Pressure-stabilizing and flow-stabilizing delivery pump with pre-pressing function

Abstract

The utility model discloses a pressure-stabilizing and flow-stabilizing delivery pump with a pre-pressing function. The pressure-stabilizing and flow-stabilizing delivery pump comprises two pumping hydraulic cylinders, the two pumping hydraulic cylinders alternately move forwards and backwards to suck materials and push the materials in a pumping mode, the pressure-stabilizing and flow-stabilizing delivery pump further comprises a pre-pressing unit, and the pre-pressing unit is used for pre-pressing the materials after the pumping hydraulic cylinders move backwards to suck the materials and before the pumping hydraulic cylinders push the materials in the pumping mode. And the pumping hydraulic cylinder is driven to advance so as to pre-pressurize the sucked materials.

Description

Technical Field

[0001] This utility model relates to the field of pumping equipment, and in particular to a pressure-stabilizing and flow-stabilizing pump with pre-compression function for pumping liquids, slurries, pastes and paste-like materials. Background Technology

[0002] In projects such as the transportation of paste in mine filling pipelines and the transportation of cement mortar in construction projects, S-tube valve pumps are usually used for transportation, but they have disadvantages such as low transportation efficiency and small transportation flow.

[0003] To address this, patent document CN 106014903 A discloses a dual-cylinder steady-flow conveying pump (patent number: 2016103078026). This prior art eliminates pumping interruptions and maintains stable flow by adding a common pumping process during the alternating pumping transition between the two pumping cylinders. However, since the pressure of the material in the waiting-to-pump cylinder is much lower than the pressure of the material in the conveying pipeline, when both pumping cylinders are simultaneously connected to the conveying pipeline, it is necessary to pressurize to a pressure equal to the pressure of the material in the conveying pipeline. During this pressurization process, due to the elastic deformation of the cylinder body, pumping piston, and feed valve body of the waiting-to-pump cylinder, as well as the mixing of some gas into the pumped material and the intake of air by the feed valve, the volume of the pressurized material decreases, while the volume of the pressurizing chamber increases. This causes the high-pressure material in the conveying pipeline to flow back and enter the pressurizing chamber until its pressure equals the pressure of the material in the conveying pipeline. This inevitably causes pressure fluctuations and interruptions and / or fluctuations in the conveying pipeline. Therefore, the dual-cylinder pressure-stabilizing and flow-stabilizing conveying pump of the above patent can only reduce pressure and flow fluctuations when pumping fluids without compressible gases at low pressure. However, when pumping fluid pastes and slurries containing compressible gases at high pressure, material backflow and pressure fluctuations still occur. Moreover, the higher the conveying pressure, the greater the fluctuations in conveying pressure and flow. The conveying pressure is related to the conveying distance, the conveying flow, the concentration and viscosity of the conveyed material, etc. The longer the conveying distance, the greater the conveying flow, the greater the concentration and viscosity of the conveyed material, the greater the fluctuations in conveying pressure and flow. When the conveying pressure is high, it may even generate violent pulsating pressure.

[0004] This leads to the following main drawbacks and shortcomings:

[0005] 1. Fluctuations in flow rate cause the material in the conveying pipeline to move back and forth. The aggregate in the material will precipitate, aggregate and accumulate under the reciprocating impact, which will lead to an increase in the pipe blockage rate. In particular, the reciprocating impact is stronger in the upward or downward conveying pipeline, making it easier to cause blockage. This greatly affects the reliability of pipeline transportation. Once a blockage occurs, it is not only difficult to determine the blockage point, but also very difficult, labor-intensive and costly to clear the pipeline.

[0006] 2. Pressure fluctuations and pulse pressures can cause fatigue damage and impact fractures to pumping equipment, pipelines, and valves, seriously affecting their service life, reliability, and posing serious safety hazards.

[0007] 3. As the flow rate and distance increase, the flow fluctuation and pulse pressure increase, the pipe blockage rate increases, and the fatigue life decreases. Therefore, the flow rate and distance of the conveying project are severely limited, making it difficult to meet the needs of large flow and long distance conveying projects.

[0008] 4. In some applications, relatively stable pressure or flow rate is required when transporting materials through pipelines. For example, when transporting coal-water slurry fuel to a coal-water slurry boiler, if flow pulsation occurs, the reduced or interrupted flow rate will lead to insufficient fuel supply and interruption of combustion, resulting in boiler shutdown.

[0009] Therefore, it is desirable to have a technical solution to overcome or at least mitigate at least one of the aforementioned defects of the prior art. Utility Model Content

[0010] The purpose of this invention is to provide a solution that overcomes or at least mitigates at least one of the aforementioned defects of the prior art.

[0011] To achieve the above objectives, this utility model provides a pressure-stabilizing and flow-stabilizing conveying pump with pre-pressurization function, comprising: two pumping hydraulic cylinders, which perform material suction and pumping / pushing by alternating forward and backward movement of the two pumping hydraulic cylinders; the pressure-stabilizing and flow-stabilizing conveying pump also includes a pre-pressurization unit, which is used to drive the pumping hydraulic cylinders forward to pre-pressurize the suction material (the material to be pumped) after the pumping hydraulic cylinders have finished retracting to suction material and before pumping / pushing material.

[0012] Preferably, the pre-pressure unit includes a pre-pressure valve group and a pre-pressure pressure source, wherein the pre-pressure valve group controls the opening and closing of the pre-pressure oil circuit between the rear chamber of the pumping hydraulic cylinder and the pre-pressure pressure source.

[0013] Preferably, the pressure-stabilizing and flow-stabilizing delivery pump comprises: a first pumping hydraulic cylinder, a second pumping hydraulic cylinder, a first pumping valve group, a second pumping valve group, a first return oil valve group, a second return oil valve group, a pre-pressure valve group, and a pumping hydraulic pump group.

[0014] The rear chamber of the first pumping hydraulic cylinder is connected to both the first pumping valve group and the first return valve group via oil circuits. The first pumping valve group is also connected to the pumping hydraulic pump group via oil circuits, and the first return valve group is connected to the return oil circuit. The first pumping valve group controls the opening and closing of the oil circuit between the rear chamber of the first pumping hydraulic cylinder and the pumping hydraulic pump group, and the first return valve group controls the opening and closing of the return oil circuit of the rear chamber of the first pumping hydraulic cylinder. The rear chamber of the second pumping hydraulic cylinder is connected to both the second pumping valve group and the second return valve group via oil circuits. The second pumping valve group is connected to the pumping hydraulic pump group via an oil circuit, and the second return valve group is connected to the return oil circuit. The second pumping valve group is used to control the opening and closing of the oil circuit between the rear chamber of the second pumping hydraulic cylinder and the pumping hydraulic pump group, and the second return valve group is used to control the opening and closing of the return oil circuit of the rear chamber of the second pumping hydraulic cylinder. The pre-pressure valve group is connected to the rear chambers of the first pumping hydraulic cylinder and the rear chambers of the second pumping hydraulic cylinder via an oil circuit, and is used to control the opening and closing of the pre-pressure oil circuit of the first pumping hydraulic cylinder and the pre-pressure oil circuit of the second pumping hydraulic cylinder.

[0015] Preferably, the pressure-stabilizing and flow-stabilizing pump includes a connecting chamber valve group. The front chambers of the first pumping hydraulic cylinder and the second pumping hydraulic cylinder are connected in parallel via an oil circuit. The connecting chamber valve group is connected to the parallel connecting chambers of the first pumping hydraulic cylinder and the second pumping hydraulic cylinder via an oil circuit. The connecting chamber valve group is also connected to the return oil circuit. The opening and closing of the return oil circuits of the front chambers of the first pumping hydraulic cylinder and the second pumping hydraulic cylinder are controlled by the connecting chamber valve group.

[0016] Preferably, the pre-pressure valve group includes a pressure control valve connected to the oil circuit of the pre-pressure valve group, which is used to control the pressure of the pre-pressure hydraulic oil flowing into the first pumping hydraulic cylinder and the second pumping hydraulic cylinder, so that the pressure of the pre-pressure hydraulic oil is equal to or close to the pressure of the pumping hydraulic oil in the first pumping hydraulic cylinder and the second pumping hydraulic cylinder.

[0017] Preferably, the pre-pressure valve group includes a pressure control valve connected to the oil circuit of the pre-pressure valve group, which is used to control the pressure of the pre-pressure hydraulic oil flowing into the first pumping hydraulic cylinder and the second pumping hydraulic cylinder, so that the pressure of the pre-pressure hydraulic oil is equal to or close to the pressure of the pumping hydraulic oil in the first pumping hydraulic cylinder and the second pumping hydraulic cylinder.

[0018] Preferably, the pre-pressurization valve group further includes a first cylinder pre-pressurization valve group and a second cylinder pre-pressurization valve group. The first cylinder pre-pressurization valve group is connected to the first pumping hydraulic cylinder through an oil circuit and is used to control the on / off state of the pre-pressurization oil circuit of the first pumping hydraulic cylinder. The second cylinder pre-pressurization valve group is connected to the second pumping hydraulic cylinder through an oil circuit and is used to control the on / off state of the pre-pressurization oil circuit supplied to the second pumping hydraulic cylinder. After the first pumping hydraulic cylinder or the second pumping hydraulic cylinder has finished retracting and sucking up material, the first cylinder pre-pressurization valve group or the second cylinder pre-pressurization valve group is connected to the first pumping hydraulic cylinder or the second pumping hydraulic cylinder waiting to take over pumping, so that the pre-pressurization hydraulic oil can enter the first pumping hydraulic cylinder or the second pumping hydraulic cylinder, drive the first pumping hydraulic cylinder or the second pumping hydraulic cylinder to move forward, and pre-pressurize the material sucked into the first pumping cylinder or the second pumping cylinder through the pumping piston.

[0019] Preferably, the first cylinder pre-pressure valve group further includes a first check valve, and the second cylinder pre-pressure valve group further includes a second cylinder check valve. The first check valve is connected to the output oil line of the first cylinder pre-pressure valve group to prevent hydraulic oil in the first pumping hydraulic cylinder from flowing to the pre-pressure valve group. The second cylinder check valve is connected to the output oil line of the second cylinder pre-pressure valve group to prevent hydraulic oil in the second pumping hydraulic cylinder from flowing to the pre-pressure valve group.

[0020] Preferably, the pressure-stabilizing and flow-stabilizing delivery pump includes an accumulator, which is connected to the pre-pressure valve group through an oil circuit, for storing the hydraulic oil discharged by the pre-pressure hydraulic pump, and for providing pre-pressure hydraulic oil to the first pumping hydraulic cylinder and the second pumping hydraulic cylinder.

[0021] Preferably, the pressure-stabilizing and flow-stabilizing conveying pump includes a second cylinder feed valve, a first cylinder feed valve, a second cylinder discharge valve, and a first cylinder discharge valve. The first cylinder feed valve and the first cylinder discharge valve are directly or indirectly connected to the first pump feeding cylinder. The first cylinder feed valve controls the opening and closing of the first pump feeding cylinder's suction channel, and the first cylinder discharge valve controls the opening and closing of the first pump feeding cylinder's discharge channel.

[0022] The second cylinder feed valve and the second cylinder discharge valve are directly or indirectly connected to the second pumping cylinder. The second cylinder feed valve is used to control the opening and closing of the suction channel of the second pumping cylinder, and the second cylinder discharge valve is used to control the opening and closing of the discharge channel of the second pumping cylinder.

[0023] Preferably, the pressure-stabilizing and flow-stabilizing conveying pump includes a second cylinder feed valve, a first cylinder feed valve, and a two-position three-way discharge valve. The first pumping cylinder is connected to the first cylinder feed valve and is used to control the opening and closing of the material intake channel of the first pumping cylinder.

[0024] The second pumping cylinder is connected to the second cylinder feed valve and is used to control the second pumping cylinder to be directly or indirectly connected to the first pumping cylinder and the second pumping cylinder at the same time. It is used to control the opening and closing of the material discharge channels of the first pumping cylinder and the second pumping cylinder, and can also make the material discharge channels of the first pumping cylinder and the second pumping cylinder open simultaneously or partially open simultaneously.

[0025] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0026] 1. Before the pumping hydraulic oil circuit of the first pumping hydraulic cylinder controlled by the first pumping valve group and the pumping hydraulic oil circuit of the second pumping hydraulic cylinder controlled by the second pumping valve group are simultaneously connected, the pre-pressure valve group first connects to the pumping hydraulic cylinder waiting to be pumped, injects pre-pressure hydraulic oil into it, so that it drives the pumping piston to advance in the corresponding pumping material cylinder, pre-pressurizes the material therein, and raises the pressure of the material therein until it is equal to (or close to) the pressure of the material in the conveying pipeline. In this way, when the pumping hydraulic oil circuit of the first pumping hydraulic cylinder controlled by the first pumping valve group and the second pumping hydraulic cylinder are simultaneously connected, the pumping hydraulic oil circuit of the first pumping hydraulic cylinder controlled by the first pumping valve group and the second pumping hydraulic cylinder are ... When the pumping hydraulic circuit of the second pumping hydraulic cylinder controlled by the valve group is simultaneously connected, the material in the waiting-to-pump material cylinder will no longer be compressed, and the volume of the waiting-to-pump material cylinder and the feed valve will no longer elastically expand. This achieves pressure balance between the material waiting to be pumped and the material in the conveying pipeline. During the subsequent pumping relay transition and switching process of the first and second pumping hydraulic cylinders, the pressure and flow rate of the conveyed material are kept stable (or have low fluctuations), thus achieving no fluctuation (or low fluctuations) in the conveying pressure and flow rate.

[0027] 2. Because it can output materials at a stable flow rate, the materials in the conveying pipeline no longer repeatedly switch between forward and reverse flow. The materials flow at a uniform speed in the conveying pipeline, and the relative positions of each particle remain basically unchanged. This eliminates the sedimentation, aggregation, and accumulation of aggregates caused by the sharp reversal and impact of material flow, reduces the pipe blockage rate, improves the reliability of conveying, and reduces the operation and maintenance costs of pipeline transportation.

[0028] 3. Because it can output materials at a stable pressure without pulse pressure, the pumping equipment, conveying pipelines and valves are almost no longer subjected to alternating stress and impact force, which greatly extends the fatigue life and eliminates the impact brittle fracture damage to the parts.

[0029] 4. Since the material moves forward continuously during the conveying process without any material backflow, the conveying efficiency is not affected by the conveying distance. Unlike S-tube valve conveying pumps, the conveying efficiency will not decrease with the extension of the conveying distance, thus meeting the needs of long-distance pipeline conveying projects.

[0030] 5. Due to its stable conveying flow rate, it has a wider range of applications and can meet the engineering projects in some special fields that have stable requirements for conveying flow rate and conveying pressure. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of a pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to another embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of a pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to another embodiment of the present invention.

[0034] In the diagram: 1 First pumping hydraulic cylinder, 2 Second pumping hydraulic cylinder, 3 First pumping material cylinder, 4 Second pumping material cylinder, 5 Second cylinder feed valve, 6 First cylinder feed valve, 7 Second cylinder discharge valve, 8 First cylinder discharge valve, 9 First pumping valve assembly, 10 First return valve assembly, 11 Second pumping valve assembly, 12 Second return valve assembly, 13 Pumping hydraulic pump assembly, 14 Pre-pressure hydraulic pump, 15 Connecting chamber hydraulic pump, 16 Connecting chamber valve assembly, 17 Accumulator, 18 Pre-pressure valve assembly, 181 First cylinder pre-pressure valve assembly, 182 Second cylinder pre-pressure valve assembly, 183 Pressure control valve, 184 Flow regulating valve, 1811 First check valve, 1821 Second check valve, 19 Two-position three-way discharge valve. Detailed Implementation

[0035] In the accompanying drawings, the same or similar reference numerals are used to denote the same or similar elements or elements having the same or similar functions. The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0036] In the description of this utility model, the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and 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 limiting the scope of protection of this utility model.

[0037] In this invention, the "rear chamber" refers to a chamber that, after being injected with hydraulic oil, can drive the piston forward, thereby compressing and discharging the material from the corresponding material cylinder. Conversely, the "front chamber" refers to a chamber that, after being injected with hydraulic oil, can drive the piston backward, thereby expanding the material cavity of the corresponding material cylinder and drawing in the material.

[0038] In this invention, "forward" refers to the direction in which the piston moves to discharge material from the corresponding material cylinder, and "backward" refers to the direction in which the piston moves to draw material into the corresponding material cylinder.

[0039] In this utility model, the forward or backward movement of the pumping unit, pumping cylinder, pumping oil cylinder, and pumping material cylinder refers to the forward or backward movement of its piston rod or piston, rather than the forward or backward movement of the entire pumping unit, pumping cylinder, pumping oil cylinder, and pumping material cylinder.

[0040] In this invention, the valve assembly includes at least one hydraulic valve, and the pumping hydraulic pump assembly includes at least one hydraulic pump.

[0041] The pumping unit (mainly a pumping cylinder) includes a pumping oil cylinder and a pumping material cylinder. The pumping oil cylinder is divided into a rear chamber and a front chamber by a hydraulic piston installed inside it. The hydraulic piston moves back and forth under the drive of hydraulic oil from drive sources such as the pumping hydraulic subsystem, the pre-pressurization hydraulic subsystem, and the rapid return hydraulic subsystem.

[0042] The pumping cylinder contains a pumping piston or pumping plunger. This piston or plunger is connected to a hydraulic piston via a connecting rod, piston rod, or other structure, and moves integrally in the forward and backward directions. The front end of the pumping piston or plunger directly contacts the material. (Pumping cylinder)

[0043] In this invention, the "rear chamber" refers to a chamber that, after being injected with hydraulic oil, can drive the pumping piston or pumping plunger forward, so that the material chamber of the corresponding material cylinder is pressurized and the material is discharged. Correspondingly, the "front chamber" refers to a chamber that, after being injected with hydraulic oil, can drive the pumping piston or pumping plunger backward, so that the material chamber of the corresponding material cylinder expands and draws in the material.

[0044] In this utility model, "forward" refers to the direction in which the movement of the "pumping piston or pumping plunger" causes the corresponding material cylinder to discharge material, and "reverse" refers to the direction in which the movement of the "pumping piston or pumping plunger" causes the corresponding material cylinder to draw in material.

[0045] In this invention, the pressure control valve can be any suitable form, such as an unloading valve, a relief valve, or a pressure reducing valve, to control the pressure in the corresponding oil circuit or chamber at the required pressure or the required pressure range.

[0046] In this utility model, "connected" or "linked" includes direct connection that is in contact with each other and indirect connection or link that is not in contact with other components.

[0047] Example 1

[0048] Figure 1 A schematic diagram of a pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to a preferred embodiment of the present invention is shown.

[0049] Figure 1 The pressure-stabilizing and flow-stabilizing conveying pump with pre-pressurization function shown includes: a first pumping hydraulic cylinder 1, a second pumping hydraulic cylinder 2, a first pumping material cylinder 3, a second pumping material cylinder 4, a second cylinder feed valve 5, a first cylinder feed valve 6, a second cylinder discharge valve 7, and a first cylinder discharge valve 8.

[0050] The first pumping cylinder 3 and the second pumping cylinder 4 are used to alternately draw in and discharge materials such as liquids, slurries, pastes, and paste-like substances through the reciprocating motion of their internal pistons, thereby achieving continuous pumping of materials. That is, the material is drawn in by the expansion of the chambers of the first pumping cylinder 3 and / or the second pumping cylinder 4, and discharged by the contraction of the chambers of the first pumping cylinder 3 and / or the second pumping cylinder 4.

[0051] Specifically, the first feeding cylinder 3 and the second feeding cylinder 4 draw in material from the inlet and discharge the material to the outlet. The specific forms of the inlet and outlet can be configured as needed. For example, in an optional embodiment, the inlet includes two independent feed branches, each connected to a hopper or feed pipe and each connected to the chamber of its corresponding feeding cylinder. Similarly, the outlet includes two independent discharge branches, each connected to a discharge pipe and each connected to the chamber of its corresponding feeding cylinder.

[0052] In the illustrated alternative embodiment, the feed inlet is a single-unit chamber or single-unit channel, and is connected to the chambers of the second pumping cylinder 4 and the first pumping cylinder 3 via the second cylinder feed valve 5 and the first cylinder feed valve 6, respectively. Similarly, the discharge outlet B is a single-unit chamber or single-unit channel, and is connected to the chambers of the second pumping cylinder 4 and the first pumping cylinder 3 via the second cylinder discharge valve 7 and the first cylinder discharge valve 8, respectively.

[0053] The first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are used to provide hydraulic driving force to drive the reciprocating motion of the pistons of the first pumping cylinder 3 and the second pumping cylinder 4.

[0054] The second cylinder feed valve 5, the first cylinder feed valve 6, the second cylinder discharge valve 7, and the first cylinder discharge valve 8 are controlled by the control unit according to a preset program.

[0055] Figure 1 The pressure-stabilizing and flow-stabilizing pump with pre-pressure function shown also includes: a first pumping valve group 9, a first return valve group 10, a second pumping valve group 11, a second return valve group 12, a pumping hydraulic pump group 13, a pre-pressure hydraulic pump 14, a connecting chamber hydraulic pump 15, a connecting chamber valve group 16, an accumulator 17, and a pre-pressure valve group 18. The pre-pressure valve group 18 includes a first cylinder pre-pressure valve group 181, a second cylinder pre-pressure valve group 182, and a pressure control valve 183.

[0056] The pumping hydraulic pump unit 13 is used to provide driving force to the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, so that they move back and forth, thereby sucking in and discharging materials.

[0057] The first pumping valve group 9 and the second pumping valve group 11 are located between the pumping hydraulic pump group 13 and the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2, and are used to control the connection and disconnection of the oil circuit between them.

[0058] The first pumping valve group 9, the first return valve group 10, the second pumping valve group 11, and the second return valve group 12 are controlled by the control unit according to a preset program.

[0059] The first return oil valve assembly 10 and the second return oil valve assembly 12 are located between the return oil tank and the front chamber of the first pumping hydraulic cylinder 1 and the front chamber of the second pumping hydraulic cylinder 2, respectively, and are used to control the connection and disconnection of the oil circuit (return oil circuit) between them. When the return oil circuit is connected, the piston in the first pumping hydraulic cylinder 1 or the second pumping hydraulic cylinder 2 is allowed to move backward. When the return oil circuit is disconnected (not connected), the piston in the first pumping hydraulic cylinder 1 or the second pumping hydraulic cylinder 2 is not allowed to move backward.

[0060] It should be noted that connecting or disconnecting the return oil circuit only allows or disallows the piston in the first pumping hydraulic cylinder 1 or the second pumping hydraulic cylinder 2 to move backward. To achieve the backward movement of the piston in the first pumping hydraulic cylinder 1 or the second pumping hydraulic cylinder 2, an additional driving force needs to be applied.

[0061] As shown in the diagram, the front chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are connected via an oil passage (linkage oil passage). Therefore, when the piston of one hydraulic cylinder moves forward, the volume of its front chamber decreases, and the hydraulic oil in this reduced-volume chamber is discharged. The discharged hydraulic oil enters the front chamber of the other hydraulic cylinder through the linkage oil passage, increasing the volume of that front chamber. This, in turn, applies a driving force, causing the piston of the other hydraulic cylinder to move backward. (At this time, a return oil passage is required to allow the piston to move backward.)

[0062] In other words, by setting up a linkage oil circuit to connect the front chamber of the first pumping hydraulic cylinder 1 and the front chamber of the second pumping hydraulic cylinder 2, the linkage between the piston of the first pumping hydraulic cylinder 1 and the piston of the second pumping hydraulic cylinder 2 can be realized: when one piston moves forward, the other piston moves backward; and vice versa.

[0063] The oil in the forward chamber enters the rod chamber of another cylinder through the connecting oil passage, pushing it backward.

[0064] The connecting chamber hydraulic pump 15 is used to supply pressurized oil to the front chamber to drive the pistons of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, causing them to retract.

[0065] The connecting chamber valve group 16 is located between the connecting chamber hydraulic pump 15 and the front cylinder of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, and is used to control the connection and disconnection of their connecting oil circuits.

[0066] Accumulator 17 and pre-pressurization hydraulic pump 14 together provide hydraulic oil for pre-pressurization. Pre-pressurization hydraulic pump 14 charges accumulator 17 (supplying pressurized oil), and accumulator 17 supplies pre-pressurized hydraulic oil. For example, the pump continuously supplies pressurized oil to the supply line and accumulator via a check valve. When the pressure in the supply line is lower than a set value (during pre-pressurization), the accumulator discharges pressurized oil; when it is higher than the set value (during no pre-pressurization), the accumulator is injected with pressurized oil to store energy. When the pressure in the supply line exceeds the maximum value, pressure is released via pressure control valve 183.

[0067] In the diagram, the section within the double-dotted line indicated by number 18 is the pre-pressure valve assembly. This pre-pressure valve assembly 18 controls the connection and disconnection of the pre-pressure oil circuit between the rear chamber of the pumping hydraulic cylinder and the pre-pressure source. Thus, when the pre-pressure oil circuit is open, pre-pressure oil is applied to the corresponding pumping hydraulic cylinder, thereby pre-pressurizing the material within the cylinder. Pre-pressurization refers to pre-pressurizing the material before formal pumping.

[0068] The specific form of the pre-pressure valve assembly 18 is not limited to the form shown in the diagram. It only needs to be able to control the on / off state of the pre-pressure oil circuit. It is understood that the pre-pressure oil circuits of the two pumping hydraulic cylinders will not be connected simultaneously. The pre-pressure valve assembly 18 can be, for example, an electrically controlled valve, a hydraulically controlled valve, a manual valve, etc. When using an electrically controlled valve, a corresponding electronic control unit is needed to control the pre-pressure valve assembly. For example, by combining it with limit switches, the stroke state of the pumping hydraulic cylinder can be determined, and the operation of the pre-pressure valve assembly can be controlled accordingly.

[0069] The pumping hydraulic pump unit 13 includes, for example, two hydraulic pumps.

[0070] Accumulator 17 stores pre-pressurized hydraulic oil and supplies it to the rear chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 to provide pre-pressure. Pre-pressure valve assembly 18 is located between accumulator 17 and the rear chambers of the first and second pumping hydraulic cylinders 1 and 2, and is used to control the opening and closing of the connecting oil circuit. That is, it controls the timing of applying pre-pressure.

[0071] Pressure control valve 183 is connected to the oil inlet circuit of pre-pressurization valve assembly 18 and accumulator 17, and is used to control the maximum pressure of pre-pressurized hydraulic oil. More specifically, pressure control valve 183 is, for example, a pressure relief valve or pressure reducing valve, which relieves or reduces pressure when the pressure in the oil circuit reaches or exceeds the set maximum pressure (during pre-pressurization, the pressure gradually increases as the piston advances), maintaining the pressure at the maximum pressure.

[0072] The input ends of the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 are connected to the accumulator via oil circuits. The output end of the first cylinder pre-pressure valve group 181 is connected to the rear chamber of the first pumping hydraulic cylinder 1 via an oil circuit, and the output end of the second cylinder pre-pressure valve group 182 is connected to the rear chamber of the second pumping hydraulic cylinder 2 via an oil circuit. The first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 may also be equipped with a flow rate regulating device to regulate the flow rate of pre-pressure hydraulic oil entering the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2. This controls the piston movement speed during pre-pressurization.

[0073] The rear chamber of the first pumping hydraulic cylinder 1 is connected to the pre-pressurization oil circuit, as well as the first pumping valve group 9 and the first return oil valve group 10 via oil circuits. This allows for the supply of pressurized oil to the rear chamber of the first pumping hydraulic cylinder 1 (forward discharge) or for draining oil from the rear chamber of the first pumping hydraulic cylinder 1 (reverse suction).

[0074] The rear chamber of the second pumping hydraulic cylinder 2 is connected to the pre-pressurization oil circuit, as well as the second pumping valve group 11 and the second return oil valve group 12 via an oil circuit. This allows for the supply of pressurized oil to the rear chamber of the second pumping hydraulic cylinder 2 (forward discharge) or for draining oil from the rear chamber of the second pumping hydraulic cylinder 2 (reverse suction).

[0075] The first pumping valve group 9 and the second pumping valve group 11 are connected to the pumping hydraulic pump group 13 through an oil circuit.

[0076] The front chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are connected in parallel via an oil circuit. Thus, oil from the front chamber of the advancing hydraulic cylinder enters the rod chamber of the other cylinder through the connecting oil circuit, pushing it backward. The parallel connecting chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are connected to the connecting chamber valve group 16 and the connecting chamber hydraulic pump 15 via an oil circuit.

[0077] The first pumping hydraulic cylinder 1 drives the pumping piston to reciprocate within the first pumping cylinder 3, thereby drawing in and expelling material. The second pumping hydraulic cylinder 2 drives the pumping piston to reciprocate within the second pumping cylinder 4, thereby drawing in and expelling material.

[0078] The second cylinder feed valve 5, the first cylinder feed valve 6, the second cylinder discharge valve 7, and the first cylinder discharge valve 8 are cone-sealed shut-off valves. The first cylinder feed valve 6 and the first cylinder discharge valve 8 are both directly or indirectly connected to the first pumping cylinder 3. The first cylinder feed valve 6 controls the opening and closing of the suction channel of the first pumping cylinder 3, and the first cylinder discharge valve 8 controls the opening and closing of the discharge channel of the first pumping cylinder 3. Similarly, the second cylinder feed valve 5 and the second cylinder discharge valve 7 are both directly or indirectly connected to the second pumping cylinder 4. The second cylinder feed valve 5 controls the opening and closing of the suction channel of the second pumping cylinder 4, and the second cylinder discharge valve 7 controls the opening and closing of the discharge channel of the second pumping cylinder 4.

[0079] Figure 1 The working process of the pressure-stabilizing and flow-stabilizing delivery pump with pre-compression function is as follows:

[0080] Process 1: The first pumping hydraulic cylinder 1 advances to pump, and the second pumping hydraulic cylinder 2 retreats to suck up material.

[0081] The first cylinder's feed valve 6 is closed, and the first cylinder's discharge valve 8 is open. This means that the first pumping hydraulic cylinder 1 advances to pump and discharge the material. The second cylinder's feed valve 5 is open, and the second cylinder's discharge valve 7 is closed. This means that the second pumping hydraulic cylinder 2 retracts to suck up material.

[0082] In process 1, the first pumping valve group 9 is open, the first return valve group 10 is closed, the second pumping valve group 11 is closed, the second return valve group 12 is open, and the connecting chamber valve group 16 is closed. The first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 are closed.

[0083] The hydraulic oil discharged by the pumping hydraulic pump unit 13 enters the rear chamber of the first pumping hydraulic cylinder 1, and the hydraulic oil discharged by the connecting chamber hydraulic pump 15 enters the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2. The first pumping hydraulic cylinder 1 moves forward, causing the first pumping material cylinder 3 to push the material outward. The second pumping hydraulic cylinder 2 moves backward, and the second pumping material cylinder 4 uses negative pressure to suck the material inward.

[0084] Step 2: The first pumping hydraulic cylinder 1 advances and pumps forward, while the second pumping hydraulic cylinder 2 pre-pressurizes.

[0085] When the second pumping hydraulic cylinder 2 has completed its retraction (retracted to its maximum position), the second cylinder feed valve 5 closes, stopping the feeding. At this time, the pressure of the material in the material chamber of the second pumping cylinder 4 is relatively low.

[0086] When the connecting chamber valve group 16 opens and the second return valve group 12 closes, the second pumping hydraulic cylinder 2 stops, and the first pumping hydraulic cylinder 1 continues to advance. The hydraulic oil in the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, as well as the hydraulic oil discharged from the connecting chamber hydraulic pump 15, can flow back to the oil tank through the connecting chamber valve group 16.

[0087] The second cylinder pre-pressure valve group 182 opens, and the hydraulic oil in the accumulator 17 and the hydraulic oil discharged from the pre-pressure hydraulic pump 14 enter the rear chamber of the second pumping hydraulic cylinder 2, causing the second pumping hydraulic cylinder 2 to move forward and pressurize the material in the second pumping material cylinder 4.

[0088] By setting the control pressure of the pressure control valve 183, the pre-pressure of the pre-pressurized hydraulic oil can be made equal to (or similar to) the pressure of the pumped hydraulic oil in the rear chamber of the first pumping hydraulic cylinder 1, thereby making the pressure of the material in the first pumping cylinder 3 and the second pumping cylinder 4 equal to (or similar to) the pressure of the material.

[0089] Step 3: The first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 work together to pump:

[0090] When the first pumping hydraulic cylinder 1 advances to a distance from the end point, the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 close, and the hydraulic oil discharged by the pre-pressure hydraulic pump 14 enters the accumulator 17.

[0091] When the connecting chamber valve group 16 is opened, the second pumping valve group 11 is opened, and the second cylinder discharge valve 7 is opened, the pumping hydraulic pump group 13 is simultaneously connected to the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2, and the hydraulic oil discharged from it can simultaneously enter the rear chamber 1 of the first pumping hydraulic cylinder and the rear chamber of the second pumping hydraulic cylinder 2.

[0092] Step 4: First cylinder discharge valve 8 closed.

[0093] When the discharge valve 7 of the second cylinder is opened, the discharge valve 8 of the first cylinder is closed.

[0094] Step 5: The first pumping hydraulic cylinder 1 retracts to suck up material, and the second pumping hydraulic cylinder 2 advances to pump material.

[0095] After the discharge valve 8 of the first cylinder is completely closed, the feed valve 6 of the first cylinder is opened.

[0096] The second pumping valve group 11 is closed, the second return valve group 12 is open, and the connecting chamber valve group 16 is closed. The hydraulic oil discharged by the pumping hydraulic pump group 13 enters the rear chamber of the second pumping hydraulic cylinder 2, and the hydraulic oil discharged by the connecting chamber hydraulic pump 15 enters the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2. The second pumping hydraulic cylinder 2 moves forward, causing the second pumping material cylinder 4 to push the material outward, and the second pumping hydraulic cylinder 1 moves backward to suck the material inward into the first pumping material cylinder 3.

[0097] Step 6: The second pumping hydraulic cylinder 2 advances and pumps forward, while the first pumping hydraulic cylinder 1 is preloaded.

[0098] When the first pumping hydraulic cylinder 1 has finished retracting, the first cylinder feed valve 6 is closed.

[0099] When the connecting chamber valve group 16 opens and the first return valve group 10 closes, the first pumping hydraulic cylinder 1 stops, and the second pumping hydraulic cylinder 2 continues to advance. The hydraulic oil in the parallel connecting chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, as well as the hydraulic oil discharged from the connecting chamber hydraulic pump 15, can flow back to the oil tank via the connecting chamber valve group 16.

[0100] The first cylinder pre-pressure valve group 181 opens, and the hydraulic oil in the accumulator 17 and the hydraulic oil discharged from the pre-pressure hydraulic pump 14 enter the rear chamber of the first pumping hydraulic cylinder 1, causing the first pumping hydraulic cylinder 1 to move forward and pressurize the material in the first pumping material cylinder 3.

[0101] By setting the pressure of the pressure control valve 183, the pre-pressure of the pre-pressurized hydraulic oil can be made equal to (or similar to) the pressure of the pumped hydraulic oil in the rear chamber of the second pumping hydraulic cylinder 2, thereby making the pressure of the material in the first pumping cylinder 3 and the second pumping cylinder 4 equal to (or similar to) the pressure of the material.

[0102] Step 7: The first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 work together to pump:

[0103] When the second pumping hydraulic cylinder 2 advances to a distance from the end point, the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 close, and the hydraulic oil discharged by the pre-pressure hydraulic pump 14 enters the accumulator 17.

[0104] When the connecting chamber valve group 16 is opened and the first pumping valve group 9 is opened, the first cylinder discharge valve 8 begins to open, and the pumping hydraulic pump group 13 is simultaneously connected to the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2. The hydraulic oil discharged from it can simultaneously enter the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2.

[0105] Step 8: The discharge valve 7 of the second cylinder is closed.

[0106] When the discharge valve 8 of the first cylinder is opened, the discharge valve 7 of the second cylinder is closed.

[0107] By repeating the above steps 1 to 8 in a cyclical manner, continuous pressure and flow stabilization pumping of materials can be achieved.

[0108] In steps 1 and 5, the hydraulic oil discharged by the connecting chamber hydraulic pump 15 enters the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, so that the first pumping hydraulic cylinder 1 or the second pumping hydraulic cylinder 2 can retreat at a faster speed than the second pumping hydraulic cylinder 2 or the first pumping hydraulic cylinder 1.

[0109] When the pre-pressure is exactly equal to the pressure of the high-pressure material in the conveying pipeline, the pressure and flow rate of the conveyed material theoretically remain unchanged, representing an ideal state. However, in practical applications, due to factors such as the sensitivity of the pressure control valve and pressure reducing valve, and the viscosity of the hydraulic oil, the pre-pressure itself may experience small fluctuations, and the pressure of the high-pressure material in the conveying pipeline may also fluctuate slightly, making it difficult to achieve perfect consistency between the two. Therefore, in this invention, the equality of the pre-pressure and the pressure of the high-pressure material in the conveying pipeline does not mean that they are absolutely equal, but rather that the deviation between them is less than or equal to 3%.

[0110] Furthermore, a significant pressure stabilization effect can be achieved when the pre-compression pressure and the pressure of the high-pressure material in the conveying pipeline are similar. For example, experimental verification shows that a good effect can be achieved when the deviation between the two is within 25%. In other words, "similar pressures" in this invention refers to a deviation between the two within 25%. The ratio of the absolute value of the pre-compression pressure minus the pressure of the high-pressure material in the conveying pipeline, divided by the pressure of the high-pressure material in the conveying pipeline, is less than or equal to 25%.

[0111] Example 2

[0112] See Figure 2 The diagram shows a preferred embodiment of the pressure-stabilizing and flow-stabilizing conveying pump with pre-pressure function. This pressure-stabilizing and flow-stabilizing conveying pump with pre-pressure function includes: 1 a first pumping hydraulic cylinder, 2 a second pumping hydraulic cylinder, 3 a first pumping material cylinder, 4 a second pumping material cylinder, 5 a second cylinder feed valve, 6 a first cylinder feed valve, 7 a second cylinder discharge valve, 8 a first cylinder discharge valve, 9 a first pumping valve group, 10 a first return oil valve group, 11 a second pumping valve group, 12 a second return oil valve group, 13 a pumping hydraulic pump group, 14 a pre-pressure hydraulic pump, 15 a connecting chamber hydraulic pump, 16 a connecting chamber valve group, 17 an accumulator, and 18 a pre-pressure valve group. The pre-pressure valve group 18 further includes a first cylinder pre-pressure valve group 181, a second cylinder pre-pressure valve group 182, and a pressure control valve 183. The first cylinder pre-pressure valve group 181 further includes a first check valve 1811, and the second cylinder pre-pressure valve group 182 further includes a second check valve 1821.

[0113] In the figure, the part within the double-dotted line indicated by serial number 18 is the pre-pressure valve group, and the pumping hydraulic pump group 13 includes 2 hydraulic pumps.

[0114] The pre-pressure valve assembly 18 has one pressure oil port, one accumulator port and two output ports. The pressure oil port is connected to the pre-pressure hydraulic pump 14 through an oil circuit, the accumulator port is connected to the accumulator 17 through an oil circuit, and the two output ports are respectively connected to the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 through oil circuits.

[0115] The first check valve 1811 is connected in the oil line from the first cylinder pre-pressure valve group 181 to the first pumping hydraulic cylinder 1, and is used to prevent the hydraulic oil in the first pumping hydraulic cylinder 1 from flowing back to the pre-pressure valve group 181. The second check valve 1821 is connected in the oil line from the second cylinder pre-pressure valve group 182 to the second pumping hydraulic cylinder 2, and is used to prevent the hydraulic oil in the second pumping hydraulic cylinder 2 from flowing back to the pre-pressure valve group 181.

[0116] The two-way cartridge valve inserts in the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 have a flow regulating device for regulating the flow rate of the pre-pressure hydraulic oil entering the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2.

[0117] The pressure control valve 183 is connected to the oil inlet line of the pre-pressure valve group 18 and is used to control the pressure of the pre-pressure hydraulic oil.

[0118] There is only one hydraulic pump in the pumping hydraulic pump unit 13.

[0119] The other parts and workflow are the same as in Example 1.

[0120] Example 3

[0121] See Figure 3 The diagram shows a schematic of a pressure-stabilizing and flow-stabilizing conveying pump with pre-pressure function according to another preferred embodiment of the present invention. This pressure-stabilizing and flow-stabilizing conveying pump with pre-pressure function includes: 1 a first pumping hydraulic cylinder, 2 a second pumping hydraulic cylinder, 3 a first pumping material cylinder, 4 a second pumping material cylinder, 5 a second cylinder feed valve, 6 a first cylinder feed valve, 9 a first pumping valve assembly, 10 a first return oil valve assembly, 11 a second pumping valve assembly, 12 a second return oil valve assembly, 13 a pumping hydraulic pump assembly, 14 a pre-pressure hydraulic pump, 15 a connecting chamber hydraulic pump, 16 a connecting chamber valve assembly, 17 an accumulator, 18 a pre-pressure valve assembly, a first cylinder pre-pressure valve assembly 181, a second cylinder pre-pressure valve assembly 182, a pressure control valve 183, and a two-position three-way discharge valve 19.

[0122] In the diagram, the part within the double-dotted line indicated by number 18 is the pre-pressure valve assembly.

[0123] The pre-pressure valve assembly 18 includes a first cylinder pre-pressure valve assembly 181, a second cylinder pre-pressure valve assembly 182, a pressure control valve 183, and a flow regulating valve 184. The first cylinder pre-pressure valve assembly 181 further includes a first check valve 1811, which is connected to the oil line from the accumulator 17 to the first pumping hydraulic cylinder 1, and is used to prevent hydraulic oil in the first pumping hydraulic cylinder 1 from flowing back into the pre-pressure valve assembly 18. The second cylinder pre-pressure valve assembly 182 further includes a second check valve 1821, which is connected to the oil line from the accumulator 17 to the second pumping hydraulic cylinder 2, and is used to prevent hydraulic oil in the second pumping hydraulic cylinder 2 from flowing back into the pre-pressure valve assembly 18. The accumulator 17 is connected to the pre-pressure valve assembly 18 via an oil line, and is used to store pre-pressure hydraulic oil and provide pre-pressure hydraulic oil to the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2. The pressure control valve 183 is connected to the oil inlet line of the pre-pressure valve assembly 18 and the accumulator 17, and is used to control the maximum pressure of the pre-pressure hydraulic oil. The flow regulating valve 184 is connected to the oil line from the accumulator 17 to the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, and is used to regulate the flow rate of hydraulic oil from the accumulator 17 into the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2.

[0124] The input ends of the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 are connected to the accumulator through an oil circuit. The output end of the first cylinder pre-pressure valve group 181 is connected to the rear chamber of the first pumping hydraulic cylinder 1 through an oil circuit. The output end of the second cylinder pre-pressure valve group 182 is connected to the rear chamber of the second pumping hydraulic cylinder 2 through an oil circuit.

[0125] The rear chamber of the first pumping hydraulic cylinder 1 is connected to the first pumping valve group 9 and the first return valve group 10 via an oil circuit. The rear chamber of the second pumping hydraulic cylinder 2 is connected to the second pumping valve group 11 and the second return valve group 12 via an oil circuit. The first pumping valve group 9 and the second pumping valve group 11 are also connected to the pumping hydraulic pump group 13 via an oil circuit.

[0126] The front chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are connected in parallel through an oil circuit. The parallel connecting chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are connected to the connecting chamber valve group 16 and the connecting chamber hydraulic pump 15 through an oil circuit.

[0127] The first pumping hydraulic cylinder 1 drives the pumping piston to reciprocate within the first pumping cylinder 3, thereby drawing in and expelling material. The second pumping hydraulic cylinder 2 drives the pumping piston to reciprocate within the second pumping cylinder 4, thereby drawing in and expelling material.

[0128] The first cylinder feed valve 6 is connected to the first pumping cylinder 3, and it is used to control the opening and closing of the suction channel of the first pumping cylinder 3. The second cylinder feed valve 5 is connected to the second pumping cylinder 4, and it is used to control the opening and closing of the suction channel of the second pumping cylinder 4. The two-position three-way discharge valve 19 is indirectly connected to the first pumping cylinder 3 through the first cylinder feed valve 6, and the two-position three-way discharge valve 19 is indirectly connected to the second pumping cylinder 4 through the second cylinder feed valve 5. The two-position three-way discharge valve 19 can control the opening and closing of the material discharge channels of the first pumping cylinder 3 and the second pumping cylinder 4, and can also open the material discharge channels of the first pumping cylinder 3 and the second pumping cylinder 4 simultaneously.

[0129] Its workflow is as follows:

[0130] Process 1: The first pumping hydraulic cylinder 1 advances to pump, and the second pumping hydraulic cylinder 2 retracts to suck up material.

[0131] The first cylinder feed valve 6 is closed, the second cylinder feed valve 5 is open, and the material discharge channel of the first pumping cylinder 3 is opened.

[0132] The first pumping valve group 9 is open, the first return valve group 10 is closed, the second pumping valve group 11 is closed, the second return valve group 12 is open, the 16 connecting chamber valve group is closed, and the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 are closed.

[0133] The hydraulic oil discharged by the pumping hydraulic pump unit 13 enters the rear chamber of the first pumping hydraulic cylinder 1, and the hydraulic oil discharged by the connecting chamber hydraulic pump 15 enters the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2. The first pumping hydraulic cylinder 1 moves forward, causing the first pumping material cylinder 3 to push the material outward, and the second pumping hydraulic cylinder 2 moves backward and sucks the material inward into the second pumping material cylinder 4.

[0134] Step 2: The first pumping hydraulic cylinder 1 advances and pumps forward, while the second pumping hydraulic cylinder 2 preloads.

[0135] When the second pumping hydraulic cylinder 2 has finished retracting, the second cylinder feed valve 5 is closed.

[0136] When the connecting chamber valve group 16 opens and the second return valve group 12 closes, the second pumping hydraulic cylinder 2 stops, and the first pumping hydraulic cylinder 1 continues to advance. The hydraulic oil in the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, as well as the hydraulic oil discharged from the connecting chamber hydraulic pump 15, can flow back to the oil tank through the connecting chamber valve group 16.

[0137] The second cylinder pre-pressure valve group 182 opens, and the hydraulic oil in the accumulator 17 and the hydraulic oil discharged from the pre-pressure hydraulic pump 14 enter the rear chamber of the second pumping hydraulic cylinder 2, causing the second pumping hydraulic cylinder 2 to move forward and pressurize the material in the second pumping material cylinder 4.

[0138] By setting the control pressure of the pressure control valve 183, the pre-pressure of the pre-pressurized hydraulic oil can be made equal to (or similar to) the pressure of the pumped hydraulic oil in the rear chamber of the first pumping hydraulic cylinder 1, thereby making the pressure of the material in the first pumping cylinder 3 and the second pumping cylinder 4 equal to (or similar to) the pressure of the material.

[0139] Step 3: The first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 work together to pump:

[0140] When the first pumping hydraulic cylinder 1 advances to a distance from the end point, the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 close, and the hydraulic oil discharged by the pre-pressure hydraulic pump 14 enters the accumulator 17.

[0141] When the connecting chamber valve group 16 is opened and the second pumping valve group 11 is opened, the two-position three-way discharge valve 19 starts to switch directions. The pumping hydraulic pump group 13 is simultaneously connected to the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2. The hydraulic oil discharged from it can simultaneously enter the rear chamber 1 of the first pumping hydraulic cylinder and the rear chamber of the second pumping hydraulic cylinder 2.

[0142] Step 4: The first pumping hydraulic cylinder 1 retracts to suck up material, and the second pumping hydraulic cylinder 2 advances to pump material.

[0143] After the material discharge channel of the first pump feeding cylinder 3 is closed

[0144] The second pumping valve group 11 is closed, the second return valve group 12 is open, and the connecting chamber valve group 16 is closed. The hydraulic oil discharged by the pumping hydraulic pump group 13 enters the rear chamber of the second pumping hydraulic cylinder 2, and the hydraulic oil discharged by the connecting chamber hydraulic pump 15 enters the parallel connecting chamber of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2. The second pumping hydraulic cylinder 2 moves forward, causing the second pumping material cylinder 4 to push the material outward, and the second pumping hydraulic cylinder 1 moves backward to suck the material inward into the first pumping material cylinder 3.

[0145] Step 5: The second pumping hydraulic cylinder 2 advances and pumps forward, while the first pumping hydraulic cylinder 1 is preloaded.

[0146] When the first pumping hydraulic cylinder 1 has finished retracting, the first cylinder feed valve 6 is closed.

[0147] When the connecting chamber valve group 16 opens and the first return valve group 10 closes, the first pumping hydraulic cylinder 1 stops, and the second pumping hydraulic cylinder 2 continues to advance. The hydraulic oil in the parallel connecting chambers of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2, as well as the hydraulic oil discharged from the connecting chamber hydraulic pump 15, can flow back to the oil tank via the connecting chamber valve group 16.

[0148] The first cylinder pre-pressure valve group 181 opens, and the hydraulic oil in the accumulator 17 and the hydraulic oil discharged from the pre-pressure hydraulic pump 14 enter the rear chamber of the first pumping hydraulic cylinder 1, causing the first pumping hydraulic cylinder 1 to move forward and pressurize the material in the first pumping material cylinder 3.

[0149] By setting the pressure of the pressure control valve 183, the pre-pressure of the pre-pressurized hydraulic oil can be made equal to (or similar to) the pressure of the pumped hydraulic oil in the rear chamber of the second pumping hydraulic cylinder 2, thereby making the pressure of the material in the first pumping cylinder 3 and the second pumping cylinder 4 equal to (or similar to) the pressure of the material.

[0150] Step 6: The first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 work together to pump:

[0151] When the second pumping hydraulic cylinder 2 advances to a distance from the end point, the first cylinder pre-pressure valve group 181 and the second cylinder pre-pressure valve group 182 close, and the hydraulic oil discharged by the pre-pressure hydraulic pump 14 enters the accumulator 17.

[0152] When the connecting chamber valve group 16 is opened and the first pumping valve group 9 is opened, the two-position three-way discharge valve 19 starts to switch directions. The pumping hydraulic pump group 13 is simultaneously connected to the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2. The hydraulic oil discharged from it can simultaneously enter the rear chamber of the first pumping hydraulic cylinder 1 and the rear chamber of the second pumping hydraulic cylinder 2.

[0153] By repeating the above steps 1 to 6 in a cyclical manner, continuous pressure and flow stabilization pumping of materials can be achieved.

[0154] In the above embodiments, since the displacement of the pressure oil output by the pumping hydraulic pump set 13 is relatively constant, the piston areas of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 are the same, the diameters of the pumping pistons or pumping plungers of the two cylinders are also the same, and all the pressure oil output by the pumping hydraulic pump set 13 enters the rear chamber of the first pumping hydraulic cylinder 1 and / or the second pumping hydraulic cylinder 2.

[0155] Therefore, the flow rate output by a single cylinder pump is the same as the flow rate output by two cylinders pumping simultaneously. Furthermore, during the simultaneous pumping and pumping reversal processes, the forward speeds of the first pumping hydraulic cylinder 1 and the second pumping hydraulic cylinder 2 increase and decrease in opposite directions, thereby ensuring a smooth transition during pumping reversal and maintaining a stable flow rate and pressure of the pumped material.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A pressure-stabilizing and flow-stabilizing pump with pre-pressure function, comprising: Two pumping hydraulic cylinders alternately advance and retreat to perform material suction and pumping / pushing. Its distinguishing feature is that it further includes a pre-compression unit, which is used to drive the pumping hydraulic cylinder forward to pre-compress the sucked-in material after the pumping hydraulic cylinder has finished retracting and before pumping and pushing. The pre-pressure unit includes a pre-pressure valve group (18) and a pre-pressure pressure source. The pre-pressure valve group (18) controls the opening and closing of the pre-pressure oil circuit between the rear chamber of the pumping hydraulic cylinder (1) and the pre-pressure pressure source.

2. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 1, characterized in that, The pressure-stabilizing and flow-stabilizing pump includes: a first pumping hydraulic cylinder (1), a second pumping hydraulic cylinder (2), a first pumping valve group (9), a second pumping valve group (11), a first return valve group (10), a second return valve group (12), a pre-pressure valve group (18), and a pumping hydraulic pump group (13). The rear chamber of the first pumping hydraulic cylinder (1) is connected to both the first pumping valve group (9) and the first return valve group (10) via oil circuits. The first pumping valve group (9) is also connected to the pumping hydraulic pump group (13) via oil circuits, and the first return valve group (10) is connected to the return oil circuit. The first pumping valve group (9) controls the opening and closing of the oil circuit between the rear chamber of the first pumping hydraulic cylinder (1) and the pumping hydraulic pump group (13), and the first return valve group (10) controls the opening and closing of the return oil circuit of the rear chamber of the first pumping hydraulic cylinder (1). The rear chamber of the second pumping hydraulic cylinder (2) is connected to both the second pumping valve group (11) and the second return valve group (12) via oil circuits. The second pumping valve group (11) is also connected to the pumping hydraulic pump group (13) via oil circuits, and the second return valve group (12) is connected to the return oil circuit. The second pumping valve assembly (11) is used to control the opening and closing of the oil circuit between the rear chamber of the second pumping hydraulic cylinder (2) and the pumping hydraulic pump assembly (13). The second return oil valve assembly (12) is used to control the opening and closing of the return oil circuit of the rear chamber of the second pumping hydraulic cylinder (2). The pre-pressure valve assembly (18) is connected to the rear chamber of the first pumping hydraulic cylinder (1) and the rear chamber of the second pumping hydraulic cylinder (2) through an oil circuit, and is used to control the opening and closing of the pre-pressure oil circuit of the first pumping hydraulic cylinder (1) and the pre-pressure oil circuit of the second pumping hydraulic cylinder (2).

3. The pressure-stabilizing and flow-stabilizing pump with pre-compression function according to claim 2, characterized in that, It further includes a connecting chamber valve group (16), in which the front chamber of the first pumping hydraulic cylinder (1) and the front chamber of the second pumping hydraulic cylinder (2) are connected in parallel through an oil circuit. The connecting chamber valve group (16) is connected to the parallel connecting chamber of the first pumping hydraulic cylinder (1) and the second pumping hydraulic cylinder (2) through an oil circuit. The connecting chamber valve group (16) is also connected to the return oil circuit. The connecting chamber valve group (16) controls the opening and closing of the return oil circuit of the front chamber of the first pumping hydraulic cylinder (1) and the front chamber of the second pumping hydraulic cylinder (2).

4. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 2, characterized in that, The pre-pressure valve group (18) further includes a pressure control valve (183), which is connected to the oil circuit of the pre-pressure valve group (18) and is used to control the pressure of the pre-pressure hydraulic oil flowing into the first pumping hydraulic cylinder (1) and the second pumping hydraulic cylinder (2), so that the pressure of the pre-pressure hydraulic oil is equal to or close to the pressure of the pumping hydraulic oil of the first pumping hydraulic cylinder (1) and the second pumping hydraulic cylinder (2).

5. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 3, characterized in that, The pre-pressure valve group (18) further includes a pressure control valve (183), which is connected to the oil circuit of the pre-pressure valve group (18) and is used to control the pressure of the pre-pressure hydraulic oil flowing into the first pumping hydraulic cylinder (1) and the second pumping hydraulic cylinder (2), so that the pressure of the pre-pressure hydraulic oil is equal to or close to the pressure of the pumping hydraulic oil of the first pumping hydraulic cylinder (1) and the second pumping hydraulic cylinder (2).

6. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to any one of claims 2 to 5, characterized in that, The pre-pressure valve group (18) further includes a first cylinder pre-pressure valve group (181) and a second cylinder pre-pressure valve group (182). The first cylinder pre-pressure valve group (181) is connected to the first pumping hydraulic cylinder (1) through an oil circuit and is used to control the on / off of the pre-pressure oil circuit of the first pumping hydraulic cylinder (1). The second cylinder pre-pressure valve group (182) is connected to the second pumping hydraulic cylinder (2) through an oil circuit and is used to control the on / off of the pre-pressure oil circuit supplied to the second pumping hydraulic cylinder (2). When the first pumping hydraulic cylinder (1) or the second pumping hydraulic cylinder (2) is in operation, the pre-pressure valve group (182) can be opened and closed. (2) After the material is sucked up, the first cylinder pre-pressure valve group (181) or the second cylinder pre-pressure valve group (182) is connected to the first pumping hydraulic cylinder (1) or the second pumping hydraulic cylinder (2) waiting to take over the pumping, so that the pre-pressure hydraulic oil can enter the first pumping hydraulic cylinder (1) or the second pumping hydraulic cylinder (2), drive the first pumping hydraulic cylinder (1) or the second pumping hydraulic cylinder (2) to move forward and pre-pressurize the material sucked into the first pumping cylinder (3) or the second pumping cylinder (4) through the pumping piston.

7. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 6, characterized in that, The first cylinder pre-pressure valve group (181) includes a first check valve (1811), and the second cylinder pre-pressure valve group (182) includes a second check valve (1821). The first check valve (1811) is connected to the output oil line of the first cylinder pre-pressure valve group (181) to prevent the hydraulic oil in the first pumping hydraulic cylinder (1) from flowing to the pre-pressure valve group (18). The second check valve (1821) is connected to the output oil line of the second cylinder pre-pressure valve group (182) to prevent the hydraulic oil in the second pumping hydraulic cylinder (2) from flowing to the pre-pressure valve group (18).

8. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to any one of claims 2 to 5, characterized in that, It further includes an accumulator (17) which is connected to the pre-pressure valve group (18) via an oil passage for storing hydraulic oil discharged from the pre-pressure hydraulic pump and providing pre-pressure hydraulic oil to the first pumping hydraulic cylinder (1) and the second pumping hydraulic cylinder (2).

9. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to any one of claims 2 to 5, characterized in that, Further including a second cylinder feed valve (5), a first cylinder feed valve (6), a second cylinder discharge valve (7), and a first cylinder discharge valve (8), the first cylinder feed valve (6) and the first cylinder discharge valve (8) are directly or indirectly connected to the first pumping cylinder (3). The first cylinder feed valve (6) is used to control the opening and closing of the suction channel of the first pumping cylinder (3), and the first cylinder discharge valve (8) is used to control the opening and closing of the discharge channel of the first pumping cylinder (3). The second cylinder feed valve (5) and the second cylinder discharge valve (7) are directly or indirectly connected to the second pumping cylinder (4). The second cylinder feed valve (5) is used to control the opening and closing of the suction channel of the second pumping cylinder (4), and the second cylinder discharge valve (7) is used to control the opening and closing of the discharge channel of the second pumping cylinder (4).

10. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 6, characterized in that, Further including a second cylinder feed valve (5), a first cylinder feed valve (6), a second cylinder discharge valve (7), and a first cylinder discharge valve (8), the first cylinder feed valve (6) and the first cylinder discharge valve (8) are directly or indirectly connected to the first pumping cylinder (3). The first cylinder feed valve (6) is used to control the opening and closing of the suction channel of the first pumping cylinder (3), and the first cylinder discharge valve (8) is used to control the opening and closing of the discharge channel of the first pumping cylinder (3). The second cylinder feed valve (5) and the second cylinder discharge valve (7) are directly or indirectly connected to the second pumping cylinder (4). The second cylinder feed valve (5) is used to control the opening and closing of the suction channel of the second pumping cylinder (4), and the second cylinder discharge valve (7) is used to control the opening and closing of the discharge channel of the second pumping cylinder (4).

11. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 7, characterized in that, Further including a second cylinder feed valve (5), a first cylinder feed valve (6), a second cylinder discharge valve (7), and a first cylinder discharge valve (8), the first cylinder feed valve (6) and the first cylinder discharge valve (8) are directly or indirectly connected to the first pumping cylinder (3). The first cylinder feed valve (6) is used to control the opening and closing of the suction channel of the first pumping cylinder (3), and the first cylinder discharge valve (8) is used to control the opening and closing of the discharge channel of the first pumping cylinder (3). The second cylinder feed valve (5) and the second cylinder discharge valve (7) are directly or indirectly connected to the second pumping cylinder (4). The second cylinder feed valve (5) is used to control the opening and closing of the suction channel of the second pumping cylinder (4), and the second cylinder discharge valve (7) is used to control the opening and closing of the discharge channel of the second pumping cylinder (4).

12. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to any one of claims 2 to 5, characterized in that, Further includes a second cylinder feed valve (5), a first cylinder feed valve (6) and a two-position three-way discharge valve (19). The first pumping cylinder (3) is connected to the first cylinder feed valve (6) to control the opening and closing of the material intake channel of the first pumping cylinder (3). The second pump feeding cylinder (4) is connected to the second cylinder feed valve (5) and is used to control the opening and closing of the material suction channel of the second pump feeding cylinder (4); The two-position three-way discharge valve (19) is directly or indirectly connected to the first pumping cylinder (3) and the second pumping cylinder (4) to control the opening and closing of the material discharge channels of the first pumping cylinder (3) and the second pumping cylinder (4). It can also open or partially open the material discharge channels of the first pumping cylinder (3) and the second pumping cylinder (4) at the same time.

13. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 6, characterized in that, Further includes a second cylinder feed valve (5), a first cylinder feed valve (6) and a two-position three-way discharge valve (19). The first pumping cylinder (3) is connected to the first cylinder feed valve (6) to control the opening and closing of the material intake channel of the first pumping cylinder (3). The second pump feeding cylinder (4) is connected to the second cylinder feed valve (5) and is used to control the opening and closing of the material suction channel of the second pump feeding cylinder (4); The two-position three-way discharge valve (19) is directly or indirectly connected to the first pumping cylinder (3) and the second pumping cylinder (4) to control the opening and closing of the material discharge channels of the first pumping cylinder (3) and the second pumping cylinder (4). It can also open or partially open the material discharge channels of the first pumping cylinder (3) and the second pumping cylinder (4) at the same time.

14. The pressure-stabilizing and flow-stabilizing pump with pre-pressure function according to claim 7, characterized in that, Further includes a second cylinder feed valve (5), a first cylinder feed valve (6) and a two-position three-way discharge valve (19). The first pumping cylinder (3) is connected to the first cylinder feed valve (6) to control the opening and closing of the material intake channel of the first pumping cylinder (3). The second pump feeding cylinder (4) is connected to the second cylinder feed valve (5) and is used to control the opening and closing of the material suction channel of the second pump feeding cylinder (4); The two-position three-way discharge valve (19) is directly or indirectly connected to the first pumping cylinder (3) and the second pumping cylinder (4) to control the opening and closing of the material discharge channels of the first pumping cylinder (3) and the second pumping cylinder (4). It can also open or partially open the material discharge channels of the first pumping cylinder (3) and the second pumping cylinder (4) at the same time.

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