Sealing structure of hydraulic direct-drive plunger pump and plunger pump

Abstract

The utility model relates to the technical field, in particular to a sealing structure of a hydraulic direct drive type plunger pump and the plunger pump, the plunger pump comprises a channel used for arranging a plunger in a penetrating mode, and the plunger can do axial reciprocating motion along the channel. The sealing structure comprises a first sealing piece, a second sealing piece and a drainage space. The first sealing piece and the second sealing piece are arranged in the channel in the axial direction in a spaced mode and surround the peripheral wall of the plunger. The discharge space is located at the interval position between the first sealing piece and the second sealing piece, at least part of the plunger is exposed in the discharge space, and the discharge space communicates with a water inlet runner of the plunger pump; high-pressure water leaked from the sealing position of the first sealing piece enters the pressure relief space and then is relieved, the water pressure is greatly reduced, and therefore the situation that the high-pressure water enters the oil cavity to affect the action of a reversing mechanism in the oil cavity is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field, in particular to a sealing structure of a hydraulic direct-drive plunger pump and the plunger pump. Background Art

[0002] A hydraulic direct-drive plunger pump refers to a pump structure that uses hydraulic propulsion to drive the plunger to move axially back and forth to achieve high-pressure pumping of liquid.

[0003] It is generally composed of a pump casing and a plunger assembly arranged in the pump casing, and the plunger assembly includes a plunger and a reversing mechanism; the plunger can move back and forth axially between two dead point positions; when in use, hydraulic oil is injected into the oil chamber in the pump casing, and the plunger assembly is pushed to one side under the action of the pressure of the hydraulic oil. When the plunger moves to the dead point position on that side, the reversing mechanism inside the plunger assembly completes the reversal, so that the hydraulic oil pushes the plunger assembly to the other dead point position, and this cycle is repeated, pushing the plunger assembly to move back and forth between the two dead point positions, thereby squeezing the water in the water chamber to achieve water pumping.

[0004] Since the water in the water chamber will generate a large water pressure under the squeeze of the plunger assembly, if this part of the water pressure is pressed into the oil chamber, the reversing mechanism will find it difficult to achieve normal reversing due to the obstruction of the water pressure, thus causing the plunger pump to malfunction.

[0005] Therefore, in related art, a sealing structure such as a sealing ring is generally installed in the channel through which the plunger passes to ensure a tight seal between the outer peripheral wall of the plunger and the peripheral wall of the channel, thereby preventing the high-pressure water in the water chamber from being pressed into the oil chamber through the channel. For an example of such a sealing structure, reference can be made to the hydraulic booster disclosed in Publication No. CN211116858U.

[0006] The above-mentioned method of sealing with only a sealing ring still has defects in use. It is understandable that even if a sealing ring is set, as the plunger moves back and forth for a long time, friction between the piston and the sealing ring will cause small leakage at the sealing ring position. Although it is a small leakage, as the plunger pushes, the water pressure in the water chamber is very high, so the leaked water will still enter the oil chamber in a high-pressure state, thereby affecting the action of the reversing mechanism in the oil chamber; therefore, there is still room for improvement. Utility Model Content

[0007] In order to solve at least one of the technical problems mentioned in the background technology, the purpose of the present invention is to provide a sealing structure of a hydraulic direct-drive plunger pump and a plunger pump.

[0008] To achieve the above objectives, the present invention provides the following technical solutions:

[0009] On the one hand, the utility model provides a sealing structure of a hydraulic direct-drive plunger pump, wherein the plunger pump includes a channel for penetrating a plunger, and the plunger can perform axial reciprocating movement along the channel, and the sealing structure includes a first seal, a second seal and a leakage space; the first seal and the second seal are axially spaced apart in the channel and surround the outer peripheral wall of the plunger; the leakage space is located at the interval between the first seal and the second seal, the plunger is at least partially exposed in the leakage space, and the leakage space is connected to the water inlet channel of the plunger pump.

[0010] As an optional implementation of the present invention, the leakage space is an annular space and surrounds the outer circumference of the plunger.

[0011] As an optional implementation of the present invention, a leakage flow channel is opened in the pump housing, and the leakage flow space is connected with the water inlet flow channel of the plunger pump through the leakage flow channel.

[0012] As an optional embodiment of the present invention, the first sealing member is a combined sealing ring, comprising a support ring, a main water seal, and a baffle that are sequentially abutted or fixed along the axial direction.

[0013] On the other hand, the utility model also provides a plunger pump, including a pump casing and a plunger assembly, the plunger assembly including a plunger, the pump casing is provided with an oil chamber, a water chamber, and a channel between the water chamber and the oil chamber; the plunger is penetrated in the channel, and can reciprocate along the channel driven by the oil pressure in the oil chamber to drive the water chamber to absorb and pump water; the pump casing is also provided with two flow channels for water circulation, of which one constitutes a water inlet channel and the other constitutes a water outlet channel; a sealing structure is provided between the channel and the outer peripheral wall of the plunger, and the sealing structure adopts the sealing structure of the above-mentioned hydraulic direct-drive plunger pump.

[0014] As an optional embodiment of the present invention, the pump casing includes a main casing and end casings arranged at both ends of the main casing. The flow channel is at least partially located on the end casing to form a branch flow channel. The end casing can also be detachably installed with a one-way valve for controlling the on / off of the branch flow channel.

[0015] As an optional embodiment of the present invention, the end shell is provided with an installation port for installing the one-way valve, the installation port has a stepped surface, and the one-way valve is pressed against the stepped surface by a pressing member.

[0016] As an optional implementation of the present invention, the pressing member is threadedly connected to the mounting port.

[0017] As an optional embodiment of the present invention, the water cavity includes two groups, and the two groups of water cavities are respectively located on both sides of the oil cavity; the two ends of the flow channel are respectively connected to the two water cavities; the two one-way valves arranged on the water inlet flow channel are recorded as first one-way valves, and the two one-way valves arranged on the water outlet flow channel are recorded as second one-way valves; the first one-way valve is constructed to allow water in the water inlet flow channel to flow to the water cavity in one direction, and the second one-way valve is constructed to allow water in the water cavity to flow to the water outlet flow channel in one direction.

[0018] As an optional embodiment of the present invention, the flow channel further includes a main flow channel connected to the branch flow channel, and the main flow channels of the two flow channels are respectively located on both sides of the main shell.

[0019] Compared with the existing technology, the advantages of adopting this solution are:

[0020] When the sealing structure provided by the present invention is applied to a plunger pump, if the first sealing component is not sealed tightly and leakage occurs at the sealing position, the leaked high-pressure water will flow into the leakage space, and the leakage space is connected to the water inlet flow channel, so the internal water pressure thereof is basically similar to the water pressure in the water inlet flow channel, and the water pressure will not be very high. Therefore, at this time, the high-pressure water leaked at the sealing position of the first sealing component enters the pressure relief space and is relieved, and the water pressure is greatly reduced, so that the high-pressure water will not enter the oil chamber and affect the action of the reversing mechanism in the oil chamber.

[0021] In addition, it can be understood that because the water pressure of the leaked high-pressure water decreases after entering the leakage space, the impact on the second sealing component is reduced at this time, thereby increasing the service life of the second sealing component.

[0022] Finally, connecting the discharge space with the water inlet channel can not only relieve the pressure of the leaked high-pressure water, but also allow the water in the water inlet channel to enter the discharge space, so that the entering water contacts the peripheral wall of the plunger. In this way, the piston can be cooled by the entering water, and the entering water can also play a certain lubricating role on the peripheral wall of the piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of the utility model;

[0024] Figure 2 It is a cross-sectional view of the utility model;

[0025] Figure 3 for Figure 2 A partial enlarged view of the

[0026] Figure 4 for Figure 4 Enlarged view of part A in the middle;

[0027] Figure 5This is a schematic diagram of the sealing structure position of the present invention. DETAILED DESCRIPTION

[0028] The following is an explanation and description of the technical solutions of the embodiments of the present invention in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention and are not exhaustive. Based on the embodiments in the embodiments, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0029] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0030] Example 1

[0031] See Figure 1-5 As shown, the present invention provides a sealing structure primarily for a hydraulic direct-drive plunger pump. It is understood that a hydraulic direct-drive plunger pump is a pump that uses hydraulic pressure as a power source to move a plunger 21 to pump water, such as hydraulic oil. For ease of description, the hydraulic direct-drive plunger pump will be referred to as a plunger pump.

[0032] like Figure 2 As shown, the plunger pump mainly includes a pump housing 1 and a plunger assembly. The pump housing 1 is provided with an oil chamber 111, a water chamber 121, and a channel 13 located between the water chamber 121 and the oil chamber 111;

[0033] like Figure 1 As shown, the oil chamber 111 is used for supplying hydraulic oil. In addition, an oil inlet 111a and an oil outlet 111b connected to the oil chamber 111 are provided on the pump housing 1. When in use, the hydraulic oil enters the oil chamber 111 through the oil inlet 111a and finally flows out through the oil outlet 111b.

[0034] like Figure 2 As shown, the plunger assembly mainly includes a plunger 21, which is movably arranged in the channel 13. The plunger 21 can reciprocate along the channel 13 under the drive of the oil pressure in the oil chamber 111 to drive the water chamber 121 to absorb and pump water.

[0035] The plunger 21 mainly reciprocates along the axial direction. The axial direction in this embodiment can be understood as the axial direction of the plunger 21, or the axial direction of the plunger pump.

[0036] The pump housing 1 is also provided with two flow channels for water circulation, such as Figure 2As shown, one of the two flow channels constitutes the water inlet channel 3 and the other constitutes the water outlet channel 4.

[0037] Combine Figure 5 As shown, the sealing structure provided in this embodiment is arranged between the channel 13 and the outer peripheral wall of the plunger 21 , and the sealing structure mainly includes a first sealing member 81 , a second sealing member 82 and a leakage space 83 .

[0038] The first seal 81 and the second seal 82 are axially spaced apart in the passage 13, i.e., there is a certain distance in the axial direction between the first seal 81 and the second seal 82. In addition, the first seal 81 and the second seal 82 are both sleeved around the outer peripheral wall of the plunger 21 to achieve a seal between the outer peripheral wall of the plunger 21 and the inner peripheral wall of the passage 13.

[0039] The leakage space 83 is located at the interval between the first sealing member 81 and the second sealing member 82 ; the plunger 21 is at least partially exposed in the leakage space 83 , and the leakage space 83 is communicated with the water inlet channel 3 of the plunger pump.

[0040] The discharge space 83 is mainly used as a pressure relief space. It can be understood that when the plunger 21 is pumping water, it will continuously squeeze into the water chamber 121 to squeeze the water in the water chamber 121. In this way, the water pressure in the water chamber 121 will increase significantly to form high-pressure water. If the sealing structure between the plunger 21 and the channel 13 is not tightly sealed, the high-pressure water formed in the water chamber 121 will flow into the oil chamber 111 through the loose seal. Since the water in the water chamber has a higher water pressure, the pressure of the high-pressure water will affect the action of the reversing mechanism 22 in the oil chamber 111, thereby causing the entire plunger pump to malfunction and fail to work normally.

[0041] When the sealing structure provided by this embodiment is adopted, even if the first sealing component 81 is not sealed tightly and leakage occurs at the sealing point, the leaked high-pressure water will flow into the leakage space 83, and the leakage space 83 is connected to the water inlet channel 3, so the internal water pressure thereof is basically similar to the water pressure in the water inlet channel 3, and the water pressure will not be very high. Therefore, at this time, the high-pressure water leaked at the sealing position of the first sealing component 81 enters the pressure relief space and is relieved, and the water pressure is greatly reduced. Therefore, the high-pressure water will not enter the oil chamber 111 and affect the action of the reversing mechanism 22 in the oil chamber 111.

[0042] In addition, it can be understood that because the water pressure of the leaked high-pressure water decreases after entering the leakage space 83, the impact on the second sealing member 82 will be reduced at this time, thereby increasing the service life of the second sealing member 82.

[0043] Finally, connecting the leakage space 83 with the water inlet channel 3 can not only relieve the pressure of the leaked high-pressure water, but also allow part of the water in the water inlet channel 3 to enter the leakage space 83, so that the entering water contacts the peripheral wall of the plunger 21. In this way, the piston can be cooled by the entering water, and the entering water can also play a certain lubricating role on the peripheral wall of the piston.

[0044] In some embodiments, the leakage space 83 is an annular space and surrounds the outer circumference of the plunger 21, that is, the annular space is circumferentially around the plunger 21, so that any water leakage caused by poor sealing at various positions of the first sealing member 81 can flow into the leakage space 83.

[0045] like Figure 3 As shown, in order to achieve the connection between the leakage space 83 and the water inlet channel 3, in this embodiment, a leakage channel 831 is opened in the pump housing 1, one end of the leakage channel 13 is connected to the water inlet channel 3, and the other end is connected to the leakage space 83, so that the leakage space 83 is connected to the water inlet channel 3 of the plunger pump through the leakage channel 831.

[0046] In some embodiments, since the first sealing member 81 is directly impacted by the high-pressure water in the water cavity 121, in order to improve its sealing effect, Figure 5 As shown, the first sealing member 81 is preferably a combined sealing ring, comprising a support ring 811, a main water seal 812, and a baffle 813, which are sequentially abutted or fixed along the axial direction. The three are sequentially fixed or abutted to form a combined sealing ring; wherein the support ring 811 is located on the side close to the water cavity 121, the baffle 813 is located on the side away from the water cavity 121, and the main water seal 812 (i.e., the main sealing ring) is located between the two; the support ring 811 plays a role in supporting the main water seal 812, and its function is similar to the skeleton of the main water seal 812; and the baffle 813 is used to resist the main water seal 812 on the side away from the water cavity 121. The main water seal 812 can be a sealing ring with a U-shaped or V-shaped cross-section. The entire combined sealing ring is fixed in the channel 13 and is inserted into the plunger 21.

[0047] The above-mentioned combined sealing ring has been extensively described and used in some existing fluid equipment, and will not be described in detail here.

[0048] The second sealing member 82 may be a sealing ring, for example, an O-ring, a lip-shaped sealing ring, a U-shaped sealing ring, etc., which are not specifically limited here.

[0049] Example 2

[0050] Combine Figure 1-5As shown, this embodiment provides a plunger pump based on embodiment 1. The plunger pump provided in this embodiment is a hydraulic direct-drive plunger pump, that is, a pump that uses hydraulic pressure as a power source to push the plunger 21 to achieve water pumping action, for example, hydraulic pressure is provided by hydraulic oil.

[0051] like Figure 1 and Figure 2 As shown, the plunger pump provided in this embodiment includes a pump housing 1 and a plunger assembly. The pump housing 1 is provided with an oil chamber 111 , a water chamber 121 , and a channel 13 located between the water chamber 121 and the oil chamber 111 .

[0052] In some embodiments, the specific structure of the pump housing 1 is that the pump housing 1 includes a main housing 11 and end housings 12 provided at both ends of the main housing 11 .

[0053] like Figure 2 As shown, in this embodiment, the water chambers 121 include two, and along the axial direction, the two water chambers 121 are symmetrically arranged on both sides of the oil chamber 111. The axial direction claimed in this embodiment can be understood as the axial direction of the plunger 21.

[0054] It is understandable that the passage 13 is provided between the two water chambers 121 and the oil chamber 111 . When the plunger assembly is removed, the oil chamber 111 and the water chamber 121 are communicated via the passage 13 .

[0055] In some embodiments, the two water chambers 121 are respectively disposed in the two end shells 12 , and the oil passage is disposed in the main shell 11 .

[0056] The plunger assembly includes a plunger 21 and a reversing mechanism 22. The plunger 21 is movably arranged in the channel 13. It can reciprocate along the channel 13 under the drive of the oil pressure in the oil chamber 111, and its two ends can be inserted into the corresponding water chamber 121 when the plunger 21 moves to drive the water chamber 121 to absorb and pump water.

[0057] Specifically, Figure 2 Taking the perspective shown as an example, when the plunger 21 is pushed to the left by the hydraulic oil, the left end of the plunger 21 will continuously insert into the water chamber 121 on the left, thereby squeezing the water in the water chamber 121 on the left, so that the water in the water chamber 121 on the left is pressed out, that is, the aforementioned water pumping; at the same time, the right end of the plunger 21 will continuously be drawn out from the water chamber 121 on the right to the left. As the right end of the plunger 21 is continuously drawn out, the pressure in the water chamber 121 on the right gradually decreases to form a negative pressure, so that the water chamber 121 on the right starts to absorb water, waiting for the next action of the plunger 21; this cycle is repeated, thereby forming an alternating reciprocating action of one water chamber 121 pumping water and the other water chamber 121 absorbing water, thereby realizing the water pumping function of the plunger pump.

[0058] The reversing mechanism 22 in the plunger assembly is mainly used to achieve the reversing of the action of the plunger 21. Specifically, the plunger 21 can move back and forth axially between the left and right dead point positions. When in use, hydraulic oil is injected into the oil chamber 111 in the pump housing 1, and the plunger assembly is pushed to one side under the pressure of the hydraulic oil. When the plunger 21 moves to the dead point position on that side, the reversing mechanism 22 inside the plunger assembly completes the reversal, so that the hydraulic oil pushes the plunger assembly to the other dead point position. This cycle is repeated, pushing the plunger assembly to move back and forth between the two dead point positions, thereby squeezing the water in the water chamber 121 to achieve water pumping.

[0059] This type of reversing mechanism 22 has been widely used and described in existing hydraulic direct-drive plunger pumps, and this embodiment does not involve improvements to the reversing mechanism 22 , so no further details will be given here.

[0060] like Figure 2 As shown, the pump housing 1 is further provided with two flow channels for water circulation, one of which is marked as a water inlet channel 3 and the other as a water outlet channel 4.

[0061] The water inlet channel 3 has a water inlet 30, and the water outlet channel 4 has a water outlet 40; the two ends of the two channels (i.e., the water inlet channel 3 and the water outlet channel 4) are respectively connected to the two water chambers 121; thus, the water source to be pumped enters through the water inlet 30, is sucked into the water chamber 121 which is performing the water suction action along the water inlet channel 3; when the water chamber 121 is pumping water, the water in the water chamber 121 is pumped into the water outlet channel 4 and is finally discharged through the water outlet 40.

[0062] It can be understood that the water inlet 30 is equivalent to the water inlet end of the entire plunger pump, and the water outlet 40 is equivalent to the water outlet end of the plunger pump.

[0063] A sealing structure is provided between the channel 13 and the outer peripheral wall of the plunger 21. The sealing structure here adopts the sealing structure provided in Example 1. Please refer to the description of Example 1 and will not be repeated here.

[0064] In some embodiments, the specific structure of the channel 13 can be as follows: Figure 2 As shown, a partition 9 is provided between the oil chamber 111 and the water chamber 121 to separate the oil chamber 111 and the water chamber 121 , and a channel 13 is opened on the partition and a part of the inner peripheral wall of the water chamber 121 .

[0065] Accordingly, the first seal 81 is mounted on the portion of the channel 13 located on the end shell 12, while the second seal 82 is mounted on the partition. The space enclosed between the partition and the end shell 12 constitutes the aforementioned leakage space 83; and the leakage channel 831 is opened in the end shell 12.

[0066] In addition, in this embodiment, both flow channels include a main channel and a branch flow channel 5, wherein, in some embodiments, the main channel is arranged in the main shell 11 and extends axially along the main shell 11; the branch flow channel 5 is arranged on the end shell 12, one end of which is connected to the water cavity 121 on the same side as it, and the other end is connected to the main channel.

[0067] It can be understood that, in this embodiment, both the water inlet flow channel 3 and the water outlet flow channel 4 are formed with branch flow channels 5 on the end shell 12 , and therefore, the two flow channels have a total of four branch flow channels 5 .

[0068] In order to distinguish, Figure 2 As shown, in this embodiment, the main channel of the water inlet channel 3 is recorded as the water inlet main channel 31 , and the main channel of the water outlet channel 4 is recorded as the water outlet main channel 41 ; the water inlet 30 is provided on the water inlet main channel 31 .

[0069] In some embodiments, the main water inlet channel 31 and the main water outlet channel 41 are provided on either side of the main housing 11. Furthermore, in this embodiment, two one-way valves are provided at both ends of the water inlet channel 3 and the water outlet channel 4. For example, a one-way valve is provided on each branch channel 5 to control the opening / closing of the corresponding branch channel 5.

[0070] It can be understood that a one-way valve refers to a valve that can only conduct fluid in one direction, that is, the fluid is only allowed to flow from the water inlet end to the water outlet end of the one-way valve, and the reverse direction is blocked and cannot flow back.

[0071] In some embodiments, each one-way valve can be detachably mounted on the end housing 12. Since the mounting structures of the one-way valves are substantially the same, one of the one-way valves is used as an example for detailed description in the present embodiment.

[0072] Combine Figure 4 As shown, a mounting port 14 for installing a one-way valve is provided on the end shell 12, and the mounting port 14 has a step surface 141. The one-way valve is pressed on the step surface 141 by a clamping member. The clamping member here includes a pressure cap 7 with threads on the outer peripheral wall. For example, in some embodiments, the pressure cap 7 can be a bolt.

[0073] The corresponding installation opening 14 has a threaded section on its peripheral wall that matches the thread of the pressure cap 7 , so that the pressure cap 7 is screwed into the installation opening 14 in a threaded connection manner to press the one-way valve against the step surface 141 to achieve the installation of the one-way valve.

[0074] Conversely, when the one-way valve needs to be removed, it is only necessary to unscrew the pressing cap 7 to remove the one-way valve from the installation opening 14 .

[0075] In order to distinguish, in this embodiment, Figure 2As shown, the two one-way valves located on the water inlet channel 3 are respectively marked as first one-way valves 61, and the two one-way valves located on the water outlet channel 4 are respectively marked as second one-way valves 62.

[0076] The first one-way valve 61 is configured to allow water in the water inlet channel 3 to flow toward the water cavity 121 in one direction, but blocks water from flowing in the opposite direction. That is, the first one-way valve 61 allows water in the main water inlet channel 31 to flow toward the water cavity 121 through the branch channel 5 of the water inlet channel 3, but blocks water from flowing in the opposite direction.

[0077] The second one-way valve 62 is configured to allow water in the water chamber 121 to flow toward the outlet channel 4 in one direction, but to block the flow in the opposite direction. That is, the second one-way valve 62 allows water in the water chamber 121 to flow into the main outlet channel 41 through the branch channel 5 of the outlet channel 4, but to block the flow in the opposite direction.

[0078] In addition, a water outlet hole 71 is provided on the pressure cap 7 of one of the second one-way valves 62, which is connected to the water outlet end of the second one-way valve 62. For example, in this embodiment, Figure 2 The second one-way valve 62 in the upper right corner is provided with a water outlet 71. The water outlet 71 serves as the water outlet 40 of the aforementioned water outlet channel 4, and can also be understood as the water outlet end of the plunger pump.

[0079] In this embodiment, the specific structures of the branch channels 5 are basically the same. The branch channels 5 are roughly L-shaped and mainly include a first channel 51 and a second channel 52 . The installation port 14 is opened at the connection position of the first channel 51 and the second channel 52 .

[0080] In the branch channel 5 of the water inlet channel 3, one end of the first channel 51 is connected to the water chamber 121, and the other end is connected to the water outlet end of the first one-way valve 61; one end of the second channel 52 is connected to the main water inlet channel 31, and the other end is connected to the water inlet end of the first one-way valve 61.

[0081] In the branch flow channel 5 of the outlet flow channel 4, one end of the first flow channel 51 is connected to the water chamber 121, and the other end is connected to the water inlet end of the second one-way valve 62; one end of the second flow channel 52 is connected to the main outlet flow channel 41, and the other end is connected to the water outlet end of the second one-way valve 62.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced within the present invention.

Claims

1. A sealing structure of a hydraulic direct-drive plunger pump, wherein the plunger pump comprises a channel for passing a plunger, wherein the plunger is capable of axially reciprocating motion along the channel, and wherein: The sealing structure includes a first seal, a second seal and a leakage space; the first seal and the second seal are arranged in the channel at intervals along the axial direction and surround the outer peripheral wall of the plunger; the leakage space is located at the interval between the first seal and the second seal, the plunger is at least partially exposed in the leakage space, and the leakage space is connected to the water inlet channel of the plunger pump.

2. The sealing structure of the hydraulic direct drive plunger pump according to claim 1, characterized in that: The leakage space is an annular space and surrounds the outer circumference of the plunger.

3. The sealing structure of the hydraulic direct drive plunger pump according to claim 1, characterized in that: A discharge flow channel is provided in the pump housing of the plunger pump, and the discharge flow space is connected with the water inlet flow channel of the plunger pump through the discharge flow channel.

4. The sealing structure of the hydraulic direct drive plunger pump according to claim 1, characterized in that: The first sealing member is a combined sealing ring, comprising a support ring, a main water seal, and a baffle that are sequentially abutted or fixed along the axial direction.

5. A plunger pump, comprising a pump housing and a plunger assembly, wherein the plunger assembly comprises a plunger, wherein the pump housing is provided with an oil chamber, a water chamber, and a channel between the water chamber and the oil chamber; the plunger is arranged in the channel and can reciprocate along the channel under the drive of the oil pressure in the oil chamber to drive the water chamber to absorb and pump water; the pump housing is further provided with two flow channels for water circulation, wherein one of the two flow channels constitutes a water inlet flow channel and the other constitutes a water outlet flow channel; a sealing structure is provided between the channel and the outer peripheral wall of the plunger, characterized in that, The sealing structure adopts the sealing structure of the hydraulic direct-drive plunger pump as described in any one of claims 1 to 4.

6. The plunger pump according to claim 5, characterized in that The pump housing includes a main housing and end housings provided at both ends of the main housing. The flow channel is at least partially located on the end housing to form a branch flow channel. A one-way valve for controlling the on / off of the branch flow channel can also be detachably installed on the end housing.

7. The plunger pump according to claim 6, characterized in that The end shell is provided with an installation port for installing the one-way valve, the installation port has a step surface, and the one-way valve is pressed on the step surface by a pressing component.

8. The plunger pump according to claim 7, characterized in that The pressing member is threadedly connected to the mounting port.

9. The plunger pump according to claim 6, characterized in that The water cavity includes two groups, and the two groups of water cavities are respectively located on both sides of the oil cavity; the two ends of the flow channel are respectively connected to the two water cavities; the two one-way valves arranged on the water inlet flow channel are recorded as first one-way valves, and the two one-way valves arranged on the water outlet flow channel are recorded as second one-way valves; the first one-way valve is constructed to allow water in the water inlet flow channel to flow to the water cavity in one direction, and the second one-way valve is constructed to allow water in the water cavity to flow to the water outlet flow channel in one direction.

10. The plunger pump according to claim 6, characterized in that The flow channel also includes a main flow channel connected to the branch flow channel, and the main flow channels of the two flow channels are respectively located on both sides of the main shell.

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