Flow and Pressure Control

An amplifier that consists of two fixed orifices, two variable orifices representing nozzles, flapper, and main valve simulated with mass, viscous friction, and centering spring. Two translational converters represent servo-actuators on both sides of the main valve. A feedback spring connects the flapper and the main valve.

A flow rectifier circuit, which consists of four check valves and a flow control valve. It is used to control flow rate flowing in both directions with only one flow control valve. Similar to a Graetz circuit implemented with diodes, the check valves are arranged in such a way that flow always passes through the flow control valve in the same direction. Two other check valves, Flow BA Check Valve and Flow AB Check Valve, are used to select an orifice depending on the flow direction.

Two valve actuators with different values for switching-on time and switching-off time. Valve Actuator 1 is set to start from the retracted position, while Valve Actuator 2 from the extended position. Both actuators are driven with the same pulse signal.

A use of a double-acting valve actuator. All three actuators are driven by the same pulse signals. A pulse is first applied to port A and after 1.5 s delay a pulse is applied to port B. Actuator A is set to start from the "Extended positive" position, while actuator C starts from the "Extended negative" position. As a result, actuators A and C move to the neutral position at the start of simulation and reach this position before the first pulse is applied. The actuators strokes, switch-on, and switch-off times are set to different values to illustrate the effects of these parameters.

A model of a two-stage servo-valve with a 4-way, 3-position spool valve in the power stage and a flapper-nozzle amplifier in the pilot stage. The flapper is connected to the armature of a torque motor, which in the example is represented with an ideal translational force source. The servo-valve shown in the example is equipped with the spring feedback between the flapper and the spool of the main valve. To investigate the behavior of such a valve, axial hydraulic forces on all four spool orifices are accounted for in the model by using Spool Orifice Hydraulic Force blocks. The servo-valve controls a simple double-acting cylinder in an open-loop application.

A simple way of modeling of the flow divider and using it with the load harness. The flow divider helps in dividing the input flow in desired percentage when the loads connected to the two lines are unequal. Flow divider allows flow only in forward direction. Therefore when it is used with the loads where unloading is done through reverse flows, then it should be used in conjunction with the direction control valves.

An actuator controlled by a 4-way directional valve and loaded with an overriding load, requiring the use of counterbalance valves to prevent the load from creeping when the directional valve is in the neutral position. In the neutral position, the directional valve connects ports A and B to the reservoir while blocking the pressure port P. The counterbalance valves block flow from returning to the reservoir, thus holding the actuator in place.

A pressure-compensated 3-way flow control valve. This valve maintains constant flow rate through the main hydraulic motor, which is connected to the pressure-compensated outlet of the flow control valve. It acts as a priority valve, diverting the excess flow to the auxiliary hydraulic motor if the main hydraulic motor receives enough fluid to maintain a preset angular velocity. The auxiliary motor is shut off completely if there is insufficient flow to power the main hydraulic motor.

A flow rectifier circuit with four check valves and a flow control valve. It is used to allow a single flow control valve to control fluid flow in both directions. Similar to a Graetz circuit implemented with diodes, the check valves are arranged in such a way that flow always passes through the flow control valve in the same direction. In the Orifices subsystem, there are two more check valves that are used to select the orifice that the flow passes through depending on the flow direction.

Parameterize and test a 4-way 3-position valve with a test harness. A plot script is provided with the example for comparing output flow between the block and data to verify the test harness. A live script is also provided with this example to explain the parameterization and the test harness workflow in detail.

Compares two 4-way directional valves, one with mechanical components to account for spool mass, valve spring and damper and one without (ideal valve). The input force to both valves is a sine wave. The operation of two valves are compared for different displacement frequencies, valve spring stiffness and damper coefficients.

Model, parameterize, and test a position control servo valve with a closed loop control. When you run the model, it generates a comparison plot between the commanded and the achieved position in the actuator with respect to the time. A position control servo valve provides a precise and fast control of the position in the actuator with a very small electrical signal to the torque motor. Aerospace, construction and agricultural equipments manufacturers use these valves for safety critical applications.

Model, parameterize, and test a pressure intensifier.

Model, parameterize, and test a pressure control solenoid valve. This example also generates a plot of the relationship between applied solenoid force and the resulting actuator port pressure.

Models a hydraulic system with a direct operated, pressure reducing valve. This system helps to limit and maintain pressure in a hydraulic punching machine. Pressure reducing valves are common in hydraulic pressing, drilling, and stamping applications.

Identify simulation slowdowns, resolve performance issues, and configure a Simscape Fluids™ model for real-time simulation. This example uses the Pressure Reducing Valve In Punching Operation model, PressureReducingValveInPunchingOperation which is called here as the original model. In this example, you measure the simulation time, identify the factors that affect simulation speed, optimize the model, and prepare the model for code generation.

Compares the mechanical performance of various spool actuation configurations and model fidelity levels for a hydraulic 4-way 3-position directional valve. The directional valve controls a simple double-acting cylinder in a closed-loop application. This example allows you to choose among four different spool actuation designs: