Flexible piston rodTechnical field: a kind of flexible piston rod, be used for the split type compressor compresses piston of high-speed high-power and guiding being connected of crosshead, relate to the manufacturing technology field of gas field natural gas transport supercharging equipment.
Background technique: in the gas gathering and transportation supercharging; airlifting oil recovery; gas production; the hydrogen hydrocarbon reclaims; in the operating modes such as volume increase of decay gas well; all need performance good; the high-power split type compressor that reliability is high could be realized; in high-power split type compressor; all the time be in comparatively abominable operating conditions as the piston rod that connects compressor piston and crosshead compressor in service; bearing very big impulsive load and tension and compression stress; therefore; usually rupture at the screw thread position of piston rod connection crosshead and piston; this fracture is the major accident of Reciprocting piston compressor; in case the reliability that fracture will have a strong impact on the split type compressor of high-speed high-power takes place; the meeting damage equipment; cause equipment downtime; finally cause stopping production, influence the conveying of materials such as rock gas, and then influence the ordinary production of related industry.
Summary of the invention: the present invention is directed to the shortcoming of prior art, rigidity theory such as foundation have designed and a kind ofly can improve the fatigue strength that is threaded, and make the place's transition of screw thread reducing even, the flexible piston rod of rigidity unanimity.
The present invention is achieved in that and comprises piston connecting end, intermediate section and crosshead connecting end, it is characterized in that:
The piston connecting end comprises that rods 4, front and back cooperate section 3,5 and piston connecting thread 1, intermediate section is made of seal shaft 6, the piston connecting end is connected of intermediate section, the crosshead connecting end is connected the other end of intermediate section, and the crosshead connecting end comprises crosshead connecting thread 8 and crosshead connecting thread changeover portion 7;
Cooperate section 3 and back to cooperate between the section 5 before described rods 4 is arranged on, between preceding cooperation section and piston connecting thread, be provided with piston thread changeover portion 2;
The diameter of described rods 4 is 0.85 times of footpath, 1 end of described piston connecting thread, and length is identical with piston length;
Between described crosshead connecting thread 8 and seal shaft 6, be provided with crosshead screw thread changeover portion 7;
Described piston connecting thread 1 and crosshead connecting thread 8 can be screw threads, also can be flanges;
The diameter of described piston thread changeover portion 2 is 0.8 times of the core diameter of thread, and length is 20～30 millimeters, and piston thread changeover portion 2 plays and makes the place's transition of screw thread reducing even, and the fatigue ruption under the stress alternation effect is avoided in the effect of rigidity unanimity;
Piston connecting thread 1 of the present invention and crosshead connecting thread 8 apply the moment of torsion of 1.2 times of original structures by nut, flexible piston rod and piston are linked into an integrated entity, in order to improve performance wear-resisting and sealing, the surface of seal section 6 has high hardness, high-precision relative rubbing surface through nitriding treatment; Compliant section can make the load change amplitude that acts on the piston rod reduce, and reach and improve the intensity that is threaded, the purpose that makes the compliant section and the intensity of thread section be tending towards equating, preceding cooperation section 3 and back cooperation section 5 are used for the location with piston;
Effect of the present invention is: the compliant section of piston rod is tending towards equating with thread section intensity, improve the fatigue strength that is threaded, the changeover portion of connecting thread, make the place's transition of screw thread reducing even, the rigidity unanimity, avoided the fatigue ruption under the stress alternation effect, thereby the whole reliability that has promoted piston rod has guaranteed its long lifetime.
Description of drawings:
Accompanying drawing is a structural representation of the present invention.
Embodiment:
Provide embodiments of the invention below in conjunction with accompanying drawing: the present invention is achieved in that and comprises piston connecting end, intermediate section and crosshead connecting end, the piston connecting end comprises that rods 4, front and back cooperate section 3,5 and piston connecting thread 1, intermediate section is made of seal shaft 6, the surface of seal shaft 6 has high hardness, high-precision relative rubbing surface through nitriding treatment; The piston connecting end is connected of intermediate section, the crosshead connecting end is connected the other end of intermediate section, the crosshead connecting end comprises crosshead connecting thread 8 and crosshead connecting thread changeover portion 7, and piston connecting thread 1 and crosshead connecting thread 8 can be screw threads, also can be flange; Before being arranged on, rods 4 cooperate section 3 and back to cooperate between the section 5, between preceding cooperation section 3 and piston connecting thread 1, be provided with piston thread changeover portion 2, rods 4 can make the load change amplitude that acts on the piston rod reduce, reach and improve the intensity that is threaded, the purpose that makes the rods 4 and the intensity of thread section be tending towards equating, preceding cooperation section 3 and back cooperation section 5 are used for the location with piston; Be provided with crosshead connecting thread changeover portion 7 between crosshead connecting thread 8 and the seal shaft 6;
During use, if what the crosshead of compressor was used is to be threaded, just crosshead connecting thread 8 is screwed in the tapped hole of pressure-increasing machine crosshead, if what the crosshead of compressor was used is that flange connects, just will be connected by screw with compressor crosshead by flange behind crosshead connecting thread 8 adpting flanges; When being connected, the screw thread of piston connecting thread 1 by nut, is applied the moment of torsion of 1.2 times of original structures, flexible piston rod of the present invention and piston are linked into an integrated entity with compressor piston; When seal shaft 6 of the present invention is installed, increase stuffing box packing simultaneously, make seal shaft 6 and filler constitute seal jointly, stop the leakage of gas; The diameter of the rods 4 that is provided with is 0.85 times of piston connecting thread 1 core diameter of thread, length is identical with piston length, its effect is that the load amplitude on the piston rod is reduced, and improves the fatigue resistance that is threaded, and makes it to be tending towards equating with the intensity of piston connecting thread 1; Front and back cooperation section 3 and 5 is used for the location with piston, can guarantee the straightness accuracy requirement of outside piston and piston rod; The diameter of piston thread changeover portion 2 is 0.8 times of the core diameter of thread of piston connecting thread 1, and length is 20～30 millimeters, and piston thread changeover portion 2 plays and makes the place's transition of screw thread reducing even, and the fatigue ruption under the stress alternation effect is avoided in the effect of rigidity unanimity; During work, crosshead is passed through in rotatablely moving of compressor connecting bar major part, make flexible piston rod of the present invention carry out linear reciprocating motion, drive compression cylinder work then, realization is to the compression of gas, the rods 4 that is provided with can effectively make the load amplitude on the piston rod reduce, and has improved the fatigue resistance that is threaded, and can effectively overcome piston rod thread place fracture accident.