NOTE: Adjustments, which change the integrity of the tubing assembly, are not permitted. The sealing surface of a tube must never be drawn to a fitting with the tubing nut.
(2)
Lubricate male threads and back sides of tubing nuts with oil (MIL-L-7808) or (MIL-L-23699) lubricant.
NOTE: Apply lubricants to male fitting only. Avoid line or sealing surface contamination with lubricant.
(3)
Engage threads with fingers before tightening.
NOTE: If requirement cannot be met, parts shall remain rejected until reworked or replaced.
(4)
Uniformly increase torque until the required torque is obtained.
CAUTION: DO NOT OVER-TORQUE TUBING OR CONNECTIONS AS A MEANS TO CORRECT LEAKS OR MISALIGNMENT.
(a)
On tubing and connection fittings run the nut down to the required torque.
(b)
On flared-type fittings, back off one-quarter turn, then retighten to the required torque.
(c)
Where gaskets set slowly, briefly hold fitting at torque until the gasket has set.
CAUTION: DO NOT OVER-TORQUE TUBING OR CONNECTIONS AS A MEANS TO CORRECT LEAKS OR MISALIGNMENT.
(5) Apply final tightening of nuts to the required values using the following guideline. Values for aluminum alloy tubing shall apply in the following situations:
NOTE: Defective fittings are normally disassembled, checked, and replaced.
.
Aluminum alloy tubing is used with steel fittings.
.
Aluminum alloy threaded parts are mated with steel threaded parts.
.
Steel tubing is used with aluminum alloy fittings.
(6) For flared tube fittings 1.5 inch (38,1 mm) or larger eliminate sleeve bind-up on the tube during tightening.
(a)
After tightening, back off nut and check sleeve for rotation.
(b)
If the sleeve rotates, it is not defective. Final tighten the nut.
Assembly
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(7) Assemble flared tubing and hose fitting connection. Refer to Figure 504.
(a) Identify the required torque value.
.
For flared tubing or hose fitting connections (except conical seals) refer to Table 510.
.
For fluid fittings used with ring seals or gaskets made of aluminum, asbestos, leather, or other similar types of material refer to Table 511 and Table 512.
.
For special metal seals tighten as specified. Refer to assembly manuals.
WARNING: DO NOT OVER-TORQUE ADJOINING FITTINGS OR DAMAGE MAY OCCUR.
(b) Hold fittings and hose assembly nuts securely (see Figure 504) while applying specified torque.
Flared Tubing and Hose Fitting Connections
Figure 504
Assembly
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(8) Assemble flareless tubing assembly.
(a)
Align assemblies so that tube ends are square with adjoining fittings.
(b)
Lightly lubricate male threads of adjoining fittings with oil (MIL-L-7808) or (MIL-L-23699) lubricant.
NOTE: Allow the brackets that secure the tube assembly to the basic unit to remain loose until the tubing fittings are torqued.
(c)
Install nut by hand until it engages the threads of male fitting and contacts sleeve.
(d)
Tighten the nut on the coupling to the specified torque value.
.
Tighten the nut on dynamic beam seal couplings in accordance with Table 513.
.
Tighten the nut on flareless tube couplings in accordance with Table 514.
Table 510. Flared Tubing and Hose Fittings Tightening Specifications
Assemble with Lubricants According to Table 503. ALL STEEL PARTS
TUBE OD (INCH) TUBE DASH NO. THREAD SIZE (IN-LBS) (N-m)
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本文链接地址：标准施工手册 STANDARD PRACTICES MANUAL 20-00-02/70-00-01(112)
