General technical explanations
User information
Our pressure monitoring products may
only be installed and started up by
authorised specialists. The safety regula-
tions of country-specic authorities must
be observed, especially when working
with mains voltages and oxygen, and in
potentially explosive areas.
Product information
The technical information in this catalogue
is based upon fundamental testing during
product development and empirical values.
The information cannot be used for all ap-
plication scenarios.
Testing of the suitability of our products
for a specic application (such as the
checking of material compatibilities)
remains the responsibility of the user. It
may be the case that suitability can only
be veried by appropriate eld testing.
Mounting position
For mechanical and electronic pressure
switches as well as transmitters there is no
limitation due to the mounting position
with regard to the accuracy of the pressure
measurement.
However, other boundary conditions of the
application may require a certain mounting
position, e. g. horizontal installation to avoid
waterlogging on the electrical connection
or vertical installation to prevent debris from
accumulating in the bore of the pressure
connection.
IP protection class
The IP protection class is a defined protec-
tion level code (sealing) of electrical equip-
ment housings in line with IEC 60529 (for-
merly DIN 40050 – Part 2). Protection of a
housing against the following is tested here:
• The penetration of solid extraneous
particles, such as dust
• Access of hazardous parts
• Penetration of water
IP protection tests are performed as type
tests.
The IP protection type code, made up of two
digits, specifies the protection of a housing
against the penetration of solid extraneous
particles and water.
The numeric code therefore provides con-
clusions to be drawn on the level of personal
safety as well as the functional protection
/ mid to longterm functional reliability of
electrical equipment.
Protection types IP00, IP65, IP67 and
IP6K9K
IP00:
No protection against penetration of solid
particles or water, no protection against
contact.
IP6X:
Protection against penetration of dust (dust
proof). Full contact protection.
IPX5:
A jet of water from a nozzle, aimed at equip-
ment (such as a pressure switch) from all
directions, must not have any harmful effect.
IPX7:
Protection from water, when equipment
(such as a pressure switch) is immersed in
water under defined pressure and time con-
ditions. Water must not penetrate into the
equipment in harmful quantities.
IP6K9K:
Devices satisfying these requirements must
be dust-proof and be able to withstand loads
during the use of high-pressure cleaners
and steam jets. The standard stipulates a
water pressure from 80 to 100 bar at a tem-
perature of 80 °C for testing.
IP6KX:
Dust must not penetrate. Letter K: Specific
to the electrical equipment of road vehicles.
IPX9K:
Protection against penetration of water at
high pressure / for steam jet cleaning. Water
aimed at the housing from every direction
at greatly increased pressure may not have
any damaging effects.
We are able to oer IP67 / IP6K9K for many
of our mechanical and electronic pressure
switches (pre-wired or with integrated
connector) and for our transmitters.
IP67 / IP6K9K is the recommended pro-
tection for mobile hydraulics and any
equipment exposed to the outdoor
environment.
Cylindrical threads
Cylindrical threads are either sealed on the
front by underlaying an appropriate sealing
ring (such as a copper sealing ring) or by
already having integrated O-rings or gakets.
If the corresponding thread types do not
provide specifications regarding the rough-
ness of the counter sealing surface, we re-
commend the following values:
• Ramax 1,6
• Rmax 6,3
• Rmr(-0,10) > 5 % Cref 5 %
Conical threads
(cone-shaped threads)
Conical threads guarantee tolerance com-
pensation of the two threaded parts. The
sealing function is realised with thread
flanks which deform permanently and enter
into a metallic frictional fit. Conical threads
are not screwed in down to the screw-in
depth, but fixed with the tightening torque
required for the leak tightness.
Remember not to exceed the permitted
tightening torque of the pressure switch or
transmitter presented in the following table
(to prevent damaging the threaded pin
beforehand, causing it to become untight
during operation or to snap off when
tightened).
Tightening torques of steel threads
The specifications below are to be under-
stood upper material thresholds for the
housing of pressure switches or transmit-
ters. Remember during installation that the
type and material of the seal, the condition
of mating surfaces (e.g. dry or oily) and the
material of the counter-piece all have a
bearing on the tightening torque.
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