grandimpianti EM 10 - EM 15 Instrucciones Para La Instalación Y Para El Uso página 17

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5.7 CONNECTION FOR STEAM AND
CONDENSATION (steam models, only)
Dryers heated with steam must be installed
in full conformance with all national and
local regulations.
The pipes and gate valves on the steam feed
and condensation return must be properly
sized to handle the steam pressure, tempera-
ture and consumption of the machine. In
any case, their diameter must not be smaller
than the intake and outlet connections on
the machine.
The normally acceptable feed pressure
ranges from 150 KPa (approx. 1.5 bar) to
600 KPa (approx. 6 bar).
In any event, the optimum operating pres-
sure is indicated on the identification plate
on the machine.
The steam control solenoid valve supplied
with the machine must be connected to the
steam intake on the machine.
ATTENTION
A fine-mesh filter must be installed to
prevent impurities in the line from dam-
aging the solenoid valve membrane. The
installation of a cut-off gate valve is also
essential for performing repair or main-
tenance operations or in case of emer-
gency.
The machine is also equipped with a con-
densation outlet. A steam trap must be con-
nected to this outlet, and the size of the
steam trap depends on the distance between
the outlet and the steam trap as well as on
the specifications of the system.
ATTENTION
It is always advisable to install a check
valve after the steam trap to prevent con-
densation from backing up into the trap.
A cut-off gate valve is also essential for
performing repair or maintenance opera-
tions or in case of emergency. A flow in-
dicator is also necessary for verifying that
the steam system is working correctly.
Other elements such as bleeders for remov-
ing air from the pipes, heat exchangers,
pumps for lifting the condensation, super-
heaters, and plenum chambers should be
installed in accordance with the type of
steam system used and the capacity of the
machine.
The steam must be saturated (without air
content).
The following is a list of the principal types
of steam traps and their characteristics:
5.7.1 LIQUID-EXPANSION THERMO-
STATIC STEAM TRAP
This trap does not retain condensation, so it
is not subject to freeze-up.
It offers a high discharge capacity, even
when cold.
The minimum distance between the outlet
on the dryer and the steam trap is 2 meters.
The trap cannot handle large swings in
steam pressure.
The flexible thermostat element cannot han-
dle corrosive condensation.
5.7.2 BIMETALLIC THERMOSTATIC
STEAM TRAP
Besides offering the advantages of the liq-
uid-expansion thermostatic steam trap de-
scribed above, the bimetallic thermostatic
steam trap offers greater resistance to wa-
ter hammering and corrosive condensation.
However, it is not recommended in systems
equipped with a temperature control device.
5.7.3 FLOAT-TYPE STEAM TRAP
This unit can handle abrupt changes in load
and pressure.
It smoothly discharges air present in the
pipes.
Its simple design enables it to be worked
on easily during maintenance or in case of
malfunction.
It discharges condensation quickly.
The float cannot withstand corrosive con-
densation, water hammering or superheated
steam.
The choice of this type of steam trap de-
pends on the operating pressure in the sys-
tem.
5.7.4 INVERTED-BUCKET STEAM
TRAP
This unit easily handles water hammering
and superheated steam.
Upon request, it can be equipped to with-
stand corrosive condensation.
Simple construction.
In order to function properly, it must be
perfectly sized to suit the system in which
it is installed.
It responds more slowly to changes in pres-
sure and load.
15
If the pressure drops, continuous discharges
of steam may occur.
5.7.5 THERMODYNAMIC STEAM
TRAP
This type of steam trap is smaller than the
types previously described.
It offers a large condensation discharge ca-
pacity.
It has a very wide operating range in terms
of both temperature and pressure.
It can operate with superheated steam and
handle corrosive condensation.
It easily handles water hammering.
There is no risk of freezing if the condensa-
tion outlet points downward.
It cannot operate at pressures lower than 0.3
bar and when back pressure at the outlet
exceeds 80% of intake pressure.
ATTENTION
Be sure to use components which can
handle the pressure and temperature of
the steam and condensation.
5.8 GAS CONNECTIONS: INSTALLA-
TION OF GAS-FIRED MACHINES
Never attempt to "do-it-yourself" when
installing or maintaining gas-fired units.
Have a qualified installer perform these
procedures.
The installation of gas-fired equipment
must be carried out in full conformance
with local and national regulations.
The unit is equipped at the rear with a 1/2"
(1" on model EMG 55) gas connection. The
system is set up to operate with the type of
gas, gas pressure and category listed on the
last page of this manual.
When installing the unit, make sure that the
type of gas supplied is the one the machine
is designed to use. Poor combustion caused
by using the wrong type of gas can gener-
ate carbon monoxide, a highly toxic gas.
An outlet for vapours and burnt gasses is
also located on the rear of the machine. The
diameter of the outlet is listed in the techni-
cal specifications. All models are equipped
with a single outlet for both the vapours
generated during drying and the burnt gas-
ses. Only the model EMG 55 is equipped
with two separate outlets.