Solenoid Directional Control Valve Explained | Working of 5/2 DCV (Simple Guide)

In Industry; both the maintenance departments ‘Electrical’ & ‘Mechanical’ work Hand In Hand. Both the departments discuss troubleshoot if they have doubt in their minds.

As we are from Electrical Department, doesn’t mean that we don’t need to learn about mechanical part. It is beneficial for us when we have something extra As famous quote “The more we know; the better we become !”

In today’s modern era, pneumatic system & hydraulic system play a very important role. Maximum part of these systems is mechanical But these systems are so powerful & reliable. In fact, maximum machines are running with these two systems. That’s why it is important; we should know about hydraulics & pneumatic systems.

” ‘Hydraulics & pneumatics’ Both the systems are branch of Engineering which uses the power of fluid flow. In hydraulics, hydraulic oil is used as fluid on the other hand in pneumatic system, compressed gas or compressed air is being used. “

• What is a solenoid directional control valve

• Types and configurations (5/2 valve)

• Construction and parts

• Working principle of a 5/2 solenoid valve

• Practical industrial specifications, advantages, applications & troubleshoot

Before proceeding to directional control valve we should know about the pneumatic cylinder first !

WHAT IS PNEUMATIC CYLINDER ?

Pneumatic cylinders are used to obtain the linear shaft movement. These cylinders have piston in it which is been fitted on a piston rod. At both the outer end of cylinder, Pipe connector(socket) is provided for air connections. Piston & joints contains rubber seal so that no air leakage takes place.

When a rated air pressure from base pipe connector(socket) is applied, The air pressure pushes the piston outward. Similar the case, when an air pressure is applied  on another connector(socket) of cylinder it pushes the piston Inward.

By controlling the pressure on both the end connectors(socket), A linear piston movement of pneumatic cylinder movement can be controlled As shown in image below:

NOTE: In whole process of movement, one big thing needs to be understand that Whenever we apply air pressure from one of the side, The free air is always present on another side of piston which do not allow piston to move freely until this free air allowed to pass easily.

For Cylinder movement, 2 things should be considered :

1. Rated air pressure at one of the air connector(socket).
2. At that same time, another air connector(socket) should be blockade free so that free air passes out easily.

Directional control valves performs Both the above said tasks !

DIRECTIONAL CONTROL VALVE

Directional Control Valve As name suggests, It is the device that control the ‘ENTERY’ & ‘EXIT’ of compressed air. These valves have multiple holes in it; In which some holes are Air Inlet-Outlet while some are air exhaust. There are many types of DCVs which operates with different methods & these methods known as Actuation.

• Valves which are physically operated by hand known as Manual actuation valve.
• Some valves are operated through air pressure known as Pneumatic actuation valve.
• Valves which are operated through solenoid coil are known as Solenoid actuation valve.

SOLENOID ACTUATED PNEUMATIC DIRECTIONAL CONTROL VALVE

In automation system, DCVs based on Solenoid actuation been used. These DCVs operates through an Electrical solenoid coil while solenoid coil energizes & controlled by PLC system.

These solenoids are available in both AC & DC voltages.

AC(50/60Hz)_ 24,48,110,230

DC___12,24,48,110

These DCV’s are categorized with two numbers. For example- 2/2, 3/2, 4/2, 5/2, 5/3.

The first number represents Holes present in valve & the second number represents the states of the valve.

• 2/2 valve: This valve has 2 Holes. 1one hole for air Inlet & another hole for air outlet. This valve has 2 states ‘Open & Close’.
• 5/3 valve: This valve has total five holes. 1 hole for air inlet, 2 holes for outlet & 2 holes for Exhaust. This valve has 3 states in which 2 states for 2 outlet holes while 1 state is neutral state like closed valve.

There are many types of valve like 2/2, 3/2, 4/2,5/2 & 5/3. Every single valve has same working mechanism with little changes in them. We can’t explain all type of valve in single post so we have taken one valve for explanation that is  5/2 Valve by Janatics pneumatic.

5/2 Valve by JANATICS PNEUMATIC

• MODEL: DS255SS61
• TYPE: 5/2
• WORKING PRESSURE: 2-10Bar
• PILOT PRESSURE: 2-4Bar
• AMBIENT TEMPERATURE: 5°C to 60°C
• AIR FLOW: 1200lts/min
• MATERIAL OF CONSTRUCTION: Aluminum, Nitrile, Stainless Steel, Brass, Acetal
• DUTY CYCLE: Continuous
• CLASS OF INSULATION: Class F
• COIL PROTECTION: IP65

Configuration of 5/2 solenoid Valve by Janatics pneumatic

This valve has 5 holes In which one is inlet, two outlets & two exhausts. Solenoid coil’s voltage is 230VAC. DCV’s main part is aluminum block which contains multiple holes in it. These holes are arranged in special symmetry which are provided for ‘ENTERY & EXIT’ of air. Solenoid coil is tightened on a hollow metallic shaft. For coil connection power plug is provided as shown in images below :

Generally, DCV’s are spool designed, A metallic spool carrying multiple rubber seals moves inside the cylindrical hole of aluminum block. Although these rubber seals on spool are also arranged in special symmetry. Shown in an image below :

The movement of spool inside cylindrical hole makes the ports of aluminum block ‘Open & Close’. Apart from Inlet-Outlet holes, Pilot hole is also provided. (This pilot hole; we will explain later) First let’s understand some of the parts of DCV.

LIFTER KNOB

For the manual actuation of DCV; A LIFTER KNOB has been provided. To actuate the valve for just a moment; press the knob. To actuate the valve permanently; press the knob & rotate in clockwise direction. To deactivate the valve, move the lifter knob in anticlockwise direction.

WORKING OF SOLENOID DCV

1. According to STATE1 Diagram when Left side coil energizes, 1(INLET) gets connected to 4(OUTLET) along with 2(OUTLET) gets connected to 3(EXHAUST). Entire Inlet pressure get available at PORT4 & PORT2 work as a exhaust which allows free air present in cylinder to pass.
2. According to STATE2 Diagram when right side coil energizes, 1(INLET) gets connected to 2(OUTLET) along with 4(OUTLET) gets connected to 5(EXHAUST). Entire Inlet pressure get available at PORT2 & PORT4 work as a exhaust which allows to pass the free air present in the cylinder.

The metal pin again retain its normal position with the help of spring fitted across it; when solenoid de-energizes. Whereas, plastic piston remains in forward position that’s why spool continue maintains its position even after solenoid de-energizes.

NOW, when another side of solenoid energizes. The whole process; metal pin movement, pilot hole opening, piston movement remains the same as explained above which results spool now moves in opposite direction. While spool moving in opposite direction; spool itself pushes the opposite side plastic piston back.

The free air present at the back of piston moves through metal pin cut outs through hollow metallic shaft & at last exit through the Nut holes.

Advantages of solenoid DCV

• Fast and automatic operation

• Can be controlled by PLC

• Suitable for remote operation

• Reliable and long service life

• Low maintenance

Applications of solenoid DCV

• Packaging machines

• Material handling systems

• Pneumatic presses

• Pick and place robots

• Automation lines

Troubleshooting

• Valve not shifting → Check coil voltage

• Air leakage → Check seals/spool

• Cylinder not moving → Check pressure and exhaust blockage

• Coil heating → Check continuous duty rating

FAQ for solenoid DCV

Q1. What is a 5/2 solenoid valve?
A 5/2 valve has 5 ports and 2 positions used to control double-acting pneumatic cylinders.

Q2. What voltage is used for solenoid valves?
Common voltages are 24V DC, 48V DC, 110V AC, and 230V AC.

Q3. What is the function of a directional control valve?
It controls the entry and exit of compressed air to change the direction of cylinder movement.

Q4. Can a solenoid valve work without air pressure?
No, pneumatic DCVs require minimum air pressure for proper operation.

Q5. Why is a silencer used in DCV?
To reduce noise from exhaust air.

SUMMARY

This post discusses the solenoid actuated pneumatic directional control valve (DCV) by Janatics Pneumatic, elaborating on its specifications, operation, and configuration. The DCV controls compressed air entry and exit, allowing for efficient pneumatic cylinder movement. It features different actuation methods, notably solenoid actuation, with specific models providing various functionalities. The working principle involves controlling pilot pressure to manipulate the spool within the valve for optimal air flow management.

Hope! You like the post. If you have any doubt, suggestion or query please do comments.