Two-cylinder hydraulic continuous delivery pump

Abstract

The utility model discloses a two-cylinder hydraulic continuous delivery pump, which comprises at least two sets of delivery modules, the two sets of delivery modules respectively comprise a hydraulic cylinder and a delivery cylinder, a piston or a plunger is arranged in the delivery cylinder, and the hydraulic cylinder is used for driving the piston or the plunger in the delivery cylinder 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 solution relates to the field of volume pumps, in particular to a two-cylinder hydraulic continuous conveying pump. BACKGROUND

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

[0003] Similar to concrete pumps, filling pumps, ceramic plunger pumps, etc., due to the need for high pressure in the application scene, hydraulic pressure is often used as the power source, and 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 comprises 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 reciprocate, and the second hydraulic cylinder drives the piston in the second conveying cylinder to reciprocate. The rod cavities of the first hydraulic cylinder and the second hydraulic cylinder are connected together through a pipeline. The rodless cavities of the first conveying cylinder and the second conveying cylinder are also connected to the slurry inlet pipe or the slurry outlet pipe under the control of the slurry inlet valve and the slurry outlet valve, and at any moment 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 outlet pipe.

[0004] More specifically, as shown in Figure 1 The rodless cavities of the first conveying cylinder and the second conveying cylinder are connected to the slurry inlet pipe through the slurry inlet valve and to the slurry outlet pipe through the slurry outlet valve. The slurry inlet valve and the slurry outlet valve are linked together. When the slurry inlet valve and the slurry outlet valve are in place, the same conveying cylinder can only be connected to one of the slurry inlet pipe or the slurry outlet pipe, and cannot be connected to both the slurry inlet pipe and the slurry outlet pipe at the same time. When the slurry inlet valve and the slurry outlet valve are in place, only one of the conveying cylinders is connected to the slurry inlet pipe, and only one of the conveying cylinders is connected to the slurry outlet pipe.

[0005] The above-mentioned pump has the characteristics of fewer cylinders, simple structure and easy control. However, since the two hydraulic cylinders are in series, they must act at the same time. Therefore, during the reversing period, the slurry inlet valve and the slurry outlet valve must be in place, and during the waiting process, the hydraulic cylinder cannot act, i.e. the conveying of the material is in a suspended state, which on the one hand leads to a decrease in the conveying efficiency of the material, and on the other hand, the sudden stop of the material can cause an impact on the pipeline, causing vibration of the equipment and the pipeline, and the conveyed slurry is prone to sedimentation in the pipeline.

[0006] Therefore, it is necessary to develop a two-cylinder hydraulic continuous conveying pump. CONTENT OF THE INVENTION

[0007] The utility model wants to solve the technical problem of how to overcome the problem of stopping conveying materials during the reversing of the existing hydraulic conveying pump.

[0008] The specific technical scheme for solving the above technical problem is:

[0009] A two-cylinder hydraulic continuous conveying pump comprises at least two sets of conveying modules, each of which comprises a hydraulic cylinder and a conveying cylinder, a piston or a plunger is arranged in the conveying cylinder, and the hydraulic cylinder is used for driving the piston or the plunger in the conveying cylinder to make reciprocating motion.

[0010] The rodless cavity of the conveying cylinder is connected to the pulp inlet pipe through a pulp inlet valve, and the rodless cavity of the conveying cylinder is also connected to the pulp outlet pipe through a pulp outlet valve; the pulp inlet valve and the pulp outlet valve are interlocked and controlled, and the pulp inlet valve and the pulp outlet valve are independently controlled; when the pulp inlet valve or the pulp outlet valve is completely closed, the pulp outlet valve or the pulp inlet valve is started to ensure that the rodless cavity of the conveying cylinder is not connected to the pulp inlet pipe and the pulp outlet pipe at the same time at any time; the two hydraulic cylinders in the two sets of conveying modules are independently controlled, and the length of the pulp inlet process is less than the length of the pulp outlet process.

[0011] The present scheme has the following beneficial effects compared with the prior art:

[0012] Since the length of the pulp inlet process is less than the length of the pulp outlet process, when the first group of conveying modules is still in the pulp outlet process, the second group of conveying modules has completed the pulp inlet process, the pulp inlet valve of the second group of conveying modules is closed, the pulp outlet valve of the second group of conveying modules is opened, and when the first group of conveying modules gradually ends the pulp outlet, the second group of conveying modules gradually starts to relay the pulp outlet;

[0013] During the pulp outlet process of the second group of conveying modules, the pulp outlet valve of the first group of conveying modules is closed, the pulp inlet valve of the first group of conveying modules is opened, the first group of conveying modules starts to inlet pulp, and before the pulp outlet of the second group of conveying modules is completed, the pulp inlet valve of the first group of conveying modules is closed, the pulp outlet valve of the first group of conveying modules is opened, and the first group of conveying modules waits for the pulp outlet of the second group of conveying modules to be completed to relay the pulp outlet;

[0014] In this way, the two groups of conveying modules act alternately, so that the pulp in the pulp outlet pipe can be continuously conveyed without stopping, the vibration of the pipeline and equipment caused by the intermittent conveying of the material in the pulp outlet pipe is avoided, the deposition of the pulp in the pipeline during the stoppage of the pulp is avoided, and the conveying efficiency of the pulp is improved.

[0015] Further, the rod cavity of the conveying cylinder is provided with an air vent pipe close to one end of the oil cylinder.

[0016] Further, the conveying cylinder is provided with a piston, and the oil cylinder is provided with a piston, which has the advantage that the piston is lighter in weight than the plunger.

[0017] Further, the hydraulic cylinder is connected with the discharge hydraulic pump and the intake hydraulic pump through the hydraulic control valve, and the hydraulic cylinder is switched among three states of being connected with the discharge hydraulic pump, not being connected with any hydraulic pump and being connected with the intake hydraulic pump; the discharge hydraulic pump drives the piston in the hydraulic cylinder to move towards the direction close to the delivery cylinder to realize the discharge action, and the intake hydraulic pump drives the piston in the hydraulic cylinder to move towards the direction away from the delivery cylinder to realize the intake action; the output of the discharge hydraulic pump in unit time is less than the output of the intake hydraulic pump in unit time;

[0018] Further, the valve switch in place sensor is arranged on the discharge valve and the intake valve respectively to detect whether the valves are switched in place.

[0019] Further, the hydraulic cylinder or the delivery cylinder is further provided with an intake critical detection module and a discharge critical detection module.

[0020] During the intake, the intake critical detection module is triggered, the intake hydraulic pump is disconnected, the intake valve is closed and the discharge valve is opened; after receiving the signal of the opening of the discharge valve and the signal sent by the discharge critical detection module, the discharge hydraulic pump is connected.

[0021] During the discharge, the discharge critical detection module is triggered, the discharge hydraulic pump is disconnected, the discharge valve is closed and the intake valve is opened; after receiving the signal of the opening of the intake valve, the intake hydraulic pump is connected.

[0022] Further, the delivery module is further provided with an intake limit detection module and a discharge limit detection module to sense whether the hydraulic cylinder reaches the intake limit point and the discharge limit point; the intake limit point and the discharge limit point are the over-limit positions allowed to be reached by the piston during operation. After receiving the signal, it is indicated that the piston of the hydraulic cylinder may hit the cylinder, and the position of the intake critical detection module or the discharge critical detection module needs to be adjusted to make the hydraulic cylinder act earlier until no signal is received, so as to ensure the safety of the system.

[0023] The intake limit detection module, the discharge limit detection module, the intake critical detection module and the discharge critical detection module can be limit switches, proximity switches, linear sensors, photoelectric switches and the like. In addition to measuring the position of the piston or the plunger in the hydraulic cylinder, the linear sensor can also measure the speed of the piston or the plunger.

[0024] Further, the signals of the valve switch in place sensor, the intake critical detection module and the discharge critical detection module are communicated with the hydraulic control valve, and the hydraulic control valve will act only after the control system receives the signal of the valve switch in place sensor to control the next action of the hydraulic cylinder.

[0025] When the first set of conveying module is feeding, the feeding critical detection module is triggered, then the connection between the hydraulic cylinder of the first set of conveying module and the feeding hydraulic pump is disconnected, the feeding valve of the first set of conveying module is closed, the discharge valve of the first set of conveying module is opened, after receiving the signal of the opening of the discharge valve of the first set of conveying module and the signal of the triggering of the discharge critical detection module of the second set of conveying module, the system controls the connection between the hydraulic cylinder of the first set of conveying module and the discharge hydraulic pump, and the feeding starts;

[0026] When the second set of conveying module is discharging, after receiving the signal of the triggering of the discharge critical detection module of the second set of conveying module, the system opens the connection between the hydraulic cylinder of the first set of conveying module and the discharge hydraulic pump, disconnects the connection between the hydraulic cylinder of the second set of conveying module and the discharge hydraulic pump, closes the discharge valve of the second set of conveying module, after receiving the signal of the closing of the discharge valve of the second set of conveying module, opens the feeding valve of the second set of conveying module, after receiving the signal of the opening of the feeding valve of the second set of conveying module, the system controls the connection between the hydraulic cylinder of the second set of conveying module and the feeding hydraulic pump, and the feeding starts;

[0027] Further, the feeding valve and the discharge valve of the first set of conveying module and the feeding valve and the discharge valve of the second set of conveying module are independently controlled, that is, there are four independent control mechanisms to control the feeding valve and the discharge valve in the two sets of conveying modules, or the feeding valve and the 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 feeding valve and the discharge valve are mechanical one-way valves, there is no need to wait for the signal of the opening and closing of the feeding valve and the discharge valve during the whole process.

[0028] Further, the feeding valve and the discharge valve are one of a conical valve, a flat valve and a ball valve.

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

[0030] Further, when the feeding limit module or the discharge limit module receives a signal, it represents that the running distance of the hydraulic cylinder after being closed is too long, and the piston may hit the hydraulic cylinder, so it is necessary to adjust the position of the feeding critical detection module or the discharge critical detection module to execute the instruction of "cutting off the action of the hydraulic cylinder" earlier to ensure that the feeding limit module or the discharge limit module is not triggered in the normal process, and to ensure the safety of the system. BRIEF DESCRIPTION OF DRAWINGS

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

[0032] Figure 2 It is a schematic diagram of the initial state of the two-cylinder hydraulic continuous conveying pump before starting

piston + piston

[0033] Figure 3Figure 1 is a schematic diagram of the first conveying module standby and the second conveying module independent discharge of slurry in the embodiment one;

[0034] Figure 4 Figure 2 is a schematic diagram of the first conveying module and the second conveying module simultaneous discharge of slurry in the embodiment one;

[0035] Figure 5 Figure 3 is a schematic diagram of the first conveying module independent discharge of slurry and the second conveying module closed discharge of slurry in the embodiment one;

[0036] Figure 6 Figure 4 is a schematic diagram of the first conveying module independent discharge of slurry and the second conveying module feeding of slurry in the embodiment one;

[0037] Figure 7 Figure 5 is a schematic diagram of the two-cylinder continuous driving hydraulic piston pump in the embodiment two

linear sensor

[0038] Figure 8 Figure 6 is a schematic diagram of the two-cylinder continuous driving hydraulic piston pump in the embodiment three

one-way valve

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

[0040] 10, first hydraulic cylinder; 11, first conveying cylinder; 12, first feeding valve; 13, first discharging valve; 14, first support; 15, first oil feeding pipe; 16, first piston; 171, first discharging limit switch; 172, first discharging critical switch; 173, first feeding critical switch; 174, first feeding limit switch; 18, first piston rod; 19, first oil discharging pipe;

[0041] 20, second hydraulic cylinder; 21, second conveying cylinder; 22, second feeding valve; 23, second discharging valve; 24, second support; 25, second oil feeding pipe; 26, second piston; 271, second discharging limit switch; 272, second discharging critical switch; 273, second feeding critical switch; 274, second feeding limit switch; 28, second piston rod; 29, second oil discharging pipe;

[0042] 30, communication oil pipe; 31, feeding pipe; 32, discharging pipe; 33, first linear sensor; 34, second linear sensor. DETAILED DESCRIPTION

[0043] The principles and characteristics of the utility model are described below in combination with the drawings, and the examples are only used to explain the utility model and are not used to limit the scope of the utility model. In the description of the embodiments of the utility model, it should be explained that if the directions or position relations of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like are shown based on the directions or position relations shown in the drawings or the directions or position relations of the utility model product in common use, they are only used to facilitate the description of the utility model and simplify the description, and they cannot be understood as indicating or implying that the indicated devices or elements must have a specific direction, a specific direction structure and operation, and therefore they cannot be understood as limiting the utility model. In addition, "first", "second", "third" and the like in the technical feature names are only used to distinguish the description, and cannot be understood as indicating or implying relative importance, nor containing order relations.

[0044] As shown in Figure 1 It is a conveying cylinder in the prior art, and the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are both provided with a piston, the rodless cavity of the hydraulic cylinder is communicated with an oil feeding pipe, the rod cavity of the hydraulic cylinder is communicated with an oil discharging pipe, the oil discharging pipes of the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are communicated together through a communication pipe 30, that is, the rod cavities of the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are communicated together;

[0045] The rodless cavities of the first conveying cylinder 11 and the second conveying cylinder 21 are connected to a pulp feeding pipe 31 through a pulp feeding valve and connected to a pulp discharging pipe 32 through a pulp discharging valve, the pulp feeding valve and the pulp discharging valve are linked, when the pulp feeding valve and the pulp discharging valve are in place, the same conveying cylinder can only be communicated with one of the pulp feeding pipe 31 or the pulp discharging pipe 32, and cannot be communicated with both the pulp feeding pipe 31 and the pulp discharging pipe 32 at the same time, and when the pulp feeding valve and the pulp discharging valve are in place, only one conveying cylinder is communicated with the pulp feeding pipe 31, and only one conveying cylinder is communicated with the pulp discharging pipe 32.

[0046] The two driving hydraulic cylinders are in series, due to the incompressibility of the hydraulic oil, both of them must act at the same time, for example, when the piston in the first hydraulic cylinder 10 moves upward, the space of the rod cavity of the first hydraulic cylinder 10 increases, and the hydraulic oil in the rod cavity will be transferred from the rod cavity of the second hydraulic cylinder 20 to the rod cavity 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, the next action of the hydraulic cylinder must be started after the pulp feeding valve and the pulp discharging valve are completely in place, and during this waiting process, the hydraulic cylinder cannot act, and the conveying of the material is in a suspended state, which leads to the reduction of the conveying efficiency of the material on the one hand, and the sudden stop of the material can also cause impact on the pipeline, causing vibration of the equipment and the pipeline, and the conveying slurry is also easy to deposit in the pipeline.

[0047] As shown in Figure 2An embodiment of the hydraulic continuous conveying pump is shown in the utility model:

[0048] A two-cylinder hydraulic continuous conveying pump comprises two sets of conveying modules with the same size, and each set of the conveying modules comprises a hydraulic cylinder and a conveying cylinder, i.e. the first set of conveying modules comprises a first hydraulic cylinder 10, a first support 14 and a first conveying cylinder 11, and the second set of conveying modules comprises a second hydraulic cylinder 20, a second support 24 and a second conveying cylinder 21; a piston is arranged in each of the hydraulic cylinder and the conveying cylinder; specifically, a first piston 16 is arranged in the first conveying cylinder 11, and a second piston 26 is arranged in the second conveying cylinder 21; the first piston 16 is connected to the piston in the first hydraulic cylinder 10 through a first piston rod 18, and the second piston 26 is connected to the piston in the second hydraulic cylinder 20 through a second piston rod 28; the hydraulic cylinder is used for driving the piston in the conveying cylinder to make reciprocating motion; and a vent pipe for communicating with the atmosphere is arranged on the rod cavity of the conveying cylinder close to one end of the oil cylinder.

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

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

[0051] The first pulp feeding valve 12 and the first pulp discharging valve 13 are interlocked, the second pulp feeding valve 22 and the second pulp discharging valve 23 are interlocked, and the first pulp feeding valve 12 and the second pulp feeding valve 22 are independently controlled with the first pulp discharging valve 13 and the second pulp discharging valve 23, respectively. When the pulp feeding valve or the pulp discharging valve is completely closed, the pulp discharging valve or the pulp feeding valve starts to open, ensuring that at any time, the rodless cavity of the delivery cylinder is not connected to the pulp feeding pipe 31 and the pulp discharging pipe 32 at the same time. Because the simultaneous connection of the rodless cavity to the pulp feeding pipe 31 and the pulp discharging pipe 32 means that the pulp feeding pipe 31 and the pulp discharging pipe 32 are connected together, and during normal operation, the pressure of the pulp discharging pipe 32 is greater than that of the pulp feeding pipe 31, the connection of the two means that the material in the pulp discharging pipe 32 will be pushed back into the pulp feeding pipe 31, which is an undesirable result. The two hydraulic cylinders in the two delivery modules are independently controlled, and the pulp feeding time is shorter than the pulp discharging time, which is a very core link. This can realize the seamless connection of the pulp discharging action of the two delivery modules. During the pulp discharging process of the first delivery cylinder 11, the second delivery cylinder 21 completes the pulp feeding action in a time shorter than the pulp discharging time, and waits for the first delivery cylinder 11 to complete the pulp discharging. Once the first delivery cylinder 11 completes the pulp discharging, the second delivery cylinder 21 seamlessly connects and immediately follows up the pulp discharging. At the same time, the first delivery cylinder 11 switches to pulp feeding, and the cycle is repeated to realize continuous delivery of the material.

[0052] Further, the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are controlled by the hydraulic control valve to connect the pulp discharging hydraulic pump and the pulp feeding hydraulic pump. The first hydraulic cylinder 10 and the second hydraulic cylinder 20 are switched between the three states of connecting the pulp discharging hydraulic pump, not connecting any hydraulic pump, and connecting the pulp feeding hydraulic pump. The pulp discharging hydraulic pump drives the piston in the hydraulic cylinder to move towards the delivery cylinder to realize the pulp discharging action. The pulp feeding hydraulic pump drives the piston in the hydraulic cylinder to move away from the delivery cylinder to realize the pulp feeding action. The output of the pulp discharging hydraulic pump per unit time is less than that of the pulp feeding hydraulic pump per unit time. In the case that the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are equal in size, the pulp feeding time can be shorter than the pulp discharging time. Or the output of the pulp discharging hydraulic pump per unit time is equal to that of the pulp feeding hydraulic pump per unit time. In the case that the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are equal in size, because the area of the hydraulic oil in the dry cavity is small (part of the area is occupied by the hydraulic rod), the running speed will be faster under the same oil volume, and the pulp feeding time can be shorter than the pulp discharging time.

[0053] Further, the discharge valve and the inlet valve are respectively provided with valve opening and closing position sensors for detecting whether the valve is opened or closed, the first discharge valve 13 and / or the second discharge valve 23 can be opened only when the first inlet valve 12 and the second inlet valve 22 are completely closed, and the first inlet valve 12 and / or the second inlet valve 22 can be opened only when the first discharge valve 13 and the second discharge valve 23 are completely closed, so as to ensure that the inlet pipe 31 and the discharge pipe 32 are not connected at any time.

[0054] Further, the inlet limit detection module, the discharge limit detection module, the inlet critical detection module and the discharge critical detection module are provided, the inlet critical detection module is located on the side of the inlet limit detection module close to the discharge limit detection module, and the discharge critical detection module is located on the side of the discharge limit detection module close to the inlet limit detection module; when the inlet critical detection module and the discharge critical detection module are triggered, the power source of the hydraulic cylinder is cut off, and the opening and closing of the brake valve of the hydraulic cylinder is performed.

[0055] The inlet limit detection module and the discharge limit detection module are used for sensing whether the hydraulic cylinder reaches the inlet limit point and the discharge limit point, the inlet limit point and the discharge limit point are the limit positions allowed to be reached when the piston operates, the inlet limit point corresponds to the position of completing the inlet, and the discharge limit point corresponds to the position of completing the discharge; under normal circumstances, the inlet limit detection module and the discharge limit detection module are not allowed to be triggered, and once triggered, it means that the hydraulic cylinder has the risk of cylinder collision, so if the inlet limit detection module or the discharge limit detection module is triggered in daily work, it means that the time of cutting off the power source of the hydraulic cylinder is too late, and the position of the inlet critical detection module or the discharge critical detection module needs to be adjusted to ensure that the inlet limit detection module or the discharge limit detection module is not triggered.

[0056] In this example, the limit switches are used to detect the positions, that is, the first hydraulic cylinder 10 is provided with a first inlet limit switch 174, a first discharge limit switch 171, a first inlet critical switch 173 and a first discharge critical switch 172, and the second hydraulic cylinder 20 is provided with a second inlet limit switch 274, a second discharge limit switch 271, a second inlet critical switch 273 and a second discharge critical switch 272.

[0057] The pulp feeding critical switch is triggered, which means that the pulp feeding is completed. The hydraulic control valve is actuated to close the connection between the hydraulic cylinder for pulp feeding and the pulp feeding hydraulic pump, and the hydraulic cylinder for pulp feeding stops working. The corresponding pulp feeding valve is closed, and the corresponding pulp discharge valve is opened. The hydraulic cylinder for pulp discharge is waiting for the trigger of the corresponding pulp discharge critical switch. After the pulp discharge critical switch is triggered, it means that the pulp discharge is about to end. At this time, the pulp discharge hydraulic pump keeps the hydraulic oil delivery rate unchanged. First, the hydraulic cylinder on the pulp discharge side that has completed the pulp feeding action is connected to the pulp discharge hydraulic pump, that is, the hydraulic control valve controls the two hydraulic cylinders to be connected to the pulp discharge hydraulic pump at the same time. The two hydraulic cylinders jointly receive the hydraulic oil originally supplied by the pulp discharge hydraulic pump to one hydraulic cylinder. Then, the connection between the hydraulic cylinder on the pulp discharge critical switch side and the pulp discharge hydraulic pump is disconnected. Finally, the corresponding pulp discharge valve on the pulp discharge critical switch side is closed. In this way, the first hydraulic cylinder 10 and the second hydraulic cylinder 20 realize seamless and smooth switching. The pulp discharge action is switched between the two sets of conveying modules. The pulp 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 delivery rate of the pulp discharge hydraulic pump is always kept unchanged, the material in the pulp discharge pipe 32 always maintains a constant conveying speed during the switching of the conveying cylinders, and there is no situation of fast and slow. This reduces the impact on the pipeline. In order to ensure safety, once the pulp feeding limit switch and the pulp discharge limit switch are triggered, the connection between the corresponding hydraulic cylinder and the hydraulic pump is immediately cut off, and the action of the hydraulic cylinder is stopped.

[0058] The pulp feeding critical detection module and the pulp discharge critical detection module can also be proximity switches, linear sensors, photoelectric switches, etc. Their installation positions are not limited to the hydraulic cylinder, but 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 pulp feeding valves and the pulp discharge valves of the first set of conveying modules and the pulp feeding valves and the pulp discharge valves of the second set of conveying modules are independently controlled, that is, there are four independent control mechanisms to control the pulp feeding valves and the pulp discharge valves in the two sets of conveying modules. The pulp feeding valves and the pulp discharge valves can be one of a conical valve, a flat valve, and a ball valve. The control of the pulp feeding valves and the pulp discharge valves can be driven by one of a motor, an electromagnetic drive, a hydraulic drive, and a pneumatic drive.

[0060] The action of the hydraulic control valve is generally completed within a few milliseconds to a few tens of milliseconds. However, the opening and closing of the pulp feeding valve and the pulp discharge valve require a few seconds to a few dozen seconds. In order to meet this time requirement, the pulp feeding pipe and the pulp discharge pipe are not connected during the switching.

[0061] The use process of the two-cylinder continuous driving hydraulic piston pump is as follows:

[0062] For example 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 to close the communication between the first hydraulic cylinder 10 and the pulp feeding hydraulic pump, stop the pulp feeding operation, close the first pulp feeding valve 12, cut off the communication between the first conveying cylinder 11 and the pulp feeding pipe 31, and then open the first pulp discharging valve 13. 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 communicate with the pulp discharging hydraulic pump, and the first conveying module starts to perform the pulp discharging operation. Then, the communication between the second hydraulic cylinder 20 and the pulp discharging hydraulic pump is cut off. Since the communication between the first hydraulic cylinder 10 and the pulp discharging hydraulic pump is opened first and then the communication between the second hydraulic cylinder 20 and the pulp discharging hydraulic pump is cut off, both sets of conveying modules are discharging pulp during this period, but the total oil flow rate depends on the operation of the pulp discharging hydraulic pump, so it is equal to the oil flow rate when the single conveying module discharges pulp, which ensures the stability of the material conveying speed in the pulp discharging pipe 32. Then, the second pulp discharging valve 23 of the second conveying module is gradually closed. After the second pulp discharging valve 23 of the second conveying module is completely closed, the second pulp feeding valve 22 is immediately opened, the second hydraulic cylinder 20 is connected to the pulp feeding hydraulic pump, and the second conveying module starts to perform the pulp feeding operation. The above operation is repeated to realize continuous and uninterrupted conveying of the material.

[0063] The more complete use method is as follows:

[0064] Method steps:

[0065] S1, initial state setting, close all pulp discharging valves, open all pulp feeding valves, and the hydraulic cylinders of the second conveying module and the first conveying module are simultaneously or separately retracted to realize the pulp feeding of the conveying cylinder, as shown. Figure 2 After detecting that the conveying cylinder completes the pulp feeding, such as triggering the pulp feeding critical switch and / or the pulp feeding limit switch, the drive of all hydraulic cylinders is stopped.

[0066] S2, close all pulp feeding valves, then open the pulp discharging valve of the second conveying module, and after the pulp discharging valve of the second conveying module is opened to the position, control the hydraulic cylinder of the second conveying module to communicate with the pulp discharging hydraulic pump to discharge the material in the conveying cylinder of the second conveying module into the pulp discharging pipe 32, as shown. Figure 3

[0067] S3, without waiting for the pulp discharging of the second conveying module to be completed, the pulp discharging valve of the first conveying module is opened. Here, as long as the first pulp feeding valve 12 in the first conveying module is completely closed, the first pulp discharging valve 13 of the first conveying module can be opened to make the first conveying cylinder 11 of the first conveying module communicate with the pulp discharging pipe 32, as shown. Figure 4 ​As shown, after receiving the signal that the second discharge critical switch 272 of the second conveying module is triggered, meaning that the second conveying module is about to complete the discharge action, the first hydraulic cylinder 10 of the first conveying module is connected to the discharge hydraulic pump, and then the second hydraulic cylinder 20 of the second conveying module is disconnected from the discharge hydraulic pump, so as to continuously discharge the material in the first conveying cylinder to the discharge pipe 32; then the second discharge valve 23 of the second conveying module is closed, as shown. Figure 5

[0068] S4, after the second discharge valve 23 of the second conveying module is closed in place, the second inlet valve 22 of the second conveying module is opened, the second hydraulic cylinder 20 of the second conveying module is connected to the inlet hydraulic pump, and the rapid inlet of the second conveying module is realized, as shown. Figure 6

[0069] S5, without waiting for the first conveying module to complete the discharge, the second discharge valve 23 of the second conveying module is opened, here, as long as the second inlet valve 22 of the second conveying module is completely closed, the second discharge valve 23 of the second conveying module can be opened, so that the second conveying cylinder 21 of the second conveying module is connected to the discharge pipe 32, after receiving the signal that the first discharge critical switch 172 of the first conveying module is triggered, meaning that the first conveying module is about to complete the discharge action, the second hydraulic cylinder 20 of the second conveying module is connected to the discharge hydraulic pump, so as to continuously discharge the material in the second conveying cylinder to the discharge pipe 32, and then the first hydraulic cylinder 10 of the first conveying module is disconnected from the discharge hydraulic pump; then the first discharge valve 13 of the first conveying module is closed.

[0070] S6, after the first discharge valve 13 of the first conveying module is closed in place, the first inlet valve 12 of the first conveying module is opened, the first hydraulic cylinder 10 of the first conveying module is connected to the inlet hydraulic pump, and the rapid inlet of the first conveying module is realized; after the first inlet critical switch 173 of the first conveying module is triggered, the first hydraulic cylinder 10 is disconnected from the inlet hydraulic pump, the first inlet valve 12 of the first conveying module is closed, and the inlet is stopped; based on the difference in oil delivery amount of the inlet hydraulic pump and the discharge hydraulic pump under the same pressure, the discharge of the second conveying module is still not completed at this time.

[0071] S7, repeat steps S3 to S6.

[0072] ​​In the above process, the pulp feeding critical switch and the pulp discharging critical switch are signals for controlling the start and stop of the hydraulic cylinder, especially after the pulp discharging critical switch is triggered, the hydraulic cylinder in standby needs to be started first, and then the power source of the hydraulic cylinder triggering the critical switch is cut off, so the position of the pulp discharging critical switch needs to fully consider the time required for the two hydraulic valve actions to make the system run more smoothly and safely.

[0073] Of course, there can also be two independent pulp discharging hydraulic pumps to control the first hydraulic cylinder 10 and the second hydraulic cylinder 20, but the system will be more complex, in this case, in order to ensure the stability of the material conveying speed in the pulp discharging pipe 32, the conveying oil quantity of the two pulp discharging hydraulic pumps needs to be controlled separately, at this time, it is difficult to ensure the control accuracy by simply using limit switches, and a linear sensor needs to be used to detect the position and speed of the piston in the hydraulic cylinder, based on the monitoring of the piston movement speed, to ensure that the first hydraulic cylinder 10 and the second hydraulic cylinder 20 are in the pulp discharging process at the same time, and the total pulp discharging quantity of the two is the same as the pulp discharging quantity of a single conveying module.

[0074] Example two:

[0075] Different from example one, as shown in Figure 7 , in this example, a linear sensor is used instead of a limit switch, that is, a first linear sensor 33 is arranged on the first hydraulic cylinder 10, and a second linear sensor 34 is arranged on the second hydraulic cylinder 20, the linear sensor can measure the position and speed of the piston or plunger in the corresponding hydraulic cylinder. When two independent pulp discharging hydraulic pumps are used to control the first hydraulic cylinder 10 and the second hydraulic cylinder 20, the control can be more accurate, and the stability of the conveying in the pulp discharging pipe 32 can be ensured.

[0076] Example three:

[0077] Different from example one, as shown in Figure 8 , in this example, the pulp feeding valve and the pulp discharging valve are both simple mechanical one-way valves, which are automatically opened and closed by relying on the pressure difference on both sides of the valve core. In this way, the control logic is relatively simple.

[0078] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A two-cylinder hydraulic continuous delivery pump, characterized by, The device comprises at least two sets of conveying modules, each of which comprises a hydraulic cylinder and a conveying cylinder, and the conveying cylinder is provided with a piston or a plunger. The rodless cavity of the conveying cylinder is connected to the inlet pipe through an inlet valve, and is also connected to the outlet pipe through an outlet valve. The two hydraulic cylinders in the two sets of conveying modules are independently controlled, and the length of the inlet process is less than that of the outlet process.

2. The two-cylinder hydraulic continuous delivery pump according to claim 1, characterized in that, The conveying cylinder is provided with a piston, and the rod cavity of the conveying cylinder is provided with an air pipe close to one end of the oil cylinder.

3. The two-cylinder hydraulic continuous delivery pump according to claim 1 or 2, characterized in that The hydraulic cylinder is connected to the outlet hydraulic pump and the inlet hydraulic pump through a hydraulic control valve, and the hydraulic cylinder is switched between the three states of being connected to the outlet hydraulic pump, not being connected to any hydraulic pump, and being connected to the inlet hydraulic pump. The outlet hydraulic pump drives the piston in the hydraulic cylinder to move towards the conveying cylinder, thereby realizing the outlet action. The inlet hydraulic pump drives the piston in the hydraulic cylinder to move away from the conveying cylinder, thereby realizing the inlet action. The amount of hydraulic oil output by the outlet hydraulic pump per unit time is less than that of the inlet hydraulic pump.

4. The two-cylinder hydraulic continuous delivery pump according to claim 3, characterized in that, The outlet valve and the 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 of claim 4, wherein, After receiving the signal of the valve in-place sensor, the hydraulic control valve will act 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, 5, characterized in that, The inlet valves and outlet valves of the first set of conveying modules and the second set of conveying modules are independently controlled, i.e. there are four independent control mechanisms to control the inlet valves and outlet valves of the two sets of conveying modules. Alternatively, the inlet valve and the outlet valve are mechanical one-way valves that are automatically opened and closed by the pressure difference between the two sides of the valve core.

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

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

9. The two-cylinder hydraulic continuous delivery pump of claim 8, wherein, The conveying module is also provided with an inlet limit detection module and an outlet limit detection module for sensing whether the piston in the hydraulic cylinder reaches the inlet limit point and the outlet limit point, and the inlet limit point corresponds to the position of completing the inlet, and the outlet limit point corresponds to the position of completing the outlet.

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