A slim-type gas transportation device includes a slim-type gas pump and a slim-type valve structure. The slim-type valve structure includes a first thin plate, a valve frame, a valve plate and a second thin plate. The first thin plate has a hollow portion. The valve plate is disposed within an accommodation space of the valve frame. The valve plate includes a valve opening. The valve opening is not aligned with the hollow portion. The second thin plate includes a gas outlet surface, a pressure relief surface, a gas outlet groove, an outlet aperture, a pressure relief hole and a pressure relief trench. The outlet aperture is hollowed out from the gas outlet groove to the pressure relief surface and corresponding in position to the valve opening. The pressure relief hole is spaced apart from the gas outlet groove. The pressure relief trench is concavely formed from the pressure relief surface.

A slim-type gas transportation device includes a slim-type gas pump and a slim-type valve structure. The slim-type valve structure includes a first thin plate, a valve frame, a valve plate and a second thin plate. The first thin plate has a hollow portion. The valve plate is disposed within an accommodation space of the valve frame. The valve plate includes a valve opening. The valve opening is not aligned with the hollow portion. The second thin plate includes a gas outlet surface, a pressure relief surface, a gas outlet groove, an outlet aperture, a pressure relief hole and a pressure relief trench. The outlet aperture is hollowed out from the gas outlet groove to the pressure relief surface and corresponding in position to the valve opening. The pressure relief hole is spaced apart from the gas outlet groove. The pressure relief trench is concavely formed from the pressure relief surface.

A relief device in air pump includes a main body defining an interior space and a discharge hole fluidly communicating with the interior space. The discharge hole is selectively closed and opened by a valve device. The valve device is movable in the discharge hole. The discharge hole includes a first air sealing structure and the valve device includes a second air sealing structure and a third air sealing structure adapted to selectively contact with the first air sealing structure to prevent air flowing outside of the main body through the discharge hole and in addition at least one pressure releasing structure, located between the second and the third air sealing structures, adapted to cooperate with the first air sealing structure to delimit a gap therebetween for air to flow outside of the main body.

A relief device in air pump includes a main body defining an interior space and a discharge hole fluidly communicating with the interior space. The discharge hole is selectively closed and opened by a valve device. The valve device is movable in the discharge hole. The discharge hole includes a first air sealing structure and the valve device includes a second air sealing structure and a third air sealing structure adapted to selectively contact with the first air sealing structure to prevent air flowing outside of the main body through the discharge hole and in addition at least one pressure releasing structure, located between the second and the third air sealing structures, adapted to cooperate with the first air sealing structure to delimit a gap therebetween for air to flow outside of the main body.

In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

A drawdown compressor assembly for recovering natural gas from a gas line includes a first tubing configured for connection to a first pipe of the gas line at a one end of the first tubing. A compressor is attached to an opposite end of the first tubing and configured to draw natural gas from the first pipe through the first tubing and into the compressor for being compressed by the compressor. A second tubing is connected to the compressor at one end of the second tubing and configured for connection to a second pipe of the gas line at an opposite end of the second tubing. Activation of the compressor draws the natural gas from the first pipe through the first tubing and delivers compressed natural gas to the second pipe through the second tubing.

A drawdown compressor assembly for recovering natural gas from a gas line includes a first tubing configured for connection to a first pipe of the gas line at a one end of the first tubing. A compressor is attached to an opposite end of the first tubing and configured to draw natural gas from the first pipe through the first tubing and into the compressor for being compressed by the compressor. A second tubing is connected to the compressor at one end of the second tubing and configured for connection to a second pipe of the gas line at an opposite end of the second tubing. Activation of the compressor draws the natural gas from the first pipe through the first tubing and delivers compressed natural gas to the second pipe through the second tubing.