Technical details

LD

S

8.300

Leak monitoring system

s

Positive pressure leak detector type DLR-G ... PM

System description

The positive pressure leak detector type: DLR-G ... PM is

suitable as per approval for monitoring double-walled piping

through which water-hazardous

fluids with a

flashpoint belo

w

and above 55 °C is transported

.

Functioning principles

The necessary pressure in the surveillance space of the dou

-

ble-walled piping depends on the actual operating pressure in

the medium pipe (inner pipe) and is generate

d

- by topping up regulated by pressure changes from

a

stationary nitrogen pressure reservoi

r

connected continuously to the surveillance space

:

Operating Mode C (continuously)

- from a mobile pressure reservoir which is only connected

when the line is put into operatio

n

or during a function test: Operating Mode I (interval

)

Operating modes C and I can be chosen by adjusting the

switch on the board in the leak detector.

The surveillance space is connected with the leak detector b

y

means of the connecting leads. The pressure which builds u

p

is measured by the pressure sensor. If pressure drops to th

e

value set previously for ALARM-ON due to a leak, the optical

and acoustic alarm will be triggered.

In operating mode C the monitoring pressure is regulated after

putting the system into operation by pressure changes whic

h

top up from a stationary nitrogen pressure reservoir whic

h

is continuously connected with the surveillance space an

d

equipped with a pressure reducing valve.

In operating mode I the monitoring pressure (TOP-UP OFF) is

set just once when the system is put into operation by a pres

-

sure reservoir which is not continuously connected. There is no

top-up regulated by pressure changes in subsequent opera

-

tion. Any drop in pressure which reaches the ALARM ON point

and triggers the alarm must then be compensated by connect

-

ing the pressure reservoir till the previously set TOP-UP OFF

level is reached.

The manufacturer of the leak detector stipulates that the lea

k

detector must be undergo a maintenance check once a yea

r

on a recurring basis by an expert firm accredited according

to WHG in order to ensure correct functioning and operatin

g

safety

.

Switching pressures see Table 1 in Worksheet LDS 8.301

.

Technical basi

s

The scope of application of the leak monitoring system is lim-

ited by maximum piping lengths. The alarm is triggered by th

e

leak detector at the latest when a pressure which is at least

1.0 bar over the maximum transport pressure of the medium

pipe (inner pipe) is reached (see Table 1). The types of layin

g

are illustrated in Worksheets LDS 8.304 and LDS 8.305

.

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 DLR-G ... PM leak detector and the Work

-

sheets for the FLEXWELL® piping. The conditions set out in the

approval for the double-walled piping and the DLR-G ... P

M

leak detector must be complied with.

DLR-

G ..

.

Positive pressure l

eak monitorin

g

for horizontal and

vertical laying and

two- and multiple

line system

s

31.03.2026 Subject to technical changes. Page 18