1、MIL-C-24746 41 = 9999906 0469811 IINCH-POUNDI MIL-C-24746(SH) 31 December 1990 MILITARY SPECIFICATION COOLERS, UNIT FORCED AIR FOR SHIPS REFRIGERATED STORES This specification is approved for use by the Naval Sea Systems Command, Department of the Navy, and is available for use by all Departments an
2、d Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification describes forced air unit coolers for use in food storage chill and freeze rooms on board Naval ships. 1.2 Classification. Unit coolers shall be of the following sizes and capacities (see 3.4 and 6.2): Standard size Stan
3、dard capacity (tons) I II III IV V VI VI I 2. APPLICABLE DOCUMENTS 1/8 1/4 3/8 1/2 3/4 1 - 1/2 1 British thermal units per hour (Btu/hr) 1,500 3,000 4,500 6,000 9,000 12,000 18,000 2.1 Government documents. 2.1.1 Specifications, standards, and handbooks. The following speci- fications, standards, an
4、d handbooks form a part of this document to the extent specified herein, those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and supplement thereto, cited in the solicitation (see 6.2). Unless otherwise specified, the issues of these documents are Be
5、neficial 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 20362-5101 by using the self-addressed Standardization Docume
6、nt Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A FSC 4110 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SPECIFICATI
7、ONS FEDERAL BB-F-1421 - Fluorocarbon Refrigerants. QQ - B - 6 54 - Brazing Alloys, Silver. PPP-F- 320 - Fiberboard: Corrugated and Solid, Sheet Stock (Container Grade), and Cut Shapes. MILITARY MIL-S-901 MIL- E - 9 17 MIL-P-15024 MIL-P-15024/6 MIL-P-15280 MIL-R-16743 MIL-M-17059 MIL-L-19140 MIL-E-19
8、933 MIL-E-22200/2 MIL-H-22577 MIL-V-23450 MIL-E-24142 MIL-P-24423 DOD-G-24508 MIL-R-46089 MIL-C-81302 MIL-T-81955 - Shock Tests, H.I. (High-Impact) Shipboard Machinery, Equipment, and Systems, Requirements for. - Electric Power Equipment, Basic Requirements (Naval Shipboard Use). - Plates, Tags and
9、Bands for Identification of Equipment. - Plates, Identification, Equipment. - Plastic Material, Unicellular (Sheets and Tubes). - Refrigerating Plants and Systems, Mechanical; and Refrigeration System Components - Dichlorodi- fluoromethane Type-12 - Naval Shipboard. - Motors, 60-Cycle, Alternating-C
10、urrent, Fractional H.P. (Shipboard Use). - Lumber and Plywood, Fire-Retardant Treated. - Electrodes and Rods - Welding, Bare, Chromium and - Electrodes, Welding, Covered (Austenitic Chromium- - Heating Elements, Electrical: Cartridge, Strip and - Valves, Expansion, Thermostatic, Refrigerant 12 and -
11、 Enclosures For Electrical Fittings and Fixtures, - Propulsion and Auxiliary Control Consoles and Chromium-Nickel Steels. Nickel Steel). Tubular Type. Refrigerant 22. General Specification For. Associated Control and Instrumentation Equipment, Naval Shipboard Use, Basic Design Requirements. - Grease
12、, High Performance, Multi-Purpose. (Metric) - Rubber, Sponge, Silicone, Closed Cell. - Cleaning Compound, Solvent, Trichloro- - Tin Plating; Immersion for Copper and Copper trifluoroethane. Alloys. STANDARDS MILITARY MIL-STD-167-1 - Mechanical Vibrations of Shipboard Equipment (Type I - Environmenta
13、l and Type II - Internally Excited). - Welding and Brazing Procedure and Performance Qualification. MIL-STD-248 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-24746 43 7977706 0467833 1i MIL-C-24746(SH) MILITARY (Continued) MIL-STD-278 MIL-S
14、TD-740-1 Criteria of Shipboard Equipment. MIL-STD-740-2 - Structureborne Vibratory Acceleration Measurements and Acceptance Criteria of Shipboard Equipment. MIL-STD-785 - Reliability Program for Systems, and Equipment Development and Production MIL-STD-889 - Dissimilar Metals. MIL-STD-1186 - Cushion
15、ing, Anchoring, Bracing, Blocking and MIL-STD-1399, - Interface Standard for Shipboard Systems Ship MIL-STD-2073-1 - DoD Materiel Procedures for Development and - Welding and Casting Standard. - Airborne Sound Measurements and Acceptance Waterproofing; with Appropriate Test Methods. Section 301 Moti
16、on and Attitude. (Metric) Application of .Packaging Requirements. (Unless otherwise indicated, copies of federal and military specifications, standards, and handbooks are available from the Standardization Documents Order Desk, Bldg. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094,) 2.1.2 Other
17、Government documents, drawinvs. and Dubiications. The following other Government documents, drawings, and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation. DRAWING NAVAL SEA SYSTEMS COMMAND (NAVSEA) 8
18、03-6397311 - Standard Dimensions for Coolers Forced Air Unit Type for Ships Refrigerated Stores. (Application for copies should be addressed to: Commander, Portsmouth Naval Shipyard, Naval Engineering Drawing Support Activity, Code 202.2, Portsmouth, NH, 03804-5000.) PUBLICATION NAVAL SEA SYSTEMS CO
19、MMAND (NAVSEA) 0900-LP-001-7000 - Fabrication and Inspection of Brazed Piping Systems. (Application for copies should be addressed to the Standardization Documents Order Desk, Bldg. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.2 Non-Government Dublications. The following document(s) form
20、a part of this document to the extent specified herein. issues of the documents which are DOD adopted are those listed in the issue of the DODISS cited in the solicitation. documents not listed in the DODISS are the issues of the documents cited in the solicitation (see 6.2). Unless otherwise specif
21、ied, the Unless otherwise specified, the issues of 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-24746 41 = 9999906 0469834 3 AIR MOVEMENT AND CONTROL ASSOCIATION (AMCA) Bulletin 210 - Laboratory Methods of Testing Fans for Rating. (Applica
22、tion for copies should be addressed to Air Movement and Control, Inc., 30 West University Drive, Arlington Heights, IL 60004.) AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) A 240 - Standard Specification for Heat-Resisting Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip For
23、Pressure Vessels. (DoD adopted) Stainless Steel Tubing for General Service. (DoD adopted) A 276 - Standard Specification for Stainless and Heat-Resisting Steel Bars and Shapes. A 366 - Standard Specification for Steel, Sheet, Carbon, Cold- Rolled, Commercial Quality. (DoD adopted) A 789 - Standard S
24、pecification for Seamless and Welded Ferritic/ Austenitic Stainless Steel Tubing for General Service. B 68 - Standard Specification for Seamless Copper Tube, Bright Annealed. B 88 - Standard Specification for Seamless Copper Water Tube. (DoD adopted) B 108 - Standard Specification for Aluminum Alloy
25、 Permanent Mold Castings. (DoD adopted) B 111 - Standard Specification for Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock. (DoD adopted) B 209 - Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate. B 395 - Standard Specification for U-Bend Seamless Copper and C
26、opper Alloy Heat Exchanger and Condenser Tubes. (DoD adopted) D 3951 - Standard Practice for Commercial Packaging. (DoD adopted) F 593 - Standard Specification for Stainless Steel Bolts, Hex Cap F 594 - Standard Specification for Stainless Steel Nuts. A 269 - Standard Specification for Seamless and
27、Welded Austenitic Screws, and Studs. (DoD adopted) (DoD adopted) (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS (ASHEUE) Standard 25 -
28、Methods of Testing Forced Convection and Natural Convection Air Coolers for Refrigeration. (Application for copies should be addressed to the American Society of Heating, Refrigerating and Air-conditioning Engineers, 1791 Tullie Circle NE, Atlanta, GA 30329.) Provided by IHSNot for ResaleNo reproduc
29、tion or networking permitted without license from IHS-,-,-MIL-C-24746 41 = 9999906 0469815 5 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) ANSI/ASME B31.5 - Refrigeration Piping. (Application for copies should be addressed to the American Society of Mechanical Engineers, United Engineering Center,
30、 345 East 47th Street, New York, NY 10017.) UNDERWRITERS LABORATORIES INC. (UL) 412 - Refrigeration Unit Coolers. (Application for copies should be addressed to the Underwriters Laboratories Inc., 333 Pfingston Road, Northbrook, IL 60062.) (Non-Government standards and other publications are normall
31、y available from These documents also the organizations that prepare or distribute the documents. may be available in or through libraries or other informational services.) 2.3 Order of Drecedence. In the event of a conflict between the text of this document and the references cited herein, the text
32、 of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 First article. When specified (see 6.2), a sample shall be subjected to first article inspection (see 6.5) in accordanc
33、e with 4.4. 3.2 Reliability. The equipment shall have an operating life of at least 40,000 hours. have a mean-time-between-failures (MTBF) of 8;OOO hours, mean-time-to-repair (MTTR) of 8 hours, mean-time-between-correcrive-maintenance (MTBCM) of 8,000 hours, and an operational availability (A,) of 0
34、.95 (see 4.6.14.6). The forced air unit coolers supplied by this specification shall 3.3 Materials, Materials for use in the construction of the unit coolers shall be as specified in table I, or as otherwise specified (see 6.2). TABLE I. Materials and Drocesses. Application Unit coo 1 er Casing, fra
35、me mounting brackets, and fasteners (nuts and bolts) Louver Drain pan Materials 302 or 304 stainless steel 302 or 304 302 or 304 stainless steel stainless steel Specification ASTM A 240, A 269, A 276 F 593, F 594 as applicable ASTM A 240, A 269, A 276 ASTM A 240, A 269, A 276 F 593, F 594 as applica
36、ble F 593, F 594 as applicable 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE I. Materials and processes - Continued. App 1 icat ion Identification plate Welding electrodes and rods Insulation Insulation adhesive Cooling coil Tubes Suction h
37、eader Fins Tube sheets Ferrules Brazing Refrigerant Fan assemblv Fan blade and hub Fan guard Electrical enclosures Controls enclosure Junction box attached Gaskets remote to unit cooler to unit cooler Materials 302 or 304 stainless steel Low carbon steel Seamless copper tube Seamless copper tube 300
38、0 or 5000 series 302 or 304 stainless Copper or brass Silver brazing alloy Type R-12 or R-22 aluminum alloy steel or phosphorous copper Bronze, aluminum alloy or corrosion resis- tant steel stainless steel 302 or 304 ASTM A 366 and 304 stainless steel ASTM A 789 Silicon rubber Specification ASTM A 2
39、40, A 269, A 276 F 593, F 594 as applicable MIL-E-19933, MIL-E-22200/2 MIL-P-15280 MIL-P-15280 ASTM B 68 ASTM B 68 ASTM B 209 ASTM A 240 ASTM B 111 QQ-B- 654 BB - F- 1421 ASTM B 108 ASTM A 240, A 269, A 276 F 593, F 594 MIL-E-24142 MIL- E- 24142 MIL-R-46089 3.3.1 Materials not specified. When a defi
40、nite material is not specified, a material shall be used which will enable the unit cooler to meet the performance requirements of this specification. Acceptance or approval of any constituent material shall not be construed as a guarantee of the acceptance of the finished product. Materials shall b
41、e free from defects and suitable for the purpose intended. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-24746 41 M 9999906 0469817 9 M 3.3.2 Dissimilar metals. Direct contact of electrolytically dissimilar metals, as defined and classified
42、 in accordance with MIL-STD-889, shall be prohibited. 3.3.3 Recovered materials. Unless otherwise specified herein, all equipment, material, and articles incorporated in the products covered by this specification shall be new and may be fabricated using materials produced from recovered materials to
43、 the maximum extent practicable without jeopardizing the intended use. The term “recovered materials“ means materials which have been collected or recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. interpreted to mean that the use of u
44、sed or rebuilt products is allowed under this specification unless otherwise specifically specified. None of the above shall be 3.4 Size and caDacity. described in 1.2 or as specified (see 6.2). following design conditions. Sizes and capacities of unit coolers shall be as The capacities shall be bas
45、ed on the 3.4.1 Air-on temuerature. Unit coolers shall meet the rated capacity with an air-on (inlet air) temperature of minus 10 degrees Fahrenheit (“F) and an evaporator (refrigerant) temperature of minus 20F. 3.4.2 Liauid refrigerant temuerature. For coil and expansion valve sizing, the liquid re
46、frigerant temperature at the inlet of the expansion valve shall be taken as 103F with a corresponding pressure of 123 pounds per square inch ( lb/in2) gauge. 3.4.3 Air velocity. Air velocity across the face of the coil shall be not greater than 600 feet per minute (ft/min). 3.4.4 Convertibility. Uni
47、t coolers shall be convertible from frozen storage application to chilled storage. Design storage temperatures for frozen storage and chilled storage shall be minus 10F and plus 33F respectively. 3.5 Construction. Forced air unit coolers shall consist of a casing, evaporative cooling coil, fan and m
48、otor assemblies, and louvers located on the coil side of the unit cooler which close during the defrost cycle, built as a single unit, ready for installation and connection to the refrigerant supply and return lines, and condensate drain line (see 6.3). Each unit cooler shall have electric defrost w
49、hich shall consist of electric heating elements in direct contact with the finned surface, drain pan, and drain line. The cooling and defrost controls shall be combined in a single enclosure, separate from the unit cooler, and ready for connection to the power supply and the unit cooler. 3.6 Shock. Unit coolers and controls shall withstand the high impact shock requirements in accordance with MIL-S-901 for grade A, class I equipment. 3.7 Vibration. Unit coole
