A sealing structure for a pump and an ion chromatography pump

Abstract

The application relates to the technical field of analytical instruments, and particularly discloses a sealing structure for a pump and an ion chromatography pump, wherein a stepped hole is formed between a low-pressure cavity and a high-pressure cavity of a pump shell; in the pump shell, a piston rod can make reciprocating linear motion relative to a pump body; a sealing sleeve is installed in the stepped hole and sleeved on the piston rod, a small-diameter section of the sealing sleeve comprises an inner ring and an outer ring which are arranged at intervals in the radial direction, the inner ring is attached to the outer peripheral wall of the piston rod, the outer ring is attached to the inner peripheral wall of the stepped hole, a placing groove is formed at the joint of the small-diameter section and a first large-diameter section, the placing groove is in communication at the head and tail around the axis, the outer side wall of the first large-diameter section is tightly attached to the inner side wall of the stepped hole; a first sealing ring is at least partially located in the placing groove and can be elastically deformed; the hardness of the first sealing ring is smaller than that of the sealing sleeve. The sealing sleeve and the first sealing ring both have the effect that the sealing capacity increases with the increase of the pressure of the high-pressure cavity, and multi-stage sealing is formed along the leakage direction of the fluid, which further improves the reliability of the sealing.

Description

Technical Field

[0001] This invention relates to the field of analytical instrument technology, and in particular to a pump sealing structure and an ion chromatography pump. Background Technology

[0002] The ion chromatography pump is the core high-pressure delivery component of an ion chromatograph. It is mainly used to pump the detection solution under high pressure with precision. The leak-proof performance of its internal sealing structure is a key element to ensure the normal operation of the equipment and the accuracy of the detection results.

[0003] Traditional ion chromatography pumps typically employ a single sealing ring for internal sealing. This ring can only be either a hard or soft material. While a hard seal can withstand the high pressure during pumping, its poor fit between the ring and the pump body's sealing surface can easily create tiny gaps, potentially leading to slight leakage under high pressure. This leakage not only affects the flow rate accuracy but can also contaminate internal components. A soft seal, on the other hand, provides better fit and short-term leak prevention. However, the soft material's pressure resistance is insufficient, and under continuous high pressure, it is prone to irreversible deformation, wear, or even breakage. This causes rapid seal failure, resulting in significant leakage and requiring frequent ring replacements, increasing maintenance costs.

[0004] Therefore, there is an urgent need for a pump sealing structure and an ion chromatography pump to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a pump sealing structure and an ion chromatography pump to solve the problems of poor sealing effect, short service life and low reliability.

[0006] On one hand, the present invention provides a pump sealing structure, the pump sealing structure comprising: The pump casing includes a low-pressure chamber and a high-pressure chamber, with a stepped hole formed between the low-pressure chamber and the high-pressure chamber. The piston rod is located inside the pump housing and is capable of reciprocating linear motion relative to the pump body. The head of the piston rod is located in the high-pressure chamber, and the rod portion of the piston rod is located in the low-pressure chamber. A sealing sleeve is installed in the stepped hole and fitted onto the piston rod. The sealing sleeve includes a small diameter section, a placement groove, and a first large diameter section. The small diameter section includes an inner ring and an outer ring arranged radially at intervals. The inner ring fits against the outer peripheral wall of the piston rod, and the outer ring fits against the inner peripheral wall of the stepped hole. The placement groove is formed at the junction of the small diameter section and the first large diameter section. The placement groove is connected end to end around the axis. The radius of the first large diameter section is larger than the radius of the small diameter section. The outer side wall of the first large diameter section is in close contact with the inner side wall of the stepped hole. The first sealing ring is at least partially located within the aforementioned placement groove and is capable of elastic deformation. The hardness of the first sealing ring is less than that of the sealing sleeve.

[0007] As a preferred embodiment of the above-mentioned pump sealing structure, the pump sealing structure further includes a second sealing ring, which is placed between the inner ring and the outer ring of the small diameter section and abuts against both of them radially, and the second sealing ring is capable of elastic deformation.

[0008] As a preferred embodiment of the above-mentioned pump sealing structure, along the axial direction of the piston rod, the stepped hole includes a first end face and a second end face, with the first end face located on the high-pressure chamber side. The aforementioned sealing sleeve also includes a second large diameter section, which is located on the side of the first large diameter section opposite to the small diameter section and has a larger radius than the first large diameter section. The second large diameter section is in close contact with the second end face along the axial direction, and the inner ring and the outer ring are spaced apart from the first end face along the axial direction.

[0009] As a preferred embodiment of the above-mentioned pump sealing structure, the pump sealing structure further includes a base plate, which is fixed relative to the pump housing, and the second large diameter section is sandwiched between the second end face and the base plate along the axial direction.

[0010] As a preferred embodiment of the above-mentioned pump sealing structure, the base plate has a tapered hole, the piston rod is inserted into the tapered hole, and along the axial direction from the low-pressure chamber to the high-pressure chamber, the radius of the tapered hole gradually decreases.

[0011] As a preferred embodiment of the above-mentioned pump sealing structure, the pump sealing structure further includes a pressure block, which is sandwiched between the sealing sleeve and the base plate along the axial direction.

[0012] An ion chromatography pump is also provided, including the pump sealing structure described above.

[0013] As a preferred embodiment of the aforementioned ion chromatography pump, the ion chromatography pump further includes: The fluid inlet check valve, installed at the inlet of the high-pressure chamber, allows fluid to flow into the high-pressure chamber in one direction. The fluid outflow check valve, installed at the drain port of the aforementioned high-pressure chamber, allows fluid to flow unidirectionally out of the aforementioned high-pressure chamber.

[0014] As a preferred embodiment of the aforementioned ion chromatography pump, the inlet of the high-pressure chamber and the outlet of the high-pressure chamber are spaced apart along the aforementioned axial direction.

[0015] As a preferred embodiment of the ion chromatography pump, the ion chromatography pump further includes a post-cleaning block and a water pipe. The post-cleaning block is sleeved outside the piston rod and is fixed relative to the pump housing. The post-cleaning block obtains clean water through the water pipe.

[0016] The pump sealing structure provided by this invention has at least the following beneficial effects: The pump body has a low-pressure chamber and a high-pressure chamber formed along a first direction. A stepped hole is formed at the connection between the low-pressure chamber and the high-pressure chamber. The diameter of the stepped hole decreases progressively from the low-pressure chamber towards the high-pressure chamber. For example, it includes a first-stage stepped hole and a second-stage stepped hole. The first-stage stepped hole is located on the high-pressure chamber side, and the second-stage stepped hole is located on the low-pressure chamber side; that is, the diameter of the first-stage stepped hole is smaller than the diameter of the second-stage stepped hole. A piston chamber is inserted into the pump casing and can perform linear reciprocating motion along the first direction, thereby pressurizing or depressurizing the high-pressure chamber. The sealing sleeve is installed at the stepped hole and remains relatively fixed to the pump body. The sealing sleeve is fitted onto the piston rod and moves relative to it. The sealing sleeve is stepped and adapted to the stepped hole. For example, it includes a small-diameter section and a first large-diameter section. The small-diameter section is inserted into the first-stage stepped hole, and the first large-diameter section is inserted into the second-stage stepped hole. A U-shaped groove is formed on the axial end face of the small-diameter section opposite to the first large-diameter section. The U-shaped groove is circular, connecting end to end around the piston rod's axis. The opening of the U-shaped groove faces the high-pressure chamber. The opposite radial side walls of the U-shaped groove on the piston rod form the inner and outer rings. The outer ring is tightly fitted against the inner circumferential wall of the first-stage stepped hole, forming the first sealing area. The inner ring is tightly fitted against the outer circumferential wall of the piston rod, forming the second sealing area. The area consists of the outer wall of the first large-diameter section and the inner circumferential wall of the second-stage stepped hole. A placement groove is formed between the small-diameter section and the first large-diameter section. The placement groove is connected end to end around the axis to form a ring shape. The depth direction of the placement groove is perpendicular to the axial direction of the piston rod. The two opposite side walls of the placement groove, which are axially spaced, are referred to as the first side wall and the second side wall. The first side wall is connected to the outer wall of the small-diameter section, and the second side wall is connected to the outer wall of the first large-diameter section. Alternatively, it can be understood that, projected along the axial direction, the edge contour of the second side wall is located outside the edge contour of the first side wall. A first sealing ring is installed in the placement groove. Part of the first sealing ring is located inside the placement groove, and the other part is located outside the placement groove and abuts against the inner circumferential wall of the second-stage stepped hole, forming a third sealing area.

[0017] As the piston rod moves into the high-pressure chamber, the pressure inside increases, causing the fluid within to tend to flow towards the low-pressure chamber along the piston rod. Some fluid enters the U-shaped groove between the inner and outer rings in the smaller diameter section. This fluid entry increases the pressure within the U-shaped groove, causing the inner and outer rings to move further apart radially along the piston rod. The inner ring then adheres more tightly to the outer wall of the piston rod, while the outer ring adheres more tightly to the outer wall of the first-stage stepped bore. Furthermore, as the pressure within the high-pressure chamber increases, the fit between the inner ring and the piston rod, and between the outer ring and the pump housing, becomes even tighter. As the piston rod exits the high-pressure chamber, the pressure inside decreases, and the pressure within the U-shaped groove decreases accordingly. Although the inner ring and piston rod, and the outer ring and pump housing, remain in close contact, the pressure decreases, allowing the piston rod to exit the high-pressure chamber more smoothly.

[0018] Furthermore, when the pressure inside the high-pressure chamber is too high, causing the fluid to break through the first sealing area, the fluid further compresses the first sealing ring axially. The first sealing ring can undergo elastic deformation, and the side of the first sealing ring facing away from the high-pressure chamber is supported by a second sidewall with a placement groove. The first sealing ring is clamped between the fluid and the second sidewall along the axial direction of the piston rod, making it easier for the first sealing ring to extend radially along the piston rod. This makes the outer side of the first sealing ring abut against the pump housing more tightly, and the inner side of the first sealing ring abut against the sealing sleeve more tightly. Thus, as the pressure increases, the sealing effect formed by the first sealing ring also increases.

[0019] Furthermore, the hardness of the first sealing ring is less than that of the sealing sleeve. Since the piston rod is inserted into the sealing sleeve and needs to make linear reciprocating motion, there is both relative movement between the two and the need to achieve sealing. Therefore, the sealing sleeve uses a relatively hard material to improve its wear resistance, while the first sealing ring uses a relatively soft material to make it more prone to deformation.

[0020] In this way, both the sealing sleeve and the first sealing ring have the effect of increasing their sealing capacity as the pressure in the high-pressure chamber increases, and the two form a multi-stage seal along the leakage direction of the fluid, which further improves the reliability of the seal. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the ion chromatography pump in an embodiment of the present invention; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the sealing sleeve in an embodiment of the present invention; Figure 4 for Figure 3 A sectional view.

[0022] In the picture: 1. Pump casing; 2. Piston rod; 3. Sealing sleeve; 31. Small diameter section; 311. Outer ring; 312. Inner ring; 32. First large diameter section; 33. Placement groove; 34. Second large diameter section; 4. First sealing ring; 5. Second sealing ring; 6. Base plate; 61. Taper hole; 7. Press block; 81. Fluid inlet check valve; 82. Fluid outlet check valve. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] like Figures 1 to 4 As shown, this embodiment provides a pump sealing structure, which includes a pump housing 1, a piston rod 2, a sealing sleeve 3, and a first sealing ring 4. The pump housing 1 includes a low-pressure chamber and a high-pressure chamber, with a stepped hole forming between them. Inside the pump housing 1, the piston rod 2 can reciprocate linearly relative to the pump body. The head of the piston rod 2 is located in the high-pressure chamber, and the rod portion is located in the low-pressure chamber. The sealing sleeve 3 is installed in the stepped hole and fitted onto the piston rod 2. The sealing sleeve 3 includes a small-diameter section 31, a placement groove 33, and a first large-diameter section 32. The small-diameter section 31 includes an inner ring 312 and an outer ring 311 spaced radially apart. 2 is in contact with the outer peripheral wall of piston rod 2, outer ring 311 is in contact with the inner peripheral wall of stepped hole, placement groove 33 is formed at the junction of small diameter section 31 and first large diameter section 32, placement groove 33 is connected end to end around axis, the radius of first large diameter section 32 is larger than the radius of small diameter section 31, the outer side wall of first large diameter section 32 is in close contact with inner side wall of stepped hole; first sealing ring 4 is at least partially located in placement groove 33 and can undergo elastic deformation; the hardness of first sealing ring 4 is less than the hardness of sealing sleeve 3.

[0028] For example, the pump body has a low-pressure chamber and a high-pressure chamber formed along a first direction. A stepped hole is formed at the connection between the low-pressure chamber and the high-pressure chamber. From the low-pressure chamber to the high-pressure chamber, the diameter of the stepped hole decreases step by step. For example, it includes a first-stage stepped hole and a second-stage stepped hole. The first-stage stepped hole is located on the high-pressure chamber side, and the second-stage stepped hole is located on the low-pressure chamber side. That is, the diameter of the first-stage stepped hole is smaller than the diameter of the second-stage stepped hole. The piston chamber is inserted into the pump casing 1 and can perform linear reciprocating motion along the first direction, thereby pressurizing or depressurizing the high-pressure chamber. The sealing sleeve 3 is installed at the stepped hole and is relatively fixed to the pump body. The sealing sleeve 3 is sleeved on the piston rod 2 and moves relative to the piston rod 2. The sealing sleeve 3 is stepped and adapted to the stepped hole. For example, it includes a small diameter section 31 and a first large diameter section 32. The small diameter section 31 is inserted into the first-stage stepped hole, and the first large diameter section 32 is inserted into the second-stage stepped hole. The axial end face of the small diameter section 31 opposite to the first large diameter section 32 has a U-shaped groove. The U-shaped groove is connected end to end around the axis of the piston rod 2 and is circular. The opening of the U-shaped groove faces the high-pressure chamber side. The opposite side walls of the U-shaped groove in the radial direction of the piston rod 2 are the inner ring 312 and the outer ring 311. The outer ring 311 is tightly attached to the inner peripheral wall of the first-stage stepped hole to form the first sealing area, and the inner ring 312 is tightly attached to the outer peripheral wall of the piston rod 2 to form the second sealing area. Sealing area; the outer wall of the first large diameter section 32 is in close contact with the inner peripheral wall of the second-stage stepped hole. A placement groove 33 is formed between the small diameter section 31 and the first large diameter section 32. The placement groove 33 is connected end to end around the axis to form a ring shape. The depth direction of the placement groove 33 is perpendicular to the axial direction of the piston rod 2. The opposite side walls of the placement groove 33 at axial intervals are referred to as the first side wall and the second side wall. The first side wall is connected to the outer wall of the small diameter section 31, and the second side wall is connected to the outer wall of the first large diameter section 32. It can also be understood that, along the axial projection, the edge contour of the second side wall is located outside the edge contour of the first side wall. A first sealing ring 4 is installed in the placement groove 33. A part of the first sealing ring 4 is located in the placement groove 33, and another part is located outside the placement groove 33 and abuts against the inner peripheral wall of the second-stage stepped hole to form a third sealing area.

[0029] As piston rod 2 moves into the high-pressure chamber, the pressure inside the high-pressure chamber increases, and the fluid inside tends to flow along piston rod 2 towards the low-pressure chamber. Some fluid enters the U-shaped groove between the inner ring 312 and the outer ring 311 of the small-diameter section 31. The entry of fluid causes the pressure in the U-shaped groove to increase, causing the inner ring 312 and the outer ring 311 to move away from each other radially along piston rod 2. The inner ring 312 then adheres more tightly to the outer wall of piston rod 2, and the outer ring 311 adheres more tightly to the outer wall of the first-stage stepped hole. Furthermore, as the pressure in the high-pressure chamber increases, the adhesion between the inner ring 312 and piston rod 2 and between the outer ring 311 and pump housing 1 becomes even tighter. As piston rod 2 exits the high-pressure chamber, the pressure inside the high-pressure chamber decreases, and the pressure in the U-shaped groove decreases accordingly. Although the inner ring 312 and piston rod 2, and the outer ring 311 and pump housing 1 remain in a tight-fitting state, the pressure decreases, allowing piston rod 2 to exit the high-pressure chamber more smoothly.

[0030] Furthermore, when the pressure inside the high-pressure chamber is too high, causing the fluid to break through the first sealing area, the fluid further compresses the first sealing ring 4 axially. The first sealing ring 4 can undergo elastic deformation, and the side of the first sealing ring 4 facing away from the high-pressure chamber is supported by the second sidewall of the placement groove 33. The first sealing ring 4 is sandwiched between the fluid and the second sidewall along the axial direction of the piston rod 2, making it easier for the first sealing ring 4 to extend radially along the piston rod 2. This makes the outer side of the first sealing ring 4 abut against the pump housing 1 more tightly, and the inner side of the first sealing ring 4 abut against the sealing sleeve 3 more tightly. Thus, as the pressure increases, the sealing effect formed by the first sealing ring 4 is also enhanced.

[0031] Furthermore, the hardness of the first sealing ring 4 is less than that of the sealing sleeve 3. Since the piston rod 2 is inserted into the sealing sleeve 3 and needs to make linear reciprocating motion, there is both relative movement between the two and the need to achieve sealing. Therefore, the sealing sleeve 3 uses a relatively hard material to improve its wear resistance, while the first sealing ring 4 uses a relatively soft material, making it easier to deform.

[0032] Thus, both the sealing sleeve 3 and the first sealing ring 4 have the effect of increasing their sealing capacity as the pressure in the high-pressure chamber increases, and the two form a multi-stage seal along the leakage direction of the fluid, which further improves the reliability of the seal.

[0033] It should be noted that the first direction of the pump housing 1 is parallel to the axial direction of the piston rod 2.

[0034] For example, the sealing ring is made of plastic, and the first sealing ring 4 is made of rubber.

[0035] Optionally, a protrusion is provided on the side of the outer ring 311 opposite to the inner ring 312. The protrusion is connected end to end in a ring shape around the axis of the piston rod 2. A limiting groove is formed on the inner peripheral wall of the first-stage stepped hole of the stepped hole. The protrusion is inserted into the limiting groove, and the side wall of the limiting groove opposite to the high-pressure chamber always provides support for the protrusion. With this configuration, on the one hand, the protrusion and the limiting groove are used to fix the relative position of the sealing sleeve 3 and the pump housing 1, which can effectively prevent misalignment. On the other hand, the assembly of the protrusion and the groove forms a labyrinth seal, which can effectively prevent fluid leakage.

[0036] Furthermore, the protrusion on the side of the outer ring 311 opposite to the inner ring 312 has an external thread structure, and the limiting groove on the inner wall of the first-stage stepped hole has an internal thread structure, forming a threaded connection between the sealing sleeve 3 and the pump housing 1.

[0037] Optionally, the pump sealing structure also includes a second sealing ring 5. The second sealing ring 5 is placed between the inner ring 312 and the outer ring 311 of the small-diameter section 31 and abuts against both radially. The second sealing ring 5 is capable of elastic deformation. When the pressure in the high-pressure chamber increases, fluid enters the U-shaped groove, creating axial compression on the second sealing ring 5. The second sealing ring 5 is capable of elastic deformation and also has a tendency to deform radially along the piston rod 2, thereby supporting the inner ring 312 to be closer to the piston rod 2 and the outer ring 311 to be closer to the pump housing 1. This improves the sealing capability of the first sealing area and the second sealing area.

[0038] Optionally, along the axial direction of the piston rod 2, the stepped hole includes a first end face and a second end face, with the first end face located on the high-pressure chamber side; the sealing sleeve 3 also includes a second large-diameter section 34, which is located on the side of the first large-diameter section 32 opposite to the small-diameter section 31 and has a radius larger than the first large-diameter section 32. The second large-diameter section 34 is in close contact with the second end face along the axial direction, and the inner ring 312 and the outer ring 311 are both spaced apart from the first end face along the axial direction.

[0039] For example, the axial end of the small-diameter section 31 of the sealing sleeve 3 is spaced apart from the first end face to form a flow channel, allowing the fluid in the high-pressure chamber to enter the U-shaped groove more smoothly and act on the inner ring 312 and the outer ring 311. The second large-diameter section 34 and the second end face abut against each other axially near the low-pressure side to form a fourth sealing area, thereby improving the sealing effect.

[0040] Optionally, the pump sealing structure also includes a base plate 6, which is fixed relative to the pump housing 1, and the second large diameter section 34 is sandwiched between the second end face and the base plate 6 along the axial direction.

[0041] For example, the substrate 6 is fixed to the end face of the stepped hole facing the low-pressure cavity, for sealing the sealing sleeve 3 inside the stepped hole.

[0042] Furthermore, the base plate 6 is fixed inside the pump housing 1 by threaded fasteners.

[0043] Optionally, the substrate 6 has a tapered hole 61, and the piston rod 2 is inserted into the tapered hole 61. Along the axial direction, from the low-pressure chamber to the high-pressure chamber, the radius of the tapered hole 61 gradually decreases.

[0044] Optionally, the pump sealing structure also includes a pressure block 7, which is axially sandwiched between the sealing sleeve 3 and the base plate 6.

[0045] For example, the pressure block 7 is an elastic element used to fill the gap between the substrate 6 and the sealing sleeve 3.

[0046] An ion chromatography pump is also provided, including the pump sealing structure described above.

[0047] Optionally, the ion chromatography pump also includes a fluid inlet check valve 81 and a fluid outlet check valve 82. The fluid inlet check valve 81 is installed at the inlet of the high-pressure chamber and allows fluid to flow into the high-pressure chamber in one direction only; the fluid outlet check valve 82 is installed at the outlet of the high-pressure chamber and allows fluid to flow out of the high-pressure chamber in one direction only.

[0048] Optionally, the inlet and outlet of the high-pressure chamber are spaced apart along the axial direction.

[0049] Optionally, the ion chromatography pump also includes a post-cleaning block and a water pipe. The post-cleaning block is sleeved outside the piston rod 2 and fixed relative to the pump housing 1. The post-cleaning block obtains clean water through the water pipe.

[0050] For example, the post-cleaning block obtains clean water from the clean water pipe, and the wetted post-cleaning block is sleeved on the piston rod 2. When the piston rod 2 moves, the post-cleaning block and the piston rod 2 form a relative movement. The post-cleaning block wets and wipes the outer peripheral wall of the piston rod 2 to prevent the washing liquid from crystallizing on the surface of the piston rod 2. If crystallization occurs, the reciprocating movement of the piston rod 2 relative to the sealing sleeve 3 causes the crystals to repeatedly rub against the sealing sleeve 3, damaging the sealing effect of the sealing sleeve 3.

[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A pump sealing structure, characterized in that, include: Pump casing (1) includes a low-pressure chamber and a high-pressure chamber, wherein a stepped hole is formed between the low-pressure chamber and the high-pressure chamber; The piston rod (2) is located inside the pump housing (1). The piston rod (2) is capable of reciprocating linear motion relative to the pump body. The head of the piston rod (2) is located in the high-pressure chamber, and the rod part of the piston rod (2) is located in the low-pressure chamber. A sealing sleeve (3) is installed in the stepped hole and sleeved on the piston rod (2). The sealing sleeve (3) includes a small diameter section (31), a placement groove (33), and a first large diameter section (32). The small diameter section (31) includes an inner ring (312) and an outer ring (311) arranged radially at intervals. The inner ring (312) fits against the outer peripheral wall of the piston rod (2), and the outer ring (311) fits against the inner peripheral wall of the stepped hole. The placement groove (33) is formed at the junction of the small diameter section (31) and the first large diameter section (32). The placement groove (33) is connected end to end around the axis. The radius of the first large diameter section (32) is greater than the radius of the small diameter section (31). The outer side wall of the first large diameter section (32) is in close contact with the inner side wall of the stepped hole. The first sealing ring (4) is at least partially located within the placement groove (33) and is capable of elastic deformation; The hardness of the first sealing ring (4) is less than that of the sealing sleeve (3).

2. The pump sealing structure according to claim 1, characterized in that, It also includes a second sealing ring (5), which is placed between the inner ring (312) and the outer ring (311) of the small diameter section (31) and abuts against both of them radially. The second sealing ring (5) is capable of elastic deformation.

3. The pump sealing structure according to claim 1, characterized in that, Along the axial direction of the piston rod (2), the stepped hole includes a first end face and a second end face, the first end face being located on the high-pressure chamber side; The sealing sleeve (3) further includes a second large diameter section (34), which is located on the side of the first large diameter section (32) opposite to the small diameter section (31) and has a radius greater than that of the first large diameter section (32). The second large diameter section (34) is in close contact with the second end face along the axial direction. The inner ring (312) and the outer ring (311) are both spaced apart from the first end face along the axial direction.

4. The pump sealing structure according to claim 3, characterized in that, It also includes a substrate (6), which is fixed relative to the pump housing (1), and along the axial direction, the second large diameter section (34) is sandwiched between the second end face and the substrate (6).

5. The pump sealing structure according to claim 4, characterized in that, The substrate (6) has a conical hole (61), and the piston rod (2) is inserted into the conical hole (61). Along the axial direction, from the low-pressure chamber to the high-pressure chamber, the radius of the conical hole (61) gradually decreases.

6. The pump sealing structure according to claim 4, characterized in that, It also includes a pressure block (7), which is sandwiched between the sealing sleeve (3) and the substrate (6) along the axial direction.

7. An ion chromatography pump, characterized in that, Includes the pump sealing structure as described in any one of claims 1-6.

8. The ion chromatography pump according to claim 7, characterized in that, Also includes: A fluid inlet check valve (81) is installed at the inlet of the high-pressure chamber, allowing fluid to flow unidirectionally into the high-pressure chamber; The fluid outflow check valve (82), installed at the drain port of the high-pressure chamber, allows fluid to flow unidirectionally out of the high-pressure chamber.

9. The ion chromatography pump according to claim 7, characterized in that, The inlet and outlet of the high-pressure chamber are spaced apart along the axial direction.

10. The ion chromatography pump according to claim 7, characterized in that, It also includes a post-cleaning block and a clean water pipe. The post-cleaning block is sleeved outside the piston rod (2) and fixed relative to the pump housing (1). The post-cleaning block obtains clean water through the clean water pipe.

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