AS-Schneider Gauge Protectors are used to protect pressure-sensing instruments against damage, loss of accuracy, and/or rupture in the event of excessive system pressure. The piston assembly works against an adjustable spring. The piston assembly contains a sealing mechanism to isolate system pressure from the instrument. The Inlet to Outlet seal is an O-Ring, the sealing to atmosphere is realized by either another O-Ring (system pressures of more than 2 bar/29 psi) or a diaphragm (for system pressures 0.4 up to 2.5 bar/5.8 up to 36.3 psi). As system pressure overcomes the force of the spring, the piston moves, causing the sealing system to close. The outlet side is now isolated from increasing system pressure and the instrument is protected. As system pressure drops to the reopening pressure (25% below the closing pressure), the valve opens again. The max. allowable (Working) Pressure (PS) is 600 bar (8,702 psi), the max. allowable Temperature (TS) is 80°C (176°F), resp. 60°C (140°F) for our DVGW approved types S005.50.001.00DV / 201.00DV.
 Datasheet |
Overpressure Protection Devices by Armaturenfabrik Franz Schneider GmbH + Co. KG
Overpressure protection devices from Armaturenfabrik Franz Schneider GmbH + Co. KG are engineered components designed to safeguard pressure measuring instruments such as gauges, differential pressure gauges or pressure transmitters from excessive pressure. These devices are installed ahead of the instrument in the measurement line and act to intercept or limit pressure spikes, protecting the instrument and enabling reliable measurement performance.
By using overpressure protection devices, the operational life and accuracy of pressure measurement points are improved. They are available in various designs, connection types and pressure ranges to suit a wide range of industrial applications and process conditions.
Frequently Asked Questions about Overpressure Protection Devices
What is an overpressure protection device?
An overpressure protection device is a component installed between the process line and the pressure measuring instrument to prevent excessive pressure from reaching and potentially damaging the instrument.
Where are these devices used?
They are used wherever pressure spikes, surge loads or unexpected pressure excursions can occur in a process, and instrument protection is required.
How does an overpressure protection device work?
It intervenes when the pressure exceeds a defined protection threshold, reducing or damping the pressure that reaches the measuring instrument.
What are the benefits of using one?
Overpressure protection helps prevent instrument failure, reduces maintenance needs and improves the safety and reliability of measurement points.
How is it installed?
Overpressure protection devices are installed directly ahead of the measuring instrument in the pressure line, matching the connection type of the process and instrument.
Which pressure ranges are covered?
They are available for a wide range of industrial pressure ratings, suitable for both low and high process pressures.
What materials are used?
Common materials include stainless steel, steel and other corrosion-resistant alloys selected for strength and long service life.
Can they be used with different media?
Depending on the material and sealing selection, they are suitable for both gaseous and liquid media.
How do they differ from standard isolation valves?
Overpressure protection devices include a pressure limiting or damping function, whereas isolation valves only open or close without limiting pressure.
Can they be retrofitted?
Yes, they can be integrated into existing measurement setups provided the connection types and space requirements are met.
How do they support maintenance?
By protecting instruments from overpressure, they reduce the need for frequent repairs and minimize downtime.
How do I select the right device?
Consider the maximum process pressure, the instrument to be protected, the medium and the connection type when choosing the correct overpressure protection device.
What is a protection threshold?
The protection threshold is the maximum pressure allowed to reach the instrument; the device ensures this value is not exceeded.
Are these devices useful for dynamic pressures?
Yes, they are particularly useful where rapid pressure changes or surge conditions occur.
Do they affect measurement accuracy?
When correctly specified, overpressure protection devices do not adversely affect measurement accuracy and help maintain reliable readings.
What types of seals are used?
Seals are chosen according to media and temperature conditions, and can be elastomeric or metallic depending on the application.
How do temperature and medium influence selection?
Material and sealing choices depend heavily on operating temperature and media compatibility to ensure durable performance.
Can they be used with gauge valves?
Yes, overpressure protection devices are often combined with isolation or test valves to provide complete protection and handling flexibility.