Tag Archive: proportional

What is a proportional control valve?

Proportional control valves provide variable hydraulic outputs proportional to an electric input signal in direction, flow or pressure. Electromagnetic output force of the solenoid is proportional to the current flowing through the coil.

Proportional control valves are used in a variety of applications to control the flow or pressure of fluids. Proportional valves are used in a variety of applications, such as controlling the flow or pressure of fluids. A proportional valve can be either directional or non-directional. Proportional valves are widely used in hydraulic systems and produce variable hydraulic outputs proportional to an electric input signal in direction, flow or pressure. .In hydraulic systems, a proportional valve consists of an actuator and a two-port or three-port valve.

A proportional valve is a valve that regulates the flow of fluid based on some input signal. A proportional valve consists of an actuator and a two-port or three-port valve. The actuator is usually a piston or diaphragm with a rod attached to it. The rod is connected to the stem at one end and pivots in the center of the two-port or three-port.

A proportional control valve is a type of valve that can be used to control the flow of a fluid by using an electric input signal. The electric current is converted into a magnetic field which interacts with the coiled wire in the valve, which in turn changes the flow and pressure of the fluid. There are many different types of proportional valves, but they all function in this same way.

Part 2. Proportional control in the regeneration mode.

Fig.1. Regeneration mode schematic

The goal of the calculation is definition of a cylinder velocity at the current operating voltage at the valve’s solenoid.
For calculations we need to know: cylinder and valve parameters (take them from manufacturer catalog), values of forces at cylinder rod (load) and pressure drop at return line (can be assumed as zero if unknown).

Summary:
2.1. Regeneration mode schematic
2.2. Regeneration Mode: Cylinder extension calculation
2.2.1. Balance of forces at the cylinder
2.2.2. Spool lands ratio and pressure drops at the spool lands
2.2.3. Hydraulic cylinder extension. System pressure calculation
2.2.4. Flow through spool lands: max. and at current voltage
2.3. Hydraulic cylinder retraction calculation
2.4. Final words….

Proportional valve calculation

Calculations Notes:

• The formulas and algorithm of calculations you can find by this link.
• Pressure compensated pump with variable displacement is used as a source of pressure and flow.
• The spool lands work as orifices and have the same shape on both sides of the spool land.
• The same orifice coefficient (Cv) is used for both lands.

Part 1. Proportional control of double acting hydraulic cylinder.

Fig.1. Double acting cylinder control.

The goal of this calculation is a definition of a cylinder velocity at any percent of the operating control signal at the valve’s solenoid (voltage or amperage).
For calculations we need to know: cylinder and valve parameters (take them from manufacturer catalog), values of forces at the cylinder rod (load), and pressure drop at the return line (can be assumed as zero if unknown).

Summary:
1.1. Hydraulic cylinder extension calculation.
1.1.1. Spool lands ratio.
1.1.2. Pressure drops at the spool lands
1.1.3. Balance of forces at the cylinder.
1.1.4. System pressure calculation.
1.1.5. Flow through spool lands: max. and at current voltage.
1.2. Hydraulic cylinder retraction calculation.
1.3. Full stroke time calculation.