Abstract:
The disclosure concerns a method for controlling the pressure in the chambers of a hydraulic cylinder (1) having a meter-out chamber (2) and a meter-in chamber (3). A meter-out valve (7) is connected to the meter-out chamber (2) for regulating the fluid out from the meter-out chamber (2) and a meter-in valve (8) is connected to the meter-in chamber (3) for regulating the fluid into the meter-in chamber (3). The method comprising the steps of sensing the pressure associated with the meter-out chamber (2) with a first pressure sensor (4) which is generating a first pressure signal, sensing the pressure associated with the meter-in chamber (3) with a second pressure sensor (5) which is generating a second pressure signal, processing the first pressure signal in a first signal processing filter (9) into a filtered first pressure signal, wherein in response to the filtered first pressure signal and a filtered or non-filtered second pressure signal delivering a control signal from a control unit (6) to the meter-out valve (7), and wherein the meter-out valve (7) in response to the control signal controls the pressure in the meter-in chamber (3) by regulating the fluid out from the meter-out chamber (2). The disclosure also relates to a corresponding system for controlling the pressure in the chambers of a hydraulic cylinder (1) having a meter-out chamber (2) and a meter-in chamber (3).
Abstract:
Methods and apparatus of stabilizing a valve positioner when testing a solenoid valve are disclosed. An example apparatus includes a solenoid valve (202) and a valve positioner (106) fluidly and communicatively coupled to the solenoid valve. The valve positioner is to be set in a pressure control state prior to conducting a test of the solenoid valve. The valve positioner is to detect a pressure change across the solenoid valve caused by the solenoid valve transitioning from a first state to a second state and transition the valve positioner from the pressure control state to a saturated state upon detecting the pressure change. The full supply pressure is to stabilize the valve positioner to conduct the test of the solenoid valve. The valve positioner is to maintain the saturated state until the pressure across the solenoid valve returns to the predetermined initial value.
Abstract:
Die Erfindung betrifft einen hydraulischen Antrieb für eine hydraulische Achse wie bei- spielsweise eine Ziehkissenvorrichtung einer Presse, mit einer Fluidpumpe zur Bereitstel- lung eines Volumenstroms für einen Ziehvorgang von einem Fluidvorrat zu einem Hydrau- likzylinder der Ziehkissenvorrichtung und von dem Hydraulikzylinder zu dem Fluidvorrat. Erfindungsgemäß ist vorgesehen, dass der hydraulische Antrieb eine Motorpumpenein- heit, eine Zirkulationsleitung und eine Ventilvorrichtung umfasst, wobei die Ventilvorrich- tung zwischen der Fluidpumpe und dem Hydraulikzylinder angeordnet ist und wobei über die Ventilvorrichtung ein Volumenstrom von der Fluidpumpe zu dem Hydraulikzylinder und/oder von dem Hydraulikzylinder zu der Fluidpumpe führbar ist und wobei über die Zirkulationsleitung ein Zirkulationsvolumenstrom mittels der Fluidpumpe von dem Fluid- vorrat zu der Fluidpumpe und von der Fluidpumpe zu dem Fluidvorrat zirkulierbar ist. Des Weiteren betrifft die Erfindung ein Verfahren zur Steuerung eines solchen hydrauli- schen Antriebs.
Abstract:
Methods of controlling an actuator 103 during operation using a hydraulic circuit, and related apparatus, are described. The circuit can comprise a first path section along which fluid is supplied to a first chamber 103a of the actuator using a first valve 110 and a second path section along which fluid is extracted from a second chamber 103b of the actuator using a second valve 111. In various embodiments, pressure data associated with a pressure of the fluid supplied to the first side of the actuator are obtained, a pilot pressure pPilot is produced based on the data and the first and second valves are configured based on the pilot pressure pPilot .
Abstract:
A method and system for controlling output torque of a fluid-actuated actuator connected to an input shaft of a movable device so as to control output force or torque of the actuator. The system and method involve determining first and second allowed pressures at all positions of travel of the actuator shaft when pressure is increasing and decreasing, respectively. In the method, the position of the actuator shaft is sensed and under the control of a PLC or similar controller, the pressure applied and/or exhausted from the actuator is controlled.
Abstract:
A safety and availability manifold system for a petroleum downstream complexes and petro-chemical industry is disclosed, the manifold system having at least one intake and at least one exhaust, the manifold system comprising' at least two automatic valves coupled to one another so as to form series and parallel redundancies and at least two manual operated valves corresponding to the two automatic valves that form series and parallel redundancies the manual operated valves being operatively coupled to an automatic valve in a hot swapping manner. The manifold system further includes at least one shuttle valve operatively coupled to the two automatic valves, an actuator with a rack and pinion arrangement connected to springs attached at opposite ends is operatively connected to the shuttle valve, one or more electrically-operated pressure sensors and one or more indicators that are electrically coupled to the two automatic valves to indicate an availability status thereof.
Abstract:
Bei einer Maschinenpresse ist mindestens eine hermetisch abgeschlossene hydraulische Antriebseinheit (2) aus einem Arbeitsmodus, in welchem innerhalb der hydraulischen Antriebseinheit (2) ständig und überall ein über dem Umgebungsdruck liegender Basisdruck überschritten wird, in einen Ruhemodus schaltbar. Hierzu besteht parallel zu einem Druckwandler (9), an dessen Hochdruckseite (H) ein Druckspeicher (8) und ein Heben-Arbeitsraum (10) einer Zylinder-Kolben-Einheit (3) angeschlossen sind, ein Bypass (12) mit einem von einer Steuereinheit steuerbaren, in seiner Sperrstellung zumindest die Durchflussrichtung von der Hochdruckseite (H) des Druckwandlers (9) zu dessen Niederdruckseite (N) sperrenden ersten Sperrventil (13). Weiterhin ist die Niederdruckseite (N) des Druckwandlers (9) über ein von der Steuereinheit steuerbares zweites Sperrventil (15) mit einem Senken-Arbeitsraum (11) verbindbar. Und der Druckausgang (16) des Hydraulikaggregats (7) ist über ein von der Steuereinheit steuerbares drittes Sperrventil (17) mit dem Heben-Arbeitsraum (10) verbindbar.
Abstract:
A hydraulic system and methods for conserving energy in such system is disclosed. The hydraulic system includes a hydraulic actuator having a head end, a rod end and a piston disposed therebetween. The system also includes a pump that pumps fluid to the actuator, a first valve disposed downstream of the rod end, and a second valve disposed between the pump and the head end of the actuator. When the system is in a load overrunning condition, the second valve is partially closed to restrict the flow of a combined fluid. The combined fluid including fluid received from the pump and fluid received from the rod end of the actuator. When the system is in the light resistive load condition, the second valve is open to allow the combined fluid to flow through the second valve.