The Flow Control Valve Called a Spool Valve

Complex control system of gas equipment
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A spool valve is a type of flow control valve that is part of a hydraulic or pneumatic system that controls or regulates the flow of fluid or compressed air in a system. The valve is made of cylindrical spools that slide or rotate which allows or stops the flow of liquid. The spool valve cylinder is inside a sealed outer case. 

A spool valve can be found in almost every industry that uses hydraulics – for fluids such as oil, fuel, or water – or pneumatics – using compressed air as the energy source.

How it functions

There are several chambers drilled through the sealed outer case. These are the “ports.” The function of the spool is to easily slide from one end to the other inside the sealed case and provide the function of opening or blocking the ports depending on the position of the spool, as needed.

Spool valve actuators

The actuator is what causes the spool to move. This can be done in different ways:

Using a manual lever or button.

As part of a more complex control system using a solenoid actuator.

Whatever the actuator method is used to control the spool valve, the actuators are simply pushing the spool to move inside the sealed case housing, allowing either the free flow or blocking of the port paths.

In the case of spool valves using solenoid actuators, there may be a solenoid at each end of the valve. In others, there can be a spring return so that if the solenoid is no longer pushing the actuator, the spring will return the spool to its rest or normal position.

Types of spool valves:

  • Sliding spool valve

These valves have a cross-section cylinder and their grooves and lands are cylindrical as well. Inside the valve, the spool itself is grooved and slides in and out of position inside the sleeve. This is to either block or open the intake or outtake portals for fluids or air. 

  • Rotary spool valves

The spheres in the lands and grooves in a rotary valve are in the form of holes. The rotary spool valve contains the fixed tubular sleeve, and inside is the rotating X-shaped core. The function of this valve is to act as a revolving door, with each bend of the core functioning as a closed or open portal.

MasterMac2000 P/L

In the Queensland and New South Wales areas, Master Mac 2000 is the sole distributor of Univer flow control valve and other pneumatic valves for mixed or spool systems. Univer’s high-quality products are suitable for all heavy and industrial applications. For more information or enquiries, call us on 07 3344 4711 or visit

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