1、Comments, suggestions, or questions on this document should be addressed to: Commander, Naval Sea Systems Command, ATTN: SEA 05S, 1333 Isaac Hull Avenue, SE, Stop 5160, Washington Navy Yard DC 20376-5160 or emailed to CommandStandardsnavy.mil, with the subject line “Document Comment”. Since contact
2、information can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.dla.mil. AMSC N/A FSC 2090 INCH-POUND MIL-DTL-23919C(SH) 07 August 2012 SUPERSEDING MIL-DTL-23919B(SH) 03 June 2009 DETAIL SPECIFICATION REFERENCE CELL, IMPRESSED
3、 CURRENT CATHODIC PROTECTION (ICCP) SILVER-SILVER CHLORIDE This specification is approved for use by the Naval Sea Systems Command, Department of the Navy, and is available for use by all Departments and Agencies of the Department of Defense. 1.1 Scope. This specification covers circular silver-silv
4、er chloride flush type reference electrodes used in impressed current cathodic protection systems. The reference electrode provides the control signal to the impressed current system and may be used to monitor the system operation. It includes features of design and fabrication of these electrodes,
5、including alternate components. 1.2 Classification. Silver-silver chloride reference cells are of the following types, grades, classes, and performance levels, as specified (see 6.2): 1.2.1 Type. a. Type I Standard Cell b. Type II Diver Replaceable Cell 1.2.2 Grade. a. Grade A Mesh Reference Cell b.
6、 Grade B Plate Reference Cell 1.2.3 Class. a. Class I Surface Ship b. Class II Submarine 1.2.4 Performance levels. a. Performance A Standard Performance b. Performance B High Performance Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-23919C(
7、SH) 2 1.3 Part or identifying number (PIN). PINs to be used for silver-silver chloride reference cells acquired to this specification are created as follows: M 23919 - X X X X Prefix for Military Specification Specification Number Type (see code below) Grade (see code below) Class (see code below) P
8、erformance (see code below) Type code Grade code Class code Performance code I 1 A A I 1 A A II 2 B B II 2 B B Example: M23919-1A1A Standard Cell, Mesh Reference Cell, Surface Ship, Standard Performance 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sectio
9、ns 3, 4, or 5 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must m
10、eet all specified requirements of documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent
11、specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-S-901 - Shock Tests, H.I. (High-Impact) Shipboard Machinery, Equipment, and Systems, Requirements for MIL-C-24231 - Connectors, Plugs,
12、 Receptacles, Adapters, Hull Inserts, and Hull Insert Plugs, Pressure-Proof, General Specification for (Copies of these documents are available online at https:/assist.dla.mil/quicksearch/ or https:/assist.dla.mil.) 2.3 Non-Government publications. The following documents form a part of this documen
13、t to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. ASTM INTERNATIONAL ASTM E11 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves (Copies of this document are available from ASTM Internati
14、onal, 100 Barr Harbor Dr., P.O. Box C700, West Conshohocken, PA 19428-2959 or online at www.astm.org.) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-23919C(SH) 3 SAE INTERNATIONAL SAE-AMS-P-83461 - Packing, Preformed, Petroleum Hydraulic Fl
15、uid Resistant, Improved Performance at 275 Mdf (135 Mdc) SAE-AS8660 - Silicone Compound NATO Code Number S-736 (Copies of these documents are available from SAE World Headquarters, 400 Commonwealth Drive, Warrendale, PA 15096-0001 or online at www.sae.org.) 2.4 Order of precedence. Unless otherwise
16、noted herein or in the contract, in the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. R
17、EQUIREMENTS 3.1 First article. When specified (see 6.2), a sample shall be subject to first article inspection in accordance with 4.2. 3.2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent p
18、ossible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous life-cycle costs. 3.3 Construction. 3.3.1 Silver-silver chloride electrode element. 3.3.1.1 Chemical purity. The silver (Ag) wire used in fabricating the mesh/pla
19、te shall not contain less than 99.95 percent silver metal base purity. The silver chloride (AgCl) coating shall also have a metal basis purity of no less than 99.95 percent (see 4.5.7). 3.3.1.2 Cleaning. The silver surface shall be degreased and surface oxide fully reduced (cleaned) by means of a hy
20、drogen flame or equivalent chemical method just prior to application of AgCl. The silver surface shall be bright and shiny once it has been cleaned. The silver shall be handled with stainless steel tongs to prevent contamination. 3.3.1.3 Application of AgCl coating. The AgCl coating shall be applied
21、 by either an electroplating or hot dipping process. Sintering shall not be used unless prior approval of the process has been granted by NAVSEA. 3.3.1.4 Surface area. In order to achieve adequate surface area, the Grade A silver element shall have a mesh size of 40 or finer. For a Grade B element,
22、the final surface area of the plate shall be not less than 0.546 inches squared (3.52 centimeters squared) or as approved by NAVSEA (see 4.5.8). 3.3.1.5 Life. The service life of a reference cell shall be 12 years without degradation at input impedance of the reference cell monitoring circuit (see 4
23、.5.9). 3.3.2 Electrical connection. The pin shall be made out of a noble material and plated in 99.95 percent silver metal base purity and shall have a measured resistance of less than 1.0 ohms. Type II reference cells shall be constructed such that the connection to the pin remains dry and free fro
24、m oxidation after underwater replacement (see 4.5.10). 3.3.3 Assembly. 3.3.3.1 Material. The reference cell assembly shall be made of a non-conductive material to ensure that there is isolation (no shorting or grounding) between the reference cell and the hull, preferably poly-vinyl chloride. 3.3.3.
25、2 Pressure. The reference cell assembly shall be able to withstand the design pressure depending on the class/hull of the specific vessel. After testing both Class I and Class II reference cell assemblies, testing in accordance with 4.5.2 shall be repeated. Reference cells shall show no evidence of
26、mechanical damage, water leakage, or impaired electrical characteristics (see 4.5.6). 3.3.3.3 Shock. The reference cell assembly shall be certified as shock Grade B (see 4.5.11). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-23919C(SH) 4 3.
27、3.4 O-rings. O-rings for the hub of the base assembly shall be circular rubber rings conforming to SAE-AMS-P-83461. Sealing grease for installation of the O-rings shall conform to SAE-AS8660. 3.3.5 Fasteners. The fasteners used to attach the assembly to the structure to be protected shall be made fr
28、om corrosion-resistant material, preferably nylon. 3.4 Performance requirements. 3.4.1 Accuracy/offset. Performance A cells shall have a normalized measurement within 10 millivolts DC compared to the E244 In-Vivo Metric (IVM) standard reference cell, or equivalent standard cell. Performance B cells
29、shall have a normalized measurement within 4 millivolts DC as compared to the model E244 IVM standard reference cell, or equivalent cell. Additionally, the difference between the maximum and minimum potential values of all Performance B cells being tested shall not exceed 2 millivolts (see 4.5.2). 3
30、.4.2 Additional requirements for performance B cells. 3.4.2.1 Stability and static drift. For Performance B reference cells, the maximum change between any two reference cell elements shall not exceed 0.6 millivolt DC under constant environmental conditions over 14 days (see 4.5.3). 3.4.2.2 Temperat
31、ure linearity. For Performance B reference cells, the maximum absolute difference in slope between any two reference cell elements shall not exceed 0.035 millivolt DC/F when tested at temperatures from 40 to 90 F over 336 hours (see 4.5.4). 3.4.2.3 Water resistivity linearity. For Performance B refe
32、rence cells, the maximum absolute difference in slope when plotted on a semi-log graph between any two reference cell elements shall not exceed 0.03 millivolt DC/log(ohm-centimeter) when tested at water resistivities between 18 ohm-centimeters and 288 ohm-centimeters (see 4.5.5). 4. VERIFICATION 4.1
33、 Classification of inspections. The inspection requirements specified herein are classified as follows: a. First article inspection (see 4.2). b. Conformance inspection (see 4.3). 4.2 First article inspection. When a first article sample is required (see 3.1), inspection shall be performed on three
34、sample reference cells of each style of configuration. This inspection shall include all tests of 4.5. 4.3 Conformance inspection. Conformance inspection shall include the tests of 4.5.1 to 4.5.5 and 4.5.7 to 4.5.10. 4.3.1 Lot. For the purpose of sampling, a lot shall consist of those reference cell
35、s of each specified classification from the same production run offered for delivery at one time. However, this lot shall not exceed 200 prepared reference cells. 4.3.2 Sampling for examination. From each lot specified in 4.3.1, a minimum of three cells shall be tested, including one of any unique c
36、onfiguration (see table I). TABLE I. Sampling for examination. Lot size Sample size 3-25 3 26-50 5 51-90 6 91-200 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-23919C(SH) 5 4.3.3 Sampling for testing. Sampling for the purpose of testing s
37、hall be conducted as dictated by the individual test procedures of 4.5. 4.3.4 Rejection criteria. If a sample fails to pass any of the first article or conformance inspections, the lot shall be considered rejected. 4.4 Summary of requirements and tests. Table II summarizes the requirements and corre
38、sponding tests (with reference sections) for verification of satisfying each requirement. TABLE II. Summary of requirements and tests. Requirement paragraph Requirement First article Conformance Test paragraph 3.3.1 Silver-silver chloride electrode element X X 4.5.1 and 4.5.7 to 4.5.9 3.3.2 Electric
39、al connection X X 4.5.10 3.3.3 Assembly X - 4.5.6, 4.5.11 3.4 Performance requirements X X 4.5.2 to 4.5.5 NOTE: 1. Performance B reference cells shall pass performance requirements (see 3.4) for both conformance and first article testing. Performance A reference cells shall pass performance requirem
40、ents (see 3.4) for accuracy and offset testing only. 4.5 Test procedures. 4.5.1 Visual inspection. A non-destructive, visual inspection of the cable, assembly (if applicable), and reference element shall be performed. Upon completion of testing, if necessary, a destructive examination shall be perfo
41、rmed to inspect the integrity of the cell element. 4.5.1.1 Cable. The cable shall show no signs of damage or oxidation. 4.5.1.2 Assembly. The assembly shall show no signs of damage. All parts shall be accounted for and in working order, ready to install. 4.5.1.3 Reference element. The reference cell
42、 element shall have a surface void of cracks or foreign matter. 4.5.2 Accuracy/offset/stability testing. 4.5.2.1 Calibrated standard reference cell. A NAVSEA-approved standard cell that has been correctly prepared for immersion service shall be used to test product form cells, both Performance A and
43、 B. Standard cells used shall meet the following criteria: a. The sintered silver-silver chloride cell shall have a minimum surface area of 0.0254 square inches (0.164 square centimeters). For a circular cell this would be a 0.18-inch (4.5-millimeter) diameter. b. The element shall have a lead wire
44、connected that is soldered to the element and fully potted to prevent salt water intrusion into the connection. c. A reference cell standard tank with a minimum volume of 1.06 gallon (4 liters) shall be provided to accommodate the standard reference cells while conducting the product form testing. d
45、. The standard tank shall consist of a separate tank from the Performance A or Performance B cell test tank and shall contain 0.6 N (normal) sodium chloride (NaCl) solution. e. The resistivity of the solution in the standard cell tank shall be 18 ohm-centimeters 1 ohm-centimeter. Provided by IHSNot
46、for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-23919C(SH) 6 f. Resistivity shall be checked regularly during all product form testing (minimum once weekly) and distilled water shall be added, as necessary, to maintain the required resistivity. g. A minimum of
47、10 standard cells shall be placed in the standard tank for 96 hours at room temperature to stabilize. h. All air bubbles shall be removed from the cell surface after immersion. i. DC voltage measurement shall be conducted at the end of the stabilization period to determine the voltage (potential) di
48、fference between 9 of the cells using the 10thcell as the base cell to measure against. j. Three IVM, or equivalent, cells that measure within 1 millivolt DC of each other versus the base cell shall be identified to be used for further testing as standard cells. k. One of the three cells, called the
49、 base standard, shall be used to compare all product form cells. l. Other cells shall be maintained as spares in the event one of the standard cells fail. 4.5.2.2 Base standard reference cell failure. If the base standard IVM cell drifts more than 1 millivolt DC from the initial differential reading between any of the other standard IVM cells, the base standard will be replaced by one of the other two Ag/AgCl standard c
