The present invention relates to a hydraulic attachment comprising a hydraulic circuit, the attachment being a construction or demolition tool, in particular a hydraulic breaker, demolition shears, scrap shears, a pulverizer, a gripper, a crusher bucket or a compactor, which can be mechanically connected to a support device and hydraulically connected to the hydraulic system of the support device. In order to enable the hydraulic circuit to be opened quickly and safely within an attachment and, in particular, to make it possible to display the presence of a particular pressure level within a hydraulic attachment and to determine whether a dangerous residual pressure is present in the system, a hydraulic attachment is proposed that has a residual pressure display (40) which is connected to the hydraulic circuit of the attachment in a detachable or non-detachable manner.

A structure of gas regulator comprises a space for setting an intake switchover valve formed at an outer end of a high-pressure portion and interconnected with the inside of the high-pressure portion. A pushing block is outside a diaphragm, and an elastic element is set between the pushing block and a flange at the periphery of an inner end of the pushing block. A support base outside the pushing block is abutted the elastic element and comprises an extending section extended from an inner end thereof and corresponding to the outer periphery of the elastic element and a through-hole corresponding to the pushing block. A display diaphragm with a center slot is outside the support base. A cover covered the space has a transparent side display window at the periphery thereof and a transparent outer display window at an outer end thereof.

Natural gas is produced when LNG that is contained in an insulated LNG cargo tank(s) of a non-self-propelled LNG carrier (i.e., a barge) evaporates as a result of heat leakage through the walls of the insulated cargo tank(s). The natural gas is transferred from the barge to a tugboat or a towboat that is equipped with natural gas burning engines through a flexible gas transfer assembly so that the tugboat is powered by the natural gas fuel. The pressure in the cargo tank(s) on the barge is, therefore, effectively managed to prevent or substantially reduce the buildup of pressure within the LNG cargo tank(s). The LNG can then be contained within the LNG cargo tank(s) for an appropriate period of time and can be delivered at an appropriate and acceptable equilibrium pressure and temperature.