Abstract:
A piston stroke limiting device for a reciprocating compressor of the type including a piston (2) reciprocating inside a cylinder (3), which is closed by a cylinder head (4) and defines, between the latter and the top of the piston (2), a compression chamber (5), said device comprising: a driving element (40) provided in one of the parts defined by the piston (2) and the cylinder head (4) and projecting to the inside of the compression chamber (5), in order to touch the other of said parts when the piston (2) surpasses a predetermined nominal position at the end of the compression stroke; and a relief valve (60), which is selectively displaced from a closed condition, in which it is seated on a respective valve seat (51) defined in a relief passage (50) communicating the compression chamber (5) with a region of the compressor subject to a substantially lower operational pressure, to an open condition, by action of the driving element (40), when the piston (2) surpasses said predetermined nominal position at the end of the compression stroke.
Abstract:
An apparatus and a method for controlling operation of a linear motor compressor, by which a linear motor compressor can operate always in an optimum condition by coping with the load variation due to changes in a refrigerator and the circumstances. In more detail, a current peak value at TDC=0 is detected by comparing a current applied to the linear motor compressor with a formerly detected current, and accordingly the linear motor compressor is operated by a switching control signal generated according to a duty-ratio corresponding to the current peak value.
Abstract:
A two stage reciprocating compressor and associated HVAC systems and methods are disclosed. The reciprocating compressor includes a crankshaft having an eccentric crankpin, a reversible motor for rotating the crankshaft in a forward and a reverse direction, and an eccentric, two position cam rotatably mounted over the crankpin. The crankshaft and cam combine to cause the piston to have a first stroke when the motor operates in the forward direction and a second stroke when the motor operates in the reverse direction. The cam and crankpin also include stabilization means to restrict the relative rotation of the cam about the crankpin. A lubrication system is provided to lubricate the engaging surfaces of the crankshaft and cam and between the cam and the bearing surface of the connecting rod. There is also provided a control for selectively operating the motor either in the forward direction at a first power load or in the reverse direction at a reduced second power load. A protector for the motor is also provided. In addition, the application of the reciprocating compressor to both air conditioning and heat pump systems is disclosed.
Abstract:
A gas compression apparatus for reciprocating compressor includes: a reciprocating motor generating a linear reciprocal driving force; a compressing cylinder positioned with a predetermined distance from the reciprocating motor; a position controlling cylinder positioned with a predetermined distance from the compressing cylinder; an initial position variable type piston inserted into the compressing cylinder and the position controlling cylinder, and being linearly and reciprocally moved within the compressing cylinder and the position controlling cylinder; and a pressure controlling valve controlling a pressure inside the position controlling cylinder with the pressure of the gas discharged from the discharge chamber. Therefore, the gas compression amount can be controlled by controlling the stroke distance of the initial position variable type piston according to the voltage control of the motor, and at the same time, by controlling the reference position of the initial position variable type piston for the stroke distance of the initial position variable type piston; since the top-clearance of the initial position variable type piston is constantly maintained, the refrigerant gas can be compressed as much as required, an efficiency of the system can be heightened by preventing a refrigerant gas compression loss; and since the dead volume is minimized, an efficiency of the compressor can be improved by preventing a re-expansion loss.
Abstract:
In an apparatus and a method for controlling operation of a linear compressor, operation of a linear compressor is controlled by finding each inflection point as a TDC (top dead center) is 0 by using a current and a displacement vector generated in the linear compressor, determining a duty ratio on the basis of the inflection point and generating a switching control signal according to the determined duty ratio.
Abstract:
An apparatus for controlling an operation of a linear compressor by which an instablel phenomenon caused due to a characteristics deviation of parts of a compressor is corrected to stabilize the operation of the system, thereby accomplishing an optimal operation. Also, when the tuning instability occurs due to the characteristic deviation and the assembly deviation of the mechanic unit of the compressor, and the parts deviation in the control circuit such as the sensorless stroke estimator, the compressor deviation is corrected by using a relative coordinate value. And, while the linear compressor is being operated with the stroke command value according to the cooling mode, in case that the current stroke is in an unstable state, the stroke command value is lowered down as much as a predetermined value, with which the linear compressor is operated for a predetermined time. Then, when a predetermined time lapses, it is operated with the original stroke command value, thereby evading the instablel state. In addition, the tuning instability region is searched for depending on the discharge side pressure and the suction side pressure of the compressor or the outer air temperature while the linear compressor is being operated, in order to avoid it, thereby accomplishing the optimal operation of the linear compressor.
Abstract:
A tightly closed casing has an inside space for storing coolant gas. A block is accommodated in this casing. A motor includes a stator and a mover. A piston is connected to the mover of the motor. A movable element includes the mover of the motor and the piston. A stationary element includes the stator of the motor and the block. An elastic element has a portion fixed to the movable element and another portion fixed to the stationary element. A cylinder is shiftable in an axial direction with respect the block. A shifting device shifts the cylinder in the axial direction.
Abstract:
A rodless pump is disclosed which is connected to a pressure source via a conduit. In a common oilfield application the pump would be connected to the bottom of a tubing string within the reservoir fluid to be produced. A pressure source such as a hydraulic pump would be connected at the surface to the tubing string so as to selectively apply pressure via fluid in the conduit to the pump, raising the plunger assembly in the pump drawing reservoir fluid into the pump. When pressure via the surface pressure source is released, a gas source in the pump urges the plunger assembly downward in the pump urging the reservoir fluid in the pump into the tubing and to the surface. Preferably, the pump includes dampening mechanisms at both the top and bottom of the plungers stroke so as to reduce metal to metal impact within the pump. This dampening mechanism may include but is not limited to elastomer barriers, springs, and other dampening mechanisms such as discussed further below.
Abstract:
A pump or compressor wherein the volumetric displacement of a piston cylinder assembly is variable. The piston is connected to a crank slider or eccentric mechanical drive, the crankshaft of which oscillates alternately clockwise through a controllably variable angle .theta. and counterclockwise through substantially the same angle .theta., the angle .theta. being measured from the angular position of the crankshaft or eccentric at which separation between piston and the closed end of the bore is a minimum (Top Dead Center). The angle of crank oscillation controls the degree of volumetric displacement of the piston. The crank shaft is connected to a torsional spring so as to substantially resonate the rotational inertia of the moving parts. An oscillating electric motor supplies the oscillating torque to drive the mechanism at constant frequency but controllably variable angular amplitude.
Abstract:
A control system for controlling the stroke length of an axially reciprocating shaft in a double-diaphragm pump between a leftmost shaft position and a rightmost shaft position. In one embodiment, the control system includes a marker on the shaft of the pump. A sensor is positioned adjacent to the shaft and located along the longitudinal axis of the shaft with respect to the marker to sense a change in the position of the marker when the shaft is at the leftmost and rightmost positions. The sensor sends signals to a controller that in turn sends a response signal to a driver. The drive alternates directing pressurized air to a first air cell and a second air cell to selectively reciprocate the shaft in a desired direction between the leftmost and rightmost shaft positions.