1、1. SCOPE 16 December 1957 SUPERSEDING MIL-D-l9645(SAIpS) 5 November 1950 MILITARY SPECIFICATION DISPLAY CASES, MECHANICALLY REFRIGERATED, SELF- CONTAINED, SALAD AND DESSERT DISPENSING, NAVAL SHIPBOARD 1.1 This specification covers mechanically refrigerated display cases for storing and dispensing sa
2、lads and desserts for Naval shipboard use. 2. APPLICABLE DOCUMENTS 2.1 The following specifications and standards, of the issue in effect on date of invitation for bids, form a part of this specification: SPECIFICATIONS FEDERAL QQ-B-621 - Brass, Commercial-Yellow, ITigh-Copper-Yellow and Naval: QQ-S
3、-763 - Steel Bars, Shapes and Forgings- Corrosion Resisting. QQ-S-766 - Steel, Corrosion Resisting: Plates, Sheets and Strips. W-T-799 - Tubing, Copper, Seamless (for Use With Solder-Joint or Flared- PPP-B-601 - Boxes, Wood, Cleated-Plywood. PPP-B-621 - %xes, Wood, Nailed and Lock-Corner. Castings.
4、Tube Fittings). MILITARY MILC-132 - Crates; Open, Wood; Maximum Capacity 2,500 Pounds. MIL-S-901 - Shockproof-Equipment, Class m. (High-Impact), Shipboard Application, MIL-E-917 - Electric Power, Equipment, asic Requirements for (Naval Ship- MIL-1-942 - Insulation Batt, Thermal, Fibrous Glass. MIL-D
5、-963 - Drawings, Production (for Electrical and Mechanical Equipment for MIL-E-2036 - Enclosures for Electric and Electronic Equipment (Naval Shipboard MIL-C-2174 - Controllers, Motor Starters and Master Switches, Direct-Current - MIL-C-2212 - Controllers, Motor Starters and Master Switches-Alternat
6、ing Current MIL-R-2693 - Rubber Special Shaped Sections, Cold Storage Door Sealing Non- MIL-P-3593 - Packaging of Refrigeration and Cooling Equipment (Excluding House- MIL-C-3769 - Crates, Intermediate, Sheathed, Wood, Nailed (for Maximum Net MIL-C-3774 - Crates, Open, Wood (2,500 to 10,000 Lb. ). T
7、ests for. board Use). Naval Shipboard Use). Use). Naval Shipboard Use. Naval Shipboard Use. watertight. hold Refrigerators) Overseas aipment. Loads of 3000 Pounds). . . Licensed by Information Handling ServicesMIL-D-L7645A YL = 7799706 0212962 5 W r; MILITARY (contd. ) MIL-P-15024 - Plates, Identifi
8、cation-Information and Marking for Identification MIL-M-15071 - Manual, Technical for Mechanical and Electrical Equipment.(Less ML-R-15137 - Repair Parts for Electrical and Mechanical Equipment (Naval MIL-S-15291 - Switches,. Rotary, Snap Action, Bureau-Design. MIL-S-15395 - Silver -Base-Brazing-A l
9、loy. MIL-2-16018 - Packaging of Switchboards, Controllers and Motor Starters (Over MIL-P-16298 - Preservation, Packaging, Packing, and Marking of Electric MIL-B-16444 - Bronze, Hydraulic Ounce Meal): Castings. ML-0-16485 - Ohmmeter (Insulation-Resistance Indicating). MiL-P-17555 - Preparation for De
10、livery of Electronic Equipment, Miscellaneous MIL-M-17556 - Motor, Direct-Current, Fractional Hp (Shipboard Use). MIL-C-20158 - Copper-Phosphorus-Alloy, Brazing. General Specifications for Inspection of Material, of Electrical, Electronic and Mechanical Equipment. Electronics). Shipboard Use). 40 Po
11、unds). Machines Having Rotating Parts and Associated Repair Parts. Electrical Equipment (Except Rotating Electrical Equipment) and Associated Repair Parts. NAVY DEPARTMENT STANDARDS MILITARY ML-STD-129 - Marking for Shipment and Storage. MIL-STD-278 - Welding and Aiiied Processes for Machinery for S
12、hips of the i I United States Navy. i I (Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procurement functions should be obtained from the procuring agency or as directed by the contracting officer.) 2.2 Other publications. - The fo
13、llowing documents form a part of this specification. Unless otherwise indicated, the issue in effect on date of invitation for bids shall apply. OFFICIAL CLASSIFICATION COMMITTEE Uniform Freight Classification Rules. (Application for copies should be addressed to the Official Classification Committe
14、e, 1 Park Avenue at 33rd Street, New York 16, N. Y.) NATIONAL ELECTRICAL MANUFACTURERS ASSCXXATION No. MG1 - 1955, Part 7 - Motors for Hermetic Refrigeration Condensing Units. (Application for copies should be addressed to the National Electrical Manufacturers Association, 155 E. 44th St. New York.
15、17, N. Y.) STANDARD FOR AIR-CONDITIONING, COMMERCIAL AND DOMESTIC REFRIGERATION STANDARD FOR SAFETY, CONDENSING UNITS, REFRIGERATION (UNDERWRITERS EQUIPMENT (UNDERWRITERS, LABORATORY, INC. SUBJECT 207() LABORATORY, INC. UL303) (Application for copies should be addressed to the Underwriters Laborator
16、ies, Inc. 161 Sixth Avenue, New York 13, New York; 207 East Ohio Street, Chicago 11, illinois; or 500 Sansome Street, San Francisco 11, California.) l2 -. Licensed by Information Handling Services._ . -_ . .- y MIL-D-l9645A(S”S) / 3. REQUIREMENTS 3.1 Materials shall be similar or equal to the applic
17、able specifications listed in 2.1 and in conform- .i ance with the requirements specified herein. nickel, and copper-nickel alloys covered by referenced specifications are considered satisfactory corro- sion-resisting materials. Where corrosion-resisting steel is specified, it shall conform to class
18、 FS302 or FS304 of Specification QQ-$763 or QQ-S-766, and where exposed in final assembly shall have a number 4 or 6 finish. Corrosion-resisting steel, when fabricated by any method that tends to reduce corrosion- resisting properties, shall be normalized to restore those properties before being ass
19、embled in any unit. chemicals, electrolytic processes, plating, or suitable paints and enamels, except that cadmium shall not be used in any way where it may come into contact with food, ice, or other materials for human consump- tion. The following methods, while not restrictive, shall be considere
20、d as a satisfactory corrosion pro- tection when properly applied. 3.1.1 Corrosion protection. - Corrosion-resisting steel, copper, brass, brome, chromium, copper- 3.1.1.1 All parts o the equipment subject to corrosion shall be protected against corrosion with (a) Hot-dipped galvanized. (b) Hot phosp
21、hate process with rust-inhibiting paint. (c) Electroplated cadmium followed by dichromate, or hot-phosphate treatment or (d) Caustic dip, sandblast process, “anodized”, coated with phenolic resin baked on, water-dip lacquer. or covered with lacquer, for alum inum. 3.1.1.2 All bolts, nuts, studs, pin
22、s, screws and such other fastenings or fittings as may be used shall be of a corrosion-resisting material, or of a material treated in a manner to render it adequately resistant to corrosion. All screws exposed in final assembly shall be corrosion-resisting steel. Self tapping screws with machine sc
23、rew threads may be used in the cabinet assembly. Sheet metal screws with sheet metal threads will not be permitted. 3.1.2 Thermal insulation. - Thermal insulation other than pipe insulation shall have a thermal con- ductivity not greater than O. 30 British thermal units (B. t. u.) per hour per squar
24、e foot per inch thickness per degree Fahrenheit (F.) temperature difference when tested in accordance with the “guarded hot plate method, specified in Specification MIL-1-942. insulation shall be applied in such a manner as to preclude the possibility of settling in service. The insulation shall be
25、installed with sutficient thickness so that condensation wiil not occur on any external surface other than door mullions on units having two or more doors, or the top, when operating under the conditions of 100F. ambient temperature with relative humidity of not less than 50 percent (see 4.4.3.2). T
26、he insulation shall be provided with a vapor barrier and designed. to prevent accumulation of moisture and possible saturation of the insulation. All insulation spaces shall be fiiled so as to leave no voids. nished on the same contract or order or built to the same drawings shall be strictly interc
27、hangeable with- out the necessity of further machining or hand fittiig of any kind. com, condensing unit, controls, and accessories all enclosed within a metal cabinet with a refrigerated well top. The cabinet shall be factory-assembled, complete, self-contained, with the refrigeration equip- ment d
28、ehydrated and charged with the necessary operating quantities of refrigerant and oil. The unit shall be ready for operation after removal of shipping protection, opening of valves, and connection to electric power. 3.2.1 Valves, controls, and equipment subject to service and repair shall be readily
29、accessible for servicing through a removable kont or back panel. Where panels are provided for access to equipment, machine screws may be used for fastening. 3.1.3 interchangeability. - Similar parts, including repair parts, or corresponding apparatus fur- 3.2 General assembly. - The unit shall cons
30、ist of an insulated cabinet with a double door, cooling I 1 4J ._ . Licensed by Information Handling ServicesMIL-D- 196454 (SHIPS) 3.2.2 Adequate ventilation shall be provided for condensing unit equipment. Air for the condensing units shall be drawn from the front, back or bottom. Where ventilation
31、 is provided, the opening shaii be the louvered type. The slotted openings shall be arranged for water shed. Louvered openings for ventila- tion shall not exceed 3/8 inch clear width and shall not have sharp or ragged edges. 3.3 General design. - The equipment shall be designed for operation under s
32、hipboard conditions of vibration, roll, pitch and shock. The refrigerating equipment shall be designed, constructed and assem- bled in accordance with the standards listed in 2.2, unless otherwise specified herein or in the contract or order. 3.3.1 The unit shall be tested for structural strength an
33、d conform with the requirements specified in Specification MIL-S-901 (see 4.4. i). the vertical in each of two vertical planes at right angles to each other (see 4,4.2). 3.3.2 The equipment shall operate satisfactorily when inciined at an angle of 15 degrees each side of 3.3.3 The:unit shall be of a
34、dequate size to hold at least 4 salad trays, 20-3/4 inches by 12-3/4 inches by 4 inches deep, in the refrigerated well and at least 8 full trays in the interior. The overall length of the cabinet shall not be greater than 5 feet, 6 inches. The overall height shall be 36 inches and the depth not grea
35、ter than 26 inches exclusive of doors and removable hardware. million (p. p. m.) in the liquid phase after being dehydrated and charged with refrigerant. 3.4 Condensing unit. - The condensing unit shaii be designed for operation with dichlorodifluoro- methane (F-12) refrigerant and shall consist of
36、a compressor, condenser, receiver (if required), fan, motor, and accessories mounted on a fabricated steel frame. The capacity of the condensing unit shall be adequate for the intended application. 3.5 Compressor. - The compressor shall be of the hermetic type for alternating current (a. c.) power a
37、nd open type for direct current (d. c.) power (see 3.9). Provision shall be made for adequate lubrication of all rubbing and wearing surfaces including operation under shipboard conditions of inclination and rolling (see 4.4.2 and 4.4.4). The unit shall be capable of operating in a system which does
38、 not equalize suction and discharge pressures during shutdown. 3.5.1 The open compressor shall be of the vertical, single-acting, reciprocating type. The shaft seal shall be replaceable in its entirety without the necessity of replacing or refinishing the crankshaft. The suction and discharge shut-o
39、ff valve connections to the compressor shall be of the flanged type capable of being unbolted from the compressor. 3.6 Condenser. - The condenser shall be forced air cooled and constructed of finned tubes. The tubes shall be not greater than 5 rows deep. Fins shall be soldered, welded, or mechanical
40、ly bonded to the tubes and shall be not less than O. O10 inch thick, and spaced not more than 6 fins per inch. The condenser shall be treated for corrosion-resistance after fabrication. The fan shall be located as nearly as is practicable to the center of the condenser face. A metal fan shroud shall
41、 be provided, where necessary, for uniform air flow. 3.7 Liquid receiver. - The liquid receiver, when furnished, shall be such that it has an internal 3.3.4 The moisture content of the refrigerating system shall be not greater than 15 parts per . volume at least 25 percent greater than the liquid vo
42、lume of the complete refrigerant charge. A liquid receiver shall be furnished when an open type compressor is used and may be used in a hermetic system. The receiver shall contain a fusible plug for protection against excessive Eemperatures. The plug shall melt at a temperature not lower than 200F.
43、and not higher than 300F. 3.8 Piping. - All piping necessary for the satisfactory operation of the equipment shall be provided. All fittings and joints, where practical, shall be brazed with silver brazing alloy conforming to grade m or N of Specification MIL-S-15395 or phosphorus copper in accordan
44、ce with Specification MLL-C-20158. Flanged or flared connections may be provided on the suction and discharge shut-off valves, at expancion 4 Licensed by Information Handling Services-. . . . . . d .- . MIL-D-l9645A(SHIPS) valves or devices, and at dehydrators to permit possible replacement. Other t
45、hreaded or screwed joints shall be seal-welded or brazed. Connections shail be kept at a minimum. Piping shail be securely sup- ported to minimize strain and vibration. 3.8.1 Where silver brazing is used on corrosion-resisting steel, the brazing alloy shall conform to grade V silver solder of Specif
46、ication MIL-C-15395. 3.8.2 Refrigerant piping system. - Pi-ping shall conform to Specification WW-T-799 and with wall 3.8.2.1 All suction lines to compressor within the machinery compartment shall be insulated to pre- vent condensation. thickness not less than that required for type N. All fittings
47、shall be of wrought or forged copper. 3.8.2.2 Where an open type condensing unit is used, a disposable type dehydrator shall be provided in the refrigerant circuit. Each dehydrator shall be equipped with an auxiliary screen or other protective means at the dehydrator outlet to prevent passage of deh
48、ydratingagent in the event of rupture of the car- tridge screen outlet. The desiccant shall be silica gel or activated alumina or a type satisfactory to the bureau of agency concerned. 3.8.2.3 A heat-interchanger shall be provided in the suction line. 3.8.2.4 A fine mesh screen shall be provided ups
49、tream from the expansion device. 3.8,3 Piping system shall withstand the pressure tests specified in 4.2.1. 3.9 Electrical equipment. - Unless otherwise specified herein, the electrical equipment shall con- form to Specifications MLL-E-917, MIL-M-17556, MIL-C-2212, MIL-C-2174 and National Electrical Manufacturers Association Standard MG1-1955, part 7, as applicable. No portion of the electrical circuit shall be grounded. The frames or enclosures of all electrical components shall be grounded to the cabinet to eliminate hazard from shorts or grounds within the equipment. E
