Pump head structure and liquid chromatography pump

Abstract

The utility model discloses a pump head structure and liquid chromatograph pump, wherein, pump head structure includes pump head upper end cover, pump head shell, pump head lower end cover, at least two inlet check valve subassembly and at least two outlet check valve subassembly, be equipped with the upper end cover internal pipeline in the pump head upper end cover, and the first connecting pipeline communication has between the upper end cover internal pipeline and outlet check valve subassembly, be equipped with the second connecting pipeline in the pump head shell, and the one side of second connecting pipeline is equipped with the plunger rod action pipeline for the plunger rod insertion, and second connecting pipeline links to each other with outlet check valve subassembly and inlet check valve subassembly, be equipped with the lower end cover internal pipeline in the pump head lower end cover, and the third connecting pipeline communication has between the lower end cover internal pipeline and inlet check valve subassembly, the utility model discloses under the prerequisite of guaranteeing necessary flow path, cancelled the pipeline and pipeline joint between the rest of adjacent structure, greatly reduced the delay volume of mobile phase, improved the analysis efficiency, and prevented the diffusion of sample.

Description

Technical Field

[0001] This utility model relates to the field of infusion pump technology, specifically to a pump head structure and a liquid chromatography pump. Background Technology

[0002] With the development of science and technology and the progress of society, the requirements for the analytical accuracy, repeatability and stability of liquid chromatographs are becoming increasingly stringent. The liquid chromatography pump is one of the important components of a liquid chromatograph, and its performance directly affects the analytical results. As the core component of the liquid chromatography pump, the length of its flow path has a significant impact on liquid chromatography analysis.

[0003] Currently, the commonly used liquid chromatography pump is the quaternary low-pressure mixed liquid chromatography pump system. In the quaternary low-pressure mixed liquid chromatography pump system, the organic solvent phase must be fully mixed in the liquid chromatography method required to achieve chromatographic separation of target compounds in the chromatographic column flow channel in order to promote the chromatographic separation of different target compounds in the sample in the chromatographic column due to the chromatographic retention time differences.

[0004] However, existing quaternary low-pressure mixed liquid chromatography pump systems have a large number of pipes and pipe joints. The flow path volume of the mixed organic phase with different flow rates from the quaternary gradient proportional valve to the chromatographic column is called the delay volume (the fluid volume before the required mixed mobile phase). The longer the pipe, the larger the delay volume, which will lead to lower efficiency of liquid chromatography analysis of the sample. At the same time, sample diffusion problems will also occur, which will seriously affect the analysis results.

[0005] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a pump head structure and a liquid chromatography pump, which aims to solve the technical problems of low efficiency of liquid chromatography analysis of samples and sample diffusion caused by the large delay volume of the mixed mobile phase by simplifying the pipeline and connection relationship.

[0007] The technical solution adopted by this utility model to solve the technical problem is as follows:

[0008] A pump head structure includes a pump head upper cover, a pump head housing, a pump head lower cover, at least two inlet check valve assemblies, and at least two outlet check valve assemblies; The pump head upper cover is provided with an internal pipe, and the internal pipe of the upper cover is connected to the outlet one-way valve assembly by a first connecting pipe. The pump head housing is provided with a second connecting pipe, and a plunger rod actuation pipe for plunger rod insertion is provided on one side of the second connecting pipe. The second connecting pipe is connected to the outlet check valve assembly and the inlet check valve assembly. The pump head has an internal pipe inside the lower end cover, and a third connecting pipe connects the internal pipe inside the lower end cover to the inlet check valve assembly.

[0009] As a further improvement to the technical solution, a manual venting valve is provided on one side of the upper cover of the pump head.

[0010] As a further improved technical solution, the pump head upper cover includes an upper cover housing and a pressure sensor, with the pressure sensor disposed inside the upper cover housing.

[0011] As a further improvement to the technical solution, a mixer is also provided inside the upper end cover housing, which is arranged separately from the pressure sensor.

[0012] As a further improvement, the pump head housing is provided with at least two spaced plunger rod working chamber bushings for connecting to one end of the plunger rod.

[0013] As a further improved technical solution, the inlet check valve assembly includes a check valve connecting sealing ring and at least two first mounting sleeves; Both ends of the one-way valve connecting sealing ring are provided with the first mounting sleeve; the end of the first mounting sleeve away from the one-way valve connecting sealing ring is provided with the first one-way valve outlet sealing ring; a first ball seat is provided between the first mounting sleeve and the one-way valve connecting sealing ring, and a first one-way valve ball is provided on the first ball seat.

[0014] As a further improved technical solution, the outlet check valve assembly includes a second mounting sleeve and at least two second check valve outlet sealing rings; The second mounting sleeve is provided with a second one-way valve outlet sealing ring at both ends, and a guide pin, a second ball seat, and a second filter screen mounting gasket are provided inside the second mounting sleeve; An elastic reset element is sleeved on the guide pin, and one end of the elastic reset element abuts against the second mounting sleeve; The second ball seat is located on one side of the guide pin, and a second one-way valve ball is provided on the side of the second ball seat near the guide pin; The second filter screen mounting gasket is located between the second ball seat and one of the second one-way valve outlet sealing rings.

[0015] As a further improvement to the technical solution, a cleaning seat is provided on one side of the pump head housing, and at least two sets of spaced sealing ring assemblies are provided on the cleaning seat.

[0016] As a further improved technical solution, the sealing ring assembly includes a first sealing ring, a second sealing ring, and a third sealing ring; The first sealing ring is disposed on the cleaning seat, the first sealing ring is provided with the second sealing ring, the second sealing ring is sleeved with the second sealing ring, and the side of the second sealing ring sleeve opposite to the second sealing ring is sleeved with the third sealing ring.

[0017] Technical Solution 2: A liquid chromatography pump, including the pump head structure described in Technical Solution 1.

[0018] Compared with the prior art, the beneficial effects of this utility model are: This invention provides a pump head structure that, while ensuring the necessary flow path, eliminates the pipes and pipe joints between adjacent structures, thereby significantly reducing the delayed volume of the mobile phase, greatly improving the accuracy of liquid chromatography analysis results, increasing analytical efficiency, and preventing sample diffusion. At the same time, the highly integrated pump head structure is small in size and compact in structure, reducing the space occupied. Attached Figure Description

[0019] Figure 1 This is a top view of the pump head structure; Figure 2 for Figure 1 A schematic diagram of the AA section; Figure 3 for Figure 2 BB cross-section diagram; Figure 4 for Figure 2 CC section diagram; Figure 5 This is a schematic diagram of the first type of pump head structure; Figure 6 This is an assembly diagram of the first type of pump head structure; Figure 7 This is a schematic diagram of the upper cover of the pump head for the first type of pump head structure. Figure 8 This is a schematic diagram of the assembly of the upper cover of the pump head for the first type of pump head structure; Figure 9 This is a schematic diagram of the second type of pump head structure; Figure 10 This is a schematic diagram of the upper cover of the pump head for the second type of pump head structure. Figure 11 This is a schematic diagram of the assembly of the upper cover of the pump head for the second type of pump head structure. Figure 12 This is a schematic diagram of the pump head housing assembly. Figure 13 This is a schematic diagram of the inlet check valve assembly. Figure 14 This is a longitudinal sectional view of the inlet check valve assembly; Figure 15 This is a schematic diagram of the assembly of the inlet check valve assembly; Figure 16 This is a schematic diagram of the outlet check valve assembly. Figure 17 This is a longitudinal sectional view of the outlet check valve assembly; Figure 18 This is a schematic diagram of the assembly of the outlet check valve assembly; Figure 19 This is a schematic diagram of the structure of the first type of liquid chromatography pump; Figure 20 This is a schematic diagram of the second type of liquid chromatography pump.

[0020] The numbers in the diagram represent: 1. Cleaning seat; 1.1. First sealing ring; 1.2. Second sealing ring; 1.3. Second sealing ring bushing; 1.4. Third sealing ring; 2. Pump head assembly; 2.1. Pump head upper cover; 2.1.1. Manual vent valve; 2.1.2. Pressure sensor sealing gasket; 2.1.3. Pressure sensor; 2.1.4. Pressure sensor locking nut; 2.1.5. Mixer inlet filter; 2.1.6. 2.1.7 First filter screen sealing gasket; 2.1.8 Mixer sealing end cap; 2.1.9 Mixing flow channel column; 2.1.10 Mixer outlet gasket; 2.1.11 Mixer outlet nut; 2.1.12 First fastening screw; 2.1.13 Upper end cap housing; 2.1.14 Upper end cap internal piping; 2.1.15 First connecting pipe; 2.2 Inlet check valve assembly; 2.2.1 The first... 2.2.1 First mounting sleeve; 2.2.2 First check valve ball; 2.2.3 First ball seat; 2.2.4 Check valve connecting seal; 2.2.5 Check valve connecting seal; 2.3 Pump head housing; 2.3.1 Piston rod working chamber bushing; 2.3.2 Second fastening screw; 2.3.3 Piston rod actuation pipeline; 2.3.4 Second connecting pipeline; 2.4 Pump head lower end cover; 2.4.1 Lower end cover sealing screw; 2.4. 2. Third fastening screw; 2.4.3. Internal piping of lower end cover; 2.4.4. Third connecting pipe; 2.5. Outlet check valve assembly; 2.5.1. Second check valve outlet sealing ring; 2.5.2. Second mounting sleeve; 2.5.3. Elastic reset element; 2.5.4. Guide pin; 2.5.5. Second check valve ball; 2.5.6. Second ball seat; 2.5.7. Second filter screen mounting gasket; 2.5.8. Outlet check valve filter screen. Detailed Implementation

[0021] To make the objectives, technical solutions, and effects of this utility model clearer and more explicit, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0022] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component. Example 1

[0023] like Figures 1 to 6 As shown, where, Figure 1 This is a top view of the pump head structure; Figure 2 for Figure 1 A schematic diagram of the AA section; Figure 3 for Figure 2 BB cross-section diagram; Figure 4 for Figure 2 CC section diagram; Figure 5 This is a schematic diagram of the first type of pump head structure; Figure 6 This is an assembly diagram of the first type of pump head structure. Specifically, this embodiment provides a pump head structure, including a pump head upper cover 2.1, a pump head housing 2.3, a pump head lower cover 2.4, two inlet check valve assemblies 2.2, and two outlet check valve assemblies 2.5. The pump head upper cover 2.1 has an internal pipe 2.1.14, and a first connecting pipe 2.1.15 connects the internal pipe 2.1.14 to the outlet check valve assembly 2.5. That is, one end of the first connecting pipe 2.1.15 is connected to the internal pipe 2.1.14, and the other end is connected to the output port of the outlet check valve assembly 2.5. The pump head housing 2.3 has a second connecting pipe 2.3.4, and a supply column is provided on one side of the second connecting pipe 2.3.4. The plunger rod insertion is connected to the plunger rod actuation pipeline 2.3.3. The second connecting pipeline 2.3.4 is connected to the outlet check valve assembly 2.5 and the inlet check valve assembly 2.2. That is, one end of the second connecting pipeline 2.3.4 is connected to the inlet port of the outlet check valve assembly 2.5, and the other end is connected to the outlet port of the inlet check valve assembly 2.2. The pump head lower end cover 2.4 is provided with an internal pipeline 2.4.3. The internal pipeline 2.4.3 is connected to the inlet check valve assembly 2.2 by a third connecting pipeline 2.4.4. That is, one end of the third connecting pipeline 2.4.4 is connected to the internal pipeline 2.4.3, and the other end is connected to the inlet check valve assembly 2.2.

[0024] It should be noted that the mobile phase flows in from the internal pipe 2.4.3 of the lower end cover of the pump head 2.4, and sequentially passes through the third connecting pipe 2.4.4, the inlet check valve assembly 2.2, the second connecting pipe 2.3.4, the outlet check valve assembly 2.5, and the first connecting pipe 2.1.15 before converging into the internal pipe 2.1.14 of the upper end cover of the pump head 2.1. When the mobile phase passes through the plunger rod actuation pipe 2.3.3, a portion of the mobile phase enters the plunger rod actuation pipe 2.3.3, and the two plunger rods, one extending forward and the other retracting, perform alternating reciprocating motion. The structure of the plunger rod and related components is prior art and will not be described further here.

[0025] The pump head structure provided in this embodiment eliminates the pipes and pipe joints between adjacent structures while ensuring the necessary flow path. This significantly reduces the delay volume of the mobile phase. The smaller the delay volume, the shorter the chromatographic peak elution time of the target compound, the higher the peak height, and the better the peak symmetry. This greatly improves the accuracy of liquid chromatography analysis results and enhances analytical efficiency, while also preventing sample diffusion. At the same time, the highly integrated pump head structure is small and compact, thus occupying less space.

[0026] A cleaning seat 1 is provided on one side of the pump head housing 2.3. The pump head upper cover 2.1 and the pump head housing 2.3 are fixedly connected by a first fastening screw 2.1.12; the pump head housing 2.3 and the cleaning seat 1 are fixedly connected by a second fastening screw 2.3.2; and the pump head housing 2.3 and the pump head lower cover 2.4 are fixedly connected by a third fastening screw 2.4.2.

[0027] like Figure 7 and Figure 8 As shown, Figure 7 This is a schematic diagram of the upper cover of the pump head for the first type of pump head structure. Figure 8This is a schematic diagram of the assembly of the pump head upper cover for the first type of pump head structure. The pump head upper cover 2.1 provided in this embodiment only integrates the encapsulation of the pressure sensor 2.1.3, and is used in a binary high-pressure mixing infusion pump or a ternary high-pressure mixing infusion pump. The pump head upper cover 2.1 includes an upper cover housing 2.1.13, a manual vent valve 2.1.1, a pressure sensor sealing gasket 2.1.2, a pressure sensor 2.1.3, and a pressure sensor locking nut 2.1.4. The manual vent valve 2.1.1 is threaded to one side of the upper cover housing 2.1.13; the pressure sensor locking nut 2.1.4 is threaded to the other side of the upper cover housing 2.1.13; both the pressure sensor sealing gasket 2.1.2 and the pressure sensor 2.1.3 are disposed within the upper cover housing 2.1.13, and the pressure sensor 2.1.3 is located between the pressure sensor sealing gasket 2.1.2 and the pressure sensor locking nut 2.1.4.

[0028] like Figure 12 As shown, Figure 12 This is a schematic diagram of the pump head housing assembly. The pump head housing 2.3 is provided with two spaced-apart plunger rod working chamber bushings 2.3.1 for connecting to one end of the plunger rod. It should be noted that, among the two plunger rods, while one plunger rod is drawing in liquid, the other plunger rod is discharging liquid.

[0029] like Figures 13 to 15 As shown, where, Figure 13 This is a schematic diagram of the inlet check valve assembly. Figure 14 This is a longitudinal sectional view of the inlet check valve assembly; Figure 15 This is a schematic diagram of the inlet check valve assembly. Specifically, the inlet check valve assembly 2.2 is used for liquid aspiration. The inlet check valve assembly 2.2 includes a check valve connecting sealing ring 2.2.5 and two first mounting sleeves 2.2.2. Both ends of the check valve connecting sealing ring 2.2.5 are provided with the first mounting sleeves 2.2.2. The end of the first mounting sleeve 2.2.2 away from the check valve connecting sealing ring 2.2.5 is provided with a first check valve outlet sealing ring 2.2.1. A first ball seat 2.2.4 is provided between the first mounting sleeve 2.2.2 and the check valve connecting sealing ring 2.2.5, and a first check valve ball 2.2.3 is provided on the first ball seat 2.2.4.

[0030] It should be noted that the inlet check valve assembly 2.2 is provided with two first ball seats 2.2.4, and each of the two first ball seats 2.2.4 is provided with a first check valve ball 2.2.3, which increases the fault tolerance mechanism. This allows for a lower requirement for valve closing time. Since the presence of the elastic reset element increases the liquid suction resistance, the elastic reset element is omitted from the inlet check valve assembly 2.2.

[0031] like Figures 16 to 18 As shown, where, Figure 16 This is a schematic diagram of the outlet check valve assembly. Figure 17 This is a longitudinal sectional view of the outlet check valve assembly; Figure 18 This is a schematic diagram of the assembly of the outlet check valve assembly. It should be noted that the outlet check valve assembly 2.5 is used for liquid propulsion. The outlet check valve assembly 2.5 includes a second mounting sleeve 2.5.2 and two second check valve outlet sealing rings 2.5.1. Specifically, the second mounting sleeve 2.5.2 has a second check valve outlet sealing ring 2.5.1 at both ends. The second mounting sleeve 2.5.2 contains a guide pin 2.5.4, a second ball seat 2.5.6, and a second filter screen mounting washer 2.5.7. An elastic reset element 2.5.3 is fitted onto the guide pin 2.5.4, and one end of the elastic reset element 2.5.3 abuts against the second mounting sleeve 2.5.2. The elastic reset element 2.5.3 is specifically a spring. Of course, it should be understood that, under the condition of meeting actual needs... The elastic reset member 2.5.3 can also be other elastic reset structures in the prior art, which are not limited in this embodiment; the second ball seat 2.5.6 is disposed on one side of the guide pin 2.5.4, and the second ball seat 2.5.6 is provided with a second one-way valve ball 2.5.5 on the side of the guide pin 2.5.4; the second filter screen mounting gasket 2.5.7 is disposed between the second ball seat 2.5.6 and one of the second one-way valve outlet sealing rings 2.5.1, and the outlet one-way valve filter screen 2.5.8 is disposed on the side of the second filter screen mounting gasket 2.5.7 near one of the second one-way valve outlet sealing rings 2.5.1 and is abutted by the second one-way valve outlet sealing ring 2.5.1.

[0032] It should be noted that the second mounting sleeve 2.5.2 is provided with the guide pin 2.5.4 and the second ball seat 2.5.6. The second ball seat 2.5.6 is provided with the second one-way valve ball 2.5.5 on the side near the guide pin 2.5.4. When the outlet one-way valve assembly 2.5 closes in the reverse direction, the elastic reset member 2.5.3 will provide axial reset force in time to ensure that the second one-way valve ball 2.5.5 quickly resets and seals. Since the second one-way valve ball 2.5.5 and the second ball seat 2.5.6 are separate, specifically, the elastic reset member 2.5.3 pushes the guide pin 2.5.4, and the guide pin 2.5.4 pushes the second one-way valve ball 2.5.5, so that the second one-way valve ball 2.5.5 resets into the groove of the second ball seat 2.5.6.

[0033] The guide pin 2.5.4 provides guidance for the elastic reset member 2.5.3 and has the function of filling volume, thereby reducing the delayed volume of the mobile phase.

[0034] In this embodiment, a cleaning seat 1 is provided on one side of the pump head housing 2.3, and the cleaning seat 1 is provided with two sets of spaced-apart sealing ring assemblies. For details, please refer to... Figure 6 The sealing ring assembly includes a first sealing ring 1.1, a second sealing ring 1.2, and a third sealing ring 1.4; the first sealing ring 1.1 is disposed on the cleaning seat 1, the second sealing ring 1.2 is disposed on the first sealing ring 1.1, a second sealing ring bushing 1.3 is sleeved on the surface of the second sealing ring 1.2, and the third sealing ring 1.4 is sleeved on the end of the second sealing ring bushing 1.3 away from the second sealing ring 1.2.

[0035] It should be noted that by replacing the plunger rods of different diameters, the inlet check valve assembly 2.2, the outlet check valve assembly 2.5, and the sealing ring assembly, it is possible to match infusion pumps with different flow requirements, thereby achieving low flow rate requirements of 0-5 mL / min and high flow rate requirements of 0-100 mL / min, demonstrating strong flexibility and compatibility.

[0036] Please continue to refer to Figure 6 The pump head lower end cover 2.4 is provided with a lower end cover sealing screw 2.4.1 on one side.

[0037] In this embodiment, the lower end cap sealing screw 2.4.1 is a lower end cap polyetheretherketone (PEEK) sealing screw; the plunger rod working chamber bushing 2.3.1 is a PEEK plunger rod working chamber bushing; the pressure sensor sealing gasket 2.1.2 is a PEEK pressure sensor sealing gasket; the first one-way valve outlet sealing ring 2.2.1 is a PEEK first one-way valve outlet sealing ring 2.2.1; the one-way valve connection sealing ring 2.2.5 is a PEEK one-way valve connection sealing ring 2.2.5; the second one-way valve outlet sealing ring 2.5.1 is a PEEK second one-way valve outlet sealing ring; and the second filter screen mounting gasket 2.5.7 is a PEEK second filter screen mounting gasket. The pump head upper cover 2.1, which contacts the mixed mobile phase, is a titanium alloy pump head upper cover; the first mounting sleeve 2.2.2 is a titanium alloy first mounting sleeve; the second mounting sleeve 2.5.2 is a titanium alloy second mounting sleeve; the guide pin 2.5.4 is a titanium alloy guide pin; and the outlet one-way valve filter 2.5.8 is a titanium alloy outlet one-way valve filter. This ensures that the entire flow channel of the pump head upper cover 2.1 is made of inert material.

[0038] Of course, it should be understood that the plunger rod working chamber bushing 2.3.1 can be made of other materials besides polyetheretherketone plunger rod working chamber bushing, such as titanium alloy plunger rod working chamber bushing. This embodiment does not limit the material as long as the actual needs are met.

[0039] In addition, to ensure that the entire flow channel of the pump head structure is made of inert material, the pump head structure can be a polyetheretherketone pump head structure or a titanium alloy pump head structure. Example 2

[0040] like Figures 1 to 4 , Figure 9 , Figure 10 and Figure 11 As shown, where, Figure 9 This is a schematic diagram of the second type of pump head structure; Figure 10 This is a schematic diagram of the upper cover of the pump head for the second type of pump head structure. Figure 11 This is a schematic diagram of the assembly of the pump head upper cover for the second type of pump head structure. Specifically, this embodiment provides a pump head structure. Compared with Embodiment 1, this embodiment differs in that it uses a different pump head upper cover 2.1 than that in Embodiment 1. The pump head upper cover 2.1 can integrate not only the encapsulation of the pressure sensor 2.1.3, but also the encapsulation of the mixer. The mixer includes a mixer sealing end cover 2.1.7, a mixing channel column 2.1.8, and a mixing channel column bushing 2.1.9. The mixing channel column 2.1.8 is disposed within the mixer sealing end cover 2.1.7 and the mixing channel column bushing 2.1.9. The mixer can be any existing mixer in the prior art.

[0041] The structure of the pump head upper cover 2.1 is described in detail below.

[0042] The pump head upper cover 2.1 includes an upper cover housing 2.1.13, a manual vent valve 2.1.1, a pressure sensor sealing gasket 2.1.2, a pressure sensor 2.1.3, and a pressure sensor locking nut 2.1.4. The manual vent valve 2.1.1 is threaded to one side of the upper cover housing 2.1.13; the pressure sensor locking nut 2.1.4 is threaded to the other side of the upper cover housing 2.1.13; the pressure sensor sealing gasket 2.1.2 and the pressure sensor 2.1.3 are both disposed inside the upper cover housing 2.1.13, and the pressure sensor 2.1.3 is located between the pressure sensor sealing gasket 2.1.2 and the pressure sensor locking nut 2.1.4.

[0043] The pump head upper cover 2.1 further includes a mixer inlet filter 2.1.5, a first filter encapsulation gasket 2.1.6, a mixer sealing end cover 2.1.7, a mixing channel column 2.1.8, a mixing channel column bushing 2.1.9, a mixer outlet gasket 2.1.10, and a mixer outlet nut 2.1.11. The mixer outlet nut 2.1.11 is threaded to the other side of the upper end cover housing 2.1.13, and the mixer outlet gasket 2.1.10 is disposed inside the mixer outlet nut 2.1.11. The mixer inlet filter 2.1.5, the first filter encapsulation gasket 2.1.6, the mixer sealing end cover 2.1.7, the mixing channel column 2.1.8, and the mixing channel column bushing 2.1.9 are all disposed within the upper end cover housing 2.1.13. The mixing channel column 2.1.8 is located within the... On one side of the mixer outlet gasket 2.1.10, the surface of the mixing channel column 2.1.8 is fitted with the mixing channel column bushing 2.1.9; the mixer sealing end cap 2.1.7 is located at the end of the mixing channel column 2.1.8 away from the mixer outlet gasket 2.1.10; the first filter screen encapsulation gasket 2.1.6 is located on the side of the mixer sealing end cap 2.1.7 away from the mixing channel column 2.1.8, and the mixer inlet filter screen 2.1.5 is disposed inside the first filter screen encapsulation gasket 2.1.6.

[0044] In this embodiment, the lower end cap sealing screw 2.4.1 is a lower end cap polyetheretherketone (PEEK) sealing screw; the plunger rod working chamber bushing 2.3.1 is a PEEK plunger rod working chamber bushing; the pressure sensor sealing gasket 2.1.2 is a PEEK pressure sensor sealing gasket; the first filter screen encapsulation gasket 2.1.6 is a PEEK first filter screen encapsulation gasket; the mixer sealing end cap 2.1.7 is a PEEK mixer sealing end cap; the mixing channel column 2.1.8 is a PEEK mixing channel column; and the mixing channel column bushing... Set 2.1.9 is a polyetheretherketone (PEEK) mixing channel column bushing; mixer outlet gasket 2.1.10 is a PEEK mixer outlet gasket; first one-way valve outlet sealing ring 2.2.1 is a PEEK first one-way valve outlet sealing ring 2.2.1; one-way valve connection sealing ring 2.2.5 is a PEEK one-way valve connection sealing ring 2.2.5; second one-way valve outlet sealing ring 2.5.1 is a PEEK second one-way valve outlet sealing ring; second filter screen mounting gasket 2.5.7 is a PEEK second filter screen mounting gasket. The pump head upper cover 2.1, which contacts the mixed mobile phase, is a titanium alloy pump head upper cover; the mixer inlet filter 2.1.5 is a titanium alloy mixer inlet filter; the first mounting sleeve 2.2.2 is a titanium alloy first mounting sleeve; the second mounting sleeve 2.5.2 is a titanium alloy second mounting sleeve; the guide pin 2.5.4 is a titanium alloy guide pin; and the outlet check valve filter 2.5.8 is a titanium alloy outlet check valve filter. This ensures that the entire flow channel of the pump head upper cover 2.1 is made of inert material.

[0045] Of course, it should be understood that the plunger rod working chamber bushing 2.3.1 can be made of other materials besides polyetheretherketone plunger rod working chamber bushing, such as titanium alloy plunger rod working chamber bushing. This embodiment does not limit the material as long as the actual needs are met.

[0046] In addition, to ensure that the entire flow channel of the pump head structure is made of inert material, the pump head structure can be a polyetheretherketone pump head structure or a titanium alloy pump head structure.

[0047] The other structures in this embodiment are the same as in Embodiment 1, so they will not be described again in this embodiment. Example 3

[0048] like Figure 19 and Figure 20 As shown, where, Figure 19 This is a schematic diagram of the structure of the first type of liquid chromatography pump; Figure 20This is a schematic diagram of the structure of the second type of liquid chromatography pump. Specifically, this embodiment provides another type of liquid chromatography pump, which is equipped with either the pump head structure in Embodiment 1 or the pump head structure in Embodiment 2. Either pump head structure can be selected arbitrarily, thereby significantly reducing the delay volume of the mixed mobile phase, improving the efficiency of liquid chromatography analysis of the sample, and effectively preventing sample diffusion.

[0049] Other embodiments of the present invention will readily occur to those skilled in the art upon consideration of the specification and practice of the solutions disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

Claims

1. A pump head structure, comprising a pump head upper end cover (2.1), a pump head housing (2.3), a pump head lower end cover (2.4), at least two inlet check valve assemblies (2.2), and at least two outlet check valve assemblies (2.5); characterized in that, The pump head upper cover (2.1) is provided with an internal pipe (2.1.14), and the internal pipe (2.1.14) is connected to the outlet check valve assembly (2.5) by a first connecting pipe (2.1.15). The pump head housing (2.3) is provided with a second connecting pipe (2.3.4), which is connected to a plunger rod actuation pipe (2.3.3) for plunger rod insertion. The second connecting pipe (2.3.4) is connected to the outlet check valve assembly (2.5) and the inlet check valve assembly (2.2). The pump head lower end cover (2.4) is provided with an internal pipe (2.4.3), and the internal pipe (2.4.3) of the lower end cover is connected to the inlet one-way valve assembly (2.2) by a third connecting pipe (2.4.4).

2. The pump head structure according to claim 1, characterized in that, A manual vent valve (2.1.1) is provided on one side of the upper cover (2.1) of the pump head.

3. The pump head structure according to claim 2, characterized in that, The pump head upper cover (2.1) includes an upper cover housing (2.1.13) and a pressure sensor (2.1.3), and the pressure sensor (2.1.3) is provided inside the upper cover housing (2.1.13).

4. The pump head structure according to claim 3, characterized in that, The upper end cover housing (2.1.13) is also provided with a mixer arranged separately from the pressure sensor (2.1.3).

5. The pump head structure according to any one of claims 1-4, characterized in that, The pump head housing (2.3) is provided with at least two spaced plunger rod working chamber bushings (2.3.1) for connecting to one end of the plunger rod.

6. The pump head structure according to any one of claims 1-4, characterized in that, The inlet check valve assembly (2.2) includes a check valve connection seal (2.2.5) and at least two first mounting sleeves (2.2.2). The first mounting sleeve (2.2.2) is provided at both ends of the one-way valve connecting sealing ring (2.2.5); the first mounting sleeve (2.2.2) is provided at the end away from the one-way valve connecting sealing ring (2.2.5) with a first one-way valve outlet sealing ring (2.2.1); a first ball seat (2.2.4) is provided between the first mounting sleeve (2.2.2) and the one-way valve connecting sealing ring (2.2.5), and a first one-way valve ball (2.2.3) is provided on the first ball seat (2.2.4).

7. The pump head structure according to any one of claims 1-4, characterized in that, The outlet check valve assembly (2.5) includes a second mounting sleeve (2.5.2) and at least two second check valve outlet seals (2.5.1). The second mounting sleeve (2.5.2) is provided with a second one-way valve outlet sealing ring (2.5.1) at both ends. The second mounting sleeve (2.5.2) is provided with a guide pin (2.5.4), a second ball seat (2.5.6) and a second filter screen mounting gasket (2.5.7). An elastic reset member (2.5.3) is sleeved on the guide pin (2.5.4), and one end of the elastic reset member (2.5.3) abuts against the second mounting sleeve (2.5.2); The second ball seat (2.5.6) is located on one side of the guide pin (2.5.4), and the second ball seat (2.5.6) is provided with a second one-way valve ball (2.5.5) on the side of the guide pin (2.5.4). The second filter screen mounting gasket (2.5.7) is located between the second ball seat (2.5.6) and one of the second one-way valve outlet sealing rings (2.5.1).

8. The pump head structure according to any one of claims 1-4, characterized in that, A cleaning seat (1) is provided on one side of the pump head housing (2.3), and at least two sets of spaced sealing ring assemblies are provided on the cleaning seat (1).

9. The pump head structure according to claim 8, characterized in that, The sealing ring assembly includes a first sealing ring (1.1), a second sealing ring (1.2), and a third sealing ring (1.4). The first sealing ring (1.1) is provided on the cleaning seat (1), the first sealing ring (1.1) is provided with the second sealing ring (1.2), the second sealing ring (1.2) is provided with the second sealing ring bushing (1.3), and the second sealing ring bushing (1.3) is provided with the third sealing ring (1.4) on the side of the second sealing ring bushing (1.3) away from the second sealing ring (1.2).

10. A liquid chromatography pump, characterized in that, The pump head structure includes any one of claims 1-9.

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