Types of Valves Used in Pneumatic Automation.

As we now know that actuators are the components which performs the work and we are aware with types of actuators, and we also know about the supply elements used in pneumatic automation.


To get a desired motion we need to feed the air at certain pressure and control the direction of flow. This is where role of valves come into action. The valves in pneumatic system is used to regulate and modulate the air pressure according to the need. They work as switch, control units and sometimes operate the sensors.


Let us see types of valves used in a pneumatic system.


1. Directional Valve-


As name signifies directional valves are used to give direction to the flow or we can say it permits the fluid to flow on decided route. Directional Valves are the most fundamental valve used in hydraulic or pneumatic system, These valves contents spools in a cylinder which restricts of permits the flow depending on it's position. Remember the spool can move but the cylinder is fixed. On basis of mode of operation these valves are divided in three parts.



Fig. 1: Group of Directional Valves

i) Mechanically Operated- In this valves the movement of spool occurs due to a mechanical action, it can be due to push button, a lever or due to any mechanical sensing arrangement.







Fig. 2: Section of Pneumatic Directional Valve

ii) Pneumatically Operated- These valves are operated with the help of air pressure only. When a required amount of air pressure is given to the valve it shifts the spool and allow the flow or restricts it, depending upon the design.

We can also set the amount of pressure required to move the spool using an arrangement of sensors.


iii) Solenoid Valve- These valves are used when we need to automate the process. The key components of a solenoid valve are plunger, coil and sleeve assembly. When with the help of electric signal energizes it produces magnetic field which moves the plunger allowing the flow or restricting it depending on if the valve is normally open or normally closed type.



2. Flow Control Valve-


Flow control valve are used to control the flow by reducing or increasing the rate of flow and directing them according to need, These valves controls the flow on the basis of signals they receive from the sensors like flow meter or temperature gauges.



Fig 3. A simple Flow Control Valve

Types of Flow control valves.

  • Throttle Valve

  • Two pressure valve

  • Shuttle valve

  • Quick exhaust valve

  • Timers

  • Nozzles

  • Orifice

  • Check valve

  • Pneumatic counter.

These are some mainly used valve in a cinematic circuit.


3. Pressure Control Valve


These valves groups are used in a pneumatic circuit to determine the pressure at certain point in the system as per the need or working capacity of the device we are using. Also these valves helps to keep the pressure within the safety limits.



Fig. 4: A Pressure Control Valve with Pressure Regulator

Types of pressure control valve.

  • Pressure control valve with manometer

  • Pressure reduction valve

  • Variable pressure reducing valve

  • Pressure compensator

These are some of the pressure control valves we use widely. There are various sensors which we use to operate these valves and automate the system we will know about them in next blog.

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