2/2 Coax Pneumatic Valve

2/2 way coax pneumatic valve range.

Pneumatically operated or external pilot air controlled 2/2 way coaxial valves are available across a 2/2 coax pneumatic valvewide range of port sizes, port thread or flange type, orifice size, pressure range, body materials, seal material and function to provide the best cost effective solution to match the application at hand.

Below are example of the more popular 2/2 air actuated coaxial valves, all have options for normally closed or normally open. Stated maximum pressures shown are according to maximum inlet pressure however coaxial valve can handle back pressures at reduced rates typically 16 bar maximum, except model 286 that is 100% leak tight up to 40 bar back pressure.

You can view a typical technical data sheet here...

Basic Principle

How 2/2 coaxial pneumatic valves work.

Valve working basics.

2/2 Pneumatic coaxial valve normally closed

2/2 normally closed coaxial pneumatic valve

Pressure: Flow P to A maximum pressure

Flow A to P 16 Bar

2/2 Pneumatic coaxial valve normally closed

Fail-safe Closed - No Flow

2/2 Pneumatic coaxial valve normally closed - actuated open

Actuated Open - Full Flow

 

2/2 Pneumatic coaxial valve normally open

2/2 normally open coaxial pneumatic valve

Pressure: Flow P to A maximum pressure

Flow A to P 16 Bar

2/2 Pneumatic coaxial valve normally open

Fail safe Open - Full Flow

2/2 Pneumatic coaxial valve normally open - actuated closed

Actuated Closed - No Flow

Normally Closed Solenoid

How a Coaxial 2/2 way normally closed pneumatic valve works.

symbol for 2/2 way normally closed pilot

2/2 way normally closed air pilot symbol

The coaxial valve is in the fail-safe closed state.

This externally controlled pneumatic valve is in the rest failure position, the control tube (2) through which the medium (blue) flows is pressed by a compression spring (3) against the seal of the valve seat (1). The valve is thus permanently closed.

If the valve is pilot operated by a 5/2 Way Pilot control valve, the control tube is pressed in addition to the spring, by means of control air (green) at port 2 into the seat. Port 4 is exhausted to atmosphere.

2/2 way normally closed coax valve - closed position

The coaxial valve is in the actuated open state.

By supplying the control air at the port 4, the space in the cylinder is set under pressure, which pushes the control tube (2) in the axial direction away from the valve seat (1) and so releases the passage allowing flow. The space at port 2 is exhausted to atmosphere. Due to this shift in the valve tube, a compression spring (3) is compressed further.


When port 4 is vented to atmosphere, the compression spring (3) pushes the control tube (2) back to its initial position against the valve seat (1). The valve is then closed again - no flow.

2/2 way normally closed coax valve - open position

Normally Open Function

How a Coaxial 2/2 way normally open pneumatic valve works.

symbol for 2/2 way normally open pilot2/2 way normally open pilot symbol

The coaxial valve is in the fail safe open state.

When the NO valves is in the rest position, the control tube (2) through which the medium (blue) flows, is pressed by a compression spring (3), to the left and results in an open passage for flow of media. The valve is thus permanently opened.

If the valve is pilot operated by a 5/2 Way Pilot valve, the control tube is pressed away in addition to the spring, by means of control air (green) on port 4 from this valve. The space at port 2 is exhausted to atmosphere.

2/2 way normally open coax valve - open position

The coaxial valve is in the energised closed state.

If the space in the cylinder is filled through the port 4 with the control air (green), the control tube (2) moves in the axial direction towards the sealing of the valve seat (1), thus closing the passageway. The space at port 2 is vented to atmosphere. Due to this shift in the valve, the compression spring (3) is compressed further.

When air is released or vented from the port 4, the compression spring (3) shifts th

Technical Data Sheets

Click on the links below for the full PDF technical data sheets.
ModelPressure (Bar)Port SizesPort TypeOrifice Sizes (mm)Body MaterialSealing
280 64 1/4, 3/8, 1/2, 3/4, 1, 11/4, 11/2, 2"

 BSP, NPT Thread or flange

10,15,20,25,32,40,50 Brass, AISI303 or 316 Stainless steel, Galvanised or nickel plated steel FKM,NBR,EPDM
280X 64 1/4, 3/8, 1/2, 3/4, 1, 11/4, 11/2, 2"  Manifold 10,15,20,25,32,40,50 Brass, AISI303 or 316 Stainless steel, Galvanised or nickel plated steel FKM,NBR,EPDM
281 120 1/4, 3/8, 1/2, 3/4, 1, 11/4, 11/2, 2"  BSP, NPT Thread or flange 10,15,20,25,32 Brass, AISI303 or 316 Stainless steel, Galvanised or nickel plated steel FKM,NBR,EPDM
281X 120 1/4, 3/8, 1/2, 3/4, 1, 11/4, 11/2", Modular System  Manifold 10,15,20,25,32 Brass, AISI303 or 316 Stainless steel, Galvanised or nickel plated steel FKM,NBR,EPDM
282 160 1/4, 3/8, 1/2, 3/4, 1, 11/4"  BSP, NPT Thread or flange 10,15,20,25 Brass, AISI303 or 316 Stainless steel, Galvanised or nickel plated steel FKM,NBR,EPDM
282X 160 1/4, 3/8, 1/2, 3/4, 1 and 11/4", Modular System  Manifold 10,15,20,25 Brass, AISI303 or 316 Stainless steel, Galvanised or nickel plated steel FKM,NBR,EPDM
283 200 3/8, 1/2, 3/4  BSP, NPT Thread or flange 15 Brass, AISI303 or 316 Stainless steel FKM,NBR,EPDM
283X 200 3/8, 1/2, 3/4, Modular system  Manifold 15 Brass, AISI303 or 316 Stainless steel FKM,NBR,EPDM
286 40 3/8   8 Brass FKM,NBR,EPDM
286X 40 3/8  Manifold 8 Brass FKM,NBR,EPDM

2/2 Coaxial air valve orifice sizes and flow rates.

Coax air operated valves are available with a wide range of orifice sizes offering users a choice of various flow rate coefficients for each port connection size. This orifice or internal flow path diameter relates to an internal tube of flow path diameter, so the larger the tube the higher the flow rate through the coaxial valve although there are some limitations. These limits relate the limitations of the port or connection size as having a larger internal tube orifice with a smaller connecting port the flow will be limited by the smaller port size, which is therefore uneconomical and an expensive mistake as the valve body increases in size and cost in relation to the orifice size too. The bonus here is that manufacturers will not typically supply coaxial valves outside the parameters of sound engineering practise and would probably not have designed any irrational options anyway. Another useful point is that for each orifice size typically a range of port sizes will be available for the same price, so for example a 1" BSP port may be available with 15mm, 20mm and 25mm internal tube diameters or orifice sizes offering different flow rates, valve dimensions and of course prices.

2/2 coaxial valve air pilot controllers.

Air pilot control valves or Namur mount solenoid valves are designed to bolt directly onto any air operated coax valve body that has namur interface offering an electrical control of the compressed air supply to open and or close the main air actuated valve. The two ports with the O ring seals will line up and seal against a namur interface valve, with bolts Namur mount solenoid control valvesto secure this valve in place. Typically a compressed air supply is connected to the central air inlet port of the solenoid valve (see picture on right centre port of the three visible ports on the side), the other two ports either side are the exhaust ports.

These solenoid control valves are electrically actuated, require only a small amount of power typically 4.5 watts, are available across a broad range of voltages from 6vdc, 12vdc, 24vdc, 48vdc, 110vdc, 220vdc and 12vac, 24vac, 48vac, 110vac and 230vac either IP65 safe area or ATEX EEx mIIT4.

Valve Options

Coax pneumatic valves are available with a range of additional options to increase suitability for individual applications. Below we have detailed some of the more common options, however there is typically a vast additional range of custom options that most manufacturers can accommodate.

Mounting Brackets.

To secure the valve body into place.

mounting brackets
 Exhaust air throttle  exhaust air throttle
 Silencer  Silencer
Namur mount solenoid valve controller  namur mount solenoid valve