Hydraulic diaphragm metering pump with pulseless constant flow output

Abstract

The hydraulic diaphragm metering pump comprises a pump head, a pump body and a motor, a transmission assembly is arranged in the pump body, the motor is used for driving the transmission assembly, and the transmission assembly comprises a driving shaft, a constant-speed cam, a first plunger assembly and a second plunger assembly. The first plunger assembly and the second plunger assembly are located on the two sides of the constant-speed cam respectively, the first plunger assembly is used for controlling the first diaphragm assembly, and the second plunger assembly is used for controlling the second diaphragm assembly. The constant-speed cam structure is optimally designed, reciprocating synchronous control over the first plunger assembly and the second plunger assembly is achieved, and in the reciprocating motion of the first plunger assembly and the second plunger assembly, a first diaphragm cavity and a second diaphragm cavity are in the discharging and sucking complementation state; medium flow in the first pump cavity and the second pump cavity is always in a complementary process, and medium flow transmission is always in a constant state.

Description

Technical Field

[0001] The invention relates to the technical field of metering pumps, and in particular to a hydraulic diaphragm metering pump with pulsation-free constant flow output. Background Art

[0002] As an ideal device for precise metering and dosing of fluids, metering pumps have been widely used in industries including pharmaceuticals, food, and petrochemicals. Since metering pumps work in a reciprocating motion mechanism, the suction and discharge processes of the liquid medium in the metering pump are carried out alternately, and the speed of the plunger is constantly changing during the displacement process, so the instantaneous flow of the metering pump not only changes with time, but also is output in a discontinuous pulsating form. For this reason, the pulsating output not only impacts the inner wall of the pipeline, causing the pipeline to vibrate and affect the metering effect, but is also more likely to cause corrosion to the inner wall of the pipeline, causing high-risk media to leak, posing a safety hazard.

[0003] Common low-pulsation pumps are formed by two (double-type) or three (triplet-type) reciprocating pumps. The reciprocating pump includes a reciprocating plunger, a pump chamber whose volume increases or decreases as the plunger advances and retreats (reciprocating motion), and a suction valve and a discharge valve connected to the pump chamber. When the plunger retreats (returns), the pump chamber is depressurized, and accordingly, the suction valve opens to introduce liquid into the pump chamber. When the plunger passes through the lower dead center and advances (goes forward), the pump chamber is pressurized to open the discharge valve, and the liquid is transported from the open discharge valve to the common discharge piping. As the driving device of each reciprocating pump, a motor, a camshaft, and an eccentric drive cam are provided. The plunger of the reciprocating pump is connected to the eccentric drive cam and advances and retreats with the rotation of the cam.

[0004] Combined with Figures 16 to 19 As shown, for the reciprocating pump commonly used in the prior art, its pulsation can be gradually reduced based on the reciprocating cross-compensation between the multi-stage pumps.

[0005] In the case of a double-connected reciprocating pump, the phase difference of the eccentric driving cam relative to each reciprocating pump is set to 180°, so that the discharge process of one reciprocating pump is carried out complementary to the discharge process of another reciprocating pump. For example, the announcement number is CN101644244A, and the patent name is a pulsation-free metering pump. The metering pump includes a motor, a pump head and a plunger, and its eccentric wheel is connected to the rotating shaft of the motor through a transmission mechanism; the eccentric wheel has an outer edge shape that conforms to the characteristics of the Archimedean curve; the metering pump has two pump heads and two plungers, and each plunger corresponds to a pump head; two slide rod assemblies are arranged opposite to each other on both sides of the side of the eccentric wheel, and the adjacent ends of the two slide rod assemblies each have a connecting rod that penetrates the slide rod assembly, and the two connecting rods are connected between their corresponding ends by a connecting bolt, and the ends of the two slide rod assemblies are close to the side of the eccentric wheel; the two slide rod assemblies are respectively connected to a plunger through a connecting piece.

[0006] The reciprocating pumps currently available on the market usually have the characteristics of large size, large flow, low pressure and low flow accuracy control, which makes them unable to meet the needs of metering pumps for high-precision and high-pressure conveying media. Summary of the invention

[0007] In view of the above problems, the present invention aims to provide a hydraulic diaphragm metering pump with pulsation-free constant flow output, which has the characteristics of higher precision and pulsation suppression.

[0008] The technical problem solved by the present invention can be achieved by adopting the following technical solutions: A hydraulic diaphragm metering pump with a pulsation-free constant flow output comprises a pump head, a pump body and a motor, wherein a transmission assembly is arranged in the pump body, and the motor is used to drive the transmission assembly, and the transmission assembly comprises a drive shaft, a constant velocity cam driven by the drive shaft, a first plunger assembly and a second plunger assembly used to cooperate with the constant velocity cam, wherein the first plunger assembly and the second plunger assembly are respectively located on both sides of the constant velocity cam, the first plunger assembly is used to control the first diaphragm assembly, and the second plunger assembly is used to control the second diaphragm assembly, and the first diaphragm assembly and the second diaphragm assembly are both arranged in the pump head, and the first plunger assembly and the second plunger assembly are driven by the constant velocity cam, and the suction and discharge control of the first diaphragm assembly by the first plunger assembly and the suction and discharge control of the second diaphragm assembly by the second plunger assembly form cross-complementarity with each other, so that the metering pump is always in a pulsation-free constant flow transmission.

[0009] A first cavity is provided in the pump body, the first cavity is used to cooperate with the first plunger assembly, the first cavity is communicated with the first diaphragm cavity in the pump head through the first flow channel portion, and the first diaphragm cavity is provided with a first diaphragm assembly; a second cavity is provided in the pump body, the second cavity is used to cooperate with the second plunger assembly, the second cavity is communicated with the second diaphragm cavity in the pump head through the second flow channel portion, and the second diaphragm cavity is provided with a second diaphragm assembly.

[0010] The first plunger assembly includes a first adjustment seat and a first plunger body installed in cooperation with the first adjustment seat, and the other end of the first plunger body extends into the first cavity; the second plunger assembly includes a second adjustment seat and a second plunger body installed in cooperation with the second adjustment seat, and the other end of the second plunger body extends into the second cavity; a reset base is also provided, and the reset base is located on one side of the first adjustment seat, and a plurality of guide rails are provided between the reset base and the second adjustment seat, and the first adjustment seat is used for sliding cooperation with the guide rails; after the first adjustment seat is driven by the constant velocity cam, it can move along the guide rail toward the reset base, and when the constant velocity cam and the first adjustment seat exceed the critical point of the conflict drive, the reset base drives the first adjustment seat to gradually complete the reset.

[0011] The reset base includes a base body and a reset spring arranged in the base body, one end of the reset spring abuts against the inner cavity wall of the base body, and the other end abuts against the first adjustment seat, and the first adjustment seat is provided with a first plunger assembly part, the reset spring is sleeved on the first plunger assembly part, and the first plunger assembly part is used to cooperate with one end of the first plunger body for installation.

[0012] When the constant velocity cam is in contact with the second adjustment seat, the second adjustment seat, the composite base and the first adjustment seat move toward the second cavity as a whole.

[0013] The constant speed cam can be divided into an accelerating discharge arc portion, a decelerating suction arc portion, a uniform suction arc portion, an accelerating suction arc portion, a decelerating discharge arc portion and a uniform discharge arc portion in sequence according to the circumferential surface.

[0014] The center angle of the uniform discharge arc is 135 degrees, and the center angles of the accelerated discharge arc, the decelerated suction arc, the uniform suction arc, the accelerated suction arc, and the decelerated discharge arc are all 45 degrees.

[0015] A common feed valve body, a common discharge valve body and a common pump head are provided on the pump head, and a first pump chamber and a second pump chamber are provided in the common pump head. The first pump chamber is used to cooperate with the first diaphragm assembly, and the second pump chamber is used to cooperate with the second diaphragm assembly.

[0016] The common feed valve body includes a common feed cavity, a first feed channel and a second feed channel. The first feed channel is connected to the first pump cavity through a first feed check valve, and the second feed channel is connected to the second pump cavity through a second feed check valve; the common discharge valve body includes a common discharge cavity, a first discharge channel and a second discharge channel. The first discharge channel is connected to the first pump cavity through a first discharge check valve, and the second discharge channel is connected to the second pump cavity through a second discharge check valve.

[0017] The first diaphragm assembly includes a first diaphragm and a first valve body, and the second diaphragm assembly includes a second diaphragm and a second valve body. The first valve body is arranged in the first diaphragm cavity. The first diaphragm is used to realize the suction and discharge effect on the first medium cavity. The second diaphragm is used to realize the suction and discharge effect on the second medium cavity. The first medium cavity is connected with the first pump cavity through the first medium flow channel, and the second medium cavity is connected with the second pump cavity through the second medium flow channel.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the present invention optimizes the design of the constant-speed cam structure, utilizes the constant-speed cam in combination with the first adjustment seat, the second adjustment seat and the reset base to achieve reciprocating synchronous control of the first plunger assembly and the second plunger assembly, so that during the reciprocating motion of the first plunger assembly and the second plunger assembly, the first diaphragm cavity and the second diaphragm cavity are in complementary suction and discharge, so that the medium flow in the first pump cavity and the second pump cavity is always in a complementary process, thereby achieving that the medium flow transmission is always in a constant state.

[0019] The features of the present invention can be clearly understood by referring to the drawings and the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall installation structure of the present invention is shown in FIG. Figure 1 ; Figure 2 The overall installation structure of the present invention is shown in FIG. Figure 2 ; Figure 3 It is a schematic diagram of the internal installation structure of the pump head and the pump body of the present invention; Figure 4 It is a schematic diagram of the internal installation structure of the pump body of the present invention; Figure 5 The overall cross-sectional structure of the present invention is schematically shown Figure 1 ; Figure 6 The overall cross-sectional structure of the present invention is schematically shown Figure 2 ; Figure 7 for Figure 6 The schematic diagram of the partial enlarged structure of the middle D part; Figure 8 The overall cross-sectional structure of the present invention is schematically shown Figure 3 ; Fig. 9 The overall cross-sectional structure of the present invention is schematically shown Figure 4 ; Fig.10 It is a schematic diagram of the cross-sectional structure of the pump head of the present invention; Fig.11 The pump head installation structure of the present invention is schematically shown in FIG. Figure 1 ; Fig.12 The pump head installation structure of the present invention is schematically shown in FIG. Figure 2 ; Fig.13 It is a schematic diagram of the instantaneous flow curve of the present invention; Fig.14 The constant speed cam structure of the present invention is shown in FIG. Figure 1 ; Fig.15The constant speed cam structure of the present invention is shown in FIG. Figure 2 ; Fig.16 It is a schematic diagram of the instantaneous flow curve of a conventional single-head reciprocating pump in the prior art; Fig.17 It is a schematic diagram of the instantaneous flow curve of a conventional double-head reciprocating pump in the prior art; Fig.18 It is a schematic diagram of the instantaneous flow curve of a conventional three-head reciprocating pump in the prior art; Fig.19 It is a schematic diagram of the instantaneous flow curve of a conventional five-head reciprocating pump in the prior art. DETAILED DESCRIPTION

[0021] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below with reference to specific diagrams.

[0022] In the description of the present invention, it is necessary to understand that the terms "one end", "the other end", "outside", "upper", "inside", "horizontal", "coaxial", "center", "end", "length", "outer end" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] Combined with Figures 1 to 19 As shown, this embodiment discloses a hydraulic diaphragm metering pump with a pulsation-free constant flow output, including a pump head 300, a pump body 200 and a motor 100. A transmission assembly is arranged in the pump body 200, the motor 100 is used to drive the transmission assembly, and the pump head 300 is used to realize the transmission of the medium flow.

[0024] Among them, the transmission assembly includes a drive shaft 410, a constant velocity cam 400 driven by the drive shaft 410, a first plunger assembly 500 and a second plunger assembly 600 for cooperating with the constant velocity cam 400, wherein the other end of the drive shaft 410 is usually matched with a transmission gear 420, and the transmission gear 420 is used to cooperate with the gear ring part in the input shaft 110, wherein the transmission gear 420 is independently set, which can increase the accuracy of the transmission gear 420, and combined with the power output of the input shaft 110, increase the transmission stability of the constant velocity cam 400, and the input shaft 110 is usually used to cooperate with the motor 100.

[0025] In combination with the above, the first plunger assembly 500 and the second plunger assembly 600 are respectively located on both sides of the constant velocity cam 400, and the constant velocity cam 400 is used to drive the first plunger assembly 500 and the second plunger assembly 600; Fig.15 and Fig.16As shown, the structure of the constant velocity cam 400 is optimized. The constant velocity cam 400 can be divided into an accelerating discharge arc portion 401, a decelerating material suction arc portion 402, a uniform material suction arc portion 403, an accelerating material suction arc portion 404, a decelerating material discharge arc portion 405 and a uniform material discharge arc portion 406 in sequence according to the circumferential surface. The center angle of the uniform material discharge arc portion 406 is 135 degrees, and the center angles of the accelerating discharge arc portion 401, the decelerating material suction arc portion 402, the uniform material suction arc portion 403, the accelerating material suction arc portion 404 and the decelerating material discharge arc portion 405 are all 45 degrees. Fig.13 As shown, the instantaneous flow curve of the pulsation-free pump is displayed correspondingly. The constant velocity cam 400 is used to realize the cooperation with the first plunger assembly 500 and the second plunger assembly 600 in the reciprocating motion, and they can complement each other. For example, when the accelerating discharge arc portion 401 in the constant velocity cam 400 is in conflict with the first plunger assembly 500, the accelerated discharge is realized in the first pump chamber 350. Synchronously, the decelerating discharge arc portion 405 in the constant velocity cam 400 is in conflict with the second plunger assembly 600, so that the decelerated discharge is realized in the second pump chamber 360, and so on, so that the metering pump as a whole is always at a constant flow rate.

[0026] Combined with Fig.13 As shown, the first plunger assembly 500 combines with the first diaphragm assembly 330 to realize the corresponding instantaneous flow curve A for the first pump chamber 350, and the second plunger assembly 600 combines with the second diaphragm assembly 360 to complete the corresponding instantaneous flow curve B. The two can realize cross-complementarity in the discharging process and the suction process respectively, and form an instantaneous flow synthesis curve C after cross-complementarity; when the instantaneous flow curve B enters the uniform discharging or suction state, at the same time the instantaneous flow curve A enters the inactive state, that is, the corresponding feed check valve or discharge check valve is in a closed state, so that a single pump chamber in the first pump chamber 350 or the second pump chamber 360 can realize uniform discharging or suction.

[0027] In the specific structure, the first plunger assembly 500 is used to control the first diaphragm assembly 330, and the second plunger assembly 600 is used to control the second diaphragm assembly 340. The first diaphragm assembly 330 and the second diaphragm assembly 340 are both arranged in the pump head 300. The pump head 300 adopts an integrated structural design to optimize the overall structure, so that the metering pump as a whole is more optimized, which is convenient for achieving high-pressure delivery and high-precision delivery; the first plunger assembly 500 and the second plunger assembly 600 are driven by the constant velocity cam 400, and the suction and discharge control of the first diaphragm assembly 330 by the first plunger assembly 500 and the suction and discharge control of the second diaphragm assembly 340 by the second plunger assembly 600 form cross-complementarity with each other, so that the metering pump is always in a pulsation-free constant flow transmission.

[0028] The pump body 200 is provided with a first cavity 201, the first cavity 201 is used to cooperate with the first plunger assembly 500, the first cavity 201 is connected to the first diaphragm cavity 301 in the pump head 200 through the first flow channel portion 210, and the first diaphragm assembly 330 is arranged in the first diaphragm cavity 301; the pump 200 is provided with a second cavity 202, the second cavity 202 is used to cooperate with the second plunger assembly 600, the second cavity 202 is connected to the pump head 300 through the second flow channel portion 220 The second diaphragm cavity 302 is connected, and a second diaphragm assembly 340 is arranged in the second diaphragm cavity 302; wherein, the first cavity 201, the first flow channel portion 210, and the first diaphragm cavity 301 are connected to each other and are all used to fill hydraulic oil, and the second cavity 202, the second flow channel portion 220, and the second diaphragm cavity 302 are connected to each other and are all used to fill hydraulic oil; wherein, the first flow channel portion 210 and the second flow channel portion 220 are respectively provided with the first flow channel and the second flow channel inside, so as to facilitate the circulation of hydraulic oil.

[0029] In combination with the above, the first plunger assembly 500 includes a first adjustment seat 510 and a first plunger body 520 installed in cooperation with the first adjustment seat 510, and the other end of the first plunger body 520 extends into the first cavity 201; the second plunger assembly 600 includes a second adjustment seat 610 and a second plunger body 620 installed in cooperation with the second adjustment seat 610, and the other end of the second plunger body 620 extends into the second cavity 202; a reset base 700 is also provided, and the reset base 700 is located on one side of the first adjustment seat 510, and the reset base A plurality of guide rails 730 are arranged between 700 and the second adjustment seat 610. In a specific embodiment, the number of the guide rails 730 can be 4, which are arranged at four corners respectively, and the first adjustment seat 510 is used to slide with the guide rails 730; after the first adjustment seat 510 is driven by the constant velocity cam 400, it can move along the guide rails 730 toward the reset base 700. When the constant velocity cam 400 and the first adjustment seat 510 exceed the critical point of the conflict, the reset base 700 drives the first adjustment seat 510 to gradually complete the reset.

[0030] The structures of the first adjustment seat 510, the second adjustment seat 610 and the reset base 700 are optimized in design, and the constant velocity cam 400 is used to realize resistance driving on the first adjustment seat 510, so that the first adjustment seat 510 can complete the pushing of the first plunger body 520. The structural design that the first adjustment seat 510 can move along the guide rail 730 is utilized, and the second adjustment seat 610 and the reset base 700 are in a synchronous state as a whole. Therefore, the first adjustment seat 510 can be moved relative to the second adjustment seat 610 and the reset base 700. Combined with the corresponding structure of the constant velocity cam 400, it can achieve good cross-complementarity.

[0031] In the specific structure, the reset base 700 includes a base body 710 and a reset spring 720 arranged in the base body 710, one end of the reset spring 720 abuts against the inner cavity wall of the base body 710, and the other end abuts against the first adjustment seat 510, and the first adjustment seat 510 is provided with a first plunger assembly portion 511, and the reset spring 720 is sleeved on the first plunger assembly portion 511, and the first plunger assembly portion 511 is used to cooperate with one end of the first plunger body 520 for installation; when the constant velocity cam 400 abuts against the second adjustment seat 610, the second adjustment seat 610, the reset base 700 and the first adjustment seat 510 move as a whole toward the second cavity 202; wherein, the second adjustment seat 610 is usually provided with a second plunger assembly portion 611, and the second plunger assembly portion 611 is used to cooperate with one end of the second plunger body 620 for installation.

[0032] In combination with the above, the pump head 300 is equipped with a common feed valve body 310, a common discharge valve body 320 and a common pump head 301. The common feed valve body 310 is used to complete the suction of the medium, and the common discharge valve body 320 is used to complete the discharge of the medium. Usually, the flow channel cavity in the common feed valve body 310 is larger than the flow channel cavity in the common discharge valve body 320; the common pump head 301 is provided with a first pump cavity 350 and a second pump cavity 360, the first pump cavity 350 and the second pump cavity 360 are independent of each other, the first pump cavity 350 is used to cooperate with the first diaphragm assembly 330, and the second pump cavity 360 is used to cooperate with the second diaphragm assembly 340; the common feed valve body 310 includes a common feed cavity 311, a first feed flow channel 312 and a second feed The flow channel 313, the ends of the first feed flow channel 312 and the second feed flow channel 313 are all connected to the common feed cavity 311, the first feed flow channel 312 is connected to the first pump cavity 350 through the first feed check valve 314, and the second feed flow channel 313 is connected to the second pump cavity 360 through the second feed check valve 315; the common discharge valve body 320 includes a common discharge cavity 321, a first discharge flow channel 322 and a second discharge flow channel 323, the ends of the first discharge flow channel 322 and the second discharge flow channel 323 are all connected to the common discharge cavity 321, the first discharge flow channel 322 is connected to the first pump cavity 350 through the first discharge check valve 324, and the second discharge flow channel 323 is connected to the second pump cavity 360 through the second discharge check valve 325.

[0033] Among them, this embodiment optimizes the design of the pump head 300 structure, and utilizes the design of a common feed valve body 310, a common discharge valve body 320 and a common pump head 301, so as to shorten the pipeline return space, reduce the influence of fluid inertia on pulsation, and reduce the influence of fluid compressibility on pulsation at high pressure.

[0034] In combination with the above, the first diaphragm assembly 330 includes a first diaphragm 332 and a first valve body 331, the second diaphragm assembly 340 includes a second diaphragm 342 and a second valve body 341, the first valve body 331 is arranged in the first diaphragm cavity 301, the first diaphragm 332 is used to realize the suction and discharge effect on the first medium cavity 351, the second diaphragm 342 is used to realize the suction and discharge effect on the second medium cavity 361, the first medium cavity 351 is connected with the first pump cavity 350 through the first medium flow channel 352, and the second medium cavity 361 is connected with the second medium cavity 361 through the second medium flow channel 352. The channel 362 is connected with the second pump chamber 360; the optimized design utilizes the complementary suction and discharge effects between the first diaphragm 332 and the second diaphragm 342, and combines with the corresponding instantaneous flow curve, so that when the pump head 300 is feeding, the total amount of feed of the first feed channel 210 and the second feed channel 220 is always kept at the same flow rate; when discharging, in combination with the shared discharge valve body, the first discharge channel 210 and the second discharge channel 220 are utilized, so that the total amount of discharge is always at the same flow rate, thereby realizing the constant flow transmission of the metering pump.

[0035] The present invention optimizes the design of the constant-velocity cam structure and utilizes the constant-velocity cam in combination with the first adjustment seat, the second adjustment seat and the reset base to achieve reciprocating synchronous control of the first plunger assembly and the second plunger assembly, so that during the reciprocating motion of the first plunger assembly and the second plunger assembly, the first diaphragm cavity and the second diaphragm cavity are in a complementary suction and discharge state, so that the medium flow in the first pump cavity and the second pump cavity is always in a complementary process, thereby achieving that the medium flow transmission is always in a constant state.

[0036] The above description is only a preferred embodiment of the present invention and does not impose any form of limitation on the invention. Any simple modification, equivalent change or modification made to the above embodiments based on the technical principle of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A hydraulic diaphragm metering pump with a pulsation-free constant flow output, comprising a pump head, a pump body and a motor, wherein a transmission assembly is arranged in the pump body, and the motor is used to drive the transmission assembly, characterized in that: The transmission assembly includes a driving shaft, a constant velocity cam driven by the driving shaft, a first plunger assembly and a second plunger assembly for cooperating with the constant velocity cam, the first plunger assembly and the second plunger assembly are respectively located on both sides of the constant velocity cam, the first plunger assembly is used to control the first diaphragm assembly, the second plunger assembly is used to control the second diaphragm assembly, the first diaphragm assembly and the second diaphragm assembly are both arranged in the pump head, and the first plunger assembly and the second plunger assembly are driven by the constant velocity cam, and the suction and discharge control of the first diaphragm assembly by the first plunger assembly and the suction and discharge control of the second diaphragm assembly by the second plunger assembly form cross-complementarity with each other, so that the metering pump is always in a pulsation-free constant flow transmission.

2. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 1, characterized in that: A first cavity is provided in the pump body, the first cavity is used to cooperate with the first plunger assembly, the first cavity is communicated with the first diaphragm cavity in the pump head through the first flow channel portion, and the first diaphragm cavity is provided with a first diaphragm assembly; a second cavity is provided in the pump body, the second cavity is used to cooperate with the second plunger assembly, the second cavity is communicated with the second diaphragm cavity in the pump head through the second flow channel portion, and the second diaphragm cavity is provided with a second diaphragm assembly.

3. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 2, characterized in that: The first plunger assembly includes a first adjustment seat and a first plunger body installed in cooperation with the first adjustment seat, and the other end of the first plunger body extends into the first cavity; the second plunger assembly includes a second adjustment seat and a second plunger body installed in cooperation with the second adjustment seat, and the other end of the second plunger body extends into the second cavity; a reset base is also provided, and the reset base is located on one side of the first adjustment seat, and a plurality of guide rails are provided between the reset base and the second adjustment seat, and the first adjustment seat is used for sliding cooperation with the guide rails; after the first adjustment seat is driven by the constant velocity cam, it can move along the guide rail toward the reset base, and when the constant velocity cam and the first adjustment seat exceed the critical point of the conflict drive, the reset base drives the first adjustment seat to gradually complete the reset.

4. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 3, characterized in that: The reset base includes a base body and a reset spring arranged in the base body, one end of the reset spring abuts against the inner cavity wall of the base body, and the other end abuts against the first adjustment seat, and the first adjustment seat is provided with a first plunger assembly part, the reset spring is sleeved on the first plunger assembly part, and the first plunger assembly part is used to cooperate with one end of the first plunger body for installation.

5. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 4, characterized in that: When the constant velocity cam is in contact with the second adjustment seat, the second adjustment seat, the composite base and the first adjustment seat move toward the second cavity as a whole.

6. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 5, characterized in that: The constant speed cam can be divided into an accelerating discharge arc portion, a decelerating suction arc portion, a uniform suction arc portion, an accelerating suction arc portion, a decelerating discharge arc portion and a uniform discharge arc portion in sequence according to the circumferential surface.

7. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 6, characterized in that: The center angle of the uniform discharge arc is 135 degrees, and the center angles of the accelerated discharge arc, the decelerated suction arc, the uniform suction arc, the accelerated suction arc, and the decelerated discharge arc are all 45 degrees.

8. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to any one of claims 1 to 7, characterized in that: A common feed valve body, a common discharge valve body and a common pump head are provided on the pump head, and a first pump chamber and a second pump chamber are provided in the common pump head. The first pump chamber is used to cooperate with the first diaphragm assembly, and the second pump chamber is used to cooperate with the second diaphragm assembly.

9. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 8, characterized in that: The common feed valve body includes a common feed cavity, a first feed channel and a second feed channel. The first feed channel is connected to the first pump cavity through a first feed check valve, and the second feed channel is connected to the second pump cavity through a second feed check valve; the common discharge valve body includes a common discharge cavity, a first discharge channel and a second discharge channel. The first discharge channel is connected to the first pump cavity through a first discharge check valve, and the second discharge channel is connected to the second pump cavity through a second discharge check valve.

10. A hydraulic diaphragm metering pump with pulsation-free constant flow output according to claim 9, characterized in that: The first diaphragm assembly includes a first diaphragm and a first valve body, and the second diaphragm assembly includes a second diaphragm and a second valve body. The first valve body is arranged in the first diaphragm cavity. The first diaphragm is used to realize the suction and discharge effect on the first medium cavity. The second diaphragm is used to realize the suction and discharge effect on the second medium cavity. The first medium cavity is connected with the first pump cavity through the first medium flow channel, and the second medium cavity is connected with the second pump cavity through the second medium flow channel.

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