Abstract: An electrolytic solution control method can control the composition of an electrolytic solution efficiently with high precision, and can remove a partially decomposed product of an organic component from an electrolytic solution. The electrolytic solution control method includes storing an electrolytic solution containing an organic component and an inorganic component in an electrolytic solution storage tank while controlling and keeping the electrolytic solution at a predetermined composition, adjusting an inorganic component of the waste electrolytic solution after use in electrolytic processing in an electrolytic processing apparatus, and then returning the waste electrolytic solution to the electrolytic solution storage tank.

Abstract: There is provided an electrolytic solution supply and recovery facility which, in response to an increase in the production amount of an associated electrolytic processing apparatus, can efficiently supply and recover an electrolytic solution while enhancing the productivity and lowering the production cost. An electrolytic solution supply and recovery facility for supplying and recovering an electrolytic solution to and from an electrolytic processing apparatus, includes: a fresh liquid supply section for storing a fresh electrolytic solution, said electrolytic solution having been transferred from a carry-in container that has been carried in from the outside, and for supplying the fresh electrolytic solution to the electrolytic processing apparatus; and a waste liquid recovery section for recovering the electrolytic solution from the electrolytic processing apparatus, storing the electrolytic solution and transferring the electrolytic solution to a carry-out container which is to be carried to the outside.

Abstract: A pressure control valve for maintaining a control pressure constant even if the flow rate of pressurized oil varies, and an oil supply apparatus adapted for a turbo machine using this pressure control valve. The pressure control valve drives a throttle valve by a hydraulic cylinder through the operation of the piston of the cylinder by a guide valve. A port is formed so as to throttle and release the oil at the input side to control the pressure at the inlet side of the valve, oil from the output side for controlling the pressure is guided to the guide valve, and the cylinder communicates with an oil pressure source through the guide valve. An oil supply apparatus which has this pressure control valve guides a pilot tube leading from the header which feeds to the load side of the guide valve, and guides the pressurized oil from the conduit between the pressurized oil supply source to the header and to the throttle valve, thereby releasing the pressurized oil to an oil tank.