Drive unit

Abstract

The drive unit includes a plunger assembly having a first working chamber and a plunger arranged to reciprocate axially within the first working chamber; a valve housing having a high-pressure connection and a low-pressure connection; a second working chamber arranged within the valve housing and fluidly connected to the first working chamber; a valve seat ring having a high-pressure valve seat open to the second working chamber and a low-pressure valve seat open to the second working chamber; an inlet valve arranged between the high-pressure connection and the valve seat ring on the high-pressure valve seat; and an outlet valve arranged between the low-pressure connection and the valve seat ring on the low-pressure valve seat. The opening and closing of at least the inlet valve is controlled via the outlet valve, and the opening and closing of the outlet valve is controlled via a valve control unit. In the actuated position, the outlet valve is closed and the inlet valve is moved to an open position by the outlet valve, allowing high-pressure fluid supplied via the high-pressure connection to the second working chamber via the second working chamber. In the non-actuated position, the outlet valve is open and the inlet valve is closed. After the plunger is actuated, low-pressure fluid is discharged from the first working chamber via the second working chamber and the low-pressure connection. Here, at least one plunger may be coupled to a consumer.

Description

[Technical Field]

[0001] The invention relates to a drive unit according to the preamble of claim 1 and to the use of such a drive unit. [Background technology]

[0002] In a typical drive unit, a crankshaft or the like is driven via one or more plungers. The plungers are driven by a supply of fluid under high pressure that enters the working chamber of the plunger arrangement. After the plunger is driven, the pressure of the fluid decreases due to the expansion of the working chamber, and the fluid is forced back from the working chamber by the plunger through a pressure line as the plunger returns to its initial position. The stroke of these plungers is controlled by a valve arrangement with inlet and outlet valves, which are controlled by a valve control system.

[0003] Typically, separate inlet and outlet valves are used for this purpose, each valve being separately controlled by a valve control unit. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to make it possible to operate such a drive unit with reduced energy input to the control system. [Means for solving the problem]

[0005] This first object is achieved by a drive unit having the features of claim 1.

[0006] A drive unit according to the present invention includes a plunger device having a first working chamber and a plunger arranged to be reciprocable in an axial direction within the first working chamber.

[0007] The drive unit further includes a valve housing having a high-pressure connection and a low-pressure connection, and a valve seat ring disposed within the valve housing, the valve seat ring having a second working chamber fluidly connected to the first working chamber, a high-pressure valve seat open to the second working chamber, and a low-pressure valve seat open to the second working chamber.

[0008] An inlet valve is disposed between the high pressure connection and a valve seat ring on the high pressure valve seat. An outlet valve is disposed between the low pressure connection and a valve seat ring on the low pressure valve seat. The opening degree of at least the inlet valve is controlled via the outlet valve, and the opening and closing of the outlet valve is controlled via the valve control unit.

[0009] In the operating position, the outlet valve is closed and the inlet valve is moved to the open position by the outlet valve, and high-pressure fluid supplied via the high-pressure connection is supplied to the first working chamber via the second working chamber. In the non-operating position, the outlet valve is open and the inlet valve is closed, which drives the plunger, and then low-pressure fluid is discharged from the first working chamber via the second working chamber and the low-pressure connection. At least one plunger (in combination with the crankshaft) can be coupled to a consumer.

[0010] Using such a drive unit, it is possible to reduce the control energy to the valve arrangement of the inlet and outlet valves, since only the outlet valve needs to be actuated, and the inlet valve can be opened by its operation.

[0011] Furthermore, the compact design of the inlet and outlet valves allows the overall drive unit to be smaller, thus reducing the cost of the drive unit.

[0012] A further advantage of the drive unit is that it reduces the need for flexible seals in high pressure areas, which can cause pressure dependent friction and adversely affect valve switching times, or, if labyrinth seals are selected, introduce additional leakage and reduce efficiency. Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0013] According to an advantageous embodiment, the outlet valve has a tappet protruding into the second working chamber, the tappet having a first sealing surface that contacts the sealing surface of the low-pressure valve seat in the closed position of the tappet, and the inlet valve has a closure body having a second sealing surface that contacts the sealing surface of the high-pressure valve seat in the closed position. When the tappet moves from the open position to the closed position, it pushes the closure body from the closed position to the open position.

[0014] The mechanical coupling of the inlet and outlet valves allows for reliable control of the inlet valve through the outlet valve. According to an advantageous development, in the closed position of the outlet valve, the first sealing surface of the tappet rests against the sealing surface of the low-pressure valve seat, and in the closed position of the inlet valve, the closing body rests against the sealing surface of the high-pressure valve seat.

[0015] According to an advantageous development, the first sealing surface is configured as a conical annular surface and connects a first cylindrical tappet part extending through the second working chamber of the valve seat ring with a second cylindrical tappet part extending in the direction of the low-pressure connection.

[0016] The tappet is preferably guided in the low-pressure part of the housing body of the valve housing or in a guide bush arranged in the housing body only in the region of the part of the tappet extending from the second cylindrical tappet part away from the valve seat ring, and in this region is sealed by a low-pressure seal configured as an elastically deformable low-pressure seal or a labyrinth seal.

[0017] This allows a dedicated elastically deformable seal to be positioned in the low pressure area to seal the tappet from the surrounding environment and the valve control section. According to a further advantageous development, the inlet valve has an energy accumulator in the form of a compression spring, which urges the closing body into the closed position.

[0018] In particular, this allows the tappet of the outlet valve to rest solely on the closure body of the inlet valve without having to move to the closed position. According to a preferred embodiment, the closure body is configured as a sphere, which has the particular advantage that the spherical surface causes little turbulence when the inlet valve is open.

[0019] In one advantageous embodiment, the outlet valve is pneumatically, electrically or hydraulically controlled. In one advantageous embodiment, the valve control unit is coupled to a position sensor, which detects the rotational position of the crankshaft and thus the position of the plunger within the first working chamber.

[0020] According to a further preferred embodiment, at least three, preferably five, plunger devices are provided, each plunger being assigned an inlet valve and an outlet valve.

[0021] The use of a drive unit for controlling pressure in a hydraulic process assembly according to the present invention is characterized in that the drive unit is configured as described above, and the drive unit is coupled to the process assembly and coupled to a mechanism using rotational motion transmitted to the crankshaft via the crankshaft to a generator for generating electrical energy or via the crankshaft to the crankshaft. [Brief explanation of the drawings]

[0022] In the following, preferred embodiments will be described in more detail with reference to the accompanying drawings. [Figure 1] 3 is a schematic cross-section through a variant of an embodiment of a drive unit according to the invention; [Figure 2] 2 is an enlarged detailed view of the cross section of the drive unit marked II and III in FIG. 1, showing the inlet and outlet valves and valve seat rings, with the outlet valve closed and the inlet valve open. [Figure 3] FIG. 3 is an enlarged detail view corresponding to FIG. 2, with the outlet valve open and the inlet valve closed. DETAILED DESCRIPTION OF THE INVENTION

[0023] In the following description of the drawings, terms such as top, bottom, left, right, front, rear, etc. refer solely to exemplary representations and to the positions of drive units, plunger arrangements, plungers, valve seat rings, inlet valves, outlet valves, etc. in the selected figures. These terms should not be understood as limiting, i.e., they vary with different operating positions or mirror-symmetric configurations.

[0024] In FIG. 1, the reference number 1 is used to indicate a variant embodiment of the drive unit. The drive unit 1 basically consists of a plunger device 2 with a plunger 22, which is arranged in an operating chamber of a plunger housing that surrounds the plunger 22, and which is reciprocable along its longitudinal axis, which in the illustrated embodiment is coaxial. The plunger 22 together with the plunger housing 23 is accommodated in a plunger frame 10.

[0025] It is also conceivable to configure the drive unit 1 with a plurality of such plungers arranged therein, in which case the plungers are preferably arranged adjacent to each other in one or several rows.

[0026] Preferably, the plunger 22 is connected to one end thereof with a crankshaft 12 or the like, so that the movement of the plunger 22 can directly or indirectly drive a consumer. The crankshaft 12 is connected to the plunger 22 via a connecting rod 13 and a connecting piece 14 attached to the connecting rod 13.

[0027] It is also conceivable that the drive unit 1 is used for energy recovery, in which case the fluid that has been pressurized in the previous process is supplied to the drive unit 1, and a generator is driven, for example, via a plunger driven by the high pressure and a crankshaft connected to the plunger, and this generator converts the energy released by the expansion of the fluid under high pressure into electricity.

[0028] A high-pressure line 8 arranged in a connection frame 9 is connected to the first working chamber 21 of the plunger device 2 , and this high-pressure line 8 opens into the valve housing 3 . 1, the valve housing 3 has a housing body 33, the underside of which is connected a high-pressure connection 31. The high-pressure connection 31 is accommodated in a further frame 11 attached to the housing body 33 of the valve housing 3.

[0029] The housing body 33 of the valve housing 3 itself also has a low pressure connection 32 . A valve seat ring 4 is disposed within the cavity of the housing body 33 .

[0030] The valve seat ring 4 has a second working chamber 41 configured to be fluidly connected to the first working chamber 21, a high-pressure valve seat 42 that opens into the second working chamber 41, and a low-pressure valve seat 43 that opens into the second working chamber 41.

[0031] The inlet valve 5 is arranged between the high pressure connection 31 and the valve seat ring 4 on the high pressure valve seat 42 . The outlet valve 6 is arranged between the low pressure connection 32 and the valve seat ring 4 on the low pressure valve seat 43 . The inlet valve 5 is opened by the movement of the outlet valve 6 .

[0032] The outlet valve 6 is opened and closed via a valve control unit 7, shown by way of example in Figure 1. No separate valve control unit is provided for opening and closing the inlet valve 5.

[0033] In the embodiment shown here according to Figures 2 and 3, both the high pressure valve seat 42 and the low pressure valve seat 43 are configured as approximately annular recesses surrounding the second working chamber 41, with their respective sealing surfaces 421, 431 blocking or releasing the flow of fluid together with the inlet valve 5 and outlet valve 6, respectively.

[0034] In a variant of the embodiment shown here, the outlet valve 6 has a tappet 61 protruding into the second working chamber 41, with a first sealing surface 614 integrally formed on its outer circumferential surface, which in the closed position of the tappet 61 is in direct contact with the sealing surface 431 of the low-pressure valve seat 43, i.e., in order to seal the second working chamber 41 on the low-pressure side, the tappet 61 is in direct contact with the valve seat ring 4 (the sealing surface 431 of the low-pressure valve seat 43 of the valve seat ring 4).

[0035] In a variant of the embodiment shown here, the first sealing surface 614 is configured as a conical annular surface connecting a first cylindrical tappet portion 612 extending through the second working chamber 41 of the valve seat ring 4 with a second cylindrical tappet portion 613 extending in the direction of the low-pressure connection 32.

[0036] The end face 611 of the tappet 61 is configured to fit against the contact surface of the closure body 51 of the inlet valve 5 .

[0037] The part of the tappet 61 that extends away from the first cylindrical tappet part 612 and from the second cylindrical tappet part 613 is guided exclusively in the low-pressure part of the housing body 33 of the valve housing 3, or preferably in a guide bushing arranged in the housing body 33 and sealed by an elastically deformable low-pressure seal 15.

[0038] The low pressure seal may also be configured as a labyrinth seal to reduce the frictional component of the valve device. The low pressure part of the housing body 33 is understood to be that part of the housing body 33 that is not exposed to high pressure. As can be seen in Figures 2 and 3, this low pressure part extends above the low pressure valve seat 43 towards the low pressure connection 32 and beyond the low pressure connection 32 into the area of ​​the housing body 33 that guides the tappet 61.

[0039] The closing body 51 , which here is preferably spherical, is pressed against the contact surface 611 of the tappet 61 from the side opposite the tappet 61 by an energy store holder which is preloaded by a compression spring or other energy store 54 .

[0040] As shown in FIG. 1, the valve control unit 7 is preferably configured as a pneumatic control unit and has a compressed air inlet 75. When compressed air enters the valve control unit 7, the valve control unit 7 presses a disc 71 downward against a cover 73, and the disc 71 drives the tappet 61 to close the outlet valve and simultaneously open the inlet valve.

[0041] When the compressed air is released again to open the outlet valve 6 , the disc 71 which drives the tappet 61 is pushed back into its starting position against the cover 73 by a compression spring 74 in the embodiment shown.

[0042] The valve control unit 7 preferably has a housing part 72 with an internal thread that is screwed onto the external thread of the part 34 of the valve housing 3. A flange connection between the valve control unit 7 and the valve housing 3 is also conceivable, for example.

[0043] As an alternative to a spherical closure body 51, a cylindrical or conical closure body 51 is also conceivable. The energy accumulator 54 , which is here configured as a compression spring, is accommodated in a cylindrical recess in the energy accumulator holder and is supported on a step in a closure body receptacle 56 in the valve holder 55 .

[0044] In a possible design variant in which the closing body 51 is directly connected to the tappet 61, the energy accumulator 54 is not necessarily required. In this case, a compression spring 74 acting on the disk 71 of the valve control unit 7 can take over this function. The closure receiver 56 is fluidly connected to the high pressure connection 31 .

[0045] The fluid under high pressure can flow through the passage opening 52 provided in the energy accumulator holder, past the closure body 51 and into the second working chamber 41 of the valve seat ring via the closure body receiving portion 56, provided that the second sealing surface 511 of the closure body 51 is not stationary against the sealing surface 421 of the high-pressure valve seat 42 against which the closure body 51 is pressed by the biasing force of the spring holder.

[0046] In the position sealing the second working chamber 41 , the closing body 51 bears directly against the sealing surface 421 of the high-pressure valve seat 42 of the valve seat ring 4 as well as against the first sealing surface 614 of the tappet 61 .

[0047] This means that no elastic sealing elements are installed in the high pressure range, which would cause pressure-dependent friction and adversely affect the valve switching time. To drive the plunger 22 in the first working chamber 21 from top dead center as shown in FIG. 1, the inlet valve 5 must be opened.

[0048] To open the inlet valve 5 , the tappet 61 presses against the closure body 51 , forcing the closure body 51 downwards and away from the sealing surface 421 of the high-pressure valve seat 42 against the force of the energy accumulator 54 . The inlet valve 5 is opened by the movement of the outlet valve 6 . The outlet valve 6 is opened and closed by a valve control unit 7, illustrated in FIG. 1, as described above.

[0049] The mechanical or geometric coupling between the tappet 61 of the outlet valve 6 and the closing body 51 of the inlet valve 5 allows the outlet valve 6 to be closed and the inlet valve 5 to be moved to the open position by the outlet valve 6, as shown in Figure 2, in the working position in which the plunger 22 drives the crankshaft by its movement with the help of high-pressure fluid supplied in the first working chamber 21.

[0050] At the bottom dead center of the plunger device 2, the outlet valve 6 is opened. As shown in Fig. 3, since the outlet valve 6 is opened and the inlet valve 5 is closed, after the plunger 22 is driven, the low-pressure fluid can be discharged from the first working chamber 21 through the second working chamber 41 and the low-pressure connection 32.

[0051] 2 and 3 shows that when the outlet valve 6 is open, the conical ring-shaped first sealing surface 614 of the tappet 61 is not in contact with the sealing surface 431 of the low-pressure valve seat 43.

[0052] In this regard, the downward movement of the tappet 61 in the Z direction (as shown in FIG. 2) allows the inlet valve 5 to be opened while simultaneously closing the outlet valve 6, with the closure body 51 being pressed against the sealing surface 421 of the high-pressure valve seat 42.

[0053] Furthermore, due to the above arrangement, dynamic sealing elements, in particular elastic sealing lips or labyrinth seals, can be completely omitted in the high pressure region, since no moving parts need to be sealed from the outside in the high pressure region.

[0054] The outlet valve 6 is preferably pneumatically, electrically or hydraulically controlled. The drive unit 1 described above can be used in a first application for energy recovery in a hydraulic process assembly for generating electrical energy. For this purpose, a generator for generating electrical energy is coupled to at least one plunger 22 via the crankshaft 12.

[0055] In a second application of the drive unit 1, a mechanism utilizing the rotational motion transmitted to the crankshaft is coupled via the crankshaft 12. The mechanism utilizing the rotational motion can be, for example, a pump, the plunger of which is coupled to the crankshaft 12. Other consumers for utilizing the kinetic rotational energy generated by the drive unit 1 are also conceivable. [Explanation of symbols]

[0056] List of symbols 1 Drive unit 2 Plunger device 21 First working chamber 22 Plunger 23 Plunger housing 3 Valve Housing 31 High voltage connection 32 Low-voltage connection 33 Housing body 34 flange 4 Valve seat ring 41 Second working chamber 42 High-pressure valve seat 421 sealing surface 43 Low-pressure valve seat 431 sealing surface 44 Annular 45 cross holes 5 Inlet Valve 51 Closed body 511 Second sealing surface 52 Passage opening 53 Spring retainer 54 Energy Accumulator 55 Valve holder 56 Closure body receiving part 6 Outlet Valve 61 Tappet 611 End face 612 First tappet part 613 Second tappet part 614 First sealing surface 7 Valve Control Unit 71 discs 72 flange 73 Cover 74 Compression spring 75 Compressed air inlet 8 High-voltage lines 9 Connecting Frame 10 Plunger Frame 11 frames 12 crankshaft 13 Connecting rod 14 Connecting piece 15 Low pressure seal

Claims

1. A drive unit (1), a plunger device (2) including a first working chamber (21) and a plunger (22) arranged to reciprocate in an axial direction within the first working chamber (21); a valve housing (3) with a high pressure connection (31) and a low pressure connection (32); a valve seat ring (4) provided with a second working chamber (41) disposed within the valve housing (3) and fluidly connected to the first working chamber (21), a high-pressure valve seat (42) open to the second working chamber, and a low-pressure valve seat (43) open to the second working chamber; an inlet valve (5) disposed between the high-pressure connection (31) and a valve seat ring (4) on a high-pressure valve seat (42); A drive unit (1) comprising a low-pressure connection (32) and an outlet valve (6) arranged between a valve seat ring (4) on a low-pressure valve seat (43), The opening degree of at least one inlet valve (5) is controllable via an outlet valve (6), and the opening and closing of the outlet valve (6) is controllable via a valve control unit (7); In the working position, the outlet valve (6) is closed and the inlet valve (5) is moved to an open position by the outlet valve (6), so that the high-pressure fluid supplied via the high-pressure connection (31) is supplied to the first working chamber (21) via the second working chamber (41); In the inactive position, the outlet valve (6) is open and the inlet valve (5) is closed, and after the plunger (22) is actuated, low pressure fluid is discharged from the first working chamber (21) via the second working chamber (41) and the low pressure connection (32); A drive unit (1) characterized in that at least one plunger (22) is coupled to a consumer.

2. 2. The drive unit (1) according to claim 1, wherein the outlet valve (6) has a tappet (61) protruding into the second working chamber (41), the tappet (61) having a first sealing surface (614) that abuts against a sealing surface (431) of the low-pressure valve seat (43) in its closed position, and the inlet valve (5) has a closing body (51) that abuts against a sealing surface (421) of the high-pressure valve seat (42) in its closed position, and wherein the tappet (61) pushes the closing body (51) from the closed position to the open position when moving from the open position to the closed position.

3. 3. The drive unit (1) according to claim 2, wherein in the closed position of the outlet valve (6), the first sealing surface (614) of the tappet (61) contacts the sealing surface (431) of the low-pressure valve seat (43), and in the closed position of the inlet valve (5), the closing body (51) contacts the sealing surface (421) of the high-pressure valve seat (42).

4. 4. The drive unit (1) according to claim 3, wherein the first sealing surface (614) is configured as a conical annular surface connecting a first cylindrical tappet portion (612) extending through the second working chamber (41) of the valve seat ring (4) with a second cylindrical tappet portion (613) extending in the direction of the low-pressure connection (32).

5. 5. The drive unit (1) according to claim 4, wherein the tappet (61) is guided in the low-pressure part of the housing body (33) of the valve housing (3) or in a guide bush arranged in the housing body (33) only in the region of the part of the tappet (61) extending from the second cylindrical tappet part (613) in a direction away from the valve seat ring (4), and is sealed in this region by an elastically deformable low-pressure seal (15) or by a low-pressure seal (15) configured as a labyrinth seal.

6. 6. A drive unit (1) according to any one of claims 2 to 5, wherein the inlet valve (5) comprises an energy accumulator (54), in particular in the form of a compression spring, which biases the closing body (51) into the closed position.

7. 7. A drive unit (1) according to any one of claims 2 to 6, wherein the closure body (51) is configured in a spherical, conical or cylindrical shape.

8. 8. A drive unit (1) according to any one of the preceding claims, wherein the outlet valve (6) is pneumatically, electrically or hydraulically controlled.

9. 9. A drive unit (1) according to any one of claims 1 to 8, wherein the valve control unit (7) is connected to a position sensor, which provides the position of a drive shaft connected to the plunger (22) or the position of the plunger (22) in the first working chamber (21).

10. 10. A drive unit (1) according to any one of claims 1 to 9, wherein at least three, preferably five, plunger devices (2) are provided, each plunger device comprising a plunger (22), each plunger being assigned an inlet valve (5) and an outlet valve (6).

11. 11. Use of a drive unit (1) for energy recovery in a hydraulic process assembly, the drive unit (1) being configured according to any one of claims 1 to 10, the drive unit (1) being connected to the hydraulic process assembly, and the plunger (22) being connected to a generator that generates electrical energy via a crankshaft (12) or a mechanism that utilizes rotational motion transmitted to the crankshaft via the crankshaft (12).

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