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Vacuum, Low/High Temperatures [Classic 21 Series] 2/2, 3/2, & 4/2 Functions, 1/4" to 1-1/2" Port Sizes



  • Poppet construction for high dirt tolerance
  • ROSS vacuum valves have larger orifices, allowing greater flow and easing the transport of air even though there is a small differential between the vacuum within the valve and atmospheric pressure outside the valve
  • Can be mounted close to actuator, reducing length of pipe to be pressurized/exhausted on each cycle
  • Internal/external pilot supply
  • Near zero leakage


The function of directional control valves is to control the direction of flow in a pneumatic circuit. These valves can regulate the airflow being capable of stopping, passing, and changing the direction of airflow. These three functions usually operate in combination with each other.


Directional control valves have multiple ports with the number dependent on the valve type. All these valves have an inlet and an outlet port while many also have an exhaust port. The 21 series is offered in 2/2, 3/2, and 4/2 valve functions with a port size range of ¼” to 1-1/2” in both NPT and G threads.


The poppet construction of the 21 Series enables high-flow, positive sealing, self-cleaning, and a strong dirt tolerance that delivers a long-life. This valve series is available in both solenoid and air pilot controlled options. Solenoids are offered in several AC and DC voltages along with multiple electrical options that include DIN, M12 and conduit with leads.


Fluorocarbon and Buna-N seal options enable these valves to be used in a wide range of lower or higher temperature applications.


Vacuum Service Valves 

Ideal for lifting, holding, vacuum packaging and moving anything from large objects to tiny particles. They also provide an effective means for leak testing. The vacuum source typically comes from either a vacuum pump or a venturi. In vacuum service applications, the pressure within the valve is reduced below atmospheric pressure. Consequently, atmospheric pressure actually pushes air into the valve, instead of the common belief that air is “sucked” in by the vacuum.


Full Vacuum Valves

Iideal for applications where compressed air is unavailable. Full vacuum valves use the difference in force between atmospheric pressure and the vacuum within the valve to actuate the valve. The full vacuum valve performs with atmospheric pressure in port 1 and 10 to 30 inches of Mercury vacuum in the valve body.


Please refer to the link on the left to easily view and download the ROSS Controls 21 Series Inline Poppet Valves with Increased Temperature Range product catalog for additional technical data. In addition, you can filter through all available options below to select the ideal valve that meets your requirements.