Safety shut-off valve (SAV) Type 53 N/H for overpressure and underpressure protection
Protects downstream equipment in gas pressure regulation systems against impermissible overpressure and underpressure.
Overpressure & Underpressure Activation
Monitors both pressure limits; the valve closes when triggered.
SAV Type 53 N/H: Protection against overpressure and underpressure in gas pressure regulation systems
The SAV Type 53 N/H safety shut-off valve protects downstream equipment, for example in gas pressure regulation systems, against impermissible overpressure and underpressure. The pressure to be monitored is fed to the measuring mechanism via a measuring pulse line. If the pressure exceeds or falls below the set response pressure, the mechanism is triggered and the valve closes.
The standard version is designed for gases in accordance with DVGW Worksheet G260 and for non-aggressive gases. Special versions are available for other gases. An integrated diaphragm rupture safety device ensures that a low-pressure trip occurs even in the event of a diaphragm rupture.
The 53N and 53H measuring units are available for different operating pressure ranges: the 53N is used as standard for operating pressures up to 50 mbar, whilst the 53H is used for ranges above 50 mbar.
0.2–0.5 s response time
Depending on pressure, DN and measuring element.
−15 to +60 °C
Documented operating temperature range.
DIN, ANSI & special flanges
Connections to customer specifications.
Maintenance without removing the instrument
Maintenance work can be carried out on site.
Measuring element 53N or 53H
53N up to 50 mbar, 53H above that.
Overall length customisable
Adaptation to local conditions.
Advantages and specifications of the SAV Type 53 N/H
Fast and accurate triggering
Maintenance-friendly design
Adaptation to the installation situation
Technical data for the Type 53 N/H safety shut-off valve
An overview of the most important, clearly documented specifications – from response time and temperature to media, measuring mechanism, connections and installation position.
The required response pressures depend on the measuring mechanism and spring design. According to the product documentation, other set pressures are available on request.
Design and operation of the Type 53 N/H safety shut-off valve
The Type 53 N/H safety shut-off valve monitors the system pressure and automatically shuts off the gas flow as soon as the set upper or lower response pressure is reached. The measuring mechanism, actuator and control element interact mechanically to ensure a reliable safety shut-off.
How the Type 53 N/H safety shut-off valve works
If the monitored pressure rises above the set upper response pressure, the diaphragm moves against the overpressure spring. The trigger mechanism is released and the valve closes under spring force.
If the pressure falls below the set lower response pressure, the diaphragm moves in the opposite direction against the underpressure spring. This also triggers the mechanical closing process.
In the event of a diaphragm rupture, gas enters the spring chamber and is vented via the ventilation line. The pressure in the diaphragm chamber drops and the SAV trips as it would in the event of low pressure.
Before reopening, the integrated pressure-equalising valve allows pressure equalisation to take place upstream and downstream of the valve plate.
Sensing element, actuator and control element
The SAV Type 53 N/H essentially consists of three assemblies: the measuring mechanism, the actuator and the control element. The measuring mechanism detects the pressure supplied via the measuring pulse line and mechanically compares its effect with the setting of the overpressure or underpressure spring.
When the set response pressure is reached, the measuring unit releases the trigger mechanism. The actuator transmits this trigger signal to the control element, which performs the actual shut-off function and automatically interrupts the gas flow.
In addition, the SAV features an integrated pressure-equalising valve and a diaphragm rupture protection device. The 53N and 53H measuring mechanisms are available for different operating pressure ranges.
The complete steps for commissioning, adjustment and maintenance can be found in the operating instructions.
Technical Specification and Enquiry Regarding the SAV Type 53 N/H
The key factors for technical selection include, in particular, the operating pressure to be monitored, the desired upper and lower set points, the medium, the temperature, the nominal diameter, the flange standard and the installation configuration. For customised versions, the connection orientation and overall length may also be taken into account.