Long-stroke hydraulically-controlled natural gas compressor

The invention relates to a long-stroke hydraulically-controlled compressor in natural gas industry. The invention adopts the technical scheme as follows: a primary gas inlet valve and a secondary gas inlet valve are mounted at the upper parts of two ends of a gas cylinder, wherein a primary gas outlet valve and a secondary gas outlet valve are mounted on the lower parts of two ends of the gas cylinder; a gas inlet pipeline is connected to the primary gas inlet valve; the primary gas outlet valve, a heat exchanger, a reversing valve and the secondary gas inlet valve are connected in series through a pipeline; the bottom of the gas cylinder is in flange connection with a piston ring; a head of the cylinder is in threaded connection with an end cover; one end of an oil cylinder sleeve is in threaded connection with the piston ring; the other end of the oil cylinder sleeve is in clearance fit with the end cover; one end of a piston rod is placed in an inner cavity of the oil cylinder in a clearance fit manner; a lug ring on one end of the piston ring is hinged to a rack; the gas cylinder is fixedly connected to the rack. The long-stroke hydraulically-controlled compressor is long in stroke; the liquid compact can be avoided; a moving part is low in speed, low in noise and long in service life; the compressor is wholly prized; a hydraulic control manner is adopted, so that the compressor is flexible and reliable to control; the compressor can be applied to processes of discharging water and extracting gas, mixing and conveying gas and liquid and recycling scattered gas; the compressor is highly adaptive to variable working conditions.