A methane retention system is provided for reducing the amount of natural gas that is vented into the atmosphere during depressurization and maintenance of a natural gas compressor unit. Also provided are a method of depressurizing a natural gas compressor unit and a natural gas system, both of which include the methane retention system.

A methane retention system is provided for reducing the amount of natural gas that is vented into the atmosphere during depressurization and maintenance of a natural gas compressor unit. Also provided are a method of depressurizing a natural gas compressor unit and a natural gas system, both of which include the methane retention system.

Pumps for noncontact tonometry are provided. In one embodiment, a pump for noncontact tonometry includes a compression pump, a compression chamber, a first pressure sensor in communication with the compression chamber, a surge chamber, and a valve separating the compression chamber and surge chamber. The compression pump compresses a first volume of gas into the compression chamber. When the first pressure sensor detects a threshold pressure in the compression chamber, the valve opens and releases the gas into a surge chamber, where it combines with a gas residing in the surge chamber to form a puff of gas that escapes from the surge chamber through a flow-limiting nozzle. The components of the pump, which relies on passive rather than active components to create the controlled puff, can be assembled to have a profile that is portable and fit for home use.

A vapor recovery system comprises a vapor recovery unit, environmental tank, control system, vent line, environmental tank line, main vapor recovery unit inlet line, and a discharge line. The vapor recovery unit comprises a vapor recovery vessel and a vapor recovery compressor comprising a motor. The main vapor recovery unit inlet line is fluidly connected to the vapor recovery vessel. The vent line comprises a valve adapted to regulate packing case vapor flow through the vent line to the main vapor recovery unit inlet line. The environmental tank line is fluidly connected to the main vapor recovery unit inlet line. The control system is adapted to monitor a vapor recovery vessel input pressure and control the vapor recovery compressor. The control system is further adapted to control a vapor recovery vessel output to the discharge line.

A vapor recovery system comprises a vapor recovery unit, environmental tank, control system, vent line, environmental tank line, main vapor recovery unit inlet line, and a discharge line. The vapor recovery unit comprises a vapor recovery vessel and a vapor recovery compressor comprising a motor. The main vapor recovery unit inlet line is fluidly connected to the vapor recovery vessel. The vent line comprises a valve adapted to regulate packing case vapor flow through the vent line to the main vapor recovery unit inlet line. The environmental tank line is fluidly connected to the main vapor recovery unit inlet line. The control system is adapted to monitor a vapor recovery vessel input pressure and control the vapor recovery compressor. The control system is further adapted to control a vapor recovery vessel output to the discharge line.

An air compressor apparatus is disclosed that includes an air tank. A first compressor assembly can be fluidly coupled to the air tank, the first compressor assembly including a first head unloader valve. A second compressor assembly can be fluidly coupled to the air tank, the second compressor assembly including a second head unloader valve. A control unit can be electrically coupled to the first and second compressor assemblies, the control unit operable to control the operation of the first and second compressor assemblies. During startup, the first and second air compressor assemblies can be configured to draw less than 20 amps of current combined from a single 120 volt power source. The first and second compressor assemblies can each be dual piston compressor assemblies.

An air compressor apparatus is disclosed that includes an air tank. A first compressor assembly can be fluidly coupled to the air tank, the first compressor assembly including a first head unloader valve. A second compressor assembly can be fluidly coupled to the air tank, the second compressor assembly including a second head unloader valve. A control unit can be electrically coupled to the first and second compressor assemblies, the control unit operable to control the operation of the first and second compressor assemblies. During startup, the first and second air compressor assemblies can be configured to draw less than 20 amps of current combined from a single 120 volt power source. The first and second compressor assemblies can each be dual piston compressor assemblies.

A diaphragm compressor includes first structure having a first pressing part, a first diaphragm, and a first substrate partially separated from the first diaphragm and partially joined to the first diaphragm, a second structure having a second pressing part, a second diaphragm, and a second substrate partially separated from the second diaphragm and partially joined to the second diaphragm, the first structure and the second structure being stacked in a stacking direction in which the first diaphragm and the first substrate are stacked, wherein the first pressing part is placed at sides of the first diaphragm opposite to the first substrate, and a first separation portion between the first diaphragm and the first substrate is part of a first channel in which a fluid flows, the second pressing part is placed at sides of the second diaphragm opposite to the second substrate, and a second separation portion between the second diaphragm and the second substrate is part of a second channel in which a fluid flows, the first channel and the second channel are placed in series, as seen from the stacking direction, the first pressing part overlaps the second pressing part, and a buffer chamber holding the fluid is provided between the first channel and the second channel.

A diaphragm compressor includes first structure having a first pressing part, a first diaphragm, and a first substrate partially separated from the first diaphragm and partially joined to the first diaphragm, a second structure having a second pressing part, a second diaphragm, and a second substrate partially separated from the second diaphragm and partially joined to the second diaphragm, the first structure and the second structure being stacked in a stacking direction in which the first diaphragm and the first substrate are stacked, wherein the first pressing part is placed at sides of the first diaphragm opposite to the first substrate, and a first separation portion between the first diaphragm and the first substrate is part of a first channel in which a fluid flows, the second pressing part is placed at sides of the second diaphragm opposite to the second substrate, and a second separation portion between the second diaphragm and the second substrate is part of a second channel in which a fluid flows, the first channel and the second channel are placed in series, as seen from the stacking direction, the first pressing part overlaps the second pressing part, and a buffer chamber holding the fluid is provided between the first channel and the second channel.

A reciprocating piston air compressor includes a programmable logic controller, a tank, a motor, a pump, a variable speed drive, a head unloader and a cooling system. The programmable logic controller and/or variable speed drive are utilized to monitor the operating state of the air compressor and to control various operational variables, such as motor and pump speed. The air compressor can utilize the variable speed drive to operate a three phase motor on single-phase power.