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The Axelson™ PA pneumatic surface safety shutdown gate valve automatically performs fail-safe during a predetermined emergency condition, a control pressure loss, or a mechanical seal failure within the device. This fail-safe function may involve closing or opening the valve depending on customer requirements.
This versatility of function enables the PA valve to be used as a safety shutdown valve, a diverter valve, or a blowdown valve. The Axelson PA automatic valve meets the requirements of ANSI B16.34 and API 6D Specifications. It was developed to replace power-operated gate valves, ball valves, butterfly valves, globe valves, and plug valves on installation when the fail-safe function is desired to protect personnel, the installation, and the environment.
The unit may also be adapted with a manual hand-wheel to override the automatic function. Other accessories include heat-sensitive lock-open caps and hydraulic overrides.
- Versatile – Our PA automatic gate valves are manufactured to ANSI B16-34 and API 6D Specifications for use on installations requiring automatic fail-safe safety shutdown, blowdown, or diverter valves. The PA automatic gate valve does not require an external power source to close (or open depending on application) in case of an emergency involving a power failure.
- Control pressures – Dependent on valve bore size, valve body pressure, and actuator size (see recommended control pressures chart)
- Unique seat design – A unique free-floating gate and seat design provides a means of maintaining body pressure while retaining bidirectional capabilities. The gate and seat design permits bidirectional pressure-sensitive sealing, reduces the effect of erosion, and diminishes the possibility of pressure lock.
- Temperature ranges – -20 to 250 °F (-29 to 121 °C)
- Metal-to-metal seals – Located at the point of bonnet-to-body contact with a backup elastomer seal and at the bonnet-to-stem contact
- Seals without lubrication – No lubrication is required to ensure gate and seats seal. Fittings are provided to lubricate the packing.
- Open/closed indication – The position of the upper shaft indicates the position of the gate as it moves up or down with the diaphragm.
- Corrosion resistance – The lower shafts, stems, gates, and seats are manufactured of corrosion-resistant materials.
- Accessories – Manual override provides manual operation of the valve. Fusible manual override caps, hydraulic overrides, and adjustable fusible lock-open caps are also available.
- Fail-safe – the automatic fail-safe function shuts down a system in response to a programmed signal, predetermined emergency conditions, control pressure loss, or mechanical seal failure within the device (fail-safe open options are also available).
- Diaphragm actuator – use of a diaphragm actuator versus a piston actuator provides a seal that is not affected by corrosion, galling, or pitting of a metal surface such as the inside diameter of the piston housing. the nylon-reinforced diaphragm does not require lubrication and will not wear due to friction or misalignment between the piston and housing. there is no o-ring to twist out of shape or to be affected by swelling of the elastomer.
- Lightweight – the diaphragm actuator on the valve is very light and can easily be removed by one person without special tools or external pressure sources.