175MPa fluid end

Abstract

The utility model discloses a 175MPa fluid end which comprises a vertical through hole and a horizontal through hole which are intersected and communicated in the middle of a pump head body. The plunger is driven by the power end to do reciprocating rectilinear motion along the horizontal through hole; the blanking cap assembly and the plunger are oppositely arranged at the other end of the horizontal through hole and seal the horizontal through hole; the fixing base is of a sleeve structure, the fixing base and the horizontal through hole are coaxially arranged at the intersection of the two through holes, one end of the fixing base abuts against the inner wall of the pump head body, the other end of the fixing base abuts against the inner end of the blanking cap assembly, and through holes communicating with the vertical through hole are formed in the top and the bottom of the fixing base correspondingly; the suction valve assembly and the discharge valve assembly are oppositely arranged at the two ends of the vertical through hole and seal the vertical through hole. According to the utility model, the stress concentration degree of the intersecting line of the vertical through hole and the horizontal through hole in the pump head body and the root position of the blanking cap is reduced, and the service life of the fluid end in an ultrahigh pressure environment is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of fracturing pumps, and more specifically, to a 175MPa hydraulic end. Background Art

[0002] The fracturing pump is the core part of the fracturing construction in oil and gas field exploitation. It is mainly composed of two parts: the power end and the hydraulic end. The power end drives the plunger of the hydraulic end to reciprocate in the pump head body. The reciprocating motion of the plunger realizes the corresponding opening / closing of the valve assembly at the suction and discharge ends of the pump head body, thereby realizing the suction of low-pressure liquid and the discharge of high-pressure liquid. The pressurized fracturing fluid is transported to the bottom of the well through a high-pressure pipeline. At present, the maximum working pressure of the common hydraulic end structure is usually 80-140MPa. When the working pressure exceeds the limit range, the hydraulic end is prone to damage under the influence of excessively high pressure, which seriously affects the service life of the fracturing pump.

[0003] In actual applications, the damage forms of the hydraulic end mainly include structural cracking. Among them, there is stress concentration at the intersection line of the pump head body, which is prone to cracking during the circulation of high-pressure liquid; the plugging cover is set opposite the plunger, and the root of the plugging cover (the end adjacent to the plunger) is a stress concentration area, which is also prone to fatigue cracking under the action of cyclic load.

[0004] In order to solve the above problems, it is necessary to design a 175MPa hydraulic end so that it can be applied to a wider range of pressure environments and extend the service life of the fracturing pump in ultra-high pressure environments. Utility Model Content

[0005] The purpose of the utility model is to provide a 175MPa hydraulic end, which effectively improves the stability of the connection between the plugging cover assembly and the pump head body by adding a fixing seat between the plunger mechanism and the plugging cover assembly, and at the same time greatly reduces the intersection line of the vertical through hole and the horizontal through hole inside the pump head body and the stress concentration at the root position of the plugging cover, thereby extending the service life of the hydraulic end in an ultra-high pressure environment.

[0006] In order to achieve these purposes and other advantages according to the utility model, a 175MPa hydraulic end is provided, including a plurality of boosting devices, which are arranged inside the pump head body at intervals along the length direction, and any boosting device includes:

[0007] A vertical through hole and a horizontal through hole, which respectively penetrate the pump head body in the vertical and horizontal directions and intersect and communicate in the middle thereof;

[0008] A plunger mechanism, which is arranged at one end of the horizontal through hole, and the plunger mechanism includes a plunger, which performs reciprocating linear motion along the horizontal through hole under the drive of the power end; a first sealing device, which is arranged to close the gap between the plunger and the horizontal through hole;

[0009] A plugging cover assembly, which is fixedly disposed at the other end of the horizontal through hole and seals it;

[0010] A fixed seat, which is a sleeve structure, is coaxially arranged with the horizontal through hole at the intersection of the two through holes and has an inner diameter greater than the outer diameter of the plunger, one end of the fixed seat abuts against the inner wall of the pump head body, and the other end abuts against the inner end of the plugging cover assembly, and the top and bottom of the fixed seat are respectively provided with through holes communicating with the vertical through hole;

[0011] A suction valve assembly and a discharge valve assembly are arranged oppositely at two ends of the vertical through hole and seal them;

[0012] When the plunger moves in a direction away from the plugging cover assembly, the suction valve assembly opens and the discharge valve assembly closes; when the plunger moves in a direction close to the plugging cover assembly, the suction valve assembly closes and the discharge valve assembly opens.

[0013] Preferably, in the 175 MPa hydraulic end, the axes of the two through holes are located in the same plane, the two through holes form a cavity connected on four sides at the intersection, and the inflection points of the adjacent connecting channels are provided with double arc chamfers.

[0014] Preferably, for the 175MPa hydraulic end, the first sealing device includes a sealing gland, which is an annular structure, whose outer annular surface is fixedly sleeved with the end of the horizontal through hole, and whose inner annular surface is slidingly sleeved with the outer side wall of the plunger, and the sealing gland, the horizontal through hole and the plunger together form an annular cavity with one end closed; and a sealing filler, which is used to fill the annular cavity.

[0015] Preferably, the 175MPa hydraulic end, the horizontal through hole segment corresponding to the plugging cover assembly is expanded outward near the orifice to form a stepped hole, and the plugging cover assembly comprises: a plugging cover, which is fitted and sleeved on the narrow end of the stepped hole, the inner end surface of the plugging cover is a recessed spherical surface and abuts against the end of the fixing seat, and the outer end of the plugging cover is clamped at the step of the stepped hole; a locking nut, which is threadedly connected with the wide end of the stepped hole and presses the outer end of the plugging cover inward; a second sealing device, which is arranged in an annular groove located in the middle of the plugging cover and closes the gap between the plugging cover and the stepped hole.

[0016] Preferably, for the 175MPa hydraulic end, the second sealing device includes a support ring, which is fitted on the annular groove and has an inverted L-shaped cross-section, the vertical portion of the support ring is arranged tightly against the outer side wall of the annular groove, and the horizontal portion extends inward along the open end surface of the annular groove; a D-type sealing ring, which is clamped between the support ring and the inner side wall of the annular groove and fitted with the annular groove.

[0017] Preferably, for the 175 MPa hydraulic end, the difference between the diameter of the narrow end of the step hole and the outer diameter of the valve seat of the suction valve assembly or the discharge valve assembly is less than or equal to 11 mm.

[0018] Preferably, the 175MPa hydraulic end, the suction valve assembly includes a suction valve seat, which is fixed at the lower part of the vertical through hole and cooperates with it, and the middle part of the suction valve seat is provided with an axial through hole; a suction valve body, the upper diameter of which is larger than the diameter of the axial through hole and the lower part is slidably connected with the axial through hole; a guide seat, which is located directly above the suction valve body and fixed to the bottom of the fixed seat; a suction spring, which is arranged in the vertical direction and the two ends are respectively abutted against the guide seat and the suction valve body.

[0019] Preferably, the 175MPa hydraulic end, the discharge valve assembly includes a discharge valve seat, which is fixed on the upper part of the vertical through hole and cooperates with it, and the middle part of the suction valve seat is provided with an axial through hole; a discharge valve body, the upper diameter of which is larger than the diameter of the axial through hole and the lower part is slidably connected with the axial through hole; a discharge cover, which is arranged above the discharge valve body and is fixedly sleeved with the end of the vertical through hole; a discharge spring, which is arranged in the vertical direction and the two ends are respectively abutted against the discharge cover and the discharge valve body.

[0020] The utility model at least has the following beneficial effects:

[0021] 1. The utility model effectively improves the stability of the connection between the plugging cover assembly and the pump head body by adding a fixing seat between the plunger mechanism and the plugging cover assembly, and at the same time greatly reduces the stress concentration at the intersection line of the vertical through hole and the horizontal through hole inside the pump head body and the root position of the plugging cover, thereby extending the service life of the hydraulic end in an ultra-high pressure environment;

[0022] 2. The utility model eliminates the sealing groove at the root of the conventional plugging cover structure, and adopts a support ring and a D-shaped sealing ring to cooperate in sealing at the annular groove in the middle of the plugging cover. This can, to a certain extent, prevent the D-ring from being squeezed into the gap between the inner cavity of the pump head body and the plugging cover due to pressure when the pressure increases, thereby reducing the undercut of the D-ring, optimizing the sealing structure, and further improving the sealing performance and sealing service life of the plugging cover assembly.

[0023] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of a 175MPa hydraulic end according to an embodiment of the utility model;

[0025] Figure 2 AA cross-sectional structure schematic diagram of the 175MPa hydraulic end described in the above embodiment;

[0026] Figure 3 It is a structural schematic diagram of the plugging and covering assembly described in the above embodiment;

[0027] Figure 4 Schematic diagram of the structure of the second sealing device in the above embodiment.

[0028] Description of reference numerals:

[0029] 1. Clamp; 2. Plunger; 3. Sealing gland; 4. Pump head body; 41. Double arc chamfer; 5. Sealing packing; 6. Guide seat; 7. Fixed seat; 71. Through hole; 81. Suction valve seat; 82. Suction valve body; 83. Suction spring; 9. Mouth-shaped sealing ring; 10. Plug cover assembly; 101. Plug cover; 102. Locking nut; 103. Second sealing device; 104. D-type sealing ring; 105. Support ring; 11. Discharge valve assembly; 12. Discharge spring; 13. Discharge cover; 14. High-pressure manifold. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0031] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0032] like Figure 1-4As shown, the utility model provides a 175MPa hydraulic end, including a plurality of boosting devices, which are arranged inside the pump head body 4 at intervals along the length direction, and any boosting device includes:

[0033] A vertical through hole and a horizontal through hole, which respectively penetrate the pump head body 4 in the vertical and horizontal directions and intersect and communicate in the middle thereof;

[0034] A plunger mechanism, which is arranged at one end of the horizontal through hole, and the plunger mechanism includes a plunger 2, which performs reciprocating linear motion along the horizontal through hole under the drive of the power end; a first sealing device, which is arranged to close the gap between the plunger 2 and the horizontal through hole;

[0035] A plugging cover assembly 10, which is fixedly disposed at the other end of the horizontal through hole and seals it;

[0036] The fixing seat 7 is a sleeve structure, which is coaxially arranged with the horizontal through hole at the intersection of the two through holes and has an inner diameter greater than the outer diameter of the plunger 2. One end of the fixing seat 7 abuts against the inner wall of the pump head body 4, and the other end abuts against the inner end of the plugging cover assembly 10. The top and bottom of the fixing seat 7 are respectively provided with through holes 71 communicating with the vertical through holes;

[0037] A suction valve assembly and a discharge valve assembly 11, which are arranged oppositely at two ends of the vertical through hole and seal them;

[0038] Among them, when the plunger 2 moves in the direction away from the blocking cover assembly 10, the suction valve assembly opens and the discharge valve assembly 11 closes; when the plunger 2 moves in the direction close to the blocking cover assembly 10, the suction valve assembly closes and the discharge valve assembly 11 opens.

[0039] In the above technical solution, the 175MPa hydraulic end is applied to a fracturing pump, which also includes a power end, which is configured to drive the plunger action of the hydraulic end, and a conventional fracturing pump power end structure (such as a crank-connecting rod mechanism, etc.) can be selected. One end of the plunger 2 is located inside the horizontal through hole, and the other end extends outward from the horizontal through hole and is connected to the power end through a clamp 1. When the power end is working, the plunger 2 performs reciprocating linear motion along the axial direction of the horizontal through hole under the limiting action of the first sealing device. Specifically, the inner end of the plunger can move between the fixed seat and the first sealing device, such as Figure 2As shown, the limit movement position L of the inner end of the plunger toward the outside (to the left) is the inner end face of the first sealing device, and the limit movement position R of the inner end of the plunger toward the inside (to the right) is the end of the through hole adjacent to the discharge valve assembly on the fixed seat close to the plugging assembly, that is, to ensure that before the plunger moves inward to the limit position, the inner cavity of the fixed seat can maintain communication with the cavity where the discharge valve assembly is located. Both the suction valve assembly and the discharge valve assembly can adopt a conventional valve structure, and the valve seat and the valve body move relative to each other under pressure, and can realize the automatic opening and closing function, that is, open / close the end opening of the vertical through hole. The cavity between the first sealing device, the plugging cover assembly, the suction valve assembly and the discharge valve assembly is the relatively closed inner cavity of the pump head body. When the suction valve assembly is opened, the inner cavity of the pump head body is connected to the low-pressure liquid channel, and when the discharge valve assembly is opened, the inner cavity of the pump head body is connected to the high-pressure manifold.

[0040] The working principle of the booster device is as follows: in the initial state, the suction valve assembly and the discharge valve assembly are both in a closed state, and the inner cavity of the pump head body is in a completely closed state; when the plunger moves to the left, the inner cavity space of the pump head body increases to form a negative pressure, causing the suction valve assembly to gradually open, and the external low-pressure liquid (fracturing fluid) is drawn into the inner cavity of the pump head body from the end of the vertical through hole through the suction valve assembly, and at this time, the discharge valve assembly is in a closed state under the action of negative pressure. When the plunger moves to the right, the inner cavity space of the pump head body decreases, the pressure increases, and while high-pressure liquid is formed inside, the suction valve assembly is pressed down to close the corresponding end of the vertical through hole (low-pressure liquid channel), and at this time, the discharge valve assembly is automatically opened due to the increase in pressure, so that the high-pressure liquid formed in the inner cavity of the pump head body is discharged into the high-pressure manifold through the discharge valve assembly.

[0041] In view of the stress concentration at the intersection of the vertical through hole and the horizontal through hole in the pump head body (i.e., the intersection line) and the root of the plug cover assembly, which is prone to cracking, the utility model adds a fixed seat between the plunger mechanism and the plug cover assembly, one end of which abuts against the side (left side) of the intersection of the through holes close to the plunger, and the other end abuts against the inner end of the plug cover assembly. On the one hand, the fixed seat can be used as an auxiliary support structure to strengthen the structural strength of the pump head body at the intersection of the through holes, and when the high-pressure liquid circulates, the stress originally concentrated at the intersection line of the through holes will be shared by the fixed seat and evenly transmitted to other positions in the pump head body; on the other hand, the fixed seat can improve the integrity and stability of the connection between the plug cover assembly and the pump head body without affecting the displacement range of the plunger, thereby optimizing the force structure and effectively reducing the stress concentration inside the pump head body and the root of the plug cover. The hydraulic end structure of the utility model can be applied to 175MPa ultra-high pressure environment and reduce the risk of hydraulic end cracking, extending the service life of the hydraulic end in ultra-high pressure environment.

[0042] In another technical solution, in the 175MPa hydraulic end, the axes of the two through holes are located in the same plane, and the two through holes form a cavity connected on four sides at the intersection, and the inflection points of the adjacent connecting channels are provided with double arc chamfers 41. Figure 2 As shown, the intersection lines of the two through holes are cut in different directions to form a double arc chamfer structure with opposite outer arc surfaces, thereby further optimizing the stress structure of the inner cavity of the pump head body, reducing the stress concentration and stress peak at the intersection line, and effectively reducing the risk of cracking of the pump head body.

[0043] In another technical solution, the 175MPa hydraulic end, the first sealing device includes a sealing gland 3, which is an annular structure, whose outer ring surface is fixedly sleeved with the end of the horizontal through hole, and the inner ring surface is slidably sleeved with the outer wall of the plunger 2. The sealing gland 3, the horizontal through hole, and the plunger 2 together form an annular cavity with one end closed; a sealing filler 5, which is matched to fill the annular cavity. Among them, the first sealing device limits the moving direction of the plunger along the length direction to ensure that the plunger can accurately move linearly along the axial direction of the horizontal through hole. The sealing gland seals the open end of the horizontal through hole, the outer end of the annular cavity is sealed by the sealing gland, and the inner end is connected with the vertical through hole. The sealing filler is a packing, which is sleeved between the plunger and the transverse through hole. While assisting in sealing the gap between the plunger and the transverse through hole, the liquid from the inner cavity of the pump head body is immersed in the sealing filler, which can lubricate the relative sliding of the plunger and extend the service life of the end seal.

[0044] In another technical solution, the 175MPa hydraulic end, the horizontal through hole segment corresponding to the plugging cover assembly is expanded outward near the orifice to form a stepped hole, and the plugging cover assembly includes: a plugging cover 101, which is fitted on the narrow end of the stepped hole, the inner end surface of the plugging cover 101 is a recessed spherical surface and abuts against the end of the fixing seat 7, and the outer end of the plugging cover 101 is clamped at the step of the stepped hole; a locking nut 102, which is threadedly connected to the wide end of the stepped hole and presses the outer end of the plugging cover 101 inward; a second sealing device 103, which is arranged in an annular groove located in the middle of the plugging cover and closes the gap between the plugging cover 101 and the stepped hole.

[0045] Among them, the root of the plug cover is a stress concentration area, which is prone to fatigue cracking under cyclic loads. In the above technical solution, the sealing groove at the root of the conventional plug cover structure is cancelled, and an annular groove is set in the middle of the plug cover for sealing, which can reduce the loss of sealing caused by stress concentration to a certain extent. At the same time, a chamfer can be added at the root (inner end) of the plug cover to reduce stress concentration. Specifically, the plug cover and the locking nut can be made of alloy structural steel materials to improve the stress corrosion resistance and fatigue performance of the plug cover assembly.

[0046] In addition, damage to the hydraulic end also includes seal failure. Under high pressure in circulation, the gap between the inner cavity of the pump head and the plug cap changes constantly, which can easily cause the seal at this position to be squeezed into the gap and gradually torn, leading to seal failure of the plug cap. In the above technical solution, after the inner end surface of the plug cap is changed to a spherical surface, the radial direction will also be stressed to make up for the gap formed by the expansion of the inner cavity of the pump head due to the pressure, thereby reducing the fracturing fluid from entering the sealing ring position, which is conducive to reducing seal wear and extending the service life of the seal at this location.

[0047] In another technical solution, the 175MPa hydraulic end, the second sealing device includes a support ring 105, which is fitted on the annular groove and has an inverted L-shaped cross section, the vertical portion of the support ring 105 is arranged close to the outer wall of the annular groove, and the horizontal portion extends inward along the open end surface of the annular groove; a D-type sealing ring 104, which is clamped between the support ring 105 and the inner wall of the annular groove and is fitted with the annular groove. Specifically, the support ring is made of POM material with high strength and rigidity, and its thickness is equal to the depth of the annular groove, and the D-type sealing ring is made of PU material, and its thickness is greater than the depth of the annular groove. The D-type sealing ring (D-ring) forms an L-shaped contact surface with the support ring on the non-pressure side, which can avoid the D-ring from being squeezed into the inner cavity (horizontal through hole) of the pump head body and the gap formed by the pressure of the plug cover when the pressure increases to a certain extent, thereby reducing the undercut of the D-ring, optimizing the sealing structure, further improving the sealing performance of the plug cover assembly, and extending the service life of the seal there.

[0048] In another technical solution, for the 175 MPa hydraulic end, the difference between the diameter of the narrow end of the step hole and the outer diameter of the valve seat of the suction valve assembly or the discharge valve assembly is less than or equal to 11 mm.

[0049] There is stress concentration at the root of the plug cover and the root of the first thread of its locking nut, which is prone to fatigue cracking under cyclic load, leading to sealing failure, the inability to continue to use the hydraulic end, and other problems. In the above technical solution, the narrow end diameter of the step hole is set to D1, and the outer diameter of the valve seat in the valve assembly for liquid suction / discharge is set to D2. The solution of reducing the inner diameter of the horizontal through hole where the plug cover is located is adopted, and D1≤D2+11 is limited to reduce the aperture of the through hole where the plug cover is located, thereby reducing the load on the root and thread of the plug cover and improving the bearing capacity of the plug cover. At the same time, the wide end diameter of the step hole can be appropriately increased to increase the thread specifications matched therewith, thereby improving the bearing capacity of the locking nut at the horizontal through hole.

[0050] In another technical solution, the 175MPa hydraulic end, the suction valve assembly includes a suction valve seat 81, which is fixed at the lower part of the vertical through hole and cooperates with it, and the middle part of the suction valve seat 81 is provided with an axial through hole; a suction valve body 82, the upper diameter of which is larger than the diameter of the axial through hole and the lower part is slidably connected with the axial through hole; a guide seat 6, which is located directly above the suction valve body 82 and fixed at the bottom of the fixed seat 7; a suction spring 83, which is arranged in the vertical direction and the two ends are respectively abutted against the guide seat 6 and the suction valve body 82.

[0051] Among them, the fixed seat provides a relatively stable installation platform for the guide seat, and the through holes 71 at the bottom of the fixed seat 7 can be opened on both sides of the guide seat 6, which will not affect the circulation of the liquid. In addition, a through hole can also be opened in the middle of the guide seat 6 for the circulation of the liquid inside and outside the fixed seat; a suction cavity is formed between the guide seat 6 and the suction valve body 82, and the suction spring 83 is a compression spring, and its two ends are fixedly connected to the guide seat 6 and the suction valve body 82 respectively. Therefore, when there is no pressure (in the initial state), the suction valve body 82 presses the suction valve seat 81 downward under the action of the suction spring 83, that is, the upper structure of the suction valve body closes the axial through hole of the suction valve seat from the top, the suction valve assembly is in a closed state, and the inner cavity of the pump head body is not connected to the low-pressure channel. When the plunger 2 moves to the left, negative pressure is formed in the inner cavity of the pump head body, and the suction valve body 82 overcomes the pressure of the suction spring 83 and moves upward along the axial through hole, so that the axial through hole is opened (connecting the low-pressure channel below with the suction chamber above), and the suction valve assembly is in an open state, and low-pressure liquid is drawn into the suction chamber and circulates in the inner cavity of the pump head body. When the plunger 2 moves to the right, the inner cavity of the pump head body is pressurized, and the suction valve body 82 presses down against the suction valve seat 81 under the action of the suction spring and pressure, and the suction valve assembly returns to a closed state, and the liquid will not flow back to the low-pressure channel.

[0052] To ensure sealing, a mouth-shaped sealing ring 9 is provided between the suction valve seat 82 and the vertical through hole.

[0053] In another technical solution, the 175MPa hydraulic end, the discharge valve assembly 11 includes a discharge valve seat, which is fixed on the upper part of the vertical through hole and cooperates with it, and the middle part of the suction valve seat is provided with an axial through hole; a discharge valve body, whose upper diameter is larger than the diameter of the axial through hole and the lower part is slidably connected with the axial through hole; a discharge cover 13, which is arranged above the discharge valve body and is fixedly sleeved with the end of the vertical through hole; a discharge spring 12, which is arranged in the vertical direction and its two ends are respectively abutted against the discharge cover 13 and the discharge valve body.

[0054] Among them, the discharge cover 13 closes the end (top) of the vertical through hole, and a discharge cavity is formed between the discharge cover 13 and the discharge valve body. The high-pressure liquid entering the discharge cavity is discharged through the high-pressure manifold. The discharge spring 12 is a compression spring, and its two ends are fixedly connected to the discharge cover 13 and the discharge valve body respectively. The working principle of the discharge valve assembly is basically the same as that of the suction valve assembly. When there is no pressure (in the initial state), the discharge valve body presses the discharge valve seat downward under the action of the discharge spring 12, that is, the upper structure of the discharge valve body closes the axial through hole of the discharge valve seat from the top, and the discharge valve assembly 11 is in a closed state, and the inner cavity of the pump head body is not connected to the high-pressure manifold. When the plunger 2 moves to the left, a negative pressure is formed in the inner cavity of the pump head body. The discharge valve body is stably maintained in a closed state under the action of the negative pressure and the pressure of the discharge spring 12, and the low-pressure liquid will not flow into the high-pressure manifold 14. When the plunger 2 moves to the right, the pump head body cavity is pressurized, and the discharge valve body overcomes the pressure of the discharge spring 12 and moves upward along the corresponding axial through hole, so that the axial through hole is opened (connecting the pump head body cavity below and the discharge cavity above), and the discharge valve assembly 11 is in an open state. After the liquid is pressurized in the pump head body cavity, it is squeezed into the suction cavity through the axial through hole and enters the high-pressure manifold 14 for circulation. At the same time, in order to ensure the sealing performance, a mouth-shaped sealing ring is also provided between the discharge valve seat and the vertical through hole.

[0055] In addition, the vertical through hole segment corresponding to the discharge valve assembly is expanded outward near the orifice to form a step hole, the discharge cover is fitted over the narrow end of the step hole and the outer end is clamped on the step of the step hole, and a locking nut is also correspondingly provided on the top of the discharge cover, which is threadedly connected with the wide end of the step hole and presses the top of the discharge cover downward (inward), thereby ensuring the installation stability and sealing reliability of the discharge cover.

[0056] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A 175MPa hydraulic end, characterized in that: It includes a plurality of boosting devices, which are arranged inside the pump head body at intervals along the length direction, and any boosting device includes: A vertical through hole and a horizontal through hole, which respectively penetrate the pump head body in the vertical and horizontal directions and intersect and communicate in the middle thereof; A plunger mechanism, which is arranged at one end of the horizontal through hole, and the plunger mechanism includes a plunger, which performs reciprocating linear motion along the horizontal through hole under the drive of the power end; a first sealing device, which is arranged to close the gap between the plunger and the horizontal through hole; A plugging cover assembly, which is fixedly disposed at the other end of the horizontal through hole and seals it; A fixed seat, which is a sleeve structure, is coaxially arranged with the horizontal through hole at the intersection of the two through holes and has an inner diameter greater than the outer diameter of the plunger, one end of the fixed seat abuts against the inner wall of the pump head body, and the other end abuts against the inner end of the plugging cover assembly, and the top and bottom of the fixed seat are respectively provided with through holes communicating with the vertical through hole; A suction valve assembly and a discharge valve assembly are arranged oppositely at two ends of the vertical through hole and seal them; When the plunger moves in a direction away from the plugging cover assembly, the suction valve assembly opens and the discharge valve assembly closes; when the plunger moves in a direction close to the plugging cover assembly, the suction valve assembly closes and the discharge valve assembly opens.

2. The 175 MPa hydraulic end according to claim 1, characterized in that: The axes of the two through holes are located in the same plane, and the two through holes form a cavity connected on four sides at the intersection, and double arc chamfers are provided at the turning points of the adjacent connecting channels.

3. The 175 MPa hydraulic end according to claim 1, characterized in that: The first sealing device comprises a sealing gland, which is an annular structure, whose outer annular surface is fixedly sleeved with the end of the horizontal through hole, and whose inner annular surface is slidably sleeved with the outer side wall of the plunger, and the sealing gland, the horizontal through hole and the plunger together form an annular cavity closed at one end; A sealing filler is matched to fill the annular cavity.

4. The 175 MPa hydraulic end according to claim 1, characterized in that: The horizontal through hole segment corresponding to the plugging cover assembly is expanded outward near the hole mouth to form a stepped hole, and the plugging cover assembly includes: a plugging cover, which is fitted and sleeved on the narrow end of the stepped hole, the inner end surface of the plugging cover is a recessed spherical surface and abuts against the end of the fixing seat, and the outer end of the plugging cover is clamped at the step of the stepped hole; a locking nut, which is threadedly connected with the wide end of the stepped hole and presses the outer end of the plugging cover inward; a second sealing device, which is arranged in an annular groove located in the middle of the plugging cover and closes the gap between the plugging cover and the stepped hole.

5. The 175 MPa hydraulic end according to claim 4, characterized in that: The second sealing device includes a support ring, which is fitted on the annular groove and has an inverted L-shaped cross-section, the vertical portion of the support ring is arranged tightly against the outer wall of the annular groove, and the horizontal portion extends inward along the open end surface of the annular groove; a D-type sealing ring, which is clamped between the support ring and the inner side wall of the annular groove and fits with the annular groove.

6. The 175 MPa hydraulic end according to claim 4, characterized in that: The difference between the narrow end diameter of the step hole and the outer diameter of the valve seat of the suction valve assembly or the discharge valve assembly is less than or equal to 11 mm.

7. The 175 MPa hydraulic end according to claim 1, characterized in that: The suction valve assembly includes a suction valve seat, which is fixed at the lower part of the vertical through hole and cooperates with it, and an axial through hole is provided in the middle of the suction valve seat; a suction valve body, whose upper diameter is larger than the diameter of the axial through hole and whose lower part is slidably connected with the axial through hole; a guide seat, which is located directly above the suction valve body and fixed at the bottom of the fixed seat; and a suction spring, which is arranged in the vertical direction and whose two ends are respectively abutted against the guide seat and the suction valve body.

8. The 175 MPa hydraulic end according to claim 1, characterized in that: The discharge valve assembly includes a discharge valve seat, which is fixed on the upper part of the vertical through hole and cooperates with it, and an axial through hole is provided in the middle of the discharge valve seat; a discharge valve body, whose upper diameter is larger than the diameter of the axial through hole and whose lower part is slidably connected with the axial through hole; a discharge cover, which is arranged above the discharge valve body and cooperates with the end of the vertical through hole to be fixed and sleeved; a discharge spring, which is arranged in the vertical direction and whose two ends are respectively abutted against the discharge cover and the discharge valve body.

Images