All the Hose Knowledge in one Article
Hoses are used in many applications, whether for transporting raw materials and solids, gases or liquids. It is important that the hoses used are able to withstand the physical conditions and external influences. To ensure exactly this, in this article we provide you with comprehensive knowledge about our hose products and give you tips on what you should look out for.
A correctly selected hose and correct use minimise risks such as leaks, bursts or other failures that can lead to hazards or high costs. Find out everything here! And if you still have any questions, please get in touch with our experts at any time - we will be happy to support and advise you!
Writer
Schauenburg Hose Technology Group
Content
General
Our hoses are designed
for the conveying of dry, gaseous and liquid media. The user is
obliged to use our products only on the basis of our stated specifi
cations. All our technical data are the result of internal tests and
trials in accordance with international standards. They only serve
as a guide and refer to a fluid and ambient temperature of +23°C,
static pressure and vacuum loads and straight hose lines with a
length according to the corresponding test standard. The specified values do not apply with deviating temperatures, pulsating
pressure, vacuum load, vibration of the hose pipe or the connection
sides, heavily curved hoses or improperly attached hoses. In
these cases, the suitability for use must be verified by the user.
If there is no experience in using our products, we strongly recommend
prior testing or consultation with our technicians. This is especially important at operating conditions with mutual loads
(movements), high temperatures, vibration, abrasion, water vapor,
chemical loads or S-shaped hose linings. The application examples
provided by us are not binding. To achieve a long service
life, the following should be noted for selection and use. Choise
of products according to the maximum operating pressure given
in the catalogue. The hose should never be deformed by force
(e.g. kinking, crushing, running over with vehicles, twisting, etc.).
Dragging hose pipe over rough floors and sharp edges needs to
be avoided. The hose should not be permanently bent at the couplings
or subjected to excessive tensile stress. Contact of unprotected
hose ends with the flow media should be avoided. Emptying
and careful cleaning may significantly extend the life of a hose
pipe.
Storage of Thermoplastic Hoses
The storage area must be cool, ventilated and suffi ciently dry.
High ambient temperatures above +45° C without any airflow can
permanently deform thermoplastic hoses. Please note that such
temperatures may arise in direct sunlight, even when hoses are
packaged. The permanent stack height must be adapted to the
respective product and ambient temperature. Hose coils/lengths,
which are loaded with a higher weight under summer temperatures, may be deformed. It is important to ensure that the hoses
are stored free of tension, so without strain, pressure or other
stresses, since tension encourages both permanent deformation
and cracking. For outdoor storage, thermoplastic hoses must not
be exposed to direct sunlight. The packaging must not be airtight.
Depending on the product, thermoplastic hoses must be protected
from permanent UV and ozone radiation.
Transport of Thermoplastic Hoses
Because of the constant movement, transport leads to much
greater mechanical stress for thermoplastic hoses than those
which arise during storage. High outdoor temperatures, the heat
accumulation in the truck/container and constant vibrations
during the journey can quickly lead to permanent deformation of
the hoses. Therefore, at high temperatures, the stack height during transport must be less than it is during storage. During transport,
thermoplastic hoses may not be thrown, dragged along the floor,
run over or stepped on. This could result in damage to the outer
layer and deformation of the spiral reinforcement. We assume no
liability for this. Therefore, care must be taken to ensure that no
damage is caused by improper handling.
Temperature Behavior of Thermoplastic Hoses
Unlike rubber hoses, the cold and heat have a great infl uence on
thermoplastic hoses. Plastic hoses change their fl exibility at low
or high temperatures of the media or the environment. At lower
temperatures, they can harden until they become brittle. At higher
temperatures they can become malleable. Because of these properties, the pressure and vacuum specifi cations for thermoplastic
tubes are exclusively linked to a temperature of the media and the
environment of around +23°C. If temperatures deviate from the
media or environment, we cannot guarantee compliance with the
indicated technical characteristics.
Influence of Sunlight on Thermoplastic Hoses
The UV radiation from the sun can attack the material and destroy
the hose over time. This happens in connection with the duration
and intensity of solar radiation, which is usually lower in the Northern
regions than in Southern regions. Therefore, a precise time period
cannot be given. The embrittlement of thermoplastic hoses
by UV radiation can be slowed down, but not completely stopped, by adding special UV stabilizers. These stabilizers also wear with
continuous UV irradiation. Some of our hose types are fitted with
these UV stabilizers as a standard to ensure a long shelf life under
direct sunlight. On request, any type of hose can be fitted under
certain conditions with UV stabilizers.
Pressure and Vacuum Behavior of Hoses
Genuine pressure hoses are all types which have a yarn reinforcement
as a pressure carrier. All hoses can change their length and
diameter and become twisted even within the specified pressure
and vacuum values. For hoses with yarn reinforcement as a pressure
carrier, changes of up to 5% in length and girth is normal,
even under laboratory conditions. Therefore, all operating conditions
which deviate from the norm infl uence the behavior of these
products even more. All hoses which have a spiral reinforcement
without any polyester yarn reinforcement are only suitable as pressure
hoses to a very limited extent, and are mainly intended for
vacuum applications. By design, a change in length of these hose
type of up to 30 % during use, even within the specified pressure
and vacuum value, is always possible. All possible length and girth
changes, as well as axial twisting of hoses must be considered by
the user during use. In use conditions, hoses must not be fi xed at
short distances as pipes are, but must be able to move freely at all
times. In soil, hoses may only be laid in adequately dimensioned conduits. In doing so, all possible changes in the hose geometry
need also to be taken into account at all times. We strongly recommend
that you determine the hose behavior in use by means
of prior testing and then carry out the installation. With spiral reinforced
hoses, the elongation and twisting in the case of overpressure
leads to a reduction of the inner diameter at the same time.
For hoses with steel spiral reinforcement, the spiral cannot completely
follow this reduction of the inner diameter. Thus, the spiral
can work through the hose wall to the outside and destroy the
hose. With permanent use in the overpressure range, we generally
recommend hoses with yarn reinforcement as the actual pressure
carrier. This prevents excessive elongation.
Based on DIN EN ISO 1402.-7.3, the values given for the burst
pressure with compressed air and pneumatic hoses were determined
at about 23° C and water as a pressure medium.
Using Hose Couplings
In suction applications, plastic spiral hoses can be integrated with
a variety of commercially available fittings. In the application, the
hose sucks firmly onto the fitting and seals itself off. In pressure
applications, spiral hoses are much more complex and are to be
permanently sealed due to the strain and change in diameter. Our
fittings, which are customized to the particular type of hose, are
ideally suited to this. When using standard fittings, please ask for
our respective procedures recommendations. With PVC yarn reinforced
and monoextruded hoses, make sure that the material has
a significantly lower notch toughness compared to rubber. Therefore, fittings may not have any sharp edges that can rip when
assembling the inner layer. If the thermoplastic yarn reinforced
hoses are fi xed to a hose connector by means of press sleeves or
hose clamps, make sure that the pressure is applied with the least
possible force. Otherwise, the hose layers can be cut through the
fitting or the hose clamp, whereby the hose becomes immediately
unusable. For safety reasons, we recommend hose connectors
with lower gearing than the thickness of the hose inner layer. Basically,
it should be ensured that, when using fittings, all kinds of
hoses are not bent sharply right behind the fitting.
REACH and RoHS Compliance
All subsidiaries of Schauenburg Hose Technology Group as being converters of raw materials made by third parties closely monitor and request their suppliers to comply with and update on any eventual changes
under REACH and ROHS Regulations.
Discharge Capability of Hoses
To derive electrostatic charges in the transport of powdery or granular
media, all plastic hoses can be used with copper wire or steel
spirals. Through the grounding at both ends of the braid or spiral,
these hoses are considered to be conductive. For use in potentially explosive areas, the TRBS 2153 must be followed. The usefulness of
hoses and compliance with all mentioned in the TRBS 2153 rules are
in each case, to consider by the user and to ensure.
ATEX Guideline
For the ATEX guideline it is not necessary if the hose is electrically
conductive or dissipative, it has to meet the requirements of the TRGS
727. ATEX approval can only be made for equipment (machines) or
components, but spiral hoses are no „equipment“ nor „components“
in terms of the ATEX directive 2014/34/EU. To be an equipment or component concerning the ATEX directive the equipment or components
must have an “autonomic function” like a motor. As hoses
do not haven an “autonomic function” ATEX approval is not possible.
However, if the hose meets the specifications according to TRGS 727
it is suitable for the use at e.g. a machine which is ATEX certified.
Fire Resistance Compliance
Hoses indicated as Fire resistant, follow the tests and classifi cations
of the materials used in the production of those hoses. As there are
several norms available regarding fire resistance, performance and testing, users should be aware that a compliance under one norm
does not ensure similar compliance under a different norm. Please
feel free to contact us when you are in doubt.
Dimensions & Weight
With hoses, reference is generally made to the inner diameter with
the exception of some drinking water and garden hoses. Where
appropriate, we also indicate the wall thickness for the sake of completeness, however the wall thickness will not necessarily
define the outer diameter as this is influenced also by the hose
structure.
Weight references in the data sheet are for indication purposes
only and they are not contractual. We reserve the right to modify
the weights according to our production conditions, as long as the product maintains its original performance in terms of vacuum
resistance, working and bursting pressure, bending radius or other
performance information mentioned on the product pages.
Burst Pressure, Operating Pressure, Test Pressure & Vacuum
Burst Pressure: The burst pressure is the pressure under which a hose will become
destroyed due to the pressure. The test is always run in line
with the international standard DIN EN ISO 1402 or DIN 26057 according to the hose type. The burst pressure is used to define the
operating pressure taking account of the general safety factors.
Operating Pressure: The operating pressure is always determined in line with the international
standard according to the application and the type of
hose used: DIN EN ISO 7233 for PVC suction and delivery hoses, and yarn
reinforced hoses.
Test Pressure: Pressure that is maintained during non-destructive testing and for a
specified duration in order to verify the integrity of the hose assembly.
Depending on the hose construction, the test pressure is up to 50% above the operating pressure. At test pressure, the hose must not
show any leakage or permanent deformation.
Vacuum: Vacuum is the negative pressure that a hose can withstand wihout
resulting in flattening or detachment of the lining or layer separation.
The determination is always based on the international
standard according to the application and the type of hose used: DIN EN ISO 7233 for PVC suction and delivery hoses, and yarn
reinforced hoses & DIN 26057 for spiral hoses made with thermoplastic polyurethane
with steel wire reinforcement
Bending Radius
Smallest drum around which the hose can be laid without the
cross-section becoming significantly changed compared to the original shape. In each case, the test is performed in accordance
with the standard which determines the product.
Customized Types
Almost all types of hoses can be optimized to customer requirements
for the particular application. Wall thicknesses, dimensions, pressure
or vacuum support, colors, lengths and shapes can be already be customized for you. We are happy to answer your questions at any
time and assist you in finding the suitable hose for your application.
Phatalate-free
All our hoses are free of ortho-phtalates.
Food Grade Quality of Hoses
By definition, plastic hoses belong to the commodities that may be
intended for contact with food. The European Regulation EU 10/2011
makes a difference in Appendix 3 on page 75 between the 6 different
categories A, B, C, D1, D2 and E, according to which a foodstuff
commodity (hose) can be tested. The test for a particular category is
carried out using a simulant, and must be run on the fi nished component
(hose). The continued common practice of many manufacturers
to merely confirm that the hose basis suitable for foodstuffs
is not permitted. In the Regulation, all food is mostly assigned to a single simulant (category). The food categories for which our products
are approved are designated by printing on the hose. We publish
specific information on the contact time and possible exclusions in
our Declarations of Conformity, which are available at all times. When
choosing one of our products, it is the responsibility of the user or the
customer to check that it is approved for the intended food and the
contact time. Regulation 10/2011 can be viewed on the internet at eur-lex.europa.eu/LexUriServ/LexUriServ.do at any time. Of course,
we are also happy to advise you.
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