A torque estimating device of a gas compressor includes a reference torque characteristic storage unit that stores a reference torque characteristic of the gas compressor as a torque characteristic of the gas compressor in a specific operation state, a torque setting unit that sets a torque corresponding to an input speed of rotation of the gas compressor and pressure of a refrigerant discharged from the gas compressor, on the basis of the reference torque characteristic stored in the reference torque characteristic storage unit, and a torque correcting unit that sets a torque at startup of the gas compressor among the torques set by the torque setting unit, by correcting the torque set by the torque setting unit, in accordance with the speed of rotation and an elapsed time from startup.

A reciprocating electric motor includes a housing, a stator member disposed in the housing, a reciprocating armature movable relative to the housing, and a controller. The stator member includes first and second. electromagnet units opposite to each other in a longitudinal direction of the housing. The reciprocating armature includes first and second elongated pole units each of which is moved into register with a corresponding one of the first and second electromagnet units when the corresponding one of the first and second electromagnet units is energized. The controller is configured to alternately energize the first and second electromagnet units to cause reciprocating movement of the reciprocating armature.

A reciprocating electric motor includes a housing, a stator member disposed in the housing, a reciprocating armature movable relative to the housing, and a controller. The stator member includes first and second. electromagnet units opposite to each other in a longitudinal direction of the housing. The reciprocating armature includes first and second elongated pole units each of which is moved into register with a corresponding one of the first and second electromagnet units when the corresponding one of the first and second electromagnet units is energized. The controller is configured to alternately energize the first and second electromagnet units to cause reciprocating movement of the reciprocating armature.

An improved air compressor includes a cylinder fitted with a piston body and an air storage container. The cylinder and the air storage container are detachably assembled to define an air chamber. A metal seat with a through hole is provided on top of the cylinder. A valve plug is spring-biased against the metal seat. The air storage container is provided with a pressure indicator, which includes a tube defining therein a first bore and a second bore, between which a tapered annular surface is formed. When the air pressure within the air storage container exceeds a predetermined pressure set for the air compressor, the pressure indicator allows excess air to flow into the first bore of the tube and sequentially pass through the tapered annular surface and an elongated opening to be released to the ambient environment, so that objects can be prevented from damages due to excessive inflations.

An improved air compressor includes a cylinder fitted with a piston body and an air storage container. The cylinder and the air storage container are detachably assembled to define an air chamber. A metal seat with a through hole is provided on top of the cylinder. A valve plug is spring-biased against the metal seat. The air storage container is provided with a pressure indicator, which includes a tube defining therein a first bore and a second bore, between which a tapered annular surface is formed. When the air pressure within the air storage container exceeds a predetermined pressure set for the air compressor, the pressure indicator allows excess air to flow into the first bore of the tube and sequentially pass through the tapered annular surface and an elongated opening to be released to the ambient environment, so that objects can be prevented from damages due to excessive inflations.

A switch (10, 200) is provided for installation in the air conditioning (A/C) system (12) in a vehicle (16) for intermittently operating the clutch (20) in the A/C system (12) each time the control (44) in the A/C system (12) provides power to operate the clutch (20) to prevent slugging. This turns the compressor (14) a few turns each time the clutch (20) is energized during intermittent operation to purge liquid refrigerant and lubricant from the compressor (14) to prevent slugging. The switch (10, 200) can be installed in existing vehicles by connecting the switch (10, 200) in the wiring harness (18) of the A/C system (12) to the power lead (38) from the control (44) to the clutch (20) and between the ground lead (40) from the clutch (20) and a ground. The switch (10, 200) can include a microcontroller (52) for controlling the operation of a power transistor (70) to intermittently ground the clutch to provide the intermittent operation. A battery (202) can be provided to power the microcontroller (52) for a set period of time after an initial intermittent operation. This prevents additional intermittent operation for the set period of time.

A controller for operating a prime mover of a rod pumping unit includes a processor configured to operate the prime mover over a first stroke and a second stroke. The controller is further configured to compute a first motor torque imbalance value for the first stroke and engage adjustment of a counter-balance. The controller is further configured to estimate a second motor torque imbalance value for the second stroke. The controller is further configured to disengage adjustment of the counter-balance during the second stroke upon the second motor torque imbalance value reaching a first imbalance range.

A controller for operating a prime mover of a rod pumping unit includes a processor configured to operate the prime mover over a first stroke and a second stroke. The controller is further configured to compute a first motor torque imbalance value for the first stroke and engage adjustment of a counter-balance. The controller is further configured to estimate a second motor torque imbalance value for the second stroke. The controller is further configured to disengage adjustment of the counter-balance during the second stroke upon the second motor torque imbalance value reaching a first imbalance range.

A device for pumping blood, includes a housing having a distal end adapted to be coupled to a catheter, a proximal end having an outlet, and a tubular body extending between the distal and proximal ends along an axis. A rotor is rotatably disposed within the housing. A first magnetic bearing is operative to levitate the rotor along the axis within the housing. A second magnetic bearing controls a rotational frequency of the rotor. A third magnetic bearing controls a radial position of the rotor.

A system for compressing gas from a wellbore that uses a single reciprocating compressor unit to boost pressure of the gas to an intermediate stage, and from the intermediate stage to a final stage. The final stage is at a destination pressure for distribution. Between the intermediate and final stages the gas is treated to remove water and higher molecular weight hydrocarbons so that the gas pressurized to the final stage is compressed natural gas. The reciprocating compressor is made up of a series of throw assemblies that are all driven by a single shaft. Each throw assembly includes a cylinder with a piston that reciprocates within the cylinder to compress and pressurize the fluid therein. The reciprocating compressor can be a non-lube design thereby eliminating lube oil contamination of downstream compressed natural gas or higher molecular weight hydrocarbons.