【国外标准】 Standard Specification for Liquid Level Indicating Equipment, Electrical

This specification covers the requirements for electrical liquid level indicating equipment for shipboard low pressure and high pressure tanks containing freshwater, feed water, potable water, seawater, wastewater, diesel fuel, lubricating oil, contaminated oil, refrigerants, JP fuels, and various other fluids. Application includes compensating tanks in which the equipment must locate the interface. Each liquid level indicating equipment shall consists of one or more sensing devices; primary indicator panel assembly; and flexible interconnections, auxiliary indicator panel assembly, and portable indicator panel assembly, when needed or required. The level sensing techniques include: admittance and impedance, magnetic float, differential pressure, time domain reflectometry, capacitance, resistance tape, static pressure, radar, and ultrasonic sensing. The most common types of process media and the specified pressure range and display for liquid level indication are given. Materials for the sensing devices and wetted pans shall be selected for long-term compatibility with the process medium. Physical property requirements include: (1) enclosure, (2) liquid level indicating equipment mounting, (3) external configuration, (4) electrical connection, and (5) size and weight. Critical service life and performance requirements shall be specified in the acquisition requirements. The following performance characteristics and environmental exposures may or may not be important to the intended application: accuracy, response time, repeatability, hysteresis, insulation resistance, specific gravity, fluid conductivity, tank wall proximity, inclination, spike voltage, salt spray, vibration, shock enclosure, dc magnetic field, electromagnetic interference, immersion, and supply line voltage and frequency variation. Inspection requirements specified are classified as (1) first article test and (2) conformance test.1.1 This specification covers the requirements for electrical liquid level indicating equipment for shipboard low pressure and high pressure tanks containing freshwater, feed water, potable water, seawater, wastewater, diesel fuel, lubricating oil, contaminated oil, refrigerants, JP fuels, and various other fluids. Application includes compensating tanks in which the equipment must locate the interface.1.2 Each liquid level indicating equipment typically consists of the following components:(a) One or more sensing devices;(b) Flexible interconnections, if needed;(c) Primary indicator panel assembly;(d) Auxiliary indicator panel assembly, when required; and(e) Portable indicator panel assembly, when required.1.3 Special requirements for naval shipboard applications are included in the Supplementary Requirements section to this specification.1.4 The values stated in SI units are to be regarded as standard. Inch-pound units are provided for information only and are not considered standard. Where information is to be specified, it shall be stated in SI units.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.