LD
S
Technical details
8.200
Leak monitoring system
s
Vacuum leak detector type VLR 410 PMMV Si
System description
Leak monitoring on the vacuum principl
e
The vacuum leak detector type VLR is suitable and approved
for the monitoring of double-walled piping used for transport
-
ing water-hazardous flammable substances with a
flashpoint
> 55 °C (e.g. heating oil, diesel fuel, water-glycol mixture,
AD Blue, ...).
Version
s
VLR 410 PMMV Si: max. operating pressure in the inner pip
e
25 bar (a leakage probe or a solenoid valve or both can b
e
connected in addition)
.
Alarm-triggering values
VLR 410 PMMV Si: on > 410 mba
r
Functioning principl
e
The vacuum pump installed in the leak detector creates a
partial vacuum in the surveillance space. This partial vacuum
is measured by a pressure sensor. Through monitoring the
vacuum, leaks are therefore automatically detected
.
In the event of a drop in the partial vacuum below the lowe
r
value of the monitoring partial vacuum (pressure rise) due t
o
a leak, an optical and acoustic alarm is triggered. Minimal, un-
avoidable permeability (not leaks) are regulated automaticall
y
by the leak detector without triggering the alarm if they li
e
between the upper and lower values of the monitoring partial
vacuum. Subsequent evacuation is carried out by the vacuum
pump in the leak detector
.
In every case in which the alarm is triggered by the VLR410/E
the vacuum pump is automatically switched o
ff. It can only be
switched on again by throwing the toggle switch “Operation”.
Technical basis
The scope of application of the leak detection device must b
e
limited to fixed maximum pipe lengths due to the laws of phys-
ics. These depend on upper and lower points of reference an
d
on the type of lying of the double-walled safety piping. The
types of laying are illustrated in the Worksheets LDS 8.214 ff.
Tips for installation
The leak detector may not be installed in explosion-proo
f
areas. The installation of the leak detector can be insid
e
closed, dry rooms or outside of buildings.
Installation/commencement of operations/operation/
function testin
g
Detailed descriptions can be seen from the approval docu
-
mentation of the VLR leak detector. The conditions set out in
the approval for double-walled piping and the VLR leak detec
-
tor must be complied with
.
Example
leak monitorin
g
diagram Vacuum
VLR ...
K
P
VT
31.03.2026 Subject to technical changes. Page 7
