1、E -1 1 _- * MIL-V-Z444A 13 m 7797906 03b0747 3 m MIL- V- 8 2444A (OS ) 29 June 1976 Superseding MIL-V-82444 (OS) 10 May 1966 MILITARY SPECIFICATION VALVE, FUEL TANK PRESSURIZATION This Specification has been approved for use by all Departments and Agencies of the Department of Defense. 1, SCOPE 1.1
2、Scope. This specification covers one type of fuel tank pres- surization valve referenced herein as the “valve.“ The valve is actuated by an electrically fired squib. 2. APPLICABLE DOCUMENTS 2.1 Applicable documents. The following documents of the issue % in effect on date of invitation for bids or r
3、equest for proposals form a part of this specification to the extent specified herein. STANDARDS Mi 1 i tary MIL-STD-105 MIL-sm-889 DRAWINGS Sampling Procedures and Tables for Inspection by Attributes Metals,Definition of Dissimilar Naval Sea Systems Command NAVSEA Dyg 2526708 Valve,Fuel Tank Pressu
4、rization, Specification Control Drawing (Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procuring functions should be obtained from the procuring activity or as directed by the contracting officer. ) Provided by IHSNot for ResaleNo
5、 reproduction or networking permitted without license from IHS-,-,-NIL- V- 82444A (OS) 3. REQUIREMEWS 3.1 Classification of requirements. The requirements for the valve are classified as follows: REQUIRWNT PARAGRAPH General requirements 3.2 Performance requirements and product characteristics 3.3 En
6、vironmental requirements 3.4 Operational service life 3.5 3.2 General requirements 3.2.1 Preproduction sample. Unless otherwise specified in the contract or purchase order, a preproduction sample of the valve shall be manufactured using the methods and procedures proposed for production, The sample
7、will be tested as specified in Section 4 herein and is for the purpose of determining, prior to starting production, that the contractors production methods are capable of yeilding items that comply with the technical requirements of the contract. 3.2.2 Materials 3.2.2.1 Materials and treatments of
8、materials. Unless otherwise Specified in the contract or purchase order, all materials and treat- ments of materials and parts used in the manufacture of the valve shall be in accordance with the applicable documents listed on NAVSEA Dwg 2526708. 3.2.2.2 Metals. Metals shall be of the corrosion-resi
9、stant type or shall be adequately protected to resist corrosion during the normal storage and service life of the valve. Unless suitably protected against electrolytic corrosion, dissimilar metals as defined in MIL-STD-889 shall not be used in intimate contact. 3.2.3 Definitions. Definitions of term
10、s appear in Section 6. 3.3 Performance requirements and product characteristics. Un- less otherwise specified, the valves shall satisfy the following per- formance requirements when tested as specified in Section 4: 3.3.1 Leakage at proof pressure. The valve shall be capable of with- standing a maxi
11、mum internal pressure of 4500 pounds per square inch gage (psig) without leaking and without sustaining permanent distortion. o Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-82444A (OS) 3.3.2 Leakage at operating pressure, after firing. After
12、 firing, with the squib remaining in the valve body, the valve shall be capable of with- standing an internal operating pressure of 4500 psig when pressure is applied to the inlet and outlet pats. -, 3.3.3 Squib bridge wire resistance, before firing. The electrical circuit of the bridge wire of all
13、squibs, whether separate or assembled into the valve, shall be continuous and shall have a total resistance of not less than 0.6 ohm nor more than 1.2 ohms, before firing, when measured at a current of 0.01 ampere maximwn. 3.3.4 Insulation resistance, valve, before firing. The insulation resist- anc
14、e between the pins of the valve electrical connector and valve case shall be 2 megohms minimum before firing when measurement is made using a potential of 500 volts root-mean-square (rms) at 60 Hertz (Hz). 3.3.5 Insulation resistance, squib, before firing. The insulation resist- ance between the lea
15、ds of the squib bridge wires and the squib case shall be 2 megohms minimum before firingwhen measurement is made using a potential of 500 volts nns at 60 Hz. 3.3.6 Auto-ignition 3.3.6.1 Low temperature. The squibs, whether separate or assembled into the valve body, shall be capable of withstanding a
16、 temperature of +170 F for 2 hours and shall not self-ignite. operating requirements of 3.3.8. Thereafter, the squib or valve shall meet the 3.3.6.2 High temperature. The squibs, whether separate or assembled into the valve body, shall be capable of withstanding a temperature of +200F for 8 hours an
17、d shall not self-ignite. Thereafter, the squib, or valve, is not required to meet the operating requirements. 3.3.7 No-fire current. The squib, whether separate or assembled into the Thereafter, valve body, shall be capable of having a current of 0.2 ampere dc passed through its bridge wire for 5 mi
18、nutes minimum without igniting. the squib shall be capable of meeting the operating requirements of 3.3.8. 3.3.8 Firing current. The squib, whether separate or assembled into the valve body, shall fire when subjected to a current of 2 amperes dc for 5 milliseconds. 3 Provided by IHSNot for ResaleNo
19、reproduction or networking permitted without license from IHS-,-,-MI L- V- 8 2444A (OS ) Double Amplitude Acceleration Frequency (in. +- 10%) Minimum (gvn f io) Minimum 5 - 22 3.0 22 - 40 40 - 74 o. 2 - 0.036 - - 10 74 - 500 - d * 3,3.9 Flow, after firine;. Upon actuation, the ram shall completely s
20、ever the integral metal diaphragm permitting full flow through the valve. cubic feet per minute of dry gaseous nitrogen with 300 +5 psig applied to the inlet at 70 f5F. The opening shall be capable of flowing a minimum of 5 standard 3.3.10 Configuration 3.3,lO.l Dimensions. Dimensions of the valve s
21、hall be in accordance with the NAVSEA Dwg 2526708 and all documents listed thereon. 3.4 Environmental requirements. Unless otherwise specified, the valve shall be capable of conforming to the performance requirements and product characteristics of the specification after being exposed to the environ
22、mental conditions specified in this section. For definitions of ready, operating, and nonoperating see 6.3.1, 6.3.2, and 6.3.3. 3.4.1 Vibration, ready condition. The valve, mounted as shown in Figure 1, shall be capable of meeting the performance requirements after being subjected, in the ready cond
23、ition, to the vibrations defined in Table I. The valve shall be vibrated for 180 minutes each in its longitudinal axis and in two mutually perpendicular transverse axes at any temperature within the range of -45“ F to +140“ F. Vibration is defined in 6.3.4. TABLE I VIBMTION SCHEDULE 4 Provided by IH
24、SNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1 . MIL-V-82444A 13 797770b 03b0751 5 W Acce rat n Dir tion 25 Longitudinal axis, with an accuracy to +5“ F b. Relative humidity: 95 percent minimum at +llOo F; with an accuracy to +5“ F e. Interior size: 6 inches x
25、4 inches x 3 inches minimum This equipment may be used for both nonoperating and ready/operating temp- erature (and humidity) tests. 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-82VVVA li3 - 9999906 0360956 4 P 1 2 3 4 Number of Resonances
26、 0 Total Vibration Time at Resonance * - 30 min 1 hr 1-k hr 2 hr Cycling Time 3 hr 24 hr 2 hr l-% hr 1 hr c MIL-V-82444A (OS) 4.4.4 Test procedures 4.4.4.1 Inspection, The valve shall be subjected to the inspections, . prior to firing, detailed in 4.5,6.1 through 4.5.6.4. * 4.4.4.2 Auto-ipnition, lo
27、w temperature. The valve (or sample squib) shall be heated in air to a temperature of +170 F 42 F and maintained at that temperature of 2 hours. fire. meeting the requirements of 4.4,4.11, The valve (or sample squib) shall not Thereafter, the valve (or sample squib) shall be capable of 4.4.4.3 Auto-
28、ignition, high temperature, The valve shall be heated in air to a temperature of +200 F +lo“ F and maintained at that temperature for 8 hours. The valve shall not fire. valve shall not be required to meet the operating characteristics: Thereafter, the 4.4.4.4 Vibration, ready condition, The valve, i
29、n the ready condition, shall be mounted in a manner equivalent to that shown in Figure 1. The resonant modes in each of the 3 axes shall be determined by varying the frequency of applied vibration slowly from 5 Hz to 500 Hz, shall then be subjected to resonance and cycling vibration in each axis, in
30、 conformance with the times shown in Table V. are encountered on any axis, the 4 for the test. divided into 3 equal parts, which are conducted at -45“ F t-5 F, room temperature and +140“ F 25“ F respectively. frequency sweep rate shall be used if avaiable; otherwise, other cycling rates of frequency
31、 change may be used. The sweep rate shall be such that 15 minutes actual vibration time is required to proceed from the lower to higher and back to the lower extremity of frequency range in accordance with the accelerations or double amplitudes defined in Table VI. The valve If more than 4 resonance
32、s most severe resonances shall be chosen The resonant and cycling period, for each axis, shall be For cycling, a logarithmic TABLE V VIBMTION TEST SCHEDULE 10 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-V-B2LI44A 13 7777706 0360757 6 Magnitu
33、de (gs f 10%) MIL-V-82444A (OS) TABLE VI Time Acceleration Direction (see Figure 1) VIBRATION SCHEDULE Frequency (Hz) Double Amplitude Acceleration (in. e 10%) Minimum (gs f 10%) Minimum 5-22 0.2 - 4.4.4.5 Acceleration, ready condition. The valve, in the ready cond- ition, shall be subjected to the
34、accelerations defined in Table VI1 after being secured to an acceleration equipment (see Figure 1). Acceleration shall be measured at the approximate geometric center of the valve. TABLE VI1 ACCELERATION SCHEDULE 25 35 Longitudinal axis, Fwd 1 Minute .Longirudinal axis, Aft I 1 Minute I I .- 4.4.4.6
35、 Shock. ready condition. The valve, in the ready condition, shall be attached to a shock test machine (see Figure 1). tudes and durations shall be measured by an accelerometer mounted on the mounting fixture. with Table VI11 in the sequence shown. Shock magni- Tests on the valve shall be performed i
36、n accordance 11 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-V-82444A 13 997790b 0360758 = MIL-V- 82444A (OS) TABLE VI11 SHOCK TEST SCHEDULE I Test equence 1 2 3 4 5 6 7 8 Peak bgni tude ;Es -I 10%) 300 85 85 45 60 60 60 60 Duration (ms 1 0.5
37、 to 1.5 0.5 to 1.5 0.5 to 1.5 18.0 to 20.0 8.0 to 10.0 8.0 to 10.0 8.0 to 10.0 8.0 to 10.0 _L_- Impack Axis Longitudinal Transverse A Transverse B Longitudinal Longitudinal Longitudinal Transverse A Transverse B lirection of leceleration Forca Aft Op ti ona 1 Opt ional Fwd Aft Fwd Optional Optional
38、- Number Impacts Of 4.4.4.7 Temperature and humidity, nonoperatinp condition. Four preproduction valves shall be subjected, in the nonoperating condition, to temperature and humidity cycling in the following manner: The specimen shall be placed in a temperature chamber which has been stab- ilized at
39、 an environmental temperature of -45“ F +Oo -5“ F. The specimen shall remain in the environment for 6 hours. (As an alternative procedure, the specimen may be placed in the chamber, with the chamber at room ambient temperature. Chamber temperature shall then be reduced to -45“ F +Oo -5“ F within 2 h
40、ours maximum. for 4 hours). temperature of +140“ F +5“ F -0“ F. Maximum transition time from the low temperature to the high temperature shall be 2 hours. shall remain in the high temperature environment for 4 hours. This cycle shall be performed 3 times; maximum transition time shall be 2 hours. sp
41、ecimen shall subsequently be subjected to an environment of +llOo F +5“ -Oo F at a minimum relative humidity of 95 percent for a minimum of 8 hours. Thereafter, 2 valves shall be operated in accordance with 4.4.4.8 and 2 valves shall be operated in accordance with 4.4.4.9. operation the valves may b
42、e wiped dry. Drying by an air blast or oven is not permit ted. The specimen shall thereafter remain in the chamber The specimen shall then be subjected to an environmental The specimen The Prior to * 4.4.4.8 Low temperature operatinK. Before testing, the valve, installed in its test chambler in the
43、ready condition, shall be condit- ioned at a temperature of 0 F k5O F for a period of 1 hour. The valve shall then 4.4.4.11 at an environmental temperature of +3Z0 F 4 5O F. The valve shall thereafter meet the requiements of 4.4.4.12 through 4.4.4.14. be operated in accorance with and meet the requi
44、rements of 12 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-82444A 13 m 999990b 0360959 T m * 4.4.4.9 High temperature operating, Before testing, the valve, installed in its test chamber in the ready condition, shall be condi- tioned at a tem
45、perature of +140“ F f5 F for a period of 1 hour. The valve shall then be operated in accordance with and meet the requirements of 4.4.4.11 at an environmental temperature of +140F f5“ F. The valve shall thereafter meet the requirements of 4.4.4,12 through 4.4.4.14. 4.4.4.10 No-fire current. The valv
46、e (or sample squib) shall be sub- jected to a current of 0.2 40.02 ampere maximum for a period of 5 minutes minimm, in accordance with Figure 2, and shall not fire. Thereafter, the valve (or sample squib) shall be capable of meeting the requirements of 4.4.4.11. 4.4.4.11 Firin6 current. The valve (o
47、r sample squib) shall fire when subjected to a current of 2.0 rC0.2 ampere dc for 5 10.5 milliseconds in accordance with Figure 2, 4.4.4.12 Visual inspection, after firing. After firing, the valve case shall be inspected and shall show no evidence of permanent distortion, * 4.4.4.13 Flow, after firi
48、ng. Upon actuation, the ram shall completely sever the integral metal diaphragm permitting full flow through the valve, e flow through the actuated valve shall be at least 5 standard cubic feet per minute of dry gaseous nitrogen with 300 k5 psig applied to the inlet at 70 f5“F. 4.4.4.14 Leakage at o
49、perating pressure, inlet and outlet ports, after With the squib remaining in the valve body after firing, the firing. valve shall be subjected to a pressure of 4500 f200 psig, using dry inert gas. a period of 5 minutes with the valve submerged in water. no evidence of leakage. inspected for evidence of permanent distortion. Pressure shall be applied to the inlet and outlet ports for There
