Fluid return device for double-acting pneumatic cylinder and method for operating the cylinder

Abstract

The present invention relates to a fluid return device (1) for a double-acting cylinder (20, 200). In order to achieve a reduction in fluid consumption during operation of the double-acting cylinder (20, 200), the fluid return device (1) comprises: a first fluid channel (7) for creating fluid communication between a first fluid connection (51) and a first cylinder chamber (21) away from a piston rod; and a quick discharge valve (3) comprising an inlet (4) for communicating with a second fluid connection (52), an outlet (5) for communicating with a second cylinder chamber (22) on the piston rod side, and a discharge port (6) connected to the first fluid channel (7) through a second fluid channel (8). The fluid return device (1) also comprises a check fitting (9) and an auxiliary outlet device (10) in the second fluid channel (8) for preventing fluid from flowing from the first fluid channel (7) to the quick discharge valve (3). The invention also relates to a double-acting cylinder (200) comprising an integrated fluid return device (1), a device for operating a double-acting cylinder (20, 200) and a method for operating a double-acting cylinder (20, 200).

Description

Technical Field

[0001] The present invention relates to a fluid return device for a double-acting cylinder, a device for operating a double-acting cylinder and a method for operating a double-acting cylinder. Background Art

[0002] In a double-acting cylinder, the internal space of the cylinder is divided by the piston into a first cylinder chamber, which is away from the piston rod, and a second cylinder chamber, which is located on the piston rod side. The piston rod is attached to the piston and extends outward through the second cylinder chamber. The cylinder - or more precisely the piston rod - is extended by charging the first cylinder chamber with compressed gas. As a result, the volume of the first cylinder chamber increases, while the volume of the second cylinder chamber decreases, during which the piston moves to the second cylinder chamber side.

[0003] For example, in DE 2648358 A1 and DE 3804081 A1, it has been suggested that a quick discharge valve be connected to the cylinder chamber of a pneumatic cylinder so that when its volume is reduced, the fluid can escape from the corresponding cylinder chamber more quickly. In this case, the gas in the relevant cylinder chamber is discharged outwardly into the surrounding environment.

[0004] The efficiency of pneumatic cylinders can be increased by means of energy-saving circuits. Such energy-saving circuits are known, for example, from "Energetische Untersuchung und Verbesserung der Antriebstechnik pneumatischer Handhabungssysteme [Energy Investigation and Improvement of Drive Technology for Pneumatic Handling Systems]", by Jan Hepke, 1st edition, 2017, ISBN 978-3-8440-5254-1. However, the known solutions have the disadvantage that they require a large number of components or additional control functions. Therefore, in particular the retrofitting of existing installations is only possible with considerable effort.

[0005] In addition, by using known energy-saving circuits, the retraction force or extension force of the double-acting pneumatic cylinder is reduced in some cases. In addition, depending on the operating mode, the movement speed of the piston can be reduced at least in one of these movement directions. Summary of the invention

[0006] It is an object of the present invention to provide an apparatus and a method whereby the fluid consumption during operation of a double-acting cylinder is reduced.

[0007] This object is achieved by a fluid return device for a double-acting cylinder having the features of claim 1 .

[0008] The fluid return device of the double-acting cylinder comprises: a first fluid supply device for supplying fluid to a first cylinder chamber of the cylinder away from the piston rod and a second fluid supply device for supplying fluid to a second cylinder chamber on the piston rod side of the cylinder;

[0009] A first fluid passage, the first fluid passage establishing fluid communication between the first fluid connection and the first cylinder chamber, a quick discharge valve, the quick discharge valve comprising

[0010] an inlet in communication with the second fluid connection,

[0011] an outlet communicating with a second cylinder chamber on the piston rod side of the cylinder, and

[0012] an outlet connected to the first fluid passage through a second fluid passage, and

[0013] A check valve is provided in the second fluid passage to prevent fluid from flowing from the first fluid passage to the quick discharge valve.

[0014] For example, the first fluid channel may be configured as a line, a pipe, a hose, or a channel in a substrate.

[0015] If the fluid return device is connected to a double-acting cylinder, the first cylinder chamber can be supplied with fluid via the first fluid channel in order to extend the cylinder (more precisely: the piston rod of the double-acting cylinder). In this case, the fluid flows from the first fluid connection through the first fluid channel into the first cylinder chamber. Therefore, the first fluid connection can also serve as the first fluid supply device.

[0016] When the volume of the second cylinder chamber decreases during the extension of the cylinder, the fluid flows from the second cylinder chamber to the outlet of the quick discharge valve and enters the quick discharge valve. The quick discharge valve prevents the fluid from entering the inlet of the quick discharge valve from the outlet of the quick discharge valve and flowing out from the inlet. On the contrary, it enables the fluid to flow out of the second cylinder chamber in this state, further enter the second fluid channel through the discharge port of the quick discharge valve.

[0017] The quick discharge valve thus acts similarly to a non-return valve with respect to the fluid connection between its inlet (and the associated second fluid connection) and its outlet (and the associated second cylinder chamber).

[0018] As described above, a check valve is provided in the second fluid channel. If the fluid pressure in the second fluid channel is higher than the fluid pressure in the first fluid channel on the discharge port side (upstream side) of the quick discharge valve, the fluid flows from the discharge port of the quick discharge valve through the second fluid channel and the check fitting into the first fluid channel and eventually into the first cylinder chamber. Therefore, during the extension of the cylinder, at least a portion of the fluid moved out of the second cylinder chamber by the piston of the double-acting cylinder enters the first fluid channel and eventually flows back to the first cylinder chamber. In other words, the quick discharge valve and the second fluid channel are used to allow the fluid to flow back from the second cylinder chamber to the first cylinder chamber.

[0019] A double-acting cylinder is a double-acting cylinder with a single-sided piston rod. The internal space of the cylinder is divided by the piston into a first cylinder chamber away from the piston rod and a second cylinder chamber on the piston rod side. The piston rod extends through the second cylinder chamber on the piston rod side of the cylinder. Therefore, the second effective cross-sectional area of ​​the piston on the second cylinder chamber side is smaller than the first effective cross-sectional area of ​​the piston on the first cylinder chamber side. Therefore, when a fluid (such as compressed gas) is supplied to the first cylinder chamber from the outside (through the first fluid connector and the first fluid channel), the fluid pressure in the second cylinder chamber may exceed the fluid pressure in the first cylinder chamber. Due to this pressure difference, the fluid can flow back from the second cylinder chamber to the first cylinder chamber in the described manner, and has an energy advantage.

[0020] Due to the return flow of the fluid, the first fluid connection needs to be additionally supplied with less fluid in order to extend the double-acting cylinder. For example, 24% of compressed gas is saved during the entire cycle (contraction and extension) of the cylinder with the fluid return device. This greatly improves the efficiency of the connected cylinder, making the operation of the double-acting cylinder more economical, more energy-saving and more environmentally friendly. Finally, in particular, carbon dioxide emissions can be reduced.

[0021] When the fluid return device is connected to the double-acting cylinder, on the other hand, the second cylinder chamber can be supplied with fluid via the quick discharge valve. To this end, the fluid flows from the second fluid connection into the inlet of the quick discharge valve and further flows into the second cylinder chamber via the outlet of the quick discharge valve. Therefore, the second fluid connection serves as a second fluid supply device during contraction. The piston is moved so that the volume of the second cylinder chamber increases and the volume of the first cylinder chamber decreases. The fluid in the first cylinder chamber can escape through the first fluid channel and further via the first fluid connection. Alternatively, or additionally, during contraction of the cylinder (or its piston rod), the fluid can escape from the first cylinder chamber in different ways.

[0022] During retraction, the cylinder can be operated as conventionally without a fluid return device connected.

[0023] The basic advantage of the quick discharge valve is that it safely and reliably closes the inlet, allowing the fluid to flow back, thereby ensuring that the fluid flows back from its outlet to its discharge port. On the other hand, when the fluid under increased pressure is supplied from the second fluid connection at its inlet, it opens its inlet and closes its discharge port. Therefore, the fluid can be reliably supplied to the second cylinder chamber to contract the cylinder. At the same time, in this state, no fluid supplied by the second fluid connection enters the second fluid channel in an undesirable manner because the discharge port is closed during contraction.

[0024] The advantage of the fluid return device is its simple construction. It is cost-effective and space-saving. In addition, it can be integrated simply, cost-effectively and quickly. It is suitable for any double-acting cylinder with a one-sided piston rod.

[0025] The fluid return device according to the invention is further characterized in that the extension force during extension of the cylinder using the fluid return device remains at least substantially the same. Preferably, the extension force of the double-acting cylinder using the fluid return device is reduced by less than 10%, particularly preferably by less than 5%, and very preferably by less than 2%. This includes in particular the fact that the extension force of the double-acting cylinder using the fluid return device is equal to or even greater than the extension force of the double-acting cylinder without the fluid return device.

[0026] Alternatively or additionally, the fluid return device of the invention is characterized in that during the retraction of the cylinder using the fluid return device, the retraction force remains at least substantially the same. Preferably, the retraction force of the double-acting cylinder using the fluid return device decreases by less than 10%, particularly preferably by less than 5%, and most preferably by less than 2%.

[0027] In this sense, as a comparison, operation of the same cylinder without a fluid return device under the same conditions was applied, wherein the first cylinder chamber was directly connected to the first fluid connection in a conventional manner and the second cylinder chamber was directly connected to the second fluid connection.

[0028] Therefore, the fluid return device can be safely used in known devices without having to worry about a significant reduction in its performance.For this reason, the fluid return device is simply connected between the first fluid connection and the first cylinder chamber and the second fluid connection and the second cylinder chamber in the described manner.

[0029] The fluid is preferably a gas. In particular, the first fluid connection can be used as a first compressed gas supply. Alternatively, or in addition, the second fluid connection can be used as a second compressed gas supply. Gas is easily and cheaply supplied. It can be provided simply, economically, quickly and in large quantities in a known manner.

[0030] In another advantageous embodiment, the non-return fitting comprises a non-return valve. Particularly preferably, the non-return fitting is a non-return valve. This contributes to the establishment of a simple, compact and economical structure.

[0031] In a further development of the invention, the inlet, outlet and / or discharge opening of the quick discharge valve are respectively configured as fluid connections, particularly preferably compressed gas connections, most preferably compressed gas connectors. This allows a simple and safe connection of the quick discharge valve, optionally a detachable connection.

[0032] Preferably, the fluid return device comprises a fluid connection for connecting the first cylinder chamber, the second cylinder chamber, the first fluid connection and / or the second fluid connection, particularly preferably a compressed gas connection, most preferably a compressed gas connection. This ensures easy handling and installation of the fluid return device. In particular, it can thus be retrofitted particularly quickly and easily.

[0033] In a further development of the present invention, the flow cross section of the second fluid channel is roughly the same as the flow cross section of the first fluid channel. In a particularly preferred embodiment of the present invention, the flow cross section of the second fluid channel is at most 30% larger or smaller than the flow cross section of the first fluid channel, particularly preferably 20%, and completely preferably 10%. Therefore, the energy benefit of the fluid flowing back from the second cylinder chamber to the first fluid channel and backflowing to the first cylinder chamber is particularly large. When the flow cross section of the second fluid channel becomes larger, the volume of the second fluid channel also increases, and the pressure inside it decreases. This has an adverse effect on the energy gain of the fluid return. When the flow cross section of the second fluid channel becomes smaller, this tends to lead to a higher pressure inside it, but the volume of the fluid flowing back to the first cylinder chamber is reduced, or even insufficient. Therefore, it is advantageous that the flow cross sections of the second fluid channel and the first fluid channel are roughly the same.

[0034] Alternatively or additionally, the flow cross section of the second fluid channel is

[0035] the flow cross section of the first fluid connection,

[0036] the flow cross section of the second fluid connection,

[0037] The flow cross section of the fluid passage between the outlet of the quick discharge valve and the second cylinder chamber and / or

[0038] the flow cross section of the fluid passage between the first fluid channel and the first cylinder chamber (if known),

[0039] At most 30% larger or smaller, particularly preferably at most 20% smaller, most preferably at most 10% larger or smaller. Such a dimensioning of the second fluid channel ensures a particularly high energy efficiency of the return flow.

[0040] The fluid return means comprises an auxiliary outlet means. The auxiliary outlet means is adapted to counteract the remaining excess pressure in the second cylinder chamber during the extension of the cylinder. For example, it can discharge the fluid into the surrounding environment or into a collection tank.

[0041] Preferably, the auxiliary outlet means is adapted such that when the non-return fitting is closed, while the cylinder is extended, fluid can flow from at least the second cylinder chamber, out of the fluid return means.

[0042] As previously described, the check fitting prevents fluid from flowing from the first fluid channel into the quick discharge valve via the second fluid channel. As a result, no fluid can flow out of the first fluid channel through the auxiliary outlet device. For example, if the fluid pressure in the first fluid channel is the same, the check fitting, which performs as a check valve, can be closed during cylinder extension. At the same time, during cylinder extension, the quick discharge valve prevents the fluid flowing into the outlet from flowing out through the inlet. As a result, a residual excess pressure may remain in the second cylinder chamber compared to a reference pressure (e.g., ambient pressure). The residual excess pressure can slow down or even hinder the full extension of the cylinder. As described above, the auxiliary outlet device is used to offset the residual excess pressure in the second cylinder chamber during cylinder extension (i.e., reduce or even prevent such residual excess pressure).

[0043] Preferably, the auxiliary outlet device is connected in parallel with the non-return fitting of the outlet of the quick discharge valve. It can be connected to the second fluid channel between the outlet and the non-return fitting in particular. This allows for simple and economical integration.

[0044] For example, the auxiliary outlet device may include an outlet opening, a throttle and / or a controllable valve.

[0045] In a simple case, the auxiliary outlet device is, for example, an outlet opening whose flow cross section is substantially smaller than the flow cross section of the second fluid channel. Preferably, the flow cross section of the outlet opening is at most 10% of the flow cross section of the second fluid channel, most preferably at most 3%, particularly preferably at most 1%.

[0046] If the pressure difference between the fluid pressure in the first fluid channel and the fluid pressure at the discharge port of the quick discharge valve is large, for example, halfway through the extension of the cylinder, the fluid flowing out of the second cylinder chamber is allowed to flow through the non-return fitting and flow into the first fluid channel mainly through the second fluid channel due to the larger flow diameter. However, due to the smaller flow diameter of the outlet opening, only a small part of the fluid discharged from the second cylinder chamber is discharged through the outlet opening. If the pressure difference disappears and the non-return fitting closes during the period when the piston is close to the maximum extension position, a limited volume flow of fluid will still escape from the second cylinder chamber and be discharged outwardly through the outlet opening until the residual excess pressure disappears. The residual excess pressure is thus reduced to ambient pressure in a controlled manner and the cylinder can be fully extended at least substantially unhindered.

[0047] Preferably, the auxiliary outlet device limits the outlet volume flow rate of the fluid flowing out of the auxiliary outlet device. For example, this can be achieved by limiting the area of ​​the outlet opening. Therefore, the outlet loss of the fluid is reduced.

[0048] Alternatively or additionally, the auxiliary outlet device comprises an outlet mechanism adapted to close the fluid opening to the surroundings when the fluid pressure in the first fluid channel is at least a specified amount greater than the fluid pressure at the outlet of the quick outlet valve, and to open the fluid opening in other cases. The specified amount may be an absolute pressure difference and / or a pressure ratio. In particular, the specified amount of the pressure difference may be zero. Thus, during extension of the cylinder, there is hardly any fluid loss as long as the fluid flows back. However, this solution is more complicated than the small outlet opening described above.

[0049] Particularly preferably, the auxiliary outlet device is configured integrally with the quick discharge valve, in particular with the discharge outlet, with the second fluid channel and / or with the non-return fitting. This saves installation space, simplifies production and reduces costs. However, the auxiliary outlet device can also consist of one or more separate components.

[0050] In a preferred embodiment of the invention, the fluid return device is configured as a separate unit for connection to a double-acting cylinder. The fluid return device can therefore be produced particularly easily. Furthermore, existing devices can be retrofitted simply, economically, quickly and without problems without having to replace the cylinder or the cylinder's control valve yourself.

[0051] Another aspect of the present invention relates to the combination of a fluid return device and a double-acting cylinder.

[0052] In particular, the present invention also relates to a double-acting cylinder comprising a fluid return device according to one of the aforementioned embodiments, wherein a first fluid channel is fluidically connected to a first cylinder chamber of the cylinder away from the piston rod, and wherein an outlet of the quick discharge valve is fluidically connected to a second cylinder chamber on the piston rod side of the cylinder.

[0053] A first effective cross-sectional area of ​​the piston far from the piston rod (on the first cylinder chamber side) is larger than a second effective cross-sectional area of ​​the piston on the piston rod side (on the second cylinder chamber side).

[0054] In other words, the second effective cross-sectional area is smaller than the first effective cross-sectional area. Preferably, the second effective cross-sectional area is 40% to 95%, particularly preferably 70% to 90%, particularly preferably 80% to 90% of the first effective cross-sectional area. Thus, during contraction, on the one hand, a sufficiently high fluid pressure is ensured in the second cylinder chamber for the fluid to flow back, and on the other hand, the contraction force is still sufficiently high compared to the extension force.

[0055] Preferably, the double-acting cylinder is a double-acting cylinder with exactly one single-sided piston rod. However, it is also possible that several piston rods, i.e. at least two piston rods, are attached to the piston. For example, two piston rods may be attached to the piston, which extend outwardly through the first cylinder chamber parallel to each other. A plurality of double-acting cylinders may also be provided.

[0056] In a further development of the invention, the fluid return device and the cylinder are arranged together in the housing and / or are formed together in the base body. The system consisting of the fluid return device and the double-acting cylinder is thus particularly compact and economical. Since there is no intermediate connection, in particular a detachable intermediate connection, possible sources of malfunctions are avoided. In particular, the fluid return device can be integrated in the double-acting cylinder.

[0057] In another preferred embodiment of the invention, the fluid return device is configured as a separate unit. The double-acting cylinder and the fluid return device can have a coupling device for detachably connecting the double-acting cylinder and the actual fluid return device. Thus, the two elements can be quickly and easily separated from each other or connected to each other, maintained and, if necessary, quickly replaced.

[0058] The fluid return device and / or the cylinder are preferably designed so that the fluid pressure or the operating pressure is at least 0.15 MPa, particularly preferably in the range of 0.3 to 1.6 MPa, for example 0.6 MPa.

[0059] According to another aspect, the invention also comprises a device for operating a double-acting cylinder, a fluid return device according to one of the preceding embodiments, and a control valve having a fluid inlet and at least one fluid outlet, the control valve being able to adopt at least two states. In a first state, the control valve connects the fluid inlet to a first fluid channel of the fluid return device, and in a second state, the control valve connects the fluid inlet to an inlet of a rapid discharge valve of the fluid return device and connects the first fluid channel of the fluid return device to the at least one fluid outlet.

[0060] The fluid inlet is adapted to communicate with a fluid pressure source. At least one fluid outlet is used to provide an outlet for fluid to flow out of the device.

[0061] In the first state, the inlet of the quick discharge valve is not connected to the fluid inlet. Therefore, in the first state, no fluid is supplied from the fluid inlet to the quick discharge valve and the second cylinder chamber. In the second state, the first fluid channel is not connected to the fluid inlet.

[0062] In a further development of the device, the fluid inlet of the control valve is connected to a fluid pressure source. Therefore, the fluid inlet of the control valve is supplied with fluid at a higher pressure. Particularly preferably, the fluid pressure source provides compressed gas. The fluid pressure provided by the fluid pressure source is preferably at least 0.15 MPa, particularly preferably in the range of 0.3 to 1.6 MPa, for example 0.6 MPa.

[0063] Alternatively or additionally, a muffler is connected to at least one fluid outlet of the control valve. Thus, noise of the fluid (eg compressed gas) from the at least one fluid outlet is suppressed.

[0064] In particular, the device may comprise the silencer.

[0065] Particularly preferably, the control valve is a 4 / 3-way valve. Particularly preferably, in an intermediate position between the first state and the second state, the 4 / 3-way valve is closed.

[0066] In another particularly preferred embodiment of the present invention, the control valve is a 5 / 2-way valve. This solution is more economical. In particular, in this case, the control valve can have a second fluid outlet in addition to at least one fluid outlet.

[0067] In a further development of the invention, in the first state, the control valve also connects the inlet of the quick discharge valve to the fluid outlet of the control valve. In this case, for example, this can include at least one fluid outlet or a further fluid outlet. Thus, when the control valve is switched to the first state, a higher fluid pressure can be avoided from continuing to be applied to the inlet of the quick discharge valve. During the first state, a possible fluid flow from the inlet to the outlet of the quick discharge valve is reliably eliminated.

[0068] The control valve and the fluid return device can be arranged as an integral unit. For example, both can be accommodated in a common housing and / or formed in a common matrix. In particular, the control valve can be integrated in the fluid return device. In this case, the fluid return device including the control valve can be arranged as a separate unit for connection to the double-acting cylinder.

[0069] In another embodiment, the control valve, the fluid return device and the double-acting cylinder are arranged as an integral body. In particular, the control valve and the fluid return device can be integrated in the double-acting cylinder.

[0070] The above object is further achieved by a method for operating a double-acting cylinder having the features of patent claim 10 .

[0071] Preferably, the method uses a fluid return device according to one of the preceding embodiments.

[0072] The described embodiments and advantages for the fluid return device, the combination of a fluid return device with a double-acting cylinder, the device and the method for operating a double-acting cylinder also apply accordingly to the corresponding other objects.

[0073] The invention will be explained below with reference to exemplary embodiments and the accompanying drawings. In this case, all features described and / or depicted constitute the subject matter of the invention per se or in any combination, also independently of their combination in the claims or their back-references. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In the diagram:

[0075] Figure 1 An embodiment of a fluid return device according to the present invention is illustrated;

[0076] Figure 2 The diagram shows a device for operating a double-acting cylinder comprising Figure 1 Fluid return device and control valve;

[0077] Figure 3 The figure shows a combination of a fluid return device according to the invention and a double-acting cylinder, wherein the fluid return device is integrated in the cylinder. DETAILED DESCRIPTION

[0078] according to Figure 1 The schematically illustrated embodiment of the fluid reflux device 1 according to the present invention comprises a housing 2, a quick discharge valve 3, a first fluid channel 7, a second fluid channel 8 having a check fitting configured as a check valve 9, an auxiliary outlet device 10 and four fluid connectors 11, 12, 13, 14. In an embodiment, the four fluid connectors 11, 12, 13, 14 are configured as compressed gas connectors. The second fluid channel 8 connects the discharge port 6 fluid of the quick discharge valve 3 to the first fluid channel 7. The check valve 9 in the second fluid channel 8 prevents the fluid from flowing from the first fluid channel 7 through the second fluid channel 8 in the direction of the discharge port 6. Therefore, the check valve 9 predefines the flow direction of the fluid in the second fluid channel 8, wherein the discharge port 6 leads to the upstream end of the second fluid channel 8, and the downstream end of the second fluid channel 8 leads to the first fluid channel 7.

[0079] exist Figure 1 In the embodiment shown, the fluid return device 1 is constructed as a separate unit having a housing 2. The unit is suitable for Figure 2 It is shown connected to a double-acting cylinder 20. In this case, compressed gas is used as the fluid.

[0080] The fluid connection 12 on the first cylinder side is used to connect the double-acting cylinder 20 ( Figure 1 Not shown in the figure, such as Figure 2 The first cylinder chamber 21 of the cylinder 20 (shown) is connected to the fluid return device 1. The fluid connection 14 on the second cylinder side is used to connect the second cylinder chamber 22 of the same cylinder 20 to the fluid return device 1.

[0081] The first fluid connection 11 away from the cylinder is used to connect to the first fluid connection, through which the fluid can be supplied to the first cylinder chamber 21. The second fluid connection 13 away from the cylinder is used to connect to the second fluid connection, through which the fluid can be supplied to the second cylinder chamber 22.

[0082] The first fluid channel 7 connects the first fluid connection 11 remote from the cylinder with the first fluid connection 12 on the cylinder side in direct fluid communication.

[0083] The quick discharge valve 3 has an inlet 4 , an outlet 5 and a discharge port 6 .

[0084] The inlet 4 is in direct fluid communication with a second fluid connection 13 remote from the cylinder. Generally, a second fluid passage can be connected to the inlet 4 and can be connected accordingly when the fluid return device 1 is used.

[0085] The outlet 5 is in direct fluid communication with the second cylinder-side fluid connection 14. Generally, the second fluid passage can be connected to the second cylinder chamber 22 on the piston rod side and can be connected accordingly when the fluid return device 1 is used.

[0086] As described above, the outlet port 6 is adjacent to the second fluid channel 8 .

[0087] The quick discharge valve 3 provides a rebound function in relation to the fluid passage from the inlet 4 to the outlet 5. The fluid can (at least substantially unimpeded) flow from the inlet 4 to the outlet 5 and out of the outlet 5. On the other hand, the quick discharge valve 3 prevents the fluid from flowing out of the outlet 5 through the inlet 4. When the fluid flows into the quick discharge valve 3 through the outlet 5, it flows out of the quick discharge valve 3 through the discharge port 6.

[0088] Preferably, individual or all fluid connections 11, 12, 13, 14 function as compressed gas connections in order to enable a simple and reliable connection of the fluid return device 1. The fluid return device 1 can thus be easily removed again.

[0089] refer to Figure 2 , the operation and use of the fluid reflux device 1 are explained in more detail.

[0090] The same elements are provided with the same reference signs in different drawings, and the corresponding explanations apply equally to the different drawings.

[0091] exist Figure 2 In the embodiment, the double-acting cylinder 20 and the control valve 30 are connected to Figure 1 A fluid return device 1.

[0092] Figure 2The cylinder 20 shown includes a double-acting pneumatic cylinder with a single-sided piston rod 24. Compressed gas is used as a fluid to move the piston. The internal space of the cylinder 20 is divided into a first cylinder chamber 21 and a second cylinder chamber 22 by a piston 23. The piston 23 is accommodated in the internal space of the cylinder 20 so that it can move in the longitudinal direction of the cylinder 20. The piston rod 24 is attached to the piston 23. Exactly one piston rod 24 of the cylinder 20 extends from the piston 23 through the second cylinder chamber 22 in the longitudinal direction of the cylinder 20, and protrudes from the internal space of the cylinder 20. The piston rod 24 transmits the movement of the piston 23 to the outside. Therefore, an external object can be moved through the cylinder 20 by means of the piston rod 24.

[0093] exist Figure 2 In the embodiment, the first cylinder chamber 21 away from the piston rod is connected to the fluid connection 12 on the first cylinder side of the fluid return device 1, and the second cylinder chamber 22 on the piston rod side is connected to the fluid connection 14 on the second cylinder side of the fluid return device 1. Therefore, the first cylinder chamber 21 is directly fluidically connected to the first fluid channel 7, and the second cylinder chamber 22 is directly fluidically connected to the outlet 5 of the quick discharge valve 3.

[0094] In this embodiment, the control valve 30 is a 5 / 2-way control valve for compressed gas. The second fluid connection 32 (compressed gas connection) of the control valve 30 is connected to the first fluid connection 11 of the fluid return device 1 away from the cylinder via the first fluid passage 51. The fourth fluid connection 34 of the control valve 30 is connected to the second fluid connection 13 of the fluid return device 1 away from the cylinder via the second fluid passage 52.

[0095] Obviously, the first fluid passage 51 is particularly used as a first fluid connection for supplying fluid (more precisely, compressed gas) to the first cylinder chamber 21 of the cylinder 20 away from the piston rod. The second fluid passage 52 is particularly used as a second fluid connection for supplying fluid (more precisely, compressed gas) to the second cylinder chamber 22 on the piston rod side of the cylinder 20.

[0096] The first compressed gas connection piece of the control valve 30 serves as a fluid inlet 31 and is fluidly connected to a fluid supply source 40, which in this embodiment is configured as a compressed gas source. The third fluid connection piece of the control valve 30 serves as a first fluid outlet 33a of the control valve 30. A first muffler 41a is connected to the first fluid outlet 33a, through which the compressed gas can be discharged to the atmosphere.

[0097] The fifth fluid connection of the control valve 30 serves as a second fluid outlet 33b of the control valve 30. A second muffler 41b is connected to the second fluid outlet 33b, through which the compressed gas can be discharged to the atmosphere.

[0098] The control valve 30 can adopt two states.

[0099] exist Figure 2 In the first state shown, to extend the cylinder 20, the control valve 30 connects the fluid inlet 31 to the second compressed gas connection 32 and correspondingly to the first fluid channel 7 (via the first fluid passage 51 and the first remote compressed gas connection 11).

[0100] In the second state, not shown, in order to retract the cylinder 20, the control valve 30 connects the fluid inlet 31 to the fourth compressed gas connection 34 and, accordingly (via the second fluid passage 52 and the second compressed gas connection 13 remote from the cylinder) to the inlet 4 of the quick discharge valve 3. At the same time, in its second state, the control valve connects its second fluid connection 32 (and therefore the first fluid connection 11 remote from the cylinder via the first fluid passage 51 and the first fluid channel 7) to its first fluid outlet 33a.

[0101] During the extension of the double-acting cylinder 20, before the cylinder 20 is fully extended, when the check valve 9 is closed, a residual excess pressure may be generated in the second cylinder chamber 22. This residual excess pressure may hinder or at least slow down the full extension of the piston rod 24. Therefore, between the discharge port 6 and the check valve 9, an auxiliary outlet device 10 is connected to the second fluid channel 8. The auxiliary outlet device 10 is connected to the discharge port 6 in parallel with the check valve 9. In the exemplary embodiment, the auxiliary outlet device 10 comprises a small outlet opening. The outlet opening can be a small hole in the discharge port 6 itself or a small hole in the second fluid channel 8 between the discharge port 6 and the check valve 9. Through this outlet opening, the fluid (compressed gas) can flow out to the surrounding environment. The flow cross section of the outlet opening is substantially smaller than the flow cross section of the second fluid channel 8. Therefore, as long as the check valve 9 is open, only a negligible small part of the gas discharged from the second cylinder chamber 22 during extension flows outward from the outlet opening. However, the outlet opening is sufficient to quickly reduce the residual excess pressure in a controlled manner after closing the check valve 9. Thus, the auxiliary outlet device 10 counteracts the remaining excess pressure. Therefore, it can prevent or reduce the extension of the cylinder 20 being hindered by such remaining excess pressure.

[0102] Figure 3 Another embodiment according to the present invention is schematically illustrated, wherein Figure 1 and Figure 2 The fluid return device 1 is directly integrated in the cylinder 200. The first cylinder chamber 21, the second cylinder chamber 22, the piston 23 and the fluid return device 1 are formed together in the base body 202 of the cylinder 200. Here, the fluid return device 1 is not configured as a separate unit.

[0103] Therefore, the whole structure is more compact, easier to handle and more economical. Here, the first fluid channel 7 is directly connected to the first cylinder chamber 21. In addition, the outlet 4 of the quick discharge valve 3 is directly connected to the second cylinder chamber 22 via the third fluid channel 25. In addition, the structure and working mode correspond to Figure 1 and Figure 2 The fluid return device 1 and Figure 2 Cylinder 20 in.

[0104] By means of the proposed fluid return device 1, the compressed gas consumption of the double-acting cylinder 20, 200 is significantly reduced. At the same time, the contraction force and extension force of the cylinder 20, 200 are fully maintained. In addition, the time required for contraction is almost unchanged, and the time required for extension is only slightly increased.

[0105] Tags list:

[0106] 1 Fluid return device

[0107] 2 Housing

[0108] 3 Quick discharge valve

[0109] 4 Entrance

[0110] 5. Exit

[0111] 6. Exhaust port

[0112] 7 First fluid channel

[0113] 8 Second fluid channel

[0114] 9 Check valve

[0115] 10 Auxiliary exit devices

[0116] 11,12,13,14 Fluid connections

[0117] 20,200 cylinders

[0118] 21 First cylinder chamber

[0119] 22 Second cylinder chamber

[0120] 23 Piston

[0121] 24 Piston rod

[0122] 25 Third fluid channel

[0123] 30 Control valve

[0124] 31 Fluid inlet

[0125] 32,34 Fluid connections

[0126] 33a, 33b fluid outlet

[0127] 40 Fluid pressure source

[0128] 41a, 41b silencer

[0129] 51,52 Fluid pathways

[0130] 202 matrix

Claims

1. A fluid return device (1) for a double-acting pneumatic cylinder (20; 200), characterized in that: a first fluid connection (51) for supplying fluid to a first cylinder chamber (21) of the pneumatic cylinder (20; 200) remote from the piston rod, and a second fluid connection (52) for supplying fluid to a second cylinder chamber (22) on the piston rod side of the pneumatic cylinder (20; 200), The fluid reflux device (1) comprises: a first fluid channel (7) for establishing fluid communication between the first fluid connection member (51) and the first cylinder chamber (21); Quick discharge valve (3), including an inlet (4) for communicating with the second fluid connection member (52), an outlet (5) for communicating with the second cylinder chamber (22) on the piston rod side of the pneumatic cylinder (20; 200), and a discharge port (6) connected to the first fluid channel (7) via a second fluid channel (8), wherein the quick discharge valve (3) provides a rebound function in relation to the fluid communication from the inlet (4) to the outlet (5), wherein fluid can flow from the inlet (4) to the outlet (5) and out of the outlet (5), wherein the quick discharge valve (3) prevents fluid from flowing out of the outlet (5) through the inlet (4), The quick exhaust valve is configured such that when a fluid flows into the quick exhaust valve (3) through the outlet (5), the fluid flows out of the quick exhaust valve (3) through the exhaust port (6). wherein the fluid reflux device (1) is configured such that when the volume of the second cylinder chamber (22) decreases during the extension of the pneumatic cylinder (20; 200), the fluid flows from the second cylinder chamber (22) to the outlet (5) of the quick discharge valve (3) and enters the quick discharge valve (3), wherein the quick discharge valve (3) prevents the fluid from entering the inlet (4) of the quick discharge valve (3) from the outlet (5) of the quick discharge valve (3) and flowing out from the inlet (4), wherein the quick discharge valve (3) on the contrary enables the fluid to flow out of the second cylinder chamber (22) in this state and further enter the second fluid channel (8) through the discharge outlet (6) of the quick discharge valve (3); The fluid reflux device further comprises: a check fitting (9) in the second fluid passage (8) to prevent fluid from flowing from the first fluid passage (7) to the quick discharge valve (3); and An auxiliary outlet device (10), wherein the auxiliary outlet device (10) is connected to the discharge port (6) of the quick discharge valve (3) in parallel with the non-return fitting (9), and wherein the auxiliary outlet device (10) limits the outlet volume flow rate of the fluid flowing out of the auxiliary outlet device (10).

2. The fluid reflux device (1) according to claim 1, characterized in that: The non-return fitting (9) is configured as a non-return valve.

3. The fluid reflux device (1) according to claim 1 or 2, characterized in that: The fluid return device (1) is configured as a separate unit for connection to the double-acting pneumatic cylinder (20; 200).

4. A double-acting pneumatic cylinder (20; 200), characterized in that: include The fluid reflux device (1) according to claim 1 or 2, wherein the first fluid channel (7) is in fluid communication with a first cylinder chamber (21) of the pneumatic cylinder (20; 200) away from the piston rod, and The outlet (5) of the quick discharge valve (3) is fluidically connected to the second cylinder chamber (22) on the piston rod side of the pneumatic cylinder (20; 200).

5. The double-acting pneumatic cylinder (20; 200) according to claim 4, characterized in that: The fluid return device (1) is integrated into the pneumatic cylinder (20; 200).

6. A device for operating a double-acting pneumatic cylinder (20; 200), characterized in that include: A fluid return device (1) according to any one of the preceding claims 1 to 3 or a double-acting pneumatic cylinder (20; 200) according to any one of claims 4 or 5; and A control valve (30) having a fluid inlet (31) and at least one fluid outlet (33a), the control valve (30) being capable of adopting at least two states; wherein the control valve (30) - in a first state, connecting the fluid inlet (31) to the first fluid channel (7) of the fluid return device (1), and - In a second state, the fluid inlet (31) is connected to the inlet (4) of the quick discharge valve (3) of the fluid return device (1), and the first fluid channel (7) of the fluid return device (1) is connected to the at least one fluid outlet (33a).

7. The device according to claim 6, characterized in that The device comprises a muffler (41a) connected to the at least one fluid outlet (33a) of the control valve (30).

8. A method for operating a double-acting pneumatic cylinder (20; 200) using a fluid return device (1) according to claim 1 or 2, the cylinder having a first cylinder chamber (21) remote from the piston rod and a second cylinder chamber (22) on the piston rod side, It is characterized in that When the volume of the second cylinder chamber (22) decreases, at least a portion of the compressed air in the second cylinder chamber (22) flows back to the first cylinder chamber (21) via the discharge port (6) of the quick discharge valve (3).

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