Abstract: A hydraulic piston machine is described comprising a piston (1) having a hollow (2) secured by a wall (3) and an insert (4) arranged in the hollow. Such a machine should have a high efficiency at low costs. To this end the insert (4) comprises a section (29) which extends out of the hollow (2).

Abstract: A system for reverse osmosis, RO, including a first RO stage (10) with a first feed inlet (11), a first brine outlet (12), and a first permeate outlet (13); a second RO stage (20) with a second feed inlet (21), a second brine outlet (22), and a second permeate outlet (23); and a pressure exchanger, PE, (40) connected between the second brine outlet (22) and the first feed inlet (11), wherein a first pressure difference ?p1 between the first brine outlet (12) and the second feed inlet (21) corresponds to a second pressure difference ?p2 between the second brine outlet (22) and the pressure exchanger (40). The invention further discloses a method for operating such a system for reverse osmosis (100).

Abstract: A hydraulic machine includes a first member (1) having a first structure (2) for a hydraulic medium opening in a first interface surface (3) and a second member having a second structure for the hydraulic medium opening in a second interface surface is described, the first interface surface (3) being in contact with the second interface surface, wherein at least one of the members (1) is provided with a support element (6) surrounding the member (1). Such a machine should have a good efficiency. To this end the support element (6) has a strength varying in circumferential direction around the member (1) and/or in thickness direction in a middle region of the member (1).

Abstract: A piston (1) having a piston shaft (2), a ball head (3) at one end of the piston shaft (2), and a slider shoe (4) mounted to the ball head (3), wherein the ball head (3) has a through channel (5), the slider shoe (4) has a sliding surface (6) and a through hole (7) in communication with an end of the through channel (5), and a plastic material (8) is arranged in a gap between the slider shoe (4) and the ball head (3) and forms an inner coating (9) of the through hole (7). The production of such a piston should be facilitated. To this end a sealing surface (14) is arranged at the end of the through channel (5) wherein the sealing surface (14) surrounds the opening of the through channel (5) into the through bore (7) and an inner diameter of the sealing surface (14) is smaller than an inner diameter of the inner coating (9) of the through bore (7).

Abstract: A piston (1) of a hydraulic piston machine is described, the piston (1) having a hollow (2) surrounded by a wall (3) and an insert (4) arranged in the hollow (2). Such a piston is used to have a piston machine with high efficiency at low costs. To this end at least two pliable rings (12, 13) are arranged between the insert (4) and the wall (3).

Abstract: A piston (1) having a piston shaft (2), a ball head (3) at one end of the piston shaft (2), and a slider shoe (4) mounted to the ball head (3), wherein the ball head (3) has a through channel (5), the slider shoe (4) has a sliding surface (6) and a through hole (7) in communication with an end of the through channel (5), and a plastic material (8) is arranged in a gap between the slider shoe (4) and the ball head (3) and forms an inner coating (9) of the through hole (7). The production of such a piston should be facilitated. To this end a sealing surface (14) is arranged at the end of the through channel (5) wherein the sealing surface (14) surrounds the opening of the through channel (5) into the through bore (7) and an inner diameter of the sealing surface (14) is smaller than an inner diameter of the inner coating (9) of the through bore (7).

Abstract: A tube assembly (12) including an inner tube (13) having an outer thread (15), an outer tube (14) having an inner thread (16) engaging the outer thread (15), at least for securing an angular position between the inner tube (13) and the outer tube (14) is provided. Such a tube assembly should facilitate mounting and maintenance of a reverse osmosis system. To this end, the inner tube (13) includes at least an groove (17) on its outer surface and the outer tube (14) includes an recess (18) on its inner surface, wherein a blocking element is arranged in a space formed by the recess (18) and the groove (17) in overlapping relation with the groove (17) and the recess (18).

Abstract: A hydraulic machine includes a first member (1) having a first structure (2) for a hydraulic medium opening in a first interface surface (3) and a second member having a second structure for the hydraulic medium opening in a second interface surface is described, the first interface surface (3) being in contact with the second interface surface, wherein at least one of the members (1) is provided with a support element (6) surrounding the member (1). Such a machine should have a good efficiency. To this end the support element (6) has a strength varying in circumferential direction around the member (1) and/or in thickness direction in a middle region of the member (1).

Abstract: A pressure exchanger with a valve system includes a cylinder barrel (1), two valve plates (2) and two port plates (3, 4), wherein the cylinder barrel (1) has at least one cylinder (7) which accommodates a piston (8). The objective is to provide a pressure exchanger with low wear and a low maintenance effort. This objective is solved by a pressure exchanger including a piston (8) braking system and that the piston (8) includes a pressure relief arrangement.

Abstract: A valve plate assembly (1) of a hydraulic axial piston machine is described, the valve plate assembly comprising a wear plate (2) made of a ceramic material surrounded by a compression ring (4). Such a valve plate assembly should be produced and maintained in a cost-effective manner. To this end, the wear plate (2) is connected to a support plate (3) by means of the compression ring (4).

Abstract: A tube assembly (12) including an inner tube (13) having an outer thread (15), an outer thread (14) having an inner thread (16) engaging the outer thread (15), at least for securing an angular position between the inner tube (13) and the outer tube (14) is provided. Such a tube assembly should facilitate mounting and maintenance of a reverse osmosis system. To this end, the inner tube (13) includes at least an groove (17) on its outer surface and the outer tube (14) includes an recess (18) on its inner surface, wherein a blocking element is arranged in a space formed by the recess (18) and the groove (17) in overlapping relation with the groove (17) and the recess (18).

Abstract: A hydraulic axial piston machine (1) is described, the machine comprising a housing, a cylinder block (2) rotatably mounted in the housing about an axis or rotation (7) and having at least one cylinder (3), and a valve arrangement (4) between the cylinder block (2) and the housing, the valve arrangement having a first part (4) rotating with the cylinder block (2) and a second part mounted stationary with respect to the housing. Such a machine should have a high efficiency. To this end the first part (4) comprises an elastically deformable spring section (9).

Abstract: A valve plate assembly (1) of a hydraulic axial piston machine is described, the valve plate assembly comprising a wear plate (2) made of a ceramic material surrounded by a compression ring (4). Such a valve plate assembly should be produced and maintained in a cost-effective manner. To this end, the wear plate (2) is connected to a support plate (3) by means of the compression ring (4).

Abstract: A hydraulic machine is described comprising a first part (1, 4) and a second part (7, 8), wherein the first part (1, 4) and the second part (7, 8) are movable relatively to each other in abutting relation, the first part (1, 4) comprises a pressure chamber (2) having a pressure chamber opening (6) in a contact face (5) contacting a sealing face (9) of the second part (7, 8), the second part (7, 8) comprises a low pressure area (10) connected to a low pressure opening (11) in the sealing face (9) and a high pressure area (12) connected to a high pressure opening (13) in the sealing face (9), wherein during a movement of the first part (1, 4) with respect to the second part (7, 8) in a moving direction (14) the pressure chamber opening (6) comes alternatingly in overlap with the low pressure opening (11) and the high pressure opening (13). Such a machine should be flexible in operation with low risk of damages caused by cavitation.

Abstract: A piston (1) of a hydraulic piston machine is described, the piston (1) having a hollow (2) surrounded by a wall (3) and an insert (4) arranged in the hollow (2). Such a piston is used to have a piston machine with high efficiency at low costs. To this end at least two pliable rings (12, 13) are arranged between the insert (4) and the wall (3).

Abstract: A hydraulic piston machine is described comprising a piston (1) having a hollow (2) secured by a wall (3) and an insert (4) arranged in the hollow. Such a machine should have a high efficiency at low costs. To this end the insert (4) comprises a section (29) which extends out of the hollow (2).

Abstract: A method for producing a water-hydraulic machine having a first member (1) and a second member (2) in sliding contact with a contact surface (3) of the first member (1), wherein the second member (2) comprises a surface made of a friction reducing plastic material and the contact surface (3) is a metallic surface, is disclosed. The machine should have a low risk of damages. To this end, the method includes the steps of using a first member (1) comprising a first part (4) having the contact surface (3) and a second part (5), using a high temperature hardening process at a temperature of at least 1000° C. to give a deep surface hardening of the contact surface (3) of the first part (4), machining of the first part (4) to the desired geometry, assembling the first part (4) and the second part (5) to form the first member.

Abstract: A hydraulic machine is described having a first part (2) and a second part (3) moveable relative to said first part (3), one of said first part (2) and said second part (3) having a first land (9) resting against the other one of said second part (3) and said first part (2), having a predetermined first height (H1), and being arranged between a high pressure area (7) and a low pressure area (8). Such a machine should have a long working life. To this end a second land (10) having a predetermined second height (H2) smaller than said first height (H1) is located adjacent to said first land (9).

Abstract: A pump device (1) is provided comprising: a shaft (2), rotor means (3a, 3b) fixed to said shaft (2) in rotational direction, said rotor means (3a, 3b) having pressure chambers (5a, 5b) the volume of which varying during a rotation of said rotor means (3a, 3b), port plate means (15a, 15b) having a through going opening (16a, 16b) for each of said pressure chambers (5a, 5b) and being connected to said rotor means (3a, 3b) in rotational direction, and valve plate means (17a, 17b) cooperating with said port plate means (15a, 15b). It is intended to pressurize a high volume of fluid, in particular water, within a limited space.

Abstract: A pump arrangement (1) is provided comprising a driving shaft (2), cylinder drum means (3a, 3b) fixed to said shaft (2) in rotational direction and having a plurality of cylinders (6a, 6b), and a piston (7a, 7b) in each cylinder, each piston (7a, 7b) having a slide shoe (8a, 8b) in contact with driving surface means (8a, 8b). Such a pump arrangement should produce a pressure with low undulations. To this end said cylinder drum means (3a. 3b) comprise at least a first cylinder drum (3a) and a second cylinder drum (3b), said cylinder drums (3a, 3b) being fixed to said common shaft (2) in rotational direction, wherein the cylinder drums (3a, 3b) are offset with respect to each other in rotational direction.