Abstract: Temperature control valve apparatus for preventing back flow from a cold water line into a hot water line includes a housing having an inlet or connection to a hot water line, an outlet for a connection to a cold water line and an interconnecting bore with a valve seat. A removable valve plug is disposed in the bore proximate the valve seat and a valve spring biases the valve plug in a spaced apart relationship with the valve seat for enabling water to flow therepast and through the housing from the hot water line to the cold water line. A thermal actuator disposed in an operative position for moving the valve plug to a seating position against the valve plug is provided to prevent water flow therepast from the cold water line to the hot water line.

Abstract: An inverter-integrated electric compressor has a control device. The control device estimates a compressor suction pressure based on the temperature of the power element of the inverter, or directly measures the compressor suction pressure by a sensor, or estimates the compressor suction pressure based on a compressor suction temperature or on a compressor housing temperature. Further, the control device calculates a motor torque based on a motor rotational speed, a motor phase current, and a motor phase voltage, estimates a compressor discharge pressure based on the compressor suction pressure and the motor torque, and estimates a compressor discharge temperature based on the compressor suction pressure and the compressor discharge pressure. The electric compressor has a discharge temperature detection device in place of a conventional thermal protector.

Abstract: A motor control device includes a control condition storage unit storing at least one of a control condition defined by an equivalent voltage supplied to a three-phase motor and a control condition defined by relationship between the equivalent voltage supplied to the three-phase motor and a frequency of PWM signal, a control condition extracting unit extracting the control condition from the control condition storage unit in response to a temperature of a viscous fluid supplied by a pump having the three-phase motor as a power source, and a PWM controlling unit controlling a switching element included in an inverter circuit based on a PWM signal related to the extracted control condition when the three-phase motor is started.

Abstract: An oil-injected compressor, with an oil circuit for lubrication, and an oil separating device which is used to separate the oil from the compressed air. A self-resetting temperature switch, which is used to switch off the compressor unit when the maximum temperature limit of the incoming compressed air is reached, is provided in the region of the inlet of the compressed air, which contains oil, in the oil separating device. At least one non-self-resetting additional temperature switch is provided in the internal area of the oil separating device, which immediately switches off the compressor unit following a fire or an explosion of the compressed air, which contains oil, and which is contained in the oil separating device.

Abstract: A water pump assembly for an internal combustion engine including a housing, as well as first and second rotatable shafts supported by the housing. First and second pulleys are fixed for rotation with the first and second shafts, respectively. A pumping member is fixed for rotation with the second shaft. A flexible member engages the first and second pulleys and is sized to slip relative to one of the first and second pulleys when in an unloaded state. A control mechanism selectively applies a load to the flexible member to cease the slipping and drivingly interconnect the first and second pulleys to rotate the pumping member.

Abstract: A method of operating a multistage gas compressor system including providing a plurality of compressor stages connected in series, receiving a gas flow having contaminants within a gas passage, and supplying solvent to the gas passage at or upstream of a compressor in a compressor stage of the plurality of compressor stages to entrap or dissolve the contaminants in the gas flow. The method includes resisting disabling fouling of the compressor in the compressor stage from any contaminants entrapped or dissolved in the solvent, for example, by controlling a discharge temperature of the compressor, and/or using a type of compressor that is not susceptible to being disabled by fouling in at least the first stage. The discharge temperature can be controlled by providing the compressor with a pressure ratio selected to provide a desired discharge temperature.

Abstract: A method for controlling movement of a piston in a metering device is described. The method comprises supplying a fluid by actuating the metering device's piston, wherein compression or expansion of the fluid causes corresponding temperature variations. The method further comprises superposing a corrective movement onto the piston movement, with the corrective movement at least partly compensating for at least one of thermal expansion and contraction of the fluid induced by the temperature variations. In one embodiment, the corrective movement imposed onto the piston movement comprises two components: a reduction (74) of the compression jump (73), and a subsequent increase (75) of the piston's forward displacement rate (71) during a period (76) of time (72).

Abstract: A pneumatically operated reciprocating pump comprises two opposed pumping chambers, in each one of which a respective flexible bellow slides under the control of a pneumatically operated shuttle valve capable to alternatively let a gaseous fluid in one of the two chambers for expanding the respective flexible bellow, each one of the two chambers being connected to at least one respective suction valve and to at least one respective delivery valve. Each delivery valve is provided with a compensating elastic means capable to compensate variations of rate of fluid that is pumped by the respective chamber. The pneumatically operated shuttle valve comprises a shaped spool sliding between two limit positions within a perforated cylinder, which shuttle valve is connected, for each chamber, to one or more delivery ducts and to one or more ducts for respectively letting and discharging gaseous fluid in and from the respective chamber.

Abstract: The invention in one aspect, provides an apparatus for controlling an electric oil pump that can determine the occurrence of idling even in a region in which determination based on a load of the electric oil pump becomes difficult. The apparatus for controlling an electric oil pump according to one embodiment of the invention sets a target number of revolutions for determination tNset higher than a required number of revolutions tNreq corresponding to an operation request of the electric oil pump, and executes control of an electric motor so that the number of revolutions N of the electric oil pump approaches the target number of revolutions for determination tNset. A load (phase current Ii) of the electric oil pump is detected while executing the control of the electric motor, and the occurrence of idling in the electric oil pump is determined based on a detected pump load (Inrm, IidI).

Abstract: An electroosmotic (EO) pump is provided that includes a housing having a pump cavity, a porous core medium and electrodes. The porous core medium is positioned within the pump cavity to form an exterior reservoir that extends at least partially about an exterior surface of the porous core medium. The porous core medium has an open inner chamber provided therein. The inner chamber represents an interior reservoir. The electrodes are positioned in the inner chamber and are positioned proximate the exterior surface. The electrodes induce flow of a fluid through the porous core medium between the interior and exterior reservoirs, wherein a gas is generated when the electrodes induce flow of the fluid. The housing has a fluid inlet to convey the fluid to one of the interior reservoir and the exterior reservoir. The housing has a fluid outlet to discharge the fluid from another of the interior reservoir and the exterior reservoir. The housing has a gas removal device to remove the gas from the pump cavity.

Abstract: A control circuit for controlling the rotational speed of a fan may include a memory element to store operating data corresponding to an operational profile of the fan defined by RPM (revolutions per minute) versus temperature, with the operating data comprising a respective temperature value and a respective RPM value for each respective operating point representing a change in slope of a function that corresponds to the operational profile of the fan. A processing unit may operate to receive a present temperature value, retrieve the operating data from the storage unit, and identify a pair of consecutive operating points such that the present temperature value is greater than a lower respective temperature value of the pair of consecutive operating points, and lower than a higher respective temperature value of the pair of consecutive operating points.

Abstract: A fan delay controlling apparatus includes a connector connected to a fan of an electronic device, a power supplying module connected to the connector, and a power controlling module connected to the power supplying module. The power supplying module is connected to a fan power source and a stand-by power source. The power controlling module controls the power supplying module supply power to the fan when the electronic device including the fan powers off until an ambient temperature is lower than a predetermined value.

Abstract: An electronic device includes a circuit board comprising a first metal layer and a second metal layer. The first metal layer is affixed to one side of the circuit board, and the second metal layer is affixed to the first metal layer. A channel is defined between the first metal layer and the second metal layer. A coolant container is used to accommodate coolant. A driving unit is used to drive the coolant to circuit in the channel.

Abstract: A lubricant pump is disclosed for delivering lubricant to at least one lubricating point. The pump features a lubricant container, a pump unit, a drive assigned to the pump unit, and at least one lubricant outlet and a control unit assigned to the drive. At least one heating element is also provided and can be actuated by the control unit and/or another control unit.

Abstract: A liquid injection and ratio control system is provided for blending an additive into a main flow line at a controlled ratio. The system automatically detects variances in temperature, pressure, and additive concentration and provides compensation thereto. The system also provides for automatic flow detection, calibration responsive to a level gauge, automated data collection, and wireless bi-directional communication.

Abstract: An oil-free scroll compressor prevents wraps from being broken and provides improved reliability. The oil-free scroll compressor includes an orbiting scroll member and fixed scroll members, and has compression channels into which water is injected each formed between the intake port and exhaust port provided in the fixed scroll member. The oil-free scroll compressor includes temperature sensors each of which detects temperature in the compression channel, regulating valves each of which controls ratio of the amount of the water to be injected into the respective compression channels to the total amount of the water to be injected into the compression channels, and controller which controls the opening degrees of the regulating valves such that a difference between the detected temperatures from the compression channels is small.

Abstract: Techniques herein describe a pumping system, adapted to reduce or eliminate fluid cavitation. Optionally, the pumping system is adapted for application to a passive fluid recovery system. In one example, the pumping system includes a pump and a thermal sub-cooling device. The thermal sub-cooling device may sub-cool fluid input to a pump and heat fluid output from the pump, particularly under start-up conditions. In a further example, a controller manages power supplied to both the pump and the thermal sub-cooling device, to transition from an ambient temperature start-up condition to an elevated temperature operating condition.

Abstract: A method of operating a fan control of a cooling arrangement having at least one exhaust air unit that withdraws air heated by electrical or electronic parts of a plurality of plug-in components, and having at least one cooling unit that cools air used for cooling purposes including determining a selected temperature difference for the air used for cooling the server rack relative to power consumption of the at least one exhaust air unit and the at least one cooling unit depending on the temperature difference; measuring at least one actual temperature difference between at least two temperatures of the air used for cooling purposes; and adjusting the speed of a fan for the at least one exhaust air unit depending on a deviation between the determined optimized temperature difference and the actual temperature difference measured.

Abstract: The present invention provides a method for controlling the temperature of a fuel cell system by controlling the rotational speeds of a coolant pump and a cooling fan based on the coolant outlet temperature, the amount of heat generated by a fuel cell stack, etc. In particular, the present invention controls the temperature of a fuel cell system by utilizing a controller which receives a coolant outlet temperature from a sensor in a state where a reference temperature for each stage is determined with respect to the coolant outlet temperature and a target rotational speed for each stage is determined based on the coolant outlet temperature. Then the controller performs proportional integral (PI) control with respect to each rotational speed of a coolant pump and a cooling fan at the target rotational speed for each stage determined based on the current coolant outlet temperature detected by the water temperature sensor.

Abstract: A system and method for monitoring and controlling oil return to a compressor, characterized by monitoring and controlling oil level, oil temperature, and compressor outlet pressure, so as to determine whether the oil level is lower than a predetermined level threshold, whether the temperature in the lubricating oil box is lower than a predetermined temperature threshold, and whether the compressor outlet pressure exceeds a predetermined pressure threshold, so as to control the flow of lubricating oil returned to the oil box by controlling the valve opening of the oil return valve according to a non-segmentation principle or a segmentation principle, ensure sufficient lubricating oil in the oil box, and enhance efficiency of the system.

Abstract: Heating systems including a boiler for heating a heating fluid, a plurality of heating accessories each requiring input of heat, piping connecting the boiler with the heating accessories, at least one of the heating accessories being placed in series relative to at least one other of the heating accessories, and a valve system including a variable speed pump and an associated control system for varying flow of the heating fluid from the boiler. Each heating accessory is configured such that heating fluid from the boiler delivered through the piping to each successive heating accessory provides heat to each heating accessory and the heating fluid is returned to the boiler at a sufficiently low temperature (e.g., no more than about 120° F.) so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize the efficiency of the boiler.

Abstract: A fuel pump device includes a fuel pump in which pressure-generating components in the form of a movable piston movable through a cylinder in the fuel pump together are operable to pressurize the fuel in a chamber exposed to the components to high pressure. To prevent the clearance between the pressure-generating components from increasing with increased heating of the fuel pump and to maintain a predetermined clearance between the piston and the surrounding cylinder, a temperature-regulator maintains a temperature within a predetermined temperature range in a region of the fuel pump which includes the clearance and at least portions of the pressure-generating components.

Abstract: A rotating speed adjustment circuit for a heat dissipation fan includes a first node, a second node, a reception end for receiving a first control signal, a first resistor coupled to a voltage source and the first node, a second resistor coupled to the first node and the second node, a third resistor coupled to the second node and a ground end, a capacitor coupled to the first node and the ground end, a transistor coupled to the reception end, the second node and the ground end, an oscillator for generating an oscillating signal, and a comparator for comparing a signal of the first node and the oscillating signal, so as to output a second control signal to control a rotating speed of the heat dissipation fan.

Abstract: In a method for controlling operation of a compressor, the compressor is shut off by a control device in order to prevent thermal damages when an estimated temperature value Ts calculated by said control device exceeds an upper threshold value Tmax while the compressor remains on or is allowed to be turned on when there is a need for compression and a lower threshold value Tmin is not reached. In order to be able to more accurately estimate the estimated temperature and increase the thermal availability of the compressor, the estimated temperature value Ts is indirectly and cyclically determined by means of a mathematical-physical model that characterizes the cooling and heating properties of the compressor.

Abstract: Oil supply apparatus having an electric motor, an oil pump driven by the electric motor and supplying oil to a transmission, an oil temperature sensor detecting oil temperature, and a controller setting a drive torque value and controlling the electric motor so that the electric motor outputs a drive torque according to a detection oil temperature. The controller is configured to perform rotation speed control of the electric motor so that when judging that there is a possibility that the detection oil temperature and oil temperature close to the oil pump are different at electric motor starting, the electric motor rotates at a lower rotation speed than where the electric motor rotates by the drive torque value according to the detection oil temperature before performing the electric motor control by which the electric motor outputs the drive torque according to the detection oil temperature.

Abstract: A fan control system includes a linear adjustor, an input/output controller, and a temperature sensor. A first terminal of the linear adjustor is connected to a first power supply. A second terminal of the linear adjustor is connected to a fan and grounded via a first resistor and a second resistor in series. A third terminal of the linear adjustor is connected to a node between the first resistor and the second resistor. A first terminal of the input/output controller is connected to the third terminal of the linear adjustor via a third resistor. A second terminal of the input/output controller is connected to the temperature sensor.

Abstract: A method of operating an electrical submersible pumping system that includes realtime monitoring of the wellbore fluid and adjusting pump speed so the fluid entering the pump remains subcooled. The method can include adding sensors within the wellbore and digitally storing fluid data accessible by a pump controller. The pump speed can be increased or decreased by adjusting the frequency of the electrical power delivered to the pump motor.

Abstract: A hydraulic pump system is provided that includes a pump driven by an electric motor. The electric motor includes windings that receive power from a power source. In one example, a temperature sensor is arranged in proximity to hydraulic fluid associated with the pump, such as at an input of the pump. In another example, the temperature sensor measures the ambient temperature to predict the viscosity of the pump based upon cool down rates of the system. A controller monitors a temperature at the temperature sensor and commands power to be provided to the windings to generate heat. Electric motor power consumption can be monitored to determine viscosity. The heat reduces the viscosity of the hydraulic fluid. Bleed air may be selectively provided to a casing associated with the hydraulic fluid in response to a command from the controller. The controller actuates a valve to regulate the flow of bleed air to the casing to provide supplemental heat to the heat provided by the windings.

Abstract: Apparatus and Method for Handling Fluids at Nano-Scale Rates. A linear displacement pump produces non-pulsatile liquid flow rates as low as the nl/mm range. The pump includes a servo motor, a gear reduction, a lead screw, a linear stage, a barrel, and a plunger extending into the barrel and coupled to the stage. A microfluidic interconnect device can be coupled to the barrel. One or more of these pumps can be disposed in a thermally controlled pump assembly that includes a pump housing, a thermally conductive body disposed in the housing and including first and second opposing sides, and a temperature regulating element such as a thermoelectric device disposed in thermal contact with the thermally conductive body on a side thereof opposite to the barrel or barrels of the pumps.

Abstract: A method for controlling the feed rate of a feed pump, including a drive part having a drive motor and a hydraulic part having an intake opening, a discharge opening and a feed mechanism situated in between, a setpoint feed rate being predefined and the feed pump being triggered based on the setpoint feed rate, the temperature of the fluid and a pressure difference between the intake opening and the discharge opening of the hydraulic part of the feed pump.

Abstract: A system for controlling a heating and cooling system for use on a machine includes a condenser, an evaporator assembly, an electric motor driven compressor, and a master controller operable to determine and regulate an operational speed of the compressor. The master controller includes a plurality of control algorithms each receiving respective dynamic input information and outputting a respective controller speed request based upon the respective dynamic input information.

Abstract: A vacuum pump capable of accurately detecting a rotor temperature based on a change in permeability of a magnetic material. Two targets are fixed to a nut opposed to a gap sensor. The nut is made of pure iron, and a surface of the nut opposed to the gap sensor serves as a target. The target has a Curie temperature greater than a temperature monitoring range, and each of the targets has a Curie temperature falling within the temperature monitoring range. When the targets become opposed to the gap sensor in turn according to rotation of a rotor, three types of signals are output from the gap sensor. The difference-signal generation means generates a difference signal of each the targets, on the basis of a signal of the target. The difference signal is compared with a reference signal V0 for detecting the Curie temperatures to detect a rotor temperature.

Abstract: An electrically operated hydraulic pump having a pump portion and a motor portion includes rotation controlling means controlling rotation of a rotor, first rotor position detecting means detecting rotational position of the rotor on the basis of speed electromotive force induced by exciting coils, second rotor position detecting means detecting the rotational position of the rotor on the basis of magnetic field of a magnet provided at the motor portion, and motor operating condition detecting means detecting operating condition of the motor portion. The rotation controlling means switches a first rotation controlling based on the rotational position of the rotor detected by the first rotor position detecting means, and a second rotation controlling based on the rotational position of the rotor detected by the second rotor position detecting means, on the basis of a result detected by the motor operating condition detecting means.

Abstract: A process for storing a monomer phase which is liquid under the conditions of storage and comprises methacrylic monomers to an extent of ?95% by weight and has been obtained by condensation out of a gaseous phase or by melting a crystalline phase, in a storage vessel, in which polymer of the monomer present in dissolved form in the liquid monomer phase is removed therefrom on the route from its generation into the storage vessel, and also a process for withdrawing liquid monomer phase from the storage vessel in which polymer of the monomer present in dissolved form in the monomer phase is likewise removed.

Abstract: A method controls a compressor for delivering a pressure medium into a pressure medium system, for example an air suspension system in a motor vehicle. In the method, the delivery of the pressure medium can be switched on and off as a function of a temperature signal by the compressor temperature being measured by a temperature sensor which is arranged on the compressor and the switching on and off of the compressor is controlled by an electronic control unit. The switching-on time duration and/or the switching-off time duration or the switching-off and/or the switching-on temperature are/is determined from the rise of the compressor temperature which is measured at short time intervals.

Abstract: A method of operating an auxiliary pump for an electrically variable transmission includes purging the auxiliary pump when an auxiliary pump temperature is below a minimum operating temperature and above a minimum purge temperature. The auxiliary pump fluid temperature and the minimum purge temperature are determined based upon the transmission fluid temperature and the ambient temperature.

Abstract: A condensation sensor is provided within a power supply device that is provided integratedly with a vacuum pump main unit. When the condensation sensor detects condensation within the power supply device, a CPU closes a cooling water valve. This stops the flow of cooling water that flows through the interior of the power supply device, through a cooling water duct.

Abstract: A fan has a sensor (86; 186) for sensing at least one value of the air that flows through the fan (20; 120). The fan has a fan housing (22, 24; 122, 124); an electronically commutated external-rotor motor, arranged in that housing, having an internal stator (30; 130) and an external rotor (46; 146); a fan wheel (56; 156) coupled to the external rotor (46; 146); an air inlet opening (58; 90; 158) for the inflow of air that is to be moved by the fan wheel (56; 156); a circuit board (68; 185) having a portion (66; 188) that extends adjacent the air passage opening (58; 158); and conductors (82, 84; 182?, 182?) arranged on that portion (66; 188), to which conductors the sensor (86; 186) is connected, preferably by a Surface Mounted Device (SMD) method. Premounting the sensor on the circuit board facilitates automated manufacture and reduces cost.

Abstract: The present invention discloses a cooling-fan rotation-speed control circuit, wherein a plurality of sets of input power sources respectively having different voltages is electrically and parallel coupled to a cooling fan; a switch is installed between at least one input power source and the cooling fan; the switch is turned on/off according to a rotation-speed parameter to determine whether the cooling fan is driven by a low-voltage driving power or a high-voltage driving power.

Abstract: A pump unit comprises a primary piston pump, a secondary piston pump, and a flow path adapted for fluidically connecting in series the primary piston pump and the secondary piston pump. The pump unit's duty cycle comprises a delivery-and-fill phase, in which the primary piston pump supplies a flow of liquid to the secondary piston pump, and during the delivery-and-fill phase, the flow of liquid supplied by the primary piston pump is partly used for filling up the secondary piston pump and partly used for maintaining another flow of liquid dispensed across the secondary piston pump. The flow path comprises a heat exchanger, wherein liquid supplied by the primary piston pump passes through the heat exchanger before being supplied to the secondary piston pump.

Abstract: A method, system and device for making hot water available in a water-supply system is disclosed. The water-supply system includes a source of hot water, a hot-water line and one or more tap connections for hot water connected to the hot-water line. The method includes transporting water from the source of hot water through the hot-water line during at least a portion of periods of non-withdrawal through the one or more tap connections such that a temperature profile of water in the hot water line is at least one of substantially temporally constant and varying spatially monotonically along the hot-water line.

Abstract: An overheating protection device id disclosed for electrically coupling an electrical power source to a fluid propulsion device. The fluid propulsion device includes a propelling member within a manifold for pressurizing a fluid. The propelling member is keyed with a motor. The overheating protection device comprises a housing including a back plate, a top plate, a bottom plate, a first side plate and a second side plate for defining a cavity. The back plate, the top plate, the bottom plate, the first side plate and the second side plate define an aperture. A thermostat switch is positioned within the cavity and is electrically coupled between the electrical power source and the motor. A cover engages the aperture for sealing the thermostat switch within the housing. The cover includes a bore for relieving the thermostat switch. A thermo-conductive layer has an interior surface and an exterior surface.

Abstract: A method of controlling a motor operating a pumping apparatus of a system includes determining a trip value for a parameter, floating the trip value, and monitoring the operation of the pump. Monitoring the operation of the pump includes determining a value for the parameter, comparing the value to the trip value, and determining whether the comparison indicates a condition of the pump. The method of controlling the motor also includes controlling the motor to operate the pump based on the condition of the pump.

Abstract: A control circuit for controlling the rotational speed of a fan may include a memory element to store operating data corresponding to an operational profile of the fan defined by RPM (revolutions per minute) versus temperature, with the operating data comprising a respective temperature value and a respective RPM value for each respective operating point representing a change in slope of a function that corresponds to the operational profile of the fan. A processing unit may operate to receive a present temperature value, retrieve the operating data from the storage unit, and identify a pair of consecutive operating points such that the present temperature value is greater than a lower respective temperature value of the pair of consecutive operating points, and lower than a higher respective temperature value of the pair of consecutive operating points.

Abstract: A fuel injection controlling apparatus (electronic control unit) of an internal combustion engine, which can cause first to fourth fuel injection valves of respective cylinders connected to a fuel delivery pipe to inject a fuel, which is heated after fed from a fuel pump (feed pump), is provided with a fuel pump control unit that stops a drive of the fuel pump (feed pump) until the heated fuel in the fuel delivery pipe is reduced to a predetermined amount or less.

Abstract: A solar energy system. The system includes a thermal solar system comprising a plurality of thermal modules spatially configured as an N by M array. In a specific embodiment, the plurality of thermal modules are configured to form an aperture region and a backside region. The system has an air moving device comprising a drive device coupled to a blower device. In a specific embodiment, the drive device is spatially disposed within a fluid drive region. The system has a controller operably coupled to the air moving device.

Abstract: Process for starting a pump intended to pump a liquid contained in a tank and to produce a substantially constant outlet pressure (setpoint pressure), according to which: 1/ the temperature (T1) of the liquid held in the tank is determined and compared to a setpoint temperature (T0); 2/ if the temperature (T1) is greater than the setpoint temperature (T0), the pump is actuated; 3/ if the temperature (T1) is less than or equal to the setpoint temperature (T0), the tank is heated for a time t1; then 4/ the pump is actuated for a time t2 during which the pump outlet pressure is measured; 5/ if this pressure is stable and in an acceptable margin of the setpoint pressure, the pump is kept going; and 6/ if this pressure is not stable and/or is not in the acceptable margin of the setpoint pressure, the pump is stopped and the tank is heated for a time t3, at the end of which steps 4 to 6 are repeated.

Abstract: In one aspect, the present disclosure is directed to a method for controlling operation of an electric water pump configured to circulate a cooling fluid. The method may include detecting a startup of an electric power source associated with the electric water pump. In addition, the method may include monitoring a voltage available to the electric water pump in response to the detected startup of the power source. The method may also include providing an activation signal to the electric water pump if the monitored voltage is equal to or greater than a first threshold voltage.

Abstract: The present invention relates to a fan system and a method for its operation, including a control module (1) for controlling two circuit breakers, two circuit breakers (3, 4), two electric motors (5, 6) to which their operating voltage UB is supplied via the circuit breakers (3, 4), and at least one temperature sensor (8) on a board (2) on which the circuit breakers (3, 4) are located, the control module (1) having means for evaluating a signal TNTC from the temperature sensor (8), and for setting the pulse duty factors TV1, TV2 of pulsed control voltages at the circuit breakers (3, 4), while taking into account this signal as well as a requested fan power, in such a way that no power loss PV exceeding a specified value occurs at any circuit breaker (3, 4, 7).

Abstract: A refrigerant compressor is provided that can be assembled easily and can quickly discharge lubricating oil that leaks from contact sliding parts of its mechanical seal so as to prevent the oil from turning into sludge around the stationary ring. In a refrigerant compressor in which a mechanical seal which shaft seals the inner side and the outer side of a housing is installed at a portion of the housing through which a rotating shaft penetrates, a mechanical seal comprises a stationary ring securely fastened to the inner circumferential surface of a boss portion, a rotary ring securely fastened to the outer circumferential surface of the rotating shaft to the inside of the stationary ring so as to face the stationary ring, whereby sliding contact is formed between sides of the stationary ring and the rotary ring.