Linear compressor with permanent magnets

Abstract

This invention provides a compressor with brushless single-phase linear motor, which includes a movable cylinder associated with a permanent magnet array, at least a stationary electromagnetic winding set and a pair of stationary pistons. A partition plate is disposed in the movable cylinder to form a first sub-cylinder and a second sub-cylinder. The front ends of the pair of the stationary pistons are respectively placed in either of two openings of the movable cylinder at its two ends. An alternate current applied to the stationary electromagnetic winding set to generate alternately attracting/repelling forces to the permanent magnet array. The movable cylinder is hence alternately pushed forward and backward. The volumes of the first and second sub-cylinders are changed to compress air in the first sub-cylinder or the second sub-cylinder.

1 . A linear compressor with permanent magnets comprising:
 a movable cylinder having at least one permanent magnet array and a partition plate, said movable cylinder having one opening formed at each of two ends thereof, said partition plate disposed in said movable cylinder to separate said movable cylinder into a first sub-cylinder and a second sub-cylinder, said permanent magnet array disposed at an outer wall of said movable cylinder in an axial direction thereof and including a plurality of permanent magnets in which adjacent magnets are magnetized oppositely;   at least one stationary electromagnetic winding set disposed at outside of said movable cylinder relative to said permanent magnet array, said stationary electromagnetic winding set including a plurality of lateral branches and a plurality of sub-winding sets, wherein said sub-winding sets are wound in a way that said stationary electromagnetic winding set generates alternate magnetic fields to attract or repel said movable cylinder to move along the axial direction when an alternate current is applied to said stationary electromagnetic winding set; and   a pair of stationary pistons, each of said stationary pistons having a main chamber with a front end thereof placed in the opening of one said end of said movable cylinder and a rear end of said main chamber becoming open, said main chamber having a plurality of sub-chambers and at least two check valves with different flow directions disposed at said front end thereof respectively corresponding to one of said sub-chambers;   wherein said movable cylinder moves forward or backward along the axial direction in response to a phase of the current applied to said stationary electromagnetic winding set, and accordingly changing volumes of said first sub-cylinder and said second sub-cylinder.   
   
   
       2 . The compressor of  claim 1 , further comprising an outer shell for accommodating said movable cylinder, said stationary electromagnetic winding set and the pair of said stationary pistons, wherein said movable cylinder and the pair of said stationary pistons are disposed in a way along an axial direction of said outer shell, and said stationary electromagnetic winding set is disposed at an inner sidewall of said outer shell. 
   
   
       3 . The compressor of  claim 2 , further comprising at least a pair of sliding rails respectively disposed at two opposite positions of one inner wall of said outer shell along the axial direction thereof for guiding the movement of said movable cylinder. 
   
   
       4 . The compressor of  claim 1 , wherein the pair of said stationary pistons guides the movement of said movable cylinder. 
   
   
       5 . The compressor of  claim 1 , wherein said movable cylinder has a plurality of said permanent magnet arrays symmetrically disposed at the outer wall of said movable cylinder, and a plurality of said stationary electromagnetic winding sets are disposed at outside of said movable cylinder respectively corresponding to one of said permanent magnet arrays. 
   
   
       6 . The compressor of  claim 5 , wherein said permanent magnet arrays are disposed at the outer wall of said movable cylinder in a geometric arrangement of cross shape, X shape or triangular shape. 
   
   
       7 . The compressor of  claim 2 , wherein said movable cylinder has a plurality of said permanent magnet arrays symmetrically disposed at the outer wall of said movable cylinder, and a plurality of said stationary electromagnetic winding sets is disposed at the inner wall of said outer shell respectively corresponding to one of said permanent magnet arrays. 
   
   
       8 . The compressor of  claim 7 , wherein said permanent magnet arrays are disposed at the outer wall of said movable cylinder in a geometric arrangement of cross shape, X shape or triangular shape. 
   
   
       9 . The compressor of  claim 1 , wherein said partition plate is detachable. 
   
   
       10 . The compressor of  claim 1 , further comprising a magnetic-conductive material disposed between said permanent magnet arrays and the outer wall of said movable cylinder. 
   
   
       11 . A linear compressor with permanent magnets, comprising:
 a first movable cylinder having at least one first permanent magnet arrays and a first partition plate, said first movable cylinder having one opening respectively formed at each of two ends thereof, said partition plate disposed in said first movable cylinder to separate said first movable cylinder into a first sub-cylinder and a second sub-cylinder, said first permanent magnet array disposed at an outer wall of said first movable cylinder in an axial direction thereof and having a plurality of permanent magnets in which adjacent magnets are magnetized oppositely;   a second movable cylinder having at least one second permanent magnet arrays and a second partition plate, said second movable cylinder having one opening respectively formed at each of two ends thereof, said second partition plate disposed in said second movable cylinder to separate said second movable cylinder to a third sub-cylinder and a fourth sub-cylinder, said second permanent magnet arrays disposed at an outer wall of said second movable cylinder along an axial direction thereof and having a plurality of permanent magnets in which adjacent magnets are magnetized oppositely;   at least a first stationary electromagnetic winding set disposed outside said first movable cylinder relative to said first permanent magnet array, said first stationary electromagnetic winding set including a plurality of lateral branches and a plurality of sub-winding sets, wherein said sub-winding sets are wound in a way that said first stationary electromagnetic winding set generates alternative positive and negative magnetic fields to attract or repel said first movable cylinder to move along the axial direction when an alternate current is applied to said first stationary electromagnetic winding set;   at least a second stationary electromagnetic winding set disposed outside said second movable cylinder relative to said permanent magnet array, said second stationary electromagnetic winding set including a plurality of lateral branches and a plurality of sub-winding sets, wherein said sub-winding sets are wound in a way that said second stationary electromagnetic winding set generates alternate positive and negative magnetic fields to attract or repel said second movable cylinder to move along the axial direction when a alternate current is applied into said second stationary electromagnetic winding set;   a first stationary piston having a first main chamber with a front end thereof placed in the opening of one said end of said first movable cylinder and a rear end thereof becoming open, said first main chamber including a plurality of first sub-chambers with a front end thereof provided with at least two check valves having different flow directions respectively corresponding to one of said first sub-chambers;   a second stationary piston having a second main chamber with a front end thereof placed in the opening of one said end of said second movable cylinder and a rear end thereof becoming open, said second main chamber including a plurality of second sub-chambers with a front end thereof provided with at least two check valves having different flow directions respectively corresponding to one of said second sub-chambers; and   a third stationary piston having a third main chamber, said third main chamber having two third sub-chambers, an outlet passage and an inlet passage, a front end of said third main chamber placed in the opening of the other end of said first movable cylinder and a rear end thereof placed in the opening of the other end of said second movable cylinder, the front and rear ends of said third main chamber respectively provided with two check valves with different flow directions corresponding to said third sub-chambers, said outlet passage formed at one side of one of said third sub-chambers, and said inlet passage formed at one side of the other one of said third sub-chambers;   wherein said first movable cylinder and said second movable cylinder move forward or backward along the axial direction in response to a phase of the current applied to said first stationary electromagnetic winding set and said second stationary electromagnetic winding set.   
   
   
       12 . The compressor of  claim 11 , further comprising an outer shell for accommodating said first movable cylinder, said second movable cylinder, said first stationary electromagnetic winding set, said second stationary electromagnetic winding set, said first stationary piston, said second stationary piston and said third stationary piston, wherein said first and second movable cylinders and said first, second and third stationary pistons are disposed along an axial direction of said outer shell, said first and second stationary electromagnetic winding sets are disposed at an inner wall of said outer shell. 
   
   
       13 . The compressor of  claim 12 , further comprising at least a pair of sliding rails disposed at two opposite positions of the inner wall of said outer shell along the axial direction thereof for guiding the movement of said first and second movable cylinders. 
   
   
       14 . The compressor of  claim 11 , wherein said first, second and third stationary pistons guide the movement of said first, second and third movable cylinders. 
   
   
       15 . The compressor of  claim 11 , wherein a plurality of first permanent magnet arrays and a plurality of second permanent magnet arrays respectively and symmetrically disposed at an outer wall of said first movable cylinder and said second movable cylinder, and a plurality of said first stationary electromagnetic winding sets and a plurality of said second stationary electromagnetic winding sets are respectively disposed outside said first movable cylinder and said second movable cylinder corresponding to said first permanent magnet arrays and said second permanent magnet arrays. 
   
   
       16 . The compressor of  claim 15 , wherein said first permanent magnet arrays and said second permanent magnet arrays are respectively disposed at the outer walls of said first movable cylinder and said second movable cylinder in a geometric arrangement of cross shape, X shape or triangular shape. 
   
   
       17 . The compressor of  claim 11 , wherein said first partition plate and said second partition plate are detachable. 
   
   
       18 . The compressor of  claim 11 , further comprising a first magnetic-conductive material disposed between said first permanent magnet array and the outer wall of said first movable cylinder and a second magnetic-conductive material disposed between said second permanent magnet array and the outer wall of said second movable cylinder. 
   
   
       19 . A two stage linear compressor with permanent magnets comprising:
 a movable cylinder having at least one permanent magnet array and a partition plate, said movable cylinder having one opening formed at each of two ends thereof, said partition plate having at least one interstage check valve and disposed in said movable cylinder to separate said movable cylinder into a first sub-cylinder and a second sub-cylinder, said permanent magnet array disposed at an outer wall of said movable cylinder in an axial direction thereof and including a plurality of permanent magnets in which adjacent magnets are magnetized oppositely;   at least one stationary electromagnetic winding set disposed at outside of said movable cylinder relative to said permanent magnet array, said stationary electromagnetic winding set including a plurality of lateral branches and a plurality of sub-winding sets, wherein said sub-winding sets are wound in a way that said stationary electromagnetic winding set generates alternate magnetic fields to attract or repel said movable cylinder to move along the axial direction when an alternate current is applied to said stationary electromagnetic winding set;   a first stationary pistons, said first stationary pistons having a main chamber with a front end thereof placed in the opening of said first sub-cylinder and a rear end of said main chamber becoming open, said main chamber having at least one intake check valve disposed at said front end thereof; and   a second stationary pistons, said second stationary pistons having a main chamber with a front end thereof placed in the opening of said second sub-cylinder and a rear end of said main chamber becoming open, said main chamber having at least one discharge check valve disposed at said front end thereof;   wherein said movable cylinder moves forward or backward along the axial direction in response to a phase of the current applied to said stationary electromagnetic winding set, and accordingly changing volumes of said first sub-cylinder and said second sub-cylinder, a working fluid is drawn into said first sub-cylinder through said intake valve and is compressed and transferred through said interstage valve into the said second sub-cylinder piston in a first stage of compression, and further is compressed and transferred out of said second sub-cylinder through said discharge valve, in a second stage of compression.   
   
   
       20 . The compressor of  claim 19 , further comprising an outer shell for accommodating said movable cylinder, said stationary electromagnetic winding set and the said first and second stationary pistons, wherein said movable cylinder and the said stationary pistons are disposed in a way along an axial direction of said outer shell, and said stationary electromagnetic winding set is disposed at an inner sidewall of said outer shell. 
   
   
       21 . The compressor of  claim 20 , further comprising at least a pair of sliding rails respectively disposed at two opposite positions of one inner wall of said outer shell along the axial direction thereof for guiding the movement of said movable cylinder. 
   
   
       22 . The compressor of  claim 19 , wherein the said first and second stationary pistons guides the movement of said movable cylinder. 
   
   
       23 . The compressor of  claim 19 , wherein said movable cylinder has a plurality of said permanent magnet arrays symmetrically disposed at the outer wall of said movable cylinder, and a plurality of said stationary electromagnetic winding sets are disposed at outside of said movable cylinder respectively corresponding to one of said permanent magnet arrays. 
   
   
       24 . The compressor of  claim 23 , wherein said permanent magnet arrays are disposed at the outer wall of said movable cylinder in a geometric arrangement of cross shape, X shape or triangular shape. 
   
   
       25 . The compressor of  claim 19 , further comprising a magnetic-conductive material disposed between said permanent magnet arrays and the outer wall of said movable cylinder. 
   
   
       26 . The compressor of  claim 19 , wherein an outer diameter of said second stationary piston and an inner diameter of said second sub-cylinder are smaller than that of said first stationary piston and said first sub-cylinder, respectively.