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 pump cassette is disclosed. The pump cassette includes a housing having at least one fluid inlet line and at least one fluid outlet line. The cassette also includes at least one reciprocating pressure displacement membrane pump within the housing. The pressure pump pumps a fluid from the fluid inlet line to the fluid outlet line. A hollow spike is also included on the housing as well as at least one metering pump. The metering pump is fluidly connected to the hollow spike on the housing and to a metering pump fluid line. The metering pump fluid line is fluidly connected to the fluid outlet line.

A pump cassette is disclosed. The pump cassette includes a housing having at least one fluid inlet line and at least one fluid outlet line. The cassette also includes at least one reciprocating pressure displacement membrane pump within the housing. The pressure pump pumps a fluid from the fluid inlet line to the fluid outlet line. A hollow spike is also included on the housing as well as at least one metering pump. The metering pump is fluidly connected to the hollow spike on the housing and to a metering pump fluid line. The metering pump fluid line is fluidly connected to the fluid outlet line.

A method for controlling a fan in a fan start-up stage including a first time period and a second time period comprises the following steps of: during the first time period, continuously providing a first driving signal to drive the fan; and during the second time period, continuously providing a second driving signal to drive the fan; wherein, the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal. Wherein the signal value of the first driving signal non-linearly decreases, the signal value of the second driving signal is an unchanged value. Wherein, the first time period and the second time period are adjusted for a different fan but the sum of the first time period and the second time period is always the same. A fan is also disclosed.

An air compressor system includes a motor operably connected to an air compressor, a separator tank fluidly connected to the air compressor by a supply line, a compressed air line coupled to the separator tank, a service valve connected to the compressed air line and positioned downstream of the separator tank, and a controller in operable communication with the motor, wherein in response to the controller detecting the motor operating at an idle speed, the controller reduces the motor speed to a low idle speed and reduces pressure in the separator tank, the low idle speed being slower than the idle speed.

An air compressor system includes a motor operably connected to an air compressor, a separator tank fluidly connected to the air compressor by a supply line, a compressed air line coupled to the separator tank, a service valve connected to the compressed air line and positioned downstream of the separator tank, and a controller in operable communication with the motor, wherein in response to the controller detecting the motor operating at an idle speed, the controller reduces the motor speed to a low idle speed and reduces pressure in the separator tank, the low idle speed being slower than the idle speed.

An operation method of a turbine fracturing device and a turbine fracturing device are provided. The turbine fracturing device includes a turbine engine, a speed reducer, a brake mechanism, and a fracturing pump, the method includes: driving, by the turbine engine, the fracturing pump to perform a fracturing operation through the speed reducer so as to keep the fracturing pump in an operating state, the fracturing pump being configured to suck fluid of a first pressure and discharge fluid of a second pressure, the second pressure being greater than the first pressure; and in response to an idling instruction, the turbine engine entering an idling state and triggering a brake operation so as to keep the fracturing pump in a non-operating state.

An operation method of a turbine fracturing device and a turbine fracturing device are provided. The turbine fracturing device includes a turbine engine, a speed reducer, a brake mechanism, and a fracturing pump, the method includes: driving, by the turbine engine, the fracturing pump to perform a fracturing operation through the speed reducer so as to keep the fracturing pump in an operating state, the fracturing pump being configured to suck fluid of a first pressure and discharge fluid of a second pressure, the second pressure being greater than the first pressure; and in response to an idling instruction, the turbine engine entering an idling state and triggering a brake operation so as to keep the fracturing pump in a non-operating state.

A method for operating a fluid conveying device (4), in particular a pump, a fan, a compressor or a valve, by way of a control unit (14), wherein the fluid conveying device with a deactivated emergency running mode is switched on at least in the case of initial application of an operating power of the fluid conveying device, a setpoint rotational speed specification or a setpoint actuating value specification is transmitted to the fluid conveying device, and the emergency miming mode of the fluid conveying device is activated when the setpoint rotational speed specification or the setpoint actuating value specification exceeds a triggering value or the fluid conveying device is operated for longer than an activation duration with an invalid rotational speed or an invalid actuating value. Furthermore, the invention relates to a pump arrangement, a control unit, a computer program, and a machine-readable storage medium.

A method for operating a fluid conveying device (4), in particular a pump, a fan, a compressor or a valve, by way of a control unit (14), wherein the fluid conveying device with a deactivated emergency running mode is switched on at least in the case of initial application of an operating power of the fluid conveying device, a setpoint rotational speed specification or a setpoint actuating value specification is transmitted to the fluid conveying device, and the emergency miming mode of the fluid conveying device is activated when the setpoint rotational speed specification or the setpoint actuating value specification exceeds a triggering value or the fluid conveying device is operated for longer than an activation duration with an invalid rotational speed or an invalid actuating value. Furthermore, the invention relates to a pump arrangement, a control unit, a computer program, and a machine-readable storage medium.