Abstract: To completely prevent air from leaking out from a conduit tube, which protects an electrical wire connecting an electrical equipment and a power source, and to easily and reliably electrically connect the electrical equipment and the power source in an air shelter. A pump and a motor are covered with a cover body, and an electrical wire that connects an explosion proof connector and a power source is not protected with a flexible conduit tube in the inside of the cover body, and protected with the flexible conduit tube only on the outer side of a conduit tube connector arranged on a side wall of a base.

Abstract: To completely prevent air from leaking out from a conduit tube, which protects an electrical wire connecting an electrical equipment and a power source, and to easily and reliably electrically connect the electrical equipment and the power source in an air shelter. A pump and a motor are covered with a cover body, and an electrical wire that connects an explosion proof connector and a power source is not protected with a flexible conduit tube in the inside of the cover body, and protected with the flexible conduit tube only on the outer side of a conduit tube connector arranged on a side wall of a base.

Abstract: Provided is a device submersion preventing structure which is capable of releasing heat generated from a device such as a pump and oil vapor, and preventing submersion of the device. The device submersion preventing structure comprises an enclosure having an internal chamber 60 for installing a pump 20 therein, wherein the enclosure 60 is configured such that an opening 61 is provided only in a bottom portion thereof, and a remaining portion thereof is formed as an air-confining structure.

Abstract: An overfill preventing device in an underground liquid storage tank is characterized in that a window for extending outwardly or accommodating a float is provided on a peripheral wall of a cylindrical sleeve, that an upper end of the float is pivotally attached to the cylindrical sleeve at a position above the window, and that a closure valve is mounted on the upper end of the float to open or close the cylindrical sleeve at a position above the window. Since the window for extending the float outwardly or accommodating the float inwardly is formed inside the cylindrical sleeve, the float can be firmly stored. When the float is extended outwardly from the cylindrical sleeve after installing the device of the present invention, the window is closed by a lid and the lid forms a part of the cylindrical sleeve so that construction of the space within the cylindrical sleeve necessary for liquid flow is minimized, whereby liquid is smoothly supplied into the underground liquid storage tank.