Angle Seat Piston Valves
Air Actuated Angle Seat Piston Valves.
Air Operated angle set piston valves also known as Pneumatic Globe or Y pattern valves, offer very high flow due to their Y pattern design and are offer excellent on / off flow control for most gas and liquid applications, including contaminated, viscous and aggressive fluids and gases.
Function: 2/2 Normally Closed, optional Normally Open or Double Acting.
Pressure: 0 to 16 Bar (with flow over seat) or 0 to 8 Bar (with flow under seat for anti water hammer),
Operation: compressed air pilot 3 to 8 Bar
Port sizes: 3/8 up to 3" BSP thread, optional NPT thread or flange PN16, ANSI150Lb or JIS10K flange
Body & Internals: 316 Stainless Steel
Actuator head: 304 Stainless steel, option Plastic
Seals: PTFE, Option NBR or Viton
Media temperature: +200ºC Max
Media: suitable for steam, air, water, oil, steam. Gases, most acids or alkali and most liquids up to 600 centistokes that are compatible with 316 stainless steel and PTFE.
Duty cycle: exceeding 1,000,000+ operations,
Every unit is factory pressure function and leak tested for total trust in performance and reliability, offering the lowest total cost of ownership (TCO) compared to any other brand.
Options for Proximity Open switch, modulating control and mechanical open and closed position with LED and other custom-made options.
EC Declaration of Conformity according to European Directive 2014/68/EU ANNEX II (Module A2)
Pneumatic angle globe valves. (Normally Closed - Failsafe Closed)
Pneumatic angle globe valves. (Normally Open - Failsafe Open)
Open proximity and mechanical open and closed position feed back and modulating control
Manifold Systems
12 Reasons to use a pneumatic piston valve
Pneumatic piston valve, or air angle seat globe valve is a simple device that has become an industry standard type for controlling steam, water, oil, thick liquids, aggressive media and vacuum which is why is has become so popular and what makes it the valve of choice for high temperature applications and many other flow control applications where a solenoid valve is not ideally suited.
A) Saturated steam applications quite often reach temperatures up to +200 degrees Centigrade. At this temperature, many seals will be affected and eventually fail. A pneumatic piston valve will generally use PTFE (Teflon) as main seals to form a positive seal on the seat. PTFE has been proven to handle high temperatures up to 230 centigrade and provide good sealing and resistance to chemicals and abrasion. It is also common for steam to contain abrasive particles which could score a seal such as in a rotary ball valve causing leakage, whereas a valve utilising linear motion will avoid this risk. Valve castings manufactured from bronze (gun metal) and 316 stainless steel (CF8M) are also very durable and ideally suited to this type of heavy-duty application.
B) A pneumatic piston valve is fast acting compared to many other types of pneumatic valve, such as rotary ball or butterfly valve, either pneumatically driven or motor actuated. This is mainly due to the efficiency of the short linear action between open and closed position as opposed to rotation through 90 degrees and requires very little force to operate, hence its compact pneumatic cylinder (or actuator). Most air driven piston valves will operate in under 1 second.
C) Most models of piston valve are bidirectional and are able to control reverse flow (i.e. from outlet port to inlet port, albeit at a 50% reduced pressure range) heat and pressure will be under the seat which better isolates and protects the stem seals and reduces heat transfer into the actuator. Some better models will use high temperature FKM seals in the actuator head for increased service life. Another advantage of using the valve in reverse flow (i.e. flow under the seat) is that it will eliminate water-hammer which can be caused by fast acting valves in higher pressure high flow water systems.
D) A pneumatic piston valve is often a very good choice of valve to use with vacuum systems, some standard valves are suitable but often slightly modified versions are required. A ball valve will often draw in air as the vacuum pulls the stem seals downward, a piston valve does not suffer from this and with vacuum drawn from under the seat the vacuum itself will increase the sealing force between the seat and seal.
E) Compared to an equivalent sized actuated ball valve, the piston valve is much more of a compact design, enabling installation into tighter and constrained spaces. In most cases, the actuator can be rotated by 360 degrees so that the air connection port can be conveniently located and typically are a more cost-effective solution to air actuated or motor driven ball valves.
F) The actuator of a piston valve can contain a spring to provide either normally closed function (spring above actuator piston compressed air to lift open) or normally open operation (spring below actuator piston compressed air to push closed). If the spring is not installed, then the valve will give a double acting operation, i.e. requires compressed air to open and to close.
G) Piston valves are supplied with a wide range of port connections, from BSP or NPT threaded, butt and socket weld, clamp, flanged and manifold modular design.
H) Apart from the small turbulence effect across the seat, the flow rate of a piston valve is typically very high. When operated, the main piston is lifted out of the flow path and most piston valves to offer almost full uninterrupted flow when in the fully open position with negligible pressure drop.
I) When fitted with a positioner module, the piston valve makes for an excellent modulating flow control valve due to its quick linear operation. It is simple to adapt the modulating valve to suit each application, providing linear or exponential flow control utilising a 4 to 20 milliamp or 0 to 10 volt control signal.
J) An open position proximity switch can fit in place of the visual position indicator at the top of the actuator head. This volt free open position sensor switches then the actuator lifts into the open position and magnetically triggers the switch, i.e. non-contact, so a control panel can know the valve is in the open position.
K) Open and closed position feedback switches, an extension fitted in place of the visual position indicator at the top of the actuator head, that gives mechanical position open and closed volt free feedback. This is a mechanical link direct activated by the position of the valve stem for both the fully open and fully closed positions.
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