Abstract: Pistons for a syringe and syringe systems are disclosed. The pistons may include a base with a first end, a second end opposite the first end, and a side portion extending between the first end and the second end. The piston may also include at least one engagement portion extending around the circumference of the side portion of the base. Another embodiment of the plunger head may include a proximal end, a distal end opposite the proximal end, and an intermediate portion connecting the proximal end and the distal end. The intermediate portion is tapered from the proximal end to the distal end. The syringe system includes a piston and a plunger rod. The plunger rod may include a first end and a second end with the first end pressingly contacting the distal end of the piston.

Abstract: A piston pump is provided comprising a cylinder with an inner cylinder wall. The piston pump comprises at least one working space including fluid intake and fluid outlet, a piston including a piston rod and a piston head. The piston head includes a lateral surface facing the cylinder wall, a front surface facing the working space, a rear surface and at least one piston head channel. Furthermore, the piston head's lateral surface is provided with a first projection and a second projection extending round the entire circumference of the lateral surface and in contact with the cylinder wall, thereby forming an annulus which is defined by the first projection, the second projection, the cylinder wall and possibly the cylinder head's lateral surface between the first and the second projections if the piston head is designed so that the projections are provided with an axial spacing between them.

Abstract: A piston and cylinder assembly includes a housing defining a bore. A piston is sized to reciprocate in the bore. A first sealing member provides a sealing engagement between the piston and a wall of the bore. A first bushing, of a first material, is around a first portion of the piston toward a first end of the piston. A second bushing, of a second material, is around a second portion of the piston toward a second end of the piston. The first and second bushings guide the piston within the bore. The first material is different than the second material.

Abstract: A piston device for internal combustion engines includes a first compression ring and a second compression ring in an outer circumference of a piston, wherein the second compression ring includes a notch extending from the inner circumference to the outer circumference on a lower surface of at least one of a pair of ends of the ring, and a gap between the ring ends at the notch on the second compression ring is larger than a gap between the ring ends of the first compression ring, and a gap between the ring ends at the section other than the notch on the second compression ring is the same or smaller than the gap between the ring ends of the first compression ring, and the second compression ring contains an outer circumferential surface comprised of a tapered surface decreasing the ring radial thickness towards the upper side, and an axial parallel surface formed below the tapered surface.

Abstract: In one aspect, a brake pump assembly with a hydraulic block and a pumping element including a polymer piston that is received in a piston bore. A circumference of the polymer piston defines a high-pressure seal slideably engaging adjacent structure. The polymer piston may include a peripheral sealing lip projecting primarily longitudinally from the polymer piston for sealing engagement with the piston bore. In another aspect, a brake pump assembly with a hydraulic block, a straight bore polymer piston, a peripheral sealing lip projecting from a proximal portion of the polymer piston, and a elastomeric seal mounted to a distal portion of the polymer piston, where the peripheral sealing lip selectively acts to depressurize fluid accumulating between the peripheral sealing lip and elastomeric seal.

Abstract: A dispenser for dispensing a liquid onto a substrate includes a dispenser body having an output and a reservoir in fluid communication with the output, the reservoir being defined by a wall and adapted to hold a supply of liquid to be dispensed. A piston is disposed in the reservoir and adapted to pressurize the liquid so that an amount of liquid is dispensed from the output of the dispenser. The piston includes a base portion having an outer periphery and having a first hardness, and a skirt portion integrally molded to the outer periphery of the base portion and having a second hardness lower than the first hardness. A two-shot molding operation may be used to form the piston with the base portion being, for example, formed in the first shot of the molding operation and the skirt portion being formed in the second shot of the molding operation.

Abstract: A metering receptacle has an elongate hollow body which at one end has a closable exit opening, and which at the other end is closable by way of a plastic plunger stopper. The plunger stopper is at the same time longitudinally displaceable in the hollow body by way of a plunger rod. The metering receptacle is configured such that the plunger stopper is formed of two parts, with a sealing stopper part of plastic which is rigidly positionable in the elongate hollow body and has a centric bore for the passage of the plunger rod, and with a longitudinally displaceable plunger part of lubricious plastic which is connected to the plunger rod.

Abstract: A piston assembly for a double-acting engine such as a double-acting Stirling engine. A pair of sealing rings located on opposite sides of a sealing washer are positioned between a base section and a dome section of a piston head. These sealing rings are alternatively urged into sealing engagement with the cylinder bore as the piston reciprocates. A single sealing ring design is also disclosed in which the sealing ring is urged into constant sealing engagement by positive pressure accumulated with an interior cavity in the piston head.

Abstract: Water well pump plunger efficiency is improved by providing a pair of upwardly open outwardly flared wall cups surrounding a pump plunger and supported in superposed relation by a sleeve in the lowermost cup. A fluid passageway through the base of the uppermost cup insures filling the lowermost cup on the plunger upstroke.

Abstract: An accumulator piston is formed as a two-piece plastic molding for simplifying its construction and for cost reduction and weight reduction purposes. The piston has a radially stepped construction in which each step includes a radial flange carrying an annular elastomeric sealing element. The sealing elements have deformable, resilient lips which slidably engage the side surfaces of a stepped cylinder in which the piston reciprocates. One of the elastomeric sealing elements is molded to an annular insert member that is seated in an annular recess formed in one end of the main piston body. The two-piece piston construction facilitates installation and removal of mold cavity members relative to the respective elastomeric sealing elements such that the mold cavity members can be of simplified economical construction.

Abstract: Portable lift structure for moving a support platform between a comparatively dry position above the surrounding deck of a liquid spa tank to a wetting position in the spa tank including two longitudinally extending structural members pivotally connected at corresponding top ends thereof to be moved between a portable and operating positions, one structural member serving as a mast to be removably mounted in the spa tank deck and the other as a platform mount, to be pivoted from above the surrounding spa tank deck to a position above the spa tank and lowered by a hydraulic cylinder and piston to a wetting position.

Abstract: A position-controlled actuator including a double acting pneumatic actuator, a selector valve which causes function of the actuator, a comparator which controls the action of the selector valve in response to a comparison between an input signal and a signal indicative of the position of the actuator, and a feedback link which provides the comparator with a signal indicative of the position of the actuator. The actuator would have oscillation damping seals such as seals of VITON brand fluorocarbon rubber.

Abstract: A swabbing apparatus has a plurality of swab cups molded on a single core, with at least two swab cups having a different fluid load carrying capacity, so that the swabbing apparatus will have a relatively broad fluid load carrying capacity. Each swab cup has one or more lips with the fluid load carrying capacity of a swab cup being determined primarily by lip thickness.

Abstract: A hydraulic jack includes a body (1) with front (2) and rear (3) covers and a rod (4) moving relative to said body (1) and having at least one projection made therein and mounting an additional member (7) and at least two grooves which form the respective projection (8) and of which each accomodates piston semi-rings (6) installed therein by pairs, the rod (4) portion having the projections (8) and the grooves forming a piston unit (5).

Abstract: Seal for maintaining gas-tight contact between casing wall and, particularly, automatic well swabs. The seal includes an upper portion containing a reinforcing tube and being minimally less in diameter than the casing interior, a tapering midsection and a lower skirt portion contacting the well casing. Also included is a secondary embodiment with an upper portion being substantially less in diameter than the casing interior and reinforcing ribs in the tapering midsection.

Abstract: Gas and oil well swabs, particularly a dynamic seal for maintaining gas-tight contact between the moving swab and the well casing. The seal includes a reinforcing tube and a flexible annulus having an upper throat portion complementally engaging the exterior of the reinforcing tube and a lower bell-shaped skirt portion, engageable with the well casing. The lower bell-shaped skirt portion of the seal defines an expansion chamber for the well gas, which lifts the swab.

Abstract: A piston-shaped bottom closure for a hollow container has a closing member arranged so that when the closure is inserted into a container the closing member extends transversely of an inner wall of the container, a hollow guiding member extending from the closing member in an axial direction so that in the inserted condition of the closure the guiding member is guided by the inner wall of the container, at least one sealing lip provided on the guiding member and abutting against the inner wall of the container in the inserted condition of the closure, and a cover member arranged on the closing member at its side facing toward a storage chamber of the container and having a contour substantially corresponding to the contour of the closing member, wherein the cover is composed of a material having a different elasticity than the closing and guiding members and the sealing lip and is provided with an edge which extends towards the guiding member and overlaps an outer edge of the closing member so as to be arrest

Abstract: A packer nose assembly for pumping downhole equipment of the free type into and out of a tubing string located within a borehole. The assembly includes a mandrel having a lower end portion attachable to the downhole equipment and an upper end portion terminating in the form of a fishing neck. One or more packers are slidably received in a telescoping manner upon the mandrel and fixed in spaced-apart relationship respective to one another by spaced sleeves which are likewise slidably received upon the mandrel. Each packer is cylindrical in form and includes a resilient cup member which is affixed to the mandrel by a mount member. A marginal end of the cup is in the form of a lip which circumferentially extends about the mandrel and is biased into sealed engagement with the tubing wall. A marginal end of the mount member is in the form of a skirt which protects the cup member from damage.