| Pressure Safety Valve (PSV) |
A pressure safety valve actuated by inlet static pressure
and characterized by rapid opening or rapid popping action. This
safety valve is tight shut-off and is for safety only. Meets ASME
SEC. VIII (Not a Fulflo valve) |
| Pressure Relief Valve (PRV) |
A pressure relief device designed to re-close and prevent
further flow after normal conditions have been restored. (Fulflo) |
| Relief Valve (RV) |
A spring loaded pressure relief valve, actuated by the
static pressure upstream of the valve. The valve opens normally in
proportion to the increase in pressure over the set pressure. (Fulflo) |
| Safety Relief Valve (SRV) |
A pressure relief valve characterized by rapid opening or
pop-action in direct proportion to the pressure increase, depending on
the application. (Fulflo) |
| Conventional Safety Relief Valve
(CSRV) |
A spring-loaded pressure relief valve whose performance
characteristics are directly affected by change in the backpressure of
the valve. (Fulflo) |
| Backpressure |
The pressure existing at the outlet of a pressure relief
valve, due to the pressure in the discharge system. The pressure
can be constant or variable. It is the sum of the superimposed and
build-up pressure. |
| Cracking Pressure |
The pressure which the valve starts to leak flow through
the valve, but before the set pressure. |
| Set Pressure |
The inlet pressure the valve is adjusted to open, maintain
or control under service conditions. |
| Differential Set Pressure |
The pressure differential between the set pressure and
constant superimposed backpressure. |
| Superimposed Backpressure |
The static pressure existing at the outlet of the relief
device at the time the device is required to operate. It is a
result of pressure in the discharge system coming from another
source. This pressure may be constant or variable. |
| Overpressure |
The pressure increase or accumulation above the set
pressure when the valve is discharging flow. |
