Abstract: A fuel cell system is provided that includes a fuel cell with an assembly of multiple individual cells, each of which has an anode section, an electrolyte membrane, and a cathode section, an anode gas supply, which leads to an anode gas inlet and includes a fuel cell and a fuel metering device, a cathode gas supply, and a passive anode gas recirculation device, which connects an anode gas outlet to the recirculation gas inlet of a mixer arranged in the anode gas supply. The fuel cell system is started up after a standstill in that in a first phase, the fuel cell is activated while fuel is supplied from the fuel source, and the anode recirculation is suppressed without actively blocking the anode gas recirculation device, and in a second phase, anode gas is recirculated in addition to the supply of fuel from the fuel source.

Abstract: A fuel cell system is provided having a fuel cell and a jet pump control valve unit connected to an anode chamber with an intake connection and a pressure connection. A fuel gas control valve connecting a fuel gas source and the jet pump has a valve seat with a first sealing surface and at least two through-flow channels, and a moveable valve body with a second sealing surface. The valve body can be moved into a blocking position and a through-flow position using a valve body actuator. The sealing surfaces rest on one another in a common sealing plane and form a seal in the blocking position. A stroke gap is formed between the sealing surfaces in the through-flow position. The first or second sealing surface is arranged on a raised sealing level. A volume flow of a drive jet can be controlled by the valve body actuator.

Abstract: A safety valve is provided with an electronic control unit for generating a control voltage. An electro-fluidic preliminary stage has a piezo bending actuator which can be actuated between a working position and a safety position by the control voltage and influences the flow of a secondary control fluid flow depending on its position. A fluid-mechanical main stage has an influencing device for influencing the flow of a primary working fluid flow. The influencing device can be actuated by means of the secondary control fluid flow which flows into a control chamber of the main stage. The control unit caries out a test of the preliminary stage repeatedly in an iterative manner after the expiration of a specified time interval. As part of the functionality test, the position of the piezo bending actuator is changed slightly by varying the control voltage.

Abstract: A safety valve is provided with an electronic control unit for generating a control voltage. An electro-fluidic preliminary stage has a piezo bending actuator which can be actuated between a working position and a safety position by the control voltage and influences the flow of a secondary control fluid flow depending on its position. A fluid-mechanical main stage has an influencing device for influencing the flow of a primary working fluid flow. The influencing device can be actuated by means of the secondary control fluid flow which flows into a control chamber of the main stage. The control unit caries out a test of the preliminary stage repeatedly in an iterative manner after the expiration of a specified time interval. As part of the functionality test, the position of the piezo bending actuator is changed slightly by varying the control voltage.

Abstract: A proportional valve is provided wherein the valve has an actuating element, a compressed-air connection, a working connection, and an air-removal connection. The valve also has three valve elements arranged one after the other and each can be moved in an axial direction. A first valve element is actuated by the actuating element, a second valve element is actuated by the first valve element, and a third valve element is actuated by the second valve element. In a base position, the valve elements are spaced apart, and, within the valve, a first sealing seat effective between the first valve element and the second valve element and a second sealing seat effective between the third valve element and the housing are arranged such that by varying the position of the first valve element, different switching states can be set.

Abstract: An electropneumatic valve assembly comprises an electropneumatic pilot stage and a pneumatic power stage which is actuated by the pilot stage. Each pilot valve switches at least two power valves, and the valve assembly has a housing with an electrical signal input, with a compressed-air port, at least one vent port and at least one working outlet. The housing is layered with a pilot stage housing and a power stage housing connected along a substantially planar parting surface. At least one sealing element is between the pilot stage housing and power stage housing surrounding a control pressure region between the pilot stage housing and power stage housing. The control pressure region has two actuation regions for two power valves and has a duct-like connection with a defined flow cross section between the two actuation regions. An outlet of the associated pilot valve opens into the control pressure region.

Abstract: A proportional valve is provided having a pilot control valve that can be controlled by means of a control signal and having a booster valve that can be actuated by means of the pilot control valve. The proportional valve has a compressed-air connection for connecting a compressed-air supply, a working connection, and an air-removal connection. The booster valve has three valve elements, which are arranged one after the other and can each be moved in an axial direction against a spring force.

Abstract: An electropneumatic valve assembly comprises an electropneumatic pilot stage and a pneumatic power stage which is actuated by the pilot stage. Each pilot valve switches at least two power valves, and the valve assembly has a housing with an electrical signal input, with a compressed-air port, at least one vent port and at least one working outlet. The housing is layered with a pilot stage housing and a power stage housing connected along a substantially planar parting surface. At least one sealing element is between the pilot stage housing and power stage housing surrounding a control pressure region between the pilot stage housing and power stage housing. The control pressure region has two actuation regions for two power valves and has a duct-like connection with a defined flow cross section between the two actuation regions. An outlet of the associated pilot valve opens into the control pressure region.

Abstract: A proportional valve is provided having a pilot control valve that can be controlled by means of a control signal and having a booster valve that can be actuated by means of the pilot control valve. The proportional valve has a compressed-air connection for connecting a compressed-air supply, a working connection, and an air-removal connection. The booster valve has three valve elements, which are arranged one after the other and can each be moved in an axial direction against a spring force.

Abstract: A proportional valve is provided wherein the valve has an actuating element, a compressed-air connection, a working connection, and an air-removal connection. The valve also has three valve elements arranged one after the other and each can be moved in an axial direction. A first valve element is actuated by the actuating element, a second valve element is actuated by the first valve element, and a third valve element is actuated by the second valve element. In a base position, the valve elements are spaced apart, and, within the valve, a first sealing seat effective between the first valve element and the second valve element and a second sealing seat effective between the third valve element and the housing are arranged such that by varying the position of the first valve element, different switching states can be set.

Abstract: The invention relates to a controlled three-way proportional valve unit comprising: a valve assembly with two individual valves; an actuating device actuating valves of the valve assembly; and a control unit acting upon the actuating device and having a control signal input, the valves of the valve assembly being designed as poppet valves arranged on opposite sides and having counter-rotatable valve spindles. The valve spindles are prestressed relative each other in opposite directions by a prestressing element such that, when the actuating unit is inactive, a first poppet valve is open and the second poppet valve is closed. The actuating device comprises an actuator common to both poppet valves, acts upon the two valve spindles and changes the position of the valve spindles counter to the effect of the prestressing element.

Abstract: A machine press is provided in which at least one hermetically sealed hydraulic drive unit is switchable from a working mode, in which a base pressure above ambient pressure is continually exceeded, into a rest mode. To this end, in parallel with a pressure converter, to the high-pressure side of which a pressure store and a raising working chamber of a cylinder piston unit are connected, a bypass is provided, having a first blocking valve that is controllable by a control unit and, in its blocking position, blocks the through-flow direction from the high-pressure side of the pressure converter to the low-pressure side. Furthermore, the low-pressure side is connectable to a lowering working chamber via a second blocking valve controllable by the control unit. The pressure output of the hydraulic unit is connectable to the raising working chamber via a third blocking valve controllable by the control unit.

Abstract: A drive unit is provided, particularly a drive unit for operating flow-control valves, comprising a housing, an electrical input, an electromechanical converter assembly, a mechanical output, and an electronic controller. The controller comprises an input unit having at least one pushbutton, which penetrates the housing and can be depressed against the action of a restoring device, and comprises a contactless switch that is actuated by the at least one pushbutton. A mechanical stop independent of the switch itself is associated with the position of the pushbutton that actuates the switch.

Abstract: A machine press is provided in which at least one hermetically sealed hydraulic drive unit is switchable from a working mode, in which a base pressure above ambient pressure is continually exceeded, into a rest mode. To this end, in parallel with a pressure converter, to the high-pressure side of which a pressure store and a raising working chamber of a cylinder piston unit are connected, a bypass is provided, having a first blocking valve that is controllable by a control unit and, in its blocking position, blocks the through-flow direction from the high-pressure side of the pressure converter to the low-pressure side. Furthermore, the low-pressure side is connectable to a lowering working chamber via a second blocking valve controllable by the control unit. The pressure output of the hydraulic unit is connectable to the raising working chamber via a third blocking valve controllable by the control unit.

Abstract: A drive unit is provided, particularly a drive unit for operating flow-control valves, comprising a housing, an electrical input, an electromechanical converter assembly, a mechanical output, and an electronic controller. The controller comprises an input unit having at least one pushbutton, which penetrates the housing and can be depressed against the action of a restoring device, and comprises a contactless switch that is actuated by the at least one pushbutton. A mechanical stop independent of the switch itself is associated with the position of the pushbutton that actuates the switch.

Abstract: The invention relates to a controlled three-way proportional valve unit comprising: a valve assembly with two individual valves; an actuating device actuating valves of the valve assembly; and a control unit acting upon the actuating device and having a control signal input, the valves of the valve assembly being designed as poppet valves arranged on opposite sides and having counter-rotatable valve spindles. The valve spindles are prestressed relative each other in opposite directions by a prestressing element such that, when the actuating unit is inactive, a first poppet valve is open and the second poppet valve is closed. The actuating device comprises an actuator common to both poppet valves, acts upon the two valve spindles and changes the position of the valve spindles counter to the effect of the prestressing element.

Abstract: A fluid-operated actuating drive on a valve comprising a base unit (2) having an electro-fluidic signal converter and a fluidic controller and at least one linear actuator (4) that can be actuated using the fluidic controller, wherein the gate (11) of the linear actuator is directly or indirectly coupled to the inlet of the valve. A control unit (22) is connected to a signal input of the base unit, wherein the signal output is connected to the electro-fluidic signal converter. The actual value signal of a measurement transducer (24) associated to the valve is fed back to the control unit. A fluidic internal control circuit (27) is arranged functionally between the signal input and the at least one linear actuator, preferably downstream of the electro-fluidic signal converter.

Abstract: A fluid-operated actuating drive (1) on a valve, in particular a shut-off, safety or regulating valve, comprising a base unit (2) having control valves, two linear actuators (6, 7) which are located opposite of each other and can be actuated fluidically, and a mechanical converter (5) which is arranged between the two linear actuators and couples the gates thereof to each other, wherein the outlet of the converter is coupled to the inlet of the valve. To this end, the actuating drive is composed in a modular manner of individual components joined to form a functional unit in the form of the base unit, the two linear actuators and the mechanical converter.

Abstract: A fluid-operated actuating drive (1) on a valve, in particular a shut-off, safety or regulating valve, comprising a base unit (2) having control valves, two linear actuators (6, 7) which are located opposite of each other and can be actuated fluidically, and a mechanical converter (5) which is arranged between the two linear actuators and couples the gates thereof to each other, wherein the outlet of the converter is coupled to the inlet of the valve. To this end, the actuating drive is composed in a modular manner of individual components joined to form a functional unit in the form of the base unit, the two linear actuators and the mechanical converter.

Abstract: A fluid-operated actuating drive on a valve comprising a base unit (2) having an electro-fluidic signal converter and a fluidic controller and at least one linear actuator (4) that can be actuated using the fluidic controller, wherein the gate (11) of the linear actuator is directly or indirectly coupled to the inlet of the valve. A control unit (22) is connected to a signal input of the base unit, wherein the signal output is connected to the electro-fluidic signal converter. The actual value signal of a measurement transducer (24) associated to the valve is fed back to the control unit. A fluidic internal control circuit (27) is arranged functionally between the signal input and the at least one linear actuator, preferably downstream of the electro-fluidic signal converter.