Furnace Hose
PRODUCT
FURNACE / FURNACE DOOR / DRY REFRACTORY HOSE
INDUSTRY
Steel, Glass, etc - where cooling is required in heat, flame or molten material environments
“Furnace Hose” refers to hose used in the steel making industry, primarily on electric arc furnaces, to provide cooling water to various parts of the process, including the door (Furnace Door Hose), and to the electrodes. These type hoses are used in various refractory operations.
Because of the high heat in this process, the hose is constructed with special protective covers to provide resistance to extreme radiant heat. In many applications resistance to radiant heat alone is not enough as the hoses are subjected to molten slag where flame resistance is required. Heat resistance is not the same as flame resistance. Many "heat resistant" covers are flammable and will burn when in contact with molten slag, destroying the hose quickly by simply disintegrating it.
Types |
“Furnace Door” hoses range in size from 1/2” to 3.0” inside diameter and are softwall (non-helix) construction. The hose is used to provide cooling water to the furnace doors. Furnace hoses over 4” in diameter usually contain a helix component to provide maximum flexibility without kinking. Many of these hoses provide cooling water to the electrodes. |  |
W.P. |
Hoses are normally designed for 150 PSI working pressure (W.P.) water services. | |
Bend Radius |
Since many hoses “hang” in the installation, the resistance to kinking as well as supporting the weight of the hose need be considered. Minimum bend radius design is necessary in many applications. In fact there are applications where the bend radius is exceeded, resulting in kinking and quick hose failure. Non-helix constructions have a minimum bend radius of 8:1; Wire: 6:1; Profax: 4:1. | |
HELIX |
A helix component is incorporated in larger i.d. hoses to provide the maximum kink resistance while remaining extremely flexible. The use of a helix enables the cover to be corrugated which also enhances flexibility. Steel and Profax (Plastic) helixes are used depending on the overall application requirements. The Profax is also referred to as "crush resistant" which means it returns to shape after being crushed. It is more flexible than wire and has a smaller minimum bend radius. Since Profax is non-conductive it enables a hose to be made that is non-conductive throughout. | |
Conductivity |
Many furnace hoses do not have conductivity requirements. Applications range from requiring high conductivity (usually a conductive tube and wire helix) to non-conductive (non-black, non-conductive tube and Profax (plastic) helix). In a very highly electrically charged environment, i.e. electric arc, electrodes and molten metal, a hose that is totally non-conductive is required to prevent grounding through the hose. As an example, a non-conductive hose will use SS nipples instead of carbon steel. | |
Handling |
Improper handling is storage and installation can be a source of damage. Storage in a non-heat environment, covered from dirt, and kept from harm's way is important. The hoses must not be handled in such a way that they "kink" as they are being installed or transported. The covers are susceptible to abrasion, tearing and gouging if not properly protected. | |
Life |
The primary cause of failure in a furnace hose is
from exposure to heat over a period of time. Although extreme radiant
heat is resisted by the protective covers, heat eventually can
and will cause degradation of the components. When molten slag
comes in contact with the hose the cover can char and burn unless
the cover is flame resistant. Heat resistance is not the same as
flame resistance. Nomex and Norfab fabrics on the hose cover can
degrade rapidly when in contact with flame and molten slag.
For maximum heat/flame resistance a fiberglass cover is recommended. A Silicone rubber layer over the fiberglass provides a smooth surface which resists molten slag from sticking. A Silicone/Fiberglass cover is recommended for “extreme” furnace applications. |
|
Cover Materials
Nomex |
Standard cover for furnace door hoses and supplied in 1, 2 or 3 ply. Rated at 600 deg F heat resistance; degrades when exposed to flame. |  |
Norfab |
A higher heat resistant cover material for furnace hoses supplied in 1 and 2 ply covers Rated at 700 deg F heat resistance; degrades when exposed to flame. |  |
Fiberglass |
Premium heat resistance in single or multiple ply covers up to 1,000 deg F. Does not burn when exposed to flame. |  |
Silicone |
An integral protective cover for Fiberglass hose constructions, providing a smooth surface to resist the slag from attaching itself, and enhances flame resistance. Silicone also protects the fiberglass hose during handling. Fiberglass has poor abrasion resistance, therefore, uniquely, the Silicone cover can be applied to the entire length of hose or to specific areas, i.e. one end only where the slag is the problem. |  |
Others |
In the industry wire braided covers, wire shields, fiberglass/Silicone sleeves are also used in some applications. | |