Pump system for pumping a substance

Abstract

The application relates to a pump system (100) for pumping a substance. The pump system comprises pumping cylinders (112) and a swing pipe mechanism (114). Each pumping cylinder (112) is configured to load the substance, when said pumping cylinder is open to operate as a loading cylinder, and to push the substance from the pumping cylinder (112), when said pumping cylinder is closed to operate as a pushing cylinder. The swing pipe mechanism is configured to open one of the pumping cylinders for loading the substance to said pumping cylinder (112) and to close another of the pumping cylinders for directing the substance from said pumping cylinder (112) outside the pump system. The pump system further comprises a pump controller (134) for synchronizing the loading and the pushing of the substance of the pumping cylinders by means of the swing pipe mechanism comprises a swing pipe (116) for each pumping cylinder (112) so that the swing pipe mechanism is further configured to keep the pumping cylinders closed by means of the swing pipes (116) to push the substance from the pumping cylinders simultaneously for a moment for preventing an unwanted change in a substance flow outside the pump system during a change of the pushing cylinder.

Description

[0001] PUMP SYSTEM FOR PUMPING A SUBSTANCE

[0002] Technical field

[0003] The application relates generally to a pump system for pumping a substance.

[0004] Background

[0005] Spraying machines require concrete pumps to pump concrete to be sprayed from a hopper into a spraying hose before additives and pressurized air are added to the concrete flow in a spraying nozzle at an end of the spraying hose.

[0006] A known two-cylinder concrete pump comprises a hopper to receive the concrete, pumping cylinders to load the concrete from the hopper and to unload the concrete into the spraying hose, and a connection pipe to connect the spraying hose to the concrete pump. The concrete pump further comprises a swing pipe to connect a pumping cylinder that unloads the concrete to the connection pipe and to disconnect another pumping cylinder so that said pumping cylinder can reload the concrete.

[0007] The operation of the pumping cylinders, i.e. , the loading and unloading steps, is synchronized so that one pumping cylinder, which is disconnected from the connection pipe, loads (reloads) the concrete into said pumping cylinder while another pumping cylinder, which is connected to the connection pipe by means of the swing pipe, unloads the concrete through the swing and connection pipes to the spraying hose. When the loading cylinder has completed the loading of the concrete and the unloading cylinder has completed the unloading of the concrete, the roles of the pumping cylinders change and the pumping cylinder, which is fully loaded, changes as a unloading cylinder and another pumping cylinder, which is now empty, changes as a loading cylinder.

[0008] The operation of the pumping cylinders with the changing roles continues and the concrete to be sprayed by the spraying machine is pumped through the spraying hose to the spraying machine until the concrete pump is stopped.

[0009] Summary

[0010] One object of the invention is to withdraw the drawbacks of known solutions and to provide a pump system for a spraying machine, which operates reliably and is easy to maintain due to its simple and robust structure. The provided pump systemfurther enables to pump a substance to be sprayed without any unwanted (undesired) changes (variations) in a flow of the substance so that a quality of the sprayed substance does not decrease when additional substances are added to the pumped substance.

[0011] One object of the invention is fulfilled by providing the pump system, pumping method, computer program, and computer-readable medium according to the independent claims.

[0012] Embodiments of the invention are disclosed in the claims.

[0013] One pump system for pumping a substance comprises pumping cylinders and a swing pipe mechanism. Each pumping cylinder is configured to load the substance, when said pumping cylinder is open to operate as a loading cylinder, and to push the substance from the pumping cylinder, when said pumping cylinder is closed to operate as a pushing cylinder. The swing pipe mechanism is configured to open one of the pumping cylinders for loading the substance to said pumping cylinder and to close another of the pumping cylinders for directing the substance from said pumping cylinder outside the pump system. The pump system further comprises a pump controller for synchronizing the loading and the pushing of the substance of the pumping cylinders by means of the swing pipe mechanism, which comprises a swing pipe for each pumping cylinder so that the swing pipe mechanism is further configured to keep the pumping cylinders closed by means of the swing pipes to push the substance from the pumping cylinders simultaneously for a moment for preventing an unwanted change in (a decrease of) a substance flow outside the pump system during a change of the pushing cylinder.

[0014] One pumping method for pumping a substance by means of the previous pump system comprises following steps of opening, by the swing pipe mechanism, one of the pumping cylinders and closing, by the swing pipe mechanism, another of the pumping cylinders and loading, by said opened pumping cylinder operating as a loading cylinder, the substance. The pumping method further comprises following steps of pushing, by each closed pumping cylinder operating as a pushing cylinder, the substance from said pumping cylinder and directing, by the swing pipe mechanism, the substance from each closed pumping cylinder outside the pump system. The pump controller synchronizes the swing pipe mechanism to keep the pumping cylinders closed by means of the swing pipes to push the substance from the pumping cylinders simultaneously for a moment for preventing an unwantedchange in a substance flow outside the pump system during a change of the pushing cylinder.

[0015] One computer program comprises instructions, which, when the computer program is executed by a pump controller that comprises a processor, cause the previous pump system to carry out (perform) at least the steps of the previous pumping method.

[0016] One tangible, non-volatile computer readable medium comprises the previous computer program.

[0017] Brief description of the figures

[0018] The exemplary embodiments of the invention are explained with reference to the accompanying figures:

[0019] fig. 1 presents a pump machine and a pump system

[0020] fig. 2 presents the pump system from an opposite direction

[0021] fig. 3a-3e present a synchronization of loading and unloading steps of pumping cylinders

[0022] Detailed description of the figures

[0023] Fig. 1-2 present a pump system 100 that is configured to pump a substance, e.g., concrete, sludge, or biomass, to be pumped. The pump system 100, which is integrated in a pump machine 102, e.g., a mobile pump machine, comprises a simple and robust structure that ensures a reliable operation and easy maintenance.

[0024] The pump machine 102 is configured to be connected to a spraying machine by means of a spraying hose, which are not presented in the figures. The spraying machine is then configured to spray to the substance, which is pumped from the pump machine 102, without any weakening of a flow of the substance from the pump system 100.

[0025] The spraying machine is further configured to add additional substances, e.g., at least one additive, e.g., one, two, three, four, or more additives, and pressurized air to the pumped substance, whereupon the weakening of the substance flow, if such would exist, could cause a weakening of a quality of the substance every time when a relation of the pumped substance and the additional substances changes due to the decreased substance flow.The pump system 100 comprises a reservoir 104, e.g., a hopper, supply tank, or other supply means. The reservoir 104 is configured to receive the substance outside the pump machine 102, i.e., outside the pump system 100, and to store briefly (temporarily) the received substance before the reservoir 104 allows the pump system 100 to direct (unload) the substance outside the pump system 100.

[0026] The reservoir 104 comprises a bottom 206 and at least one side 208, e.g., one, two, three, four, ot more sides 208, which form an interior 210. The reservoir 104 further comprises an open upper (top) part according to the figures so that the reservoir 104 is configured to receive the substance to be pumbed into its interior 210 from above.

[0027] The reservoir 104 further comprises openings, e.g., in the at least one side 208, that enable to connect pumping cylinders 112 to the interior 210 so that the pump system 100 is able to pump the substance outside the pump system 100.

[0028] The pump system 100 further comprises said pumping cylinders 112, e.g. two, three, four, five, or more pumping cylinders 112, that are connected to the reservoir 104. The pumping cylinders 112 comprise connections to the interior 210 through the openings of the reservoir 104. The pumping cylinders 112 are operated hydraulically.

[0029] Each pumping cylinder 210 is configured to operate as a loading cylinder and to load (reload) the substrate from the reservoir 104 that allow such operation, when the pumping cylinder 112 is open, i.e., in an open position OP. Each pumping cylinder 112 is further configured to operate as a pushing (unloading) cylinder 112 and to push (unload) the substrate from the pumping cylinder 112 outside the pump system 100, when said pumping cylinder is closed, i.e., in a closed position CL.

[0030] The pump system 100 further comprises a swing pipe mechanism 114 that is configured to open one of the pumping cylinders 112 at a time, i.e., to cause said pumping cylinder 112 in the open position OP, to load the substance into said opened pumping cylinder 112. The swing pipe mechanism 114 is further configured to close at least one of pumping cylinders 112 at a time, i.e., to cause said at least one pumping cylinder 112, e.g., one, two, three, four, or more pumping cylinders 112, in the closed position CL, which is loaded with the substance, and to direct the substance from said closed at least one pumping cylinder 112 outside the pump system 100.The swing pipe mechanism 114 comprises a swing pipe (swing tube, S-pipe, S-tube, S-pipe valve, S-tube valve) 116 for each pumping cylinder 112. Each swing pipe 116 is operated, e.g., hydraulically, pneumatically, mechanically, electrome-chanically, or eletrically.

[0031] The swing pipe mechanism 114 further comprises a bearing mechanism 124, a swing mechanism 130, and a sealing ring 332 for each swing pipe 116, which are configured to enable the swing pipe 116 to swing S between the open and closed positions OP, CL so that the pumping cylinder 112 is opened and closed.

[0032] The pump system 100 further comprises a connection pipe 118 that is connected to the swing pipes 116. The connection pipe 118 connects each pumping cylinder 112 by means of its swing pipe 116 to the spraying hose directly or by means of other connection means. The connection pipe 118 is configured to direct the substance outside the pump system 100 from each pumping cylinder 112 by means of the swing pipes 116.

[0033] The connection pipe 118 comprises a pipe structure that connects (integrates) its each branch, which arranges the connection to one swing pipe 116, into a main channel of the connection pipe 118. The connection pipe 118 comprises, e.g., a two-branch Y-pipe (Y-tube) 118 when the pump system 100 comprises two pumping cylinders 112 and the swing pipes 116 according to the figures, a three-branch wye-pipe when the pump system 100 comprises three pumping cylinders 112 and the swing pipes 116, a four-branch wye-pipe when the pump system 100 comprises four pumping cylinders 112 and the swing pipes 116, etc.

[0034] The pump system 100 further comprises an end mechanism 120 that connects a pipe end 222 of each swing pipe 116, which is towards the connection pipe 118 and away from the pumping cylinders 112, to the the branches of the connection pipe 118.

[0035] Each pipe end 222, i.e., each swing pipe 116, comprises the previously mentioned bearing mechanism 124, which is a part of the swing pipe mechanism 114. The bearing mechanism 124 is configured to allow the connected swing pipe 116, i.e., the pipe end 222 that is towards the connection pipe 118 and away from the pumping cylinders 112, to rotate R independently with respect to the reservoir 104 and the connection pipe 118 when a cylinder end 126 of the swing pipe 116, which is towards the pumping cylinders 112 and away from the connection pipe 118, is swinged S between the open and closed positions OP, CL.The pump system 100 further comprises a connection mechanism 128, e.g., a changeable wear plate mechanism, that is connected detachably against one side 208 of the reservoir 104. The connection mechanism 128 comprises openings, which are aligned with the openings of the reservoir 104, and connection means to connect the previously mentioned swing mechanism 130, which is arranged to the cylinder end 126 of each swing pipe 116, to the connection mechanism 128.

[0036] Each cylinder end 126, i.e., the swing pipe 116, comprises the swing mechanism 130, which is a part of the swing pipe mechanism 114. The swing mechanism 130 is configured to swing S the cylinder end 126, which is towards the pumping cylinders 112 and away from the connection pipe 118, between the open and closed positions OP, CL while the pipe end 222 of the swing pipe 116, which is away from the pumping cylinders 112, is connected to the connection pipe 118 and rotates R by means of the bearing mechanism 120 due tu the movements of swinged cylinder end 126.

[0037] Each cylinder end 126 further comprises the previously mentioned sealing ring 332, e.g., a changeable ring-shaped seal, which is a part of the swing pipe mechanism 114. The sealing ring 332 is configured to slide along the connection mechanism 128 on the inner surface of the reservoir 104, when the swing pipe 116 swings S between the open and closed position OP, CL and to seal the connection between the swing pipe 116 and the connection mechanism 128 when the swing pipe 116 is in the closed position CL so that the pumping cylinder 112 is able to unload the substance through the connected swing pipe 116.

[0038] The pump system 100 further comprises a pump controller 134 that is configured to control operating parts of the pump system 100, e.g., at least parts 112, 114, 116, 136, 140, 142 to operate the pump system 100, e.g., to synchronize the loading and unloading steps of the pumping cylinders 112 by means of the swing pipe mechanism 114, i.e., the swing pipes and swing mechanisms 116, 130, so that any unwanted changes do not exist in a flow of the substance from the pumping cylinders 112.

[0039] The pump controller 134 comprises a processor configured to carry out operator-intiated instructions, computer program (application, software)-initiated instructions, or both. The processor 134 is further configured to process information to run computer programs CM. The processor 134 comprises at least one processor, e.g., one, two, three, four, or more processors.The pump controller 134 further comprises a memory, which is not presented in the figures, that is configured to store and to maintain information. The information comprises, e.g., instructions, computer programs CM, and information files. The memory comprises at least one memory, e.g., one, two, three, four, or more memories.

[0040] The processor together with the memory, which stores a computer program CM to operate the pump system 100, are configured to control the pump system 100 and its parts 112, 114, 116, 136, 140, 142 so that the pump system 100 carries out the operations that have been explained previously and later on.

[0041] The pump system 100 further comprises a pumping actuator 136, e.g., a hydraulic actuator, that is controlled by the pump controller 134. The pumping actuator 136 is configured to cause each pumping cylinder 112 to carry out a suction step (movement) U by means of its piston 338 to load the substance in the pumping cylinder 112 and to cause each pumping cylinder 112 to carry out a pressure movement P by means of its piston 338 to unload the substance from the pumping cylinder 112 on the grounds of control commands from the pump controller 134. The pump system 100 further comprises a swing actuator 140, e.g., hydraulic, pneumatic, mechanical, electromechanical, or eletric actuator, that is controlled by the pump controller 134. The swing actuator 140 is configured to cause each swing pipe 116 to carry out a closing swing S by means of its swing mechanism 130 to move the swing pipe 116 from the open position OP to the closed position CL for loading the pumping cylinder 112 and to cause each swing pipe 116 to carry out an opening swing S by means of its swing mechanism 130 to move the swing pipe 116 from the closed position CL to the open position OP for unloading the pumping cylinder 112 on the grounds of control commands from the pump controller 134.

[0042] The pump system 100 further comprises a measurement system 142 that is controlled by the pump controller 134. The measurement system 142 is configured to measure parameters PP, PR, SP so that the pump system 100 can carry out the operations explained previously and later on.

[0043] The measurement system 142 comprises at least one position sensor 244, e.g., one, two, three, four, or more position sensors, for each pumping cylinder 112. Each position sensor 244 comprises a linear sensor or a pressure sensor configured to measure a position PP of a piston 338 in a pumping cylinder 112. The lin-ear sensor comprises, e.g., a magnetostrictive linear sensor, inductive linear variable differential transformer (LVDT), or resistive linear potentiometer. The pressure sensor comprises at least one pressure sensor, e.g., one, two, three, four, or more pressure sensors mounted on each pumping cylinder 112. The position PP of the piston 338 is measured by the at least one position sensor 244 during a piston (cylinder) stroke, i.e., during a pressure movement P, in the pumping cylinder 112.

[0044] The measurement system 142 may further comprise at least one pressure sensor 246, e.g., one, two, three, four, or more pressure sensors for each pumping cylinder 112, if a pressure PR is measured and the positions PP of the pistons 338 are measured by other sensor type. Each pressure sensor 246 is configured to measure the pressure PR from a cylinder chamber 248 of the pumping cylinder 112. The pressure PR is measured by the at least one pressure sensor 246 during the piston stroke in the pumping cylinder 112, e.g., from a cap end of the pumping cylinder 112, a rod end of the pumping cylinder 112, or both.

[0045] The measurement system 142 may further comprise at least one position sensor 250, e.g., one, two, three, four, or more position sensors, for each swing pipe 116. Each position sensor 250 comprises a magnetic or inductive position sensor. Each position sensor 250 is configured to measure a position PS of the swing pipe 116 during the operation of the pump system 100.

[0046] The pump controller 134 is further configured to receive a measurement data relating to at least the position PP of the piston 338 in each pumping cylinder 112 from the at least one position sensor 244. The at least one position sensor 244 transmits the measurement data continuously or at short intervals to the pump controller 134. The pump controller 134 can determine a current substance’s flow rate (volumetric flow rate) outside the pump system 100 based on the measurement data regardless of the sensor type.

[0047] If the piston position data is measured by the pressure sensor, the pump controller 134 can also determine the pressure PR in each pumping cylinder 112 based on the measurement data from the the at least one position sensor 244.

[0048] If the pressure PR is measured and the positions PP are measured by other sensor type than the pressure sensor, the pump controller 134 is further configured to receive a measurement data relating to the pressure PR in each cylinder chamber 248 from the at least one pressure sensor 246. The at least one pressure sensor246 transmits the measurement data continuously or at short intervals to the pump controller 134. The pump controller 134 can then determine the current pressure PR in each cylinder chamber 248 based on the measurement data.

[0049] If the positions PS of the swing pipes 116 are measured, the pump controller 134 is further configured to receive a measurement data relating to the position PS of each swing pipe 116 from the at least one position sensor 250. The at least one position sensor 250 transmits the measurement data continuously or at short intervals to the pump controller 134. The pump controller 134 can then determine the current position PS of each swing pipe 116, e.g., whether the swing pipe 116 is in the closed position CL such that the substance can flow from the pumping cylinder 112 to the swing pipe 112 or in the open position OP such that the substance can be loaded into the opened pumping cylinder 112, based on the measurement data.

[0050] The pump controller 134 is further configured to use at least the determined current substance’s flow rate, e.g., the determined substance’s flow rate alone, the determined substance’s flow rate and pressures PR when possible, the determined substance’s flow rate and positions PS when possible, or the determined substance’s flow rate, pressures PR, and positions PS when possible, to control the loading and unloading steps of the pumping cylinders 112 by means of the swing pipe mechanism 114 for preventing any unwanted changes in the substance flow from the pumping cylinders 112.

[0051] The pump controller 134 controls and optimizes a pumping speed of the substance by synchronizing the operation of the pumping cylinders 112 and the swing pipe mechanism 114. The pump controller 134 carries out the control and optimization based on the received measurement data and at least one of substance’s target flow rate, limit values of substance’s flow rate, and pressure values predetermined in view of a quality of the substance to be pumped.

[0052] The pump controller 134 carries out the control and optimization to keep (maintain) the current substance flow rate at a predetermined target value exactly, at the predetermined target value substantially, or within predetermined limits (limit values), i.e. , between lower and upper thresholds, during each change of a pushing cylinder 112. The control and optimization carried out by the pump controller 134 prevents unwanted changes in the substance flow (outflow), i.e., the substance flow rate, outside the pump system 100 and thus a decreased quality of the sprayed substance when additional substances are added to the sprayed substance.Fig. 3a-3e present how the loading and unloading steps of the pumping cylinders 112 are synchronized by means of the pump controller 134 and actuators 136, 140, which operates the pumping cylinders 112 and the swing pipe mechanism 114 in the previously explained pump system 100. The synchronization is based on the measurement data received from the measurement system 142,

[0053] The operation of the pump system 100 is explained by means of two pumping cylinders 112, but the pump system 100 may comprise more pumping cylinders 112 as long as at least two of the pumping cylinders 112 are synchronized correspondingly as in the presented example of two, left and right, pumping cylinder 112. At first, a left swing pipe 116 is in the open position OP and a left piston 338 makes the suction movement U by means of the pumping actuator 136 away from the left swing pipe 116 to load the left pumping cylinder 112 with the substance from the reservoir 104. At the same time, a right swing pipe 116 is in the closed position CL and a right piston 338 makes the pressure movement P by means of the pumping actuator 136 towards the right swing pipe 116 to unload the substance from the right pumping cylinder 112 outside the pump system 100 through the closed right swing pipe 116 and the connection pipe 118 as presented in fig.

[0054] 3a.

[0055] Next, the left swing pipe 116 starts to swing S from the open position OP towards the closed position CL to close pumping cylinder 112 by means of the swing mechanism 130 and the swing actuator 140 while the left piston 130 is stopped by the pumping actuator 136 when the loading step of the left pumping cylinder 112 has been completed. At the same time, the right piston 338 continues the pressure movement P to unload the substance from the closed right pumping cylinder 112 while the right swing pipe 116 is still in the closed position CL as presented in fig.

[0056] 3b.

[0057] Next, the left swing pipe 116 completes the swing S to the closed position CL, whereupon the left pumping cylinder 112 is closed and the left piston 338 then starts to make the pressure movement P by means of the pumping actuator 136 towards the left swing pipe 116 to unload the substance from the left pumping cylinder 112 outside the pump system 100 through the closed left swing pipe 116 and the connection pipe 118. At the same time, the right piston 338 continues the pressure movement P to complete the unloading step for unloading the rest of the substance from the right pumping cylinder 112 while the right swing pipe 116 is still in the closed position CL, whereupon both closed pumping cyliders 112, i.e.,the left and right pumping cylinders 112, push the substance simultaneously for a moment as presented in fig. 3c.

[0058] The simultaneous loading step of both pumping cylinders 112 prevents a decrease of the substance flow when the left pumping cylinder 112 has started to operate as a pushing cylinder before the right pumping cylinder 112, which has been closed longer than the left pumping cylinder 112, has completed its unloading step and changes its role from the pushing cylinder as a loading cylinder.

[0059] Next, the left piston 338 continues the pressure movement P to unload the substance from the closed left pumping cylinder 112 while the left swing pipe 116 is still in the closed position CL. At the same time, the right swing pipe 116 starts to swing S from the closed position CL towards the open position OP to open pumping cylinder 112 by means of the swing mechanism 130 and the swing actuator 140 while the right piston 130 is stopped by the pumping actuator 136 when the unloading step of the right pumping cylinder 112 has been completed as presented in fig. 3d.

[0060] Finally, the loading and unloading steps of the pumping cylinders 112 have interchanged with respect to fig. 3a. The left piston 338 still continues the pressure movement P to unload the substance from the closed left pumping cylinder 112 while the left swing pipe 116 is still in the closed position CL. At the same time, the right swing pipe 116 completes the swing S to the open position OP, whereupon the right pumping cylinder 112 is open and the right piston 338 then starts to make the suction movement U by means of the pumping actuator 136 away from the right swing pipe 116 to reload the open right pumping cylinder 112 with the substance from the reservoir 104 as presented in fig. 3e.

[0061] The synchronized operation of the pump system 100, i.e. , the loading and unloading steps of the pumping cylinders 112, continues in a similar manner until the pump controller 134 interrupts the operation.

[0062] The invention and its several advantages have been now explained above with reference to the above exemplary embodiments. It is clear that the invention is not only restricted to these embodiments, but it comprises all possible embodiments within the scope of the following claims.

Claims

Claims1. A pump system (100) for pumping a substance comprisingpumping cylinders (112) anda swing pipe mechanism (114),wherein each pumping cylinder (112) is configured to load the substance, when said pumping cylinder is open to operate as a loading cylinder, and to push the substance from the pumping cylinder (112), when said pumping cylinder is closed to operate as a pushing cylinder,wherein the swing pipe mechanism is configured to open one of the pumping cylinders for loading the substance to said pumping cylinder (112) and to close another of the pumping cylinders for directing the substance from said pumping cylinder (112) outside the pump system, andthe pump system further comprises a pump controller (134) for synchronizing the loading and the pushing of the substance of the pumping cylinders by means of the swing pipe mechanism, which comprises a swing pipe (116) for each pumping cylinder (112), so that the swing pipe mechanism is further configured to keep the pumping cylinders closed by means of the swing pipes (116) to push the substance from the pumping cylinders simultaneously for a moment for preventing an unwanted change in a substance flow outside the pump system during a change of the pushing cylinder.

2. The pump system according to the previous claim, wherein the swing pipe mechanism is configured to open a pumping cylinder (112), which has been closed longer than another pumping cylinder (112), by means of a swing pipe (116) to reload said pumping cylinder when both pumping cylinders (112) have been closed simultaneously and said pumping cylinder has completed an unloading of the substance.

3. The pump system according to claim 2, wherein said another pumping cylinder is configured to complete the unloading of the substance during the reloading of said open pumping cylinder.

4. The pump system according to any of the previous claims, wherein the swing pipe mechanism is configured to close an open pumping cylinder (112), which has completed a loading of the substance, by means of a swing pipe (116), to push the substance from said pumping cylinder during an unloading of the substance from another pumping cylinder (112), which has been closed by means of a swing pipe5. The pump system according to claim 4, wherein the swing pipe mechanism is configured to complete a closing of said pumping cylinder (112) by means of said swing pipe during the unloading of said another closed pumping cylinder.

6. The pump system according to any of the previous claims, which further comprises a connection pipe (118) configured to direct the substance from both swing pipes (116) to a hose of a spraying machine.

7. The pump system according to any of the previous claims, which further comprises a reservoir (104) configured to receive the substance to allow the pump system to load the substance to the pumping cylinders and to push the substance outside the pump system.

8. The pump system according to any of the previous claims, which further comprises a connection mechanism (128) configured to connect each swing pipe (116) to a reservoir (104) so that a cylinder end (126) of the swing pipe is configured to swing between open and closed positions (OP, CL) with respect to the reservoir.

9. The pump system according to claim 8, wherein the cylinder end of the swing pipe comprises a swing mechanism (130) configured to swing the swing pipe between the open and closed positions and a sealing ring (332) configured to seal a connection between the swing pipe and the connection mechanism when the swing pipe is in a closed position (CL).

10. The pump system according to any of the previous claims, which further comprises an end mechanism (120) configured to connect each swing pipe (116) to a reservoir (104) so that a cylinder end (126) of the swing pipe, which is towards the pumping cylinders, is configured to swing between open and closed positions (OP, CL) while a pipe end (222) of the swing pipe (116), which is away from the pumping cylinders, is connected to the reservoir.

11. The pump system according to claim 10, wherein the pipe end of each swing pipe (116) comprises a bearing mechanism (124) configured to rotate the pipe end of the swing pipe with respect to the reservoir to allow the cylinder end of the swing pipe to swing between the open and closed positions.

12. The pump system according to any of the previous claims, which further comprises a pump controller (134) configured to cause operations of the pumping cylinders and the swing pipe mechanism.

13. The pump system according to claim 12, which further comprises a measurement system (142, 244, 246, 250) configured to measure a position (PP) of a piston (338) in each pumping cylinder, wherein the pump controller is configured to control the operations of the pumping cylinders and the swing pipe mechanism based on the position of the piston of each pumping cylinder for preventing the unwanted change in the substance flow.

14. The pump system according to claim 13, wherein the measurement system is further configured to measure a position (PS) of each swing pipe (116), wherein the pump controller is further configured to control the operations of the pumping cylinders and the swing pipe mechanism based on the position of the piston of each pumping cylinder and the position of each swing pipe.

15. The pump system according to claim 13, wherein the measurement system is further configured to measure a pressure (PR) from each pumping cylinder, wherein the pump controller is further configured to control the operations of the pumping cylinders and the swing pipe mechanism based on the position of the piston and the pressure in each pumping cylinder.

16. A pumping method for pumping a substance by means of the pump system (100) according to any of the previous claims, comprising at least following steps ofopening, by the swing pipe mechanism (114), one of the pumping cylinders (112) and closing, by the swing pipe mechanism, another of the pumping cylinders,loading, by said opened pumping cylinder (112) operating as a loading cylinder, the substance,pushing, by each closed pumping cylinder (112) operating as a pushing cylinder, the substance from said pumping cylinder (112), anddirecting, by the swing pipe mechanism, the substance from each closed pumping cylinder (112) outside the pump system,wherein the pump controller (134) synchronizes the swing pipe mechanism to keep the pumping cylinders (112) closed by means of the swing pipes (116) to push the substance from the pumping cylinders simultaneously for a moment for preventing an unwanted change in a substance flow outside the pump system during a change of the pushing cylinder.

17. A computer program (CM) comprising instructions, which, when the computer program is executed by a pump controller (134) that comprises a processor, causethe pump system (100) to carry out at least the steps of the pumping method according to claim 16.

18. A tangible, non-volatile computer readable medium comprising the computer program (CM) according to claim 17.

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