A combination unit including pre-set flow regulators and pressurization pumps combines drinks in pre-determined ratios. The internal voltage generator produces an internal voltage at a high voltage level, as an internal voltage, in not only a standby section but also in an active section in response to a test operation signal activated in a test operation. 05 or less so as to excite a shear horizontal wave. The network is supplied water by a plurality of water supply lines which originate at a manifold.