baltur BGN 100 DSPGN, Instructions Manual

Page: 10 / 48

10
GAS FEED SYSTEM AT AVERAGE PRESSURE a few bars (see BT 8058-BT 8530/1-8531/1)
When high delivery is required, the Gas Distributing
Company requests the installation of a unit comprising
a pressure reducer and a meter, and then connects it
to the gas pipe network at average pressure (a few
bars).
This unit can be supplied by the Gas Distributing
Company or by the user, but should be according to
the Gas Company’s precise instructions.
The unit’s pressure reducer should be large enough to
supply the maximum gas delivery required by the
burner at the rate of pressure normally estimated for
it.
From experience, we would recommend utilising a
large-scale reducer in order to attenuate the notable
increase in pressure which occurs when the burner
comes to a standstill, with a high delivery. (Regulations
require that the gas valves close in less than one
second).
As an indication, we would advise using a reducer
capable of producing at delivery (m
3
/h) about double
that of the maximum amount estimated for the burner.
If several burners are to be used, each one should
have its own pressure reducer; this will enable the
gas feed pressure to the burner to be maintained at a
constant level even if only one burner is operating at
the time.
Consequently, it is possible to accurately regulate the
delivery and therefore the combustion, and thus
improve yield.
The dimension of the gas pipeline should be in function
with the quantity of gas it has to deliver. We advise
maintaining the load loss at a low level (not more than
10% of the gas pressure value at the burner); it should
be kept in mind that the load loss is added to the
pressure existing when the burner stops and therefore
a subsequent start up will occur at a pressure that
rises in accordance with an increase in the pipe’s load
loss.
Should the gas pressure reach unacceptable values when the burner stops (rapid closure of the gas valves), it is necessary
to install between the reducer and the first valve of the burner an automatic overflow valve and relative conveying pipe, of
suitable section, in the open air.
The end of conveying pipe in the open air should terminate in a suitable place, be protected from rain and have a flame
trap. The overflow valve should be regulated in such a way as to completely unload excessive pressure.
See diagram BT 8058 for gas pipeline dimensions.
Near to the burner should also be fitted a cut-off ball cock, a gas filter, an anti-vibration joint and a flanged fitting (see
BT 8530/1 and BT 8531/1).
DIAGRAM FOR CALCULATING THE DIAMETER OF THE
PIPES IN RELATION TO THEIR LENGTH AND GAS FLOW
N° BT 8058
DIAMETER OF PIPES IN INCHES
PRESSURE DROP IN mm OF H
2
O
FLOW IN m
c
/h OF METHANE p.a. 0,60
LENGTH OF PIPES IN METERS