Specifications for safety Relief type 121


Safety Relief valve type 121
The Sensus safety Relief valve type 121 is also known as a back-pressure regulator. The safety Relief has a single diaphragm with a balanced valve. This makes the Sensus type 121 very accurate. It is a modulating relief and not a pop-up type. Depending on the operating conditions, a membrane box with a diameter of 8″, 12″ or 16″ can be chosen. The safety relief is available in connection sizes ranging from 3/4″ up to 4″.
Types
121-8, 121-12 and 121-16.
Maximum operating pressure
The maximum inlet pressure depends on the version and the Relief spring.
Operating temperature
-28.9 – +65.5° C (-20° F +150° F).
Spring range
12.0 – 700.0 mbarg (with different springs).
Connection sizes
3/4 “, 1”, 1.1/4 “, 1.1/2”, 2 “, 2.1/2″ NPT.
Flanged in DN50 PN10, 2″ANSI125lbs, 3” ANSI125lbs and 4 “ANSI125lbs.
Applicable gases
Natural gas, propane, butane, air and nitrogen. Various designs are available for special (corrosive) gases.