Medium supply appartus

A medium supply apparatus provided with an inverter converting a frequency obtained from an AC power supply and with a medium drive part equipped with an electric motor driven by the inverter, so that a medium is supplied through a pipe by the medium drive part, the medium supply apparatus comprising:

• a storage part storing, in advance, information indicating a relation between a change in the amount of medium supplied by the medium drive part and a change in a frequency obtained by conversion in the inverter in accordance with a pipe resistance in a state that the electric motor is operated in a given condition;
• a frequency detection part detecting the frequency of the inverter in a case that the electric motor is operated in the given condition;
• a medium amount calculation part, on the basis of the frequency detected by the frequency detection part and the information stored in the storage part, calculating the amount of medium to be supplied by the medium drive part;
• a setup part setting up a necessary amount for the medium;
• and
• a frequency control part, on the basis of the necessary amount of medium set up by the setup part, the frequency detected by the frequency detection part, and the amount of medium calculated by said the medium amount calculation part, controlling the frequency to be obtained by conversion in the inverter.