Plunger pump

Abstract

The invention provides a plunger pump. The plunger pump comprises a driving wheel, a connecting rod, a plunger and a column cylinder. The driving wheel is provided with a driving shaft which is eccentrically arranged relative to the rotation center of the driving wheel; the connecting rod is rotationally connected with the driving shaft and the plunger respectively; therefore, when the driving wheel rotates, the plunger is driven by the connecting rod to move in the column cylinder in a reciprocating mode. The plunger pump further comprises a guide rail crossed with the extending direction of the column cylinder, and the driving wheel can reciprocate along the guide rail. In the working state, the position of the driving wheel is adjusted along the guide rail, and then the moving stroke of the plunger in the column cylinder is changed. Accordingly, flow pulsation can be reduced while the flow is adjusted.

Description

Technical Field

[0001] The present application relates to a plunger pump capable of reducing flow pulsation while regulating the flow. Background Art

[0002] The plunger pump is an important device in the hydraulic system. It relies on the reciprocating motion of the plunger in the cylinder, i.e. the cylinder body, to change the volume of the sealed working chamber to achieve the suction operation of the fluid. The plunger pump has the advantages of high rated pressure, compact structure, high efficiency and convenient flow regulation. It is widely used in high pressure and flow regulation occasions.

[0003] However, common plunger pumps have large flow pulsation when the main shaft speed is low, especially single plunger plunger pumps. Existing plunger pumps can only adjust the flow by adjusting the main shaft speed and then changing the reciprocating frequency of the plunger, but the flow pulsation problem of plunger pumps is not easy to solve when the flow is low.

[0004] Therefore, in the prior art, there is a technical problem of how to reduce flow pulsation while regulating the flow rate. Summary of the invention

[0005] The purpose of the present application is to provide a plunger pump that can reduce flow pulsation while regulating flow. In order to achieve the above purpose, one scheme of the present application is a plunger pump, comprising a driving wheel, a connecting rod, a plunger, and a column cylinder; the driving wheel has a driving shaft eccentrically arranged relative to its rotation center; the connecting rod is rotatably connected to the driving shaft and the plunger respectively; thus, when the driving wheel rotates, the plunger is driven to reciprocate in the column cylinder via the connecting rod; the plunger pump also includes a guide rail arranged crosswise with the extension direction of the column cylinder, and the driving wheel can reciprocate along the guide rail; in the working state, the position of the driving wheel is adjusted along the guide rail, thereby changing the stroke of the plunger moving in the column cylinder.

[0006] According to the aforementioned technical solution, by adjusting the position of the driving wheel instead of its rotation speed, the stroke of the plunger in the column cylinder can be changed, thereby adjusting the flow of the plunger pump and avoiding the flow pulsation caused by the rotation speed change.

[0007] In a preferred embodiment, the guide rail is arranged perpendicular to the extension direction of the column cylinder.

[0008] In a preferred embodiment, the extension direction of the column cylinder is the horizontal direction, and the direction perpendicular to the horizontal direction is the up-down direction; the guide rail is arranged in such a manner that the closer it is to the plunger in the horizontal direction, the farther it is from the plunger in the up-down direction.

[0009] According to the above technical solution, the idle stroke interval in the column cylinder can be reduced.

[0010] In a preferred embodiment, the guide rail is arc-shaped.

[0011] In a preferred embodiment, the vertical distance from the rotation center of the driving wheel to the axis of the plunger is x, and the stroke of the reciprocating movement of the plunger is L. A mapping relationship between the vertical distance x and the stroke L is established in advance, and the vertical distance x can be adjusted accordingly according to the required stroke L.

[0012] According to the aforementioned technical solution, establishing a mapping relationship facilitates corresponding adjustment of the vertical distance x according to the required travel L, thereby increasing control convenience.

[0013] In a preferred embodiment, assuming that the eccentricity of the drive shaft relative to the rotation center of the drive wheel is a, and the distance between the connecting rod and the connection point with the drive shaft and the plunger is b, then formula (1) is satisfied:

[0014]

[0015] In a preferred embodiment, assuming that the distance between the position of the plunger farthest from the driving wheel and the rotation center of the driving wheel in the extension direction of the cylinder is M, then formula (2) is satisfied:

[0016]

[0017] According to the above technical solution, the position of the driving wheel can be adjusted while ensuring that the rightmost position of the plunger stroke interval is the same or similar, thereby reducing the idle stroke interval.

[0018] In a preferred embodiment, a phase adjustment motor is also included; the phase adjustment motor drives the driving wheel to reciprocate along the guide rail via a screw nut mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the present application, the following description and drawings of the present application are described and illustrated. Obviously, the drawings in the following description only illustrate certain aspects of some exemplary embodiments of the present application, and it is possible for a person of ordinary skill in the art to obtain other drawings based on these drawings without creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure of the plunger pump.

[0021] Figure 2 This is a schematic diagram of the travel when the drive wheel is at the top.

[0022] Figure 3 This is a schematic diagram of the travel when the drive wheel is located at the bottom.

[0023] Figure 4 This is a schematic diagram of the relationship between the position of the drive wheel and the stroke of the plunger.

[0024] Figure 5 It is a schematic diagram of the structure using an arc guide rail.

[0025] Description of reference numerals:

[0026] 11 Column Cylinder

[0027] 12 Plunger

[0028] 121 Connection Points

[0029] 13 Sealing ring

[0030] 14 Inlet check valve

[0031] 15 Outlet check valve

[0032] 16 fluid inlet

[0033] 17 Fluid outlet

[0034] 2 Connecting rod

[0035] 3 Drive wheels

[0036] 30 Spindle

[0037] 31 First guide slide

[0038] 32 Second guide slide

[0039] 33 Drive shaft

[0040] 34 Fixed plate

[0041] 4 Base

[0042] 41 First rail

[0043] 42 Second rail

[0044] 43 Lead Screw

[0045] 44 Phase Drive Motor DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present application are described in detail below with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is by no means intended to limit the present application and its application or use. The present application can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present application thorough and complete and to fully express the scope of the present application to those skilled in the art. It should be noted that unless otherwise stated, the relative arrangement of the components and steps, numerical expressions, and numerical values, etc., described in these embodiments should be interpreted as being merely exemplary, rather than as limitations.

[0047] The words “include” or “comprising” and the like used in this application mean that the elements preceding the words include the elements listed after the words, and do not exclude the possibility of also including other elements.

[0048] All terms (including technical terms or scientific terms) used in this application have the same meaning as those understood by ordinary technicians in the field to which this application belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined in this article.

[0049] Components not described in detail in this section, parameters such as specific models of components, relationships between components, and control circuits may be considered as technologies, methods, and equipment known to ordinary technicians in the relevant fields, but in appropriate circumstances, such technologies, methods, and equipment should be considered as part of the specification.

[0050] Overall structure

[0051] First refer to Figure 1-3 The overall structure of the plunger pump of the present application is described. Figure 1 This is the overall structural diagram of the plunger pump. Figure 2 is a schematic diagram of the travel when the driving wheel 3 is located at the top, Figure 3 It is a schematic diagram of the travel when the driving wheel 3 is located at the bottom.

[0052] See also Figure 1 The plunger pump of the present application is used for pumping fluid, and comprises a column cylinder 11, a plunger 12 located in the column cylinder 11, an inlet check valve 14, an outlet check valve 15, a fluid inlet 16, and a fluid outlet 17.

[0053] The plunger 12 is provided with a sealing ring 13 so as to maintain a seal with the inner wall of the cylinder 11 when the plunger 12 moves in the cylinder 11. Thus, a fluid containing area is formed on the side of the cylinder 11 near the fluid inlet 16.

[0054] When the plunger 12 moves in the column cylinder 11 toward the side away from the fluid inlet 16, the inlet one-way valve 14 is opened and the outlet one-way valve 15 is closed, and the external fluid flows into the fluid containing area in the column cylinder 11 from the fluid inlet 16. When the plunger 12 moves toward the side close to the fluid inlet 16, the inlet one-way valve 14 is closed and the outlet one-way valve 15 is opened, so that the fluid in the fluid containing area flows out from the fluid outlet 17, thereby realizing the suction function of the external fluid.

[0055] The present application also includes a driving wheel 3 and a connecting rod 2. The driving wheel 3 has a driving shaft 33 eccentrically arranged relative to the main shaft 30 at its rotation center; the connecting rod 2 is rotatably connected to the driving shaft 33 and the plunger 12, such as being hinged; thus, when the driving wheel 3 rotates, the plunger 12 is driven to reciprocate in the column cylinder 11 via the connecting rod 2.

[0056] For the sake of convenience, the extension direction of the column cylinder 11 is the horizontal direction, and the direction perpendicular to the horizontal direction is the up-down direction. In the horizontal direction, the side close to the fluid inlet 16 is the right, and the opposite is the left. In the up-down direction, the side of the driving wheel 3 relative to the base 4 is the top, and the opposite is the bottom.

[0057] The driving wheel 3 shown in the figure is located at the lower left side of the plunger 12. It can be understood that this is only an example. The driving wheel 3 can also be located at the upper left side of the plunger 12 or other positions, that is, the rotation center of the driving wheel 3 can also be set above the axis of the plunger 12, as long as it can drive the plunger 12 to move reciprocatingly. Here, only the lower left side of the driving wheel 3 shown in the figure is used as an example for explanation.

[0058] In the prior art, common plunger pumps have large flow pulsation when the main shaft 30 rotates at a low speed, especially single-plunger plunger pumps. The existing plunger pumps can only adjust the flow by adjusting the speed of the main shaft 30 and then changing the reciprocating frequency of the plunger 12. When the flow is small, the flow pulsation problem of the plunger pump is not easy to solve.

[0059] To this end, the plunger pump of the present invention changes the volume of the plunger pump by changing the stroke of the plunger 12, thereby achieving flow regulation without changing the rotation speed of the main shaft 30, that is, without changing the reciprocating frequency of the plunger 12, thereby improving the stability of the flow output.

[0060] Continue to view Figure 1The plunger pump of the present application further includes guide rails arranged crosswise with the extension direction of the column cylinder 11, such as the first guide rail 41 and the second guide rail 42 shown in the figure, and the driving wheel 3 is slidably connected to the first guide rail 41 and the second guide rail 42 via the first guide slider 31 and the second guide slider 32, respectively, so that the driving wheel 3 can reciprocate up and down along the first guide rail 41 and the second guide rail 42 under the drive of the phase driving motor 44. Among them, the driving wheel 3 is connected to the first guide slider 31 and the second guide slider 32 via the fixing plate 34. The first guide rail 41 and the second guide rail 42 are installed on the base 4.

[0061] It is understood that the actual number of guide rails can be one or more, and only two guide rails are used as an example for illustration. Figure 1 As shown, it is arranged perpendicularly to the extension direction of the column cylinder 11, and can also be arranged obliquely or in a curve such as an arc, which will be described later.

[0062] Figure 2 The diagram is a schematic diagram when the driving wheel 3 is located at a lower position. The dashed line indicated by the arrow in the figure shows the leftmost part of the stroke of the plunger 12, and the distance between the dashed line and the rightmost part of the stroke of the plunger 12 is the stroke L.

[0063] Figure 3 The diagram is a schematic diagram of the driving wheel 3 being in an upper position. The dashed line indicated by the arrow in the figure shows the leftmost part of the stroke of the plunger 12, and the distance between the dashed line and the rightmost part of the stroke of the plunger 12 is the stroke L.

[0064] like Figure 2 , Figure 3 As shown, the moving range of the plunger 12 when the driving wheel 3 is in the lower position is closer to the left side of the cylinder 11 than the moving range of the plunger 12 when the driving wheel 3 is in the upper position.

[0065] Next, combine Figure 4 The relationship between the position of the driving wheel 3 and the corresponding stroke L of the plunger 12 will be described. Figure 4 It is a principle diagram of the relationship between the position of the driving wheel 3 and the stroke of the plunger 12.

[0066] like Figure 4 As shown, let the vertical distance from the rotation center of the driving wheel 3 to the axis of the plunger 12 be x, that is, when the extension direction of the column cylinder 11 is the horizontal direction, the upper and lower spacing from the rotation center of the driving wheel 3 to the horizontal center axis of the plunger 12 is x; let the stroke of the reciprocating movement of the plunger 12 in the column cylinder 11 be L, and establish a mapping relationship between the vertical distance x and the stroke L in advance, so that the vertical distance x can be adjusted accordingly according to the required stroke L.

[0067] As a preferred mode, let the eccentricity of the driving shaft 33 relative to the rotation center of the driving wheel 3 be a, the distance between the connecting rod 2 and the connecting point 121 of the driving shaft 33 and the plunger 12 be b, and let the distance Lx from the rotation center of the driving wheel 3 to the connecting point 121 of the plunger 12 and the connecting rod 2 in the extension direction of the column cylinder 11 be θ, and the angle between the axis of the connecting rod 2 and the plunger 12 be θ. In this embodiment, the extension direction of the column cylinder 11 is the horizontal direction, then Lx is the horizontal distance from the rotation center of the driving wheel 3 to the connecting point 121 of the plunger 12 and the connecting rod 2, and θ is the angle between the connecting rod 2 and the horizontal line.

[0068] When the plunger 12 moves to the rightmost side, the main shaft 30, the driving shaft 33 and the connecting rod 2 of the driving wheel 3 are located on a straight line, and the driving shaft 33 and the connecting rod 2 are located on the upper right side of the main shaft 30. The eccentricity of the connecting rod 2 and the driving shaft 33 together constitutes the hypotenuse of a triangle. According to trigonometric functions, it can be known that:

[0069] L1=(a+b)×cosθ1

[0070]

[0071] At this time, the angle between the connecting rod 2 and the horizontal line is θ1, and the horizontal distance from the rotation center of the driving wheel 3 to the connection point 121 of the plunger 12 and the connecting rod 2 is L1.

[0072] When the plunger 12 moves to the leftmost position, the main shaft 30 of the driving wheel 3, the driving shaft 33 and the connecting rod 2 are located in a straight line, and the driving shaft 33 is located at the lower left side of the main shaft 30. The connecting rod 2 passes through the rotation center of the driving wheel 3. The connecting rod 2 minus the eccentricity of the driving shaft 33 constitutes the hypotenuse of the triangle. According to trigonometric functions, it can be known that:

[0073] L2=(ba)×cosθ2

[0074]

[0075] At this time, the angle between the connecting rod 2 and the horizontal line is θ2, and the horizontal distance from the rotation center of the driving wheel 3 to the connection point 121 of the plunger 12 and the connecting rod 2 is L2.

[0076] It can be seen that the stroke of the plunger 12 is:

[0077] L=L1-L2

[0078] Combined with trigonometric isochronous formulas:

[0079] sin 2 θ+cos 2 θ=1

[0080] Combining the above formulas, we get formula (1):

[0081]

[0082] This formula can be used to deduce the range of x:

[0083] x≤ba

[0084] The derivative of the combined formula (1) with respect to x yields:

[0085]

[0086] Because a+b>ba, so in the range of x≤ba, L ′ ≥0, that is, as x increases, L increases. In other words, in this embodiment, the lower the driving wheel 3 is, the larger the stroke L of the plunger 12 is. In this way, without changing the rotation speed of the driving wheel 3, by adjusting the up and down position of the driving wheel 3, the size of the stroke L of the plunger 12 can be changed, thereby achieving the adjustment of the flow rate of the plunger pump.

[0087] In summary, the mapping relationship between the stroke L of the plunger 12 and the vertical distance x can be obtained through the above formula (1). Under the premise that the rotation speed of the driving wheel 3 and the frequency of the plunger 12 remain unchanged, the change of the pumping flow rate of the plunger pump can be achieved by adjusting the vertical distance x.

[0088] Curved guide rail

[0089] Next, combine Figure 5 The preferred embodiments of the present application are described. Figure 5 It is a schematic diagram of the structure using an arc guide rail.

[0090] As mentioned above, when the driving wheel 3 is lower, that is, the vertical distance x is larger, the moving range of the plunger 12 is at the left side of the column cylinder 11, and when the driving wheel 3 is higher, that is, the vertical distance x is smaller, the moving range of the plunger 12 is at the right side of the column cylinder 11. In this way, the axial length, that is, the horizontal length, of the plunger 12 and the column cylinder 11 needs to be relatively long to achieve the desired function.

[0091] When the active range of the plunger 12 is on the left side, there will be a large empty travel range on the right side of the column cylinder 11. When the column cylinder 11 is running at a high speed, this cavity will increase the risk of air blockage and reduce the volumetric efficiency. In addition, the column cylinder 11 and the plunger 12 usually require high-precision processing methods such as grinding to be processed, and the increase in the length of the column cylinder 11 will also increase the processing cost.

[0092] In order to reduce processing costs and improve volumetric efficiency when the vertical distance x increases, phase adjustment mechanisms such as guide rails (first guide rails 41, second guide rails 42) and lead screws 43 can be set to be inclined at a certain angle to the axial direction of the plunger 12.

[0093] Therefore, as a preferred mode, the guide rails (first guide rail 41, second guide rail 42) are arranged in such a way that the closer they are to the plunger 12 in the horizontal direction, the farther they are from the plunger 12 in the vertical direction. As mentioned above, the guide rails can be arranged obliquely or in a curved shape such as an arc. For the sake of convenience, only the arc shown in the figure is used as an example for explanation.

[0094] In this way, when the driving wheel 3 moves downward, that is, the vertical distance x increases, the horizontal distance from the rotation center of the driving wheel 3 to the fluid inlet 16 is reduced, so that the moving range of the plunger 12 is further to the right in the column cylinder 11, thereby reducing the idle stroke range.

[0095] Further preferably, when the vertical distances x are different, the positions of the plunger 12 when it moves to the rightmost side are ensured to be the same or close.

[0096] like Figure 5 As shown, assume that the distance between the side of the plunger 12 farthest from the driving wheel 3, i.e., the rightmost position, and the rotation center of the driving wheel 3 in the extension direction of the cylinder 11 is M. Then, at the rightmost position, the main shaft 30, the driving shaft 33, and the connecting rod 2 of the driving wheel 3 are located on a straight line, and the driving shaft 33 and the connecting rod 2 are located on the upper right side of the main shaft 30. The eccentricity of the connecting rod 2 and the driving shaft 33 together constitutes the hypotenuse of a triangle, and it can be obtained that:

[0097] M=(a+b)cosθ1

[0098] Substitution

[0099] The relationship between M and x satisfies formula (2):

[0100]

[0101] By establishing the mapping relationship between M and the vertical distance x according to formula (2), the curve equation of the guide rail (first guide rail 41, second guide rail 42) can be determined, that is, different horizontal offsets correspond to different vertical distances x. After the curve style of the guide rail (first guide rail 41, second guide rail 42) is established, during operation, the corresponding vertical distance x can be adjusted according to the required stroke L according to the mapping relationship between the stroke L and the vertical distance x established by formula (1), and the driving wheel 3 can be adjusted to the position corresponding to x through the phase drive motor 44.

[0102] In summary, the plunger pump described in the present application changes the stroke L of the plunger 12 without changing the frequency of the plunger 12 by adjusting the position of the driving wheel 3 instead of adjusting its rotational speed, thereby changing the size of the fluid storage area in the column cylinder 11, that is, changing the volumetric efficiency, thereby adjusting the flow rate output by the plunger pump, avoiding flow pulsation caused by changes in rotational speed, and is particularly suitable for application scenarios with low flow rates, and is more likely to ensure the stability of the flow rate of the plunger pump. Furthermore, a mapping relationship between the stroke L and the position of the driving wheel 3, that is, the vertical distance x, is established in advance, and the position that needs to be adjusted can be quickly determined according to the required stroke L, with a simple structure and convenient control.

[0103] It should be understood that the specific embodiments described above are only used to explain the present application, and the protection scope of the present application is not limited thereto. Any technical personnel familiar with the technical field can make changes, substitutions, and combinations within the technical scope disclosed in the present application according to the technical solution and inventive concept of the present application, which should be covered by the protection scope of the present application.

Claims

1. A plunger pump, characterized in that: It includes driving wheel, connecting rod, plunger and cylinder; The driving wheel is provided with a driving shaft eccentrically arranged relative to its rotation center; the connecting rod is rotatably connected to the driving shaft and the plunger respectively; thus, when the driving wheel rotates, the plunger is driven to reciprocate in the column cylinder via the connecting rod; The plunger pump further comprises a guide rail arranged to intersect with the extension direction of the column cylinder, and the driving wheel can move along the guide rail; In the working state, the position of the driving wheel is adjusted along the guide rail, thereby changing the travel of the plunger in the column cylinder.

2. The plunger pump according to claim 1, characterized in that: The guide rail is arranged in a manner perpendicular to the extending direction of the column cylinder.

3. The plunger pump according to claim 1, characterized in that: The extending direction of the column cylinder is taken as the horizontal direction, and the direction perpendicular to the horizontal direction is the up-down direction; The guide rail is provided so as to be closer to the plunger in the horizontal direction and farther away from the plunger in the vertical direction.

4. The plunger pump according to claim 3, characterized in that: The guide rail is arc-shaped.

5. The plunger pump according to claim 1 or 2, characterized in that: Assuming that the vertical distance from the rotation center of the driving wheel to the axis of the plunger is x, and the stroke of the reciprocating movement of the plunger is L, a mapping relationship between the vertical distance x and the stroke L is established in advance, and the vertical distance x can be adjusted accordingly according to the required stroke L.

6. The plunger pump according to claim 5, characterized in that: Assuming that the eccentricity of the drive shaft relative to the rotation center of the drive wheel is a, and the distance between the connecting rod and the connection point with the drive shaft and the plunger is b, then equation (1) is satisfied:

7. The plunger pump according to claim 3 or 4, characterized in that: Assuming that the vertical distance from the rotation center of the driving wheel to the axis of the plunger is x, and the stroke of the reciprocating movement of the plunger is L, a mapping relationship between the vertical distance x and the stroke L is established in advance, and the vertical distance x can be adjusted accordingly according to the required stroke L.

8. The plunger pump according to claim 7, characterized in that: Assuming that the eccentricity of the drive shaft relative to the rotation center of the drive wheel is a, and the distance between the connecting rod and the connection point with the drive shaft and the plunger is b, then equation (1) is satisfied:

9. The plunger pump according to claim 8, characterized in that: Assuming that the distance between the position of the plunger farthest from the driving wheel in the stroke and the rotation center of the driving wheel in the extension direction of the cylinder is M, then equation (2) is satisfied:

10. The plunger pump according to claim 1, characterized in that: Also includes a phase adjustment motor; The phase adjustment motor drives the driving wheel to reciprocate along the guide rail via a screw nut mechanism.

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