BS ISO 7714:2018 pdf free

BS ISO 7714:2018 pdf free.Agricultural irrigation equipment一Volumetric valves
Metering valves intended to be used as meters with a metrological purpose shall comply with the metrological characteristics described ISO 16399:2014, Clause 4.
All parts of volumetric valves of the same size, type and model intended for disassembly, maintenance and repair produced by the same manufacturer shall be interchangeable.
All parts of the volumetric valve shall be resistant to chemicals normally used in agriculture in their conventional concentrations, and shall operate smoothly for the water quality defined in 7.1.
Upon request, the manufacturer shall supply information pertaining to the operation and safety of the valve with water of purity levels not conventionally found in agriculture, such as corrosive water.
All non-metallic parts of the volumetric valves which are exposed to sunlight shall be protected against degradation from ultraviolet (UV) radiation under the normal operating conditions of the valve.
Non-metallic parts of the valve which serve as water passages shall be opaque or shall be protected in some other manner (for instance, by a closed cover) against penetration of light to the water passages.
The flow-control mechanism of the volumetric valve shall allow a means of manual override to stop the flow at any time, such as returning the setting device to zero.
In volumetric valves with threaded ends intended for direct connection to the pipeline, the thread shall comply with ISO 7-1. Alternatively, other threads may be allowed, provided that a suitable adapter in accordance with ISO 7-1 is supplied with each threaded connection.
The expanded relative uncertainty of the volume measurement test shall not exceed 1/5 of the maximum permissible accuracy error for pattern approval and 1/3 of the maximum permissible accuracy error for initial and subsequent verifications. See 7.6.2.1 and 7.6.2.2 for the maximum permissible errors for accuracy of measurement and accuracy of dosing, respectively.
Test specimens should be taken at random from a lot of 20 volumetric valves. The minimum number of test specimens to be taken for each test and the minimum number of samples which should pass the test to qualify for International Standards shall be as specified in Table 3.BS ISO 7714 pdf download.