EN - English - Instructions manual
7
4.1.2 Version with glass protection
device
The EXH series of explosion-proof housings has a
version with a glass protection device, installed on
the front opening of the housing. It comprises a
ange for linking with the housing, a closing ange
and a central, explosion-proof body containing a
strong, transparent glass, a 24Vdc motor, two winders
and transparent Mylar lm, installed in front of the
glass.
The motor uses 4 bevel gears to pilot a winder for
recovering dirty lm, while the other winder issues
clean lm. The motor is remotely controlled by a two-
wire ON-OFF contact (one common and one +24Vac/
Vdc).
h The control unit for the glass protection
device is supplied by the customer.
The transparent Mylar lm can be fed forward about
350 times.
When the lm is dirty the operator starts the motor,
so that the lm is fed forward until a clean image is
obtained (to completely replace the dirty lm in one
step, about 50mm of clean lm should be fed).
The end of the tape is marked by printing on the last
50cm of lm.
Film feed can also be started automatically by a
timing device if a suitable control system is used (this
is not supplied).
To change the lm, see the VIDEOTEC spare part
handbook (code OEXMYLAR).
4 Identification
4.1 Product description and type
designation
The EXH series explosion-proof housing has been
designed for use with cameras operating in industrial
environments in which there may be an explosive
atmosphere due to gas, vapours, mists, or air or
powder mixtures.
EXH housings comprise solid, cast Anticorodal
aluminium alloy from the AlSi7Mg EN AB-42000
group, the exact chemical composition of which is
dened in the UNI EN 1706 standard.
Depending on the model, all parts are powder-
painted and oven-cured or treated with special
coatings giving excellent resistant to UV light, to salt
spray and to atmospheric pollutants.
The camera body comprises a cylindrical tube, with
a ange that houses a strong, transparent glass;
opposite to the glass there is another ange that, as
well as closing the cylinder, also supports the plate to
which the camera is to be attached.
The housing has two holes for 3/4" NPT cable glands.
The cable glands must be selected according to what
is indicated by the EN/IEC 60079-14 Standard.
These cable glands guarantee an IP66 protection
level.
j We recommend using VIDEOTEC cable
glands or equivalent (Tab. 01, page14).
4.1.1 Version for thermal imaging
cameras
When using thermal imaging cameras, which are able
to detect heat emission, a special lter on the front
of the housing should be used.This housing diers
in that it has a window made mainly of germanium,
which guarantees the same strength and security
properties as those for standard glass. Range of
application from 7.5 to 14µm.
