A hydraulic cylinder unit (1) having a hydraulic cylinder (2), a piston (3) which can be moved in the hydraulic cylinder (2), and a servo valve (7). The piston (3) separates working volumes (5A, 5B) of the hydraulic cylinder unit (1) from one another. The servo valve (7) is connected to a hydraulic pump (8), a tank (9), and the working volumes (5A, 5B). The servo valve (7) is supplied with a pump pressure (pP) via the hydraulic pump (8). The tank (9) has a tank pressure (pT). The servo valve (7) is adjusted to a defined valve position (y). A piston position (z) of the piston (3) in the hydraulic cylinder (2) and working pressures (pA, pB) which are applied to the working volumes (5A, 5B) are detected. An analysis device (12) ascertains a leakage coefficient () of the hydraulic cylinder unit (1) using the piston position (z), the working pressures (pA, pB), the valve position (y), the pump pressure (pP), and a value which represents the tank pressure (pT) in connection with time-invariant parameters of the hydraulic cylinder unit (1).

A system can include an actuator with a piston rod that displaces in response to pressure in the actuator, a seal assembly that seals about the piston rod and includes seal cartridges, each including a dynamic seal sealingly engaging the rod, and each including a static seal sealingly engaging a seal assembly housing, and a port providing communication between a housing exterior and a housing interior between adjacent static seals. A method can include preventing leakage from a well with a seal assembly about a piston rod of a hydraulic actuator, the seal assembly including seal cartridges, each including a dynamic seal that sealingly engages the rod, and each including a static seal that sealingly engages a seal assembly housing, enabling communication through a housing sidewall to a housing interior between adjacent static seals, and reciprocably displacing the rod in response to pressure variations in the actuator.

A horizontal high-speed testing device for a spiral seal of a cone bit bearing is provided. The device comprises a shaft, a spiral sleeve and a cone. The spiral sleeve is in threaded connection to the cone. Sealing threads are provided on an inner diameter of the spiral sleeve. Both the spiral sleeve and the cone are sheathed on the shaft. By the testing device of the present invention, a spiral seal structure for a cone bit bearing is simulated, and the cone drives the spiral sleeve to rotate; the sand draining performance of the spiral seal can be tested in two ways, i.e., by measuring the time required to drain the sand-containing liquid and by measuring the weight of drained sand, so that the smooth production and application of spiral seal products can be assured.

A portable appliance testing apparatus includes a water tank and a pump configured to draw water from the water tank and pressurize the water within a piping assembly. The apparatus further includes a pressure regulator switch coupled to the piping assembly to enable control of the pump based on a pressure within the piping assembly. The apparatus also includes at least one appliance connector coupled to the piping assembly to enable attachment of an appliance thereto.

A sealing arrangement (100) for a shaft, including at least a first seal element (10a) arranged around the shaft (30); at least a second seal element (10b) arranged around the shaft (30); wherein the first (10a) and second (10b) seal element include adjustable seal elements, wherein the first (10a) and second (10b) seal element include, respectively, an outer shell (14a,14b) of elastic material and a hollow core (12a,12b), wherein the hollow core (12a,12b) of the first (10a) and/or the second (10b) seal element is pressurized with a fluid for an adjustable sealing effect.

A diagnostic method may determine the leak-tightness of at least one seal and/or one valve function in a braking system with at least two brake circuits, following completion of a braking action. The diagnostic method may be carried out at a pressure still present after the braking action in one or both braking circuits and/or in hydraulic line or a working chamber of a piston-cylinder system or at a lower pressure, or it may be carried out at a pressure of at most 30 bar.

A work machine that can detect abnormality such as a malfunction and wear and tear of each of hydraulic pumps including control equipment with high precision and that can reduce equipment cost is provided. A controller 9 according to the present invention includes a volumetric-transfer-efficiency-calculating section 94 that calculates a volumetric transfer efficiency .sub.C representing a transfer efficiency of hydraulic oil between a hydraulic cylinder 11 and hydraulic pumps 21 to 23 on the basis of a target discharge flow rate calculated by a target-discharge-flow-rate-calculating section 932 and the speed of the hydraulic cylinder 11 that is detected by a speed sensor 28, and an abnormality decision section 95 that decides whether any one of the hydraulic pumps 21 to 23 is abnormal on the basis of the volumetric transfer efficiency .sub.C calculated by the volumetric-transfer-efficiency-calculating section 94.

There is disclosed a method of monitoring the health of an abradable seal located on a piston of an actuator, the method comprising the steps of: (i) measuring an initial velocity of said actuator piston while said actuator is maintained in a passive condition at an initial time; (ii) operating said actuator; (iii) measuring a subsequent velocity of said actuator piston while said actuator is maintained in a passive condition at a subsequent time; (iv) repeating steps (ii)-(iii) and either: recording or outputting the measured subsequent velocities over time; or determining a health status of said actuator when said subsequent velocity has increased above a predetermined amount.

One embodiment of the present invention relates to a sealing system having a leakage sensing function. A leakage sensing unit is arranged in a sealed space which is formed between sealing members of a sealing device body so as to sense, in real time, whether the sealing members are leaking, wherein a sensing value of the leakage sensing unit can be transmitted to the outside by using a communication unit.

A dual seal termination assembly having a first termination body; and a sleeve at least partially surrounding the first termination body; primary and secondary seals adapted to be fitted between the first termination body and the sleeve; a test port in the first termination body to supply test fluid to a point between the primary and secondary seals of the first termination body; the test port being adapted to receive test fluid at a predetermined pressure, such that a pressure difference is created between the point between the primary and secondary seals and a point on the other side of the primary seal and a point on the other side of the secondary seal.