1、MIL-H-22577C 9 September 1982 SUPERSEDING MIL-H-22577B 20 September 1971 (See 6.4) MILITARY SPECIFICATION HEATING ELEMENTS, ELECTRICAL: CARTRIDGE, STRIP AND TUBULAR TYPE This specification is appEoved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This spec
2、ification covers electrical heating elements used in various electrically heaced equipment (for example: immersion heaters for water or oil, cooking equipment, hospital equipment and space heaters). Heat- ing elements of these types are commonly used in industrial and domestic appli- cations. Except
3、 where conflicts exist, industrial and commercial standards may be applied. 1.2 Classification. Heating elements shall be of the following types, as specified (see 6.2). Type I - Cartridge Type II - Strip Type III - Tubular 2. APPLICABLE DOCUMENTS * 2.1 Government documents. * 2.1.1 Specifications a
4、nd standards. Unless otherwise specified, the followng specifications and standards of the issue listed in that issue of the Department of Defense Index of Specifications and Standards (DoDISS) speci- fied in the solicitation form a part of this specification to the extent speci- fied herein. - Bene
5、ficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 5523, Department of the Navy, Washington, DC 20362 by using the self-addressed Standardization Document Impr
6、ovement Proposal (DD Form 1426) appearilig at the end of this document or by letter . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SPECIFICATIONS MILITARY MIL-E-9 17 - Electric Power Equipment, Basic Requirements MIL-E-17555 - Electronic and Elect
7、rical Equipment, Accessories, (Naval Shipboard Use). and Repair Parts; Packaging and Packing of. STANDARDS MILITARY MIL-STD-105 - Sampling Procedures and Tables for Inspection by DOD-STD-1399, - Interface Standard for Shipboard Systems Electric Attributes. Section 300 Power, Alternating Current (Met
8、ric). (Copies of specifications and standards required by contractors in con- nection with specific acquisition functions should be obtained from the con- tracting activity or as directed by the contracting officer.) k 2.2 Other publications. The following documents form a part of this specification
9、 to the extent specified herein. The issues of the documents which are indicated as DoD ad-opted shall be- the issue listed in the current DoDISS and the supplement thereto, if applicable. AMERICAN SOCIETY FOR TESTING AND MATERIALS (AS“) B 163 - Seamless Nickel and Nickel Alloy Condensor and Heat- B
10、 344 - Drawn or Rolled Nickel - Chromium and Nickel-Chromium- B 456 - Electrodeposited Coatings of Copper Plus Nickel Plus Exchanger Tubes. (DoD adopted) Iron- Alloys for Electrical Heating Elements. . Chromium and Nickel Plus Chromium. (Application for copies should be addressed to the American Soc
11、iety for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) (Industry association specifications and standards are generally available for reference from libraries. They are also distributed among.technica1 groups and using Federal agencies.) 1 2.3 Order of precedence. In the event of
12、 a conflict between the text of this specification and the references cited herein, the text of this specification shall take precedence. 3. REQUIREMENTS 3.1 Material. 3.1.1 Material not specified herein shall be selected on the basis of meeting the performance requirements of this specification at
13、minimum cost. rk 3.1.2 Resistance wire. Resigtance wire shall be nickel-chromium wire conforming to composition 60Ni-16Cr or 80Ni-20Cr of ASTM B 344. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-H-22577C 3.1.3 Insulating material. Granular ins
14、ulating material shall be high purity magnesium oxide and shall be densely packed. Insulating material for formed parts, such as spacers, cores or bushings shall be high quality electri- cal grade ceramic of high thermal conductivity, high nsulation resistance and formulated for physical strength. 3
15、.1.4 Sheath materials. Sheath materials shall be corrosion-resisting in the surrounding mdium.and suitable for the tsmperatures required by a particular application. Table I shall be used as a guide. * TABLE I. Recommended sheath materials for various applications and temperatures. Sheath material C
16、opper Nickel-chromium-plated copper Steel Nickel-copper alloy Nickel-silver Chrome-steel Corrosion-resisting steel Nickel-iron-chromium alloy21 Nickel-chromium-iron alloya (Incoloy) UNS N08800 (Inconel) UNS N06600 Maximum shea th temperature OFY 350 350 750 900 1000 1200 1200 1500 1600 L/ Operation
17、above 1000 degrees Fahrenheit (F). for end sealed units is not permitted Applications : A - Water immersion B - Oil immersion C - Cast-in-metal D - Contact metal heating E - Air heating 3/ See ASTM B 163. * 3.1,4.1 Nickel-chromium plating. Nickel-chromium plating of sheaths shall be in accordance wi
18、th ASTM B 456, classification Cu/Ni30d Cr r. * 3.1.5 Asbestos. Asbestos shall not be used. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-H-225776 * 3.1.6 Recovered materials. Unless otherwise specified herein, all equipment, material, and art
19、icles incorporated in the products covered by this specification shall be new and shall be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing the intended use. The term “recovered materials“ means materials which have been collected or
20、 recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. None of the above shall be interpreted to mean that the use of used or rebuilt products is allowed under this specification unless.otherwise specifically specified. 3.2 Type I, cartri
21、dge. 3.2.1 Description. Type I heating elements are metal-sheathed heating elements, round in cross-section, either closed at one end with terminals or lead wires at the opposite end, or terminals at both ends. The sheath encloses resistance wire which shall be carefully positioned in the insulating
22、 material. Cartridge type elements are not suitable for bending or forming. 3.2.2 Terminal construction. The terminal end of the heating element shall be constructed so as to minimize the entrance of atmospheric moisture into the heating element. The terminal construction shall be suitable for the a
23、pplication, temperature and atmospheric conditions present. -Unless a hermetic, or other special type seal is specified (see 3.5 and 6.2), the terminal design and materials shall be as selected by the manufacturer to satisfy the require- ments of a particular application. The type of connection, eit
24、her threaded terminal studs or flexible leads of high temperature wire, shall be as specified (see 6.2). Nuts and lockwashers for making conneFtions shall be furnished .with heating elements having threaded terminal studs . Where provided, flexible leads shall be at least 10 inches long. * 3.2.3 Ins
25、ulation resistance, cold. Each heating element shall have a minimum insulation resistance of 25 megohms at room temperature. * 3.2.4 Insulation resistance, hot. Each heatiqg element shall have a minimum insulation resistance of 10 megohms at the maximum operating temperature for the sheath material
26、(see 3.1.4 and 6.3.2) or actual operating temperature for the element (see 6.2). For heating elements whose maximum operating temper- ature is in excess of 1000F, the hot resistance may be tested with its entire system in accordance with MIL-E-917 as outlined in 4.3.6 of this specification. 3.3 Type
27、 II, strip. 3.3.1 Description. Type II heating elements are metal-sheathed heating elements, usually rectangular in cross-section with terminals projecting through the sheath, perpendicular to one major plane surface of the sheath. The sheath shall enclose helically coiled resistance wire uniformly
28、spaced over the length and width of the element. Mounting slots or holes shall be provided at both ends of the heating element. Heating elements shall be suitable for lengthwise bending by the manufacturer to a minimum inside radius of 8 inches. Location and description of bends, if desired,.shall b
29、e as specified (see 6.2). Strip type elements are not designed for use as immersion heaters and are not recommended for , use in moist or humid locations or where terminals are located in an air stream. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,
30、-MIL-H-22577C q5-W 797790b 0233537 b MIL-H-22577C 3.3.2 Terminal construction. Terminals shall be of the threaded stud type and be designe examples of which are: (a) Mounting bushings, screw plug or mounting flanges to facilitate (b) Fins (for forced air heaters). sealing cartridge or tubular heater
31、s in tank walls and so forth. 3.6.1 Parts such as bushing, flanges, or fins shall be securely brazed to the heating element sheath. 3.7 Wattage. The wattage of the heating element at rated voltage shall be within the range of plus 5 to minus 10 percent of that specified (see 6.2). * 3.8 Voltage. The
32、 operating voltage shall be either 440 or 115 V in accord- ance with DOD-STD-1399, section 300, as specified (see 6.2). The element shall operate satisfactorily on voltages up to 105 percent of the specified rating. When heating elements are intended for operation on a voltage other than line voltag
33、e (by series or wye connections), the line to line voltage shall also be specified. The heating element shall be insulated for the line voltage and shall have electrical creepage and clearance dhensions for line voltage. 3.9 Dielectric strength. Heating elements shall withstand a dielectric test of
34、twice rated line voltage plus 1000 for a period of 1 minute. The voltage wave.shal.1 approximate a sine wave and the frequency shall be not less than 60 hertz. 3.10 Descriptive information. The following information, shall be as specified (see 6.2). (a) Sheath material. (b) Sheath diameter or cross-
35、section dimensions. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-(c) Length of heated portion of element. (d) Length of sheath. (e) Overall length of element. (f) Location and description of bends, if required-for strip or tubular elements. (g)
36、Details of special features such as length of finned portion, fin diameter, distance between flanges of mounting bushings, sizes of mounting bushings, flanges, and so forth. specified shall be as relaxed as application permits. The manu- facturers normal manufacturing tolerances shall apply if no li
37、mits are specified. turer select the heating element to best suit the particular application. This shall include data on material to be heated, rate of heating, air velocities, dimensional limitations and so forth. (h) Dimensional and bending tolerances, if critical. Tolerances, if (i) Application d
38、ata, if it is desired that the heater manufac- 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the contractor is responsible for the performance of all inspection requirements as specified herein. Except as otherwise sp
39、ecified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requiremhts specified herein, unless disapproved by the Government. The Government reserves the right to perform any of the inspections set forth in the sp
40、ecification where such inspections are deemed necessary to assure supplies and services conform. to prescribed requirements. 4.2 Quality conformance inspection. 4.2.1 Inspection lot. All heating elements of the same power rating and type, and made for the same application (see 3.1.41, and offered fo
41、r delivery at one time shall be considered a lot for purposes of sampling and inspection. 4.2.2. Sampling. Sample heating elements shall be selected from each lot in accordance with inspection level II of MIL-STD-105 and each of these elements shall be subjected to each of the examinations and tests
42、 specified in 4.3.1, 4.3.2, 4.3.3, 4.3.4 and 4.3.5, and- the results of each test shall be compared with the requirements of this specification. Failure to conform to this specification for any of the examination or tests shall be counted as a defect and the heating element shall not be offered for
43、delivery. The acceptable quality level (AQL) for lots shall be 1.5 percent defective. 4.2.3 Sampling for insulation resistance (hot) tests. Sample elements shall be selected from each lot in accordancewith inspection level S-4 of MIL-STD-105 and shall be subjected to the test of 4.3.6. If any elemen
44、t fails this test, it shall not be offered for delivery. Lots shall be accepted or rejected in accordance with AQL 4.0 percent defective. 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-H-22577C 4 . 3 Test procedures . 4.3.1 Dimensions, materia
45、ls, and workmanship. Each of the heating ele- ments shall be subjected to a thorough visual and dimensional examination to - ascertain that the materials, workmanship, design and dimensions conform to this specification. 4.3.3 Moisture resistance (elements having hermetically sealed terminals onlv).
46、 Where hermetically sealed terminals are required, each element shall be &nersed in water for i0 mizutes and the terminals wiped dry prior to the dielectric test of 4.3.4 and the insulation resistance .test af 4.3.5. 4.3.4 Dielectric strength. The heating element shall be subjected to and shall with
47、stand for a period of 1 minute, a dielectric test voltage of twice the rated line voltage plus 1000 V applied between the terminal and the sheath as specified in 3.9. The test shall be conducted with the heating element at normal room temperature. * 4.3.5 Insulation resistance, cold. The insulation
48、resistance shall be measured with 500 V direct current (d.c.) at room temperature to determine compliance with 3.2.3, 3.3.3 or 3.4.3. * 4.3.6 Insulation resistance , hot. The insulation resistance shall be measured with a minimum of 500 V d.c. wfthin 5 seconds after operation of the element at maxim
49、um operating temperature for the sheath material (see 3.1.4) , or end seal material. (see 3.5), or operating temperature of the element (see 6.2),.whichever is the least, to determine conformance with 3.2.4, 3.3.4, or 3.4.3. To prevent the element from being cooled before the test, the ambient fluid shall not be circulated after the power -is removed. Heating elements with operating temperatures above lOOOOF may be tested in the heater. 4.4 Inspection of p
