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Foundry and slag hose

What is inside the hose is ordinary. Everything outside it is not, and that is where this duty is decided.

Around a melt floor the hazards are not the ones a datasheet describes. The medium inside the hose is usually ordinary — cooling water, compressed air, argon for degassing. What is unusual is everything outside it: radiant heat from an open bath, splash from a pour, grinding sparks, slag, and people dragging things across the floor.

What this service does to a hose

The duty is external. A water-cooled electrode arm, a furnace panel or a degassing lance runs cool water at ordinary pressure. The hose feeding it sits within a few metres of molten metal. Radiant heat raises the assembly’s surface temperature far above ambient even though the medium is cold, and the braid — the load-carrying part — is the outside surface taking that heat.

Splash is a point event with a very high energy. Molten metal or slag landing on a braid does not gradually degrade it; it destroys wires locally in an instant. Broken braid wires do not leak. They simply stop carrying load, and the corrugation underneath then holds pressure it was never rated for alone — a DN25 corrugation without braid is rated 2.5 bar against 38 bar braided. That is why splash protection is a pressure-integrity item on this duty, not a cosmetic one.

Water plus heat is the worst failure. A cooling hose that fails near a melt puts water where water must never go. That consequence, rather than the cost of the hose, is what should set the specification.

Mechanical abuse. Melt floors are hard on everything. Assemblies get walked on, dragged, and caught by moving equipment.

What we would fit

ElementWhat we would supplyWhy
Hose316L annular corrugated for water, air and inert gasThe medium is ordinary; the environment is not
BraidDouble braid where the assembly is exposed or handledIt is the load path and it is what splash destroys
ProtectionInterlock armour sleeve or a heat-resistant outer over the braid in splash zonesSacrificial protection over the part that carries the load
EndsFlanged or heavy-duty threaded, guarded at the ferruleThe ferrule transition is where dragged assemblies fail
RoutingAway from the pour path and the drag path, with generous radiusThe best protection is not being in the way
A cooling hose failure near a melt is a water-into-metal event. That consequence should set the specification, the inspection interval and the replacement policy — not the unit price of the assembly. Tell us where the hose sits relative to the bath and the pour path, and we will specify protection for the realistic case rather than the nominal one.

What we would not fit, and what happens

An unprotected braid in a splash zone. Local wire damage, no visible leak, and a pressure boundary that is no longer what the drawing says it is.

Single braid on an exposed or handled assembly. There is no margin for damage.

Interlock hose carrying the water. It is not pressure-tight. It is a good armour sleeve over a hose and a bad hose in its own right on this duty.

An assembly with no inspection regime. The failure mode here is invisible from the outside until it is not.

What we need to size it

We needBecause
Medium, pressure and temperatureThe ordinary three, and usually the easy part
Distance from the bath and from the pour pathIt decides the radiant duty and the splash protection
Whether splash, sparks or slag can reach the assemblyIt decides whether armour is fitted
Whether the assembly is handled, dragged or fixedHandled assemblies get double braid and guarded ferrules
Ambient temperature at the hose, not in the buildingRadiant heat is the number that matters
Inspection and replacement interval you can actually keep toWe will design to the interval you will really achieve

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