Three-cylinder reciprocating pump

Abstract

The utility model relates to the technical field of reciprocating pumps, and provides a three-cylinder reciprocating pump which comprises a shell with a through hole. The fluid end assembly is arranged on one side of the shell; the crank-link mechanism is arranged on the shell, and the crank-link mechanism comprises a power input end and a power output end; the driving shaft is rotationally arranged on the shell and is in transmission connection with the power input end; the pull rod is arranged in the shell in a reciprocating sliding manner; one end of the pull rod is arranged on the power output end; one end of the displacement piece penetrates through and is slidably arranged on the fluid end assembly, and the other end of the displacement piece is arranged at the other end of the pull rod. By means of the technical scheme, the problems that in the prior art, a reciprocating pump is large in size, heavy in weight, low in rotating speed, large in operation noise and the like are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to reciprocating pump technical field, specifically, it relates to a three cylinder reciprocating pump. BACKGROUND

[0002] At present, the reciprocating pump (also called mud pump) used in the drilling exploration industry mainly is F series and 3NB series products, the power range is 350HP and above, is matched with the geological exploration drilling rig matched with the drilling depth of 1500~3000m, the reciprocating pump above 350HP is big in size, heavy in weight, high in procurement cost, the double cylinder double acting reciprocating pump that also satisfies this working condition requirement, this pump is low in rotating speed, heavy in weight, many in wearing parts, big in power end gear operation noise, and high in maintenance cost. SUMMARY

[0003] The utility model provides a three cylinder reciprocating pump, solve reciprocating pump big size, heavy weight, pump low rotating speed and big operating noise etc.

[0004] The technical scheme of the utility model is as follows:

[0005] A three cylinder reciprocating pump, comprising:

[0006] The shell has a through hole;

[0007] The hydraulic end assembly is arranged on one side of the shell;

[0008] The crank connecting rod mechanism is arranged on the shell, and the crank connecting rod mechanism comprises a power input end and a power output end;

[0009] The drive shaft is rotatably arranged on the shell, and the drive shaft is in transmission connection with the power input end;

[0010] The pull rod is reciprocally and slidably arranged in the shell, and one end of the pull rod is arranged on the power output end;

[0011] The displacement piece is arranged on the hydraulic end assembly in a penetrating and sliding manner, and the other end of the displacement piece is arranged on the other end of the pull rod.

[0012] Optionally, the crank connecting rod mechanism comprises:

[0013] The crankshaft is rotatably arranged on the shell, and the crankshaft has a plurality of crank necks and crank webs;

[0014] The connecting rod has a plurality of connecting rods, and one end of each connecting rod is rotatably arranged at one crank web, and the other end of the connecting rod is hingedly connected with one end of the pull rod;

[0015] A first gear is arranged on the crankshaft, the first gear is coaxially arranged with the two end faces of the crankshaft, and the first gear is in transmission connection with the drive shaft.

[0016] Optionally, the drive shaft is located obliquely above the crankshaft, and the method further comprises:

[0017] A second gear is arranged on the drive shaft, the second gear is in meshing connection with the first gear, and the first gear and the second gear are both in the form of herringbone tooth.

[0018] Optionally, the width of the first gear ranges from 150 mm to 240 mm, the width of the second gear ranges from 160 mm to 250 mm, and the transmission ratio of the first gear to the second gear ranges from 4.1:1 to 5:1.

[0019] Optionally, the crank neck is fixedly connected with the crank, and the distance between the rotation center of the crank neck and the crank ranges from 80 mm to 90 mm.

[0020] Optionally, the method further comprises:

[0021] A guide plate is arranged in the housing;

[0022] A crosshead assembly is slidably arranged on the guide plate, and the connecting rod is connected with the connecting rod through the crosshead assembly;

[0023] A sealing element is arranged on the outer wall of the housing, the sealing element is located at the through hole, and the connecting rod slidably penetrates through the sealing element.

[0024] Optionally, the sealing element comprises:

[0025] A sealing box is detachably arranged on the outer wall of the guide plate away from the connecting rod;

[0026] A bellows is sleeved on the connecting rod, one end of the bellows is arranged on the sealing box, and the other end of the bellows is arranged on the end face of the connecting rod away from the sealing box.

[0027] Optionally, the sealing box has an oil return groove, and the sealing box comprises:

[0028] A box body;

[0029] An oil seal ring is arranged in the box body, and the oil seal ring is sleeved on the connecting rod;

[0030] A plurality of skeleton oil seals are arranged on both sides of the oil seal ring

[0031] A sealing ring is arranged in the inner recess of the oil seal ring;

[0032] A fixing card is arranged in the box body and located outside the skeleton oil seal close to the bellows.

[0033] Optionally, the hydraulic end assembly further comprises a safety valve assembly, an air pack assembly and a discharge pipeline assembly, and the safety valve assembly, the air pack assembly and the discharge pipeline assembly are arranged on both sides of the hydraulic end assembly.

[0034] Optionally, the hydraulic end assembly further comprises:

[0035] A base is detachably arranged at the bottom of the shell.

[0036] The working principle and beneficial effects of the utility model are as follows:

[0037] Compared with the traditional high-power reciprocating pump, the utility model has a more compact overall structure and reduces the weight of the pump. The three-cylinder structure makes the output flow of the pump more uniform, reduces pressure fluctuation, improves the working stability and reliability of the pump, is suitable for some working conditions requiring pump volume and weight, and increases the power by increasing the stroke, increasing the speed and improving the working pressure, and simultaneously meets the conditions of drilling and filling operation in terms of weight and power by reducing the cylinder spacing and reducing the weight of the parts, thereby improving the working efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0038] The above features, technical characteristics, advantages and implementation modes of the utility model will be further described in the following preferred embodiments in a clear and understandable manner combined with the drawings.

[0039] Figure 1 It is an external structure diagram of the reciprocating pump of the utility model;

[0040] Figure 2 It is a top view of the reciprocating pump of the utility model;

[0041] Figure 3 It is a shell structure diagram of the utility model;

[0042] Figure 4 It is Figure 3 It is a local enlarged view of A-A;

[0043] Figure 5 It is Figure 3 It is a local enlarged view of B-B;

[0044] Figure 6 It is a crosshead assembly structure diagram of the utility model;

[0045] Figure 7 It is Figure 6 It is a local enlarged view of C;

[0046] Figure 8 It isFigure 4 Local enlarged view at D-D.

[0047] In the figure: 1, housing; 101, through hole; 2, fluid end assembly; 201, safety valve assembly; 202, air pocket assembly; 203, discharge pipeline assembly; 3, base; 4, drive shaft; 401, second gear; 5, crank connecting rod mechanism; 501, first gear; 50, crankshaft; 51, crank neck; 52, crank; 6, displacement piece; 7, bellows; 8, guide plate; 9, crosshead assembly; 10, connecting rod; 11, pull rod; 12, sealing piece; 1201, sealing box; 1202, oil seal ring; 1203, skeleton oil seal; 1204, sealing ring; 1205, fixed clamp. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, specific embodiments of the present application will be described below with reference to the drawings. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0049] In order to make the drawing simple, only the parts related to the present application are shown in each drawing, which does not represent the actual structure of the product. In addition, in order to make the drawing simple and easy to understand, in some drawings, only one of the components with the same structure or function is shown, or only one of them is marked. In this paper, "one" not only means "only one", but also means "more than one", and "several" includes "two" and "more than two".

[0050] In this paper, it should be noted that unless otherwise specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] In addition, in the description of the present application, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0052] Reference Figures 1-8For an embodiment of the utility model, propose a three cylinder reciprocating pump, including casing 1, have through -hole 101, hydraulic end assembly 2 set up in casing 1 one side, crank connecting rod mechanism 5 set up on casing 1, and crank connecting rod mechanism 5 includes power input end and power output end, driving shaft 4 rotation set up on casing 1, and driving shaft 4 is connected with power input end transmission, pull rod 11 reciprocating sliding set up in casing 1, and pull rod 11 one end set up on power output end, displacement piece 6 one end penetrates and sliding set up on hydraulic end assembly 2, and the other end of displacement piece 6 set up on pull rod 11 other end.

[0053] In the above scheme, casing 1 adopts steel sheet welding and becomes cuboid shape, and through-hole 101 is located at the side of casing 1, and the hole diameter is set according to the size of pull rod 11 to ensure that pull rod 11 can reciprocate smoothly and seal well. Hydraulic end assembly 2 has a high-precision displacement piece working cavity inside, which is tightly matched with displacement piece 6, installed on one side of casing 1, and fixedly connected through bolts to ensure firm connection and reliable sealing. The crankshaft 50 in the crank connecting rod mechanism 5 is installed in the casing 1 through a bearing seat. It should be noted that the displacement piece 6 is a cylinder sleeve, a cylinder barrel, etc.

[0054] The external power source drives the driving shaft 4 to rotate, and the gear on the driving shaft 4 is engaged with the first gear 501 on the crankshaft 50 to transmit power to the crankshaft 50. The crankshaft 50 rotates around its axis in the casing 1, and due to the eccentric effect of the crank 52, it drives the connecting rod 10 to reciprocate, which in turn pushes the pull rod 11 to move linearly along the through-hole 101 in the casing 1, and the pull rod 11 drives the displacement piece 6 to move linearly in the plunger cavity of the hydraulic end assembly 2, thereby converting mechanical energy into liquid pressure energy of the hydraulic end, achieving the purpose of conveying liquid.

[0055] Compared with traditional high-power reciprocating pumps, the overall structure is compact, reducing the weight of the pump. The three-cylinder structure makes the output flow of the pump more uniform, reduces pressure fluctuations, improves the working stability and reliability of the pump, and is suitable for some working conditions that require pump volume and weight. The device increases the stroke, increases the speed and improves the working pressure to increase the power, and at the same time reduces the cylinder spacing, reduces the number of gear teeth and reduces the thickness of the first gear 501 and the second gear 401 to reduce the self-weight. The light three-cylinder reciprocating pump meets the conditions of drilling and filling operation in terms of weight and power, improving work efficiency.

[0056] Further, the crank connecting rod mechanism 5 comprises a crankshaft 50 rotatably arranged on the shell 1, the crankshaft 50 has a plurality of crank pins 51 and crank webs 52; the connecting rods 10 are provided in plurality, one end of each connecting rod 10 is rotatably arranged at one crank web 52, the other end of the connecting rod 10 is hingedly connected with one end of the pull rod 11; the first gear 501 is arranged on the crankshaft 50, the first gear 501 is coaxially arranged with the two end faces of the crankshaft 50, and the first gear 501 is in transmission connection with the driving shaft 4.

[0057] In the above scheme, due to the eccentric structure of the crank pins 51 and the crank webs 52 on the crankshaft 50 and the transmission effect of the connecting rods 10, the rotary motion of the crankshaft 50 is converted into the reciprocating linear motion of the pull rod 11 and the displacement member 6, realizing the suction and discharge process of the liquid. The rotary motion of the driving shaft 4 can be effectively converted into the reciprocating motion of the displacement member 6, the structure is simple and reliable, easy to process and maintain. The multi-cylinder structure cooperates with the reasonable design of the crankshaft 50, so that the working process of the pump is more stable, the vibration and noise are reduced, the service life and working efficiency of the pump are improved, and compared with the traditional double-cylinder double-acting reciprocating pump, it has obvious advantages.

[0058] Further, the driving shaft 4 is located obliquely above the crankshaft 50, and further comprises a second gear 401 arranged on the driving shaft 4, the second gear 401 is in meshing with the first gear 501, and the second gear 401 and the first gear 501 are both in the form of double helical teeth.

[0059] In the above scheme, the driving shaft 4 is located obliquely above the crankshaft 50 at a position of 30°-45°, and is installed on the shell 1 through a bearing seat to ensure its rotation accuracy and stability. The second gear 401 adopts the same material and processing technology as the first gear 501, and the meshing of the double helical teeth can improve the load capacity and transmission stability of the gear and reduce the axial force. The second gear 401 is fixed on the driving shaft 4 through a key connection, which ensures good transmission effect and running stability. Due to the meshing characteristics of the double helical teeth, the power transmission is more stable and can bear larger load, so that the crankshaft 50 can stably rotate, thereby driving the connecting rod 10, the pull rod 11 and the displacement member 6 to work, realizing the liquid conveying function of the reciprocating pump. The oblique arrangement of the driving shaft 4 and the crankshaft 50 and the application of the double helical gear effectively optimize the power transmission path, improve the meshing performance and transmission efficiency of the gear, reduce the noise and vibration in the running process of the gear, enhance the reliability and stability of the whole pump, and at the same time, it is also conducive to the overall structural layout of the pump, making it more compact and reasonable.

[0060] Further, the width of the first gear 501 ranges from 150 to 240 mm, the width of the second gear 401 ranges from 160 to 250 mm, and the transmission ratio of the first gear 501 and the second gear 401 is 4.1:1-5:1.

[0061] In the above scheme, the width of the first gear 501 is designed as 180mm, the width of the second gear 401 is designed as 200mm, according to the working parameters and speed requirements of the pump, the appropriate modulus and the number of teeth are selected, so that the transmission ratio of the first gear 501 and the second gear 401 is 4.5:1. In the operation process of the pump, the second gear 401 on the driving shaft 4 rotates at the designed speed, and through the meshing with the first gear 501, the speed is reduced by 4.5:1 and transmitted to the crankshaft 50, so that the crankshaft 50 can rotate at a suitable speed, and then drive the displacement member 6 to move reciprocatingly, realizing the liquid delivery function of the pump, while ensuring that the working pressure and flow of the pump meet the design requirements.

[0062] Reasonable gear width and transmission ratio design can optimize the power transmission of the pump, so that the pump can meet the working performance requirements, reduce the speed of the crankshaft 50, reduce the wear and fatigue damage of the parts, and improve the reliability and service life of the pump. At the same time, it is also helpful to optimize the overall structure and size of the pump, and reduce the manufacturing cost and operation cost of the pump.

[0063] Further, the crank neck 51 is fixedly connected with the crank 52, and the distance between the rotation centers of the crank neck 51 and the crank 52 is 80-90mm.

[0064] In the above scheme, the distance between the rotation centers of the crank neck 51 and the crank 52 is accurately processed as 85mm, through high-precision processing technology and detection means, the size accuracy is controlled within ±0.05mm, the surface roughness reaches Ra0.8-Ra1.6μm, after nitriding treatment, the surface hardness and wear resistance are improved, and the stability and reliability of the crankshaft 50 in the long-term operation process are ensured.

[0065] The accurate distance between the rotation centers of the crank neck 51 and the crank 52 can accurately control the displacement of the pump and meet the requirements of liquid delivery under different working conditions. At the same time, by optimizing the structure and improving the machining precision, the strength and wear resistance of the crankshaft 50 are enhanced, the energy loss and mechanical failure of the pump in the operation process are reduced, and the overall performance and reliability of the pump are improved.

[0066] Further, it also includes a guide plate 8 arranged in the housing 1; the crosshead assembly is slidingly arranged on the guide plate 8, the pull rod 11 is connected with the connecting rod 10 through the crosshead assembly; the sealing element 12 is arranged on the outer wall of the housing 1, the sealing element 12 is located at the through hole 101, and the pull rod 11 slides through the sealing element 12.

[0067] In the above scheme, the crosshead assembly can smoothly slide on the guide plate 8, reducing friction and wear. The pull rod 11 is connected to the crosshead assembly through a pin, ensuring the reliability and flexibility of the connection. The sealing element 12 adopts a combination of rubber and metal structure, and the sealing box 1201 is detachably installed on the outer wall of the guide plate 8 away from the connecting rod 10 by bolts, facilitating the replacement of the sealing element 12. The bellows 7 is made of oil-resistant rubber, one end is fixed on the sealing box 1201 by a clamp, and the other end is fixed on the end face of the pull rod 11 by sealing glue, ensuring good sealing performance and preventing liquid leakage and dust from entering the inside of the housing 1.

[0068] During the operation of the pump, the crosshead assembly slides linearly on the guide plate 8 with the reciprocating movement of the pull rod 11, and the guide plate 8 provides guidance for the crosshead assembly, ensuring the stability of the movement trajectory of the pull rod 11, so that the displacement element 6 can accurately reciprocate in the fluid end assembly 2. The sealing element 12 is installed in the through hole 101 of the outer wall of the housing 1, sealing the pull rod 11, preventing liquid from leaking from the through hole 101, and preventing external impurities from entering the inside of the housing 1, protecting the internal parts of the pump from contamination and damage, ensuring the normal operation and working performance of the pump. Effectively improve the stability and precision of the movement of the pull rod 11, reduce the friction and wear between the pull rod 11 and the housing 1, prolong the service life of the parts. The setting of the sealing element 12 can reliably prevent leakage and impurities from entering, improve the working reliability and environmental adaptability of the pump, reduce the maintenance cost and downtime, and ensure that the pump can stably operate in a relatively harsh working environment.

[0069] Further, the sealing element 12 includes a sealing box 1201, which is detachably arranged on the outer wall of the guide plate 8 away from the connecting rod 10; the bellows 7 is sleeved on the pull rod 11, one end of the bellows 7 is arranged on the sealing box 1201, and the other end of the bellows 7 is arranged on the end face of the pull rod 11 away from the sealing box 1201.

[0070] In the above scheme, during the operation of the pump, when the pull rod 11 reciprocates in the sealing element 12, the oil seal ring 1202, the skeleton oil seal 1203 and the sealing ring 1204 jointly seal the pull rod 11, preventing lubricating oil from leaking between the pull rod 11 and the sealing box 1201. A small amount of leaked lubricating oil is collected by the oil return groove and then flows back to the pump's oil return system for recycling. The fixed clamp 1205 ensures the stability of the position of the skeleton oil seal 1203, so that it can continuously and effectively play a sealing role, thereby ensuring the sealing performance and normal operation of the pump. The combination of multiple sealing elements forms a multi-level sealing system, greatly improving the sealing performance, effectively preventing the leakage of lubricating oil, reducing the pollution to the working environment, and the good sealing performance helps to maintain the cleanliness and lubrication conditions inside the pump, prolonging the service life of the pump and reducing the maintenance and operation costs.

[0071] Further, the sealing box 1201 has an oil return groove, the sealing box 1201 comprises a box body; an oil seal ring 1202 is arranged in the box body, the oil seal ring 1202 is sleeved on the pull rod 11; a plurality of skeleton oil seals 1203 are arranged, the plurality of skeleton oil seals 1203 are arranged on both sides of the oil seal ring 1202 respectively, and are arranged in recessed portions inside the oil seal ring 1202; a fixing clamp 1205 is arranged in the box body, and the fixing clamp 1205 is located outside the skeleton oil seals 1203 close to the bellows 7.

[0072] In the above scheme, the box body facilitates installation and replacement of the oil seal ring 1202, the skeleton oil seals 1203, the sealing ring 1204 and the fixing clamp 1205. The oil seal ring 1202 can ensure good sealing effect and movement flexibility of the pull rod 11. The double lips of the skeleton oil seals 1203 face different directions respectively, the outer lip prevents foreign matters from entering, and the inner lip prevents lubricating oil from leaking, and installation ensures close fit with the oil seal ring 1202 and the box body. The cross-sectional shape of the sealing ring 1204 is designed as a circle, and the sealing ring 1204 is installed in an annular groove inside the oil seal ring 1202 and is in close contact with the surface of the pull rod 11, thereby forming a reliable sealing defense line. The fixing clamp 1205 adopts an elastic clamp structure, can firmly fix the skeleton oil seals 1203, is convenient for installation and disassembly, and a corresponding clamping groove is arranged on the box body, thereby ensuring that the installation position of the fixing clamp 1205 is accurate and correct.

[0073] In the operation process of the pump, the sealing elements work cooperatively, the oil seal ring 1202 first performs preliminary sealing on the pull rod 11, the double lips of the skeleton oil seals 1203 further enhance the sealing effect, the sealing ring 1204 fills possible small gaps, prevents lubricating oil from leaking and foreign matters from entering. The fixing clamp 1205 ensures that the skeleton oil seals 1203 do not displace in the working process, thereby ensuring stability and reliability of the entire sealing system, so that efficient sealing of the pull rod 11 is realized, and normal operation and good performance of the pump are ensured.

[0074] Further, the safety valve assembly 201, the air pack assembly 202 and the exhaust pipeline assembly 203 are arranged on both sides of the fluid end assembly 2.

[0075] In the above scheme, the safety valve assembly 201 is installed on the outlet pipeline of the fluid end assembly 2 by threaded connection with a spring safety valve. When the outlet pressure of the pump exceeds the set value, the safety valve automatically opens to return part of the liquid to the inlet of the pump or other safe discharge position to protect the pump and the entire system from damage caused by excessive pressure. The air pack is filled with gas at a certain pressure and is installed near the outlet of the fluid end assembly 2 and connected to the outlet through a pipeline. The compressibility of the gas in the air pack is used to absorb and buffer the pressure fluctuations generated by the pump during operation, making the output pressure of the pump more stable and reducing the impact on the pipeline and other equipment. The discharge pipeline assembly 203 is made of high-strength seamless steel pipe. The pipe diameter is reasonably selected according to the flow rate and working pressure of the pump. The pipes are connected by welding or flange connection to ensure firm connection and reliable sealing. The liquid discharged by the pump is transported to the designated work site.

[0076] During normal operation of the pump, the safety valve is in a closed state. When the outlet pressure of the pump rises above the opening pressure of the safety valve, the spring of the safety valve is compressed, the valve core is opened, and part of the liquid is returned, thereby reducing the outlet pressure and protecting the safety of the pump and the system. During operation of the pump, when the pressure of the pump rises, the liquid compresses the gas in the air pack, storing part of the energy. When the pressure of the pump decreases, the gas in the air pack expands, releasing the stored energy and supplementing the pressure of the liquid, thereby effectively smoothing the pressure fluctuations of the pump and making the output pressure of the pump more stable. The discharge pipeline assembly 203 transports the liquid discharged by the pump to the corresponding work position according to the design requirements, ensuring the normal operation of the entire system. The safety valve assembly 201 provides overpressure protection for the pump and the entire system, avoiding damage to equipment and safety accidents caused by excessive pressure, and improving the safety and reliability of the system. The air pack assembly 202 can significantly reduce the pressure fluctuations of the pump, improve the working stability of the pump and the quality of the delivered liquid, reduce the impact and vibration on the pipeline and other equipment, prolong the service life of the entire system, and also help to improve the working efficiency of the pump.

[0077] Further, it further includes a base 3 which is detachably arranged at the bottom of the shell 1.

[0078] In the above scheme, the base 3 improves the installation convenience and stability of the pump. The detachable connection facilitates maintenance and repair of the pump, reduces maintenance cost and downtime, and improves production efficiency.

[0079] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A three-cylinder reciprocating pump characterized by, The utility model relates to a kind of hydraulic motor, including: Shell (1) with through hole (101); Hydraulic end assembly (2) is arranged on one side of the shell (1); Crank mechanism (5) is arranged on the shell (1), the crank mechanism (5) includes power input end and power output end; Driving shaft (4) is rotatably arranged on the shell (1), and the driving shaft (4) is drivingly connected with the power input end; Pull rod (11) is reciprocatingly slidably arranged in the shell (1), one end of the pull rod (11) is arranged on the power output end; Displacement member (6) is slidably arranged on the hydraulic end assembly (2) with one end penetrating through the hydraulic end assembly (2), and the other end of the displacement member (6) is arranged on the other end of the pull rod (11).

2. A three cylinder reciprocating pump as claimed in claim 1, wherein, The crank mechanism (5) includes: Crankshaft (50) is rotatably arranged on the shell (1), and the crankshaft (50) has a plurality of crank necks (51) and crank webs (52); Connecting rod (10) has a plurality of ends, and each end of the connecting rod (10) is rotatably arranged at one of the crank webs (52), and the other end of the connecting rod (10) is hingedly connected with one end of the pull rod (11); First gear (501) is arranged on the crankshaft (50), the first gear (501) is coaxially arranged with the two end faces of the crankshaft (50), and the first gear (501) is drivingly connected with the driving shaft (4).

3. A three cylinder reciprocating pump as claimed in claim 2, wherein, The driving shaft (4) is located obliquely above the crankshaft (50), and further includes: Second gear (401) is arranged on the driving shaft (4), the second gear (401) is engaged with the first gear (501), and the second gear (401) and the first gear (501) are both herringbone gears.

4. A three cylinder reciprocating pump as claimed in claim 3, wherein, The width of the first gear (501) ranges from 150 to 240 mm, the width of the second gear (401) ranges from 160 to 250 mm, and the transmission ratio of the first gear (501) and the second gear (401) ranges from 4.1:1 to 5:

1.

5. A three cylinder reciprocating pump as claimed in claim 2, wherein, The crank neck (51) is fixedly connected with the crank web (52), and the distance between the crank neck (51) and the rotation center of the crank web (52) is 80-90 mm.

6. A three cylinder reciprocating pump as claimed in claim 2, wherein, Further including: Guide plate (8) is arranged in the shell (1); Crosshead assembly (9) is slidably arranged on the guide plate (8), and the pull rod (11) is connected with the connecting rod (10) through the crosshead assembly (9); Sealing member (12) is arranged on the outer wall of the shell (1), the sealing member (12) is located at the through hole (101), and the pull rod (11) slides through the sealing member (12).

7. A three cylinder reciprocating pump as claimed in claim 6 wherein, The sealing member (12) includes: Sealing box (1201) is detachably arranged on the outer wall of the guide plate (8) away from the connecting rod (10); Bellows (7) is sleeved on the pull rod (11), one end of the bellows (7) is arranged on the sealing box (1201), and the other end of the bellows (7) is arranged on the end face of the pull rod (11) away from the sealing box (1201).

8. A three cylinder reciprocating pump according to claim 7, characterized in that The sealing box (1201) has an oil return groove, and the sealing box (1201) comprises: a box body; an oil seal ring (1202) arranged in the box body, the oil seal ring (1202) being sleeved on the pull rod (11); a plurality of skeleton oil seals (1203), each of the plurality of skeleton oil seals (1203) being arranged on the two sides of the oil seal ring (1202) a sealing ring (1204) arranged in a recessed portion inside the oil seal ring (1202); a fixing clamp (1205) arranged in the box body, and the fixing clamp (1205) being located outside the skeleton oil seal (1203) close to the bellows (7).

9. A three cylinder reciprocating pump as claimed in claim 1, wherein, Further comprising a safety valve assembly (201), an air pack assembly (202) and a discharge pipeline assembly (203), the safety valve assembly (201), the air pack assembly (202) and the discharge pipeline assembly (203) being arranged on the two sides of a fluid end assembly (2).

10. A three cylinder reciprocating pump as claimed in claim 1, wherein, Further comprising: a base (3) detachably arranged at the bottom of the shell (1).

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