A sealing ring segment of a sealing ring assembly may include three layers. The middle layer is permeable to gas, thus allowing radial pressure-balancing on the sealing ring segment to reduce wear. The gas-permeable allows gas to permeate from a high-pressure region to a clearance gap between a radially outer surface of the segment and a bore of a cylinder. The flow of gas affects the pressure at the radially outer surface, thus reducing the resultant radial outward force on the segment, as compared to no gas permeation. The gas-permeable layer may be porous, sintered, or have any other suitable structure having suitable gas permeability properties. The gas-permeable layer may be positioned central or rearward axially, in relation to the outer layers. The gas-permeable layer may extend the full radial thickness of the sealing ring segment.

A cylinder coupling structure of a small air compressor according to the present invention, in which a cylinder is integrally coupled to a block by which a crankshaft is shaft-supported, wherein the block is provided with a supporting end by which the cylinder is pressed to be supported; a latching end is formed on the outer surface of the cylinder; and a press bolt is fastened to the block and a valve cover so that the valve cover presses the front end of the cylinder while the latching end of the cylinder is latched and supported on the supporting end.

A portable pump is provided including an electric motor having a drive shaft connected to a gear assembly to drive a reciprocating air compressor arrangement. The reciprocating air compressor arrangement includes a crank that drives a connecting rod and a piston within a cylinder. The connecting rod has a first end and a second end and the first end of the rod is connected to the crank while the second end of the rod connected to the piston (to drive the piston in the cylinder and provide compression). The second end of the connecting rod is connected to the piston via a pin. The piston includes a sealing arrangement. A control unit is provided which is in electrical communication with the electric motor and the air compressor to control the operation of the pump arrangement. A power supply is also provided in electrical communication with the control unit to supply power to the control unit and electric motor. The pump is provided within a housing which accommodates the electric motor, the gear assembly, the reciprocating air compressor, the control unit and the power supply. A outlet connected to the reciprocating air compressor is also provided so as to engage with an object to be pumped.

Described herein is a packing box for mounting on a machinery shaft. In accordance with one aspect, the packing box housing defines a central opening for insertion of a movable machinery shaft with a hollow passageway surrounding the central opening to form a path for the flow of a fluid coolant. The passageway is provided with a fluid inlet port and a fluid outlet port opening onto the outer surface of the packing box housing, and it is formed by a single conduit or by a plurality of conduits obtained through additive manufacturing process and connected in series or in parallel to wound around the central opening.

A method is disclosed for producing a piston (8) having a circumferential seal in the form of a circular cup seal (16). In a functional, installed state, the cup seal (16) has a profile consisting of a leg held in the piston (8) and aligned radially with respect to the piston longitudinal axis (19) in a radial region (17) and of a leg which is bent by approximately 90 into an axial region (18) and is aligned approximately parallel to the piston longitudinal axis (19). The cup seal (16) is mounted in a mold as a flat or arched preform (21, 21a) with a radial region (17a, 17b) which forms the approximately radial leg, aligned with the piston longitudinal axis (19). A circumferential region (18a, 18b) projecting radially beyond the mold cavity is shaped into the axial region (18) after removing the piston from the mold to obtain the functional contour of the installed state of the cup seal (16).

A wobble piston is provided to be used in an air compressor for providing compressed air, and includes a piston cap having a generally flat first plate and a peripheral edge extending downwardly from the first plate. A connecting support rod is connected to the piston cap, and a compression ring is clamped between the edge of the piston cap and the support rod in complementary fashion. Upon assembly between the cap and the support rod, the compression ring has an angled side wall that is bent upwardly inwardly at a predetermined obtuse angle relative to a longitudinal axis of a cylinder.

Described herein is a packing box for mounting on a machinery shaft. In accordance with one aspect, the packing box housing defines a central opening for insertion of a movable machinery shaft with a hollow passageway surrounding the central opening to form a path for the flow of a fluid coolant. The passageway is provided with a fluid inlet port and a fluid outlet port opening onto the outer surface of the packing box housing, and it is formed by a single conduit or by a plurality of conduits obtained through additive manufacturing process and connected in series or in parallel to wound around the central opening.

The packing seal for a piston compressor, having a longitudinal axis L as well as, following one after the other in the direction of the longitudinal axis L, a fastening part and a cylindrical part, wherein a magnetic bearing and at least one chamber ring with a sealing ring arranged therein are arranged following one after the other in the direction of the longitudinal axis L in the cylindrical part, wherein the magnetic bearing includes at least one controllable electromagnet.

A reciprocating jetting water pump primarily for use on a vacuum truck is disclosed. The jetting water pump includes a pair of reciprocating pistons that are each movable within an outer cylinder mounted to a center block. Each of the outer cylinders is mounted to the center block by a plurality of tie-rod that each extend between the center block and an end plate. An airflow passageway is formed in the center block to vent air trapped within the open interior of the first outer cylinder during reciprocating movement of the piston in the first outer cylinder. A control system mounted to the vacuum truck senses the pressure of water leaving the jetting water pump and controls the supply of pressurized hydraulic fluid to the jetting water pump to maintain the water pressure at an operator selected value.

A pump comprises at least one piston slidable within an opening along a movement direction in order to vary the volume of a chamber. The pump further comprises a casing within which a driving device is housed for moving the piston, and a head within which the chamber is at least partially obtained, the chamber being partially delimited by the piston. A high pressure sealing element is located in a proximal position with respect to the chamber and a low pressure sealing element is located in a distal position with respect to the chamber to stop any quantities of liquid that the high pressure sealing element has let through. The high pressure sealing element is housed inside the head and the low pressure sealing element is housed inside the casing.