A speaker apparatus which does not need insertion of a stand into a speaker box, and which can prevent vibrations occurring in a speaker unit from transmitting to the speaker box by the speaker apparatus itself is provided. It comprises a bleeder valve having a fixed hollow valve body defining an outlet and a valve seat and a movable obturator that cooperates with the valve seat for closing the bleeder valve and releasing blast furnace off-gas through the outlet. The virtual desktops are associated with corresponding virtual machines.