Wastewater Conveyance - Wastewater Operators - page 187

Cover

Wall thickness

Carcass

O.D. I.D.

Tu be

Reinforcing braid

Overall length

figure 4.17 Common hose nomenclature.

It is important to note that the flexibility of industrial hose is not
the only consideration that must be taken into account when selecting
hose over either piping or tubing; that is, hose must be selected accord-
ing to the potentially damaging conditions typical of a particular appli-
cation. These conditions include the effects of pressure, temperature,
and corrosion.

Hose applications include the use of lightweight ventilating hose
(commonly called elephant trunk ) to supply fresh air to maintenance
operators working in manholes, vaults, or other tight places. In waste-
water treatment plants, hoses are used to carry water, steam, corrosive
chemicals and gases, and hydraulic fluids under high pressure. To meet
such service requirements, hoses are manufactured from a number of
different materials.

4.11.1 hose nomenclature

To gain a fuller understanding of indus-
trial hoses and their applications, it is impor-
tant to be familiar with the nomenclature or
terminology normally associated with indus-
trial hoses. Accordingly, in this section, we
explain hose terminology that wastewater
operators should be familiar with. Figure 4.17 is a cutaway view of a
high-pressure air hose of the kind that supplies portable air hammers
and drills and other pneumatic tools commonly used in water/waste-
water maintenance operations. The hose is the most common type of
reinforced nonmetallic hose in general use. Many of the terms used in
the figure have already been mentioned. The I.D., which designates the
hose size, refers to the inside diameter throughout the length of the
hose body, unless the hose has enlarged ends. The O.D. is the diameter
of the outside wall of the hose.

Key Point: If the ends of an industrial hose
are enlarged, as shown in Figure 4.18, the
letters E.E. are used (meaning expanded
or enlarged end ). Some hoses have
enlarged ends to fit a fixed end of piping
tightly (e.g., an automobile engine).

As shown in Figure 4.17, the tube is the inner section (i.e., the core)
of the hose through which the fluid flows. Surrounding the tube is the
reinforcement material, which provides resistance to pressure—either
from the inside or outside. Notice that the hose shown in Figure 4.17
has two layers of reinforcement braid (fashioned from high-strength