Transfer proving was initially developed to provide an easier and more accurate field meter proving method. Because of the capacity capabilities of transfer provers (2000 CFH to 80,000 CFH) transfer provers are utilized in meter shops where bell prover capacity is limited and allow for shop testing of the larger capacity meters.
TRANSFER TESTING SYSTEM
In the typical transfer testing system, air or gas passes through the meter under test (field meter) and then through the “Master” meter. The vacuum method of testing is basic to all commercially available provers. Atmospheric air is drawn through the field meter and prover by the blower system. Temperature and pressure differences are measured to enable correction of the data to a common base of comparison. The rotary meter transfer proving system is not affected by specific gravity or relative humidity of the flowing gas since under normal conditions no condensation or change of moisture contact would occur as the gas passes from the field meter to the master meter. It is a volumetric test in which the test time is not a critical variable. Automatic operation minimizes chances for human error, and built-in self-check features assure reliable system performance. The ROOTS Model 5 Transfer Prover System is typical of the commercially available units and will be utilized in this discussion. Other units may differ slightly in shape, size, or performance, but the base operating principles are the same.