An air compressor includes a compressor main body that compresses air; a storage tank that stores the gas compressed by the compressor main body; a motor that rotates a rotary shaft to drive the compressor main body; and a control unit that controls a drive of the motor. In a case where a value of a voltage to be supplied to the motor is lower than a first voltage value, the control unit detects a stop time of the compressor and changes an operation stop pressure which is a pressure to stop the drive of the motor, based on the stop time.

The purpose of the present invention is to provide a gas compressor that can achieve reduced fluctuation of discharge pressure during compressor body number control, and a method for controlling the gas compressor. This gas compressor includes a plurality of compressor units each having a compressor body, a motor for driving the compressor body, and an inverter for controlling a rotational speed of the motor, and a control device for controlling each of the inverters, in which discharge pipes of the compressor bodies are merged with one main discharge pipe and discharge pressure of the main discharge pipe is controlled through control of pressure of the respective discharge pipes by controlling, by means of the respective inverters, driving frequencies of the compressor bodies. The control device determines whether recovery through an increase in the driving frequency of the motor of each of the compressor bodies is possible, on the basis of the pressure value and a temporal changing amount of the discharge pressure of the main discharge pipe when the driving frequency of the motor of the compressor body is being increased but has not reached an upper limit frequency, and controls an increase of the number of the compressor bodies to be operated.

A built-in air pump comprises a housing body and a panel. The panel couples to the housing body and defines an opening. A main pump body couples to the housing body and defines a first accommodating chamber in fluid communication with the opening and with a first and a second venting port. An air replenishing pump has an air replenishing pump body that is located adjacent to the main pump body. The air replenishing pump body couples to the housing body and defines a second accommodating chamber having therein the air replenishing pump. An air passage switch, located in the first accommodating chamber, is moveable between a first and a second position. A controller is in electrical connection with the air replenishing pump and configured to activate the air replenishing pump based on a time determination. An inflatable body including the built-in air pump assembly is also disclosed herein.

A compressed air system for a motor vehicle with an air supply system includes an electric drive motor, which can be controlled for variable speed, an air compressor coupled to be driven by the electric drive motor, an electric power supply for supplying electric power to the electric drive motor, at least one air reservoir connected with the air compressor to receive air from the air compressor, an air utilization system connected to the air reservoir to receive air from the air reservoir, and a controller to control the speed of the electric drive motor. The controller controls the electric drive motor to determine its speed depending upon at least one of the following signals: a signal representing the activation status of an accelerator pedal of the vehicle, a signal representing the speed of the vehicle, a signal representing the temperature of the power supply, a signal representing the temperature of the electric drive motor, a signal representing the wetness level of the air compressed by the air compressor, a signal representing the load of the air compressor, a signal representing the running time of the air compressor, or a signal representing the status of the electric power supply.

An agricultural work vehicle having an air supply device includes: an air compressor for pressurizing air; an air tank for storing the air compressed by means of the air compressor; a pressure sensor for measuring the pressure of the air stored in the air tank or atmospheric pressure; a controller for stopping the operation of the air compressor when the measured pressure exceeds a first reference value; and an air pressure regulator for discharging, to the outside, the air inside an air pressure circuit system so as to reduce the pressure when the pressure of the air stored in the air tank exceeds a second reference value.

A compressed air production facility that reduces an extension cost without stopping an operating air compressor in a case of increasing the number of air compressors to cope with an increase in demands for compressed air is provided. A compressed air system supplies compressed air to compressed air consuming devices connected to a compressed air distributions line, the compressed air system including a plurality of air compressor units connected to the compressed air distributions line via respective air tanks. Each of the air compressor units includes: an air compressor main body; an adjustor of pressure setpoint that adjusts a pressure setpoint of an air tank to which the air compressor unit including the adjustor of pressure setpoint is connected; and a controller of air compressor that operates a rotational frequency of the air compressor main body on the basis of the pressure setpoint adjusted by the adjustor of pressure setpoint and a pressure of the air tank. The adjustor of pressure setpoint adjusts the pressure setpoint on the basis of a control variable indicating the rotational frequency of the air compressor main body or the pressure of the air tank.

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 hydraulic system comprises a fluid tank and a pump, including a pump reservoir, fluidly coupled to the tank via a supply line. A valve is in fluidic communication with the pump reservoir via a pressure line. A backflow line fluidly couples the pump reservoir to the fluid tank via a timer reservoir and an orifice included in the timer reservoir. The hydraulic system transitions between a normal state and a purge state. In the normal state in which the pump is on, a first portion of the fluid is communicated from the pump reservoir to the valve and a second portion of the fluid is communicated from the pump reservoir to the tank. In the purge state, the pressure line and valve are purged followed by the backflow line and the pump reservoir such that no fluid remains in the pump reservoir.

The invention relates to a method of fluid exchange using a separation apparatus, in controlled fluid communication with an inlet and an outlet. Opening of the inlet enables fluid communication with the separation apparatus, exchange of fluid (a first fluid exchange) of a first volume of fluid, sealing/closing preventing further fluid communication. Opening of the outlet to be in fluid communication with the separation apparatus enables exchange of fluid (a second fluid exchange) through the open outlet of a second volume of fluid. In the method, the outgoing volume of fluid and the incoming volume of fluid in each exchange are substantially similar and there is substantially no loss of pressure by virtue of the exchange. The invention also relates to a separation apparatus, including a separation chamber and a control system.

A hydraulic system comprises a fluid tank and a pump, including a pump reservoir, fluidly coupled to the tank via a supply line. A valve is in fluidic communication with the pump reservoir via a pressure line. A backflow line fluidly couples the pump reservoir to the fluid tank via a timer reservoir and an orifice included in the timer reservoir. The hydraulic system transitions between a normal state and a purge state. In the normal state in which the pump is on, a first portion of the fluid is communicated from the pump reservoir to the valve and a second portion of the fluid is communicated from the pump reservoir to the tank. In the purge state, the pressure line and valve are purged followed by the backflow line and the pump reservoir such that no fluid remains in the pump reservoir.