Two-cylinder hydraulic continuous delivery pump

Abstract

The invention discloses a two-cylinder hydraulic continuous conveying pump which comprises at least two conveying modules, each conveying module comprises a hydraulic cylinder and a conveying cylinder, a piston or a plunger is arranged in each conveying cylinder, and the hydraulic cylinders are used for driving the pistons or the plungers in the conveying cylinders to reciprocate; a rodless cavity of the conveying cylinder is communicated to a slurry inlet pipe through a slurry inlet valve, the rodless cavity of the conveying cylinder is further communicated to a slurry discharging pipe through a slurry discharging valve, the slurry inlet valve and the slurry discharging valve are controlled in an interlocking mode and are independently controlled, and when the slurry inlet valve or the slurry discharging valve is completely closed in place, the slurry discharging valve or the slurry inlet valve starts to be opened, and it is ensured that the slurry discharging valve or the slurry inlet valve is opened at any time. A rodless cavity of the conveying cylinder cannot be communicated with the slurry inlet pipe and the slurry discharge pipe at the same time; the two hydraulic cylinders in the two sets of conveying modules are independently controlled respectively, the duration of the slurry feeding process is smaller than that of the slurry discharging process, and according to the scheme, the slurry can be conveyed in a relay mode without speed reduction and pause when the cylinders of the pump are reversed.

Description

Technical Field

[0001] The present invention relates to the field of positive displacement pumps, and in particular to a two-cylinder hydraulic continuous delivery pump. Background Art

[0002] A positive displacement pump is a pump that relies on the reciprocating motion of the working element in the pump cylinder to alternately increase and decrease the working volume to achieve the suction and discharge of liquid. When the working volume increases, low pressure is formed in the pump body and the liquid is sucked in; when the working volume decreases, the liquid in the pump body is squeezed out and discharged at a higher pressure.

[0003] Similar to concrete pumps, filling pumps, ceramic plunger pumps, etc., since the application scenarios require very high pressure, hydraulic pressure is often used as the power source. At the same time, in order to improve the conveying efficiency, two hydraulic cylinders in series are often used to work alternately, such as Figure 1 As shown, it includes a first hydraulic cylinder, a first conveying cylinder, a second hydraulic cylinder, and a second conveying cylinder. The first hydraulic cylinder drives the piston in the first conveying cylinder to perform reciprocating motion, and the second hydraulic cylinder drives the piston in the second conveying cylinder to perform reciprocating motion. The rod chambers of the first hydraulic cylinder and the second hydraulic cylinder are connected together through a pipeline; the rodless chamber of the first conveying cylinder and the rodless chamber of the second conveying cylinder are also alternately connected to the slurry inlet pipe or the slurry discharge pipe under the control of the slurry inlet valve and the slurry discharge valve, and at any time during the action of the hydraulic cylinder, only one of the first conveying cylinder and the second conveying cylinder is connected to the slurry inlet pipe, and the other is connected to the slurry discharge pipe.

[0004] More specifically: Figure 1 As shown, the rodless chambers of the first conveying cylinder and the second conveying cylinder are connected to the slurry inlet pipe via the slurry inlet valve, and are connected to the slurry discharge pipe via the slurry discharge valve. The slurry inlet valve and the slurry discharge valve are linked to each other. When the slurry inlet valve and the slurry discharge valve are in full motion, the same conveying cylinder can only be connected to one of the slurry inlet pipe or the slurry discharge pipe, and cannot be connected to both the slurry inlet pipe and the slurry discharge pipe at the same time. When the slurry inlet valve and the slurry discharge valve are in full motion, one and only one conveying cylinder is connected to the slurry inlet pipe, and one and only one conveying cylinder is connected to the slurry discharge pipe.

[0005] The characteristics of the above-mentioned pump are small number of cylinders, simple structure and easy control. The disadvantage is that since the two hydraulic cylinders are connected in series, both will inevitably move at the same time, so during the reversing period, it is necessary to wait for the slurry inlet valve and the slurry discharge valve to move in place. During the waiting process, the hydraulic cylinder cannot move, that is, the material transportation is in a suspended state. On the one hand, this leads to a decrease in the material transportation efficiency. On the other hand, the sudden stop of the material will also cause an impact on the pipeline, causing vibration of the equipment and pipeline, and the transported slurry is also prone to precipitation in the pipeline.

[0006] Therefore, it is necessary to develop a two-cylinder hydraulic continuous delivery pump. Summary of the invention

[0007] The technical problem to be solved by the present invention is how to overcome the problem that the existing hydraulic delivery pump needs to stop delivering materials during the reversing period.

[0008] The specific technical solution of the present invention to solve the above technical problems is:

[0009] A two-cylinder hydraulic continuous delivery pump, comprising at least two sets of delivery modules, wherein the two sets of delivery modules respectively comprise a hydraulic cylinder and a delivery cylinder, wherein a piston or a plunger is arranged in the delivery cylinder, and the hydraulic cylinder is used to drive the piston or the plunger in the delivery cylinder to perform reciprocating motion;

[0010] The rodless chamber of the conveying cylinder is connected to the slurry inlet pipe through the slurry inlet valve, and the rodless chamber of the conveying cylinder is also connected to the slurry discharge pipe through the slurry discharge valve. The slurry inlet valve and the slurry discharge valve are interlocked and controlled, and the slurry inlet valve and the slurry discharge valve are independently controlled. When the slurry inlet valve or the slurry discharge valve is completely closed, the slurry discharge valve or the slurry inlet valve starts to open, ensuring that at any time, the rodless chamber of the conveying cylinder will not be connected to the slurry inlet pipe and the slurry discharge pipe at the same time; the two hydraulic cylinders in the two sets of conveying modules are independently controlled, and the slurry inlet process duration is shorter than the slurry discharge process duration.

[0011] Compared with the prior art, this solution has the following beneficial effects:

[0012] Since the duration of the slurry feeding process is shorter than that of the slurry discharging process, when the first group of conveying modules is still in the slurry discharging process, the second group of conveying modules has completed the slurry feeding process, and the slurry feeding valve of the second group of conveying modules is closed, and the slurry discharging valve of the second group of conveying modules is opened. When the first group of conveying modules gradually finishes discharging slurry, the second group of conveying modules gradually starts to take over the slurry discharging process.

[0013] During the slurry discharge process of the second group of conveying modules, the slurry discharge valve of the first group of conveying modules is closed, and the slurry inlet valve of the first group of conveying modules is opened. The first group of conveying modules starts to feed slurry, and completes the slurry feeding operation before the slurry discharge of the second group of conveying modules is completed, and the slurry inlet valve of the first group of conveying modules is closed, and the slurry discharge valve of the first group of conveying modules is opened, waiting for the second group of conveying modules to complete slurry discharge before relaying slurry discharge;

[0014] By analogy, the two groups of conveying modules act alternately, so that the slurry in the slurry discharge pipe can be continuously conveyed without pause, avoiding the vibration of the pipeline and equipment caused by the intermittent conveying of materials in the slurry discharge pipe, avoiding the deposition of slurry in the pipeline during the stop period, and improving the conveying efficiency of the slurry.

[0015] Furthermore, a vent pipe connected to the atmosphere is provided at one end of the rod chamber of the delivery cylinder close to the oil cylinder.

[0016] Furthermore, a piston is provided in the delivery cylinder and a piston is provided in the oil cylinder, which has the advantage that the piston is lighter than the plunger;

[0017] Furthermore, the hydraulic cylinder is connected to the slurry discharge hydraulic pump and the slurry feed hydraulic pump via a hydraulic control valve, and the hydraulic cylinder switches between three states: connected to the slurry discharge hydraulic pump, not connected to any hydraulic pump, and connected to the slurry feed hydraulic pump; the slurry discharge hydraulic pump drives the piston in the hydraulic cylinder to move toward the conveying cylinder to achieve the slurry discharge action, and the slurry feed hydraulic pump drives the piston in the hydraulic cylinder to move away from the conveying cylinder to achieve the slurry feed action; the amount of hydraulic oil output per unit time by the slurry discharge hydraulic pump is less than the amount of hydraulic oil output per unit time by the slurry feed hydraulic pump;

[0018] Furthermore, the slurry discharge valve and the slurry inlet valve are respectively provided with valve switch in place sensors for detecting whether the valve is in place;

[0019] Furthermore, the hydraulic cylinder or the delivery cylinder is also provided with a slurry inlet critical detection module and a slurry discharge critical detection module;

[0020] When slurry is fed, the slurry feeding critical detection module is triggered, the slurry feeding hydraulic pump is disconnected, the slurry feeding valve is closed, the slurry discharge valve is opened, and after receiving the slurry discharge valve opening signal and the signal from the slurry discharge critical detection module, the slurry discharge hydraulic pump is connected;

[0021] When discharging slurry, the slurry discharge critical detection module is triggered, the slurry discharge hydraulic pump is disconnected, the slurry discharge valve is closed, and the slurry inlet valve is opened. After receiving the slurry inlet valve opening signal, the slurry inlet hydraulic pump is connected to discharge slurry.

[0022] Furthermore, the conveying module is also provided with a slurry entry limit detection module and a slurry discharge limit detection module, which are used to sense whether the hydraulic cylinder has reached the slurry entry limit point and the slurry discharge limit point, which are the over-limit positions allowed to be reached by the piston during operation. Receiving a signal means that the piston of the hydraulic cylinder may hit the cylinder, and the position of the slurry entry critical detection module or the slurry discharge critical detection module needs to be adjusted to make the hydraulic cylinder move earlier until no signal is received to ensure the safety of the system.

[0023] The slurry feeding limit detection module, the slurry discharging limit detection module, the slurry feeding critical detection module, and the slurry discharging critical detection module can be a limit switch, a proximity switch, a linear sensor, a photoelectric switch, etc. In addition to measuring the position of the piston or plunger in the hydraulic cylinder, the linear sensor can also measure the speed of the piston or plunger.

[0024] Furthermore, the signals of the valve switch in place sensor, the slurry inlet critical detection module and the slurry discharge critical detection module are communicated with the hydraulic control valve. After the control system receives the signal from the valve closing position sensor, the hydraulic control valve will act to control the next action of the hydraulic cylinder.

[0025] When the first set of conveying modules is feeding slurry, the slurry feeding critical detection module is triggered, and the connection between the hydraulic cylinder of the first set of conveying modules and the slurry feeding hydraulic pump is disconnected, the slurry feeding valve of the first set of conveying modules is closed, and the slurry discharge valve of the first set of conveying modules is opened. After receiving the slurry discharge valve opening signal of the first set of conveying modules and the signal that the slurry discharge critical detection module of the second set of conveying modules is triggered, the system controls the hydraulic cylinder connected to the first set of conveying modules to be connected to the slurry discharge hydraulic pump to start slurry discharge;

[0026] When the second conveying module is discharging slurry, after the system receives the signal that the slurry discharge critical detection module of the second conveying module is triggered, it opens the connection between the hydraulic cylinder of the first conveying module and the slurry discharge hydraulic pump, disconnects the connection between the hydraulic cylinder of the second conveying module and the slurry discharge hydraulic pump, closes the slurry discharge valve of the second conveying module, and after receiving the signal that the slurry discharge valve of the second conveying module is closed in place, opens the slurry inlet valve of the second conveying module, and after receiving the signal that the slurry inlet valve of the second conveying module is opened, the system controls the hydraulic cylinder of the second conveying module to connect to the slurry inlet hydraulic pump to start slurry discharge;

[0027] Furthermore, the slurry inlet valve and slurry discharge valve of the first set of conveying modules and the slurry inlet valve and slurry discharge valve of the second set of conveying modules are independently controlled, that is, there are four independent control mechanisms to control the slurry inlet valve and slurry discharge valve in the two sets of conveying modules respectively, or the slurry inlet valve and slurry discharge valve are mechanical one-way valves, which are automatically opened and closed by the pressure difference on both sides of the valve core. Therefore, if the slurry inlet valve and slurry discharge valve are mechanical one-way valves, there is no need to wait for the signal that the slurry inlet valve and slurry discharge valve are in place during the whole process.

[0028] Furthermore, the slurry inlet valve and the slurry discharge valve are both a type of conical valve, a flat valve, or a ball valve.

[0029] Furthermore, the slurry inlet valve and the slurry discharge valve are driven by one of a motor drive, an electromagnetic drive, a hydraulic drive, and a pneumatic drive.

[0030] Furthermore, when the slurry feed limit module or the slurry discharge limit module of the conveying module receives a signal, it means that the running distance after the hydraulic cylinder is closed is too long, and the piston may hit the hydraulic cylinder. Therefore, it is necessary to adjust the position of the slurry feed critical detection module or the slurry discharge critical detection module, and start executing the "cut-off hydraulic cylinder action" instruction earlier to ensure that the slurry feed limit module or the slurry discharge limit module will not be triggered during normal process, thereby ensuring system safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of an existing two-cylinder driven hydraulic piston pump;

[0032] Figure 2 This is a schematic diagram of the initial state of the two-cylinder hydraulic continuous delivery pump before starting the first embodiment [piston + piston];

[0033] Figure 3This is a schematic diagram of the first conveying module on standby and the second conveying module independently discharging slurry in the first embodiment;

[0034] Figure 4 This is a schematic diagram of the state in which the first conveying module and the second conveying module discharge slurry at the same time in Example 1;

[0035] Figure 5 This is a schematic diagram of the state in which the first conveying module independently discharges slurry and the second conveying module is closed for slurry discharge in Example 1;

[0036] Figure 6 This is a schematic diagram of the first conveying module independently discharging slurry and the second conveying module feeding slurry in Example 1;

[0037] Figure 7 Schematic diagram of a two-cylinder continuously driven hydraulic piston pump in Example 2 [Linear sensor];

[0038] Figure 8 Schematic diagram of the two-cylinder continuous drive hydraulic piston pump in Example 3 [one-way valve];

[0039] In the accompanying drawings, the component names represented by the reference numerals are listed as follows:

[0040] 10. First hydraulic cylinder; 11. First delivery cylinder; 12. First slurry inlet valve; 13. First slurry discharge valve; 14. First bracket; 15. First upper oil pipe; 16. First piston; 171. First slurry discharge limit switch; 172. First slurry discharge critical switch; 173. First slurry inlet critical switch; 174. First slurry inlet limit switch; 18. First piston rod; 19. First lower oil pipe;

[0041] 20. Second hydraulic cylinder; 21. Second delivery cylinder; 22. Second slurry inlet valve; 23. Second slurry discharge valve; 24. Second bracket; 25. Second upper oil pipe; 26. Second piston; 271. Second slurry discharge limit switch; 272. Second slurry discharge critical switch; 273. Second slurry inlet critical switch; 274. Second slurry inlet limit switch; 28. Second piston rod; 29. ​​Second lower oil pipe;

[0042] 30. Connecting oil pipe; 31. Slurry inlet pipe; 32. Slurry discharge pipe; 33. First linear sensor; 34. Second linear sensor. DETAILED DESCRIPTION

[0043] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. In the description of the embodiments of the present invention, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate an orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the invented product is usually placed when used, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, "first", "second", "third", etc. in the names of the technical features are only used to distinguish the description, and cannot be understood as indicating or implying relative importance, nor do they include an order relationship.

[0044] like Figure 1 As shown, it is a delivery cylinder in the prior art, the first hydraulic cylinder 10 and the second hydraulic cylinder 20 both have pistons, the rodless chamber of the hydraulic cylinder is connected to the upper oil pipe, the rod chamber of the hydraulic cylinder is connected to the lower oil pipe, the lower oil pipes of the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are connected together through the connecting oil pipe 30, that is, the rod chambers of the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are connected together;

[0045] The rodless chambers of the first conveying cylinder 11 and the second conveying cylinder 21 are connected to the slurry inlet pipe 31 through the slurry inlet valve, and are connected to the slurry discharge pipe 32 through the slurry discharge valve. The slurry inlet valve and the slurry discharge valve are linked to each other. When the slurry inlet valve and the slurry discharge valve are in full motion, the same conveying cylinder can only be connected to one of the slurry inlet pipe 31 or the slurry discharge pipe 32, and cannot be connected to both the slurry inlet pipe 31 and the slurry discharge pipe 32 at the same time. When the slurry inlet valve and the slurry discharge valve are in full motion, one and only one conveying cylinder is connected to the slurry inlet pipe 31, and one and only one conveying cylinder is connected to the slurry discharge pipe 32.

[0046] The two driving hydraulic cylinders are connected in series. Due to the incompressibility of the hydraulic oil, the two will inevitably move at the same time. For example, when the piston in the first hydraulic cylinder 10 moves upward, the space of the rod chamber of the first hydraulic cylinder 10 increases, and the hydraulic oil in the rod chamber will be transferred from the rod chamber of the second hydraulic cylinder 20 to the rod chamber of the first hydraulic cylinder 10, thereby driving the second hydraulic cylinder 20 to move downward, and vice versa. This structure is relatively simple to control, but during the reversing of the hydraulic cylinder, it is necessary to wait for the slurry inlet valve and the slurry discharge valve to be fully actuated before starting the next action of the hydraulic cylinder. During this waiting process, the hydraulic cylinder cannot move, and the material transportation is suspended. On the one hand, this leads to a reduction in the material transportation efficiency. On the other hand, the sudden stop of the material will also cause an impact on the pipeline, causing vibration of the equipment and pipeline, and the transported slurry is also prone to precipitation in the pipeline.

[0047] like Figure 2Shown is an embodiment of the hydraulic continuous delivery pump of the present invention:

[0048] A two-cylinder hydraulic continuous delivery pump comprises two sets of delivery modules of the same size, wherein the two sets of delivery modules respectively comprise a hydraulic cylinder and a delivery cylinder, that is, the first set of delivery modules comprises a first hydraulic cylinder 10, a first bracket 14, and a first delivery cylinder 11, and the second set of delivery modules comprises a second hydraulic cylinder 20, a second bracket 24, and a second delivery cylinder 21, wherein pistons are arranged in the hydraulic cylinder and the delivery cylinder, and specifically, a first piston 16 is arranged in the first delivery cylinder 11, and a second piston 26 is arranged in the second delivery cylinder 21, the first piston 16 is connected to the piston in the first hydraulic cylinder 10 via a first piston rod 18, and the second piston 26 is connected to the piston in the second hydraulic cylinder 20 via a second piston rod 28, and the hydraulic cylinder is used to drive the piston in the delivery cylinder to reciprocate; a vent pipe connected to the atmosphere is arranged in the rod cavity of the delivery cylinder near one end of the oil cylinder.

[0049] The rodless chamber of the first hydraulic cylinder 10 is connected to the first upper oil pipe 15, and the rod chamber is connected to the first lower oil pipe 19; the rodless chamber of the second hydraulic cylinder 20 is connected to the second upper oil pipe 25, and the rod chamber is connected to the second lower oil pipe 29;

[0050] The rodless chamber of the first conveying cylinder 11 is connected to the slurry inlet pipe 31 through the first slurry inlet valve 12, and the rodless chamber of the first conveying cylinder 11 is also connected to the slurry discharge pipe 32 through the first slurry discharge valve 13, the rodless chamber of the second conveying cylinder 21 is connected to the slurry inlet pipe 31 through the second slurry inlet valve 22, and the rodless chamber of the second conveying cylinder 21 is also connected to the slurry discharge pipe 32 through the second slurry discharge valve 23;

[0051] The first slurry inlet valve 12 is interlocked with the first slurry discharge valve 13, the second slurry inlet valve 22 is interlocked with the second slurry discharge valve 23, and the first slurry inlet valve 12, the second slurry inlet valve 22 and the first slurry discharge valve 13, the second slurry discharge valve 23 are independently controlled, and when the slurry inlet valve or the slurry discharge valve is completely closed, the slurry discharge valve or the slurry inlet valve starts to open, ensuring that at any time, the rodless cavity of the conveying cylinder will not be connected to the slurry inlet pipe 31 and the slurry discharge pipe 32 at the same time, because the rodless cavity is connected to the slurry inlet pipe 31 and the slurry discharge pipe 32 at the same time, which means that the slurry inlet pipe 31 and the slurry discharge pipe 32 are connected together, and during normal operation, the pressure of the slurry discharge pipe 32 is greater than the pressure of the slurry inlet pipe 31, and the connection between the two necessarily means that the slurry discharge pipe 32 is connected. The material in the slurry pipe 32 will be pushed back into the slurry inlet pipe 31, which is an undesirable result; the two hydraulic cylinders in the two conveying modules are independently controlled, and the duration of the slurry feeding process is shorter than the duration of the slurry discharging process. This is a very core link, so that the seamless connection of the slurry discharging actions of the two conveying modules can be achieved. During the discharging process of the first conveying cylinder 11, the second conveying cylinder 21 completes the slurry feeding action in a time shorter than the discharging time, and waits for the first conveying cylinder 11 to complete the discharging. Once the first conveying cylinder 11 completes the discharging, the second conveying cylinder 21 seamlessly follows up the discharging immediately. At the same time, the first conveying cylinder 11 switches to slurry feeding, and the cycle is repeated in sequence to achieve continuous material transportation.

[0052] Furthermore, the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are connected to the slurry discharge hydraulic pump and the slurry feed hydraulic pump through the control of the hydraulic control valve. The first hydraulic cylinder 10 and the second hydraulic cylinder 20 are switched between the three states of being connected to the slurry discharge hydraulic pump, not being connected to any hydraulic pump, and being connected to the slurry feed hydraulic pump; the slurry discharge hydraulic pump drives the piston in the hydraulic cylinder to move toward the conveying cylinder to achieve the slurry discharge action, and the slurry feed hydraulic pump drives the piston in the hydraulic cylinder to move away from the conveying cylinder to achieve the slurry feed action; the amount of hydraulic oil output per unit time by the slurry discharge hydraulic pump is less than the amount of hydraulic oil output per unit time by the slurry feed hydraulic pump. When the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are equal in size, the effect of the slurry feed time being less than the slurry discharge time can be achieved. Or the amount of hydraulic oil output per unit time by the slurry discharge hydraulic pump is equal to the amount of hydraulic oil output per unit time by the slurry feed hydraulic pump. When the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are equal in size, due to the small effective area of ​​the hydraulic oil in the dry cavity (the hydraulic rod occupies part of the effective area), under the same amount of oil, the running speed will be faster, and the effect of the slurry feed time being less than the slurry discharge time can be achieved.

[0053] Furthermore, the slurry discharge valve and the slurry inlet valve are respectively provided with valve switch position sensors for detecting whether the valves are opened and closed. The first slurry discharge valve 13 and / or the second slurry discharge valve 23 will not be opened until the first slurry discharge valve 12 and the second slurry discharge valve 22 are completely closed. The first slurry inlet valve 12 and / or the second slurry inlet valve 22 will not be opened until the first slurry discharge valve 13 and the second slurry discharge valve 23 are completely closed, so as to ensure that the slurry inlet pipe 31 and the slurry discharge pipe 32 will not be connected at any time.

[0054] Furthermore, a slurry entry limit detection module, a slurry discharge limit detection module, a slurry entry critical detection module and a slurry discharge critical detection module are provided. The slurry entry critical detection module is located on the side of the slurry entry limit detection module close to the slurry discharge limit detection module, and the slurry discharge critical detection module is located on the side of the slurry discharge limit detection module close to the slurry entry limit detection module. When the slurry entry critical detection module and the slurry discharge critical detection module are triggered, the power source of the hydraulic cylinder will be cut off, and the brake valve of the hydraulic cylinder will be switched.

[0055] The slurry feed limit detection module and the slurry discharge limit detection module are used to sense whether the hydraulic cylinder has reached the slurry feed limit point and the slurry discharge limit point. The slurry feed limit point and the slurry discharge limit point are the limit positions allowed to be reached during the operation of the piston. The slurry feed limit point corresponds to the position where the slurry feed is completed, and the slurry discharge limit point corresponds to the position where the slurry discharge is completed. Under normal circumstances, triggering is not allowed. Once triggered, it means that the hydraulic cylinder is at risk of colliding with the cylinder. Therefore, if the slurry feed limit detection module or the slurry discharge limit detection module is triggered in daily work, it means that the time to cut off the power source of the hydraulic cylinder is too late. It is necessary to adjust the position of the slurry feed critical detection module or the slurry discharge critical detection module to ensure that the slurry feed limit detection module or the slurry discharge limit detection module will not be triggered.

[0056] In this example, the above-mentioned position detection is specifically achieved by using limit switches, that is, the first hydraulic cylinder 10 is provided with a first slurry feed limit switch 174, a first slurry discharge limit switch 171, a first slurry feed critical switch 173 and a first slurry discharge critical switch 172, and the second hydraulic cylinder 20 is provided with a second slurry feed limit switch 274, a second slurry discharge limit switch 271, a second slurry feed critical switch 273 and a second slurry discharge critical switch 272.

[0057] When the slurry feeding critical switch is triggered, it means that the slurry feeding is completed, the hydraulic control valve is actuated, the connection between the hydraulic cylinder that executes the slurry feeding and the slurry feeding hydraulic pump is closed, the slurry feeding hydraulic cylinder stops moving, the corresponding slurry feeding valve is closed, and the corresponding slurry discharge valve is opened, waiting for the hydraulic cylinder that is discharging slurry to trigger its corresponding slurry discharge critical switch. After the slurry discharge critical switch is triggered, it means that the slurry discharge is about to end. At this time, the slurry discharge hydraulic pump maintains the hydraulic oil delivery rate unchanged. First, the hydraulic cylinder on the slurry discharge side that has completed the slurry feeding action and is waiting for the slurry discharge is connected to the slurry discharge hydraulic pump, that is, the hydraulic control valve controls the two hydraulic cylinders to connect the slurry discharge hydraulic pump at the same time, and the two hydraulic cylinders jointly take over the hydraulic oil that was originally fully supplied to one hydraulic cylinder by the slurry discharge hydraulic pump, and then disconnect the connection between the hydraulic cylinder on the side that triggers the slurry discharge critical switch and the slurry discharge hydraulic pump, and finally close the slurry discharge valve corresponding to the side that triggers the slurry discharge critical switch. As a result, the first hydraulic cylinder 10 and the second hydraulic cylinder 20 achieve seamless and smooth handover, and the slurry discharge action is switched between the two sets of conveying modules. The slurry discharge action is seamlessly switched. Since the sizes of the hydraulic cylinders and the conveying cylinders of the two sets of conveying modules are the same, and the rate at which the hydraulic oil is delivered by the slurry discharge hydraulic pump remains unchanged, during the switching of the conveying cylinders, the material in the slurry discharge pipe 32 always maintains a constant conveying speed, and there will be no sudden speed increases or decreases, thereby reducing the impact on the pipeline. To ensure safety, once the slurry inlet limit switch and the slurry discharge limit switch are triggered, the connection between the corresponding hydraulic cylinder and the hydraulic pump will be cut off immediately, and the action of the hydraulic cylinder will be stopped.

[0058] The slurry entry critical detection module and the slurry discharge critical detection module can also be proximity switches, linear sensors, photoelectric switches, etc., and their installation positions are not limited to the hydraulic cylinder. For example, they can also be set on the conveying cylinder, etc., as long as they can sense the current position of the piston in the hydraulic cylinder.

[0059] The above actions are realized under the premise that the slurry inlet valve and slurry discharge valve of the first set of conveying modules and the slurry inlet valve and slurry discharge valve of the second set of conveying modules are independently controlled, that is, four independent control mechanisms control the slurry inlet valve and slurry discharge valve in the two sets of conveying modules respectively, and the slurry inlet valve and slurry discharge valve can be a cone valve, a flat valve, or a ball valve. The control of the slurry inlet valve and the slurry discharge valve can be driven by one of motor drive, electromagnetic drive, hydraulic drive, and pneumatic drive.

[0060] The action of the hydraulic control valve can generally be completed within a few milliseconds to tens of milliseconds, but the opening and closing of the slurry inlet valve and the slurry discharge valve require several seconds to more than ten seconds. The switching must meet this time requirement to avoid the slurry inlet pipe and the slurry discharge pipe being connected.

[0061] The following is an example of the use of the aforementioned two-cylinder continuous drive hydraulic piston pump:

[0062] like Figure 3As shown, the first conveying module on the left is currently in the pulp feeding operation, and the second conveying module on the right is currently in the pulp discharging operation. The pulp feeding speed is faster than the pulp discharging speed, so the first pulp feeding critical switch 173 is triggered first and sends a signal, the hydraulic control valve is actuated, the connection between the first hydraulic cylinder 10 and the pulp feeding hydraulic pump is closed, the pulp feeding action is stopped, the first pulp feeding valve 12 is closed, the connection between the first conveying cylinder 11 and the pulp feeding pipe 31 is cut off, and then the first pulp discharging valve 13 is opened. After the second pulp discharging critical switch 272 of the second conveying module is triggered, the hydraulic control valve is actuated to make the first hydraulic cylinder 10 10 is connected to the slurry discharge hydraulic pump, and the first conveying module starts to perform the slurry discharge action, and then the second hydraulic cylinder 20 is cut off from the slurry discharge hydraulic pump. Since the connection between the first hydraulic cylinder 10 and the slurry discharge hydraulic pump is opened first, and then the connection between the second hydraulic cylinder 20 and the slurry discharge hydraulic pump is closed, the two conveying modules are performing slurry discharge during this period, but the total oil inlet flow rate depends on the operation of the slurry discharge hydraulic pump, so it is equal to the oil inlet flow rate when the single conveying module is discharging slurry, which ensures the stability of the material transportation speed in the slurry discharge pipe 32; then the second slurry discharge valve 23 of the second conveying module is gradually closed. After the second slurry discharge valve 23 of the second conveying module is completely closed, the second slurry inlet valve 22 is immediately opened, and the second hydraulic cylinder 20 is connected to the slurry inlet hydraulic pump, so that the second conveying module starts to perform the slurry inlet action, and the above actions are repeated to achieve continuous and uninterrupted transportation of materials.

[0063] A more complete usage is as follows:

[0064] Method steps:

[0065] S1, initial state setting, close all slurry discharge valves, open all slurry inlet valves, the hydraulic cylinder of the second conveying module and the hydraulic cylinder of the first conveying module retreat simultaneously or separately to realize the slurry inlet of the conveying cylinder, such as Figure 2 As shown; after it is detected that the slurry feeding of the conveying cylinder is completed, for example, the slurry feeding critical switch and / or the slurry feeding limit switch is triggered, the driving of all hydraulic cylinders is stopped;

[0066] S2, close all the slurry inlet valves, then open the slurry discharge valve of the second conveying module, and after the slurry discharge valve of the second conveying module is fully opened, control the hydraulic cylinder of the second conveying module to connect to the slurry discharge hydraulic pump to discharge the material in the conveying cylinder of the second conveying module into the slurry discharge pipe 32; Figure 3 As shown;

[0067] S3, without waiting for the second conveying module to finish discharging slurry, open the slurry discharge valve of the first conveying module. Here, as long as the first slurry inlet valve 12 in the first conveying module is completely closed, the first slurry discharge valve 13 of the first conveying module can be opened to connect the first conveying cylinder 11 of the first conveying module with the slurry discharge pipe 32. Figure 4As shown, after receiving the signal that the second pulp discharge critical switch 272 of the second conveying module is triggered, it means that the second conveying module is about to complete the pulp discharge action, and the first hydraulic cylinder 10 of the first conveying module is controlled to connect to the pulp discharge hydraulic pump, and then the connection between the second hydraulic cylinder 20 of the second conveying module and the pulp discharge hydraulic pump is cut off, and the material in the conveying cylinder of the first conveying module is continuously discharged into the pulp discharge pipe 32; then the second pulp discharge valve 23 of the second conveying module is closed, as shown in FIG. Figure 5 As shown;

[0068] S4, after the second slurry discharge valve 23 of the second conveying module is closed, the second slurry inlet valve 22 of the second conveying module is opened, and the second hydraulic cylinder 20 of the second conveying module is controlled to be connected to the slurry inlet hydraulic pump to realize the rapid slurry inlet of the second conveying module, such as Figure 6 As shown; after the second slurry feeding critical switch 273 of the second conveying module is triggered, the communication between the second hydraulic cylinder 20 and the slurry feeding hydraulic pump is cut off, and the second slurry feeding valve 22 of the second conveying module is closed to stop the slurry feeding; based on the difference in oil delivery volume between the slurry feeding hydraulic pump and the slurry discharge hydraulic pump under the same pressure, the slurry discharge of the first conveying module is not completed at this time;

[0069] S5. Open the second slurry discharge valve 23 of the second conveying module without waiting for the first conveying module to complete slurry discharge. Here, as long as the second slurry inlet valve 22 in the second conveying module is completely closed, the second slurry discharge valve 23 of the second conveying module can be opened to connect the second conveying cylinder 21 of the second conveying module with the slurry discharge pipe 32. After receiving the signal that the first slurry discharge critical switch 172 of the first conveying module is triggered, it means that the first conveying module is about to complete the slurry discharge action, and control the second hydraulic cylinder 20 of the second conveying module to connect with the slurry discharge hydraulic pump to discharge the material in the conveying cylinder of the second conveying module into the slurry discharge pipe 32, and then cut off the connection between the first hydraulic cylinder 10 of the first conveying module and the slurry discharge hydraulic pump; then close the first slurry discharge valve 13 of the first conveying module;

[0070] S6, after the first slurry discharge valve 13 of the first conveying module is closed in place, the first slurry inlet valve 12 of the first conveying module is opened, and the first hydraulic cylinder 10 of the first conveying module is controlled to be connected to the slurry inlet hydraulic pump, so as to realize the rapid slurry inlet of the first conveying module; after the first slurry inlet critical switch 173 of the first conveying module is triggered, the connection between the first hydraulic cylinder 10 and the slurry inlet hydraulic pump is cut off, and the first slurry inlet valve 12 of the first conveying module is closed to stop the slurry inlet; based on the difference in oil delivery volume between the slurry inlet hydraulic pump and the slurry discharge hydraulic pump under the same pressure, the slurry discharge of the second conveying module is not completed at this time;

[0071] S7. Repeat steps S3 to S6.

[0072] In the above process, the slurry inlet critical switch and the slurry discharge critical switch are signals for controlling the start and stop of the hydraulic cylinder. Especially after the slurry discharge critical switch is triggered, it is necessary to start the waiting hydraulic cylinder first, and then cut off the power source of the hydraulic cylinder that currently triggers the critical switch. Therefore, the position of the slurry discharge critical switch must fully consider the time required for the two hydraulic valve actions to make the system run smoother and safer.

[0073] Of course, there can also be two independent slurry discharge hydraulic pumps to control the first hydraulic cylinder 10 and the second hydraulic cylinder 20 respectively, but the system will be more complicated. In this case, in order to ensure the stability of the material conveying speed in the slurry discharge pipe 32, it is necessary to separately control the delivery oil volume of the two slurry discharge hydraulic pumps. At this time, it is difficult to ensure the control accuracy by simply using limit switches, etc., so a linear sensor is needed to detect the position and speed of the piston in the hydraulic cylinder. Based on the monitoring of the piston movement speed, it is ensured that the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are in the slurry discharge process at the same time, and the total slurry discharge volume of the two is the same as the slurry discharge volume of a single set of conveying modules.

[0074] Embodiment 2:-

[0075] Different from the first embodiment, Figure 7 As shown, in this example, a linear sensor is used to replace the limit switch, that is, a first linear sensor 33 is provided on the first hydraulic cylinder 10, and a second linear sensor 34 is provided on the second hydraulic cylinder 20. In addition to measuring the position of the piston or plunger in the corresponding hydraulic cylinder, the linear sensor can also measure the speed of the piston or plunger. When the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are controlled by two independent slurry discharge hydraulic pumps, more precise control can be performed to ensure the stability of the transportation in the slurry discharge pipe 32.

[0076] Embodiment three:

[0077] Different from the first embodiment, Figure 8 As shown, the slurry inlet valve and the slurry discharge valve in this example are simple mechanical one-way valves, which are automatically opened and closed by the pressure difference on both sides of the valve core. In this way, the control logic is relatively simple.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A two-cylinder hydraulic continuous delivery pump, characterized in that: It comprises at least two sets of conveying modules, each of which comprises a hydraulic cylinder and a conveying cylinder, wherein a piston or a plunger is arranged in the conveying cylinder, and the hydraulic cylinder is used to drive the piston or the plunger in the conveying cylinder to make a reciprocating motion; The rodless chamber of the conveying cylinder is connected to the slurry inlet pipe via the slurry inlet valve, and the rodless chamber of the conveying cylinder is also connected to the slurry discharge pipe via the slurry discharge valve. When the slurry inlet valve or the slurry discharge valve is completely closed, the slurry discharge valve or the slurry inlet valve starts to open, ensuring that at any time, the rodless chamber of the conveying cylinder will not be connected to the slurry inlet pipe and the slurry discharge pipe at the same time; The two hydraulic cylinders in the two conveying modules are independently controlled, and the duration of the slurry feeding process is shorter than the duration of the slurry discharging process.

2. The two-cylinder hydraulic continuous delivery pump according to claim 1, characterized in that: A piston is arranged inside the delivery cylinder, and a vent pipe communicating with the atmosphere is arranged in the rod chamber of the delivery cylinder near one end of the oil cylinder.

3. The two-cylinder continuous drive hydraulic piston pump according to claim 1 or 2, characterized in that: The hydraulic cylinder is connected to the slurry discharge hydraulic pump and the slurry feed hydraulic pump via a hydraulic control valve, and the hydraulic cylinder switches between three states: connected to the slurry discharge hydraulic pump, not connected to any hydraulic pump, and connected to the slurry feed hydraulic pump; The slurry discharge hydraulic pump drives the piston in the hydraulic cylinder to move toward the delivery cylinder to achieve slurry discharge; The slurry feeding hydraulic pump drives the piston in the hydraulic cylinder to move away from the delivery cylinder to achieve the slurry feeding action; The amount of hydraulic oil output per unit time by the slurry discharge hydraulic pump is less than the amount of hydraulic oil output per unit time by the slurry feed hydraulic pump.

4. The two-cylinder hydraulic continuous delivery pump according to claim 3, characterized in that: The slurry discharge valve and the slurry inlet valve are respectively provided with valve switch in place sensors for detecting whether the valves are in place.

5. The two-cylinder hydraulic continuous delivery pump according to claim 4, characterized in that: The hydraulic control valve will only operate after the control system receives the signal from the valve closing position sensor to control the next action of the hydraulic cylinder.

6. The two-cylinder hydraulic continuous delivery pump according to any one of claims 1, 2, 4 and 5, characterized in that: The slurry inlet valve and slurry discharge valve of the first set of conveying modules and the slurry inlet valve and slurry discharge valve of the second set of conveying modules are independently controlled, that is, four independent control mechanisms control the slurry inlet valve and slurry discharge valve in the two sets of conveying modules respectively; Alternatively, the slurry inlet valve and the slurry discharge valve are mechanical one-way valves, which are automatically opened and closed by the pressure difference on both sides of the valve core.

7. The two-cylinder hydraulic continuous delivery pump according to any one of claims 1, 2, 4 and 5, characterized in that: The slurry inlet valve and the slurry discharge valve are a type of conical valve, flat valve or ball valve.

8. The two-cylinder hydraulic continuous delivery pump according to any one of claims 1, 2, 4 and 5, characterized in that: The hydraulic cylinder or the conveying cylinder is also provided with a slurry feeding critical detection module and a slurry discharging critical detection module.

9. The two-cylinder hydraulic continuous delivery pump according to claim 8, characterized in that: The conveying module is also equipped with a slurry entry limit detection module and a slurry discharge limit detection module, which are used to sense whether the piston in the hydraulic cylinder has reached the slurry entry limit point and the slurry discharge limit point. The slurry entry limit point corresponds to the position where the slurry entry is completed, and the slurry discharge limit point corresponds to the position where the slurry discharge is completed.

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