterized in that: The end plug (9) has a Y-shaped packing groove (901) circumferentially opened on its outer peripheral surface, and a Y-shaped packing is provided in the Y-shaped packing groove (901); The end plug (9) and the stop part (8) are designed as an integrated unit, and the length of the overall structure formed by the end plug (9) and the stop part (8) is 82 to 93.5 mm. The outer wall of the Y-type packing groove (901) is 41mm to 45.5mm from the outer end face of the end plug (9).

6. A fracturing pump valve box, characterized in that: It includes a plunger chamber, a discharge cylinder, and a fracturing pump valve box suction cylinder as described in any one of claims 1 to 5; The plunger chamber, discharge cylinder, and suction cylinder are interconnected; The plunger cavity is provided with a plunger (1) that can reciprocate back and forth. When the plunger (1) moves backward, the suction valve body (5) moves upward against the pressure of the elastic element (4) to open the liquid inlet channel. When the plunger (1) moves forward, the suction valve body (5) moves downward under the pressure of the elastic element (4) to close the liquid inlet channel. The discharge chamber is provided with a discharge channel, as well as a discharge valve body and a discharge valve seat for opening and closing the discharge channel.

7. A fracturing pump valve box according to claim 6, characterized in that: The end plug mounting cavity is disposed opposite to the plunger cavity and is located on both sides of the suction cavity (11); When the end plug (9) is installed, the maximum deflection angle of the straightening frame (3) is α; When the end plug (9) is not installed and the plunger (1) is moved to the farthest end to form a stop on the straightening frame (3), the maximum deflection angle of the straightening frame (3) is β; The α is less than the β.

8. A fracturing pump valve box according to claim 7, characterized in that: The α value is 24° to 35°, and the β value is 37°.

9. A fracturing pump valve box according to claim 6, characterized in that: The straightening frame (3) is provided with a guide center hole (302) coaxially in the middle; Below the valve seat (6), at the connection between the liquid inlet channel (12) and the suction chamber (11), there is a support tray (7), and a vertical through-hole is opened in the middle of the support tray (7); The suction valve body (5) has an upper guide rod (501) and a lower guide rod (502) at its top center and bottom center, respectively; After installation, the upper guide rod (501) extends into the guide center hole (302), and the lower guide rod (502) extends into the through hole to guide the suction valve body (5) during the up and down movement of the suction valve body (5).

10. A fracturing pump valve box according to claim 9, characterized in that: The elastic element (4) is a spring; The bottom of the straightening frame (3) is provided with a spring positioning cylinder (303), and the guide center hole (302) passes through the spring positioning cylinder (303) downward; At the bottom of the straightening frame (3), a foot (304) is provided on each side of the spring positioning cylinder (303) so that the spring can be positioned by the spring positioning cylinder (303) and the two feet (304); After installation, the top of the spring is fitted outside the spring positioning cylinder (303) and abuts against the lower surface of the straightening frame (3), and the bottom of the spring is fitted outside the upper guide rod (501) and abuts against the upper surface of the suction valve body (5).

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