Pressure Safety Controls; Safety Relief Valves - Emerson Copeland 4MTL-05 Application Manuallines

3.2

Pressure safety controls

3.2.1 Safety relief valves

CAUTION
High pressure! System leak! In the event that a pressure relief valve
activates repeatedly, check and replace it as needed in order to avoid a
permanent leak. Always check system for CO
pressure relief valve.
The compressor is fitted with a pressure relief valve on the discharge side (135 bar, factory mounted).
If excessive pressures are reached, the valve opens and prevents further pressure increase. CO
then blown off to the ambient.
An optional pressure relief valve (90 bar) is available for the suction side. Typically the suction side
of the system is anyhow protected by an additional pressure relief valve. This system pressure relief
valve is also acceptable for compressor protection.
The pressure relief valve does not replace pressure switches or additional safety valves in the
system.
▪ High-pressure side (HP):
Usually after a blow-off, pressure relief valves are never perfectly tight. It is therefore recommended
to replace the pressure relief valves after any blow-off.
The following pictures show the position of the pressure relief valve (high side) and the position of
the plug (low side).
PRV (high side)
Figure 16: Position of the pressure relief valve – Models 4MTL-12 to 4MTL-30 & 4MSL-08 to 4MSL-15
PRV (high side)
Figure 17: Position of the pressure relief valve – Models 4MTL-05 to 4MTL-09 & 4MSL-03 to 4MSL-06
AGL_Stream_ST_4MTL_4MSL_E_Rev01
135 bar
loss after activation of the
2
Plug (low side)
Plug (low side)
is
2
13