It shall not be lawful for the said Inspector to make charges for inspecting and examining weights, measures, scale beams, patent balances, steelyards, or other instruments used for weighing, more than once in each year (except charges for inspecting and examining track scales and scales of a capacity of three [3] tons and upwards, and automatic or mechanical pumps or liquid measuring devices, which shall not be made more than one in every six [6] months), unless such weights, measures, scale beams, patent balances, steelyards, or other instruments used in weighing and measuring shall be found to be not conformable to the said standard.