A ride control valve includes a valve body defining a work passage, a pump passage, a tank passage, and an accumulator passage configure to couple to an accumulator. A ride control spool is movably disposed within the valve body and configured to move between a a first ride control position to discharge the accumulator, a second ride control position configured to charge the accumulator at a variable charge rate, a third ride control configured to balance the accumulator pressure with the work passage pressure, and a fourth ride control position configured to couple the accumulator to the work passage. A pressure balancing spool is movably disposed within the ride control spool to selectively couple the accumulator passage with each of the pump passage and the tank passage to balance the accumulator pressure. The ride control valve is configured couple to a directional control valve without external conduit.

A system for controlling a rotation of one or more solar panels about an axis of rotation, comprising one or more solar panels defining a longitudinal axis, one or more bellows actuators coupled to the one or more solar panels and defining an axis of rotation parallel to the longitudinal axis of the panels, a fluid source, a first valve circuit coupled to the bellows actuators and the fluid source, a second valve circuit coupled to the bellows actuators and the fluid source, and a controller, wherein introduction or release of fluid from one or more of the bellows actuators is configured to cause rotation of the one or more actuators about the axis of rotation.

An actuator that includes a bottom plate, a top-plate, and a first and second hub assembly extending between the bottom and top plates. The actuator can further include a first and second bellows disposed on opposing sides of the hub assemblies, the first and second bellows each extending between and coupled to the top plate and bottom plate. The actuator can also include a plurality of washers disposed between the top and bottom plates, with each of the washers coupled to the first and second hub assembly, a first set of the plurality of washers surrounding the first bellows and a second set of the plurality of washers surrounding the second bellows.

A turbine speed probe diagnostic system is provided. The turbine includes a speed probe and a speed reading circuit. A speed lead connects the speed probe and speed reading circuit together to transmit speed signals from the speed probe to the speed reading circuit. A speed probe diagnostic circuit is also provided for connection to the speed lead. An isolation switch is provided to isolate the speed probe diagnostic circuit during normal operation when the speed reading circuit is receiving speed signals from the speed probe. When no speed signals are being received, the isolation switch closes and the speed probe diagnostic circuit performs a test on the speed probe or speed lead.

A control system is provided for a turbine valve. The turbine valve has a first coil and a second coil to control or sense movement of a mechanical valve positioner. Two valve positioners are provided with each valve positioner having two drive circuits to drive the first and second coils. Switches are provided such that only one drive circuit is connected to each coil at a time. The control system may also include a hydraulic pilot valve section and a main hydraulic valve section. Feedbacks are used to determine a pilot valve error and a main valve error which are combined to determine a turbine valve error. The turbine valve error is repeatedly determined to minimize the error.

A turbine control system is provided for decreasing the response time between readings of the speed of the turbine and changing a valve position in response thereto. The speed control system includes a speed probe that detects the speed of the turbine and a turbine valve that controls the flow of fluid or gas from or to the turbine. A controller receives a speed signal from the speed probe and sends valve position commands to the turbine valve. The controller also sends support functions to the turbine valve. The controller sends the valve position commands at a faster rate than the support functions.

A speed control system and a power load balance detector for a turbine is provided. The speed control system includes a speed wheel with a plurality of teeth. A timer stores a time stamp when each of the teeth passes by a speed probe. A first speed estimate is determined for overspeed protection, and a second speed estimate is determined for operational speed control. The power load balance detector trips or shuts down the turbine when an unbalance is above a first threshold and the speed of the turbine is above a second threshold.

A breaker between two electrical circuits is provided that is closed when electrical properties in both of the electrical circuits are matching. Two check circuits are provided for comparing electrical properties of the two electrical circuits. Each of the check circuits sets a corresponding authorization to close the breaker. The breaker is only closed if both check circuits set an authorization to close the circuit.

A pneumatic control unit configured to inflate a first and second set of bellows with fluid from a pneumatic fluid source via a pneumatic circuit, the first and second set of bellows associated with one or more pneumatic actuators. The pneumatic control unit determines a target configuration of the actuators based on a determined current position of the sun; determines a current configuration of the actuators; determines a difference between the determined current configuration and target configuration of the actuators; determines that the difference between current configuration and the target configuration of the actuators is outside of a tolerance range; and actuates the actuators toward the determined target configuration by at least one of inflating the first or second set of bellows with fluid from the pneumatic fluid source via the pneumatic circuit.

An embodiment of the present disclosure a dental chair a chair assembly configured to support a patient. The dental chair also includes a traverse motion assembly coupled to the chair assembly that move the chair assembly in a forward-backward direction. The dental chair also includes a sensor assembly having a rod rotatably fixed to the traverse motion assembly. The rod defines a first end, a second end opposite the first end, and a rod cross-sectional shape. The dental chair also includes a sensor assembly is configured to obtain data indicative a distance of linear movement of the chair assembly along the forward-backward direction between.