Page 275 - untitled

Parker Hannifin Corporation

Parflex Division

Ravenna, Ohio

269

Coiled Air Hose,

Fittings

& Accessories

Hydraulic &

Pneumatic

Hose & Fit.

PTFE

Hose &

Fittings

The

rmoplastic

Tu

bing

Truck (Fleet)

Products

Tooling &

Equipment

Hose

Accessories

Technical &

Design

Information

Approvals &

Guides

Alphanumeric

Index

Selection, Installation & Maintenance

5.14 Hose Fittings –

Selection of the proper hose fittings for

the hose and application is essential for proper operation

and safe use of hose and related assembly equipment. Hose

fittings are qualified with the hose. Therefore, select only hose

fittings compatible with the hose for the applications.

Improper selection of hose fittings or related assembly

equipment for the application can result in injury or damage

from leaks, or from hose assemblies blowing apart (see 4.2,

6.2, 6.3 and 6.4).

5.15 Vibration –

Vibration can reduce hose service life. If

required, conduct tests to evaluate the frequency and

amplitude of system vibration. Clamps or other means may be

used to reduce the effects of vibration. Consider the

vibration requirements when selecting hose and predicting

service life.

5.16 Hose Cover Protection –

Protect the hose cover from

abrasion, erosion, snagging and cutting. Special abrasion-

resistant hoses and hose guards are available for additional

protection. Route hose to reduce abrasion from hose rubbing

other hose or objects that may abrade it.

5.17 External Physical Abuse –

Route hose to avoid:

A.

Tensile loads

B.

Side loads

C.

Flattening

D.

Thread damage

E.

Kinking

F.

Damage to sealing surfaces

G.

Abrasion

H.

Twisting

5.18 Swivel-Type Adapters –

Swivel-type fittings or adapt-

ers do not transfer torque to hose while being tightened. Use

these as needed to prevent twisting during installation.

5.19 Live Swivels –

If two components in the system are

rotating in relation to each other, live swivels may be

necessary. These connectors reduce the torque transmitted to

the hose.

5.20 Slings and Clamps –

Use slings and clamps to support

heavy or long hose and to keep it away from moving parts. Use

clamps that prevent hose movement that will cause abrasion.

5.21 Minimum Bend Radius –

The minimum bend radius is

defined in SAE J343 and is specified in other SAE standards

and hose manufacturer's product literature. Routing at less

than minimum bend radius may reduce hose life. Sharp bend-

ing at the hose/fitting juncture may result in leaking, hose

rupturing, or the hose assembly blowing apart (see 4.2 and

Figure 1).

FIGURE 1 — MINIMUM BEND RADIUS

5.22 Elbows and Adapters –

In special cases, use elbows and

adapters to relieve hose strain (see Figure 2).

Incorrect

Correct

FIGURE 2 — ELBOWS AND ADAPTERS

5.23 Lengths –

Unnecessarily long hose can increase pres-

sure drop and affect system performance. When pressurized,

hose that is too short may pull loose from its fittings, or stress

the fitting connections, causing premature metallic or seal

failures. When establishing hose length, refer to Figures 3, 4,

and 5; and use the following practices:

5.23.1 Motion Absorption –

Provide adequate hose length

to distribute movement and prevent bends smaller than the

minimum bend radius.

FIGURE 3 — MOTION ABSORPTION

5.23.2 Hose and Machine Tolerances –

Design hose to

allow for changes in length due to machine motion and

tolerances.

FIGURE 4 — HOSE AND MACHINE TOLERANCES

5.23.3 Hose Length Due To Pressure –

Design hose to ac-

commodate length changes from changing pressures. Do not

cross or clamp together high- and low-pressure hoses. The

difference in length changes could wear the hose covers.

FIGURE 5 — HOSE LENGTH DUE TO PRESSURE

Incorrect

Correct

Incorrect

Correct

Incorrect

Correct