tube
A hose is a flexible elongated hollow body with a mostly round cross-section in contrast to an inflexible tube . Since all pipes also have a certain flexibility, the transition is often fluid. Also corrugated metal pipes are either corrugated tube or corrugated tube called.
The term hose assembly refers to a hose that has been installed for permanent use.
variants
From a topological point of view, straight tubes are hollow cylinders , while air tubes in vehicle tires are tori from this point of view . Cylindrical hoses have two ends and can be temporarily wound up or permanently formed into a helix (commonly known as spiral hose (1)) in order to be elastic in length. Toroidal tubes can be twisted into an 8 (this is how early racing cyclists shouldered their replacement tubular tires with both upper arms) or a 3-fold ring.
A tight hose can be used as a conduit for conveying solid , liquid and gaseous substances, serve as their container or obtain desired properties through a medium inside. Even in ancient times , supplies were kept in flexible containers made of leather or animal intestines, which were called tubes, such as the wineskin .
Hoses are also used as protective sheaths, for insulation or for thermal insulation . A hose that is used to protect cables, for example, does not have to be tight. A filter hose is also not tight.
A tube which has been preformed in the production to predetermined dimensions, shapes and bends and is provided as a component for a particular device is molded tube called.
Hoses can have several lumens (cavities) next to each other (2 each for welding gases acetylene and oxygen to the welding torch or for the outward and return lines of a cooling circuit; 3 for an irrigation hose spraying out of small holes that should lie flat) or inside one another (low-loss hot water Circulation lines ; heating or cooling line (s) within a transport hose ; drying python a dispensing system for beverages - several product hoses, two hoses of the cooling circuit and a CO 2 control line are encased in an insulating hose).
Hose lines
In many cases, hoses are used as hose lines for the transport of materials when pipelines cannot be used for physical or economic reasons, for example at moving starting and destination locations, in hard-to-reach places or when pipes are too heavy or too expensive.
physics
Hoses are exposed to multiple mechanical and thermal , often also chemical and electrical loads. In hydraulic systems (which includes the braking system in cars) they transmit high pressures , while there is a strong negative pressure in fire service suction hoses . Cooling water hoses are stressed by pulsating pressure fluctuations, temperatures above 100 ° C and chemical additives, oil and hydraulic hoses by aggressive components of the oils. Air intake hoses can cool down significantly at high flow speeds. When used in pneumatic conveying , hoses must withstand heavy wear .
With all these loads, hoses must remain flexible, must not contract or expand, not become brittle or soften and must be resistant to chemical influences.
One of the most important physical quantities of a hose is the so-called (dynamic) pressure loss : Due to the friction of the flow on the pipe wall, the pressure decreases with the flowing medium as the length of the hose increases. The friction loss depends on the material being conveyed, the hose diameter, the conveying speed, the surface properties of the hose wall and the laying. A hose that is laid straight creates a significantly lower pressure loss than one that is laid in many bends. If the hoses are open on one side, only the pressure loss acts on the hose.
Dimensions
As with pipes , the dimensions of hoses usually refer to the inside diameter. For historical reasons, dimensions in inches are still often to be found. The correct indication of the nominal width according to EN ISO 6708 is by the designation "DN", followed by a number (approximately) corresponding to the inner diameter in millimeters.
In addition to the inner diameter, the outer diameter (OD = Outside Diameter), the wall thickness and the length can also be specified for each hose. The designation DN 6-15 can mean, for example, that the hose has a nominal diameter (inner diameter) of 6 (approx. 6 mm) and a length of 15 meters.
materials
Hoses are made of different materials depending on their intended use :
- Natural rubber ( rubber )
- Synthetic rubbers (e.g. EPDM, NBR, SBR)
- Plastics (e.g. PVC , PUR - polyurethane , PA - polyamide , PE - polyethylene , silicone )
- Fiberglass
- Metals , see metal hose ( metal hoses are also known as flexible pipes )
- Vegetable fibers
- animal raw materials
- technical fabrics
Manufacturing
Extrusion
There are basically different methods to hoses extrude . Usually the extruder produces the finished hose. These hoses are usually smooth on the inside and outside. One speaks of smooth hoses. Many of these hoses are reinforced with a fabric insert, such as pneumatic hoses. Many plastic films are also manufactured as blown film tubes and then, cut lengthwise, folded into film.
In another technique, it is not the closed tube that is extruded, but an open, endless profile, the long sides of which are then brought together in a straight line or wound up in a helix and welded along the edge. These hoses are often more or less corrugated on the inside and outside, depending on the profile shape. They are often reinforced with fabric inserts, wire or plastic helices.
Another option for hose production is extrusion onto a long mandrel. This can be a flexible plastic mandrel or a rigid metal mandrel. When manufacturing on a metal mandrel, the length of the hose to be manufactured is limited because the mandrel has to be removed again. Larger lengths are also possible when using flexible mandrels. Removing the mandrels is then the last step in production. In some areas, these mandrels are only inserted after the extrusion. The mandrel determines the inner diameter of the hose.
Welding
Wrapped hoses are usually welded at the joint edges. In the case of film tubes, prefabricated plastic films (width in the centimeter range) or textile webs are wound up in a spiral and welded with an overlap. Usually these hoses are reinforced with a steel or plastic helix.
Vulcanize
One or more layers of plastic ( rubber ) are vulcanized into a hose . The hoses consist of a tight inner layer (core), a carrier material on top and another layer for mechanical (and chemical) protection on the outside. The structure and composition can vary greatly depending on the requirements. Using suitable materials, hoses can be produced for almost all requirements. The hoses are usually first wound on a mandrel and then vulcanized. The mandrel is then removed again. Vulcanization can also be necessary for single-layer products if the selected material has to be crosslinked in order to obtain defined properties or resistances.
Sewing
The materials are sewn helically or lengthways to form a tube .
Jamming
Usually, thin, endless strips of fabric are clamped in a helical shape in a U-profile made of metal to form a hose. The U-profile is also known as a clamping profile. Hence the term clamping profile hose or CP hose (Clamp Profile).
Wrapping and braiding
Several layers of material are wound onto a mandrel. By overlapping and combining the material layers, such as braiding of textile material, and clamping at the ends, a tube is obtained after the mandrel has been removed.
Application examples
Some common modern uses:
| application | materials |
| Garden hose | Plastic, rubber, synthetic fibers |
| Sweat hose (irrigation) | Recycled product made from used tires |
| Insulation for electrical lines | Plastic, rubber |
| Sanitary fittings | Metal, rubber, plastic |
| Thermal insulation for heating pipes | plastic |
| Hydraulic systems | Metal braids, yarn braids for flexible hoses, rubber |
| Concrete pumps | Metal, rubber, plastic |
| Gas systems | Rubber, natural fibers, plastic |
| Gas suction | Natural fibers, plastics, fabrics |
| Bulk transport | Rubber, plastic, metal |
| fire Department | Rubber, synthetic fibers, natural fibers, metal ( suction hose ) |
Vehicle hoses
Hoses are also indispensable in many places in cars and other vehicles :
- Tubular tire , see also : Bicycle tube
- Windscreen washer
- Air intake hose
- Cooling water hose
- Fuel hose
- Power steering
- Brake hose, see also : Stahlflexleitung
- Wiring harness
- Air preheating
- heater
- Motor control (negative and positive pressure hoses)
Hose connections
To connect hoses to one another or from one hose to other connections, the following are used:
- Hose connector , short pipe section for connecting hoses
- Claw coupling (hose connection) - for example GEKA - consistently 2 claws per coupling half (a total of 4 results in a rigid connection) and clockwise closing, about 90 ... 120 ° locking angle engaging with cams, but only to be closed by hand without pressure
- Fire brigade coupling - Storz coupling
- GARDENA System - Water Hose Connector System
- Hose screw connection - faucet connection garden hose or washing machine 3/4 inch, nursery 1 ", shower hose or pressureless storage tank 1/2", angle valve for basin mixer 3/8 "
- Luer system (Luer slip and Luer lock) - plug-in cones, particularly in medicine
- Compressed air quick connect coupling - NW 7.2, 5 or 2.7 mm, each 0… 35 bar
- Safety coupling (ventilation coupling)
- Hose quick connector
- Quick connector - for hard 4, (5), 6, 8, 10, 14 mm outer diameter PU hoses, 0… 15 bar compressed air accessories
- Cutting ring screw connection - (for pipe) with insert sleeve also for hose 4… 18 (42) mm outer diameter, 180… 50 bar
- Hydraulic hose - pressing with fitting, sealing plug-in connection, possibly with screw locking
- Valve connection thread on pressurized gas cylinders, gas-specific, (largely) standardized across Europe
- Dunlop valve with valve hose; Bicycle valve adapter, valve connection head (for Dunlop / bicycle, Sclaverand + Presta / racing bike, Schrader / car)
-
Hose connector
- NBR rubber hose section, elastic, into which a 5 mm PE hose is inserted (Volkswagen central locking pneumatics around 1980)
- Socket with sealing ring and retaining edges that allow the hose to be pulled out only after pressing a ring-shaped button (release ring), typical for rigid PU hose with OD = 4, 6 or 8 mm
- Push-in sleeves for flexible hose (grooved hose, reinforced hose for electrical installation)
- Screw sleeves for helical grooved hose, e.g. with wire stiffening plus hose tie with hump bridge (for vacuum cleaner, suction)
- Quick release couplings - CPC series, also drip-free, with release button, click, coaxial double, coded up to 6 or 10 times
See also
Web links
Individual evidence
- ↑ druckluft-fachhandel.de quick release coupling NW 7.2
- ↑ Safety coupling (ventilation coupling) druckluft-fachhandel.de safety couplings
- ↑ druckluft-fachhandel.de quick connectors
- ↑ timmer-pneumatik.de cutting ring fittings
- ↑ https://www.aventics.com/de/produkte/pneumatik-produkte/pneumätze-verbindungenstechnik/verschraubungen-mit-steckschluss/?no_cache=1